Trend analysis of precipitation for protected areas and pasturelands in southwest Amazônia between 1998 and 2019

Abstract

This article presents a spatio-temporal analysis of the rainfall distribution for the State of Rondônia. Data from the Tropical Rainfall Measurement Mission were analyzed, comprising a time series from 1998 to 2019. Data obtained from remote sensing were validated with data collected from rainfall stations. Trend analyzes were developed by applying the Mann-Kendall test. The spatialization of the increase and decrease of precipitation for the state was performed using the slope method of Sen. The rainfall stations showed a percentage of underestimation of −66%, an average standard error of 156.8 mm.year−1 an average correlation (r) of 0.66, indicating an average degree of agreement (d) equivalent to 0.68. The decrease in annual precipitation occurs mainly in the north of the state. For the dry season, protected areas again showed a smaller reduction than unprotected areas. Protected areas showed a reduction of 6 mm.year−1 while unprotected areas showed a reduction of 8 mm.year−1, also in the north of the state. According to the TRMM data obtained from remote sensing, a reduction of approximately 1.5 mm.year−1 can be seen, mainly in the northern region of the state of Rondônia, which has extensive areas of conversion of native forest to pasture and an increase in approximately 1 mm.year−1 in the southwest region of the state, which has the largest extension of protected natural areas.