# GOMOS_L1_LIMB

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `GOMOS_L1_LIMB` 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_radiance | double | {time, spectral} | [count/s/cm2/nm/nsr] | background spectral photon radiance of each spectrum measurement
wavelength_photon_radiance_uncertainty | double | {time, spectral} | [count/s/cm2/nm/nsr] | error in the background spectral photon radiance 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
sensor_longitude | double | {time} | [degree_east] | longitude of the satellite
sensor_altitude | double | {time} | [m] | altitude of satellite
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

## Ingestion options

The table below lists the available ingestion options for `GOMOS_L1_LIMB` products.

option name | legal values | description
--- | --- | ---
spectra | upper, lower | retrieve the upper (default, spectra=upper) or lower (spectra=lower) background spectra
corrected | false | retrieve the corrected (default) or uncorrected (corrected=false) background spectra

## Mapping description

GOMOS Level 1 products only contain a single profile; all measured profile points 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 | /lim_mds/dsr_time
datetime_length | path | /sph/samp_duration
orbit_index | path | /mph/abs_orbit
latitude | path | /lim_ads/tangent_lat[]
longitude | path | /lim_ads/tangent_long[]
altitude | path | /lim_ads/tangent_alt[]
wavelength_photon_radiance | condition | spectra=upper and corrected=false
path | /lim_mds[]/up_low_back_no_corr[0,], /lim_occultation_data[0]/abs_rad_sens_curve_limb[], /lim_occultation_data[0]/rad_sens_curve_limb[], /lim_ads[]/off_back, /lim_ads[]/gain_back
description | radiance = (off_back + up_low_back_no_corr / gain_back) * interp(abs_rad_sens_curve_limb, rad_sens_curve_limb, nom_wl)
condition | spectra=lower and corrected=false
path | /lim_mds[]/up_low_back_no_corr[1,], /lim_occultation_data[0]/abs_rad_sens_curve_limb[], /lim_occultation_data[0]/rad_sens_curve_limb[], /lim_ads[]/off_back, /lim_ads[]/gain_back
description | radiance = (off_back + up_low_back_no_corr / gain_back) * interp(abs_rad_sens_curve_limb, rad_sens_curve_limb, nom_wl)
condition | spectra=upper and corrected=true
path | /lim_mds[]/up_low_back_corr[0,], /lim_occultation_data[0]/abs_rad_sens_curve_limb[], /lim_occultation_data[0]/rad_sens_curve_limb[], /lim_ads[]/off_back, /lim_ads[]/gain_back
description | radiance = (off_back + up_low_back_corr / gain_back) * interp(abs_rad_sens_curve_limb, rad_sens_curve_limb, nom_wl)
condition | spectra=lower and corrected=true
path | /lim_mds[]/up_low_back_corr[1,], /lim_occultation_data[0]/abs_rad_sens_curve_limb[], /lim_occultation_data[0]/rad_sens_curve_limb[], /lim_ads[]/off_back, /lim_ads[]/gain_back
description | radiance = (off_back + up_low_back_corr / gain_back) * interp(abs_rad_sens_curve_limb, rad_sens_curve_limb, nom_wl)
wavelength_photon_radiance_uncertainty | condition | spectra=upper
path | /lim_mds[]/err_up_low_back_corr[0,]
description | uncertainty = (err_up_low_back_corr / 100) * wavelength_photon_radiance
condition | spectra=lower
path | /lim_mds[]/err_up_low_back_corr[1,]
description | uncertainty = (err_up_low_back_corr / 100) * wavelength_photon_radiance
wavelength | path | /lim_nom_wav_assignment[]/nom_wl[]
description | Will be set to nm
sensor_latitude | path | /lim_ads/lat[]
sensor_longitude | path | /lim_ads/longit[]
sensor_altitude | path | /lim_ads/alt[]
scene_type | condition | CODA product version 0
path | /lim_summary_quality[0]/limb_flag
condition | CODA product version 1 and higher
path | /lim_summary_quality[0]/obs_illum_cond