青藏高原一次强对流过程对水汽垂直输送的数值模拟

本文采用中尺度天气研究预测模式(WRF)模拟了青藏高原那曲地区的一次强对流过程,分析了强对流对水汽的垂直输送量及对模式不同云微物理参数化方案的敏感性.通过与实测资料的比较,发现此次模拟在对流发生时间、地点、降水时间等方面均与实际接近.敏感性试验表明:当对流发生时,对流区域向上的水汽通量随海拔高度呈先增大后减小的趋势,该...

A Numerical Study of the Vertical Transport of Water Vapor by Intense Convection over the Tibetan Plateau

The vertical transport of water vapor by a severe convective process occurring in Nagqu area over the Tibetan Plateau has been investigated using the Weather Research Forecast (WRF) model with different cloud microphysical schemes. The simulated characteristics of the storm reveal good agreement with observations, such as the onset and location of convection and precipitation. The results show that when the convective cloud arises, the upward flux of water vapor over the convective region increases at first then declines with altitude, and is not sensitive to cloud microphysical schemes. Similar trend is also found for the total water vapor integrated over a period of 24 hours. A further analysis shows that this trend is correlated to the vertical updraft in the cloud, that is, both the short-time humidifying effect in the upper troposphere and duration are sensitive to cloud microphysical parameterization schemes. The largest difference of the maximum upper tropospheric water vapor mixing ratio can reach 20.3% among different schemes, leading to humidifying lasting from 1.5 to 7 hours. Taking a 24-hour average can reduce the sensitivity of upper troposphere humidity, but the maximum still reaches 14.3%. The results of this study indicate that when the WRF model is used for studies of the effects of deep convection on the upper tropospheric water vapor, the uncertainty induced by using different microphysical schemes cannot be neglected within 24-hour time scale.