Can VHF radars at polar latitudes measure mean vertical winds in the presence of PMSE?
Can VHF radars at polar latitudes measure mean vertical winds in the presence of PMSE?
复制标题
在存在 PMSE 的情况下，极地纬度的 VHF 雷达能否测量平均垂直风？
DOI：
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发表时间：
2019
影响因子：
6.3
通讯作者：
J. Chau
中科院分区：
文献类型：
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作者：
N. Gudadze;G. Stober;J. Chau
抽象的。从极地纬度的雷达获得的平均垂直速度测量值
使用极地中间层夏季回波（PMSE）作为惰性示踪剂
被认为不代表过去的平均垂直风
几十年了。我们使用在中层大气 Alomar 观测到的 PMSE
挪威安岛 (69.30∘ N,
16.04∘ E），在 2016 年和 2017 年夏季期间得出平均垂直
中层上层的风。 3-D 矢量风分量（纬向、
经向和垂直）基于多普勒光束摆动实验
使用五个光束方向（一个垂直，四个倾斜）。 3D风
使用最近开发的风检索技术来计算分量。
该方法包括完全非线性误差传播、空间和时间
正则化、光束指向校正和角度指向
不确定性。使用测量不确定度作为权重来获得
季节性加权平均值并表征季节性平均垂直
速度。垂直速度的加权平均值显示出较弱的
消除后在海拔约 84–87 km 处的向上行为
落冰速度的影响。与此同时，急剧下降
下（上）边缘的平均垂直速度（增加）
夏季平均海拔剖面，这归因于采样问题
由于对应于特定目标的消失而导致的 PMSE
运动和温度区域占主导地位。因此平均垂直
速度可以在下边缘向下偏置，并且平均垂直
速度可以在上边缘向上偏，而在主要中心
区域中获得的平均垂直速度与预期一致
考虑冰粒后平均垂直风的向上值
沉淀。
Abstract. Mean vertical velocity measurements obtained from radars at polar latitudes
using polar mesosphere summer echoes (PMSEs) as an inert tracer have been
considered to be non-representative of the mean vertical winds over the last
couple of decades. We used PMSEs observed with the Middle Atmosphere Alomar
Radar System (MAARSY) over Andøya, Norway (69.30∘ N,
16.04∘ E), during summers of 2016 and 2017 to derive mean vertical
winds in the upper mesosphere. The 3-D vector wind components (zonal,
meridional and vertical) are based on a Doppler beam swinging experiment
using five beam directions (one vertical and four oblique). The 3-D wind
components are computed using a recently developed wind retrieval technique.
The method includes full non-linear error propagation, spatial and temporal
regularisation, and beam pointing corrections and angular pointing
uncertainties. Measurement uncertainties are used as weights to obtain
seasonal weighted averages and characterise seasonal mean vertical
velocities. Weighted average values of vertical velocities reveal a weak
upward behaviour at altitudes ∼84–87 km after eliminating the
influence of the speed of falling ice. At the same time, a sharp decrease
(increase) in the mean vertical velocities at the lower (upper) edges of the
summer mean altitude profile, which are attributed to the sampling issues of
the PMSE due to disappearance of the target corresponding to the certain
regions of motions and temperatures, prevails. Thus the mean vertical
velocities can be biased downwards at the lower edge, and the mean vertical
velocities can be biased upwards at the upper edge, while at the main central
region the obtained mean vertical velocities are consistent with expected
upward values of mean vertical winds after considering ice particle
sedimentation.