Faced with the near certainty of a lengthy gap in observations from a key weather satellite, the National Oceanic and Atmospheric Administration (NOAA) is seeking ideas from the public about how to maintain the accuracy of the agency’s weather forecasts despite the loss of satellite-derived data.
Image of Earth taken by the newest polar orbiting satellite, known as the Suomi NPP satellite.
Click to enlarge the image. Credit: NASA
Currently, NOAA uses two polar-orbiting satellites that continuously scan the planet from north to south, and instruments aboard these satellites gather data that is then fed into sophisticated computer models that are used to make weather predictions. In particular, the polar-orbiting satellites gather data on winds and moisture in the upper atmosphere, which compliments information coming from weather balloons that are launched twice daily across the country. The satellites have the advantage of scanning the atmosphere over the oceans, whick lack weather-balloon coverage.
In addition, polar-orbiting satellites, which are different than the satellites that rotate above a fixed point on Earth, also carry instruments used for monitoring volcanic eruptions, gathering sea-surface temperature data, and locating emergency beacons from aviators and mariners in distress.
The next generation of polar-orbiting satellites, known as the Joint Polar Satellite System, or JPSS, has been delayed by mismanagement, billions in cost overruns, and technical development challenges. This has pushed back the launch date of the next polar-orbiting satellite to 2017 at the earliest, which is past the design lifetime of the youngest polar-orbiting satellite currently in orbit.
To figure out how to cope with the loss of satellite-derived data, NOAA is conducting a “Gap Risk Study” that, according to a request for public comment in the Federal Register on Nov. 19, seeks ideas from specialists and the public regarding how NOAA can preserve the quality of its weather model forecasts despite the satellite gap.
“[The study is] intended to provide a comprehensive list of contingency options that could be exercised in the event of a gap in polar satellite observations,” the request states.
Among the ideas under consideration include using alternative sensors aboard other satellites to provide data relevant to weather forecasting, as well as implementing different ways of bringing raw data into computer models, which is known as data assimilation.
The Suomi NPP satellite took this image of Hurricane Sandy as the storm moved northward up the East Coast on Oct. 29.
Click to enlarge the image. Credit: NASA.
“NOAA is taking positive steps to mitigate the negative impacts to NOAA’s numerical weather forecasts that could be introduced by a lack of polar satellite data. To this end, NOAA has commissioned an investigative study to broadly explore all available options, such as substitute observation data, alternative modeling data, and data assimilation improvements. NOAA is convening teams of internal and external experts, industry leaders, foreign partners, and academia to study each of these areas,” the Federal Register listing says.
“As a part of this effort, and to ensure we examine all potential solutions, NOAA is also seeking comments, suggestions, and innovative ideas from the public on how to preserve the quality and timeliness of NOAA’s numerical weather forecasts should we experience a loss of polar satellite environmental data. Through this web portal, the public can submit ideas, review submissions from other parties, and make comments and collaborate on ideas.”
NOAA has warned that starting sometime in 2016, there will be at least a year-long gap between the newest polar-orbiting satellite’s design lifetime and the scheduled launch date of its replacement. The JPSS woes mean that for at least a year, the U.S. will be reliant on just one polar-orbiting satellite, rather than the two that have long been in service.
Since about 80 percent of the data that goes into weather computer models comes from the polar-orbiting satellites, there is the possibility that the accuracy of weather forecasts will be reduced during this time period, particularly medium-range forecasts, which may mean that people will not have as much time to prepare for high impact weather events. For example, NOAA has told Congress that such a data gap could significantly erode the agency’s ability to provide advanced notice of significant weather events, such as the “Snowmageddon” blizzard of 2010.
Data from polar-orbiting satellites also contributes to weather forecasts issued by European agencies, such as the European Center for Medium Range Weather Forecasts, or ECMWF. The ECMWF computer model accurately predicted the path of Hurricane Sandy a week in advance, and is widely regarded as the most accurate medium-range model in the world. But it, too, could become less reliable when some satellite data goes missing.
A slew of reports released during the past year have detailed the JPSS program’s troubles and recommended fixes, including a recent report from the National Academy of Sciences, which warned of a troubling decline in America’s space-based Earth observing systems. The Government Accountability Office and an Independent Review Team convened by NOAA have also raised concerns about the consequences of the data gap. In response to some of these reports, NOAA Administrator Jane Lubchenco instituted a variety of management reforms in September.
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