New substorm index derived from high-resolution geomagnetic field data at low latitude and its comparison with AE and ASY indices

1 Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University, Japan 2 Kakioka Magnetic Observatory, Japan Meteorological Agency, Japan 3 Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico 4 Remote Sensing and Geomagnetism, Danish Meteorological Institute, Denmark 5 United States Geological Survey, United States 6 Geophysical Observatory, Department of Earth and Environmental Sciences, Ludwig-Maximilians University, Germany 7 Geomagnetism Laboratory, Kandilli Campus, Bogazici University, Turkey 8 Observatori de L'Ebre, CSIC Universitat Ramon Llull, Spain