Creation and tidal advection of a cold salinity front in Storfjorden: 1. Polynya dynamics
Creation and tidal advection of a cold salinity front in Storfjorden: 1. Polynya dynamics
复制标题
Storfjorden 冷盐锋的产生和潮汐平流：1. 冰间湖动力学
DOI：
10.1002/jgrc.20231
复制
发表时间：
2013
影响因子：
--
通讯作者：
L. Smedsrud
中科院分区：
文献类型：
--
作者：
R. Skogseth;M. Mcphee;F. Nilsen;L. Smedsrud
[1]水文测量从Storfjorden冰间湖文件存在一个突然的前在近冰点的水划分盐水最近创建的冰间湖事件，从少盐水起源进一步南部。这一事件发生在调查的前几天，估计冰穴上方的热通量为400 W m−2。富盐水陆架水（BSW）观察到下坡向更深的部分Storfjorden，和BSW从早期冰间湖事件溢出的窗台。附近的Freemansundet海峡的海流测量记录了超过80 cm s-1的潮汐流，这些潮汐流使测量点下方距离冰穴边缘约400米的固定冰上的锋面来回移动。记录到的锋面位移为1.12 km，主要是由于M2分量叠加在调查期间南风引起的声音中的0.28 m s−1的平均余流上。复杂的地形造成斜压潮流，在快速冰覆盖的声音中具有强烈的垂直切变，并具有显著的跨通道流动。水文时间序列中的过冷事件，并可能增强frazil冰生产，与双扩散湍流混合时，盐度前通过。通过这种方式，这些测量结果表明，一种新的冰生产过程沿着潮汐诱导潜热冰穴的边缘，盐度锋的产生。在涨潮（落潮）时，由于盐度锋通过测量点时水柱的不稳定（稳定），湍流增加（减少）。双扩散湍流混合有关的潮汐平流的盐度锋下快冰追求的一个配套文件。
[1] Hydrographical measurements from the Storfjorden polynya document the presence of an abrupt front in near-freezing water dividing saline water recently created by a polynya event, from less saline water originating further south. This event occurred days before the survey with estimated heat flux ∼400 W m−2 over the polynya. Brine-enriched shelf water (BSW) is observed downslope toward deeper parts of Storfjorden, and BSW from earlier polynya events overflows the sill. Current measurements from a nearby sound, Freemansundet, document tidal currents exceeding 80 cm s−1 that displaced the front back and forth beneath the measurement site on fast ice ∼400 m from the polynya edge. Front displacement of ∼12 km is documented and mainly due to the M2 component superimposed on a mean residual current of 0.28 m s−1 into the sound induced by southerly wind during the survey. Complex topography imposes baroclinic tidal currents with strong vertical shear in the fast ice-covered sound, and with significant cross-channel flow. Supercooling events indicated in the hydrographical time series, and likely enhanced frazil ice production, are associated with double-diffusive turbulent mixing when the salinity front passes. In this way, these measurements indicate a novel ice production process along the edge of tidally induced latent heat polynyas where salinity fronts are generated. Turbulence increases (decreases) during flood (ebb) due to the destabilization (stabilization) of the water column when the salinity front passes the measurement site. Double-diffusive turbulent mixing related to tidal advection of salinity front below fast ice is pursued in a companion paper.