摘要
本文利用国家气象中心１９９０年１月１日至１９９２年２月２９日的１～５ｄ、５００ｈＰａ高度场业务预报结果研究了不同球谐函数谱分量和经验正交函数（ＥＯＦ）谱分量的可预报性。对球谐函数谱分量的研究表明可预报性并不是随着空间尺度的增加呈现单调的递减关系，主要表现为在总波数ｎ等于５附近具有最大可预报性。可预报性主要依赖于总波数ｎ，经卷大圆上的波数和纬向圆周上的波数对可预报性具有完全相同的重要意义。对ＥＯＦ谱分量的分析表明，随着ＥＯＦ指数（即序号数）的增大，可预报性依次减小。从ＥＯＦ和球谐函数的关系发现前几个ＥＯＦ分量正是对应着最可预报的球谐函数分量。进一步分析表明，最可预报的分量对应大气运动的慢变流型。这些结果对如何使用数值预报产品以及如何进行延伸预报具有重要意义。
The 1--day through 5--day forecasts of the 500 hPa height field made at the National Meteorological Center of China from the 1st January 1990 to the 29th February 1992 are used to examine the predictability of the spectral coefficients of spherical harmonics and empirical orthogonal functions (EOFs) The analysis of spherical harmonics that the predictability does not increase monotonically with the increase of spatial scales, but the predictability is largest when total wave number n is about 5. The predictability dramatically depends on total wave number n, so zonal wave number and wave number a long the Merifional large circle are equally important. It is found through the examination of the EOFs that the predictability tends to decrease with the increase of the EOF index. The spherical harmonic decomposition of the EOFs shows that the leading EOFs consist of the spherical harmonics which are more predictable. It is also confirmed that the most predictable components are characterized by slow evolution. These results are importat to the application of forecast products and to extended--range forecasting.
出处
《大气科学》
CSCD
北大核心
1996年第3期290-297,共8页
Chinese Journal of Atmospheric Sciences
基金
KY-85-10项目
大气科学和地球流体力学数值模拟国家重点实验室资助
关键词
实际预报
可预报性
天气预报
时空依赖性
operational forecast predictability spectral coefficient of spherical harmonics spectral coefficient of the EOFs slowly evolving component
