NOAA's newest tool for weather forecasting,
a new Gulfstream IV-SP high altitude jet (or G-IV), recently demonstrated
its capabilities as it flew in support of the North Pacific Experiment
(NORPEX) out of Honolulu, Hawaii. NORPEX was designed to collect data in
real-time to add to weather models, providing better one- to four-day warnings
of storms, and to analyze the formation of the storms and other El Niño
events.
The G-IV flew targeted missions over the North Pacific Ocean during the last half of January, deploying GPS dropsondes in areas most likely to improve numerical forecast models. During this experiment, the G-IV covered approximately 3400 miles at altitudes up to 45,000 feet for flights of up to eight hours duration. For NORPEX, the G-IV flew eight missions, deploying a total of 262 GPS dropsondes. The data from the dropsones were transmitted to NOAA's National Centers for Environmental Prediction to update the numerical forecast models. Preliminary indications are that the one to four-day forecast models were significantly improved. The exact improvement will be determined after all the data are analyzed at the National Centers for Environmental Prediction in Camp Springs, Maryland, and the Naval Research Laboratory in Monterey, California.
The
GPS dropsonde is a small cylindrical package designed to measure and transmit
back to the aircraft a vertical profile of the pressure, temperature, relative
humidity and information needed to calculate the wind as the sonde falls to
the surface. In data-sparse regions, such as over the oceans, the GPS dropsondes
are the only means available to determine the vertical wind profile. These profiles
are received back at the aircraft, and are analyzed, processed and transmitted
for near real-time inclusion into the numerical weather forecast models. The
models use profiles of environmental conditions at one moment to step ahead
in time to predict conditions at a future moment.
The G-IV is operated and maintained by NOAA's Aircraft Operations Center based at MacDill Air Force Base in Tampa, Florida. The G-IV is also equipped with sophisticated computer systems for synoptic surveillance missions around hurricanes. These missions provide forecasters at the National Hurricane Center valuable information for predicting intensity, track, and landfall of hurricanes. The crew complement of the G-IV is composed of two pilots, a G-IV equipment specialist, one flight director (a meteorologist), a systems engineer and several electronic technicians. Also, a meteorologist is required to operate the system that analyzes and processes the GPS dropsonde information.
Although the G-IV's primary mission is to support hurricane surveillance and research, the jets speed, range, mission and altitude capabilities are of significant importance to other NOAA scientific programs, like NORPEX.
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