1.  Mahalakshmi, D. V., Arati, P., Dutta, D., Ali, M. M., Dadhwal, V. K., Suraj, R. R., Jha, C. S. and Sharma, J. R.: Estimation of net surface radiation using eddy flux tower data over a tropical mangrove forest of Sundarban, West Bengal.

In this study, net surface radiation (Rn) was estimated using artificial neural network (ANN) and Linear Model (LM). Then, estimated Rn with both the models (ANN and LM) were compared with measured Rn from eddy covariance (EC) flux tower. The routinely measured meteorological variables namely air temperature, relative humidity and wind velocity were used as input to the ANN and global solar radiation as input to the LM. All the input data are from the EC flux tower. Sensitivity analysis of ANN with all the meteorological variables is carried out by excluding one by one meteorological variable. The validation results demonstrated that, ANN and LM estimated Rn values were in good agreement with the measured values, with root mean square error (RMSE) varying between 21.63 W/m2 and 34.94 W/m2, mean absolute error (MAE) between 17.93 W/m2 and 22.28 W/m2 and coefficient of residual mass (CRMS) between -0.007 and -0.04 respectively. Further we have computed modelling efficiency (0.97 for ANN and 0.99 for LM) and coefficient of determination (R2 = 0.97 for ANN and 0.99 for LM) for both the models. Even though both the models could predict Rn successfully, ANN was better in terms of minimum number of routinely measured meteorological variables as input. The results of the ANN sensitivity analysis indicated that air temperatuere is the more important parameter followed by relative humidity, wind speed and wind direction.

Keywords: net surface radiation, artificial neural network, linear model, eddy flux tower

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2.  Akkaya, U. and Doğan, E.: Generation of 2D flood inundation maps of Meriç and Tunca Rivers passing through Edirne city center.

Natural disasters can be defined as hazardous and usually large scale natural incidents that may cause loss of lifes and property and that occur mainly or completely out of human control. Due to climatic changes draughts are being experienced in various parts of the world in the recent years. Floods are also observed to take place more frequently and severely in some regions. As it is reported by many scientific studies, flood modeling can only be possible through the designation of flood risk management strategies and the determination of the dynamic behaviors of rivers. In this context, the city of Edirne located downstream of Meriç River Basin, which runs through Turkish, Bulgarian and Greek soils, is frequently exposed to flooding. The majority of the currents that cause this take place within the Bulgarian borders, which covers 66% of the basin. This part of Meriç River Basin has a mountainous geography, it has a rather high average slope of 12.5% within Bulgarian lands, while in Edirne it is quite low with a bottom slope of 0,00036. In the present study, 2D flood modeling of the Meriç and Tunca Rivers that passes through Edirne city center were made and flood inundation maps were generated. With the analysis of the results obtained from flood inundation maps, a drainage channel capable of discharging flood rates that exceed the maximum rate Meriç River main bed can accommodate was designed, and the downstream conditions of the channel were evaluated.

Keywords: flood map, 2D model, MIKE 11 and MIKE 21, Meriç River, discharge channel

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3.  Pasarić, M. and Slaviček, L.: Seiches in the Plitvice Lakes.

A campaign of high-frequency measurements of water level was carried in the two largest of the Plitvice Lakes, Prošće and Kozjak, to study seiches in the lakes. Measurements were performed at 1-min sampling rate during a 46-day interval, at two opposite ends in each lake, which also provided information on the phase relations. Power spectra were calculated to determine the periods of the normal modes. The observed peaks in the spectra were interpreted with the help of theoretical results obtained by the simple numerical method of Defant, where two different historical bathymetries were used. The lake Prošće oscillates at the periods of 8.5 min, 5.0 min, 3.3 min and 2.2 min, the oscillations being related respectively to uni-, bi-, three- and five-nodal seiche modes, whereas the four-nodal mode (2.5-2.7 min) was not significant during the experiment. The lake Kozjak oscillates at 9.0 min, 4.9 min and 2.6 min, which corresponds respectively to the uni-, bi- and four-nodal mode, the five-nodal mode is likely at the period of 1.9 min, while the three-nodal mode (~ 3.4 min) was not generated; the deeper sub-basin displays its own principal mode at the period of 2.3 min. The discrepancy between the observed and the calculated periods is attributed to poor representation of the basin by the historical bathymetries, especially at Prošće, but also to changes in basin depth, due to continuous process of tufa growth.

Keywords: Plitvice, seiches, periods, bathymetry, tufa growth

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4.  Tudor, M. and Janeković, I.: Modelling origin and transport fate of waste materials on the southeastern Adriatic coast (Croatia).

In this study we analysed meteorological and oceanographic conditions that lead to the waste deposition along the southeast Croatian coast during the second half of November 2010. We used available in situ measurements, atmospheric products (reanalysis, remote sensing) as well as atmosphere and ocean numerical models. The measured meteorological data reveal that an intensive rainfall event occurred from 7 till 10 November 2010, over the parts of Montenegro and Albania. It was followed by a substantial increase of the river water levels indicating a possibility of flash floods, capable of splashing the waste material into a river and after to the Adriatic Sea (or to the sea directly). The currents that could bring this waste to Croatian coast are likely intensified by the strong wind from southeast direction. In order to test these two hypotheses we set a number of numerical drifter experiments with trajectories initiated over southeast Adriatic during the intensive rainfall events following their path in space and time. The numerical drifter trajectory experiments that resulted with drifters reaching the right position (southeastern Adriatic coast) at exact time the waste was observed were initiated on 00:00 and 12:00 UTC of 10 November 2010 during the mentioned high precipitation event.

Keywords: Adriatic, drifter trajectory, numerical models, flash flood

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5.  Khodja , M. R., Prange, M. D. and Djikpesse, H. A.: Accounting for seismic radiation anisotropy in Bayesian survey designs

are essentially anisotropic due to its ubiquitous stratified structure. This anisotropy seriously complicates formation imaging and data acquisition. This is most salient for deep-water subsalt reservoirs. Traditionally, point scatterers with isotropic radiation patterns are used in migration imaging, but in the survey design problem, these might lead to design errors caused by receivers being placed in poor locations with respect to the radiation pattern of the scattering structure. Here, we extend a framework which accounts for anisotropy in the scattered radiation for optimal geophysical survey design purposes. The propagation medium is assumed to be attenuative. The locally dipping interfaces are modeled as a discrete set of finite-size planar scattering elements. The general elastodynamic expressions for the sensitivity kernels, i.e., the vectors which mathematically represent the candidate observations, in the presence of the scattering elements are provided. The size of each element controls the width of its radiation pattern, which may in turn be used to characterize the uncertainty on the dip angle, thus complementing the information provided by the model-parameter uncertainties and ultimately leading to better geophysical survey designs.

Keywords: Bayesian optimal experimental design, dipping scatterers, anisotropic radiation, layered media, model covariance matrix

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6.  Zieliński, A., Mazurkiewicz, E. and Łyskowski, M.: GPR mapping of karst formations under a historic building in Szydłów, Poland.

The Mid-Poland Uplands Belt is a vast area characterized by the presence of carbonate and sulphate rocks. In some parts of this region karst forming and developing processes are dynamic in character. The studied area is the terrain around a historic church in a small village of Szydłów. The building is situated on a hill which is formed by Sarmatian detrital limestone undergoing karst processes. At the foot of the hill there is a number of small caves. Characteristic geological structure and land transformations that are present due to the karst processes prompted the authors to conduct a GPR survey. The aim of this study was to verify whether there is a continuation of caves in the area around the monument. An analysis was made to estimate the risk of damaging the historic building due to the ongoing karst processes. The authors obtained good quality results from GPR measurements. The results confirmed the existence of unknown voids and loosening in rock structure. On radargrams, the authors recorded stratum mapping which confirms the existence of gravitational loosening of the rock mass near the cave ceilings and walls. The results prove that the GPR is an appropriate instrument for mapping some of the karst structures and evaluation of the orogen stability.

Keywords: Ground Penetrating Radar (GPR), karst, limestone, cave, Szydłów, Kielce Uplands

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