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博文

目前显示的是标签为“Alaska”的博文

Active-Layer Soil Moisture Content Regional Variations in Alaska and Russia by Ground-Based and Satellite-Based Methods, 2002 through 2014

Read  full  paper  at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=53322#.VL3BWizQrzE Author(s)   Reginald R. Muskett 1 , Vladimir E. Romanovsky 1,2 , William L. Cable 1 , Alexander L. Kholodov 1   Affiliation(s) 1 Geophysical Institute, University of Alaska Fairbanks, Fairbanks, USA . 2 Tyumen State Oil and Gas University, Tyumen, Russia . ABSTRACT Soil moisture is a vital physical parameter of the active-layer in permafrost environments, and associated biological and geophysical processes operative at the microscopic to hemispheric spatial scales and at hourly to multi-decadal time scales. While   in-situ   measurements can give the highest quality of information on a site-specific basis, the vast permafrost terrains of North America and Eurasia require space-based techniques for assessments of cause and effect and long-term changes and impacts from the changes of permafrost and the active-layer. Satellite-...

Regional Analysis of NASA Satellite Greenness Trends for Ecosystems of Arctic Alaska

Read full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=49169#.VJJRIcnQrzE Author(s) Christopher Potter Affiliation(s) Mail Stop 232-21, Moffett Field, USA . ABSTRACT Trends in the growing season MODerate resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were analyzed for the period from 2000 to 2010 to understand landscape-level patterns of vegetation change in ecosystems of arctic Alaska. We compared datasets for vegetation cover types, wetland cover classes, wildfire boundaries since the 1940s, permafrost type, and elevation to identify the most likely combination of factors driving regional changes in habitat quality and ecosystem productivity. ...