Precipitation-type discrimination and changes in related climate indices in the upper Heihe River Basin during 1960–2021

Frontiers in Environmental Science

Environmental Science

Xiong Xiao¹  Guanxing Wang²  Li Wang³  Fan Zhang³  Xiaonan Shi³  Chen Zeng³ 

[1] College of Geographic Science, Hunan Normal University, Changsha, China;Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation, College of Geographical Science, Qinghai Normal University, Xining, China;Qinghai Province Key Laboratory of Physical Geography and Environmental Process, College of Geographical Science, Qinghai Normal University, Xining, China;State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China;State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China;University of Chinese Academy of Sciences, Beijing, China;

关键词: precipitation-type discrimination;    threshold temperature;    climate change;    extreme rainfall;    the upper Heihe River Basin;    the Tibetan Plateau;   

DOI  :  10.3389/fenvs.2023.1202895

 received in 2023-04-09, accepted in 2023-05-24,  发布年份 2023

来源: Frontiers

【 摘 要 】

Introduction: Precipitation in the upstream region of the Heihe River basin (UHRB) in the northeastern of the Tibetan Plateau, which is the main water source of the basin, has undergone drastic changes in extreme climate events in recent decades. In addition to the amount of precipitation, the type of precipitation has a substantial impact on hydrological processes.Methods: In this study, we compared the results from three methods aimed at improving precipitation type estimation based on daily precipitation type records for 24 discontinuous years. Based on the precipitation type distinction, we examined the spatial and temporal changes in the total precipitation, rainfall, snowfall and air temperature at the six stations as well as the spatial average of the UHRB during the past 62 years. We also analyzed changes in the quantity, duration magnitude, and frequency of extreme precipitation using the RClimDex model and statistical analysis.Results: The probability of detection value of the T3.6_4.5 method was 1.9%, indicating the estimation was closest to actual records. The analyses based on precipitation type diving showed that rainfall accounts for an average of 81.9% of the total precipitation received in a year. In the context of large scale climate warming, temperatures at all six stations increased significantly, but precipitation changes were only apparent at about half of the stations which were located in regions of higher elevation and influenced by both ENSO and the East Asian monsoon. Analysis of the spatial averages in the UHRB revealed that the annual drought events (CDD) were significantly alleviated, and that the growing season length (GSL) was significantly extended. The annual total precipitation, rainfall, and extreme precipitation indices (P99P, P95P, R95P, and SDII) increased in magnitude, and the frequency of extreme precipitation events (P10mm) also significantly increased.Discussion: The findings of this study indicate that under the background of climate warming, the changes of precipitation patterns in the UHRB which may have resulted in bringing better vegetation growth, but also the increasingly frequent extreme rainfall events may pose challenges to growing extreme rainfall events to agriculture and other human activities in local and downstream areas.

【 授权许可】

Unknown   
Copyright © 2023 Wang, Zhang, Wang, Zeng, Shi and Xiao.