| The coastal zones of the world's oceans where land, air and ocean meet are known for both atmospheric and coastal ocean hydrodynamic and thermodynamic patterns which differ from those in other environment because of their weather and climate. The challenge of predicting the motion in the coastal ocean is of interest to coastal oceanographers and meteorologists. They found that the marine atmosphere and the coastal ocean actually exchange buoyance and momentum within the meso-scale spatial and temporal domains of both fluids, spanning two to two thousand kilometers and ten minutes to ten hours on the atmospheric side and one to one thousand kilometers and seconds to two weeks on the ocean side. Therefore, It is very necessary to develop an regional air-sea coupling numerical model in order to face the challenge of reconciling the apparent cause and effect, feedback coupling between the marine atmosphere and coastal ocean, as heat, moisture and momentum are exchanged, over a wide range of spatial and temporal scales of observed motion.The eastern coast of China is not only the west boundary of Western Boundary Currents, but also famous for its numerous embouchures and complex topography. Many researches show that the interaction of marine atmosphere and ocean is obvious and play an important role in the motion of atmosphere and ocean . In this paper, we selected two cases of March in 1995 to discuss the mechanism of two explosively developed cyclone over the Yellow and East China Seas and the effect of air-sea interaction in these development. We also used LASG-REM which is an atmospheric model and ECOM-si which is an ocean model to develop a regional numerical air-sea coupling model of China. The region which we selected is the seas in east of China . The purpose of developing our own coupling model is to investigate the mechanism of the interaction of marine atmosphere and ocean of Chinese coastal zones thoroughly. The main tests and conclusions of this paper are:1. Diagnostic analysis and simulation of cases At first, we improved LASG-REM in topographic resolution, land-use categories and physical parameters, as well as in planetary boundary layer (PBL) parameterizations. In PEL parameterizations, Surface-Energy equation which developed by Blackadar and bulk-aerodynamic parameterization of Deardorff are used. Then, we usedthe improved LASG-REM to diagnose the dynamical processes of the passing extra-tropical cyclone over the Yellow and East China Seas and its explosive development in order to test our improvement. Both the dynamical processes of a passing cyclone evolving into an explosive one over the Yellow and East China Seas and the incipient moisture transfer effects on the sequent development are investigated in dynamical diagnostics and numerical experiment frame. Results suggested that explosive development occurred as significant increase of surface geostrophic vorticity and favorable spatial configure forced jointly by strong temperature advection from baroclinic background in cold season and large latent heat release (enhanced baroclinic energy conversion) by cumulus convective. The large moisture fluxes are on the midway passing over seas and are collected by convergent process of moisture via low level from the South and latent flux from local sea surface. The later is major moisture source during moisture collection process and dominates, to a certain degree, whether the passing cyclone will evolve into an explosive one or not. This will play a significant role on the forecast of marine explosive cyclone.2. Design of numerical air-sea coupled model The coupled model is a two-way coupling model in which the exchanged information coming from atmospheric model (such as wind stress, sensible heat flux, latent heat flux ) and ocean model (such as SST) flowed into each other synchronously. The key technique of our scheme is the inter-process communications in UNIX. We used pipe which complied FIFO(First In and First Out) rule as the communicator to exchange the information of two models a...
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