The estimation of evaporative fluxes and their effects on soil suction is assuming a prominent role in the field of interpretation and early-warning prediction of rainfall-induced landslides. Evaporation models refer essentially to sands or plastic (silty and clayey) soils. Models validated specifically for non-plastic silty pyroclastic soils, usually characterized by very high porosity, are instead unavailable. This deficit arises although silty pyroclastic covers are widely spread across the world, increasingly involved in rainfall-induced landslides and recognized showing particular hydrological behaviour. A number of questions may be raised about the issue: (i) may any evaporative models be reliably extended to silty pyroclastic soils?; (ii) what atmospheric variables need to be monitored at least to reliably predict evaporation fluxes in these soils?; and (iii) how accurate evaporation estimations are if they are referred to silty pyroclastic covers for early warning purposes? This study addresses these questions by assessing the capabilities of several simplified models in estimating evaporative (potential and actual) fluxes for silty pyroclastic soils. To this aim, a large-scale lysimeter, consisting in a silty pyroclastic layer exposed to the atmosphere and comprehensively monitored for both weather forcing and hydrological soil variables, is adopted. It provides a dataset of observations suitable to calibrate and validate the selected evaporation models. Moreover, the availability of weather observations makes it possible to define the minimum set of equipment required to attain reliable evaporation estimation. This study shows that: (i) the adoption of a literature-based calibration can produce misleading estimates of actual evaporation, whereas the model performances after a lysimeter-based recalibration are satisfactory; (ii) reducing the weather measurements can induce an overestimation of predicted fluxes up to 50%; and (iii) the investigated models quite accurately predict water out-coming fluxes while running in early warning predictions.

Estimating actual and potential bare soil evaporation from silty pyroclastic soils: Towards improved landslide prediction / Rianna, G.; Reder, A.; Pagano, L. - In: JOURNAL OF HYDROLOGY. - ISSN 0022-1694. - 562:(2018), pp. 193-209. [10.1016/j.jhydrol.2018.05.005]

Estimating actual and potential bare soil evaporation from silty pyroclastic soils: Towards improved landslide prediction

Pagano L
2018

Abstract

The estimation of evaporative fluxes and their effects on soil suction is assuming a prominent role in the field of interpretation and early-warning prediction of rainfall-induced landslides. Evaporation models refer essentially to sands or plastic (silty and clayey) soils. Models validated specifically for non-plastic silty pyroclastic soils, usually characterized by very high porosity, are instead unavailable. This deficit arises although silty pyroclastic covers are widely spread across the world, increasingly involved in rainfall-induced landslides and recognized showing particular hydrological behaviour. A number of questions may be raised about the issue: (i) may any evaporative models be reliably extended to silty pyroclastic soils?; (ii) what atmospheric variables need to be monitored at least to reliably predict evaporation fluxes in these soils?; and (iii) how accurate evaporation estimations are if they are referred to silty pyroclastic covers for early warning purposes? This study addresses these questions by assessing the capabilities of several simplified models in estimating evaporative (potential and actual) fluxes for silty pyroclastic soils. To this aim, a large-scale lysimeter, consisting in a silty pyroclastic layer exposed to the atmosphere and comprehensively monitored for both weather forcing and hydrological soil variables, is adopted. It provides a dataset of observations suitable to calibrate and validate the selected evaporation models. Moreover, the availability of weather observations makes it possible to define the minimum set of equipment required to attain reliable evaporation estimation. This study shows that: (i) the adoption of a literature-based calibration can produce misleading estimates of actual evaporation, whereas the model performances after a lysimeter-based recalibration are satisfactory; (ii) reducing the weather measurements can induce an overestimation of predicted fluxes up to 50%; and (iii) the investigated models quite accurately predict water out-coming fluxes while running in early warning predictions.
2018
Estimating actual and potential bare soil evaporation from silty pyroclastic soils: Towards improved landslide prediction / Rianna, G.; Reder, A.; Pagano, L. - In: JOURNAL OF HYDROLOGY. - ISSN 0022-1694. - 562:(2018), pp. 193-209. [10.1016/j.jhydrol.2018.05.005]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/726938
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