Figure 1 NOAA Profiler Network and the Approximate Flight Path of Columbia

NOAA's Profiler Network (NPN) Program received requests Monday, February 03, 2003, from NASA and the National Transportation Safety Board (NTSB) for NPN upper-air wind data collected during the breakup of the space shuttle Columbia. Nine of the 35 NPN profiling clear-air radars, located in the states of New Mexico, Texas, Oklahoma, Arkansas and Louisiana, were near or directly under the flight path of the shuttle (see Figure 1). Because the unmanned profilers automatically acquire wind data continuously from near the ground up to 53,000 feet, the times, horizontal and vertical positions of the falling fragments of Columbia were captured in the data.

The radar data from the profilers located at Palestine, TX and Winnfield, LA detected falling fragments from Columbia as it disintegrated. At Palestine, some larger fragments falling at speeds of 30 feet per second or more were detected minutes after NASA lost communications with Columbia. At Winnfield, a fall of much smaller but far more numerous particles was detected four to six hours following the breakup. It is likely that some are fine particles of aluminum from the shuttle's skin and frame, for they were highly reflective.

NOAA's Forecast Systems Laboratory (FSL) collected NPN data, reports from dozens of boundary-layer profilers operated by cooperative agencies, and water vapor data acquired using GPS-based technology and wrote them onto CD-ROMs. The CDs were sent by overnight package service to National Weather Service's (NWS) Southern Region Headquarters in Ft. Worth, TX, which is handling all coordination with NASA, NTSB and the Federal Emergency Management Agency (FEMA). Staff experts on the NPN will be available at FSL to provide technical support for the forensic analysis of the shuttle breakup. The NPN is unique in that no other observing system can provide the detail of information so critical for determining the time and space parameters associated with the Columbia breakup.

The Forecast Systems Laboratory in Boulder, Colorado, operates and maintains the NPN for NOAA. The National Weather Service uses data from the 35 network profilers routinely in computer-generated forecasts, and its field forecasters tailor model guidance to local conditions. The NPN data are also available on the Global Telecommunication System for international users, and to everyone via the World Wide Web at http://www.profiler.noaa.gov/. Data are used by many other federal, state and local organizations for support in weather forecasting, aviation, and monitoring climate and air quality. One of NPN's customers is Lawrence Livermore National Laboratory, which uses NPN data as critical input to its dispersion model. The model supports work under contract to the Departments of Defense and Energy for Homeland Security.

Figure 2 shows typical winds measured by a Profiler, plotted once every hour from near the earth's surface to above 50,000 feet. Wind speeds are color coded, and the wind direction is identified by the angle of each of the "flag and barbs" displayed. (More information is available at http://www.profiler.noaa.gov/npn/aboutProfilerData.jsp.) Note the changing wind speed and direction, most apparent at the lower elevations (below about 500 mb, or 18,000 ft). This shows the typical meteorological use, or aspect of the data. In this case, the Palestine, TX profiler wind data were actually measured around the time of the accident (2/1/03 14:00 UTC). Note the missing wind data centered around 45,000 ft at 15:00 UTC. The falling pieces of the shuttle caused this area of missing data in the hourly averaged winds (acquired between 14:00 and 15:00 UTC).

Figure 3 shows a very unique view "looking upward" above the Palestine profiler site. The measured vertical velocities are displayed as color; yellow to red colors for downward motion, and blue to purple as upward motion. Vertical velocity data are measured by the Profiler once every 6 minutes. A rather consistent pattern of downward falling objects are apparent above about 45,000 ft immediately following the time of the shuttle breakup (~14:00 UTC). Many of these objects are falling with a velocity of 25-35 ft/s, but apparently still have much larger horizontal velocities and pass quickly through the four degree wide radar beam. Note that objects appear to continue to fall through the radar beam for about 30 minutes.