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 |
surface_meridional_wind_velocity |
float |
{time} |
[m/s] |
northward wind |
surface_zonal_wind_velocity |
float |
{time} |
[m/s] |
eastward wind |
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 100 (full quality data) |
|
CH4_column_number_density_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 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 |
surface_albedo |
float |
{time} |
[] |
surface albedo |
surface_albedo_uncertainty |
float |
{time} |
[] |
precision of the surface albedo |
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_CH4 products.
option name |
legal values |
description |
|---|---|---|
ch4 |
bias_corrected, corrected |
whether to ingest the ‘normal’ CH4 column vmr (default) or the bias corrected CH4 column vmr (ch4=bias_corrected), or the bias corrected and destriping corrected CH4 column vmr (ch4=corrected) |
band |
NIR |
whether to retrieve aerosol/cloud/surface properties of the TROPOMI SWIR band (default) or the NIR band (band=NIR) |
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[] |
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[] |
|
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[] |
|
condition |
ch4=corrected and processor version >= 02.07.00 |
|
path |
/PRODUCT/methane_mixing_ratio_bias_corrected_destriped[] |
|
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_number_density_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 |
condition |
band=NIR |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_fraction_VIIRS_NIR_IFOV[] |
|
condition |
band unset |
|
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 |
condition |
band=NIR |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/aerosol_optical_thickness_NIR[] |
|
condition |
band unset |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/aerosol_optical_thickness_SWIR[] |
|
surface_albedo |
condition |
band=NIR |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/surface_albedo_NIR[] |
|
condition |
band unset |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/surface_albedo_SWIR[] |
|
surface_albedo_uncertainty |
condition |
band=NIR |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/surface_albedo_NIR_precision[] |
|
condition |
band unset |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/surface_albedo_SWIR_precision[] |
|
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 |
|