• Energy Research

NeighborCommunities is an ArcMap version 10.4.1 shapefile of line-features (SpatialLinesDataFrame in R) with four attributes giving the “Sub_area” of the study area, the length in km (“length_km”) of the line-feature, the functional class of the new, tall woody vegetation (“NewTWV”), and the bounding vegetation outside the polygon on a given poygon edge (“BoundVeg”). Projection is UTM zone6 with datum of WGS84. Please see NeighborCommunities_README.rtf for further details.

2000 random points across the three study sub-areas were selected for statistical modeling in binomial generalized linear mixed models. These points have digital elevation model (DEM) variables (elevation, slope, aspect, potential insolation in four seasons) and vegetation classifications for 1972 and 2012.

Soil temperatures at 15 cm for up to one year. The samples were blocked by location for up to three vegetation classes (alder, willow, and tundra) but unbalanced.

AbstractWe reanalyzed mass balance records at Taku and Lemon Creek Glaciers to better understand the relative roles of hypsometry, local climate and dynamics as mass balance drivers. Over the 1946–2018 period, the cumulative mass balances diverged. Tidewater Taku Glacier advanced and gained mass at an average rate of +0.25 ± 0.28 m w.e. a–1, contrasting with retreat and mass loss of −0.60 ± 0.15 m w.e. a−1 at land-terminating Lemon Creek Glacier. The uniform influence of regional climate is demonstrated by strong correlations among annual mass balance and climate data. Regional warming trends forced similar statistically significant decreases in surface mass balance after 1989: −0.83 m w.e. a–1 at Taku Glacier and −0.81 m w.e. a–1 at Lemon Creek Glacier. Divergence in cumulative mass balance arises from differences in glacier hypsometry and local climate. Since 2013 negative mass balance and glacier-wide thinning prevailed at Taku Glacier. These changes initiated terminus retreat, which could increase dramatically if calving begins. The future mass balance trajectory of Taku Glacier hinges on dynamics, likely ending the historic dichotomy between these glaciers.

Three sub-areas covering a total projected area of about 14 ha in the western Chugach Mountains of southcentral Alaska were digitized and attributed by vegetation class for 1972 and 2012 from a series of orthophotos. A 1m pixel digital elevation model provided elevation, slope, and aspect (DEM variables). This file contains the DEM attributes and vegetation classification for each 1m pixel.

VegClass is an ArcMap version 10.4.1 shapefile of polygon-features (SpatialPolygonsDataFramein R) with four attributes giving the “Subarea” of the study area, the area in ha (“area_ha”) of the polygon-feature, the functional class of the polygon in 1972 (“Veg1972”), and the functional class of the polygon in 2012 (“Veg2012”). Projection is UTM zone6 with datum of WGS84. Please see VegClass_README.rtf for further details.

Soil pits with location and moisture content. This file has the location data for temperature data loggers listed in the file Soil Temperature data file.

AbstractAlaska's largest city, Anchorage, depends on Eklutna Glacier meltwater for drinking water and hydropower generation; however, the 29 km2 glacier is rapidly retreating. We used a temperature-index model forced with local weather station data to reconstruct the glacier's mass balance for the period 1985–2019 and quantify the impacts of glacier change on discharge. Model calibration involved a novel combination of in situ, geodetic mass-balance measurements and observed snowlines from satellite imagery. A resulting ensemble of 250 best-fitting model parameters was used to model mass balance and discharge. Eklutna Glacier experienced a significant negative trend (−0.31 m w.e. decade−1) in annual mean surface mass balance (mean: −0.62 ± 0.06 m w.e.). The day of the year when 95% of annual melt occurs was five days later in 2011–19 than in 1985–93, demonstrating a prolongation of melt season (May–September). Modeled mean specific discharge increased at 0.14 m decade−1, indicating peak water, the year when annual discharge reaches a maximum due to glacier retreat, has not been reached. Four of the five highest discharge years occurred since 2000. Increases in discharge quantity and melt season length require water resource managers consider future decreased discharge as the glacier continues to shrink.