IMPACTS CoSMIR data ReadMe file
Year 2 of campaign: 2022
Contact: Rachael Kroodsma, rachael.a.kroodsma@nasa.gov

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Instrument description:
Programmable scanning radiometer with 9 channels. 
Frequencies centered at 50.3, 52.8, 89.0, 165.5, 183.31+/-1, 183.31+/-3, and 183.31+/-7 GHz. 
89.0 and 165.5 channels have both horizontal and vertical polarization, all other channels only horizontal.

Data description:
NetCDF files
Separate files given for each scan type
Two scan types:
(1) Forward conical
(2) Along-track

Datasets name, size, unit, and description given below.
Missing value: -999
Aircraft (AC) parameters taken from the ER-2 IWG1 nav file. Interpolated to CoSMIR pixels.
IWG1 files located at: https://asp-archive.arc.nasa.gov/IMPACTS/N809NA/

Size description:
chan = 9, number of channels in order of 50.3, 52.8, 89v, 89h, 165v, 165h, 183+/-1, 183+/-3, 183+/-7
pixel = 151 forward conical, 101 along-track, number of pixels in each scan line
scan = varies, number of scan lines in each flight

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Datasets in NetCDF files:

Year, Size: [pixel,scan], Unit: year, Description: year (UTC)
Month, Size: [pixel,scan], Unit: month, Description: month (UTC)
DayOfMonth, Size: [pixel,scan], Unit: day, Description: day of month (UTC)
Hour, Size: [pixel,scan], Unit: hour, Description: hour of day (UTC)
Minute, Size: [pixel,scan], Unit: minute, Description: minute (UTC)
Second, Size: [pixel,scan], Unit: second, Description: second (UTC)
MilliSecond, Size: [pixel,scan], Unit: ms, Description: millisecond (UTC)

AC_Altitude, Size: [pixel,scan], Unit: meters, Description: aircraft GPS altitude
AC_Pitch, Size: [pixel,scan], Unit: degrees, Description: aircraft pitch
AC_Roll, Size: [pixel,scan], Unit: degrees, Description: aircraft roll
AC_Heading, Size: [pixel,scan], Unit: degrees, Description: aircraft heading
AC_Latitude, Size: [pixel,scan], Unit: degrees, Description: aircraft latitude
AC_Longitude, Size: [pixel,scan], Unit: degrees, Description: aircraft longitude
AC_Speed, Size: [pixel,scan], Unit: meters/second, Description: aircraft ground speed

Tb, Size: [chan,pixel,scan], Unit: Kelvin, Description: Calibrated brightness temperatures
IncidenceAngle, Size: [pixel,scan], Unit: degrees, Description: earth incidence angle of CoSMIR
Latitude, Size: [pixel,scan], Unit: degrees, Description: latitude of CoSMIR center of footprint
Longitude, Size: [pixel,scan], Unit: degrees, Description: longitude of CoSMIR center of footprint
Azimuth, Size: [pixel,scan], Unit: degrees, Description: azimuth angle of CoSMIR with respect to the aircraft
Elevation, Size: [pixel,scan], Unit: degrees, Description: elevation angle of CoSMIR with respect to the aircraft

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Scan mode description:

Azimuth and Elevation angles are with respect to the aircraft. They do not take into account aircraft pitch, roll, or heading
Conical scan off-nadir angle set at 49.2 degrees for all flights

Forward conical scans left to right. Azimuth angle -90 to +90 and Elevation angle +49.2
Along-track scans fore to aft. Azimuth angle +180 and Elevation angle +49.2 to -49.2