The raw data from POLSCAT/CLPX flights have been processed to produce the normalized radar cross section (σ0) of the terrain. Data from each flight line are saved in a fixed-width ASCII text file containing 24 columns, of which only the first 12 are relevant to CLPX: 

Column 1: POLSCAT instrument time in sec (UT time) from the beginning of the day
Column 2: Aircraft GPS time in sec (UT) from the beginning of the day
Column 3: Latitude of the antenna footprint in degrees
Column 4: Longitude of the antenna footprint in degrees
Column 5: Azimuth angle of the vector from the antenna to the antenna footprint (0 degrees at north)
Column 6: Polarization roll angle in degrees
Column 7: Range from the antenna footprint to aircraft in meters
Column 8: Incidence angle in degrees
Column 9: σVV in dB, the σ0 for vertically polarized transmit and vertically polarized receive
Column 10: σHH in dB, the σ0 for horizontally polarized transmit and horizontally polarized receive
Column 11: σHV in dB, the σ0 for vertically polarized transmit and horizontally polarized receive
Column 12: σVH in dB, the σ0 for horizontally polarized transmit and vertically polarized receive

Note that σHV is supposed to be identical to σVH. The measurements agree with this expectation very well; the difference between measured σHV and σVH is within 0.2 dB most of the time, which is within the sensitivity of the POLSCAT system operating on the DC-8 aircraft.

Each data file has eight numbers in its filename, incorporating the date and time of data collection (mmddhhmm). The first four numbers of the filename represent the month 'mm' and day of month 'dd' and the last four indicate the start time (UT) of each flight line (hhmm). For example, the filename of a flight line commencing at 16:15 on 19 February is 02191615. Files are in directories by year (2002 and 2003).

Flights were flown over the Fraser, North Park, and Rabbit Ears MSAs of the CLPX. Flight lines are matched to data files in the Flight Summaries section of this document.

The parameter presented in this data set is backscatter return from a Ku-band polarimetric scatterometer, measured in decibels (dB). This is not a direct measurement of SWE.