侯志康, 许民, 康世昌, 韩海东, 王鹏寿, 李振中, 张溪. 中国西北地区降水相态分离及其变化分析[J]. 农业工程学报, 2023, 39(8): 120-132. DOI: 10.11975/j.issn.1002-6819.202302008
    引用本文: 侯志康, 许民, 康世昌, 韩海东, 王鹏寿, 李振中, 张溪. 中国西北地区降水相态分离及其变化分析[J]. 农业工程学报, 2023, 39(8): 120-132. DOI: 10.11975/j.issn.1002-6819.202302008
    HOU Zhikang, XU Min, KANG Shichang, HAN Haidong, WANG Pengshou, LI Zhenzhong, ZHANG Xi. Separation and variation of precipitation forms in Northwest China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(8): 120-132. DOI: 10.11975/j.issn.1002-6819.202302008
    Citation: HOU Zhikang, XU Min, KANG Shichang, HAN Haidong, WANG Pengshou, LI Zhenzhong, ZHANG Xi. Separation and variation of precipitation forms in Northwest China[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2023, 39(8): 120-132. DOI: 10.11975/j.issn.1002-6819.202302008

    中国西北地区降水相态分离及其变化分析

    Separation and variation of precipitation forms in Northwest China

    • 摘要: 降水相态的转变会对中国西北地区水资源、生态环境和农业生产活动产生非常重要的影响。为明确中国西北地区降水相态转变规律,该研究基于西北地区1961-2017年国家气象站观测的日降水、气温、相对湿度、大气压以及站点高程数据,利用湿球温度动态阈值模型对降雪和降雨进行分离,并对分离结果精度进行验证;基于此分析了区域不同相态降水的时空变化特征,探讨了雨雪分离阈值变化及降水相态的影响因素。结果表明:1961-2017年西北地区不同相态的降水量均呈显著增加趋势,降雨量的增加速率为9.80 mm/10 a,降雪量的增加速率为1.07 mm/10 a,雪雨比呈不显著减少趋势,减少速率为0.07%/10 a。但空间变化趋势具有区域差异性,总体表现为"西增东减"。西北地区极端降雪量的显著增加导致了降雪量的显著增加,而总降雪日数趋势变化不显著,主因是小雪日数的显著减少和极端降雪日数的显著增加共同所致,小雪日数的下降速率为0.25 d/10 a,极端降雪日数的增加速率为0.12 d/10 a。雨雪分离的阈值温度在年内波动较大,年际总体呈现不显著的下降趋势,临界高温和临界低温的下降速率分别为6′10-4、7′10-4 ℃/10 a,且在2008年发生突变。在流域尺度上,各相态降水变化速率随着海拔升高而升高,雪雨比则相反;降雪量的变化主要受气温和相对湿度影响,雪雨比的变化主要受气温影响。该研究对深入认识西北地区气候暖湿化背景下的水资源变化具有重要意义。

       

      Abstract: Abstract: Fragile ecological environment and shortage of water resources in Northwest China have seriously affected agricultural and economic development. Among them, the precipitation form can be one of the most important factors in the water cycle in the northwest arid region. The changes in precipitation forms can be of great significance to determining the water resources change in the background of climate warming-wetting trend in northwest China. In this study, the wet bulb temperature dynamic threshold model was established to separate the snowfall and rainfall using the daily precipitation, air temperature, relative humidity, atmospheric pressure, and station altitude data observed by the National Meteorological Station in northwest China during 1961-2017. The accuracy of the separation was also validated. A systematic analysis was made on the temporal and spatial variation characteristics of precipitation, rainfall, snowfall, and S/R in the region. Furthermore, the regional differences of precipitation in different forms and the S/R ratio were determined on the spatial scale of the secondary basin. The snowfall was divided into four types, in order to analyze the change characteristics of different types of snowfall. An investigation was implemented to explore the changes in snowfall and rainfall separation threshold and the influencing factors of precipitation forms. The results show that the precipitation in different forms in Northwest China showed a significant increasing trend during 1961-2017. However, the increasing trend of rainfall was more outstanding than that of snowfall. The Snowfall/Rainfall ratio showed a non-significant decreasing trend, with a decrease of 0.07%/10a. The spatial variation trend shared the outstanding regional differences with an "increase in the west and decrease in the east", and the distribution of regions with the outstanding increase was concentrated in the central region of the northern Xinjiang and Hexi Corridor. The Snowfall/Rainfall ratio is distributed with "an increase in the west and decrease in the east", and "increase in the north and decrease in the south". The significant increase of extreme snowfall in Northwest China led to a significant increase of snowfall, with an increase of 1.07 mm/10a. Specifically, the increased rate of extreme snowfall was 1.03 mm/10 a. On the contrary, there was a more outstandingly decreasing trend in light snowfall and moderate snowfall. The slight decreasing trend of snowfall days was mainly caused by the significant reduction of light snowfall days and the significant increase of extreme snowfall days. By contrast, there was no change in moderate snowfall days and heavy snowfall days. The threshold temperature of snowfall and rainfall separation fluctuated greatly on a seasonal scale, with the highest threshold temperature in autumn, the second in winter, and the lowest in spring. The change in relative humidity caused the change in threshold temperature. Furthermore, the higher the relative humidity was, the greater the threshold temperature difference was. On the interannual scale, the threshold temperature showed a non-significant decrease trend, with a mutation change in 2008. On the watershed scale, the change rate of precipitation in each phase increased with the increase of altitude, and the Snowfall/Rainfall ratio was the opposite, the change of snowfall was mainly affected by temperature and relative humidity, and the change of Snowfall/Rainfall ratio was mainly affected by temperature in Northwest China. This finding can greatly contribute to the scientific understanding of the changing of water resources in Northwest China. It is of great significance to the rational regulation of regional hydrology and water resources.

       

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