|东中国海大陆架常受台风侵扰，强风浪破坏水体结构的同时引起大量泥沙再悬浮，是影响东中国海表层悬沙浓度（SSC）的主要动力之一。本文基于GOCI遥感数据分析不同类型台风事件对表层悬沙浓度时空分布的影响，结果表明近海活动型和远海活动型台风使SSC显著增高了150 %~200 %，随着风速减小，SSC逐渐下降，需要至少3~4天恢复至台风到来前的SSC，风速变化与SSC变化率的相关性高达0.86。近海及远海活动型台风影响研究区域SSC的大风风向为偏北风，该类型台风事件使秋季SSC等值线向外海延伸，出现“舌状”分布特点。登陆型台风事件影响研究区域SSC的大风风向前期为偏北风，后期为偏南风，该类型的台风使SSC等值线基本平行向外海移动较短距离，没有向外海延伸的“舌状”分布。近海及远海活动型台风事件可将SSC分布迅速向“冬季输运”的类型改变，近海活动型台风对SSC分布的影响比远海活动型更显著。登陆型台风对研究区域SSC跨陆架方向分布的影响比远海活动型台风更小。
|关键词: 表层悬沙浓度 GOCI 台风类型 风速
|The effect of typhoon events on the spatio-temporal evolution of suspended sediment concentration in the East China Sea
Zhao Renling1, Zhou Chunyan1, Xu Chunyang1, LIU WEI2
1.Hohai University;2.harbour and waterway Development Center of Lianyungang City
|The continental shelf of the East China Sea is often disturbed by typhoons. Strong winds and waves destroy the water structure and cause a large amount of sediment resuspension, which is one of the main driving forces affecting the concentration of suspended sediment in the surface layer of the East China Sea. Based on GOCI remote sensing data, the influence of typhoon events on the temporal and spatial variation of surface suspended sediment concentration (SSC) distribution in the East China Sea is analyzed. It is found that nearshore and offshore active typhoons can greatly increase SSC by 150% to 200%, and SSC decreases gradually with the decrease of wind speed, and it takes at least 3~4 days to recover back to the SSC pattern before typhoon’s arrival, and the correlation between the change of wind speed and the change rate of SSC is as high as 0.86. The wind direction of typhoon active at offshore and nearshore area is north during active at the study area, and these types of typhoon event obviously change the SSC distribution pattern of Autumn, showing a "tongue" distribution extending to the open sea. The wind of typhoons making landfall affecting the SSC in the study area is northerly in the early stage and southerly in the later stage. This type of typhoon makes the SSC contour move parallel seaward by a short distance, without a "tongue " distribution . The typhoons active at offshore area and nearshore can quickly change the SSC distribution to the type of "winter transport", among them, nearshore active typhoon events have a more significant impact on the distribution of SSC than offshore active typhoons, while the typhoons making landing have less impact on the cross-shelf distribution of SSC than typhoons active at offshore area.
|Key words: surface suspended sediment concentration GOCI typhoon type wind speed