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ACE SEPICA Hourly Particle Fluxes, ASCII


Availability: At NSSDC, Ready for Electronic Access

Time span: 1997-10-07 to 2002-08-23


This data collection contains hourly Level 2 data in ASCII text (compressed with gzip) format from the Solar Energetic Particle Ionic Charge Analyzer (SEPICA) instrument on the Advanced Composition Explorer (ACE) spacecraft. This data set includes all measurements from solar quiet and active periods. There is one cumulative file for all 27-day Bartels solar rotation intervals covered by the present data set. Data records contain hourly time averages of H, He, C, O, Ne, Mg, Si and Fe ion fluxes in units of particles/(cm2*sr*sec*Mev/nucleon). There are three energy channels for H ions at 0.7 - 3 MeV, eight for He at 0.4-2 MeV/nucleon, seven for C at 0.3-12 MeV/n, six for O at 0.5-7.2 MeV/n, four for Ne at 0.6-7.2 MeV/n, four to Mg at 0.8 - 6.0 MeV/n, four for Si at 0.8-5.2 MeV/n, and five for Fe at 0.1-3.1 MeV/n. Two of the He channels include contributions from a AM-241 calibration source in SEPICA and are dominated by source events during quiet times. Availability of specific ion and energy channels depends on instrument mode. A data value of -999.9 indicates bad or missing data for the given time period. The number of counts is also given from which the statistical uncertainties can be calculated. Statistical flux uncertainties are computed from flux/sqrt (N), where N is the number of counts or events during the averaging period. Current release notes on Level 2 processing are given in the text file sepica_release_notes.txt, and sepica_energy_bands.txt defines the energy ranges and mean energies for each data channel.

This collection is available on-line at:

Alternate Names

  • SEPICA Level-2 Hourly Flux,ASCII


  • Space Physics: Heliospheric Studies


  • 97-045A-04F

Additional Information



Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. Andrew J. DavisGeneral ContactCalifornia Institute of
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