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WinterStorms 2004 Background

Concurrent with NCEP's Winter Storms Reconnaissance Program 2004, the NOAA ESRL CSD (formerly the Aeronomy Lab) will conduct the Pacific Sub-tropical Jet Study 2004. The study will investigate the transport of ozone in the vicinity of the Pacific jetstream, a compact area of high winds that strongly affects the transport of air between the layers of the atmosphere as well as in the east/west and north/south directions.

Ozone is a gas that occurs both in the troposphere (where it affects climate and is a pollutant at the Earth's surface) and the stratosphere (where it is more abundant and where it absorbs much of the sun's biologically harmful ultraviolet radiation). During the mission, CSD scientists will measure ozone from the NOAA GIV-SP research aircraft. Flights will be based out of Honolulu and will occur in late January and again in early March.

Combined with the pressure, temperature, humidity and wind data being gathered during the mission, the ozone data will help researchers to unravel the Pacific sub-tropical jetstream's complex effects on the atmosphere. Flights will slice through the jet in the east-west direction to get a rare look at how ozone varies along the way. In addition, scientists will drop several pressure/temperature probes from the aircraft during the flight. The probes (called dropsondes) will measure pressure and temperature as they descend, providing a "curtain" of meteorological data that will be used to analyze the movements of the air. This data will be particularly valuable in studying "folds" that occur in the atmosphere in the vicinity of that jet. These folds can act as conduits for the exchange of air between the ozone-rich stratosphere and the troposphere, thereby strongly influencing ozone abundances in both regions.

The study area is the mid-Pacific region north of Hawaii. The mission should help scientists learn more about the factors that affect ozone abundances in the air that eventually arrives at the U.S. west coast, which influences air quality in that region. Measurements have indicated that ozone in the air arriving at the west coast has been increasing in recent years, and the 2004 study should provide insights into the natural and anthropogenic factors that underlie those observations.