Interannual variability of diurnal tide in the tropical mesopause region: A signature of the El Nino‐Southern Oscillation (ENSO)
Interannual variability of diurnal tide in the tropical mesopause region: A signature of the El Nino‐Southern Oscillation (ENSO)
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DOI：
10.1029/2005gl022928
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发表时间：
2005-07
影响因子：
5.2
通讯作者：
S. Gurubaran;R. Rajaram;Takuji Nakamura;T. Tsuda
中科院分区：
文献类型：
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作者：
S. Gurubaran;R. Rajaram;Takuji Nakamura;T. Tsuda
本文分析了1993-1999年在雅加达（6.4°S, 106.7°E）和Tirunelveli（8.7°N, 77.8°E）上空86 km的长期MLT雷达观测资料。每月对这些地点经向潮汐振幅的估计显示出明显的年际变化。本研究使用卫星导出的出射长波辐射（OLR）作为热带深部对流的代表。去除复合季节周期可以得到雅加达和蒂鲁内尔韦里日潮的“异常”，这与西太平洋地区（~ 120°E）的OLR异常相关。本文认为，响应厄尔尼诺-南方涛动（ENSO）而起源于西太平洋地区的低层大气大尺度对流系统，通过潜热释放或水汽的大尺度再分布促进了非迁移潮的激发，这些潜热释放或水汽再分布与主导迁移潮竞争，并可能导致观测到的日潮年际变化。
Long‐term MLT radar observations of the diurnal tide at 86 km over Jakarta (6.4°S, 106.7°E) and Tirunelveli (8.7°N, 77.8°E) during the years 1993–1999 are examined in this work. Monthly estimates of tidal amplitudes in the meridional direction over these sites reveal a pronounced interannual variability. The satellite derived Outgoing Longwave Radiation (OLR) is used as a proxy for deep tropical convection in this study. Removal of composite seasonal cycle yields ‘anomalies’ in the diurnal tide over Jakarta and Tirunelveli that are correlated with the OLR anomalies over the western Pacific region (∼120°E). It is suggested that the lower atmospheric large‐scale convective systems originating over the western Pacific region in response to the El Nino Southern Oscillation (ENSO) facilitate excitation of nonmigrating tides through latent heat release or large‐scale redistribution of water vapor that compete with the dominant migrating tide and possibly induce the observed interannual variability in the diurnal tide.