S5P_L2_CH4
Variables
The table below lists the variables that are present in the HARP product that results from an ingestion of S5P_L2_CH4 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_bounds | float | {time, vertical, 2} | [m] | altitude bounds per profile layer |
| pressure_bounds | float | {time, vertical, 2} | [Pa] | pressure bounds per profile layer |
| surface_altitude | float | {time} | [m] | surface altitude |
| surface_altitude_uncertainty | float | {time} | [m] | surface altitude precision |
| surface_pressure | float | {time} | [Pa] | surface pressure |
| CH4_column_volume_mixing_ratio_dry_air | float | {time} | [ppbv] | column averaged dry air mixing ratio of methane |
| CH4_column_volume_mixing_ratio_dry_air_uncertainty | float | {time} | [ppbv] | uncertainty of the column averaged dry air mixing ratio of methane (1 sigma error) |
| CH4_column_volume_mixing_ratio_dry_air_validity | int8 | {time} | continuous quality descriptor, varying between 0 (no data) and 1 (full quality data) | |
| CH4_column_volume_mixing_ratio_dry_air_avk | float | {time, vertical} | [] | column averaging kernel for methane retrieval |
| CH4_column_number_density_apriori | float | {time, vertical} | [mol/m2] | a-priori column number density profile of methane |
| dry_air_column_number_density | float | {time, vertical} | [mol/m2] | column number density profile of dry air |
| 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_fraction | float | {time} | [] | cloud fraction from VIIRS data in the SWIR channel for the instantaneous field of view |
| aerosol_height | float | {time} | [m] | aerosol height parameter in the CH4 retrieval |
| aerosol_optical_depth | float | {time} | [] | aerosol optical thicknesss in the SWIR band |
| 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_CH4 products.
| option name | legal values | description |
|---|---|---|
| ch4 | bias_corrected | whether to ingest the ‘normal’ CH4 column vmr (default) or the bias corrected CH4 column vmr (ch4=bias_corrected) |
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_bounds | condition | processor version >= 01.00.00 |
| path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/altitude_levels[] | |
| description | derived from height per level (layer boundary) by repeating the inner levels; the upper bound of layer k is equal to the lower bound of layer k+1; the vertical grid is inverted to make it ascending | |
| condition | processor version < 01.00.00 | |
| path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/height_levels[] | |
| description | derived from height per level (layer boundary) by repeating the inner levels; the upper bound of layer k is equal to the lower bound of layer k+1; the vertical grid is inverted to make it ascending | |
| pressure_bounds | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_pressure[],/PRODUCT/SUPPORT_DATA/INPUT_DATA/pressure_interval[] |
| description | derived from surface pressure and pressure difference between retrieval levels (the pressure grid is equidistant between the surface pressure and a fixed top pressure); given a zero-based layer index k, the pressure bounds for layer k are derived as: (surface_pressure - k * pressure_interval, surface_pressure - (k + 1) * pressure_interval); the vertical grid is inverted to make it ascending | |
| surface_altitude | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude[] |
| surface_altitude_uncertainty | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude_precision[] |
| surface_pressure | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_pressure[] |
| CH4_column_volume_mixing_ratio_dry_air | condition | ch4 unset |
| path | /PRODUCT/methane_mixing_ratio[] | |
| condition | ch4=bias_corrected | |
| path | /PRODUCT/methane_mixing_ratio_bias_corrected[] | |
| CH4_column_volume_mixing_ratio_dry_air_uncertainty | path | /PRODUCT/methane_mixing_ratio_precision[] |
| CH4_column_volume_mixing_ratio_dry_air_validity | path | /PRODUCT/qa_value |
| CH4_column_volume_mixing_ratio_dry_air_avk | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/column_averaging_kernel[] |
| description | the vertical grid is inverted to make it ascending | |
| CH4_column_number_density_apriori | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/methane_profile_apriori[] |
| description | the vertical grid is inverted to make it ascending | |
| dry_air_column_number_density | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/dry_air_subcolumns[] |
| 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_fraction | path | /PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_fraction_VIIRS_SWIR_IFOV[] |
| aerosol_height | condition | processor version >= 01.00.00 |
| path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/aerosol_mid_altitude[] | |
| condition | processor version < 01.00.00 | |
| path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/aerosol_mid_height[] | |
| aerosol_optical_depth | path | /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/aerosol_optical_thickness_SWIR[] |