Evapotranspiração de canaviais em diferentes fases fenológicas por sensoriamento remoto no vale do submédio do São Francisco.

Abstract

The study aimed to estimate the reference evapotranspiration of sugarcane using the Priestley-Taylor method, comparing with the standard Penman-Monteith-FAO 56 method in the region of the São Francisco Submiddle Valley in the period from 2013 to 2016. Images of the Landsat-8 satellite of the OLI and TIRS sensors acquired from the North American space Agency (NASA) and meteorological data from the Instituto Nacional de Pesquisas Espaciais (INPE) were used, along with the Sistema de Organização Nacional de Dados Ambientais (SONDA) and the Instituto Nacional de Pesquisas Espaciais (INMET). The instantaneous radiation balance, soil heat flow, latent heat flow, crop coefficient (Kc) and Priestley-Taylor coefficient were estimated to obtain the reference evapotranspiration, which ranged from 0.00 to 3.65 mm d-1. The validation proceeded through the correlation between method of crop coefficient applied for Priestley-Taylor and Penman-Monteith. The value of R² 0.75, Pearson coefficient (R) 0.88 (strong correlation) and the mean error found in 1.81 mm d-1 were considered satisfactory. The Priestley-Taylor method was able to estimate the reference evapotranspiration in sugarcane production areas in the region of the São Francisco Submiddle Valley in a satisfactory way.