# GEOMS-TE-FTIR-002-CH4

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of GEOMS-TE-FTIR-002-CH4 data.

field name

type

dimensions

unit

description

sensor_name

string

name of the sensor

location_name

string

name of the site at which the sensor is located

measurement_mode

string

‘solar’ or ‘lunar’ measurement

sensor_latitude

double

[degree_north]

latitude of the sensor

sensor_longitude

double

[degree_east]

longitude of the sensor

sensor_altitude

double

[km]

altitude of the sensor

datetime

double

{time}

[days since 2000-01-01]

time of the measurement

datetime_length

double

{time}

[s]

duration of the measurement

CH4_column_number_density

double

{time}

[molec/m2]

total CH4 vertical column

CH4_column_number_density_apriori

double

{time}

[molec/m2]

a priori total CH4 vertical column

CH4_column_number_density_avk

double

{time, vertical}

[]

averaging kernel for the total CH4 vertical column

CH4_column_number_density_uncertainty_random

double

{time}

[molec/m2]

random uncertainty of the total CH4 vertical column

CH4_column_number_density_uncertainty_systematic

double

{time}

[molec/m2]

systematic uncertainty of the total CH4 vertical column

H2O_column_number_density

double

{time}

[molec/m2]

total H2O vertical column

CH4_volume_mixing_ratio

double

{time, vertical}

[ppmv]

CH4 volume mixing ratio

CH4_volume_mixing_ratio_apriori

double

{time, vertical}

[ppmv]

a priori CH4 volume mixing ratio

CH4_volume_mixing_ratio_avk

double

{time, vertical, vertical}

[]

averaging kernel for the CH4 volume mixing ratio

CH4_volume_mixing_ratio_covariance

double

{time, vertical, vertical}

[(ppmv)2]

covariance of the CH4 volume mixing ratio

CH4_volume_mixing_ratio_uncertainty_random

double

{time, vertical}

[ppmv]

random uncertainty of the CH4 volume mixing ratio

CH4_volume_mixing_ratio_uncertainty_systematic

double

{time, vertical}

[ppmv]

systematic uncertainty of the CH4 volume mixing ratio

H2O_volume_mixing_ratio

double

{time, vertical}

[ppmv]

H2O volume mixing ratio

altitude

double

{time, vertical}

[km]

retrieval effective altitude

altitude_bounds

double

{time, vertical, 2}

[km]

lower and upper boundaries of the height layers

pressure

double

{time, vertical}

[hPa]

independent pressure profile

temperature

double

{time, vertical}

[K]

independent temperature profile

surface_pressure

double

{time}

[hPa]

independent surface pressure

surface_temperature

double

{time}

[K]

independent surface temperature

solar_azimuth_angle

double

{time}

[degree]

solar azimuth angle

solar_zenith_angle

double

{time}

[degree]

solar zenith angle

index

int32

{time}

zero-based index of the sample within the source product

## Mapping description

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

field name

mapping description

sensor_name

path

/@DATA.SOURCE

location_name

path

/@DATA.LOCATION

measurement_mode

condition

determined from ‘variable mode’ part of variable names

sensor_latitude

path

/LATITUDE.INSTRUMENT

sensor_longitude

path

/LONGITUDE.INSTRUMENT

sensor_altitude

path

/ALTITUDE.INSTRUMENT

datetime

path

/DATETIME

datetime_length

available

optional

path

/INTEGRATION.TIME

CH4_column_number_density

condition

solar measurement

path

/CH4.COLUMN_ABSORPTION.SOLAR

description

unit is converted to molec/m2

condition

lunar measurement

path

/CH4.COLUMN_ABSORPTION.LUNAR

description

unit is converted to molec/m2

CH4_column_number_density_apriori

condition

solar measurement

path

/CH4.COLUMN_ABSORPTION.SOLAR_APRIORI

description

unit is converted to molec/m2

condition

lunar measurement

path

/CH4.COLUMN_ABSORPTION.LUNAR_APRIORI

description

unit is converted to molec/m2

CH4_column_number_density_avk

condition

solar measurement

path

/CH4.COLUMN_ABSORPTION.SOLAR_AVK

description

the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

/CH4.COLUMN_ABSORPTION.LUNAR_AVK

description

the vertical axis is re-ordered from surface to top-of-atmosphere

CH4_column_number_density_uncertainty_random

condition

solar measurement

path

/CH4.COLUMN_ABSORPTION.SOLAR_UNCERTAINTY.RANDOM.STANDARD

description

unit is converted to molec/m2

condition

lunar measurement

path

/CH4.COLUMN_ABSORPTION.LUNAR_UNCERTAINTY.RANDOM.STANDARD

description

unit is converted to molec/m2

CH4_column_number_density_uncertainty_systematic

condition

solar measurement

path

/CH4.COLUMN_ABSORPTION.SOLAR_UNCERTAINTY.SYSTEMATIC.STANDARD

description

unit is converted to molec/m2

condition

lunar measurement

path

/CH4.COLUMN_ABSORPTION.LUNAR_UNCERTAINTY.SYSTEMATIC.STANDARD

description

unit is converted to molec/m2

H2O_column_number_density

condition

solar measurement

path

/H2O.COLUMN_ABSORPTION.SOLAR

description

unit is converted to molec/m2

condition

lunar measurement

path

/H2O.COLUMN_ABSORPTION.LUNAR

description

unit is converted to molec/m2

CH4_volume_mixing_ratio

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

CH4_volume_mixing_ratio_apriori

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR_APRIORI

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR_APRIORI

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

CH4_volume_mixing_ratio_avk

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR_AVK

description

the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR_AVK

description

the vertical axis is re-ordered from surface to top-of-atmosphere

CH4_volume_mixing_ratio_covariance

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR_UNCERTAINTY.RANDOM.COVARIANCE

description

unit is converted to (ppmv)2; the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR_UNCERTAINTY.RANDOM.COVARIANCE

description

unit is converted to (ppmv)2; the vertical axis is re-ordered from surface to top-of-atmosphere

CH4_volume_mixing_ratio_uncertainty_random

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR_UNCERTAINTY.RANDOM.COVARIANCE

description

the vertical axis is re-ordered from surface to top-of-atmosphere; the uncertainty is the square root of the trace of the covariance; unit is converted to ppmv

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR_UNCERTAINTY.RANDOM.COVARIANCE

description

the vertical axis is re-ordered from surface to top-of-atmosphere; the uncertainty is the square root of the trace of the covariance; unit is converted to ppmv

CH4_volume_mixing_ratio_uncertainty_systematic

available

optional

condition

solar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR_UNCERTAINTY.SYSTEMATIC.COVARIANCE

description

the vertical axis is re-ordered from surface to top-of-atmosphere; the uncertainty is the square root of the trace of the covariance; unit is converted to ppmv

condition

lunar measurement

path

/CH4.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR_UNCERTAINTY.SYSTEMATIC.COVARIANCE

description

the vertical axis is re-ordered from surface to top-of-atmosphere; the uncertainty is the square root of the trace of the covariance; unit is converted to ppmv

H2O_volume_mixing_ratio

condition

solar measurement

path

/H2O.MIXING.RATIO.VOLUME_ABSORPTION.SOLAR

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

condition

lunar measurement

path

H2O.MIXING.RATIO.VOLUME_ABSORPTION.LUNAR

description

unit is converted to ppmv; the vertical axis is re-ordered from surface to top-of-atmosphere

altitude

path

/ALTITUDE

description

the vertical axis is re-ordered from surface to top-of-atmosphere

altitude_bounds

path

/ALTITUDE.BOUNDS

description

lower and upper boundaries of the height layers

pressure

path

/PRESSURE_INDEPENDENT

description

independent pressure profile

temperature

path

/TEMPERATURE_INDEPENDENT

description

independent temperature profile

surface_pressure

path

/SURFACE.PRESSURE_INDEPENDENT

surface_temperature

path

/SURFACE.TEMPERATURE_INDEPENDENT

solar_azimuth_angle

condition

solar measurement

path

/ANGLE.SOLAR_AZIMUTH

condition

lunar measurement

path

/ANGLE.LUNAR_AZIMUTH

solar_zenith_angle

condition

solar measurement

path

/ANGLE.SOLAR_ZENITH.ASTRONOMICAL

condition

lunar measurement

path

/ANGLE.LUNAR_ZENITH.ASTRONOMICAL