Lake Change in Alaska
Recent studies have reported that lakes in Alaska are drying up; however, these studies have occurred over small sample areas within Alaska and it is not known how widespread the problem is, if it is not related to any specific region, nor is it known about the rate of drying or the type of lakes that are involved. The objectives of this study, therefore, are to try and assess the extent of lake drying across the entire state of Alaska.
This study would use a number of different methods to understand the what, where, when, why, and how of lake change on the Alaskan landscape. To begin, Landsat TM and ETM data will be analyzed from 1985 to present to identify changes in lake surface area using moderate resolution imagery. This analysis will identify hotspots of change and allow for more detailed investigations in the field and with higher spatial and temporal imagery. Synthetic aperture radar (SAR) imagery will also be used to potentially analyze changes in water storage over time. A pilot area located on the North Slope of Alaska is currently being assessed. SAR imagery provides information on the timing of bottom fast ice formation in the winter and thus a rough idea of lake bathymetry. Analysis of historic and current SAR imagery will allow us to identify the dates at which certain lakes become grounded and provide a dataset to analyze trends over time (i.e. freezing earlier or later than normal). This analysis will be supplemented with climate data to more accurately pinpoint lake specific changes. It will also be coupled with the lake surface area change using Landsat to gain a much better understanding of changing lakes in Alaska. Other types of high resolution satellite imagery would also be used for assessment of using Landsat data for assessing lakes smaller than the nominal Landsat pixel size.
Current Findings: Too numerous to include yet
Principal Investigator: Benjamin Jones (bjones@usgs.gov, 907 786 7033)
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