# GOME_L1_EXTRACTED

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `GOME_L1_EXTRACTED` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
datetime_stop | double | {time} | [seconds since 2000-01-01] | time of the measurement at the end of the integration time
datetime_length | double | {time} | [s] | length of each measurement
orbit_index | int32 |  |  | absolute orbit number
latitude | double | {time} | [degree_north] | tangent latitude of the measurement
longitude | double | {time} | [degree_east] | tangent longitude of the measurement
latitude_bounds | double | {time, 4} | [degree_north] | corner latitudes for the ground pixel of the measurement
longitude_bounds | double | {time, 4} | [degree_east] | corner longitudes for the ground pixel of the measurement
wavelength_photon_radiance | double | {time, spectral} | [count/s/cm2/sr/nm] | measured radiances
wavelength_photon_radiance_uncertainty | double | {time, spectral} | [count/s/cm2/sr/nm] | absolute radiance measurement error
wavelength | double | {time, spectral} | [nm] | nominal wavelength assignment for each of the detector pixels
integration_time | double | {time, spectral} | [s] | integration time for each pixel
scan_subindex | int8 | {time} |  | relative index (0-3) of this measurement within a scan (forward+backward)
scan_direction_type | int8 | {time} |  | scan direction for each measurement; enumeration values: forward (0), backward (1)
solar_zenith_angle | double | {time} | [degree] | solar zenith angle at instrument
solar_azimuth_angle | double | {time} | [degree] | solar azimuth angle at instrument
viewing_zenith_angle | double | {time} | [degree] | line of sight zenith angle at instrument
viewing_azimuth_angle | double | {time} | [degree] | line of sight azimuth angle at instrument
index | int32 | {time} |  | zero-based index of the sample within the source product

## Ingestion options

The table below lists the available ingestion options for `GOME_L1_EXTRACTED` products.

option name | legal values | description
--- | --- | ---
band | band-1a, band-1b, band-2a, band-2b, band-3, band-4, blind-1a, straylight-1a, straylight-1b, straylight-2a | only include data from the specified band (‘band-1a’, ‘band-1b’, ‘band-2a’, ‘band-2b’, ‘band-3’, ‘band-4’, ‘blind-1a’, ‘straylight-1a’, ‘straylight-1b’, ‘straylight-2a’); by default data from all bands is retrieved
data | sun_reference | retrieve the measured radiances (default) or the sun spectra (data=sun_reference)

This definition is only applicable when: data unset

## Mapping description

GOME Level 1 Extracted Spectra

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

field name | mapping description
--- | ---
datetime_stop | path | /egp[]/agi/groundpixel_end
datetime_length | description | set to fixed value of 1.5 [s]
orbit_index | path | /pir/start_orbit
latitude | path | /egp[]/agi/coords[4]/latitude
description | tangent latitude of the measurement
longitude | path | /egp[]/agi/coords[4]/longitude
description | tangent longitude of the measurement
latitude_bounds | path | /egp[]/agi/coords[0:3]/latitude
description | The corners are rearranged in the following way: 1,3,2,0
longitude_bounds | path | /egp[]/agi/coords[0:3]/longitude
description | The corners are rearranged in the following way: 1,3,2,0
wavelength_photon_radiance | path | /egp[]/brda[]/edr[]/abs_radiance
description | will be set to NaN is brda record is not available or if egp[]/brda[]/edr[]/flag != 0
wavelength_photon_radiance_uncertainty | path | /egp[]/brda[]/edr[]/abs_rad_err
description | will be set to NaN is brda record is not available or if egp[]/brda[]/edr[]/flag != 0
wavelength | path | /egp[]/brda[]/edr[]/wavelength
integration_time | path | /egp[]/brda[]/integration_time
scan_subindex | path | /egp[]/sub_counter
description | if a measurement consisted of multiple ground pixels, the subset counter of the last pixel is taken
scan_direction_type | path | /egp[]/sub_counter
description | the scan direction is based on the subset counter of the measurement; 0-2: forward (0), 3: backward (1)
solar_zenith_angle | path | /egp[]/agi/solar_angles_spacecraft/zenith_b
solar_azimuth_angle | path | /egp[]/agi/solar_angles_spacecraft/azimuth_b
viewing_zenith_angle | path | /egp[]/agi/los_spacecraft/zenith_b
viewing_azimuth_angle | path | /egp[]/agi/los_spacecraft/azimuth_b