Organisers: IAMAS (ICCL), IAVCEI
Lead Convenors: Michael MacCracken ( United States of America), Alan Robock (United States of America)

Scope: With the pace of climate change increasing and the array and magnitude of climate impacts intensifying, increasing attention is being paid to the potential for limiting the effects of anthropogenic climate change through large-scale technical means, often called geoengineering. Possible approaches include deliberately altering the Earth's radiation balance, and intervening in the carbon cycle or other biogeochemical cycles, for example via carbon scrubbing and sequestration. Although specific approaches have been proposed, relatively little is known about their potential effectiveness for moderating climate change and possible unintended consequences. Issues of technological feasibility are also largely unexplored. Papers are invited that describe and address the potential effectiveness and scientific and technical problems associated with deliberate climate modification, including enhancement of terrestrial and oceanic carbon sinks. Possible examples include modeling studies of the climatic impacts of proposed schemes for altering the absorption of solar radiation; studies of unintended environmental consequences; and evaluations of technological feasibility issues. Papers on historical, ethical, and governance issues are also welcome.

Keywords: geoengineering, global warming, climate intervention, carbon scrubbing, solar radiation management

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors. This joint symposium is closely linked to the Union symposium U-06, which consists of solicited presentations only.

Organisers: IAMAS (ICDM, ICMA), IAPSO, IAHS, IAGA, IACS
Lead Convenor: William Lahoz (Norway)
Co-convenors: Craig Bishop (United States of America), Mu Mu (China), Michele Rienecker (United States of America), Jeffrey Walker (Australia), Tomoko Matsuo (United States of America), Ian Fenty (United States of America)
           
Scope: The session will provide a forum for presentation and discussion of the latest research in data assimilation and ensemble forecasting. The effectiveness of data assimilation and ensemble forecasting is inextricably linked to our ability to estimate the distribution of truth given limited information. Given imperfect and sparse observations together with an imperfect forecasting system, data assimilation focuses on estimating the distribution of current and past states while ensemble forecasting strives for the distribution of future states. Data assimilation schemes need an estimate of the distribution of truth given a short term forecast – a key objective of ensemble forecasting. The intertwining of the aims of data assimilation and ensemble forecasting makes it likely that data assimilation experts can help ensemble forecasting experts and vice-versa. We are calling for presentations of outstanding research in data assimilation and ensemble forecasting. Particular data assimilation topics include:

• Advanced assimilation methods, including hybrid variational and ensemble-based approaches, weak constraint 4D-VAR and model error estimation;
• Improved use of observations: observing system experiments and observing system simulation experiments, adaptive observing methods, calculation of observation sensitivities;
• Assimilation of data from new satellite instruments, such as COSMIC, CloudSat, IASI, SMOS, Aquarius and ADM-Aeolus;
• Space Weather, including applications to the heliosphere, the magnetosphere, and the ionosphere-thermosphere system;
• Polar assimilation: exploiting the considerable data collected during the IPY and subsequently via the Arctic Observing Network.

Contributions on ensemble forecasting for short, medium, seasonal and climate time scales are all welcome. Specific sub-topics include:

• improved methods for initializing ensemble forecasts,
• estimation and representation of model error, and
• ensemble post-processing to optimize the value of probabilistic forecasts to decision makers.

Keywords:  observations, satellite data, advanced methods, decision makers

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers:  IAMAS (ICCL), IAPSO
Lead Convenor: Richard Bouchard (United States of America)
Co-convenors:  Keith Alverson (France), Thierry Fichetet (Belgium)

Scope: This symposium takes it cue from the wide-spread, global efforts to advance the understanding of climate issues, such as climate change, climate variability, and climate adaptation by observing the world around us, as evidenced by the densification and advancement of a variety of direct and proxy observations provided by mixture of in situ and remotely-sensed observing systems.  Recent years have seen those efforts culminate with nearly world-wide participation in the Global Earth Observing System of Systems (GEOSS), the maturation of individual regional observing systems, the fielding of new satellite and observing systems, and advances in observations of and which span the air-sea, sea-ice, land-sea, and atmospheric structure boundaries. However, many of these advances and the sustainability of observing systems themselves may have been impacted by the changing state of the global economy since the heady days of IUGG XXIV in 2007.

While the observations themselves provide valuable insights on climate issues by trend analysis, the validation of model hindcast, and short-term model prediction, the application of the observations can serve greater utility by their proper and rigorous integration through time-tested or novel data assimilation schemes.

Sample topic areas include assimilating disparate and perhaps conflicting observations into climate analysis and modelling; the application of earth observations in support of climate adaptation strategies; climate monitoring; status and plans of existing and planned observing systems; observation and assimilation of stable water isotopes; techniques and parameters that provide continuity and target fluxes across interfaces, such as the land-sea interface, sea-ice interface,  the tropopause, the stratopause, and the mesopause; effects of the global economic change on sustaining established and planned climate observing systems; and, the role of climate principles in fielding new technologies for the sustainability of observing systems.

Keywords: Global observation systems, GEOSS, climate modelling

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers:  IAMAS (ICMA, ICDM, ICCL), IAPSO
Lead Convenor: Elisa Manzini  (Italy)
Co-convenors: Joan Alexander (United States of America), Greg Roff (Australia)

Scope: Stratospheric variability and change are now recognized to have an active role in troposphere-stratosphere dynamical coupling. In investigating climate and its variations, it is therefore of interest to address the full stratosphere-troposphere-ocean system.

The aim of this symposium is to invite contributions from theoretical, observational and modeling studies on the interactions between the stratosphere, the troposphere and the ocean. Topics of particular interest include but are not limited to

• mechanisms of the two-way dynamical coupling among the layers and their relevance for weather to climate time scales
• importance of the interaction with the ocean to understand the role of the stratosphere in climate
• predictability of the stratosphere-troposphere-ocean system at seasonal and decadal time scales
• stratospheric change and the role of ozone recovery in climate with coupled atmosphere-ocean models with a well-resolved stratosphere
• coupling within the tropical stratosphere-troposphere ocean system, with emphasis on understanding tropical variability and interactions across different time and spacial scales

Keywords: Air-sea interaction, down-ward control, ozone recovery

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organsiers:  IAMAS (ICPM), IAPSO, IACS
Lead Convenor: Siobhan O’Farrell (Australia)
Co-convenors: Jason Box (United States of America), David Reusch (United States of America), Michael Town (France)

Scope: This last decade has seen record sea ice-extent minima in the Arctic while the Antarctic has shown no change in sea ice extent.  At the same time, the Greenland ice sheet, Antarctic Peninsula ice shelves and West Antarctic outlet glaciers and surface temperatures all exhibit increasing evidence of change. The combined effects of anthropogenic forcing and natural variability modes are thus yielding different responses in the atmospheric, oceanic, and cryospheric components of the two polar climate systems.
This session will investigate the contrasting climate responses in atmosphere, ocean and cryosphere, through several key questions:
(1) Where can we detect the anthropogenic signal in the polar climate system (e.g., temperature, sea level pressure, sea ice extent, ocean currents, ocean water mass properties, etc.)? 
(2) Can we identify how the large-scale natural variability also driving the climate system affects these same climate variables, whether the changes exceed natural variability “noise” levels in the system, and does reality mirror model-projected change?

We solicit papers from the atmospheric, oceanic and cryospheric communities, from observational, theoretical and modelling perspectives, addressing these questions and the role of natural variability and/or anthropogenic signals in individual climate components, or across the climate system.

Keywords:  climate response, climate detection, cryosphere, modes of variability, climate variables, ocean water mass changes.

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organsiers: IAMAS (ICCL, ICDM), IAHS
Lead Convenors: Xuebin Zhang (Canada), Richard Swinbank (United Kingdom), Ronald Stewart (Canada)
Co-convenors:  Lisa Alexander (Australia), Istvan Szunyogh (United States of America), Jun Xia (China), Richard Grotjahn (United States of America), Olga Zolina (Germany), Siegfried Schubert (United States of America)

Scope: Extremes are an inherent aspect of the climate system. Such extremes are of different spatial and temporal scales, including for example, tornados, heavy precipitation and flooding, ice storms, tropical and extratropical cyclones, storm surges, heat and cold waves, drought as well as related phenomena. Many of these extremes may be compound events, resulting from several factors. This symposium covers a wide range of topics related to high-impact weather and extreme climate events, from both short-term weather forecast and long-term climate change perspectives.

One focus is on the dynamics and predictability of extreme climate and weather events and improving forecasts of high-impact weather in the current climate. This paradigm is addressed by WWRP/THORPEX - an international research programme to accelerate improvements in the prediction of high-impact weather on short- to medium-range timescales. Scientific studies based on THORPEX field campaigns (such as T-PARC or T-NAWDEX) or related research projects will be particularly welcome.

Another focus follows from the concern that a change in the climate, especially an accelerating water cycle, may lead to more such extreme events. The ensuing impacts depend more on the changes in extremes than on changes in the mean state of the climate. This is addressed, for example, by various WCRP projects (e.g. CLIVAR, GEWEX and CliC). Presentations are requested on a range of issues within this topic area including the global distribution of weather and climate extremes; trends in frequencies and intensities of extremes; development of new tools and methods for the quantitative analysis of extremes; understanding the mechanisms responsible for the formation and evolution of extremes; as well as projections of extremes and associated uncertainties in the future climate.

Keywords:  Seamless prediction, WCRP, WWRP, THORPEX

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers:  IAMAS (ICPAE), IACS
Lead Convenor: Dimitri Titov (Germany)
Co-convenors:  Ralf Greve (Japan), Athéna Coustenis (France)

Scope: Papers are invited on the physics and chemistry of the lower, middle and upper atmosphere, ionosphere and surface ice of the inner planets and comets. Comparative studies of the atmospheres of Venus, Earth and Mars, as well as the ices on Earth and Mars, are also invited, with emphasis on the differences and similarities in their climates. Results from recent missions to Mars, Venus and the terrestrial planets in general are of particular interest. Reports on improvements in general circulation models of the thermosphere and lower atmospheres of the planets, coupled atmosphere/cryosphere models and descriptions of future planetary missions are also invited, as well as advances in laboratory experiments.

Keywords: Physics, chemistry, planetary atmospheres

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers: IAMAS (ICCL, ICDM), IAPSO , IACS
Lead Convenor: Natalia Andronova (United States of America)
Co-convenors: Neil Holbrook (Australia), John Nielsen-Gammon (United States of America), Adam Scaife (United Kingdom), Toshio Yamagata (Japan), Petra Heil (Australia)

Scope: Effective adaptation to climate change requires specific probabilistic forecasts of the future state of global and regional climate years to decades in advance.  While much can be learned from studies of the predictability of weather, the future state of the climate system involves the coupled evolution of the atmosphere, oceans, surface water, ice sheets and glaciers, and society (emissions and land use), all of which have widely varying levels of observability and model fidelity, and the entire system is further subject to time-varying external solar and volcanic forcing.  Sensitivity of the climate system to external forcing greatly depends on a wide variety of feedbacks that govern interactions within the climate system. Quantifying the climate feedbacks operating on different spatial and temporal scales has been a great challenge for the climate community, making it difficult to provide clear and adequate scientific information to policymakers. The different temporal and spatial scales of interactions within the whole climate system bring great uncertainties into the analysis of climate sensitivity and feedbacks.  This translates into uncertainties of climate prediction, particularly on regional scales, and requires a close conversation between climate modelers, observatories and stakeholders.

Papers are invited on all aspects of climate sensitivity, predictability and feedbacks from annual to centennial time scales, including: the predictability and sensitivity to initial conditions of individual components of the climate system; nonlinear interactions among components and their effects on predictability; the nature of observations which have or would have the greatest impact on climate predictability; the extent to which climate predictability is sensitive to societal responses to climate change; the spatial and temporal scale dependence of climate predictability; the importance (and probabilistic specification) of time-varying external forcing; and the proper framing of probabilistic climate forecasts to meet societal needs.

Keywords: Probablilistic forecasts, feedbacks, time scales

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers: IAMAS (ICMA), IAGA
Lead Convenor: Alexei Krivolutski (Russia)
Co-convenors:  Jan Lastovicka (Czech Republic)
                       
Scope: This symposium focuses on new results, which demonstrate the response of the middle atmosphere and lower ionosphere composition and dynamics to short/long-term forcing caused by solar UV variations, energetic particles, and various processes associated with geomagnetic storms. The results obtained by ground based or satellite observations, and also by model simulations are welcome. The analysis and modelling of the behaviour of atmospheric tides during intense external forcing periods, and chemical neutral and ion compositions during the influence of meteorite fluxes are encouraged.

Keywords: High atmosphere, satellite observations, modelling studies, external forcing

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers: IAMAS (ICCL,ICDM), IAPSO, IACS, IAHS,GEWEX, CLIVAR
Lead Convenors: Jianping Li (China), John McBride (Australia)
Co-convenors: Bin Wang (United States of America), Jun Matsumoto (Japan), Harry Hendon (Australia), E. Hugo Berbery (United States of America), Richard Grotjahn (United States of America), Michael Montgomery (United States of America), Roger K. Smith (Germany), Masato Sugi (Japan), Georg Kaser (Austria), David S. Nolan (United States of America)
                       
Scope: This is a wide-ranging symposium covering many aspects of tropical weather and climate, but focusing primarily on monsoons and tropical cyclones, which affect the lives of billions of people. It is of great importance to understand the dynamics of monsoons and tropical cyclones, to predict them and project future changes in their nature associated with global warming. This symposium invites contributions regarding observational, diagnostic, theoretical and modeling studies of the nature, variability and mechanisms of monsoons, tropical cyclones and other tropical phenomena.  Presentations about the impact of climate change on tropical circulations are particularly welcome.

The symposium will be focused on the following themes:

• Theme 1.  Monsoon nature and mechanisms of monsoon variability. Monsoons are fundamental regulators of the earth’s energy budget and water cycle, impacting people across Southern Asia and other tropical and subtropical regions around the globe.  This part of the symposium focuses on the nature and mechanisms of monsoon variability at intraseasonal, interannual to millennial timescales; linkages between monsoon and the principal modes of climate variability; air-sea-land interaction within the global monsoon system; monsoon simulation, predictability, prediction and projection. Presentations are also invited on the latest results from monsoon experiments such as the AMY, SCSMEX, MAHASRI, GAME, NAME, MESA and AMMA, etc.
• Theme 2. Tropical cyclones. Tropical cyclones are the most destructive weather systems on the planet. We do not yet fully understand the processes that determine their development and movement to the extent that their properties can be forecasted with precision over a time scale of several days. Research papers are solicited on all aspects of tropical cyclones, especially those concerned with the fundamental dynamical and thermodynamical processes involved as well as the genesis, intensification, movement, and impacts.
• Theme 3.  Tropical circulations. This part of the symposium concerns the diverse range of tropical circulations, including equatorial waves, organized tropical convection, and tropical intraseasonal and inter-annual variability. The symposium will cover the Madden-Julian Oscillation, El Nino Southern Oscillation, the Walker and Hadley Circulations, and their interaction with monsoons and tropical cyclones.  Contributions on the diverse linkages between the tropics, subtropics and midlatitudes are also invited.  We seek to advance and connect understanding in these areas by bringing together diagnostic, theoretical, idealised and realistic simulation, prediction and model intercomparison approaches.

Keywords:Monsoon, Tropical cyclones, tropical circulations, ENSO

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers:  IAMAS (ICCL), IAPSO, IACS
Lead Convenor: Michael MacCracken (United States of America)
Co-convenors:  Valérie Masson-Delmotte (France), Alan Robock (United States of America)

Scope: Earth system history makes clear that the climate can span a wide range of states, from widespread glaciation to global warmth with very little ice at all, essentially from what might be called to being dominated by the world’s ice to dominated by the atmosphere’s greenhouse gas concentrations. This symposium, which will have a number of components, is intended to span the spectrum, inviting papers on periods from when the climate was very cold to when it has been hot and including the warming Earth that human activities are now inducing. Papers relating to model development and verification, including determining climate sensitivity, should be submitted to J-M08. Papers relating to the nature of cold to hot climates, transitions from one state to the other, and particularly the transition from the Holocene to the present and into the future should be submitted to this Symposium. Studies and analyses based on observational records (e.g., ice core records) and modelling are both invited, and especially studies that draw from both. The causes of both stability and change are of interest, including the ranges of natural variability and the coupling of changes in climate to the weather, oscillations, and extremes that result.

The components of the Symposium are envisioned to be:

• Pre-Pleistocene warm and cold climates—Insights into the long-term functioning of the climate system
• Glacial cycling during the Pleistocene—A period of large climate swings and feedbacks;
• The Holocene: Its stability and variations—and their causes; and
• The Industrial Era and beyond, covering the response of the climate system to human activities (including particularly reports on model simulations being done for IPCC’s AR5 report)

Keywords: Geological time scales, climate variations, proxy data

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers:  IAMAS (ICAE), IAGA (Division II)
Lead Convenors: Colin Price (Israel), Fernanda T. São Sabbas (Brazil)
Co-convenors:  Gabriella Satori (Hungary), Elisabeth Blanc (France)

Scope: Thunderstorms are an important component of the Earth's weather and climate.  While thunderstorms can be associated with severe weather, and associated natural hazards, they also impact global atmospheric circulation, atmospheric chemistry and the global electric circuit.  Thunderstorms are also related to the recently discovered Transient Luminous Events (TLEs) and Terrestrial Gamma Ray Flashes (TGFs) in the upper atmosphere. TGFs show the large energy exchanges between the Earth's atmospheric layers. Global thunderstorm activity is modulated by solar forcing on many spatial and temporal scales, from local to global, and from daily to inter-annual scales. Thunderstorms are also a source of gravity waves and infrasound.

This session welcomes papers in all aspects related to the meteorology and climatology of thunderstorms, their dynamical and electrodynamical coupling to different layers of the atmosphere, including ionospheric and magnetospheric effects, and similar processes on other planets.

Keywords: thunderstorms, lightning, sprites, severe weather, TLEs, mesosphere, ionosphere, global electric circuit, climate

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers: IAMAS(ICCP), IAHS
Lead Convenor: Daniel Schertzer (France)
Co-convenors:  Sandra Yuter (United States of America), Alan Seed (Australia)

Scope: The extreme variability of precipitation over a wide range of space-time scales remains a challenging research domain for both the observation and modelling domains. Since this variability is rather discrete in time and discontinuous in space, methods developed for more continuous variables such as velocity and pressure are often not adequate for precipitation. A better understanding and representation of the spatial and temporal structure of rainfall is therefore an indispensable step when designing a rain gauge network, gauge data quality checking and removing artifacts, quantifying and modeling the error structure for radar rainfall, estimating the predictability limits as a function of scale and lead time and developing algorithms for very short term precipitation forecasts (e.g. some form of advection forecast).

This joint IAHS-IAMAS workshop will be a forum to discuss observed precipitation from long-records and new observational in-situ networks and remote sensing data sets. Particular attention will be paid to characterization and methodologies related to extreme events, non-stationarities, multiplicity of scales, effective space-time resolution, quantification of uncertainties and empirical descriptions that can be incorporated into downscaling and numerical model frameworks.

Keywords: precipitation, long records, extreme events, non-stationarities, multiplicity of scales, effective space-time resolution, uncertainty quantification, empirical descriptions, downscaling and numerical models

Review: All contributed abstracts will be reviewed by the convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.

Organisers: IAMAS (IRC)
Lead Convenor: Mario Blumthaler (Austria)
Co-convenors:  Julian Gröbner (Switzerland)

Scope: This symposium invites papers with the focus on: new methods for the determination of Solar UV radiation from ground and from space, development of UV instruments and networks; the temporal and spatial variability of solar UV (back and into the future) due to variable atmospheric conditions, and especially in the variable local human environment; effects of solar UV on humans, biosphere (inclusive water) and air chemistry, also considering the diversity of biological weighting.

Organisers:  IAMAS (ICMA, ICACGP, ICCL, IOC, IRC)
Lead Convenor: Laura Pan (United States of America)
Co-convenors:  Greg Bodeker (New Zealand), John Burrows (Germany), Martin Dameris (Germany), Sophie Godin-Beekmann(France), Yutaka Kondo (Japan), Eugene Rozanov (Switzerland), Donald Wuebbles (United States of America)

Scope: Atmospheric chemistry affects climate by controlling the concentration and spatial distributions of a large number of important climate forcing agents. Changes in climate in turn significantly affect atmospheric chemistry and thereby atmospheric composition. This special symposium invites presentations on key issues of chemistry-climate interactions.  Both observations and modeling studies are invited as well as integrated studies using both model and observations in a synergistic way. The topics include but are not limited to the following three areas:

• Chemical processes and their impact on climate
  This area focuses on all climate relevant chemical processes in the troposphere and stratosphere. Specific topics include the climate impact of the replacements for ozone-depleting substances (ODSs), the effect of ozone changes on atmospheric circulation and surface climate, the chemical impact of the pollutants on weather and climate, measurements of radiatively significant short and long lived constituents and their surface fluxes, direct and indirect climate forcing of the aerosol chemistry, and the role of water vapor in middle atmosphere chemistry and climate.
• Climate related circulation changes and their impact on atmospheric chemistry
  This area comprises changes in atmospheric circulation, including Brewer-Dobson circulation, state of the polar vortices, wave forcing, Monsoon circulation, and tropospheric weather patterns, and their impact on stratospheric ozone changes, on transport and chemistry of trace species and aerosols, and on age of air in the stratosphere. Changes in the troposphere include changes in global tropopause region, impact on chemical gradients across the UTLS, and latitudinal expansion of tropics.
• Model predictions and attribution of chemistry-climate interactions
  This area focuses on prediction and attribution. Some examples are the significance of including chemistry in global climate models and GCMs, identifying key elements of chemical processes that matter for climate modeling, process-oriented studies to clarify the cause-and-effect relationships of physical, dynamical and chemical processes and its changes, and future assessments of chemistry-climate connections.

Organisers:  IAMAS  (ICCP, ICCL, IRC)
Lead Convenors: Graham Feingold (United States of America), Ilan Koren (Israel)
Co-convenors:  Graeme Stephens(United States of America), Vanderlei Martins (United States of America), Steve Siems (Australia)
                       
Scope: Despite decades of research into the relationship between aerosol, clouds and precipitation, there is still considerable uncertainty regarding (1) the radiative and hydrological implications of aerosol-cloud interactions, and (2) our ability to quantify these interactions, particularly with remote sensing methods. This symposium will focus attention on aerosol-cloud-radiation-precipitation processes, with these two topics as unifying themes. We invite papers on recent progress in observational, theoretical and modelling studies addressing interactions of the aerosol with warm, mixed-phase and ice clouds, the hydrological cycle, and feedbacks amongst cloud microphysical, dynamical and radiative processes. Studies that attempt to separate aerosol-induced changes in cloudiness and precipitation from those associated with meteorology will be welcomed.

Organisers:  IAMAS (ICMA)
Lead convenor: Shigeo Yoden (Japan)
Co-convenors: Bernd Funke (Spain), Takeshi Horinouchi(Japan), Damian Murphy (Australia), Cora Randall (United States of America)

Scope: This is the core symposium of ICMA (International Commission on the Middle Atmosphere). Papers related to any aspect of the dynamics, chemistry, or physics of the atmosphere from near the tropopause to the lower thermosphere are appropriate for this symposium. Observational, modeling, theoretical, and laboratory studies are all solicited. In particular, investigations of the middle atmosphere in the context of climate of the whole atmosphere are encouraged. Research topics include (but are not limited to):

• middle atmosphere responses to anthropogenic climate change and other external forcings
• middle atmosphere influences on long-term changes in both the troposphere and upper atmosphere
• stratospheric/mesospheric chemistry and ozone
• radiation, microphysics, chemistry and dynamics in the TTL or the extratropical UTLS
• dynamics, transport and mixing in multiple spatial scales
• observations and modeling of gravity waves
• intraseasonal and interannual variations in the middle atmosphere
• remote influences in the middle atmosphere, including tropical/extratropical interactions, vertical couplings in the tropics and polar regions.
  

We specially invite new results that will provide new insights into the science of the middle atmosphere in a changing climate.

Organisers: IAMAS (ICPAE)
Lead Convenor: Athena Coustenis (France)
Co-convenors:  Darrell Strobel (United States of America), Frank Mills (Australia)      

Scope: Papers are invited which report progress on all aspects of our current understanding of the evolution of atmospheres of the outer planets, their moons and their interactions with their environment (rings, magnetosphere, surfaces). The emphasis will be on insights gained from recent space missions, including Cassini-Huygens and Earth-orbiting satellites. Contributions describing the atmosphere-related objectives of the relevant missions, analysis of observations, and the results of model simulations of atmospheric evolution are also welcome. Research on exoplanetary atmospheres in comparison to the ones in our solar system is also of relevance. The relation of all of these aspects to the field of Astrobiology shall be put forward.

Organisers: IAMAS (ICCP)
Lead Convenor: Ulrich Pöschl (Germany)
Co-convenors:  Cindy Morris (France)

Scope: Bioaerosols consisting of primary biological particles such as bacteria, spores and pollen are essential for the spread of organisms in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The sources and diversity, atmospheric abundance and transport, physicochemical properties and transformation of bioaerosols, including their activity as cloud condensation and ice nuclei (CCN, IN), are not well characterized. Thus, their actual influence on the evolution, present state and future development of the Earth system, the hydrological cycle and other biogeochemical cycles is poorly constrained. These topics are addressed in a growing number of investigations comprising field measurements, laboratory experiments and model studies involving scientists from a wide range of scientific disciplines (biology, chemistry, physics; atmospheric and climate science; bio-geosciences). In the proposed session, the current state of knowledge shall be outlined, and the challenges and perspectives of future research shall be explored. Connections between related disciplines, Earth system compartments and research activities shall be emphasized, and gaps shall be bridged

Organisers: IAMAS (ICDM)
Lead Convenor: Nili Harnik (Israel), Michael Reeder (Australia), Roger Smith (Germany)
Co-convenors:  Eyal Heifetz (Israel), Hisashi Nakamura (Japan), Jim Renwick (New Zealand), Jorgen Frederiksen (Australia)

Scope: This session focuses on the application of geophysical fluid dynamics and turbulence theory to the understanding of the atmospheric circulation and climate. This includes the interaction between dynamics and other processes such as radiation, as well as the influence of topography and other boundary asymmetries.  The emphasis will be on dry and moist dynamics of synoptic to planetary scale atmospheric circulations, both in the troposphere and stratosphere.  Contributions based on theoretical, diagnostic, and modeling (either realistic or idealized) studies are invited on a range of topics including, but not limited to, wave and cyclone growth and evolution, eddy-mean flow interactions and possible dynamical regimes arising from it, the dynamics of storm tracks and jet streams, the dynamics of the stratospheric polar vortex, and its interaction with the troposphere, topographic and/or oceanic influence on large-scale atmospheric circulation, interactions between moist convection and large-scale flows and dynamical implications of aerosol-cloud-climate interactions.
Contributions are sought also for a Special Session in honour of Emeritus Professor Bruce Morton, who
has been a leading figure in Australian Meteorology. The Special Session will focus on the structure and
dynamics of subtropical or tropical weather systems that are influenced by deep dry convection such as
heat lows, inland troughs, convergence lines, low-latitude cold fronts, dry lines and sea breezes.

Organisers:  IAMAS (ICMA, IRC, ICAE, ICCL, ICCP, IOC)
Lead Convenor: Ulrike Langematz (Germany)
Co-convenors:  Werner Schmutz (Switzerland), Lon L. Hood (United States of America), Victor Fomichev (Canada), Joanna Haigh (United Kingdom), Tom Woods(United States of America)

Scope: The session will address all aspects of the impact of solar variations on the Earth’s atmosphere and oceans. These include:

• the response to variations in total and spectral electromagnetic radiation
• the response of the atmosphere to energetic particles precipitating from the space
• the identification of mechanisms and interactions leading to indirect solar effects
• the impact of solar activity on tropospheric meteorological processes and climate

The symposium invites contributions on identifying the solar signal from ground-based and satellite observational datasets ranging from the upper atmosphere (thermosphere, mesosphere) to the stratosphere, the troposphere, the Earth's surface and the oceans. Papers on the solar irradiance and particle flux on Earth are welcome as well as contributions on physical and chemical processes and mechanisms leading to the observed solar signal. Simulations with mechanistic, general circulation and chemistry climate models are especially encouraged. Studies may include solar variations on different time scales ranging from the 27-day rotation period over the 11-year solar cycle to centennial and millennial variations including the Maunder Minimum. Foci will be atmospheric-climate changes over the solar cycle time period, especially in relation to the 2007-2009 cycle minimum, and the interaction of solar variability with the oceans.

Organisers:  IAMAS (IRC)
Lead Convenor: Alexander Marshak (United States of America)
Co-convenors:  Bernhard Mayer (Germany)

Scope: We invite papers on modeling and observations involving three-dimensional (3D) radiative transfer (RT) applications to the Earth's atmosphere and surface (vegetation, land and sea ice). We are interested in aspects of solar ultraviolet (UV) radiation (e.g. actinic flux; irradiance on horizontal and tilted receivers including biological ones); visible and near-infared radiation with applications to solar radiative transfer and remote sensing; and 3D effects due to variations in thermal absorption and emissivity. We expect methods for identifying errors and limits of various RT methods, and highlighting 3D effects characteristic of UV, Vis-NIR, and thermal RT. We strongly encourage papers on new approaches explicitly considering 3D radiative effects.

Organisers:  IAMAS (ICACGP)
Lead Convenor: Maria Kanakidou (Greece)
Co-convenors:  Kimitaka Kawamura (Japan), John Burrows (Germany)

Scope: This session aims to address recent research findings in the field of atmospheric chemistry and global pollution. It encompasses air pollution at various temporal and spatial scales and its impact on the biogeochemical cycling of species. Relevant foci include:

• the interaction between the earth surface and the lower atmosphere, including the measurements of trace constituent fluxes;
• long range transport and transportation of trace gases;
• the sources and sinks of greenhouse gases both long lived and short lived;
• ozone, aerosol and acidification;
• interactions of substances with natural and anthropogenic origin;
• impact of megacities on air pollution and biogeochemical cycles; and
• impact of natural emissions on megacities air pollution.

Presentations of results from recent field studies, involving satellite, aircraft and ground based instrumentation as well as laboratory investigations and modelling are welcome.

Organisers:  IAMAS (ICCP)
Lead Convenors: Andrew J. Heymsfield (United States of America), Paul J. DeMott (United States of America)

Scope: Measuring and predicting the formation and growth of ice particles in clouds and their potential relation to the changing state of atmospheric composition remain as enigmatic topics. Yet such knowledge and capabilities are critical to ultimately understanding and quantifying the role of aerosols and clouds in affecting weather and climate. Many approaches advance knowledge in this area including theoretical studies, experimental measurements (laboratory, ground-based, aircraft, satellite), cloud and climate model simulations, and combinations thereof. This session welcomes papers touching on all aspects of this study area including theoretical developments; laboratory measurements of ice nuclei,  ice nucleation mechanisms, and secondary ice formation processes; physical and chemical  identification of various types of atmospheric aerosols as primary ice nuclei; description of new techniques for measuring ice crystal and ice nuclei concentrations; field measurements providing insights into primary or secondary ice formation processes; direct or indirect comparisons of ice nuclei and ice formation in clouds; studies and parameterizations of aerosol-ice cloud and aerosol-mixed phase cloud interactions; measurements and parameterizations of ice particle growth; and modeling studies of ice formation and its implications at all model scales (parcel to global).

Organisers:  IAMAS (ICPM)
Lead Convenor: Tom Lachlan-Cope (United Kingdom)
Co-convenors:  Matthew Lazarra (United States of America)

Scope: Modern mesoscale and synoptic scale meteorology has arrived to the Arctic and Antarctic.  Developments in the last decade have been seen in observing and numerical modelling in these remote portions of the Earth. This combination has lead to better understanding of polar atmospheric phenomena and improved weather forecasting capabilities. This symposium aims to bring together studies of both synoptic scale and mesoscale meteorological phenomena in the Arctic and Antarctic. Studies using in situ or remote sensing observations as well as numerical studies or a combination are encouraged in this session. Sample topics areas include studies of polar low systems, high wind events, including katabatic winds, significant weather events, storm-track studies and data syntheses from reanalysis. While we are interested in soliciting papers from the polar meteorological community, we welcome submissions from other disciplines.  Observational, modelling and process studies are welcome.

Organisers: IAMAS (ICCP)
Lead Convenor: Jen-Ping Chen (ICCP)
Co-convenors:  Zifa Wang (China), Slobodan Nickovic (WMO)

Scope: Mineral dust particles in the atmosphere play important roles in processes of radiation, cloud microphysics, and heterogeneous chemistry.  Their emission is associated with storm activity, land use change, and climate variability; their transport is controlled by convections and large-scale circulations; their deposition involves turbulence and cloud processes, and is influential to marine and land ecosystems.  Projecting their impacts requires knowledge of size distribution, optical properties, and the state of mixing with other aerosol particles, and yet large uncertainties remain in such information.  This session solicits contributions that refine and place stronger constraints on our knowledge of the physical and chemical properties of mineral dust, as well as their emission, burden, and deposition.

Organisers:  IAMAS (ICMA), WCRP (SPARC), IGAC
Lead Convenor: Greg Bodeker (New Zealand)
Co-convenors: Murry Salby (Australia)

Scope: Stratospheric change has been most visible at high latitudes of the Southern Hemisphere, in association with the Antarctic ozone hole. Ozone depletion, along with changes of water vapor and other greenhouse gases, can introduce secondary changes in radiation, thermal structure, and dynamics. Through a complex interplay, these processes influence climate, not only in the stratosphere, but in the troposphere and at the Earth's surface. They have been suggested in relation to observed changes of surface climate in and around Antarctica, specifically, anomalous cooling over the Antarctic interior and warming around its periphery. Suggested likewise is increased Antarctic sea ice, possibly in association with increased surface wind stress and resulting changes of ocean transport. Stratospheric influence on climate is not limited to high latitudes of the Southern Hemisphere. It has been raised even in relation to the tropospheric Hadley circulation.

As the Antarctic ozone hole recovers over the coming decades, anomalous forcing of surface climate by ozone will reverse. Simultaneously, anomalous forcing by greenhouse gases will strengthen. Like their interaction with thermal structure and dynamics, the impact of these opposing changes on Southern Hemisphere climate is not well understood. These issues are central to the SPARC (Stratospheric Processes And their Role in Climate) core project of the World Climate Research Programme. This symposium invites contributions that throw light on these issues, especially in relation to climate changes over the Southern Hemisphere. Interdisciplinary studies that bridge historically-distinct areas are encouraged.

Organiser: IASPEI, IUGG, and Comprehensive Nuclear Test Ban Treaty Organization (CTBTO)
Co-sponsors: IAMAS, IAPSO
Principal Convenors: Ola Dahlman (Sweden), Zhongliang Wu (China)
Co-convenor: Andrew Forbes (United Kingdom), Lassina Zerbo (Burkina Faso), David Jepsen (Australia)

Scope: The global verification system of the Nuclear Test Ban Treaty (CTBT) relies more on cutting-edge science and technology than any other international arms control treaty. All components of the CTBT’s unique verification system – the International Monitoring System (IMS) with a global network of 337 monitoring facilities, the International Data Centre (IDC) for the analysis of large amounts of data, and an On-Site Inspection Regime (OSI) that utilizes a series of high-resolution technologies – are dependent on ongoing development of science and technology and a close relation to, and interaction with, the scientific community. The symposium will be focused on, but not limited to, the scientific topics of the CTBTO verification system (seismological, infrasound, hydro-acoustic and radionuclide monitoring; atmospheric transport modelling; and high-resolution geophysical and radionuclide surveys) and will include an overview of the verification system, its current status, and the underpinning sciences. Because the global verification system uses multiple technologies to detect seismo-acoustic events, which may be nuclear in origin, studies exploiting the synergy between sciences cross-cut the topics of several IUGG Associations. Contributions on the use of CTBT monitoring data to enhance sustainability (such as preparedness for and warning of natural hazards and the management of nuclear incidents) are welcome. New developments in geophysical science and technology and their implications for CTBT monitoring and the use of CTBT monitoring data in basic geophysical studies on the physics and chemistry of the Earth's interior are also issues of interest to this symposium.

The theme of the 2011 IUGG General Assembly is “Science for a Sustainable Planet”. Nuclear disarmament and non-proliferation are essential elements in creating a Sustainable Planet. Science and technology have been important to develop the verification regime of the Comprehensive Nuclear Test Ban Treaty (CTBT), the most extensive international verification system ever created. The purpose of this regime is to detect and locate nuclear explosions in the atmospheric, underwater and underground. The main challenge is to monitor underground tests and discriminate such tests from other artificial and/or natural events, in particular earthquakes.

The verification system is built on a number of sciences such as seismology, infrasound, hydro-acoustics, and radionuclide observations. Modelling and monitoring of atmospheric transportation play an important role in the tracing of radionuclides, which is crucial in identifying a nuclear test. To provide high quality data, observation systems have to be operated and maintained in a professional way, and their performance have to be monitored and evaluated. The application of new concepts, such as data fusion and data mining, are essential to analyse and to exploit a rapidly increasing amount of data. The International Monitoring System (IMS) and similar large scale observation systems established for scientific purposes are, in a way similar to accelerators in high-energy physics and satellites in space science, “big science device” providing not only experiences and lessons on monitoring practice, but also unique datasets of great value in basic research and in the application of science and technology for sustainability. New frontiers in modern geophysics, such as high-precision seismology, high-performance computation for atmosphere transport modelling, automatic processing of signals, and satellite remote sensing technology, as well as the newly developed “Digital Earth” technique, have provided the monitoring of CTBT with new opportunities and new challenges. Remarked by a series of important events, especially the Conference “CTBT 1996-2006: Synergies with Science and Beyond”, and the 2009 Conference “International Scientific Studies” (ISS09), a new era of cooperation between CTBT monitoring communities and scientific communities has started, which will contribute both to the CTBT monitoring practice and to the development of geophysical science.

To reflect the up-to-date advancements in this inter-disciplinary field, this Union symposium is focused on, but not limited to, geophysical studies of CTBT monitoring. Contributions from seismic, hydro-acoustic, infrasound, and radionuclide monitoring, data processing, data fusion and data mining, and system performance evaluation are welcome to the session, highlighting the implementation and synergy of different technologies for CTBT monitoring. Contributions on the use of CTBT monitoring data to enhance sustainability (such as the preparedness of natural hazards and the management of nuclear incidents) are also welcome. New developments of geophysical science and technology and its implication for CTBT monitoring and the using of CTBT monitoring data in basic geophysical studies on the physics and chemistry of the Earth’s interior are also issues of interest to this Union symposium. All contributions to the symposium are in the form of posters. Oral presentations are by invitation only.

Keywords: seismology, infrasound monitoring, hydro-acoustic monitoring, radio nuclide monitoring, atmospheric transport modelling, data mining, data analysis, sustainability.

Review: All contributed abstracts will be reviewed by the convenors.

Options: All contributed abstracts will be presented as posters. Only invited papers will be scheduled for oral presentations.

Organiser: IAMAS
Co-sponsors: IAHS, IAPSO, IASPEI
Principal Convenors: Michael MacCracken (United States of America), Alan Robock (United States of America)
Co-convenors: Larry Brown (United States of America), Ken Denman (Canada), Dave Jackson (United States of America), Dongxiao Zhang (China)

Scope: With the pace of climate change increasing and the array and magnitude of climate impacts intensifying, increasing attention is being paid to the potential for limiting the effects of anthropogenic climate change through large-scale geotechnical means, often called geoengineering. The most discussed approaches include deliberately altering the Earth's radiation balance and intervening in the carbon cycle or other biogeochemical cycles, for example via scrubbing carbon dioxide from the atmosphere. Although specific approaches have been proposed, relatively little is known about their potential effectiveness and possible unintended consequences. Issues of technological feasibility are also largely unexplored. The set of invited presentations will describe and address the potential effectiveness and scientific and technical problems associated with deliberate climate modification, including the potential for enhancement of terrestrial and oceanic carbon sinks. Presentations will cover modeling studies of the climatic impacts of proposed schemes for altering the absorption of solar radiation; studies of unintended environmental consequences; and evaluations of technological feasibility. Recognizing that geoengineering raises a range of environmental, societal, and governance issues, perspectives on how these complexities interface with proceeding with scientific research and potential deployment will also be offered.
This symposium is continued in greater depth in the Joint Symposium J-M01/J-V06 “Geoengineering: Can it limit climate change and its impacts?”

Keywords: geoengineering, climate intervention, global warming, carbon sequestration, solar
radiation management

Options: All papers in this symposium will be invited. Please contribute abstracts to the related Joint Symposium J-M01/J-V06 “Geoengineering: Can it limit climate change and its impacts?” which will have both oral and poster presentations.

Organiser: IAHS
Co-sponsors: IACS, IAG, IAMAS, IAPSO
Principal Convenor: Pierre Hubert (France)
Co-convenors: Andrea Flossman (France), Manfred Lange (Cyprus), John Pomeroy (Canada), Paul Tregoning (Australia), Susan Wijffels (Australia)

Scope: Based on the observation of the continuous movement of water, the idea of a hydrological cycle appeared in the most remote antiquity, but the corresponding scientific concept was coined only three centuries below by Pierre Perrault and Edmund Halley, based on their measurements and water balance computations. Today the hydrological cycle is well known and taught as soon as in primary schools. But do we really understand this extraordinarily complex system, which operates over huge time and space scales, involves the flow of liquid, solid and vapour phases of water and whose processes shape the face of the Earth by impacting biology, geochemistry, geophysics, climatology and redistributing matter and energy? We still have a lot to learn about the hydrological cycle. To take only a few examples: what is the uncertainty regarding the Earth’s water inventory, water phase and fluxes?  Do we really know what a cloud is and how it behaves?  Can we predict streamflow from physical first principles? Do we really know the paths of water on the continents, between precipitation and the continental reservoirs of surface, ground, snow and glacier water and the oceans? This symposium will be devoted to these gaps which jeopardize many scientific and practical activities such as water resources prediction and assessment and to the ways to overcome them. All contributions from geoscientists developed in an interdisciplinary spirit will be welcome.

Keywords: Hydrological cycle, water cycle, hydrosphere, atmosphere, cryosphere.

Review: All contributed abstracts will be reviewed by the convenors.

Options: All contributed abstracts will be presented as posters. Only invited papers will be scheduled for oral presentations.

Organiser: IAGA
Co-sponsors: IACS, IAG, IAMAS, IAPSO, IASPEI
Principal Convenors: Eigil Friis-Christensen (Denmark)
Co-Convenors: Ian Allison (Australia), Hugo Beltrami (Canada), Steven Nerem (United States of America), Gerassimos Papadopoulos (Greece), Denise Smythe-Wright (United Kingdom)

Scope: Climate change is a topic, which is on the top of the agenda, not only within the science community but also in the society at large. IUGG is a scientific organization, which covers many of the aspects of climate change including the causes, anthropogenic and natural, as well as the consequences. The purpose of this symposium is to demonstrate by invited speakers from various disciplines the complexity of the issue and the need for interdisciplinary initiatives in order to understand the science and the way it has an impacts on our society. IUGG is the primary scientific organizations to offer both the scientific expertise of the Associations and the overall perspective.

Keywords: climate dynamics, natural causes of climate change, anthropogenic causes of climate change.

Review: All contributed abstracts will be reviewed by the convenors.

Options: All contributed abstracts will be presented as posters. Only invited papers will be scheduled for oral presentations.

Organiser: IAGA – as part of IUGG Geoscience in Africa initiative and the eGY-Africa program.
Co-sponsors. IAG, IAHS, IAMAS, IAPSO, IASPEI, IAVCEI, African Geospace Society (AGS), Association of African Universities (AAU), Africa Earth Observing Network (AEON), AfricaArray; ICSU Regional Office for Africa, CODATA, International Network for the Availability of Scientific Publications (INASP), UN Global Alliance for Information and Communication Technologies and Development (UN-GAID), U.S. InterAcademy Panel on International Issues (IAP); European Enabling Grid for e-Science (EGEE); Geoscience Information in Africa (GIRAF); and the Abdus Salam International Centre for Theoretical Physics in Trieste (ICTP).
Principal Convenor: Charles Barton (Australia)
Co-convenors: Abdelkrim Aoudia (Algeria), Hussein A. Abd-Elmotaal (Egypt), Rabiu Babatunde (Nigeria), Harouna Karambiri (Burkina Faso), Christine Amory-Mazaudier (France), Laban Ogallo (Kenya), Bamol Sow (Senegal), Maarten de Wit (South Africa).

Scope: The session will cover a combination of both the leading Earth and space science being undertaken and planned in Africa in the areas covered by all eight Associations, and also infrastructure issues (such as efforts to create a better professional environment for African scientists, open access to publications, internet connectivity, support for African science, education, and training). The symposium will provide (i) a forum for presenting and discussing the latest African geoscientific research, (ii) a cross-disciplinary view of geoscientific activity in Africa (Africa being the focus of the symposium), (iii) a stimulus for stronger interest and participation in African science by African and non-African scientists, and (iv) an opportunity to explore progress in creating a better professional working environment for people engaged in scientific research, education, and training in Africa.

Keywords: geoscience in Africa, integrated African research, unique African geoscience, research and education infrastructure, Internet connectivity, research and education networks, open access to publications, professional geoscientific bodies.

Review: All contributed abstracts will be reviewed by the convenors.

Options: All contributed abstracts may be presented as posters. The convenors will invite selected papers for oral presentations.

Organiser: IUGG
Co-sponsors: IACS, IAG, IAGA, IAHS, IAMAS, IAPSO, IASPEI, and IAVCEI
Principal Convenors: Harsh Gupta (India) and László Szarka (Hungary)

Scope: With the passage of time, the importance of "Geophysics" as a discipline is increasing. A large number of young persons are joining the Geophysics stream. IUGG is conscious of the aspirations of young geophysicists. This Union Symposium would have speakers, preferably 35 years old or younger, from the 8 Associations of IUGG and a few other invited young persons to share their experience, expectations, successes and concerns in development of Geophysics.

This symposium is under active development.

Organiser: IAGA, ICMA, IAMAS
Lead Convenor: Susan Avery (United States of America) 
Co-convenor: Alan Rodger (United Kingdom)

Scope: CAWSES-II is an international interdisciplinary programme that addresses fundamental questions of how the coupled sun-earth system operates on timescales of minutes to millennia.   Key questions include: (i) What are the solar influences on the Earth’s climate? (ii) How does the short term solar variability affect geospace?  (iii) How does short-term solar variability affect the gespace environment? (iv) What is the geospace response to variable waves from the lower atmosphere?  Such questions require coordinated inter-disciplinary, international effort.  The symposium will not only cover scientific breakthroughs in this area that use systems approaches but will also include examples of novel scientific and technical infra-structure that facilitate novel ways of carrying out system science.

Keywords: sun-earth system, solar variability, geospace, waves from lower atmosphere

Organiser: IAGA, ICMA, IAMAS
Lead Convenor: Gufran Beig (India)
Co-Convenor: Jan Lastovicka (Czech Republic)
 
Scope: Human activities pollute the atmosphere, which results among others in increasing concentration of greenhouse gases in the atmosphere and depletion of ozone layer. Past two decades have enriched us with a plenty of observational and model results on related changes in the middle and upper atmosphere including the ionosphere. The primary goal of this symposium is to present recent observational as well as model simulation progress in the field of long-term changes and trends in the ionosphere, thermosphere, mesosphere and stratosphere. The relative importance of natural and anthropogenic influences on long-term trends and their changing role with time will be addressed. Both observational and model simulation contributions are welcome.

Keywords: greenhouse gases, natural and anthropogenic influences, depletion of ozone

Organiser: IACS
Co-sponsors: IAMAS, IAPSO
Lead Convenors: Scott Elliot (United States of America), Andrew Roberts (United States of America)
Co-Convenors: Ralf Döscher (Sweden), Annette Rinke (Germany)

Scope:  This session will focus on model development and results that seek to explain physical-biogeochemical-ecological-human interconnectivity within the arctic environment.  Model developments and results presented at this session will typically relate to the use or evaluation of coupled regional arctic sea ice-ocean-atmosphere climate models with coupled 'system' components, such as sophisticated biogeochemistry, hydrology, marine and terrestrial ecosystems, atmospheric chemistry and aerosols, ice-sheets and human-system components.

Keywords: Arctic, regional models, ice-ocean-atmosphere climate models, earth system modelling

Review: All contributed abstracts will be reviewed by the Convenors

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors.
Please note also 'J-P02 Future State of the Arctic and Potential Impact"

Organiser: IACS
Co-sponsors: IAMAS, IAHS(ICSIH)
Lead Convenors: Michael Lehning (Switzerland), Marc Parlange (Switzerland), Pierre Etchevers (France), Eric Brun (France)
Co-Convenors: Samuel Morin (France)

Scope:  Mass balance of Alpine glaciers, snow water storage in the mountains providing water to arid areas and local microclimate are only a few examples why snow – atmosphere interactions in mountains need to be understood. Snow deposition in mountains is governed by precipitation gradients across mountain ranges, preferential deposition caused by local flow – precipitation interactions and redistribution of snow via saltation and suspension. Snow ablation depends heavily on the local energy balance with spatially varying radiation and turbulent fluxes. In complex terrain, shortwave radiation varies because of shadowing and reflections, longwave radiation varies because of varying emissions from snow, rock, soil or vegetation and turbulent fluxes vary because of differences in surface properties as well as varying wind speeds. Inversely, the presence or partial presence of a snow cover alters the forcing of the land surface on the atmosphere. In order to answer the question “how much snow is there on the mountain, where, when and why” and to make assessments of current and future snow cover, these interactions need to be understood quantitatively. This session invites contributions on the subject from atmospheric scientists, hydrologists and snow scientists.

Keywords: snow, atmosphere, energy balance, mass balance,  mountain regions

Review: All contributed abstracts will be reviewed by the Convenors.

Options: Accepted abstracts will be presented as either oral or posters as determined by the convenors. Tentative list of invited speakers

Organiser: IAG
Co-sponsor: IAMAS
Lead Convenor: Marcelo Santos (Canada)
Co-Convenors: Olivier Bock (France), Jens Wickert (Germany)

Scope: Eminently space geodetic techniques such as Very Long Baseline Interferometry (VLBI), Doppler Orbitography by Radio positioning Integrated by Satellite (DORIS) and Global Navigation Satellite Systems (GNSS) – like the Global Positioning System (GPS), the Russian GLONASS and others under development (e.g., Galileo), have become a powerful tool for meteorology. In its basics, atmospheric remote sensing takes advantage of the bending radio waves suffer while propagating through the atmosphere. Derived atmospheric parameters are, e.g., water vapour and temperature distributions on regional or global scales. Dedicated regional and global ground networks and satellite-based GPS missions, such as COSMIC/FORMOSAT-3 and Metop, have contributed already to global operational meteorological data bases, helping to improve weather forecasts and enabling climate change related investigations. On the other hand, geodetic positioning can significantly benefit from meteorology by using data available via Numerical Weather Prediction (NWP) models to improve the correction of troposphere-induced errors that affect the space geodetic techniques.

The symposium will explore the characterized synergistic link offered by space geodesy-based atmospheric remote sensing towards atmospheric correction for Geodesy and remote sensing applications for Meteorology/Climatology and atmospheric research. It focuses on the application of ground and satellite based GNSS neutral-atmosphere sounding and other space geodetic techniques for meteorology and on the development of novel GNSS based remote sensing techniques, as, e.g., reflectometry/scatterometry. Additional aspects are: advancements in modelling the troposphere using GNSS and NWP (e.g., water vapour fields using GPS tomography), assimilation of atmospheric GPS data products into meteorological models, modelling of propagation error sources, geodetic observation instrumentation, current and future GNSS atmospheric remote sensing satellite missions, and applications in  precise geodetic positioning. We encourage the submission of papers dealing with methodology, applications, as well as with inter-comparisons and validation.

Keywords: atmosphere, troposphere, remote sensing, water vapour, temperature, GNSS, VLBI, COSMIC

Review: All contributed abstracts will be reviewed by the Convenors

Options: Contributed papers are optionally oral or poster presentations

Organiser: IAG
Co-sponsors: IACS, IAGA, IAHS, IAMAS, IAPSO, IASPEI, IAVCEI, IOC, GOOS, GCOS, GEO/GEOSS
Lead Convenor: Markus Rothacher (Switzerland)
Co-convenors: Ruth Neilan (United States of America), Mioara Mandea (France), Keith Alverson (France), Massimo Cocco (Italy)

Scope: Earth observations are the fundamental basis for most IUGG scientific research, activities, and applications. Integrating these observations is of increasing importance to better understand our planet Earth and the challenges we face now and in the coming decades. These observations are of vital importance for virtually all associations working under the auspices of IUGG and inter-association, even inter-Union activities are being further developed or initiated.  Entities like the Global Ocean Observing System (GOOS), the Global Terrestrial Observing System (GTOS), and the Global Climate Observing System (GCOS), along with the Global Geodetic Observing System (GGOS), demonstrate the need for highly collaborative international observations that target key questions, and the systems necessary to integrate them for multi-disciplinary applications and decision-making. The importance of developing global observing strategies is recognized by GEO, the Group on Earth Observations, with its main aim to develop the GEOSS (Global Earth Observation System of Systems), which is supported on the government level by about more than 80 countries. This symposium shall give an overview of the major international developments towards integrating Earth observations, Inter-Union activities of the International Council for Science (ICSU), and developments within the IUGG associations.

Keywords: earth observations, monitoring systems

Review: All contributed abstracts will be reviewed by the Convenors

Options: Contributed papers are optionally oral or poster presentations

Organiser: IAHS (ICRS, ICSW, ICGW, ICWRS, PUB, GRACE), IAG, IAMAS
Lead Convenor: Mohsin Hafeez (Australia)
Co-Convenors: Makoto Taniguchi (Japan), Earl Bardsley (New Zealand), Roland Pail (Germany), Frederique Seyler (France), Nick van de Giesen (The Netherlands)

Scope: This session focuses on the recent advances in GRACE, other remote sensing platforms, and ground based methods for estimating spatial/temporal surface water balance, spatially averaged water budgets, hydrodynamics, hydrological processes, and characterization of ground water system in gauged and un-gauged basins at regional and global terrestrial scales.

New satellites, such as GRACE, SMOS, and METOP, are starting to generate hydrological parameters that have large potential for water managers in data sparse environments. Sensors as radar altimeters, primarily designed for ocean or ice studies, are now used for monitoring continental waters. Optical-thermal satellite based evapotranspiration measurement techniques have been extensively used for water accounting from farm to irrigated catchments over the past decade. Another example is the recently developed modelling technique using GRACE satellite provides estimates of terrestrial water storage and their temporal changes. Finally, the “Predictions in Ungauged Basins” initiative (PUB) could focus on remote sensing models and estimates of spatially-averaged water budget components across scales and beyond catchment boundaries. In parallel, advances in ground-based measurement techniques, such as distributed temperature sensing, geological weighing lysimeters (gwl), and geophysical surveys are finding their way into research and practice for characterizing the hydrological parameters by more efficient means.

This symposium seeks to bring together specialists from different disciplines to produce a review of the state-of-the-art of direct and indirect physical measurement techniques for water resources management over the full range of terrestrial spatial scales from pixel to continent. Papers are invited on the estimation, validation, and error/uncertainty assessment of hydrological parameters such as actual evaporation, soil moisture, recharge, seepage, percolation, and runoff in farms, irrigated/dryland systems, and gauged/un-gauged catchments at multi temporal scales.

Organiser: IAHS (ICCLAS, ICSW, HYDROMET), IAMAS
Lead Convenor: Stewart Franks (Australia)
Co-Convenors: Eleanor Blyth (United Kingdom), Eva Boegh (Denmark), Koray Yilmaz (United States of America), David Hannah (United Kingdom)

Scope: The interaction between the land surface and the atmosphere is fundamental to understanding the nature of hydro-climatic variability and change. Despite this, many future climate scenarios for assessing future hydrological and climatological change are weak in terms of the role of and impacts on evaporative and sensible heat fluxes, soil moisture, maximum temperatures and hence future hydrologic regimes are largely uncertain. In this symposium, we aim to provide a comprehensive review of studies and methodologies for assessing future land surface hydrologic regimes. In particular, we seek contributions to this symposium on the following suggested themes:

• Measurement and estimation of land surface fluxes
• Integrated remote sensing of evapotranspiration within modelling studies
• Use of empirical models of evapotranspiration
• Methods for estimating future land surface fluxes under a changing climate
• Trends in hydro-meteorological/climatological variables
• Change Detection/Attribution studies using hydro-meteorological records
• Changing land surface fluxes under natural modes of variability
• Extreme events

Organisers: IAHS (ICSW, ICWRS), IAMAS, WMO, BOM Australia
Lead Convenor: Bruce Stewart (Australia)
Co-convenors: Gabriel Arduino (WMO), Hege Hisdal (Norway)

Scope: Settling on flood plains has enormous advantages, as is evident from the very high densities of human settlement in, for example, the Netherlands and Bangladesh. Disaster mitigation approaches that restrict the occupation of flood plains and wetlands can limit the potential of these lands for socio-economic development. The balanced management of floodplain areas is thus important element to flood management. Integrated Flood Management (IFM) integrates land and water resources development in a river basin, within the context of Integrated Water Resources Management (IWRM), with a view to maximizing the efficient use of flood plains and minimizing loss to life. Thus, occasional flood losses can be accepted in favour of a long-term increase in the efficient use of flood plains. End-to-end IFM initiatives will require combinations of flood management practices including structural and non-structural approaches working in harmony with flood plain development activities. This session will focus on Integrated Flood Management in general and in particular advances in flood forecasting and warning capabilities.

Organisers: IAHS (ICSIH, ICLAS, ICRS, ICGW, ICSW, PUB), IAMAS, IACS
Lead Convenor: Danny Marks (United States of America)
Co-Convenors: Michael Lehning (Switzerland), David Collins (United Kingdom), Mark Seyfried (United States of America), Regine Hock (Sweden), John Pomeroy (Canada), Marc Parlange (Switzerland)

Scope: Changes in storage of water as seasonal snowpack, frozen ground, and perennial snow and glacier ice, and release of meltwater are major components of hydrological systems in the high mountain regions of the world. In such areas, the annual cycle of meltwater production from snow and ice is critical, influencing streamflow regime, soil moisture, and both terrestrial and aquatic ecosystems. Meltwater availability is crucial in cold mountain environments and in areas downstream, for agriculture and hydropower, particularly where the areas surrounding mountains are otherwise arid and susceptible to drought. Mountain snowpack, permafrost, glaciers and meltwater runoff will continue to be influenced strongly by climate change into the future. Detailed understanding of and the ability accurately to model inter-relationships between climate, snowpack, ground ice and glacier dynamics coupled with intra-basin hydrological processes are necessary in order to test hypotheses concerning contemporary and future interactions between high mountain climate, snow, ice, runoff, biogeochemistry and water quality. This symposium addresses a broad range of topics important for better understanding of snow and ice hydrology in mountain regions and for reducing uncertainty and increasing physical realism in modelling and prediction under climate change. Contributions on the following topics are particularly welcome: measurement and monitoring techniques for snow and ice in cold mountainous regions; physical properties of snow, permafrost and ice – parameterisation of microscale properties for macroscale prediction; using remote sensing for improvement of prediction of runoff from snow and ice in data-sparse mountain areas; forecasting meltwater runoff from ungauged high mountain basins; assessment of risk and prediction of glacier lake outburst floods in mountain areas, and impacts of mountain snow and ice hydrology on water resources in drier downstream areas in a changing climate.

Organiser: IAPSO
Co-sponsor: IACS and IAMAS
Lead Convenor: Bruno Tremblay (Canada)
Co-Convenors: Göran Björk (Sweden), Claude Duguay (Canada), John Turner (United Kingdom), John Cassano (United States of America)

Scope: The Arctic has witnessed large changes in recent years. Of these changes probably the best documented is the decline of its sea ice cover particularly apparent at the end of the summer melt season. Other changes include the river runoff, surface air temperature, sea level pressure, storminess, etc. In the future, GCMs also simulate sharp decline in the sea ice cover leading to a practically ice free Arctic in the late summer and early fall. This new state of the system may lead to drastically different ocean-atmosphere heat and moisture fluxes and associated circulation changes in the atmosphere and ocean. In this session we welcome contributions that address resent observed changes in the Arctic climate system and strive to characterize a possible new state of the atmosphere/ice/ocean system including the potential effect on the biosphere.
Note also "J-C01 Arctic System Modelling"

Keywords: Arctic Ocean, Ice cover, Arctic climate system, decline of sea ice, ice-free Arctic

Review: All contributed abstracts will be reviewed by the Convenors.

Organiser: IAVCEI
Co-sponsor: IAMAS
Lead Convenors: Andrew Tupper (Australia), Peter Webley (United States of America), Warner Marzocchi (Italy), John Nielson-Gammon (United States of America)

Scope: Volcano observatories charged with protecting life and property are often under intense pressure during a volcanic crisis.  The globalisation of the world’s media and increased awareness of volcanic hazards to the aviation industry and to general human health, as well as volcanic effects on climate, puts additional pressure on scientists and disaster managers at the source. Conversely, observations from the wider world, including from the world’s aerosol, seismic, aviation and other communities, might usefully feed back to the source to help understand an eruption in the context of its world significance.  International science efforts can also, if appropriately coordinated, significantly enhance the capacity of local scientists and disaster managers. This symposium invites case-studies about the relationship between the scientists at the volcanic source and science in the wider world.  In what ways can scientists support both local disaster mitigation and good international science? What new technologies can be applied, what observations from the source are the international community needing, and how do we help each other?

Keynote speakers: Ima Itikarai

Organiser: IAVCEI
Co-sponsor: IAMAS [ICCL]
Lead Convenors: Michael MacCracken (United States of America), Alan Robock (United States of America)

Scope: With the pace of climate change increasing and the array and magnitude of climate impacts intensifying, increasing attention is being paid to the potential for limiting the effects of anthropogenic climate change through large-scale technical means, often called geoengineering. Possible approaches include deliberately altering Earth's radiation balance, and intervening in the carbon cycle or other biogeochemical cycles, for example via carbon scrubbing and sequestration. Although specific approaches have been proposed, relatively little is known about their potential effectiveness for moderating climate change and possible unintended consequences. Issues of technological feasibility are also largely unexplored. Papers are invited that describe and address the potential effectiveness and scientific and technical problems associated with deliberate climate modification, including enhancement of terrestrial and oceanic carbon sinks. Possible examples include modeling studies of the climatic impacts of proposed schemes for altering the absorption of solar radiation; studies of unintended environmental consequences; and evaluations of technological feasibility issues. Papers on historical, ethical, and governance issues are welcome.  As volcanic eruptions have been suggested as a natural analog for stratospheric geoengineering, papers studying the effects of explosive volcanic eruptions on climate are also welcome.
This joint symposium is also listed by IAMAS as J-M01 and is closely linked to and follows on from the Union symposium U-06 “Geoengineering: What are the Potentials for Climate Intervention, Carbon Scrubbing, and other Approaches to Moderate Climate Change and its Impacts?”

Organiser: IAVCEI
Co-sponsor: IAMAS
Lead Convenors: Fred Prata (Norway), Andrew Tupper (Australia), Simon Carn (United States of America)

Scope: Volcanic ash is recognized as a significant hazard to aviation.  Its global reach, the sporadic nature of volcanic eruptions and the potential impact of ash on global aviation presents a high risk and high economic impact.  The recent highly publicized Eyjafjallajoekull eruption in Iceland has clearly demonstrated the widespread societal and economic impact of volcanic ash, when it affects aviation.  The purpose of this Symposium is to bring together experts on the problem of volcanic ash as a hazard to aviation.  The primary focus will be on remote sensing techniques applied to volcanic clouds and plumes, but we welcome contributions on other aspects of the problem, including atmospheric dispersion modelling, warning systems, ground-based, airborne, and in situ measurements, aviation aspects, societal and economic impacts and new methods for helping to avoid and mitigate the risk to aviation.  The growth of air traffic in SE Asia and over the Pacific together with the large number of potentially hazardous volcanoes within the Pacific Rim, make this region particularly vulnerable.  Thus submission of research work with an emphasis on the Pacific Rim or SE Asia are strongly encouraged.

Keynote speakers: Tom Casadevall, Andreas Stohl