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• 21. [Article] A Comparative Assessment of Projected Meteorological and Hydrological Droughts: Elucidating the Role of Temperature

  The changing climate and the associated future increases in temperature are expected to have impacts on drought characteristics and hydrologic cycle. This paper investigates the projected changes in spatiotemporal ...

  Citation × Citation Citation Abstract Copy Title: A Comparative Assessment of Projected Meteorological and Hydrological Droughts: Elucidating the Role of Temperature Author: Ahmadalipour, Ali, Moradkhani, Hamid, Demirel, Mehmet C. Year: 2017 The changing climate and the associated future increases in temperature are expected to have impacts on drought characteristics and hydrologic cycle. This paper investigates the projected changes in spatiotemporal characteristics of droughts and their future attributes over the Willamette River Basin (WRB) in the Pacific Northwest U.S. The analysis is performed using two subsets of downscaled CMIP5 global climate models (GCMs) each consisting of 10 models from two future scenarios (RCP4.5 and RCP8.5) for 30 years of historical period (1970–1999) and 90 years of future projections (2010–2099). Hydrologic modeling is conducted using the Precipitation Runoff Modeling System (PRMS) as a robust distributed hydrologic model with lower computational cost compared to other models. Meteorological and hydrological droughts are studied using three drought indices (i.e. Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, Standardized Streamflow Index). Results reveal that the intensity and duration of hydrological droughts are expected to increase over the WRB, albeit the annual precipitation is expected to increase. On the other hand, the intensity of meteorological droughts do not indicate an aggravation for most cases. We explore the changes of hydrometeolorogical variables over the basin in order to understand the causes for such differences and to discover the controlling factors of drought. Furthermore, the uncertainty of projections are quantified for model, scenario, and downscaling uncertainty. Title: A Comparative Assessment of Projected Meteorological and Hydrological Droughts: Elucidating the Role of Temperature Author: Ahmadalipour, Ali, Moradkhani, Hamid, Demirel, Mehmet C. Year: 2017 The changing climate and the associated future increases in temperature are expected to have impacts on drought characteristics and hydrologic cycle. This paper investigates the projected changes in spatiotemporal characteristics of droughts and their future attributes over the Willamette River Basin (WRB) in the Pacific Northwest U.S. The analysis is performed using two subsets of downscaled CMIP5 global climate models (GCMs) each consisting of 10 models from two future scenarios (RCP4.5 and RCP8.5) for 30 years of historical period (1970–1999) and 90 years of future projections (2010–2099). Hydrologic modeling is conducted using the Precipitation Runoff Modeling System (PRMS) as a robust distributed hydrologic model with lower computational cost compared to other models. Meteorological and hydrological droughts are studied using three drought indices (i.e. Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, Standardized Streamflow Index). Results reveal that the intensity and duration of hydrological droughts are expected to increase over the WRB, albeit the annual precipitation is expected to increase. On the other hand, the intensity of meteorological droughts do not indicate an aggravation for most cases. We explore the changes of hydrometeolorogical variables over the basin in order to understand the causes for such differences and to discover the controlling factors of drought. Furthermore, the uncertainty of projections are quantified for model, scenario, and downscaling uncertainty. Close

• 22. [Article] Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the American ...

  Citation × Citation Citation Abstract Copy Title: Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses Author: Roberts-Jones, Jonah, Martin, Matthew J., Menemenlis, Dimitris, Merchant, Christopher John, Chelton, Dudley B., Reynolds, Richard W. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the American Meteorological Society and can be found at: http://www.ametsoc.org/pubs/journals/jcli/. Title: Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses Author: Roberts-Jones, Jonah, Martin, Matthew J., Menemenlis, Dimitris, Merchant, Christopher John, Chelton, Dudley B., Reynolds, Richard W. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the American Meteorological Society and can be found at: http://www.ametsoc.org/pubs/journals/jcli/. Close

• 23. [Article] Specific consensus statement on the likely impacts of climate change on the Pacific Northwest

  The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s ...

  Citation × Citation Citation Abstract Copy Title: Specific consensus statement on the likely impacts of climate change on the Pacific Northwest The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s Advisory Group on Global Warming in its task of developing a greenhouse gas emission reduction strategy for Oregon. The signatories agree that climate change is underway and that it is having global effects as well as impacts in the Pacific Northwest region. Title: Specific consensus statement on the likely impacts of climate change on the Pacific Northwest The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s Advisory Group on Global Warming in its task of developing a greenhouse gas emission reduction strategy for Oregon. The signatories agree that climate change is underway and that it is having global effects as well as impacts in the Pacific Northwest region. Close

• 24. [Article] A METHOD FOR ANALYSING CLIMATE IN TERMS OF ARCHITECTURAL RESPONSES

  4 p.

  Citation × Citation Citation Abstract Copy Title: A METHOD FOR ANALYSING CLIMATE IN TERMS OF ARCHITECTURAL RESPONSES Author: Brown, G. Z., Novitski, B. J. Year: 2011 4 p. Title: A METHOD FOR ANALYSING CLIMATE IN TERMS OF ARCHITECTURAL RESPONSES Author: Brown, G. Z., Novitski, B. J. Year: 2011 4 p. Close

• 25. [Article] Climate Change Effects and Water Vulnerability in the Molalla Pudding River Basin, Oregon, USA

  Water management plans are typically developed using historical data records and historical return periods for extreme events, such as floods or droughts. Since these analyses of return periods typically ...

  Citation × Citation Citation Abstract Copy Title: Climate Change Effects and Water Vulnerability in the Molalla Pudding River Basin, Oregon, USA Author: Wherry, Susan Amelia Year: 2012 Water management plans are typically developed using historical data records and historical return periods for extreme events, such as floods or droughts. Since these analyses of return periods typically assume a certain degree of stationarity (constant mean, standard deviation, distribution) in hydrologic variables, the potential future impacts of climate change are excluded. In developing water management plans, predicted changes to climate variables should be considered to evaluate the degree of non-stationarity that may exist in the future. In this way, regions most sensitive to climate change can be identified and managed appropriately. This study performed such a task by using predicted climate data that were downscaled from general circulation models (GCM) by regional climate models (RCM) to compare climate variables in the historical period of 1971-1998 to the future period of 2041-2068. The study evaluated the precipitation and minimum/maximum temperature data from five different GCM/RCM combinations: 1) CCSM/CRCM; 2) CCSM/WRFG; 3) CGCM3/CRCM; 4) CGCM3/WRFG; and 5) HadCM3/HRM3. The five datasets were then used to calculate drought indices and drive a calibrated PRMS model of the Molalla Pudding river basin in order to evaluate changes in droughts and streamflow. The predicted changes in droughts and streamflow were then evaluated with social/economic factors for twelve cities in the Molalla Pudding river basin by two different water vulnerability indices. The index values were used to determine a rank for each city that indicated its relative vulnerability to water scarcity as compared to the other cities. In this study, three out of the five datasets predicted increased precipitation (+97-115 mm/year) over the Molalla Pudding basin and the two datasets using the CCSM GCM data predicted either no change or slightly decreased precipitation (-60 mm/year) over the Molalla Pudding basin in 2041-2068. All datasets predicted increased minimum and maximum average temperature of +1.5°C and +1.4°C respectively, and all datasets displayed increasing trends in temperature. The drought indices predicted fewer drought events (-2.4 events) over 2041-2068 with no change in duration, and no change to the number of serious drought events over 2041-2068 but with increased durations (+1.9 months). Results from the hydrologic modeling predicted increased streamflow (+4-249 cfs) in four out of the five future datasets. Using the predicted changes in hydrologic variables and social/economic census data from 2000, two types of water vulnerability indices were calculated for the twelve cities of interest. The results suggested that cities in the western portion of the basin would be more susceptible to current and future water vulnerability due to high irrigation demands for water and high social vulnerability as determined by minority populations and higher poverty, while the small cities with less dependence on agriculture would be less vulnerable. Title: Climate Change Effects and Water Vulnerability in the Molalla Pudding River Basin, Oregon, USA Author: Wherry, Susan Amelia Year: 2012 Water management plans are typically developed using historical data records and historical return periods for extreme events, such as floods or droughts. Since these analyses of return periods typically assume a certain degree of stationarity (constant mean, standard deviation, distribution) in hydrologic variables, the potential future impacts of climate change are excluded. In developing water management plans, predicted changes to climate variables should be considered to evaluate the degree of non-stationarity that may exist in the future. In this way, regions most sensitive to climate change can be identified and managed appropriately. This study performed such a task by using predicted climate data that were downscaled from general circulation models (GCM) by regional climate models (RCM) to compare climate variables in the historical period of 1971-1998 to the future period of 2041-2068. The study evaluated the precipitation and minimum/maximum temperature data from five different GCM/RCM combinations: 1) CCSM/CRCM; 2) CCSM/WRFG; 3) CGCM3/CRCM; 4) CGCM3/WRFG; and 5) HadCM3/HRM3. The five datasets were then used to calculate drought indices and drive a calibrated PRMS model of the Molalla Pudding river basin in order to evaluate changes in droughts and streamflow. The predicted changes in droughts and streamflow were then evaluated with social/economic factors for twelve cities in the Molalla Pudding river basin by two different water vulnerability indices. The index values were used to determine a rank for each city that indicated its relative vulnerability to water scarcity as compared to the other cities. In this study, three out of the five datasets predicted increased precipitation (+97-115 mm/year) over the Molalla Pudding basin and the two datasets using the CCSM GCM data predicted either no change or slightly decreased precipitation (-60 mm/year) over the Molalla Pudding basin in 2041-2068. All datasets predicted increased minimum and maximum average temperature of +1.5°C and +1.4°C respectively, and all datasets displayed increasing trends in temperature. The drought indices predicted fewer drought events (-2.4 events) over 2041-2068 with no change in duration, and no change to the number of serious drought events over 2041-2068 but with increased durations (+1.9 months). Results from the hydrologic modeling predicted increased streamflow (+4-249 cfs) in four out of the five future datasets. Using the predicted changes in hydrologic variables and social/economic census data from 2000, two types of water vulnerability indices were calculated for the twelve cities of interest. The results suggested that cities in the western portion of the basin would be more susceptible to current and future water vulnerability due to high irrigation demands for water and high social vulnerability as determined by minority populations and higher poverty, while the small cities with less dependence on agriculture would be less vulnerable. Close

• 26. [Article] Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States

  Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred ...

  Citation × Citation Citation Abstract Copy Title: Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States Author: Heard, Joshua Andrews Year: 2012 Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude (ELA) of 1995 ± 70 m is ~150 m below the average modern ELA of 2149 ± 76 m. To satisfy climate conditions at the LIA ELA, the winter snow accumulation must have been 8 to 43 cm greater and mean summer temperatures 0.2 to 1.3 ºC cooler than they are now. Late Pleistocene to early Holocene (LPEH) aged moraines are located between 100 and 400 m below the LIA deposits. They have degraded moraine crests, few surface boulders, and considerable vegetation and soil cover. Volcanic ashes indicate LPEH moraines were deposited before 1480 AD while morphometric data suggest deposition during the late Pleistocene or early Holocene. The average LPEH ELA of 1904 ± 110 m is ~ 240 m and ~90 m below the modern and LIA ELAs, respectively. The climate change necessary to maintain a glacier with an ELA at that elevation for LPEH conditions requires the winter accumulation to increase by 47 to 48 cm weq and the mean summer temperature to cool by 1.4 to 1.5 ºC. Last glacial maximum (LGM) moraines are located more than 30 km downstream from modern glacial termini. They are characterized by hummocky topography, rounded moraine crests, complete vegetation cover, and well developed soil cover. Moraine morphometry, soil characteristics, and distance from modern glacial termini indicate that deposition occurred at least 15 ka BP during an expansive cooling event, the last being the LGM. The LGM ELA of 1230 m is ~920 m below the modern ELA. The climate change necessary to maintain a glacier with an ELA at that elevation for LGM conditions requires the mean summer temperature to cool by 5.6 ºC with no change in precipitation. Title: Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States Author: Heard, Joshua Andrews Year: 2012 Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude (ELA) of 1995 ± 70 m is ~150 m below the average modern ELA of 2149 ± 76 m. To satisfy climate conditions at the LIA ELA, the winter snow accumulation must have been 8 to 43 cm greater and mean summer temperatures 0.2 to 1.3 ºC cooler than they are now. Late Pleistocene to early Holocene (LPEH) aged moraines are located between 100 and 400 m below the LIA deposits. They have degraded moraine crests, few surface boulders, and considerable vegetation and soil cover. Volcanic ashes indicate LPEH moraines were deposited before 1480 AD while morphometric data suggest deposition during the late Pleistocene or early Holocene. The average LPEH ELA of 1904 ± 110 m is ~ 240 m and ~90 m below the modern and LIA ELAs, respectively. The climate change necessary to maintain a glacier with an ELA at that elevation for LPEH conditions requires the winter accumulation to increase by 47 to 48 cm weq and the mean summer temperature to cool by 1.4 to 1.5 ºC. Last glacial maximum (LGM) moraines are located more than 30 km downstream from modern glacial termini. They are characterized by hummocky topography, rounded moraine crests, complete vegetation cover, and well developed soil cover. Moraine morphometry, soil characteristics, and distance from modern glacial termini indicate that deposition occurred at least 15 ka BP during an expansive cooling event, the last being the LGM. The LGM ELA of 1230 m is ~920 m below the modern ELA. The climate change necessary to maintain a glacier with an ELA at that elevation for LGM conditions requires the mean summer temperature to cool by 5.6 ºC with no change in precipitation. Close

• 27. [Article] Relationship between tropical Atlantic Sea surface temperature variability and southern Indian Ocean tropical cyclones

  Recent studies have found that equatorial Atlantic sea surface temperature (SST) variability may be influencing tropical Indian Ocean climate (Kucharski 2009, Wang 2009). Due to the economic and social ...

  Citation × Citation Citation Abstract Copy Title: Relationship between tropical Atlantic Sea surface temperature variability and southern Indian Ocean tropical cyclones Author: DeBlander, Evan F. Recent studies have found that equatorial Atlantic sea surface temperature (SST) variability may be influencing tropical Indian Ocean climate (Kucharski 2009, Wang 2009). Due to the economic and social impact of tropical cyclones, it is important to investigate how an Atlantic-Indian Ocean connection may be affecting tropical cyclone behavior in the southern Indian Ocean. In this study, the International Best Track Archive for Climate Stewardship (IBTrAC) tropical cyclone database is used to derive metrics of tropical cyclone behavior, which are then compared with indices of tropical Atlantic SST variability representing Atlantic Niño, and Benguela Niño events. Changes in tropical Atlantic SSTs are found to coincide with significant differences in tropical cyclone activity for portions of the southern Indian Ocean. In addition, for these same regions, tropical Atlantic SST variability is associated with changes in large-scale atmospheric conditions, including steering flow, low level vorticity, and humidity, typically associated with tropical cyclogenesis, and tropical cyclone track. The changes in steering flow related to both indices of Atlantic SST anomaly are reproduced by an atmospheric model. The changes in steering flow are also found to be linked to changes in TC translational velocity, and TC tracking. These findings indicate a possible link between tropical Atlantic conditions and cyclone activity in the Indian Ocean mediated through a teleconnection between tropical Atlantic SSTs and large scale atmospheric conditions over the southern Indian Ocean. The teleconnection related to the Benguela Niño region of SST variability was found to consist of a Rossby wave initiated off the coast of South America, and propagating into the Indian Ocean, thereby influencing several atmospheric variables, including steering flow. The teleconnection related to the Atlantic Niño region of SST variability was not well defined, although there was some evidence of a Walker circulation anomaly extending from the equatorial Atlantic over the continent of Africa, and influencing SIO steering flow. Title: Relationship between tropical Atlantic Sea surface temperature variability and southern Indian Ocean tropical cyclones Author: DeBlander, Evan F. Recent studies have found that equatorial Atlantic sea surface temperature (SST) variability may be influencing tropical Indian Ocean climate (Kucharski 2009, Wang 2009). Due to the economic and social impact of tropical cyclones, it is important to investigate how an Atlantic-Indian Ocean connection may be affecting tropical cyclone behavior in the southern Indian Ocean. In this study, the International Best Track Archive for Climate Stewardship (IBTrAC) tropical cyclone database is used to derive metrics of tropical cyclone behavior, which are then compared with indices of tropical Atlantic SST variability representing Atlantic Niño, and Benguela Niño events. Changes in tropical Atlantic SSTs are found to coincide with significant differences in tropical cyclone activity for portions of the southern Indian Ocean. In addition, for these same regions, tropical Atlantic SST variability is associated with changes in large-scale atmospheric conditions, including steering flow, low level vorticity, and humidity, typically associated with tropical cyclogenesis, and tropical cyclone track. The changes in steering flow related to both indices of Atlantic SST anomaly are reproduced by an atmospheric model. The changes in steering flow are also found to be linked to changes in TC translational velocity, and TC tracking. These findings indicate a possible link between tropical Atlantic conditions and cyclone activity in the Indian Ocean mediated through a teleconnection between tropical Atlantic SSTs and large scale atmospheric conditions over the southern Indian Ocean. The teleconnection related to the Benguela Niño region of SST variability was found to consist of a Rossby wave initiated off the coast of South America, and propagating into the Indian Ocean, thereby influencing several atmospheric variables, including steering flow. The teleconnection related to the Atlantic Niño region of SST variability was not well defined, although there was some evidence of a Walker circulation anomaly extending from the equatorial Atlantic over the continent of Africa, and influencing SIO steering flow. Close

• 28. [Article] Community Earth System Model: Implementation, Validation, and Applications

  The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, ...

  Citation × Citation Citation Abstract Copy Title: Community Earth System Model: Implementation, Validation, and Applications Author: Porter, William Christian Year: 2012 The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older versions of the model. Second, the CESM model is applied to an examination of the effect that increased methane (CH4) concentrations have had on the catalytic destruction of stratospheric ozone (O3) by ozone depleting compounds (ODCs) such as chlorofluorocarbons (CFCs) and nitrous oxide (N2O). Title: Community Earth System Model: Implementation, Validation, and Applications Author: Porter, William Christian Year: 2012 The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older versions of the model. Second, the CESM model is applied to an examination of the effect that increased methane (CH4) concentrations have had on the catalytic destruction of stratospheric ozone (O3) by ozone depleting compounds (ODCs) such as chlorofluorocarbons (CFCs) and nitrous oxide (N2O). Close

• 29. [Article] Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System

  This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future ...

  Citation × Citation Citation Abstract Copy Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System Author: Yazzie, Kimberly Crystal Year: 2016 This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km2, located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration Pathways 4.5 and 8.5 (RCP), were used to observe hydrologic regime shifts in the 2020s, 2050s, and 2080s. Mean center timing of flow occurs earlier in the year in both pre- and post-fire conditions, where there are increased winter flows and decreased summer flows throughout the 21st century. Change in temperature and percent change in precipitation is more variable in the summer than winter increasing over time, with a slight decrease in winter precipitation in the 2080s in RCP 8.5. Temperature increases 1.6°C in RCP 4.5 and 3.3°C in RCP 8.5 by the end of the 21st century. The ratio of Snow Water Equivalent to Precipitation decreases 96% in the 2080s in RCP 8.5 before forest cover reduction, and decreases 90-99% after forest cover reduction. Potential basin recharge and the base-flow index are both sustained throughout the 21st century with slight declines before forest cover reduction, with an increase in basin recharge and increase in base-flows in the 2080s after fire-burns. However, the simulated sustained base-flows and area-weighted basin recharge in this study, do not take into account the complex geologic structure of the Columbia River Basalt Group (CRBG). A more robust characterization and simulation of URB aquifer recharge would involve coupling the PRMS model with a groundwater model in a future study. Although groundwater recharge in the CRBG in the URB is not well understood, the long-term decline of groundwater storage presents a serious environmental challenge for the Confederated Tribes of the Umatilla Indian Reservation and communities in the URB. Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin Using the Precipitation Runoff Modeling System Author: Yazzie, Kimberly Crystal Year: 2016 This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km2, located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration Pathways 4.5 and 8.5 (RCP), were used to observe hydrologic regime shifts in the 2020s, 2050s, and 2080s. Mean center timing of flow occurs earlier in the year in both pre- and post-fire conditions, where there are increased winter flows and decreased summer flows throughout the 21st century. Change in temperature and percent change in precipitation is more variable in the summer than winter increasing over time, with a slight decrease in winter precipitation in the 2080s in RCP 8.5. Temperature increases 1.6°C in RCP 4.5 and 3.3°C in RCP 8.5 by the end of the 21st century. The ratio of Snow Water Equivalent to Precipitation decreases 96% in the 2080s in RCP 8.5 before forest cover reduction, and decreases 90-99% after forest cover reduction. Potential basin recharge and the base-flow index are both sustained throughout the 21st century with slight declines before forest cover reduction, with an increase in basin recharge and increase in base-flows in the 2080s after fire-burns. However, the simulated sustained base-flows and area-weighted basin recharge in this study, do not take into account the complex geologic structure of the Columbia River Basalt Group (CRBG). A more robust characterization and simulation of URB aquifer recharge would involve coupling the PRMS model with a groundwater model in a future study. Although groundwater recharge in the CRBG in the URB is not well understood, the long-term decline of groundwater storage presents a serious environmental challenge for the Confederated Tribes of the Umatilla Indian Reservation and communities in the URB. Close

• 30. [Article] Trajectory Analysis of Black Carbon in the Arctic Region

  Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates ...

  Citation × Citation Citation Abstract Copy Title: Trajectory Analysis of Black Carbon in the Arctic Region Author: Gottschalk, Kimberly Year: 2016 Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates making it a very efficient absorber of solar radiation. As BC is deposited on snow and ice, albedo is decreased - enhancing solar heating and increasing meltwater production. With rising air temperatures, melting rates of polar ice are increasing and are being enhanced by BC, leading to accelerated global sea level rise. This study aimed to document sources and deposition areas of BC in the Arctic. Utilizing HySplit, an air trajectory model, patterns of BC trajectories are assessed. Spatial patterns of deposition are estimated from known sources and source regions predicted from known deposition locations through the use of backward trajectory. Atmospheric circulation transports BC from temperate regions into the Arctic. The strength and location of the polar front in relation to the North Atlantic Oscillation is a dominant controlling factor. Preliminary results show reoccurring potential sources located in the Northeastern United States, Nova Scotia, Northern United Kingdom, and the Scandinavian Peninsula with large deposition events occurring within the first six months of the year. Title: Trajectory Analysis of Black Carbon in the Arctic Region Author: Gottschalk, Kimberly Year: 2016 Black carbon (BC) is a troubling particulate. Commonly known as soot, BC forms through the incomplete combustion of fossil fuels, biofuels, and biomass. It has a very low albedo compared to natural particulates making it a very efficient absorber of solar radiation. As BC is deposited on snow and ice, albedo is decreased - enhancing solar heating and increasing meltwater production. With rising air temperatures, melting rates of polar ice are increasing and are being enhanced by BC, leading to accelerated global sea level rise. This study aimed to document sources and deposition areas of BC in the Arctic. Utilizing HySplit, an air trajectory model, patterns of BC trajectories are assessed. Spatial patterns of deposition are estimated from known sources and source regions predicted from known deposition locations through the use of backward trajectory. Atmospheric circulation transports BC from temperate regions into the Arctic. The strength and location of the polar front in relation to the North Atlantic Oscillation is a dominant controlling factor. Preliminary results show reoccurring potential sources located in the Northeastern United States, Nova Scotia, Northern United Kingdom, and the Scandinavian Peninsula with large deposition events occurring within the first six months of the year. Close