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• 1. [Article] VanoJulieCEOASSeasonalHydrologicResponses.pdf

  Citation × Citation Citation Abstract Copy Title: VanoJulieCEOASSeasonalHydrologicResponses.pdf Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart Title: VanoJulieCEOASSeasonalHydrologicResponses.pdf Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart Close

• 2. [Article] VanoJulieCEOASSeasonalHydrologicResponsesSupportingInfoS1.pdf

  Citation × Citation Citation Abstract Copy Title: VanoJulieCEOASSeasonalHydrologicResponsesSupportingInfoS1.pdf Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart Title: VanoJulieCEOASSeasonalHydrologicResponsesSupportingInfoS1.pdf Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart Close

• 3. [Article] Seasonal hydrologic responses to climate change in the Pacific Northwest

  This is the publisher’s final pdf. The article is copyrighted by American Geophysical Union and published by John Wiley & Sons Ltd. It can be found at: http://sites.agu.org/

  Citation × Citation Citation Abstract Copy Title: Seasonal hydrologic responses to climate change in the Pacific Northwest Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart This is the publisher’s final pdf. The article is copyrighted by American Geophysical Union and published by John Wiley & Sons Ltd. It can be found at: http://sites.agu.org/ Title: Seasonal hydrologic responses to climate change in the Pacific Northwest Author: Vano, Julie A., Lettenmaier, Dennis P., Nijssen, Bart This is the publisher’s final pdf. The article is copyrighted by American Geophysical Union and published by John Wiley & Sons Ltd. It can be found at: http://sites.agu.org/ Close

• 4. [Article] 30-Arcsecond monthly climate surfaces with global land coverage

  This is the publisher’s final pdf. The article is copyrighted by the Royal Meteorological Society and published by John Wiley & Sons Ltd. It can be found at: http://onlinelibrary.wiley.com/journal/10.1...

  Citation × Citation Citation Abstract Copy Title: 30-Arcsecond monthly climate surfaces with global land coverage Author: Sharp, Kendra V., Hill, David F., Mosier, Thomas M. This is the publisher’s final pdf. The article is copyrighted by the Royal Meteorological Society and published by John Wiley & Sons Ltd. It can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291097-0088. Title: 30-Arcsecond monthly climate surfaces with global land coverage Author: Sharp, Kendra V., Hill, David F., Mosier, Thomas M. This is the publisher’s final pdf. The article is copyrighted by the Royal Meteorological Society and published by John Wiley & Sons Ltd. It can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291097-0088. Close

• 5. [Article] Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments

  In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation ...

  Citation × Citation Citation Abstract Copy Title: Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments Author: Mosier, Thomas M. In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation as snowpack and long-term storage as glaciers. Accumulation, persistence, and melt of snow and ice are functions of the climate in which they exist and therefore respond to changes in that climate. One important use of water in many regions is for hydropower energy production. While reservoir-based hydropower infrastructure has some ability to absorb changes in timing of streamflow, run-of-river hydropower infrastructure does not. Thus, in assessing the economic feasibility of new or existing run-of-river infrastructure, it is important to account for potential impacts climate change may have over the lifetime of the project. Projecting impacts of climate change on surface water resources, and in particular on run-of-river hydropower resource potential, requires robustly characterizing the linkages between the climate, cryosphere, and streamflow. Two obstacles to increasing our understanding of mountain systems are the sparsity of observation data and complexity of weather patterns. The first part of my research addresses the issue of climate data availability in mountain regions through development of statistical models to characterize the high-spatial resolution distribution of historic and projected future precipitation and temperature. I demonstrate these climate products through projecting long-term changes in snowfall for the Alaska Range, Alps, Central Andes, and Himalaya-Karakoram-Hindu Kush ranges. I then present a framework for assessing conceptual cryosphere hydrology models and implement the framework for two long-term glacier study sites in Alaska, USA. Using this framework, I identify novel formulations for modeling the heat transfer and energy balance of snowpacks and glaciers that improve model robustness relative to the current generation of cryosphere hydrology models typically used in data-sparse mountain environments. I then demonstrate a method for understanding the impacts of projected future climate change on run-of-river hydropower resource potential, using Falls Creek in Oregon, USA as a test case. A core value of this work is producing models that can be straightforwardly applied to any region, thus decreasing the impacts of data disparities between regions on our ability to characterize climate change impacts on mountain regions. Title: Characterizing Linkages Between the Climate, Cryosphere, and Impacts on Run-of-River Hydropower in Data-Sparse Mountain Environments Author: Mosier, Thomas M. In many regions of the world, a significant portion of the surface water originates in mountain headwaters where the timing and magnitude of streamflow is largely dictated by the seasonal storage of precipitation as snowpack and long-term storage as glaciers. Accumulation, persistence, and melt of snow and ice are functions of the climate in which they exist and therefore respond to changes in that climate. One important use of water in many regions is for hydropower energy production. While reservoir-based hydropower infrastructure has some ability to absorb changes in timing of streamflow, run-of-river hydropower infrastructure does not. Thus, in assessing the economic feasibility of new or existing run-of-river infrastructure, it is important to account for potential impacts climate change may have over the lifetime of the project. Projecting impacts of climate change on surface water resources, and in particular on run-of-river hydropower resource potential, requires robustly characterizing the linkages between the climate, cryosphere, and streamflow. Two obstacles to increasing our understanding of mountain systems are the sparsity of observation data and complexity of weather patterns. The first part of my research addresses the issue of climate data availability in mountain regions through development of statistical models to characterize the high-spatial resolution distribution of historic and projected future precipitation and temperature. I demonstrate these climate products through projecting long-term changes in snowfall for the Alaska Range, Alps, Central Andes, and Himalaya-Karakoram-Hindu Kush ranges. I then present a framework for assessing conceptual cryosphere hydrology models and implement the framework for two long-term glacier study sites in Alaska, USA. Using this framework, I identify novel formulations for modeling the heat transfer and energy balance of snowpacks and glaciers that improve model robustness relative to the current generation of cryosphere hydrology models typically used in data-sparse mountain environments. I then demonstrate a method for understanding the impacts of projected future climate change on run-of-river hydropower resource potential, using Falls Creek in Oregon, USA as a test case. A core value of this work is producing models that can be straightforwardly applied to any region, thus decreasing the impacts of data disparities between regions on our ability to characterize climate change impacts on mountain regions. Close

• 6. [Article] Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments

  The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier ...

  Citation × Citation Citation Abstract Copy Title: Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments Author: Beamer, Jordan P. The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier cover change on regional hydrology. The region is data-sparse and contains a complex assemblage of topography and land cover, including a system of mountain glaciers that are retreating at some of the highest rates on Earth. The high rates of runoff from precipitation and glacial melt delivered by coastal rivers influence ocean circulation patterns, rates of global sea level rise, and provide spawning habitat for the large salmon populations. Physically-based hydrological modeling of the major water budget components of the GOA, driven using historical reanalysis weather data and land cover, reveals that the modeled water budget components, particularly precipitation input, vary widely between commonly-used weather products. The majority of the large freshwater flux into the GOA is derived from distributed coastal streams rather than the large inland rivers. The modeled seasonal aggregated GOA hydrograph is dominated by the spring and early summer snowmelt, and supplemented by late summer glacial ice melt. Model results demonstrate good agreement with NASA Gravity Recovery and Climate Experiment (GRACE) satellite data in terms of annual amplitudes and long term losses (ice loss), and suggest that existing GRACE solutions, previously reported to represent glacier mass balance alone, are actually measuring the full water budget of land and ice surfaces. An ensemble of climate models and future emissions scenarios were paired with systematically altered land cover to test the sensitivity of the hydrologic system to changes in regional climate patterns and glacier coverage representative of late twenty first century conditions. Compared with the hindcast simulations, the model results forced with increased regional air temperatures and precipitation inputs and reduced glacier cover produce an increase in the annual GOA freshwater discharge volume. The seasonal GOA hydrograph is flattened due to increased winter runoff from more winter rainfall and less snow accumulation, and lower levels of snowmelt and glacier ice contribution. Large uncertainties exist in the direction of change in the glacier runoff component, primarily due to uncertainties that exist in predicting glacier response to climate change. Hydrological modeling with high resolution and inclusion of relevant physical processes can produce significantly improved products that are of high value to and in demand by numerous other scientific communities. However, the value and accuracy of the output from the hydrologic model is highly dependent on the weather forcing quality. Given the considerable importance of quality weather forcing for hydrologic modeling, it is imperative to assess the suitability of multiple products by evaluating local and regional performance and accounting for uncertainty. Additional efforts should be made to improve the spatial resolution of the reanalysis through downscaling and to strategically increase the number of weather stations at high elevations and incorporate that data into weather forcing datasets. Title: Regional Scale Modeling of Climate, Cryosphere, and Freshwater Discharge in Changing Coastal Mountain Environments Author: Beamer, Jordan P. The glaciated coastal mountain watersheds that drain into the Gulf of Alaska (GOA) provide a model laboratory to explore the challenges of hydrological modeling and study the impact of climate and glacier cover change on regional hydrology. The region is data-sparse and contains a complex assemblage of topography and land cover, including a system of mountain glaciers that are retreating at some of the highest rates on Earth. The high rates of runoff from precipitation and glacial melt delivered by coastal rivers influence ocean circulation patterns, rates of global sea level rise, and provide spawning habitat for the large salmon populations. Physically-based hydrological modeling of the major water budget components of the GOA, driven using historical reanalysis weather data and land cover, reveals that the modeled water budget components, particularly precipitation input, vary widely between commonly-used weather products. The majority of the large freshwater flux into the GOA is derived from distributed coastal streams rather than the large inland rivers. The modeled seasonal aggregated GOA hydrograph is dominated by the spring and early summer snowmelt, and supplemented by late summer glacial ice melt. Model results demonstrate good agreement with NASA Gravity Recovery and Climate Experiment (GRACE) satellite data in terms of annual amplitudes and long term losses (ice loss), and suggest that existing GRACE solutions, previously reported to represent glacier mass balance alone, are actually measuring the full water budget of land and ice surfaces. An ensemble of climate models and future emissions scenarios were paired with systematically altered land cover to test the sensitivity of the hydrologic system to changes in regional climate patterns and glacier coverage representative of late twenty first century conditions. Compared with the hindcast simulations, the model results forced with increased regional air temperatures and precipitation inputs and reduced glacier cover produce an increase in the annual GOA freshwater discharge volume. The seasonal GOA hydrograph is flattened due to increased winter runoff from more winter rainfall and less snow accumulation, and lower levels of snowmelt and glacier ice contribution. Large uncertainties exist in the direction of change in the glacier runoff component, primarily due to uncertainties that exist in predicting glacier response to climate change. Hydrological modeling with high resolution and inclusion of relevant physical processes can produce significantly improved products that are of high value to and in demand by numerous other scientific communities. However, the value and accuracy of the output from the hydrologic model is highly dependent on the weather forcing quality. Given the considerable importance of quality weather forcing for hydrologic modeling, it is imperative to assess the suitability of multiple products by evaluating local and regional performance and accounting for uncertainty. Additional efforts should be made to improve the spatial resolution of the reanalysis through downscaling and to strategically increase the number of weather stations at high elevations and incorporate that data into weather forcing datasets. Close

• 7. [Article] Precipitation-snowmelt timing and snowmelt augmentation of large peak flow events, western Cascades, Oregon

  Despite advances in the understanding of rain-on-snow storms and their resulting peak flows, little is understood about the response of snowmelt to precipitation and the relative timing of the two at multiple ...

  Citation × Citation Citation Abstract Copy Title: Precipitation-snowmelt timing and snowmelt augmentation of large peak flow events, western Cascades, Oregon Author: Jennings, Keith S. Despite advances in the understanding of rain-on-snow storms and their resulting peak flows, little is understood about the response of snowmelt to precipitation and the relative timing of the two at multiple temporal scales within such events. To address this issue, climate, snowmelt, and streamflow data were analyzed for 26 large storms in the H.J. Andrews Experimental Forest in the western Cascades of Oregon. Cumulative net snowmelt was plotted against precipitation for each storm to identify net snowmelt response categories, which were then used to summarize climatic and streamflow data, while the timing of precipitation and net snowmelt was assessed at multiple temporal scales and time ranges with wavelet coherence. Five precipitation-net snowmelt response categories were identified: flat; persistent melt; persistent accumulation; late melt; and late accumulation. Persistent melt events, which were characterized by concomitantly increasing cumulative net snowmelt and precipitation, had the highest mean peak flow and water available for runoff values of the response categories. Large, contiguous regions of significant wavelet coherence at multiple temporal scales were observed in both the persistent melt and persistent accumulation categories, but the phase difference distributions indicated differing snowpack dynamics with pulses of precipitation leading pulses of snowmelt in the former and precipitation being absorbed by the snowpack in the latter. High water available for runoff totals and peak flows were observed in each of the five response categories, but a dewpoint temperature consistently above 0.5°C, elevated wind speeds, and a high fraction of precipitation falling as rain in the persistent melt category facilitated rapid snowmelt rates which were often synchronized with precipitation. Wavelet coherence showed this synchronization to be significant across all temporal scales and time periods for the two largest peak flows in the study, indicating that tightly coupled rainfall-synchrony is essential in generating an extreme rain-on-snow flood. By quantifying the amount and timing of net snowmelt, the categorization scheme provides a means of distinguishing among rain-on-snow events and predicting peak discharge magnitude. Title: Precipitation-snowmelt timing and snowmelt augmentation of large peak flow events, western Cascades, Oregon Author: Jennings, Keith S. Despite advances in the understanding of rain-on-snow storms and their resulting peak flows, little is understood about the response of snowmelt to precipitation and the relative timing of the two at multiple temporal scales within such events. To address this issue, climate, snowmelt, and streamflow data were analyzed for 26 large storms in the H.J. Andrews Experimental Forest in the western Cascades of Oregon. Cumulative net snowmelt was plotted against precipitation for each storm to identify net snowmelt response categories, which were then used to summarize climatic and streamflow data, while the timing of precipitation and net snowmelt was assessed at multiple temporal scales and time ranges with wavelet coherence. Five precipitation-net snowmelt response categories were identified: flat; persistent melt; persistent accumulation; late melt; and late accumulation. Persistent melt events, which were characterized by concomitantly increasing cumulative net snowmelt and precipitation, had the highest mean peak flow and water available for runoff values of the response categories. Large, contiguous regions of significant wavelet coherence at multiple temporal scales were observed in both the persistent melt and persistent accumulation categories, but the phase difference distributions indicated differing snowpack dynamics with pulses of precipitation leading pulses of snowmelt in the former and precipitation being absorbed by the snowpack in the latter. High water available for runoff totals and peak flows were observed in each of the five response categories, but a dewpoint temperature consistently above 0.5°C, elevated wind speeds, and a high fraction of precipitation falling as rain in the persistent melt category facilitated rapid snowmelt rates which were often synchronized with precipitation. Wavelet coherence showed this synchronization to be significant across all temporal scales and time periods for the two largest peak flows in the study, indicating that tightly coupled rainfall-synchrony is essential in generating an extreme rain-on-snow flood. By quantifying the amount and timing of net snowmelt, the categorization scheme provides a means of distinguishing among rain-on-snow events and predicting peak discharge magnitude. Close