David Verbyla | University of Alaska Fairbanks (original) (raw)
Address: Fairbanks, United States
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Papers by David Verbyla
Remote Sensing and Digital Image Processing, 2004
1University of Maryland, Department of Geography, 2181 LeFrak Hall, College Park, MD 20742 USA 2U... more 1University of Maryland, Department of Geography, 2181 LeFrak Hall, College Park, MD 20742 USA 2U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, 214 Irving I, Fairbanks, AK 99775 USA 3Center for Global Change ...
Canadian Journal of Remote Sensing, 2001
Vol. 27. N... 5. Oilnlur'iicliibrc 21МИ Table 1. Summary of the satellite scenes for... more Vol. 27. N... 5. Oilnlur'iicliibrc 21МИ Table 1. Summary of the satellite scenes for the Seward Peninsula that were used in this study. Sensor Year Date of Acquisition Path Row Time of Acquisition (GMT) Sun Elevation Sun Azimuth TM 1986 29 June 79 14 21:37.4041 46.22 156.10 TM ...
Canadian Journal of Forest Research-revue Canadienne De Recherche Forestiere, 2005
Landsat imagery was used to study the relationship between a remotely sensed burn severity index ... more Landsat imagery was used to study the relationship between a remotely sensed burn severity index and prefire vegetation and the postfire vegetation response related to burn severity within a 1986 burn in interior Alaska. Vegetation was classified prior to the fire and 16 years after the fire, and a chronosequence of remotely sensed vegeta- tion index values was analyzed as
The project goal is to engage students in scientific research as a way of learning science, math,... more The project goal is to engage students in scientific research as a way of learning science, math, and technology in K-12 classrooms by providing an opportunity for student-scientist collaborations. This NSF-funded GLOBE project is of significance to scientists who track plant phenological changes as an indicator of climate change and study carbon cycling. To students it is a means of
ABSTRACT Numerous recent changes in hydrological and land surface features have been cited as evi... more ABSTRACT Numerous recent changes in hydrological and land surface features have been cited as evidence for affects of climatic warming in the Arctic. The strong interaction between permafrost and surface water makes Sub-Arctic regions particularly sensitive to changes due to their association with warmer, discontinuous permafrost, which is more prone to thawing and degradation. Observed changes in lake size and distributions across the Arctic by multiple investigators has been one of the more prominent hydrological changes attributed to climatic warming and thermal degradation of permafrost. A major limitation to prior studies is the lack of quantification of the natural variability in lake areas both between years and over the course of a single year. To quantify the natural variability of lakes across regions of discontinuous permafrost in interior Alaska, we performed a comprehensive multi-temporal survey of lakes within the Yukon Flats region of the Yukon River watershed. Our study region consisted of low-lying, lake-rich alluvial terrace associated with discontinuous permafrost in the Yukon Flats. Previous studies indentified decreasing trends in lake sizes in this region from 1954-2000. We used Landsat imagery, GENIEPro automated feature extraction software and G.I.S. to perform supervised classifications to identify lake dynamics across a multitude of temporal scales. By training GENIEPro to identify lakes in Bands 1,2,3,4,5 and 7 of 30 m resolution Landsat data, we extracted all lakes > 0.09 hectares (1 pixel) in a 4,200 km2 region. We converted these lakes to polygons and performed GIS analysis to quantify the interannual and inter-seasonal variability in lakes between 1986 and 2009. Our analysis also examined variability associated with disturbance events from floods and fires.
Remote Sensing and Digital Image Processing, 2004
1University of Maryland, Department of Geography, 2181 LeFrak Hall, College Park, MD 20742 USA 2U... more 1University of Maryland, Department of Geography, 2181 LeFrak Hall, College Park, MD 20742 USA 2U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, 214 Irving I, Fairbanks, AK 99775 USA 3Center for Global Change ...
Canadian Journal of Remote Sensing, 2001
Vol. 27. N... 5. Oilnlur'iicliibrc 21МИ Table 1. Summary of the satellite scenes for... more Vol. 27. N... 5. Oilnlur'iicliibrc 21МИ Table 1. Summary of the satellite scenes for the Seward Peninsula that were used in this study. Sensor Year Date of Acquisition Path Row Time of Acquisition (GMT) Sun Elevation Sun Azimuth TM 1986 29 June 79 14 21:37.4041 46.22 156.10 TM ...
Canadian Journal of Forest Research-revue Canadienne De Recherche Forestiere, 2005
Landsat imagery was used to study the relationship between a remotely sensed burn severity index ... more Landsat imagery was used to study the relationship between a remotely sensed burn severity index and prefire vegetation and the postfire vegetation response related to burn severity within a 1986 burn in interior Alaska. Vegetation was classified prior to the fire and 16 years after the fire, and a chronosequence of remotely sensed vegeta- tion index values was analyzed as
The project goal is to engage students in scientific research as a way of learning science, math,... more The project goal is to engage students in scientific research as a way of learning science, math, and technology in K-12 classrooms by providing an opportunity for student-scientist collaborations. This NSF-funded GLOBE project is of significance to scientists who track plant phenological changes as an indicator of climate change and study carbon cycling. To students it is a means of
ABSTRACT Numerous recent changes in hydrological and land surface features have been cited as evi... more ABSTRACT Numerous recent changes in hydrological and land surface features have been cited as evidence for affects of climatic warming in the Arctic. The strong interaction between permafrost and surface water makes Sub-Arctic regions particularly sensitive to changes due to their association with warmer, discontinuous permafrost, which is more prone to thawing and degradation. Observed changes in lake size and distributions across the Arctic by multiple investigators has been one of the more prominent hydrological changes attributed to climatic warming and thermal degradation of permafrost. A major limitation to prior studies is the lack of quantification of the natural variability in lake areas both between years and over the course of a single year. To quantify the natural variability of lakes across regions of discontinuous permafrost in interior Alaska, we performed a comprehensive multi-temporal survey of lakes within the Yukon Flats region of the Yukon River watershed. Our study region consisted of low-lying, lake-rich alluvial terrace associated with discontinuous permafrost in the Yukon Flats. Previous studies indentified decreasing trends in lake sizes in this region from 1954-2000. We used Landsat imagery, GENIEPro automated feature extraction software and G.I.S. to perform supervised classifications to identify lake dynamics across a multitude of temporal scales. By training GENIEPro to identify lakes in Bands 1,2,3,4,5 and 7 of 30 m resolution Landsat data, we extracted all lakes > 0.09 hectares (1 pixel) in a 4,200 km2 region. We converted these lakes to polygons and performed GIS analysis to quantify the interannual and inter-seasonal variability in lakes between 1986 and 2009. Our analysis also examined variability associated with disturbance events from floods and fires.