First ground-based optical analysis of H β Doppler profiles close to local noon in the cusp
First ground-based optical analysis of H β Doppler profiles close to local noon in the cusp
复制标题
首次对接近当地正午的尖点 H β 多普勒轮廓进行地面光学分析
DOI：
10.5194/angeo-24-2543-2006
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Baumgardner
中科院分区：
文献类型：
--
作者：
S. Robertson;B. Lanchester;M. Galand;D. Lummerzheim;A. Stockton;A. Aylward;I. Furniss;J. Baumgardner
抽象的。本文利用朗伊尔城磁顶（78.2 N，15.8 E）氢发射沿着观测资料，研究了高纬地区质子的能量和来源。在当地太阳正午（11：00 UT）附近的几个小时内，氢巴耳末β线的测量受到阳光的严重影响，因此到目前为止，大多数数据在这些时间内都被忽略了。在这里，我们使用一个简单的技术，以减去阳光污染从这样的光谱数据。一个例子显示，黄昏污染的去除揭示了在2000年11月27日08：00 UT和10：00 UT之间的斯瓦尔巴特群岛上空的Hβ极光的增亮，这是集中在磁中午（08：48 UT）。这些数据是由南安普敦-伦敦大学学院光谱成像设施（SIF）上的一种仪器--高发射量成像中阶梯光谱仪（HiTIES）测量的。来自IMAGE卫星的数据证实了地面测量时斯瓦尔巴群岛上空一个尖点的位置，该位置随着IMF条件的变化而移动。DMSP F12卫星的一次重合通过为Hβ剖面的建模研究提供了输入光谱，这证实了消除曙暮光污染的方法是可靠的。这里描述的结果是第一次从接近当地太阳正午的尖点区域对Hβ多普勒剖面进行地面光学测量，当时散射的阳光淹没了原始数据。
Abstract. Observations of hydrogen emissions along the magnetic zenith at Longyearbyen (78.2 N, 15.8 E geographic) are used to investigate the energy and source of protons precipitating into the high latitude region. During the hours around local solar noon (11:00 UT), measurements of the hydrogen Balmer β line are severely affected by sunlight, such that most data until now have been disregarded during these times. Here we use a simple technique to subtract sunlight contamination from such spectral data. An example is shown in which the removal of twilight contamination reveals a brightening of Hβ aurora over Svalbard on 27 November 2000 between 08:00 UT and 10:00 UT, which is centred on magnetic noon (08:48 UT). These data were measured by the High Throughput Imaging Echelle Spectrograph (HiTIES), one instrument on the Southampton-UCL Spectrographic Imaging Facility (SIF). Data from the IMAGE satellite confirms the location of a cusp "spot" over Svalbard at the time of the ground-based measurements, which moved in response to changes in the IMF conditions. A coincident pass of the DMSP F12 satellite provided input spectra for modelling studies of the Hβ profiles, which confirm that the method for removing the twilight contamination is robust. The results described here are the first ground-based optical measurements of Hβ Doppler profiles from the cusp region close to local solar noon, when scattered sunlight swamps the raw data.