Coupling hotspots: distinguishing between positive and negative land-atmosphere interaction

TL;DR

This paper analyzes land-atmosphere interactions, revealing how soil moisture variances influence coupling hotspots and their role in extreme climate events, with implications for climate prediction and vulnerability assessment.

Contribution

It establishes analytical relationships linking soil moisture variances to coupling hotspots and identifies regions with different feedback signs affecting climate extremes.

Findings

Soil moisture variances control coupling hotspot locations.

Different feedback signs can reinforce or attenuate extreme climates.

New hotspots identified where precipitation is sensitive to soil moisture.

Abstract

Understanding the complex interactions between land surface and atmosphere is essential to improve weather and climate predictions. Various numerical experiments have suggested that regions of strong coupling strength (hotspots) are located in the transitional climate zones. However, atmospheric processes in these hotspots are found to have different responses to the perturbation of surface properties. Here we establish analytical relationships to identify key role of soil moisture variances in controlling the coupling hotspots. Using the most recent numerical experiments, we find different signs of feedback in two such hotspots, suggesting the coupling can either reinforce or attenuate persistent extreme climates. We further uncover new coupling hotspots in regions where precipitation is highly sensitive to soil moisture perturbation. Our results highlight the importance of both signs and magnitudes of land-atmosphere interactions over extensive regions, where the ecosystems and communities are particularly vulnerable to the extreme climate events.