Study on Effects of Vegetation on Atmospheric Circulation

为了建立一个模拟模式来估计植被对大气环流的作用，在一个格罗夫内和格罗夫外进行了小气候观测。所得结果如下。1.白天，格罗夫内的温度比格罗夫外的温度低。下午3 - 4点后，格罗夫内的温度比格罗夫外的温度高，这种状态一直持续到第二天早上的日出。格罗夫内外温度变化的相位差约为30分钟。在雷雨等大风天气下，格罗夫林内温度随林外温度的变化而变化。2.利用廓线关系估算了涡旋扩散系数，并计算了树冠附近热量通量和水分通量的日变化。结果似乎是足够的。3.格罗夫林内白天净辐射约为30- 40 w/m^2。4.地表下5cm土壤温度变化1 ℃，而格罗夫外相同位置土壤温度变化4-5 ℃。5.利用三维大涡模拟方法建立了大气流动模拟模型。今后，必须考虑热平衡方程。

In order to develop a simulation model to estimate the role of vegetations on atmospheric circulation, observations of micro-climate were carried out in a grove and outside the grove. The results obtained are as follows. 1.Temperature in a grove is lower compared to outside the grove in the day time. After3-4pm.temperature in a grove becomes higher compared to outside the grove and this state continues to sunrise of next morning. The phase difference of temperature variation between inside and outside the grove is about 30 minutes. In the case of strong wind such as thunderstorm, the temperature of inside the grove changes immediately with temperature of outside. 2.The eddy diffusivity was estimated using Profile relations and daily changes of heat and moisture flux near the crown were calculated. The results seemed to be adequate. 3.The net radiation during day time was around 30-40w/m^2 inside the grove. 4.Soil temperature of 5cm under the ground surface changed 1ﾟC,meanwhile, soil temperature of same position outside the grove changed 4-5ﾟC.5.The simulation model of air flow is under construction using 3-dimensional LES model. In future, the heat-balance equations must be taken into account.