Boundary layer structure and decoupling from synoptic scale flow during NAMBLEX
Boundary layer structure and decoupling from synoptic scale flow during NAMBLEX
复制标题
NAMBLEX 期间的边界层结构和天气尺度流的解耦
DOI：
10.5194/acp-6-433-2006
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发表时间：
2005
影响因子：
6.3
通讯作者：
I. Longley
中科院分区：
文献类型：
--
作者：
Namblex;E. Norton;G. Vaughan;J. Methven;H. Coe;B. Brooks;M. Gallagher;I. Longley
本文概述了NAMBLEX野外活动期间观测到的气象和行星边界层结构，以帮助解释化学和气溶胶测量。运动已根据当时的天气情况分为五个阶段。比较气象测量（超高频风廓线仪、多普勒雷达、安装在不同高度塔上的声速计和标准风速计）和ECMWF在10米和1100米的分析，确定了当内边界层与高空天气气流分离的日子。总的来说，除了第一阶段和第四阶段的几天，当风向的日变化意味着海面附近有海风/陆风环流时，这种一致性非常好。在这些时期，在梅斯黑德采样的空气来源不能用欧洲气象中心分析中确定的风的后轨迹准确地表示。风廓线观测提供了边界层结构的详细记录，包括其深度、平均风速和风向的指示。湍流统计已被用于评估在广泛的海洋条件下，由海岸表面阻力增加引起的发展中的内边界层到达采样位置的高度。10 m以下的采样在所有风向和潮汐条件下都会受到海岸线排放源的影响，而15 m以上的采样在实验中采样的任何风向和潮汐高度都不太可能受到影响。
This paper presents an overview of the meteorology and planetary boundary layer structure observed during the NAMBLEX field campaign to aid interpretation of the chemical and aerosol measurements. The campaign has been separated into five periods corresponding to the prevailing synoptic condition. Comparisons between meteorological measurements ( UHF wind profiler, Doppler sodar, sonic aneometers mounted on a tower at varying heights and a standard anemometer) and the ECMWF analysis at 10 m and 1100 m identified days when the internal boundary layer was decoupled from the synoptic flow aloft. Generally the agreement was remarkably good apart from during period one and on a few days during period four when the diurnal swing in wind direction implies a sea/land breeze circulation near the surface. During these periods the origin of air sampled at Mace Head would not be accurately represented by back trajectories following the winds resolved in ECMWF analyses. The wind profiler observations give a detailed record of boundary layer structure including an indication of its depth, average wind speed and direction. Turbulence statistics have been used to assess the height to which the developing internal boundary layer, caused by the increased surface drag at the coast, reaches the sampling location under a wide range of marine conditions. Sampling conducted below 10 m will be impacted by emission sources at the shoreline in all wind directions and tidal conditions, whereas sampling above 15 m is unlikely to be affected in any of the wind directions and tidal heights sampled during the experiment.