Possible Causes for Spatial and Temporal Variation of Warm Season Precipitation in Xinjiang from 1960–2014

Shikai Song,Aixia Yang,Zhaolei Zong,Jianli Ding,Geping Luo

doi:10.3390/atmos8010020

Abstract

In this work, rain totals from 1960–2014, obtained during the warm season (May to October) from 52 meteorological stations, over Xinjiang, China were classified as either light, moderate, or heavy rain in two sub-regions (northern and southern). Spatial and temporal trends for rain amounts and days for the three rain classes were determined. All light, moderate, and heavy rain amounts displayed increasing trends over the two sub-regions. Furthermore, heavy rain amounts contributed the most to changes in total rain amounts. Light rain days in northern Xinjiang significantly decreased, in contrast to increasing light rain days in southern Xinjiang and moderate and heavy rain days within two sub-regions. Results obtained from correlation and relative weights analyses implied that lower-tropospheric specific humidity was the main factor responsible for light rain day trends in Xinjiang. Increasing temperatures were not found to have a significant effect.

Highlights

In Xinjiang, the most arid region in China, precipitation is a critical water source for both human livelihoods and ecosystems
Extreme precipitation is defined as annual total precipitation with daily precipitation > 95th percentile, named P95, which is one of the thirteen extreme precipitation indices introduced by the ETCCDI [10,11]
Lower-tropospheric specific humidity (SH) were, determined to be positively correlated with light rain days over the entire region of Xinjiang, with correlation coefficients ranging from 0 to 0.8, and significance over most of the region of Xinjiang (Figure 6c). These results indicated a close relationship between SH and light rain days

Summary

Introduction

In Xinjiang, the most arid region in China, precipitation is a critical water source for both human livelihoods and ecosystems. Tremendous significance has been imparted to the study of precipitation variations. Global mean annual precipitation has exhibited increasing trends that are thought to be related to global warming [1,2,3,4]. In the context of global warming, a good understanding of precipitation variations over Xinjiang is essential for hydrology, climatology, and ecology research. A significant increasing trend in annual precipitation, with rates of 0.4–0.5 mm·year−1 across Xinjiang, have been documented [5,6,7,8,9]. Studies have noted variations in extreme precipitation that may lead to local flooding over short periods of time, resulting in tremendous economic loss. Extreme precipitation is defined as annual total precipitation with daily precipitation > 95th percentile, named P95, which is one of the thirteen extreme precipitation indices introduced by the ETCCDI (the Expert Team on Climate Change Detection and Indices) [10,11]

Methods

Results

Conclusion