The NOAA/NASA Pathfinder AVHRR Oceans data sets are global, multichannel, Sea Surface Temperature data derived from the Advanced Very High Resolution Radiometers (AVHRR) on the NOAA/TIROS operational meteorological satellites (NOAA-7, -9, and -11) which provide a continuous daily andcomposite data set from July 1981 through the present. These data, when complete, will enable studies of global Sea Surface Temperature characteristicsover more than a decade. Every effort has been made to provide a consistently processed data record by cross-calibrating instruments and minimizingchanges to the processing algorithm during the processing of the 1981 to present data. These pages only describe data from the AVHRR GAC Oceans Pathfinder. Information about other Pathfinder efforts is described in the PathfinderProgram description. The Pathfinder data are archived and distributed by the EOSDIS Distributed Active Archive Center at JPL PO.DAAC. Data areavailable to all users without restriction. In order to understand the processes involved in global climate change many different scientific measurements are needed A primary function of NASA's Earth Observing System (EOS), the centerpiece of NASA's Mission to Planet Earth, is to distribute such measurements to the scientific community in a form that will optimize their use by the research community. One of the parameters critical to understandinghow the ocean affects climate on a global scale is sea surface temperature (SST). An example of the importance of this measurement are the western boundary currents of the world's oceans which carry tremendous amounts of heat poleward. In an attempt to provide this important measurement to the scientific community, the Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) Pathfinder Project, as a result of a formal agreement between NASA and NOAA, has been charged with reprocessing and thus creating a new high quality SST Data Set suitable for global studies. In 1989 NOAA and NASA initiated their joint Pathfinder Program to generate validated data sets of a quality useful for global change studies. Once the reprocessing is completed an SST data set of greater than 10 years will be available to the scientific community. Because of the tremendous amount of data involved in this project, a major responsibility of the JPL team, in conjunctionwith the Physical Oceanography Distributed Active Archive Center at the Jet Propulsion Laboratory, will be to provide easy access to the data and to ensure the highest possible quality data set. Several scenarios are planned to maximize the utilization of the data. Due to the enormity of the reprocessing task a Benchmark period consisting of years 1987 and 1988 has been established. These will be the first two years processed and quality checked by the JPL team. A significant part of the processing effort deals with regridding the data from an equal-area to equal-angle grid, thus making it more suitable for visualization and image manipulation. The equal-area scheme is not suitable for visualization because the number of SST values in a longitude band varies with latitude. The equal-angle grid has the same number of SST values in both latitude and longitude for the entire globe. The fundamental characteristics of the data will be a 9km spatial resolution set of daily global images wherethe image size is 4096x2048. These data will then be distributed in several formats including the Hierarchical Data Format developed by the National Center for Supercomputing Applications. This format allows data to be shared in a heterogeneous environment with portability across various hardware platforms. In addition, the data will be available in more standard image formats. Incorporating binning procedures implemented by the JPL team these daily images of sea surface temperature will be used to form weekly and monthly composites for distribution. Statistics and quality information dealing with the estimation of thesea surface temperature will also be distributed. Part of the quality control of the data consists of spatial and temporal tests as well as visual inspection of each daily global image by the JPL team. Due to size constraints, initial distribution will be through an FTP site, while the daily images must be sent out via tape. Product Name Band Available Tempo Resolution Format Equal Angle 9km 1. Sea Surface Temperature Daily, 8 Days HDF 2. Pixel Quality Composite Monthly, 3. Number of Observations and Yearly Equal Angle 9km Best 1. Best Sea Surface Temperature Daily, 8 Days HDF SST Composite Monthly, and Yearly Raw Binary Equal Angle 1. Best Sea Surface Temperture Daily, 8 Days Binary Best SST 9km 2. Number of Observations Composite Monthly, and Yearly Equal Angle 18km 1. Sea Surface Temperature Daily, 7 Days HDF 2. Pixel Quality Composite Monthly, 3. Number of Observations and Yearly Equal Angle 18km Best 1. Best Sea Surface Temperature Daily, 7 Days HDF SST Composite Monthly, and Yearly Raw Binary Equal Angle 1. Best Sea Surface Temperture Daily, 7 Days Binary Best SST 18km 2. Number of Observations Composite Monthly, and Yearly HDF Equal Angle Browse 1. Best Sea Surface Temperature Daily, 7 Days HDF (720x360) Composite Monthly, and Yearly HDF Equal Angle Browse 1. All Pixel SST Daily, 7 Days HDF all pixel 2. Number of Observations Composite Monthly, and Yearly