# S5P_L2_CO

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `S5P_L2_CO` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
scan_subindex | int16 | {time} |  | pixel index (0-based) within the scanline
datetime_start | double | {time} | [seconds since 2010-01-01] | start time of the measurement
datetime_length | double |  | [s] | duration of the measurement
orbit_index | int32 |  |  | absolute orbit number
validity | int32 | {time} |  | processing quality flag
latitude | float | {time} | [degree_north] | latitude of the ground pixel center (WGS84)
longitude | float | {time} | [degree_east] | longitude of the ground pixel center (WGS84)
latitude_bounds | float | {time, 4} | [degree_north] | latitudes of the ground pixel corners (WGS84)
longitude_bounds | float | {time, 4} | [degree_east] | longitudes of the ground pixel corners (WGS84)
sensor_latitude | float | {time} | [degree_north] | latitude of the geodetic sub-satellite point (WGS84)
sensor_longitude | float | {time} | [degree_east] | longitude of the goedetic sub-satellite point (WGS84)
sensor_altitude | float | {time} | [m] | altitude of the satellite with respect to the geodetic sub-satellite point (WGS84)
solar_zenith_angle | float | {time} | [degree] | zenith angle of the Sun at the ground pixel location (WGS84); angle measured away from the vertical
solar_azimuth_angle | float | {time} | [degree] | azimuth angle of the Sun at the ground pixel location (WGS84); angle measured East-of-North
sensor_zenith_angle | float | {time} | [degree] | zenith angle of the satellite at the ground pixel location (WGS84); angle measured away from the vertical
sensor_azimuth_angle | float | {time} | [degree] | azimuth angle of the satellite at the ground pixel location (WGS84); angle measured East-of-North
altitude | float | {time, vertical} | [m] | altitude grid on which the radiative transfer calculations are done
pressure_bounds | float | {time, vertical, 2} | [Pa] | pressure boundaries of the layers of the vertical grid
surface_altitude | float | {time} | [m] | surface altitude
surface_altitude_uncertainty | float | {time} | [m] | surface altitude precision
surface_meridional_wind_velocity | float | {time} | [m/s] | northward wind
surface_zonal_wind_velocity | float | {time} | [m/s] | eastward wind
surface_pressure | float | {time} | [Pa] | surface pressure
CO_column_number_density | float | {time} | [mol/m^2] | vertically integrated CO column density
CO_column_number_density_uncertainty | float | {time} | [mol/m^2] | uncertainty of the vertically integrated CO column density (standard error)
CO_column_number_density_validity | int8 | {time} |  | continuous quality descriptor, varying between 0 (no data) and 100 (full quality data)
CO_number_density_avk | float | {time, vertical} | [m] | averaging kernel for the vertically integrated CO column density (for number density profiles)
CO_column_number_density_avk | float | {time, vertical} | [] | averaging kernel for the vertically integrated CO column density (for partial column number density profiles)
CO_column_number_density_apriori | float | {time, vertical} | [mol/m2] | carbon monoxide apriori profile as partial column number densities
H2O_column_number_density | float | {time} | [mol/m^2] | H2O total column density
H2O_column_number_density_uncertainty | float | {time} | [mol/m^2] | uncertainty of the H2O column density (standard error)
cloud_height | float | {time} | [m] | Scattering layer height
cloud_optical_depth | float | {time} | [] | Scattering optical thickness SWIR
snow_ice_type | int8 | {time} |  | surface snow/ice type; enumeration values: snow_free_land (0), sea_ice (1), permanent_ice (2), snow (3), ocean (4)
sea_ice_fraction | float | {time} | [] | sea-ice concentration (as a fraction)
index | int32 | {time} |  | zero-based index of the sample within the source product

## Ingestion options

The table below lists the available ingestion options for `S5P_L2_CO` products.

option name | legal values | description
--- | --- | ---
co | corrected | whether to ingest the ‘normal’ CO column (default) or the destriping corrected CO column (co=corrected); providing this option will only work with processor version >= 02.01.00 (otherwise an empty product is returned)
co_avk | number_density | whether to ingest the partial column number density column avk (default) for CO or the number density column avk (avk=number_density)

## Mapping description

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

field name | mapping description
--- | ---
scan_subindex | description | the scanline and pixel dimensions are collapsed into a temporal dimension; the index of the pixel within the scanline is computed as the index on the temporal dimension modulo the number of scanlines
datetime_start | path | /PRODUCT/time, /PRODUCT/delta_time[]
description | time converted from milliseconds since a reference time (given as seconds since 2010-01-01) to seconds since 2010-01-01 (using 86400 seconds per day); the time associated with a scanline is repeated for each pixel in the scanline
datetime_length | path | /@time_coverage_resolution
description | the measurement length is parsed assuming the ISO 8601 ‘PT%(interval_seconds)fS’ format
orbit_index | path | /@orbit
validity | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/processing_quality_flags[]
description | the uint32 data is cast to int32
latitude | path | /PRODUCT/latitude[]
longitude | path | /PRODUCT/longitude[]
latitude_bounds | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/latitude_bounds[]
longitude_bounds | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/longitude_bounds[]
sensor_latitude | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/satellite_latitude[]
description | the satellite latitude associated with a scanline is repeated for each pixel in the scanline
sensor_longitude | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/satellite_longitude[]
description | the satellite longitude associated with a scanline is repeated for each pixel in the scanline
sensor_altitude | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/satellite_altitude[]
description | the satellite altitude associated with a scanline is repeated for each pixel in the scanline
solar_zenith_angle | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/solar_zenith_angle[]
solar_azimuth_angle | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/solar_azimuth_angle[]
sensor_zenith_angle | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/viewing_zenith_angle[]
sensor_azimuth_angle | path | /PRODUCT/SUPPORT_DATA/GEOLOCATIONS/viewing_azimuth_angle[]
altitude | path | /PRODUCT/layer[], /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude[]
description | the vertical grid is inverted to make it ascending; height is converted to altitude by adding surface_altitude
pressure_bounds | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/pressure_levels[]
description | the vertical grid is inverted to make it ascending; the lower boundary of each layer is then taken from pressure_levels; the upper boundary is the lower boundary of the layer above or 1e-3 Pa for the upper most layer
surface_altitude | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude[]
surface_altitude_uncertainty | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude_precision[]
surface_meridional_wind_velocity | available | optional
condition | processor version >= 01.03.00
path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/northward_wind[]
surface_zonal_wind_velocity | available | optional
condition | processor version >= 01.03.00
path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/eastward_wind[]
surface_pressure | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/pressure_levels[]
description | the surface pressure is the pressure at the lowest pressure level
CO_column_number_density | path | /PRODUCT/carbonmonoxide_total_column[]
condition | co=corrected and processor version >= 02.01.00
path | /PRODUCT/carbonmonoxide_total_column_corrected[]
CO_column_number_density_uncertainty | path | /PRODUCT/carbonmonoxide_total_column_precision[]
CO_column_number_density_validity | path | /PRODUCT/qa_value
CO_number_density_avk | available | optional
condition | avk=number_density and processor version < 02.04.00
path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/column_averaging_kernel[]
description | the vertical grid is inverted to make it ascending
condition | avk=number_density and processor version >= 02.04.00
path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/column_averaging_kernel[]
description | the vertical grid is inverted to make it ascending and each element is multiplied by 1000 [m] so the column avk can be applied to number density profiles instead of partial column number density profiles
CO_column_number_density_avk | available | optional
condition | avk unset and processor version < 02.04.00
path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/column_averaging_kernel[]
description | the vertical grid is inverted to make it ascending and each element is divided by 1000 [m] so the column avk can be applied to partial column number density profiles instead of number density profiles
condition | avk unset and processor version >= 02.04.00
path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/column_averaging_kernel[]
description | the vertical grid is inverted to make it ascending
CO_column_number_density_apriori | available | optional
condition | processor version >= 02.04.00
path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/carbonmonoxide_profile_apriori[]
description | the vertical grid is inverted to make it ascending
H2O_column_number_density | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/water_total_column[]
H2O_column_number_density_uncertainty | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/water_total_column_precision[]
cloud_height | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/height_scattering_layer[]
cloud_optical_depth | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/scattering_optical_thickness_SWIR[]
snow_ice_type | available | optional
condition | processor version >= 02.07.00
path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/snow_ice_flag[]
description | 0: snow_free_land (0), 1-100: sea_ice (1), 101: permanent_ice (2), 103: snow (3), 255: ocean (4), other values map to -1
sea_ice_fraction | available | optional
condition | processor version >= 02.07.00
path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/snow_ice_flag[]
description | if 1 <= snow_ice_flag <= 100 then snow_ice_flag/100.0 else 0.0