科研之友
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摘要
Kotzebue Sound comprises a large part of the Northwest Arctic Borough (NAB) shoreline. It has a diverse coastal geomorphology. Natural coastal dynamics and global sea-level rise (SLR) are contributing to changes in the erosion and accretion of beaches. Recently published data from the joint project of the University of Colorado (Institute of Arctic and Alpine Research) and National Park Service (Arctic Network Inventory and Monitoring Program) for the first time makes systematic quantitative analysis of coastal changes along the Northwest Alaskan coast possible.
This study is based on shoreline indicators derived from 112 aerial photographs, spanning more than 50 years, from 1950 to 2003, processed by research staff at the Institute of Arctic and Alpine Research. The images were used in this study to locate and digitize the shoreline indicators for 1950, 1980, and 2003. Integration of Geographic Information Systems (GIS) with National Oceanic and Atmospheric Administration's Digital Ahoreline Analysis System (DSAS) provided quantitative measurements of historical coastal changes. Projections of SLR in the Arctic from climate models and historical erosion data were used to estimate future erosion rates.
The results show mean erosion rates of -0.12 to -0.08 m/yr in the region from 1950 to 2003. The northern and southern shorelines showed erosion between 1950 and 1980, but slight accretion/stabilization between 1980 and 2003. These changes possibly correlate with Aleutian low anomaly variations that affected the climate in the area of study. On the basis of the predictions of SLR in the Arctic for 2000-2049 and 2050-2100, mean erosion rates may increase to 0.6-1.65 m/yr. This would translate into an approximately 70-1000-m retreat of the shore, depending on its slope, composition, and geomorphologic type. These results help to assess coastal vulnerability and can contribute to regional planning efforts.
- 出版日期2012-1
