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Evapotranspiration over Spatially Extensive Plant Communities in Florida

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Frequently anticipated questions:

What does this data set describe?

Evapotranspiration over Spatially Extensive Plant Communities in Florida
Evapotranspiration (ET) and lake evaporation are quantified in Florida using the eddy covariance and Bowen ratio methods. Ecosystems selected for study include Lake Okeechobee, Pine Uplands, Wet Prairies, Marsh, Cypress Swamp, and Dwarf Cypress. These ecosystems are spatially extensive, and thus, the measurements described herein can be applied to other humid subtropical locations such as the Everglades. Spatial differences in annual ET are considerable due to incoming solar radiation variability and water availability. ET is generally greatest between March to October when solar radiation is relatively large, and least from November to February when solar radiation is small.
  1. How might this data set be cited?
    Shoemaker, W. Barclay, 2016, Evapotranspiration over Spatially Extensive Plant Communities in Florida.

    Online Links:

    For associated publication, see Scientific Investigations Report 2011-5212: http://pubs.usgs.gov/sir/2011/5212/
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -82.37
    East_Bounding_Coordinate: -79.82
    North_Bounding_Coordinate: 27.80
    South_Bounding_Coordinate: 25.00
    Big Cypress National Preserve, Blue Cypress Marsh, Lake Okeechobee
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2007
    Ending_Date: undefinedCurrentness_Reference: ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Maps and Data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    BCNP Evapotranspiration Data
    Evapotranspiration data and associated parameters for BCNP stations available in tab-delimited or CSV (comma-separated values) text format, which may then be imported into Excel, or most spreadsheet or database programs. (Source: U.S. Geological Survey)
    Time Frame
    Date range of data; not all stations have a full range of data (Source: U.S. Geological Survey)
    Range of values
    Data Variables
    The measured paramater available for download (Source: U.S. Geological Survey)
    Latent Heat (LH)Measured in Watts per meter squared
    Solar Radiation (SR)Measured in Watts per meter squared
    Net Radiation (NR)Measured in Watts per meter squared
    Sensible Heat Flux (SHF)Measured in Watts per meter squared
    Relative Humidity (RH)Percentage
    Air Temperature (AT)Degrees Celcius
    Water Distance Above (+) or Below (-) Land Surface (WD)Meters
    Evapotranspiration (ET)Millimeters per day
    Station names where data was collected (Source: U.S. Geological Survey)
    Cypress SwampCypress Swamp station located at 25° 45' 10" North, 81° 06' 01" West. Vegetation and substrate: Tall cypress strand. Date range available: 2007-04-25 to 2010-04-24. Data variables available: LH, SR, NR, SHF, RH, AT, Dbl, ET
    Dwarf CypressDward Cypress station located at 25° 45' 45" North, 80° 54' 27" West. Vegatation and substrate: Dwarf cypress and sawgrass (herbaceaous vegetation).. Date range available: 2007-04-18 to 2010-04-10. Data variables available: LH, SR, NR, SHF, RH, AT, Dbl, ET
    MarshMarsh station located at 26° 11' 57" North, 81° 15' 58" West. Vegetation and substrate: Deep-water marsh with tall (about 1-2 meters) sawgrass (herbaceous vegetation).Date range available: 2007-06-17 to 2010-04-20. Data variables available: LH, SR, NR, SHR, RH, AT, Dbl, ET
    Pine UplandPine Upland station located at 25° 59' 59" North, 80° 55' 29" West.. Vegetation and substrate: Pine upland and cypress domes. Date range available: 2007-04-23 to 2010-04-16. Data variables available: LH, SR, NR, SHR, RH, AT, Dbl, ET
    Wet PrairieWet Prairie station located at 25° 44' 41" North, 80° 56' 24" West. Date range available: 2007-10-10 to 2010-10-11. Data variables available: LH, SR, NR, SHF, RH, AT, Dbl, ET
    Lake OkeechobeeLZ40 station station located at 26° 54' 06" North, 80° 47' 21" West. Date range available: 2012-11-15 to 2014-12-31. Data variables available: LH, SR, NR, SHF, RH, AT, Dbl, ET
    Blue Cypress MarshBlue Cypress Marsh station located at 26° 54' 06" North, 80° 47' 21" West. Date range available: 2009-12-11 to 2014-10-20. Data variables available: LH, SR, NR, SHF, RH, AT, Dbl, ET

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • W. Barclay Shoemaker
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    W. Barclay Shoemaker
    USGS Caribbean-Florida Water Science Center
    3321 College Avenue
    Davie, FL 33314

    954-377-5956 (voice)

Why was the data set created?

To quantify ET and lake evaporation in southern Florida at daily, monthly and annual time scales.

How was the data set created?

  1. What methods were used to collect the data?
    Method 0 of 3
    Type: Field
    Eddy covariance instrumentation comprises sonic anemometers and krypton hygrometers that measure latent- and sensible-heat fluxes, respectively. Hygrometer voltage is proportional to attenuated radiation emitted from a hygrometer source tube to a hygrometer detector tube. Voltage fluctuations are related to fluctuations in vapor density by Beer-Lambert Law (Weeks and others, 1987). Sonic anemometers detect changes in the transit time of emitted sound waves to infer fluctuations in wind speed in three orthogonal directions, sonic air temperature, and sensible heat.
    Method 0 of 3
    Type: Field
    Meteorological instrumentation was installed to measure solar radiation, net radiation, soil-heat flux, vapor-density fluctuations, rainfall, soil-moisture content, air and soil temperatures, relative humidity, distance of water above and below land surface, and mean wind speed and direction and the maximum wind gusts measured during a 30-minute averaging period. Four component net radiometers were installed in April 2008 at the forested ET sites (Pine Upland, Cypress Swamp, and Dwarf Cypress) as part of a separate project with goals of quantifying albedos for satellite-based ET estimates. However, Kipp and Zonen net radiometers were used during quality-assurance quality-control procedures that force energy-budget closure and within Priestly-Taylor ET models for gap filling. Kipp and Zonen net radiometers were available at all five ET sites. Thus, differences in net radiation among the sites cannot be explained by use of different net radiometer brands and manufacturing procedures. Sap-flow data also were collected at the forested ET sites in an effort to estimate transpiration.
    Method 0 of 3
    Type: Field
    Sites visits were made every month to download data, perform a sensor inspection and other complete equipment maintenance. All instrumentation was visually inspected, leveled, cleaned, or replaced as necessary. Krypton hygrometer source and detector tube windows were cleaned when necessary with a cotton swab and water to remove dust obstructions and restore the signal strength. Net radiometers were releveled, if necessary. Desiccants were replaced to prevent moisture accumulation within instrumentation enclosures. Depth-to-water measurements were taken with a steel or electric water tape from the top of well casings to the water surface. Depth-to-water measurements were used to develop drift corrections for the pressure transducer readings. Digital photographs of the vegetation community were generally taken during monthly site inspections.
  2. From what previous works were the data drawn?
  3. How were the data generated, processed, and modified?
    Date: 2010 (process 1 of 1)
    The eddy covariance energy-budget method (Dyer, 1961; Tanner and Greene, 1989; Bidlake and others, 1996) was used to measure evapotranspiration (ET) for this study.
  4. What similar or related data should the user be aware of?
    Bidlake, W.R., Woodham, W.M., and Lopez, M.A., 2006, Evapotranspiration from areas of native vegetation in west-central Florida: U.S. Geological Survey Water-Supply Paper 2430.

    Other_Citation_Details: 35 pp.
    Dryer, A.J., 1961, Measurements of evaporation and heat transfer in the lower atmosphere by an automatic eddy covariance technique: Quarterly Journal of the Royal Meterological Society 87.

    Other_Citation_Details: p. 401-412
    Tanner, B.D., and Greene, J.P., 1989, Measurement of sensible heat and water vapor fluxes using eddy covariance methods.

    Final report prepared for U.S. Army Dugway Proving Grounds, Dugway, Utah, 17 p.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    See publication for additional information on Attribute Accuracy
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    See publication for additional information on Completeness
  5. How consistent are the relationships among the observations, including topology?
    See publication for additional information on Logical Consistency

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
Cite primary authors and database when using or publishing these data
  1. Who distributes the data set? (Distributor 1 of 1)
    Heather S. Henkel
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, FL 33701

    727-502-8028 (voice)
    727-502-8182 (FAX)
  2. What's the catalog number I need to order this data set? BCNP Evapotranspiration Data database
  3. What legal disclaimers am I supposed to read?
    The data have no explicit or implied guarantees
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Data for the stations with selectable variables in format ASCII (version see Format Specification) comma-separated values (.csv) or tab-delimited text files
      Network links: https://sofia.usgs.gov/exchange/evapotrans/.
    • Cost to order the data: none

Who wrote the metadata?

Last modified: 15-Oct-2016
Metadata author:
Heather S. Henkel
U.S. Geological Survey
600 4th Street South
St. Petersburg, FL 33701

727-502-8028 (voice)
727-502-8182 (FAX)
Metadata standard:
FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata (FGDC-STD-001.1-1999)

Generated by mp version 2.9.34 on Sat Oct 15 06:53:09 2016

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Last updated: 23 December, 2016 @ 01:49 PM (KP)