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• 11. [Article] Repeat temperature measurements in boreholes from northwestern Utah link ground and air temperature changes at the decadal time scale

  Borehole temperature profiles provide a record of ground surface temperature (GST) change at the decadal to centennial time scale. GST histories reconstructed from boreholes are particularly useful in ...

  Citation × Citation Citation Abstract Copy Title: Repeat temperature measurements in boreholes from northwestern Utah link ground and air temperature changes at the decadal time scale Author: Chapman, David S., Harris, Robert N., Davis, Michael G. Borehole temperature profiles provide a record of ground surface temperature (GST) change at the decadal to centennial time scale. GST histories reconstructed from boreholes are particularly useful in climate reconstruction if changes in GST and surface air temperature (SAT) are effectively coupled at decadal and longer time periods and it can be shown that borehole temperatures respond faithfully to surface temperature changes. We test these assumptions using three boreholes in northwestern Utah that have been repeatedly logged for temperature over a time span of 29 years. We report 13 temperaturedepth logs at the Emigrant Pass Observatory borehole GC‐1, eight at borehole SI‐1 and five at borehole DM‐1, acquired between 1978 and 2007. Systematic subsurface temperature changes of up to 0.6°C are observed over this time span in the upper sections of the boreholes; below approximately 100 m any temperature transients are within observational noise. We difference the temperature logs to highlight subsurface transients and to remove any ambiguity resulting from steady state source of curvature. Synthetic temperature profiles computed from SAT data at nearby meteorological stations reproduce both the amplitude and pattern of the transient temperature observations, fitting the observations to within 0.03°C or better. This observational confirmation of the strong coupling between surface temperature change and borehole temperature transients lends further support to the use of borehole temperatures to complement SAT and multiproxy reconstructions of climate change. Title: Repeat temperature measurements in boreholes from northwestern Utah link ground and air temperature changes at the decadal time scale Author: Chapman, David S., Harris, Robert N., Davis, Michael G. Borehole temperature profiles provide a record of ground surface temperature (GST) change at the decadal to centennial time scale. GST histories reconstructed from boreholes are particularly useful in climate reconstruction if changes in GST and surface air temperature (SAT) are effectively coupled at decadal and longer time periods and it can be shown that borehole temperatures respond faithfully to surface temperature changes. We test these assumptions using three boreholes in northwestern Utah that have been repeatedly logged for temperature over a time span of 29 years. We report 13 temperaturedepth logs at the Emigrant Pass Observatory borehole GC‐1, eight at borehole SI‐1 and five at borehole DM‐1, acquired between 1978 and 2007. Systematic subsurface temperature changes of up to 0.6°C are observed over this time span in the upper sections of the boreholes; below approximately 100 m any temperature transients are within observational noise. We difference the temperature logs to highlight subsurface transients and to remove any ambiguity resulting from steady state source of curvature. Synthetic temperature profiles computed from SAT data at nearby meteorological stations reproduce both the amplitude and pattern of the transient temperature observations, fitting the observations to within 0.03°C or better. This observational confirmation of the strong coupling between surface temperature change and borehole temperature transients lends further support to the use of borehole temperatures to complement SAT and multiproxy reconstructions of climate change. Close

• 12. [Article] Summer stream temperatures and channel characteristics of a southwestern Oregon coastal stream

  The Elk River Basin drains 93 sq ml of steep forested terrain on the west side of the Klamath Mountains in Southwest Oregon. This river and its tributaries support a diverse and abundant population of ...

  Citation × Citation Citation Abstract Copy Title: Summer stream temperatures and channel characteristics of a southwestern Oregon coastal stream Author: McSwain, Michelle D. The Elk River Basin drains 93 sq ml of steep forested terrain on the west side of the Klamath Mountains in Southwest Oregon. This river and its tributaries support a diverse and abundant population of anadromous fish; a hatchery located at river mile 13 (km 21) supplements these native populations. Clear weather in combination with dry summers and low streamflow produce warm water temperatures. Historical data indicate that summer stream temperatures as high as 76°F (24.4°C) have occurred in the mainstem of the Elk River. This study was undertaken to evaluate summer stream temperatures and to what extent they were affected by natural factors and land use. In selected tributaries and along the mainstem of the Elk River, measurements were made on canopy cover, stream surface width, and thalweg depth during the summers of 1984 and 1985. Recording thermographs and maximum/minimum thermometers were used to determine the overall temperature pattern of the basin. In genera.l, maximum stream temperatures appear to be declining since 1970, following a period of increased landslide activity in the basin. The trend of decreasing maximum temperatures was not associated with changes in summer streamflow or summer precipitation patterns, suggesting that a recovery of streamside vegetation and/or change in channel morphology is proceeding within the basin. Tributaries with relatively large width / depth ratios (exceeding 14 or more), generally exhibited large diurnal fluctuations in temperature indicating solar heating was occurring. For drainages of similar size, large diurnal temperature fluctuations were associated with large surface area to volume ratios. Tributaries found to be especially low in maximum temperatures generally flow subsurface as a result of channel aggradation. In the 1984 and 1985 field seasons, maximum stream temperatures in the tributaries never exceeded the maximum temperature of 69°F (20.6°C) found in the mainstem. The upper reaches of the mainstem, which is wide and aggraded, was the portion of the basin found to have the highest maximum stream temperatures. Five pools were sampled to determine vertical profiles of temperature and dissolved oxygen. Temperatures and dissolved oxygen concentrations did not vary with depth. Title: Summer stream temperatures and channel characteristics of a southwestern Oregon coastal stream Author: McSwain, Michelle D. The Elk River Basin drains 93 sq ml of steep forested terrain on the west side of the Klamath Mountains in Southwest Oregon. This river and its tributaries support a diverse and abundant population of anadromous fish; a hatchery located at river mile 13 (km 21) supplements these native populations. Clear weather in combination with dry summers and low streamflow produce warm water temperatures. Historical data indicate that summer stream temperatures as high as 76°F (24.4°C) have occurred in the mainstem of the Elk River. This study was undertaken to evaluate summer stream temperatures and to what extent they were affected by natural factors and land use. In selected tributaries and along the mainstem of the Elk River, measurements were made on canopy cover, stream surface width, and thalweg depth during the summers of 1984 and 1985. Recording thermographs and maximum/minimum thermometers were used to determine the overall temperature pattern of the basin. In genera.l, maximum stream temperatures appear to be declining since 1970, following a period of increased landslide activity in the basin. The trend of decreasing maximum temperatures was not associated with changes in summer streamflow or summer precipitation patterns, suggesting that a recovery of streamside vegetation and/or change in channel morphology is proceeding within the basin. Tributaries with relatively large width / depth ratios (exceeding 14 or more), generally exhibited large diurnal fluctuations in temperature indicating solar heating was occurring. For drainages of similar size, large diurnal temperature fluctuations were associated with large surface area to volume ratios. Tributaries found to be especially low in maximum temperatures generally flow subsurface as a result of channel aggradation. In the 1984 and 1985 field seasons, maximum stream temperatures in the tributaries never exceeded the maximum temperature of 69°F (20.6°C) found in the mainstem. The upper reaches of the mainstem, which is wide and aggraded, was the portion of the basin found to have the highest maximum stream temperatures. Five pools were sampled to determine vertical profiles of temperature and dissolved oxygen. Temperatures and dissolved oxygen concentrations did not vary with depth. Close

• 13. [Article] Stream Temperature Modeling for Marys River Watershed

  High water temperatures in rivers have detrimental effects on riverine water quality and ecology. In this study, two river temperature models, within the agricultural watershed model Soil and Water Assessment ...

  Citation × Citation Citation Abstract Copy Title: Stream Temperature Modeling for Marys River Watershed Author: Mustafa, Mamoon High water temperatures in rivers have detrimental effects on riverine water quality and ecology. In this study, two river temperature models, within the agricultural watershed model Soil and Water Assessment Tool (SWAT), were investigated for their ability to simulate water temperatures accurately throughout the year. The original temperature model within SWAT uses a linear approach to estimate stream temperature based on air temperature and does not account for hydrological components for calculating stream temperature. Recently, a new stream temperature model for SWAT was developed that combines meteorological with hydrological components such as lateral flow, snowmelt, groundwater flow and surface runoff. The model also uses three elements for the stream temperature calculations – specifically, within a sub-basin (temperature and flow rate), upstream of sub-basin (temperature and incoming flow), and air-water temperature heat exchange transfer. The goal of this research was to improve the recently developed temperature model further by incorporating different types of heat exchange sources, in addition to air-water heat transfer. The edited model was tested for Marys River, a west tributary of the Willamette River in Oregon. The output from the edited model was then compared with observed stream temperatures, for different spatial locations within the watershed to assess the model efficiency. The results showed a good agreement for forested region compared to Ficklin’s default model with RMSE of both models matching. However, there were over predictions and more noise in predicting stream temperature for agricultural region within the watershed in which resulted in higher RMSE for edited model. Title: Stream Temperature Modeling for Marys River Watershed Author: Mustafa, Mamoon High water temperatures in rivers have detrimental effects on riverine water quality and ecology. In this study, two river temperature models, within the agricultural watershed model Soil and Water Assessment Tool (SWAT), were investigated for their ability to simulate water temperatures accurately throughout the year. The original temperature model within SWAT uses a linear approach to estimate stream temperature based on air temperature and does not account for hydrological components for calculating stream temperature. Recently, a new stream temperature model for SWAT was developed that combines meteorological with hydrological components such as lateral flow, snowmelt, groundwater flow and surface runoff. The model also uses three elements for the stream temperature calculations – specifically, within a sub-basin (temperature and flow rate), upstream of sub-basin (temperature and incoming flow), and air-water temperature heat exchange transfer. The goal of this research was to improve the recently developed temperature model further by incorporating different types of heat exchange sources, in addition to air-water heat transfer. The edited model was tested for Marys River, a west tributary of the Willamette River in Oregon. The output from the edited model was then compared with observed stream temperatures, for different spatial locations within the watershed to assess the model efficiency. The results showed a good agreement for forested region compared to Ficklin’s default model with RMSE of both models matching. However, there were over predictions and more noise in predicting stream temperature for agricultural region within the watershed in which resulted in higher RMSE for edited model. Close

• 14. [Article] Evaluation of stream temperature spatial variation using distributed temperature sensing

  Water temperature in rivers and streams is an important factor for aquatic ecosystem health. Measurement of stream temperature has traditionally been accomplished by point temperature measurements, continuous ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of stream temperature spatial variation using distributed temperature sensing Author: O'Donnell, Tara Water temperature in rivers and streams is an important factor for aquatic ecosystem health. Measurement of stream temperature has traditionally been accomplished by point temperature measurements, continuous point temperature loggers, and more recently, airborne remote sensing techniques such as Forward-Looking Infrared Radar (FLIR) or Thermal Infrared Radiometry. While each of these measurement techniques has certain advantages, none allows for the combined spatial and temporal information provided by Distributed Temperature Sensing (DTS). DTS employs fiber optic signals to measure temperature and is a relatively new temperature measurement technology for hydrologic sensing applications. Nine DTS stream temperature datasets were collected in the Middle Fork John Day River (MFJDR) as part of a basin-wide stream monitoring effort. The datasets encompassed five 1-3 kilometer long reaches, some monitored over three summers (2009-2011). In contrast to existing stream temperature measurement technologies, DTS can provide stream temperature data in both the spatial and temporal domains. Techniques and challenges of interpreting DTS stream temperature data were documented, and three applications of the technology to stream temperature monitoring were explored. Cold water patches, potentially used by fish as thermal refugia during stream temperature maximums, were located using DTS. No identified cold patch exceeded 2.31°C cooler than ambient stream temperature. Tributary inflows provided some of the most temperature-differentiated cold patches. These findings provide a reference for the degree of thermal heterogeneity in the MFJDR system and beg the question of whether fish respond to small (<3°C) spatial temperature variations. Theoretical predictions of stream mixing potential (Richardson number and cavity flow mixing predictions) suggested that increasing stream thermal heterogeneity would require channel modification to decrease stream flow velocity in select areas. The combined spatial and temporal coverage of a DTS stream temperature dataset on the Oxbow Conservation Area allowed diagnosis of a 2°C longitudinal stream temperature decrease observed in multiple Thermal Infrared Radiometry (TIR) and Forward-Looking Infrared Radiometry (FLIR) datasets collected on that reach. Advection velocity and channel depth, rather than groundwater or tributary inflows, were the main cause of the decrease, and the magnitude of the decrease peaked in the early afternoon, disappearing completely by evening. This finding suggests caution for interpretation of FLIR and TIR stream temperature datasets, which represent "snapshot" temperature measurements. For these datasets, knowledge of flow conditions (velocity and depth) may help avoid misinterpretation of temporally-transient temperature anomalies. Diurnal slope periodicity was observed in linear-like spatial trends in four DTS datasets, and an analysis was made to examine this subtle spatially and temporally varying phenomenon. The phase of the diurnal slope variation differed between river reaches, suggesting that propagation of larger-scale thermal waves might be one driving mechanism. Temporally-constant offsets between slope magnitudes within reaches suggested some intra-reach differences in heat fluxes. Title: Evaluation of stream temperature spatial variation using distributed temperature sensing Author: O'Donnell, Tara Water temperature in rivers and streams is an important factor for aquatic ecosystem health. Measurement of stream temperature has traditionally been accomplished by point temperature measurements, continuous point temperature loggers, and more recently, airborne remote sensing techniques such as Forward-Looking Infrared Radar (FLIR) or Thermal Infrared Radiometry. While each of these measurement techniques has certain advantages, none allows for the combined spatial and temporal information provided by Distributed Temperature Sensing (DTS). DTS employs fiber optic signals to measure temperature and is a relatively new temperature measurement technology for hydrologic sensing applications. Nine DTS stream temperature datasets were collected in the Middle Fork John Day River (MFJDR) as part of a basin-wide stream monitoring effort. The datasets encompassed five 1-3 kilometer long reaches, some monitored over three summers (2009-2011). In contrast to existing stream temperature measurement technologies, DTS can provide stream temperature data in both the spatial and temporal domains. Techniques and challenges of interpreting DTS stream temperature data were documented, and three applications of the technology to stream temperature monitoring were explored. Cold water patches, potentially used by fish as thermal refugia during stream temperature maximums, were located using DTS. No identified cold patch exceeded 2.31°C cooler than ambient stream temperature. Tributary inflows provided some of the most temperature-differentiated cold patches. These findings provide a reference for the degree of thermal heterogeneity in the MFJDR system and beg the question of whether fish respond to small (<3°C) spatial temperature variations. Theoretical predictions of stream mixing potential (Richardson number and cavity flow mixing predictions) suggested that increasing stream thermal heterogeneity would require channel modification to decrease stream flow velocity in select areas. The combined spatial and temporal coverage of a DTS stream temperature dataset on the Oxbow Conservation Area allowed diagnosis of a 2°C longitudinal stream temperature decrease observed in multiple Thermal Infrared Radiometry (TIR) and Forward-Looking Infrared Radiometry (FLIR) datasets collected on that reach. Advection velocity and channel depth, rather than groundwater or tributary inflows, were the main cause of the decrease, and the magnitude of the decrease peaked in the early afternoon, disappearing completely by evening. This finding suggests caution for interpretation of FLIR and TIR stream temperature datasets, which represent "snapshot" temperature measurements. For these datasets, knowledge of flow conditions (velocity and depth) may help avoid misinterpretation of temporally-transient temperature anomalies. Diurnal slope periodicity was observed in linear-like spatial trends in four DTS datasets, and an analysis was made to examine this subtle spatially and temporally varying phenomenon. The phase of the diurnal slope variation differed between river reaches, suggesting that propagation of larger-scale thermal waves might be one driving mechanism. Temporally-constant offsets between slope magnitudes within reaches suggested some intra-reach differences in heat fluxes. Close

• 15. [Article] Effects of modifying the environment on flowering, fruiting, and biochemical composition of the snap bean (Phaseolus vulgaris L.)

  The effects of modifying air temperature, soil temperature, and soil moisture levels on flowering, fruiting, and chemical composition of Tendercrop snap beans were studied in experiments in the field and ...

  Citation × Citation Citation Abstract Copy Title: Effects of modifying the environment on flowering, fruiting, and biochemical composition of the snap bean (Phaseolus vulgaris L.) Author: Singh, Jyotendra Narain The effects of modifying air temperature, soil temperature, and soil moisture levels on flowering, fruiting, and chemical composition of Tendercrop snap beans were studied in experiments in the field and in the greenhouse during 1961, 1962, and 1963. High maximum temperatures of 95-105° F. during bloom reduced the percent set and number and weight of pods of bean plants. Plants appeared to be most sensitive to temperatures at six to eight days after first bloom. Air temperatures in the field were increased 8-10° F. above controls by use of clear polyethylene plastic cages. The carbohydrate content of leaves and stems of plants subjected to high temperatures was decreased with a greater relative reduction of starch than of other sugars. Air temperature appeared also to affect the protein metabolism since cystine was not detected in plants subjected- to high temperature. Furthermore, threonine was detected in plants exposed to high temperatures, but not in control plants. Soil temperatures ranging from 55° to 90° F. had a pronounced effect on growth, flowering, and yield of snap beans, with best growth of plants and highest number of flowers and pods and weight of pods being obtained at soil temperatures of 75° to 80° F. Diurnal fluctuation of soil temperature had no advantage over comparable constant mean soil temperature for growth of plants. An exception was at fluctuating soil temperatures of 50-60° F- compared to constant temperature of 55° F. Soil temperature did not affect levels of total sugar and reducing sugar, but the starch content was decreased with an increase in soil temperature. Sucrose content of plants at fluctuating soil temperatures tended to be higher than in plants grown at comparable constant mean temperatures. Dry weight of shoots and roots and P and K content of plants increased with increased soil temperature. Magnesium content tended to decrease with an increase of soil temperature while Ca content of plants was variable. Snap bean plants which received the highest amount and frequency of irrigation from planting to harvest had the highest dry weight of shoots, number of flowers, percent set, and yield of pods when compared to plants subjected to moisture stress, either before or after bloom, or during both periods. On a dry weight basis, the carbohydrate content of leaves and stems of plants was highest when amount and frequency of irrigation was highest, but on the fresh weight basis, the carbohydrate content decreased with an increase in soil moisture. The stems and leaves of plants at the high moisture treatments contained highest levels of P and K while N and Mg levels of the same plants were lowest. A higher concentration of arginine was found in plants at high moisture levels than at low moisture levels. Tyrosine was detected in plants grown at the higher moisture, but not in plants subjected to moisture stress. Data suggest that soil moisture levels affected protein metabolism. Sucrose sprays had no significant effect on production of pods and carbohydrate content of bean plants. When soil temperature and moisture levels were varied, significant correlation co-efficients were obtained between weight of plants and number of pods, and between weight of plants and weight of pods. Data suggest that for highest yield, environmental factors should favor production of a large vigorous plant, with large photosynthetic capacity for bearing flowers and fruits. Bean plants appear to be especially sensitive to adverse temperature and moisture conditions during the period of anthesis and early pod development. Although adverse effects of high temperature and of moisture stress on pollination and fertilization were not studied, per se, in the present investigations, these adverse conditions caused a lower production of pods, lower carbohydrates levels, and appeared also to affect protein metabolism in snap beans. Further research is needed, especially to elucidate the adverse effects of high temperatures and moisture stress on biochemical processes and constituents of the snap bean and the significant relationship of these to growth, flowering, and fruiting. Title: Effects of modifying the environment on flowering, fruiting, and biochemical composition of the snap bean (Phaseolus vulgaris L.) Author: Singh, Jyotendra Narain The effects of modifying air temperature, soil temperature, and soil moisture levels on flowering, fruiting, and chemical composition of Tendercrop snap beans were studied in experiments in the field and in the greenhouse during 1961, 1962, and 1963. High maximum temperatures of 95-105° F. during bloom reduced the percent set and number and weight of pods of bean plants. Plants appeared to be most sensitive to temperatures at six to eight days after first bloom. Air temperatures in the field were increased 8-10° F. above controls by use of clear polyethylene plastic cages. The carbohydrate content of leaves and stems of plants subjected to high temperatures was decreased with a greater relative reduction of starch than of other sugars. Air temperature appeared also to affect the protein metabolism since cystine was not detected in plants subjected- to high temperature. Furthermore, threonine was detected in plants exposed to high temperatures, but not in control plants. Soil temperatures ranging from 55° to 90° F. had a pronounced effect on growth, flowering, and yield of snap beans, with best growth of plants and highest number of flowers and pods and weight of pods being obtained at soil temperatures of 75° to 80° F. Diurnal fluctuation of soil temperature had no advantage over comparable constant mean soil temperature for growth of plants. An exception was at fluctuating soil temperatures of 50-60° F- compared to constant temperature of 55° F. Soil temperature did not affect levels of total sugar and reducing sugar, but the starch content was decreased with an increase in soil temperature. Sucrose content of plants at fluctuating soil temperatures tended to be higher than in plants grown at comparable constant mean temperatures. Dry weight of shoots and roots and P and K content of plants increased with increased soil temperature. Magnesium content tended to decrease with an increase of soil temperature while Ca content of plants was variable. Snap bean plants which received the highest amount and frequency of irrigation from planting to harvest had the highest dry weight of shoots, number of flowers, percent set, and yield of pods when compared to plants subjected to moisture stress, either before or after bloom, or during both periods. On a dry weight basis, the carbohydrate content of leaves and stems of plants was highest when amount and frequency of irrigation was highest, but on the fresh weight basis, the carbohydrate content decreased with an increase in soil moisture. The stems and leaves of plants at the high moisture treatments contained highest levels of P and K while N and Mg levels of the same plants were lowest. A higher concentration of arginine was found in plants at high moisture levels than at low moisture levels. Tyrosine was detected in plants grown at the higher moisture, but not in plants subjected to moisture stress. Data suggest that soil moisture levels affected protein metabolism. Sucrose sprays had no significant effect on production of pods and carbohydrate content of bean plants. When soil temperature and moisture levels were varied, significant correlation co-efficients were obtained between weight of plants and number of pods, and between weight of plants and weight of pods. Data suggest that for highest yield, environmental factors should favor production of a large vigorous plant, with large photosynthetic capacity for bearing flowers and fruits. Bean plants appear to be especially sensitive to adverse temperature and moisture conditions during the period of anthesis and early pod development. Although adverse effects of high temperature and of moisture stress on pollination and fertilization were not studied, per se, in the present investigations, these adverse conditions caused a lower production of pods, lower carbohydrates levels, and appeared also to affect protein metabolism in snap beans. Further research is needed, especially to elucidate the adverse effects of high temperatures and moisture stress on biochemical processes and constituents of the snap bean and the significant relationship of these to growth, flowering, and fruiting. Close

• 16. [Article] The effects of thermal processing on the mechanical properties of AA2024, 2014 and 2618 aluminum alloys

  This study determined the independent effects of various homogenization cycles and precipitation treatments on the elevated temperature workability and the final ambient temperature mechanical properties ...

  Citation × Citation Citation Abstract Copy Title: The effects of thermal processing on the mechanical properties of AA2024, 2014 and 2618 aluminum alloys Author: Li, Xiao, 1963- This study determined the independent effects of various homogenization cycles and precipitation treatments on the elevated temperature workability and the final ambient temperature mechanical properties of AA2024 aluminum alloy and on the T3 tensile properties of 2014 aluminum alloy as well as T6 tensile properties of 2618 and 2618 (Curich) aluminum alloys. The elevated-temperature tensile and extrusion tests indicate that the workability of AA2024 alloy improves with elevated-temperature precipitation treatment as suggested by earlier investigations. The precipitation treatments do not appear to degrade the ambient-temperature T3 and T8 tensile properties. The time at the precipitation temperature appears to affect the T3 and T8 tensile properties in unextruded ingot, longer times especially providing both relatively high ambient-temperature strength and ductility of AA2024 alloy. The time at the standard homogenization temperature and the heat-up and cool-down rates do not dramatically affect the T3 tensile properties of unextruded ingot of AA2024 and 2014 alloys. However, long soak times at the homogenization temperature and more rapid cooling rates may improve the properties somewhat of AA2024 alloy and longer heat-up times and rapid cooling rates may slightly improve the properties of 2014 alloy. The higher standard solution temperature appears to increase both strength and ductility of 2014 alloy over lower temperatures. The homogenization temperature affects the T6 tensile properties of 2618 and 2618 (Cu-rich) alloys, a high homogenization temperature (compare to standard homogenization temperature) providing both high strength and ductility. Increased manganese and copper appears to increase the strength, but slightly decreases the ductility. The standard aging temperature and time produce higher strength but lower the ductility than lower temperatures at the same or shorter aging times in 2618 (Cu-rich) alloy. Title: The effects of thermal processing on the mechanical properties of AA2024, 2014 and 2618 aluminum alloys Author: Li, Xiao, 1963- This study determined the independent effects of various homogenization cycles and precipitation treatments on the elevated temperature workability and the final ambient temperature mechanical properties of AA2024 aluminum alloy and on the T3 tensile properties of 2014 aluminum alloy as well as T6 tensile properties of 2618 and 2618 (Curich) aluminum alloys. The elevated-temperature tensile and extrusion tests indicate that the workability of AA2024 alloy improves with elevated-temperature precipitation treatment as suggested by earlier investigations. The precipitation treatments do not appear to degrade the ambient-temperature T3 and T8 tensile properties. The time at the precipitation temperature appears to affect the T3 and T8 tensile properties in unextruded ingot, longer times especially providing both relatively high ambient-temperature strength and ductility of AA2024 alloy. The time at the standard homogenization temperature and the heat-up and cool-down rates do not dramatically affect the T3 tensile properties of unextruded ingot of AA2024 and 2014 alloys. However, long soak times at the homogenization temperature and more rapid cooling rates may improve the properties somewhat of AA2024 alloy and longer heat-up times and rapid cooling rates may slightly improve the properties of 2014 alloy. The higher standard solution temperature appears to increase both strength and ductility of 2014 alloy over lower temperatures. The homogenization temperature affects the T6 tensile properties of 2618 and 2618 (Cu-rich) alloys, a high homogenization temperature (compare to standard homogenization temperature) providing both high strength and ductility. Increased manganese and copper appears to increase the strength, but slightly decreases the ductility. The standard aging temperature and time produce higher strength but lower the ductility than lower temperatures at the same or shorter aging times in 2618 (Cu-rich) alloy. Close

• 17. [Article] Contributions of riparian vegetation and stream morphology to headwater stream temperature patterns in the Oregon Coast Range

  The role of riparian forests in maintaining temperatures of headwater streams is well established and is a foundation of forest practice rules designed to protect streamwater quality. However, detailed ...

  Citation × Citation Citation Abstract Copy Title: Contributions of riparian vegetation and stream morphology to headwater stream temperature patterns in the Oregon Coast Range Author: Smith, Danielle D. The role of riparian forests in maintaining temperatures of headwater streams is well established and is a foundation of forest practice rules designed to protect streamwater quality. However, detailed investigation is still needed quantifying specific characteristics of stream systems that affect streamwater temperature including riparian features, stream morphology, and subsurface interactions. The objectives of this research were to investigate summertime streamwater temperature patterns and identify characteristics within headwater streams and riparian zones that influence stream temperature. This study was designed to evaluate these relationships prior to logging in 38 perennial headwater catchments of the Oregon Coast Range. Stream reaches of greater than 1000 m were instrumented with temperature probes and selected stream and riparian characteristics were measured at 60-m intervals within each study reach in 2002 and 2003. A subset of the streams was examined in 2003 to determine the potential influence of streamwater residence time on temperature patterns. Findings suggest that canopy cover is the driving factor controlling summer stream temperature in these small headwater streams, but other stream and riparian characteristics should not be discarded. Longitudinal stream temperature patterns were quite variable for these forested streams and results suggest a high degree of complexity in small headwater streams. Maximum 7-day moving average temperatures ranged from 11.4°C to 16.8°C, with three streams above the standard 16°C threshold. Effects of stream and riparian characteristics on stream temperature were strongest when average of the weekly high temperature was assessed, suggesting this may be a more sensitive index of stream temperature than the commonly used maximum 7-day moving average. Results of tracer dilution tests were inconclusive in that temperature was not consistently correlated to residence time in streams. Title: Contributions of riparian vegetation and stream morphology to headwater stream temperature patterns in the Oregon Coast Range Author: Smith, Danielle D. The role of riparian forests in maintaining temperatures of headwater streams is well established and is a foundation of forest practice rules designed to protect streamwater quality. However, detailed investigation is still needed quantifying specific characteristics of stream systems that affect streamwater temperature including riparian features, stream morphology, and subsurface interactions. The objectives of this research were to investigate summertime streamwater temperature patterns and identify characteristics within headwater streams and riparian zones that influence stream temperature. This study was designed to evaluate these relationships prior to logging in 38 perennial headwater catchments of the Oregon Coast Range. Stream reaches of greater than 1000 m were instrumented with temperature probes and selected stream and riparian characteristics were measured at 60-m intervals within each study reach in 2002 and 2003. A subset of the streams was examined in 2003 to determine the potential influence of streamwater residence time on temperature patterns. Findings suggest that canopy cover is the driving factor controlling summer stream temperature in these small headwater streams, but other stream and riparian characteristics should not be discarded. Longitudinal stream temperature patterns were quite variable for these forested streams and results suggest a high degree of complexity in small headwater streams. Maximum 7-day moving average temperatures ranged from 11.4°C to 16.8°C, with three streams above the standard 16°C threshold. Effects of stream and riparian characteristics on stream temperature were strongest when average of the weekly high temperature was assessed, suggesting this may be a more sensitive index of stream temperature than the commonly used maximum 7-day moving average. Results of tracer dilution tests were inconclusive in that temperature was not consistently correlated to residence time in streams. Close

• 18. [Article] Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature

  This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data ...

  Citation × Citation Citation Abstract Copy Title: Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature Author: Harewood, Alessandra Greer This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data were gathered at four to seven locations along South Sister Creek in 2006, 2012, and 2013 and were used to explore whether restoration projects (in 2007 to 2011) affected stream temperature. Calculated seven-day maximum temperatures were cooler in post-treatment years (2012 and 2013) than the pre-treatment year (2006) at all four multi-year sites with the greatest differences near the mouth of the creek (4 to 5ºC cooler). While median stream temperature values were highest in 2013 for all four of the multi-year sites, the upper quartiles of measured hourly temperature for 2006 compared to 2012 and 2013 indicated more extreme high temperatures in 2006 than in subsequent years. Cross-correlation between stream and air temperature were used as an indicator of hyporheic flow. All peak CCF coefficients indicated a strong (.70) positive correlation in the early summer period between air and stream temperature, with lags ranging from 3 to 6 hours between peak air temperature and peak stream temperature. In the late summer period, most sites demonstrated lower correlations and longer lag times, patterns consistent with greater groundwater influence during low summer flows. There was no observable difference between pre- and post-treatment air-stream temperature cross correlation relationships. At a sub-reach scale, sites with more in-stream structural complexity -- including designed structures -- displayed greater spatial temperature variability than bedrock dominated reaches with simpler geomorphology. Title: Monitoring Restoration in South Sister Creek : The Effect of Stream Enhancement Structures on Water Temperature Author: Harewood, Alessandra Greer This pilot study of South Sister Creek (8 km length) examined stream-scale (i.e., longitudinal trends) and sub-reach scale (less than 100 m) water temperature. Hourly summer temperature time-series data were gathered at four to seven locations along South Sister Creek in 2006, 2012, and 2013 and were used to explore whether restoration projects (in 2007 to 2011) affected stream temperature. Calculated seven-day maximum temperatures were cooler in post-treatment years (2012 and 2013) than the pre-treatment year (2006) at all four multi-year sites with the greatest differences near the mouth of the creek (4 to 5ºC cooler). While median stream temperature values were highest in 2013 for all four of the multi-year sites, the upper quartiles of measured hourly temperature for 2006 compared to 2012 and 2013 indicated more extreme high temperatures in 2006 than in subsequent years. Cross-correlation between stream and air temperature were used as an indicator of hyporheic flow. All peak CCF coefficients indicated a strong (.70) positive correlation in the early summer period between air and stream temperature, with lags ranging from 3 to 6 hours between peak air temperature and peak stream temperature. In the late summer period, most sites demonstrated lower correlations and longer lag times, patterns consistent with greater groundwater influence during low summer flows. There was no observable difference between pre- and post-treatment air-stream temperature cross correlation relationships. At a sub-reach scale, sites with more in-stream structural complexity -- including designed structures -- displayed greater spatial temperature variability than bedrock dominated reaches with simpler geomorphology. Close

• 19. [Article] Heat source : stream, river and open channel temperature prediction

  Reach defined analysis concentrated on the water temperature change that occurred in a stream/river segment over the course of one full diurnal cycle. Digital thermistors, data loggers and computer model ...

  Citation × Citation Citation Abstract Copy Title: Heat source : stream, river and open channel temperature prediction Author: Boyd, Matthew S. Reach defined analysis concentrated on the water temperature change that occurred in a stream/river segment over the course of one full diurnal cycle. Digital thermistors, data loggers and computer model development were utilized in reach analysis to link parameters of the stream system to a specific temperature change. The methodology employed was relatively simple and fast, and many successive stream segments were analyzed simultaneously. Reach analysis of stream temperature change identified the existing components of the stream system that caused increased water temperature and predicted the effectiveness of managed improvements to the stream system. Stream and river temperature regulation has focused on system and basin wide management. Often, the source of increased water temperature originates in only a part of the stream system. Reach defined analysis identified the portions of the stream system in which most water temperature change occurred, offered an explanation for the temperature response and provided specific information about the alternate strategies that may ameliorate undesired water temperatures. The development of the computer model Heat Source included physically based mathematical descriptions of stream energy and hydrologic processes. An implicit finite difference numerical method was implemented for simultaneous solution. The methodology presented in Heat Source is portable and applicable to all streams, rivers and open channels. Title: Heat source : stream, river and open channel temperature prediction Author: Boyd, Matthew S. Reach defined analysis concentrated on the water temperature change that occurred in a stream/river segment over the course of one full diurnal cycle. Digital thermistors, data loggers and computer model development were utilized in reach analysis to link parameters of the stream system to a specific temperature change. The methodology employed was relatively simple and fast, and many successive stream segments were analyzed simultaneously. Reach analysis of stream temperature change identified the existing components of the stream system that caused increased water temperature and predicted the effectiveness of managed improvements to the stream system. Stream and river temperature regulation has focused on system and basin wide management. Often, the source of increased water temperature originates in only a part of the stream system. Reach defined analysis identified the portions of the stream system in which most water temperature change occurred, offered an explanation for the temperature response and provided specific information about the alternate strategies that may ameliorate undesired water temperatures. The development of the computer model Heat Source included physically based mathematical descriptions of stream energy and hydrologic processes. An implicit finite difference numerical method was implemented for simultaneous solution. The methodology presented in Heat Source is portable and applicable to all streams, rivers and open channels. Close

• 20. [Article] Small-Scale Sea Surface Temperature Structure

  Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer ...

  Citation × Citation Citation Abstract Copy Title: Small-Scale Sea Surface Temperature Structure Author: Paulson, Clayton A., Simpson, James J. Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer which viewed a disc on the surface 12 cm in diameter. The instrument responded to frequencies up to 3 Hz. Wave height was measured with a resistance gage located close to the field of view of the radiometer. Log-log plots of spectra of sea surface temperature exhibit a plateau between 0.05 and 0.5 Hz, followed by a rapid decrease in energy at frequencies >1 Hz. A coherence of 0.5 between waves and surface temperature occurs at the same frequency as the peak in the wave spectrum. Phase spectra show that warm temperatures associated with the thinning of the surface viscous layer occur systematically upwind of the crests of the dominant gravity waves and downwind of the crests of steeply sloping, shorter period gravity waves. The warm temperatures are hypothesized to be caused by enhanced wind stress upwind from the crests and by surface instability and surface convergence downwind from the crests. The magnitude of the mean temperature difference between the surface and the warmer, well-mixed water below is estimated from the surface temperature record. It is assumed that the warmest surface temperatures observed are associated with thinning of the viscous layer and are representative of the well-mixed water below. The dimensionless constant in a formula due to Saunders (1967), which relates the temperature difference to wind stress and heat flux, is found to be seven. Title: Small-Scale Sea Surface Temperature Structure Author: Paulson, Clayton A., Simpson, James J. Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer which viewed a disc on the surface 12 cm in diameter. The instrument responded to frequencies up to 3 Hz. Wave height was measured with a resistance gage located close to the field of view of the radiometer. Log-log plots of spectra of sea surface temperature exhibit a plateau between 0.05 and 0.5 Hz, followed by a rapid decrease in energy at frequencies >1 Hz. A coherence of 0.5 between waves and surface temperature occurs at the same frequency as the peak in the wave spectrum. Phase spectra show that warm temperatures associated with the thinning of the surface viscous layer occur systematically upwind of the crests of the dominant gravity waves and downwind of the crests of steeply sloping, shorter period gravity waves. The warm temperatures are hypothesized to be caused by enhanced wind stress upwind from the crests and by surface instability and surface convergence downwind from the crests. The magnitude of the mean temperature difference between the surface and the warmer, well-mixed water below is estimated from the surface temperature record. It is assumed that the warmest surface temperatures observed are associated with thinning of the viscous layer and are representative of the well-mixed water below. The dimensionless constant in a formula due to Saunders (1967), which relates the temperature difference to wind stress and heat flux, is found to be seven. Close