# ECA_AM__CTH_2B

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `ECA_AM__CTH_2B` 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
cloud_fraction | float | {time} | [] | cloud fraction
cloud_top_height | float | {time} | [m] | cloud top height
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_AM__CTH_2B` products.

option name | legal values | description
--- | --- | ---
source | atlid | whether to ingest the cloud top height from MSI (default) or ATLID (data=atlid)

## 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
cloud_fraction | path | /ScienceData/cloud_fraction
cloud_top_height | condition | source unset
path | /ScienceData/cloud_top_height_MSI, /ScienceData/geoid_offset
description | cloud_top_height_MSI - geoid_offset
condition | source=atlid
path | /ScienceData/cloud_top_height_MSI, /ScienceData/cloud_top_height_difference_ATLID_MSI, /ScienceData/geoid_offset
description | cloud_top_height_MSI + cloud_top_height_difference_ATLID_MSI - geoid_offset
validity | path | /ScienceData/quality_status