US-NR4: Niwot Ridge Alpine (T-Van East)
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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 - 2024 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 ... 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 nearby daily precipitation data (NWT D1) can be found at: https://doi.org/10.6073/pasta/63b912a406254df036e89c84a1b59230. See MoreShow Less |
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. |
- This site’s data can also be used under the more restrictive AmeriFlux Legacy Policy.
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Copyright preference: As long as credit is given
US-NR4: Niwot Ridge Alpine (T-Van East)
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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 (2025), AmeriFlux BASE US-NR4 Niwot Ridge Alpine (T-Van East), Ver. 6-5, 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
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US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM

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US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM
AmeriFlux Images | Add Image |

Mid-winter snow distribution results from the interaction of wind and micro-topography
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Location: Colorado, United States
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Snow accumulation after a wet spring storm
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Location: Colorado, United States
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Spring snow
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Location: Colorado, United States
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Above the inversion
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Location: Colorado, United States
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Looking southeast
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Location: Colorado, United States
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Looking WSW toward Kiowa peak
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Location: Colorado, United States
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Tower closeup
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Location: Colorado, United States
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Typical snow-scoured winter conditions, US-NR3 in the background
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Location: Colorado, United States
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Looking east along Niwot Ridge
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Location: Colorado, United States
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US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM
MODIS NDVI
The time series shows the 16-day Normalized Difference Vegetation Index (NDVI) average from the MOD13Q1 data product.
Use the slider below the time series to zoom in and out.
To view / download these data and other MOD13Q1 products for this site, visit MODIS/Terra Vegetation Indices.
For other related products, visit MODIS/VIIRS Fixed Sites Subsets Tool.
Citation:
ORNL DAAC. 2018. Terrestrial Ecology Subsetting & Visualization Services (TESViS) Fixed Sites Subsets. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1567
MODIS NDVI subsetted data is not yet available for this site.
For a complete list of AmeriFlux sites, visit ORNL DAAC's MODIS/VIIRS Fixed Sites Subsets Tool.
PhenoCam Images and Derived Time Series Data
PhenoCams are high-resolution digital cameras that take repeated images of studied ecosystems and provide quantitative information about the canopy phenology. The PhenoCam Network coordinates the camera installation and data reporting/analyses across sites in the Americas, providing automated, near-surface remote sensing of canopy phenology across a range of ecosystems and climate zones. Use of PhenoCam images / data should follow the PhenoCam Data Use Policy .
No PhenoCam data for this siteGeoNEX Data Products
GeoNEX led by NASA Earth eXchange (NEX) is a collaborative effort for generating Earth monitoring products from the new generation of geostationary satellite sensors. GeoNEX has produced a suite of geostationary data products including surface reflectance, land surface temperature, surface solar radiation, and many others.
The GeoNEX Common Grid locates GeoNEX data in the geographic (latitude/longitude) projection. Pixels (grid cells) are created at regular 0.005°, 0.01°, and 0.02° resolutions.
GeoNEX pixels below cover the area 0.06° x 0.06° around and including site US-NR4, 40.052, -105.5859.
Click a square in the grid at left to display its data below.
Coordinates for selected GeoNEX Pixel
Graph controls:
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NDVI: Normalized Difference Vegetation Index
Resolution: 0.01° x 0.01° & 10 minutes
Coordinates for pixel:
NIRv Near-Infrared Reflectance of vegetation
Resolution: 0.01° x 0.01° & 10 minutes
Coordinates for pixel:
DSR: Surface downward shortwave radiation
Resolution: 0.01° x 0.01° & Hourly
Coordinates for pixel:
LST: Land Surface Temperature
Resolution: 0.02° x 0.02° & Hourly
Coordinates for pixel:
Citation
This material can be used without obtaining permission from NASA. NASA should be acknowledged as the source of this material.
Subset Data Citation:
- Hashimoto, H., Wang, W., Park, T., Khajehei, S., Ichii, K., Michaelis, A.R., Guzman, A., Nemani, R.R., Torn, M., Yi, K., Brosnan, I.G. (in preparation). Subsets of geostationary satellite data over international observing network sites for studying the diurnal dynamics of energy, carbon, and water cycles.
Relevant Science Publication Citation:
GeoNEX Surface Reflectance for Vegetation Indices (NDVI & NIRv)- Wang, W., Wang, Y., Lyapustin, A., Hashimoto, H., Park, T., Michaelis, A., & Nemani, R. (2022). A novel atmospheric correction algorithm to exploit the diurnal variability in hypertemporal geostationary observations. Remote Sensing, 14(4), 964.
- Li, R., Wang, D., Wang, W., & Nemani, R. (2023). A GeoNEX-based high-spatiotemporal-resolution product of land surface downward shortwave radiation and photosynthetically active radiation. Earth System Science Data, 15(3), 1419-1436.
- Jia, A., Liang, S., & Wang, D. (2022). Generating a 2-km, all-sky, hourly land surface temperature product from Advanced Baseline Imager data. Remote Sensing of Environment, 278, 113105.
US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM
AmeriFlux Publications | Add Publication |
US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM
BADM for This Site
Access the Biological, Ancillary, Disturbance and Metadata (BADM) information and data for this site.
BADM contain information for many uses, such as characterizing a site’s vegetation and soil, describing disturbance history, and defining instrumentation for flux processing. They complement the flux/met data.
- Download BADM for this site*
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US-NR4: Niwot Ridge Alpine (T-Van East)
- Overview
- Windroses
- Data Citation
- Data Use Log
- Image Gallery
- Remote Sensing Data
- MODIS
- PhenoCam
- GeoNEX
- Publications
- BADM
Wind Roses
Wind Speed (m/s)
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