The authors are thankful to Kang Nai at the University of Oklahoma for data preparations. The data were kindly provided by the Atmospheric Radiation Measurement (ARM) Program. Comments and suggestions from Dr. Jeff Basara at the University of Oklahoma and anonymous reviewers improved the presentation of the results. The first two authors acknowledge the support by Chinese NSF Grant E-D0119-90202014 to Lanzhou University.
Al Nakhabandi, G., and H. Kohnke. 1965. Thermal conductivity and diffusivity of soil as related to moisture tension and other physical properties. Agric. Meteor. 2:271–279.
Cahill, A. T., , F. Ungaro, , M. B. Parlange, , M. Mata, , and D. R. Nielsen. 1999. Combined spatial and Kalman filter estimation of optimal soil hydraulic properties. Water Resour. Res. 35:1079–1088.
Cane, M. A., , A. Kaplan, , R. N. Miller, , B. Tang, , E. C. Hackert, , and A. J. Busalacchi. 1996. Mapping tropical Pacific sea level: Data assimilation via a reduced state space Kalman filter. J. Geophys. Res. 101:22599–22617.
Cosby, B. J., , G. M. Hornberger, , R. B. Clapp, , and T. R. Ginn. 1984. A statistical exploration of the relationships of soil moisture characteristics to the physical properties of soils. Water Resour. Res. 20:682–690.
Deardorff, J. W. 1978. Efficient prediction of ground surface temperature and moisture with inclusion of a layer of vegetation. J. Geophys. Res. 83 C4:1889–1903.
de Vries, D. A. 1975. Heat transfer in soils. Transfer Processes in the Plant Environment, Part 1, Heat and Mass Transfer in the Biosphere, D. A. de Vries and N. H. Afgan, Eds., John Wiley and Sons, 4–28.
Ek, M., and R. H. Cuenca. 1994. Variation in soil parameters: Implications for modeling surface fluxes and atmospheric boundary-layer development. Bound.-Layer Meteor. 70:369–383.
Mancini, M., , R. Hoeben, , and P. A. Troch. 1999. Multifrequency radar observations of bare surface soil moisture content: A laboratory experiment. Water Resour. Res. 35:1827–1838.
McCumber, M. C., and R. A. Pielke. 1981. Simulation of effects of surface fluxes of heat and moisture in a mesoscale numerical model. J. Geophys. Res. 86 C10:9929–9938.
Milly, P. C. D. 1982. Moisture and heat transport of hysteretic, inhomogeneous porous media: A matric head-based formulation and a numerical model. Water Resour. Res. 18:489–498.
Montaldo, N., and J. D. Albertson. 2003. Multi-scale assimilation of surface soil moisture data for robust root zone moisture predictions. Adv. Water Resour. 26:33–44.
Parlange, M. B., , G. G. Katul, , R. H. Cuenca, , M. L. Kavvas, , D. R. Nielsen, , and M. Mata. 1992. Physical basis for a time series model of soil water content. Water Resour. Res. 28:2437–2446.
Parlange, M. B., , G. G. Katul, , M. V. Folegatti, , and D. R. Nielsen. 1993. Evaporation and the field scale water diffusivity function. Water Resour. Res. 29:1279–1286.
Peters-Lidard, C. D., , E. Blackburn, , X. Liang, , and E. F. Wood. 1998. The effect of soil thermal conductivity parameterization on surface energy fluxes and temperatures. J. Atmos. Sci. 55:1209–1224.
Reece, C. F. 1996. Evaluation of a line heat dissipation sensor for measuring soil matric potential. Soil Sci. Soc. Amer. J. 60:1022–1028.
Schneider, J. M., , D. K. Fisher, , R. L. Elliott, , G. O. Browen, , and C. P. Bahrmann. 2003. Spatiotemporal variation in soil water: First results from the ARM SGP CART network. J. Hydrometeor. 4:106–120.
Starks, P. J., and T. J. Jackson. 2001. Remote sensing and estimation of root zone water content. Remote Sensing and Hydrology 2000, M. Owe et al., Eds., IAHS Publication 267, 409–411.
Ungar, S. G., , R. Layman, , J. E. Campbell, , J. Walsh, , and H. J. McKim. 1992. Determination of soil moisture distribution from impedance and gravimetric measurements of soil moisture in FIFE. J. Geophys. Res. 97:18979–18985.
Van Geer, F. C., , C. B. M. Te Stroet, , and Y. Zhou. 1991. Using Kalman filtering to improve and quantify the uncertainty of numerical groundwater simulations: 1. The role of system noise and its calibration. Water Resour. Res. 27:1987–1994.
Viterbo, P., and A. C. M. Beljaars. 1995. An improved land surface parameterization scheme in the ECMWF model and its validation. J. Climate 8:2716–2748.
Xu, Q., and B. Zhou. 2003. Retrieving soil moisture from soil temperature measurements by using linear regression. Adv. Atmos. Sci. 20:849–858.
Xu, Q., , B. Zhou, , S. D. Burk, , and E. H. Barker. 1999. An air–soil layer coupled scheme for computing surface heat fluxes. J. Appl. Meteor. 38:211–223.