Beven, K. J. and Kirkby, M. J.: A physically based, variable contributing area model of basin hydrology, Hydrological Sciences Bulletin, 24, 43–69, 1979.
Brent, R.: Algorithms for Minimization without Derivatives, Prentice-Hall, Englewood Cliffs, New Jersey, 1973.
Brocca, L., Melone, F., Moramarco, T., and Singh, V. P.: Assimilation of observed soil moisture data in storm rainfall-runoff modeling, J. Hydrol. Eng., 14, 153–165, 2009.
Crow, W. T. and Ryu, D.: A new data assimilation approach for improving runoff prediction using remotely-sensed soil moisture retrievals, Hydrol. Earth Syst. Sci., 13, 1–16, https://doi.org/10.5194/hess-13-1-2009, 2009.
Davidson, M. W. J., Le Toan, T., Mattia, F., Satalino, G., Manninen, T., and Borgeaud, M.: On the characterization of agricultural soil roughness for radar remote sensing studies, IEEE T. Geosci. Remote Sens., 38, 630–640, 2000.
De Baets, B. and De Meyer, H.: Transitivity-preserving fuzzification schemes for cardinality-based similarity measures, Eur. J. Oper. Res., 160, 726–740, 2005.
De Lannoy, G. J. M., Houser, P. R., Pauwels, V. R. N., and Verhoest, N. E. C.: State and bias estimation for soil moisture profiles by an E}nsemble {K}alman filter, Water Resour. Res., 43, {W}06401, https://doi.org/10.1029/2006WR005100, 2007{a.
De Lannoy, G. J. M., Reichle, R. H., Houser, P. R., Pauwels, V. R. N., and Verhoest, N. E. C.: Correcting for forecast bias in soil moisture assimilation with the E}nsemble {K}alman filter, Water Resour. Res., 43, {W}09410, https://doi.org/10.1029/2006WR005449, 2007{b.
Dobson, M. C., Ulaby, F. T., Hallikainen, M. T., and El-Rayes, M. A.: Microwave dielectric behavior of wet soil, part II: Dielectric mixing models, IEEE T. Geosci. Remote Sens., 23, 35–46, 1985.
Famiglietti, J., Ryu, D., Berg, A. A., Rodell, M., and Jackson, T. J.: Field observations of soil moisture variability across scales, Water Resour. Res., 44, {W}01423, https://doi.org/10.1029/2006WR005804, 2008.
Fung, A. K.: Microwave Scattering and Emission Models and their Applications, Artech House, Norwood, MA, 1994.
Guyonnet, D., Bourgine, B., Dubois, D., Fargier, H., Côme, B., and Chilès, J. P.: Hybrid approach for addressing uncertainty in risk assessments, J. Environ. Eng., 129, 68–78, https://doi.org/10.1061/(ASCE)0733-9372(2003)129:1(68), 2003.
Hoeben, R. and Troch, P. A.: Assimilation of active microwave observation data for soil moisture profile estimation, Water Resour. Res., 36, 2805–2819, 2000.
Hupet, F. and Vanclooster, M.: Intraseasonal dynamics of soil moisture variability within a small agricultural maize cropped field, J. Hydrol., 261, 86–101, 2002.
Ivanov, V. Y., Fatichi, S., Jenerette, G. D., Espeleta, J. F., Troch, P. A., and Huxman, T. E.: Hysteresis of soil moisture spatial heterogeneity and the "homogenizing" effect of vegetation, Water Resour. Res., 46, {W}09521, https://doi.org/10.1029/2009WR008611, 2010.
Lievens, H., Vernieuwe, H., \'{Alvarez-Mozos}, J., De Baets, B., and Verhoest, N. E. C.: Error in radar-derived soil moisture due to roughness parameterization: an analysis based on synthetical surface profiles, Sensors, 9, 1067–1093, https://doi.org/10.3390/s90201067, 2009.
Mallants, D., Jacques, D., Vanclooster, M., Diels, J., and Feyen, J.: A stochastic approach to simulate water flow in macroporous soil, Geoderma, 70, 299–324, 1996.
Mattia, F., Davidson, M. W. J., Le Toan, T., D'Haese, C. M. F., Verhoest, N. E. C., Gatti, A. M., and Borgeaud, M.: A comparison between soil roughness statistics used in surface scattering models derived from mechanical and laser profilers, IEEE T. Geosci. Remote Sens., 41, 1659–1671, 2003.
Merlin, O., Chechbouni, A., Boulet, G., and Kerr, Y.: Assimilation of disaggregated microwave soil moisture into a hydrologic model using coarse-scale meteorological data, J. Hydrometeorol., 7, 1308–1322, 2006.
Minet, J., Laloy, E., Lambot, S., and Vanclooster, M.: Effect of high-resolution spatial soil moisture variability on simulated runoff response using a distributed hydrologic model, Hydrol. Earth Syst. Sci., 15, 1323–1338, https://doi.org/10.5194/hess-15-1323-2011, 2011a.
Minet, J., Wahyudi, A., Bogaert, P., Vanclooster, M., and Lambot, S.: Mapping shallow soil moisture profiles at the field scale using full-waveform inversion of ground penetrating radar data, Geoderma, 161, 225–237, 2011{b}.
Nguyen, H. T.: A note on the extension principle for fuzzy sets, J. Math. Anal. Appl., 64, 369–380, 1978.
Nyberg, L.: Spatial variability of soil water content in the covered catchment at Gårdsjön, Sweden, Hydrol. Process., 10, 80–103, 1996.
Oh, Y. and Kay, Y. C.: Condition for precise measurement of soil surface roughness, IEEE T. Geosci. Remote Sens., 36, 691–695, 1998.
Pauwels, V. R. N., Hoeben, R., Verhoest, N. E. C., and De Troch, F. P.: The importance of the spatial patterns of remotely sensed soil moisture in the improvement of discharge predictions for small-scale basins through data assimilation, J. Hydrol., 251, 88–102, 2001.
Penna, D., Borga, M., Norbiato, D., and Fontana, G.: Hillslope scale soil moisture variability in a steep alpine terrain, J. Hydrol., 364, 311–327, 2009.
Ryu, D. and Famiglietti, J. S.: Characterization of footprint-scale surface soil moisture variability using Gaussian and beta distribution functions during the Southern Great Plains 1997 (SGP97) hydrology experiment, Water Resour. Res., 41, {W}12433, https://doi.org/10.1029/2004WR003835, 2005.
Salvucci, G.: Limiting relations between soil moisture and soil texture with implication for measured, modeled and remotely sensed estimates, Geophys. Res. Lett., 25, 1757–1760, 1998.
Teuling, A. J. and Troch, P. A.: Improved understanding of soil moisture variability dynamics, Geophys. Res. Lett., 32, {L}05404, https://doi.org/10.1029/2004GL021935, 2005.
Teuling, A. J., Hupet, F., Uilenhoet, R., and Troch, P. A.: Climate variability effects on spatial soil moisture dynamics, Geophys. Res. Lett., 34, l06406, https://doi.org/10.1029/2006GL029080, 2007.
Vereecken, H., Kamai, T., Harter, T., Kasteel, R., Hopmans, J., and Vanderborgth, J.: Explaining soil moisture variability as a function of mean soil moisture: A stochastic unsaturated flow perspective, Geophys. Res. Lett., 34, l22402, https://doi.org/10.1029/2007Gl031813, 2007.
Verhoest, N. E. C., De Baets, B., Mattia, F., Satalino, G., Lucau, C., and Defourny, P.: A possibilistic approach to soil moisture retrieval from ERS synthetic aperture radar backscattering under soil roughness uncertainty, Water Resour. Res., 43, {W}07435, https://doi.org/10.1029/2006WR005295, 2007.
Verhoest, N. E. C., Lievens, H., Wagner, W., \'{Alvarez-Mozos}, J., Moran, M. S., and Mattia, F.: On the soil roughness parameterization problem in soil moisture retrieval of bare surfaces from synthetic aperture radar, Sensors, 8, 4213–4248, https://doi.org/10.3390/s8074213, 2008.
Vernieuwe, H., Verhoest, N. E. C., Lievens, H., and De Baets, B.: Possibilistic soil roughness identification for uncertainty reduction on {SAR}-retrieved soil moisture, IEEE T. Geosci. Remote Sens., 49, 628–638, https://doi.org/10.1109/TGRS.2010.2058577, 2011.
Western, A. W., Grayson, R. B., Blöschl, G., and Wilson, D. J.: Spatial Variability of Soil Moisture and its Implications for Scaling, chap. 8, 119–142, CRC PRESS, 2003.
Wilson, D. J., Western, A. W., Grayson, R. B., Berg, A. A., Lear, M. S., Rodell, M., Famiglietti, J. S., Woods, R. A., and McMahon, T. A.: Spatial distribution of soil mositure over 6 and 30 cm depth, Mahurangi river catchment, {N}ew {Z}ealand, J. Hydrol., 276, 254–274, 2003.
Witten, I. H. and Frank, E.: Data {M}ining: {P}ractical {M}achine {L}earning {T}ools and {T}echniques With {J}ava {I}mplementations, Morgan Kaufmann Publishers, San Francisco, 2005.
Zadeh, L.: The concept of a linguistic variable and its application to approximate reasoning, part i, Inform. Sciences, 8, 199–249, 1975.
Zar, J. H.: Biostatistical {A}nalysis, Prentice-Hall Inc., New Jersey, USA., 1999.