摘要
该文针对北京市气象局业务快速更新循环同化预报系统（BJ—RUC），通过对有无飞机观测资料参加同化的预报试验客观要素预报均方根误差和降水量TS评分的对比分析，探讨了飞机观测资料对短期数值天气预报的影响。结果表明：飞机观测资料的同化对于前9h预报时效内的高空风和温度预报有明显的正面影响。其中，对风预报的正面影响集中在925-250hPa高度上；而对温度预报的正面影响主要体现在850～400hPa之间的各层内。在快速更新循环的暖启动模式下，飞机观测资料同化比冷启动模式下带给预报结果更明显的正面贡献。飞机观测资料参加同化对于降水预报技巧的提高也有正面效应，对24h和12h累积降水量TS评分以及12～18h和18～24h时段内的6h累积降水TS评分有明显提高，提高的最大幅度达50％，并对相应阈值和时段内无飞机观测资料参加同化的试验中雨区偏大现象有改善。分析增量分布特征与同化带来的风温要素3h预报改进的垂直特征基本对应，表明飞机观测资料参加同化对初始场中风场和温度场质量的改进。
AMDAR data has been widely proved valuable in improving accuracy of numerical weather forecast. But assimilation application of AMDAR data in operational NWP model is seldom accessed in China. BJ- RUC, the operational rapid update and cycling NWP system of Beijing Meteorological Bureau, is used to evaluate the impacts of assimilating AMDAR data on forecast performance. Durative experiments with and without AMDAR data are conducted from 15 Jul to 15 Aug, 2007. The average RMSE difference and average precipitation scores difference of AMDAR and NOAMDAR experiments are compared to discuss the impacts of AMDAR on short-range numerical weather forecast. Analysis shows that the assimilation of aircraft data has remarkable positive impacts on the first 9 hours forecast especially on upper levels. Forecasts of wind on the levels of 925 hPa to 250 hPa and temperature on the levels of 850 hPa to 400 hPa are improved. The assimilation of AMDAR data contributes more in rapid updated cycle mode than in cold start mode. It has positive impacts on the threshold score of accumulated precipitation forecast of 0-12 hours, 0-24 hours, 12-18 hours, and 18-24 hours. It also improves the overestimating in the NOAMDAR experiments. The increment analysis shows parallel characteristics with the horizontal distribution of AMDAR data and the vertical improvement characteristic of the 3 hours forecast. The comparability indicates the improvement of wind and temperature in first-guess field made by assimilating AMDAR data. The relative observation errors of AMDAR against Beijing radio- sonde are discussed and proved reliable. It suggests that determining AMDAR observation errors properly in assimilation can help make better use of AMDAR data. Experiments on AMDAR data assimilating application in the operational BJ-RUC system show that AMDAR assimilating has important positive impacts on improving the upper temperature, wind and precipitation forecast. Reasonable amendment of observation errors will bring more efficient utilization of AMDAR data, so priority is assigned to adjusting the AMDAR observation errors in BJ-RUC.
出处
《应用气象学报》
CSCD
北大核心
2010年第1期19-28,共10页
Journal of Applied Meteorological Science
基金
公益性行业(气象)科研专项经费项目"环北京夏季暴雨观测系统研究与可预报行示范试验"(GYHY200706042)
国家自然科学基金项目"非静力数值模式的初始化与高频噪声控制"(40505020)共同资助
