Mother Nature treated hurricane researchers to a rare light show as they flew the last mission of the most ambitious hurricane study campaign in the Atlantic Ocean. Rarely seen lightning fields and purple sprites were detected in the eye of the hurricane by the ER-2 pilot as he flew more than 19.8 km (65,000 ft) above the Atlantic.
The third Convection and Moisture Experiment (CAMEX-3) officially ends today, although that's not the end of the program. With an extensive collection of data, the scientists and their colleagues will be busy analyzing what they recorded and extracting a better understanding of how hurricanes form and energize as they move across the ocean.
Ironically, the team may have to pack quickly and evacuate, with no time for lengthy farewells (the group photos were already done Saturday) because Georges is threatening Patrick Air Force Base on Florida's east coast, where the CAMEX-3 team is based. The evacuation of the Florida Keys has already been ordered.
The hurricane's farewell gift - the lightning and sprites - are a recently discovered phenomenon that NASA's Global Hydrology and Climate Center, coordinator of CAMEX-3, has been studying. Red sprites and blue jets, as they are known, were seen by high-altitude pilots and Space Shuttle crews in the 1980s, perhaps earlier, but most observers were unsure of what they saw and did not report the events. Sprites and jets are very faint and can be recorded only with cameras using image intensifiers.
Observations from the Shuttle in 1989-91 and aircraft videotapes of sprites in 1993 confirmed their existence. The exact cause remains a mystery, although they appear to be a part of the global electrical circuit.
Tuesday's Georges synoptic/water vapor inflow flight was a success. The hurricane had already made landfall over Hispaniola and was impacting the mountains there. Although Tuesday was the DC-8 Airborne Laboratory's last CAMEX-3 flight - the team sent special thanks to the flight crew for its excellent support.
Monday's Georges eye wall flight was a success. Georges showed many unique characteristics including large cloud turrets, variable eye wall winds, and wind speeds up to 148 km/h (80 knots; 92 mph) at 10 km (33,000 ft) altitude. The eye wall pattern was also significantly displaced from the radar eye wall location unlike those seen with Bonnie, Danielle, or Earl.
Hurricane Georges is smaller than Bonnie, the hurricane that NASA and its partners closely studied earlier this season, but is still quite deadly.
From its first calibration flight on Aug. 8 through today, the CAMEX-3 team - which includes aircraft from the National Oceanic and Atmospheric Administration and coordination with the U.S. Air Force Hurricane Hunters - has studied Hurricanes Bonnie, Danielle, Earl and now, Georges. The project also combined resources and objectives with the Texas and Florida Underflight (TEFLUN-B) campaign in which the same aircraft and instruments measured storms - not necessarily hurricanes - the validate the instruments on the Tropical Rainfall Measuring Mission satellite as it flew overhead.
A complete listing of CAMEX-3 and TEFLUN-B missions is given below.
CAMEX-3 - the third Convection and Moisture Experiment - is an interagency project to measure hurricane dynamics at high altitude, a method never employed before over Atlantic storms. From this, scientists hope to understand better how hurricanes are powered and to improve the tools they use to predict hurricane intensity.