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Space Weather





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On 30 March 2001 in the late evening an auroral display was observed over the United States of America. The Bear Lake Observatory (BLO) magnetometer in Utah measured changes of 550 nT in less than 30 min. During the same period, BLO ionosonde measurements showed deep high-frequency radio wave absorption up to 7 MHz. BLO's GPS single-frequency receiver experienced geolocation errors of 20 m for over 3 hours. These storm signatures were also accompanied by L-band scintillation effects which approached an S4 value of 0.2, which is large for midlatitudes. Although such measurements have been have been made at midlatitude locations for many decades, our knowledge of the processes and couplings involved in such events remains incomplete and, at best, qualitative. The interpretation of key ionospheric parameters' storm response is discussed in the context of present-day auroral and geospace electrodynamics understanding. We find that at BLO (L = 2.38) the available data raise more questions and can provide almost no answers without observational inputs from other locations. One solution to this impasse is to field a ground-based sensor network to resolve the spatial scales of the geospace electrodynamics. On the basis of the instrument complement at BLO, we argue for a contiguous U.S. deployment of modest magnetic/optical/RF observatories to observe the next solar maximum period's geomagnetic storms and to use these data to explore the physical processes and couplings on space weather effective scales in assimilative models in conjunction with space-based observations.


Published by the American Geophysical Union in Space Weather.

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