CLIMATE CHANGE IMPACTS ON WATER DEMAND OF MELON PLANTS IN JAGUARIBE-APODI REGION, BRAZIL

ABSTRACT The aim of this study was to evaluate the impacts of climate change on irrigation water demand of melon plants grown in Jaguaribe-Apodi Irrigation District (DIJA), which is located between the states of Ceará and Rio Grande do Norte, in Northeastern Brazil. Future scenarios were developed using the Eta-CPTEC/HadCM3 climate change projections, after being submitted to downscaling method. We used a set of climate data from the same model for the period of 1961 through 1990, and further projections after bias correction. Local geographic coordinates were interpolated using GIS techniques. Reference evapotranspiration (ETo) was estimated from the monthly minimum and maximum mean temperatures, using a limited data method. The rainfall, temperature, ETo, and water demand future projections were mapped for the area of investigation to analyze spatial variability. ETA model simulations for climatic change showed growth in irrigation water demands due to evapotranspiration increase (from 28.4% to 33.4%), even though rainfall increases (between 61.9% and 89.9%). The increase in the average gross water demand is varied from 37.5% to 78.2% within the period of 2031 to 2060, respective to the common planting season.