M01 Middle Atmosphere Symposium

Convener(s): Bernd Funke (Spain), Natalia Calvo (Spain)

Co-Convener(s): Amy Butler (USA), Seok-Woo Son (South Korea), Christian von Savigny (Germany), Irina Mironova (Russia)

Description
The Middle Atmosphere Symposium covers all aspects of middle atmospheric science, with emphasis on the interaction between dynamics, radiation and chemistry within the middle atmosphere itself and between the middle atmosphere and the troposphere. Observational, modelling, theoretical, and laboratory studies are all solicited. Research topics include (but are not limited to): - Gravity waves, their generation, propagation and breaking - Sub-seasonal to decadal dynamical variability in the middle atmosphere - Middle atmosphere response to anthropogenic and natural forcings - Stratospheric/mesospheric chemistry and ozone - Radiation, microphysics, chemistry and dynamics at the tropopause - Transport and mixing in multiple spatial scales - Tropical / extratropical dynamical interactions - Vertical coupling in the Middle Atmosphere - Mechanisms of stratosphere-troposphere coupling, at all time scales



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M02 Dynamics and Variability of the Warming Hole(s) in the Climate System

Convener(s): Léon Chafik (Sweden)

Co-Convener(s): Mojib Latif (Germany)

Description
The term ‘warming hole’ has become a buzzword in the literature. A warming hole often refers to a region, over ocean, land or sea-ice, that is cooling as compared to its surrounding. For example, the warming hole in the North Atlantic Ocean has attracted a lot focus in the past years due to its possible link to the suggested long-term slowdown of the Atlantic Meridional Overturning Circulation or AMOC. Over the US, a warming hole has been observed and linked to the Interdecadal Pacific Oscillation, although the transition of the latter in the late 1990s has been reported to have led to its disappearance. In the Pacific side of the Arctic, a warming hole has appeared and linkages to stronger meandering of the atmospheric jet have been discussed. In the Pacific sector of the Southern Ocean, unusual surface cooling as compared to the rest of the globe has been going on for three decades and increased sea-ice is put forward as one factor for this Antarctic warming hole. Overall, what these warming holes have in common is that they have competing explanations involving both oceanic, atmospheric and sea-ice processes, especially that of the North Atlantic because of its profound impact on global climate. The aim of this session is thus to learn more about the multiple drivers controlling these warming holes.



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M03 Climate Extremes in the Atmosphere-Land-Ocean System: Physical Processes, Predictability, Impacts and Adaptation

Convener(s): Jules Kajtar (Australia)

Co-Convener(s): Nicolas Freychet (UK), Eunice Lo (UK), Vikki Thompson (UK), Mat Collins (UK), Neil Holbrook (Australia)

Description
As the mean climate shifts and evolves due to anthropogenic greenhouse gas forcing, so too are the frequency, intensity, and duration of climate extremes continuing to change. Climate extremes, such as atmospheric heatwaves, marine heatwaves, storms, floods, and droughts, are increasingly impacting ecosystems and human infrastructure. There is a pressing need to further develop understanding of their physical processes, predictability, impacts, and how we might adapt to continued or increased occurrences in future. This session invites submissions exploring climate extremes in the atmosphere, ocean, or over land. Process or impact focussed studies of climate extremes are encouraged, including those that examine: the mechanisms by which they develop, persist, or decay; the timescales and conditions under which they are predictable; their impacts on eco- or human systems; and pathways to adaptability or mitigation. Studies into the characterisation or impacts of compound events are particularly welcome.



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M04 Past Climate Changes and Their Relevance for the Future

Convener(s): Qiuzhen Yin (Belgium)

Co-Convener(s): André Paul (Germany), Anne de Vernal (Canada), Jerry McManus (USA), Emilie Capron (Denmark), Ayako Abe-Ouchi (Japan)

Description
Paleoclimate research provides information on climate dynamics through time based on proxy reconstructions or model simulations of physical, chemical, and biological characteristics of the Earth climate system. Understanding the nature and mechanisms of past climate changes and the rates of changes in general, particularly of the past warm periods, has the potential to provide context and insight into climate and sea-level response to human activities over the industrial period and into the future, as well as the impacts of such climate change on the environment. This symposium invites researchers who investigate the long-term behavior of the climate system and of the environment in the past, its underlying processes, and how it is projected to change in the future. We encourage researchers who focus on different aspects of the climate system using various approaches (proxy records, climate models, inverse methods, machine learning, …) to participate.

Solicited speakers: Maria Fernanda Sanchez Goñi (Ecole Pratique des Hautes Etudes, France), Zhongshi Zhang (China University of Geosciences, China), Geritt Lohmann (Alfred Wegener Institute, Germany)

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M05 Atmosphere-Ocean-Ice Interactions: Physical, Biogeochemical and Biological Processes in the Ross Sea

Convener(s): Zhaomin Wang (China)

Co-Convener(s): Walker Smith (USA), Paola Rivaro (Italy), Jisoo Park (South Korea), Mike Williams (New Zealand)

Description
The Ross Sea is the site of the largest marine protected area in the ocean. Intense atmosphere-ocean-ice interactions in the Ross Sea produce the most saline dense shelf waters around the Antarctic, supplying the lower limb of the global overturning circulation. These processes transport anthropogenic carbon to the abyssal, an important component of the global carbon cycle. During the past decades, the freshening in the Ross Sea contributed to a decrease in Antarctic Bottom Water formation. The recent recovery of the bottom water formation in the Ross Sea has become a new research focus. The physical and biogeochemical processes strongly influence the marine ecosystem in the Ross Sea. Primary productivity on the continental shelf is greater than anywhere in the Southern Ocean, and this productivity supports massive accumulations of higher trophic levels and large deposits of biogenic material. Despite our understanding of numerous biological processes that occur in the Ross Sea, substantial uncertainties remain concerning energy and material transfer within the food web. In this session, we wish to focus on the complex physical, biogeochemical and biological processes to understand the drivers of the trends and variability in the Ross Sea. Contributions are invited on observational, theoretical and modeling studies concerning the physical, biogeochemical, and biological processes in the Ross Sea. Contributions on processes in other Antarctic marginal seas will also be considered. The suggested topics include: i) internal oceanic processes, including tides, waves, and eddies, and their roles in dense shelf water formation, transport and transformation; ii) atmospheric, sea ice and ice shelf processes, including, but not limited to, strong wind events, coastal polynyas, and mixing between dense shelf water and ice shelf water; iii) the air-sea carbon flux, carbon transport, and associated acidification; iv) biological and biogeochemical processes, including the role of iron, interannual variations, transfer of organic matter within the food web, and ecological interactions among all trophic level



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M06 Monsoon Systems in Rapid and Intensifying Climate Change and Their Role in Extreme Events

Convener(s): Jianping Li (China), V. Krishnamurthy (USA), Andrew Turner (UK)

Co-Convener(s): Bin Wang (USA), E. Hugo Berbery (USA), Jun Matsumoto (Japan), Kyun-Ja Ha (South Korea), R. Krishnan (India), Fred Kucharski (Italy)

Description
Monsoon systems in widespread, rapid, and intensifying climate change have experienced some major changes, which are intensifying the water end energy cycles and have profound impacts on extreme weather and climate events. These changes are affecting precipitation patterns, strength and variabilities, and cause more intense floods and drought as well, with significant social consequences. A better understanding of variability, dynamics and physics of monsoon systems in rapid and intensifying climate change and their role in Earth's energy budget and water cycle and extreme weather and climate events so as to better improve prediction and projection of monsoon systems is therefore of a great importance. This symposium invites presentations on all aspects of monsoon system studies, including observational, diagnostic, theoretical, attribution, modelling, prediction and projection researches.



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M07 Earth System Response to Solar Radiation Modification: Modeling, Impacts and Uncertainties

Convener(s): Govindasamy Bala (India), Hauke Schmidt (Germany)

Co-Convener(s): Long Cao (China), Simone Tilmes (USA), John Moore (China, Finland), Michael MacCracken (USA)

Description
To achieve temperature stabilization goals set by the Paris Agreement requires substantial reduction in greenhouse emissions and even net negative CO2 emissions, which is a grand challenge for the human society. Solar radiation modification (SRM), a class of climate intervention options that aims to cool the Earth by deflecting some more sunlight back to space, has attracted growing interest. Enhancement of the burden of reflective aerosols in the stratosphere, increasing the reflectivity of marine clouds by injecting cloud condensation nuclei and painting the urban roofs white are some examples. SRM research is still at an early stage, in particular with regard to efficiency, impacts and uncertainties of the different proposals. This session welcomes contributions to all aspects of SRM research, including modeling study of climate and Earth system response to various forms of SRM, benefits and side effects of different SRM approaches from local to global scales, and uncertainties underlying climate processes, geophysical response and ecosystem and societal impact of SRM. We also welcome studies on the engineering aspects of different SRM schemes and international governance of SRM.



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M08 Variability and Near-Term Predictability of the Antarctic Climate System

Convener(s): Tom Bracegirdle (UK), Zhaomin Wang (China)

Co-Convener(s): Irina Gorodetskaya (Portugal), Erik Behrens (New Zealand)

Description
In recent years and decades the Antarctic climate system (atmosphere, ocean, ice) has seen remarkable changes in association with both external forcings and internally-generated climate variability. An improved understanding of these recent changes is an important part of gaining confidence in estimates of how the system may change in the near term (on annual to multi-decadal timescales). The session will address the emergence of externally forced change in observations and climate models for which it is important to consider contributions from a range of drivers such as tropical teleconnections, internal Southern Ocean processes, and stratospheric ozone changes. Climate model evaluation against observations and improvements in design are highly relevant with regard to improving predictions and projections of future change. We welcome abstracts addressing related questions involving model results and observational datasets across a range of components of the Antarctic climate system. Priority topics include: extreme events and their contribution to underlying climate trends; explaining recent trends in sea ice and how it may evolve into the future; atmospheric circulation response to opposing responses to stratospheric ozone recover and GHG increases; and implications of current and future change for the rest of the planet. The session is supported by the SCAR Scientific Research Programme AntClimNow - Near-term Variability and Prediction of the Antarctic Climate system.



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M09 Geosciences for Sustainable Development (Merged with Union Symposium)

Convener(s): Keith Alverson (Canada)

Co-Convener(s): Tom Beer (Australia), Jianping Li (China), Tonie van Dam (Luxenburg)

Description
The International Year of Basic Sciences for Sustainable Development 2022 (IYBSSD 2022) will focus on links between basic sciences and the 17 Sustainable Development Goals (SDGs). This session will bring together contributions from all of the IUGG subsidiary disciplines highlighting how Earth Science understanding, monitoring and modeling contribute to sustainability both globally, in response to planetary pressures, as well as locally, in response to specific localized developmental constraints.



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M10 El Niño/Southern Oscillation and its Regional and Global Impacts

Convener(s): Fei-Fei Jin (USA)

Co-Convener(s): Wenju Cai (Australia), Jianping Li (China), Soon-Il An (South Korea)

Description
The El Niño – Southern Oscillation (ENSO), one of the most important drivers on climate variability, has profound climatic, environmental, economical, and societal impacts on both global and regional climate. Evidences, albeit limited, suggest that the basic characteristics of ENSO, including its types, amplitude, frequency, asymmetry, teleconnections etc., have been undergoing changes. However, projections for potential future changes are diverse and the whole issue of how ENSO may respond to global warming and thus contribute to the global and regional climatic and environmental changes is far from understood and is an important subject of intense research worldwide. This symposium invites contributions regarding the latest scientific advances on observational, theoretical and modeling studies on: ENSO dynamics, ENSO impacts, ENSO predictability and prediction, and ENSO projected changes and the associated impacts due to projected climate change scenarios.



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M11 Earth’s Energy Budget

Convener(s): Siji Kato (Unite States)

Co-Convener(s): Norman Loeb (USA), Martin Wild (Switzerland), Maria Hakuba (USA)

Description
The solar and infrared radiant energy within the Earth-atmosphere system and the exchange of turbulent heat fluxes between the surface and atmosphere are the dominant forms of energy that determine Earth’s climate. How these are distributed regionally dictates atmospheric and oceanic transport and precipitation patterns. This symposium seeks presentations that provide novel new insights into how energy is distributed within the climate system and how and why it is changing. We welcome both observational and modelling studies that encompass the following areas related to Earth’s energy budget: Earth’s energy imbalance and ocean heat storage; the linkages between the energy and water cycles; studies discussing how the energy budget is altered through forcing and feedback mechanisms.



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M12 Advances in Atmospheric Radiation

Convener(s): Peter Pilewskie (Unite States)

Co-Convener(s): Manfred Wendisch (Germany), Hajime Okamoto (Japan)

Description
Radiation sciences have proved essential for understanding energy processes and associated balance – and imbalance – within the Earth-Atmosphere system, providing fundamental knowledge of the radiative processes in the climate system and on global observation of climate parameters. Recognizing the importance of the radiation sciences, the International Radiation Commission (IRC) is concerned with research and application topics such as spectroscopic nature of atmospheric constituents and of the Earth's surface, radiant energy transfer theory and modeling, aspects of radiant energy in climate change and weather, remote sensing of the atmosphere and surface, and observations of radiant energy flow throughout the Earth-atmosphere system. Papers being solicited may include current progress in all of these research areas. In addition, it is encouraged that up-to-date progress in IRC Working Groups (Atmospheric Spectroscopy Applications, Baseline Surface Radiation Network, Clouds and Radiation, Continuous Inter-comparison of Radiation Codes, GEWEX Radiation Panel, Global Energy Balance, International Coordination group for Laser Atmospheric Studies, International Polarized Radiative Transfer, International TOVS Working Group, Solar Ultra Violet Radiation, Three-Dimensional Radiative Transfer) is presented in this symposium.



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M13 The Year of Polar Prediction (YOPP).

Convener(s): Amelie Kirchgaessner (UK), Irina Gorodetskaya (Portugal)

Co-Convener(s): James Doyle (USA)

Description
The climate system in the Polar Regions has changed rapidly over recent decades, and all components of the polar climate system are predicted to continue to change dramatically in the foreseeable future due to anthropogenic climate change. At the same time increased transportation and economic activities in the polar regions lead to growing demand for improved weather and climate information for the area. Significant improvement in environmental prediction capabilities for the polar regions and beyond is required to meet these demands. The Year of Polar Prediction (YOPP) is the flagship activity of Polar Prediction Project (PPP) providing a period of coordinated intensive observing, modelling, verification, user-engagement and education activities. For this session we invite all contributions from the Year of Polar Prediction, but would particularly invite reports and results from the second YOPP SOP in the Southern Hemisphere.

Solicited speakers: Gunilla Svensson (Stockholm University, Sweden), François Massonnet (UC Louvain, Belgium), Machiel Lamers (Wageningen University, Netherlands)

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M14 Climate Change in the Polar Regions

Convener(s): Dave Reusch (USA)

Co-Convener(s): Petteri Uotila (Finland)

Description
Over recent decades the polar regions have experienced some of the most profound climatic changes on Earth, with a marked decrease in the extent of Arctic sea ice, large regional surface warming, the loss of snow cover, disintegration of ice shelves, mass loss from the major ice sheets and the large anthropogenic changes as a result of the Antarctic ‘ozone hole’. This session will focus on Arctic and Antarctic climate change over the last century and possible change over the coming decades in a world of increasing greenhouse gas concentrations and recovery of the ‘ozone hole’. We welcome presentations on changes observed in the in-situ observations from high latitudes, Arctic and Antarctic sea ice, modelling the climates of the polar regions, high latitude modes of climate variability, oceanographic changes and the impact of tropical climate variability at high latitude.



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M15 Polar Modelling

Convener(s): John Cassano (USA), Annette Rinke (Germany)

Co-Convener(s): Andrew Orr (UK)

Description
The climate of the Polar regions has experienced significant changes over recent decades. Regional information on variability and change of the Polar climate is urgently needed but often deemed unreliable. The Polar CORDEX (COordinated Regional Downscaling EXperiment) project was initiated to develop regional climate downscaling of both the Arctic and the Antarctic to provide an accurate description of regional-to-local scale climate phenomena and their variability and changes. We encourage submissions that advance understanding of the processes that control polar climate variability in regional climate models. We also encourage submissions that examine model evaluation, coupled modelling, projections, and impact studies. This symposium also aims to promote stakeholder/user engagement.



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M16 Atmosphere-Ocean-Sea Ice Interactions: Local Processes and Global Implications

Convener(s): Petteri Uotila (Finland)

Co-Convener(s): John Cassano (USA), Takenobu Toyota (Japan, IACS), Amélie Kirchgaessner, William Perrie (Canada, IAPSO), Thomas Spengler (Norway)

Description
Changes in the Arctic and Antarctic climate system are strongly related to atmosphere-ocean-ice (AOI) interactions and feedbacks between snow, ice, the ocean, and atmosphere, such as snow processes, polynya formation, sea-ice production and deep-water formation. AIO interactions can be triggered by synoptic and mesoscale weather phenomena such as cold air outbreaks, katabatic winds, and polar lows. In the Arctic, for example, sea ice loss is associated with rapid regional warming which is often tightly linked to mid-latitude weather and climate. Furthermore, in the Antarctic, sea ice change may affect ice shelf behaviour and hence could affect sea level change. However, the representation of these physical, chemical, and biogeochemical processes and interactions at different spatial and temporal scales remains a major challenge for current weather and climate models. This symposium brings together researchers working in the areas of atmospheric and ocean boundary layers, sea ice, and snow-cover processes as well as on global change related to the marine Arctic and Antarctic. Further focus is on snow cover modelling, as well as snow ablation and accumulation on sea ice. In addition, the session focuses on processes and parametrizations related to physical and biogeochemical exchanges and transports, including the influence of sub-mesoscale ocean dynamics, where observational challenges can be addressed. Contributions dealing with theoretical and observational studies, including remote sensing, as well as studies using numerical models are welcome.



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M17 Space Weather Influence on Polar Lower Atmosphere

Convener(s): Tracy Moffat-Griffin (UK)

Co-Convener(s): Mark Clilverd (UK), Dan Marsh (UK)

Description
Space weather impacts the whole atmosphere, this session focusses on its influence on the high latitude lower atmosphere. We welcome abstracts that deal with research about space weather impacts on the lower atmosphere and possible mechanisms. This includes space weather impacts in the middle atmosphere (solar UV or particle precipitation) affecting regional climate.



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M18 60 Years Of ICPM

Convener(s): Matthew Lazzara (USA)

Co-Convener(s): Tracy Moffat-Griffin (UK)

Description
This session is to mark 60 years of the international commission of polar meteorology. We welcome abstracts that deal with past, current and future science projects that ICPM has been involved in and will be involved in.



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M19 Lightning Observations for Research and Applications in Meteorology and Climate

Convener(s): Eric Defer (France)

Co-Convener(s): Colin Price (Israel), Xiushu Qie (China)

Description
Lightning is closely related to the dynamical and microphysical processes in thunderstorm, and it can also serve as a good indicator of thunderstorm intensity and climate change. Thermodynamic and microphysical changes caused by climate changes or aerosol loads in atmosphere can also impact lightning activities. The session aims at presenting on-going research activities on thunderstorms and operational applications using ground-based and/or space-borne lightning observations alone or with auxiliary meteorological measurements. Topics of interest cover lightning detection techniques and data processing, observational and modeling-based studies of thunderstorm, lightning-based thunderstorm nowcasting, new developments in lightning data assimilation, effect of lightning on atmospheric composition, and the use of lightning records as essential climate variable.



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M20 Lightning Physics and Effects

Convener(s): Maribeth Stolzenburg (USA)

Co-Convener(s): Amitabh Nag (USA), Weitao Lyu (China)

Description
Intracloud, cloud-to-ground, and ground-to-cloud lightning is comprised of a variety of processes including initial or preliminary breakdown, leader steps, space stems and space leaders, needle-like discharges, recoil leaders, return strokes, and M-components. These and other processes produce light and electromagnetic emissions that can be measured by ground- and space-based sensors operating at different frequency ranges that provide researchers with waveforms, VHF locations, optical images, and spectral information, as well as energetic radiation signatures associated with the lightning. Lightning processes also have important effects in the upper atmosphere, including transient luminous events (TLEs), Terrestrial Gamma-ray Flashes (TGFs), and other forms of energetic radiation, all of which are undergoing intensive study from new platforms. All these lightning effects can pose a threat to lives and infrastructure. Modeling, often constrained by observations, is performed to describe different aspects of lightning processes and their effects. We invite scientific contributions that use observations and modeling to improve our understanding of lightning physics and all forms of lightning effects. Results from field and laboratory experiments, theoretical work, and numerical modeling, as well as inferences from lightning locating system data are welcome.



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M21 Thunderstorms and the Global Electrical Circuit

Convener(s): Yoav Yair (Israel)

Co-Convener(s): Giles Harrison (UK)

Description
At any given moment there are several thousands of active thunderstorms around the planet, with an average stroke rate of ~ 50 per second. Lightning is a marker of deep convection with significant impacts on atmospheric chemistry and it is often accompanied by severe weather phenomena such as hail, flash floods, tornadoes and downbursts. Lightning discharges and thunderstorm conduction currents maintain the ambient global electrical circuit (GEC), measurable as a downward pointing field in fair-weather regions, also manifested in a semi-constant electrical current flowing towards the Earth's surface. This session seeks contributions on the meteorology and microphysics of thunderstorms and its response to climate change. Observational techniques, case studies and numerical models of thunderstorms are of special interest. Also, we seek contributions on thunderstorm properties and the land-ocean contrast in lightning distributions, and how the electrical parameters of the GEC are affected by them. The role of electrified shower clouds, aerosols and pollution on the fair-weather electric field are also of interest, as well as short- and long-term trends in the GEC.



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M22 Cloud and Precipitation Studies

Convener(s): Greg McFarquhar (USA)

Co-Convener(s): Tom Lachlan-Cope (UK), Simon Alexander (Australia), Xin Yang (UK)

Description
Papers are solicited on theoretical, laboratory, observational and numerical modeling studies of cloud and precipitation microphysics and dynamics. The following topics (list non exhaustive) will be covered: Basic cloud and precipitation physics (including secondary ice formation processes); Dynamics and microphysics in different types of clouds (fog, boundary layer, convective, severe storms, stratus, cirrus, mid-latitude clouds, polar clouds, tropical clouds, monsoon clouds); cloud electrification; laboratory studies of processes occurring within clouds; measurement techniques and instrumentation development; parameterization of cloud and rain microphysical processes for representation in models; planned and inadvertent weather and climate modification. Separate sessions on high latitude clouds and tropical clouds are planned.



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M23 Cloud-Radiative Interactions

Convener(s): Greg McFarquhar (USA)

Co-Convener(s): Sebastian Schmidt (USA), Yi Huang (Australia), Mahen Konwar (India), David Noone (USA), Odran Sourdeval (France), Trude Storelvmo (Norway), Andreas Macke (Germany)

Description
The release of the 2021 IPCC report highlighted that the representation and understanding of cloud feedbacks and cloud-aerosol interactions remain significant uncertainties in refining prediction of future climate scenarios. Improving the understanding of cloud-radiation interactions is important for improving such representations and for development and evaluation of remote sensing retrieval schemes, the output of which are used for fundamental studies in both weather and climate. In this session, papers are solicited on theoretical, observational and modeling studies of interactions between clouds and radiation, including on the following non-exhaustive list of topics: aerosol-cloud-radiative interactions, cloud feedbacks, cloud radiative forcing, remote sensing retrieval schemes, cloud-radiative impacts on evolution of weather systems, cloud-radiative interactions for geoengineering and weather modification studies, limitations of the IPCC report, and energy transfer.



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M24 Dynamics and Microphysics of Moist Convection

Convener(s): Hugh Morrison (USA)

Co-Convener(s): Thara Prabhakaran (India), Daniel Kirshbaum (Canada), Christian Keil (Germany)

Description
Process-level understanding of moist convection is relevant to many aspects of weather forecasting and climate simulation. Moist convection in the atmosphere is inherently a multi-scale phenomenon, from processes on the scale of cloud and precipitation particles, to cloud turbulence and entrainment, to cloud-scale updrafts and downdrafts, to mesoscale organization and the interaction of cloud fields with the large-scale environment. A key aspect is how these processes interact over this huge range of scales. This symposium is focused particularly on the dynamical and microphysical processes determining the properties of cumulus clouds, how these clouds interact with the environment, and the representation of these clouds in weather and climate models. Contributions are welcome on a range of relevant topics including aerosol-microphysics-dynamics interactions, precipitation development in cumulus clouds, entrainment and detrainment, cloud turbulence, updraft and downdraft dynamics, the shallow-to-deep convective transition, convective-cold pool interactions, and convective organization and upscale growth. These may include perspectives from observations, theory, and/or modeling. The latter could involve parameterization development for weather and climate models (including artificial intelligence/machine learning approaches) and uncertainties of microphysical processes in short-range NWP models linked to convective-scale predictability.



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M25 Cloud Nucleation Studies

Convener(s): Zamin A. Kanji (Switzerland)

Co-Convener(s): Luis A. Ladino (Mexico), Heike Wex (Germany), Annica Ekman (Sweden)

Description
We invite submissions on the physical and chemical properties of aerosol impacting cloud hydrometeor nucleation, based on laboratory experiments, numerical modeling, remote sensing and field observations. In particular, we are interested in studies focusing on laboratory and field observations of cloud condensation nuclei (CCN) activation into droplets and ice nucleating particle (INP) activation into ice crystals for both mixed-phase cloud and cirrus cloud regimes. We encourage submissions that investigate the chemical and physical properties of atmospheric aerosol associated with the cloud forming processes of CCN and INP activation. This includes investigations of how processes of (photo)chemical transformations and reactions of aerosol as well as any morphological and physical changes in aerosol properties impact cloud hydrometeor formation. In addition, studies that combine observational and remote sensing techniques to infer processes related to cloud formation are highly welcomed. Finally, we encourage submissions of numerical modeling work from the moelecular to global scale that researches the impacts of aerosol properties on cloud formation, cloud microphysical and radiative properties. New methods and instruments used to understand aerosol impact on cloud nucleation are also welcomed.

Solicited speakers: Annele Virtanen (University of Eastern Finland, Finland), Paul DeMott (Colorado State University, USA), Christina McCluskey (National Centre for Atmospheric Research, USA)

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M26 Weather Modification and Small Scale Geoengineering: Theory, Practice and Technology

Convener(s): Ali M. Abshaev (Russia)

Co-Convener(s): Thara Prabhakaran (India), Roelof Burger (South Africa), Narihiro Orikasa (Japan)

Description
The threats of climate variability and change have reignited the debate on intentional weather modification and small-scale geoengineering. Alternative strategies to mitigate the impacts of severe weather on society are being explored. In the past few decades, the number of severe and adverse weather events has increased several times in many regions. World losses from natural disasters are currently estimated in the hundreds of billions dollars. According to World Meteorological Organization, more than 50 countries are conducting research and operational projects on hail suppression, precipitation enhancement, improvement of weather conditions, fog and smog dispersion. Several studies have announced promising figures regarding the potential for temperature amelioration locally. This special session aims to uncover new findings in weather modification science, insights from advanced weather models and experiments, explore emerging technological insights, debate the ethical implications of these technologies, and provide direction for future development of the field. Original scientific contributions that describe experiments and modelling studies, as well as reviewing the potential impacts and ethical implications will be considered. Possible topics include but are not limited to: hail suppression, rain enhancement, rain redistribution, fogs dispersion, frosts mitigation and suppression of lightning activity, Temperature Amelioration, Small Scale Geoengineering etc.



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M27 Atmospheric Chemistry in the Anthropocene: From the Urban to Global Scales

Convener(s): Lawrence Mark (Germany)

Co-Convener(s): Melita Keywood (Australia)

Description
In a world in which industrialization is proceeding at a significant pace, the world's population has now reached over 7.9 Billion. The associated increase in emissions to the atmosphere since the start of the Industrial Revolution in this era termed the Anthropocene by Paul Crutzen, has caused significant changes to the atmosphere. These changes impact the climate and air quality, which directly and indirectly cause significant health and quality of life issues to many populations, particularly those in vulnerable communities. In this session we invite contributions about laboratory, observation, modelling and mitigation of air quality and climate change on all time scales (process to long term programs to projections) and space scales (local to global). We particularly invite contributions on the lessons learned from the pandemic lockdowns and how this should influence action worldwide to improve air quality. Contributions on the impact of biomass burning and emissions from other extreme events the world has witnessed and experienced over the past decade are also welcome.



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M28 Advances in Dynamic Meteorology

Convener(s): Thomas Spengler (Norway)

Co-Convener(s): Gwendal Riviere (France), Seok-Woon Son (South Korea)

Description
The symposium focuses on advances in atmospheric dynamics based on theoretical, observational, diagnostic, and modelling studies. It deals with atmospheric phenomena of very different spatial scales including mesoscale, synoptic- and planetary-scales. Contributions are expected on storm track and jet-stream dynamics, eddy-mean flow interactions, frontal systems, cyclone and anticyclone evolution, blocking, stationary waves, stratosphere-troposphere coupling, dynamical connections between low, middle, and high-latitudes, and modes of atmospheric variability.

Solicited speakers: Shira Raveh-Rubin (Weizmann Institute of Science, Israel), Julian Quinting (KIT, Germany)

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M29 Dynamics of Mountain Weather and Climate: Observations, Modeling and Prediction at All Scales

Convener(s): Vanda Grubišić (USA)

Co-Convener(s): Mathias Rotach (Austria), Leila Carvalho (USA), Daniel Kirshbaum (Canada), James Doyle (Modeling and Pbi)

Description
The symposium focuses on dynamical processes that govern short-and long-term (climatic) state of the atmosphere influenced by orography, covering both wet and dry dynamics and a wide range of spatial and temporal scales. A special emphasis is on exchange processes of mass, momentum, energy between mountainous terrain and the free troposphere at all relevant scales. Contributions based on theoretical, observational, modeling, or combined approaches are invited on a range of topics including, but not limited to, orographic precipitation, mountain wind storms, convective initiation in complex terrain, gravity waves and gap flows, thermally-driven local circulations, mountain venting and meso-scale exchange processes, complex-terrain boundary-layer processes, air quality in complex terrain, hazards and extreme events and predictability of terrain-induced flows. Contributions addressing physical process studies, high-resolution numerical modeling and physical parameterizations as well as measurement techniques and observations from complex terrain field campaigns are all welcome.



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M30 Tropical Meteorology

Convener(s): Michael Reeder (Australia)

Co-Convener(s): Nedjeljka Žagar (Germany)

Description
The symposium will discuss recent advances in our understanding of the tropical circulation and thermodynamics. Relevant topics include, but are not limited to: the interactions with convection and clouds, wave motions, equatorial wave filtering, reduced models, and tropical cyclones. Contributions quantifying the interactions and feedback between different scales and their relative roles in driving tropical variability (e.g. Madden-Julian oscillation) in observations, (re)analyses, and weather and climate models are encouraged. Insights from recent observational campaigns (e.g. EUREC4A, Strateole-2) and new satellite measurements (e.g. ESA's Aeolus wind satellite) are particularly welcome, as are contributions on the impact of new observations on prediction skill of numerical weather prediction models. We also encourage contributions on the frontier challenges in tropical data assimilation, ensemble forecasting, predictability and related applications of machine learning.

Solicited speakers: Claire Vincent (University of Melbourne, Australia), Sam Stechmann (University of Wisconsin-Madison, USA)

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M31 Ocean-Atmosphere Mechanisms of Climate Variability, Change and Predictability

Convener(s): Tim Woollings (UK)

Co-Convener(s): Hisashi Nakamura (Japan), Iracema Cavalcanti (Brazil), Toshio Yamagata (Japan), Jingjia Luo (China)

Description
Interaction between the ocean and atmosphere plays an important role in many aspects of climate variability, predominantly from (sub)seasonal timescales upwards. The associated teleconnections cover the globe and can also interact with other systems such as the land and cryosphere. The long timescales inherent in such coupled variability proves an invaluable source of skill for near-term climate predictions in particular. Coupled variability on decadal and longer timescales is of increasing importance in the attribution and interpretation of emerging anthropogenic effects, and the longer term forced climate change signal is also significantly affected by ocean-atmosphere coupling. This symposium welcomes contributions of theoretical, modelling and observational work related to ocean-atmosphere variability and change. Specific topics covered by the symposium include but are not limited to: Tropical coupled variability and teleconnections; mechanisms of mid-latitude air-sea interaction; the role of ocean frontal zones and eddies in the coupled system; representation of air-sea interaction and teleconnections in climate models; role of ocean variability in decadal climate variability and near-term climate predictability; and ocean-atmosphere coupling under climate change.

Solicited speakers: Katinka Bellomo (Politecnico di Torino, Italy), Panos Athanasiadis (CMCC, Italy), June-Yi Lee (Pusan National University, Korea)

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M32 Sub-Seasonal to Decadal Prediction (S2S-S2D).

Convener(s): Frederic Vitart (UK)

Co-Convener(s): Seok-Woo Son (South Korea), Hannah Christensen (UK), June-Yi Lee (South Korea), Swadhin Behera (Japan)

Description
There is a growing interest in the research and application communities in developing sub-seasonal to seasonal (S2S: 2 weeks to a season) and seasonal to decadal (S2D: seasons to a decade) forecasts. This session invites contributions that span all aspects of meteorological and oceanographic prediction in the 2 weeks to a decade time range. The session will include both meteorological and impact studies. Contributions are welcome for studies of phenomena such as the Madden Julian Oscillation (MJO), ENSO, IOD, AMO, tropical/extratropical waves, ocean-atmosphere coupling, stratospheric variability, and stratosphere - troposphere coupling, in addition to studies of predictability/skill of oceanic,atmospheric or surface variables and case studies of high impact weather events. Contribution regarding impacts studies at the S2S and S2D time-range are welcome, including, but not limited to, the areas of hydrology, health, fire, agriculture, and energy. These can include modeling studies of the impacts right through to presentations of how S2S and S2D-derived information can be integrated into decision support systems at the local, regional and country level. Studies of prediction for marine and terrestrial ecosystems are also highly welcome.



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M33 Diagnosing and Reducing Errors and Biases in Weather and Climate Models

Convener(s): Nedjeljka Žagar (Germany)

Co-Convener(s): Jim Doyle (USA), Hannah Christensen (UK)

Description
Information about future weather and climate relies on complex numerical models of the Earth-system. Understanding, diagnosing, and reducing the errors in these models, and particularly those due to parameterizations, is a necessary step towards improved weather and climate prediction. We welcome contributions on topics such as: developments in parameterization; understanding the cause and nature of model error, particularly using seamless approaches across spatio-temporal scales; dependency of error on resolution, including scale-aware schemes and parameterization across the grey-zone; error growth and propagation in models; physics-dynamics coupling improvements; tools for diagnosing, understanding and quantifying model error, including observational constraints; impact of biases on simulated variability in remote regions; as well as applications of machine learning to any of the above.

Solicited speakers: Inna Polichtchouk (ECMWF, UK), Daisuke Takasuka (University of Tokyo, Japan)

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M34 Data Assimilation and Machine Learning in Earth Systems Modeling

Convener(s): Istvan Szunyogh (USA)

Co-Convener(s): Craig Bishop (Australia)

Description
The goal of both data assimilation (DA) and machine learning (ML) is to extract information from data. DA has been used for decades in Earth systems modeling primarily to obtain observation based estimates of the state of the systems. The resulting state estimates have served as initial conditions of numerical models and as the best estimate of the state of the systems in research studies. While the application of ML to Earth systems modeling has a much shorter history, it is arguably the most rapidly growing field of the discipline. ML models have been proposed to emulate computationally expensive physics-based components of numerical models, to estimate parameters of physics based parameterization schemes of the numerical models, to form hybrid models in which the numerical and ML component play a more equal role, and to replace numerical models entirely. ML has also been proposed for the estimation of parameters of the statistical models behind the DA schemes. In return, ML models are often trained on reanalyses data, which are state estimates produced by state-of-the-art DA systems. Not surprisingly, there are also ongoing efforts to integrate DA and ML more closely in Earth system modeling. We invite papers on all applications of DA, ML, or the combination of the two to Earth system modeling. Since many technical aspects of DA and ML are similar (e.g., minimizing cost functions, computing least-square estimates, linearizing nonlinear operators), we expect stimulating exchanges between participants from the two fields.



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M35 Exploration of the Diversity of Planetary Atmospheres: From the Solar System to Exo-Planets

Convener(s): Ann Vandaele (Belgium)

Co-Convener(s): Yeon Joo Lee (Korea), Nigel Mason (United Kingdom)

Description
In recent decades planetary atmospheric sciences revealed incredible level of diversity of atmospheres on each planetary body in our galaxy. Huge international efforts are made to better understand such diverse atmospheres. Such effort embraces a wide variety of research areas: developing remote sensing techniques, analysis of remote sensing data, understanding ocean/surface-atmosphere-space interactions, numerical calculations of radiative and dynamical atmospheric processes, understanding the evolution of these atmospheres, comparative planetology studies, and laboratory measurements in support to different planetary conditions. In this session papers will be solicited covering these diverse topics, providing the community a comprehensive approach to characterize diverse atmospheres.



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