Understanding and monitoring coupled heat and mass transfer in field-soils is relevant in many processes in which **evaporation dynamics** is crucial: soil-atmosphere interaction, groundwater recharge, vegetation growth. We investigate the role played by evaporation on soil-moisture dynamics to ameliorate the parametric models that describe **field-soil response to diurnal forcing**.

Our activity combines experiments, theory and modeling. Our theoretical analysis focuses on the practical effects of employing sparse data to estimate water and energy balance [2]. Our experiments concentrate on assessing the capability of different measurement techniques to monitor vadose-zone processes, and in particular the simultaneous transfer of moisture, heat and solutes. Our current research in this field focuses on the use of **optical fibers** [1] to measure both temperature and soil moisture (in the latter case the fiber is heated and the classical probe method is applied to infer thermal conductivity and water content). We also test **Multi Functional Heat Pulse Probe** and compare their performance with classical methods based on dielectric measurements [Ciocca, Sharma, Lunati, Parlange, 2013 –in preparation].

(a) | (b) |

Figure: (a) Comparison between soil moisture measured by traditional dielectric probes (green) and by the Heated Optical Fiber method using two different inversion procedures (red and blue) [1]. (b) Illustration of the Multi Function Heat Pulse Probe (MFHPP) that we are currently employing to measure thermal gradient in soils.

**References**

[1] Ciocca, F., I. Lunati, N. van de Giesen, and M.B. Parlange, Heated Optical Fiber for Distributed Soil-Moisture Measurements: A Lysimeter Experiment, *Vadose Zone Journal*, 11(4), 2012 doi:10.2136/vzj2011.0199 [pdf]

[2] Lunati, I., F. Ciocca, and M.B. Parlange, On the use of spatially discrete data to compute energy and mass balance, *Water Resources Research*, 48, W05542, 2012, doi:10.1029/2012WR012061

[3] Ciocca, F., I. Lunati, and M.B. Parlange, Effects of the water-retention curve on evaporation from dry soils, *Geophysical Research Letters*, 41(9), 3110–3116, 2014 doi:10.1002/2014GL059827

[4] Ciocca, F., *Moisture and energy dynamics in fields soils: the influence of the diurnal cycle*, PhD thesis, EPFL, 2013 [text]