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Name Template: PUB/MISSION/level1b/occTab/occTab_YYYY.DDD.LLL.NN_SSSS.VVVV_nc

DDDDay of year
IIIIMission ID (CHAM, SACC, CO01-06, GPSM, etc)
LLLLEO number (1-6 for COSMIC)
MISSIONMission ID (eight characters or less--champ, champrt, sacc, sacctst, etc)
NNDump number since midnight
PUBBase directory for the pub hierarchy
SSSSSubtype (an ID which tells the command options used in generating this file)
VVVVVersion (an ID which tells the version of all codes using in generating thie file)
YYYYYear

Atmospheric and ionospheric occultation table. Contains information about which occultations exist in a given download (one dump of data for one LEO) and where and when they occured.

This table is in netCDF format (see http://www.unidata.ucar.edu/packages/netcdf/index.html for more details). The data file contains global attributes which describe the entire dump, as well as profile-based data which include one value per occultation which occurred during the period covered by the data download.

Global Data


start_time

  • Description:Starting time of the data download in GPS seconds
  • Data Type: 64 bit double precision floating point
  • Units: GPS seconds

end_time

  • Description:Ending time of the data download in GPS seconds
  • Data Type: 64 bit double precision floating point
  • Units: GPS seconds

dump_id

  • Description: The ID of this LEO download. YYYY.DDD.SSS.NN, where YYYY = year, DDD = Day of year, SSS = LEO ID and NN = Dump number that day The LEO ID is unique for a satellite (i.e. when a satellite re-enters the atmosphere, that number is never reused). Numbering starts with 1.
  • Data Type: 15 byte character

Profile Data


azimuth

  • Description:Occultation Azimuth: Angle between the LEO velocity vector and the projection of the LEO->GPS vector onto the LEO local plane. Measured from the LEO velocity vector clockwise looking down towards the Earth.
  • Data Type: float
  • Units: degrees , -180 to 180
  • Missing Value: -999

early_occ

  • Description:Flag: Occ starts before start of dump
  • Data Type: byte
  • Units: boolean: 0 or 1
  • Missing Value: 255

ion_data_stop

  • Description:Stop of MR data for ion occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

ref_sat

  • Description:Reference GPS satellite PRN
  • Data Type: byte
  • Units: Unitless
  • Missing Value: 255

atm_perigee_lon

  • Description:Longitude of perigee point at bottom of atm occ
  • Data Type: float
  • Units: degrees East, -180 to 180
  • Missing Value: -999

atm_start_time

  • Description:Start time of Atmospheric occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

occ_id

  • Description:Occultation ID per dump
  • Data Type: long
  • Units: Unitless
  • Missing Value: -999

ion_perigee_lat

  • Description:Latitude of perigee point at bottom of ion occ
  • Data Type: float
  • Units: degrees North, -90 to 90
  • Missing Value: -999

atm_perigee_lat

  • Description:Latitude of perigee point at bottom of atm occ
  • Data Type: float
  • Units: degrees North, -90 to 90
  • Missing Value: -999

atm_data_stop

  • Description:Stop of HR data for atm occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

ion_perigee_lon

  • Description:Longitude of perigee point at bottom of ion occ
  • Data Type: float
  • Units: degrees East, -180 to 180
  • Missing Value: -999

ion_start_time

  • Description:Start time of Ionospheric occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

atm_data_start

  • Description:Start of HR data for atm occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

atm_stop_time

  • Description:Stop time of Atmospheric occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

setting

  • Description:Flag: 0 if rising, 1 if setting
  • Data Type: byte
  • Units: Unitless
  • Missing Value: 255

occ_type

  • Description:Type = one byte: 00XXXXXX, where: 0x01 = atmospheric occ (has hr data, ref sat data and fid site data) 0x02 = has mr data (ionospheric occ) 0x04 = has hr data 0x08 = has ref sat data 0x10 = has fid data 0x20 = covers ionosphere (low rate ion occ)
  • Data Type: byte
  • Units: Unitless
  • Missing Value: 255

ion_data_start

  • Description:Start of MR data for ion occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

fid_id

  • Description:Fiducial (ground GPS) site 4 character ID
  • Data Type: byte
  • Units: Unitless
  • Missing Value: XXXX

ion_stop_time

  • Description:Stop time of Ionospheric occ
  • Data Type: double
  • Units: GPS seconds
  • Missing Value: -999

occ_sat

  • Description:Occulting GPS satellite PRN
  • Data Type: byte
  • Units: Unitless
  • Missing Value: 255

late_occ

  • Description:Flag: Occ ends after end of dump
  • Data Type: byte
  • Units: boolean: 0 or 1
  • Missing Value: 255