Análise dos índices de precipitação e temperatura do ar da Amazônia Ocidental e influências de oscilações climáticas de escala global.

Abstract

The objective of this research was to investigate the possible influence of the Oscillation: Pacific Decadal (PDO), Multidecadal Atlantic (AMO), North Atlantic (NAO), Quasi-Biennial (QBO), Pacific North American (PNA) and indices of Sea Surface Temperature (SST) anomalies in the equatorial Pacific and the tropical Atlantic on the indices of climate extremes in precipitation and air temperature in the Western Amazon. We used indices: total annual precipitation (PRCPTOT); simple index of daily rainfall intensity (SDII); consecutive dry days (DCS) and consecutive wet days (DCM), based on rainfall, maximum temperature and maximum (TXx), minimum maximum temperature (TXn); maximum temperature minimum (TNx) and minimum temperature minimum (TNn), based on air temperature. They were extracted from the data reanalysis ERA-40 during 1970-2001. We determined the spatial and temporal homogeneous regions of climate indices using principal component analysis and grouping patterns. It was found that the indices of temperature show two homogeneous regions on the western Amazon, and precipitation from three to six. The indices of climate extremes of precipitation and air temperature showed statistically significant correlations with the DPO, AMO and NAO. We conclude that these teleconnections somehow modulate the interannual variability of precipitation and temperature in the Western Amazon. The indices of temperature and precipitation are also influenced by SST anomalies in the tropical Atlantic, especially the northern sector. The SST anomalies in the areas of Niños, especially 3.4 and 4 and indices of PRCPTOT, SDII and DCM showed positive and negative correlations in the western sector in the eastern sector of the Western Amazon .The correlation with the index DCS presented inverted signal. This result shows that the east region has a relationship with the El Niño / La Niña similar to Northeast Brazil and eastern Amazonia, while the west with the Andes. Positive SST anomalies in the equatorial Pacific can produce increased rates of temperature decrease and negative anomalies. The minimum temperature showed minimal decay trend, possibly associated with human factors and the maximum of maximum upward trend, probably due to anthropogenic and natural factors, since the study was conducted in the positive phase of the PDO.