BALANCE OF RADIATION BY REMOTE SENSING OVER THE HYDROGRAPHIC BASIN OF NORTHEASTERN MATA ZONE

This study aimed to determine the radiation balance in the basin of Tapacurá river - PE, an area with intense presence of cloudiness, through MODIS products of Terra satellites (MOD09GA and MOD11A1) and Aqua (MYD11A1 and MYD09GA). For the in situ balance radiation calculation and for the monitoring of meteorological data required for radiation balance processing, a weather station was installed and operated during the experimental period from January/2010 to August/2011. The instantaneous net radiation estimated with MODIS products were between 400 and 700 W m^-2, the higher values were recorded in the Tapacurá reservoir and the smaller on urban areas. The estimated daily net radiation ranged from 95.4 to 157.5 W m^-2, with an average of 125.4 W m^-2. The differences between the net radiation measured at the experimental station (grazing area) and estimated by MODIS products, resulted in Mean Absolute Difference, Mean Relative Difference and Root Mean Squared Difference values of 122.4 W m^-2, 30, 1% and 140.7 W m^-2 respectively for the instantaneous net radiation, and 7.4 W m^-2, 5.8% and 9.7 W m^-2 for the daily net radiation. It is concluded that despite the intense presence of clouds in the region it was possible to obtain the balance radiation on the Tapacurá River Basin - PE by MODIS based products, consistent with other studies results, confirming the efficiency on the technique applicability.

solar radiation; MODIS; albedo; net radiation.