Characterization and prediction of the Mid Summer Drought in the Tempisque river basin, North of Costa Rica, Central America, using ENSO and AMO relationships

Abstract

On the Pacific slope of Central America, the precipitation annual cycle is characterized by two rainfall maxima in June and September-October, an extended dry season from November to May, and a shorter reduced precipitation period during July–August known as Mid-Summer Drought (MSD) or “veranillo”. Four daily gauge stations records, e.g. Nicoya, Santa Cruz, Liberia and Bagaces, located in the Tempisque river basin, province of Guanacaste, North Pacific slope of Costa Rica, were studied to characterize the MSD from 1937 to 2010. Among the aspects considered are the MSD start, end, duration, intensity, deep of the minimum, timing and seasonal predictability. The modulation of these aspects by climate variability sources as Equatorial Eastern Pacific (ENSO) and Atlantic (AMO) was lately explored, including their interannual and decadal variability. The MSD signal strongly impact social and economic life in the region like energy, human consumption and the agriculture sector.