Assimilated observations of thermospheric winds, the aurora, and ionospheric currents over Alaska
Assimilated observations of thermospheric winds, the aurora, and ionospheric currents over Alaska
复制标题
DOI：
10.1029/2000ja000135
复制
发表时间：
2001-06
影响因子：
--
通讯作者：
M. Conde;J. Craven;T. Immel;E. Hoch;H. Stenbaek-Nielsen;T. Hallinan;Roger Smith;J. Olson;Wei Sun;L. Frank;J. Sigwarth
中科院分区：
文献类型：
--
作者：
M. Conde;J. Craven;T. Immel;E. Hoch;H. Stenbaek-Nielsen;T. Hallinan;Roger Smith;J. Olson;Wei Sun;L. Frank;J. Sigwarth
我们提出了同时测量的热层风，极光发射，电离层电流在阿拉斯加，从四个独立的仪器。热层（F区）风图是由位于扑克坪的全天空成像法布里-珀罗光谱仪记录的，观测波长为λ630.0 nm。从Polar卫星上的低分辨率可见光成像仪获得了波长为557.7 nm的极光图像。白光全天空极光图像是由位于阿拉斯加扑克平原（65° 07′N，212° 34′E）和卡克托维克（70° 06′N，217° 24′E）的地面全天空相机记录的。最后，电离层F区等离子体对流的东西分量推断使用阿拉斯加子午线链磁强计。这四个数据集的蒙太奇图像，投影到阿拉斯加地区的地理地图。我们研究了1997年2月10日阿拉斯加当地夜间的10个小时。这些蒙太奇说明了在极光，电离层等离子体对流，并在F区域风场的空间结构之间的密切关系。地磁纬向风的垂直切变，经常在午夜前的时间段观测到，被认为与离散极光的赤道向和极向边界有关。我们特别关注的一段时间开始后0900 UT，当一个强切变的纬向风被观察到横扫阿拉斯加南部。磁午夜后，风场主要由极冠“跨极急流”的出现所控制。这压倒了任何与当地极光过程有关的风特征。
We present simultaneous measurements of thermospheric winds, auroral emissions, and ionospheric currents over Alaska, obtained from four separate instruments. Thermospheric (F region) wind maps were recorded by an all-sky imaging Fabry-Perot spectrometer located at Poker Flat and observing at λ630.0 nm. Auroral images at λ557.7 nm were obtained from the low-resolution visible imager on board the Polar satellite. White-light all-sky auroral images were recorded by ground-based all-sky cameras located in Alaska at Poker Flat (65° 07′N, 212° 34′E) and at Kaktovik (70° 06′N, 217° 24′E). Finally, the east-west component of the ionospheric F region plasma convection was inferred using the Alaskan meridian chain of magnetometers. Montage images of these four data sets are presented, projected onto a geographic map of the Alaskan region. We examine a 10-hour period during the Alaskan local nighttime of February 10, 1997. These montages illustrate a close relationship between spatial structures occurring in the aurora, in the ionospheric plasma convection, and in the F region wind field. Latitudinal shear of the geomagnetic zonal wind, often observed in the premidnight time sector, was seen to be associated with both the equatorward and poleward boundaries of the discrete aurora. We focus particularly on a period commencing just after 0900 UT, when a strong shear in the zonal wind was observed to sweep southward across Alaska. After magnetic midnight the wind field was dominated by the emergence of the “cross-polar jet” from the polar cap. This overwhelmed any wind features associated with local auroral processes.