Ph.D student at LMV/Chalmers

Topic : Gravimetry (AG, SG) Student : Per-Anders OlssonSupervisor : Hans-Georg Scherneck

(Jonas Ågren)Where? : LMV/ChalmersFinanced by: LMVWhen? : 2007-09-01 2013-12-31??

First project – Baltic Sea

Paper to Jena 2008-09-01

Why Baltic Sea?

• Large amplitude

• Not periodic

• Not handled (FG5)

• Data ”avaliable”

• Unique conditions

• Short and long term effects

Theoretical approach

1. Farrell, W.E., 1972. Deformation of the Earth by Surface Loads, Reviews of Geophysics and Space Physics, 10, 761-797.

2. Jentzsch, G., 1997. Earth Tides and Ocean Tidal Loading. in Tidal Phenomena, pp. 145-172, eds. Wilhelm, H., Zürn, W. & Wenzel, H.-G. Springer-Verlag, Berlin Heidelberg.

seasurface

g dAHGg )()(

Spherical, elastic earth

Greens function for gravity

Convolution of Greens function and sea surface

Newtonian effect at height

Load love numbers from• G-B Earth Model1• PREM reference earth model2

Some examples

…the purpose of the following is not to present any results (everything is

still preliminary), I just want to give You an idea of what

I am working with and hopefully get some response to that.

Please, be aware…

Stations and grid

10 degree sea surface Baltic sea surface

One meter water (1)

Station Newton Loading Total Newton Loading Total

Arjeplog 1.79 3.97 5.76 0.29 0.69 0.98

Kiruna 1.86 4.11 5.97 0.24 0.50 0.74

Kramfors 2.40 3.99 6.39 1.59 2.38 3.97

Kungsholmsfort 7.13 4.89 12.02 6.61 3.70 10.31

Mårtsbo 1.37 3.88 5.25 0.69 2.55 3.24

Onsala 1.82 5.11 6.93 0.39 1.09 1.48

Skellefteå 1.64 3.89 5.53 0.67 1.98 2.66

Smögen 5.47 5.34 10.81 0.37 0.93 1.29

Visby 1.56 5.04 6.59 1.11 4.16 5.27

Östersund 1.71 3.78 5.48 0.38 0.99 1.37

Ratan 1.72 4.24 5.96 0.87 2.59 3.46

Lycksele 1.48 3.42 4.90 0.42 1.25 1.67

LMV 1.42 3.98 5.40 0.65 2.49 3.14

Metsähovi 0.92 2.95 3.87 0.68 2.53 3.22

10 degree sea surface Baltic sea surface

All numbers in gal

One meter water (2)

Distribution of the loading effect

Data from SMHI (1)

Stn_name

Sealevel [cm]

2008-03-06

2008-03-27

Kalix 78 -60

Furuogrund 80 -50

Ratan 75 -42

Spikarna 70 -20

Forsmark 60 -12

Stockholm 65 10

Landsort_Norra 57 20

Marviken 45 12

Oskarshamn 30 30

Kungsholmsfort -10 40

Simrishamn -30 40

Skanor -60 45

Klagshamn -55 40

Barseback 0 30

Ringhals 30 15

Goteborg 35 5

Smogen 35 0

Kungsvik 35 0

Data from SMHI (2)

2008-03-06 2008-03-27

Data from SMHI (3)

Stationg [gal]

2008-03-06 2008-03-27

Arjeplog 0.73 -0.25

Kiruna 0.77 -0.20

Kramfors 2.65 -0.82

Kungsholmsfort -0.34 3.70

Mårtsbo 1.86 -0.19

Onsala 0.91 0.54

Skellefteå 1.92 -0.96

Smögen 2.29 0.25

Visby 2.01 0.95

Östersund 0.89 -0.19

Ratan 2.43 -1.10

Lycksele 1.13 -0.40

LMV 1.78 -0.19

Metsähovi 1.70 -0.29

Sensitivity of location (1)

text

H/10 < Thetacritical < H*10

One meter water, 10 degree sea surface

StationDistance from

coast [m]Height (RH2000)

[m]Direct attraction

[gal]

Direct attractionH = 0

[gal]

Diff[gal]

Arjeplog 156000 450 1.79 1.76 0.03

Kiruna 154000 466 1.86 1.83 0.03

Kramfors 1120 120 2.40 1.39 1.01

Kungsholmsfort

10 2 7.13 1.295.84

Mårtsbo 7380 44 1.37 1.32 0.05

Onsala 170 6 1.82 1.54 0.28

Skellefteå 1360 55 1.64 1.46 0.18

Smögen 20 6 5.47 1.65 3.82

Visby 2770 46 1.56 1.34 0.22

Östersund 150000 453 1.71 1.67 0.04

Ratan 2200 53 1.72 1.45 0.27

Lycksele 113400 245 1.48 1.46 0.02

LMV 2720 14 1.42 1.40 0.02

Metsähovi 16400 56 0.92 0.88 0.04

Sensitivity of location (2)

Long term sea level change

Station Delta_g [gal/year]

Arjeplog -0.0087

Kramfors -0.0351

Kungsholmsfort -0.0137

Mårtsbo -0.0217

Onsala -0.0107

Skellefteå -0.0250

Smögen -0.0267

Visby -0.0164

Östersund -0.0110

Ratan -0.0318

Lycksele -0.0142

LMV -0.0208

Metsähovi -0.0148

Storm in the Baltic Sea 1872

Station Newton Loading Total

Gedser 55.3332 4.8397 60.17

Kungsholmsfort 8.3527 3.1339 11.49

Onsala -0.4211 -1.1027 -1.52

Smogen -3.4792 -1.5830 -5.06

Visby 0.0919 0.4216 0.51

Sea level in Danish foot (0.3 m)

All numbers in gal

Conclusions...

To come…

… Baltic loading

… Groundwater

… Atmospheric loading

… GIA

… SG/AG