Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS)
Meteorological conditions in the central Arctic summer during the Arctic Summer Cloud Ocean Study (ASCOS)
复制标题
北极夏季云海研究（ASCOS）期间北极中部夏季的气象条件
DOI：
10.5194/acp-12-6863-2012
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发表时间：
2012
影响因子：
6.3
通讯作者：
C. Wheeler
中科院分区：
文献类型：
--
作者：
M. Tjernström;C. Birch;I. Brooks;M. Shupe;P. Persson;J. Sedlar;T. Mauritsen;C. Leck;J. Paatero;M. Szczodrak;C. Wheeler
抽象的。由于缺乏对北极特有的强大反馈机制的了解，对北极迅速变化的气候的理解受到限制。只有通过过程一级的观测才能在这一领域取得进展；这是密集的基于破冰船的活动的动机，例如这里所述的北极夏季云-海洋研究(ASCOS)。然而，详细的实地观测也必须放在更大规模气象学的背景下进行，短期实地活动必须在基本气候状态和由此产生的时间异常的背景下进行分析。为了帮助分析在这次行动中观察到的其他参数或过程，本文概述了天气尺度气象及其在ASCOS现场部署期间的气候异常。它还提供了这次行动中的主要特征的统计分析，如主要气象变量、对流层低层和云的垂直结构，以及地面的能量通量。为了评估ASCOS结果的代表性，我们还将这些特征与早先在北冰洋进行的三次夏季试验中获得的类似观测结果进行了比较：AOE-96、SHEBA和AOE-2001探险。我们发现，这些探险活动具有夏季低对流层的许多重要特征。把ASCOS和之前的探险放在一起，常见的情况是，在混合良好的浅层边界层中出现了大量低层云，并被一场弱到中等强度的逆温层所覆盖，其中水分，有时还有云层顶部，穿透到逆温层的下部。边界层混合很大程度上是由于云顶冷却和随后浮云的翻转造成的。云层可能与地面过程相连，也可能不与地面过程相连，这取决于云和基于地面的边界层的深度以及地面切变和云产生的湍流的相对强度。后者还意味着云层和自由对流层之间通过云顶的卷吸作用而联系在一起。
Abstract. Understanding the rapidly changing climate in the Arctic is limited by a lack of understanding of underlying strong feedback mechanisms that are specific to the Arctic. Progress in this field can only be obtained by process-level observations; this is the motivation for intensive ice-breaker-based campaigns such as the Arctic Summer Cloud-Ocean Study (ASCOS), described here. However, detailed field observations also have to be put in the context of the larger-scale meteorology, and short field campaigns have to be analysed within the context of the underlying climate state and temporal anomalies from this. To aid in the analysis of other parameters or processes observed during this campaign, this paper provides an overview of the synoptic-scale meteorology and its climatic anomaly during the ASCOS field deployment. It also provides a statistical analysis of key features during the campaign, such as key meteorological variables, the vertical structure of the lower troposphere and clouds, and energy fluxes at the surface. In order to assess the representativity of the ASCOS results, we also compare these features to similar observations obtained during three earlier summer experiments in the Arctic Ocean: the AOE-96, SHEBA and AOE-2001 expeditions. We find that these expeditions share many key features of the summertime lower troposphere. Taking ASCOS and the previous expeditions together, a common picture emerges with a large amount of low-level cloud in a well-mixed shallow boundary layer, capped by a weak to moderately strong inversion where moisture, and sometimes also cloud top, penetrate into the lower parts of the inversion. Much of the boundary-layer mixing is due to cloud-top cooling and subsequent buoyant overturning of the cloud. The cloud layer may, or may not, be connected with surface processes depending on the depths of the cloud and surface-based boundary layers and on the relative strengths of surface-shear and cloud-generated turbulence. The latter also implies a connection between the cloud layer and the free troposphere through entrainment at cloud top.
影响因子：
4.6
作者：
J. Sedlar;M. Tjernström;T. Mauritsen;M. Shupe;I. Brooks;P. Persson;C. Birch;C. Leck;A. Sirevaag;M. Nicolaus;M. Nicolaus
通讯作者：
J. Sedlar;M. Tjernström;T. Mauritsen;M. Shupe;I. Brooks;P. Persson;C. Birch;C. Leck;A. Sirevaag;M. Nicolaus;M. Nicolaus