Atmospheric Response to Kilometer-Scale Changes in Sea Ice Concentration Within the Marginal Ice Zone
Atmospheric Response to Kilometer-Scale Changes in Sea Ice Concentration Within the Marginal Ice Zone
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DOI：
10.1029/2018gl078295
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发表时间：
2018-07-16
影响因子：
5.2
通讯作者：
Mueller, Malte
中科院分区：
文献类型：
--
作者：
Batrak, Yurii;Mueller, Malte
海冰千米尺度特征在天气和气候模式系统中没有明确表示。然而，由于海冰和海洋之间的表面温度差异很大，海冰无冰区（lead、polynyas等）可以对表面热通量产生强烈影响，进而对大气动力学产生强烈影响。本研究分析了在弗拉姆海峡和巴伦支海边缘冰带，大气对海冰特征变化的响应。采用千米尺度的对流允许大气模拟系统。模型敏感性实验是理想化的，因为在这些尺度上没有关于海冰的完整信息。相反，我们将海冰浓度的被动微波卫星产品信息与基于热红外传感器的海冰铅产品合并。一个重要的限制因素是，海面无冰区域是局部引入的，但在100公里的尺度上，两个实验的海冰覆盖率都是保持不变的。分析了模型试验对海气通量、大气温度和风的敏感性。一般情况下，地表气温和风速变化的标准差在大尺度上分别约为2 K和2 m/s。这些数值与该地区先进天气预报模式的平均12小时预报误差相同。现代天气和气候模式以及再分析产品在极地地区往往存在不足。其中一个问题是海冰空间结构的表征及其与海洋和大气的相互作用。例如，在模式模拟或卫星监测产品中，千米尺度海冰特征的准确性存在问题。目前，在大多数大气模拟系统中，海冰覆盖被表示为一个相对平滑的场，因此预计将对大气动力学产生重要影响。在本研究中，我们使用高分辨率数值天气预报系统来研究海冰浓度中千米尺度特征的存在对大气的影响。我们通过将粗分辨率海冰浓度产品与专用的细分辨率海冰铅产品相结合来介绍这些产品。主要目的是分析对近地表温度和风的影响范围和强度。研究表明，在距离海冰边缘500- 1000公里的地区，这种影响是显著的。这种影响与12小时预报的预报精度一样大，意味着它将有利于模式应用，以提高我们监测和模拟海冰铅特征的能力。
Sea ice kilometer-scale characteristics are not explicitly represented in weather and climate model systems. However, due to the large differences of the surface temperature between sea ice and ocean, sea ice-free areas (leads, polynyas, etc.) can have a strong impact on the surface heat fluxes and, in turn, on atmospheric dynamics. In the present study we analyze the atmospheric response to changes in the sea ice characteristics in the marginal ice zone of the Fram Strait and Barents Sea. A kilometer-scale convection permitting atmospheric modeling system is used. The model sensitivity experiment is idealized, since there is no complete information on sea ice on these scales available. Instead, we are merging information from the passive microwave satellite product of sea ice concentration with a sea ice lead product based on thermal infrared sensors. An important constraint is that the sea ice-free areas are introduced locally, but on scales of 100 km the sea ice coverage is kept constant for both the experiments. The sensitivity of air-sea fluxes, atmospheric temperature, and winds is analyzed between the model experiments. In general, the standard deviation of the changes in surface air temperature and winds is, on large scales, about 2 K and 2 m/s, respectively. Those values are in the same order as the mean 12-hr forecast error of advanced weather forecast models in this region.Plain Language Summary Modern weather and climate models as well as reanalysis products tend to have deficiencies in polar regions. One of the issues is the representation of the spatial structure of sea ice and its interaction with the ocean and atmosphere. For example, there are problems in accuracy of kilometer-scale sea ice characteristics in model simulations or satellite monitoring products. Currently, in most of atmospheric modeling systems, the sea ice cover is represented as a relatively smooth field, therefore expected to have important consequences for the atmospheric dynamics. In the present study we use a high-resolution numerical weather prediction system to study the effect of presence of kilometer-scale features in sea ice concentration on the atmosphere. We introduce these by combining a coarse resolution sea ice concentration product with a dedicated fine resolution sea ice lead product. The main objective is to analyze the impact range and strength of the effect on near-surface temperature and wind. The study shows that impact is significant in areas up to 500-1,000 km away from the sea ice edge. This impact, as large as the forecast accuracy of a 12-hr forecast, implies that it will be beneficial for model applications to improve our capabilities in monitoring and simulating of sea ice lead characteristics.