Overview of the Sea Level research activities in France Indo-French collaboration : current status and perspective

L. Testut(1)(2), A. S. Unnikrishnan(2), M. Lengaigne(3)(2), A. G. Nidheesh(2), A.K. Shukla(2), Babu(2), I. Suresh(2), … (1) LEGOS, Toulouse, France (2) NIO, Goa, India (3) LOCEAN, Paris (4) ISRO, Ahmedaba, India

Tide Gauges

Satellite Altimetry

Tide Modeling

Long Term Seal Level Change

My Background L. Testut LEGOS/NIO

http://www.legos.obs-mip.fr/observations/rosame

Objectives

• Observation • Modeling

• Show some examples of the existing collaboration between India and France relative to sea level studies

• Visit INCOIS, meet people and share experiences and skills and why not start new collaboration on sea level

Tidal Modeling on the west coast of India

Testut L.(1)(2), Unnikrishnan A.S.(1)

(1) NIO, Goa (2) LEGOS, Toulouse

1stJOINT ISRO/CNES CAL/VAL EXPERIMENT

SAC/NIO/LEGOS/CNRS

Gulf of Khambhat

350 Km

M2 > 3m.

J1N Harmonics Constituents

FES2004

NOISE

SIGNAL

The tidal model

• t-UGOm (Toulouse Unstructured Grid Ocean model 2D, ex-Mog2D) – 2D barotropic model

– Using finite element for the spatial discretization of the mesh

– Based on the non-linear shallow water equations (Lynch and Gray, 1979)

– Without assimilation

– We have run the model for the principal tidal waves (M2,K1,O1,P1,S2,….)

• Forced at the boundaries with Altimetry with (CTOH harmonical products)

• Used the ETOPO2 modified bathymetry (Sindhu et al., 2007)

M2

M2 M4

Validation at the coast

MODEL OBSERVATION

amplitude

phase southward northward

MODEL RSS(cm)

t-UGOm 3.7

GOT4.7 3.7

FES2012-HYDRO 4.8

FES2004 5.5

MODEL RSS(cm)

t-UGOm 22.3

GOT4.7 29.7

FES2012-HYDRO 29.7

FES2004 70.3

FES2004

t-UGOm

NOISE

SIGNAL

It’s really better …. but not good enough !!

Modeling perspective Arabian Sea Bay of Bengal

Mouth of the Ganges

ADCIRC / TUGO / SELFE / TELEMAC ?

Band-Aid : Belmont Forum project 2 years Contract starting this year

www.sonel.org

Message

• Importance of the installation of GPS@Tide Gauge

• This is a new requirement of the GLOSS implementation Plan

Conclusion

• India and France both had a long and rich experience on sea level observation.

• Since last year we also share the success of the launch of an innovative satellite altimetric mission (SARAL/AltiKa)

• INCOIS is a focal point regarding the sea level studies : observation and modeling (tsunami).