QA4ECV_L2_NO2
Variables
The table below lists the variables that are present in the HARP product that results from an ingestion of QA4ECV_L2_NO2 data.
field name |
type |
dimensions |
unit |
description |
|---|---|---|---|---|
scan_subindex |
int16 |
{time} |
pixel index (0-based) within the scanline |
|
datetime |
double |
{time} |
[seconds since 1995-01-01] |
start time of the measurement |
orbit_index |
int32 |
absolute orbit number |
||
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) |
solar_zenith_angle |
float |
{time} |
[degree] |
zenith angle of the Sun at the ground pixel location (WGS84); angle measured away from the vertical |
relative_azimuth_angle |
float |
{time} |
[degree] |
relative azimuth angle 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 |
surface_altitude |
float |
{time} |
[m] |
surface altitude |
surface_pressure |
float |
{time} |
[hPa] |
surface pressure |
pressure_bounds |
double |
{time, vertical, 2} |
[Pa] |
pressure boundaries for each layer |
cloud_fraction |
float |
{time} |
[] |
cloud fraction |
cloud_fraction_uncertainty |
float |
{time} |
[] |
effective cloud fraction uncertainty |
cloud_pressure |
float |
{time} |
[hPa] |
cloud optical centroid pressure from the cloud product |
cloud_pressure_uncertainty |
float |
{time} |
[hPa] |
cloud optical centroid pressure from the cloud product |
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) |
tropopause_pressure |
double |
{time} |
[Pa] |
tropopause pressure |
tropospheric_NO2_column_number_density |
float |
{time} |
[molec/cm^2] |
tropospheric vertical column of NO2 |
tropospheric_NO2_column_number_density_uncertainty |
float |
{time} |
[molec/cm^2] |
uncertainty of the tropospheric vertical column of NO2 (standard error) |
tropospheric_NO2_column_number_density_avk |
float |
{time, vertical} |
[] |
averaging kernel for the tropospheric vertical column number density of NO2 |
tropospheric_NO2_column_number_density_amf |
float |
{time} |
[] |
tropospheric air mass factor, computed by integrating the altitude dependent air mass factor over the atmospheric layers from the surface up to and including the layer with the tropopause |
stratospheric_NO2_column_number_density |
float |
{time} |
[molec/cm^2] |
stratospheric vertical column of NO2 |
stratospheric_NO2_column_number_density_uncertainty |
float |
{time} |
[molec/cm^2] |
uncertainty of the stratospheric vertical column of NO2 (standard error) |
stratospheric_NO2_column_number_density_avk |
float |
{time, vertical} |
[] |
averaging kernel for the stratospheric vertical column number density of NO2 |
stratospheric_NO2_column_number_density_amf |
float |
{time} |
[] |
stratospheric air mass factor |
NO2_column_number_density |
float |
{time} |
[molec/cm^2] |
total vertical column of NO2 (ratio of the slant column density of NO2 and the total air mass factor) |
NO2_column_number_density_uncertainty |
float |
{time} |
[molec/cm^2] |
uncertainty of the total vertical column of NO2 (standard error) |
NO2_column_number_density_amf |
float |
{time} |
[] |
total air mass factor, computed by integrating the altitude dependent air mass factor over the atmospheric layers from the surface to top-of-atmosphere |
NO2_column_number_density_avk |
float |
{time, vertical} |
[] |
averaging kernel for the total column number density of NO2 |
surface_albedo |
float |
{time} |
[] |
surface albedo in the NO2 fitting window |
validity |
int32 |
{time} |
processing quality flag |
|
index |
int32 |
{time} |
zero-based index of the sample within the source product |
Ingestion options
The table below lists the available ingestion options for QA4ECV_L2_NO2 products.
option name |
legal values |
description |
|---|---|---|
total_column |
summed, total |
whether to use total_no2_vertical_column (which is derived from the total slant column diveded by the total amf) or summed_no2_total_vertical_column (which is the sum of the retrieved tropospheric and stratospheric columns); option values are ‘summed’ (default) and ‘total’ |
stratospheric_column |
stream |
whether to use the default NO2 stratospheric column (default) or the stratospheric column estimated with the STREAM method (stratospheric_column=stream) |
cloud_fraction |
radiance |
whether to ingest the cloud fraction (default) or the radiance cloud fraction (cloud_fraction=radiance) |
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 |
path |
/PRODUCT/time, /PRODUCT/delta_time[] |
description |
time converted from milliseconds since a reference time (with the reference time being 1995-01-01) to seconds since 1995-01-01; the time associated with a scanline is repeated for each pixel in the scanline |
|
orbit_index |
path |
/@orbit |
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[] |
solar_zenith_angle |
path |
/PRODUCT/SUPPORT_DATA/GEOLOCATIONS/solar_zenith_angle[] |
relative_azimuth_angle |
path |
/PRODUCT/SUPPORT_DATA/GEOLOCATIONS/relative_azimuth_angle[] |
sensor_zenith_angle |
path |
/PRODUCT/SUPPORT_DATA/GEOLOCATIONS/viewing_zenith_angle[] |
surface_altitude |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_altitude[] |
surface_pressure |
path |
/PRODUCT/tm5_surface_pressure[] |
pressure_bounds |
path |
/PRODUCT/tm5_pressure_level_a[], /PRODUCT/tm5_pressure_level_b[], /PRODUCT/tm5_surface_pressure[] |
description |
pressure in Pa at level k is derived from surface pressure in hPa as: tm5_pressure_level_a[k] + tm5_pressure_level_b[k] * tm5_surface_pressure[] * 100.0; the TOA pressure is clamped to 1e-3 Pa |
|
cloud_fraction |
condition |
cloud_fraction unset |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_fraction[] |
|
condition |
cloud_fraction=radiance |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/cloud_radiance_fraction_no2[] |
|
cloud_fraction_uncertainty |
available |
optional |
condition |
cloud_fraction unset |
|
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_fraction_uncertainty[] |
|
cloud_pressure |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_pressure[] |
cloud_pressure_uncertainty |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/cloud_pressure_uncertainty[] |
snow_ice_type |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/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 |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/snow_ice_flag[] |
description |
if 1 <= snow_ice_flag <= 100 then snow_ice_flag/100.0 else 0.0 |
|
tropopause_pressure |
path |
/PRODUCT/tm5_pressure_level_a[], /PRODUCT/tm5_pressure_level_b[], /PRODUCT/tm5_surface_pressure[], /PRODUCT/tm5_tropopause_layer_index[] |
description |
pressure in Pa at tropause is derived from the upper bound of the layer with tropopause layer index k: tm5_pressure_level_a[k + 1] + tm5_pressure_level_b[k + 1] * tm5_surface_pressure[] * 100.0 |
|
tropospheric_NO2_column_number_density |
path |
/PRODUCT/tropospheric_no2_vertical_column[] |
tropospheric_NO2_column_number_density_uncertainty |
path |
/PRODUCT/tropospheric_no2_vertical_column_uncertainty[] |
tropospheric_NO2_column_number_density_avk |
path |
/PRODUCT/averaging_kernel[], /PRODUCT/amf_total[], /PRODUCT/amf_trop[], /PRODUCT/tm5_tropopause_layer_index[] |
description |
averaging_kernel[layer] = if layer <= tm5_tropopause_layer_index then averaging_kernel[layer] * amf_total / amf_trop else 0 |
|
tropospheric_NO2_column_number_density_amf |
path |
/PRODUCT/amf_trop[] |
stratospheric_NO2_column_number_density |
condition |
stratospheric_column unset |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/stratospheric_no2_vertical_column[] |
|
condition |
stratospheric_column=stream |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/stratospheric_no2_vertical_column_stream[] |
|
stratospheric_NO2_column_number_density_uncertainty |
condition |
stratospheric_column unset |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/stratospheric_no2_vertical_column_uncertainty[] |
|
condition |
stratospheric_column=stream |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/stratospheric_no2_vertical_column_stream_uncertainty[] |
|
stratospheric_NO2_column_number_density_avk |
path |
/PRODUCT/averaging_kernel[], /PRODUCT/amf_total[], /PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/amf_strat[], /PRODUCT/tm5_tropopause_layer_index[] |
description |
averaging_kernel[layer] = if layer > tm5_tropopause_layer_index then averaging_kernel[layer] * amf_total / amf_strat else 0 |
|
stratospheric_NO2_column_number_density_amf |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/amf_strat[] |
NO2_column_number_density |
condition |
total_column=summed or total_column unset |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/summed_no2_total_vertical_column[] |
|
condition |
total_column=total |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/total_no2_vertical_column[] |
|
NO2_column_number_density_uncertainty |
condition |
total_column=summed or total_column unset |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/summed_no2_total_vertical_column_uncertainty[] |
|
condition |
total_column=total |
|
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/total_no2_vertical_column_uncertainty[] |
|
NO2_column_number_density_amf |
path |
/PRODUCT/amf_total[] |
NO2_column_number_density_avk |
path |
/PRODUCT/averaging_kernel[] |
surface_albedo |
path |
/PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_albedo_no2[] |
validity |
path |
/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/processing_quality_flags[] |