Analysis of Circulation Characteristics and Causes on Two Types of Topographic Precipitation Processes around the Qilian Mountains in Summer
Precipitation around the Qilian Mountains has close relationship with developing of large-scale circulation system and orographic cloud forced by complex topography in this region.The present work compares synoptic pattern and relevant physical parameters as well as development mechanism of two type...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Science Press, PR China
2022-06-01
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| Series: | Gaoyuan qixiang |
| Subjects: | |
| Online Access: | http://www.gyqx.ac.cn/EN/10.7522/j.issn.1000-0534.2021.00102 |
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| Summary: | Precipitation around the Qilian Mountains has close relationship with developing of large-scale circulation system and orographic cloud forced by complex topography in this region.The present work compares synoptic pattern and relevant physical parameters as well as development mechanism of two type precipitation processes around the Qilian Mountains such as CASE1 which occurred during July 19 -20， 2018 and CASE2 which occurred on August 28， 2018 with observed data and high resolution data from WRF model version 3.8.1.Synoptic analyses show that CASE1 precipitation process is the result of interaction between favorable large-scale and local topography， CASE2 is mainly a precipitation process induced by local topography and no significant large-scale circulation system in this process.Results of diagnosis analyses indicate that CASE1 has characteristics such as sufficient water vapor supply， obviously unstable of the stratification， high effective convective energy （1064.84 J·kg-1）， strong vertical shear of the horizontal wind （27.6 m·s-1）， Richardson number （Ri） less than 0 and strong vertical ascending motion et al.before precipitation， which caused the formation of larger area and persistent precipitation process.However， the stratification in CASE2 is more stable than that in CASE1， and the maximum of MCAPE （546.15 J·kg-1） is about half of that in CASE1， the maximum horizontal wind vertical shear （17.37 m·s-1） is far less than that of CASE1， and Richardson number is greater than 0 in the precipitation stage， which means it is a weak convective precipitation process and precipitation rate is relatively smaller as well as and relatively short duration. |
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| ISSN: | 1000-0534 |