C波段雷达反射率因子在CMA-GD模式中的应用

使用CMA-GD模式及云分析系统，引入云南C波段多普勒雷达反射率因子资料，对2019年7月9日过程进行模拟试验，分析引入反射率资料对模式初始场和降水过程预报的影响。（1）引入反射率后，云中和底部的云量有所增加。水汽在900~200 hPa有大范围增加，能有效地调整降水区域的水汽分布。对模式顶层温度的调整较大，而对风场的影响较小。（2）引入反射率后，对3 h内降水强度及落区有较大改善，4~6 h的预报有所改善，7 h以后改善不明显。（3）引入反射率资料后，1~4 h大气可降水量增量较明显，5~9 h增量较前4 h明显减小。（4）在河口上空云水和水汽在950~400 hPa增加，霰、云冰和云雪在600~400 hPa增加，雨滴在1 000~500 hPa增加。水凝物增加，有利于河口站降水的发生。 

APPLICATION OF C-BAND RADAR REFLECTIVITY IN CMA-GD MODEL

Based on the CMA-GD model and Cloud Analysis System, the present study introduced the C-band Doppler radar reflectivity data to simulate the precipitation event occurred on July 9, 2019 in Yunnan, and analyzed the impact of the introduction of radar reflectivity data on the improvement of the initial field of the model and the forecast of this heavy precipitation process. The results showed that: (1) The introduction of radar reflectivity increased the number of clouds within and at the bottom of the cloud. Water vapor had a wide range of increase at the 900~200 hPa layer, and this could lead to effective adjustment of water vapor distribution in the precipitation zone. Moreover, it caused a large adjustment to the temperature of the model top but a small change to the wind field. (2) The introduction of radar reflectivity significantly improved the forecast of precipitation intensity and precipitation zone over a 3 h period. There was an improvement in the 4~6 h forecast, with no significant improvement in forecasts for longer period of time. (3) According to the model forecast of hourly atmospheric precipitable water, the introduction of reflectivity data brought more obvious increment of atmospheric precipitable water in the first 1~4 h, and significantly decreased increment in 5~9 h compared with the first 4 h. (4) At Hekou, the cloud water and water vapor increase at the 950~400 hPa layer, graupel, cloud ice and cloud snow increase at the 600~400 hPa layer and raindrop increase at the 1000~500 hPa layer increased after the introduction of reflectivity. The increase of water condensate is conducive to the occurrence of precipitation at Hekou station.