Hourly Weather Data for the Walker Branch
Throughfall Displacement Experiment

1.0 DOCUMENT INFORMATION
1.1 Document Title: TDE hourly weather data
1.2 Revision Date:  30 April 2007
1.3 Document Summary:  Hourly weather variables from the TDE site for 1993 through 2006.
1.4 Sponsor: Office of Biological and Environmental Research, U. S. DOE

 2.0 INVESTIGATOR
2.1 Investigator and data set contact:

P.J. Hanson (hansonpj@ornl.gov)
Research Staff Member
Environmental Sciences Division
Oak Ridge National Laboratory
Building 1059, Bethel Valley Road
Oak Ridge, TN 37831-6422

 3.0 DATA SUMMARY
Hourly integrated or averaged values for incident photosynthetically active radiation, incident total radiation, air temperature, relative humidity, rainfall, and soil temperature at  10-15 cm.

 4.0 PROCEDURES
Measurements of incoming rainfall, irradiance (Pyranometer sensor, LiCor Inc.) and photosynthetic photon flux density (Quantum sensor, LiCor Inc.) were obtained in a nearby clearing until 1998 when above canopy observations were added to the ambient plot tower. Clearing data were used to represent "above-canopy" conditions for the experimental site for the years 1993-1997. Two tipping bucket rain gauges with 3 m extension troughs attached are installed on each plot to evaluate the amount of throughfall reaching the forest floor. Sub-canopy air temperatures (2 stations per treatment plot) are made at approximately 1 m of height in a location shielded from direct solar radiation. Soil temperatures are measured at two depths (15 and 35 cm) and 4 locations per plot. All temperatures are measured with thermistors. Climate data are collected as hourly means and logged on data loggers (Li-1000, LiCor Inc.) housed in instrument enclosures located at one upslope and one downslope location per treatment plot, and one enclosure in the nearby clearing.

 5.0 OBSERVATION NOTES
None

 6.0 DATA ORGANIZATION

Data are provided in comma delimeted text files where the first line includes the variable names and subsequent lines include the following data by month.

6.1 Variable, Definition, and Units

Column 1 = MOY
  Month of the year (1-12)

Column 2 = DOY
  Day of the year (1-365 or 366)

Column 3 = DFOY
  Day fraction of the year (1.00 to 365.00)

Column 4 = HOY
  Hour of the year (1-8760 or 8784 in a leap year)

Column 5 = Quan
  Mean incident photosynthetically active radiation (PAR) in µmol m-2 s-1

Column 6 = Pyran
 Mean incident hourly radiation in W m-2 or (J s-1 m-2)

Column 7 = Uquan
  Mean hourly understory (1.5 m) PAR in µmol m-2 s-1

Column 8 = AT
  Hourly mean air temperature in degrees C

Column 9 = RH
  Hourly mean relative humidity in percent

Column 10 = RN
  Hourly rainfall in mm

Column 11 = Wind
  Mean hourly wind speed in m s-1.

Values from 1993 through 1997 are from 37 m on the the Oak Ridge Ameriflux tower (10 m above the canopy).  A value of 1.5 m s-1 is used to fill in for missing hours for those years.  Values for 1998 through 2000 are from the ambient plot tower on the TDE experimental site and the anemometer is nearer to the canopy (? m).


Column 12 = ST
  Mean 1 hour soil temperature (10-15 cm) in degrees C

Column 13 = VPD
  Mean vapor pressure deficit in kPa.

Column 14 = SWisis
  Mean incident shortwave radiation in W m-2 measured with an Eppley radiometer located 44 m above the forest canopy.  These data are not available for 1993 and 1994.

 7.0 KNOWN ERRORS AND QUALITY ASSESSMENT
The hourly data have been checked for errors and missing data. If bad or missing data were found approximate replacement data were obtained from other weather data sources in the area if possible to provide the most complete data set.

8.0 NOTES
8.1 Limitations of the data:     None.
8.2 Known Problems With The Data:     None.
8.3 Usage Guidance:     None.

 9.0 REFERENCES:

Hanson PJ, Todd DE, Huston MA (2003) Walker Branch Throughfall Displacement Experiment (TDE) In: Hanson PJ, Wullschleger SD, Eds, North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. Springer, New York, pp. 8-31.

Hanson, P.J. , D.E.Todd and J.S. Amthor. 2001. A six year study of sapling and large-tree growth and mortality responses to natural and induced variability in precipitation and throughfall.   Tree Physiology 21: 345-358.

Hanson P.J. 2000.  Large-scale Water Manipulations -- chapter 23 In: O.E. Sala, R.B. Jackson, H.A. Mooney, and R.W. Howarth, eds.  Methods in Ecosystem Science, Springer-Verlag, New York.  pp. 341-352.

Hanson, P.J., D.E. Todd, N.T. Edwards, and M.A. Huston.  1995.  Field performance of the Walker Branch Throughfall Displacement Experiment,   In:  A. Jenkins, R.C. Ferrier, and C. Kirby, eds., Ecosystem Manipulation Experiments: scientific approaches, experimental design and relevant results, Ecosystem Research Report #20, Commission of the European Communities, pp. 307-313.

Hanson, P.J., D.E. Todd, M.A. Huston, J.D. Joslin, Jennifer Croker, and R. M. Augé. 1998.  Description and field performance of the Walker Branch Throughfall Displacement Experiment: 1993-1996, ORNL/TM-13586, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
None

 10.0 DATA LISTING

Click on the following to view data for the listed year.
Once open the files can exported as text files with the 'Save As' command.

Hourly data for 1993
Hourly data for 1994
Hourly data for 1995
Hourly data for 1996
Hourly data for 1997
Hourly data for 1998
Hourly data for 1999
Hourly data for 2000
Hourly data for 2001
Hourly data for 2002
Hourly data for 2003
Hourly data for 2003 with modified quantum values 30 Apr 2007
Hourly data for 2004
Hourly data for 2004 with modified quantum values 30 Apr 2007
Hourly data for 2005
Hourly data for 2005 with modified quantum values 30 Apr 2007
Hourly data for 2006