Albedo changes after fire as an explanation of fire‐induced rainfall suppression

Abstract

Observational evidence of rainfall suppression by fire has recently been documented in African drylands, but the underlying mechanism remains poorly understood. Here we investigate the extent to which fire‐induced changes in latent heat flux and albedo may inhibit boundary layer predisposition to convective rainfall. We use Modern‐Era Retrospective analysis for Research and Applications, Version 2 reanalysis data from the Kalahari region of Southern Africa to drive a low‐dimensional boundary layer growth model. We find that both increased albedo and, to a lesser extent, increased latent heat flux could result in less convective rainfall. The sensitivity to land surface feedbacks is higher earlier in the dry season and at drier sites. Finally, using Moderate Resolution Imaging Spectroradiometer fire and albedo data, we present novel evidence that increases in albedo after fire, or brightening, are common in regions receiving less than 850 mm of precipitation annually. This supports the idea that fire‐induced surface brightening is responsible for observed rainfall deficits after fire.

The Global Land Carbon Cycle Simulated With ISBA‐CTRIP: Improvements Over the Last Decade

“…They also affect other fluxes and pools, like the reduction of aboveground litter due to fire. But they are also needed when running in coupled mode within the Earth System Model CNRM‐ESM as DOC is one of the main inputs of C to the global ocean (Resplandy et al, 2018) and fires and LCC also affect the physical climate (see for instance Saha, D'Odoricco, & Scanlon, 2017 for fire and De Noblet‐Ducoudré et al, 2012 or Lawrence & Chase, 2010 for LCC).…”

The Effects of Tropical Vegetation on Rainfall

“…The majority of studies across the Amazon have focused on deforestation patches in the heavily deforested southern Amazon, where the analysis is complicated by biomass-burning aerosol associated with deforestation and the coincidence of meteorological and land-cover gradients (80). Over the Sahel, negative correlations between dry season fires and following wet season rainfall suggest reduced rain over devegetated regions (81), potentially driven by increased albedo (82).…”

Inducing Factors and Impacts of the October 2017 California Wildfires

“…Such a significant CO 2 source needs to be considered in the current studies of environment and model simulation. Previous study (Saha et al, ) also found that the fire can increase albedo and latent heat, which leads to less convective precipitation. As suggested in Saha et al (), the brightening after fire as a result of drier soils and losing senescent vegetation is responsible for rainfall suppression.…”

“…Previous study (Saha et al, ) also found that the fire can increase albedo and latent heat, which leads to less convective precipitation. As suggested in Saha et al (), the brightening after fire as a result of drier soils and losing senescent vegetation is responsible for rainfall suppression. It will further lead to more severe droughts and wildfires in California in the future, which will release more CO 2 to the atmosphere.…”