Thursday, April 27, 2017

New Insights in Permafrost modelling (EGU Wien 2017)

This talk (and work) is another rearrangement of Niccolò Tubini work, and continues Matteo Dall'Amico Ph.D work. It derives the set of equations for water flow in freezing soils based on the same assumptions by Matteo but the results is slightly different at the end. 

Click on the figure above to see the presentation. Hope you enjoy it.

Dalton Prize 2017 to Dani Or

This is the video of Dani Or (GS) lecture for the prize he received at this year EGU Wien. Dani is an outstanding scientist and any of the things he does deserve attention and a reading. He talked about evaporation and others of his lectures were already linked in this blog.

Here below a presentation of Dani.


Here his lecture (unfortunately a little out of focus, but still visible. I hope that there will be an official, professional record from EGU).

Monday, April 10, 2017

Open-source software for simulating hillslope hydrology and stability

This is the material of the SC34/NH10.2 ECS: Open-source software for simulating hillslope hydrology and stability
by Giuseppe Formetta, Francesco Serafin, Riccardo Rigon, Raffaele Albano and Luigi Lombardo (co-conveners)

session of the  2017 EGU meeting in Wien.
For all of this work it is necessary to download a number of softwares.
  • Docker GEOtop,
    • Preliminari to any operation is to install GEOtop 2.0  on your machine. To avoid the complication implied by different platform GEOtop has been compiled against Docker which is a lightweight, well supported mini virtual machine which run on most operating systems.  The instructions on how to do it are available directly at: https://github.com/geotopmodel/docker (scroll down a little the page to see the instructions). Installing Docker is time consuming so, it is essential that participants to the pico session will download it before the session. An alternative little guide is on GrowWorkingHard Other information about the dockerized version of GEOtop can be found here.
    • Other GEOtop information can be found in the GEOtop essential post
  • Next stuff require you to have installed the Java JDK (from Oracle site)
  • Console OMS3, 

Thursday, March 30, 2017

Modelling discharge in an Alpine basin with JGrass-NewAGE

This and a related post reports about the Master thesis by Niccolò Tubini and Stefano Tasin. It was a couple years ago that I graduate my last Master guy, and I am happy with these two graduations.
Stefano thesis is in Italian. So I am summarising it a little bit below.
JGrass-NewAGE has a a snow module that was developed by Giuseppe Formetta (GS). Giuseppe developed also a component called  Adige-Hymod for runoff estimation. The two were not tested conjointly (well, they were), and we would like to have a new case to understand more about the behaviour of the model and sharpen the methods we use with it.
 
Stefano did it, making leverage on the NewAGE database of river Adige and using, side by side with NewAGE, GEOtop as the true to reproduce in matter of snow. Other directions could have taken, but Stefano chose this one with excellent results. He had in mind a relatively small basin in the Norther part of Italy that was known to be dominated by snow (and glacier melt) and he wanted to investigate how much of discharge depends upon snow melting. The figure above is one of his results, which shows an excellent discharge fitting and quite impressive demonstration of how snowmelt counts in this case. Thinking that snow on the Alps is going to almost disappear cause the climate change, the basin will go to a quite large change in the discharge regime. It is foreseeable that winter discharge will grow in place of the summer ones, with possible modifications of the discharges distributions.
The thesis and the simulations files used are here.

Theoretical progress in freezing-thawing processes studies

This and a related post reports about the Master thesis by Niccolò Tubini and Stefano Tasin. It was a couple years ago that I graduate my last Master guy, and I am happy with these two graduations.
Niccolò thesis is about modelling permafrost.

I already worked on it during the Ph.D. thesis by Matteo Dall'Amico, obtaining interesting results, which were published in this 2011 paper. From it we built. Initially the idea was that the work by Matteo dall’Amico was clear enough to go directly to a full three-dimensional implementation of 3D algorithms on a unstructured grid. That was actually not the case an we had to rework all the theory. I do not want to waste its reading. So, if you want to know the story, please click here

The presentation Niccolò gave for his Master (Laurea) degree is here.

Wednesday, March 29, 2017

A field trip to Posina catchment

Since a couple of years we started to work on modelling Posina catchment in the Italian pre-alpine area. There University of Padua colleagues, Marco Borga heading the group, started hydrological measurements since many years. Posina is a small catchment (116 km$^{2}$) located in the Alpine foothills of the Veneto Region in Italy. The elevation difference of the basin is 1820 meters. The climate is characterised as wet, with annual precipitation of 1,645 mm and annual runoff of 1000 mm. For a detailed report on its hydrological budget please see Abera's et al. paper.
Finally we had the occasion to visit it with Marco Borga himself and Giulia Zuecco on March 22 afternoon. Please here below find a photographic synthesis with  some comment.

1 - The position of the gauge station at the Stancari outlet.
2 - A view of the position of Bazzoni gauge position.
3 - A view of the Ressi sub-catchment top with a few of the buckets
4 -A more panoramic view (was not a sunny day)
5 - A panorama view with Giulia, Marco and Marialaura from left to right.
6 - Going inside the catchment, to explore these channels (?) or hollow. Soil depth is not very large here. Many trees just did not succeeded to stay still due to the limited roots development. Here and there the bedrock outcrops, but in other position, especially in the concave parts, soil seems to be deeper. 
7 - Here the bedrock channel is visible. We can see also the soil section with the roots of the tree in the foreground.
8 - The V-shaped weir where discharge and water level is measured
9 - The water sampler to do isotopes estimations
10 - A view of the sampler - weir area from below. Please observe the big fallen tree that just slightly touched the box with the sampler when falling. 
11- The throughfall measurement site. 500 hundred buckets for 500 hundred square meters
12 - The stemflow measurements 
It was a nice a pleasant trip! We hope to continue the collaboration further. 

Thursday, March 16, 2017

Extreme Rainfall Distribution Estimation with Python (as a scripting language)

This post collects the Notebook used in my classes of Hydraulic Constructions and Hydrology for estimating the IDF curves. It is actually a work in progress.

For who wants to start with Python (for hydrologists), I suggest to give a look to my blog post "Python for Hydrologists". Here a brief summary, for the laziest.

There are a lot of resources to start with python, but for hydrologists, a recommendation is to use:
with a preference for the first one (keeping in mind differences between Python 2 and Python 3).
 Soil Physics with Python: Transport in the Soil-Plant-Atmosphere System, by Bittelli et al, is al, is a book on soil science which is quite appealing (as seen the TOC): the kindle version cost reasonably but I do not have it. Python programs are available here.

An overview of Scientific libraries and softwares of general use in Python is given at scipy.org, from which I extract these links to documentation:


3 - Estimating the parameters of a Gumbel distribution with

5 - Fitting the curves (some error here)

Data:

Paperopoli 2
Paperopoli 4

For who wants to do the same numerics with R, she should look "A few R scripts useful for hydrologists".