Evaluation of Phase Discrimination Methods and Snow Fraction Perturbations in Arid Regions of Northwest China
Evaluation of Phase Discrimination Methods and Snow Fraction Perturbations in Arid Regions of Northwest China
复制标题
西北干旱区鉴相方法与雪分数扰动评价
DOI：
10.1175/jhm-d-20-0118.1
复制
发表时间：
2020-11
影响因子：
3.8
通讯作者：
XIAOHUA CHEN
中科院分区：
文献类型：
--
作者：
MUATTAR SAYDI;GUOPING TANG;YAN QIN;HONG FANG;XIAOHUA CHEN
积雪比例对干旱地区的水资源有着直接影响。因此，选择合适的估算积雪比例的方法至关重要。对两种基于温度和两种基于湿度的判别降水相态的方法进行了评估。
Snow fraction has a direct impact on water resources in arid regions. The selection of proper methods for estimating snow fraction is thus essential. Two temperature-based and two humidity-based approaches to discriminate precipitation phase were evaluated using daily meteorological observations over the past six decades in Xinjiang in arid northwest China. The main findings included that 1) the finest discrimination was achieved by the wet-bulb temperature (Tw) method whereas the single temperature threshold at 0°C produces the poorest result; the performances of the Dai and humidity-dependent empirical method (TRH) methods were between them, with slightly lower error using the Dai method. Also, the Tw method is the least sensitive to regional heterogeneity and less affected by distinct changes in elevation; the other three methods, however, are biased mostly toward underestimating snow and show larger variations due to the regional discrepancies. Careful adjustment of snow discrimination thresholds based on the local properties of observation spots is needed for these methods. 2) Despite widespread warming, snow fraction perturbations in Xinjiang are characterized mainly by insignificant changes plus pronounced reductions at high mountain sites. Proxy drivers of such changes can be better explained by considering the hydrothermal diversity and changing climatic factors. Across the wetter subregions, snowfall has been significantly increasing, and the positive impact of which on snow fraction was hindered by significant warming, particularly in winter, and summer rainfall; across the drier subregions, however, insignificant change in snow fraction corresponds to a slow and insignificant increase in snowfall joined by the negative impacts of significant winter warming and summer rainfall.