Sarah Reay

Surface electric fields and geomagnetically induced currents in the Scottish Power grid during the 30 October 2003 geomagnetic storm

A surface electric field model is used to estimate the UK surface E field during the 30 October 2003 severe geomagnetic storm. This model is coupled with a power grid model to determine the flow of geomagnetically induced currents (GIC) through the Scottish part of the UK grid. Model data are compared with GIC measurements at four sites in the power network. During this storm, measured and modeled GIC levels exceeded 40 A, and the surface electric field reached 5 V/km at sites in the United Kingdom (compared with quiet-time levels of less than 0.1 V/km). The electric field and grid models now form part of a GIC monitoring, analysis, and warning software package with Web interface, developed for use by the grid operator. This package also contains a daily geomagnetic activity forecast service, a solar wind shock detector for geomagnetic storm warning, and a near-real-time geomagnetic data stream for storm monitoring.

A method for the near real-time production of quasi-definitive magnetic observatory data

Magnetic observatory data are widely used in the derivation of time-varying magnetic field models, often in combination with satellite magnetic data, when available. Traditionally the definitive observatory results are used, the availability of which can often lag those of the satellite data by months and even years. The recently defined quasi-definitive observatory data type has been introduced to meet the need to provide observatory data suitable for use in field modeling in a more rapid time frame and for producing Level 2 products planned for the upcoming European Space Agency Swarm mission. A method for producing quasi-definitive data is presented and the essential steps described. To evaluate the method, provisional data published on a next day basis since 2000 are tested against definitive data at five INTERMAGNET observatories. The means and standard deviations of the differences between the candidate quasi-definitive and definitive data are within the accuracy of 5 nT set by INTERMAGNET. Since the tested data were published on-line on a next day basis, they also easily meet the INTERMAGNET requirement of availability within three months. These results demonstrate that prompt production of quasi-definitive data is possible for observatories that already perform to the standards set by INTERMAGNET.

Magnetic Observatory Data and Metadata: Types and Availability

The availability of magnetic observatory data has evolved rapidly with the transition of observatories from analogue photographic magnetograms to digital electronic recordings, and the advent of the internet for instant global access to information of every sort. Metadata (information about the data) is undergoing its own transformation in order to accompany the rapid and extensive dissemination of these data. This chapter describes the types of data historically and currently produced by geomagnetic observatories and introduces new data types such as one-second and quasi-absolute data recently discussed at the 11th IAGA Scientific Assembly in Sopron, Hungary. We review the availability of these data types from the World Data Centres, INTERMAGNET and other sources. Finally, we discuss developments in metadata describing the current efforts in the geomagnetism community to gather, store and distribute this information about the data to better assist scientific discovery.