NOAA's National Weather Service Weather Forecast Office

Satellites

Enormous advances have been made in the area of satellite meteorology since the tragic loss of the Edmund Fitzgerald on November 10, 1975. The latest generation of Geostationary Operational Environmental Satellites (GOES) can produce images as quickly as every 7 or 8 minutes (rapid scan) or even every 30 seconds (super rapid scan). More frequent, higher resolution satellite images allow the forecaster to anticipate and update forecasts based on changing weather patterns much more quickly now than ever before. The satellite in use in 1975, the Synchronous Meteorological Satellite (SMS-1), had only two channels to view the earth (visible and infrared). By comparison, the modern-day GOES satellites have five imager channels. These channels can also be combined to help detect features such as fog and low clouds at night, an impossible task in 1975. Current GOES satellites have improved resolution of imagery by up to four times that available from the SMS-1 and early-generation GOES. GOES satellites also carry a sounder that views the atmosphere with 19 channels, while the SMS-1 lacked this capability. The GOES sounder allows the satellite to sense temperature and moisture through the depth of the atmosphere.

Another technological advance involves recent research with satellites to estimate surface winds over the Great Lakes and oceans using the microwave portion of the spectrum. This is especially useful given the sparse data available from buoys and ships. These improved technologies allow satellite derived parameters such as winds and moisture to be calculated and incorporated into the numerical computer models that National Weather Service meteorologists analyze during the forecast process. Meteorologists can now watch storms progress from their infancy to their dying stages in high detail.

Not only have improvements been made in the ability of satellites to view the earth, but methods to deliver these images to forecasters and users have also improved dramatically since 1975. It was only as recently as the 1990s that the ability to view satellite imagery on desktop computers and workstations became widely available. The Advanced Weather Interactive Processing System (AWIPS), which was introduced to modernized National Weather Service forecast offices across the nation from 1997 - 1999, allows forecasters to view multiple screens of satellite imagery along with other weather data. The ability to view such an assortment of satellite imagery and other meteorological data in tandem has never before been available. This system also allows meteorologists to enhance satellite imagery in color to highlight significant patterns and animate the imagery on workstation monitors. This is a vast improvement from 1975 when meteorologists were generally limited to viewing black and white satellite images on paper copies. Some weather offices in 1975 received only a few of these satellite images per day. The end result of these technological advances is improved marine weather forecasts and the ability to give longer lead time for gale and storm warnings on Lake Superior, thereby allowing people to make more educated decisions about traveling during adverse weather.