The Gulfstream jet eraNOAA began in earnest in 1994 obtaining a high-altitude jet for hurricane and synoptic weather investigations. A Gulfstream IV (G-IV) jet was purchased by NOAA and instrumented. It was ready to fly by late 1996 and first used in a hurricane synoptic flow mission in 1997. New dropwindsondes were developed to replace the obsolete Omega sondes. The new sondes employed the Global Position Satellites (GPS) to obtain more accurate positions, and hence, more accurate winds. These new sondes were also more liquid water tolerant and for the first time soundings were made inside the hurricane eyewall, in Hurricane Guillermo over the East Pacific. Insights were gained about the hurricane boundary-layer wind structure from these and other drops.
At the start of the 1995 hurricane season Dr. Burpee became Director of NHC, the fourth NHC Director to come from NHRP/NHRL/NHEML/HRD (after Drs. Bob Simpson, Neil Frank, and Bob Sheets). Dr. Hugh Willoughby took over as Director of HRD.
The Division has been experimenting with ensemble predictions. Small perturbations are introduced into a computer model's initial conditions and run several times with different perturbations. The resulting suite of forecasts are then synthesized into one forecast, one from which most chaotic noise has been reduced. These ensemble forecasts help point to areas over the open ocean from which data is most critical, and G-IV dropsonde flights can be planned for these sections.
HRD scientist, with their experience with both the G-IV jet and GPS sondes, participated in the NORth Pacific EXperiments (NORPEX) in 1998 and 1999. Run at the same time as the CALJET experiment using the P3 aircraft, these experiments measured Pacific storms that could threaten the western U.S. coast and examined how they might be affected by the 1997-98 El Niño. NORPEX in 1999 has been renamed Winter Storm Reconnaissance '99. And HRD participation continued with Winter Storm Reconnaissance 2000, operating out of Anchorage, studying Gulf of Alaska polar lows, and WSR 2001, operated out of Honolulu, studying Kona lows and jet stream turbulence.
Work continues on the development on the SFMR as well as a new microwave scatterometer which can measure the wind direction of surface winds from the P3 aircraft, even through rain and clouds. This will provide NHC hurricane specialist with a more accurate assessment of the hurricane's surface winds near the time of landfall.HRD also runs the H*Wind project, which brings together wind measurements from aircraft, satellites, ships, and buoys and creates an integrated near surface wind analysis field. These fields are given to NHC's hurricane specialists in real-time, and are later posted on the World Wide Web for researchers around the globe.
In 2003 Dr. Willoughby left HRD to join Florida International University's International Hurricane Research Center (IHRC). Dr. Frank Marks, for many years the leader of the annual Hurricane Field Program, assumed the Directorship.
HRD will continue on into the 21st Century as NOAA's focus for hurricane research, with extensive co-operation with NHC, AOC, USAF, USN, other government agencies, the academic community, and with the private sector. Improvements in computer forecasts are expected to come with further work, as is improved knowledge of hurricane climatology in a changing world.
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