Study of auroral dynamics with combined spacecraft and incoherent scatter radar data

The objectives of this project were to study the coupling between the ionosphere and the magnetosphere, and to understand how this coupling was affected by changes in the solar wind. The data used consisted of satellite measurements coordinated with Sondrestrom incoherent scatter radar observations. We focused our efforts on the study of temporal and spatial changes in the dayside auroral precipitation and electric field

The dynamic cusp at low altitudes: A case study combining Viking, DMSP, and Sondrestrom incoherent scatter radar observations

A case study involving data from three satellites and a ground-based radar are presented. Focus is on a detailed discussion of observations of the dynamic cusp made on 24 Sep. 1986 in the dayside high-latitude ionosphere and interior magnetosphere. The relevant data from space-borne and ground-based sensors is presented. They include in-situ particle and field measurements from the DMSP-F7 and Viking spacecraft and Sondrestrom radar observations of the ionosphere. These data are augmented by observations of the IMF and the solar wind plasma. The observations are compared with predictions about the ionospheric response to the observed particle precipitation, obtained from an auroral model. It is shown that observations and model calculations fit well and provide a picture of the ionospheric footprint of the cusp in an invariant latitude versus local time frame. The combination of Viking, Sondrestrom radar, and IMP-8 data suggests that we observed an ionospheric signature of the dynamic cusp. Its spatial variation over time which appeared closely related to the southward component of the IMF was monitored

Geomagnetic variations and their time derivatives during geomagnetic storms at different levels of intensity

International audienceThe latitudinal distributions of horizontal geomagnetic variations, ΔH, and their time derivatives, ∂H/∂t, were analysed statistically over the three-year period 2003-2005. It appears that the amplitude distributions of horizontal geomagnetic variations and their time derivatives differ systematically between different geomagnetic latitudes and storm intensity levels. We show that the magnetic field variations observed at auroral and polar cap latitudes are under all geomagnetic storm levels comparable in amplitude (in a statistical sense) while they are smaller at subauroral latitudes. In contrast, their time derivatives are clearly the largest at auroral latitudes at all storm levels. These distributions determine in a general sense where and with which probability technological systems and operational procedures may be affected by geomagnetic storms. However, one observes in individual cases that the peak ∂H/∂t (the largest in all horizontal directions) is not necessarily the one which triggers a power system blackout

The Design of Value Added Services to Serve ESPAS Users

The primary objective of ESPAS is to support the access to observations from the near‐Earth space environment. This is a region that extends from the Eart's atmosphere up to the inner magnetosphere. Observing instruments that are linked to ESPAS include ionosondes, incoherent scatter radars, magnetometers, GNSS receivers and a large number of space sensors and radars. The ESPAS platform supports the systematic exploration of multi‐point measurements from near‐Earth space through homogeneous access to diverse data, enhances researchers' capability to develop advanced models of the geospace, supports data assimilation and provides tools for validation of models. Although the system development is in its early phase, the consortium has already started to analyse indicative scientific problems, whose study will be possible through the use of ESPAS services. The scientific advances resulting from these studies will lead to the development of validated scientific models and consequently to reliable predictions and related products and value‐added services that will meet the needs of scientists, operators, decision makers, system developers, etc. An important work done within the ESPAS project is the definition of several scientific scenarios called "use cases". The "use cases" express the user requirements on the ESPAS system, in other words they express "what" the system should be able to perform. These scenarios are exploring the required behaviour of ESPAS and form a solid basis for testing the system's behaviour as it responds to a request that originates from outside of the system. The following main groups of use cases are under analysis and first results will be reported in the ESWW10: a) Homogenised access to the main ESPAS data repositories b) coincidences and conjunctions between groundspace and space‐space monitoring units c) tools to validate models d) on line implementation of models able to support space weather prediction services