Apr 10, 2016

Cloud Cover on the surface net radiation

Solar radiation is the key  driving force for water cycle. It modulates how much water land surface evaporates and plant transpires. The  explicitly estimation of  radiation is essential for water budget modelling. One of the major factor affect the net surface radiation is the cloud cover. It can affect the net radiation in many ways.  The influence of cloud on the land surface energy depends on several factors, such as cloud altitude, it size, the nature of the cloud particles.

Due to the lack of accurate cloud cover information, the  net radiation modelling thereby the processes of  land-atmosphere interaction is poorly characterised. Some spatial cloud cover data, as given by recent satellite imagery, however, can contribute for better estimation of the basin water budget simulation.  For effort in this direction, EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF) cloud cover fraction data can be useful resource. Here I have processed this data for Upper Blue Nile basin to be used in water budget modelling. A sample of the monthly mean could cover map over the basin for the 1994 is shows in figure 1.

The seasonality of the cover can be clearly seen, and this contributes to the reason for  governing factors of  the seasonality in the basin  water budget.  

Some papers on cloud and hydrology 

Cawkwell, F. G. L., and J. L. Bamber. "The impact of cloud cover on the net radiation budget of the Greenland ice sheet." Annals of Glaciology 34.1 (2002): 141-149.

Alados, I., et al. "Relationship between net radiation and solar radiation for semi-arid shrub-land." Agricultural and Forest Meteorology 116.3 (2003): 221-227.

Frank Richards and Phil Arkin , 2009: On the Relationship between Satellite-Observed Cloud Cover and Precipitation. Monthly Weather Review109, 1081–1093, doi: 10.1175/1520-0493(1981)109<1081:OTRBSO>2.0.CO;2.

J. A. Griggs and J. L. Bamber , 2010: Assessment of Cloud Cover Characteristics in Satellite Datasets and Reanalysis Products for Greenland. Journal of Climate21, 1837–1849, doi: 10.1175/2007JCLI1570.1.

to be updated….

Apr 2, 2016

PhD thesis is submitted….

Last week I submitted my PhD thesis, and my final defense is schedule on April 28, 2016. Th title of thesis is "Modelling water budget at a basin scale using JGrass-NewAge system".  It contains about eight chapters, where the first and the last chapters are the introduction and the concluding synthesis of the issues being discussed. I will take time, after the defense, to summarise  the results of the research. Here, instead I would like to pass my gratitude to all individuals who helped me through the last four years. The acknowledgement of the thesis is given as follows:

Here I am at the end of my PhD journey. To pass the ups and downs of life in general and the PhD journey in particular, there has been many people helping me directly and indirectly. Before and above all, GOD is always my mainstay.

First and foremost I would like to thank my supervisor, Professor Riccardo Rigon, for all his ideas, discussions, support, criticism, and thorough review of my works. His technical skills to solve problems at hand and long term envision and outlook for the subject of hydrology is exceptional. I also would like to thank him for demanding better research results; for challenging my decisions; and for providing me funds to cover part of my PhD studies and attend conferences, seminars and summer schools. These supports, both the financial and intellectual, contributes to my academic growth as a hydrologist. Prof, thank you for all! 

I am indebted to Professor Marco Borga of Padova University for his support by providing me data, having comments and discussion on my works. He was also my MSc thesis supervisor, and the first person to introduce me to the subject of hydrology.

My colleague and friend Dr. Giuseppe Formetta helped me a lot with the source codes and practicalities of JGrass-NewAge model system. The success of this PhD work is also comes from his immense support in the codes and informatics point of view. Thanks Giuseppe!. I am sincerely thankful to my research group members, Marialaura Bancheri and Francesco Serafin. 

I would like to extend my heartfelt gratitude to Dr. Luca Brocca (Research Institute for Geo-Hydrological Protection, National Research Council, Italy) for his support for providing me data, for the discussion we have and the corrections he made on my work.

I am grateful to National Meteorological Agency (NMA) of Ethiopia, Ministry ofWater Resources (MOWR) of Ethiopia, and University of Reading for providing me meteorological, discharge and TAMSAT satellite rainfall data for Upper Blue Nile basin respectively.

I would like to extend my gratitude to all academic and administrative staffs of the Department of Civil, Environmental, and Mechanical Engineering of Trento university. The Department of Geography and Environmental studies of Mekelle University is always kind to me, and thankful for granting me a study leave. 

I would like to thank my father, Abera Worku, and my mother, Taytu Mohamed, who grew me up in the best possible way they can. I am who I am now is because they nurtured and educated me all the way. Mommy and Daddy, you are the source of my happiness. I wish you long live! 

Most importantly, I would like to thank my wife, Muluadam Teshome for her love and support. Her encouragement, love and care during difficult time has been my source of strength. I love you so much, sweetheart!

Finally, to all my friend, you know who you are, and others who I have not mentioned, but who have helped, contributed, encouraged or even discouraged, I tried to learn something from you as much as I can. Thank you!

This work is dedicated to the farmers of Ethiopia who suffers from recurrent deadly droughts and poor water resource governance.