Showing posts with label Evapotranspiration. Show all posts
Showing posts with label Evapotranspiration. Show all posts

Mar 16, 2017

Paper accepted: Estimating the water budget components and their variability in a Pre-Alpine basin with JGrass-NewAGE

Finally our paper, on the water budget component estimation in the case where there are some in-situ observations  and when the area is dominated by snow, is accepted. Due to the complexities of issues involved and the tools needed, it has been two/three years since I started to work on this paper. When I say complexities, it mean that while the main goal is  one (i.e. water budget closure spatially, lets say each HRU), but the specific objectives are too many, i.e.

1. Comparison various interpolators/or if possible improve some of the approaches used in literature, with the objective to identify a method that provides more accurate rainfall fields.

2. When a basin is dominated by snow, you can not afford to ignore the snow process, and hence, how much of the total precipitation falling in the form of snowfall is really its own line of research. So we had to come up with some means to do this, and that was the second objective of the paper. 

3. The estimation of ET is problematic. In literature people uses the potential ET to estimate discharge, but most studies does not show actual ET. Hydrological studies are dominated by the rainfall-runoff exercise, with the aim to optimise discharge modelling to obtain high agreement with observed discharge.  From my experience, particularly gained from working on this paper, obtaining discharge estimation having good agreement with discharge observation does not require reasonable estimation of either potential ET or actual ET. Hence, modelling rainfall-runoff, without proper characterisation of ET, could not be the art of science in hydrology. so, the third objective is to estimate ET, which is consistent with the other water budget components.

4. Storage is probable the most difficult to estimate/model at basin scale, hence, the other specific objective of the paper is to develop a methodology for estimating storage at basin scale. 

It was started as two papers, but later we decided to compress them into one. This mean that we have to cut out many results and issues. All this processes took time. In anyway, if you are interested, please find the accepted manuscript here.  


Dec 14, 2016

Evapotranspiration

From 7-11 of November, 2016, I attended an international symposium on ecohydrology in Africa. It is the 2nd African international symposium on ecohydrology for water and ecosystem service, and it seems that the symposium has a back from the political officials with the aim to establish an Ecohydrological centre at Addis Ababa. There were many interesting presentations, with different case studies. The list of presentations and the downloadable slides is available at http://ehsymposiumafrica.org/programme-symposium-africa/

My presentation was  on the methods to estimate basin scale evapotranspiration, eventually water budget. Here you can find my slides.



Wuletawu Abera, presentation on basin scale evapotranspiration, at "ecohydrology in Africa" Symposium (photo credit: Professor Zalewski)