NOAA G-IV Winter Storms Reconnaissance Update

As of February 9, 2003, the NOAA Gulfstream IV-SP (G-IV) has conducted five missions supporting the National Centers for Environmental Prediction (NCEP) Winter Storms Reconnaissance (WSR-03) operational effort in 2003. Flight tracks have varied from east toward California to straight north approaching the Aleutians to NW over Midway, all in the yearly effort to improve weather forecasts from coastal California to the US east coast. One mission was flown to improve a significant snow event in Alaska, while February 9th flight profiled a cold low pressure region east of Hawaii that will bring heavy rain between San Diego and Sacramento Tuesday, February 11th through Thursday, February 13th.

Picture of David Brogan with DropSonde

A typical NOAA G-IV Winter Storms flight originates and returns to Hawaii after about 8 hours aloft, cruising at altitudes between 41 and 45 thousand feet. During the course of a mission, 16 to 25 dropwindsondes are released to vertically profile the atmosphere below the G-IV, resulting in readings of temperature, relative humidity, pressure, GPS-calculated wind direction, and wind speed. These atmospheric measurements are quality assured by meteorologists from the NOAA Aircraft Operations Center (AOC) and transmitted by satellite communication to NCEP, for inclusion into computer forecast models. The added data from the G-IV has been shown, in most cases, to improve the storm forecasts in terms of location and intensity by up to 20%, resulting in more accurate storm warnings for safety to people and property.

Bill Kuster & Megan Northway, Scientists, Aeronomy Lab Helping improve the forcast for severe weather is not the only activity for the G-IV during its two-month tour in Hawaii between January 15th and mid-March. Several air chemistry instruments installed and sponsored by the NOAA Aeronomy Laboratory are continuously sampling the tropospheric and stratospheric air the aircraft encounters during the WSR-03 missions. These instruments measure ozone, which is known to have high concentrations in the lower stratosphere, and uses a mass spectrometer to measure carbon monoxide and hydrocarbons, compounds strongly related to man-made pollutants. Also, starting on February 20th, the NOAA G-IV will become one of the key measurement platforms for the NASA Thorpex-OST project, which involves coordinated missions with the NASA ER-2 high-altitude research jet, and a drifting balloon that follows air currents in the very high atmosphere and periodically launches dropwindsondes. Most of the Thorpex-OST measurements will take place below polar-orbiting, earth-observing satellites to help NASA calibrate and validate these satellite-generated readings. The NASA project ends on March 12th.