University of Tartu, The oldest and largest in Founded in 1632 by King Gustavus Adolphus of 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 1899-2011 Kunda 1950-2011 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  2h  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 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- 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 - 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 *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 -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, (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 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