Subtropical weather and climate processes in the past, present, and future

Co-organized by CL3.1

Convener: Andries Jan De Vries | Co-conveners: Marcia Zilli, Irina Rudeva, George Zittis, Moshe ArmonECSECS

Atmospheric processes in both the tropics and midlatitudes are central to shaping weather, climate, and extreme events in the subtropics. The complexity of these processes and their interactions give rise to a unique hydroclimate characterized by strong spatial gradients, distinct seasonal cycles, and high sensitivity to variability and change. Subtropical regions are global hotspot regions of climate change, and yet, remain plagued by large uncertainty in climate model simulations. They are also home to a large share of the world’s population, including communities in the Global South that are disproportionately at risk from extreme events and climate change. Despite their societal and scientific importance, subtropical weather and climate processes remain comparatively understudied.

This session invites contributions that advance process understanding and prediction of weather and climate with a particular focus on the subtropics. We welcome studies based on observations, theory, numerical models, and machine learning. Topics of interest include, but are not limited to:
• Atmospheric processes shaping clouds, circulation patterns, dust and air pollution transport, and surface weather such as tropical–extratropical interactions, subtropical jet fluctuations, Rossby wave dynamics, transient eddies, monsoon circulations, and convergence zones.
• Weather, climate, and compound extremes – droughts, heatwaves, wildfires, heavy precipitation, flooding, dust storms, and windstorms – spanning their drivers, future changes, and impacts on society and ecosystems.
• The water cycle – rainfall, evapotranspiration, and moisture transport – modulated by weather systems such as cyclones, cutoff lows, cold air outbreaks, mesoscale convective systems, easterly waves, and atmospheric rivers.
• Coupled interactions between Earth system components, including land-atmosphere and ocean-atmosphere feedbacks, and the role of sea surface temperature patterns in shaping subtropical climate.
• Climate variability and remote linkages with ENSO, the Madden-Julian Oscillation (MJO), and the Hadley circulation.
• Observations and climate model simulations addressing past and future changes in regional circulation patterns and surface weather, and novel approaches for identifying model biases and for reducing uncertainties in projections.