Nyberg Johan, Malmgren Björn A, Winter Amos, Jury Mark R, Kilbourne K Halimeda, Quinn Terrence M
Geological Survey of Sweden, Box 670, SE-751 28 Uppsala, Sweden.
Nature. 2007 Jun 7;447(7145):698-701. doi: 10.1038/nature05895.
Hurricane activity in the North Atlantic Ocean has increased significantly since 1995 (refs 1, 2). This trend has been attributed to both anthropogenically induced climate change and natural variability, but the primary cause remains uncertain. Changes in the frequency and intensity of hurricanes in the past can provide insights into the factors that influence hurricane activity, but reliable observations of hurricane activity in the North Atlantic only cover the past few decades. Here we construct a record of the frequency of major Atlantic hurricanes over the past 270 years using proxy records of vertical wind shear and sea surface temperature (the main controls on the formation of major hurricanes in this region) from corals and a marine sediment core. The record indicates that the average frequency of major hurricanes decreased gradually from the 1760s until the early 1990s, reaching anomalously low values during the 1970s and 1980s. Furthermore, the phase of enhanced hurricane activity since 1995 is not unusual compared to other periods of high hurricane activity in the record and thus appears to represent a recovery to normal hurricane activity, rather than a direct response to increasing sea surface temperature. Comparison of the record with a reconstruction of vertical wind shear indicates that variability in this parameter primarily controlled the frequency of major hurricanes in the Atlantic over the past 270 years, suggesting that changes in the magnitude of vertical wind shear will have a significant influence on future hurricane activity.
自1995年以来，北大西洋的飓风活动显著增加（参考文献1、2）。这种趋势归因于人为引起的气候变化和自然变率，但主要原因仍不确定。过去飓风频率和强度的变化可以为影响飓风活动的因素提供见解，但北大西洋飓风活动的可靠观测仅涵盖过去几十年。在这里，我们利用来自珊瑚和一个海洋沉积岩芯的垂直风切变和海表面温度（该地区主要飓风形成的主要控制因素）的代理记录，构建了过去270年大西洋主要飓风频率的记录。该记录表明，主要飓风的平均频率从18世纪60年代到20世纪90年代初逐渐下降，在20世纪70年代和8年代表现为异常低值。此外，与记录中其他飓风活动高发期相比，1995年以来飓风活动增强的阶段并无异常，因此似乎代表着恢复到正常的飓风活动，而非对海表面温度上升的直接响应。将该记录与垂直风切变的重建结果进行比较表明，该参数的变率在过去270年中主要控制了大西洋主要飓风的频率，这表明垂直风切变强度的变化将对未来飓风活动产生重大影响。
