# TES_L2_CH4_Nadir

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `TES_L2_CH4_Nadir` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
datetime | double | {time} | [seconds since 2000-01-01] | time of the measurement
longitude | double | {time} | [degree_east] | tangent longitude
latitude | double | {time} | [degree_north] | tangent latitude
altitude | double | {time, vertical} | [m] | altitude per profile level
pressure | double | {time, vertical} | [hPa] | pressure per profile level
CH4_volume_mixing_ratio | double | {time, vertical} | [ppv] | methane volume mixing ratio
CH4_volume_mixing_ratio_uncertainty | double | {time, vertical} | [ppv] | methane volume mixing ratio precision
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 | /HDFEOS/SWATHS/CH4NadirSwath/Geolocation_Fields/Time[]
description | the time converted from TAI93 to seconds since 2000-01-01T00:00:00
longitude | path | /HDFEOS/SWATHS/CH4NadirSwath/Geolocation_Fields/Longitude[]
latitude | path | /HDFEOS/SWATHS/CH4NadirSwath/Geolocation_Fields/Latitude[]
altitude | path | /HDFEOS/SWATHS/CH4NadirSwath/Data_Fields/Altitude[]
pressure | path | /HDFEOS/SWATHS/CH4NadirSwath/Data_Fields/Pressure[]
CH4_volume_mixing_ratio | path | /HDFEOS/SWATHS/CH4NadirSwath/Data_Fields/CH4[]
CH4_volume_mixing_ratio_uncertainty | path | /HDFEOS/SWATHS/CH4NadirSwath/Data_Fields/CH4Precision[]