|2002-6||FOR IMMEDIATE RELEASE: April 15, 2002|
Note to Editors: Reporters are invited to the IHOP2002 media day on Monday, May 13. A press briefing will take place at Oklahoma Citys Will Rogers World Airport, where the project aircraft are based. For more details, see the media advisory.
BOULDEROne of the largest weather-related studies in U.S. history will track the nearly invisible swaths of moisture that fuel heavy rain across the southern Great Plains from Texas to Kansas. Scientists hope that analyzing water vapor will be the key to better predictions of when and where summertime storms will form and how intense they will be.
Led by scientists from the National Center for Atmospheric Research (NCAR), IHOP2002 (International H20 Project) will be based in central Oklahoma from May 13 to June 25. The National Science Foundation, NCAR's primary sponsor, is providing the bulk of the projects $7 million funding, with additional support from other agencies. Field activities will be coordinated by the University Corporation for Atmospheric Research (UCAR), which operates NCAR.
Six aircraft from the United States and Germany will traverse the core study area, some flying as low as 100 feet above the surface. A futuristic, semi-autonomous research craft, the Proteus (sponsored by NASA, NOAA and DOD), will carry instruments up to 56,000 feet. On the ground, an armada of 30 weather-tech vehicles, including four Doppler radars on flatbed trucks, will comb the rural roadways of Oklahoma, Kansas, and Texas. Over 100 scientists and technicians scattered across the plains will be aiming radars and other sensors at water vapor well ahead of the day's first raindrops.
Unlike many weather studies held in this region, IHOP is homing in on the water vapor that feeds showers and thunderstorms, rather than trying to capture episodic events like tornadoes or other severe weather.
"We're hoping to actually see how the water vapor moves," says NCAR's Tammy Weckwerth, one of IHOP's two lead scientists. "That's never been done before." Cloud cover may impede some of the more sensitive instruments, Weckwerth adds. "The ideal day will start out cloud free, yet humid."
Where, when, and how hard it will rain are the most difficult elements to nail down in weather forecasting, especially in spring and summer. Better precipitation outlooks are a key goal of the U.S. Weather Research Program, which has organized a number of agencies in support of IHOP. The study aims to improve forecasts from 1 to 12 hours ahead of heavy rain, which could help in flash-flood safety and other applications.
"Right now the lead time for flash-flood forecasts is well under an hour," says NCAR's David Parsons, co-lead scientist on the study. "If you can extend forecasts of heavy rainfall out a few hours, youre doing great."
Heavy rain depends on an ample supply of moisture, so the lack of water-vapor data is a major forecast impediment. Currently, no device can track tiny molecules of water vapor minute by minute over large areas. Weather balloons (radiosondes) provide most of the water-vapor data used in forecasting; however, their high cost reduces the frequency and spacing of balloon launches. Lidar (laser-based radar) provides more detail than radiosondes, but it can only sample across a few miles, and clouds reduce that range further. Satellite sensors, which cover much of the globe, haven't yet furnished the high-resolution measurements needed in the lower atmosphere for storm prediction.
By mixing older and newer sensors, IHOP2002 will examine how the latest technology can bridge the gaps in water-vapor sensing. Four of the IHOP aircraft will carry state-of-the-art systems that produce vertical profiles of water vapor. These will be used to help calibrate new, higher-precision instruments aboard satellites. Other sensors on the ground will analyze signals from the Global Positioning System (GPS) and other sources. Special high-end radiosondes will be launched for comparison with other data. UCAR's Joint Office for Science Support will be coordinating the IHOP2002 operations center in Norman, as well as managing and archiving data.
Forecasters from several labs and universities will use a suite of high-performance computer models to predict each days weather. Rather than simply assigning a chance of rain, the meteorologists will specify rainfall amounts across the study area. Such forecasts are now limited in accuracy, but with the IHOP data at hand, scientists are hoping to improve their skills.
Questions and answers about IHOP field activities
Where and when will aircraft be overhead?
How will the weather balloons (radiosondes) be launched
What other IHOP activities will be noticeable?
More on IHOP instruments and participants
Aircraft (all based at Will Rogers World Airport, Oklahoma City)
Participating institutions from the U.S., Canada, France,