# ECA_ATL_AER_2A

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `ECA_ATL_AER_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
orbit_index | int32 |  |  | absolute orbit number
altitude | float | {time, vertical} | [m] | joint standard grid height
surface_altitude | float | {time} | [m] | surface altitude
particle_extinction_coefficient | float | {time, vertical} | [1/m] | particle extinction coefficient 355nm
particle_extinction_coefficient_uncertainty | float | {time, vertical} | [1/m] | particle extinction coefficient 355nm error
particle_backscatter_coefficient | float | {time, vertical} | [1/m/sr] | particle backscatter coefficient 355nm
particle_backscatter_coefficient_uncertainty | float | {time, vertical} | [1/m/sr] | particle backscatter coefficient 355nm error
particle_linear_depolarization_ratio | float | {time, vertical} | [] | particle linear depolarization ratio 355nm
particle_linear_depolarization_ratio_uncertainty | float | {time, vertical} | [] | particle linear depolarization ratio 355nm error
lidar_ratio | float | {time, vertical} | [sr] | lidar ratio 355nm
lidar_ratio_uncertainty | float | {time, vertical} | [sr] | lidar ratio 355nm error
tropopause_height | float | {time} | [m] | tropopause height
aerosol_type | int8 | {time, vertical} |  | aerosol classification
scene_type | int8 | {time, vertical} |  | classification
validity | int8 | {time, vertical} |  | quality status
wavelength | float |  | [nm] | lidar wavelength
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
--- | ---
datetime | path | /ScienceData/time
latitude | path | /ScienceData/latitude
longitude | path | /ScienceData/longitude
orbit_index | path | /HeaderData/VariableProductHeader/MainProductHeader/orbitNumber
altitude | path | /ScienceData/height, /ScienceData/geoid_offset
description | the vertical grid is inverted to make it ascending; altitude[i,j] = height[i,j] - geoid_offset[i]
surface_altitude | path | /ScienceData/elevation, /ScienceData/geoid_offset
description | altitude = elevation - geoid_offset
particle_extinction_coefficient | path | /ScienceData/particle_extinction_coefficient_355nm
description | the vertical grid is inverted to make it ascending
particle_extinction_coefficient_uncertainty | path | /ScienceData/particle_extinction_coefficient_355nm_error
description | the vertical grid is inverted to make it ascending
particle_backscatter_coefficient | path | /ScienceData/particle_backscatter_coefficient_355nm
description | the vertical grid is inverted to make it ascending
particle_backscatter_coefficient_uncertainty | path | /ScienceData/particle_backscatter_coefficient_355nm_error
description | the vertical grid is inverted to make it ascending
particle_linear_depolarization_ratio | path | /ScienceData/particle_linear_depol_ratio_355nm
description | the vertical grid is inverted to make it ascending
particle_linear_depolarization_ratio_uncertainty | path | /ScienceData/particle_linear_depol_ratio_355nm_error
description | the vertical grid is inverted to make it ascending
lidar_ratio | path | /ScienceData/lidar_ratio_355nm
description | the vertical grid is inverted to make it ascending
lidar_ratio_uncertainty | path | /ScienceData/lidar_ratio_355nm_error
description | the vertical grid is inverted to make it ascending
tropopause_height | path | /ScienceData/tropopause_height
aerosol_type | path | /ScienceData/aerosol_classification
description | the vertical grid is inverted to make it ascending
scene_type | path | /ScienceData/classification
description | the vertical grid is inverted to make it ascending
validity | path | /ScienceData/quality_status
description | the vertical grid is inverted to make it ascending
wavelength | description | set to fixed value of 355nm