Effect of the radiation balance on warming occurrence over West Africa

Abstract

In this study, hourly atmospheric radiation and surface temperature data were taken from the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) database for the period of 36 years (1980–2015) in the West African region. The main objective of the research is to study the effect of the radiation balance on the warming scenario in West Africa. The research deduced the warming scenario from extreme weather events referred to as warm nights and hot days. The severity of the warming event was measured using the methods of climate sensitivity and trend. The effect of the radiation balance on the warming event was evaluated using a cross-correlation technique. Analyses showed a decrease from 140.37±2.11 W/m2 in 1980 to 132.89±2.18 W/m2 in 2015 in the average annual radiation balance in West Africa as a whole. This shows that the radiation balance budget has dominant long-wave radiation components that determine the warming effect on the surface of the earth. Also, the values of the sensitivity of the climate were observed between 1.74±0.08 and 3.92±0.69 in the studied regions. Meanwhile, the Intergovernmental Panel on Climate Change (IPCC) assessment study on the occurrence of surface warming sets these values between 1.5 and 4.5 threshold values. Furthermore, prevailing significant increasing trends were observed for warm nights and warm days temperatures with the highest values of 35.52±0.77 C and 42.34±0.73 °C respectively over the whole West African Region. Besides, the cross-correlation analysis showed that net radiation was related to extreme temperatures at a short response time with a strong correlation. Lastly, the findings indicate that the radiation balance has a significant contribution to the warming of the West African climate system. This will consequently lead to increased thermal stress, drought, and floods which could have adverse effects on agriculture, biodiversity, and ecosystems as a whole in the 21st century.