Numerical Simulation Research Of The Atmospheric Boundary Layer Characteristics Over Water-Land Heterogeneous Underlying Surface In Baiyangdian

First of all, some sensitivity tests of the atmospheric boundary layer structure over inhomogeneous underlying surface are carried through by using the mesoscale meteorological model ARPS, the model results not only successfully reproduce the typical characteristics of the sea-breeze circulation, the lake-land breeze circulation, the desert-oasis circulation and the horizontal air crossing the bell-shaped mountain, but also much reveal the physical mechanism of the interaction between surface and wind, temperature and humidity in the atmospheric boundary layer over complex underlying surface. The ARPS model deal with the complex surface properties accurately. The model can simulate the processes and structure of the atmospheric boundary layer over non-uniform surface. After making sure of the model's ability, numerical experiments of the processes and structure of the atmospheric boundary layer over heterogeneous underlying surface in Baiyangdian area are carried out. Model results show the characteristics figures of temperature and humidity, circulation, radiations and turbulence in this area, and also reveal the physical mechanism that affect the special temperature and humidity in this area. The main conclusions: sensitivity experiments show that there are regional circulations and "cold island effect" over non-uniform surface zone for the differences of thermodynamic and dynamic between ocean and land, lake and land, desert and oasis. When the scale of the lake or the oasis is different, the characteristic of its circulation will be different.Because of the block and uplift caused by topography, in the horizontal, air comes to convergence or divergence, and in the vertical, air appears to uplift or sink. In the same time, the effect of block and uplift cause the temperature disturbance in the vertical direction. Model results from the simulation of the Baiyangdian area show that, 14^th Sep, air over the waters is cold source compared with the surrounding air, and atmospheric humidity over the waters is less than that over the land. Regional heat circulation which appears over the adjacent area of water and land, is the main factor that control the distribution of water vapor which near ground, and the turbulent transport results in the higher temperature and humidity over land. The incident shortwave radiation over the water area is slightly larger than that over the land area, maybe because of the larger humidity over the land. The reflected shortwave radiation and the net radiation are much more than that over the land. The incident long wave radiation and the reflected long wave radiation over the land is much than that over the water. During the day, turbulence over the land is much stronger than that over the water, because there is super adiabatic instability layer over the land for its higher temperature. The uplifting and sinking branch of the regional heat circulation are another reason. The Albedo of the water is larger that of the land, because there are so many kinds of aquatic vegetation in the water. Background winds have great influence on the regional temperature, humidity and circulation. Under weak background wind conditions, there is some feedback mechanism between circulation and turbulence. And under strong background winds, circulation can affect the development of the turbulence through weaken the background winds.