Influence of Western North Pacific Tropical Cyclones on Their Large-Scale Environment
Influence of Western North Pacific Tropical Cyclones on Their Large-Scale Environment
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DOI：
10.1175/jas3539.1
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发表时间：
2005-09
影响因子：
3.1
通讯作者：
A. Sobel;S. Camargo
中科院分区：
文献类型：
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作者：
A. Sobel;S. Camargo
作者通过对各大尺度气候变量[大气温度、风、相对涡度、输出长波辐射（OLR）、柱状水汽和海温（SST）]在周时间尺度上对西太平洋热带气旋活动指数[气旋累积能量（ACE）]的滞后回归，研究了西太平洋热带气旋（TCs）对其大尺度环境的影响。在所有的前导和滞后几个月的时间里，在所有的变量中都可以看到指示厄尔尼诺-南方涛动（ENSO）现象的持续、缓慢演变的信号，反映了已知的WNP中tc与ENSO的季节性关系。在此基础上叠加的是更快速发展的信号，有一到两周的领先和滞后，与tc本身直接相关。这些异常包括正低层涡度、负OLR和与异常正ACE相关的高柱水蒸气，这些异常在tc最常形成和发展的地区发现。在同一地区，滞后于ACE一两个星期，因此可能反映了tc对当地环境的影响，发现可能对后期气旋形成的环境产生负面影响的信号。这些信号包括在TC活动的主要区域的海温减少，以及水柱水蒸气的减少和OLR的增加，这可能是也可能不是海温减少的结果。在相同的短时间尺度上，在日期变更线附近和以东的赤道海温增加，这可能与赤道表面西风异常有关。结合ACE和ENSO指数在季节时间尺度上的相关性，表明tc可能在ENSO动力学中发挥积极作用。
The authors investigate the influence of western North Pacific (WNP) tropical cyclones (TCs) on their large-scale environment by lag regressing various large-scale climate variables [atmospheric temperature, winds, relative vorticity, outgoing longwave radiation (OLR), column water vapor, and sea surface temperature (SST)] on an index of TC activity [accumulated cyclone energy (ACE)] on a weekly time scale. At all leads and lags out to several months, persistent, slowly evolving signals indicative of the El Nino– Southern Oscillation (ENSO) phenomenon are seen in all the variables, reflecting the known seasonal relationship of TCs in the WNP to ENSO. Superimposed on this are more rapidly evolving signals, at leads and lags of one or two weeks, directly associated with the TCs themselves. These include anomalies of positive low-level vorticity, negative OLR, and high column water vapor associated with anomalously positive ACE, found in the region where TCs most commonly form and develop. In the same region, lagging ACE by a week or two and so presumably reflecting the influence of TCs on the local environment, signals are found that might be expected to negatively influence the environment for later cyclogenesis. These signals include an SST reduction in the primary region of TC activity, and a reduction in column water vapor and increase in OLR that may or may not be a result of the SST reduction. On the same short time scale, an increase in equatorial SST near and east of the date line is seen, presumably associated with equatorial surface westerly anomalies that are also found. This, combined with the correlation between ACE and ENSO indices on the seasonal time scale, suggests the possibility that TCs may play an active role in ENSO dynamics.