Gravity Wave and Seismic Signatures in the Airglow

夜间的气辉来自于80 - 100公里高度的上层大气。在这一层中，涉及到氧原子重组的化学反应产生的光可以被地面上的仪器探测到。大气中的各种动态过程会导致夜间气辉发射亮度的波动。我们用地面仪器测量这些波动，并利用它们来推断导致波动的过程的性质。本文将研究这些动力学过程中的两个过程。首先，我们将研究重力波的影响。这些波是在大气区域之间传递能量和动量的主要机制。了解它们的性质和发生频率对发展包括数值天气预报模式在内的大气模式很重要。其次，我们将研究在我们观察到的气辉模式中可以检测到地震活动产生的次声波的可能性。令人非常感兴趣的是，在地震发生之前可以看到气辉变化的可能性。这种行为过去曾有过报道，但尚未得到令人信服的证实。我们所研究的变化的性质可能会根据当地的因素而有很大的不同，比如在山脉等地表特征上吹过的风，以及雷暴等活跃的天气模式。因此，我们将仪器放置在世界各地相隔很远的地方，以便在各种地方进行观察。目前，我们在南极洲和挪威的北极圈内都有仪器。2006年，我们将在印度地震活动频繁的山区安装第三台仪器。

The night airglow comes from a layer in the upper atmosphere at a height of 80 - 100 km.  In this layer, chemical reactions involving the recombination of oxygen atoms lead to the emission of light that can be detected by instruments on the ground. Various dynamical processes in the atmosphere can lead to fluctuations in the brightness of the night airglow emissions.  We measure these fluctuations with ground-based instruments and use them to infer the nature of the processes that cause them.   Two processes of these dynamical processes will be studied in the present work.  Firstly, we will study the effects of gravity waves.  These waves are a major mechanism for transporting energy and momentum between atmospheric regions.  Understanding their nature and frequency of occurrance is important in the development of atmospheric models including numerical weather prediction models.  Secondly, we will examine the possibility that infrasonic waves generated by seismic activity can be detected in the airglow patterns we observe.  Of great interest is the possibility that airglow variations can be seen before the occurrance of the earthquake.  Such behaviour has been reported in the past but has not been convincingly verified. The nature of the variations that we study can vary greatly according to local factors such winds blowing over surface features such as mountain ranges as well as active weather patterns such as thunderstorms. As a result, we locate our instruments at widely separated locations around the world to observe in a variety of locales. Currently we have instruments both in Antarctica and within the Arctic circle in Norway.  In 2006, we will install a third instrument at a mountain site in India in a region of frequent seismic activity.