Introduction

SuperMAG is a worldwide collaboration of ground based magnetometers generously supported by the National Science Foundation and NASA. It currently includes data from more than 200 stations generously provided by a long list of organizations and national agencies.

SuperMAG utilizes 3D vector measurements of the magnetic field obtained from ground bases magnetometers. Stations providing absolute measurements (e.g. Intermagnet Observatories) as well as stations providing relative measurements are included. SuperMAG is focused on the variations caused by electric currents flowing in the ionosphere and magnetosphere and hence subtracts the dominant and slowly varying Earth main field. SuperMAG does not enable the user to study the absolute magnetic field and hence could be referred to as a variometer initiative.

Motivation

For decades ground based magnetometers have proven to be the workhorse of magnetosphere-ionosphere physics and their importance is indisputable.

SuperMAG is the next logical step for the ground magnetometer community to take in the development of a user friendly data service enabling an understanding as well as monitoring of the global electric current system. The data set provided by the ground magnetometer community is truly unique since it provides a nearly global and continuous measurement of a fundamental parameter - the ground level magnetic field perturbations.

The purpose of the SuperMAG initiative is to provide a user-friendly web based interface to measured ground magnetic field perturbations in the same coordinate system, identical time resolution and with a common baseline removal approach. Global studies utilizing observations from all available observatories are inhibited or even prevented by several complications:
   1) Obtaining data;
   2) Removal of the main field (baseline determination);
   3) Unknown coordinate system used for the observations;
   4) Artifacts and errors.
SuperMag is developed to remove these obstacles for the user.

Obtaining Data

The SuperMAG family consists of a long list of collaborators
who generously have agreed to participate in the initiative. Data
are provided in a variety of file formats, temporal resolutions,
units, coordinate systems and are provided with or without
baseline subtracted. The original data can be obtained from the
websites listed on the cover page:
(http://supermag.jhuapl.edu/index.html).
SuperMAG resamples data provided with a higher than 1-min
temporal resolution and all data are converted to units of nT.

SuperMAG Data Handling

SuperMAG is managing a staggering >800,000 files. The
vast amount of data required SuperMAG to develop a simple
and robust data flow which could accommodate the various
types of data as well as their inherent complications. The
flow-chart illustrate the basic data flow from data provided
by the source to data released to the SuperMAG website.

Housekeeping plots are produced at each step and a number
of validation routines check the quality of the data output at
each step.