摘要
为探讨蕴含气球漂移信息的高垂直分辨率L波段分钟探空数据在同化预报中的应用及影响,在初步讨论其基本特征的基础上,采用廓线和逐点两种同化方式,开展单站、降水个例及批量分钟探空同化试验,并与常规探空同化试验对比,得到以下主要结论:分钟数据可补充常规探空无法解析的垂直信息并提供气球漂移精确定位数据;同化分钟探空可有效增加观测在分析中的权重,使分析场更接近实况,逐点较廓线同化的结果差异主要在对流层上层;同化整个预报区域的分钟数据对模式的分析和预报性能有一定影响,漂移造成的风场同化差异在200 hPa及我国北方高空急流位置更明显;整体而言同化分钟数据可一定程度提升模式初始场(高层风场和低层水汽场)品质,主要改善对流层高空风和大量级降水预报性能。
To investigate the application and impact of L-band high vertical resolution minute-level sounding data which include balloon's accurate drifting information at each level on data assimilation and numerical prediction,basic features of these data were preliminarily analyzed in this paper.On this basis,experiment of single station,precipitation case study and batch assimilation tests of the whole simulated domain were conducted using minute-level sounding data via the two assimilating methods of profile and point-bypoint,then compared with the assimilation test using conventional sounding data.It was concluded that;(1) the vertical resolution of L-band minutely sounding data can better match the vertical layers in the model.It can provide additional vertical observation information and precise location data that the conventional sounding data cannot achieve.(2) One-station assimilation test indicates that assimilating minutely sounding data can efficiently increase the weight of observations in the analysis,thus leading to the analysis field more similar to the observations,and differences of analysis field calculated by point-by-point assimilation method and profile way mainly remain in the upper troposphere.(3) The case study and batch tests assimilating the minutely sounding data in the whole forecast region can affect the final analysis and forecast accuracy,and the difference of wind assimilation caused by the balloon's advection drift mainly exists in the positions at 200 hPa,and the upper-level jet stream over northern China.(4) The initial field in the model is overall improved by assimilating L-band minutly sounding data,which mainly positively affect the forecast of winds in the upper troposphere and intense precipitation in larger scales.
出处
《气象》
CSCD
北大核心
2015年第6期695-706,共12页
Meteorological Monthly
基金
国家重点基础研究发展计划(973计划)(2013CB430100)资助
关键词
分钟探空
廓线
漂移
同化预报
minute-level sounding
profile
drift
data assimilation and prediction
