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History of the
National Oceanic and Atmospheric Administration's
Hurricane Research Division

The Beginning

Dr. Robert Simpson Since 1944 the United States Navy (USN) and the United States Air Force (USAF) had been flying reconnaissance missions into tropical cyclones, to help warn civilians as well as military personnel of approaching typhoons and hurricanes. Dr. Robert H. Simpson, during the late 1940s and early 1950s, had used these operational reconnaissance missions to take scientific measurements of hurricanes. But it wasn't until 1954, when Hurricanes Carol, Edna, and Hazel swept up the eastern coast of the United States (Hazel went directly over Washington, D.C.), that policymakers took the hurricane threat seriously enough to finance such research. Congress in 1955 authorized additional funding for the United States Weather Bureau (USWB) to create the National Hurricane Research Project (NHRP) which was to conduct research into hurricanes in hopes of improving scientific understanding of them, which in turn would improve forecasting.
Simpson 1980 Dr. Simpson was appointed Director of the twenty-two person Project and in one year he had the operational headquarters set up at the West Palm Beach, Florida airport. USAF loaned three aircraft and their crews to the effort, and on August 13, 1956 the first NHRP flight was made into Hurricane Betsy off the Turks and Caicos Islands.
NHRP logo The USAF aircraft used in the first three years of the Project were a B47 jet and two B50 ex-bombers, which were instrumented to take temperature, humidity, and pressure measurements and punch them on computer cards, and an on-board radar scope, which was photographed at regular intervals. On the ground the cards were read into an IBM 403 tabulating machine which plotted out the tracks onto 11" by 14" pin-fed sheets which were then taped together. The data had to be hand analyized and drafted before publication.

Researchers were initially interested in describing the three dimensional structure of hurricanes and in observing the middle and upper level winds which were thought to steer the storm. Over the next several years an experiment was carried out in which a balloon-borne radio beacon was released in a hurricane's eye and the wind center was tracked remotely.
Dr. Cecil Gentry The Project was also involved in setting up upper-air stations around the Caribbean, and in installing WSR-57 radars in American coastal locations. There was a program of photographing hurricanes from low flying rockets that was soon made obsolete by the introduction of weather satellites. 1958 was the most productive year of this era, with twenty-three missions being flown, and important papers being published on mean atmospheric soundings, hurricane rainfall distributions, storm surge surveys, and radar descriptions of hurricane structure. Unfortunately, at the end of that hurricane season the USAF withdrew their aircraft from the Project. Dr. Simpson left the Directorship to become Director of Project STORMFURY, and Dr. Cecil Gentry became the new NHRP Director.
NHC logo A year later the Project was moved south to the Miami Aviation Building, co-locating it with the National Hurricane Center (NHC). At this time NHC shared facilities with both the USN and USAF Hurricane Hunters in a Joint Hurricane Warning Center.

The Project's acquisition of an IBM 650 computer at this time allowed for quicker processing of field data. But the first attempts at numerical modeling of hurricanes had to await the arrival of a General Electric 225, which could compile and run programs written in FORTRAN.

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DC 6 There was a hiatus in field research activity until 1960 when NHRP acquired two DC6 airplanes just for hurricane research. In 1961 NHRP's Flight Operations Group (the DC6 crews and their ground support) were split from NHRP into a separate organization, the Research Flight Facility (RFF). This organization would eventually become NOAA's Aircraft Operations Center (AOC). The Project's researchers were left to focus on collecting and interpreting the data, while RFF's personnel concentrated on aircraft maintenance and operations.

The STORMFURY era

Also in 1961 the USN and USWB flew seeding experiments into Hurricane Esther. This lead to the formal organization of Project STORMFURY in 1962, as a joint venture of the USN, USWB, and the National Science Foundation. This Project would continue for more than twenty years and include NHRP, RFF and the USAF in its operations.
A good deal of NHRP's research during the early years of STORMFURY were in areas critical to weather modification, such as cloud physics and storm structure and dynamics. Ironically, studies into natural hurricane variability would eventually lead to questions of the effectiveness of STORMFURY.
Satellites had a dramatic impact on hurricane reconnaissance and research during the early 1960's. It was no longer necessary to send aircraft on long 'fishing expeditions', just looking for signs of tropical disturbances. Using the satellites forecasters could pinpoint where the Hurricane Hunters needed to fly. And researchers for the first time could watch the formation of a hurricane from the very start. New insights into storm genesis were also gained from this 'top-down' perspective. However, the high cirrus Central Dense Overcast of hurricanes still made it necessary to fly planes into these storms to collect information.
The DC6s and some NHRP scientist reached out to the international meteorological community in 1963 and 1964 by participating in the International Indian Ocean Expedition. This was the first in a long series of multi-national experiments to which the Project in its various forms was to contribute its expertise in tropical weather and in airborne meteorological observation.
In 1964 NHRP was redesignated the National Hurricane Research Laboratory (NHRL) to signify a more permanent status. The Project was initially supposed to run for only a few years; time enough, it was thought, to answer all the basic questions about hurricanes. As the complex nature of tropical storms became apparent it was realized that hurricane research needed to be an on-going concern. It was already paying dividends in the development of statistical track forecast models and a storm surge forecast guide.
Univ. Miami Computer Center This year also saw both NHC and NHRL move to the Computer Center Building on the University of Miami campus in Coral Gables, Florida. This move brought the government researchers into closer contact with the academic community and also brought access to the University's computer systems, including an IBM 7044. The greater computing power lead to the development of a numerical storm surge model and to NHC-67, a statistical hurricane track forecast model that outperformed all rivals in 1966. That year the U.S. Government reorganized its earth science agencies into the Environmental Science Services Administration (ESSA). This included the USWB, NHC, RFF, and NHRL.
Work began on multi-layer primitive equation track forecast models and on SANBAR, a dynamic physics model. Gordon Dunn and the staff of NHC published a paper evaluating the positive impact of the previous eight years of computer forecast models on track prognostications. Hurricane computer models were also used to simulate hurricane modification experiments to try to validate the field work of STORMFURY.
In 1967 Dr. Gentry became Director of STORMFURY in addition to NHRL Director. This brought the Project under the direct management of NHRL and required a greater commitment of the Laboratory's personnel and resources. More restrictions were placed on where and when a hurricane could be a candidate for seeding and far fewer experiments were being flown. To increase the opportunity for candidate storms several attempts were made in the early 1970's to move Project STORMFURY's operations to the Pacific, but these plans were put aside each time.
BOMEX HQ Improvements were made to the cloud physics instrumentation on the DC6 in 1968. And for the next two years a series of experiments were carried out which released tracers into hurricanes in an attempt to study the air flow by airborne radar.
In the summer of 1969 the DC6s and several NHRL scientists participated in the Barbados Oceanographic and Meteorological Experiment (BOMEX), a huge multi-national, multi-agency scientific study set east of Barbados. This was the second in a series of such large scale experiments to which the Lab contributed. BOMEX's purpose was to better define the the atmospheric and air/sea interaction processes in the tropics, and hence a better understanding of the energy source of hurricanes.

The Department of Commerce, in 1970, reorganized ESSA into the National Oceanic and Atmospheric Administration (NOAA). This included renaming the USWB the National Weather Service (NWS), and separating the Environmental Research Laboratories (ERL) from the NWS. The National Hurricane Center was kept under NWS, the operational wing of NOAA, while the research laboratories, including NHRL, were put into ERL.
The Experimental Meteorology Laboratory (EML) in collaboration with NHRL began the Florida Area Cumulus Experiment (FACE) in 1970. FACE, which was done in two segments, attempted to document the benefits of cloud seeding over the Florida peninsula. This, in turn, was supposed to prove the efficacy of seeding in modifying hurricanes. Instead the second segment, ending in 1983, proved inconclusive.
In 1971 STORMFURY experiments were flown into a late season Hurricane Ginger. Because of a dearth of candidate storms over the next few years and another hiatus as NOAA acquired new aircraft, this would be the last hurricane modification experiment flown under Project STORMFURY, although the Project would continue for another dozen years flying weather modification experiments into tropical cumulus as part of FACE.
Dr. Noel LaSeur In 1974 Dr. Gentry retired and Dr. Noel LaSeur took over the Directorship. A year later the Experimental Meteorology Laboratory was joined to NHRL to form the National Hurricane and Experimental Meteorology Laboratory (NHEML). This brought the Lab to the largest staffing in its history, with nearly sixty scientist and support personnel.
Another period of high scientific productivity ensued with the development of a Moving Fine Mesh dynamical track model, fascilitated by an IBM 360 computer, and papers published on tropical wave dynamics, air-sea interactions in hurricanes, studies of the boundary layer in hurricanes, calculations of the rain drop spectra in tropical cyclones, and computer simulations of hurricane modification and of hurricanes at landfall.
GATE logo The first experiment under the Global Atmospheric Research Project (GARP) was the GARP Atlantic Tropical Experiment (GATE) in the summer of 1974. A number of NHEML scientist as well as the RFF's DC6s and several NOAA ships were involved in this massive twenty nation effort to examine in detail the tropical waves that come off the west African coast each year, which spawn the Cape Verde hurricanes. The experiment's datasets are still being researched to this day for information on how the tropical Atlantic interacts with the global climate.

The Orion P3s

NOAA P-3s In 1973 it was decided that the DC6s were reaching the end of their useful life, and that NOAA, NHRL, and RFF needed to make a major financial commitment to an upgrade of the air fleet. A C130 had been obtained, but more airplatforms were needed. NHRL and RFF went through a period of belt tightening, including reductions in staff and cancelling all STORMFURY flights for three years, in order to finance the purchase of two Lockeed P3 Orions. P3s had been used by the USN as sub hunters and proved to be reliable workhorses. The new aircraft were outfitted with the latest in computers and weather instruments, including three different radar antenna on each aircraft. The quality of the field data was boosted considerably when these planes became available in 1975 and 1976.
Navy SuperConnie In 1975 the USN ended thirty years of hurricane reconnaissance duty and deactivated its Hurricane Hunter squadrons, leaving this function to the USAF and the NOAA aircraft.
Dr. Stanley Rosenthal When Dr. LaSeur stepped down in 1977, Dr. Stanley Rosenthal took over as NHEML Director. Next year it was made an independent laboratory under ERL, and the year after that NHEML and NHC were moved across Dixie Highway from the University of Miami campus to the Gables One Tower. Dr. Rosenthal had been head of the Laboratory's Theoretical Studies Branch, and under his directorship the emphasis of research moved away from weather modification studies and toward computer modeling.
Field studies were greatly improving with the new radar systems on the P3s. Insights into the fine structure of hurricane rain bands were gained, while studies of the inner vortex core revealed the process of eyewall replacement.

AOML building In 1980 NHEML was organizationally placed under the Atlantic Oceanographic and Meteorology Laboratories (AOML), a group of Miami-based NOAA laboratories which had been housed on Virginia Key since 1973. Two years later the Experimental Meteorological Laboratory portion of NHEML was separated and moved to Boulder, Colorado and the Lab was again called NHRL. Another year later NHRL was moved physically out to AOML on Virginia Key, ending 25 years of co-location with NHC. NHRL was then renamed the Hurricane Research Division (HRD), its current sobriquet, when AOML was redesignated a single Laboratory.

Doppler radar The NOAA C130 was decommissioned in 1981, leaving only the two P3s to carry on hurricane research. To compensate for this the instrumentation on the P3s was greatly improved, with Knollenberg cloud physics probes installed, and in 1982 Doppler processing added to the tail radars. Doppler allowed scientists to derive the hurricane's wind fields by either using radar data from both planes, from a plane and a land based Doppler radar, or even from the same airplane radar from two perpendicular legs. Instead of just having wind information from along the aircraft's track, the wind field from the entire inner core could be mapped out. This provided researchers with greater insight into hurricane structure and dynamics.

Cloud physics image The Knollenberg probes allowed HRD cloud physicists to image individual cloud particles by using an array of laser diodes. As particles pass through the array a laser shadow is cast upon the receiving diodes and the image of the particle is entered into memory. Scientists can see what sort of particles they are flying through in real time, whether rain, graupel, ice, or needles. Also the FSSP probe allows the instantaneous compilation of particle size statistics.
Project STORMFURY came to a formal end in 1982, as no hurricane modification experiments had been flown in over a decade, and as serious doubts about the assumptions of STORMFURY came to be expressed. In part the new cloud physics data showed that the amount of supercooled liquid water available in a hurricane was far less than had been thought, and studies of the natural cycles of storm strength showed that the effect of seeding might have been nugatory. HRD scientists published a paper in 1985 demonstrating many of the flaws in the original STORMFURY premises.

The Synoptic Flow era

Synoptic flow flight track With Hurricane Debby in 1982 the Lab began a series of experiments using Omega dropwindsondes to fill in the vast oceanic data voids in the forecast models. One or both P3s would fly synoptic scale patterns around the hurricane, and every 20 minutes or so drop a sonde out of the plane. The dropwindsonde would drift down on a parachute and radio back to the plane the temperature, humidity, and pressure, and using the Omega navigational signals, triangulate its position. This information was used by the plane's computer to estimate the winds the sonde was falling through. Put together with other drops a three dimensional profile of the synoptic-scale atmosphere surrounding the storm was synthesized. Including this vital information in the hurricane track forecast models was shown to improve the accuracy by 20-30%.
Storm surge prediction A contingent of HRD scientists and technicians remained stationed at NHC to compile catalogs of output from a new storm surge model, the Sea, Lake Overland Surges from Hurricanes (SLOSH). These catalogs mapped possible hurricane flooding and required that each basin be meticulously, numerically rendered. These catalogs were then given to emergency personnel in the target cities to aid in evacuation planning.
Computer modeling during the early 1980's involved work on a 12 level nested grid model as well as quasi-spectral and non-hydrostatic models. On going studies at this time included hurricane forecast track errors, rainfall estimates from land based radars near land-falling storms, and air-sea interactions under hurricanes.
sea surface HRD and AOC used films taken during hurricane flights to update the long out-of-date sea surface catalog used to estimate surface wind speeds by flight directors. Thousands of frames of 35mm and 16mm film were searched for examples, and then correlated to the aircraft wind speed. Sophisticated planetary boundary layer models were used to estimate the surface wind speed that went with those flight level pictures.
A new remote sensing instrument, the Step Frequency Microwave Radiometer (SFMR), was installed in 1983 on one of the P3s. Using the returned microwaves from a downward pointing antenna, and comparing them with an ideal return, the device could estimate the wind speed on the ocean's surface. HRD scientists have been involved in several modifications to the SFMR in efforts to make it an operational part of the aircraft's instrument suite.

EPAC SSTs The dramatic El Niño of 1982/83 spurred research into the relationship of ENSO and Atlantic hurricane frequency, and also renewed interest in hurricane climatology. The historical record was searched for possible precursor signals that might hint at future tropical activity. AOML researchers began looking at decadal and longer patterns in hurricane occurrence that might be linked to long term oceanic cycles.
The mid-1980's was a period when research concentrated on the new Doppler radar and cloud physics data. Papers were published on heat budgets, storm structure, wind fields, and drop spectra.

HRD's microphysicists and radar specialist participated in the preliminary STORM (pre_STORM) experiment in the spring of 1985. Pre_STORM studied mesoscale convective complexes in the vicinity of Oklahoma to better understand their structure, dynamics, and predictability. Although the STORM experiment itself never achieved funding, the data from pre-STORM were processed by the Division scientists and gave them experience in collaborating in a large, multi-agency operation that would become invaluable over the next few years.

Theoretical studies were undertaken to define how asymmetries in the hurricane wind field would affect the track. Model symmetrical storms had asymmetries introduced into their wind fields and the tracks compared. The evolution of the wind field was also studied.

GALE logo The skills of several Division scientist in dropsonde processing, airborne weather research, and land based radar recording led to them be involved in the Genesis of Atlantic Lows Experiment (GALE) in 1986. The experiment was designed to examine winter storms off the east coast of the United States, with an emphasis on explosively developing storms. Of value in itself, it was also hoped the knowledge gained from GALE would give new insights into rapidly intensifying hurricanes.

EMEX logo The following year, HRD scientists traveled with the NOAA P3s to Darwin, Australia to participate in the Equatorial Mesoscale Experiment (EMEX). EMEX was to profile oceanic cloud clusters in the monsoonal flow near the equator. This data would be important in tropical meteorology, climate studies, and in global climate models.

In 1991 the USAF tried to end its hurricane reconnaissance duties, but under public pressure opted instead to transfer Hurricane Hunter responsibilities to a Reserve squadron. In 1993 they were again designated the 53rd Weather Reconnaissance Squadron (USAFR).

During the Summer of 1991 HRD personnel travelled to Acapulco, Mexico with the NOAA P3s to participate in the Tropical EXperiment in MEXico (TEXMEX). Headed by Dr. Kerry Emmanuel (MIT), the experiment was designed to investigate incipient tropical cyclones as the moved into the Eastern North Pacific, off the Mexican coast, and look at the role of moisture, as measured by equivalent potential temperature, in the formation of hurricanes.

Troubles forecasting the intensity changes of Hurricane Joan in 1988 inspired HRD scientists to try and improve on SHIFOR, the climate and persistence intensity forecast model used as a benchmark. By 1989 work had begun on the Statistical Hurricane Intensity Prediction Scheme (SHIPS). The scheme became operational at NHC in 1995, and by 1997 was showing skill over SHIFOR. The field of intensity forecasting still presents an area where considerable improvment may be made, and HRD continues to collaborate with Co-operative Institute for Research in the Atmosphere (CIRA) scientists on research to improve the SHIPS.

Hurricane Andrew Hurricane Andrew had a major impact on south Florida and on HRD in August of 1992. The AOML facility had only minor damage, as the eyewall struck further south, on the tip of Key Biscayne. But many Division personnel's homes were damaged or destroyed, with the lives of some in jeopardy. Andrew also precipitated a move by AOC to the Tampa area, ending thirty-two years of Miami based operation. It also sparked NHC to move from their Gables One Tower facility to a hurricane-proof center built specifically for them at Florida International University in west Dade county.

Andrew also generated a number of scientific papers by HRD, examining its wind field, damage patterns, and its explosive intensification during landfall. Indeed, rapid intensification (RI) is a problem which HRD continues to explore, with experiments designed to measure the role of warm sea eddies, and parameters added to the SHIPS to attempt to predict RI. By 2000 SHIPS was also forecasting intensity change for storms after landfall. The decay rate of tropical cyclones over land was the basis of several studies by HRD and CIRA scientists.

TOGA COARE Late in 1992 and early in 1993 HRD scientists once again traveled with the NOAA P3s to participate in yet another international weather science project, the Tropical Ocean-Global Atmosphere Coupled Ocean Atmosphere Response Experiment (TOGA COARE). Based at Guadalcanal, the experiment was designed to measure the heat, moisture, and momentum fluxes as well as the rainfall over the warm pool in the western Pacific. This is a critical area in driving the heat engine of the atmosphere.
Dr. Robert Burpee Over the past decade, a series of experiments were conducted on the daily formation and growth of the south Florida sea breeze, that included P3 flights into evolving sea breeze fronts. These studies were supervised by Dr. Robert Burpee, who in 1993 succeeded Dr. Rosenthal as HRD Director. Dr. Rosenthal continued to work for a couple more years as a co-operative researcher. Dr. Burpee had headed the Division's Hurricane Field Program for a number of years, and had spearheaded the Synoptic Flow experiments, which had long needed an aircraft that would fly much higher than the P3s, and sample more of the atmosphere.

The Gulfstream jet era

NOAA G-IV jet NOAA 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 eyewall of Hurricane Guillermo in the East Pacific. Insights were gained about the hurricane boundary-layer wind structure from these and other drops.
Dr. Hugh Willoughby At the start of the 1995 hurricane season Dr. Burpee became Director of NHC, the third NHC Director to come from NHRP/NHRL/NHEML/HRD (after Dr. Simpson and Dr. Robert Sheets). Dr. Hugh Willoughby took over as Director of HRD, and has been in that position since.
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 continues 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 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.
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.

References

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Last modified: 13 August 2001.
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