IAS_02_TWV — HARP 1.29 documentation

# IAS_02_TWV

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of `IAS_02_TWV` data.

field name | type | dimensions | unit | description
--- | --- | --- | --- | ---
orbit_index | int32 |  |  | absolute orbit number
datetime | double | {time} | [s since 2020-01-01] | on-board time in UTC
longitude | double | {time} | [degree_east] | geocentric longitude at sounder pixel centre
longitude_bounds | double | {time, 4} | [degree_east] | corner longitudes of the measurement
latitude | double | {time} | [degree_north] | geodetic latitude at sounder pixel centre
latitude_bounds | double | {time, 4} | [degree_north] | corner latitudes of the measurement
solar_azimuth_angle | double | {time} | [degree] | solar azimuth angle at sounder pixel centre
solar_zenith_angle | double | {time} | [degree] | solar zenith angle at sounder pixel centre
sensor_azimuth_angle | double | {time} | [degree] | measurement azimuth angle at sounder pixel centre
sensor_zenith_angle | double | {time} | [degree] | measurement zenith angle at sounder pixel centre
ice_fraction | float | {time} | [] | fraction of IFOV covered by sea ice
land_fraction | float | {time} | [] | land fraction
surface_altitude | float | {time} | [m] | surface elevation
surface_altitude_uncertainty | float | {time} | [m] | standard deviation of surface elevation
water_vapor_column_density | float | {time} | [kg/m2] | integrated water vapor
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
--- | ---
orbit_index | path | /@orbit_start
datetime | path | /data/geolocation_information/onboard_utc[]
longitude | path | /data/geolocation_information/sounder_pixel_longitude[]
longitude_bounds | path | /data/geolocation_information/sounder_pixel_longitude_bounds[]
description | the corner coordinates are rough estimates of the circle areas for the scan elements; the size of a scan element (in a certain direction) is taken to be half the distance, from center to center, from a scan element to its nearest neighboring scan element (within the same 2x2 subgrid inside a Field of Regard (FOR))
latitude | path | /data/geolocation_information/sounder_pixel_latitude[]
latitude_bounds | path | /data/geolocation_information/sounder_pixel_latitude_bounds[]
description | the corner coordinates are rough estimates of the circle areas for the scan elements; the size of a scan element (in a certain direction) is taken to be half the distance, from center to center, from a scan element to its nearest neighboring scan element (within the same 2x2 subgrid inside a Field of Regard (FOR))
solar_azimuth_angle | path | /data/geolocation_information/sounder_pixel_sun_azimuth[]
solar_zenith_angle | path | /data/geolocation_information/sounder_pixel_sun_zenith[]
sensor_azimuth_angle | path | /data/geolocation_information/sounder_pixel_azimuth[]
sensor_zenith_angle | path | /data/geolocation_information/sounder_pixel_zenith[]
ice_fraction | path | /data/surface_info/ice_fraction[]
land_fraction | path | /data/surface_info/land_fraction[]
surface_altitude | path | /data/surface_info/height[]
surface_altitude_uncertainty | path | /data/surface_info/height_std[]
water_vapor_column_density | path | /data/optimal_estimation/atmosphere_mass_content_of_water[]