Measurements of net all-wave radiation at a tropical location, Ile-Ife, Nigeria

MURITALA A. AYOOLA, LUKMAN A. SUNMONU, MUNIRU I. BASHIRU, OLUWAGBEMIGA O. JEGEDE

Abstract

Hourly averaged net all-wave radiation data spanning a complete three-year period (2010-2012) at a meteorological station located inside the Obafemi Awolowo University campus in Ile-Ife (7.52º N, 4.52º E), Nigeria is presented in this study to investigate its diurnal and seasonal variations. Using a high-sensitivity four-component net radiometer, the data represents so far the most consistent and detailed information available for a tropical location in West Africa. From the dataset, hourly maxima of the net radiation occurred at 14:00 LT (GMT + 1), whose values increased considerably from 337.6 ± 146.4 Wm–2 in July, which is the peak of the wet season, to 441.7 ± 82.4 Wm–2 in March, the end of the dry season. April and October, both of which mark the beginning and end of the raining season at Ile-Ife have recorded the highest values of 584.7 and 612.2 Wm–2, respectively. There was strong intra/inter-seasonal variation observed in the monthly mean values of the net radiation due mainly to the fluctuations in cloudiness and humidity. In the study area, the data indicated a net radiative heating taking place at the surface, whose annual trend follows a bimodal distribution. The present data supports the results published in earlier studies by other authors.

Keywords

Tropical wet and dry; Ile-Ife; Nigeria; net radiation; bare soil; intra/inter-seasonal variations; radiative heating.

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