Análise de índices de detecção de mudanças climáticas na bacia hidrográfica do Rio Colorado - EUA.

Abstract

The present study aimed to analyze the trend of extreme indices of annual air temperature and precipitation in the Colorado River Watershed (BHRC) located in the southwest of the USA from 1970 to 2009, as well as to correlate them with SST anomalies in the Atlantic and Pacific Oceans and with teleconnection rates. Air temperature and rainfall data were obtained from meteorological stations distributed throughout the American states that make up the BHRC. To analyze the behavior of annual SST anomalies in the oceans and their influence on the annual climate extremes in the studied region, the RCIimdex software was used to obtain the trends of climate extremes and the Pearson method for the correlations between the annual anomalies of TSM and the indices of climatic extremes obtained. The results show that the DV index contributed to warmer days in practically the entire region. The NT index predominated in the region of Baixo Colorado. Cold days have reduced throughout the basin region. The minimum values ​​of maximum and minimum temperatures increased the maximum values ​​of maximum and minimum temperatures did not indicate variability. Regarding precipitation, it was observed that the extremes in the Lower Colorado region showed trends, mostly negative, unlike the Upper Colorado River. As there were few statistically significant trends, the extremes of precipitation did not show well-defined patterns in the BHRC The connotations of air temperature indices with TSM anomalies and teleconnection indices indicated greater contribution of PDO, AMO and PNA on the two regions analyzed in the Colorado River basin. The positive anomalies of SST contributed to the increase in temperatures in the region. Regarding precipitation, there was a better relationship between its extreme indices with PDG and PNA.