Air-sea interaction
Air-sea interaction
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DOI：
10.1007/978-3-642-13914-7_7
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
W. Lau;D. Waliser;H. Hendon
中科院分区：
文献类型：
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作者：
W. Lau;D. Waliser;H. Hendon
与热带季节内变率(ISV)，特别是与马登-朱利安涛动(MJO)有关的海-气相互作用令人感兴趣，原因有三。首先，海气热通量和水汽通量的变化可能是热带ISV机制的基础。例如，在印度夏季风中，海气相互作用可能促进MJO的缓慢东传和北传。除了在对流和动力学之间的相互作用中发挥关键作用外，地表热量、水汽和动量通量还驱动海表面温度(SST)扰动，这些扰动可能反馈到地表通量并最终反馈到大气动力学，因此，例如，有助于MJO的增长。其次，大气ISV驱动的表层动量、热量和淡水通量的阶段性变化可能在热带印度洋和太平洋暖池的维持和低频变化中起作用。例如，MJO在赤道西太平洋诱导的输送平均从暖池中移走的热量与平均表面热通量提供的热量大致相同(Ralph等人，1997年)。从海洋驱动大气的相反角度来看，暖池SST的年际变化也可能驱动MJO活动的年际变化，这可能与预测MJO活动的季节变化的能力有关。第三，MJO强迫表面流驱动暖池东部边缘的海温变化(例如，Kessler等人，1995)。MJO也有效地激发了开尔文波(例如，Hendon等人，1998)，它辐射到东太平洋，在那里它们可以扰动SST(例如，Giese和Harison，1991；Zhang，2001；McPhaden，2002)。这些季节内海温的变化可能导致一个整流的耦合响应，这在厄尔尼诺南方涛动(ENSO)的演变中起到了作用(例如，Bergman等人，2001；Zhang和Gottschalck，2002)。
Air—sea interaction associated with tropical intraseasonal variability (ISV) and, particularly, the Madden—Julian Oscillation (MJO) is of interest for three reasons. First, variations of the air—sea fluxes of heat and moisture may be fundamental to mechanisms of tropical ISV. For instance, air—sea interaction may promote the slow eastward propagation of the MJO and its northward propagation in the Indian summer monsoon. Besides playing a critical role for the interplay between convection and dynamics, surface fluxes of heat, moisture, and momentum drive sea surface temperature (SST) perturbations that may feedback to the surface fluxes and ultimately to the atmospheric dynamics, thus, for instance, contributing to the growth of the MJO. Second, the episodic variations of surface momentum, heat, and freshwater fluxes driven by atmospheric ISV may play a role in the maintenance and low-frequency variability of the warm pool in the tropical Indian and Pacific Oceans. For example, the MJO induces transports in the equatorial west Pacific that act in the mean to remove about the same amount of heat from the warm pool as is provided by the mean surface heat flux (Ralph et al., 1997). From the opposite perspective of the ocean driving the atmosphere, interannual variations of SST in the warm pool may also drive interannual variations in MJO activity, which may bear on the ability to predict seasonal variations of MJO activity. Third, the MJO forces surface currents that drive SST variations at the eastern edge of the warm pool (e.g., Kessler et al., 1995). Kelvin waves are also efficiently excited by the MJO (e.g., Hendon et al., 1998), which radiate into the eastern Pacific where they can perturb the SST (e.g., Giese and Harrison, 1991; Zhang, 2001; McPhaden, 2002). These intraseasonal SST variations may lead to a rectified coupled-response, which plays a role in the evolution of the El Niño Southern Oscillation (ENSO) (e.g., Bergman et al, 2001; Zhang and Gottschalck, 2002).