Meteorologists and emergency managers warn that it could significantly reduce the accuracy of three- to seven-day weather forecasts, the kind that gave the first hints — five days out — that a major tornado outbreak would take shape in the Southeast this past April, for example.
Bill Hooke, a senior fellow at the American Meteorological Society, compared what forecasters would experience when a polar-orbiting satellite is lost to waking up after having a small stroke. “The world that you’re looking at wouldn’t seem quite right to you, and you wouldn’t be able to function quite as well,” he said.
Unlike geostationary weather satellites that hover over a particular point, polar-orbiting satellites continuously circle the planet in a nearly north-south orbit. While other weather satellites mainly relay images of clouds and have blind spots near the poles, the polar satellites have instruments that gather a wider array of data from a more expansive area.
They beam back more than 16,000 observations each day, which are fed into computer models used for weather and climate prediction. Polar-orbiting satellites also gather information used for monitoring volcanic eruptions, keeping tabs on sea surface temperatures and detecting the signals of emergency beacons for search-and-rescue operations.
NASA has three polar-orbiting satellites that work in conjunction with those operated by the Defense Department and the European Organization for the Exploitation of Meteorological Satellites. To keep coverage continuous, aging satellites need to be replaced. Two of NASA’s current satellites are not fully functional, and the third is nearing the end of its life.
NASA has a polar satellite slated for launch in October that was meant to have been a prototype but is being rushed into service. It is expected to near the end of its design life in 2016, or possibly earlier, before a replacement will be on the launchpad.
That’s when a gap in weather satellite coverage is likely to occur. Ball Aerospace and Technologies Corp., the main contractor building new polar satellites, hopes to launch the first one in 2017, about two years later than planned.
The new satellite program, known as the Joint Polar Satellite System, or JPSS, is estimated to cost $11.9 billion between fiscal 2011 and fiscal 2026. During fiscal 2011, however, Congress provided only $382 million for the satellite program, $679 million less than President Obama’s budget request.