Seasonal migration of cirrus clouds over the Asian Monsoon regions and the Tibetan Plateau measured from MODIS/Terra

By using a 4-year data set of the Moderate Resolution Imaging Spectroradiometer (MODIS) cirrus cloud reflectance, the seasonal migration of cirrus clouds over the Asian Monsoon regions and the Tibetan Plateau has been studied. There are two distinct regions with large amount of high clouds. One is located between the equator and 20degreesN, where intensified high clouds show clear northward and southward movements in association with the monsoon. The other is over the Tibetan Plateau, where large amount of cirrus clouds occurs in March to April and shows a more standing feature. Moreover, the significant amount of high clouds over two regions appears to be independent of each other. The one over the Tibetan Plateau is believed to be generated by relatively warm and moist air being slowly lifted over a large area by an approaching cold front and topographic lifting, and the other by the outflow or remains of cirroform anvils of cumulonimbi associated with deep convection in the Intertropical Convergence Zone (ITCZ) and monsoon systems.