The diurnal cycle of lower boundary-layer wind in the West African monsoon
The diurnal cycle of lower boundary-layer wind in the West African monsoon
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DOI：
10.1002/qj.536
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发表时间：
2010-01-01
影响因子：
8.9
通讯作者：
Lebel, Thierry
中科院分区：
文献类型：
--
作者：
Abdou, Kassimou;Parker, Douglas J.;Lebel, Thierry
介绍了非洲季风多学科分析 (AMMA) 期间从四个声波探测和测距 (SODAR) 系统收集的下边界层风的测量结果。SODAR 位于尼亚美附近的中尺度网络中。尼日尔。在2006年5月31日至8月17日期间，该网络至少从一台SODAR获得了41天的良好测量数据，而在一些粘土中，两台或更多SODAR同时产生了良好的数据。这里列出了下边界层风的平均变化。作为高度和一天中的时间的函数 结果证实了先前对风的昼夜周期的研究，并量化了该昼夜周期随高度损失、海拔高度的变化。观察到明显的夜间低空急流。海拔 200-400 m 所有采样日的剖面图平均值。风切变峰值出现在300 m以下层，0000-0600UTC风切变最强，特别是低空风切变震级较大。这对航空来说是一个重大危险，并且强烈依赖于一天中的不同时间强低空风切变（每 100 m 超过 4 m s(-1)）。在 0000-0300 UTC 期间，超过 35% 的天数被观测到。版权所有 (C) 2009 英国皇家气象学会
Measurements of lower boundary-layer winds collected from four Sonic Detection And Ranging (SODAR) systems during the African Monsoon Multidisciplinary Analysis (AMMA) are presented The SODARs were located in a mesoscale network in the vicinity of Niamey. Niger. in the period 31 May to 17 August 2006, from this network 41 days of good measurements have been obtained from at least one of the SODARs, while there are several clays in which two or more SODARs produced good simultaneous data The average variation of the winds in the lower boundary layer is here presented. as a function of height and of time of day The results confirm previous studies of the diurnal cycle of winds, and quantify the variation of this diurnal cycle with height at loss, altitudes On many malus. a distinct nocturnal low-level Jet was observed. at 200-400 m altitude In profiles averaged over all of the sample days. the peak wind shear was in the layer below 300 m, with the strongest wind shear from 0000 to 0600 UTC In particular, the magnitude of low-level wind shear. which is a significant hazard for aviation, is shown to be strongly dependent on time of day Strong low-level wind shear (more than 4 m s(-1) per 100 m). was observed on more than 35% of days in the 0000-0300 UTC period Copyright (C) 2009 Royal Meteorological Society