DMSP:ssj4 midnit

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DMSP SSJ4 Midnight Boundary Index Obtained from Precipitating Electrons

Contents 1 DMSP SSJ4 Midnight Boundary Index Obtained from Precipitating Electrons 1.1 DATA FILES 1.2 PLOTS 1.3 CONCEPT 1.4 REFERENCES 1.5 Last Updated

DATA FILES

Please read the "Rules of the Road" notice before using any of these data.

The Midnight Boundary Index is an estimate of the equatorward boundary of precipitating auroral electrons as determined by the SSJ/4 (F06 through F15) and SSJ/5 (F16 and beyond) instruments on DMSP spacecraft. Midnight Boundary data are available in the CEDAR Database and also in yearly ascii files below.

In March 2009, all the files were replace to add additional information. Previously, only the year, daynumber, UTsec, and estimated midnight equatorward boundary in magnetic latitude were given. The additional information is the satellite ID (F06=7540, F07=8541, F08=9543, F09=0542, F10=1544, F11=2546, F12=3545, F13=4547, F14=5548, F15=6549, F16=7454, F17=8550), where the ten's place digit indicates '4' or '5' for SSJ/4 or SSJ/5. Extra parameters are the geographic latitude times 10 and the magnetic local time (MLT) in seconds of the equatorward boundary crossing which is then estimated at the midnight MLT.

• 1983
• 1984
• 1985
• 1986
• 1987
• 1988
• 1989
• 1990
• 1991
• 1992
• 1993
• 1994
• 1995
• 1996
• 1997
• 1998
• 1999
• 2000
• 2001
• 2002
• 2003
• 2004
• 2005
• 2006
• 2007
• 2008
• 2009

Midnight Boundary data are also available from AFRL upon request. If the data are used in scientific studies, they should be referred to as "The Air Force Research Laboratory Auroral Boundary Index" and acknowledged as being provided by the USAF Research Laboratory, Hanscom AFB, MA. These data are in the public domain and no further permission is required. Please send a courtesy copy of any publications using the Boundary Index to Dr. K. Kadinsky-Cade

PLOTS

This x-y plot shows Midnight Boundary variations during a 27 day period.

To see plots of recent values of the midnight boundary index, click on the items below. Files of the values plotted here and older values along with a "readme" file describing the files are available upon request.

• 01 Jan 1994 to 20 Mar 1994
• 21 Mar 1994 to 09 Jun 1994
• 10 Jun 1994 to 29 Aug 1994
• 20 Aug 1994 to 18 Nov 1994
• 19 Nov 1994 to 07 Feb 1995
• 08 Feb 1995 to 29 Apr 1995
• 30 Apr 1995 to 19 Jul 1995
• 20 Jul 1995 to 08 Oct 1995
• 09 Oct 1995 to 28 Dec 1995
• 29 Dec 1995 to 18 Mar 1996
• 19 Mar 1996 to 07 Jun 1996
• 08 Jun 1996 to 27 Aug 1996
• 28 Aug 1996 to 16 Nov 1996
• 17 Nov 1996 to 05 Feb 1997
• 06 Feb 1997 to 27 Apr 1997
• 28 Apr 1997 to 17 Jul 1997
• 18 Jul 1997 to 06 Oct 1997
• 07 Oct 1997 to 26 Dec 1997
• 27 Dec 1997 to 17 Mar 1998
• 18 Mar 1998 to 06 Jun 1998
• 07 Jun 1998 to 26 Aug 1998
• 27 Aug 1998 to 15 Nov 1998
• 16 Nov 1998 to 04 Feb 1999
• 05 Feb 1999 to 26 Apr 1999
• 27 Apr 1999 to 16 Jul 1999
• 17 Jul 1999 to 05 Oct 1999
• 06 Oct 1999 to 25 Dec 1999
• 26 Dec 1999 to 15 Mar 2000
• 16 Mar 2000 to 04 Jun 2000
• 05 Jun 2000 to 24 Aug 2000
• 25 Aug 2000 to 13 Nov 2000
• 14 Nov 2000 to 02 Feb 2001
• 03 Feb 2001 to 24 Apr 2001
• 25 Apr 2001 to 14 Jul 2001
• 15 Jul 2001 to 03 Oct 2001
• 04 Oct 2001 to 23 Dec 2001
• 24 Dec 2001 to 14 Mar 2002
• 15 Mar 2002 to 03 Jun 2002
• 04 Jun 2002 to 23 Aug 2002
• 24 Aug 2002 to 12 Nov 2002
• 13 Nov 2002 to 1 Feb 2003
• 2 Feb 2003 to 23 Apr 2003
• 24 Apr 2003 to 13 Jul 2003
• 14 Jul 2003 to 02 Oct 2003
• 03 Oct 2003 to 22 Dec 2003
• 23 Dec 2003 to 12 Mar 2004
• 13 Mar 2004 to 01 Jun 2004
• 02 Jun 2004 to 21 Aug 2004
• 22 Aug 2004 to 10 Nov 2004
• 11 Nov 2004 to 31 Jan 2005
• 01 Feb 2005 to 22 Apr 2005
• 23 Apr 2005 to 12 Jul 2005
• 13 Jul 2005 to 01 Oct 2005
• 02 Oct 2005 to 21 Dec 2005
• 22 Dec 2005 to 11 Mar 2006

Written by Frederick Rich. Point of Contact: Dr. Gordon Wilson

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CONCEPT

It has long been known that increased auroral activity, as indicated by many ionospheric and magnetospheric parameters such as brightness of auroral arcs, disturbances in the magnetic field, magnitude of the convection electric field and magnitude of field aligned currents, is accompanied by the expansion of the auroral oval.

A statistical study of the electron precipitation observed by SSJ4 instruments on DMSP spacecraft to Kp values was done by Gussenhoven et al. (1981). They determined the regression coefficients for a linear fit of equatorward auroral boundaries for 13 of the 24 hourly local time sectors and compared the results to the Kp indices. They identified equatorward auroral boundaries by hand, using precipitating electron measurements made onboard the DMSP/F2 satellite. A follow-on study (Gussenhoven et al., 1983) developed a computer algorithm for boundary selection and increased the database to 20 of 24 local time sectors by including data from DMSP F4. This work has continued to date with all available data from the SSJ4 instruments flown on DMSP spacecraft.

Although the auroral equatorward boundary, when drawn in geomagnetic coordinates, is nearly circular for all levels of auroral activity, its center is offset from the magnetic pole toward the post-midnight local time sector. The offset is a function of magnetic activity. Therefore, individual boundary measurements made for the same auroral activity, but at different local times will differ, and, as such, cannot be directly scaled to auroral activity without removing the local time variation. Removal of the local time variation is reasonably easy to accomplish 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.

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, 1981.
• Gussenhoven, M.S., D.A. Hardy, N. Heinemann, and E. Holeman, 1978 Diffuse Auroral Boundaries and a Derived Auroral Boundary Index, AFGL-TR-82-0398, Air Force Geophysics Laboratory, Hanscom AFB, MA, (ADA130175), 1982.
• Gussenhoven, M.S., D.A. Hardy, and N. Heinemann, Systematics of the equatorward diffuse auroral boundary, J. Geophys. Res., 88, A7, 5692-5708, 1983.
• Hardy, D. A., and M. S. Gussenhoven, A Statistical Model of Auroral Electron Precipitation, J. Geophys. Res., 90, A5, 4229-4248, 1985.
• Schumaker, T.L., D.A. Hardy, S. Moran, A. Huber, J. McGarity, and J. Pantazis, Precipitating lon and Electron Detectors SSJ/4) for the Block 5D/Flight 8 DMSP Satellite, AFGL-TR-884030, Air Force Geophysics Laboratory, Hanscom AFB, MA, (ADA203990) 1988.
• Madden, D., and M. S. Gussenhoven, Auroral Boundary Index from 1983 to 1990, Tech Report GL-TR-90-0358, Air Force Geophysics Laboratory, Hanscom AFB, MA, 21 Dec. 1990.

Last Updated

Last Update of Page Format: 16 May 2006 by Frederick Rich. Point of Contact: Gordon Wilson

Last Update: 06 Mar 2009 by Barbara Emery