Ship-based estimates of momentum transfer coefficient over sea ice and recommendations for its parameterization
Ship-based estimates of momentum transfer coefficient over sea ice and recommendations for its parameterization
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DOI：
10.5194/acp-2021-705
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发表时间：
2021-10
影响因子：
6.3
通讯作者：
Piyush Srivastava;I. Brooks;J. Prytherch;D. Salisbury;A. Elvidge;I. Renfrew;M. Yelland
中科院分区：
文献类型：
--
作者：
Piyush Srivastava;I. Brooks;J. Prytherch;D. Salisbury;A. Elvidge;I. Renfrew;M. Yelland
抽象。气候预测和海冰季节性预报的不确定性的一个主要来源是地表-大气交换过程的代表性不足。观测需要提高理解和减少不确定性的表面交换参数化是具有挑战性的，使和罕见的。在这里，我们提出了一个大型数据集的船舶测量的表面动量交换（表面阻力）在附近的海冰从北极云夏季实验（ACSE）在2014年7月至10月，和北冰洋2016年实验（AO 2016）在2016年8月至9月。综合数据集提供了一个广泛的记录的动量通量在广泛的表面条件跨越夏末融化和初秋冻结期，以及广泛的大气稳定性。地面交换系数估计从现场涡度相关测量。通过自动处理船载摄像机的图像来确定当地海冰的比例。表面阻力系数CD 10 n在当地冰分数为0.6-0.8时达到峰值，与最近的飞机观测和理论一致。两个国家的最先进的参数化已经调整到我们的观察，都提供了很好的适合的测量。
Abstract. A major source of uncertainty in both climate projections and seasonal forecasting of sea ice is inadequate representation of surface–atmosphere exchange processes. The observations needed to improve understanding and reduce uncertainty in surface exchange parameterizations are challenging to make and rare. Here we present a large dataset of ship-based measurements of surface momentum exchange (surface drag) in the vicinity of sea ice from the Arctic Clouds in Summer Experiment (ACSE) in July–October 2014, and the Arctic Ocean 2016 experiment (AO2016) in August–September 2016. The combined dataset provides an extensive record of momentum flux over a wide range of surface conditions spanning the late summer melt and early autumn freeze-up periods, and a wide range of atmospheric stabilities. Surface exchange coefficients are estimated from in situ eddy covariance measurements. The local sea-ice fraction is determined via automated processing of imagery from ship-mounted cameras. The surface drag coefficient, CD10n, peaks at local ice fractions of 0.6–0.8, consistent with both recent aircraft-based observations and theory. Two state-of-the-art parameterizations have been tuned to our observations with both providing excellent fits to the measurements.