Mechanisms Responsible for the Observed Thermodynamic Structure in a Convective Boundary Layer Over the Hudson Valley of New York State
Mechanisms Responsible for the Observed Thermodynamic Structure in a Convective Boundary Layer Over the Hudson Valley of New York State
复制标题
纽约州哈德逊河谷上空对流边界层中观测到的热力学结构的机制
DOI：
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发表时间：
2017
影响因子：
4.3
通讯作者：
D. Fitzjarrald
中科院分区：
文献类型：
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作者：
J. Freedman;D. Fitzjarrald
我们研究了 2003 年在美国纽约州进行的哈德逊河谷环境气象研究 (HVAMS) 期间观察到的区域高架混合层 (EML) 的案例。之前观察到的 EML 涉及尺度为 10$$^{5}$$5–10$$^{6}$$6 km$$^{2}$$2 的地形域。在这里，我们提出了负责在小得多的空间尺度（<5000 km$$^{2}）$$2）上覆盖基于山谷的对流边界层（CBL）的区域EML的机制的观测证据。利用 HVAMS 期间部署的机载、气球和地面平台的观测结果，我们表明，跨山谷水平平流、沿山谷通道和雾引起的冷空气汇集是纽约州哈德逊河谷上空 EML 和山谷-CBL 耦合的形成和维持的原因。上覆 EML 的上层稳定性限制了山谷 CBL 的增长，这对空气扩散、航空利益和雾预报具有重要意义。
We examine cases of a regional elevated mixed layer (EML) observed during the Hudson Valley Ambient Meteorology Study (HVAMS) conducted in New York State, USA in 2003. Previously observed EMLs referred to topographic domains on scales of 10$$^{5}$$5–10$$^{6}$$6 km$$^{2}$$2. Here, we present observational evidence of the mechanisms responsible for the development and maintenance of regional EMLs overlying a valley-based convective boundary layer (CBL) on much smaller spatial scales (<5000 km$$^{2})$$2). Using observations from aircraft-based, balloon-based, and surface-based platforms deployed during the HVAMS, we show that cross-valley horizontal advection, along-valley channelling, and fog-induced cold-air pooling are responsible for the formation and maintenance of the EML and valley-CBL coupling over New York State’s Hudson Valley. The upper layer stability of the overlying EML constrains growth of the valley CBL, and this has important implications for air dispersion, aviation interests, and fog forecasting.