Quantifying and Analyzing Trend Patterns of Rainfall Time Series Data over Baluchistan, Pakistan

Quantifying and Analyzing Trend Patterns of Rainfall

Abstract

There is significant variability in the occurrence of rainfall in different parts of Baluchistan province. In this study, the climatic conditions were analyzed using observed rainfall time series data ranging from 1975-2016 for nine metrological stations in Baluchistan. Mann-Kendal Trend test and Sen’s slope methods were used to find trend and per year change in the rainfall time series of the metrological stations. The methods show that the stations have negative trend and slope values except the stations of Kallat, Nokkundi, and Sibbi. Furthermore, lag-1 autocorrelation method was used to check the serial dependence between the current and lag values of the time series. In the results, the negative values indicate that there is a decreasing tendency of rainfall while the positive values means that rainfall is increasing for the three stations. While only Ormara station has significant decreasing trend using Z-test at 5% level of significance. Similarly, the results show positive lag-1 autocorrelation except only Jiwani station. It means that the current and lag values move in the same direction i.e., decreasing tendency in the overall pattern of rainfall in the area. Hence, it is concluded that Baluchistan is facing a decrease in rainfall amount and the government should make proper arrangements of water resources in the region.