# MLS_L2_CH3OH

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `MLS_L2_CH3OH` 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
pressure | double | {vertical} | [hPa] | pressure per profile level
CH3OH_volume_mixing_ratio | double | {time, vertical} | [ppv] | CH3OH volume mixing ratio
CH3OH_volume_mixing_ratio_uncertainty | double | {time, vertical} | [ppv] | uncertainty of the CH3OH volume mixing ratio
CH3OH_volume_mixing_ratio_validity | int32 | {time, vertical} |  | quality flag for the CH3OH volume mixing ratio
index | int32 | {time} |  | zero-based index of the sample within the source product

## Mapping description

Bits 4 to 9 and 11 to 14 in the quality flag denote a specific error condition while bits 0 to 2 denote the severity (bit 0 error, bit 1 warning, bit 2 comment).

Bits 4 to 9 denote the MLS status (bit 4 HICLOUD, bit 5 LOWCLOUD, bit 6 NO_APRIORI_T, bit 7 NUM_ERROR, bit 8 TOO_FEW_RAD, bit 9 GLOB_FAILURE).

Bits 11 to 14 denote specific checks as specified in the EOS MLS data quality document (the pressure range, quality and convergence thresholds come from table 1.1.1 in issue 4.2 of that document): Bit 11 denotes pressure out of range, bit 12 denotes quality below threshold, bit 13 denotes convergence above threshold and bit 14 denotes a negative precision. Also, if any of the bits 11 to 14 is set, bit 0 is automatically set.

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

field name | mapping description
--- | ---
datetime | path | /HDFEOS/SWATHS/CH3OH/Geolocation_Fields/Time[]
description | the time converted from TAI93 to seconds since 2000-01-01T00:00:00
longitude | path | /HDFEOS/SWATHS/CH3OH/Geolocation_Fields/Longitude[]
latitude | path | /HDFEOS/SWATHS/CH3OH/Geolocation_Fields/Latitude[]
pressure | path | /HDFEOS/SWATHS/CH3OH/Geolocation_Fields/Pressure[]
CH3OH_volume_mixing_ratio | path | /HDFEOS/SWATHS/CH3OH/Data_Fields/L2gpValue[]
CH3OH_volume_mixing_ratio_uncertainty | path | /HDFEOS/SWATHS/CH3OH/Data_Fields/L2gpPrecision[]
CH3OH_volume_mixing_ratio_validity | path | /HDFEOS/SWATHS/CH3OH/Data_Fields/Status[]