CAJ | 학술논문

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9 h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925～250 hPa高度上;而对温度预报的正面影响主要体现在850～400 hPa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24 h和12 h累积降水量TS评分以及12～18 h和18～24 h时段内的6 h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3 h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.
해문침대북경시기상국업무쾌속경신순배동화예보계통(BJ-RUC),통과대유무비궤관측자료삼가동화적예보시험객관요소예보균방근오차화강수량TS평분적대비분석,탐토료비궤관측자료대단기수치천기예보적영향.결과표명:비궤관측자료적동화대우전9 h예보시효내적고공풍화온도예보유명현적정면영향.기중,대풍예보적정면영향집중재925～250 hPa고도상;이대온도예보적정면영향주요체현재850～400 hPa지간적각층내.재쾌속경신순배적난계동모식하,비궤관측자료동화비랭계동모식하대급예보결과경명현적정면공헌.비궤관측자료삼가동화대우강수예보기교적제고야유정면효응,대24 h화12 h루적강수량TS평분이급12～18 h화18～24 h시단내적6 h루적강수TS평분유명현제고,제고적최대폭도체50%,병대상응역치화시단내무비궤관측자료삼가동화적시험중우구편대현상유개선.분석증량분포특정여동화대래적풍온요소3 h예보개진적수직특정기본대응,표명비궤관측자료삼가동화대초시장중풍장화온도장질량적개진.
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 radiosonde 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.