DATA ASSIMILATION FOR THE STUDY OF MAGNETOSPHERE-IONOSPHERE-ATMOSPHERE COUPLING

最先进的电离层成像技术使用全球定位系统（GPS）卫星数据。在医学成像中，病人是通过x射线检查的，与此类似，在电离层成像中，上层大气（电离层）是通过无线电波检查的。电离层成像的下一个重要步骤是将其与电离层模型结合起来。这样做的原因是为了发现潜在的物理原理，我们不能仅仅通过看图像来做得很好。我们需要将这些图像与风、太阳辐射和电场的模型联系起来，以便了解是什么导致了高层大气环境在极端事件（称为风暴）期间的行为。这些不是我们所熟悉的天气风暴，而是由来自太阳的粒子和辐射轰击大气层的外层造成的空间天气风暴。我们需要将测量结果与模型联系起来的数学称为数据同化。数据同化在气象学中已经取得了惊人的成功。在这项资助下发展的数据同化是用于更高的大气（100公里以上），并将用于研究中性大气和电离大气之间的耦合，并确定电离层-大气动力学和磁层动力学之间的关系。

State-of-the-art ionospheric imaging techniques use Global Positioning System (GPS) satellite data. In a similar manner to medical imaging, where the patient is examined by X-rays, in ionospheric imaging the upper atmosphere (ionosphere) is examined by radio waves. The next big step for ionospheric imaging is to combine it with models of the ionosphere. The reason to do this is to discover the underlying physics, which we cannot do very well by just looking at the images. We need to link the images to models of winds, solar radiation and electric fields in order to understand what causes the upper atmospheric environment to behave as it does during extreme events called storms. These are not the weather storms we are familiar with but rather these space-weather storms are caused by the bombardment of the outer realms of the atmosphere with particles and radiation from the Sun. The mathematics we need to link the measurements to the models is called data assimilation. Data assimilation has already been strikingly successful in meteorology. The data assimilation to be developed under this grant is for much higher up in the atmosphere (above 100 km) and will be used to investigate the coupling between the neutral and ionized atmosphere and to determine the relationships between ionosphere-atmosphere dynamics and magnetosphere dynamics.