Glacier mass and area changes on the Kenai Peninsula, Alaska, 1986–2016

Ruitang Yang,Shichang Kang,Regine Hock,Donghui Shangguan,Wanqin Guo

doi:10.1017/jog.2020.32

Abstract

AbstractGlacier mass loss in Alaska has implications for global sea level rise, fresh water input into the Gulf of Alaska and terrestrial fresh water resources. We map all glaciers (>4000 km2) on the Kenai Peninsula, south central Alaska, for the years 1986, 1995, 2005 and 2016, using satellite images. Changes in surface elevation and volume are determined by differencing a digital elevation model (DEM) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer stereo images in 2005 from the Interferometric Synthetic Aperture Radar DEM of 2014. The glacier area shrunk by 543 ± 123 km2 (12 ± 3%) between 1986 and 2016. The region-wide mass-balance rate between 2005 and 2014 was −0.94 ± 0.12 m w.e. a−1 (−3.84 ± 0.50 Gt a−1), which is almost twice as negative than found for earlier periods in previous studies indicating an acceleration in glacier mass loss in this region. Area-averaged mass changes were most negative for lake-terminating glaciers (−1.37 ± 0.13 m w.e. a−1), followed by land-terminating glaciers (−1.02 ± 0.13 m w.e. a−1) and tidewater glaciers (−0.45 ± 0.14 m w.e. a−1). Unambiguous attribution of the observed acceleration in mass loss over the last decades is hampered by the scarcity of observational data, especially at high elevation, and by large interannual variability.

Highlights

Alaskan glaciers account for ∼12% of the total global glacierized area excluding the Greenland and Antarctica ice sheets (Pfeffer and others, 2014; RGI Consortium, 2017) and are an important contributor to global sea level rise (Dyurgerov and Meier, 1997; Arendt and others, 2002, 2013; Meier and Dyurgerov, 2002; Berthier and others, 2010; Arendt, 2011; Gardner and others, 2013; Larsen and others, 2015; Zemp and others, 2019)
This study aims to quantify recent area and mass changes of all glaciers on the Kenai Peninsula aggregated in four subregions defined by the major icefields of the peninsula
The median elevation of all glaciers fluctuates slightly around ∼1100 m a.s.l., regardless area class which may indicate that the equilibrium line of the Kenai Peninsula glaciers is at a similar elevation

Summary

Introduction

Alaskan glaciers account for ∼12% of the total global glacierized area excluding the Greenland and Antarctica ice sheets (Pfeffer and others, 2014; RGI Consortium, 2017) and are an important contributor to global sea level rise (Dyurgerov and Meier, 1997; Arendt and others, 2002, 2013; Meier and Dyurgerov, 2002; Berthier and others, 2010; Arendt, 2011; Gardner and others, 2013; Larsen and others, 2015; Zemp and others, 2019). Gardner and others (2013) found a mass change of −50 ± 17 Gt a−1 for the period 2003–2009 for all glaciers in Alaska and adjacent Yukon Territory. Johnson and others (2013) found highly variable mass change rates for the glaciers in the Glacier Bay region (∼6400 km2) during the period 1995 and 2011 with no clear trend, while Das and others (2014) found a decrease in mass balance of all glaciers in the Wrangell Mountains (∼5000 km2) from −0.07 ± 0.19 m water equivalent (w.e.) a−1 in 1957–2000 to −0.24 ± 0.16 m w.e. a−1 in 2000–2007 uncertainty ranges overlap. All five benchmark glaciers in Alaska (Gulkana, Wolverine, Lemon Creek, South Cascade and Sperry Glacier) have lost mass with average mass-balance rates ranging from −0.58 to −0.30 m w.e. a−1 since mid-20th century (O’Neel and others, 2014; O’Neel and others, 2019)

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