Uncertainty assessment in projection of the extreme river flows, the case of Ömerli catchment, İstanbul

Download
index.pdf
2015
Engin, Batuhan Eren
Show full item record
226
views
90
downloads
The average temperature at the surface of the Earth has been increasing over the past century due to the increased greenhouse gases concentrations in atmosphere through anthropogenic activities. Rising temperature leads to an increase in evaporation and thus intensifies the components of water cycle which results in extreme flows in different parts of the world through changes in globally averaged precipitation. Projection of extreme flows is very important in this aspect, yet obscurity about many factors that would influence future climate causes great uncertainty in climate variable prediction. Therefore, in this research, it is intended to quantify relative contribution to the uncertainty in extreme flow (high and low) projection change for the future period by two factors, the parameterization of a hydrological model and temperature and precipitation inputs from fifteen different Regional Climate Models (RCM), for Omerli Catchment area, in Istanbul. The uncertainty due to the precipitation and temperature inputs is investigated by using 15 different RCMs and also by applying two different statistical downscaling (SD) methods to the RCMs outputs for the vi reference (1961-1990) and future (2071-2099) period, “Bias Correction in Mean” and “Change Factor”. The uncertainty due to the hydrological parameterization (HP) of the hydrological model is assessed by using 25 different parameter sets generated by Monte-Carlo simulation technique using 5 different Nash functions as the objective function during the calibration of the hydrological model, which are NSE_Normal, NSE_BL, NSE_p3, NSE_Viney and NSE_Weighted. Observed daily precipitation and temperature records are provided by Turkish State Meteorological Service for the period 1961-2004, while daily discharges are obtained from State Hydraulic Works for the period 1978-2004. In converting the precipitation and temperature from RCMs into discharges, the HBV Hydrological model is used, which is calibrated to the period 1978-1985 and validated for the period 1986-2004. Main finding is that the relative contribution to the uncertainty by the temperature and precipitation inputs from different regional climate models is greater than the uncertainty caused by hydrological model parameterization in prediction of extreme high flow events in each data type: Original RCM, BC and CF methods. BC and CF increase the total mean variance in the changes in extreme high flow and low events from reference to future period. It is found that the observed dominant high flow events mostly occur during autumn/winter season for the reference period. Simulations using Original RCM, BC and CF data overestimate the seasonality index for the reference period. For the future period, simulations by parameter files using BC and CF data projected that the seasonality in high flow events will be stronger than their reference period, which means that in the future the Omerli catchment would likely to observe more dominant high flow events in autumn/winter.
Floods., Streamflow., Climatic changes., Hydraulic measurements.
http://etd.lib.metu.edu.tr/upload/12618526/index.pdf
https://hdl.handle.net/11511/24453
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Ocean acidification research in the Mediterranean Sea: Status, trends and next steps
Hassoun, Abed El Rahman; Bantelman, Ashley; Canu, Donata; Comeau, Steeve; Galdies, Charles; Gattuso, Jean-Pierre; Giani, Michele; Grelaud, Michael; Hendriks, Iris Eline; IBELLO, VALERİA; Idrissi, Mohammed; Krasakopoulou, Evangelia; Shaltout, Nayrah; Solidoro, Cosimo; Swarzenski, Peter W. W.; Ziveri, Patrizia (2022-09-01)
Ocean acidification (OA) is a serious consequence of climate change with complex organism-to-ecosystem effects that have been observed through field observations but are mainly derived from experimental studies. Although OA trends and the resulting biological impacts are likely exacerbated in the semi-enclosed and highly populated Mediterranean Sea, some fundamental knowledge gaps still exist. These gaps are at tributed to both the uneven capacity for OA research that exists between Mediterranean countries,...
Syntheses of benzotriazole based conjugated polymers for organic light emitting diode and organic solar cell
Önk, İpek; Çırpan, Ali; Arslan Udum, Yasemin; Department of Polymer Science and Technology (2016)
Nowadays, people are on the edge of huge energy problem since the concentrations of greenhouse gases are dramatically increased and it causes the greenhouse effect that lead to warming of the Earth. In order to lessen the effect, OLED devices gain importance since they help to decrease the energy consumption because of its low driving voltage. Therefore, the discovery of OLED ushered a new epoch for flat panel displays and solid state lighting. The most powerful candidate of green energy source is the solar...
CO2 hydrogenation to methanol over supported copper and gallium based catalysts at the atmospheric pressure
Osmanağa, Sezer; İpek Torun, Bahar; Önal, Işık; Department of Chemical Engineering (2022-8)
The continuous increase of the CO2 concentration in the atmosphere has been negatively impacting the environment, due to its contribution in the global warming. Hence, it is necessary for the current CO2 valorization techniques to advance in order to make use of CO2. A possible technique is the CO2 hydrogenation to methanol and DME. The process of CO2 hydrogenation to methanol has been taking place in industry for about a century. However, due to the thermodynamic limitation imposed by the reaction stoichio...
Comparison of BEST and LEED green building rating systems through cost based optimization
Uğurlu, Bengisu; Aksoy, Ayşegül; Department of Environmental Engineering (2020-1-25)
Buildings have significant effects on climate change due to vast resource consumption and pollution generation. Improving the effective use of limited resources and constructing environmentally friendly buildings are important in the realm of mitigations for climate change. Several countries have their green building rating systems tailored towards their regulations, distinctive climatic conditions, unique cultures and traditions, diverse building types and ages, or wide-ranging environmental, economic, and...
Modelling of carbon sink capacity of the Black Sea
Cengiz, Yelis; Yılmaz, Ayşen; Yücel, İsmail; Department of Earth System Science (2016)
The concentration of carbon dioxide in the atmosphere is constantly increasing due to human activities and results in global warming. Since Industrial Revolution 30 and 25 percentages of the anthropogenic atmospheric carbon dioxide are taken up by the forests and by the oceans respectively. Carbon dioxide is rising faster than biosphere can tolerate and the rest of the carbon dioxide which can not be hold, continues to accumulate and causes further heating of the atmosphere. The carbon sink capacity of the ...
Citation Formats
B. E. Engin, “Uncertainty assessment in projection of the extreme river flows, the case of Ömerli catchment, İstanbul,” M.S. - Master of Science, Middle East Technical University, 2015.
METU IIS - Integrated Information Service open@metu.edu.tr