Decadal variability of mass and mass transport in the Mediterranean and relation to climate change

L. Fenoglio1, A. Mariotti5, G. Sannino6, B. Meyssignac7, R. Rietbroek2,, E. Forootan2, S. Grayek3, M. Becker1, J. Kusche2, E. Stanev3, T. AusderBeek4

STREMP  Team:  1)  Ins1tute  of  Geodesy,  Physical  and  Satellite  Geodesy  Sec1on,  Darmstadt  University  of  Technology      2)  Universität  Bonn    3)  Universität  Oldenburg/GKSS  Geesthacht  4)  Universität  Kassel  (CESR)/Universität  Heidelberg      5)  Universität  Na1onal  Oceanic  and  Atmospheric  Administra1on,  NOAA/OAR),  USA  6)  Italian Agency for Energy and Environment (ENEA), Climate Project - Roma, Italy 7)  LEGOS/CNES, 14, Avenue E. Belin, 31400 Toulouse, France      

Outline

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1.  Introduction

2.  Method - recent & long-term changes

3.  Results

4. Conclusion

.Introduction Methods I Results I Conclusions

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§  STREMP : Spatial and Temporal Resolution Limits for Regional Mass transPort and mass distribution

§  MED (2.5 106 km2), BLACK SEA (0.5 106 km2)

§  GRACE 2003-2010 §  pre-GRACE 1970-2003

Goals: mass change separation of mass and steric signal closure of water mass budget new regional Hydrological model improved ocean model in Black Sea

validation transport at GIBRALTAR from ocean model dominant modes of regional variability at decadal time scales understand the physical processes driving sea level & mass changes

.Introduction Methods I .Results I. Conclusions

!

(Aus der Beek, J.of Geod. 2011)

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§ Recent mass change §  GRACE vrs steric-corrected altimetry

§ Long-term mass change

steric-corrected – sea level reconstruction that combines long TG records & 2-D sea level patterns from -  altimetry and -  Regional Circulation Models (NEMOMED8-Meteofrance, Protheus System-Enea)

§ Recent & long-term mass transport

FGibraltar = EM - PM –RM – FB + dMM/dt

FBosphorus = PB – EB + RB – dMB/dt

Analysis: Basin averages and statistical analysis in 2D

.Introduction Methods I .Results I. Conclusions

Ocean Mass

Steric Sea Level

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.Introduction Methods I .Results I. Conclusions

Ø  ICA extracts statistically independent components which might be related to independent physical processes.

Blind source separation (BSS) based on assumption of – independence of the sources A suitable rotation makes the components as statistically independent as possible.

Principal Component Analysis versus Independent Component Analysis

(Forootan and Kusche JOG 2011)

2nd order statistics Eigenvalue decomposition of auto-covariance matrix

Higher order statistics (non-Gaussianity) - Gaussian: orthogonality = independence - non-Gaussian independence stronger than

orthogonality SICA : spatially independent

Cons: Mixing problem

Pro: Capture Max variability

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.Introduction Methods I .Results I. Conclusions

MASS-INDUCED SEA LEVEL Corr: 0.80 , Rms : 23 mm Ampl : 24 +/- 5 mm, ph: 319 deg (a-s) Ampl: 27 +/- 5 mm, ph: 359 deg (GRACE)

STERIC-SEA LEVEL Ampl.:58 mm, phase = 258 deg (MFSTEP) Ampl.: 66 mm, phase = 257 deg (GRACE)

SEA LEVEL Ampl: 70 mm, phase = 278 deg

Seasonal cycle

(Fenoglio et al., J.of Geod. 2012) HYDRO LEAKAGE: bigger annual amplitude as Watergap model

Al1metry  –  steric  =  GRACE  –  hydrological  leakage  

Good agreement in Amp and Phase that slightly depends on the steric and continental hydrology corrections choosen

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.Introduction Methods I .Results I. Conclusions

MASS-INDUCED SEA LEVEL Corr: 0.80 , Rms : 23 mm Trend: 8.3 +/- 1.6 mm/yr (MFSTEP)

2.9 +/- 1.6 mm/yr (ECCO) Trend: 5.3 +/- 1.9 mm/yr (Grace, Stocchi)

3.4 +/- 1.9 mm/yr (Grace, Paulson)

STERIC-SEA LEVEL Trend: -10.1 +/- 0.6 mm/yr (MFSTEP)

-3.1 +/- 0.4 mm/yr (ECCO) -5.3 +/- 1.1 mm/yr (GRACE)

SEA LEVEL Trend: 0.8 +/- 1.3 mm/yr

Long-term

(Fenoglio et al., J.of Geod. 2012)

Errors in : GIA (+/- 0.9 mm/yr) Steric (large) Continental Leakage (+/- 1 mm/yr)

Significant inter-annual variations occur (2003-2010 too short!)

Release R4 versus R5

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.Introduction Methods I .Results I. Conclusions

R4 R5 corr 0.80 0.82

Std (mm) 23 21

Release R4 versus R5

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§ Differences between R4 & R5 GFZ GRACE coeff. (diff are particularly big in GAD)

§ 

.Introduction Methods I .Results I. Conclusions

Mass induced sea level change

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.Introduction Methods I .Results I. Conclusions

SL reconstruction Meyssignac, GPC 2011

Mass-induced versus sea level change

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.Introduction Methods I .Results I. Conclusions

Percentage of variance explained in components

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.Introduction Methods I .Results I. Conclusions

Sea Level PCA ICA 1 52.6 46.3 2 24.7 19.9 3 12.7 17.6 4 8.7 10.0

Mass Change PCA ICA 1 42.5 39.8 2 22.6 19.3 3 12.8 14.3 4 8.4 12.8

Sea level from PCA and ICA

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.Introduction Methods I .Results I. Conclusions

Mass-induced sea level from PCA and ICA

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.Introduction Methods I .Results I. Conclusions

Mass-induced sea level from PCA and ICA

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.Introduction Methods I .Results I. Conclusions

Mass derivative

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.Introduction Methods I .Results I. Conclusions

Comparison  of  total  and  mass-­‐induced  sea  level  change      

Time derivative of Mediterranean Sea mass anomaly over 1970-2009.

Gibraltar water flux

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§ G  =  dSo/dt  –  Po+  Eo-­‐R  -­‐  B          § Exchange  dominated  by  E-­‐P  

§  Protheus model vrs observations : Corr, std = (0.6, 5.6 mm/mo)

.Introduction Methods I .Results I. Conclusions

Comparison  of  total  and  mass-­‐induced  sea  level  change      

STD mm/mo

Trend mm/mo/yr

E-P-R-B+dm/dt 9.1 0.7 +/-0.3

Gprotheus 7.9 0.4+/-0.2

(Fenoglio et al. GPC in press)

Large Scale climatic phenomen: NAO

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.Introduction Methods I .Results I. Conclusions

Corr

NAO dM/dt 0.6 NAO SLP 0.8 NAO P -0.7 NAO R -0.8

six-year running mean of DJFM yearly values of NAO index and anomalies of P, R sea level pressure, ∂M/∂t (NAO and SLP) are reversed)

Large Scale climatic phenomen: AMO

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.Introduction Methods I .Results I. Conclusions

Corr

AMO Eoaflux 0.9 six-­‐year  running  mean  of  yearly  values  of  the  AMO  index  and  of  OAFLUX  evapora1on  anomalies  (Fenoglio et al. GPC in press)  

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§  Validation of mass change and exchange from GRACE by alimetry and models §  Coherence of the different databases and their ability to describe the water cycle à

uncertainty estimate (for GIA, Hydrology leakage, steric from model) §  With R5 release improved dealising at regional scale (basins)

§  Long-term analysis of mass change extended by reconstruction to pre-GRACE interval : Interannual scales SL change explained by mass changes, small steric effect

§  Mass increase uniform, other components related to ocean circulation §  Independency of the phenomena at basin scale (ICA and PCA comparable results)

§  Mass change per year dM/dt is small wrt water fluxes (equilibrium condition) -> decadal variation in E-P drive changes in Gibraltar inflow,

§  Increase in net water flux at Gibraltar over 1970-2009 (0.8 +/- 0.2 mm/yr)

§  Important role of large-scale climate variability (NAO, AMO) in both sea level and mass changes need to be investigated further

.Introduction Methods I .Results I. Conclusions Conclusions and Outlook