CoastWatch WCRN Dataset Summary

		Dataset Summary
West Coast Regional Node

All Surface Temperature Night-time from the Advanced Very-High Resolution Radiometer

Program: NOAA Polar-orbiting Operational Environmental Spacecraft
Spacecraft: NOAA-17 and NOAA-18
Sensor: Advanced Very High Resolution Radiometer (AVHRR)
Data Stream: High Resolution Picture Transmission (HRPT)
Primary Geophysical Parameter: Surface temperature
Nominal Accuracy: 0.7 degrees Celsius (C) for sea surface, unknown for clouds or land surface temperature
Spatial grid: 0.0125 degrees longitude by 0.0125 degrees latitude, geographic
Spatial coverage: West Coast of North America
Temporal Coverage: Last 60 days + (depending on storage space)
FGDC Metadata Data Quality Act Documentation

Short Description:
High-resolution sea surface temperature derived from the AVHRR sensors carried aboard the NOAA Polar-orbiting Operational Environmental Spacecraft (POES) is one of the flagship products of the NOAA CoastWatch program. This dataset provides AVHRR data in the unmasked state, and will contain temperature measurements of sea surface, land surface, and clouds.

Technical Summary:
CoastWatch offers all surface temperature data from the Advanced Very High Resolution Radiometer (AVHRR) instrument aboard NOAA's Polar Operational Environmental Satellites (POES). Two satellites are currently in use, NOAA-17 and NOAA-18, providing surface temperature images four to eight times daily. The AVHRR sensor is a five channel sensor comprised of two visible radiance channels and three infrared radiance channels. During daytime satellite passes, all five radiance channels are used. During nighttime passes, only the infrared radiance channels are used.

The satellites download data to a NOAA National Weather Service ground receiving station in Monterey, CA, via High Resolution Picture Transmission (HRPT) for the West Coast of North America at approximately 1.47 km resolution. The processing of surface temperature by NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) from these radiance measurements uses the non-linear sea surface temperature (NLSST) algorithm detailed in Walton et al., 1998. This product is the unmasked surface temperature, and will contain data from sea surface, land surface, and clouds. The CLAVR-1 cloudmask (Stowe, 1999) is available seperately. The masked AVHRR sea surface temperature product is also available. The masked product eliminates all surfaces expect for sea surface temperature by applying the cloud and land mask.

Temperature measurements are generally accurate to within 0.7 degrees Celsius for sea surface. The accuracy for land or cloud temperature measurements is unknown. The data are mapped to an equal angle grid (0.0125 degrees latitude by 0.0125 degrees longitude) using a simple arithmetic mean to produce individual and composite images of various durations (e.g., 1, 3, 8, 14-day, and monthly).

Disclaimer:
Users are cautioned that this data is unmasked. All the temperature data should not be considered sea surface temperature. Temperature from land and cloud surfaces will be present. Despite our best efforts, incorrect data may often appear within near real time data sets. NOAA CoastWatch accepts no liability for use of these data products. It is recommended that these products NOT be used for navigation.

Acknowledgement:
If this data is used for presentation or publication, please acknowledge the NOAA CoastWatch Program and the NOAA NWS Monterey Regional Forecast Office.

References and suggested citations:
Stowe, L. L., P. A. Davis, and E. P. McClain, 1999. Scientific basis and initial evaluation of the CLAVR-1 global clear/cloud classification algorithm for the advanced very high resolution radiometer. J. Atmos. Oceanic Technol., 16, 656-681.

Walton C. C., W. G. Pichel, J. F. Sapper, D. A. May, 1998. The development and operational application of nonlinear algorithms for the measurement of sea surface temperatures with the NOAA polar-orbiting environmental satellites, J.G.R., 103: (C12) 27999-28012.

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