Gateway to the arctic: Defining the eastern channel of the Bering Strait
Gateway to the arctic: Defining the eastern channel of the Bering Strait
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通往北极的门户：定义白令海峡东部通道
DOI：
10.1016/j.pocean.2023.103052
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发表时间：
2023
影响因子：
4.1
通讯作者：
Prescott, Megan M.
中科院分区：
文献类型：
--
作者：
Zimmermann, Mark;Woodgate, Rebecca A.;Prescott, Megan M.
白令海峡是季节性温暖、相对新鲜且营养丰富的太平洋水域流入北极的唯一门户和海洋学瓶颈，融化冰层，降低盐度，喂养鸟类、哺乳动物和鱼类种群。迪奥梅德群岛将这个小海峡分成两条主要航道，均向北流动（年平均）。美国水域的东部航道也季节性地输送较温暖、较新鲜的阿拉斯加沿岸流。全年原位系泊观测（自 1990 年起每年进行维护）显示（向北）通流流量显着增加，并伴有季节性和年度波动。为了帮助测量和建模水流估计，我们创建了白令海峡东部航道的第一个详细的岸对岸测深表面，将其最窄的横截面（1.8 平方公里）定位在系泊处以南 5-10 公里处，并对整个系泊处的横截面（2.0 平方公里）进行了量化，两者都略大于之前的估计（1.6 平方公里）。旧的（∼1950）和新的（∼2010）测深数据集之间的重叠确定了明显的侵蚀和沉积区域，东部河道的大部分地区已经侵蚀了> 1 m。由于东部河道大部分地区的深度均一~50 m，因此我们量化的 1 m 侵蚀只会略微 (2%) 增加横截面的尺寸。海底的大部分都是坚硬的基质，可能由鹅卵石组成，但我们假设强（~1+结）海底流的摩擦是我们观察到的侵蚀最可能的解释。在较软和淤泥较多的地区，测深显示了潜在的水流影响的额外证据，这些影响以小海底波浪（约 0.5 至约 1.0 米高）和威尔士亲王角沙嘴近海的海岸平行坝的形式出现。威尔士亲王角浅滩的海面有巨大的（约 2 m 高）海底波浪。一条先前未描述的（∼1 至 2 公里宽，∼4 m 深）来源不明的海底通道沿着线性北/南轴出现，覆盖了整个 75 公里的测深表面。这条海底通道的南端靠近三个较大的海底通道的末端，这三个海底通道从附近的诺顿湾向西延伸，表明有一个共同的起源。这些诺顿海峡河道可能是古排水沟，因为它们的东端指向苏厄德半岛入口，据报道那里有大型排水沟，那里存在古冰川，但这些河道的形态也与潮汐河道一致。
The Bering Strait is the sole gateway and an oceanographic bottleneck for the seasonally warm and comparatively fresh and nutrient-rich Pacific waters to flow into the Arctic, melting ice, lowering salinity, and feeding bird, mammal, and fish populations. The Diomede Islands split this small strait into two main channels, both with northward flow (in the annual mean). The eastern channel, in U.S. waters, also seasonally carries the warmer, fresher Alaskan Coastal Current. Year-round in situ mooring observations (in place since 1990 with annual servicing) show a significant flow increase in the (northward) throughflow, along with seasonal and annual fluctuations. To help with measuring and modelling water flow estimates, we created the first detailed shore-to-shore bathymetric surface of the Bering Strait’s eastern channel, located its narrowest cross-section (1.8 km2) as occurring 5–10 km south of the moorings, and quantified the cross-section across the moorings (2.0 km2), both slightly larger than previously estimated (1.6 km2). Overlaps between older (∼1950) and newer (∼2010) bathymetry data sets identified clear areas of erosion and deposition, with much of the eastern channel having eroded by > 1 m. Since the depth is uniformly ∼ 50 m across much of the eastern channel, the 1 m of erosion that we quantified would only slightly (2 %) increase the sizes of the cross-sections. Much of the seafloor is hard substrate and probably composed of cobbles, but we hypothesize that friction from strong (∼1 + knot) seafloor currents is the most likely explanation for the erosion that we observed. In softer and siltier areas, the bathymetry showed additional evidence of potential current impacts in the form of small seafloor waves (∼0.5 to ∼ 1.0 m tall) and a shore-parallel bar offshore of Cape Prince of Wales Spit. There are large (∼2 m tall) seafloor waves seaward of Cape Prince of Wales Shoal. A previously undescribed (∼1 to 2 km wide, ∼4 m deep) seafloor channel of unknown origin occurred along a linear north/south axis for the full 75 km extent of the bathymetric surface. The southern end of this seafloor channel was near the end of three larger seafloor channels extending westerly out of nearby Norton Sound, suggesting a common origin. These Norton Sound channels may be paleodrainages, as their eastern ends point toward Seward Peninsula inlets with large drainages where paleoglaciers were reported to have existed, but the morphology of these channels is also consistent with tidal channels.