# SCIAMACHY_L2_LIMB_UV1_NO2

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of SCIAMACHY_L2_LIMB_UV1_NO2 data.

field name

type

dimensions

unit

description

datetime_start

double

{time}

[seconds since 2000-01-01]

measurement start time for each profile

datetime_length

double

{time}

[s]

measurement integration time

orbit_index

int32

absolute orbit number

altitude_bounds

double

{time, vertical, 2}

[km]

altitude bounds for each profile point

pressure_bounds

double

{time, vertical, 2}

[hPa]

pressure bounds for each profile point

latitude

double

{time}

[degree_north]

tangent latitude of the vertically mid profile point

longitude

double

{time}

[degree_east]

tangent longitude of the vertically mid profile point

solar_zenith_angle

double

{time}

[degree]

solar zenith angle at top of atmosphere for the middle most profile point

viewing_zenith_angle

double

{time}

[degree]

line of sight zenith angle at top of atmosphere for the middle most profile point

relative_azimuth_angle

double

{time}

[degree]

relative azimuth angle at top of atmosphere for the middle most profile point

temperature

double

{time, vertical}

[K]

temperature for each profile point

NO2_volume_mixing_ratio

double

{time, vertical}

[ppv]

NO2 volume mixing ratio

NO2_volume_mixing_ratio_uncertainty

double

{time, vertical}

[ppv]

error on the NO2 volume mixing ratio

NO2_volume_mixing_ratio_avk

double

{time, vertical, vertical}

[]

averaging kernel on the NO2 volume mixing ratio

NO2_number_density

double

{time, vertical}

[molec/cm^3]

NO2 number density

NO2_number_density_uncertainty

double

{time, vertical}

[molec/cm^3]

error on the NO2 number density

NO2_number_density_apriori

double

{time, vertical}

[molec/cm^3]

a priori NO2 number density profile

NO2_number_density_avk

double

{time, vertical, vertical}

[(molec/cm^3)/(molec/cm^3)]

averaging kernel on the NO2 number density

index

int32

{time}

zero-based index of the sample within the source product

## Ingestion options

The table below lists the available ingestion options for SCIAMACHY_L2 products.

option name

legal values

description

dataset

This definition is only applicable when: dataset=lim_uv1_no2

## Mapping description

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

field name

mapping description

datetime_start

path

/geolocation_limb[]/dsr_time

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

datetime_length

path

/lim_uv1_no2[]/integr_time

orbit_index

path

/mph/abs_orbit

altitude_bounds

path

/lim_uv1_no2[]/tangent_height[]

description

the tangent heights are the lower bound altitudes; for the top of the highest layer a TOA value of 100km is used

pressure_bounds

path

/lim_uv1_no2[]/tangent_pressure[]

description

the tangent pressures are the lower bound pressures; for the top of the highest layer a pressure value of 3.2e-4 hPa is used

latitude

path

/geolocation_limb[]/tangent_coord[1]/latitude

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

longitude

path

/geolocation_limb[]/tangent_coord[1]/longitude

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

solar_zenith_angle

path

/geolocation_limb[]/sol_zen_angle_toa[1]

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

viewing_zenith_angle

path

/geolocation_limb[]/los_zen_angle_toa[1]

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

relative_azimuth_angle

path

/geolocation_limb[]/rel_azi_angle_toa[1]

description

records in geolocation_limb do not have a one-to-one mapping with records in the limb/occultation measurement datasets; HARP uses a single measurement time and tangent location per profile which is taken from the middlemost measurement used for the retrieval (i.e. index = (n_meas - 1) / 2); the geolocation record for this measurement is retrieved by matching the measurement time measurement_grid[(n_meas - 1) / 2].dsr_time with the geolocation record time geolocation_limb[]/dsr_time

temperature

path

/lim_uv1_no2[]/tangent_temp[]

NO2_volume_mixing_ratio

path

/lim_uv1_no2[]/main_species[,0]/tang_vmr

NO2_volume_mixing_ratio_uncertainty

path

/lim_uv1_no2[]/main_species[,0]/err_tang_vmr, /lim_uv1_no2[]/main_species[,0]/tang_vmr

description

relative error is converted to absolute error by multiplying with measured value

NO2_volume_mixing_ratio_avk

available

optional

condition

additional diagnostics vector in limb DSR is long enough to contain number density and AKM information

path

description

the AVK for partial columns as given in the add_diag vector at position 2+stvec+2*n1*num_altitudes+2*num_altitudes is converted to volume mixing ratio units by multiplying each element with conv_mix_i/conv_mix_j, where conv_mix is found in add_diag at position 2+stvec+2*n1*num_altitudes; the vertical axis of the AVK are reversed

NO2_number_density

available

optional

condition

additional diagnostics vector in limb DSR is long enough to contain number density and AKM information

path

NO2_number_density_uncertainty

available

optional

condition

additional diagnostics vector in limb DSR is long enough to contain number density and AKM information

path

description

relative error is converted to absolute error by multiplying with measured value

NO2_number_density_apriori

available

optional

condition

additional diagnostics vector in limb DSR is long enough to contain number density and AKM information

path

NO2_number_density_avk

available

optional

condition

additional diagnostics vector in limb DSR is long enough to contain number density and AKM information

path