GAME再分析资料与NCEP再分析资料在1998年HUBEX试验期的对比分析
A COMPARISON OF REANALYSIS DATA BETWEEN GAME AND NCEP/NCAP DURING THE PERIOD OF HUBEX
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摘要: 1998年夏季中日合作开展了淮河流域能量与水分循环试验(HUBEX),该试验和GAME其他试验的探空加密观测资料作为原始资料的一部分经过同化分析,得到了GAME再分析资料。该文就是以1998年6~8月我国江淮地区的天气过程为背景,对GAME和NCEP两组不同的再分析资料的基本要素场、导数场、降水量场和地面通量场用气候诊断和统计的方法进行了对比分析。结果表明,在对流层低层和中高层GAME再分析资料的基本要素场及地面的降水场和通量场较NCEP再分析资料更为准确;GAME再分析资料能很好地反映出西南涡东移并影响江淮大暴雨的重要天气特征,而NCEP资料则反映不出这一现象。同时还得到,GAME再分析资料优于NCEP再分析资料的主要原因是GAME的资料同化系统中加入了包括HUBEX等气象科学试验的探空加密观测资料。因此,该文证实了GAME的外场加密观测试验—HUBEX等开展的必要性,说明增加观测资料的时空分辨率对于提高我国天气气候的预报准确率具有重要意义。Abstract:
A comparison of the GAME reanalysis data with the NCEP/NCAR reanalysis data is discussed, where the GAME reanalysis data includes the data observed by HUBEX. On the basis of the weather processes over the Huaihe basin from June to August in 1998, the difference and reliability of the two reanalysis data from the fields of basic element, derivative, precipitation and surface flux were studied by the diagnostic and statistical methods. The results show that the GAME reanalysis data is more reliable than NCEP/NCAP reanalysis data at the bottom and mid-high levels of troposphere, and at the precipitation and surface flux fields the case is just the same. In addition, it revealed that the GAME reanalysis data can show the evolution of the southwest vortex but the NCEP/NCAR reanalysis data cannot do so. Meanwhile, the main cause that the GAME reanalysis data is better than the NCEP/NCAR reanalysis data tends to be the GAME reanalysis data including the sonde intensive observation of the GAME but not to the different assimilation modes of the two reanalysis data. Therefore it also indicates that the HUBEX as the Eastern Asia part of the GAME is necessary to continue, and increasing the temporal and spatial resolution of meteorological elements observed is important to improve our forecasting accuracy of the weather and climate.
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Key words:
- HUBEX;
- Reanaly sis data;
- Comparing analysis
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图 1 1998年夏季GAM E资料与NCEP资料的高度场对比分析
(a)为GAME和NCEP两组再分析资料850 hPa(实线)、700 hPa(长虚线)、500 hPa(空心短虚线)和100 hPa(实心短虚线)高度场相对差值的季节平均(6~8月,每日4个时次)纬向平均(100°~120°E)剖面图,(b)为两组资料的850 hPa高度场分别在00: 00(UTC,下同; 细实线)、06: 00(粗实线)、12: 00(空心短虚线)和18: 00(点虚线)4个时次的相对差值季节平均(6~8月)纬向平均(同(a))剖面图,(c和(d)分别为淮河流域入梅前后6月26日和7月2日的白昼平均OLR场(阴影区,单位: W°m-2 与06: 00 GAME资料(实线)和NCEP资料(虚线)的高度场588 dagpm等值线
表 1 淮河流域水汽收支和降水量(R)相关系数表
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