Satellite-based rainfall data reveal a recent drying trend in central equatorial Africa

• Published in: Climatic change Vol. 126; no. 1-2; pp. 263 - 272
• Main Authors: Diem, Jeremy E, Ryan, Sadie J, Hartter, Joel, Palace, Michael W
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.09.2014; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Aerosols; Annual rainfall; Atmospheric Sciences; autumn; Biodiversity; Biodiversity hot spots; Biomass; Biomass burning; burning; Climate; Climate change; Climate Change/Climate Change Impacts; Climate science; Climatology; data collection; Datasets; dry season; Drying; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Endangered species; Estimating; Exact sciences and technology; External geophysics; Food security; Global warming; Growing season; human population; Human populations; Hydrologic data; Letter; Mesoscale convective complexes; meteorological data; Meteorology; Novellas; Rain; rain forests; Rainfall; Rainforests; satellites; Sea surface temperature; Seasons; Subsistence agriculture; subsistence farming; Summer; surface water temperature; Trends; Water in the atmosphere (humidity, clouds, evaporation, precipitation); Wildlife conservation; Somalia; Uganda; Democratic Republic of the Congo; Indian Ocean; Atlantic Ocean; Republic of the Congo; Central Africa; East Africa; Africa; AN, North Atlantic; ISW, Indian Ocean; ISW, Somalia; Indian Ocean Dipole; Carbonaceous Aerosol; Atlantic Multidecadal Oscillation; Boreal Summer; Rainfall Trend; time series analysis; Dry out; Climatology; rainfall; trend-surface analysis; atmospheric precipitation; 1990-2000; Space remote sensing; 2000-2010; Observation data; Satellite observation; 1980-1990
• DOI: 10.1007/s10584-014-1217-x
• ISSN: 0165-0009

West-central Uganda, a biodiversity hotspot on the eastern edge of central equatorial Africa (CEA), is a region coping with balancing food security needs of a rapidly growing human population dependent on subsistence agriculture with the conservation of critically endangered species. Documenting and understanding rainfall trends is thus of critical importance in west-central Uganda, but sparse information exists on rainfall trends in CEA during the past several decades. The recently created African Rainfall Climatology version 2 (ARC2) dataset has been shown to perform satisfactorily at identifying rainfall days and estimating seasonal rainfall totals in west-central Uganda. Therefore, we use ARC2 data to assess rainfall trends in west-central Uganda and other parts of equatorial Africa from 1983–2012. The core variables examined were three-month rainfall variables for west-central Uganda, and annual rainfall variables and seasonal rainfall totals for a transect that extended from northwestern Democratic Republic of the Congo to southern Somalia. Significant decreases in rainfall in west-central Uganda occurred for multiple three-month periods centered on boreal summer, and rainfall associated with the two growing seasons decreased by 20 % from 1983–2012. The drying trend in west-central Uganda extended westward into the Congo rainforest. Rainfall in CEA was significantly correlated with the Atlantic Multidecadal Oscillation (AMO) at the annual scale and during boreal summer and autumn. Two other possible causes of the decreasing rainfall in CEA besides North Atlantic Ocean sea-surface temperatures (e.g., AMO), are the warming of the Indian Ocean and increasing concentrations of carbonaceous aerosols over tropical Africa from biomass burning.