# OMI_L3_OMTO3d

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `OMI_L3_OMTO3d` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
datetime_start | double | {time} | [seconds since 2000-01-01] | start time of the grid
datetime_length | double | {time} | [days] | length of the grid
longitude | double | {longitude} | [degree_east] | longitude of the grid cell mid-point (WGS84)
latitude | double | {latitude} | [degree_north] | latitude of the grid cell mid-point (WGS84)
O3_column_number_density | double | {time, latitude, longitude} | [DU] | O3 column number density
cloud_fraction | double | {time, latitude, longitude} | [] | cloud fraction
uv_aerosol_index | double | {time, latitude, longitude} | [] | UV aerosol index
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_start | path | /HDFEOS/ADDITIONAL/FILE_ATTRIBUTES@TAI93At0zOfGranule
description | the time of the measurement converted from TAI93 to seconds since 2000-01-01T00:00:00
datetime_length | description | set to fixed value of 1
longitude | path | /HDFEOS/GRIDS/OMI_Column_Amount_O3@GridSpacing, /HDFEOS/GRIDS/OMI_Column_Amount_O3@NumberOfLongitudesInGrid
description | a uniformly increasing sequence on the interval (-180, 180)
latitude | path | /HDFEOS/GRIDS/OMI_Column_Amount_O3@GridSpacing, /HDFEOS/GRIDS/OMI_Column_Amount_O3@NumberOfLatitudesInGrid
description | a uniformly increasing sequence on the interval (-90, 90)
O3_column_number_density | path | /HDFEOS/GRIDS/OMI_Column_Amount_O3/Data_Fields/ColumnAmountO3[]
cloud_fraction | path | /HDFEOS/GRIDS/OMI_Column_Amount_O3/Data_Fields/RadiativeCloudFraction[]
uv_aerosol_index | path | /HDFEOS/GRIDS/OMI_Column_Amount_O3/Data_Fields/UVAerosolIndex[]