Índices de monitoramento e detecção de mudanças climáticas na região Centro-Oeste do Brasil.

Abstract

The objective of this study was to estimate the indexes of detection and monitoring of climate change, dependent on daily precipitation and daily temperature, defined by WMO for Midwest region of Brazil. Furthermore, was analyzed the possible changes in time scales annual and seasonal and introduced two new indexes based on relative humidity. For reach the objectives were used daily precipitation, daily temperature ((maximum and minimum) and relative humidity (observed the 18 UTC- Universal Coordinated Time) from the National Institute of Meteorology (INMET) of thirty-three conventional station located in the states of Goiás, Mato Grosso, Mato Grosso do Sul, Sao Paulo, Tocantins and Minas Gerais. The data showed reliable quality and cover the entire study area. The results shown by the two new indexes of climate change based on relative humidity showed that annually, the Midwest region has the greatest number of days (UR30) and periods (DCUR30) with relative humidity below 30%. Seasonally, this same pattern was observed in winter (season climatologically dry season in the region) and spring (season that corresponds to the transition between the end of the dry season and early rainy season). In relation to indexes based on daily maximum and minimum temperatures, they generally showed homogeneous spatial distribution of the trends positive/negative (increase/decrease). And most of them, there was much annually as seasonal rise in minimum and maximum temperatures in the region. On the other hand, the indexes based on daily precipitation didn’t show a homogeneous pattern of spatial distribution of trends. Annually, only the indexes PRCPTOT, R10, R20, R95p, R99p and RX1day showed a predominance of positive trends (increase) in most of the study area. Seasonally, it was observed in the autumn that only the indexes CDD, PRCPTOT, RX1day and RX5day present trends of rising in much of the area's Midwest region.