# ESACCI_OZONE_L2_NP

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `ESACCI_OZONE_L2_NP` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
scan_subindex | int16 | {time} |  | zero-based index of the instantaneous field of view within the swath
datetime | double | {time} | [hours since 2000-01-01] | time of the measurement
longitude | float | {time} | [degree_east] | longitude of the ground pixel center
latitude | float | {time} | [degree_north] | latitude of the ground pixel center
longitude_bounds | float | {time, 4} | [degree_east] | longitudes of the ground pixel corners
latitude_bounds | float | {time, 4} | [degree_north] | latitudes of the ground pixel corners
sensor_zenith_angle | float | {time} | [degree] | zenith angle of the sensor at the ground pixel center
solar_zenith_angle | float | {time} | [degree] | zenith angle of the Sun at the ground pixel center
pressure | float | {vertical} | [hPa] | pressure
O3_number_density | float | {time, vertical} | [molec/cm3] | O3 number density
O3_number_density_uncertainty | float | {time, vertical} | [molec/cm3] | uncertainty of the O3 number density
O3_number_density_covariance | float | {time, vertical, vertical} | [(molec/cm3)2] | O3 number density solution covariance matrix
O3_number_density_avk | float | {time, vertical, vertical} | [] | O3 number density averaging kernel
O3_volume_mixing_ratio | float | {time, vertical} | [ppv] | O3 volume mixing ratio
O3_volume_mixing_ratio_uncertainty | float | {time, vertical} | [ppv] | uncertainty of the O3 volume mixing ratio
O3_volume_mixing_ratio_apriori | float | {time, vertical} | [ppv] | O3 volume mixing ratio apriori
O3_volume_mixing_ratio_apriori_uncertainty | float | {time, vertical} | [ppv] | uncertainty of the O3 volume mixing ratio apriori
cloud_fraction | double | {time} | [] | effective cloud fraction
cloud_top_pressure | double | {time} | [hPa] | cloud top pressure
cloud_top_albedo | double | {time} | [] | cloud top albedo
surface_albedo | float | {time} | [] | surface albedo
surface_pressure | float | {time} | [hPa] | surface pressure
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
--- | ---
scan_subindex | path | /scp[]
datetime | path | /@Data_date, /time[]
description | datetime converted from the epoch of the product and an offset in hours to hours since 2000-01-01
longitude | path | /lon[]
latitude | path | /lat[]
longitude_bounds | path | /ll[]
description | longitudes and latitudes of the ground pixel corners are stored interleaved; longitudes are ingested as [ll[,1], ll[,3], ll[,7], ll[,5]]; note the reordering of the last two values to ensure a simple polygon
latitude_bounds | path | /ll[]
description | longitudes and latitudes of the ground pixel corners are stored interleaved; latitudes are ingested as [ll[,0], ll[,2], ll[,6], ll[,4]]; note the reordering of the last two values to ensure a simple polygon
sensor_zenith_angle | path | /lza[]
solar_zenith_angle | path | /sza[]
pressure | path | /levs[]
O3_number_density | path | /o3_nd[]
O3_number_density_uncertainty | path | /o3_nd[], /o3_error[]
description | derived from the relative error in percent as: o3_error[] * 0.01 * o3_nd[]
O3_number_density_covariance | path | /sx[]
O3_number_density_avk | path | /ak[]
O3_volume_mixing_ratio | path | /o3_vmr[]
O3_volume_mixing_ratio_uncertainty | path | /o3_vmr[], /o3_error[]
description | derived from the relative error in percent as: o3_error[] * 0.01 * o3_vmr[]
O3_volume_mixing_ratio_apriori | path | /o3_ap[]
O3_volume_mixing_ratio_apriori_uncertainty | path | /o3_ap[], /o3_ap_error[]
description | derived from the relative error in percent as: o3_ap_error[] * 0.01 * o3_ap[]
cloud_fraction | path | /cloudf[]
cloud_top_pressure | path | /cloudp[]
cloud_top_albedo | path | /clouda[]
surface_albedo | path | /salb[]
surface_pressure | path | /spres[]