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| Going to the Source
NOAA Aircraft First Link in Data Gathering
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In order to make accurate predictions of a hurricane’s path
and intensity up-to-the-second information must be obtained directly
from the storm itself. The job of gathering this data falls on pilots
flying National Oceanic and Atmospheric Administration (NOAA) reconnaissance
aircraft loaded with sophisticated equipment—sometimes, into
the very eye of the storm.
These specially equipped NOAA aircraft play an integral role in hurricane
forecasting. Data collected during hurricanes by these high-flying
meteorological stations and from a variety of other sources are fed
into numerical computer models to help forecasters predict how intense
a hurricane will be, and when and where it will make landfall. These
computer models fulfill two important purposes: to help forecasters
make accurate predictions during a hurricane; and to help hurricane
researchers achieve a better understanding of storm processes, thereby
improving their forecast models.
NOAA’s Gulfstream IV SP (Special Performance) jet began hurricane
surveillance missions in 1997 in support of forecasters at its National
Hurricane Center (NHC). The jet, which can fly high, fast and far
with a range of 4,000 nautical miles and a cruising altitude of 45,000
feet, paints a detailed picture of weather systems in the upper atmosphere
surrounding developing hurricanes. This operational data is used in
computer models that help forecasters make current predictions.
The G-IV’s data also supplements the critical low-altitude research
data that is collected by NOAA’s two WP-3D Orion turboprop aircraft.
The P-3’s mission is to provide data for NOAA's Hurricane Research
Division as it continues to improve its hurricane prediction computer
models.
Into The Storm
Slicing through the eyewall of a hurricane, buffeted by howling winds,
blinding rain, hail and violent updrafts and downdrafts before entering
the relative calm of the storm’s eye, the two P-3 turboprop
aircraft probe every wind and pressure change of a storm, repeating
the grueling experience again and again during the course of a 10-hour
mission.
Scientists aboard the aircraft deploy instruments called GPS (global
positioning system) dropwindsondes as the P-3 flies through the hurricane.
These devices continuously radio back measurements of pressure, humidity,
temperature and wind direction and speed as they fall toward the sea,
providing a detailed look at the structure of the storm and its intensity.
For years NOAA pilots have flown P-3s into hurricanes at low altitudes
(1,500 to 10,000 feet) to collect research-mission data critical for
computer models that predict hurricane intensity and landfall. This
information is used differently than the hurricane reconnaissance
information provided to the NHC by U.S. Air Force Reserves WC-130s.
Information from both types of flights, however, directly contributes
to the safety of Americans living along the vulnerable Atlantic and
Gulf coasts.
In addition to flying hurricane research and reconnaissance missions,
the P-3s participate in a wide variety of national and international
meteorological and oceanographic research programs each year. Recently,
these aircraft have been used in major studies on storms approaching
the continents of Europe and North America to improve forecasts and
study the effects of El Niño; atmospheric gases and aerosols
over the North Atlantic; large-scale convective storm complexes in
the Midwest and winter storms battering U.S. Pacific coastal states.
Seeking The Storm’s Path
Since the beginning of the 1997 hurricane season, the G-IV has flown
missions around every Atlantic-based hurricane that has posed a potential
threat to the United States. The jet’s mission covers thousands
of square miles surrounding the hurricane, gathering, with newly developed
GPS dropwindsondes, vital high-altitude data needed for improved numerical
forecast models. The G-IV has added a vital new dimension as it maps
the steering currents that influence the movement of hurricanes.
Data from GPS dropwindsondes that measure pressure, temperature, humidity
and wind information are relayed to the aircraft for transmission
by satellite to NHC headquarters in Miami and the National Centers
for Environmental Prediction in Camp Springs, MD. There the data are
available for many numerical forecast models, providing important
information about regions—mostly over oceans—in which
there are no other sources of weather data.
G-IV flight data are expected to help numerical guidance computer
models improve hurricane landfall and track forecasts by up to 20
percent and to further refine storm intensity forecasts.
After hurricane season, NOAA’s interest in severe weather becomes
focused on the winter storms affecting the western, central and northeastern
United States. NOAA has used the G-IV to help monitor and study these
storms to advance our understanding of them and improve winter storm
forecasts. The G-IV has also been used to study clear air turbulence—a
condition that threatens the safety of air traffic—over the
Pacific Ocean, helping scientists increase their ability to understand
and predict this potentially deadly phenomenon.
Working Together
On several missions during recent hurricane seasons, the high-altitude
G-IV was joined by the P-3s, which fly at much lower altitudes and
collect data that complement the G-IV data. Together, these aircraft
provided the most comprehensive data coverage ever collected in the
environment of hurricanes.
These missions not only provided hurricane forecasters with critical
data via the numerical model forecasts, but also gave real-time indicators
of the overall weather conditions working together that were thought
to be influencing the tracks of the hurricanes. These data will also
enable researchers to investigate the factors related to hurricane
track forecasts and gain further knowledge in this scientific field
of study.
Aircraft Operations Center
The P-3s and G-IV are based at NOAA’s Aircraft Operations Center
(AOC) at MacDill Air Force Base in Tampa, FL. AOC is part of the Office
of Marine and Aviation Operations, which includes civilians as well
as officers of the NOAA Corps, the nation’s smallest uniformed
service. NOAA Corps pilots and civilian flight engineers, meteorologists
and electronic engineers are highly trained to operate in the kind
of adverse weather conditions that keep other aircraft on the ground.
Much of the scientific instrumentation flown aboard NOAA aircraft
is designed, built, assembled and calibrated by AOC’s Science
and Engineering Division. During non-hurricane season months, the
P-3s and G-IV are tailored by AOC engineers for use in other severe
weather and atmospheric research programs and flown by NOAA Corps
pilots worldwide in a variety of weather conditions. |
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