Obtenção do saldo de radiação por imagens multiespectrais no Perímetro Irrigado de São Gonçalo – PB e Estação Ecológica do Seridó – RN.

Abstract

The radiation balance represents the main source of energy used by the chemical, physical, biological and meteorological processes in the surface and in the lower layers of the atmosphere. The balance of radiation and its components (incident ad reflected of long wave and shortwave radiation) have applications in agriculture, hydrology, renewable energies and climate research. Therefore, the aim of this study is to estimate the instantaneous radiation balance – Rn,ins and daily – Rn,24h of the irrigated perimeter of São Gonçalo, Tower Micrometeorological-RN and surrounding areas with different types of use and occupation in the Brazilian semi-arid, for the years 2015 and 2016, using OLI/TIRS-Landsat 8 images and MODIS/TERRA products. The MODIS products used in the research were MOD09GA (reflectance and sun angle), MOD09GQ (reflectance) and MOD11A1 (surfasse temperature, time of satellite passage) with resolutions of 250m and 500m. Images without the presence of clouds from the years 2015 and 2016 were selected, with 9 17 images from the OLI/TIRS Landsat-8 satellite and 79 and 61 from the MODIS products, for mentioned years of study. The validation of the results was performed with data from a micrometeorological tower, located in na área of preserved caatinga, located in the city of Serra Negra do Norte, RN in the Seridó Ecological Station (ESEC-ICMBio). The values of albedo and instantaneous radiation balance with resolution of 250m provided more satisfying results than the albedo and radiation balance calculated by the Landsat 8 images. It should be noted, therefore, that the daily radiation balance presented a better result with Landsat OLI / TIRS images 8 compared to those obtained by MODIS at resolutions of 250 m and 500 m for both years.