A Simple Theory for Increasing Unevenness in Tropical Rainfall with Warming
Abstract
Tropical rainfall on average increases with global warming. However, dry regions experience rainfall reductions, while wet regions receive even more rain. Here we present a simple theory to quantitatively capture this behavior. We first lay the foundation by showing that two idealized theories, namely convective quasi-equilibrium (QE) and weak temperature gradient (WTG), can form a zeroth-order picture for the relationship between rainfall and subcloud moist static energy (MSE) in the tropics. Then we show that subcloud MSE gradients are amplified in a warmer world, and thus the present day wet regions will become more competitive for convection. The central result of this work is a theoretical scaling that explains this amplification of subcloud MSE gradients based on the Clausius Clapeyron relationship, the assumption of uniform warming, and constant relative humidity.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMU002...08Z
- Keywords:
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- 0810 Post-secondary education;
- EDUCATION;
- 0815 Informal education;
- EDUCATION