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License: Creative Commons Attribution 4.0 International (CC BY 4.0), 
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Citation: 
Michaelis, I.; Rother, M.; Korte, M. (2024): CHAMP ME Orbit Counter. V. 0101. GFZ Data Services. https://doi.org/...

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This dataset is an add-on to the CHAMP Level 3 Magnetic/Electric Field (ME) data files of the `LEO' satellite 'CHAMP'. It contains the date, time and location of the CHAMP satellite when crossing the equator in ascending direction. The data has been derived from high precision GPS position measurements (RSO and PDO). Small gaps have been interpolated, larger gaps have been filled using orbit prediction from NASA-SPDF. The file format is cdf (NASA cdf) and contains all meta data for description, the content is an extended version of the SW_OPER_AUXAORBCNT product from Swarm satellite mission. Magnetic local time (MLT) at the equator crossing has been calculated using Emmert et. al (2010). 
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The data is provided in NASA CDF format (https://cdf.gsfc.nasa.gov/).
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File name:

For example:
CH_ME_ORBCNT_20000726T003629_20100918T232748_0101.cdf

CH:              CHAMP (satellite identifier)
ME:             Magnetic/Electric Field
20000726T003629: yyyymmddThhhhhh (time of first entry)
20100918T232748: yyyymmddThhhhhh (time of last entry)
0101:            version 0101 (version identifier)
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References:

Rother, M., & Michaelis, I. (2019). CH-ME-3-MAG - CHAMP 1 Hz Combined Magnetic Field Time Series (Level 3) [dataset]. GFZ Data Services. https://doi.org/10.5880/GFZ.2.3.2019.004 
Emmert, J. T., A. D. Richmond, and D. P. Drob (2010), A computationally compact representation of Magnetic-Apex and Quasi-Dipole coordinates with smooth base vectors, J. Geophys. Res., 115, A08322, doi:10.1029/2010JA015326. 
NASA Space Physics Data Facility: CDF Format Page https://cdf.gsfc.nasa.gov/
NASA Satellite Situation Center Web: https://sscweb.gsfc.nasa.gov/cgi-bin/Locator.cgi

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Access:
ftp://isdcftp.gfz-potsdam.de/champ/ME/Level3/ORBCNT/

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Contact:

Monika Korte (monika.korte@gfz-potsdam.de)
Ingo Michaelis (ingo.michaelis@gfz-potsdam.de)