The STEP 210° Magnetic Meridian Network Project

Abstract

Imaging the Earth's magnetosphere by using ground-based magnetometer arrays is still one of the major techniques for investigating the dynamical features of solar wind-magnetosphere interactions. The organized ground network data of magnetic fields make it possible (1) to study the magnetospheric processes by distinguishing between temporal changes and spatial variations in the phenomena, (2) to clarify the global latitudinal structures and propagation characteristics of magnetic variations from high to equatorial latitudes along the magnetic meridian (MM), and (3) to understand the global generation mechanism of magnetospheric phenomena. During the international Solar Terrestrial Energy Program (STEP) period of 1990-1997, multinationally coordinated magnetic observations are being conducted along the 190°, 210°, and 250° MMs from high latitudes through middle and low latitudes to the equatorial region, spanning L = 8.50-1.00, in cooperation with 29 organizations in Australia, Indonesia, Japan, Papua New Guinea, Philippines, Russia, Taiwan, and the United States. In this paper, we review the 210° MM Magnetic Observation Project and its initial results.