Material to : Seasonal Versus Permanent Thermocline Warming by Tropical Cyclones
Material to : Seasonal Versus Permanent Thermocline Warming by Tropical Cyclones
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发表时间：
2010
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通讯作者：
M. Jansen;R. Ferrari;T. Mooring
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作者：
M. Jansen;R. Ferrari;T. Mooring
TC冷尾迹的热吸收沿以每6小时最佳轨道位置为中心的横截面计算。对于主要经向移动的风暴（即45°以内），我们计算纬向横截面；对于主要经向移动的风暴，我们计算经向横截面。然后，沿着每6小时横截面的单位面积的吸热量乘以到下一个6小时位置的距离。为了计算总热传输，我们现在需要对整个尾迹进行积分，这就提出了一个问题，即横截面宽度的合适选择是什么。在没有任何海温背景变率的情况下，只要宽度足够大，足以包括整个TC信号，热吸收估计就不会依赖于这种选择。然而，海温的背景变率会使热吸收估计值偏高，尤其是远离尾流中心的地方。原因是，当海表温度下降时，方程(1)和(2)返回一个正的热吸收估计，而当海表温度增加时，则返回零热吸收估计。如果海温异常与风暴的通过有关，这是合适的，但如果海温变化是由背景变率引起的，则不合适。预计背景海温变化不对应于净热吸收，但我们的算法总是返回与冷异常变暖相关的正值和零值
The heat uptake in TC cold wakes is computed along cross-sections centered on each of the 6-hourly Best Track locations. For storms moving predominantly meridionally (i.e. within 45) we compute zonal cross-sections and for storms moving predominantly zonally, we compute meridional cross-sections. The heat uptake per unit area along each 6-hourly cross-section is then multiplied by the distance to the next 6-hourly location. To calculate the total heat transport we now need to integrate across the wake, which poses a question as to what is an appropriate choice for the width of the cross sections. In the absence of any background variability of SST, the heat uptake estimate would not depend on this choice, as long as the width is sufficiently large to include the whole TC signal. However, background variability in SST will bias the heat uptake estimate high, especially far from the wake center. The reason is that equations (1) and (2) return a positive heat uptake estimate whenever there is a decrease in SST, but zero heat uptake when there is an increase in SST. This is appropriate if the SST anomalies are associated with the passage of the storm but not if the SST variations are due to background variability. Background SST variations are not expected to correspond to a net heat uptake, but our algorithm always returns positive values associated with warming of cold anomalies and zero values