Innovative trend analysis of annual and seasonal precipitation in Ningxia, China

Abstract

Based on daily rainfall data from 26 station records, spatial and temporal variations in annual and seasonal precipitation of different rainfall intensities from 1961 to 2018 in Ningxia, China are investigated using the innovative trend analysis (ITA) method. The results show that annual precipitation increases on the northern plain but decreases in the southern mountainous area. The increase in regional annual precipitation is mainly due to an increase in weak precipitation, while the decrease in regional annual rainfall is a result of a reduction in heavy precipitation. Low-intensity precipitation shows an upward trend, while high-intensity precipitation shows a downward trend. The variation trend of extreme precipitation is more obvious. The contributions of different types of extreme precipitation vary by season. During spring, the increase in regional rainfall is mainly caused by the increase in heavy precipitation, while the decrease in regional precipitation is mainly caused by the decrease in weak precipitation. During summer and autumn, the increase in regional precipitation is caused by the increase in light precipitation, while the reduction in regional rainfall is caused by the decrease in heavy precipitation. This study provides support for water resources planning and addressing droughts and floods.