TITLE:
Comparative Study of Atmospheric Temperature Climate Trends over Central Africa Republic from Satellite and Reanalysis Data
AUTHORS:
Abdoul Nassir Silla, Zhengkun Qin, Andrew Friday Hakabinga, Bakar Mohammed Yussuf, Tanimu Abubakar Sadiq
KEYWORDS:
Air Temperature, Climate Trend, Nonlinear Trend, AMSU-A, Reanalysis
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.4,
April
28,
2026
ABSTRACT: Accurate and homogeneous long-term temperature records are essential for reliably estimating the rate of global warming and informing appropriate adaptation strategies. However, the Central African Republic (CAR) is characterized by an extremely sparse and irregular network of meteorological observations, which severely hampers the nation’s ability to assess and respond to climate-related hazards. To better estimate atmospheric warming rates over CAR and evaluate the applicability of reanalysis products in this region, this study conducts a systematic comparative analysis of atmospheric temperature trends using satellite-based observations from the Advanced Microwave Sounding Unit-A (AMSU-A) during 2000-2020, in conjunction with three state-of-the-art reanalysis products: ERA5, JRA-55, and MERRA-2. Linear and nonlinear trend analyses are performed on regionally averaged temperature anomalies at three pressure levels (500, 250, and 100 hPa). All datasets reveal statistically significant warming in the troposphere and lower stratosphere. The satellite-derived warming rates over CAR are 0.576, 0.243, and 0.324˚C/decade at the three levels, respectively, which are generally larger than those from the reanalysis products. The brightness temperature trends show better agreement with reanalysis data at 500 hPa and 100 hPa, whereas substantial discrepancies are evident at 250 hPa in the transition zone. The differences in nonlinear trends are even more pronounced: the satellite observations exhibit distinct nonlinear warming characteristics, whereas all reanalysis products demonstrate approximately linear trends. Inter-comparison among the reanalysis products indicates notable discrepancies in temperature trends, with differences exceeding a factor of two in the lower troposphere. Among the three reanalysis products, ERA5 shows the closest agreement with satellite observations, suggesting its superior regional applicability over CAR. The trends in the brightness temperature show the best agreement with the reanalysis data at 500 hPa, as the inter-dataset spread is small. Moderate agreement is seen at 100 hPa, while the highest discrepancies are seen at 250 hPa, as the AMSU-A channel 7 weighting function overlaps the tropical tropopause layer.