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
Ristna 1950-2011 Tallinn 1899-1995 Narva 1899-2011 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 4 5 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
60 Sea level (cm) level Sea 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
60 Sea level (cm) level Sea 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 (S-N) component v a 40
] model measurement u -1 u 20
0
-20 current velocity [cm s s [cm velocity current -40 0 5 10 15 20 25 30 35 40 b 40 time [days, from 13.06.2011]
] model measurement -1 20 v
0
-20 current velocity [cm s s [cm velocity current -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 2 0.375 0.0125 2 3401000 20 U gh U H 0.283 tanh 0.53 tanh 320 40 s 2 0.375 100 g U gh tanh 0.53 2 300 10 60 U 280 1 80 0.25 0,1 gF 0.375 0.077 260 100 U gh U 2 T 2.4 tanh 0.833 tanh s 2 0.375 g U gh 240 120 tanh 0.833 2 U 220 140 200 160 gT 2 2h 180 S Ls tanh 2 LS Fetches in different locations
100 120 80
x 60 2-20 100 150
1-10 250 x Hs sõltuvus fetsist (a), sügavusest (b) 150 a 3.5 5 256 km b 100 m 3 128 km 50 m 64 km 4 2.5 32 km 20 m 2 16 km 3 8 km 10 m 1.5 4 km 2
1 2 km 5 m
wave height [m] height wave wave height [m] waveheight 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 wind speed [m s -1] wind speed [m s-1] Measured waves (and winds) near Harilaid RDCP, in 2006/07
. 3 d Hs = 3.2 m, max 4.6 m, 5-6 m
2
1
Signif. wave height (m) waveheightSignif. 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 24 Time (days, from 20.12.06)
) d W storm 14-15.01.2007; 23 m/s, gusts 33 m/s -1 18
12
6 Wind speed (m s (m speedWind 0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Dets. Jaan. TimeVeeb. (days, from Märts 20.12.06) 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 2.4 measurement Vilsandi- Harilaid 1.6 calibration: wave height [m] height wave 0.8 5 months in 2006/07
0 (r=0.88, RMSE=0.23 m) 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 model: av=0.50, max=2.86 2 Letipea ps.-Kunda: r = 0.923 RMSE = 0.223 m calibration 40 d in 2006 st.RMSE = 7.8% 1 Verification 30 d in 2008 wave height [m] height wave (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 Harilaid C Matsi-Kihnu E Letipea 0.7 0.6 1 0.5 5 0.6 0.5
0.4
Hs, m Hs, m Hs, Hs, m Hs, 0.5 0.4
0.3 0.4 0.3 2 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 Harilaid (99) D Matsi-Kihnu (99) F Letipea (99) 1 5 3 2.2 1.8
2.5
Hs, m Hs, Hs, m Hs, Hs, m Hs, 2 1.8 1.4 1.5 2 1.4 1 1 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 1965 1975 1985 1995 2005 Year Year Year 14 Tallinn Sea level variations
20
A Tallinn (1.8/0.1)
cm ,
0 Sea level Sea
-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 60 Narva-Jõesuu (0.5+1.4)
Local sea level trends 40 depend on local uplift rate Pärnu 20 (1.5+0.7)
Corrected with uplift: 0 Virtsu (1.8+0.1) 10
- Narva cm (b) - Pärnu , -20 Heltermaa - Tallinn
. (2.4+0.2) 0 - Ristna Sea level Sea -40 Rohuküla (2.4+0.1)
Ristna -10 -60
Sea level (cm) levelSea (cm) (2.6-1.1)
Paldiski* -80 (2.6/-0.5) -20 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Time (year) -100 1890 1910 1930 1950 1970 1990 2010 Year Sea level rises in winter (climate change manifest in
60 winter conditions: Pärnu sea level 1924-2008: + 25 cm I, II, III (winter) temp., storminess) 30
0 Sea level (cm) level Sea -30 300 D Pärnu 1923-2011, range 400 cm y = 0.29x - 575 -60 150 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 60 Year Pärnu sea level 1924-2008: VII, VIII, IX (summer) + 2 cm 0 30 level,cm Sea
0 -150 J F M A M J J A S O N D
Sea level (cm) level Sea Month -30 y = 0.02x - 30
-60 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Maxima 250 Pärnu 1923-2005 a=120.5 b=27.2 Trends in maxima are Narva 1899-2004 200 a=108.2 b=23.5 increasing fast Ristna 1950-2002 a=85.9 b=20.3 150 (4-6 mm/yr) Tallinn 1899-1995 a=76.3 b=14.1
Return periods and values 100 Annual sea level maxima (cm) . level sea Annual 50 1 10 100 1000 Return period (yr)
250 Pärnu (trend slope 2.0 mm/y, land uplift 1.5 mm/yr) 300 e Ruhnu*1.1 wind;
200 250 Max Ventspils 275 level cm on cm
, 200 9 JanuaryObserved 2005 150 Modelled (E) 150
Sea levelSea (cm) 100
Sea level Sea 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 a) 7 Upvelling along the straight idatuul sections of coast, when wind 0
blows persistently along the coast W-E wind comp. (m/s) (m/s) wind comp. W-E Summer 2006 case, Gulf of Finland -7 0 5 10 15 20 25 30 35 Time (days from 10.08.2006) o 11.07.06 “normaalne” 20-22 C b) 30stratifitseeritud hoovus
0
-30
Velocity(cm/s) 2-4 m layer 7-9 m layer -60 0 5 10 15 20 25 30 35 Time (days from 10.08.2006) o 07.08.06 Eesti rannikul 4-10 C a) 18 madal T, kõrge S 7.8
14 6.8
C) o RDCP 10 Salinity 5.8
Temperature Salinity
6 4.8 Temperature ( Temperature 2 3.8 0 5 10 15 20 25 30 3520 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 Influence on coasts Harilaiu Ps. – Kiipsaare and Kelba Capes
Kiipsaare
Kelba RDCP 3 a) 27 Nov. O 6 Dec. O
Kelba spit during storm 2
Berit (27-29. Nov. 2011) 1 Sea level, m level, Sea 0 Sea level (smooth) Sea level + model wave height -1 0 5 10 15 20 25 Days from 12.11.2011
1 km Osmussaar and Neugrund - 540 mill.year old meteorite crater 7-8 km diameter, current height 50 m buried over different periods of time, re-exposed
RDCP Osmussaar Neugrund
RDCP Sundgrund
25 Natural history - after the last ice age Osmussaar emerged from the Baltic Sea about 3000 years ago
Ancylus Lake 8000 years ago Littorina Sea 5000-7000 years ago
The present rate of the postglacial rebound ~2.7 mm/year 26 Tide gauge data 1950-2011: annual means annual max 20 a Paldiski (2.6) d Paldiski 100
Local mean sea levels 0 still slightly decrease 50 because the uplift (cm) level Sea 2.4...2.7 mm/yr is a bit -20 0 1950 1970 1990 2010 1950 1970 1990 2010 20 faster than the global Year 200 Year sea level rise (1.9 b Rohuküla (2.4) e Rohuküla mm/yr in 1950-2011, 150 but probably 3 mm/yr 0 100 in last 10 years)
Sea level (cm) level Sea 50
-20 0 1950 1970 1990 2010 1950 1970 1990 2010 However, trends in 20 Year 200 Year annual max sea levels c Ristna (2.6) f Ristna significantly increase: 150
more storms and 0 100 coastal erosion
50 Sea level (cm) level Sea
-20 0 27 1950 1970 1990 2010 1950 1970 1990 2010 Year Year Exposed W and N coasts: coastal erosion 1954, 35m high Cliff recedes ~9 cm/year The lighthouse several times rebuilt (1765, 1850, 1954)
• fetches for waves are longer • SW-W-NW: direction for prevailing winds and storms
28 The eroded sediment (gravel, pebble) moves alongshore, southward, especially during storms
Beach ridges (up to 2-3m high) and spits are formed; “new land”
Osmussaar as a whole slowly migrates to SE
29 Coastal developments at the two southern study sites
• Coastline on the SW and S parts is migrating seaward by formation of accumulative beach ridges and spits of gravel, pebble and sand. • The accumulative spit (in OS) has grown about 800 m since 1900; a previous bay (Inahamne) became a lake in ~1935