Temporal Distribution Characteristics of Alpine Precipitation and Their Vertical Differentiation: A Case Study from the Upper Shule River
State Key Laboratory of Cryospheric Sciences/Division of Hydrology Water-Land Resources in Cold and Arid Regions, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou 730000, China
University of Chinese Academy of Sciences, Beijing 100049, China
Author to whom correspondence should be addressed.
Academic Editor: Xiangzheng Deng
Water 2017, 9(4), 284; https://doi.org/10.3390/w9040284
Received: 27 January 2017 / Revised: 17 April 2017 / Accepted: 17 April 2017 / Published: 19 April 2017
(This article belongs to the Special Issue Sustainable Water Management within Inland River Watershed)
Alpine precipitation is an important component of the mountain hydrological cycle and may also be a determinant of water resources in inland river basins. In this study, based on field observation data of the upper Shule River and daily precipitation records of the Tuole weather station during 2009–2015, temporal distribution characteristics of alpine precipitation and their vertical differentiation were evaluated mainly using percentages of precipitation anomalies (Pa), coefficient of variation (Cv), precipitation concentration degree (PCD) and concentration period (PCP). The results indicated that the inter-annual variability of annual precipitation was generally small, with a Pa that was only somewhat larger in low altitude zones for individual years; the inter-annual fluctuation of monthly precipitation increased noticeably, but the Cv and precipitation can be described as a power function. Annual distribution was basically consistent; more than 85.6% of precipitation was concentrated during the period from May to September; PCD ranged between 0.71 and 0.83 while the PCP was located within the 37th–41st pentads. Diurnal variation of precipitation was defined, mainly occurring from 1500 to 0100 Local Standard Time, and displayed a vertical change that was dominated by precipitation intensity or precipitation frequency. The temporal distribution of alpine precipitation has a noticeable vertical differentiation, and this is likely to originate from the diversity of precipitation mechanisms in mountainous terrain areas.