Water Vapor,Cloud,and Surface Rainfall Budgets Associated with the Landfall of Typhoon Krosa(2007):A Two-Dimensional Cloud-Resolving Modeling Study

Water vapor,cloud,and surface rainfall budgets associated with the landfall of Typhoon Krosa on 6–8 October 2007 are analyzed based on a two-dimensional cloud-resolving model simulation.The model is integrated with imposed zonally-uniform vertical velocity,zonal wind,horizontal temperature,and vapor advection from NCEP/Global Data Assimilation System(GDAS)data.The simulation data that are validated with observations are examined to study physical causes associated with surface rainfall processes during the landfall.The time-and domain-mean analysis shows that when Krosa approached the eastern coast of China on 6 October,the water vapor convergence over land caused a local atmospheric moistening and a net condensation that further produced surface rainfall and an increase of cloud hydrometeor concentration.Meanwhile,latent heating was balanced by advective cooling and a local atmospheric warming. One day later,the enhancement of net condensation led to an increase of surface rainfall and a local atmospheric drying,while the water vapor convergence weakened as a result of the landfall-induced deprivation of water vapor flux.At the same time,the latent heating is mainly compensated the advective cooling. Further weakening of vapor convergence on 8 October enhanced the local atmospheric drying while the net condensation and associated surface rainfall was maintained.The latent heating is balanced by advective cooling and a local atmospheric cooling.