A simple set of indices describing the Tropical Rain Belt over central and southern Africa

Abstract

Abstract Understanding the variability of the Tropical Rain Belt (TRB) in Africa is a challenging task due to complex interactions among global, regional and local drivers of rainfall. A simple method that provides a set of three indices describing large‐scale spatial–temporal characteristics of the TRB over central and southern Africa is introduced. The method is based on approximation of a meridional cross‐section of monthly mean precipitation by the Gaussian function. The three parameters of the Gaussian function correspond to the three TRB indices, namely: intensity, location and width. It is shown how the TRB indices can be used for describing the climatology of the TRB, for estimating observational uncertainties, and for evaluating the ERA‐Interim and ERA5 reanalyses against observations. Simplicity and flexibility of the method allow using the TRB indices for a wide range of applications, including evaluation of climate models and assessment of projected climate change in tropical rainfall.

Keywords

• Africa
• climate
• index
• proxy
• rain belt
• variability