*************************** ** THE GEM MESSENGER ** *************************** Volume 5, Number 10 March 24, 1995 ---------------------------------------------------------------------- CEDAR/GEM/SUNRISE Space Weather Project (and a Possible National Space Weather-GEM Study Event) ----------------------------------------------------------------------- From: W. Jeff Hughes (HUGHES at buasta.bu.edu) At the GEM Steering Committee Meeting held during the December AGU (which was also attended by Jeff Forbes in his ex-officio capacity as Chairman of the CEDAR Science Steering Committee, and by all the NSF Upper Atmosphere Section program directors) it was decided, given the new initiative in "space weather" and indeed in the interest of good science, that we ought to examine one or more major solar-terrestrial interaction events as a combined community (encompassing CEDAR/aeronomy, GEM/magnetosphere, and SUNRISE/solar), tracing the event from the sun, through the solar wind and magnetosphere, and into the thermosphere/ionosphere system. We thought the best approach would be a series of joint workshops and AGU sessions, and that coordination of these activities should be accomplished through a steering commitee. An interdisciplinary committee, chaired by Dr. Delores Knipp was formed: M. Buonsanto (ionosphere/thermosphere) D. Knipp (ionosphere/magnetosphere/AMIE) L. Weiss (solar wind) J. Hughes (GEM liaison) J. Forbes (CEDAR liaison) The first charge of this committee was to choose a few solar-terrestrial events that meet the various diverse needs of the scientific groups. The group has come up with one such event, their description of which follows. Jeffrey Hughes and Jeffrey Forbes A POSSIBLE NATIONAL SPACE WEATHER-GEM STUDY EVENT The GEM community has a unique and challenging opportunity to become immediately involved in the National Space Weather Initiative. A solar wind event on 3-4 Nov 1993 appears to offer the possibility for multi-instrument study of its effects throughout the ionosphere and magnetosphere. The event already has the interest of the CEDAR Storm study group. Here is preliminary information on the event and its effects: Basic Event Description: There is evidence of 27 day recurring high speed stream activity. Solar imagery shows evidence of a CME late on 31 Oct 93 which may also play a role in the event. The shock associated with the event impacted the magnetosphere early on 3 Nov 1993. A high density feature within the stream caused major ionospheric and magnetospheric response shortly after 2300 UT on 3 Nov 93. A Storm Sudden Commencement has been identified in the World Data Center event listing. Shortly after 2300 UT on 3 Nov 93 sudden increases in solar wind velocity and density were recorded at IMP-8. The Ap maximum for the event was 78 and the DST minimum was -105. Preliminary Geophysical Results: DMSP ion drift data clearly show the convection enhancement associated with the event. The SAMPEX magnetospheric satellite indicated flux dropouts at L > 4 accompanied by energetic particle population enhancements at or near L=2. The Millstone Hill Radar saw the ionosphere's F region lift at L < 4 by nearly 100 km for a short time. Possible Data Sources to Support This Study: On a preliminary basis we know that IMP-8, SAMPEX and GEOTAIL have some supporting data. Three DMSP satellites with orbits near 840 km have ion drift meter and retarding potential analyzer data (and are likely to have particle data). Millstone Hill Radar was taking data (although this was not a designated World Day). Three Ionospheric Tomography chains were also operating during the event. The NOAA-12 and FREJA satellites were operating (data quality and availability are to be determined). GOES Geo-Synchronous data are available. Data from Los Alamos National Lab Geosynchronous satellites are available. Some optical data were taken at very high latitudes. Solar data include: YOKOH imagery, solar chronographs, H-alpha images, white light images, and radio heliographs. We are looking for ways to make this a truly large-scale study event, possibly modeling all the way from the Sun down to the thermosphere and thereby involving the solar and CEDAR communities as well. We are considering holding an initial informal workshop on the Wednesday during the GEM Snowmass Workshop to examine this event from a GEM perspective. The goals would be to explore what other observations are available and to assess the usefulness of this event as an example or test case for magnetospheric modeling. If you wish to be a participant in this study in terms of data provision or modeling please contact either Delores Knipp at knipp at ncar.ucar.edu or the CEDAR Storm Study Representative: Michael Buonsanto at mjb at oceanus.haystack.edu. +-------------------------------------------------------------------------+ |To add name to the mailing list, send a message to: editor at igpp.ucla.edu | |For message to whole GEM mailing list, send to: gem at igpp.ucla.edu | |For message to a specific working group (BL Campaign), send to: | | gem_field at igpp.ucla.edu (WG1); gem_boundary at igpp.ucla.edu (WG2); | | gem_current at igpp.ucla.edu (WG3); gem_data at igpp.ucla.edu (WG4) | | gem_ggcm at igpp.ucla.edu (WG5) | | gem_chair at igpp.ucla.edu (WG chairs, Odile and W. J. 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