Extreme Variability in Irminger Sea Winter Heat Loss Revealed by Ocean Observatories Initiative Mooring and the ERA5 Reanalysis
Extreme Variability in Irminger Sea Winter Heat Loss Revealed by Ocean Observatories Initiative Mooring and the ERA5 Reanalysis
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DOI：
10.1029/2018gl080956
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发表时间：
2019-01-16
影响因子：
5.2
通讯作者：
Weller, R. A.
中科院分区：
文献类型：
--
作者：
Josey, S. A.;de Jong, M. F.;Weller, R. A.
开创性的测量，从海洋观测站倡议Irminger海面停泊（60度N，39度30 W），提供了第一个在高纬度北大西洋站点的多冬季表面热交换的原位表征。它们揭示了强烈的变异性（2014年12月的净热损失比2015年12月高出近50%），主要是由于强烈的短时间尺度（1- 3天）强迫的频率变化。将观测结果与新的高分辨率欧洲中期天气预报再分析中心5（ERA 5）大气再分析相结合，多冬季变率的主要来源是格陵兰尖端急流频率的变化（2014年12月有15天，2015年12月有30天），这可能导致每小时平均热损失超过800 W/m（2）。此外，一个新的图片大气模式的影响Irminger海热量损失的发展，即强烈的积极北大西洋涛动条件有利于增加损失时，只有不超过东大西洋Pattern.Plain语言摘要海洋失去热量的大气中的远北方大西洋。这一点很重要，因为热量损失会影响形成多少深水和大西洋环流的强度。然而，人们对热量损失的数量知之甚少，因为在副极地海洋冰冷、大风的条件下很难进行测量。这里介绍了格陵兰岛东部Irminger海最先进的系泊设备的新测量结果。它们是在如此高纬度地区获得的第一个多冬季测量结果，揭示了海洋热量损失的强烈变化。这种变化是由于冬季之间的强烈热损失事件数量的变化。这些事件是由格陵兰多山的地形造成的，格陵兰的地形将风集中在海洋上空的狭窄，非常强烈的射流中。我们开发了一个新的图片，解释了如何改变大气环流影响事件的数量，从而海洋热损失。
Ground-breaking measurements from the ocean observatories initiative Irminger Sea surface mooring (60 degrees N, 39 degrees 30W) are presented that provide the first in situ characterization of multiwinter surface heat exchange at a high latitude North Atlantic site. They reveal strong variability (December 2014 net heat loss nearly 50% greater than December 2015) due primarily to variations in frequency of intense short timescale (1-3days) forcing. Combining the observations with the new high resolution European Centre for Medium Range Weather Forecasts Reanalysis 5 (ERA5) atmospheric reanalysis, the main source of multiwinter variability is shown to be changes in the frequency of Greenland tip jets (present on 15days in December 2014 and 3days in December 2015) that can result in hourly mean heat loss exceeding 800W/m(2). Furthermore, a new picture for atmospheric mode influence on Irminger Sea heat loss is developed whereby strongly positive North Atlantic Oscillation conditions favor increased losses only when not outweighed by the East Atlantic Pattern.Plain Language Summary The ocean loses heat to the atmosphere in the far northern Atlantic. This is important as heat loss influences how much deep water is formed and the strength of the Atlantic circulation. However, the amount of heat lost is poorly known because measurements are difficult to obtain in the icy, high wind conditions of the subpolar seas. New measurements from a state-of-the-art mooring in the Irminger Sea east of Greenland are presented here. They are the first multiwinter measurements obtained at such high latitudes and reveal strong variability in ocean heat loss. This variability is due to changes between winters in the number of intense heat loss events. The events are caused by the mountainous Greenland terrain which focuses winds into narrow, very strong jets over the ocean. We develop a new picture which explains how changing atmospheric circulation influences the number of events and hence the ocean heat loss.