An introduction to Forecast, Errors, Uncertainty in Models, and Forecast Correction

Following the link below, you can find  the presentation I gave at the Pensa Trasversale initiative. I talked about modelling and its uncertainty, and I had, obviously, in mind my experience as a hydro-geomorpho-logical modeler.
The last topic in the title, forecast correction, is not as deep investigated as I would have. But in writing I realised that I had to speak to High School Students.
The presentation is in Italian, but I can translate it in English if someone is interested.  In the case, I should do a further investment in making some parts more technical and add some examples.

The presentation can be found, as usual, on slideshare. A companion of the presentation, also in Italian, of this presentation can be this paper that I wrote more than twenty years ago about modelling, entitled: Introduction to the Mathematical Models of Environment.  I dedicated this small contribution to Sandro Marani with whom I discussed a lot the topic.

Water Scarcity

Water scarcity is a reality for large populations in the World, and several projects started to understand it and to provide solutions.

Also regions where water is usually abundant suffer the threats of climate change and could be subject and conflicts about waters uses.
Today I was informed of the Glowasis blog   where many information are collected on the subject.

Rivers in transitions

An editorial of Nature Geoscience to read.

"Rivers affect landscape structure and function to a much greater extent than might be expected from the fraction of the Earth's surface they cover. Rivers redistribute material as they flow, carving out canyons and building new land offshore. These morphological consequences of river flow are evident in any topographic map of the Earth's surface. ..."

Other links are also available at the page.

Browsing the same number also a commentary is available on the role of rivers, and a paper on river drainage patterns in New Zealand.

Guidelines for the Mapping of the Triggering of Landslides and Debris Flow

My studies on shallow landslides were not purely theoretical but directed to make safer the mountain environment in which I live. Therefore, since the beginning of my activities there was an effort to convert theoretical results into practical tools, which, in turn, helped research. These guidelines written for the Danube Flood Risk Project come with this attitude. The work was also supported by the IRASMOS EU Project and, more recently, from the Trento Province. While reading the guidelines themselves is probably the simplest way to approach the mapping of landslide triggering according to my perspective, I also make public the presentation that I gave last and this year on the subject.

The first presentation is an introduction to the subject of hydrological hazards in mountains areas and the topic of guidelines:



The second contains and comments some applications of the guidelines on catchments in Trentino.



All the operation seen (except for the very recent CI-SLAM model) can be reproduced using the tools in the Spatial Toolbox of uDig or using GEOtop.

References

Beven, K J and Kirkby, M J. 1979, A physically based variable contributing area model of basin hydrology Hydrol. Sci. Bull., 24(1),43-69

Beven, K, Rainfall-runoff modelling: the primer, Wiley, 2001

Borga, M., G. Dalla Fontana, F. Cazorzi, Analysis of topographic and climatic control on rainfall-triggered shallow landsliding using a quasi-dynamic wetness index, Jour. Hydrol., 268, 56-71, 2002
D’Odorico, P. and R. Rigon, Hillslope and channels contribution to the hydrologic response, Water Resour Res, 39(5) , 1-9, 2003

Lanni, C.; McDonnell, J. J.; Rigon, R., On the relative role of upslope and downslope topography for describing water flow path and storage dynamics: a theoretical analysis, Hydrological Processes Volume: 25 Issue: 25 Pages: 3909-3923, DEC 15 2011, DOI: 10.1002/hyp.8263

Lanni C., J. McDonnell JJ, Hopp L., Rigon R., "Simulated effect of soil depth and bedrock topography on near-surface hydrologic response and slope stability" in EARTH SURFACE PROCESSES AND LANDFORMS, v. 2012, (In press). - URL: http://onlinelibrary.wiley.com/doi/10.1002/esp.3267/abstract . - DOI: 10.1002/esp.3267

Lanni C., Borga M., Rigon R., and Tarolli P., Modelling catchment-scale shallow landslide occurrence by means of a subsurface flow path connectivity index, Hydrol. Earth Syst. Sci. Discuss., 9, 4101-4134, www.hydrol-earth-syst-sci- discuss.net/9/4101/2012/ doi:10.5194/hessd-9-4101-2012, (in press at HESS)

Other papers and material about landslides can be found in this blog following the "Landslides" label.

My Past Research on Cryopheric Hydrology

In [J22] it was demonstrated that a single-layer snowpack model can be sufficiently accurate in describing the evolution of the water equivalent of the snow, as long as the incident radiation is calculated accurately taking care of shadows and the complexity of mountain topography.

Subsequently, the single-layer model was replaced with a multilayer model in order to forecast the evolution of density and of metamorphism of the snow as well as the percolation phenomena within the snowpack, during the thesis of Stefano Endrizzi. Among the various studies carried out, one validates the snow model satellite data derived from MODIS [A41].  Furthermore, the same model was used to study the hydrological evolution of glaciers in Trentino (Alpine) and South America (Equatorial) [A39, A47].  Eventually, the modeling of the cryosphere moved towards considering evolutive processes of permafrost [thesis of Matteo Dall'Amico, and J30], that is the layer of soil subject to temperatures below zero centigrades for more than two consecutive years.  All of these research projects, as well as allowing the aforementioned studies, are necessary to modeling the entire yearly hydrological cycle in mountain environments such as Trentino.

[J30], drawing from an accurate work of reanalysis of process thermodynamics, implements a robust method for the integration of the freezing-soil equation.  The numeric algorithm used is globally convergent Newtonian method that is appropriate for the equations under study.  [J36] is a geomorphological survey of rock glaciers in Trentino, to be subsequently modelled with GEOtop.

References in English


[ J22] - Zanotti, F., Endrizzi, S, Bertoldi, G. e R. Rigon, The GEOTOP snow module, Hydrol. Proc., 18, 3667-3679 (2004), DOI 10.1002/hyp.5794

[j30]- M. Dall’Amico, S. Endrizzi, S. Gruber, and R. Rigon, An energy-conserving model of freezing variably-saturated soil, The Cryosphere, 5, 469-484, 2011, doi:10.5194/tc-5-469-2011

[J36] - R. Seppi, A. Carton, M. Zumiani, M. Dall’Amico, G. Zampedri, R. Rigon, "Inventory, distribution and topographic features of rock glaciers in the southern region of the Eastern Italian Alps (Trentino)" in Geografia Fisica e Dinamica Quaternaria, v. 2012, n. 35(2) (In press)

[A41] Endrizzi S., Bertoldi G., Neteler M., and Rigon R., Snow Cover Patterns and Evolution at Basin Scale: GEOtop Model Simulations and Remote Sensing Observations, Proceedings of the 63th Eastern Snow Conference,


References in Italian

[A47] Noldin I., Endrizzi S., Rigon R., Dall’Amico M, Sistema di drenaggio di un ghiacciaio alpino, Neve e Valanghe, n. 69, 48-52, 2010

My Past Research on Physico-Statistical Modelling of the Water Cycle at Basin Scale

While GEOtop [J24, J25] is for process-based modelling of the mass and energy budgets at a small scale, in order to model larger catchments, which include abstraction works or hydraulic structures, it was decided to implement a new modelling system JGrass-NewAGE [J34].  This system sacrifices process details in favour of  efficient calculations.  It is made of components apt at returning statistical hydrological quantities, opportunely averaged in time and space.  One of the goals of this implementation effort was to create the basis for a physico-statistical hydrology in which the hydrological spatially distributed dynamics is reduced into low dimensional components, when necessary surrogating the internal heterogeneities with "suitable noise" and a probabilistic description.

Unlike other efforts of synthesis, JGrass-NewAge wants to keep the spatial description explicit, at various degrees of simplicity.  This has been made possible by opportune processing of distributed information which, in this way, has become part of the model itself.
From the point of view of the information technology used to implement the modelling  [J41, A44, A49, A50], the system is based on the OMS v 3 system, which allows the use of modern, object-oriented strategies for the structuring of the deployment of the software and, at the same time, furnishing not a model, but various, interchangeable, modeling solutions (MS) that can be adapted to the problems in hand and the practical demands of the problem being solved.
The modeling system, as well as the components to model the physical processes themselves, also includes various tools for the processing of input data (for example, Kriging tools), including all the tools of the Horton Machine [eb3] for the processing of digital terrain data, and the tools for the treatment and interpretation of the output data, for the calibration of model parameters, and (in perspective) for continuous data assimilation.
With this in mind, an effort that is currently being made is that of creating an opportune digital watershed scheme that can accommodate the needs of the various modeling conceptualizations and the identification of areas that are hydrologically "similar" that can be treated conjointly during the calculation of flows and storage. At the moment, model solutions use standard implementations.  [J34, J41, A50] contains the description of the rainfall-runoff part of the modelling system; [J43] is a verification of the radiation budgets components; [J44] is an example of simplified snow modelling.  As a standard, any components is verified by itself against the data relative to the process that it describes, using various automatic calibration procedures, and quantitative objective functions. [J34, J41] using the infrastructure show how increased geomorphological (and processes) information affects the quality of reproduction of the hydrologic response. [j44] explains the watershed partition, based on a generalisation of the Pfafstetter numbering scheme, that guide the functioning of the JGrass-NewAGE system.

References 

In English:

[J24] - Rigon R., Bertoldi G e T. M. Over, GEOtop: A distributed hydrological model with coupled water and energy budgets, Vol. 7, No. 3, pages 371-388

[J25] Bertoldi G. R. Rigon e T. M. Over, Impact of watershed geomorphic char- acteristics on the energy and water budgets, Vol. 7, No. 3, pages 389-394, 2006

[J34] - Formetta, G.; Mantilla, R.; Franceschi, S., Antonello A., Rigon R., The JGrass- NewAge system for forecasting and managing the hydrological budgets at the basin scale: models of flow generation and propagation/routing, Geoscientific Model Development Volume: 4 Issue: 4 Pages: 943-955, DOI: 10.5194/gmd-4- 943-201, 2011

[A49] Formetta G., Antonello A., Franceschi S., David O. and Rigon R., The informatics of the hydrological modelling system JGrass-NewAge, 2012 International Congress on Environmental Modelling and Software Managing Resources of a Limited Planet, Sixth Biennial Meeting, Leipzig, Germany R. Seppelt, A.A. Voinov, S. Lange, D. Bankamp (Eds.) http://www.iemss.org/society/index.php/iemss- 2012-proceedings, 2012

[j36] - Formetta G., Rigon R., Chavez J.L., David O., The short wave radiation model in JGrass-NewAge System, Geosci. Model Dev., 6, 915-928, 2013, www.geosci-model-dev.net/6/915/2013/
doi:10.5194/gmd-6-915-2013

[J39] - Formetta G., Antonello A., Franceschi S., David O., and Rigon R., Hydrological modelling with components: A GIS-based open-source framework, Environmental Modelling & Software, 5 (2014), 190-200

[j42] - Formetta G., David O., Kampf S., Rigon R., The Cache la Poudre river basin snow water equivalent modeling with NewAge-JGrass, accepted GMD, 2014

[j44] Formetta G. , Antonello A. , Franceschi S. , David O., Rigon R.,  Digital watershed representation within the NewAge-JGrass system. Boletin Geologico y Minero, 125 (3): 371-381, 2014. ISSN: 0366-0176

In Italian:

[A44] Antonello A., Franceschi S., Formetta G., Rigon R., L’infrastruttura NewAGE per la previsione e la gestione dei bilanci idrici a scala di bacino: I - La struttura informatica, in Atti XXXII Convegno di Idraulica e Costruzioni Idrauliche, Palermo, 14-17 Settembre 2010

[A45] Formetta G., Franceschi S., Antonello A., Cordano E., Mantilla R., Rigon R., Il sistema NewAGE per la previsione e la gestione dei bilanci idrici a scala di bacino. II - I modelli di generazione, aggregazione e propagazione del deflusso. in Atti XXXII Convegno di Idraulica e Costruzioni Idrauliche, Palermo, 14-17 Settembre 2010

[A50] Formetta G., Rigon R, Le nuove componenti modellistiche di JGrass-NewAGE, Atti del XXXIII Convegno di Idraulica e costruzioni Idrauliche, Brescia, 10-15 settembre 2012

My Past Research on Shallow Landslide and Mass Flow Triggering

The role of hydrology in triggering mass movements was initially confronted with an implementation of the theories of Montgomery and Dietrich [1994] (MD), and the case of instability caused by surface runoff [A21, A26, A27].  The study then continued with the analysis of transient phenomena, that is the instabilities caused by the propagation of pressure waves in the unsaturated medium  [A31, A32], according to the theory by Iverson [2000] (I), and integrating  the two, MD1994 and I2000, views even in the case of rainfall of varying intensity [A21, J23].
Then, the simplified approach  (important in as so much as it highlighted some qualitative aspects of infiltration in the hillslopes) was supplanted by the use of the GEOtop model for the continual simulation of hydrological variables [A38, J26], and transient effects, within a minimal set of simplifications.  The use of GEOtop has allowed for the separation of the hydrological part, effectively modeled by GEOtop, and the geotechnical part, contained in the GEOtop-FS model [J26].  Particularly, the latter of these was the subject of a probabilistic treatment that introduced uncertainties into the main geotechnical parameters  [J26].
The paper [J26], and the thesis of Silvia Simoni introduced a systematic approach to the identification of areas of instability that made full use of the potential of on-site geophysical measurement campaigns and the a priori characterization of geotechnical properties of the soil in the laboratory, without using back analyses for the calibration of parameters as is generally done by simplified models.  The IRASMOS Reports [rep06, rep07 and rep08] represent a summary of the literature available on this subject which has been eventually refined in [rep09].

The most recent work  has been focused on trying to understand the dynamics of subsurface flow  in  by means of virtual experiments [A43] with GEOtop, and in more conceptualized terms to explicit the role of the variability of depth of soil [J33, J35, thesis of Cristiano Lanni]  with the model denominated CI-SLAM.  The result is the introduction of the concept of "hydrological connectivity" of the hillslopes, which is realized when a perched water table forms that covers the whole basin.  The connectivity concept bridged the gap between hillslope hydrology and basin hydrology, and has also consequences important for hillslopes' stability [J37]. In fact these concepts allows a better statistical identification of landslide areas, than previous similar models.  [J35] also contains a preliminary attempt to use the theories of self-organizing criticality in the context of instability propagation, which, evidently, heralds the actual landslide itself.

Paper [J46] faces the issues related to the choice of a certain parameterisation of the soil retention curves and analyses their relation to hillslope stability. It uses a new theory that uses double porosity, and estimates the stability with the use of the new theories by Lu, Likos and Godt.

References

In English:

[ J23] - D’Odorico, P., Fagherazzi G., Rigon R. Potential for landsliding: Dependenceon hyetograph characteristics J. Geophys. Res., Vol. 110, No. F1, F01007 10.1029/2004JF000127 10 February 2005

[J26] Simoni, S., F. Zanotti, G. Bertoldi and R. Rigon, Modelling the probability ofoccurrence of shallow landslides and channelized debris flows using GEOtop-FS, Hydrol. Process. 22, 532–545, 2008, DOI: 10.1002/hyp.6886

[J33] - Lanni, C.; McDonnell, J. J.; Rigon, R., On the relative role of upslope anddownslope topography for describing water flow path and storage dynamics:a theoretical analysis, Hydrological Processes Volume: 25 Issue: 25 Pages: 3909-3923, DEC 15 2011, DOI: 10.1002/hyp.8263

[J35] - Lanni C., J. McDonnell JJ, Hopp L., Rigon R., "Simulated effect of soil depthand bedrock topography on near-surface hydrologic response and slope stability" in EARTH SURFACE PROCESSES AND LANDFORMS, v. 2012, (In press). - URL: http://onlinelibrary.wiley.com/doi/10.1002/esp.3267/abstract . - DOI: 10.1002/esp.3267

[J37] Lanni C., Borga M., Rigon R., and Tarolli P., Modelling catchment-scale shallowlandslide occurrence by means of a subsurface flow path connectivity index, Hydrol. Earth Syst. Sci. Discuss., 9, 4101-4134, (in press at HESS)

[A31] - E. Cordano, P., Bartolini, Rigon R. A flexible numerical approach to solving a generalized Richards’ equation problem and some applications, 2004

[rep06]- Rigon R., Rickenmann D., Catalogue of causes and triggering thresholds (Ed), IRASMOS EU Project Deliverable 1.1, 2007

[rep07] - Rigon R. (Ed), State-of-the-art models: their transferability and model application, IRASMOS EU ProjectDeliverable 1.2, 2007

[rep08] - R. Rigon, State of the art of prediction techniques, IRASMOS EU Project Deliverable 1.3, 2007

[rep09] - R.Rigon, Franceschi, S., Monacelli, G., and Formetta, G., The triggering of landslides and debris flows and their mapping, Danube Flood Risk EU Project, 2012

[J46] - Ciervo F. ,  Casini F. , Papa M.N. ,  Rigon R., Some remarks on bimodality effects of the hydraulic properties on shear strength of unsaturated soils, Vadose Zone Hydrology, published electronically, doi:10.2136/vzj2014.10.0152, 2015

In Italian:

[A21] - D’Odorico, P., Fagherazzi S., Rigon R. Frane superficiali e idrologia deiversanti: Un possibile metodo di indagine. Atti del XXVIII Convegno di Idraulica e Costruzioni Idrauliche, vol. V, pp.177-184, 2002

[A26] - Tiso, C., Bertoldi G. and R. Rigon. Il modello Geotop-SF per la determinazione dell’nnesco di fenomeni di franamento e di colata. Atti del Convegno Iterpraevent 2004, Riva del Garda, 24-28 Maggio 2004

[A27] - Rigon, R., A. Cozzini, S. Pisoni, G. Bertoldi e A. Armanini. A new simple method for the determination of the triggering of debris flows. Atti del Convegno Interpraevent 2004, Riva del Garda, 24-28 Maggio 2004

[A32] - Cordano, E., Panciera R., Rigon R., Bartolini P. Sulla soluzione diffusiva dell’equazione di Richards. Atti del XXIX Convegno di Idraulica e Costruzioni Idrauliche, Settembre 2004

[A43] Lanni C., Cordano E., Rigon R., Tarantino A., Analysis of the effect of normaland lateral subsurface water flow on the triggering of shallow landslides witha distributed hydrological model. in from geomorphology mapping to dynamic modelling, Strasbourg: CERG, 2009. Atti di: A Tribute to Prof. Dr. Theo van ASCH, Strasbourg, 6th-7th February 2009