ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (10)
  • Wiley  (10)
  • American Chemical Society
  • American Institute of Physics (AIP)
  • National Academy of Sciences
  • Nature Publishing Group
  • Springer Nature
  • 2010-2014  (10)
  • Hydrological Processes  (4)
  • 1951
  • 1
    facet.materialart.
    Unknown
    Stream nitrate uptake and transient storage over a gradient of geomorphic complexity, north-central Colorado, USA (2011)
    Wiley
    Details
    Publication Date: 2011-11-05
    Description: The understanding of nutrient uptake in streams is impeded by limited understanding of how geomorphic setting and flow regime interact with biogeochemical processing. This study investigates these interactions as they relate to transient storage and nitrate uptake in small agricultural and urban streams. Sites were selected across a gradient of channel conditions and management modifications and included three 180-m long geomorphically distinct reaches on each of two streams in north-central Colorado. The agricultural stream has been subject to historically variable cattle-grazing practices and the urban stream exhibits various levels of stabilization and planform alteration. Reach-scale geomorphic complexity was characterized using highly detailed surveys of channel morphology, substrate, hydraulics, and habitat units. Breakthrough-curve modeling of conservative bromide (Br - ) and non-conservative nitrate (NO 3 - ) tracer injections characterized transient storage and nitrate uptake along each reach. Longitudinal roughness and flow depth were positively associated with transient storage, which was related to nitrate uptake, thus underscoring the importance of geomorphic influences on stream biogeochemical processes. Additionally, changes in geomorphic characteristics due to temporal discharge variation led to complex responses in nitrate uptake. Copyright © 2011 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Influences of sudden changes in discharge and physical stream characteristics on transient storage and nitrate uptake in an urban stream (2014)
    Wiley
    Details
    Publication Date: 2014-06-25
    Description: Changes in the physical structure of urban streams can occur abruptly due to flashy high flow events and subsequently alter stream processes, including transient storage and nitrate uptake. We examined temporal variability in transient storage and nitrate uptake by exploring the effects of altered physical characteristics resulting from a single high flow event in three reaches of Spring Creek, an urban stream in Fort Collins, Colorado, USA. Study reaches of varying geomorphic and hydraulic characteristics were chosen to represent distinct geomorphic settings in terms of substrate size, sinuosity, bed slope, and degree of rehabilitation and structural controls. We performed detailed physical characterizations and multiple nutrient injections of Br − and NO 3 − to estimate transient storage and nitrate uptake in each reach. A comparison of pre- and post-flood data indicate that transient storage and nitrate uptake are highly context-specific and mediated by interactions between geomorphic setting and flood discharge. In the two reaches that showed significant post-flood increases in transient storage (250% to 350% increases in F med 200 ), the pool-riffle reach exhibited a significant increase in uptake velocity, while the channelized reach did not. In contrast, transient storage decreased post-flood in the third reach containing hydraulic structures. These complex responses likely reflect reach-specific differences in hyporheic vs. in-channel storage. This study shows that repeat injections are necessary to describe nutrient dynamics because transient storage and nitrate uptake can be highly variable over time (showing changes on the order of 100%) due to variation in discharge and geomorphically influential flow events. This article is protected by copyright. All rights reserved.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Satellite perspectives on the spatial patterns of new snowfall in the Southern Appalachian Mountains (2014)
    Wiley
    Details
    Publication Date: 2014-03-18
    Description: ABSTRACT The Southern Appalachian Mountains (SAM) are a heavily forested mid-latitude mountain region which provide an ideal location for assessing the suitability of satellite-derived snow maps and explicitly linking atmospheric circulation to the spatial patterns of new snowfall. Although a variety of synoptic-scale circulation regimes contribute to mean annual snowfall, which ranges from roughly 25 cm in the lowest valleys to over 250 cm at the highest elevations, atmospheric circulation processes have largely been absent from efforts seeking to quantify the spatial patterns of new snowfall. In this paper, we examine the suitability of fractional snow cover (FSC) maps from the Moderate Resolution Imaging Spectroradiometer (MODIS) and determine the spatial extent of snowfall according to synoptic-scale circulation. FSC maps are analyzed after 122 snow events from 2006-12 to provide a suitability analysis of MODIS products for use in the SAM. For each event, we calculate FSC distribution, total snow covered area, and compare with available in-situ observations. Results indicate that the SAM presents unique meteorological, physical, and spectral characteristics that are ideal for evaluating the suitability of MODIS for measuring snow cover. Out of 122 observed snow events, 63 are considered suitable for analysis with the FSC maps. The highest FSC values are observed after Gulf/Atlantic Lows and southeastward tracking clipper systems. We conclude that MODIS data can be successfully used to link broader atmospheric circulation processes of snowfall with the spatial patterns of snow cover. This article is protected by copyright. All rights reserved.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    The high hydraulic conductivity of three wooded tropical peat swamps in northeast Peru: measurements and implications for hydrological function (2013)
    Wiley
    Details
    Publication Date: 2013-05-09
    Description: The form and functioning of peatlands depend strongly on their hydrological status, but there are few data available on the hydraulic properties of tropical peatlands. In particular, the saturated hydraulic conductivity ( K ) has not previously been measured in Neotropical peatlands. Piezometer slug tests were used to measure K at two depths (50 and 90 cm) in three contrasting forested peatlands in the Peruvian Amazon; Quistococha, San Jorge, and Buena Vista. Measured K at 50 cm depth varies between 0.00032 and 0.11 cm s -1 , and at 90 cm it varies between 0.00027 and 0.057 cm s -1 . Measurements of K taken from different areas of Quistococha showed that spatial heterogeneity accounts for c. 20 % of the within-site variance, and that depth is a good predictor of K . However, K did not vary significantly with depth at Buena Vista and San Jorge. Statistical analysis showed that c. 18 % of the variance in the K -data can be explained by between-site differences. Simulations using a simple hydrological model suggest the relatively high K values could lead to lowering of the water table by 〉 10 cm within c. 48 m of the peatland edge for domed peatlands, if subjected to a drought lasting 30 days. However, under current climatic conditions, even with high K , peatlands would be unable to shed the large amount of water entering the system via rainfall through subsurface flow alone. We conclude that most of the water leaves these peatlands via overland flow and/or evapotranspiration. This article is protected by copyright. All rights reserved.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    Structural evolution during ice-sphere sintering (2010)
    Wiley
    Details
    Publication Date: 2010-06-10
    Description: Two-dimensional ice-sphere arrays were produced in a cold room and studied as a geometrically simplified model of dry snow aggregates. The structural evolution of the ice-sphere arrays under either a quasi-isothermal condition or a temperature gradient was examined temporally. Two observational techniques were combined for the structural characterization. Optical microscopy was used to perform periodic observations, whereas scanning electron microscopy was used to both acquire high-resolution images and confirm the hexagonal crystal structure. Different thermal conditions led to the development of different morphologies of necks between two ice spheres by affecting the water vapour transfer in the pore spaces and the sublimation-condensation of water molecules. The microstructure of necks could also play a significant role in the structure development at later times by inducing or enhancing the local temperature gradient. This feature was discussed on the basis of steady-state heat transfer modelling of a two-sphere structure. Copyright © 2010 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Observations of the morphology and sublimation-induced changes in uncoated snow using scanning electron microscopy (2010)
    Wiley
    Details
    Publication Date: 2010-01-01
    Description: The morphology of a fresh-snow specimen and the sublimation-induced structural changes in an individual snow crystal were examined using a high-vacuum scanning electron microscope (SEM) equipped with a cryo system. The snow specimen was collected during a snowfall in Hanover, NH, USA, and was initially maintained at liquid nitrogen temperature in order to prevent any structural changes. Without coating, snow crystals can sublimate in the SEM chamber at a rate that is mainly determined by the temperature of the specimen. After the initial morphology was examined at -180 oC, sublimation was initiated by slowly increasing the stage temperature, and changes in morphology were recorded by taking images of an individual snow crystal intermittently and recording the temperatures and times. Severe morphological destructions due to sublimation occurred at around -150 oC. This approach allowed us to closely observe both the initial morphology and the structural changes in snow crystals as they underwent sublimation, a significant process during snow metamorphism. These observations also serve as a reference for temperature selection in the study of uncoated snow with a similar morphology using a high-vacuum SEM. Copyright © 2010 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Stream nitrate uptake and transient storage over a gradient of geomorphic complexity, north-central Colorado, USA (2012)
    Wiley
    Details
    Publication Date: 2012-01-18
    Description: The understanding of nutrient uptake in streams is impeded by a limited understanding of how geomorphic setting and flow regime interact with biogeochemical processing. This study investigated these interactions as they relate to transient storage and nitrate uptake in small agricultural and urban streams. Sites were selected across a gradient of channel conditions and management modifications and included three 180-m long geomorphically distinct reaches on each of two streams in north-central Colorado. The agricultural stream has been subject to historically variable cattle-grazing practices, and the urban stream exhibits various levels of stabilisation and planform alteration. Reach-scale geomorphic complexity was characterised using highly detailed surveys of channel morphology, substrate, hydraulics and habitat units. Breakthrough-curve modelling of conservative bromide (Br - ) and nonconservative nitrate (NO 3 - ) tracer injections characterised transient storage and nitrate uptake along each reach. Longitudinal roughness and flow depth were positively associated with transient storage, which was related to nitrate uptake, thus underscoring the importance of geomorphic influences on stream biogeochemical processes. In addition, changes in geomorphic characteristics due to temporal discharge variation led to complex responses in nitrate uptake. © 2011 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    The high hydraulic conductivity of three wooded tropical peat swamps in northeast Peru: measurements and implications for hydrological function (2013)
    Wiley
    Details
    Publication Date: 2013-06-08
    Description: The form and functioning of peatlands depend strongly on their hydrological status, but there are few data available on the hydraulic properties of tropical peatlands. In particular, the saturated hydraulic conductivity (K) has not previously been measured in neotropical peatlands. Piezometer slug tests were used to measure K at two depths (50 and 90cm) in three contrasting forested peatlands in the Peruvian Amazon: Quistococha, San Jorge and Buena Vista. Measured K at 50cm depth varies between 0.00032 and 0.11cms-1, and at 90cm, it varies between 0.00027 and 0.057cms-1. Measurements of K taken from different areas of Quistococha showed that spatial heterogeneity accounts for ~20% of the within-site variance and that depth is a good predictor of K. However, K did not vary significantly with depth at Buena Vista and San Jorge. Statistical analysis showed that ~18% of the variance in the K data can be explained by between-site differences. Simulations using a simple hydrological model suggest that the relatively high K values could lead to lowering of the water table by 〉10cm within ~48m of the peatland edge for domed peatlands, if subjected to a drought lasting 30days. However, under current climatic conditions, even with high K, peatlands would be unable to shed the large amount of water entering the system via rainfall through subsurface flow alone. We conclude that most of the water leaves these peatlands via overland flow and/or evapotranspiration. © 2013 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Influences of sudden changes in discharge and physical stream characteristics on transient storage and nitrate uptake in an urban stream (2014)
    Wiley
    Details
    Publication Date: 2014-08-01
    Description: Changes in the physical structure of urban streams can occur abruptly due to flashy high-flow events and subsequently alter stream processes, including transient storage and nitrate uptake. We examined temporal variability in transient storage and nitrate uptake by exploring the effects of altered physical characteristics resulting from a single high-flow event in three reaches of Spring Creek, an urban stream in Fort Collins, Colorado, USA. Study reaches of varying geomorphic and hydraulic characteristics were chosen to represent distinct geomorphic settings in terms of substrate size, sinuosity, bed slope, and degree of rehabilitation and structural controls. We performed detailed physical characterizations and multiple nutrient injections of Br- and NO3- to estimate transient storage and nitrate uptake in each reach. A comparison of pre-flood and post-flood data indicates that transient storage and nitrate uptake are highly context specific and mediated by interactions between geomorphic setting and flood discharge. In the two reaches that showed significant post-flood increases in transient storage (250% to 350% increases in Fmed200), the pool-riffle reach exhibited a significant increase in uptake velocity, while the channelized reach did not. In contrast, transient storage decreased post-flood in the third reach containing hydraulic structures. These complex responses likely reflect reach-specific differences in hyporheic versus in-channel storage. This study shows that repeat injections are necessary to describe nutrient dynamics because transient storage and nitrate uptake can be highly variable over time (showing changes on the order of 100%) due to variation in discharge and geomorphically influential flow events. © 2014 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Satellite perspectives on the spatial patterns of new snowfall in the Southern Appalachian Mountains (2014)
    Wiley
    Details
    Publication Date: 2014-04-03
    Description: The Southern Appalachian Mountains (SAM) are a heavily forested mid-latitude mountain region that provide an ideal location for assessing the suitability of satellite-derived snow maps and explicitly linking atmospheric circulation to the spatial patterns of new snowfall. Although a variety of synoptic-scale circulation regimes contribute to mean annual snowfall, which ranges from roughly 25cm in the lowest valleys to over 250cm at the highest elevations, atmospheric circulation processes have largely been absent from efforts seeking to quantify the spatial patterns of new snowfall. In this paper, we examine the suitability of fractional snow cover (FSC) maps from the Moderate Resolution Imaging Spectroradiometer (MODIS) and determine the spatial extent of snowfall according to synoptic-scale circulation. FSC maps are analysed after 122 snow events from 2006 to 2012 to provide a suitability analysis of MODIS products for use in the SAM. For each event, we calculate FSC distribution and total snow-covered area and compare it with available in situ observations. Results indicate that the SAM presents unique meteorological, physical, and spectral characteristics that are ideal for evaluating the suitability of MODIS for measuring snow cover. Out of 122 observed snow events, 63 are considered suitable for analysis with the FSC maps. The highest FSC values are observed after Gulf/Atlantic lows and south-eastward tracking clipper systems. We conclude that MODIS data can be successfully used to link broader atmospheric circulation processes of snowfall with the spatial patterns of snow cover. © 2014 John Wiley & Sons, Ltd.
    Print ISSN: 0885-6087
    Electronic ISSN: 1099-1085
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...