Publications

Flegrová, M; Brindley, H (2025). Two Decades of Fire-Induced Albedo Change and Associated Short-Wave Radiative Effect Over Sub-Saharan Africa. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 130(2), e2024JD041491.

Abstract
We present an analysis of 20 years of fire and albedo data in Africa. We show that, in the mean, the sub-Saharan Africa post-fire surface albedo anomaly can be parameterized using an exponential recovery function, recovering from a decrease of 0.019 +/- 0.001 $0.019\pm 0.001$ immediately after a fire with a time constant of 34.0 +/- 0.4 $34.0\pm 0.4$ days. Although the magnitude of albedo changes shows large spatial and temporal variations and a strong land cover type (LCT) dependency, exponential recovery is observed in the majority of LCTs. We show that fires cause long-term surface brightening, with an Africa-wide albedo increase of (9.5 +/- 0.2)x10-4 $(9.5\pm 0.2)\times 1{0}<^>{-4}$ 10 months after a fire, but we find this is driven almost exclusively by slow vegetation recovery in the Kalahari region, confirming previous findings. Using downward surface shortwave flux (DSSF) estimates, we calculate the fire-induced surface radiative forcing (RF), peaking at 5 +/- 2 $5\pm 2$ Wm-2 in the burn areas, albeit with a significantly smaller effect when averaged temporally and spatially. We find that the long-term RF in months 5-10 after a burn averaged over the continent is negative because of the brightening observed. Despite a well-documented reduction in burning in Africa in the recent decades, our temporal analysis does not indicate a decrease in the overall fire-induced RF likely due to large interannual variability in albedo anomaly and DSSF data. However, we observe a decline in the short-term RF in southern hemisphere Africa, driven by both a reduction in fires and changes in LCT distributions.

DOI:
10.1029/2024JD041491

ISSN:
2169-8996