TY  - GEN
TI  - Time-Series Projection of Surface-Measured Quantities into Depth
AV  - public
ID  - heidok14152
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/14152/
Y1  - 2012///
N2  - This thesis deals with projection methods of soil temperature and soil moisture into depth by a forward model based on near-surface time-series. In addition, thermal as well as hydraulic soil parameters are estimated by using the Levenberg-Marquardt algorithm.
For soil temperature, two analytical projection methods are compared which use the transfer function and the Fourier transform approach, respectively. In each case, additional mathematical strategies are required to improve the projection results, e. g. by adding an integral over the initial profile or applying the Tukey window on the time-series. The resulting projected temperature matches field measurements very well, especially for the transfer function method a residuum down to ±0.05 ?C is achieved. Further, the uniqueness of the parameter space is evaluated and the temporal evolution of the thermal diffusivity is estimated through both projection methods.
The projection of near-surface soil moisture is realized numerically by a finite volume scheme due to the strong non-linearity of the system. On the basis of synthetic data the conditions are explored under which accurate estimations of the hydraulic parameters are feasible. One of these conditions is found to be that the water content range should be larger than 0.5 times of the porosity. The corresponding relative parameter error is found to be some 10?5. Furthermore, the study shows that an accurate estimation is more feasible for soils with a lower saturated conductivity, and steep functions of the hydraulic properties. This is typically the case for soils with a higher sand content. Data from a field site is then used to verify the findings of the synthetic study and to discuss limitations, e.g. ponding water at a soil layer
interface.
A1  - Niederle, Ulrike Angela
ER  -