Land Surface Temperature Trend and Its Drivers in East Africa

Abstract

Land surface temperature (LST) is affected by surface-atmosphere interaction. Yet, the degree to which surface and atmospheric factors impact the magnitude of LST trend is not well established. Here, we used surface energy balance, boosted regression tree model, and satellite observation and reanalysis data to unravel the effects of surface factors (albedo, sensible heat, latent heat, and ground heat) as well as incoming radiation (shortwave and longwave) on LST trends in East Africa (EA). Our result showed that 11% of EA was affected by significant (p < 0.05) daytime annual LST trends, which exhibited both cooling of −0.19 K year −1 (mainly in South Sudan and Sudan) and warming of 0.22 K year −1 (mainly in Somalia and Kenya). The nighttime LST trends affected a large part of EA (31%) and were dominated by significant warming trend (0.06 K year −1). Influenced by contrasting daytime and nighttime LST trends, the diurnal LST range reduced in 15% of EA. The modeling result showed that latent heat flux (32%), incoming longwave radiation (30%), and shortwave radiation (23%) were stronger in explaining daytime LST trend. The effects of surface factors were stronger in both cooling and warming trends, whereas atmospheric factors had stronger control only on surface cooling trends. These results indicate the differential control of surface and atmospheric factors on warming and cooling trends, highlighting the importance of considering both factors for accurate evaluation of the LST trends in the future.

Representation of land–atmosphere coupling processes over Africa in coupled model intercomparison project Phase 6

“…Over regions of strong coupling in the Sahel and Eastern Africa, land-atmosphere coupling has been linked with the increase in surface temperatures during anomalously low SM events at sub-seasonal to seasonal timescales (Talib et al 2022;Abera et al 2020). This is related to SM controlling the partitioning of latent and sensible heat flux in transitional zones (Gallego-Elvira et al 2019).…”

“…The impact of soil moisture anomalies has been demonstrated to influence local to regional climate beyond planetary boundary layer (PBL) variables. Over East Africa, Abera et al (2020) noted that land surface characteristics such as leaf area index and soil moisture control about 47% of the temporal variability of surface temperatures. Moreover, Dirmeyer et al (2009) reported that soil moisture memory persisted for up to about 40 days in Southern Africa.…”

Opportunities and Challenges of Spaceborne Sensors in Delineating Land Surface Temperature Trends: A Review

“…Studies have also been conducted finding relationships of temperature trends with wind firms [73]- [75], earthquake impact [76], CO2 emission [77], and vector borne diseases [78]. Driving factors or causes of warming or cooling trends were also studied [19,33,46,49,[79][80][81]. Most of these studies were conducted using MODIS LST data with a spatial resolution of 1 km, and a few with 5.6 km.…”

Satellite-Derived Land Surface Temperature Dynamics in the Context of Global Change—A Review

“…Figure 1 provides an overview of the application fields of LST. LST has been used to study global warming [3][4][5][6][7][8][9][10][11][12][13][14][15][16], interannual climate variabilities [5,[7][8][9][10]14,17], heat waves [18][19][20], droughts [21][22][23][24][25], soil moisture dynamics [22,23,[26][27][28][29], forest dynamics [28,[30][31][32][33][34][35][36][37][38][39], general vegetation-temperature interactions [15,20,[24]…”