Novel, direct observations of ice on Lake Superior during the high ice coverage of winter 2013–2014
Novel, direct observations of ice on Lake Superior during the high ice coverage of winter 2013–2014
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2013-2014 年冬季高冰覆盖期间苏必利尔湖冰的新颖直接观测
DOI：
10.1016/j.jglr.2016.07.026
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发表时间：
2016
影响因子：
2.2
通讯作者：
J. Austin
中科院分区：
文献类型：
--
作者：
D. Titze;J. Austin
在2013-2014年冬季，苏必利尔湖上级盆地经历了创纪录的低气温和创纪录的高冰盖。我们目前的观察，从三个地下系泊提供了一个新的看法，在这个极端的冬天的冰盖。每个系泊设备都带有一组阻尼器，两个站点有ADCP，提供了对大型部分冰层覆盖的湖泊的地下特征和行为的罕见一瞥，包括冰漂移速度，龙骨尺寸和丰度，表面重力波抑制和冰盖下的被动声学。冰漂流速度与附近的风速密切相关，冰速约为风速的4%，风向右侧20°。通过冰龙骨移位顶部地下浮动在西部系泊深度6米定期，并在一个事件高达11米。异常大的信号返回强度在两个ADCP偶尔发生在大致相同的时间在两个地理上不同的位置，但只有在冰盖时期。信号强度随深度的分布表明，这些事件实际上是来自冰盖本身的声音，而不是水中的反射物。从广义上讲，上级湖上的冰盖与海洋冰盖的相似之处比与小湖上的冰盖的相似之处更多。
During the 2013–2014 winter, the Lake Superior basin experienced record-low air temperatures and record-high ice cover. We present observations from three subsurface moorings which provided a novel view of the ice cover during this extreme winter. Each mooring carried a set of thermistors, and two sites had ADCPs, providing a rare glimpse into the subsurface characteristics and behavior of a large, partially ice-covered lake, including ice drift velocity, keel size and abundance, surface gravity wave suppression, and passive acoustics below the ice sheet. Ice drift velocities were well correlated with nearby wind velocities, with ice speeds approximately 4% of the wind speed and 20° to the right of the wind direction. Passing ice keels displaced the top subsurface float at the western mooring to depths of 6 m on a regular basis, and up to 11 m during one event. Anomalously large signal return strength at two ADCPs occurred sporadically at roughly the same time at two geographically separate locations, but only during periods of ice cover. The distribution of signal strength with depth suggests that these events are actually sounds from the ice cover itself, rather than reflectors in the water. Broadly speaking, ice cover on Lake Superior has more in common with oceanic ice cover than with ice cover on small lakes.