不同土壤湿度条件下绿洲边界层特征的敏感性试验

Sensitivity Test of Oasis Boundary Layer Characteristic under Different Soil Moisture

应用NCAR的非静力平衡中尺度数值模式MM5V3.6,设计了三种不同土壤湿度对金塔绿洲边界层的特征影响的敏感性试验。结果表明:土壤灌溉后地表温度和气温升温率较灌溉前有所减小。土壤湿度越大,绿洲温度越低,绿洲的“冷岛效应”越显著。绿洲灌溉后地面感热通量较灌溉前偏低,潜热通量比灌溉前高;土壤湿度越大,这种差异越显著。土壤湿度为0.35时,绿洲能够很好地表现绿洲特性,维持其自身的发展。绿洲边界层高度在灌溉前后有很大的变化。随着土壤湿度的增加,绿洲的边界层高度逐渐降低。这种较低的边界层对绿洲起到了保护作用,它将绿洲的能量与水分保存在较低的边界层中,促进了绿洲的进一步维持和发展。

The characteristics of boundary layer in Jinta oasis were simulated under the different soil moisture using the NCAR non-hydrostatic mesoscale model MM5V3. 6. The results show that the rising rates of both the ground surface temperature and the surface air temperature are less than those of no irrigation. The higher the soil moisture is, the lower the oasis temperature is. The so-called “cold island effect” in oasis is more significant. Once irrigated, the surface sensible heat fluxes decrease, and the latent heat flux is higher. The characters of oasis would be seen when the soil moisture is 0.35. With the increasing of soil moisture, the height of oasis boundary layer will decrease. The oasis＇s energy and moisture will been kept in the lower part boundary layer, it will promote the oasis＇s maintenance and development.