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US-NR4: Niwot Ridge Alpine (T-Van East)

Tower_team:
PI: John Knowles John.knowles@montana.edu - Montana State University
AncContact: Sarah Elmendorf Sarah.Elmendorf@Colorado.edu - University of Colorado Boulder
FluxContact: Peter Blanken blanken@Colorado.edu - University of Colorado Boulder
Lat, Long: 40.0520, -105.5859
Elevation(m): 3502
Network Affiliations: AmeriFlux
Vegetation IGBP: GRA (Grasslands: Lands with herbaceous types of cover. Tree and shrub cover is less than 10%. Permanent wetlands lands with a permanent mixture of water and herbaceous or woody vegetation. The vegetation can be present in either salt, brackish, or fresh water.)
Climate Koeppen: ET (Tundra)
Mean Annual Temp (°C): -2.2
Mean Annual Precip. (mm): 884
Flux Species Measured: CO2, H2O
Years Data Collected: 2007 - Present
Years Data Available:

AmeriFlux BASE 2007 - 2023   Data Citation
Data Use Policy:AmeriFlux CC-BY-4.0 Policy1
Description:
Snow-scoured alpine tundra; Fellfield vegetation; 3-m tower located 50 m E of US-NR3, 387 m SW of US-xNW, and 28 km west of Boulder, CO, USA. Reliable ...
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URL: https://nwt.lternet.edu/
Research Topics: Sublimation; Carbon cycle; Water balance; Ecosystem function in complex mountain terrain
Acknowledgment: Funding was provided by National Science Foundation DEB awards 0423662, 1027341, 1637686, and 2224439 to the Niwot Ridge LTER.
Site Tasks
  1. This site’s data can also be used under the more restrictive AmeriFlux Legacy Policy.
    The AmeriFlux Legacy Policy must be followed if this site’s data are combined with data from sites that require the AmeriFlux Legacy Policy.
Site Photo More Site Images
Image Credit: John Knowles, 07/27/2008
Copyright preference: As long as credit is given
Site Publication More Site Publications
Knowles, J. F., Blanken, P. D., Williams, M. W., Chowanski, K. M. 2012. Energy And Surface Moisture Seasonally Limit Evaporation And Sublimation From Snow-Free Alpine Tundra, Agricultural And Forest Meteorology, 157, 106-115.

US-NR4: Niwot Ridge Alpine (T-Van East)

Use the information below for citation of this site. See the Data Policy page for more details.

DOI(s) for citing US-NR4 data

Data Use Policy: AmeriFlux CC-BY-4.0 License

This site’s data can also be used under the more restrictive AmeriFlux Legacy Policy.
The AmeriFlux Legacy Policy must be followed if US-NR4 data are combined with data from sites that require the AmeriFlux Legacy Policy.

  • AmeriFlux BASE: https://doi.org/10.17190/AMF/1804492
    Citation: John Knowles (2024), AmeriFlux BASE US-NR4 Niwot Ridge Alpine (T-Van East), Ver. 5-5, AmeriFlux AMP, (Dataset). https://doi.org/10.17190/AMF/1804492

To cite BADM when downloaded on their own, use the publications below for citing site characterization. When using BADM that are downloaded with AmeriFlux BASE and AmeriFlux FLUXNET products, use the DOI citation for the associated data product.

Publication(s) for citing site characterization

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Acknowledgments

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Resources

US-NR4: Niwot Ridge Alpine (T-Van East)

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US-NR4: Niwot Ridge Alpine (T-Van East)

Year Publication
2023 Jay, K. R., Wieder, W. R., Swenson, S. C., Knowles, J. F., Elmendorf, S. C., Holland‐Moritz, H., Suding, K. N. (2023) Topographic Heterogeneity And Aspect Moderate Exposure To Climate Change Across An Alpine Tundra Hillslope, Journal Of Geophysical Research: Biogeosciences, 128(11), . https://doi.org/10.1029/2023JG007664
2015 Knowles, J. F., Harpold, A. A., Cowie, R., Zeliff, M., Barnard, H. R., Burns, S. P., Blanken, P. D., Morse, J. F., Williams, M. W. (2015) The Relative Contributions Of Alpine And Subalpine Ecosystems To The Water Balance Of A Mountainous, Headwater Catchment, Hydrological Processes, 29(22), 4794-4808. https://doi.org/10.1002/hyp.10526
2015 Knowles, J. F., Blanken, P. D., Williams, M. W. (2015) Soil Respiration Variability Across A Soil Moisture And Vegetation Community Gradient Within A Snow-Scoured Alpine Meadow, Biogeochemistry, 125(2), 185-202. https://doi.org/10.1007/s10533-015-0122-3
2016 Knowles, J. F., Blanken, P. D., Williams, M. W. (2016) Wet Meadow Ecosystems Contribute The Majority Of Overwinter Soil Respiration From Snow-Scoured Alpine Tundra, Journal Of Geophysical Research: Biogeosciences, 121(4), 1118-1130. https://doi.org/10.1002/2015JG003081
2017 Wieder, W. R., Knowles, J. F., Blanken, P. D., Swenson, S. C., Suding, K. N. (2017) Ecosystem Function In Complex Mountain Terrain: Combining Models And Long-Term Observations To Advance Process-Based Understanding, Journal Of Geophysical Research: Biogeosciences, 122(4), 825-845. https://doi.org/10.1002/2016JG003704
2018 Sexstone, G. A., Clow, D. W., Fassnacht, S. R., Liston, G. E., Hiemstra, C. A., Knowles, J. F., Penn, C. A. (2018) Snow Sublimation In Mountain Environments And Its Sensitivity To Forest Disturbance And Climate Warming, Water Resources Research, 54(2), 1191-1211. https://doi.org/10.1002/2017WR021172
2019 Knowles, J. F., Blanken, P. D., Lawrence, C. R., Williams, M. W. (2019) Evidence For Non-Steady-State Carbon Emissions From Snow-Scoured Alpine Tundra, Nature Communications, 10(1), . https://doi.org/10.1038/s41467-019-09149-2
2012 Knowles, J. F., Blanken, P. D., Williams, M. W., Chowanski, K. M. (2012) Energy And Surface Moisture Seasonally Limit Evaporation And Sublimation From Snow-Free Alpine Tundra, Agricultural And Forest Meteorology, 157, 106-115. https://doi.org/10.1016/j.agrformet.2012.01.017
2009 Blanken, P. D., Williams, M. W., Burns, S. P., Monson, R. K., Knowles, J. F., Chowanski, K., Ackerman, T. (2009) A Comparison Of Water And Carbon Dioxide Exchange At A Windy Alpine Tundra And Subalpine Forest Site Near Niwot Ridge, Colorado, Biogeochemistry, 95(1), 61-76. https://doi.org/10.1007/s10533-009-9325-9
2015 Knowles, J. F., Burns, S. P., Blanken, P. D., Monson, R. K. (2015) Fluxes Of Energy, Water, And Carbon Dioxide From Mountain Ecosystems At Niwot Ridge, Colorado, Plant Ecology & Diversity, 8(5-6), 663-676. https://doi.org/10.1080/17550874.2014.904950

US-NR4: Niwot Ridge Alpine (T-Van East)

BADM for This Site

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* Online updates are shown on the Overview tab real time. However, downloaded BADM files will not reflect those updates until they have been reviewed for QA/QC.

US-NR4: Niwot Ridge Alpine (T-Van East)

Wind Roses

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  • Image scale: 777m x 777m
  • Data Collected:
    • Wind roses use variables ‘WS’ and ‘WD’.
    Download Data Download Wind Rose as Image File (PNG)

    Wind Speed (m/s)

  • Graph Type
  • Wind Speed Scale
  • Wind Direction Scale (%)
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  • Show Wind Rose
    • Annual Average
    About Ameriflux Wind Roses
    Wind Rose Explanation
    A wind rose gives a succinct view of how wind speed and direction are typically distributed at a particular location. Presented in a circular format, a wind rose shows the frequency and intensity of winds blowing from particular directions. The length of each “spoke” around the circle indicates the amount of time (frequency) that the wind blows from a particular direction. Colors along the spokes indicate categories of wind speed (intensity). Each concentric circle represents a different frequency, emanating from zero at the center to increasing frequencies at the outer circles
    Utility
    This information can be useful to gain insight into regions surrounding a flux tower that contribute to the measured fluxes, and how those regions change in dependence of the time of day and season. The wind roses presented here are for four periods of the year, and in 16 cardinal directions. Graphics are available for all sites in the AmeriFlux network based on reported wind measurements at each site.
    Data from each site can be downloaded by clicking the ‘download’ button.
    Hover the cursor over a wind rose to obtain directions, speeds and intensities.
    Note that wind roses are not equivalent to flux footprints. Specifically, the term flux footprint describes an upwind area “seen” by the instruments measuring vertical turbulent fluxes, such that heat, water, gas and momentum transport generated in this area is registered by the instruments. Wind roses, on the other hand, identify only the direction and speed of wind.
    Where do these data come from?
    The wind roses are based on observed hourly data from the sites registered with the AmeriFlux Network.
    Parameters for AmeriFlux Wind Roses
    To use wind roses for a single AmeriFlux site, the following parameters may be most useful:
    • Wind Speed Scale: Per Site
    • Wind Direction Scale (%): Per Site
    To compare wind roses from more than one single AmeriFlux site, the following parameters may be most useful:
    • Wind Speed Scale: Non-Linear
    • Wind Direction Scale (%): AmeriFlux
    Mar - Jun; 6am - 6pm
    Mar - Jun; 6pm - 6am
    Jun - Sep; 6am - 6pm
    Jun - Sep; 6pm - 6am
    Sep - Dec; 6am - 6pm
    Sep - Dec; 6pm - 6am
    Dec - Mar; 6am - 6pm
    Dec - Mar; 6pm - 6am