| 英文摘要: | Nontechnical
This project will explore the characteristics, variability and environmental impacts of a little-studied arctic seasonal atmospheric feature called the Summer Arctic Frontal Zone (AFZ), and how it may change over the next century. Little is known about variability in the AFZ or how it will change in the future. The feature is overlain by a high level jet-like feature, and areas where the AFZ are most pronounced are regions of frequent storm genesis, so understanding it is important to understand and predict weather events. In linking the arctic atmosphere, ocean, land surface and the hydrologic cycle, this study of the AFZ adopts a systems perspective, and steeping the next generation of researchers in systems studies is important for maintaining U.S. preeminence in environmental science, so the project is strongly geared towards support of a graduate student. Results from this study will be integrated into university classes and results will be featured in the National Snow and Ice Data Center?s Monthly Highlights. To communicate climate research to the general public, datasets created for this research will be formatted for Science on a Sphere technology. A research team member and the graduate student will present these data and their significance to the public as a part of science outreach shows at the University of Colorado?s Fiske Planetarium.
Technical
This is an effort to take advantage of data from a suite of advanced atmospheric reanalyses, satellite remote sensing and model experiments to address the characteristics, variability and environmental impacts of the Summer Arctic Frontal Zone (AFZ), and how this seasonal feature may change over the next century. Most prior research concludes that the AFZ develops primarily in response to summer heating contrasts between the Arctic Ocean and snow-free land. The AFZ is best developed along the Eurasian and Alaskan coasts, especially in Eastern Siberia and north of Alaska's Brooks Range, where it appears that temperature gradients are sharpened by topographic trapping of cold Arctic Ocean air. The AFZ at the surface is overlain by a jet-like feature at the tropopause. Areas where the AFZ are best expressed are regions of frequent cyclogenesis, and these cyclones have significant impacts on the summer precipitation regime not only along the Arctic coast, but also over the central Arctic Ocean, which is where many of the lows migrate into and decay. Migration of cyclones into the central Arctic Ocean also likely influences the sea ice state. This study will focus on: how seasonal development of the AFZ relates to variations in the seasonal timing of snow-free conditions over land, the location of the sea ice margin, surface temperatures, and topography; whether there is support for persisting views of ecological controls on the AFZ; how different patterns of atmospheric circulation influence the expression of AFZ; how variability in the AFZ is expressed in terms of patterns of cyclogenesis and summer precipitation; and how the AFZ will change through the 21st century in response to changes in seasonal snow cover, sea ice conditions and potential changes in atmospheric circulation patterns. The study will employ data from three atmospheric reanalyses, sea ice extent from the satellite passive microwave record, Reynolds sea surface temperature, satellite-derived terrestrial snow cover extent, experiments with the Weather Research and Forecasting regional model and output from coupled global models. |