University of Texas at Austin

Dr. Todd Caldwell

Dr. Todd Caldwell

Dr. Todd Caldwell

Research Scientist
Bureau of Economic Geology
The University of Texas at Austin
University Station, Box X
Austin, Texas 78713-8924
  • Research Interests

    Transport of water, solute, and heat through the vadose zone

    Soil, sediment and dust characterization

    Numerical modeling and parameter optimization of soil-atmosphere-plant systems

    Disturbed soils and ecosystem restoration

    Soil geomorphology and landscape evolution

  • Education

    Ph.D. Hydrogeology, University of Nevada, Reno, 2011

    M.S. Hydrogeology, University of Nevada, Reno, 1999

    B.S. Geology, University of New Mexico, 1997

  • Professional History

    2012–present Research Associate, Bureau of Economic Geology

    2011–2012 Assistant Research Professor, Desert Research Institute

    2001–2011 Research Scientist, Desert Research Institute

    2000–2001 Hydrologist, Pacific Northwest National Laboratory

  • Selected Publications

    Google Scholar H-Index of 18; ISI H-Index of12, Researcher ID: H‐5129‐2011

    Young, M. H., J. Andrews, T. G. Caldwell, and K. Saylam (2017), Airborne LiDAR and aerial imagery to assess potential burrow locations for the desert tortoise (Gopherus agassizii), Remote Sens., 9, 458.

    Clewley, D., J. Whitcomb, R. Akbar, A. H. C. Silva, A. Berg, J. Adams, T. G. Caldwell, D. Entekhabi, and M. Moghaddam (2017), A method for upscaling in situ soil moisture measurements to satellite footprint scale using Random Forests, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, X, XX.

    Ouellette, J. D., J. T. Johnson, A. Balenzano, F. Mattia, G. Satalino, S. B. Kim, R. S. Dunbar, A. Colliander, M. H. Cosh, T.G. Caldwell, J. P. Walker, and A. A. Berg (2017), A time-series approach to estimating soil moisture from vegetated surfaces using L-Band radar backscatter, IEEE Trans. Geosci. Remote Sens., PP, 1-8, 10.1109/TGRS.2017.2663768.

    Kim, S. B., J. J. van Zyl, J. T. Johnson, M. Moghaddam, L. Tsang, A. Colliander, R. S. Dunbar, T. J. Jackson, S. Jaruwatanadilok, R. West, A. Berg, T. G. Caldwell, M. H. Cosh, D. C. Goodrich, S. Livingston, E. López-Baeza, T. Rowlandson, M. Thibeault, J. P. Walker, D. Entekhabi, E. G. Njoku, P. E. O' Neill, and S. H. Yueh (2017), Surface soil moisture retrieval using the L-band synthetic aperture radar onboard the Soil Moisture Active Passive (SMAP) satellite and evaluation at core validation sites, IEEE Trans. Geosci. Remote Sens., 1-18, 10.1109/TGRS.2016.2631126.

    Degré, A., M. J. van der Ploeg, T. G. Caldwell, and H. P. A. Gooren (2017), Comparison of soil water potential sensors: A drying experiment, Vadose Zone J., 16, 10.2136/vzj2016.08.0067.

    Colliander, A., T. J. Jackson, R. Bindlish, S. Chan, N. Das, S. B. Kim, M. H. Cosh, R. S. Dunbar, L. Dang, L. Pashaian, J. Asanuma, K. Aida, A. Berg, T. Rowlandson, D. Bosch, T. G. Caldwell, K. Caylor, D. Goodrich, H. al Jassar, E. Lopez-Baeza, J. Martínez-Fernández, A. González-Zamora, S. Livingston, H. McNairn, A. Pacheco, M. Moghaddam, C. Montzka, C. Notarnicola, G. Niedrist, T. Pellarin, J. Prueger, J. Pulliainen, K. Rautiainen, J. Ramos, M. Seyfried, P. Starks, Z. Su, Y. Zeng, R. van der Velde, M. Thibeault, W. Dorigo, M. Vreugdenhil, J. P. Walker, X. Wu, A. Monerris, P. E. O'Neill, D. Entekhabi, E. G. Njoku, and S. Yueh (2017), Validation of SMAP surface soil moisture products with core validation sites, Remote Sens. Environ., 191, 215-231, DOI: 10.1016/j.rse.2017.01.021

    Abolt, C. J., M. H. Young, and T. G. Caldwell (2017), Numerical modelling of ice-wedge polygon geomorphic transition, Permafrost and Periglac. Process., 28, 347-355.

    Shellito, P. J., E. E. Small, A. Colliander, R. Bindlish, M. H. Cosh, A. A. Berg, D. D. Bosch, T. G. Caldwell, D. C. Goodrich, H. McNairn, J. H. Prueger, P. J. Starks, R. van der Velde, and J. P. Walker (2016), SMAP soil moisture drying more rapid than observed in situ following rainfall events, Geophys. Res. Letters, 43(15), 8068-8075, doi: 10.1002/2016gl069946.

    Chan, S., R. Bindlish, P. O’Neill, E. Njoku, T. Jackson, A. Colliander, F. Chen, M. Burgin, S. Dunbar, J. Piepmeier, S. Yueh, D. Entekhabi, M. Cosh, T.G. Caldwell, J. Walker, X. Wu, A. Berg, T. Rowlandson, A. Pacheco, H. McNairn, M. Thibeault, J. Martínez-Fernández, A. González-Zamora, M. Seyfried, D. Bosch, P. Starks, D. Goodrich, J. Prueger, M. Palecki, E.E. Small, M. Zreda, J. Calvet, W. Crow, and Y. Kerr (2016), Assessment of the SMAP Level 2 Passive Soil Moisture Product, IEEE Trans. Geosci. Remote Sens., 54, 4994-5007, 10.1109/TGRS.2016.2561938.

    Zhu, J., D. Sun, M.H. Young, T.G. Caldwell, and F. Pan (2015), Shrub spatial organization and partitioning of evaporation and transpiration in arid environments, Ecohydrology, DOI: 10.1002/eco.1576.

    Rau, B.M., J.C. Chambers, D.A. Pyke, B.A. Roundy, E.W. Schupp, P. Doescher, and T.G. Caldwell (2014), Soil resources influence vegetation and response to fire and fire-surrogate treatments in sagebrush-steppe ecosystems, Rangeland Ecology & Management, doi: 10.2111/REM-D-14-00027.1

    Caldwell, T.G., T. Wöhling, M.H. Young, D.P. Boyle, and E.V. McDonald (2013), Characterizing disturbed desert soils using multiobjective parameter optimization, Vadose Zone J. doi:10.2136/vzj2012.0083.

    Caldwell, T.G., M.H. Young, E.V. McDonald, and J. Zhu (2012),Soil heterogeneity in arid shrublands: Biotic and abiotic processes, Water Resour. Res.,48, W09551, doi:10.1029/2012WR011963.

    Flerchinger, G.N., T.G. Caldwell, J. Cho, S.P. Hardegree (2012), The Simultaneous Heat and Water Model: Model use, calibration and validation, Trans. ASABE, 55, 1395-1411.

    Rau, B.M., D.W. Johnson, R.R. Blank, A. Lucchesi, T.G. Caldwell, and E.W. Schupp (2011), Transition from sagebrush steppe to annual grass (Bromus tectorum): Influence on belowground carbon and nitrogen, Rangeland Ecology & Management, 64, 139-147.

    Rau, B.M., D.W. Johnson, R.R. Blank, R.J. Tausch, B.A. Roundy, R.F. Miller, T.G. Caldwell, and A. Lucchesi (2011), Woodland expansion’s influence on belowground carbon and nitrogen in the Great Basin U.S, J. Arid Environ., 10.1016/j.jaridenv.2011.04.005.

    Wilcox, B.P., L. Turnbull, M.H. Young, C.J. Williams, S. Ravi, M.S. Seyfried, D.R. Bowling, R.L. Scott, M.J. Germino, T.G. Caldwell, and J. Wainwright (2011), Invasion of shrublands by exotic grasses: ecohydrological consequences in cold versus warm deserts, Ecohydrology, 10.1002/eco.247.

    Bacon, S.N., E.V. McDonald, T.G. Caldwell, and G.K. Dalldorf (2010), Timing and distribution of alluvial fan sedimentation in response to strengthening of the late Holocene ENSO variability in the Sonoran Desert, southwestern Arizona, USA, Quaternary Research, 73, 425-438.

    Caldwell, T.G., D.W. Johnson, W.W. Miller, R.G. Qualls, and R.R. Blank (2009), Prescription fire and anion retention in Tahoe forest soils. Soil Sci., 174, 594-600. 

    Caldwell, T.G., E.V. McDonald, and M.H. Young (2009), The seedbed microclimate and active revegetation of disturbed lands in the Mojave Desert, J. Arid Environments 73, 563-573.

    Young, M.H., T.G. Caldwell, D.G. Meadows, and L.F. Fenstermaker (2009), Variability of soil physical and hydraulic properties at the Mojave Global Change Facility, Nevada: Implications for water budget and evapotranspiration, J. Arid Environ. 73, 733-744.

    Caldwell, T.G., M.H. Young, J. Zhu, and E.V. McDonald (2008), Spatial structure of hydraulic properties from canopy to interspace in the Mojave Desert, Geophys. Res. Lett. 35, L19406, doi:10.1029/2008GL035095.

    Caldwell, T.G., E.V. McDonald, S.N. Bacon, and G. Stullenbarger (2008), The performance and sustainability of vehicle dust courses for desert military testing, J. Terramechanics,45, 213-221.

    Bacon, S.N., E.V. McDonald, S. Baker, T.G. Caldwell, and G. Stullenbarger (2008),Desert terrain characterization of landforms and surface cover within vehicle test courses at U.S. Army Yuma Proving Ground, USA, J. Terramechanics,45, 167-183.

    Shafer, D.S., M.H. Young, S.F. Zitzer, T.G. Caldwell and E.V. McDonald (2007), Interrelated pedogenic, hydraulic, biotic and abiotic processes during the past 125 000 years of landscape evolution in the northern Mojave Desert, Nevada, USA, J. Arid Environ., 69, 633-657.

    Caldwell, T.G., E.V. McDonald, and M.H. Young (2006), Soil disturbance and hydrologic response at the National Training Center, Ft. Irwin, California, J. Arid Environ., 67, 456-472.

    Johnson, D.W., R.B. Susfalk, T.G. Caldwell, J.D. Murphey, W.W. Miller, and R.F. Walker (2004), Fire effects on carbon and nitrogen budgets in forests, Water Air Soil Pollut. 4, 263-275.

    Young, M.H., E.V. McDonald, T.G. Caldwell, S.G. Benner, and D.G. Meadows (2004), Hydraulic properties of a desert soil chronosequence in the Mojave Desert, USA, Vadose Zone J., 3, 956-963.
    Caldwell, T.G., D.W. Johnson, W.W. Miller, and R.G. Qualls (2002), Forest floor carbon and nitrogen losses due to prescription fire, Soil Sci. Soc. Amer. J., 66, 262-267.

    Gee, G.W., A.L. Ward, T.G. Caldwell, and J.C. Ritter (2002), A vadose zone water fluxmeter with divergence control, Water Resour. Res., 38, 10.1029/2001WR000816.

    Sisson, J.B., W.L. Bratton, G.W. Gee, J.M. Hubbell, J.C. Ritter, and T.G. Caldwell (2002), Advances in tensiometry for long-term monitoring of soil water pressures, Vadose Zone J., 1, 310-315.

    Johnson, D.W., R.B. Susfalk, R.A. Dahlgren, T.G. Caldwell, and W.W. Miller (2001), Nutrient fluxes in a snow-dominated, semi-arid forest: Spatial and temporal patterns, Biogeochem., 55, 219-245