University of Tartu, The oldest and largest in Estonia Founded in 163 by King Gustavus Adolphus of Sweden 18 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 1 employees head: Dr. Robert Aps a number of applied and EU projects Scientific research theme (8-13) 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
Tallinn Tartu 3
Material and methods: Physical geography & oceanography Sea level and wind forcing data 195-11 (by EMHI) Hydrodynamic measurements with RDCP at Neugrund and Sundgrund, etc. 6-1: waves, currents, sea level, T, S, O, turbidity Hydrodynamic modelling of currents and sea level Wave hindcast (reconstruction) based on measured (1966-11) EMHI wind data; Coastal geomorphic studies in co-operation with Tallinn Univ. o in situ surveys, GPS measurements in 4-11 o Dynamics of shorelines based on maps and ortophotos from 19, 1935, 1939, 1947, 1961, 1981, 1998, 5, 8, 1 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 195-11 Vilsandi 1948-11 Tallinn 1899-1995 Narva 1899-11 Kunda 195-11 Pärnu 194-11
Material and methods: deployment of hydrodynamic measuring equipment 3 MHz ADP (Sontek) 6 KHz RDCP (AADI Aanderaa)
Material and methods: hydrodynamics Study of hydrodynamics using RDCP-6 (by AADI Aanderaa) Wave parameters (also for wave model calibration), currents, T, S, sea level, turbidity: ~9 days 6 3 1 4 5
Sea level (cm) Sea level (cm) Material and methods: sea level, currents Shallow sea D hydrodynamic model (Suursaar & Kullas, 6); 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 18 1 (a) Rohuküla mod+6: AV=.8, SD=4; meas: AV=1.8, SD= (cm) r=.94 6-6 9 18 7 36 18 1 (b) Pärnu mod+6: AV=.1, SD=8; meas: AV=3., SD=6 (cm) r=.9 6-6 9 18 7 36
current velocity [cm s -1 ] current velocity [cm s -1 ] a Hydrodynamic modelling Validation of the D model results regarding currents, measured using RDCP at Matsil in June- July 11 u (W-E directed) and v (S-N) component v 4 u model measurement u - b -4 4 5 1 15 5 3 35 4 v time [days, from 13.6.11] model measurement - -4 5 1 15 5 3 35 4 time [days, from 13.6.11] 5 cm/sec
Material and methods: wave hindast Wave hindcast using the SMB (Sverdrup-Munk-Bretschneider) type model (Seymour 1977; USACE ) 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: H s T s L U.83 g gh tanh.53 U U gh.4 tanh.833 g U s gt S h tanh LS.375.375 gf.15 U tanh gh tanh.53 U gf.77 U tanh gh tanh.833 U.5.4.375.375 8 6 3 4 1 34 3 1 1 1,1 18 16 4 14 6 8 1 1
wave height [m] wave height [m] Fetches in different locations 15 1 1 8 - x 1 6 5 15 x 1-1 a Hs sõltuvus fetsist (a), sügavusest (b) 3.5 3.5 1.5 1.5 5 1 15 5 3 35 wind speed [m s -1 ] 56 km 18 km 64 km 3 km 16 km 8 km 4 km km 1 km 5 4 3 1 b 11 5 1 15 5 3 35 wind speed [m s -1 ] 1 m 5 m m 1 m 5 m m
Wind speed (m s -1 ) Signif. wave height (m). Measured waves (and winds) near Harilaid RDCP, in 6/7 3 d Hs = 3. m, max 4.6 m, 5-6 m 1 4 18 1 3 4 5 6 7 8 9 1 11 1 13 14 15 d Time (days, from.1.6) W storm 14-15.1.7; 3 m/s, gusts 33 m/s 1 6 1 3 4 5 6 7 8 9 1 11 1 13 14 15 Dets. Jaan. Time Veeb. (days, from Märts.1.6) Aprill Mai
wave height [m] wave height [m] 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 1966-1 hindcast (w. 3 h step), so if we have extended our RDCP measurements back to 1966 3..4 1.6.8 model measurement 1 11 1 13 14 15 16 17 18 19 1 3 4 5 6 7 8 9 3 Vilsandi- Harilaid calibration: 5 months in 6/7 (r=.88, RMSE=.3 m) 3 1 a time [days, from.1.6] measurement: av=.5, max=.91 model: av=.5, max=.86 r =.93 RMSE =.3 m st.rmse = 7.8% Letipea ps.-kunda: calibration 4 d in 6 Verification 3 d in 8 (r=.9, RMSE=. m) 5 1 15 5 3 35 4 time [days, from 16.1.6]
Hs, m Hs, m Hs, m Hs, m Hs, m Hs, m Wave hindcasts 1966-11 (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.8 A.7 1 Harilaid.6.5.4.3 1965 1975 1985 1995 5.6 B Harilaid (99). 1.6 C Matsi-Kihnu.5 5.4.3. 1965 1975 1985 1995 5. D Matsi-Kihnu (99) 1.8 5.7 E.6 Letipea.5.4.3. 1965 1975 1985 1995 5 3.5 F Letipea (99) 3.5 1.8 1.4 1965 1975 1985 1995 5 1.4 1 1965 1975 1985 1995 5 1.5 1 1965 1975 1985 1995 5 14
Sea level, cm Tallinn Sea level variations A Tallinn (1.8/.1) - 184 186 188 19 19 194 196 198 Longest series in Estonia, 184 1995 Trend,1 mm/a Post-glacial Fennoscandian uplift up to 8 mm/a, in Estonia,5-,5 mm/a, in Tallinn ~1,8 mm/a, Thus, sea level rise,1+1,8 = 1,9 mm/a
Sea level (cm). Sea level, cm Sea level, other locations Local sea level trends depend on local uplift rate 6 4 B Narva-Jõesuu (.5+1.4) Pärnu (1.5+.7) Corrected with uplift: 1-1 (b) - Narva - Pärnu - Tallinn - Ristna - -4-6 Virtsu (1.8+.1) Heltermaa (.4+.) Rohuküla (.4+.1) Ristna (.6-1.1) -8-19 191 19 193 194 195 196 197 198 199 Time (year) Paldiski* (.6/-.5) -1 189 191 193 195 197 199 1
Sea level (cm) Sea level, cm Sea level (cm) Sea level rises in winter (climate change manifest in 6 winter conditions: Pärnu sea level 194-8: + 5 cm I, II, III (winter) temp., storminess) 3-3 D 3 Pärnu 193-11, range 4 cm y =.9x - 575-6 19 193 194 195 196 197 198 199 1 6 Pärnu sea level 194-8: VII, VIII, IX (summer) + cm 3 15-15 J F M A M J J A S O N D -3 Month y =.x - 3-6 19 193 194 195 196 197 198 199 1
Sea level, cm Sea level (cm) Annual sea level maxima (cm). Maxima Trends in maxima are increasing fast (4-6 mm/yr) Return periods and values 5 15 1 Pärnu 193-5 a=1.5 b=7. Narva 1899-4 a=18. b=3.5 Ristna 195- a=85.9 b=.3 Tallinn 1899-1995 a=76.3 b=14.1 5 1 1 1 1 Return period (yr) 5 15 Pärnu (trend slope. mm/y, land uplift 1.5 mm/yr) 3 5 15 e Ruhnu*1.1 wind; Max Ventspils 75 level cm on 9 January Observed 5 Modelled (E) 1 1 5 19 193 194 195 196 197 198 199 1 5 4 6 8 1 1 Days (January 5)
Pärnu, Gudrun in Jan. 5 up to 73 cm storm surge
Temperature ( o C) Salinity Velocity (cm/s) W-E wind comp. (m/s) Upvelling along the straight sections of coast, when wind blows persistently along the coast Summer 6 case, Gulf of Finland 11.7.6 normaalne - o C a) b) 7-7 3 idatuul 5 1 15 5 3 35 Time (days from 1.8.6) stratifitseeritud hoovus 7.8.6 Eesti rannikul 4-1 o C a) -3-6 18-4 m layer 7-9 m layer 5 1 15 5 3 35 Time (days from 1.8.6) madal T, kõrge S 7.8 RDCP 14 1 Salinity Temperature 6.8 5.8 6 4.8 3.8 5 1 15 5 3 35 Time (days from 1.8.6)
Coastal studies (with ÖI, Tallinn University) Coastal studies with GPS at Harilaid, Osmussaar (4-1) Old maps, photos, GIS 1
Painted sediment experiment Osmussaar Sept. 11
Influence on coasts Harilaiu Ps. Kiipsaare and Kelba Capes Kiipsaare RDCP Kelba
Sea level, m 3 a) 7 Nov. O 6 Dec. O Kelba spit during storm Berit (7-9. Nov. 11) 1-1 Sea level (smooth) Sea level + model wave height 5 1 15 5 Days f rom 1.11.11 1 km
Osmussaar and Neugrund - 54 mill.year old meteorite crater 7-8 km diameter, current height 5 m buried over different periods of time, re-exposed Osmussaar RDCP Neugrund RDCP Sundgrund 5
Natural history - after the last ice age Osmussaar emerged from the Baltic Sea about 3 years ago Ancylus Lake 8 years ago Littorina Sea 5-7 years ago The present rate of the postglacial rebound ~.7 mm/year 6
Sea level (cm) Sea level (cm) Sea level (cm) Tide gauge data 195-11: annual means annual max a Paldiski (.6) 1 d Paldiski Local mean sea levels still slightly decrease because the uplift.4...7 mm/yr is a bit faster than the global sea level rise (1.9 mm/yr in 195-11, but probably 3 mm/yr in last 1 years) - 195 197 199 1 Rohuküla (.4) b 5 195 197 199 1 Rohuküla 15 1 5 e However, trends in annual max sea levels significantly increase: more storms and coastal erosion - 195 197 199 1 Ristna (.6) c 195 197 199 1 Ristna 15 1 5 f - 195 197 199 1 7 195 197 199 1
Exposed W and N coasts: coastal erosion Cliff recedes ~9 cm/year The lighthouse several times rebuilt (1765, 185, 1954) fetches for waves are longer SW-W-NW: direction for prevailing winds and storms 1954, 35m high 8
The eroded sediment (gravel, pebble) moves alongshore, southward, especially during storms Beach ridges (up to -3m high) and spits are formed; new land Osmussaar as a whole slowly migrates to SE 9
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 8 m since 19; a previous bay (Inahamne) became a lake in ~1935