Precipitation Variations under a Changing Climate from 1961–2015 in the Source Region of the Indus River

Muhammad Rizwan,Youhua Ran,Junaid Nawaz Chauhdary,Xiaoduo Pan,Lubna Anjum,Xin Li,Kashif Jamal,Donghai Zheng,Yingying Chen

doi:10.3390/w11071366

Abstract

The source region of the Indus River (SRIR), which is located in the Hindukush, Karakoram and Himalayan (HKH) mountainous range and on the Third Pole (TP), is very sensitive to climate change, especially precipitation changes, because of its multifarious orography and fragile ecosystem. Climate changes in the SRIR also have important impacts on social and economic development, as well as on the ecosystems of the downstream irrigation areas in Pakistan. This paper investigates the changes in precipitation characteristics by dividing the daily precipitation rate into different classes, such as light (0–10 mm), moderate (10.1–25 mm) and heavy precipitation (>25 mm). Daily precipitation data from gauging and non-gauging stations from 1961–2015 are used. The results of the analysis of the annual precipitation and rainy day trends show significant (p < 0.05) increases and decreases, respectively, while light and heavy precipitation show significant decreasing and increasing trends, respectively. The analysis of the precipitation characteristics shows that light precipitation has the highest number of rainy days compared to moderate or heavy precipitation. The analysis of the seasonal precipitation trends shows that only 18 stations have significant increasing trends in winter precipitation, while 27 stations have significant increasing trends in summer precipitation. Both short and long droughts exhibit increasing trends, which indicates that the Indus Basin will suffer from water shortages for agriculture. The results of this study could help policymakers cope with floods and droughts and sustain eco-environmental resources in the study area.

Highlights

The Indus Basin is among the world’s largest transboundary river basins
This study focused on characteristics and trends in precipitation and was carried out in the source region of the Indus River (SRIR)
The SRIR is a transboundary basin, the major part of which is in Pakistan, followed by India, China, and Afghanistan

Summary

Introduction

The Indus Basin is among the world’s largest transboundary river basins. The southern part of this basin has subtropical arid and semiarid to temperate subhumid climates on the plains of Punjab and Sindh provinces, while the northern part has high-altitude mountainous highlands with humid climatic conditions. The upper part of this basin is the source region of the Indus River (SRIR). The SRIR is situated on three of the world’s largest mountain ranges, i.e., the Hindukush, Karakoram and Himalayan (HKH) ranges and in the Third Pole (TP) region. The changing climate in the SRIR has accelerated the melting of glaciers, which has caused a higher contribution of snowmelt than precipitation in stream flow, which was confirmed by Immerzeel, Van Beek [4] via an investigation of the observed annual mean discharge from 2001 to 2005. The largest portion of the stream flow received at the Tarbela Dam on the Indus River comes from the melting of snow and glaciers in the Upper Indus River basin [7,8,9]. Due to the westerly disturbances, maximum precipitation occurs during the winter and spring seasons in the SRIR [10,11]

Methods

Results

Conclusion