Effects Of Anthropogenic Aerosols On Chinese Ice Clouds Based On Satellite Observations

In this dissertation,the effects of different types of anthropogenic aerosols on ice clouds in China are investigated using multiple sets of satellite data and reanalysis of meteorological data.The study mainly covers the seasonal,interdecadal and spatial variation characteristics of ice cloud characteristics in China;the effects of anthropogenic aerosols on ice clouds;and the differences in the effects of anthropogenic aerosols on ice cloud characteristics under different meteorological conditions.The results show that.Ice cloud fraction,cloud top height,optical thickness,and ice water path all have good seasonal variation characteristics,with high in summer and low in winter.The high value area of ice cloud volume is in the Qinghai-Tibet Plateau region.Ice cloud top height decreases from west to east.The optical thickness of ice clouds is greater in the south than in the north.The effective radius of ice crystals gradually increases from southwest to northeast.As for the influence of anthropogenic aerosols on ice clouds,with the increase of anthropogenic aerosol concentration,the effective radius of ice crystals gradually increases,the pressure at the top of ice clouds first decreases and then increases,and the thickness of ice clouds gradually becomes thicker.Under the condition of anthropogenic aerosol pollution,the effective radius of ice crystals increases by 17% compared with the clean condition,and the increase is the largest in winter(36%);the thickness of ice clouds increases by 32% compared with the clean group,and the increase is the largest in summer and autumn(36%);the pressure at the top of ice clouds increases in heavy pollution,and the increase is the largest in winter(40%).The effective radius of ice crystals is larger in dry atmospheres under different meteorological conditions and is 20% higher than in wet conditions.The variation of ice cloud top pressure under different meteorological conditions is more complex and it is difficult to draw clear conclusions.The thickness of ice clouds is thicker at high water vapor content and low convective intensity when the anthropogenic aerosol pollution is light,and the opposite when the pollution is heavy.The results of the partial correlation analysis show that the relationship between anthropogenic aerosol-ice crystal effective radius and ice cloud thickness is mainly caused by the aerosol effect and is not related to the covariance of meteorological conditions,but the variation of ice cloud cloud top pressure is more influenced by meteorological factors and less influenced by the indirect effect of aerosol.