Two decades of fire-induced albedo change and associated short-wave radiative effect over sub-Saharan Africa
Author(s)
Flegrova, Michaela
Brindley, Helen
Type
Journal Article
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 immediately after a fire with a time constant of
34.0 ± 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) × 10− 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 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.
function, recovering from a decrease of 0.019 ± 0.001 immediately after a fire with a time constant of
34.0 ± 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) × 10− 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 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.
Date Issued
2025-01-28
Date Acceptance
2024-12-25
Citation
Journal of Geophysical Research (JGR): Atmospheres, 2025, 130 (2)
ISSN
2169-897X
Publisher
American Geophysical Union
Journal / Book Title
Journal of Geophysical Research (JGR): Atmospheres
Volume
130
Issue
2
Copyright Statement
© 2025. The Author(s). This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Subjects
Africa
albedo
ALGORITHM
ATMOSPHERIC COMPOSITION
CLIMATE
COVER
DYNAMICS
ECOSYSTEM
fire
Meteorology & Atmospheric Sciences
MODIS
Physical Sciences
Science & Technology
shortwave radiative forcing
TROPICS
Publication Status
Published
Article Number
e2024JD041491
Date Publish Online
2025-01-21