The Orion P3sIn 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.
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.
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.
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.
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.
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
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