The composite images in this database are created using data collected by the Advanced Very High Resolution Radiometer(AVHRR). We record approximately 9 of these passes per day that are then averaged into one daily composite image. These images are just a small sample of the area over which we can collect data. The satellite dish on our roof allows us to see as far south as Puerto Rico, as far west as Nevada, and up to 65 degrees N latitude and 40 degrees W longitude. The images on the following pages have been calibrated to show sea surface temperatures. Land temperatures, though slightly inaccurate, show the heat emitted from major cities (such as Philadelphia and NYC). Currently we track the NOAA-15, 17 and 18 satellites.

The AVHRR sensor has a spectral resolution of 5 channels in the visible and infrared spectrum. The spatial resolution of the data is 1km.

The raw satellite data is processed to sea surface temperature using the Multi-channel Sea Surface Temperature (MCSST) algorithm using SeaSpace Terascan software. For detailed information on this algorithm check out the primer written by our colleague Dr. Frank Monaldo at Johns Hopkins University.

Each day at midnight all the avhrr imagery collected for that day are used to create a daily composite image. First, clouds are dialated (expanded outward) by 1 pixel to reduce the influence of extraneous bad temperature values along the edges of clouds on the composite averaging. Then we calculate the mean average of valid data at each pixel location in the scene. The data is then smoothed using a 3x3 mean smoothing operator to improve image quality. These composite data are not currently stored in an HDF file format like our daily data. We plot the data using Matlab and archive the jpeg imagery.

The US coastline (drawn in black) is taken from the NOAA Coastline Extractor database (World Vector Shoreline 1:250,000). Bathymetry (also drawn in black) is obtained from the Smith and Sandwell Bathymetric dataset and units are in feet. Most images have the edge of the continental shelf (600 feet or 100 fathoms or ~200 meters) drawn. Smaller regions have more shallow bathymetric contours.

All time stamps are in Greenwich Mean Time (GMT) which is 4 hours ahead of Eastern Standard Time from March to November and 5 hours a head the rest of the year (daylight savings time is not observed in England).