Análise da variabilidade e tendência dos extremos de precipitação e a relação com os modos climáticos ENSO & DOI na cidade de Quelimane – Zambézia

Abstract

The Precipitation characterized by high spatio-temporal variability can severely impact human activities, such as agriculture and water supply. Due to the vulnerability of the city of Quelimane to the occurrence of extreme events, this research emerged with the main objective of analyzing the variability and trends of precipitation extremes, especially in relation to the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole climate modes. (DOI). The study had as specific objectives to describe the variability and trends of precipitation extremes in the city of Quelimane, determine the different scenarios of manifestation of the ENSO and DOI climate modes and examine the behavior of precipitation extreme indices in the face of different scenarios of the climate modes. ENSO and DOI. The research used a time series of daily precipitation data from 39 years (1981-2020) obtained at the Quelimane meteorological station, ETCCDI indices and data from the Niño3.4 and DMI climate modes. The results revealed that despite the lack of statistical significance, there was a decreasing trend in accumulated precipitation over time and an increasing number of consecutive days without rain, as well as extreme rainfall. DOI acts as a moderator of ENSO, increasing precipitation during the co-occurrence of positive phases of both and decreasing precipitation when negative phases of ENSO and DOI coincide, compared to isolated ENSO phases. These results indicate alternation of extreme events, such as severe droughts during El Niño and floods in La Niña years, thus justifying the current scenario and projecting intercalations of opposite extreme events. In this context, the research aims to provide data that support effective water and agricultural management policies in the face of the adverse effects of climate variations.