Data Sets

NSIDC maintains and distributes two TOVS data products as part of the NOAA/NASA Polar Pathfinder Program. The following table lists the TOVS data products available at NSIDC. Click on the data set title to access documentation and order data.

Title Spatial Coverage Temporal Coverage Spatial Resolution Temporal Resolution Parameter(s)

AMSR-E/Aqua Monthly Global Microwave Land Surface Emissivity, Version 1

Dataset Summary

This data set is a global land emissivity product using passive microwave observations from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). The data set complements existing land emissivity products from the Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Sounding Unit (AMSU) by adding land emissivity estimates at two lower frequencies, 6.9 and 10.65 GHz (C- and X-band, respectively). Observations at these low frequencies penetrate deeper into the soil layer. Land surface emissivity estimates for this data set were collected at the following vertically and horizontally polarized (V-pol and H-pol) frequencies: 6.9, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz. Ancillary data used in the analysis, such as surface skin temperature and cloud mask, were obtained from International Satellite Cloud Climatology Project (ISCCP). Atmospheric properties were obtained from TIROS Operational Vertical Sounder (TOVS) observations to determine the small upwelling and downwelling atmospheric emissions as well as the atmospheric transmission. The data set is in monthly format that is extracted from instantaneous emissivity estimates. Data are stored in HDF4 files and are available via FTP.

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

2002/07/01 to 2008/06/30 0.25 deg-0.25 deg 1 month Emissivity

TOVS Pathfinder Path-P Daily and Monthly Polar Gridded Atmospheric Parameters, Version

Dataset Summary

The TIROS-N Operational Vertical Sounder (TOVS) Polar Pathfinder (Path-P) data set consists of gridded daily and monthly Arctic and Antarctic atmospheric data derived from various NOAA satellites. TOVS Path-P daily files are available for the Northern and Southern Hemispheres from 60 degrees poleward at 100 km gridded spatial resolution in an Equal-Area Scalable Earth Grid (EASE-Grid). TOVS Path-P monthly files are available for the Northern Hemisphere only from 60 degrees poleward at 100 km gridded spatial resolution in EASE-Grid. Daily and monthly Northern Hemisphere data are available from January 1979 through current processing, and daily Southern Hemisphere data are available from July 1979 through current processing. Data were created from a modified version of the Improved Initialization Inversion Algorithm (3I) (Chedin et al. 1985), a physical-statistical retrieval method improved for use in identifying geophysical variables in snow- and ice-covered areas (Francis 1994).

Variables retrieved from satellite-observed radiances for this product include atmospheric temperature, water vapor, skin surface temperature, total effective cloud fraction, cloud top pressure and temperature, solar zenith elevation, surface pressure, turning angle between geostrophic wind and surface stress over ice, emissivity, boundary layer stratification, and geostrophic drag coefficient. The algorithm used to generate these grids has been validated through comparisons with surface observations from the North Pole drifting meteorological stations (Schweiger et al. 1999).

The complete TOVS data set is available via FTP in Hierarchical Data Format (HDF). Users may also order subsets of the data for any of the parameters listed above or for specific spatial or temporal coverage.

Data users are encouraged to register before accessing the TOVS data. Registered users automatically receive release notes via e-mail containing notification of data manipulation or formatting modifications.

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N: -60, S: -90, E: 180, W: -180

N: 90, S: 60, E: 180, W: -180

1979/07/12, 1979/01/01 100 km-100 km to Air Temperature, Cloud Top Pressure, Cloud Top Temperature, Cloud Amount/Frequency, Emissivity, Wind Stress, Precipitable Water, Skin Temperature, Surface Air Temperature