泄洪雾化对天气环境影响的松弛同化方法研究

为实现在综合考虑地形和环境背景场条件下,模拟泄洪期间局地区域天气环境的变化情况,以数值天气预报系统为基础,建立了泄洪雾化对天气环境影响的松弛同化方法。结合大岗山水电站一次降雨过程和实际观测资料,拟定了泄洪雾化同化数据分类设置的参考值范围。运用泄洪雾化对天气环境影响的松弛同化方法,对大岗山水电站泄洪期间的天气环境变量进行了同化计算。由于大岗山水电站仅有2015年9月14日15∶30—16∶40泄洪数据,选取2015年9月14日16∶00时刻模拟数据分析得到,在考虑风向变化的条件下,风速变化值为8.76 m/s,纵向影响范围约2.1 km;温度降低了3.32℃,纵向影响范围约2 km;相对湿度升高了8.71%,纵向影响范围约2.8 km。模拟结果表明,风速受水舌风影响风向改变、风速升高,温度受泄洪雾化降雨影响降低,相对湿度受雨雾蒸发影响升高。同化模拟的结果均向观测数据趋近,模拟结果符合实际的观测情况。

Study on nudging assimilation method for the impact of flood discharge atomization on weather environment

Under the condition of comprehensive consideration of terrain and environmental background field, the variation of local weather environment during flood discharge is simulated. Based on the numerical weather prediction system,the nudging assimilation method of flood discharge atomization on weather environment is established. Combined with the primary rainfall process and actual observation data of the Dagangshan Hydropower Station, the reference range of the flooding atomization assimilation data classification setting is proposed. Using the nudging assimilation method of flood discharge atomization on the weather environment, the weather environment variables during the flood discharge of Dagangshan Hydropower Station were assimilated. Since the Dagangshan Hydropower Station only has 15:30-16:40 flood discharge data on September 14, 2015, it is selected from the simulation data at 16:00 on September 14, 2015. At 16:00 on September 14, 2015, under the condition of changing wind direction, the wind speed change value is 8.76m/s, the longitudinal influence range is about 2.1km, the temperature is reduced by 3.32° C, and the longitudinal influence range is about 2km; relative humidity increased by 8.71%, the longitudinal influence range is about 2.8km. The simulation results show that the wind speed is affected by the water tongue wind, the wind speed is increased, the temperature is reduced by the flooding atomization rainfall, and the relative humidity is affected by the rain fog evaporation. The results of the assimilation simulation approach the observed data,and the simulation results are in line with the actual observations.