Impacts of Winter Storms on Circulation and Sediment Transport: Atchafalaya-Vermilion Bay Region, Louisiana, U.S.A.
Impacts of Winter Storms on Circulation and Sediment Transport: Atchafalaya-Vermilion Bay Region, Louisiana, U.S.A.
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发表时间：
2000-10
影响因子：
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通讯作者：
N. Walker;A. Hammack
中科院分区：
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作者：
N. Walker;A. Hammack
这项研究调查了伴随着阿查法拉亚湾地区冬季风暴的环流、沉积物再悬浮、沉积物通量和盐度的变化，这些事件每年在10月至4月期间发生20至30次。NOAA-14卫星反射率图像和对风、水位、流速和浊度的时间序列测量表明，风向和风速是环流、泥沙输送和悬浮泥沙浓度的主要控制因素。东风(发生在62%的情况下)导致富含沉积物的阿查法拉亚河水沿海岸向西流动。西风逆转了羽流的移动方向，增加了羽流的大小，这在一定程度上是埃克曼过程的结果。强烈的北风是冬季风暴的特征，会导致浅水湾(体积的30%-50%)迅速涌入，水位变化超过1米。在这些海湾的向海方向，由于底层沉积物的风浪再悬浮和海湾和内陆架水域的风强迫向海输送，产生了一个大的沉积物羽流(近岸180公里，离岸75公里)。水和泥沙通量主要是向东南方向，暂时扰乱了河水沿海岸向西的流动。在朱砂-布兰奇海湾系统中，西北风最大限度地增加了沉积物的再悬浮和富含沉积物的河流和海湾水向海洋的通量。与风暴有关的沉积物再悬浮和输运降低了这些海湾三角洲发育和沉积的速度，并沿内陆架重新分配沉积物。
This study investigates the changes in circulation, sediment resuspension, sediment flux and salinity that accompany "winter storms" in the Atchafalaya Bay region, events that occur 20 to 30 times each year between October and April. NOAA-14 satellite reflectance imagery and time-series measurements of winds, water levels, current velocity and turbidity demonstrate that wind direction and speed are the major controlling factors for circulation, sediment transport and suspended sediment concentrations. East winds (occurring 62% of the time) induce a westward flow of sediment-laden Atchafalaya river water along the coast. West winds reverse the direction of plume movement and increase the size of the plume, partly as a result of Ekman processes. The strong north winds, characteristic of winter storms, cause rapid flushing from the shallow bays (30-50% of volume) and water level changes in excess of 1 meter. Seaward of these bays, a large sediment plume (180 km alongshore, 75 km offshore) is produced by the wind-wave resuspension of bottom sediments and the wind-forced seaward transport of bay and inner shelf waters. Water and sediment flux is primarily southeastward, temporarily disrupting the westward flow of river water along the coast. In the Vermilion-Cote Blanche Bay system, northwest winds maximize sediment resuspension and the seaward flux of sediment-laden river and bay water. The storm-related sediment resuspension and transport reduces the rapidity of delta development and deposition in these bays and re-distributes sediment along the inner shelf.