Aerosols capable of absorbing sunlight such as smoke and dust interact with their larger-scale environment through processes that are distinct from those linked to scattering-only aerosols. Prevailing wind patterns can transport the dust and smoke far from their sources, providing vast spatial coverages. The diabatic heating from shortwave absorption provides a warming to climate, affecting regional cloud and precipitation patterns. The aerosol impacts depend on the amount of sunlight absorbed, which in turn is sensitive to the single-scattering albedo, the aerosol loading, and the albedo underlying the aerosol layer. The small-scale radiative-cloud interactions will depend on the relative vertical cloud-aerosol location. Clouds can thicken, for example through an increase in the lower-tropospheric stability, or thin, for example through a decrease of relative humidity if temperatures increase in the boundary layer. The cloud response will also differ depending on how the attenuated solar radiation affects the surface and boundary layer turbulent fluxes (e.g., if the surface is ocean or land). Aerosol deposition is also important to the surface properties. Presentations are solicited on the scientific advancements in the characterization of the aerosol properties, and the processes through which the aerosol heating interacts with its environment at all scales, from cloud-scale to the large-scale circulation. These include fieldwork, lab experiments, and modeling investigations.

Soil dust from a variety of sources contributes a major fraction to the atmospheric aerosol and has strong impacts on the environment, the weather systems, and the global climate. The goal of this session is to bring together scientists from different disciplines working on the emission, atmospheric transport, transformation, physical, and chemical characterization, as well as cloud, weather, and climate impacts of soil dust from deserts, semi-arid regions, or agricultural areas. Of particular interest are questions about the speciation and atmospheric impact of different mineral, organic, and biological components in the soil dust of different origin. We invite and welcome laboratory, field, and modeling contributions from the general areas of (1) mineralogy, organic content, and other constituents of dust sampled from source regions or directly from the atmosphere; (2) emission fluxes, transport, and chemical transformation of dust in the atmosphere; and (3) cloud, weather, and climate impact, including optical properties and cloud microphysics like CCN activation and heterogeneous ice nucleation.

Aerosol–cloud interactions have significant influences on natural climate variability and are also one of the largest uncertainties in the estimate of anthropogenic climate forcing. This session seeks presentations of recent research work that advances the understanding of how various aerosol–cloud interactions impact the local and/or global radiative energy budget and consequent implications for climate change. We welcome discussion forums related to i) how microphysical interactions between aerosol and cloud modulate the cloud radiative properties and radiative effects (e.g., Twomey and lifetime effect), ii) how the relative position of aerosol and cloud (e.g., aerosol above, below, and inside clouds) influences the radiative energy distribution, and iii) novel measurement (remote sensing and in situ) and modeling techniques to quantify the impacts of aerosol–cloud interactions on radiation.

2018 Haurwitz Lecture

Core Science Keynote Presentations

Aerosol–Cloud–Climate Interactions Posters

The Robert T. Ryan Symposium will conclude with a cocktail reception welcoming symposium attendees, along with Bob's numerous colleagues and former interns from across the weather enterprise. With a short program hosted by symposium co-chair and AMS Fellow Veronica Johnson of WJLA in Washington, D.C., this casual event will honor Bob for his distinguished career, achievements, and contributions to the American Meteorological Society.

Understanding the interactions between aerosol particles and deep convective clouds is challenging for a number of reasons. Aerosol particles influence the microphysical properties, latent heat release, and ultimately the dynamics of these storms. Characteristics of the anvils, hydrometeors, surface precipitation, and cold pools can be significantly altered as a result. Deep convective clouds are in turn important for removing and redistributing aerosol particles in the atmosphere. For this session, we seek presentations on interactions between aerosols and all types of isolated and organized deep convection in the tropics and midlatitudes, including mesoscale convective systems and hurricanes. Papers focusing on aspects of aerosol–deep convection interactions such as precipitation, cloud microphysical and radiative properties, cold pools, and storm dynamics are welcomed. Papers on deep convective transport of aerosols and dust are also strongly encouraged.

Climate and environmental conditions in the polar regions are undergoing drastic changes. Recent in situ and space-borne measurements revealed frequent Arctic haze formation from local sources (e.g., shipping, wild fires, industrial activities, and residential combustion) or transported from mid-latitude regions, which calls for a quantitative assessment of impacts of anthropogenic aerosols on the Arctic atmosphere and cryosphere. Meanwhile, natural aerosols from marine biosphere, biomass smoke, and volcano are also closely linked to the polar cloud and climate changes. This session solicits papers addressing observations and modeling of sources and transport of aerosols in the high latitudes, aerosol effects on the mixed phase and ice clouds, aerosol snow-albedo effects, cloud–radiation–sea ice interactions, the role of aerosols in the sea ice and land ice melting, etc.

N/A

We encourage all attendees to take the opportunity to grab a snack and coffee and spend this extended afternoon break networking with colleagues and viewing the hundreds of posters on display in the poster hall. Poster displays are grouped by conference and change each day.

Aerosol–Cloud–Climate Interactions Posters

How and to what extent the mineral dust aerosols can affect regional weather systems, global circulation patterns, and climate variability remains an open question. Answering the above question requires comprehensive understanding of the direct, indirect, and semi-direct radiative effects of dust in order to accurately model the energy budget of the atmosphere and surface. The dust-induced changes to the energy budget are manifest in cloud processes and the thermal structure of the atmosphere, and consequently the circulation. The dust-modified circulation, in turn, alters the dust transport by the mean and eddy portions of the flow. Examples of dust-modified circulations include, but are not limited to, the African easterly jet–African easterly wave system, the African monsoon, tropical cyclones, mesoscale convective complexes, and springtime cyclones over Southern Europe, Mongolia, and China.

Co-Chairs: Terry Nathan, Shuhua Chen

We encourage all attendees to take the opportunity to grab a snack and coffee and spend this extended afternoon break networking with colleagues and viewing the hundreds of posters on display in the poster hall. Poster displays are grouped by conference and change each day.

Aerosol–Cloud–Climate Interactions Posters

Many shallow cloud systems are sensitive to changes in aerosol properties, which act as cloud condensation nuclei (CCN, or giant CCN), modulate cloud microphysical properties, and can influence precipitation formation and cloud scale dynamics. In addition, absorbing aerosols can modulate the thermodynamic environment experienced by clouds. Ultimately, these controls may alter low cloud radiative properties and climate. Aerosol particles, in turn, are impacted by shallow cloud processes. Together, these interactions result in a coupling of the aerosol–cloud system whose coupling strength is highly variable and is poorly understood in terms of basic process understanding. Correctly representing this coupling has proven challenging to represent in large scale models. In this session, we invite presentations on all topics related to aerosol–cloud coupling in shallow clouds, including those addressing basic physical understanding, the quantification of aerosol indirect effects, cloud effects on aerosols, and the coupling between aerosols and boundary layer turbulence, cloud dynamics, and precipitation.

Atmospheric aerosols originate from multiple natural and anthropogenic sources, and their emission strengths depend strongly on a combination of biological, geologic, human, and meteorological factors. Once emitted into the atmosphere, they often form complex mixtures that affect the earth system on multiple spatial and temporal scales. Natural aerosols can undergo volatilization and condensation, aggregation and disaggregation, photochemical reactions, and mixing with other compounds as they are transported downwind leading to heterogeneous structure both chemically and physically. Current studies show that these aerosol mixtures can have strong impacts on human health, ecosystems, global climate, and weather. It is important to understand these complex aerosol mixtures including their chemical make-up, biological implications, and physical properties, as well as their distribution, fate, and transport in the atmosphere. Recent advances in aerosol modeling have opened a wealth of questions pertaining to the relationship of aerosol chemical evolution, new particle formation, compositional influences on cloud microphysics, and radiative balance. Despite these advances, challenges remain with respect to model verification of aerosol distributions and aerosol properties—especially in under-sampled regions of the globe. This session solicits presentations of research studies on naturally occurring aerosols; e.g., mineral dust, wildfire smoke, sea salt, pollen, and biogenic particles, with a focus on multidisciplinary efforts that investigate their emissions strength, source properties, physical complexity and mixtures, chemical transformations, and transport. Many of these aerosols are directly emitted from other parts of the Earth system, but others can also form or be modified in the atmosphere due to interaction with gaseous emissions and photochemical reactions. This is especially the case with biogenic aerosols, where gas phase volatile organic compounds are emitted that may serve as precursors to secondary organic aerosol formation. Presentations that discuss the novel advances in measurement, modeling and analysis of naturally occurring aerosols including the characterization of the composition of aerosol mixtures, quantifying emission strength, understanding transport and photochemical evolution, and estimating their weather, climate, ecological, or health & safety implications are also invited. Through this session, we hope to catalyze discussions on the chemistry, physics, and biology of aerosols from emissions to impacts.