Instruments:eqb

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Estimated Midnight Equatorward Boundary of the Aurora

Contents 1 Estimated Midnight Equatorward Boundary of the Aurora 1.1 Contact Persons 1.2 Web Site 1.3 NOTES 1.4 ACKNOWLEDGMENTS 1.5 Data Description 1.6 References 1.7 Summary Plots for Estimated Midnight Equatorward Boundary of the Aurora

Contact Persons

• Susan Gussenhoven-Shea or Katharine Kadinsky-Cade or Frederick Rich

Web Site

• Data and Plots
• Recent plots

NOTES

• 01/28/03: All 1983-present data was replaced and replotted. A complete re-analysis was done by AFRL in 12/02. The average changes were: 17% fewer points in 1983-1991, 12% more points in 1992-1997, and 8% fewer points in 1998-2001. The maximum changes were 28% fewer points in 1989 and 26% more points in 1992. The values changed by only a few tenths of a degree.

ACKNOWLEDGMENTS

The Air Force Research Laboratory Auroral Boundary Index was provided by the USAF Research Laboratory, Hanscom AFB, MA via the CEDAR Database. (Please send a courtesy copy or reference to any publications using the boundary index to Dr. Fred Rich.)

Data Description

The Defense Meteorological Satellite Program (DMSP) has launched DMSP satellites since the mid 1970s. All the satellites have had precipitating particle spectrometer sensors (SSJ2-J4) on board. The SSJ4 sensor was first flown on DMSP-F6 in late 1982, so 1983 is the start of the automatically computed equivalent boundary data set. The official name of the index is "The Air Force Research Laboratory Auroral Boundary Index" and should be acknowledged as being provided by the USAF Research Laboratory, Hanscom AFB, MA. A courtesy copy of any publications using the index should also be sent to Dr. M. Susan Gussenhoven-Shea or her replacement, Dr. Katharine Kadinsky-Cade, at Air Force Research Laboratory, VSBXS, 29 Randolph Road, Hanscom Air Force Base, MA 01731-3010.

For most of the DMSP orbits on a given day, the auroral oval is crossed twice in each hemisphere, once on the ascending leg, and once on the descending leg. The auroral oval expands during increased auroral or magnetic activity and the equtorward boundary is strongly related to Kp (Gussenhoven et al., 1981). The poleward boundary is more difficult to detect than the equatorward boundary, so only the equatorward boundary is found automatically. Hand selection of the equatorward boundary is described in Gussenhoven et al. [1981, 1983]. The magnetic latitude of the equatorward boundary of the aurora is found for a particular orbit at a particular MLT. Then the magnetic latitude of the equivalent equatorward boundary at midnight magnetic local time (0 MLT) can be estimated by statistically determining the position of the auroral oval for every local time sector as a function of some magnetic activity index, such as Kp.

A computer algorithm was written to select the boundaries imitating the rules for hand selection with a quality flag of: 'best', 'good', 'not good'. Only those flagged as 'best' are released. Determination of the quality depends on a variety of factors. Generally,the clearest boundaries occur premidnight, that is, on the evening side, but not prior to 17 MLT. The next best are on the dawn side. Here, however, the flux levels are decreasing and the boundaries are not sharp. The worst boundaries are on the dayside, and near midnight when the oval is cut obliquely. Therefore, the preponderance of boundaries with the 'best' flag are on the evening side. Only 1/3 of the total are 'best' boundaries.

The equivalent equatorward boundary determined for 0 MLT is always defined positive, regardless of the hemisphere of the satellite. These data are also available as yearly files from the contact persons. The ftp and web sites at AFRL have been disconnected. Publically available plots from 1983 are available below.

References

Gussenhoven, M. S., D. A. Hardy and W. J. Burke, DMSP/F2 electron observations of equatorward auroral boundaries and their relationship to magnetospheric electric fields, J. Geophys. Res., 86, 768-778, 1981.

Gussenhoven, M. S., D. A. Hardy and N. Heinemann, Systematics of the equatorward diffuse auroral boundary, J. Geophys. Res., 88, 5692-5708, 1983.

Summary Plots for Estimated Midnight Equatorward Boundary of the Aurora

• Jan 01, 1983-Mar 01, 1983 All data for this period
• Mar 02, 1983-Apr 30, 1983 All data for this period
• May 01, 1983-Jun 29, 1983 All data for this period
• Jun 30, 1983-Aug 28, 1983 All data for this period
• Aug 29, 1983-Oct 27, 1983 All data for this period
• Oct 28, 1983-Dec 26, 1983 All data for this period
• Dec 27, 1983-Feb 24, 1984 All data for this period
• Feb 25, 1984-Apr 24, 1984 All data for this period
• Apr 25, 1984-Jun 23, 1984 All data for this period
• Jun 24, 1984-Aug 22, 1984 All data for this period
• Aug 23, 1984-Oct 21, 1984 All data for this period
• Oct 22, 1984-Dec 20, 1984 All data for this period
• Dec 21, 1984-Feb 18, 1985 All data for this period
• Feb 19, 1985-Apr 19, 1985 All data for this period
• Apr 20, 1985-Jun 18, 1985 All data for this period
• Jun 19, 1985-Aug 17, 1985 All data for this period
• Aug 18, 1985-Oct 16, 1985 All data for this period
• Oct 17, 1985-Dec 15, 1985 All data for this period
• Dec 16, 1985-Feb 13, 1986 All data for this period
• Feb 14, 1986-Apr 14, 1986 All data for this period
• Apr 15, 1986-Jun 13, 1986 All data for this period
• Jun 14, 1986-Aug 12, 1986 All data for this period
• Aug 13, 1986-Oct 11, 1986 All data for this period
• Oct 12, 1986-Dec 10, 1986 All data for this period
• Dec 11, 1986-Feb 08, 1987 All data for this period
• Feb 09, 1987-Apr 09, 1987 All data for this period
• Apr 10, 1987-Jun 08, 1987 All data for this period
• Jun 09, 1987-Aug 07, 1987 All data for this period
• Aug 08, 1987-Oct 06, 1987 All data for this period
• Oct 07, 1987-Dec 05, 1987 All data for this period
• Dec 06, 1987-Feb 03, 1988 All data for this period
• Feb 04, 1988-Apr 03, 1988 All data for this period
• Apr 04, 1988-Jun 02, 1988 All data for this period
• Jun 03, 1988-Aug 01, 1988 All data for this period
• Aug 02, 1988-Sep 30, 1988 All data for this period
• Oct 01, 1988-Nov 29, 1988 All data for this period
• Nov 30, 1988-Jan 28, 1989 All data for this period
• Jan 29, 1989-Mar 29, 1989 All data for this period
• Mar 30, 1989-May 28, 1989 All data for this period
• May 29, 1989-Jul 27, 1989 All data for this period
• Jul 28, 1989-Sep 25, 1989 All data for this period
• Sep 26, 1989-Nov 24, 1989 All data for this period
• Nov 25, 1989-Jan 23, 1990 All data for this period
• Jan 24, 1990-Mar 24, 1990 All data for this period
• Mar 25, 1990-May 23, 1990 All data for this period
• May 24, 1990-Jul 22, 1990 All data for this period
• Jul 23, 1990-Sep 20, 1990 All data for this period
• Sep 21, 1990-Nov 19, 1990 All data for this period
• Nov 20, 1990-Jan 18, 1991 All data for this period
• Jan 19, 1991-Mar 19, 1991 All data for this period
• Mar 20, 1991-May 18, 1991 All data for this period
• May 19, 1991-Jul 17, 1991 All data for this period
• Jul 18, 1991-Sep 15, 1991 All data for this period
• Sep 16, 1991-Nov 14, 1991 All data for this period
• Nov 15, 1991-Jan 13, 1992 All data for this period
• Jan 14, 1992-Mar 13, 1992 All data for this period
• Mar 14, 1992-May 12, 1992 All data for this period
• May 13, 1992-Jul 11, 1992 All data for this period
• Jul 12, 1992-Sep 09, 1992 All data for this period
• Sep 10, 1992-Nov 08, 1992 All data for this period
• Nov 09, 1992-Jan 07, 1993 All data for this period
• Jan 08, 1993-Mar 08, 1993 All data for this period
• Mar 09, 1993-May 07, 1993 All data for this period
• May 08, 1993-Jul 06, 1993 All data for this period
• Jul 07, 1993-Sep 04, 1993 All data for this period
• Sep 05, 1993-Nov 03, 1993 All data for this period
• Nov 04, 1993-Jan 02, 1994 All data for this period
• Jan 03, 1994-Mar 03, 1994 All data for this period
• Mar 04, 1994-May 02, 1994 All data for this period
• May 03, 1994-Jul 01, 1994 All data for this period
• Jul 02, 1994-Aug 30, 1994 All data for this period
• Aug 31, 1994-Oct 29, 1994 All data for this period
• Oct 30, 1994-Dec 28, 1994 All data for this period
• Dec 29, 1994-Feb 26, 1995 All data for this period
• Feb 27, 1995-Apr 27, 1995 All data for this period
• Apr 28, 1995-Jun 26, 1995 All data for this period
• Jun 27, 1995-Aug 25, 1995 All data for this period
• Aug 26, 1995-Oct 24, 1995 All data for this period
• Oct 25, 1995-Dec 23, 1995 All data for this period
• Dec 24, 1995-Feb 21, 1996 All data for this period
• Feb 22, 1996-Apr 21, 1996 All data for this period
• Apr 22, 1996-Jun 20, 1996 All data for this period
• Jun 21, 1996-Aug 19, 1996 All data for this period
• Aug 20, 1996-Oct 18, 1996 All data for this period
• Oct 19, 1996-Dec 17, 1996 All data for this period
• Dec 18, 1996-Feb 15, 1997 All data for this period
• Feb 16, 1997-Apr 16, 1997 All data for this period
• Apr 17, 1997-Jun 15, 1997 All data for this period
• Jun 16, 1997-Aug 14, 1997 All data for this period
• Aug 15, 1997-Oct 13, 1997 All data for this period
• Oct 14, 1997-Dec 12, 1997 All data for this period
• Dec 13, 1997-Feb 10, 1998 All data for this period
• Feb 11, 1998-Apr 11, 1998 All data for this period
• Apr 12, 1998-Jun 10, 1998 All data for this period
• Jun 11, 1998-Aug 09, 1998 All data for this period
• Aug 10, 1998-Oct 08, 1998 All data for this period
• Oct 09, 1998-Dec 07, 1998 All data for this period
• Dec 08, 1998-Feb 05, 1999 All data for this period
• Feb 06, 1999-Apr 06, 1999 All data for this period
• Apr 07, 1999-Jun 05, 1999 All data for this period
• Jun 06, 1999-Aug 04, 1999 All data for this period
• Aug 05, 1999-Oct 03, 1999 All data for this period
• Oct 04, 1999-Dec 02, 1999 All data for this period
• Dec 03, 1999-Jan 31, 2000 All data for this period
• Feb 01, 2000-Mar 31, 2000 All data for this period
• Apr 01, 2000-May 30, 2000 All data for this period
• May 31, 2000-Jul 29, 2000 All data for this period
• Jul 30, 2000-Sep 27, 2000 All data for this period
• Sep 28, 2000-Nov 26, 2000 All data for this period
• Nov 27, 2000-Jan 25, 2001 All data for this period
• Jan 26, 2001-Mar 26, 2001 All data for this period
• Mar 27, 2001-May 25, 2001 All data for this period
• May 26, 2001-Jul 24, 2001 All data for this period
• Jul 25, 2001-Sep 22, 2001 All data for this period
• Sep 23, 2001-Nov 21, 2001 All data for this period
• Nov 22, 2001-Jan 20, 2002 All data for this period
• Jan 21, 2002-Mar 21, 2002 All data for this period
• Mar 22, 2002-May 20, 2002 All data for this period
• May 21, 2002-Jul 19, 2002 All data for this period
• Jul 20, 2002-Sep 17, 2002 All data for this period
• Sep 18, 2002-Nov 16, 2002 All data for this period
• Nov 17, 2002-Jan 15, 2003 All data for this period
• Jan 16, 2003-Mar 16, 2003 All data for this period
• Mar 17, 2003-May 15, 2003 All data for this period
• May 16, 2003-Jul 14, 2003 All data for this period
• Jul 15, 2003-Sep 12, 2003 All data for this period
• Sep 13, 2003-Nov 11, 2003 All data for this period
• Nov 12, 2003-Jan 10, 2004 All data for this period
• Jan 11, 2004-Mar 10, 2004 All data for this period
• Mar 11, 2004-May 09, 2004 All data for this period
• May 10, 2004-Jul 08, 2004 All data for this period
• Jul 09, 2004-Sep 06, 2004 All data for this period
• Sep 07, 2004-Nov 05, 2004 All data for this period
• Nov 06, 2004-Jan 04, 2005 All data for this period
• Jan 05, 2005-Mar 05, 2005 All data for this period
• Mar 06, 2005-May 04, 2005 All data for this period
• May 05, 2005-Jul 03, 2005 All data for this period
• Jul 04, 2005-Sep 01, 2005 All data for this period
• Sep 02, 2005-Oct 31, 2005 All data for this period
• Nov 01, 2005-Dec 30, 2005 All data for this period
• Dec 31, 2005-Feb 28, 2006 All data for this period

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-Revised 01 Feb 2006 by Barbara Emery