Bogen Kenneth T, Jones Edwin D, Fischer Larry E
Energy and Environment Directorate, Lawrence Livermore National Laboratory, University of California, Livermore, CA 94550, USA.
Risk Anal. 2007 Dec;27(6):1497-517. doi: 10.1111/j.1539-6924.2007.00984.x.
Forecasting destructive hurricane potential is complicated by substantial, unexplained intraannual variation in storm-specific power dissipation index (PDI, or integrated third power of wind speed), and interannual variation in annual accumulated PDI (APDI). A growing controversy concerns the recent hypothesis that the clearly positive trend in North Atlantic Ocean (NAO) sea surface temperature (SST) since 1970 explains increased hurricane intensities over this period, and so implies ominous PDI and APDI growth as global warming continues. To test this "SST hypothesis" and examine its quantitative implications, a combination of statistical and probabilistic methods were applied to National Hurricane Center HURDAT best-track data on NAO hurricanes during 1880-2002, and corresponding National Oceanographic and Atmospheric Administration Extended Reconstruction SST estimates. Notably, hurricane behavior was compared to corresponding hurricane-specific (i.e., spatiotemporally linked) SST; previous similar comparisons considered only SST averaged over large NAO regions. Contrary to the SST hypothesis, SST was found to vary in a monthly pattern inconsistent with that of corresponding PDI, and to be at best weakly associated with PDI or APDI despite strong correlation with corresponding mean latitude (R(2)= 0.55) or with combined mean location and a approximately 90-year periodic trend (R(2)= 0.70). Over the last century, the lower 75% of APDIs appear randomly sampled from a nearly uniform distribution, and the upper 25% of APDIs from a nearly lognormal distribution. From the latter distribution, a baseline (SST-independent) stochastic model was derived predicting that over the next half century, APDI will not likely exceed its maximum value over the last half century by more than a factor of 1.5. This factor increased to 2 using a baseline model modified to assume SST-dependence conditioned on an upper bound of the increasing NAO SST trend observed since 1970. An additional model was developed that predicts PDI statistics conditional on APDI. These PDI and APDI models can be used to estimate upper bounds on indices of hurricane power likely to be realized over the next century, under divergent assumptions regarding SST influence.
预测具有破坏性的飓风潜力很复杂,因为特定风暴的功率耗散指数(PDI,即风速的三次方积分)存在大量无法解释的年内变化,以及年累计PDI(APDI)的年际变化。一个日益激烈的争议涉及最近的假设,即自1970年以来北大西洋(NAO)海表面温度(SST)明显的正趋势解释了这一时期飓风强度的增加,因此意味着随着全球变暖的持续,PDI和APDI将出现不祥的增长。为了检验这个“SST假设”并研究其定量影响,将统计和概率方法相结合,应用于1880 - 2002年期间国家飓风中心关于北大西洋飓风的HURDAT最佳路径数据,以及相应的美国国家海洋和大气管理局扩展重建SST估计值。值得注意的是,将飓风行为与相应的特定飓风(即时空相关)SST进行了比较;以前类似的比较仅考虑了北大西洋大区域平均的SST。与SST假设相反,发现SST的月度变化模式与相应的PDI不一致,并且尽管与相应的平均纬度(R² = 0.55)或与平均位置和大约90年的周期性趋势的组合(R² = 0.70)有很强的相关性,但与PDI或APDI的相关性至多很弱。在过去的一个世纪里,75%较低的APDI似乎是从几乎均匀的分布中随机抽样得到的,而25%较高的APDI是从几乎对数正态分布中抽样得到的。从后一种分布中,推导出了一个基线(与SST无关)的随机模型,预测在接下来的半个世纪里,APDI不太可能超过上半个世纪的最大值的1.5倍。使用一个修改后的基线模型,假设SST依赖性基于自1970年以来观测到的北大西洋SST上升趋势的上限,这个因子增加到了2。还开发了一个额外的模型,该模型根据APDI预测PDI统计数据。这些PDI和APDI模型可用于估计在下个世纪,在关于SST影响的不同假设下可能实现的飓风功率指数的上限。