The impact of horizontal resolution on moist processes in the ECMWF model
The impact of horizontal resolution on moist processes in the ECMWF model
复制标题
ECMWF模型中水平分辨率对潮湿过程的影响
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
S. Grotch
中科院分区：
文献类型：
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作者：
T. Phillips;L. Corsetti;S. Grotch
利用ECMWF（cycle 33）模式在T21、T42、T63和T106谱尺度上模拟的夏季和冬季气候资料，分析了水平分辨率变化对大气水汽、云、对流和降水的影响。许多潮湿过程的质的变化发生在从T21到T42的过渡中，特别是在热带地区;在更高的分辨率下，主要是从T42建立的模式的增量变化。大规模的热带潮湿过程模拟更现实的T21比在更精细的分辨率，可能反映了更精细的尺度动力学和物理参数化的基本假设适用的尺度之间的不匹配。全球降水量随着分辨率的增加而单调增加，这是对流增加的结果。然而，由于热带地区的干燥，全球云量在从T21到T42的过渡中减少，但随后在更精细的分辨率下略有增加。这些小的全球增加是不同区域的补偿变化的结果：由于低纬度大气干燥导致的云量减少被高纬度增加所抵消，高纬度增加是由于与更精细分辨率的大气冷偏差增强相关的相对湿度增加。
Summer and winter climates simulated with the ECMWF (cycle 33) model at spectral scales T21, T42, T63 and T106 are analyzed to determine the impact of changes in horizontal resolution on atmospheric water vapor, clouds, convection, and precipitation. Qualitative changes in many moist processes occur in the transition from T21 to T42, especially in the tropics; at higher resolutions mostly incremental variations from patterns established at T42 result. Large-scale tropical moist processes are simulated more realistically at T21 than at finer resolutions, possibly reflecting a mismatch between the finer-scale dynamics and the scales at which the underlying assumptions of the physical parameterizations apply. Global precipitation increases monotonically with resolution, as a consequence of increasing convection. Global cloud cover, however, decreases in the transition from T21 to T42 due to drying of the tropics, but then increases slightly at finer resolutions. These small global increases are an outcome of compensating changes in different regions: decreases in cloud cover due to drying of the atmosphere at low latitudes are offset by high-latitude increases resulting from enhanced relative humidity associated with an intensifying atmospheric cold bias at finer resolutions.