Monitoring anomalies on the large-scale energy and water balance components by coupling remote sensing parameters and gridded weather data

Abstract MODIS images and weather data from 2007 to 2021, were used to monitor the energy balance components and their anomalies, in the Atlantic Forest (AF) and Caatinga (CT) biomes, within a coastal agricultural growing zone, Northeast Brazil. Significant differences on net radiation (Rn) partitions into latent (λE), sensible (H), and ground (G) heat fluxes, promoted distinct vegetation root-zone moisture conditions. The Rn values between the biomes are not significantly different, with annual averages of 9.40 and 9.50 MJ m⁻² d⁻¹, for AF and CT, respectively. However, for respectively AF and CT, the annual average values for λE were 5.10 MJ m⁻² d⁻¹ and 4.00 MJ m⁻² d⁻¹; for H they were 3.80 MJ m⁻² d⁻¹ and 5.00 MJ m⁻² d⁻¹; and for G they were 0.50 MJ m⁻² d⁻¹ and 0.40 MJ m⁻² d⁻¹, yielding respective mean evaporative fraction (Ef = λE/(Rn – G) values of 0.60 and 0.50. Anomalies on λE, H, and Ef were detected by comparing the results for the years 2018 to 2021 with the long-term values from 2007 to each of these years, showing that the energy fluxes between surfaces and the lower atmosphere, and then the root-zone moisture conditions for both biomes, may strongly vary along seasons and years. These assessments are important for water policies as they can picture suitable periods and places for rainfed agriculture as well as the irrigation needs in irrigated agriculture under climate and land-use changes conditions.