Observational Studies Of The Stable Boundary Layer In The Summer Night In The Hinterland Of Taklimakan Desert

In this paper,the GPS sounding in July 2017,wind profile radar data and ground meteorological observation data from the Hinterland of Taklimakan Desert were used to analyze the desert summer nocturnal stable boundary layer structure characteristics,weather anomaly potential temperature and wind speed vertical profile characteristic changes;Low-altitude jet in the night was counted and analyzed combining wind profile radar,and the characteristics of jet stream at night was analyzed and researched,The following conclusions were achieved:(1)Statistical analysis was made on the height variation of each layer of the stable boundary layer at night,and the average thickness of the boundary layer at night was 570 m.The average thickness of the residual mixing layer was 2700 m,and the average thickness of the residual inversion layer was 350 m.The stable boundary layer thickness at 7:15am was positively correlated with the surface temperature at that time.(2)Clear potential temperature vertical profile could very good show the characteristics of nocturnal stable boundary layer changes,to be able to clear the display of the residual mixing layer thickness,thickness of nocturnal stable boundary of 500 meters,the residual mixing layer which could keep good convective mixing layer thickness,the thickness of up to 5000 m;The precipitation process was a process of cooling and humidifying,which could destroy the structural characteristics of the stable boundary layer and the residual mixing layer.On rainy days,the maximum thickness of the boundary layer was 650 meters.(3)During the occurrence of sandstorm,the structural characteristics of the night stable boundary layer were destroyed to some extent.There was a layer of temperature that does not increase with height.The thickness of this layer was similar to the vertical thickness of dust storm,and there was a complete residual mixing layer in high air,with clear structure.A new stable boundary layer could be formed in the short time after the night dust storm.The floating dust weather would suppress the structural changes of the convective boundary layer and the stable boundary layer during the day,so that the change of the temperature vertical profile would be smooth and the boundary of each layer will be blurred and indistinct.(4)The development trend of the vertical profile of wind speed in clear weather at night was to increase first and then decrease in the process of increasing.At night,the maximum wind speed of the roof of the boundary layer and the residual temperature of the residual temperature was maximized;At 7:15 a.m,a low-altitude jet stream developed near the top of the stable boundary layer,and the wind speed reached 10.2m/s.In the process of dust storm,the sand dust could be resolved to be about 1000 meters,and the wind speed reached 15m/s,and the near formation was greater than the wind speed in high altitude.After the dust weather,within 1000 meters,there was the development of night low-altitude jet,the maximum wind speed could be as large as 19m/s;In the process of precipitation,the wind speed was greater than before and after the precipitation.After the rainfall,the overall wind speed decreased gradually,and the direction of the wind was shifted to the right,which was consistent with the dust weather.(5)The near stratum of the desert at 7:15 in the early morning of July had the occurrence of low-altitude jet stream in the night,the probability was 50%,the average height of the jet stream was 365 meters,the average wind speed was 11.4m/s,and the main wind direction was east wind.In the process of dust and dust,it was the maximum strength of the low jet stream that can lift the current height and increase the speed of the jet stream.During the day,the jet stream was less than sunny and the jet stream winds more than sunny and less than the dust.The main wind direction of the ground wind was the northeast wind,while the main wind direction of the low-altitude jet was east wind.(6)There was a slight difference in the development characteristics of low-altitude jet streams in desert weather and sandstorm.The low-altitude jet stream in sunny days began to develop at midnight and begins to dissipate in the morning.The sandstorm began to dissipate in the early morning after the sandstorm began.The maximum wind speed of the two jets occurred in the middle of the current development cycle,and the maximum jet height occurred for a period of time before dissipation.