A new Algorithm for Rapid Magnetospheric Field Modelling using Swarm Data
Hamilton, Brian
British Geological Survey, UNITED KINGDOM

We present an algorithm for per orbit modelling of the Earth's large scale vector magnetospheric field using satellite data, with potential for near to real time use. The method has been implemented as part of the "Satellite Constellation Application and Research Facility" (SCARF) for the ESA Swarm mission, making use of the unprecedented spatial coverage the constellation will offer. The magnetospheric model will be released daily as part of the Level-2 data product range. As well as addressing scientific interests in the external field of the Earth, the vector magnetospheric model will be of use in space weather applications where measures of geomagnetic activity are required, and as inputs to other magnetic field modelling studies. Unlike magnetospheric indices, such as the 'scalar-valued' Disturbance Storm Time (Dst) index, the algorithm presented here attempts to preserve the absolute level of the field by avoiding post-fitting a baseline and instead takes as input the residuals after removing a priori models of the non-magnetospheric fields. The algorithm is robust, operates automatically, and has the potential to be run in near real-time if required. We present test models produced using CHAMP and Oersted satellite data, and validated against the Dst and Vector Magnetic Disturbance (VMD) indices. We also test the algorithm's ability to recover a 'true' magnetospheric field, by using the synthetic comprehensive Swarm Level 2 Processing System's Test Data Set (TDS-1) as input. It is possible that early validation results with magnetic data from the Swarm mission will be presented if launch is successful in the preceding months.