Trend Analysis of Annual and Seasonal River Runoff by Using Innovative Trend Analysis with Significant Test

Yilinuer Alifujiang,Yongxiao Ge,Jilili Abuduwaili

doi:10.3390/w13010095

Abstract

This study investigated the temporal patterns of annual and seasonal river runoff data at 13 hydrological stations in the Lake Issyk-Kul basin, Central Asia. The temporal trends were analyzed using the innovative trend analysis (ITA) method with significance testing. The ITA method results were compared with the Mann-Kendall (MK) trend test at a 95% confidence level. The comparison results revealed that the ITA method could effectively identify the trends detected by the MK trend test. Specifically, the MK test found that the time series percentage decreased from 46.15% in the north to 25.64% in the south, while the ITA method revealed a similar rate of decrease, from 39.2% to 29.4%. According to the temporal distribution of the MK test, significantly increasing (decreasing) trends were observed in 5 (0), 6 (2), 4 (3), 8 (0), and 8 (1) time series in annual, spring, summer, autumn, and winter river runoff data. At the same time, the ITA method detected significant trends in 7 (1), 9 (3), 6(3), 9 (3), and 8 (2) time series in the study area. As for the ITA method, the “peak” values of 24 time series (26.97%) exhibited increasing patterns, 25 time series (28.09%) displayed increasing patterns for “low” values, and 40 time series (44.94%) showed increasing patterns for “medium” values. According to the “low”, “medium”, and “peak” values, five time series (33.33%), seven time series (46.67%), and three time series (20%) manifested decreasing trends, respectively. These results detailed the patterns of annual and seasonal river runoff data series by evaluating “low”, “medium”, and “peak” values.

Highlights

Climate change affects regional water resources [1]
These results indicate that the river runoff in spring and autumn generally exhibits positive skewness, and the annual river4runoff
These results show that the magnitudes of the trends at most of the selected river stations were positive and varied from 0.001–0.031 m3 /s

Summary

Introduction

Climate change affects regional water resources [1]. As a unique geographic component, the mountain area is the birthplace of most rivers in arid regions. Central Asia’s water resources are mainly recharged by melting ice and snow in the mountainous areas, making them more sensitive to climate change [6,7,8]. The river runoff is one of the primary forms and components of water resources and the most critical water source for production and living [11,12]. Affected by climate variability and anthropogenic activities, the river runoff of many rivers worldwide has undergone significant changes, seriously threatening the state of regional water resources [13,14,15,16,17,18]

Methods

Results

Conclusion