论文标题
火球光谱中的氧气线及其在卫星观测中的应用
Oxygen line in fireball spectra and its application to satellite observations
论文作者
论文摘要
目标。船上天气卫星上的闪电映射传感器可以成功地用于观察火球。这些传感器在777nm处使用非常狭窄的光谱带，这仅是总火球辐射的一小部分。在这个光谱带中，氧O I-1三元组在快速流星中占主导地位，而普朗克连续体可以在慢速流星中占上风。可以估算可见光谱范围内的流星亮度，但首先研究这种辐射对流星速度的依赖性至关重要。方法。我们使用了成熟的欧洲火球网络的观察结果，该网络具有新开发的数字光谱摄像头，使我们能够研究流星光谱中的氧气三重态及其与流星速度和高度的关系。此外，我们研究了强镁和钠线。结果。我们开发了一种校准的方法，该方法是由地球上闪电映射器（GLM）传感器报道的火球观测方法。我们确认，在慢速流星中，普朗克连续体的辐射占主导地位，但是对于更快的流星，需要对速度进行校正。我们观察到记录氧气线的高度也会影响777 nm处的辐射。此外，确定流星是否显示出明亮的耀斑也可能导致类似的效果。因此，流星亮度估计可能会受到这些特征的影响。我们在高度和流星亮度上得出了简单的校正，这有助于提高样品幅度估计的总体精度。这使我们能够估计GLM观察到的流星的大小，其精度约为1。发现Na/mg线强度比对于高于25 km/s的速度是恒定的，并且朝着较低的速度增加。
Aims. Lightning mapper sensors on board weather satellites can be successfully used to observe fireballs. These sensors use a very narrow spectral band at 777nm, which is only a small fraction of the total fireball radiation. In this spectral band, the oxygen O I-1 triplet is dominant for fast meteors and the Planck continuum can prevail in slow meteors. It is possible to estimate the meteor brightness in the visible spectral range from this narrowband radiation, but it is vital to first study the dependence of this radiation on the meteor velocity. Methods. We used observations from the well-established European Fireball Network with newly developed digital spectral cameras that allowed us to study the oxygen triplet in meteor spectra and its relation to the meteor velocity and altitude. In addition, we studied strong magnesium and sodium lines. Results. We developed a method for calibration of fireball observation reported by Geostationary Lightning Mapper (GLM) sensors on board the Geostationary Operational Environmental Satellite (GOES) weather satellites. We confirm that in slow meteors, the radiation of the Planck continuum dominates, but for faster meteors, a correction on velocity is needed. We observe that the altitude where the oxygen line was recorded can also affect the radiation at 777 nm. In addition, determining whether or not the meteor showed a bright flare could also lead to a similar effect. Thus, the meteor brightness estimate may be impacted by these characteristics. We derived simple corrections on the altitude and on the meteor brightness that helped to improve the overall precision of the magnitude estimate of our sample. This allowed us to estimate the magnitude of meteors observed by GLM with an accuracy of ~ 1 in magnitude. The Na/Mg line intensity ratio was found to be constant for velocities above 25 km/s and increasing toward lower velocities.
