EFFECTS OF MOISTURE ON ATMOSPHERIC SHIP WAVES

Effects of moisture on the genesis and evolution of mountain gravity waves and a tmospheric ship waves in the threedimensional multilayer moisture flow over to pography are numerically investigated using the Advanced Regional Prediction Sys tem (ARPS5.0.0.0IHOP5). The results show that the moisttrapped lee wave (the s e cond diverging wave mode) in three dimensional three layer moisture flow over mo untain is apparent in the downstream of the mountain lee side, and it consists o f two diverging wave modes and a transverse wave mode. The genesis and evolution of atmospheric ship waves are extremely sensitive to the initial spatial distri bution of moisture in the atmosphere, and under certain condition, the introduct ion of moisture might reduce the activities of ship waves in the atmosphere. For the threedimensional threelayer flow over a isolated mountain, if th e init ial moisture is distributed on the middle layer, the impact of moisture and diab atic heating on atmospheric ship waves is minor; if the initial moisture is dist ributed on the middle and lower layers, then effects of moisture and diabatic he ating reduce the intensity of atmospheric ship waves; and if the initial moistur e is distributed on the all layers of the model, then the introduction of moistu re into the model atmosphere will reduce the activities of atmospheric ship wave s in the whole atmosphere.