Space Weather Effects on the Upper Atmosphere

Datum 21.04.2021
Zeit16:15 Uhr
OrtOnline
Zoom Link
Meeting-ID: 686 3517 6749
Referent Dr. Eelco Doornbos (RNMI)
Abstract

Among the earliest scientific results of the space age were measurements of upper atmospheric density, obtained by tracking the orbital decay of the first artificial satellites. These data soon resulted in the discovery of the strong correlation between upper atmospheric density and solar and geomagnetic activity. We now understand that the atmosphere above about 100 km is largely driven by absorption of solar EUV and X-ray radiation on the sunlit side of the Earth. Charged particles trapped in Earth's magnetic field continuously deposit additional energy in the auroral zones at high latitudes. This additional source of energy can become the dominant one during geomagnetic storms, when the Earth's magnetosphere gets efficiently connected to and is rattled by the solar wind. Such space weather storms, which can last up to a few days, cause a rapid expansion of the upper atmosphere globally, sometimes increasing satellite drag by up to an order of magnitude.
Our knowledge of the upper atmospheric is still advancing, through progress made in remote sensing techniques, but also by more precise methods to measure and analyse the motion of satellites. Modern data has revealed that coupling between the lower and upper atmosphere through waves and tides also plays a very important role in upper atmospheric dynamics. This realization has led to the development of whole atmosphere models, extending from the ground up to hundreds of kms in altitude. This talk will provide an overview of the past, present and future of the measurements and science of the neutral upper atmosphere.