# GOMOS_L1_TRANSMISSION

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `GOMOS_L1_TRANSMISSION` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
datetime_start | double | {time} | [seconds since 2000-01-01] | start time of the measurement
datetime_length | double |  | [s] | integration time for a readout
orbit_index | int32 |  |  | absolute orbit number
latitude | double | {time} | [degree_north] | latitude of the apparent tangent point
longitude | double | {time} | [degree_east] | longitude of the apparent tangent point
altitude | double | {time} | [m] | altitude of the apparent tangent point
wavelength_photon_transmittance | double | {time, spectral} | [(count/s/cm2/nm)/(count/s/cm2/nm)] | wavelength photon transmittance of each spectrum measurement
wavelength_photon_transmittance_uncertainty | double | {time, spectral} | [(count/s/cm2/nm)/(count/s/cm2/nm)] | error in the wavelength photon transmittance of each spectrum measurement
wavelength | double | {spectral} | [nm] | nominal wavelength assignment for each of the detector pixels
sensor_latitude | double | {time} | [degree_north] | latitude of the satellite position at half-measurement
sensor_longitude | double | {time} | [degree_east] | longitude of the satellite position at half-measurement
sensor_altitude | double | {time} | [m] | altitude of the satellite at half-measurement
scene_type | int8 |  |  | illumination condition for each profile; enumeration values: dark (0), bright (1), twilight (2), straylight (3), twilight_straylight (4)
index | int32 | {time} |  | zero-based index of the sample within the source product

## Mapping description

GOMOS Level 1 products only contain a single profile; all measured transmission data will be provided in order from high altitude to low altitude in the profile

The table below details where and how each variable was retrieved from the input product.

field name | mapping description
--- | ---
datetime_start | path | /tra_transmission/dsr_time
datetime_length | path | /sph/samp_duration
orbit_index | path | /mph/abs_orbit
latitude | path | /tra_geolocation/tangent_lat[1]
longitude | path | /tra_geolocation/tangent_long[1]
altitude | path | /tra_geolocation/tangent_alt[1]
wavelength_photon_transmittance | path | /tra_transmission[]/trans_spectra[]
wavelength_photon_transmittance_uncertainty | path | /tra_transmission[]/cov[]
description | the square root of the variance values are taken to provide the standard uncertainty
wavelength | path | /tra_nom_wav_assignment[]/nom_wl[]
sensor_latitude | path | /tra_geolocation/lat[1]
sensor_longitude | path | /tra_geolocation/longit[1]
sensor_altitude | path | /tra_geolocation/alt[1]
scene_type | condition | CODA product version 0
path | /tra_summary_quality[0]/limb_flag
condition | CODA product version 1 and higher
path | /tra_summary_quality[0]/obs_illum_cond