Atmosphere Ocean Science Colloquium
Gravity waves, radiative feedbacks, and climate change over mountains
Speaker: William Boos, Berkeley
Location: Warren Weaver Hall 1302
Date: Wednesday, March 4, 2026, 3:30 p.m.
Synopsis:
Over half the global human population depends on water resources obtained from mountains and high plateaus, and this fraction of the global population is projected to grow in coming decades. Yet the atmospheric processes that supply this water in the form of orographic precipitation are poorly understood, especially in the tropics where elevated terrain alters precipitation by modifying ensembles of convective clouds. How these processes will change in coming decades is also unknown.
This talk will present new findings on the mechanisms that govern the response of tropical orographic precipitation to variations in global and regional climate. We will show that mechanically forced tropical orographic precipitation is extremely sensitive to the magnitude of the cross-slope wind speed, and explain how these sensitivities arise from orographic gravity wave dynamics. We will also discuss the phenomenon of "elevation-dependent warming", in which elevated land surfaces warm faster than non-elevated ones when subject to a greenhouse gas forcing. We will show that particular radiative feedbacks enhance warming over elevated terrain, while others suppress it. These results bring us closer to a complete understanding of how the water resources derived from mountains will respond to future changes in winds and temperatures.