Abstract
In this study, daily atmospheric radiation and temperature data at the
surface were obtained from the archives of the Modern-Era Retrospective
Analysis for Research and Applications, Version 2 (MERRA-2) for the
period of 36 years (1980 – 2015) over West African geo-climatic
regions. Analyses showed that the values of radiation balance in entire
West Africa decreased from 140.37±2.11W/m2 in 1980 to 132.89±2.18 W/m2
in 2015. This shows that there is dominance of longwave radiation
components in the radiation balance budget which determines the warming
effect in the earth surface. Also, the magnitudes of ratio of change in
surface temperature to change in radiation balance flux (radiative
forcing) termed climate sensitivity ranged between 1.74±0.08 and
3.92±0.69 across the studied regions. These values fall within the
threshold values of 1.5 and 4.5 proposed by the Intergovernmental Panel
on Climate Change (IPCC) Assessment Report for the prevalence of surface
warming. Meanwhile, the trend analyses of frequencies and intensities of
warm nights and warm days whose maximum values were 35.52±0.77 oC and
42.34±0.73 oC showed predominant significant increasing trends
respectively. Also, cross correlation analysis reveals strong
significant relationships between radiation balance flux and temperature
extreme events at short time-lags. Finally, it can be inferred from the
results that the climate system of the West African Region is
experiencing warming effects in which radiation balance contributed
significantly. Consequently, this may result in more heat stress,
drought, and flooding causing negative influences on agriculture,
forestry, and entire ecosystems in this 21st century.