# ECA_MSI_AOT_2A

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `ECA_MSI_AOT_2A` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
datetime | double | {time} | [seconds since 2000-01-01] | UTC time
latitude | double | {time} | [degree_north] | Geodetic latitude
longitude | double | {time} | [degree_east] | Geodetic longitude
latitude_bounds | double | {time, 4} | [degree_north] | latitudes of the ground pixel corners (WGS84)
longitude_bounds | double | {time, 4} | [degree_east] | longitudes of the ground pixel corners (WGS84)
orbit_index | int32 |  |  | absolute orbit number
aerosol_optical_depth | float | {time} | [] | aerosol optical thickness
aerosol_optical_depth_uncertainty | float | {time} | [] | aerosol optical thickness error
angstrom_exponent | float | {time} | [] | angstrom parameter
surface_reflectance | float | {time} | [] | surface reflectance
surface_reflectance_uncertainty | float | {time} | [] | surface reflectance error
validity | int8 | {time} |  | quality status
index | int32 | {time} |  | zero-based index of the sample within the source product

## Ingestion options

The table below lists the available ingestion options for `ECA_MSI_AOT_2A` products.

option name | legal values | description
--- | --- | ---
angstrom | 670/865 | wavelength combination for which the angstrom exponent is extracted: 355/670 (default), or 670/865 (angstrom=670/865)
aot | 865 | wavelength for which to ingest the aerosol optical thickness: 670nm (default) or 865nm (aot=865)

## Mapping description

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

field name | mapping description
--- | ---
datetime | path | /ScienceData/time
description | time is replicated in the across track dimension
latitude | path | /ScienceData/latitude
longitude | path | /ScienceData/longitude
latitude_bounds | description | interpolated from the center coordinates for each of the ground pixels
longitude_bounds | description | interpolated from the center coordinates for each of the ground pixels
orbit_index | path | /HeaderData/VariableProductHeader/MainProductHeader/orbitNumber
aerosol_optical_depth | condition | aot unset
path | /ScienceData/aerosol_optical_thickness_670nm
condition | aot=865
path | /ScienceData/aerosol_optical_thickness_865nm
aerosol_optical_depth_uncertainty | condition | aot unset
path | /ScienceData/aerosol_optical_thickness_670nm_error
condition | aot=865
path | /ScienceData/aerosol_optical_thickness_865nm_error
angstrom_exponent | condition | angstrom unset
path | /ScienceData/angstrom_parameter_355nm_670nm
condition | angstrom=670/865
path | /ScienceData/angstrom_parameter_670nm_865nm
surface_reflectance | available | optional
condition | aot unset
path | /ScienceData/surface_reflectance_670nm
surface_reflectance_uncertainty | available | optional
condition | aot unset
path | /ScienceData/surface_reflectance_670nm_error
validity | path | /ScienceData/quality_status