Includes Estonian Marine Institute www.sea.ee 1 Estonian Marine - - PowerPoint PPT Presentation

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

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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

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Tallinn Tartu

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.
• in situ surveys, GPS measurements in 2004-2011
• Dynamics of shorelines based on maps and ortophotos from

1900, 1935, 1939, 1947, 1961, 1981, 1998, 2005, 2008, 2010

• Analysis of erosion/ sedimentation volumes using MapInfo

Wind and sea level data – both for forcing and statistics

Tallinn 1899-1995 Pärnu 1924-2011 Narva 1899-2011 Ristna 1950-2011 Vilsandi 1948-2011 Kunda 1950-2011

Material and methods: wind and sea level

Material and methods:

deployment of hydrodynamic measuring equipment

3 MHz ADP (Sontek) 600 KHz RDCP (AADI Aanderaa)

Study of hydrodynamics using RDCP-600 (by AADI Aanderaa) Wave parameters (also for wave model calibration), currents, T, S, sea level, turbidity: ~900 days

Material and methods: hydrodynamics

1 2 5 4 3 6

• 60

60 120 180 90 180 270 360 Sea level (cm)

(a) Rohuküla mod+60: AV=0.8, SD=24; meas: AV=1.8, SD=22 (cm)

r=0.94

• 60

60 120 180 90 180 270 360 Sea level (cm) (b) Pärnu mod+60: AV=2.1, SD=28; meas: AV=3.2, SD=26 (cm) r=0.90

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

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

Hydrodynamic modelling

5 cm/sec

• 40
• 20

20 40 5 10 15 20 25 30 35 40 current velocity [cm s

• 1]

model measurement

a

• 40
• 20

20 40 5 10 15 20 25 30 35 40 time [days, from 13.06.2011] current velocity [cm s

• 1]

model measurement

b

u v u v

• 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:

Material and methods: wave hindast

                                                 

375 . 2 42 . 2 375 . 2 2

53 . tanh 0125 . tanh 53 . tanh 283 . U gh U gF U gh g U H s                                                  

375 . 2 25 . 2 375 . 2

833 . tanh 077 . tanh 833 . tanh 4 . 2 U gh U gF U gh g U Ts 

        

S S s

L h gT L   2 tanh 2

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0,1 1 10 100 1000 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340

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x x

250 100 150 150 60 1-10 100 80 2-20 120

0.5 1 1.5 2 2.5 3 3.5 5 10 15 20 25 30 35 wind speed [m s

• 1]

wave height [m]

256 km 128 km 64 km 32 km 16 km 8 km 4 km 2 km 1 km

a

1 2 3 4 5 5 10 15 20 25 30 35 wind speed [m s-1] wave height [m]

100 m 50 m 20 m 10 m 5 m 2 m

b

Hs sõltuvus fetsist (a), sügavusest (b)

Fetches in different locations

RDCP, in 2006/07

1 2 3 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Time (days, from 20.12.06)

• Signif. wave height (m)

.

d

• Dets. Jaan. Veeb. Märts Aprill Mai

Hs = 3.2 m, max 4.6 m, 5-6 m

6 12 18 24 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Wind speed (m s-1)

d

W storm 14-15.01.2007; 23 m/s, gusts 33 m/s

Measured waves (and winds) near Harilaid

Vilsandi- Harilaid calibration: 5 months in 2006/07

(r=0.88, RMSE=0.23 m)

Letipea ps.-Kunda:

calibration 40 d in 2006 Verification 30 d in 2008 (r=0.92, RMSE=0.22 m)

1 2 3 5 10 15 20 25 30 35 40 time [days, from 16.10.2006]

wave height [m]

measurement: av=0.50, max=2.91 model: av=0.50, max=2.86 r = 0.923 RMSE = 0.223 m st.RMSE = 7.8%

a

0.8 1.6 2.4 3.2 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] wave height [m] model measurement

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

• Average (Hs) probably decreased
• High events (max, 99%) probably increased on westerly exposed coasts

decreased on N and E exposed coasts

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0.3 0.4 0.5 0.6 0.7 0.8 1965 1975 1985 1995 2005 Year Hs, m Harilaid

A

1.4 1.8 2.2 2.6 1965 1975 1985 1995 2005 Year Hs, m Harilaid (99)

B

0.2 0.3 0.4 0.5 0.6 0.7 1965 1975 1985 1995 2005 Year Hs, m Letipea

E

1 1.5 2 2.5 3 3.5 1965 1975 1985 1995 2005 Year Hs, m Letipea (99)

F

0.2 0.3 0.4 0.5 0.6 1965 1975 1985 1995 2005 Year Hs, m Matsi-Kihnu

C

1 1.4 1.8 2.2 1965 1975 1985 1995 2005 Year Hs, m Matsi-Kihnu (99)

D

1 2 1 5 5 2

Wave hindcasts 1966-2011 (with 1h/ 3h interval)

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

Tallinn Sea level variations

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20 1840 1860 1880 1900 1920 1940 1960 1980 2000

Sea level, cm

Tallinn (1.8/0.1)

A

Local sea level trends depend on local uplift rate Corrected with uplift:

Sea level, other locations

• 100
• 80
• 60
• 40
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20 40 60 1890 1910 1930 1950 1970 1990 2010

Sea level, cm Year

Heltermaa (2.4+0.2) Rohuküla (2.4+0.1) Ristna (2.6-1.1) Paldiski* (2.6/-0.5) Narva-Jõesuu (0.5+1.4) Pärnu (1.5+0.7) Virtsu (1.8+0.1)

B

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• 10

10 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Time (year) Sea level (cm) .

• Narva
• Pärnu
• Tallinn
• Ristna

(b)

y = 0.29x - 575

• 60
• 30

30 60

1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Year Sea level (cm)

Pärnu sea level 1924-2008: I, II, III (winter)

+ 25 cm

y = 0.02x - 30

• 60
• 30

30 60 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year Sea level (cm)

Pärnu sea level 1924-2008: VII, VIII, IX (summer)

+ 2 cm

Sea level rises in winter (climate change manifest in winter conditions: temp., storminess)

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150 300

J F M A M J J A S O N D

Sea level, cm Month

Pärnu 1923-2011, range 400 cm

D

50 100 150 200 250 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Sea level, cm

Year Pärnu (trend slope 2.0 mm/y, land uplift 1.5 mm/yr)

Trends in maxima are increasing fast (4-6 mm/yr) Return periods and values

50 100 150 200 250 300 2 4 6 8 10 12 Days (January 2005) Sea level (cm)

Observed Modelled (E)

e Ruhnu*1.1 wind;

Ventspils level

Max 275 cm on 9 January 2005

Maxima

50 100 150 200 250 1 10 100 1000 Return period (yr) Annual sea level maxima (cm) .

Pärnu 1923-2005 a=120.5 b=27.2 Narva 1899-2004 a=108.2 b=23.5 Ristna 1950-2002 a=85.9 b=20.3 Tallinn 1899-1995 a=76.3 b=14.1

Pärnu, Gudrun in Jan. 2005 up to 273 cm storm surge

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11.07.06 “normaalne” 20-22

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07.08.06 Eesti rannikul 4-10oC

RDCP

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7 5 10 15 20 25 30 35 Time (days from 10.08.2006) W-E wind comp. (m/s)

a)

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• 30

30 5 10 15 20 25 30 35 Time (days from 10.08.2006) Velocity (cm/s) 2-4 m layer 7-9 m layer

b)

2 6 10 14 18 5 10 15 20 25 30 35 Time (days from 10.08.2006) Temperature (

• C)

3.8 4.8 5.8 6.8 7.8 Salinity Salinity Temperature

a)

idatuul stratifitseeritud hoovus madal T, kõrge S

Upvelling along the straight

sections of coast, when wind blows persistently along the coast Summer 2006 case, Gulf of Finland

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Coastal studies with GPS at Harilaid, Osmussaar (2004-2012) Old maps, photos, GIS

Coastal studies (with ÖI, Tallinn University)

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Osmussaar Sept. 2011

Painted sediment experiment

Kelba RDCP Kiipsaare

Influence on coasts

Harilaiu Ps. – Kiipsaare and Kelba Capes

Kelba spit during storm Berit (27-29. Nov. 2011)

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1 2 3 5 10 15 20 25

Sea level, m Sea level (smooth) Sea level + model wave height

O O

27 Nov. 6 Dec.

a)

1 km

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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 Sundgrund RDCP Neugrund Osmussaar

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Natural history - after the last ice age

Osmussaar emerged from the Baltic Sea about 3000 years ago

The present rate

• f the postglacial

rebound ~2.7 mm/year

Ancylus Lake 8000 years ago Littorina Sea 5000-7000 years ago

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Tide gauge data 1950-2011: annual means annual max

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20 1950 1970 1990 2010

Sea level (cm) Paldiski (2.6)

a

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20 1950 1970 1990 2010

Sea level (cm) Rohuküla (2.4)

b

• 20

20 1950 1970 1990 2010 Year

Sea level (cm) Ristna (2.6)

c

50 100 1950 1970 1990 2010

Paldiski

d

50 100 150 200 1950 1970 1990 2010

Rohuküla

e

50 100 150 200 1950 1970 1990 2010 Year

Ristna

f

Local mean sea levels still slightly decrease because the uplift 2.4...2.7 mm/yr is a bit faster than the global sea level rise (1.9 mm/yr in 1950-2011, but probably 3 mm/yr in last 10 years) However, trends in annual max sea levels significantly increase: more storms and coastal erosion

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Exposed W and N coasts: coastal erosion 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

1954, 35m high

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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

• Coastline on the SW and S parts

is migrating seaward by formation

• f 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

Coastal developments at the two southern study sites