(1) Elucidating the impact of rain on shallow convective organization using long-term observations of downdrafts (2) tbd (3) tbd (4) tbd

Longwave atmospheric cloud-radiative effect (LW ACRE) is important in supporting a variety of spatially organized moist systems in tropical weather and climate, from tropical cyclones, the Madden-Julian oscillation (MJO), to Walker circulation. Our works aim to understand the fundamental properties and the processes that generate the feedback between LW ACRE and tropical precipitating convection. I will discuss two major findings. (1) We explain why LW ACRE only supports larger-scale circulations, as in the MJO but not in mesoscale convective systems (MCSs), by studying a field campaign MCS case. (2) Why does such scale dependency exist? We propose a minimal conceptual recipe to quantitatively describe the scale dependency of LW-convection feedback by simply assuming that anvil clouds, which primarily generate LW ACRE, act as long-term memory of precipitation. The scale dependency of LW-convection feedback is, thus, a natural emerging property of longer memory of anvil clouds than precipitation. Finally, I will discuss how this conceptual model may provide information of how anvil LW ACRE is generated in tropical convective systems.

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The biosphere is a source and sink of gases and particles to the atmosphere. Thus, the biosphere sets the natural or
“preindustrial” chemical composition of the atmosphere. Human activity and climate change can perturb the
emissions to, deposition from, and chemistry within, the troposphere. At the same time, air pollution can impact
global ecosystem health, with implications for climate and food security. In this seminar, I will illustrate these ideas
with some recent studies from my group, highlighting in particular: (1) fire as a source of ozone and aerosols, (2) preindustrial
to future evolution of biogenic organic aerosol, and (3) the impact of ozone and air pollution on natural and
managed ecosystem health.

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(1) Observing mesoscale variability with KITsondes during NAWDIC (2) Improving Subseasonal Weather Forecast using Tropical Weighting: A Fine-Tuned 2D Transformer (3) Callie Maier (4) tbd

Hail and severe convective storms rank among the most damaging weather hazards in Central Europe. Relevant processes span a range of scales: from hailstone growth at the microphysical level over storm dynamics and organization on the mesoscale to larger-scale synoptic environments and long-term climate change. The analysis of societal risk adds complexity, since impacts depend on exposure, vulnerability, and how extremes combine. This talk brings together several lines of research, linking processes to impacts across scales. Firstly, we investigate if we can learn about relevant processes from machine learning models that predict observed hail stone sizes. Secondly, on a regional scale, we explore whether emerging convective hotspots around the European Alps can be connected to large-scale patterns. Finally, we focus on impact relevance, presenting resampling and storyline approaches that allow for process-sensitive risk modeling to address both short-term and long-term impact assessments.

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