This thesis investigates the use of satellite altimetry techniques for measuring surface elevation changes of ice caps. Two satellite altimeters, Radar Altimeter 2 (RA-2) and Geoscience Laser Altimeter System (GLAS) are used to assess the surface elevation changes of three Arctic ice caps. This is the first time the RA-2 has been used to assess the elevation changes of ice caps - targets much smaller than the ice sheets which are the instrument’s primary land ice targets. Algorithms for the retrieval of elevation change rates over ice caps using data acquired by RA-2 and GLAS are presented. These algorithms form a part of a European Space Agency (ESA) glacier monitoring system GlobGlacier. A comparison of GLAS elevation data to those acquired by the RA-2 shows agreement between the two instruments. Surface elevation change rate estimates based on RA-2 are given for three ice caps: Devon Ice Cap in Arctic Canada (−0.09 ± 0.29 m/a), Flade Isblink in Greenland (0.03 ± 0.03 m/a) and Austfonna on Svalbard (0.33 ± 0.08 m/a). Based on RA-2 and GLAS measurements it is shown that the areas of Flade Isblink below the late summer snow line have been thinning whereas the areas above the late summer snow line have been thickening. Also GLAS observed dynamic thickening rates of more than 3 m/a are presented. On Flade Isblink and Austfonna RA-2 measurements are compared to surface mass balance (SMB) estimates from a regional atmospheric climate model RACMO2. The comparison shows that SMB is the driver of interannual surface elevation changes at Austfonna. In contrast the comparison reveals areas on Flade Isblink where ice dynamics have an important effect on the surface elevation. Furthermore, RACMO2 estimates of surface mass budget at Austfonna before the satellite altimeter era are presented. This thesis shows that both traditional radar and laser satellite altimetry can be used to quantify the response of ice caps to the changing climate. Direct altimeter measurements of surface elevation and, in consequence volume change of ice caps, can be used to improve their mass budget estimates.

The hydrological model WATFLOOD and a volume-area scaling relationship are applied to estimate glacier wastage and seasonal Melt contribution to the headwaters of the North and South Saskatchewan Rivers on the eastern slopes of the Canadian Rocky Mountains from 1975-1998. Wastage is defined as the annual volume of glacier ice melt that exceeds the annual volume of snow accumulation into the glacier system, causing an annual net loss of glacier volume. Melt is defined as the annual volume of glacier ice melt that is equal to, or less than, the annual volume of snow that does not melt from the glacier and instead accumulates into the glacier system. It is proposed that the distinction between these two components of glacier runoff is important in studies of the impact of glacier variations on flow. A comparison of similar glacierised and non-glacierised basin hydrographs shows that glacierised basins have greater specific streamflow in the late summer months of otherwise low flow, and the presence of glaciers in a basin results in a lower coefficient of variation of the July to September and annual streamflow as a result of the natural regulating impact of glaciers on streamflow. Glacier wastage and Melt are estimated from a hydrological-hypsometric comparison of glacierised and non-glacierised basins, mass balance data from Peyto Glacier and the published work of other researchers. The similarity of these results to those from the volume-area scaling approach indicates that this is a suitable method for estimating glacier wastage on a regional scale. Whilst the WATFLOOD results were similar to those from the hydrological-hypsometric approach regionally, there were considerable differences between the estimates of combined glacier wastage and Melt from different methods in the small, highly glacierised Peyto Glacier basin. The WATFLOOD results, and thus the estimates of Melt, are therefore treated with caution and it is proposed that glacier runoff data is collected with which to improve the model calibration, verify results and make uncertainty estimations, currently prevented by the severe lack of data on glaciers in the North and South Saskatchewan River basins.<p> The results show that glacier wastage was smaller than Melt and varied between glaciers, though contributed over 10% to streamflow in a number of basins in the July to September period 1975-1998. Melt was positively correlated with basin glacier cover and contributed over 25% to streamflow from basins with glacier cover as little as 1% in the July to September period. The significance of Melt is manifest in its timing since it is equal to the annual volume of snow that accumulates into the glacier system, the volume of which melts as ice instead of snow thus entering the stream in the later summer months after snowmelt. Future glacier decline is therefore expected to result in an advancement of peak flow towards a snowmelt regime hydrograph, assuming that post glacial basin conditions do not similarly delay snowmelt runoff. The resulting reduced late summer flow, compounded by decreasing wastage contributions, is a concern for agricultural and industrial streamflow users, such as hydropower plants, and threatens ecological habitats. Downstream at Edmonton and Calgary, glacier wastage contributed approximately 3% of streamflow 1975-1998; however, Melt supplied over double this volume of flow thus the concern here is whether reservoir capacities are large enough to store a sufficient volume of the spring peak flow to meet supply needs in the late summer months of decreasing flows.

The hydrological model WATFLOOD and a volume-area scaling relationship are applied to estimate glacier wastage and seasonal Melt contribution to the headwaters of the North and South Saskatchewan Rivers on the eastern slopes of the Canadian Rocky Mountains from 1975-1998. Wastage is defined as the annual volume of glacier ice melt that exceeds the annual volume of snow accumulation into the glacier system, causing an annual net loss of glacier volume. Melt is defined as the annual volume of glacier ice melt that is equal to, or less than, the annual volume of snow that does not melt from the glacier and instead accumulates into the glacier system. It is proposed that the distinction between these two components of glacier runoff is important in studies of the impact of glacier variations on flow. A comparison of similar glacierised and non-glacierised basin hydrographs shows that glacierised basins have greater specific streamflow in the late summer months of otherwise low flow, and the presence of glaciers in a basin results in a lower coefficient of variation of the July to September and annual streamflow as a result of the natural regulating impact of glaciers on streamflow. Glacier wastage and Melt are estimated from a hydrological-hypsometric comparison of glacierised and non-glacierised basins, mass balance data from Peyto Glacier and the published work of other researchers. The similarity of these results to those from the volume-area scaling approach indicates that this is a suitable method for estimating glacier wastage on a regional scale. Whilst the WATFLOOD results were similar to those from the hydrological-hypsometric approach regionally, there were considerable differences between the estimates of combined glacier wastage and Melt from different methods in the small, highly glacierised Peyto Glacier basin. The WATFLOOD results, and thus the estimates of Melt, are therefore treated with caution and it is proposed that glacier runoff data is collected with which to improve the model calibration, verify results and make uncertainty estimations, currently prevented by the severe lack of data on glaciers in the North and South Saskatchewan River basins.<p> The results show that glacier wastage was smaller than Melt and varied between glaciers, though contributed over 10% to streamflow in a number of basins in the July to September period 1975-1998. Melt was positively correlated with basin glacier cover and contributed over 25% to streamflow from basins with glacier cover as little as 1% in the July to September period. The significance of Melt is manifest in its timing since it is equal to the annual volume of snow that accumulates into the glacier system, the volume of which melts as ice instead of snow thus entering the stream in the later summer months after snowmelt. Future glacier decline is therefore expected to result in an advancement of peak flow towards a snowmelt regime hydrograph, assuming that post glacial basin conditions do not similarly delay snowmelt runoff. The resulting reduced late summer flow, compounded by decreasing wastage contributions, is a concern for agricultural and industrial streamflow users, such as hydropower plants, and threatens ecological habitats. Downstream at Edmonton and Calgary, glacier wastage contributed approximately 3% of streamflow 1975-1998; however, Melt supplied over double this volume of flow thus the concern here is whether reservoir capacities are large enough to store a sufficient volume of the spring peak flow to meet supply needs in the late summer months of decreasing flows.

Rock glaciers are dynamic landforms and, as such, exhibit interesting and welldeveloped structural features, which translate to surface morphology in the form of ridges and furrows. These distinguishing features have led researchers to study the physics behind the movement and internal deformation of rock glaciers. For years researchers had no access to the internal makeup of rock glaciers. Thus, proposed models and discussion have been based on theoretical concepts of electromagnetic (EM) wave propogation. With the application of ground penetrating radar (GPR) to provide a view of the interior structure of a rock glacier, researchers had “real” data to verify their models. However, no comparison has been made between a GPR profile and an actual cross-section of a rock glacier. The purpose of this thesis is to validate the fidelity of GPR in showing the actual structure of a rock glacier. A trench that was excavated through the toe of a rock glacier on Mount Mestas in south central Colorado provided a view of the actual structure of the landform. The structure in the trench was compared with GPR and EM data. The GPR study was conducted using a PulsEKKOTM 100A subsurface imaging radar with 25, 50, and 100 MHz antennas, to detect dielectric contrasts within the rock glacier. A frequency domain EM34 by Geonics LtdTM was also used to supplement the GPR data by measuring the rock glacier’s conductivity at various depths. This thesis proved, by utilizing statistics, that GPR is a useful tool in visualizing the interior structure of rock glaciers. The 100 MHz antennas clearly show small scale reflection horizons caused by changes in clast orientation and subsurface material composition. These events coincide with structures seen in the trench. Individual clasts greater than 0.375 m were also recognized as point sources in the GPR profiles. Large continuous bedding layers were observed with the 25 and 50 MHz antennas, which reflect the structure seen in the trench. A large scale thrust fault was also located with the GPR. However, this was not visible in the panoramic photograph because the fault occurs below the base of the trench.

No description available.

No description available.

In the summer of 2008 (June 2nd September 19th) detailed measurements of meteorological conditions and glacier surface properties were conducted in the Belcher Glacier catchment (718 km2), Devon Island Ice Cap, Nunavut, Canada. These measurements were used to force and validate a distributed surface energy balance and sub-surface snow model capable of calculating surface ablation rates and meltwater runoff. This study represents a contribution to the International Polar Year (IPY) Glaciodyn project, whose overall aim is to examine the role of hydrology and ice dynamics in the response of marine-terminating glaciers in the Arctic to climate change. Spatially-averaged total water equivalent (w.e.) ablation was 677 mm w.e., and total predicted runoff during the 2008 summer was 3.9 x 108 m3. Net radiation (87%) was the main source of energy over the study period, followed by the sensible heat flux (13%). Net longwave radiation and the latent heat flux represented an overall energy loss from the surface. Modelled melt season duration lasted from June 17th August 15th, and the majority of ablation occurred in two main periods, from June 26th July 18th, and from July 27th to August 14th. Snowfall and lower air temperatures limited ablation between these dates and after August 15th. Ice exposure at elevations below 1000 m occurred by July 1st. Periods of high ablation rates were associated with positive air temperatures and high net shortwave radiation receipts, and with near surface air temperature gradients that were shallow or inverted (i.e. higher air temperatures at higher elevations). Periods of minimum ablation rates occurred when net shortwave radiation receipts were reduced (e.g. following summer snowfall) and when air temperatures were negative. The largest changes in both the net surface energy balance and ablation rates were linked to changes in surface albedo associated with (i) snowpack removal and ice exposure, and (ii) summer snowfall events. Modelled time series of runoff from individual sub-catchments within the Belcher catchment will be used to force a coupled hydrology and ice flow dynamics model of the Belcher Glacier that will be used to investigate the dynamic response of tidewater-terminating glaciers to surface hydrological forcing.

Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 70-75). Also available via the World Wide Web.

Thesis (M. S.)--Michigan State University. Dept. of Geological Sciences, 2006. / Title from PDF t.p. (viewed on June 19, 2009) Includes bibliographical references (p. 51-54). Also issued in print.

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). "Compiled April 3, 2009." Includes bibliographical references (p. 63-67). Also available via the World Wide Web.