Abstract: Based on the ground-based Agl generator theory,a snowfall enhancement experiment was remotely controlled and catalyzed at the site scientifically selected at Xiling Snow Mountain in order to exploit the orographic cloud water resource in the air.During the typical precipitation processes,the snow crystal spectrum and meteorological data collected before and after the snowfall enhancement experiment were analyzed using the PARSIVEL Laser raindrop spectrometer and the intensive observations from the automatic weather stations.The results show that the surface wind has a great influence on the cloud-formation efficiency from silver iodide nuclei and on the operational target area when the snowfall enhancement is operated.The maximum amount of snowfall increases by 22%.The operational site is determined by the change status of zero velocity lines and by the center distribution of positive and negative velocities in the Doppler weather radar field.The optimal operating time is judged by the vertical airflow distribution of wind profile radar at the boundary layer.The concentration of snow crystal is significantly larger after the operation,and its changing trend is consistent with that of the amount of snowfall.The concentration increasing extent of snow crystal at different diameters is different,among which that with the diameter less than 1.5 mm is the fastest.

Key words: Xiling Snow Mountain, Orographic clouds, Ground-based AgI generators, Laser raindrop spectrometer, Snowfall enhancement