Speaker: Prof. Hsin Hsu 徐辛 (International Degree Program in Climate Change and Sustainable Development, National Taiwan University)

Title: Soil Moisture Regimes as a Framework to Understand Hydroclimate Change and Extremes

Time: 02:20pm Tuesday 14/Apr/2026

Venue: Room S101, 1F, Lecture Hall (G112)

Abstract:

Recognizing soil moisture regimes provides a fundamental framework for understanding hydroclimate dynamics. The relationship between soil moisture and evapotranspiration is inherently nonlinear, with dry, transitional, and wet regimes defined by whether land-surface fluxes are limited primarily by water availability or by energy. These regimes play a central role in regulating how the land surface modulates climate variability and extremes. The rapidly expanding availability of daily records of soil moisture, surface heat fluxes, and near-surface atmospheric states has enabled the development of data-driven approaches to track soil moisture regimes. Through the recognition of soil moisture regimes, substantial progress has been made in understanding land–climate interactions, hydroclimate change, and associated dry-hot extremes in past few years.

In this talk, I will discuss: (1) recent approaches for diagnosing soil moisture regimes and the associated metrics derived from these diagnostics; (2) how soil moisture regimes, and their control on evapotranspiration, shape historically significant compound hot–dry extreme events; (3) a new empirical framework that bypasses explicit soil moisture regime classification to interpret changes in historical evapotranspiration; and (4) my perspectives on future research directions related to soil moisture regimes and changing evapotranspiration.