UNIVERSITY OF ALASKA FAIRBANKS
Alaskan and adjoining Canadian glaciers represent the largest area of ice cover outside of the Polar Regions. Since 1993, the
Geophysical Institute at the University of Alaska (UAF) has performed light aircraft laser altimetry surveys of over 200 glaciers across the region. Analysis of these survey data led to the discovery that the glaciers here are losing mass so rapidly that they contribute significantly to global sea level rise, roughly at the same rate as the entire Greenland icesheet then (Arendt et. al, 2002). Following this discovery, multiple investigations utilizing NASA missions have confirmed and provided greater details of the high rates of Alaskan glacier wastage, using data from the SRTM (Larsen et. al 2007), ICESat (Sauber & Molnia, 2004; Sauber et. al, 2005; Muskett et. al,
2008a, 2008b, 2008c) and GRACE (Tamisiea et. al, 2005; Chen et. al, 2006; Arendt et. al, 2008; Luthcke et. al, 2008). Many of the ice masses in this region are experiencing an ongoing acceleration in mass wastage (Arendt et. al, 2002; Luthcke et. al, 2008; Larsen et. al, 2008).
This is a proposal to collect LiDAR measurements of surface elevation over Alaskan glaciers with the UAF program of light aircraft altimetry. This project will build upon Operation Ice Bridge funded missions performed in 2009 by UAF. During 2009 we began an expansion of the existing UAF program. This expansion was particularly needed to provide additional data coverage between ICESat I and ICESat II, and due to dynamic and accelerating changes occurring across many southeast and south-central Gulf of Alaska coastal glaciers. The targeted glaciers and icefields have been identified as exceptionally dynamic areas of rapid wastage using recent altimetry, GRACE and ICESat studies (Larsen et. al 2007, 2008; Muskett et. al, 2008a, 2008b 2008c; Arendt et. al, 2008; Luthcke et. al,
2008). These targeted glaciers are predominately coastal and calving glaciers. The combination of prodigious precipitation, high mass exchange rates, and dynamic effects enables these glaciers to produce a large percentage of Alaska's total contribution to sea level rise. Current support for the UAF laser altimetry program is nearing the end of the last year of a four year grant from the NSF Arctic Natural Sciences. No data acquisition is budgeted by NSF for 2010. The support requested from NASA herein will be used to perform
surveys that otherwise will not occur. Coordination between the NSF project and NASA's augmentation is simple, as both are aligned along the same overarching goals and questions:
1)Is glacier wastage accelerating in northwest North America?
2)What is Alaska¿s contribution to global sea level rise?
3)What areas are experiencing or are about to experience dynamically driven collapse and retreat?
4)Provide critical baseline data to validate and enhance GRACE studies of regional mass loss.
5)Provide valuable and essential laser altimetry data on Alaskan glaciers between ICESat missions I and II.