2000—2019年西北地区云水资源时空特征研究

Spatiotemporal characteristics of cloud water resources in Northwest China from 2000 to 2019

  • 摘要: 为认识西北地区的云水资源(Cloud Water Resource,简称CWR)特征以及科学规划人工增雨开发空中水资源作业布局,利用2000—2019年中国1°×1° CWR观测诊断评估数据集,采用线性拟合和经验正交函数分解(EOF)等方法,统计分析了西北地区CWR的分布及演变气候特征。结果表明:(1)从全区整体看,CWR的相关物理量(状态量、平流量、总量和降水效率)主要表现为夏季最高,春、秋季次之,冬季最低的季节变化特征。其中,春季CWR总量约为1736亿t(折合柱水量约为51.2 mm),仅次于夏季;春季水凝物降水效率为48.7%,相较于秋季,春季的CWR开发潜力更大。(2)从区域内1°×1°网格的计算结果得到空间分布,受地势与环流的影响,近20年CWR年总量及水汽年总量、水凝物年总量的多年平均空间分布呈“两高一低”的特征,高值位于西风急流区与季风影响边缘区,低值区主要位于高原气候区。(3)近20年,西北地区格点的CWR年总量平均以23.6 mm/a速率增加,其中春季的增加趋势最显著,增速为8.5 mm/a。季节分布上,CWR夏季最多,春、秋季次之,冬季最少;水凝物降水效率夏季高,秋、春季较低,冬季最低。(4)CWR年总量的EOF分解第一模态(EOF1)贡献率为78.2%,分布特征为区域东部较高,在2008年出现年际转折,开始转变为CWR东部多、西部少的分布格局。(5)在西北地区典型区域中,天山区域年平均及格点平均后的CWR年总量以及水凝物降水效率均高于祁连山区,年际变化上祁连山区的CWR在增多,天山区的在减少。

     

    Abstract: In order to understand the characteristics of Cloud Water Resource (CWR) in Northwest China and scientifically plan the layout of air water resource for artificial precipitation stimulation development, the 1°×1° CWR observation diagnostic evaluation dataset in China from 2000 to 2019 is used to statistically analyze the distribution and evolution of CWR in Northwest China. The linear fitting and empirical orthogonal decomposition methods are employed. The results show that: (1) Over the entire area, physical quantities related to CWR (including state quantity, plain discharge, total amount and precipitation efficiency) are mainly the highest in summer, followed that that in spring and autumn, and the lowest in winter. Among them, the total CWR in spring is about 173.6 billion t (equivalent to about 51.2 mm column water), which is close to that in summer. The precipitation efficiency of hydrometeors in spring is 48.7%, and the development potential of CWR is greater than that in autumn. (2) Calculation results in the 1°×1° grids of the region indicate that spatial distributions of annual total CWR, annual total water vapor and annual total hydrometeors in the past 20 years are characterized by a "two highs and one low" pattern due to the influences of terrain and circulations. The high values are located in the marginal regions affected by the westerly jet and monsoon, while the low values are mainly distributed in the plateau climate region. (3) In the past 20 years, the annual total CWR at the 1°×1° grids in the Northwest China has been increasing at an average rate of 23.6 mm/a, and the increase trend is the most significant in spring with a growth rate of 8.5 mm/a. In terms of seasonal distribution, the CWR is the highest in summer, followed by that in spring and autumn, and the least in winter. The precipitation efficiency of hydrometeors is high in summer, low in spring and autumn, and lowest in winter. (4) The contribution rate of the first EOF decomposition mode (EOF1) of CWR is about 78.2%. The distribution feature is that the eastern part of the region is relatively high. An interannual turning point occurred in 2008, when the distribution pattern of more CWR in the east and less in the west began to change. (5) In typical areas of Northwest China, the annual total CWR and precipitation efficiency of the annual average pass point in the Tianshan mountains are higher than those in the Qilian mountains, and the CWR in the Qilian mountains is increasing, while the Tianshan mountains are decreasing.

     

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