1.0 DOCUMENT INFORMATION
1.1 Document Title: TDE Soil Water Data By TDR
1.2 Revision Date: August 23, 2005
1.3 Document Summary: Periodic measurements of soil water
content by TDR 1993-2005.
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)2.2 Title Of Investigation:
Environmental Sciences Division
Oak Ridge National Laboratory
Building 1059, P.O. Box 2008
Oak Ridge, TN 37831-6422
3.0 DATA SUMMARY
Mean daily soil water content data for the TDE treatment plots
including
data for the 0-35 cm depth, 0-70 cm depth and derived data for the
35-70
cm depth. Estimates of soil water potential for the 0-35 and
35-70
depth increments are also provided.
4.0 PROCEDURES
Soil water content (%, v/v) was measured with a time domain
reflectometer
(TDR; Soil Moisture Equipment Corp., Santa Barbara, California)
following
the procedure of Topp and Davis (1985) as documented for soils with
high
coarse fraction content (Drungil et al. 1987). Three hundred ten
sampling locations were installed at an 8 x 8 meter spacing across the
site giving more than 100 soil water monitoring locations per
plot.
At each location two pairs of TDR waveguides were installed in a
vertical
orientation (0-0.35 and 0-0.7 m). The surface (0-0.35 m) TDR
measurements
coincide with the zone of maxium root density in these soils. TDR
measurements were obtained biweekly during the growing season and
approximately
monthly during the dormant season. The TDR soil water content
measurements
were adjusted for the coarse fraction of these soils (mean coarse
fraction
of 14%) and converted to soil water potentials using laboratory derived
soil moisture retention curves for the A, A/E and E/B horizons (Hanson
et al. 1998).
Starting in 2002 the spatial detail of the soil water content
observations was scaled back, and the measurements were only collected
for a single upper, middle and lower transect across the TDE site.
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 2 = RDOY
Running day of the year since January 1, 1993
Column 3 = DOY
Day of the year (1-365 or 366)
Column 4 = W35wc
Mean 'wet' plot water content of the 0 to 35 cm depth incrrement in
% v/v
Column 5 = A35wc
Mean 'ambient' plot water content of the 0 to 35 cm depth incrrement
in % v/v
Column 6 = D35wc
Mean 'dry' plot water content of the 0 to 35 cm depth incrrement in
% v/v
Column 7 = W35wp
Mean 'wet' plot water potential of the 0 to 35 cm depth incrrement
in MPa
Column 8 = A35wp
Mean 'ambient' plot water potential of the 0 to 35 cm depth incrrement
in MPa
Column 9 = D35wp
Mean 'dry' plot water potential of the 0 to 35 cm depth incrrement
in MPa
Column 10 = W70wc
Mean 'wet' plot water content of the 0 to 70 cm depth incrrement in
% v/v
Column 11 = A70wc
Mean 'ambient' plot water content of the 0 to 70 cm depth incrrement
in % v/v
Column 12 = D70wc
Mean 'dry' plot water content of the 0 to 70 cm depth incrrement in
% v/v
Column 13 = W3570wc
Mean 'wet' plot water content of the 35 to 70 cm depth incrrement in
% v/v
Column 14 = A3570wc
Mean 'ambient' plot water content of the 35 to 70 cm depth incrrement
in % v/v
Column 15 = D3570wc
Mean 'dry' plot water content of the 35 to 70 cm depth incrrement in
% v/v
Column 16 = W3570wp
Mean 'wet' plot water potential of the 35 to 70 cm depth incrrement
in MPa
Column 17 = A3570wp
Mean 'ambient' plot water potential of the 35 to 70 cm depth incrrement
in MPa
Column 18 = D3570wp
Mean 'dry' plot water potential of the 35 to 70 cm depth incrrement
in MPa
7.0 KNOWN ERRORS AND QUALITY ASSESSMENT
These daily data and the original hourly data from which they were
derived 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.
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, 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
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 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 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.
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.
TDR soil water content data 1993 through August 22,
2005