Diapositiva 1

1
VANIMEDAT project Decadal and interdecadal
sea-level variability in the Mediterranean sea
and northeastern Atlantic ocean
A. Pascual1, M. Marcos2, S. Ruiz1, D. Gomis1, S.
Monserrat1, E. Alvarez3, B. Pérez3, M. G.
Sotillo3, G. Larnicol4, M. N. Tsimplis2 e-mail
ananda.pascual_at_uib.es 1 IMEDEA (CSIC-UIB),
Balears, SPAIN, 2 NOC, National Oceanographic
Center, Southampton, UK 3 Puertos del Estado,
Madrid, SPAIN 4 CLS Space Oceanography Division,
Toulouse, FRANCE
1. Objectives of VANIMEDAT project
3. Preliminary results
GENERAL OBJECTIVE Study of decadal and
interdecadal sea-level variability in the seas
surrounding the Iberian peninsula. (Project
funded by the Spanish Ministry of Science and
Education) SPECIFIC OBJECTIVES a)
Characterization of the spatial and temporal
sea-level variability. b) Quantification, at a
regional scale, of the different mechanisms that
drive sea-level variability. c) Estimation of
ocean mass increase.
MODEL INTERCOMPARISON (1993-2001)
HAMSOM
MOG2D
Barotropic sea level variance from each model.
TIDE GAUGE VARIANCE REDUCTION (1993-2001)
2. Data and models
Ratio of variance reduction at tide gauges
(Var(TG-IB)-Var(TG-model)/Var(TG-IB), in ,
for all frequencies (left), LF (gt20 days, centre)
and HF (lt20 days, right).

• Tide gauge data
• Hourly and monthly data.
• Period(1900-2006).
• Tides are filtered and atmospheric correction
• (IB/MOG2D/HAMSOM) is applied.

TIDE GAUGES VS ALTIMETRY (1993-2001)
HAMSOM
(Top) Position of gauges (hourly data) used for
the comparison with altimetry.
MOG2D

• Altimetry data
• Along-track processing
• Atmospheric correction (IB/MOG2D/HAMSOM)
• Usual other corrections
• Objective analysis
• Long wavelength error corrected.
• Weekly maps, 1/4º.
• Period 1993-present

Left Dubrovnik tide gauge (blue) and altimetry
(red) time series corrected by HAMSOM (top) and
MOG2D (bottom). Right Ratio of variance
reduction of the differences between altimetry
and tide gauge (Var(TG-alti)model-Var(TG-alti)
/Var(TG-alti)IB.
TP
Jason
ERS-1/2
SEA LEVEL TRENDS FROM ALTIMETRY
ALTI_MOG2D 1993-2006
ALTI_MOG2D 1993-2001
ENVISAT
Barotropic sea level models HAMSOM MOG2D Barocli
nic model to be run in the framework of
VANIMEDAT project.
mean 5.63 mm/yr mean 2.90 mm/yr
ALTI_HAMSOM 1993-2001
ALTI_IB 1993-2001
mean 5.39 mm/yr mean 5.48 mm/yr
4. Ongoing and future work
Configuration of the barotropic models.

• Combination of tide gauge and altimetry data to
  reconstruct sea level in the last century.
• Characterization of heat fluxes from REMO.
• To run a baroclinic numerical model to extract
  the steric component.
• Use of GRACE and GOCE data to extract the mass
  component.

GRACE
GOCE