QA4ECV_L2_HCHO

Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of QA4ECV_L2_HCHO 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)

tropospheric_HCHO_column_number_density

float

{time}

[molec/cm^2]

tropospheric vertical column of HCHO

tropospheric_HCHO_column_number_density_uncertainty_random

float

{time}

[molec/cm^2]

uncertainty of the tropospheric vertical column of HCHO due to random effects

tropospheric_HCHO_column_number_density_uncertainty_systematic

float

{time}

[molec/cm^2]

uncertainty of the tropospheric vertical column of HCHO due to systematic effects

tropospheric_HCHO_column_number_density_amf

float

{time}

[]

tropospheric air mass factor

HCHO_column_number_density_avk

float

{time, vertical}

[]

averaging kernel for the total column number density of tropospheric HCHO

HCHO_volume_mixing_ratio_dry_air_apriori

float

{time, vertical}

[ppv]

apriori profile for the volume mixing ratio of tropospheric HCHO

surface_albedo

float

{time}

[]

surface albedo in the HCHO 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_HCHO products.

option name

legal values

description

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_hcho[]

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

tropospheric_HCHO_column_number_density

path

/PRODUCT/tropospheric_hcho_vertical_column[]

tropospheric_HCHO_column_number_density_uncertainty_random

path

/PRODUCT/tropospheric_hcho_vertical_column_uncertainty_random[]

tropospheric_HCHO_column_number_density_uncertainty_systematic

path

/PRODUCT/tropospheric_hcho_vertical_column_uncertainty_systematic[]

tropospheric_HCHO_column_number_density_amf

path

/PRODUCT/amf_trop[]

HCHO_column_number_density_avk

path

/PRODUCT/averaging_kernel[]

HCHO_volume_mixing_ratio_dry_air_apriori

path

/PRODUCT/SUPPORT_DATA/INPUT_DATA/hcho_profile_apriori[]

surface_albedo

path

/PRODUCT/SUPPORT_DATA/INPUT_DATA/surface_albedo_hcho[]

validity

path

/PRODUCT/SUPPORT_DATA/DETAILED_RESULTS/processing_quality_flags[]