ANALYSIS OF 1O-DAY ISENTROPIC FLOW PATTERNS FOR BARROW, ALASKA - 1985-1992

Atmospheric transport patterns to Barrow, Alaska, during 1985-1992 wer e investigated using a newly developed isentropic air trajectory model . The new model features a layer-averaged mode that is activated whene ver an air parcel traveling isentropically approaches the Earth's surf ace. A dynamic preprocessing program ensures that trajectories always arrive at a constant, predetermined altitude. Ten-day back trajectorie s arriving twice daily at 500, 1500, and 3000 m above sea level reveal ed no long-term trends in flow patterns during the 8-year period. Freq uency of transport type was fairly stable from year to year, except in the anomalously warm year of 1989 when increased numbers of trajector ies from the Aleutian region were observed. During the Arctic haze sea son, trajectories suggest that transport of pollution from north centr al Russia occurs near the surface (about 20% frequency), whereas that from northern Europe occurs at higher elevations (about 10% frequency) .