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Description

This dataset contains model output interpolated in space and time to observations from the MetOp-A ASCAT (ASCAT-A) instrument (a satellite-based scatterometer), representing the first science quality release of these data (post-provisional after v1.0) funded under the MEaAUREs program. These auxiliary fields are included to complement those scatterometer observations, specifically for the ASCATA_ESDR_L2_WIND_STRESS_V1.1 dataset. Model variables include: i) ocean surface wind fields from ERA-5 short-term forecast (removed from the analyses times to reduce impacts from assimilated scatterometer retrievals at the beginning of the forecast); ii) estimations of precipitation from the GPM IMERG product; iii) estimation of the surface currents from the GlobCurrent project. The fields are provided on a non-uniform grid within the sampled locations of the ASCAT-A Level 2 product, and at a nominal 12.5 km pixel resolution. Each file corresponds to a specific orbital revolution number, which begins at the southernmost point of the ascending orbit. The thumbnail shows data for two orbits - using all orbits for a single day will provide global coverage.
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The dataset represents the first science quality release of this product with funding from the MEaSUREs (Making Earth System Data Records for Use in Research Environments) program. Version 1.1 provides a set of updates and improvements from version 1.0, including: 1) cleaned up ancillary data points in between the left/right swaths for improved collocation with available satellite data, 2) improved variable metadata, 3) removed the GlobCurrent stokes drift variables, and 4) provided data source metadata including DOIs for the ERA-5, IMERGE, and GlobCurrent data sources. The primary purpose of this Version 1.1 release is for science evaluation by the NASA International Ocean Vector Winds Science Team (IOVWST).

Product Summary

Platforms
MODELS ,
METOP-A
Instruments
Computer ,
ASCAT
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
12.5 Kilometers x 12.5 Kilometers
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2007-01-01 to 2014-04-01
Vertical Extent
Maximum Altitude: 10 meters
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2705728324-POCLOUD
Data State
COMPLETE
Number of Files/Granules
35303
Processing Level
2
Published
Updated
Science Keywords
Ocean Currents ,
Planetary Boundary Layer Height ,
Surface Winds ,
Sea Surface Temperature ,
Wind Stress ,
Surface Temperature ,
Surface Winds ,
Air Temperature ,
Precipitation Rate ,
Wind Direction ,
Relative Humidity

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

NASA/JPL. (2023). MetOp-A ASCAT ESDR Level 2 Ancillary Ocean Surface Fields Version 1.1 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/ESDAA-L2C11 Date Accessed: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
era_air_temp_2m ERA5 reanalysis 2-meter air temperature Degrees Celsius float -9999 -40 to 40 1
era_boundary_layer_height ERA5 reanalysis atmospheric boundary layer height m float -9999 0 to 10000 1
era_en_wind_direction_10m ERA5 forecast equivalent neutral wind direction degrees float -9999 0 to 360 1
era_en_wind_speed_10m ERA5 forecast equivalent neutral wind speed m s-1 float -9999 0 to 100 1
era_en_wind_u_10m ERA5 forecast equivalent neutral wind speed in the East-West direction m s-1 float -9999 -100 to 100 1
era_en_wind_v_10m ERA5 forecast equivalent neutral wind speed in the North-South direction m s-1 float -9999 -100 to 100 1
era_rel_humidity_2m Relative humidity calculated based on ERA5 reanalysis inputs 1 float -9999 0 to 1 1
era_sst ERA5 reanalysis sea surface temperature Degrees Celsius float -9999 -4 to 40 1
era_wind_direction_10m ERA5 forecast wind direction degrees float -9999 0 to 360 1
era_wind_speed_10m ERA5 forecast 10 meter wind speed m s-1 float -9999 0 to 100 1
era_wind_stress_direction ERA5 forecast surface wind stress direction degrees float -9999 0 to 360 1
era_wind_stress_magnitude ERA5 forecast ocean surface wind stress magnitude N m-2 float -9999 0 to 10 1
era_wind_stress_u ERA5 forecast instantaneous turbulent surface stress in the East-West direction N m-2 float -9999 -10 to 10 1
era_wind_stress_v ERA5 forecast instantaneous turbulent surface stress in the North-South direction N m-2 float -9999 -10 to 10 1
era_wind_u_10m ERA5 forecast 10-meter wind component in the East-West direction m s-1 float -9999 -100 to 100 1
era_wind_v_10m ERA5 forecast 10 meter wind component in the North-South direction m s-1 float -9999 -100 to 100 1
flags quality flags bit int -1 0 to 526352355 1
globcurrent_u Globcurrent total surface current in East-West direction m s-1 float -9999 -100 to 100 1
globcurrent_v Globcurrent total surface current in North-South direction m s-1 float -9999 -100 to 100 1
imerg_precip_cal Calibrated IMERG precipitation rate mm hr-1 float -9999 -1 to 100 1
lat latitude degrees_north float N/A -90 to 90 1
lon longitude degrees_east float N/A 0 to 360 1
quality_indicator quality indicator for wind retrieval -1 short -1 0 to 5 1
time date and time seconds since 1999-01-01 00:00:00 float N/A N/A 1
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