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东亚地区大气辐射能收支(三)--云天大气的地气系统热量收支 总被引:5,自引:2,他引:5
本文是东亚地区大气辐射能收支”的第三部分,讨论了如下几个问题: 1.云天大气长波辐射和辐射差额分布。结果指出,除7月份西藏高原地区外,云天和晴天长波辐射分布特征基本相同,而其辐射差额分布又和相应月份的大气长波辐射分布特征基本一致。 2.东亚地区对流层大气热源热汇分布:8月份整个东亚地区都是冷源,在新疆地区和中国东部北纬32°—25°之间有两个冷中心。在7月份整个东亚地区都是热源,在西藏高原东南部有一个最强的热源中心。新疆北部有一个小的热源中心。 3.东亚各地区的地气系统各种热量收支。首先就整个东亚地区地气系统而言,7月份得到热量基本上补偿了1月份损失的热量,但就大气而言,1月份热量损失大于7月份热量的获得。其次各地区各种热量收支特征并不一致。 相似文献
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DESIGN AND TEST OF AN IMPROVED SCHEME FOR GLOBAL SPECTRAL MODEL WITH REDUCED TRUNCATION ERROR 总被引:3,自引:0,他引:3
An improved scheme of spectral model has been investigated in this paper. Through the introduction of a reference atmosphere, prognostic variables become smoother on the tilted sigma-surface over mountains or a frontal zone, and thus truncation errors are reduced. As a result, the problems about Gibbs waves and negative value of model topography on the sea, which are encountered in the current spectral model in the world, can be solved by the improved scheme. For comparison we have performed the numerical integrations of barotropic and baroclinic Rossby-Haurwitz waves, as well as the prediction of real cases with the improved scheme and the current scheme of spectral model. These results show that the scheme presented in the paper is better than the current scheme of spectral model. 相似文献
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数值预报模式动力框架发展的若干问题综述 总被引:14,自引:3,他引:11
作者就大气数值模式动力框架发展的几个问题做了回顾和展望.关于模式地形的处理,讨论了"地形追随"(terrain-following)坐标和"台阶地形"(step-mountain)η坐标的优点、问题和对策.关于物理量守恒格式的构造,回顾了从"瞬时"守恒到隐式、显示和半隐式完全(包括时间离散)守恒格式的发展和近况,介绍了加速非线性全隐式问题迭代收敛的途径.还讨论了半拉格朗日守恒格式的构造问题.最后,对目前广泛使用的全球谱模式,讨论了其长处、局限和发展前景,并简单介绍了谱元方法. 相似文献
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完全非内插半拉格朗日格式在一维
Burgers方程及二维浅水波方程上的应用 总被引:3,自引:2,他引:1
在作者过去提出的完全非内插半拉格朗日格式的基础上,针对半拉格朗日格式由于内插带来预报场人为的光滑性问题,进一步发展了这种计算格式,证明了此格式的计算稳定性。为检验这种新的计算格式的性能,在一维和二维问题上进行了应用。在一维问题中采用了一维无粘Burgers方程(方程中有突变点);二维问题采用了浅水波方程,同时将这些计算结果与Ritchie方案及欧拉方案或一般半拉格朗日内插方案的计算结果进行了比较,发现新格式消除了内插和预报场的人为光滑,并且计算精度有一定程度的提高,这为以后将此格式推广到全球谱模式打下了基础。 相似文献
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In this paper, the authors develop the earlier work of Chen Jiabin et al. (1986). In order to reduce spectral truncation errors, the reference atmosphere has been introduced in ECMWF model, and the spectrally-represented variables, temperature, geopotential height and orography, are replaced by their deviations from the reference atmosphere. Two modified semi- implicit schemes have been proposed to alleviate the computational instability due to the introduction of reference atmosphere. Concerning the deviation of surface geopotential height from reference atmosphere, an exact computational formulation has been used instead of the approximate one in the earlier work. To re duce aliasing errors in the computations of the deviation of the surface geopotential height, a spectral fit has been used slightly to modify the original Gaussian grid-point values of orography.A series of experiments has been performed in order to assess the impact of the reference atmosphere on ECMWF medium- range forecasts at the r 相似文献
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半拉格朗日平方守恒计算格式的研究 总被引:6,自引:5,他引:6
作者研究了一种新的显式平方守恒的半拉格朗日计算格式.该格式是欧拉空间平方守恒格式在半拉格朗日空间的推广和发展,并采用了守恒插值方法.此外,还给出这种格式在一维原始方程上的应用. 相似文献
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