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

Abstract

RESUMENSe presentan datos de radiación neta en todas las longitudes de onda promediados cada hora, registrados en una estación meteorológica situada en el campus de la Universidad Obafemi Awolowo, Ile-Ife (7.52º N, 4.52º E), Nigeria, durante un periodo completo de tres años (2010)(2011)(2012), para estudiar sus variaciones diurnas y estacionales. Esta información, obtenida con un radiómetro neto de alta sensibilidad de cuatro componentes, representa hasta hoy la información más consistente y detallada disponible para una localidad tropical de África Occidental. De acuerdo con los datos obtenidos, la radiación neta máxima ocurrió a las 14:00 LT (GMT + 1), y sus valores se incrementaron de manera considerable de 337.6 ± 146.4 Wm -2 en julio, que es el pico de la estación lluviosa, a 441.7 ± 82.4 Wm -2 durante marzo, en el final de la estación seca. En los meses de abril y octubre, que marcan el principio y fin de la estación lluviosa en Ile-Ife, se han registrado los valores más altos de radiación neta: 584.7 y 612.2 Wm -2 , respectivamente. Se observó una importante variación inter e intraestacional en los valores medios mensuales de radiación neta, debida principalmente a fluctuaciones de nubosidad y humedad. En el área de estudio, los datos revelaron la presencia de calentamiento radiativo neto en la superficie, cuya tendencia anual sigue una distribución bimodal. Los datos de este estudio respaldan los aportados por otros autores. ABSTRACTHourly 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.

Diurnal variation of carbon dioxide flux above growing cowpea (<i>Vigna unguiculata [L] Walp.</i>) at an agricultural site in Ile-Ife, Nigeria

“…ms (Jegede et al, 1997;Ayoola et al, 2014). It has a dimension approximated 1500 m by 300 m. Typical varieties of arable crops; such as maize, cassava, water melon and fruits are planted every year and the area is characterized with a few scattered trees.…”

Evaluation and Calibration of Downward Longwave Radiation Models under Cloudless Sky at Ile-Ife, Nigeria

“…This intersection migrates and attains its most northerly position between 22.25°N in August (Okogbue, 1997 (Okogbue, 1997;Falaiye, Babatunde and Willoughby, 2014;Soneye, 2018). In this area, the sunrise time and sunset time are around 07:00 LT and 19:00 LT respectively (Ayoola et al, 2014;Soneye et al, 2019) while the yearly average air temperature and relative humidity are about 26.7 °C and 80.1 % respectively. Mean yearly rainfall ranges between 1000 and 1500 mm with weak surface wind flow less than 1.5 ms -1 (Hayward and Oguntoyinbo, 1987;Ayoola et al, 2014;Soneye et al, 2019).…”

“…March/April to October and November to February, respectively (Griffiths, 1974;Ayoola et al, 2014;Soneye et al, 2019). In this area, variations and changes in the pattern of the season are as a result of the meridional (North -South) movement of the Inter-Tropical Convergence Zone (ITCZ) across West Africa.…”

Parameterization of net radiation in an arid city of northwestern Mexico

“…Net radiation is a fundamental driver of climate in the lower layers of the atmosphere, and its effects depend on both the structure and composition of the atmosphere and the presence of clouds, in addition to surface characteristics such as albedo, emissivity, temperature, moisture and the thermal properties of underlying soil (Kessler and Jaeger, 1999). It is also the driving force for many physical, dynamic, and biological processes, including warming of the soil and air, photosynthesis, and evapotranspiration, the latter being important for the quality and yield of crops and the planning of water resources (Bennie et al, 2008;Ji et al, 2009;Li et al, 2009;Geraldo-Ferreira et al, 2011;Ayoola, 2014).…”