Overview

This data set contains Arctic TOVS-derived Level-3 atmospheric parameters obtained using the physical-statistical retrieval method of Chedin et al. (1985, Improved Iteration Inversion Algorithm, 3I). The method has been improved for use in sea ice-covered areas (Francis 1994) and the data set has been designed to address the particular needs of the Polar research community. The data set represents the so called Path-P as designated by the TOVS Science Working Group. This research is part of the EOS Interdisciplinary Science (IDS) effort POLar Exchange at the Sea surface (POLES) Funding for this project has been provided by the NOAA/NASA Pathfinder Program.

Variables

LATITUDE_GRID	Latitude for each gridpoint
LONGITUDE_GRID	Longitude for each gridpoint
ELEVATION	elevation for each gridpoint
TEMP	Temperatures at pressure levels: 50,70, 100, 300, 400, 500, 600, 700, 850, 900 mb [K]
WVAPOR	Preciptable water of layers bounded by pressure levels [mb]: 300-400, 400-500, 500-700, 700-850, 850-surface [mm]
SKTEMP	Surface Skin Temperature [K]
HIRS_CLDY	Percentage of cloudy pixels per III retrieval box. [%]
FCLD	Total effective cloud fraction [%]
CLPRESS	Cloud-top pressure [mb]
CLTEMP	Cloud-top temperature [K]
EMISS	Emissivity (MSU Channel 1 50 GHz)
ISICE	Surface Type Flag	0=open water, 1=sea ice, 3=land, 10= Mixed surface, last orbit open water 11=Mixed surface, last orbit ice, 13=Mixed surface, last orbit land
SOLZEN	Average solar zenith angle arccos(cos) [Deg]
PRESS	NCEP sea level pressure [ mb ]
PBLSTRAT	Boundary layer bulk stratification [K]
C_g	Geostrophic drag coefficient over sea ice
ALPHA	Turning angle between geostrophic wind and the surface wind over sea ice.

Temporal Coverage

Currently July 1979-Dec 1996 are available from NSIDC. Data for 1997-1998 will become available in the near future.

Spatial Coverage

North Polar Region: North of 60 Deg. Areas over 1000 m are currently not included so that the Greenland ice sheet is not included. South Polar Region: We will begin processing TOVS Path-P data for the Southern Ocean south of 50 Deg early next year. We expect to have data for the full period processed by mid 2000.

Data Format

The data are daily grids formatted in the Hierarchical Data Format. Detailed documentation on how to read the data is provided with the data set.

Data Access

Documentation

Data Set Description NSIDC)
News on the Path-P data set
AMS 1999 Polar Meteorology Paper (PDF)
TOVS Path-P sampler paper (PDF)
Follow this link for a list of papers

Validation

The data set has been thoroughly validated using data from the Soviet North Pole (NP) drifting stations and from SHEBA. For specific validation results follow the links below:

Applications

TOVS Path-P data are currently being used by the following sample of research projects. If you are using Path-P data and would like to provide a link for this section send us e-mail

P-E climatology of the North Polar Region. David Groves, Atmospheric Science/Polar Science Center, University of Washington. (Groves, 1999)
Arctic Radiative Fluxes from the ISCCP-D1 data set. Jeff Key, Boston University. TOVS Path-P data are used instead of the NOAA/NESDIS profiles
Comparison of infrared flux computation methods. (Chiacchio et al. 1999)
Surface longwave fluxes. Jennifer Francis, Rutgers University. (Francis, 1997)
Derivation of 10-m winds for driving coupled ice-ocean model. D.Haidvogel, Rutgers University.
Surface drag and turbulent fluxes over sea ice . R. Lindsay, Applied Physics Laboratory/Polar Science Center, (Lindsay et al, 1997)
Investigation of SSM/I derived sea-ice parameter errors caused by atmospheric effects. R. Kwok. JPL

Quick Looks

Release Notes

Information regarding known issues:

Related Projects

The NOAA/NASA Pathfinder Program
P-Cube: A Multisensor Polar Pathfinder Data set for Arctic Climate Research
- AMS, Dallas, 1999 paper (PDF)
- P-Cube@NSIDC
AVHRR polar Pathfinder

SSM/I Polar Pathfinder
Polar Pathfinder Coordination Effort/Links to other Polar Pathfinder Programs
EASE Grid info
Distributed processing of TOVS PathP data

DBC paper (PDF)

3I Algorithm development (LMD)

Contacts

NSIDC supports this data set. For more information contact: NSIDC user services

For comments regarding this WEB site contact: www@psc.apl.washington.edu

The TOVS Path-P Team

Jennifer Francis, Institute of Maine and Coastal Sciences, Rutgers University
Axel Schweiger, Applied Physics Laboratory/Polar Science Center, University of Washington
Mark Ortmeyer, Applied Physics Laboratory/PSC, University of Washington

Acknowledgements

Funding for this project was provided by the NOAA/NASA Pathfinder Program and the NASA EOS-IDS Polar Exchange at the Sea Surface. Thanks are due to the folks at LMD: Noelle Scott, Raymond Armante, Claudia Stubenrauch, Chantal Claud, Alan Chedin. We also thank the NOAA Satellite Active Archive (SAA) for providing data. Special thanks go to Peter Topoly and Alex Kidd and to the people working the tape machines. We also thank Rachel Hauser, Julienne Stroeve, and Mary-Jo Brodzik at NSIDC are thanked for providing tools, documentation, and additional QC.