干旱区研究2024，Vol.41Issue(8)：1272-1287,16.DOI:10.13866/j.azr.2024.08.02
不同风场结构下贺兰山地形降水的理想数值试验
Ideal numerical tests of topographic precipitation around the Helan Mountain under different wind field structures
摘要
Abstract
Topographic precipitation is one of the main types of precipitation in northwest China.It is therefore of great significance to achieve a deeper understanding of the mechanism of topographic precipitation formation to improve forecasting ability.In this study,the vertical distribution structure of different types of wind fields was constructed based on the high-altitude environmental parameters during 20 heavy rains around the eastern foot-hills of Helan Mountain,and the em_hill2d_x module of WRF model was used to conduct ideal numerical experi-ments on the influence of different types of wind field on precipitation distribution.The results show that:(1)The dry air flow of two different types of wind fields(with/without wind shear)on the windward slope of the moun-tain range has an uplift effect of terrain on the windward slope air flow.The leeward slope fluctuation showed dif-ferent characteristics;under the condition of single layer uniform flow,the leeward slope is mainly represented by a mountain wave propagating in the vertical direction.Under the wind field with low-level wind shear,the lee-ward side mainly reflects the characteristics of the dorsal wave,and the gravity wave has the characteristics of co-existing horizontal and vertical propagation.With the increase in low-level wind shear,the characteristics of the horizontal propagation of the dorsal wave become increasingly obvious.(2)The simulated precipitation under the condition of a single layer of uniform wet airflow is mainly located on the windward side,and the precipitation in-tensity is relatively weak on the leeward side under the influence of strong downhill wind.When the wind speed increases to more than 10 m·s-1,the large cloud water content area on the windward side converges to the top of the mountain,and the precipitation intensity increases significantly.In the presence of low-level wind shear flow moving over the mountains,the test result shows that both the windward and leeward side there is a strong rain-fall center,with a deep convective system on the leeward slope,and the precipitation on both sides increases with the increase in wind speed.(3)The simulation results under the condition of low-altitude east wind and high-alti-tude west wind show that the appearance of high-altitude west wind strengthens the updraft on the windward slope and is not conducive to the transport of water vapor downstream;the precipitation on the leeward side is sig-nificantly weakened;the precipitation is more concentrated near the upper reaches of the mountain peak;and the intensity also increases to a certain extent.This is one of the main reasons for the significant difference in precipi-tation characteristics between the two sides of the Helan Mountain.关键词
地形降水/理想试验/重力波/对流系统/贺兰山Key words
topographic precipitation/ideal test/gravity wave/convection system/Helan Mountain引用本文复制引用
李超,隆霄,曹怡清,韩子霏,王号,郑景元..不同风场结构下贺兰山地形降水的理想数值试验[J].干旱区研究,2024,41(8):1272-1287,16.基金项目
国家自然科学基金(42175088,41965001) （42175088,41965001）
宁夏回族自治区科技创新领军人才培养工程(2021GKLRLX05) （2021GKLRLX05）
