When
Where
Available in person and via zoom (see email for link)
Abstract
Energetic, thermodynamic, and dynamic constraints provide the first principles for global mean hydroclimate changes, but their land-based implications are complicated by soil moisture limitations and heterogeneous surface properties. In this talk, I will first present a process-oriented phase space that brings divergent model predictions into coherent patterns, allowing local, daily mechanistic relationships among hydroclimatic variables to be interpreted within the context of global energetic constraints and wet-get-wetter/dry-get-drier paradigm. These patterns also highlight the sensitivity of temperature extremes to soil moisture limitation. I will further illustrate the role of soil moisture and atmospheric circulation using a large ensemble of simulations of the 2021 Pacific Northwest heatwave, examining how land–atmosphere interactions evolve when initialized with different land states under circulation constrained to observations. Next, I will discuss humid heatwaves in the tropics, emphasizing how lower-free-tropospheric dry air can elevate the theoretical upper limit of moist heat derived from convection and dynamics. This mechanism also explains why extreme moist heatwaves occur not only in warm, humid regions with active convection, but also in convectively suppressed coastal zones adjacent to hot, arid land. Finally, I will briefly touch on the extreme-range precipitation probabilities of various weather systems.
Bio
Suqin Duan is currently an assistant project scientist at UCLA, studying heatwaves and precipitation extremes. Before joining UCLA, she was a postdoctoral research associate at Princeton, working on hydroclimate change and land atmosphere interaction. Her PhD work focuses on using stable water isotopes to constrain tropical convection.