Collaborative Research: Quantifying the impacts of atmospheric and land surface heterogeneity and scale on soil moisture-precipitation feedbacks

Columbia University, New York NY

Investigators

Abstract

This project studies the potential feedback between soil moisture and precipitation. A positive feedback would mean that enhanced soil moisture leads to enhanced precipitation, as a wetter surface provides a source of evaporation for subsequent rainfall. In that case, precipitation would lead to wetter soil, which would in turn lead to further precipitation, while a lack of precipitation could lead to a lack of soil moisture and hence further reductions in precipitation leading to prolonged drought. This study assesses the influence of atmospheric and land surface heterogeneity and spatial scale on soil moisture-precipitation coupling, principally at daily timescales, through two interconnected approaches: 1) diagnostic analysis of available observations, reanalysis products, and global climate model (GCM) output; and 2) conceptual modeling of land-atmosphere interactions using process-based idealized models expresed as analytic equations as well as atmospheric column models coupled to simple soil models (eg "bucket" models). A primary objective of this activity is the development of robust, physically-based metrics for quantifying and comparing intraday soil moisture/precipitation coupling in models and observations. The issues addressed in this project have relevance to society as well as science, as drought duration and intensity have substantial consequences for agriculture. In addition, the project will support and train a postdoctoral researcher, thereby helping to support and train the next generation of scientists.