PNNL

Abstract

Aerosols through cloud condensation nuclei (CCN) affect cloud and precipitation. With increasing concentrations of aerosols, it is important to consider the CCN effect on weather modification results. In this research, seeding with artificial ice crystals is added to the two-moment cloud scheme NSSL of aerosol process in the mesoscale numerical model WRF. Seeding simulations are carried out on a precipitation process in Beijing in the summer of 2008. Sensitivity tests were conducted by modifying the background aerosol concentration and seeding amount to study the seeding effects under different aerosol concentrations. There was a slight difference in the distribution of precipitation among two CCN simulations, with higher CCN, the northern precipitation center is weaker, while the southern center is stronger. There are less qc and more qi when less CCN, and the summary of snow and graupel is not sensitive to CCN. The seeding effect of the same amount of artificial Ni is quite different under different CCN conditions. The higher the CCN concentration, the stronger the rain reduction intensity. When the aerosol concentration increases, the deposition growth of snow is reduced, and the automatic conversion of ice crystals to snow and the collected of ice crystals by snow are reduced, and the melting of snow and graupel to rainwater is also weakened. Aerosols can affect the development of clouds and precipitation, which in turn affects the effects of cloud seeding