[image-51][image-67][image-83]During a month-long mission of 11 aircraft flights designed to improve the quality of information gathered by the Suomi National Polar-orbiting Partnership, or Suomi NPP, satellite, a NASA ER-2 research plane happened to fly in the area above the tornado that flattened a large swath of Moore, Okla., on May 20.
Many of the satellite calibration flights conducted throughout May were timed to fly directly under the path of Suomi NPP, a partnership between NASA and the National Oceanic and Atmospheric Administration, or NOAA. Generally, the flights tried to capture measurements where the air was clear of clouds during times the satellite is overhead.
The information from these flights is used to establish the absolute accuracy of Suomi NPP’s measurements and allow comparisons of the information from other satellites to verify the overall accuracy for a multitude of observations ultimately benefiting end-user applications, including weather forecasting. This information also provides a wealth of input for future scientific studies.
“Tying the Suomi NPP instruments to absolute standards provides unprecedented analysis needed to fully assess the data quality of Suomi NPP sensors, in this case the Cross-track Infrared Sounder, the Advanced Technology Microwave Sounder and the Visible Infrared Imager Radiometer Suite, which results in improved climate and weather applications,” said Dr. Mitch Goldberg, NOAA Joint Polar Satellite System chief program scientist.
There were also flights to obtain aircraft measurements coincident with the NASA Aqua satellite, which gathers information about Earth’s water cycle, and MetOp-A and MetOp-B, two polar-orbiting satellites operated by European Organization for the Exploitation of Meteorological Satellites.
On the day of the Moore, Okla., tornado, the researchers wanted to take advantage of forecast conditions to try to observe a severe storm. Based on a five-day forecast issued on May 16 for the Oklahoma City area, afternoon convection was forecast and mission planners saw an opportunity to observe the pre-convective atmosphere from four different satellites: MetOp-A, MetOp-B, Aqua and Suomi NPP, along with data from their aircraft and an instrumented ground site.
In the area of the tornado, the ER-2 aircraft was flying at about 65,000 feet (19.8 kilometers). The pilot estimated that the highest cloud top near the tornado’s convection to be about 62,000 feet (18.9 kilometers). The pilot reported the plane slowly pitched up and then back down as the air temperature changed near the convection. Because the scientists prefer that the aircraft fly as level as possible, the pilot said he switched off the autopilot and flew manually in order to stabilize the aircraft quickly.
“The plan was to get to the site before the convection started and record the conditions,” said Chris Miller, ER-2 mission manager at NASA’s Dryden Flight Research Center in Edwards, Calif. “The pilot watched two large storms form in the target area and move northeast. He had no idea there was a tornado embedded in the clouds below.”
NASA’s high-altitude ER-2 aircraft, based in Palmdale, Calif., is outfitted with several sensors for the mission designed to ensure accurate measurements from the instruments aboard the Suomi NPP satellite, to benefit both climate researchers and weather forecasters.
Atmospheric properties obtained by instruments aboard the satellites are observed and validated by the sensors on the ER-2 and ground-based observations from the Department of Energy’s Atmospheric Radiation Measurement Climate Research Facility in Lamont, Okla., which is part of a network of facilities providing data from strategically located U.S. and remote-sensing observatories around the world.
The Suomi NPP partnership between NASA and NOAA, has five instruments that are providing scientists with data to extend more than 30 key long-term measurement records. These datasets, which include observations of the ozone layer, land cover, atmospheric temperatures and ice cover, provide critical data for global change science.
These data are critical for the understanding of long-term climate change while also increasing the ability to improve weather forecasts in the short term. NOAA meteorologists are incorporating Suomi NPP information into their weather prediction models to produce forecasts and warnings that already are helping emergency responders anticipate, monitor and react to many types of natural events.
One of the important applications of satellite data is to be able to predict when severe storms will start. “This is best performed from a geostationary satellite which provides nearly continuous observations. However, current geostationary satellites do not have the advanced instrumentation flying on polar-orbiting satellites such as Suomi NPP that is needed to observe the atmospheric changes responsible for severe storm development. We need to use polar-orbiting satellites for this purpose,” said William L. Smith, Sr., distinguished professor of Atmospheric and Planetary Sciences at Hampton University, Hampton Va., and professor emeritus of Atmospheric and Oceanic Sciences at University of Wisconsin at Madison.
The month-long May ER-2 mission was designed to obtain measurements under a variety of conditions, especially targeting cloud-free scenes over the ocean or uniform low stratus clouds. In addition, there are night flights to obtain observations not affected by the sun. Solar reflection by clouds impacts radiation measurements at short wavelengths. Some instruments, such as atmospheric sounders, can be affected by what is known as solar contamination. That is why night flights are used to validate infrared radiance measured by some of the sensors, said Dr. Allen Larar, senior research scientist at NASA’s Langley Research Center in Hampton, Va., and lead government investigator for the project.
Some NASA ER-2 flights were joint missions with an aircraft operated out of Tucson, Ariz., by Met Office, the U.K.'s national weather service. Some of the 11 flights included several regions within Mexican airspace, such as the Gulf of California.
The remote sensing instruments flying aboard the ER-2 on the May flights: the National Polar-orbiting Operational Environmental Satellite System, or NPOESS, Airborne Sounding Testbed Interferometer, or NAST-I, operated by NASA’s Langley Research Center in Hampton, Va.; NPOESS Airborne Sounding Testbed Microwave, or NAST-M, operated by Massachusetts Institute of Technology Lincoln Laboratory in Lexington, Mass.; Scanning High Resolution Interferometer Sounder, or S-HIS, operated by the University of Wisconsin, Madison; The MODIS/ASTER Airborne Simulator, or MASTER, which was developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, and Moderate Resolution Imaging Spectroradiometer, or MODIS, projects, operated by NASA Ames Research Center, Moffett Field, Calif.; and Airborne Visible Infrared Imaging Spectrometer, or AVIRIS, operated by NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The Suomi NPP mission is a bridge between NASA's legacy Earth-observing missions and NOAA's next-generation Joint Polar Satellite System missions. Suomi NPP carries groundbreaking new Earth-observing instruments that the system will use operationally. The first satellite in the JPSS series, JPSS-1, is targeted for launch early 2017.
The ER-2 is one of a fleet of modified aircraft that support NASA’s Airborne Science Program under the Science Mission Directorate and is based at NASA’s Dryden Aircraft Operations Facility in Palmdale, Calif.