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Evapotranspiration Measuring and Modeling in the Everglades

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Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Sandra Kinnaman
Publication_Date: 2004
Title: Evapotranspiration Measuring and Modeling in the Everglades
Geospatial_Data_Presentation_Form: text files
Online_Linkage: <https://sofia.usgs.gov/projects/index.php?project_url=evapotrans>
Description:
Abstract:
The overall objective is to develop a process-oriented appraisal of evapotranspiration within the Everglades drainage unit, excluding agricultural and brackish environments. Specific objectives include: 1) Field measurement of evapotranspiration at a variety of sites encompassing a regionally representative range of environmental factors.; 2) Integration of evapotranspiration estimates into a process-oriented model; 3) Verification and refinement of model using Et measurements at additional sites.
Purpose:
Everglades restoration efforts will rely heavily upon development of hydrologic flow models that will be used to help guide restoration and management decisions. Any hydrologic model requires an assessment of the water budget, including the amount of water removed from the system by evapotranspiration (Et). Et is a major part of the water budget in the Everglades, being similar in magnitude to rainfall. The Everglades Et project provides the necessary Et data, and methods of estimating Et throughout the Everglades system, that are required by all flow models.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 199410
Ending_Date: 200309
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -80.83
East_Bounding_Coordinate: -80.26
North_Bounding_Coordinate: 26.76
South_Bounding_Coordinate: 25.29
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: hydrology
Theme_Keyword: water budget
Theme_Keyword: ET
Theme_Keyword: evapotranspiration
Theme_Keyword: model
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: environment
Theme_Keyword: inlandWaters
Theme_Keyword: climatologyMeteorologyAtmosphere
Theme_Keyword: 004
Theme_Keyword: 007
Theme_Keyword: 012
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, DC, National Institute of Standards and Technology
Place_Keyword: United States
Place_Keyword: US
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, DC, NIST
Place_Keyword: Florida
Place_Keyword: FL
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1990, Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas, FIPS 6-3, Washington, DC, National Institute of Standards and Technology
Place_Keyword: Miami-Dade County
Place_Keyword: Monroe County
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: Central Everglades
Place_Keyword: Water Conservation Area 1
Place_Keyword: Water Conservation Area 2
Place_Keyword: Water Conservation Area 3
Place_Keyword: WCA1
Place_Keyword: WCA2
Place_Keyword: WCA3
Place:
Place_Keyword_Thesaurus: USGS Geographic Names Information System
Place_Keyword: Shark River Slough
Place_Keyword: Taylor Slough
Place_Keyword: Everglades National Park
Place_Keyword: Loxahatchee National Wildlife Refuge
Access_Constraints: none
Use_Constraints: none
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Sandra Kinnaman
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 12703 Research Parkway
City: Orlando
State_or_Province: FL
Postal_Code: 32826
Country: USA
Contact_Voice_Telephone: 407 803-5541
Contact_Electronic_Mail_Address: kinnaman@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: <https://sofia.usgs.gov/projects/evapotrans/regeval1b.gif>
Browse_Graphic_File_Description:
The Everglades and locations of evapotranspiration (Et) stations
Browse_Graphic_File_Type: GIF
Data_Set_Credit:
Dave Stannard, USGS NRP, Denver, has provided project operation and data analysis during the project. Eddie Simonds has also helped on the project.
Native_Data_Set_Environment: ASCII text files
Cross_Reference:
Citation_Information:
Originator: Edward R. German
Publication_Date: 2000
Title:
Regional Evaluation of Evapotranspiration in the Everglades (2000)
Geospatial_Data_Presentation_Form: report
Series_Information:
Series_Name: Water Resources investigations Report
Issue_Identification: 00-4217
Publication_Information:
Publication_Place: Tallahassee, FL
Publisher: U.S. Geological Survey
Other_Citation_Details: accessed as of 10/27/2010
Online_Linkage: <http://fl.water.usgs.gov/Abstracts/wri00_4217_german.html>
Cross_Reference:
Citation_Information:
Originator: German, E. R.
Publication_Date: 1999
Title:
Regional Evaluation of Evapotranspiration in the Everglades (1999)
Geospatial_Data_Presentation_Form: report
Series_Information:
Series_Name: Third International Symposium on Ecohydraulics
Issue_Identification: Proceedings
Publication_Information:
Publication_Place: Salt Lake City, UT
Publisher: International Association for Hydraulic Research
Other_Citation_Details: accessed as of 5/24/2010
Online_Linkage: <https://sofia.usgs.gov/publications/papers/evalET/>
Cross_Reference:
Citation_Information:
Originator: German, E. R.
Publication_Date: 2002
Title:
Evapotranspiration rates from two different sawgrass communities in South Florida during drought conditions
Geospatial_Data_Presentation_Form: report
Series_Information:
Series_Name: Second Federal Interagency Hydrologic Modeling Conference
Issue_Identification: Proceedings
Publication_Information:
Publication_Place: Las Vegas, NV
Publisher:
Subcommittee on Hydrology, of the Advisory Committee on Water Information
Cross_Reference:
Citation_Information:
Originator: Ohmura, A.
Publication_Date: 1982
Title:
Objective criteria for rejecting data for Bowen ratio flux calculations
Geospatial_Data_Presentation_Form: report
Series_Information:
Series_Name: Journal of Applied Meteorology
Issue_Identification: v. 21, n. 4, p. 595-598
Publication_Information:
Publication_Place: Boston, MA
Publisher: American Meteorological Society
Other_Citation_Details: accessed as of 10/27/2010
Online_Linkage:
<http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281982%29021%3C0595%3AOCFRDF%3E2.0.CO%3B2>

Data_Quality_Information:
Logical_Consistency_Report: not applicable
Completeness_Report:
Not all sites have data for all 15 parameters collected. wtm - the average water temperature at a fixed position 1-2 feet above land surface was not collected at most stations.
Lineage:
Process_Step:
Process_Description:
A network of Et-measurement sites was established in the Everglades in 1996, representing the various types of hydrologic and vegetative environments. Eight sites were operated in 1996 and nine sites were operated in 1997. Data from these sites were used to characterize Et and other meteorological conditions in the Everglades, and to develop models of Et as a function of solar radiation and water level. A report describing these findings was published in 2000. Data collection continued at selected sites during 1998-2000 to provide data for other studies involved with understanding water levels and flows in the Everglades.

In 2000, new sites were established in Shark Valley Slough, to test transferability of models developed using 1996-97 data, and to refine the understanding of factors related to Et. As of January 2003 there were five continuous Et sites in the Everglades National Park.

The original sites were selected to provide a network representative of the non-forested portion of the Everglades ecosystem in terms of plant communities, duration of water inundation (hydroperiod), and geographic coverage. Other factors in site selections were security and logistics. Sites in areas open to hunting and air boating were located in relatively remote locations and not on major air boat trails. Each site was located at the center of a circle of relatively uniform vegetative cover with a radius of at least 100 times the height of the upper air temperature/humidity sensor.

Stations were instrumented to provide data for: determination of total energy available for Et (latent heat flux) and convection (sensible heat flux); determination of the Bowen ratio (the ratio sensible heat flux/ latent heat flux), so that the amount of the total available energy that was utilized for Et could be determined; and characterization of meteorological conditions and Et-model development using ancillary data.

The array and arrangement of data sensors at the sites were dependent on whether the site was in open water or in dense, emergent vegetation. The major difference between open-water sites and vegetated sites is the method of determining the air-temperature and humidity differential with height, which is necessary for computation of the Bowen ratio. At the two open-water sites (sites 2 and 3), the air temperature and humidity differentials were measured from the water surface to a point 3-4 feet above the water surface. At the seven vegetated sites (sites 1, 4-9) the differentials were measured between two points in air, 3-5 feet apart.

At each site, sensor measurements were made automatically every 30-seconds and these measurements were averaged and stored onsite at 15- or 30- minute intervals. These data were then transmitted daily by cellular telephone to computer storage in the office. Data were reviewed on a daily basis to detect equipment breakdown and sensor malfunction. Site visits were made at approximately monthly intervals for routine scheduled maintenance and cleaning, or more frequently when malfunctions occurred.

Data were collected from January 1996 through December 1997 for sites 1, 2, 3, and 5. Data were collected from January 1996 through December 1999 for site 4, from December 1996 through December 1998 for site 6, and from January 1996 through December 2000 for sites 7 and 8. Site 9 was installed in January 1997 to increase representation of drier parts of the Everglades; site 9 furnished data from January 1997 through December 1997. Only data that passed screening tests for accuracy were used to develop the models of Et. The screening tests were based on range limits, visual inspection of plotted net radiation, temperature and humidity readings to eliminate periods when sensors were obviously malfunctioning, and on criteria given by Ohmura (1982). These criteria specified that flux calculations are inappropriate if the calculated latent heat flux is in the opposite direction from the observed vapor-pressure vertical difference. Such a situation would indicate an error in determination of either the energy budget or the vapor-pressure or temperature vertical differences. Ohmura also recommended that Bowen-ratio calculations be rejected if temperature or vapor-pressure vertical differences are at or less than sensor resolution limits. Resolution limits for this study are 0.013 degree Celsius for vertical temperature differences and 0.003 kilopascal (kPa) for vapor-pressure differences. These screening criteria eliminated about one-half of the available data from model development, mostly because of sensor failure and resolution limits. Most of the data rejected because of resolution limits or flux directions were for night-time hours, when energy inputs, air-temperature vertical differences, and vapor-pressure vertical differences are all relatively low.

Sites were visited at 4-6 week intervals for inspection and maintenance. Maintenance generally included the following items:

Ventilator fans - Clean and replace, if not operating Net radiometer domes - Clean and replace, if damaged. Replace radiometer if water damaged Radiation shields (air temperature and humidity) - Clean Air temperature and humidity sensors - Clean, replace sensors, if necessary. Water-level sensor - Raise float and check for proper response. Rain gage - Check for obstructions, clear if necessary; test calibration periodically. Water temperature sensors - Check for proper position and reading. Net radiometers and pyranometer - Check for level, adjust if necessary. Sensor exchange mechanism - Check for smooth operation, replace as necessary. Field verification of air temperature, relative humidity, wind speed, and wind direction using handheld meters.

The net radiometer domes required the most frequent maintenance. These domes, made of soft transparent polyethylene, shield the sensors from moisture, wind, or debris that could affect sensor performance. Problems encountered included crushing by hail, pecking by birds, and gradual deterioration of the polyethylene. Domes were changed at 3-month intervals, or sooner if damage occurred. If the domes were cracked, punctured, or there was evidence of water penetration into the sensor, the entire net radiometer was replaced.

Air temperature and humidity sensors failed frequently during the first year of operation, due to corrosion of electrical contacts. A change in sensor design resulted in much-improved service life of these sensors during the second year of operation. The sensor exchange mechanisms were subject to occasional failure, generally due to mechanical wear or water penetration into the control circuitry.

Net radiation is measured directly by the net radiometers, but the measured value is affected by wind speed and must be corrected. The wind correction factor was calculated from wind measured at the sites using procedures described by C. Fritchen of REBS, Inc. in a personal communication. Soil heat flux was measured at all vegetated sites, but was not measured at the open-water sites because these sites were always covered by water, generally to a depth of more than 1 ft. At the vegetated sites the soil heat flux was determined from the sum of heat flux measured by a heat-flux plate buried 5 centimeters (cm) below the land surface and the change in heat stored in the soil profile above the plate. Water heat storage was calculated at all sites whenever water was standing on the water surface. At open-water sites with little or no emergent vegetation, the air-temperature and vapor-pressure differentials necessary for the Bowen-ratio determination are determined from measurements of water temperature at the water surface and air temperature and vapor pressure at a point 3 to 4 ft above the water surface. The water-surface temperature is measured by using a float -mounted thermocouple, and is assumed to represent the air temperature at the water-air interface. The vapor pressure at that point is assumed to be equivalent to 100 percent relative humidity. Because the differences between water surface and air are much greater than differences in the air over similar distances, the effect of air and vapor pressure sensor bias is negligible. Therefore, the sensor exchange mechanism is not required and only one air temperature /vapor pressure sensor is needed at such sites.

See WRIR 00-4217 (<http://fl.water.usgs.gov/PDF_files/wri00_4217_german.pdf>) for more detail and the formulas used in the calculations.

Any use of trade, product, or firm names is for descriptive purposes only and does not constitute endorsement by the U.S. Government

Process_Date: 2004
Process_Step:
Process_Description:
Et station operation ended Sept. 30, 2003. All sites were removed by November 2003.

Data analysis and modeling

Data processing will be completed for all sites, to provide actual Et data, together with related meteorological data.

Process_Date: 2004
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Sandra Kinnaman
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 12703 Research Parkway
City: Orlando
State_or_Province: FL
Postal_Code: 32826
Country: USA
Contact_Voice_Telephone: 407 803-5541
Contact_Electronic_Mail_Address: kinnaman@usgs.gov

Spatial_Data_Organization_Information:
Indirect_Spatial_Reference: Everglades
Direct_Spatial_Reference_Method: Point
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: Point
Point_and_Vector_Object_Count: 13

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 1
Longitude_Resolution: 1
Geographic_Coordinate_Units: Degrees, minutes, and decimal seconds
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257

Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
At each site, measurements necessary for evapotranspiration (ET) calculation and modeling were automatically made and stored on-site at 15- or 30-minute intervals. Data collected included air temperature and humidity at two heights, wind speed and direction, incoming solar radiation, net solar radiation, water level and temperature, soil moisture content, soil temperature, soil heat flux, and rainfall.
Entity_and_Attribute_Detail_Citation:
Water-Resources Investigations Report 2000-4217 at <http://fl.water.usgs.gov/PDF_files/wri00_4217_german.pdf>

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather S. Henkel
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 600 Fourth St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727 803-8747 ext 3028
Contact_Facsimile_Telephone: 727 803-2030
Contact_Electronic_Mail_Address: hhenkel@usgs.gov
Resource_Description: Evapotranspiration Data
Distribution_Liability: The data have no implied or explicit guarantees
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ASCII
Format_Information_Content:
File contains data for sites 1-9, Old Ingraham Highway pan site, and the L1, X1.5, and X2 sites.
File_Decompression_Technique: File is zipped and needs to be "unzipped" before use
Transfer_Size: 25.5
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <https://sofia.usgs.gov/exchange/german/germanet.html>
Access_Instructions: Data may be downloaded from the SOFIA website
Fees: None

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather S. Henkel
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 600 Fourth St. South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727 803-8747 ext 3028
Contact_Facsimile_Telephone: 727 803-2030
Contact_Electronic_Mail_Address: hhenkel@usgs.gov
Resource_Description: Water Budget Data
Distribution_Liability: No warrantees are implied or explicit for the data
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ASCII
Format_Specification: tab-delimited text files
Format_Information_Content:
Each file contains data for one of the four sites sampled for water budget
Transfer_Size: 2.8
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: <https://sofia.usgs.gov/exchange/german/germanwb.html>
Access_Instructions: Data may be downloaded from the SOFIA website
Fees: none

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Sandra Kinnaman
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 12703 Research Parkway
City: Orlando
State_or_Province: FL
Postal_Code: 32826
Country: USA
Contact_Voice_Telephone: 407 803-5541
Contact_Electronic_Mail_Address: kinnaman@usgs.gov
Resource_Description: Rainfall Data
Distribution_Liability: No warrantees are implied or explicit for the data
Standard_Order_Process:
Non-digital_Form: unknown
Fees: none
Ordering_Instructions: For this data, please contact Sandra Kinnaman

Metadata_Reference_Information:
Metadata_Date: 20101101
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather Henkel
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing and physical address
Address: 600 Fourth Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727 803-8747 ext 3028
Contact_Facsimile_Telephone: 727 803-2030
Contact_Electronic_Mail_Address: sofia-metadata@usgs.gov
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Access_Constraints: none
Metadata_Use_Constraints:
This metadata record may have been copied from the SOFIA website and may not be the most recent version. Please check <https://sofia.usgs.gov/metadata> to be sure you have the most recent version.

This page is <https://sofia.usgs.gov/metadata/sflwww/german_et_04.html>

U.S. Department of the Interior, U.S. Geological Survey
Comments and suggestions? Contact: Heather Henkel - Webmaster
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