Eastward propagating ∼2‐ to 15‐day equatorial convection and its relation to the tropical intraseasonal oscillation
Eastward propagating ∼2‐ to 15‐day equatorial convection and its relation to the tropical intraseasonal oscillation
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东传〜2～15天的赤道对流及其与热带季节内振荡的关系
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
F. X. Crum
中科院分区：
文献类型：
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作者：
T. Dunkerton;F. X. Crum
本文分析了1980-1989年赤道附近窄纬带的长波辐射异常，以阐明热带季节内振荡（TIOs）和天气尺度对流活动的传播和相互作用。从两个频段（分别对应于30-60天和22 -15天的周期）重建的OLR数据的Hovmoller图显示了东移TIO（3-7 m s−1）和东移天气尺度对流（10-13 m s−1）的相速度之间的明显区别。从印度洋到西太平洋的TIO的相干传播经常被观察到，在海洋大陆上的振幅暂时减小。高频异常的传播一般局限于单个盆地。赤道区天气尺度对流向东传播的优势与赤道外辐合带向西传播的优势形成鲜明对比。TIO与每日OLR所解决的高频活动之间的相互作用可以看出，在TIO的对流活跃阶段，向东天气尺度事件（以及一般高频活动）适度增强。
Anomalies of outgoing longwave radiation (OLR) in 1980–1989 were examined in a narrow latitude band about the equator to elucidate the propagation and interaction of tropical intraseasonal oscillations (TIOs) and synoptic-scale convective activity. Hovmoller diagrams of OLR data reconstructed from two frequency bands (corresponding to periods of ∼30–60 days and ∼2–15 days, respectively) revealed a clear distinction between the phase speed of eastward moving TIOs (3–7 m s−1) and that of eastward synoptic-scale convection (10–13 m s−1). Coherent propagation of TIOs from the Indian to the western Pacific Oceans was often observed with temporary diminution of amplitude over the maritime continent. Propagation of high-frequency anomalies was generally confined to an individual basin. Dominance of eastward propagating synoptic-scale convection in the equatorial zone contrasts sharply with the westward propagation of off-equatorial convergence zones. Interaction between the TIO and high-frequency activity resolved by daily OLR was visible as a modest enhancement of eastward synoptic-scale events (and of high-frequency activity in general) during the convectively active phase of the TIO.