Multisensor Estimation of Mixing Heights over a Coastal City
Multisensor Estimation of Mixing Heights over a Coastal City
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DOI：
10.1175/2007jamc1503.1
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发表时间：
2008
影响因子：
3
通讯作者：
J. Nielsen‐Gammon;Christina L. Powell;M. Mahoney;W. Angevine;C. Senff;A. White;C. Berkowitz;C. Doran;K. Knupp
中科院分区：
文献类型：
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作者：
J. Nielsen‐Gammon;Christina L. Powell;M. Mahoney;W. Angevine;C. Senff;A. White;C. Berkowitz;C. Doran;K. Knupp
在德克萨斯州2000年空气质量研究（TexAQS-2000）期间，部署了机载微波温度廓线仪（MTP）来测量边界层热结构。开发并测试了一种客观的技术，用于从MTP垂直温度分布估计混合层（ML）高度。该技术将ML高度识别为边界层内势温从其最小值开始的阈值增加。为了校准该技术并评估该方法的有效性，我们将无线电探空仪、雷达风廓线仪、气溶胶后向散射激光雷达和现场飞机测量结果进行了相互比较，并与MTP进行了比较。所有仪器之间的相对偏差通常小于50 m， MTP ML高度估计值与其他估计值之间的一致性至少与其他估计值之间的一致性一样好。利用MTP和其他仪器估算的ML高度来确定2000年9月1日德克萨斯州休斯顿地区ML高度的时空演变。逆温升高，因此ML生长受到抑制，直到下午早些时候。下午，休斯顿地区的ML高度出现了较大的空间变化。在休斯敦北部观测到的最高ML高度超过2公里，而加尔维斯顿湾下风处和傍晚海风范围内的ML高度要低得多。发现远离沿海环流直接影响的空间变化是意想不到的，多个独立的ML高度估计对于记录这一特征至关重要。
An airborne microwave temperature profiler (MTP) was deployed during the Texas 2000 Air Quality Study (TexAQS-2000) to make measurements of boundary layer thermal structure. An objective technique was developed and tested for estimating the mixed layer (ML) height from the MTP vertical temperature profiles. The technique identifies the ML height as a threshold increase of potential temperature from its minimum value within the boundary layer. To calibrate the technique and evaluate the usefulness of this approach, coincident estimates from radiosondes, radar wind profilers, an aerosol backscatter lidar, and in situ aircraft measurements were compared with each other and with the MTP. Relative biases among all instruments were generally less than 50 m, and the agreement between MTP ML height estimates and other estimates was at least as good as the agreement among the other estimates. The ML height estimates from the MTP and other instruments are utilized to determine the spatial and temporal evolution of ML height in the Houston, Texas, area on 1 September 2000. An elevated temperature inversion was present, so ML growth was inhibited until early afternoon. In the afternoon, large spatial variations in ML height developed across the Houston area. The highest ML heights, well over 2 km, were observed to the north of Houston, while downwind of Galveston Bay and within the late afternoon sea breeze ML heights were much lower. The spatial variations that were found away from the immediate influence of coastal circulations were unexpected, and multiple independent ML height estimates were essential for documenting this feature.