University of Tartu, The oldest and largest in Estonia Founded in 1632 by King Gustavus Adolphus of Sweden 18 000 students www.ut.ee Faculty of Science and Technology Includes Estonian Marine Institute www.sea.ee 1
Estonian Marine Institute, University of Tartu (locates in Tallinn) Dep. of marine systems about 10 employees head: Dr. Robert Aps a number of applied and EU projects Scientific research theme (2008-2013) head Dr. Ülo Suursaar The main task: Climate change induced decadal variations in hydrodynamic conditions and their influence on benthic habitats and coasts of the Estonian coastal sea 2
Tallinn Tartu 3
Material and methods: Physical geography & oceanography • Sea level and wind forcing data 1950-2011 (by EMHI) • Hydrodynamic measurements with RDCP at Neugrund and Sundgrund, etc. 2006-12: waves, currents, sea level, T, S, O2, turbidity • Hydrodynamic modelling of currents and sea level • Wave hindcast (reconstruction) based on measured (1966-2011) EMHI wind data; • Coastal geomorphic studies in co-operation with Tallinn Univ. o in situ surveys, GPS measurements in 2004-2011 o Dynamics of shorelines based on maps and ortophotos from 1900, 1935, 1939, 1947, 1961, 1981, 1998, 2005, 2008, 2010 o Analysis of erosion/ sedimentation volumes using MapInfo
Material and methods : wind and sea level Wind and sea level data – both for forcing and statistics Narva 1899-2011 Ristna 1950-2011 Tallinn 1899-1995 Kunda 1950-2011 Vilsandi 1948-2011 Pärnu 1924-2011
Material and methods: deployment of hydrodynamic measuring equipment 3 MHz ADP (Sontek) 600 KHz RDCP (AADI Aanderaa)
Material and methods: hydrodynamics Study of hydrodynamics using RDCP-600 (by AADI Aanderaa) Wave parameters (also for wave model calibration), currents, T, S, sea level, turbidity: ~900 days 2 3 6 1 5 4
Material and methods: sea level, currents Shallow sea 2D hydrodynamic model (Suursaar & Kullas, 2006); 1 km grid step; forced by Vilsandi wind data and open boundary (Ristna tide gauge) sea level - Verifications (below) - control run (realistic data) - scenario runs with modified forcings 180 (a) Rohuküla mod+60: AV=0.8, SD=24; meas: AV=1.8, SD=22 (cm) r=0.94 120 Sea level (cm) 60 0 -60 0 90 180 270 360 180 (b) Pärnu mod+60: AV=2.1, SD=28; meas: AV=3.2, SD=26 (cm) r=0.90 120 Sea level (cm) 60 0 -60 0 90 180 270 360
Hydrodynamic modelling Validation of the 2D model results regarding currents, measured using RDCP at Matsil in June- July 2011 u (W-E directed) and v v (S-N) component a u 40 u model measurement -1 ] current velocity [cm s 20 0 -20 -40 0 5 10 15 20 25 30 35 40 b 40 model measurement v -1 ] current velocity [cm s 20 0 -20 -40 0 5 10 15 20 25 30 35 40 5 cm/sec time [days, from 13.06.2011]
Material and methods: wave hindast Wave hindcast using the SMB (Sverdrup-Munk-Bretschneider) type model (Seymour 1977; USACE 2002) Calculates significant wave (Hs) parameters for the specific fetch-depth-limited location Forced by wind speed, also depends on depth and fetch (calculated from wind direction as headwind distance to the shore) Fetch is the length of water over which a given wind has blown, each point has its own specific angular distribution of fetches: 0 . 42 gF 0 0 . 0125 1000 340 20 0 . 375 2 2 U gh U H s 0 . 283 tanh 0 . 53 tanh 320 40 100 2 0 . 375 g U gh tanh 0 . 53 300 10 60 2 U 1 280 80 0,1 0 . 25 gF 0 . 077 260 100 0 . 375 2 U gh U T s 2 . 4 tanh 0 . 833 tanh 2 0 . 375 g U gh 240 120 tanh 0 . 833 2 U 220 140 200 160 2 gT 2 h 180 S L tanh s 2 L S
Fetches in different locations 100 120 80 x 60 2-20 100 150 1-10 x 250 Hs sõltuvus fetsist (a), sügavusest (b) 150 a 3.5 5 256 km 100 m b 3 128 km 50 m 4 wave height [m] 64 km wave height [m] 2.5 32 km 20 m 3 2 16 km 10 m 8 km 1.5 2 4 km 5 m 2 km 1 1 km 1 0.5 2 m 0 0 11 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 -1 ] wind speed [m s -1 ] wind speed [m s
Measured waves (and winds) near Harilaid RDCP, in 2006/07 3 Signif. wave height (m) . Hs = 3.2 m, max 4.6 m, 5-6 m d 2 1 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 24 Time (days, from 20.12.06) W storm 14-15.01.2007; 23 m/s, gusts 33 m/s d Wind speed (m s -1 ) 18 12 6 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Dets. Jaan. Veeb. Märts Aprill Mai
Material and methods: wave hindast • Calibration of the SMB wave model against RDCP measurements at the two locations – very good results • Calibrated model used in 1966-2010 hindcast (w. 3 h step), so if we have extended our RDCP measurements back to 1966 3.2 model wave height [m] 2.4 Vilsandi- Harilaid measurement calibration: 1.6 5 months in 2006/07 0.8 (r=0.88, RMSE=0.23 m) 0 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 time [days, from 20.12.2006] 3 a measurement: av=0.50, max=2.91 Letipea ps.-Kunda: model: av=0.50, max=2.86 wave height [m] 2 calibration 40 d in 2006 r = 0.923 RMSE = 0.223 m Verification 30 d in 2008 st.RMSE = 7.8% 1 (r=0.92, RMSE=0.22 m) 0 0 5 10 15 20 25 30 35 40 time [days, from 16.10.2006]
Wave hindcasts 1966-2011 (with 1h/ 3h interval) - Average (Hs) probably decreased - High events (max, 99%) probably increased on westerly exposed coasts decreased on N and E exposed coasts 0.8 0.6 0.7 A C E Matsi-Kihnu Harilaid 1 Letipea 5 0.7 0.6 0.5 0.6 0.5 Hs, m Hs, m Hs, m 0.4 0.5 0.4 0.3 2 0.4 0.3 0.3 0.2 0.2 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 2.6 2.2 3.5 Year Year Year B D F Letipea (99) 1 Harilaid (99) 5 Matsi-Kihnu (99) 3 2.2 1.8 2.5 Hs, m Hs, m Hs, m 2 1.8 1.4 2 1.5 1.4 1 1 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 14 Year Year Year
Tallinn Sea level variations 20 A Tallinn (1.8/0.1) Sea level, cm 0 -20 1840 1860 1880 1900 1920 1940 1960 1980 2000 Longest series in Estonia, 1842 – 1995 Trend 0,1 mm/a Post-glacial Fennoscandian uplift up to 8 mm/a, in Estonia 0,5-2,5 mm/a, in Tallinn ~1,8 mm/a, Thus, sea level rise 0,1+1,8 = 1,9 mm/a
Sea level, other locations B Narva- Jõesuu 60 (0.5+1.4) Local sea level trends 40 depend on local uplift rate Pärnu 20 (1.5+0.7) Corrected with uplift: Virtsu 0 (1.8+0.1) 10 Sea level, cm - Narva (b) -20 - Pärnu Heltermaa - Tallinn (2.4+0.2) . Sea level (cm) - Ristna 0 -40 Rohuküla (2.4+0.1) Ristna -10 -60 (2.6-1.1) Paldiski* (2.6/-0.5) -80 -20 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 -100 Time (year) 1890 1910 1930 1950 1970 1990 2010 Year
Sea level rises in winter (climate change manifest in winter conditions: 60 temp., storminess) Pärnu sea level 1924-2008: + 25 cm I, II, III (winter) 30 Sea level (cm) 0 300 D -30 Pärnu 1923 -2011, range 400 cm y = 0.29x - 575 -60 Sea level, cm 150 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 60 Year Pärnu sea level 1924-2008: + 2 cm VII, VIII, IX (summer) 0 30 Sea level (cm) 0 -150 J F M A M J J A S O N D Month -30 y = 0.02x - 30 -60 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year
Maxima Annual sea level maxima (cm) . 250 Pärnu 1923-2005 Trends in maxima are a=120.5 b=27.2 Narva 1899-2004 increasing fast 200 a=108.2 b=23.5 Ristna 1950-2002 (4-6 mm/yr) a=85.9 b=20.3 150 Tallinn 1899-1995 a=76.3 b=14.1 Return periods and values 100 50 1 10 100 1000 Return period (yr) 250 Pärnu (trend slope 2.0 mm/y, 300 land uplift 1.5 mm/yr) e Ruhnu*1.1 wind; Max 275 cm on Sea level, cm 200 250 Ventspils level 9 January 2005 Sea level (cm) 200 Observed 150 Modelled (E) 150 100 100 50 50 0 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 0 2 4 6 8 10 12 Year Days (January 2005)
Pärnu, Gudrun in Jan. 2005 up to 273 cm storm surge
Upvelling along the straight a) 7 W-E wind comp. (m/s) idatuul sections of coast, when wind 0 blows persistently along the coast Summer 2006 case, Gulf of Finland -7 0 5 10 15 20 25 30 35 Time (days from 10.08.2006) o C stratifitseeritud hoovus 11.07.06 “normaalne” 20 -22 b) 30 Velocity (cm/s) 0 -30 2-4 m layer 7-9 m layer -60 0 5 10 15 20 25 30 35 Time (days from 10.08.2006) 07.08.06 Eesti rannikul 4-10 o C madal T, kõrge S 18 7.8 a) 14 6.8 o C) RDCP Temperature ( Salinity Salinity 10 5.8 Temperature 6 4.8 2 3.8 20 0 5 10 15 20 25 30 35 Time (days from 10.08.2006)
Coastal studies (with ÖI, Tallinn University) Coastal studies with GPS at Harilaid, Osmussaar (2004-2012) Old maps, photos, GIS 21
Painted sediment experiment Osmussaar Sept. 2011 22
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