24 results on '"Se-Yeun Lee"'
Search Results
2. Projecting the Hydrologic Impacts of Climate Change on Montane Wetlands.
- Author
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Se-Yeun Lee, Maureen E Ryan, Alan F Hamlet, Wendy J Palen, Joshua J Lawler, and Meghan Halabisky
- Subjects
Medicine ,Science - Abstract
Wetlands are globally important ecosystems that provide critical services for natural communities and human society. Montane wetland ecosystems are expected to be among the most sensitive to changing climate, as their persistence depends on factors directly influenced by climate (e.g. precipitation, snowpack, evaporation). Despite their importance and climate sensitivity, wetlands tend to be understudied due to a lack of tools and data relative to what is available for other ecosystem types. Here, we develop and demonstrate a new method for projecting climate-induced hydrologic changes in montane wetlands. Using observed wetland water levels and soil moisture simulated by the physically based Variable Infiltration Capacity (VIC) hydrologic model, we developed site-specific regression models relating soil moisture to observed wetland water levels to simulate the hydrologic behavior of four types of montane wetlands (ephemeral, intermediate, perennial, permanent wetlands) in the U. S. Pacific Northwest. The hybrid models captured observed wetland dynamics in many cases, though were less robust in others. We then used these models to a) hindcast historical wetland behavior in response to observed climate variability (1916-2010 or later) and classify wetland types, and b) project the impacts of climate change on montane wetlands using global climate model scenarios for the 2040s and 2080s (A1B emissions scenario). These future projections show that climate-induced changes to key driving variables (reduced snowpack, higher evapotranspiration, extended summer drought) will result in earlier and faster drawdown in Pacific Northwest montane wetlands, leading to systematic reductions in water levels, shortened wetland hydroperiods, and increased probability of drying. Intermediate hydroperiod wetlands are projected to experience the greatest changes. For the 2080s scenario, widespread conversion of intermediate wetlands to fast-drying ephemeral wetlands will likely reduce wetland habitat availability for many species.
- Published
- 2015
- Full Text
- View/download PDF
3. Development and validation of an open-source four-pole electrical conductivity, temperature, depth sensor for in situ water quality monitoring in an estuary
- Author
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J. Wesley Lauer, Piper Klinger, Scott O’Shea, and Se-Yeun Lee
- Subjects
General Medicine ,Management, Monitoring, Policy and Law ,Pollution ,General Environmental Science - Published
- 2022
4. Thermal landscapes in a changing climate: biological implications of water temperature patterns in an extreme year
- Author
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E. Ashley Steel, Narasimhan K. Larkin, Aimee H. Fullerton, Akida J. Ferguson, Se-Yeun Lee, Amy Marsha, and Julian D. Olden
- Subjects
010504 meteorology & atmospheric sciences ,Water temperature ,Climatology ,0208 environmental biotechnology ,Thermal ,Environmental science ,02 engineering and technology ,Aquatic Science ,01 natural sciences ,Ecology, Evolution, Behavior and Systematics ,020801 environmental engineering ,0105 earth and related environmental sciences - Abstract
Record-breaking droughts and high temperatures in 2015 across the Pacific Northwest, USA, provide an opportunistic glimpse into potential future thermal regimes of rivers and their implications for freshwater fishes. We applied spatial stream network models to data collected every 30 min for 4 years at 42 sites on the Snoqualmie River (Washington, United States) to compare water temperature patterns, summarized with relevance to particular life stages of native and nonnative fishes, in 2015 with more typical conditions (2012–2014). Although 2015 conditions were drier and warmer than what had been observed since 1960, patterns were neither consistent over the year nor on the network. Some locations showed dramatic increases in air and water temperature, whereas others had temperatures that differed little from typical years; these results contrasted with existing forecasts of future thermal landscapes. If we will observe years like 2015 more frequently in the future, we can expect conditions to be less favorable to native, cool-water fishes such as Chinook salmon (Oncorhynchus tshawytscha) and bull trout (Salvelinus confluentus) but beneficial to warm-water nonnative species such as largemouth bass (Micropterus salmoides).
- Published
- 2019
5. Impacts of Climate Change on Regulated Streamflow, Hydrologic Extremes, Hydropower Production, and Sediment Discharge in the Skagit River Basin
- Author
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Se-Yeun Lee, Alan F. Hamlet, and Eric E. Grossman
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Hydrology ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Flood myth ,business.industry ,0208 environmental biotechnology ,Drainage basin ,Climate change ,02 engineering and technology ,Structural basin ,01 natural sciences ,020801 environmental engineering ,Current (stream) ,Flow conditions ,Streamflow ,Environmental science ,business ,Ecology, Evolution, Behavior and Systematics ,Hydropower ,0105 earth and related environmental sciences - Abstract
Previous studies have shown that the impacts of climate change on the hydrologic response of the Skagit River are likely to be substantial under natural (i.e. unregulated) conditions. To assess the combined effects of changing natural flow and dam operations that determine impacts to regulated flow, a new integrated daily-time-step reservoir operations model was constructed for the Skagit River Basin. The model was used to simulate current reservoir operating policies for historical flow conditions and for projected flows for the 2040s (2030–2059) and 2080s (2070–2099). The results show that climate change is likely to cause substantial seasonal changes in both natural and regulated flow, with more flow in the winter and spring, and less in summer. Hydropower generation in the basin follows these trends, increasing (+ 19%) in the winter/ spring, and decreasing (- 29%) in the summer by the 2080s. The regulated 100-year flood is projected to increase by 23% by the 2040s and 49% by the 2080s. Peak w...
- Published
- 2016
6. Combined Effects of Projected Sea Level Rise, Storm Surge, and Peak River Flows on Water Levels in the Skagit Floodplain
- Author
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Eric E. Grossman, Se-Yeun Lee, Joseph Hamman, Alan F. Hamlet, and Roger Nathan Fuller
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Hydrology ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Floodplain ,Flood myth ,0208 environmental biotechnology ,Storm surge ,Storm ,Hydrograph ,02 engineering and technology ,01 natural sciences ,020801 environmental engineering ,Current (stream) ,Weather Research and Forecasting Model ,Environmental science ,Climate model ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences - Abstract
Current understanding of the combined effects of sea level rise (SLR), storm surge, and changes in river flooding on near-coastal environments is very limited. This project uses a suite of numerical models to examine the combined effects of projected future climate change on flooding in the Skagit floodplain and estuary. Statistically and dynamically downscaled global climate model scenarios from the ECHAM-5 GCM were used as the climate forcings. Unregulated daily river flows were simulated using the VIC hydrology model, and regulated river flows were simulated using the SkagitSim reservoir operations model. Daily tidal anomalies (TA) were calculated using a regression approach based on ENSO and atmospheric pressure forcing simulated by the WRF regional climate model. A 2-D hydrodynamic model was used to estimate water surface elevations in the Skagit floodplain using resampled hourly hydrographs keyed to regulated daily flood flows produced by the reservoir simulation model, and tide predictions...
- Published
- 2016
7. Projecting spatiotemporally explicit effects of climate change on stream temperature: A model comparison and implications for coldwater fishes
- Author
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Aimee H. Fullerton, Christian E. Torgersen, Se Yeun Lee, and Ning Sun
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Hydrology ,Watershed ,010504 meteorology & atmospheric sciences ,0207 environmental engineering ,Climate change ,02 engineering and technology ,Snowpack ,01 natural sciences ,Spatial heterogeneity ,Habitat ,Effects of global warming ,Streamflow ,Spatial ecology ,Environmental science ,020701 environmental engineering ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Conservation planners and resource managers seek information about how the availability and locations of cold-water habitats will change in the future and how these predictions vary among models. We used a physical process-based model to demonstrate the implications of climate change for streamflow and water temperature in two watersheds with distinctive flow regimes: the Snoqualmie watershed (WA) and Siletz watershed (OR), USA. Our model incorporated a downscaled ensemble of global climate model outputs and was calibrated with in situ and remotely sensed water temperatures. We compared predictions from our processed-based model to those from a publicly available and widely used statistical model. The process-based model projected greater changes in summer maximum water temperatures for the mixed-rain-snow Snoqualmie watershed than for the rain-dominated Siletz watershed as a result of the near-complete loss of winter snowpack and significant reduction in summer flow in the Snoqualmie watershed expected by the 2080s. Both models projected generally similar future spatial patterns of maximum water temperature in the two rivers, with cool reaches distributed farther upstream and fewer in number. However, the process-based model projected higher spatial heterogeneity in water temperature due to our spatially explicit simulation of streamflow and because we calibrated the model with spatially continuous remotely sensed water temperature data. We used stream temperature projections to assess the vulnerability of Pacific salmon and trout to changes in the spatial distribution of cold-water habitats during August by the 2080 s. Results suggest that salmonids may have fewer summertime cold-water habitats in both watersheds. Projected stream warming may further limit particular species and life stages, especially in the Snoqualmie watershed. Our comparison of models highlights the importance of considering what might be gained by using a process-based model for evaluating and prioritizing management actions that mitigate climate impacts on cold-water habitats for stream fishes.
- Published
- 2020
8. Longitudinal thermal heterogeneity in rivers and refugia for coldwater species: effects of scale and climate change
- Author
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Joseph L. Ebersole, E. A. Steel, Se-Yeun Lee, Aimee H. Fullerton, Joshua J. Lawler, and Christian E. Torgersen
- Subjects
Hydrology ,Fish migration ,010504 meteorology & atmospheric sciences ,Ecology ,0208 environmental biotechnology ,Climate change ,02 engineering and technology ,Aquatic Science ,01 natural sciences ,Article ,020801 environmental engineering ,Aquatic organisms ,Water temperature ,Thermal ,Spatial ecology ,Warm water ,Environmental science ,Physical geography ,Scale (map) ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Climate-change driven increases in water temperature pose challenges for aquatic organisms. Predictions of impacts typically do not account for fine-grained spatiotemporal thermal patterns in rivers. Patches of cooler water could serve as refuges for anadromous species like salmon that migrate during summer. We used high-resolution remotely sensed water temperature data to characterize summer thermal heterogeneity patterns for 11,308 km of 2nd- to 7th-order rivers throughout the Pacific Northwest and northern California (USA). We evaluated (1) water temperature patterns at different spatial resolutions, (2) the frequency, size, and spacing of cool thermal patches suitable for Pacific salmon (i.e., contiguous stretches ≥0.25 km, ≤15°C and ≥2°C cooler than adjacent water), and (3) potential influences of climate change on availability of cool patches. Thermal heterogeneity was nonlinearly related to the spatial resolution of water temperature data, and heterogeneity at fine resolution (2.7 and 5.7 and
- Published
- 2018
9. Comparing Large-Scale Hydrological Model Predictions with Observed Streamflow in the Pacific Northwest: Effects of Climate and Groundwater*
- Author
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Guillaume S. Mauger, Alan F. Hamlet, Se-Yeun Lee, Mohammad Safeeq, Gordon E. Grant, and Ivan Arismendi
- Subjects
Hydrology ,Atmospheric Science ,Percentile ,Streamflow ,Hydrological modelling ,Nonparametric statistics ,Range (statistics) ,Environmental science ,Precipitation ,Groundwater ,Rank correlation - Abstract
Assessing uncertainties in hydrologic models can improve accuracy in predicting future streamflow. Here, simulated streamflows using the Variable Infiltration Capacity (VIC) model at coarse (°) and fine (°) spatial resolutions were evaluated against observed streamflows from 217 watersheds. In particular, the adequacy of VIC simulations in groundwater- versus runoff-dominated watersheds using a range of flow metrics relevant for water supply and aquatic habitat was examined. These flow metrics were 1) total annual streamflow; 2) total fall, winter, spring, and summer season streamflows; and 3) 5th, 25th, 50th, 75th, and 95th flow percentiles. The effect of climate on model performance was also evaluated by comparing the observed and simulated streamflow sensitivities to temperature and precipitation. Model performance was evaluated using four quantitative statistics: nonparametric rank correlation ρ, normalized Nash–Sutcliffe efficiency NNSE, root-mean-square error RMSE, and percent bias PBIAS. The VIC model captured the sensitivity of streamflow for temperature better than for precipitation and was in poor agreement with the corresponding temperature and precipitation sensitivities derived from observed streamflow. The model was able to capture the hydrologic behavior of the study watersheds with reasonable accuracy. Both total streamflow and flow percentiles, however, are subject to strong systematic model bias. For example, summer streamflows were underpredicted (PBIAS = −13%) in groundwater-dominated watersheds and overpredicted (PBIAS = 48%) in runoff-dominated watersheds. Similarly, the 5th flow percentile was underpredicted (PBIAS = −51%) in groundwater-dominated watersheds and overpredicted (PBIAS = 19%) in runoff-dominated watersheds. These results provide a foundation for improving model parameterization and calibration in ungauged basins.
- Published
- 2014
10. Estimates of Twenty-First-Century Flood Risk in the Pacific Northwest Based on Regional Climate Model Simulations
- Author
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Eric P. Salathé, Se-Yeun Lee, Matt Stumbaugh, Clifford F. Mass, Alan F. Hamlet, and Richard Steed
- Subjects
Atmospheric Science ,geography ,geography.geographical_feature_category ,Flood myth ,Climatology ,Global warming ,Drainage basin ,Environmental science ,Climate change ,Climate model ,Storm ,Snow ,Downscaling - Abstract
Results from a regional climate model simulation show substantial increases in future flood risk (2040–69) in many Pacific Northwest river basins in the early fall. Two primary causes are identified: 1) more extreme and earlier storms and 2) warming temperatures that shift precipitation from snow to rain dominance over regional terrain. The simulations also show a wide range of uncertainty among different basins stemming from localized storm characteristics. While previous research using statistical downscaling suggests that many areas in the Pacific Northwest are likely to experience substantial increases in flooding in response to global climate change, these initial estimates do not adequately represent the effects of changes in heavy precipitation. Unlike statistical downscaling techniques applied to global climate model scenarios, the regional model provides an explicit, physically based simulation of the seasonality, size, location, and intensity of historical and future extreme storms, including atmospheric rivers. This paper presents climate projections from the ECHAM5/Max Planck Institute Ocean Model (MPI-OM) global climate model dynamically downscaled using the Weather Research and Forecasting (WRF) Model implemented at 12-km resolution for the period 1970–2069. The resulting daily precipitation and temperature data are bias corrected and used as input to a physically based Variable Infiltration Capacity (VIC) hydrologic model. From the daily time step simulations of streamflow produced by the hydrologic model, probability distributions are fit to the extreme events extracted from each water year and flood statistics for various return intervals are estimated.
- Published
- 2014
11. Impacts of 21st-Century Climate Change on Hydrologic Extremes in the Pacific Northwest Region of North America
- Author
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Ingrid Tohver, Alan F. Hamlet, and Se-Yeun Lee
- Subjects
Ecology ,Hydrological modelling ,Climatology ,Evapotranspiration ,Environmental science ,Climate change ,Precipitation ,Structural basin ,Snowpack ,Snow ,Arid ,Earth-Surface Processes ,Water Science and Technology - Abstract
Climate change projections for the Pacific Northwest (PNW) region of North America include warmer temperatures (T), reduced precipitation (P) in summer months, and increased P during all other seasons. Using a physically based hydrologic model and an ensemble of statistically downscaled global climate model scenarios produced by the Columbia Basin Climate Change Scenarios Project, we examine the nature of changing hydrologic extremes (floods and low flows) under natural conditions for about 300 river locations in the PNW. The combination of warming, and shifts in seasonal P regimes, results in increased flooding and more intense low flows for most of the basins in the PNW. Flood responses depend on average midwinter T and basin type. Mixed rain and snow basins, with average winter temperatures near freezing, typically show the largest increases in flood risk because of the combined effects of warming (increasing contributing basin area) and more winter P. Decreases in low flows are driven by loss of snowpack, drier summers, and increasing evapotranspiration in the simulations. Energy-limited basins on the west side of the Cascades show the strongest declines in low flows, whereas more arid, water-limited basins on the east side of the Cascades show smaller reductions in low flows. A fine-scale analysis of hydrologic extremes over the Olympic Peninsula echoes the results for the larger rivers discussed above, but provides additional detail about topographic gradients.
- Published
- 2014
12. An Overview of the Columbia Basin Climate Change Scenarios Project: Approach, Methods, and Summary of Key Results
- Author
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Se-Yeun Lee, Robert A. Norheim, Alan F. Hamlet, Marketa M. Elsner, Ingrid Tohver, and Guillaume S. Mauger
- Subjects
Atmospheric Science ,Data processing ,geography ,Decision support system ,Geographic information system ,geography.geographical_feature_category ,business.industry ,Environmental resource management ,Drainage basin ,Climate change ,Structural basin ,Oceanography ,Climatology ,Environmental science ,Climate model ,business ,Downscaling - Abstract
The Columbia Basin Climate Change Scenarios Project (CBCCSP) was conceived as a comprehensive hydrologic database to support climate change planning, impacts assessment, and adaptation in the Pacific Northwest (PNW) by a diverse user community with varying technical capacity over a wide range of spatial scales. The study has constructed a state-of-the-art, end-to-end data processing sequence from “raw” climate model output to a suite of hydrologic modelling products that are served to the user community from a web-accessible database. A calibrated 1/16 degree latitude-longitude resolution implementation of the VIC hydrologic model over the Columbia River basin was used to produce historical simulations and 77 future hydrologic projections associated with three different statistical downscaling methods and three future time periods (2020s, 2040s, and 2080s). Key products from the study include summary data for about 300 river locations in the PNW and monthly Geographic Information System products for 21 hy...
- Published
- 2013
13. RF Circuit Design for IEEE 802.11p Implementation
- Author
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Se-Yeun Lee and Myung-Ho Lee
- Subjects
IEEE 802.11u ,Engineering ,IEEE 802.11b-1999 ,IEEE 802.11w-2009 ,Inter-Access Point Protocol ,business.industry ,Electronic engineering ,IEEE 802.11g-2003 ,IEEE 802.11p ,business ,IEEE 802.11a-1999 ,IEEE 802.11s - Abstract
The WAVE specification, which for the Next-Generation ITS environment is a common title: IEEE 802.11p and IEEE P1609 specifications. These days, there are many activities for researching WAVE specification by release of the IEEE 802.11p specification. The difference between high-speed vehicle environment and the indoor environment, the wireless communication channel mode is that much more severe. Thus, the wireless communication system design, temperature, noise, multipath fading and can degrade the performance of the system points should be fully considered matters of. In this paper, we showed WAVE wireless communication system which based on IEEE 802.11p PHY/MAC design process, and also showed solving process many implementation problems.
- Published
- 2012
14. Daily Time-Step Refinement of Optimized Flood Control Rule Curves for a Global Warming Scenario
- Author
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Carolyn J. Fitzgerald, Se-Yeun Lee, Alan F. Hamlet, and Stephen J. Burges
- Subjects
geography ,geography.geographical_feature_category ,Meteorology ,Hydrological modelling ,Geography, Planning and Development ,Global warming ,Simulation modeling ,Drainage basin ,Climate change ,Management, Monitoring, Policy and Law ,Water resources ,Flood control ,Climatology ,Streamflow ,Environmental science ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Pacific Northwest temperatures have warmed by 0.8°C since 1920 and are predicted to increase in the 21st century. Streamflow timing shifts associated with climate change would degrade the water resources system performance for climate change scenarios using existing system operation policies for the Columbia River Basin. To mitigate the hydrologic impacts of anticipated climate change on this complex water resource system, optimized flood control operating rule curves were developed at a monthly time step in a previous study and were evaluated with a monthly time-step simulation model. Here, a daily time-step simulation model is used over a smaller portion of the domain to evaluate and refine the optimized flood-control curves derived from monthly time-step analysis. Daily time-step simulations demonstrate that maximum evacuation targets for flood control derived from the monthly analysis were remarkably robust. However, the evacuation schedules for Libby and Duncan Dams from February to April conflicted ...
- Published
- 2011
15. Methodology for Developing Flood Rule Curves Conditioned on El Niño-Southern Oscillation Classification1
- Author
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Stephen J. Burges, Alan F. Hamlet, Se-Yeun Lee, and Carolyn J. Fitzgerald
- Subjects
Hydrology ,Ecology ,Flood myth ,Flood forecasting ,Structural basin ,Current (stream) ,Flood control ,Water resources ,Streamflow ,100-year flood ,Environmental science ,Water resource management ,Earth-Surface Processes ,Water Science and Technology - Abstract
Lee, Se-Yeun, Alan F. Hamlet, Carolyn J. Fitzgerald, and Stephen J. Burges, 2011. Methodology for Developing Flood Rule Curves Conditioned on El Nino-Southern Oscillation Classification. Journal of the American Water Resources Association (JAWRA) 47(1):81-92. DOI: 10.1111/j.1752-1688.2010.00490.x Abstract: Regional climate varies on interannual and decadal time scales that in turn affect annual streamflows, flood risks, and reservoir storage deficits in mid-summer. However, these variable elements of the climate system are generally not included in water resources operating policies that attempt to preserve a balance between flood risk and other water resources system objectives. A methodology for incorporating El Nino-Southern Oscillation (ENSO) information in designing flood control curves is investigated. An optimization-simulation procedure is used to develop a set of ENSO-conditioned flood control rule curves that relate streamflow forecasts to flood control evacuation requirements. ENSO-conditioned simulated flood risk and storage deficits under current operating policy are used to calibrate a unique objective function for each ENSO classification. Using a case study for the Columbia River Basin, we demonstrate that ENSO-conditioned flood control curves constructed using the optimization-simulation procedure consistently reduce storage deficits at a number of interrelated projects without increasing flood risk. For the Columbia Basin, the overall improvements in reservoir operations are relatively modest, and (in isolation) might not motivate a restructuring of flood control operations. However, the technique is widely applicable to a wide range of water resources systems and/or different climate indices.
- Published
- 2010
16. Effects of projected climate change on energy supply and demand in the Pacific Northwest and Washington State
- Author
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Marketa M. Elsner, Kristian E. B. Mickelson, Alan F. Hamlet, and Se-Yeun Lee
- Subjects
Atmospheric Science ,Global and Planetary Change ,education.field_of_study ,Meteorology ,business.industry ,Population ,Climate change ,Seasonality ,medicine.disease ,Atmospheric sciences ,Effects of global warming ,Air conditioning ,Per capita ,medicine ,Environmental science ,business ,education ,Heating degree day ,Hydropower - Abstract
Climate strongly affects energy supply and demand in the Pacific Northwest (PNW) and Washington State (WA). We evaluate potential effects of climate change on the seasonality and annual amount of PNW hydropower production, and on heating and cooling energy demand. Changes in hydropower production are estimated by linking simulated streamflow scenarios produced by a hydrology model to a simulation model of the Columbia River hydro system. Changes in energy demand are assessed using gridded estimates of heating degree days (HDD) and cooling degree days (CDD) which are then combined with population projections to create energy demand indices that respond both to climate, future population, and changes in residential air conditioning market penetration. We find that substantial changes in the amount and seasonality of energy supply and demand in the PNW are likely to occur over the next century in response to warming, precipitation changes, and population growth. By the 2040s hydropower production is projected to increase by 4.7–5.0% in winter, decrease by about 12.1–15.4% in summer, with annual reductions of 2.0–3.4%. Larger decreases of 17.1–20.8% in summer hydropower production are projected for the 2080s. Although the combined effects of population growth and warming are projected to increase heating energy demand overall (22–23% for the 2020s, 35–42% for the 2040s, and 56–74% for the 2080s), warming results in reduced per capita heating demand. Residential cooling energy demand (currently less than one percent of residential demand) increases rapidly (both overall and per capita) to 4.8–9.1% of the total demand by the 2080s due to increasing population, cooling degree days, and air conditioning penetration.
- Published
- 2010
17. Implications of 21st century climate change for the hydrology of Washington State
- Author
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Julie A. Vano, Marketa M. Elsner, Alan F. Hamlet, Se-Yeun Lee, Lan Cuo, Dennis P. Lettenmaier, Kristian E. B. Mickelson, Jeffrey S. Deems, and Nathalie Voisin
- Subjects
Hydrology ,Atmospheric Science ,Global and Planetary Change ,Hydrology (agriculture) ,Climatology ,Streamflow ,Snowmelt ,Environmental science ,Climate change ,Climate model ,Precipitation ,Snow ,Surface runoff - Abstract
Pacific Northwest (PNW) hydrology is particularly sensitive to changes in climate because snowmelt dominates seasonal runoff, and temperature changes impact the rain/snow balance. Based on results from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), we updated previous studies of implications of climate change on PNW hydrology. PNW 21st century hydrology was simulated using 20 Global Climate Models (GCMs) and 2 greenhouse gas emissions scenarios over Washington and the greater Columbia River watershed, with additional focus on the Yakima River watershed and the Puget Sound which are particularly sensitive to climate change. We evaluated projected changes in snow water equivalent (SWE), soil moisture, runoff, and streamflow for A1B and B1 emissions scenarios for the 2020s, 2040s, and 2080s. April 1 SWE is projected to decrease by approximately 38–46% by the 2040s (compared with the mean over water years 1917–2006), based on composite scenarios of B1 and A1B, respectively, which represent average effects of all climate models. In three relatively warm transient watersheds west of the Cascade crest, April 1 SWE is projected to almost completely disappear by the 2080s. By the 2080s, seasonal streamflow timing will shift significantly in both snowmelt dominant and rain–snow mixed watersheds. Annual runoff across the State is projected to increase by 2–3% by the 2040s; these changes are mainly driven by projected increases in winter precipitation.
- Published
- 2010
18. Optimized Flood Control in the Columbia River Basin for a Global Warming Scenario
- Author
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Alan F. Hamlet, Se-Yeun Lee, Stephen J. Burges, and Carolyn J. Fitzgerald
- Subjects
Hydrology ,geography ,geography.geographical_feature_category ,Hydrological modelling ,Geography, Planning and Development ,Flood forecasting ,Global warming ,Drainage basin ,Context (language use) ,Management, Monitoring, Policy and Law ,Flood control ,Current (stream) ,Snowmelt ,Environmental science ,Water Science and Technology ,Civil and Structural Engineering - Abstract
Anticipated future temperature changes in the mountainous U.S. Pacific Northwest will cause reduced spring snow pack, earlier melt, earlier spring peak flow and lower summer flow in transient rain-snow and snowmelt dominant river basins. In the context of managed flood control, these systematic changes are likely to disrupt the balance between flood control and reservoir refill in existing reservoir systems. To adapt to these hydrologic changes, refill timing and evacuation requirements for flood control need to be modified. This work poses a significant systems engineering problem, especially for large, multiobjective water systems. An existing optimization/simulation procedure is refined for rebalancing flood control and refill objectives for the Columbia River Basin for anticipated global warming. To calibrate the optimization model for the 20th century flow, the objective function is tuned to reproduce the current reliability of reservoir refill, while providing comparable levels of flood control to t...
- Published
- 2009
19. Optimized Flood Control in the Columbia River Basin for a Global Warming Scenario
- Author
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Stephen J. Burges, Carolyn J. Fitzgerald, Dennis P. Lettenmaier, Se-Yeun Lee, and Alan F. Hamlet
- Subjects
Flood control ,Hydrology ,geography ,geography.geographical_feature_category ,Global warming ,Drainage basin ,Environmental science - Published
- 2006
20. Optimized Flood Control in the Columbia River Basin for a Global Warming Scenario.
- Author
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Se-Yeun Lee, Hamlet, Alan F., Fitzgerald, Carolyn J., Burges, Stephen J., and Lettenmaier, Dennis P.
- Published
- 2006
- Full Text
- View/download PDF
21. Effects of projected climate change on energy supply and demand in the Pacific Northwest and Washington State.
- Author
-
Hamlet, Alan F., Se-Yeun Lee, Mickelson, Kristian E. B., and Elsner, Marketa M.
- Subjects
SUPPLY & demand ,CLIMATE change ,WATER power ,ATMOSPHERIC temperature - Abstract
Climate strongly affects energy supply and demand in the Pacific Northwest (PNW) and Washington State (WA). We evaluate potential effects of climate change on the seasonality and annual amount of PNW hydropower production, and on heating and cooling energy demand. Changes in hydropower production are estimated by linking simulated streamflow scenarios produced by a hydrology model to a simulation model of the Columbia River hydro system. Changes in energy demand are assessed using gridded estimates of heating degree days (HDD) and cooling degree days (CDD) which are then combined with population projections to create energy demand indices that respond both to climate, future population, and changes in residential air conditioning market penetration. We find that substantial changes in the amount and seasonality of energy supply and demand in the PNW are likely to occur over the next century in response to warming, precipitation changes, and population growth. By the 2040s hydropower production is projected to increase by 4.7–5.0% in winter, decrease by about 12.1–15.4% in summer, with annual reductions of 2.0–3.4%. Larger decreases of 17.1–20.8% in summer hydropower production are projected for the 2080s. Although the combined effects of population growth and warming are projected to increase heating energy demand overall (22–23% for the 2020s, 35–42% for the 2040s, and 56–74% for the 2080s), warming results in reduced per capita heating demand. Residential cooling energy demand (currently less than one percent of residential demand) increases rapidly (both overall and per capita) to 4.8–9.1% of the total demand by the 2080s due to increasing population, cooling degree days, and air conditioning penetration. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
22. Implications of 21st century climate change for the hydrology of Washington State.
- Author
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Elsner, Marketa M., Lan Cuo, Voisin, Nathalie, Deems, Jeffrey S., Hamlet, Alan F., Vano, Julie A., Mickelson, Kristian E. B., Se-Yeun Lee, and Lettenmaier, Dennis P.
- Subjects
CLIMATE change ,HYDROGRAPHY ,STREAMFLOW ,GREENHOUSE gas mitigation ,SNOWMELT - Abstract
Pacific Northwest (PNW) hydrology is particularly sensitive to changes in climate because snowmelt dominates seasonal runoff, and temperature changes impact the rain/snow balance. Based on results from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), we updated previous studies of implications of climate change on PNW hydrology. PNW 21st century hydrology was simulated using 20 Global Climate Models (GCMs) and 2 greenhouse gas emissions scenarios over Washington and the greater Columbia River watershed, with additional focus on the Yakima River watershed and the Puget Sound which are particularly sensitive to climate change. We evaluated projected changes in snow water equivalent (SWE), soil moisture, runoff, and streamflow for A1B and B1 emissions scenarios for the 2020s, 2040s, and 2080s. April 1 SWE is projected to decrease by approximately 38–46% by the 2040s (compared with the mean over water years 1917–2006), based on composite scenarios of B1 and A1B, respectively, which represent average effects of all climate models. In three relatively warm transient watersheds west of the Cascade crest, April 1 SWE is projected to almost completely disappear by the 2080s. By the 2080s, seasonal streamflow timing will shift significantly in both snowmelt dominant and rain–snow mixed watersheds. Annual runoff across the State is projected to increase by 2–3% by the 2040s; these changes are mainly driven by projected increases in winter precipitation. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
23. Optimized Flood Control in the Columbia River Basin for a Global Warming Scenario.
- Author
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Se-Yeun Lee, Hamlet, Alan F., Fitzgerald, Carolyn J., and Burges, Stephen J.
- Subjects
- *
FLOOD control , *CLIMATE change , *WATERSHEDS , *GLOBAL warming , *HYDROLOGIC models - Abstract
Anticipated future temperature changes in the mountainous U.S. Pacific Northwest will cause reduced spring snow pack, earlier melt, earlier spring peak flow and lower summer flow in transient rain-snow and snowmelt dominant river basins. In the context of managed flood control, these systematic changes are likely to disrupt the balance between flood control and reservoir refill in existing reservoir systems. To adapt to these hydrologic changes, refill timing and evacuation requirements for flood control need to be modified. This work poses a significant systems engineering problem, especially for large, multiobjective water systems. An existing optimization/simulation procedure is refined for rebalancing flood control and refill objectives for the Columbia River Basin for anticipated global warming. To calibrate the optimization model for the 20th century flow, the objective function is tuned to reproduce the current reliability of reservoir refill, while providing comparable levels of flood control to those produced by current flood control practices. After the optimization model is calibrated using the 20th century flow the same objective function is used to develop flood control curves for a global warming scenario which assumes an approximately 2°C increase in air temperature. Robust decreases in system storage deficits are simulated for the climate change scenario when optimized flood rule curves replace the current flood control curves, without increasing monthly flood risks. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
24. Peer review report 1 On 'The influence of climate modes on streamflow in the Mid-Atlantic region of the United States'
- Author
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Se-Yeun Lee
- Subjects
Geography ,Mid-Atlantic Region ,Streamflow ,Climatology ,Earth and Planetary Sciences (miscellaneous) ,Water Science and Technology - Full Text
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