Aircraft-based observations of air-sea turbulent fluxes around the British Isles
Aircraft-based observations of air-sea turbulent fluxes around the British Isles
复制标题
基于飞机对不列颠群岛周围海空湍流通量的观测
DOI：
10.1002/qj.2345
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发表时间：
2014
影响因子：
8.9
通讯作者：
Cook P
中科院分区：
文献类型：
--
作者：
Cook P
从低层飞机数据的动量，热量和水分的湍流通量的观测。通量是使用涡度协方差技术从通常在海面以上40米的飞行段计算的。超过400运行2分钟（12公里）从26个航班进行评估。飞行航程主要来自不列颠群岛周围，但也有少数来自冰岛和挪威周围。来自两个机载传感器（ARIES干涉仪和Heimann辐射计）的海表面温度（SST）观测值和基于卫星的分析（OSTIA）用于确定改进的SST估计。大多数的观测是从中等到强风的风速条件下，后者是一个制度的验证数据的批量通量算法是必要的数值天气预报和气候模式。静态稳定和不稳定的大气边界层条件下的观测。特别关注DIAMET（对流层外风暴中非绝热对中尺度结构的影响）项目的几次飞行，观测到的中性交换系数与以前的研究相同，尽管动量系数较高，并且与COARE 3.0整体通量算法以及ECMWF和气象局模式中使用的地面交换方案基本一致。将结果作为飞机航向的函数进行检查，结果表明，与沿着风相比，横风向的通量和交换系数更高（尽管这种比较受到相对较少的沿着风段的限制）。多分辨率谱分解技术表明，在沿着风支中，沿着风方差的空间尺度变长，这意味着边界层涡旋在沿着风向上被拉长。沿着风运行可能无法充分捕获正在发生的湍流交换的全部范围，因为伸长将最大涡流置于运行长度之外。
Observations of turbulent fluxes of momentum, heat and moisture from low‐level aircraft data are presented. Fluxes are calculated using the eddy covariance technique from flight legs typically ∼40 m above the sea surface. Over 400 runs of 2 min (∼12 km) from 26 flights are evaluated. Flight legs are mainly from around the British Isles although a small number are from around Iceland and Norway. Sea‐surface temperature (SST) observations from two on‐board sensors (the ARIES interferometer and a Heimann radiometer) and a satellite‐based analysis (OSTIA) are used to determine an improved SST estimate. Most of the observations are from moderate to strong wind speed conditions, the latter being a regime short of validation data for the bulk flux algorithms that are necessary for numerical weather prediction and climate models. Observations from both statically stable and unstable atmospheric boundary‐layer conditions are presented. There is a particular focus on several flights made as part of the DIAMET (Diabatic influence on mesoscale structures in extratropical storms) project.Observed neutral exchange coefficients are in the same range as previous studies, although higher for the momentum coefficient, and are broadly consistent with the COARE 3.0 bulk flux algorithm, as well as the surface exchange schemes used in the ECMWF and Met Office models. Examining the results as a function of aircraft heading shows higher fluxes and exchange coefficients in the across‐wind direction, compared to along‐wind (although this comparison is limited by the relatively small number of along‐wind legs). A multi‐resolution spectral decomposition technique demonstrates a lengthening of spatial scales in along‐wind variances in along‐wind legs, implying the boundary‐layer eddies are elongated in the along‐wind direction. The along‐wind runs may not be able to adequately capture the full range of turbulent exchange that is occurring because elongation places the largest eddies outside of the run length.