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Impact of climate change on the Curonian Lagoon water balance components, salinity and water temperature in the 21st century

Jakimavičius D., Kriaučiūnienė J., Šarauskienė D.

Oceanologia

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2018

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No. 60 (3)

378--389

EN

The Curonian Lagoon is a shallow water body connected to the Baltic Sea by a narrow navigable strait, which enables an exchange of water of different salinity. The projected climate change together with the peculiarities of mixing water will undoubtedly alter hydrological regime of this lagoon. The study uses three climate model outputs under four RCP scenarios, four sea level rise scenarios and hydrological modelling in order to project the extent to which water balance components, salinity and temperature may change in the future. In order to simulate river inflow, the Nemunas River hydrological model was created using HBV software. In general, the changes of the lagoon water balance components, salinity and temperature are expected to be more significant in 2081-2100 than in 2016-2035. It was estimated that in the reference period (1986-2005) the river inflow was 22.1 km3, inflow from the sea was 6.8 km3, salinity (at Juodkrantė) was 1.2 ppt and average water temperature of the lagoon was 9.2°C. It was projected that in 2081-2100 the river inflow may change from 22.1 km3 (RCP2.6) to 15.9 km3 (RCP8.5), whereas inflow from the sea is expected to vary from 8.5 km3 (RCP2.6) to 11.0 km3 (RCP8.5). The lagoon salinity at Juodkrantė is likely to grow from 1.4 ppt (RCP2.6) to 2.6 ppt (RCP8.5) by the end of the century due to global sea level rise and river inflow decrease. The lagoon water temperature is projected to increase by 2-6°C by the year 2100.

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Assessment of wave climate and energy resources in the Baltic Sea nearshore (Lithuanian territorial water)

Jakimavičius D., Kriaučiūnienė J., Šarauskienė D.

Oceanologia

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2018

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No. 60 (2)

207--218

EN

The main task of the present research was to analyse wave climate and evaluate energy resources in the Lithuanian territorial waters of the Baltic Sea. Wave and wind parameters were analysed according to long-term measurement site data. Distribution of wave parameters in the Baltic Sea Lithuanian nearshore was evaluated according to wave modelling results. Wave energy resources were estimated for three design years (high, median and low wave intensity). The results indicated that in the coastal area of Lithuania, waves approaching from western directions prevail with mean wave height of 0.9 m. These waves are the highest and have the greatest energy potential. The strongest winds and the highest waves are characteristic for the winter and autumn seasons. In the Baltic Sea Lithuanian nearshore, the mean wave height ranges from 0.68 to 0.98 m, while the estimated mean energy flux reaches from 0.69 to 1.90 kW m−1 during a year of different wave intensity. Distribution of energy fluxes was analysed at different isobaths in the nearshore. Moving away from the coast, both wave height and wave power flux increases significantly when water depth increases from 5 to 20 m. Values of the mentioned parameters tend to change only slightly when the sea is deeper than 20 m. In a year of median wave intensity, the mean wave energy flux changes from 1.10 kW m−1 at 10 m isobaths to 1.38 kW m−1 at 30 m isobaths. The identified differences of wave height and energy along the selected isobaths are insignificant.

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Insight into variability of spring and flash flood events in Lithuania

Meilutytė-Lukauskienė D., Akstinas V., Kriaučiūnienė J., Šarauskienė D., Jurgelėnaitė A.

Acta Geophysica

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2017

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Vol. 65, no. 1

89--102

EN

In this research, variability of spring (from 1 March to 30 May) and flash (from 1 June to 30 November) floods in rivers of different regions was analysed. The territory of Lithuania is divided into three regions according to hydrological regime of the rivers: Western, Central, and Southeastern. The maximum river discharge data of spring and flash floods [a total of 31 water gauging stations (WGS)] were analysed. Comparison of the data of four periods (1922–2013, 1941–2013, 1961–2013, and 1991–2013) with the data of the reference period (1961–1990) was performed. Analysis included the longest discharge data set of the Nemunas River at Smalininkai WGS (1812–2013) as well. Mixed patterns of flood changes in Lithuanian rivers were detected. The analysis of flood discharges of the Nemunas River indicated that both spring and flash floods in Lithuania were getting smaller.