US-Tw2: Twitchell Corn

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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-Tw2 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-Tw2 data are combined with data from sites that require the AmeriFlux Legacy Policy.

AmeriFlux BASE: https://doi.org/10.17190/AMF/1246148
Citation: Cove Sturtevant, Joseph Verfaillie, Dennis Baldocchi (2019), AmeriFlux BASE US-Tw2 Twitchell Corn, Ver. 2-5, AmeriFlux AMP, (Dataset). https://doi.org/10.17190/AMF/1246148
AmeriFlux FLUXNET: https://doi.org/10.17190/AMF/1881593
Citation: Cove Sturtevant, Joseph Verfaillie, Dennis Baldocchi (2024), AmeriFlux FLUXNET-1F US-Tw2 Twitchell Corn, Ver. 4-6, AmeriFlux AMP, (Dataset). https://doi.org/10.17190/AMF/1881593

Find global FLUXNET datasets, like FLUXNET2015 and FLUXNET-CH4, and their citation information at fluxnet.org.

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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US-Tw2: Twitchell Corn

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US-Tw2: Twitchell Corn

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US-Tw2: Twitchell Corn

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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.

Includes all pixels that have acceptable quality

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

Read more on how to cite these MODIS products. Data come from NASA’s MODIS instruments installed on satellites Terra and Aqua, which scan the entire Earth’s surface every one to two days.

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 site

GeoNEX Data Products

Beta: This AmeriFlux GeoNEX Products feature is in beta. If you spot any issues, please help us out by emailing geonex-feedback@lbl.gov with a description and/or screenshot of the issue. Thanks in advance!

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 .

Click a square in the grid at left to display its data below.

Coordinates for selected GeoNEX Pixel

Graph controls:

Zoom: click-drag
Pan: shift-click-drag
Restore zoom level: double-click
Use the slider below the time series to zoom in and out.

All download requests will be logged.

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.

GeoNEX Surface Downward Solar Radiation (DSR):

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.

GeoNEX Land Surface Temperature (LST):

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-Tw2: Twitchell Corn

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Search Publications for this Site Publications Found: 6

AmeriFlux Publications

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Year	Publication
2021	Chu, H., Luo, X., Ouyang, Z., Chan, W. S., Dengel, S., Biraud, S. C., Torn, M. S., Metzger, S., Kumar, J., Arain, M. A., Arkebauer, T. J., Baldocchi, D., Bernacchi, C., Billesbach, D., Black, T. A., Blanken, P. D., Bohrer, G., Bracho, R., Brown, S., Brunsell, N. A., Chen, J., Chen, X., Clark, K., Desai, A. R., Duman, T., Durden, D., Fares, S., Forbrich, I., Gamon, J. A., Gough, C. M., Griffis, T., Helbig, M., Hollinger, D., Humphreys, E., Ikawa, H., Iwata, H., Ju, Y., Knowles, J. F., Knox, S. H., Kobayashi, H., Kolb, T., Law, B., Lee, X., Litvak, M., Liu, H., Munger, J. W., Noormets, A., Novick, K., Oberbauer, S. F., Oechel, W., Oikawa, P., Papuga, S. A., Pendall, E., Prajapati, P., Prueger, J., Quinton, W. L., Richardson, A. D., Russell, E. S., Scott, R. L., Starr, G., Staebler, R., Stoy, P. C., Stuart-Haëntjens, E., Sonnentag, O., Sullivan, R. C., Suyker, A., Ueyama, M., Vargas, R., Wood, J. D., Zona, D. (2021) Representativeness Of Eddy-Covariance Flux Footprints For Areas Surrounding Ameriflux Sites, Agricultural And Forest Meteorology, 301-302, 108350. https://doi.org/10.1016/j.agrformet.2021.108350
2019	Sullivan, R. C., Kotamarthi, V. R., Feng, Y. (2019) Recovering Evapotranspiration Trends From Biased CMIP5 Simulations And Sensitivity To Changing Climate Over North America, Journal Of Hydrometeorology, 20(8), 1619-1633. https://doi.org/10.1175/JHM-D-18-0259.1
2019	Sullivan, R. C., Cook, D. R., Ghate, V. P., Kotamarthi, V. R., Feng, Y. (2019) Improved Spatiotemporal Representativeness And Bias Reduction Of Satellite-Based Evapotranspiration Retrievals Via Use Of In Situ Meteorology And Constrained Canopy Surface Resistance, Journal Of Geophysical Research: Biogeosciences, 124(2), 342-352. https://doi.org/10.1029/2018JG004744
2019	Hemes, K. S., Chamberlain, S. D., Eichelmann, E., Anthony, T., Valach, A., Kasak, K., Szutu, D., Verfaillie, J., Silver, W. L., Baldocchi, D. D. (2019) Assessing The Carbon And Climate Benefit Of Restoring Degraded Agricultural Peat Soils To Managed Wetlands, Agricultural And Forest Meteorology, 268, 202-214. https://doi.org/10.1016/j.agrformet.2019.01.017
2018	Baldocchi, D., Penuelas, J. (2018) The Physics And Ecology Of Mining Carbon Dioxide From The Atmosphere By Ecosystems, Global Change Biology, . https://doi.org/10.1111/gcb.14559
2014	Knox, S. H.,, Sturtevant, C., Matthes, J.H., Koteen, L., Verfaillie,J., Baldocchi. D. (2014) Agricultural peatland restoration: effects of land-use change on greenhouse gas (CO2 and CH4) fluxes in the Sacramento-San Joaquin Delta, Global Change Biology, 21, 750-765. https://doi.org/10.1111/gcb.12745

US-Tw2: Twitchell Corn

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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^*

View Site General Info for this site (Overview tab)^*

Use Online Editor to update Site General Info or DOI Authorship

Update information about submitted data (Variable Information tool)

More BADM resources

^* 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-Tw2: Twitchell Corn

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Wind Roses

Click an image below to enlarge it, or use the navigation panel.

Image scale: 799m x 799m

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 (%)

Show Satellite Image

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

Tower_team:
PI:	Dennis Baldocchi baldocchi@berkeley.edu - University of California, Berkeley
AncContact:	Joe Verfaillie jverfail@berkeley.edu - University of California, Berkeley
Lat, Long:	38.0969, -121.6365
Elevation(m):	-5
Network Affiliations:	AmeriFlux
Vegetation IGBP:	CRO (Croplands: Lands covered with temporary crops followed by harvest and a bare soil period (e.g., single and multiple cropping systems). Note that perennial woody crops will be classified as the appropriate forest or shrub land cover type.)
Climate Koeppen:	Csa (Mediterranean: mild with dry, hot summer)
Mean Annual Temp (°C):	15.5
Mean Annual Precip. (mm):	421
Flux Species Measured:	CO2, H2O
Years Data Collected:	2012 - 2013
Years Data Available:	AmeriFlux BASE 2012 - 2013 Data Citation AmeriFlux FLUXNET 2012 - 2013 Data Citation
Data Use Policy:	AmeriFlux CC-BY-4.0 Policy¹
Description:	The Twitchell Corn site is a corn field on peat soil. The tower was installed on May 17, 2012 and was equipped to analyze energy, H2O and CO2 fluxes. The ... The Twitchell Corn site is a corn field on peat soil. The tower was installed on May 17, 2012 and was equipped to analyze energy, H2O and CO2 fluxes. The field was planted in early May 2012 and harvested in early November 2012. The field was fallow during the non-growing season. The variety of corn used was ES-7477 hybrid corn commercialized by Eureka seeds. Beginning 2013-05-09 this site was converted to wetland. The tower was moved 540m ESE to avoid earth moving in the construction. The site is near US-Tw1, US-Tw3 and US-Twt sites. See More Show Less
URL:	http://nature.berkeley.edu/biometlab/sites.php?tab=US-Tw2
Research Topics:	The research approach of the University of California, Berkeley Biometeorology Laboratory involves the coordinated use of experimental measurements and ... The research approach of the University of California, Berkeley Biometeorology Laboratory involves the coordinated use of experimental measurements and theoretical models to understand the physical, biological, and chemical processes that control trace gas fluxes between the biosphere and atmosphere and to quantify their temporal and spatial variations. The research objectives of the Mayberry Wetland, Twitchell Wetland, Sherman Island, Twitchell Island, Twitchell Alfalfa, and Twitchell Corn sites are as follows: 1) Describe differences in the fluxes of CO2, CH4, H2O, and energy between different land uses; 2) Understand the mechanisms controlling these fluxes; 3) Use ecosystem modeling to understand controls on these mechanisms under different environmental scenarios. These six sites were selected to capture a wide range of inundated conditions within the Sacramento-San Joaquin River Delta. The research focuses on the eddy covariance technique to measure CH4, CO2, H2O, and energy fluxes and works to combine measurements of both net fluxes and partitioned fluxes in order to achieve a mechanistic understanding of the ecological controls on current and future carbon flux in the Delta. See More Show Less
Acknowledgment:	Biometeorology Lab, University of California, Berkeley, PI: Dennis Baldocchi

US-Tw2: Twitchell Corn

US-Tw2: Twitchell Corn

DOI(s) for citing US-Tw2 data

Publication(s) for citing site characterization

Acknowledgments

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US-Tw2: Twitchell Corn

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US-Tw2: Twitchell Corn

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US-Tw2: Twitchell Corn

US-Tw2: Twitchell Corn

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US-Tw2: Twitchell Corn

Wind Roses

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