Influences of the Pacific–Japan Teleconnection Pattern on Synoptic-Scale Variability in the Western North Pacific
Influences of the Pacific–Japan Teleconnection Pattern on Synoptic-Scale Variability in the Western North Pacific
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发表时间：
2013
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通讯作者：
Richard;Y. C.;Li
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作者：
Richard;Y. C.;Li
本文研究了太平洋-日本遥相关型对北太平洋西部天气尺度变率的影响。PJ模式表现出明显的季节内变化，10-50天为主要高峰。在PJ正相期间，WNP中SSV增强，天气波列结构更强、更有组织。然而，这种天气尺度的波列在PJ负相期间大大减弱。对观测资料垂直剖面的分析表明，在正（负）PJ条件下，环境参数通常更（更）有利于天气扰动的增长。用异常大气环流模式进一步验证了观测结果，当模式的夏季平均状态中加入与PJ正（负）相相关的环境异常时，天气尺度波列的增长更快（更慢）。此外，灵敏度实验表明，行星边界层（PBL）的热力学参数在控制WNP天气扰动的发展中起决定性作用。背景pblmoisture的增加（减少），即PJ正（负）相增强（抑制）扰动水汽辐合，从而增强（抑制）与SSV相关的对流加热，导致WNP天气尺度活动增强（减弱）。在PJ正（负）相期间，天气尺度活动的增强（减弱）也可能导致季内TC频率的增强（抑制），这是气旋形成的潜在种子扰动。
This study investigates the influences of the Pacific–Japan (PJ) teleconnection pattern on synoptic-scale variability(SSV) in thewestern NorthPacific (WNP). The PJ patternexhibitssalient intraseasonal variations, with a dominant peak at 10–50 days. During positive PJ phases, strengthened SSV is found in the WNP, with a much stronger and better organized synoptic wave train structure. Such a synoptic-scale wave train, how-ever, is greatly weakened during negative PJ phases. Examination of the vertical profiles of the observational data suggests that environmental parameters are generally more (less) favorable for the growth of synoptic disturbances under positive (negative) PJ conditions. Observational results are further verified with an anomaly atmospheric general circulation model, which reveals faster (slower) growth of the synoptic-scale wave train when the environmental anomalies associated with positive (negative) PJ phases are incorporated into the summer mean state of the model. In addition, sensitivity experiments indicate that thermodynamic parameters of the planetary boundary layer (PBL) play a determining role in controlling the development of synoptic disturbances in the WNP. The increase (de-crease)in backgroundPBLmoistureduringpositive(negative) PJ phasesenhances(suppresses)perturbation moisture convergence and thus the convective heating associated with SSV, leading to strengthened (weakened) synoptic-scale activity in the WNP. Serving as potential seed disturbances for cyclogenesis, the strengthened (weakened) synoptic-scale activity may also contribute to the enhancement (suppression) in intraseasonal TC frequency during positive (negative) PJ phases.