# SCIAMACHY_L1c_sun_reference

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `SCIAMACHY_L1c_sun_reference` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
wavelength_photon_irradiance | double | {time, spectral} | [(count/s/cm2/nm)] | wavelength photon irradiance of each spectrum measurement
wavelength_photon_irradiance_uncertainty | double | {time, spectral} | [(count/s/cm2/nm)] | error in the wavelength photon radiance of each spectrum measurement
wavelength | double | {time, spectral} | [nm] | nominal wavelength assignment for each of the detector pixels
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_L1c` products.

option name | legal values | description
--- | --- | ---
data | nadir, limb, occultation, sun_reference | retrieve the nadir, limb, occultation or sun_reference spectra; by default the nadir spectra are retrieved

This definition is only applicable when: data=sun_reference

## Mapping description

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

field name | mapping description
--- | ---
wavelength_photon_irradiance | path | /sun_reference[]/mean_ref_spec[], /sun_reference[]/sun_spect_id
description | only the first calibrated diffuser sun spectrum (i.e. whose sun_spect_id starts with ‘D’) is ingested
wavelength_photon_irradiance_uncertainty | path | /sun_reference[]/rad_pre_mean_sun_ref_spec[], /sun_reference[]/sun_spect_id
description | only the first calibrated diffuser sun spectrum (i.e. whose sun_spect_id starts with ‘D’) is ingested
wavelength | path | /sun_reference[]/wvlen_sun_meas[], /sun_reference[]/sun_spect_id
description | only the first calibrated diffuser sun spectrum (i.e. whose sun_spect_id starts with ‘D’) is ingested