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Aerosols influence cloud microphysical properties by acting as cloud condensation nuclei and ice nuclei. Aerosols have the potential to modify the location and intensity of precipitation by changing cloud properties. However, identifying precipitation changes induced by aerosols remains a significant challenge for current research. Dust aerosol carried by dust storms is an important source of ice nuclei. China and Mongolia are the primary desert regions in Asia and the world. The Mongolian cyclone in northern China is one of the significant weather systems that cause sandstorms in both countries. Studying the impact of dust aerosols on clouds under the weather conditions of Mongolian cyclones and sandstorms is of great significance. Due to challenges of aerial observations during dust storms, the impact of dust aerosols on clouds is minimally understood during Mongolian cyclone dust storms. In order to investigate the impact of dust aerosols on clouds, a study is conducted based on the comprehensive observation experiment of clouds in Beijing Area carried out by Beijing Weather Modification Center. An extremely rare case of strong sandstorm weather caused by a Mongolian cyclone and cold front is observed on 24 April 2009. The vertical macro and micro physical structure characteristics of dust cloud and clean cloud are compared and analyzed, and the potential influence of dust aerosols on clouds is discussed. Results show that dust aerosol transferred from China-Mongolia areas is an important source of ice nuclei in North China. It can be transferred vertically to a height of 3200 meters above the cloud top. The concentration of ice nuclei in the dust background area is significantly increased by 10 times compared to that in the clean background area. This increase further affects the microphysical structure of cumulus and stratocumulus clouds with high cloud top temperatures (-6 ℃ to -3 ℃) by altering the process of ice crystal formation. At the same temperature, the average concentration of ice crystals in the dust cloud increases significantly by nearly 10 times compared to that in the clean cloud. The liquid water content is reduced, leading to the formation of a large number of small ice crystal particles in the cloud. It inhibits the rime process and results in a significant reduction in the average concentration of precipitation particles compared to that in the clean cloud. Additionally, the spectral width of cloud droplets, ice and snow crystals, and precipitation particles is significantly narrower than that in the clean cloud. It will eventually weaken the precipitation, which will have a significant impact on the weather and climate in North China. It is helpful to enhance our understanding of the indirect effects of aerosols.

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According to field observations, the atmospheric boundary layer is usually unstably stratified before a dust and sandstorm, the particle-laden turbulent gravity current with an extremely high Reynolds number. In this paper, an inviscid model was built to study the mechanism governing the slumping phase of gravity current. It is shown that the dimensionless current front speed, the Froude number, decreases when the current fluid or the ambient medium or both fluids are unstably stratified. In spite of the density interface mixing, the relation between the front speed and the front height described by the inviscid model agrees with the numerical simulation results, where the lock-exchange gravity currents with different initial lock heights were calculated for different unstable stratification cases. Furthermore, the velocity increments obtained by field observations at the sandstorm fronts are satisfactorily consistent with the evaluations of the model, suggesting that the inviscid mechanism makes contribution to such high Reynolds number turbulent flows.

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Jianzhu Cailiao Xuebao: Journal of Building Materials is the property of Journal of Building Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Jianzhu Cailiao Xuebao: Journal of Building Materials is the property of Journal of Building Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the sandstorm data collected from the four meteorological stations in western Shache, Markit, Bachu and Kashgar of Southern Xinjiang in recent 10 years, the time and speed characteristics of the sandstorms were studied. The results show that dust storm frequency has tapered year by year in recent 10 years. Kashgar's dust storms tapered more in the first three years. In the last two years, frequencies still decreased in Kashgar, but it increased in Shache and Markit. The sandstorms mainly occurred from April to June, especially in April. The dust storms mainly occurred at 20:00 in the evening, with a maximum duration of about 10 h happening in shache, Markit and Bachu. The average wind speed of sandstorms of the 4 places was different from each other. As there is a higher climate testing level in recent years, data acquisition for 1 times changes from 10 minutes to 1 minute. The sandstorm characteristics of wind speed were more accurately studied. Wind speed characteristics of the longest duration time of the two sandstorms were analyzed in Bachu and Markit. The wind direction is respectively northwest in Markit and northeast in Bachu. The wind speed changed obviously in Markit, with an average reriodic variation of 4 minutes, and is of obvious of gust characteristics. [ABSTRACT FROM AUTHOR]