Investigation Of The Surface Energy Budget At Nimex_3 Site, Ibadan Using Bowen Ratio Energy Balance Method
Keywords:
Sensible Heat Fluxes, Latent Heat Fluxes, Bowen RatioAbstract
The surface energy budget measures the atmospheric turbulent fluxes and the interaction of heat exchange between land surface and atmosphere. The sensible (QH) and latent heat flux (QE) densities were computed using Bowen Ratio Energy Balance (BREB) for Nigeria Meteorological Experiment (NIMEX_3) site situated in University of Ibadan. The study examined 50days of data sets consisting of net radiation, wind speed, pressure, soil heat flux and air temperature measured at levels 6m and 12m. The daily calculated QH and QE range between 7.30 Wm-2 to 47.01 Wm-2, and 20.98 Wm-2 to 184.57 Wm-2 respectively. The BREB estimation of the sum of QH and QE with day-time surface available energy revealed that the energy budget closure varied closely to 100%, and the ratio of the residuum to available energy indicates that there was no imbalance in surface energy budget for the site. The Bowen ratio latent heat fluxes are higher than sensible heat fluxes during the daytime. Furthermore, BREB method partitioned energy fluxes differently favouring latent heat flux. Consequently, the diurnal variations of the surface energy fluxes for the periods under considerations correspond to the periods of higher closure ratio. The analyses revealed irregular variations of Bowen Ratio for the Julian Days 51-100 which are consistent with the daily variation of the weather conditions of air masses and moisture transfer. The result of this study could be used to determine surface energy budget closure over Tropical stations.
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