MIRAI MR13-05 Total Magnetic Intensity (TMI)

Last Modified: 2018-05-12
: MR13-05
: Processed (DMO)-Corrected
: JAMSTEC
: Total magnetic field intensity
:
OCEANS > MARINE GEOPHYSICS > MARINE MAGNETICS
SOLID EARTH > GEOMAGNETISM

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2013-08-17 05:10 – 2013-08-18 21:23

Instrument:
Cesium magnetometer
The cesium vapor magnetometer measures the total magnetic by using electron paramagnetic resonance. In order to avoid the ship's magnetization, the instrument is towed by the vessel about 400 - 500m. As a quality control, data of low reliability was removed (see section 5. for quality control criteria). Synthetic geomagnetic field values were calculated from IGRF models.
Manufacturer : Geometrics, inc.
Type : G-882
Measurement range : 20,000 - 100,000 nT
Resolution : 0.002 nT
Accuracy : less than 2 nT
Location : Dry Laboratory
The following corrections and calculations were performed.

(1) International Geomagnetic Reference Field (IGRF)
Synthetic geomagnetic field values are calculated from IGRF 12th generation models by using navigation data ; latitude, longitude and date.
Reference:IAGA Division V-MOD Geomagnetic Field Modeling[http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html]

(2) Calculation of the geomagnetic field anomaly
An = F - Figrf
An: Total geomagnetic field intensity anomaly
F: Observed total geomagnetic field intensity
Figrf: Synthetic total geomagnetic field intensity from IGRF

(3) Output of the data
Time (UTC)
Latitude (degree)
Longitude (degree)
Observed total magnetic field intensity (nT)
Total geomagnetic field intensity anomaly (nT)
Following criteria were used for removal of data of low reliability:
⋅Time error (inversion of time, continuation of same timestamps)
⋅Ground speed of the ship below 1knot or exceeding 20knot
⋅Total geomagnetic field intensity anomaly exceeding ±4000nT
⋅Spatial gradient of the total geomagnetic field intensity anomaly exceeding ±300nT/km
(1) File naming rule: Cruise ID_corr.tmag
(2) Sampling rate: 1 second(It depends on geomagnetic field intensity and inclination )
(3) Geodetic system: WGS84
(4) If you would like the raw data set, please contact us from "Contact Us" above.
: MR13-05
: Processed (DMO)-Corrected
: JAMSTEC
: Total magnetic field intensity
:
OCEANS > MARINE GEOPHYSICS > MARINE MAGNETICS
SOLID EARTH > GEOMAGNETISM

Observation Map

Imagery reproduced from ...

Data List

  File names
MR13-05_corr.tmag
: MR13-05
: Processed (DMO)-Corrected
: JAMSTEC

TMI Corrected

No. Column Content Format Unit Remarks
1 1 - 8 Date i4,i2,i2 YYYYMMDD (UTC)
2 10 -15 Time i2,i2,i2 hhmmss (UTC)
3 17 -25 Latitude f9.5 degree No sign for the northern hemisphere.
Negative for the southern hemisphere.
4 27 -36 Longitude f10.5 degree No sign for eastern hemisphere.
Negative for the western hemisphere.
5 38 -45 Observed total geomagnetic field intensity  f8.1 nT
6 46 -53 Total geomagnetic field intensity anomaly f7.1 nT

Related Information

Update History

2018-05-12
An observation data was registerd.
2015-08-26
An observation data was registerd.