CASSIOPE SPACECRAFT (Swarm-E)
PROCESSED DATA HANDBOOK

GAP Ionospheric Density Profile netCDF File

The GAP ionPrf netCDF file provides ionosphere electron density profiles derived from standard Abel inversion of Line-of-Site TEC measurements taken during radio occultation events. Electron density profiles of GAP were validated in Watson, C., et al., (2018) Enhanced Polar Outflow Probe ionospheric radio occultation measurements at high latitudes: Receiver bias estimation and comparison with ground-based observations, Radio Science, 53, 10.1002/2017RS006453.

Filename Format

“GAP_yyyymmdd_HHMMSS_hhmmss _ionPrf_RCVRr_V.v.r.nc”

• r: GAP Receiver number (0-3=GAP-A; 4=GAP-O)
• mm: File month
• dd: File day
• yyyy: File year
• HH: File start hour (UT)
• MM: File start minute (UT)
• SS: File start second (UT)
• hh: File end hour (UT)
• mm: File end minute (UT)
• ss: File end second (UT)
• V: Major code version
• v: Minor code version
• r: Reprocessing count

Global Attributes

• Month (integer): Month of file
• Day (integer): Day of file
• Year (integer): Year of file
• RCVR (integer): GAP Receiver number (0-3=GAP-A; 4=GAP-O)
• Start_Time (double): Data start time (hours of UT)
• End_Time (double): Data end time (hours of UT)
• PRN (integer): GPS satellite PRN

Variables

• ALT (double): Mean sea level altitude of occultation tangent point (km)
• GEO_LON (double): Geographic longitude of occultation point (degrees)
• GEO_LAT (double): Geographic latitude of occultation point (degrees)
• LOS_TEC (double): Calibrated line-of site TEC (TECU)
• EDEN (double): Electron Density (m^-3)