Read Me

General Information on the MACCS Program

These web pages contain magnetometer data from the Magnetometer Array for Cusp and Cleft Studies (MACCS), an array of magnetometers in Arctic Canada run by Boston University and Augsburg College with assistance from the University of Alberta and the Geological Survey of Canada, and supported by the National Science Foundation's Magnetospheric Physics Program. Further details of the MACCS array can be found in W. J. Hughes and M. J. Engebretson, MACCS: Magnetometer Array for Cusp and Cleft Studies, in Satellite-Ground Based Coordination Sourcebook, (eds. M. Lockwood, M.N. Wild H. J. Opgenoorth), ESA-SP-1198, pp. 119-130, 1997

The MACCS data request page contains data at 5 second resolution. Vector magnetic field samples were obtained eight times a second, and the data originally recorded as 0.5 second averages. This data set is averaged over the 5 second interval centered on the time of the given measurement. The data, originally recorded in local geomagnetic coordinates, have been rotated into geographic coordinates. Similarly, the plots produced by the MACCS data request page are made from 5 second resolution data in geographic coordinates. All data provided have been subjected to routine quality checks, but these may not catch all errors. Persons wishing to use MACCS data in publications or presentations should contact one of the MACCS investigators to verify the quality of these data.

MACCS Investigators

Dr. Mark Engebretson engebret@augsburg.edu
Dr. W. J. Hughes hughes@bu.edu

The following information is included in this readme file:

1. Station Coordinates.
2. 5 second binary file structure.
3. Information about IDL code included on this page.
4. Information about potential timing erros.


1. Table of the MACCS station codes and locations.

The Magnetic Observatories of the Geological Survey of Canada are included in the list and denoted with an asterisk. The magnetic coordinates are altitude adjusted corrected magnetic coordinates (aagcm) computed with code provided by the Johns Hopkins University Applied Physics Laboratory using the epoch 1995 IGRF. The UT time of noon MLT was computed using a 1991 Tsyganenko model.

MACCS Magnetometer Station Coordinates

Station Name
Geographic
Corrected
Geomagnetic
T-Model Local
Magnetic Noon
Latitude
Longitude
Latitude
Longitude
Pangnirtung (PGG)
66.1
294.2
74.2
19.4
15:50
Clyde River (CRV)
70.5
291.4
78.7
17.6
15:57
Iqaluit (IQA)*
63.8
291.5
72.3
14.6
16:09
Cape Dorset (CDR)
64.2
283.4
73.5
1.7
16:55
Nain (NAN)
56.4
298.3
64.2
22.0
15:40
Igloolik (IGL)
69.3
278.2
78.5
352.9
17:25
Coral Harbour (CHB)
64.1
276.8
73.7
350.5
17:34
Repulse Bay (RBY)
66.5
273.8
76.0
345.0
17:52
Pelly Bay (PEB)
68.5
270.3
77.7
338.1
18:15
Baker Lake (BLC)*
64.3
264.0
73.5
328.6
18:48
Gjoa Haven (GJO) 
68.6
264.1
77.5
326.6
18:54
Resolute Bay (RES)*
74.7
265.0
83.0
321.6
19:11
Cambridge Bay (CBB)*
69.1
255.0
76.9
310.6
19:51

 

*These stations are Canadian Magnetic Observatories operated by the Geomagnetism Unit of the Geological Survey of Canada. Because these data complement the MACCS data, they are available to the GEM community courtesy of the Geological Survey of Canada and may be obtained by contacting either Dr. Mark Engebretson engebret@augsburg.edu or Dr. W. J. Hughes hughes@bu.edu .

ANY USE OF THESE DATA MUST INCLUDE A PROPER ACKNOWLEDGEMENT OF THEIR SOURCE.


2. The 5 second data files are in binary format. Each 5 sec file contains data for one day for a single station. The naming convention is: 3 letter station abbreviation followed by yearday with the extension '.bin' (meaning binary data) such as 'gjo95154.bin'.

The record format of those 5 second binary data files is:

record size(fixed) = 15 bytes
number of records per file = 17280
file size = 259200 bytes
flag for bad or missing data = 32767000

Byte Number Content Data Type
1 hour byte
2 minute byte
3 second byte
4-7 Bx(nT x 1000) 4 byte longint
8-11 By(nT x 1000) 4 byte longint
12-15 Bz(nT x 1000) 4 byte longint



3. There is also an IDL program (sec_conv.pro), which will convert the 5 second files from binary to ascii.

4. Note: Several MACCS stations lost GPS coverage for part of 2002 and 2003. Time stamps during GPS outages were provided by the local computer clock, which can result in timing errors of several seconds. At no time do we believe these errors exceed 30 seconds. This data is included on this site as the timing accuracy is sufficient for many scientific purposes. However, this data should NOT BE USED for studies that require GPS time accuracy.