The impact of climate indices on precipitation variability in Baluchistan, Pakistan

Pakistan’s biggest province in terms of area, Baluchistan appears to have been affected from the climate variability since last few decades. No substantive research works have been carried out in analyzing the precipitation variability in Baluchistan and linkage to large-scale teleconnection. The goal of this paper is to determine possible linkages of precipitation with large scale atmospheric and oceanic circulation indices in the months which have shown changes in precipitation trends in Baluchistan. These climate indices may be the possible predictors for the precipitation in Baluchistan in the respective months. Mann-Kendall (MK) statistical test was used to identify the monthly significant precipitation trends in thirteen meteorological stations located in four regions of Baluchistan. The noteworthy trend out of significant trends is selected using Theil and Sen’s slope (TS). Decreasing trend is identified in January whereas increasing trend is identified in June mostly in stations located in North Eastern region of Baluchistan (Region1). The changes in the significant trend in January and June under the influence of climate indices are then determined by Partial Mann-Kendall (PMK). Empirical Orthogonal Function (EOF), Principal Component Analysis (PCA), correlation technique between Principal Components (PC) of Region1 precipitation and climatic Indices are used to filter out the relevant climatic indices. It is found out that North Atlantic Oscillation (NAO), Equatorial Indian Ocean Zonal Wind Index (EQWIN), ENSO Modoki Index (EMI) on annual scale whereas Pacific Decadal Oscillation (PDO), Atlantic Multi-decadal Oscillation (AMO) on decadal scale are influencing the January precipitation. It is also found out that El Nino Southern Oscillation-Multivariate ENSO Index (ENSO-MEI), EMI, NAO, PDO and AMO are influencing the June precipitation. These are the dominating indices explains the precipitation variability in January and June in this Region1. This research will impart awareness in the society from the impact of precipitation trend variability.