台风涌浪进入东海形成浪区的空间分布特征

西北太平洋台风外围的涌浪可穿过琉球群岛的海峡传入东海。本文采用1978—2018年的历史资料研究了有效波高2 m及以上的涌浪穿过琉球群岛在东海所形成浪区的空间分布特征。结果表明,沿适当角度的台风外围涌浪主要通过与那国海峡、宫古海峡、边户岬-与路岛水道、奄美-吐噶喇海峡传入东海,其余受到岛屿阻挡。筛选得到的40个台风案例中,宫古海峡入射次数最多,为33次,其次是边户岬-与路岛水道和奄美-吐噶喇海峡,均为17次,与那国海峡为11次。奄美-吐噶喇海峡,宫古海峡、边户岬-与路岛水道和与那国海峡的涌浪入射深度达到最大时分别约为570 km、480 km、380 km和234 km。多元线性回归分析结果表明,登陆型台风和西进型台风10级风半径、台风平均移动速度、入射角度对涌浪入射深度的影响较大,单独台风要素与涌浪入射深度无统计学上的相关性。

Spatial distribution characteristics of typhoon swell in the East China Sea

Swells generated by typhoons in the Northwest Pacific Ocean can pass through the straitsof Ryukyu Islands to the East China Sea. Based on the historical data from 1978 to 2018, the spatial distribution characteristics of swells with significant wave heights more than 2 m propagating into the East China Sea were studied. The results showed that the external swells along proper angles can propagate into the East China Sea through the Yonaguni Strait, Miyako Strait, Manzamo-Yorojima Waterway, and Amami-Tukara Strait, and the rest were blocked by islands. Among the 40 typhoon cases screened, the incidence frequency of Miyako Strait was highest with 33 times, followed by Manzamo-Yorojima Waterway and Amami-Tukara Strait with 17 times and Yonaguni Strait with 11 times. The maximum depths of the incident swell in the Amami-Tukara Strait, Miyako Strait, Manzamo-Yorojima Waterway and the Yonaguni Strait are about 570 km, 480 km, 380 km and 234 km respectively. The results of multiple linear regression analysis show that the radius of whole gale, the average moving speed of typhoon and incident angle have great influences on the incident depth of swell, and there is no statistical correlation between single typhoon element and the depth of incident swell.