[IGSMAIL-3324]: High-rate SolarMax IGS/GPS-campaign "HIRAC/SolarMax" finished

[Joachim.Feltens @ esa.int]

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IGS Electronic Mail      11 May 07:41:06 PDT 2001      Message Number 3324
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Author: Joachim Feltens
subject: High-rate SolarMax IGS/GPS-campaign "HIRAC/SolarMax".

Dr. Joachim Feltens                               Darmstadt, 11 April 2001
IGS Ionosphere Working Group Chairman
EDS at ESOC-FDD
Robert-Bosch-Strasse 5
D-64293 Darmstadt
GERMANY
e-mail: Joachim.Feltens @ esa.int



Subject: High-rate SolarMax IGS/GPS-campaign "HIRAC/SolarMax".



Hallo Iono_WGlers, dear IGS colleagues,


in my IGSmail #3091 of 8 November 2000 I proposed, together with Norbert
Jakowski from DLR Neustrelitz, to organize a dedicated IGS campaign for
recording high-rate GPS dual-frequency data with the global IGS ground
stations network in order to observe the ionosphere's behavior during the
current solar maxium.

Due to the increased solar activity an enhanced stream of electrically
charged particles is emitted by the Sun. The interaction of these solar
particles with the Earth upper atmosphere and with the geomagnetic field
induces phenomena within the ionosphere, which are very interesting from
the scientific point of view. The observation and interpretation of the
ionosphere's behavior under such conditions thus helps to better under-
stand ionosphere physics. Many of these phenomena in the ionosphere are
short-lived (e.g. travelling wave structures).

Due to the global IGS ground station network there exists now for the
first time an opportunity to observe ionospheric behavior by means of
dual-frequency GPS and GLONASS data on worldwide base. Ionosphere
scientists are thus very interested in using the dense IGS GPS ground
station network for that task.

The current solar maximum was thus identified as a unique chance, and
it was decided to run the high-rate campaign "HIRAC/SolarMax" from
23 - 27 April 2001: One or three-second sampling rate dual-frequency
GPS and GLONASS data were recorded at selected IGS sites to establish
a high-rate tracking database which will now be the subject of iono-
spheric analyses over years. Since a lot of ionospheric phenomena are
short-lived, they cannot be extracted with the standard thirty-second
sampling rate of the "classic" IGS RINEX files. - The IGS sponsored a
similar campaign during the solar eclipse on 11 August 1999. The re-
gions of major interest for the HIRAC/SolarMax Campaign were

  1. the polar regions,
  2. the low latitudes including the crest regions at both sides
         of the geomagnetic equator.

This IGS activity, organized by J. Feltens and C. Noll, was coordina-
ted with other ionospheric observation programs or measuring campaigns,
organized by N. Jakowski as part of COST activities, using e.g. NNSS
receiver chains, ionosondes, EISCAT and high resolution magnetometers
to get a comprehensive view of the geomagnetic and ionospheric state.

Initially it was planned to close the HIRAC/SolarMax Campaign on
27 April 24:00 UT. However, in the morning of 27 April an IPS message
arrived, telling that a large solar flare had been observed on 26 April,
which would impact the Earth on 28 and 29 April. So, at short notice,
the campaign was prolonged for two additional days to 29 April 24:00.

Now, after the end of the HIRAC/SolarMax Campaign I may express, as
chairman of the IGS Ionosphere Working Group, my thanks and appreciation
to all the IGS colleagues at the ground stations and data centers for
their efforts and their kind cooperation. Many thanks also to Carey Noll
for her efforts to archive all vast amount of data at CDDIS. These thanks
are also on behalf of Nobert Jakowski, DLR Neustrelitz, who originally
came to me with the idea to run a high-rate campaign during the current
solar maximum.

A list of the stations which participated in the HIRAC/SolarMax Campaign
and a map of these stations can be accessed under
   ftp://cddisa.gsfc.nasa.gov/pub/gps/01solarmax/solarmax_table.pdf resp.
   ftp://cddisa.gsfc.nasa.gov/pub/gps/01solarmax/solarmax_map.pdf.
The number of reporting stations is updated regularily in the table. So
far (11 May 2001) high-rate tracking data of 63 stations have been de-
livered to CDDIS, all in all around 4 Gbytes, and more and more data are
received at CDDIS every day. The high-rate GPS/GLONASS tracking data are
available at CDDIS through anonymous ftp to host cddisa.gsfc.nasa.gov in
the filesystem /gps/01solarmax/yyddd/yyt/hh, where yy is the two-digit
year, ddd is the three-digit day of year, t is the file type (d, g, m,
n, o, s), and hh is the hour 00 ... 23. A RINEX description can be found
at "ftp://igscb.jpl.nasa.gov/igscb/data/format/rinex210.txt";

Questions about the campaign and requests for establishing contacts be-
tween the IGS and non-IGS groups, which participated in the campaign,
for cooperation, can be directed to
   Dr. Joachim Feltens  <Joachim.Feltens @ esa.int> and/or
   Dr. Norbert Jakowski <Norbert.Jakowski @ dlr.de>;
questions about data access can be directed to the CDDIS Manager
   Carey Noll <noll @ cddis.gsfc.nasa.gov>.


Many thanks again and best regards           Joachim Feltens