MOSAiC Boundary Layer

MOSAiC 边界层

• 批准号: NE/S002472/1
• 负责人: Ian Brooks
• 金额: $ 38.46万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS002472%2F1
• 关键词: MOSAiC; Boundary; Layer

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) initiative is a major international programme motivated by the rapid changes in Arctic climate observed over the last few decades. This is driven by an accelerated rise in the mean temperature of the Arctic; which is warming at 2-3 times the mean global rate. The most visible change is the dramatic reduction in sea ice extent, particularly of the summer minimum, which is decreasing at a rate of 13% per decade. These rapid changes are the result of a combination of feedback processes - the best known is the ice albedo feedback, whereby the loss of ice exposes the land or sea surface beneath, lowering the area mean albedo and allowing more solar radiation to be absorbed, which warms the surface and enhances ice melt. Other feedbacks relate to the vertical profiles of atmospheric temperature and humidity, cloud properties, and large-scale atmospheric circulation.While climate models also show enhanced warming in the Arctic, they do not reproduce many of the observed details of the change; for example they do not reproduce the very rapid decline in the summer sea ice minimum observed over the last 10 years, and there are big differences between models. This has a significant impact on our ability to predict the future state of climate system. Poor model performance results from multiple leading-order deficiencies in their representation of physical processes in the Arctic system. MOSAiC aims to address these through a large-scale coordinated approach, making simultaneous measurements of the many interdependent processes relevant to climate over a full calendar year. This approach is necessary because of the strong linkages and feedbacks between different parts of the Arctic climate system and the strong seasonality in many processes. The observational campaign will take place on, and around, the icebreaker Polarstern, which will be frozen in at the edge of the pack ice at the end of the summer melt. This provides ready access to both multi-year ice within the pack and to freshly forming ice just outside it. Measurements will be made of all components of the surface energy budget on both the upper and lower sides of the ice, along with ice thickness, temperature, physical properties, topography, and deformation over time. The processes controlling the energy budget, including synoptic-scale forcing, cloud properties, turbulent mixing, and the interactions between them, will be studied in detail. The measurements will be complemented by an extensive modelling programme, spanning a full range from small scale process studies up to global climate modelling.The last study to attempt anything remotely comparable to MOSAiC was the Surface Heat Budget of the Arctic (SHEBA) project, which undertook a much more limited set of measurements over 11 months in 1997-1998. The area where SHEBA took place is now ice-free every summer, emphasising the changes that have taken place since then.This proposal is a core contribution to the atmospheric science component of MOSAiC. We will make detailed measurements of lower atmosphere mean and turbulent dynamics for the duration of the measurement campaign. Several remote sensing systems (Doppler sodar and lidar) will be deployed to make continuous measurements mean wind profiles throughout the boundary layer. Retrievals of the vertical turbulence structure will allow the complex interactions between clouds, the boundary layer, and the surface to be understood and thus the primary controls on the surface energy budget and ice melt and formation to be better represented in models. Such detailed measurements of the vertical dynamic structure of the boundary layer will be unique in the Arctic, no comparable data set exists. In addition to our science they underpin many aspects of MOSAiC science being undertaken by other groups, and are considered essential by the MOSAiC atmospheric science coordinators.

北极气候研究多学科漂流观测站（MOSAiC）倡议是一项重大国际计划，其动机是受过去几十年观察到的北极气候快速变化的推动。这是由于北极平均气温加速上升所致；变暖速度是全球平均速度的 2-3 倍。最明显的变化是海冰范围急剧减少，特别是夏季最低海冰范围，以每十年 13% 的速度减少。这些快速变化是反馈过程组合的结果 - 最著名的是冰反照率反馈，即冰的损失暴露了下面的陆地或海洋表面，降低了区域平均反照率并允许吸收更多的太阳辐射，这加热表面并增强冰的融化。其他反馈涉及大气温度和湿度的垂直剖面、云特性和大规模大气环流。虽然气候模型也显示北极变暖加剧，但它们没有重现许多观察到的变化细节；例如，它们没有重现过去十年中观察到的夏季海冰最小值的快速下降，并且模型之间存在很大差异。这对我们预测气候系统未来状态的能力产生重大影响。模型性能不佳是由于其在北极系统物理过程表示中存在多个主序缺陷所致。 MOSAiC 旨在通过大规模协调方法来解决这些问题，在整个日历年内同时测量与气候相关的许多相互依赖的过程。这种方法是必要的，因为北极气候系统不同部分之间存在密切的联系和反馈，并且许多过程具有很强的季节性。观测活动将在“Polarstern”号破冰船及其周围进行，该破冰船将在夏季融化结束时被冻结在浮冰边缘。这样可以方便地获取包装内的多年冰和包装外新鲜形成的冰。将对冰的上侧和下侧表面能量预算的所有组成部分进行测量，以及冰的厚度、温度、物理特性、地形和随时间的变形。将详细研究控制能量预算的过程，包括天气尺度强迫、云特性、湍流混合以及它们之间的相互作用。这些测量将得到广泛的建模项目的补充，涵盖从小规模过程研究到全球气候建模的各个领域。最后一项尝试与 MOSAiC 相媲美的研究是北极地表热量收支 (SHEBA) 项目，该项目在 1997 年至 1998 年的 11 个月内进行了一组更为有限的测量。 SHEBA 举办的地区现在每年夏天都不会结冰，这强调了自那时以来发生的变化。该提案是对 MOSAiC 大气科学部分的核心贡献。我们将在测量活动期间对低层大气平均和湍流动力学进行详细测量。将部署多个遥感系统（多普勒声雷达和激光雷达）来连续测量整个边界层的平均风廓线。垂直湍流结构的检索将有助于理解云、边界层和地表之间复杂的相互作用，从而在模型中更好地表示对地表能量预算以及冰融化和形成的主要控制。这种对边界层垂直动力结构的详细测量在北极地区是独一无二的，不存在可比较的数据集。除了我们的科学之外，它们还支持其他团体正在进行的 MOSAiC 科学的许多方面，并且被 MOSAiC 大气科学协调员认为是必不可少的。

项目成果

Overview of the MOSAiC expedition: Atmosphere

MOSAiC 探险概述：大气

• DOI: http://dx.10.1525/elementa.2021.00060
• 发表时间: 2022
• 期刊: Elem Sci Anth
• 作者: Shupe M

Low-level jets over the Arctic Ocean during MOSAiC

MOSAiC 期间北冰洋上空的低空急流

• DOI: http://dx.10.1525/elementa.2022.00063
• 发表时间: 2022
• 期刊: Science of the Anthropocene
• 作者: López

Continuous observations of the surface energy budget and meteorology over the Arctic sea ice during MOSAiC

MOSAiC 期间对北极海冰的表面能量收支和气象进行连续观测

• DOI: 10.1038/s41597-023-02415-5
• 发表时间: 2023-08-04
• 期刊: Scientific Data
• 影响因子: 9.8
• 作者: C. Cox;Michael R. Gallagher;M. Shupe;P. Persson;A. Solomon;C. Fairall;T. Ayers;B. Blomquist;I. Brooks;D. Costa;A. Grachev;D. Gottas;J. Hutchings;M. Kutchenreiter;J. Leach;Sara M. Morris;V. Morris;J. Osborn;S. Pezoa;A. Preußer;L. Riihimaki;T. Uttal
• 通讯作者: T. Uttal

Evaluation of Vertical Profiles and Atmospheric Boundary Layer Structure Using the Regional Climate Model CCLM during MOSAiC

MOSAiC 期间使用区域气候模式 CCLM 评估垂直剖面和大气边界层结构

• DOI: http://dx.10.3390/meteorology2020016
• 发表时间: 2023
• 期刊: Meteorology
• 作者: Heinemann G