ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 48 Issue 9 > 2022,48(9):1171-1185. DOI:10.7519/j.issn.1000-0526.2021.080501 Prev Next
Vertical Structure Characteristics of Atmospheric Boundary Layer in Spring Sandstorm over Hexi Corridor
- Article
- Figures
- Metrics
- Preview PDF
- Reference
- Related
- Cited by
- Materials
Abstract:
Sandstorm is one of the most serious disaster weather in the spring of Hexi Corridor. Understanding the atmospheric boundary layer characteristics of sandstorms is an important means to improve the prediction and early warning level and reduce the impact of sandstorm. Using daily high-resolution sounding data at 08:00 BT and 20:00 BT and the ground wind-sand observation data from Dunhuang, Jiuquan, Zhangye and Minqin stations over Hexi Corridor in the spring of 2006-2016, this article investigates the variation characteristics of vertical structure of atmospheric boundary layer in terms of dust intensity at different stations, daily change and duration of duststorm as well as duststorms under different circulation situations from surface up to 5 km height. The results show that the intensity of temperature inversion in the presence of sandstorm at 08:00 BT was above 1.6℃·（100 m）-1, the dry layer thickness of less than 40% relative humidity was more than 3 km, the dry layer thickness of less than 30% relative humidity was more than 1.5 km and the maximum wind speed at 20:00 BT was more than 13 m·s-1. Due to the influence of altitude, topography and underlying soil properties, the lower wind field has obvious diurnal variation and valley wind effect. It was high temperature, dry air, big wind speed and more dust in Dunhuang and Minqin. Zhangye had heigher wind speed affected by the narrow tube effect in the corridor. The lower layer of Dunhuang was mainly southeast to southwest wind, but its upper level and other stations were mainly west to northwest wind. For daily variation of meteorological conditions in the boundary layer at the time of sandstorm, it was dry and warm in morning, but wet, cold and strong wind in the afternoon. The maximum wind speed was 17.6 m·s-1， occurring at height of 0.9 km, south wind occurred near ground from night to morning, west wind occurred in afternoon, dry and light wind occurred over night. When the sandstorm lasted for a long time, the temperature was low in the morning and evening, and the dry layer of the atmosphere with relative humidity ≤ 30% was 2.85 km thick at 08:00 BT in less than 5 hours, while the dry layer being 1.05 km thick lasted for more than 5 hours at 20:00 BT and it was thicker in the morning and night, shallow in the afternoon. The minimum threshold of depression of the dew point was 16-17℃ with maximum height of 2.85-3.00 km. Under different sandstorm circulation conditions, the ridge type was dry and cold in the morning, the maximum wind speed was 14.6 m·s-1 at 0.75 km height， the trough type was wet with cold and strong wind in the afternoon, and the maximum wind speed was 15.7 m·s-1 at 0.9 km height; and the westerly type was dry with cold and light wind blowing near the ground, but wind speed was stronger at the height between 1.2-3.5 km in the morning and higher than 2.4 km in the evening.
Keywords:
Project Supported:
Clc Number:
Mobile website
