Equatorial Atmospheric Waves and Their Association to Convection
Equatorial Atmospheric Waves and Their Association to Convection
复制标题
赤道大气波及其与对流的关联
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
J. Lafore
中科院分区：
文献类型：
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作者：
P. Pires;J. Redelsperger;J. Lafore
在海洋-大气耦合响应试验（COARE）密集观测期间，分析了西太平洋和中太平洋地区赤道波系统及其与对流活动的关系。该研究使用地球静止气象卫星红外温度观测和正在运行的欧洲中期天气预报中心分析，并辅以COARE观测。对数据进行了光谱分析和复主成分分析。以赤道俘获波的线性理论为指导，检测了三种波的存在。在7 ~ 10天的周期范围内，在日期变更线以东的弱对流活动区域发现了51个罗斯比波。在发生强烈对流的西赤道太平洋上空，7 - 10天波不具有线性罗斯比波的一般特征，但它们与西风爆发和对流的活跃期密切相关。经向风分析显示强烈的罗斯比-重力混合波，平均周期为5天，相速度为西向，群速度为东向。在西太平洋上空，发现对流与发散场的反对称结构密切相关，正如线性理论所预测的那样。在200 hpa辐散场中，可观测到51个周期小于2.5天的重力波。它们向西和向东快速传播（约25米/平方米），并与对流星团有很强的相关性。
Equatorial wave systems and their relationships with convective activity are analyzed in the western and central Pacific regions during the Coupled Ocean‐Atmosphere Response Experiment (COARE) intensive observation periods. The study uses Geostationary Meteorological Satellite infrared temperature observations and the operational European Centre for Medium-Range Weather Forecasts analyses supplemented with COARE observations. Spectral and complex principal component analysis are applied to the data. Using the linear theory of equatorially trapped waves as a guideline, the existence of three types of waves is detected. In the 7‐10-day period range, n 5 1 Rossby waves are found to the east of the date line, in a region of weak convective activity. Over the western equatorial Pacific, where intense convection occurs, the 7‐10-day waves do not possess the general characteristics of linear Rossby waves, but they are strongly linked to the active phases of westerly wind bursts and of convection. Analysis of the meridional wind reveals intense mixed Rossby‐gravity waves with a mean 5-day period and westward phase and eastward group velocities. Over the western Pacific, the convection is found to be strongly correlated with the antisymmetric structure of the divergent field, as predicted by the linear theory. In the 200-hPa divergence field,n 5 1 gravity waves are visible, having periods shorter than 2.5 days. They rapidly propagate (about 25 m s21) both westward and eastward, and have strong correlations with convective clusters.