Influence of atmospheric ice nucleus concentrations on cold cloud radiant properties and cold cloud reflectivity changes in past years

PAL satellite dataset which have long temporal span is used in the study. Relationship be-tween cold cloud reflectivity and aerosol concentra-tion in Beijing is analyzed as an example. From analysis, cold cloud reflectivity is found to be well correlated with aerosol optical depth. Meanwhile, it is retro-correlated with surface visibility. The results mean that cold cloud reflectivity is possibly influenced by ice nucleus concentration changes. Analysis about cold cloud reflectivity changes during the period 1982-1999 in Beijing shows that reflectivity increases in earlier years and decreases in later years. The data of cold cloud reflectivity in China show that reflectivity in some regions has changed. For the reason that cold cloud is very important in global climate system, those changes of cold cloud reflectivity can lead to climate changes finally.