Cloud Observation by Aircraft During Dust Storms

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 minimal 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 transfers from ChinaMongolia areas is an important source of ice nuclei in North China. It can be transfered 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 par