Polar mesospheric horizontal divergence and relative vorticity measurements using multiple specular meteor radars
Polar mesospheric horizontal divergence and relative vorticity measurements using multiple specular meteor radars
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DOI：
10.1002/2016rs006225
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发表时间：
2017-07
期刊：
影响因子：
1.6
通讯作者：
J. Chau;G. Stober;C. Hall;M. Tsutsumi;F. Laskar;P. Hoffmann
中科院分区：
文献类型：
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作者：
J. Chau;G. Stober;C. Hall;M. Tsutsumi;F. Laskar;P. Hoffmann
我们提出了第一个水平散度和相对涡度测量极地中层高度从地面测量。我们的技术依赖于结合信息从两个镜面流星雷达（SMR）分开130公里，在极地纬度，特别是在挪威北方的Andenes和Tromsbirds雷达。所得到的数值是在中间层高度直径约为400公里的区域上获得的。时间和垂直分辨率分别为1小时和2公里的高度。该技术不仅允许获得水平风的梯度项，进而用于推导水平散度和相对涡度，而且与单个SMR相比还改进了水平采样。合成数据被用来定性测试的技术，并确定潜在的来源偏差的测量结果。例如，我们发现，如果有一个持续的辐散场，经过许多天的平均，就可以得到一个大的视平均垂直速度。我们提出了一个气候的风场参数从12年的连续观测，并专注于夏季的结果。我们发现，在所有北方夏季的水平散度和相对涡度场的持续的垂直模式。在挪威北方上空，水平散度在1086 km以下主要为正向减小，相对涡度在1088 km以下或以上为负/正。
We present the first horizontal divergence and relative vorticity measurements at polar mesospheric altitudes measured from the ground. Our technique relies on combining information from two specular meteor radars (SMRs) separated 130 km at polar latitudes, specifically, the Andenes and Tromsø radars in northern Norway. The resulting values are obtained over a region that spans an approximate area of 400 km diameter at mesospheric altitudes. The temporal and vertical resolution are 1 h and 2 km in altitude. The technique not only allows to obtain the gradient terms of the horizontal wind, that in turn are used to derive the horizontal divergence and relative vorticity, but also improves the horizontal sampling compared to single SMRs. Synthetic data are used to qualitatively test the technique and identify potential sources of biases on the resulting measurements. For example, we have found that an apparent large mean vertical velocity is obtained, after averaging many days, if there is a persistent divergent field. We present a climatology of the resulting wind field parameters from 12 years of continuous observations and focus on the summer results. We found a persistent altitudinal pattern in both the horizontal divergence and relative vorticity fields during all northern hemispheric summers. The horizontal divergence is mainly positive decreasing in magnitude below ∼86 km, and the relative vorticity is negative/positive below/above ∼88 km over northern Norway.