Working Group V-MOD: Geomagnetic Field Modelling
    IUGG > IAGA > Division V > Working Group V-MOD > Minutes > Birmingham (1999)

Birgmingham - 1999 Minutes

 Thursday, July 22, 1999

Charlie Barton, the outgoing chairman, called the meeting to order at 19:00. Barton announced elections of new officers as both he and Vadim Golovkov were stepping down from the positions of Chair and Co-chair. The Chair reiterated the National Geophysical Data Center's survey of IGRF users and emphasized that users wanted an early adoption of an IGRF. The Chair also reported on a fast MS-Windows based IGRF program developed by Phil McFadden. Working group members were encouraged to use this freeware program.

After a brief presentation of the IGRF model candidates (main field and SV) for 2000, the models were summarized by Frank Lowes. Lowes observed that all models were essentially updates of DGRF 1980 with minimal new main field data.

A motion to adopt a secular variation model for the 2000-2005 epoch based on equal shares of the UK, IPGP, and Izmiran models was made by Frank Lowes. The motion was seconded by Purucker and passed with 14 in favor and none against.

B. Langlais of IPGP presented a global evaluation of the difference between a tentative Oersted model and the candidate main field models. The tentative Oersted model was based on Scalar Overhauser data constrained by a magnetic equator updated from IGRF95 with SV95. Differences up to 600 nT are found between the Oersted model and the candidate main field models.

In the ensuing discussion several working group members commented on the status of Oersted data and the prospects for making a main field model using the data. The prospects seem good that within a few months, high-quality Oersted vector data will be available from times of low magnetic activity. Frank Lowes emphasized to the Oersted modelers the importance of documenting their work as they go along. He also emphasized the importance of using data besides Oersted.

Charlie Barton made a motion to appoint a task force. The task force would be assigned the task of preparing a better IGRF model using the Oersted data. If the task force decides that it can not make a better model, or if it can not decide on a model, the working group will do the best it can with the previously presented models. The task force must publish the coefficients before Jan. 1, 2000. The motion was passed nem con.

Members of the task force were then suggested. The list of suggested individuals included Frank Lowes, Terry Sabaka, Nils Olsen, Mioara Mandea, J. Cain, S. MacMillan, V. Golovkov, and J. Quinn. After some discussion about the large size of this task force the list was winnowed to the following:

  1. Frank Lowes-Chair
  2. Terry Sabaka
  3. Mioara Mandea
  4. Sue MacMillan
  5. Vadim Golovkov

A motion to accept this group was made and seconded. The motion passed with one vote against it.

A motion was made to use the 7th generation IGRF (IGRF-95), updated to the year 2000 with the IGRF-95 secular variation model, as the fallback model. The motion was seconded and adopted nem con.

Charlie Barton announced that an IGRF 'health' warning will be placed on the IGRF Web page. The warning was written by Frank Lowes and will be 'wordsmithed' by Charlie Barton before being placed on the web page.

The chairman presented a brief report on magnetic repeat stations. A discussion of the need for high-resolution repeat data was deferred until the next IAGA meeting.

V. Papitashvilli made a motion to have his ad-hoc working group on geomagnetic variation models dissolved and absorbed into the V-8 working group. The motion also included a clause to consider the topics of the ad-hoc working group in the main working group. The motion was not acted on due to lack of time. Further discussion was postponed until the next IAGA meeting.

New officers were nominated. Mioara Mandea was nominated for the position of Chair of the working group. The nomination was seconded and unanimously approved. Sue MacMillan was nominated as Co-Chair of the working group. The nomination was seconded and unanimously approved.

The outgoing chair was given a hearty round of applause for a job well done. The meeting adjourned at 21:20.

Vietnam 2001 proposed sessions: (note: actual sessions will be posted on the IAGA web site)

  1. Main Field and Secular Variation Models at Earth's Surface and CMB. (V + I)
  2. The Geomagnetic Crustal Field in Satellite Data. (V)
  3. Geomagnetic Field Variation Models.   (V-8 + III)

Mioara Mandea tel. +33 238 339 500
Observatoire Magnetique National; fax. +33 238 339 504
Carrefour des 8 routes email:
45340 Chambon la Foret

For page content questions please contact: Susan Macmillan
Webpage Maintained by: Susan McLean
Hosted by: WDC for Solid Earth and Geophysics

Revised: 18 September, 2003

IUGG  > IAGA  > Division V  > Working Group V-MOD  > Minutes  > Birmingham 1999