The quantity of seasonal snow stored in the Lake Pukaki catchment, New Zealand has a significant impact on the country's economy through its influence on hydroelectricity generation, tourism, agriculture and conservation. SnowSim is a snow storage model developed for New Zealand conditions that may be used to quantify the catchment's frozen water resource and the melt water derived from that resource. Through implementation on a geographic information system, SnowSim has been applied and optimised to the Lake Pukaki catchment. The optimal parameters found were: temperature-elevation lapse rate of 0.005 ℃ m⁻¹, snow/rain temperature threshold of 2.5 ℃, and a melt to temperature relationship factor ranging from 1 to 6 mm ℃⁻¹ d⁻¹. The melt to temperature relationship factor is significantly reduced from that previously used for a New Zealand wide application of SnowSim. Use of a daily measured lapse rate was found to provide no improvement to the model, considered to be because of the spatial variability of lapse rates. Inclusion of a radiation component also provided no improvement in the model. This is contrary to the experience found in similar model applications in other regions of the world. The lower relative importance of radiation melt (with regard to total melt) in the region compared to continental l℃ations may explain this result. The use of a new precipitation distribution system did improve model results. Daily precipitation measurements were related to a new annual average precipitation surface prior to interpolating them across the region, without any elevation to precipitation relationship. Model free water results required an offset adjustment to bring them into line with measured lake inflows limiting the application of the model to estimation of seasonal variation, relative magnitudes and event frequencies of snow storage. Over four years of data a model output quality criterion of 0.61 (where a value of 1 is a perfect model) was returned. This increased to 0.76 for monthly values indicating a high quality of output at the seasonal scale. Model parameters and output quality are in line with those found using comparable models for various applications around the world. The variety of outputs available from the model provide a valuable resource for applications in the electricity, tourism, conservation and agriculture industries as well as for climate, glacier, snow and mountain research.

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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.

Approved for public release; distribution is unlimited / Presently ice extent forecast models such as the U.S. Navy Polar Ice Prediction System (PIPS) neglect or treat small-scale thermodynamic processes and entrainment unrealistically. Incorporating better algorithms that include more complete physics of the mixed layer dynamics will allow for improved prediction of ice thickness and distribution, open water boundaries, polynyas, and deep-water formation in the polar seas. A one-dimensional mixed layer turbulent kinetic energy (TKE) budget model based on Garwood's NPS mixed layer model for deep convection (Garwood, 1991) was written in MATLAB. The model consisted of a system of ten equations derived by vertically integrating the budgets for heat, momentum, salinity, and turbulent kinetic energy between the sea-ice-air interface and the base of the turbulent mixed layer. The NPS mixed layer model was tested using atmospheric forcing and ocean profiles collected at the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) site. Sensitivity studies using ocean profiles of the Greenland Sea were also conducted to address thermodynamics and ocean profiles that enhance thermohaline circulation. Findings and results as well as recommendations for further study are addressed to extend the relationships determined from small 1-D scales to the larger 3-D scales suitable for improvements to current ice models. / Lieutenant, United States Navy

This study was part of the development of an ice jam flood forecasting system for Hay River, NWT. 2-D numerical models were used to simulate ice processes in an effort to predict ice jam formation. A summer survey was conducted to finalize the bathymetry of the Hay River Delta. Observations were undertaken during freeze-up and the winter to better understand Hay River ice conditions. Ice jam events were surveyed during breakup in 2008 and 2009 for model testing. The data collected was used to develop CRISSP2D and River2D models to simulate observed conditions. Simple tests were conducted with CRISSP2D to better understand the model inputs. CRISSP2D modeling of Hay River was unsuccessful and it limitations were discussed. River2D was able to match observed ice jam profiles. The results were used to create an Ice Jam Profile Generator to assist the Town of Hay River with evacuation planning. / Water Resources Engineering