TITLE: CEOP First Half EOP-3 GAPP Oak Ridge, TN Flux Data Set CONTACT: Tilden P. Meyers Atmospheric Turbulence and Diffusion Division 456 S. Illinois Ave. Oak Ridge, TN 37830 Telephone: (865) 576-1245 Fax: (865) 576-1327 E-Mail: email@example.com 1.0 DATA SET OVERVIEW This data set contains 30-minute resolution flux data from the Coordinated Enhanced Observing Period (CEOP) Global Energy and Water Cycle Experiment (GEWEX) Americas Prediction Project (GAPP) Reference Site operated by Tilden Meyers (National Oceanic and Atmospheric Administration (NOAA) Atmospheric Turbulence and Diffusion Division (ATDD) at Oak Ridge, Tennessee. This data set covers the time period 1 October 2002 through 31 March 2003. Further information about the Oak Ridge flux tower is available at the following URL: http://www.atdd.noaa.gov/gewex.htm 1.1 Site Information The Oak Ridge reference site is located on the Walker Branch Watershed. The vegetation is a deciduous forest of the eastern hardwood type. The leaf area index varies seasonally with a maximum value of about 5. The canopy height is 24-26 m. The flux measurement height is 38 m. The flux tower is located at 35.9583 N and 84.2916 W at an elevation of 326 m. This data set includes observations of CO2 flux, sensible heat flux, and latent heat flux at 38.0 m height. Also included is soil heat flux at the -0.04 m height. 2.0 INSTRUMENTATION DESCRIPTION No information is currently available on the make, model or specifications of the instrumentation used at the Oak Ridge, TN reference site. 3.0 DATA COLLECTION AND PROCESSING 3.1 NOAA/ATDD Data Collection and Processing Main computer: Shuttle SpaceWalker Mini-Barebones System with 250 MB Internal Zip Disk. This is a neat computer box, measuring 270 mm x 190 mm x 170 mm. It provides a VIA chipset and supports Intel PIII/Celeron/VIA C3 processors. It has two PC133 memory slots, an onboard 2D/3D graphics engine, two onboard IEEE 1394 ports (FireWire), four Universal Serial Bus (USB) ports, one onboard 10/100 MB LAN port, and one onboard AC '97 audio interface. It also includes S-video and TV-out jacks, two 3.5" drive bays, one 5.25 inch drive bay, and one PCI slot which utilizes a riser card. Serial Interface: Keyspan USB 4-port serial adapter. This provides four RS-232 serial ports in an easily expandable box. The com port connections are described below: Com 1 - RM Young ultrasonic anemometer. The sonic provides 10 Hz U, V, W winds and air temperature. In addition, an ATDD IRGA is used to measure CO2 and H2O concentrations through the sonic anemometer's built-in A/D system. Com 2 - Campbell Scientific CR10/23X Data Logger. The data logger collects up to 15 channels of analog data and stores at 1 Hz. All data collected by the data logger are downloaded to the Linux computer once per day. Typical data measured include soil moisture and temperature, mean wind speed and direction from an RM Young propeller anemometer, rainfall data, solar radiation, and air pressure and temperature. Com 3 - Olympus Camedia digital camera. This camera provides images of the site once per hour from 8:00 am until 6:00 pm. These images are archived on the 250MB removable Zip disk. Com 4 - Motorola Cell-Modem back phone. The cellular phone modem is connected to Com 4 allowing remote access from a dial-up line. Routine data downloads and maintenance is performed using dial-up services provided by Kermit. The Linux software has been developed in-house. REA Applications An extended application of the GEWEX hardware and software involves the use of Relaxed Eddy Accumulation to measure fluxes of trace gases that cannot be easily measured at high frequency in real-time (e.g. Mercury, Methane, Sulfur, etc). The software control for the REA system is quite unique and simple. The control of the up, mid, and down sampling valves is performed using the RS-232 control lines CTS (Clear-To-Send) and DTR (Data-Terminal-Ready). By toggling these two lines high and low, four combinations can be obtained. This is easily accomplished in software and conveniently uses the vertical winds measured from the sonic anemometer. 3.2 UCAR/JOSS Data Processing The University Corporation for Atmospheric Research/Joint Offfice for Science Support (UCAR/JOSS) converted the data from the raw format provided by NOAA/ATDD into the CEOP EOP-3 data format agreed to by the CEOP Scientific Steering Committee. This format is described in detail as part of the CEOP Reference Site Data Set Procedures Report which is available at the following URL: http://www.joss.ucar.edu/ghp/ceopdm/refdata_report/ceop_flux_format.html 4.0 QUALITY CONTROL PROCEDURES 4.1 NOAA/ATDD Quality Control Procedures No information is currently available on the NOAA/ATDD quality control procedures conducted on the Oak Ridge reference site data. 4.2 UCAR/JOSS Quality Control Procedures UCAR/JOSS conducted two primary quality assurrance/control procedures on the Oak Ridge reference site data. First the data has been evaluated by a detailed QA algorithm that verifies the format is correct, examines any QC flags, and conducts basic checks on data values. Second, JOSS conducts a manual inspection of time series plots of each parameter. UCAR/JOSS did not apply any QC flags to the Oak Ridge reference site data. 5.0 GAP FILLING PROCEDURES No information is currently available on any gap filling procedures that may have been conducted on the Oak Ridge reference site data. 6.0 DATA REMARKS No data remarks. 7.0 REFERENCE REQUIREMENTS No information is currently available on any reference requirements for the Oak Ridge reference site data. 8.0 REFERENCES None.