COVER LETTER CNES Proposal Cover Sheet NASA/CNES Research Announcement

COVER LETTER
CNES Proposal Cover Sheet
NASA/CNES Research Announcement SALP-BC-MA-EA-14810-CN
Proposal No.
Title:
_____________________ (Leave Blank for NASA/CNES Use)
HIGH STANDARD TIDE GAUGE NETWORK FOR SCIENTIFIC STUDIES
Principal Investigator:
Name: LAURENT TESTUT
__________________________________________________
Department:_______________________________________________________________
Institution: __LEGOS – UMR5566 (CNRS/CNES/UPS/IRD)___________________
Street/PO Box: _14, av. Edouard Belin_____________________________________
City: __Toulouse__________
State: ___________
Zip: _31401 Cedex 9 ___
Country: _FRANCE__________ E-mail: [email protected] _____________
Telephone: _05.61.33.27.85________ Fax: __05.61.25.32.05_________________
Co-Investigators:
Name
Institution
Florent Lyard
Gwéanële Jan
Stéphane Calmant
LEGOS
NOVELTIS
LEGOS
Telephone
33.5.61.33.29.88
33.5.62.88.11.07
33.5.61.33.29.37
Budget (for U.S. and French Investigators only):
1st Year:52 kEuros__2nd Year:40 kEuros __3rd Year:35 kEuros __4th Year:25 kEuros
Total: 152 kEuros ___
Authorizing Official: _Patrick MONFRAY__
(Name)
__Directeur, LEGOS____
(Institution)
1
TABLE OF CONTENTS
COVER LETTER ...................................................................................................................1
TABLE OF CONTENTS........................................................................................................2
INDENTIFYING INFORMATION .......................................................................................3
III.1 Title .............................................................................................................................3
III.2 Principal Investigator ..................................................................................................3
III.3 Co-Investigators ..........................................................................................................3
III.4 Collaborations .............................................................................................................3
INVESTIGATION AND TECHNICAL PLAN.....................................................................4
IV.1 Summary.....................................................................................................................4
IV.2 Objectives ...................................................................................................................4
IV.3 Approach.....................................................................................................................5
IV.3.1 Presentation of the network .................................................................................5
IV.3.1.1 South Indian and Austral Ocean ...................................................................6
IV.3.1.2 Atlantic Ocean ..............................................................................................6
IV.3.1.3 Pacific Ocean ................................................................................................7
IV.3.1.4 Mediterranean sea.........................................................................................7
IV.4 Experimental and Work Plan......................................................................................8
IV.4.1 Work Package 1: Design a high standard tide gauge network ............................8
Task 1.1: Upgrade and manage the network.............................................................10
Task 1.2: Quality control and data distribution ........................................................11
IV.4.2 Work Package 2: Scientific cross-verification experiments ..............................12
Task 2.1: Validation of dedicated coastal altimetry products...................................12
Task 2.2: Contribution to regional multi-mission calibration...................................12
Task 2.3: Monitoring of variable and absolute transport of currents........................12
Task 2.4: Numerical ocean models for coastal and off-shore ocean dynamic
connection .................................................................................................................13
IV.4.4 Work Package 3: Coordination and Synthesis...................................................15
IV.5 Anticipated Results and Significance of the Investigation .......................................15
IV.6 References.................................................................................................................16
MANAGEMENT PLAN AND COST .................................................................................17
V.1 Management Plan.......................................................................................................17
V.2 Cost Plan ....................................................................................................................18
2
INDENTIFYING INFORMATION
III.1 Title
HIGH STANDARD TIDE GAUGE NETWORK FOR SCIENTIFIC STUDIES
III.2 Principal Investigator
Related topic : In situ data & Indian and Austral part of the network
Laurent Testut
UMR5566 (CNRS/CNES/UPS/IRD)
LEGOS, 14 Av. Edouard Belin, 31400 Toulouse
Tel:33.5.61.33.27.85, Fax:33.5.61.25.32.05
E-mail: [email protected]
III.3 Co-Investigators
Related topic : Oceanographic aspect (modelling) & Mediterranean part of the network
Florent Lyard
UMR5566 (CNRS/CNES/UPS/IRD)
LEGOS, 14 Av. Edouard Belin, 31400 Toulouse
Tel:33.5.61.33.29.88, Fax:33.5.61.25.32.05
E-mail: [email protected]
Related topic : Coastal Altimetry
Gwénaële Jan
NOVELTIS
Parc Technologique du Canal. 2, Av. de l’Europe
31520 Ramonville St Agne
Tel : 33.5.62.88.11.07
E-mail :[email protected]
Related topic : Geodetic aspect & Pacific part of the network
Stéphane Calmant
UMR5566 (CNRS/CNES/UPS/IRD)
LEGOS, 14 Av. Edouard Belin, 31400 Toulouse
Tel:33.5.61.33.29.37, Fax:33.5.61.25.32.05
E-mail: [email protected]
III.4 Collaborations
The Southern Indian oceanographic studies will be made in collaboration with H.Y Park
of the National French Museum.
The treatment of the GPS buoy will be made through the collaboration of the OSU (Ohio
State University) by C.K. Shum and K. Sheng
The treatment of the permanent GPS will be made by the SONEL team Guy Woppëlmann
and Marie-Noëlle Bouin in the Frame of the TIGA project.
Calibration purposes of this proposal will be made in collaboration with P. Bonnefond
(CERGA)
Comparison/validation using the Ibiza tide gauge data will be done through a
collaboration with Simon Ruiz (Mallorca University) and Begonha Perez Gomez (Clima
Maritimo Puertos del Estado)
Internal collaboration with P. De Mey and R. Morrow of LEGOS is planned.
3
INVESTIGATION AND TECHNICAL PLAN
IV.1 Summary
This proposal aimed to bring together a certain number of tide gauges distributed on
different part of the global ocean in order to build a coherent sea level network. From a
technical point of view the aim is to build a network of reference for scientific studies. This
network exist, it is at the moment constituted of a set of tide gauges located on Islands in
Atlantic, Indian, Pacific, Austral ocean and Mediterranean sea. All these sites are
administrated by different persons of LEGOS for different scientific purposes. We propose to
upgrade these sites in order to fulfil our scientific objectives and to maintain this network on a
long term base. Different experiments will be undertaken through this proposal regarding:
• Drift control of pressure sensor and calibration experiments
• Fast delivery quality control and data filtering for assimilation studies.
• Assessment of geophysical corrections applied to coastal altimetry and validation
with in situ data.
• Regional multi-missions calibration
• Transport monitoring from tide gauges and altimetry.
• Link between coastal and off-shore sea level, using altimetry, tide gauges and
models.
• Assimilation experiments
• High frequency response of the ocean to pressure and wind forcing using a
barotropic two dimensional model.
• Long term evolution of the sea level, recommendations for in situ networks.
IV.2 Objectives
The comparison between sea level derived from satellite altimetry and sea level
derived from tide gauges has proved to be of major technical and scientific interest. From the
beginning of the altimetric mission tide gauges have been used to estimate the reliability and
accuracy of the satellite altimeter. Tide gauge is presently the reference instrument used for
absolute calibration of altimetric mission (Ménard et al, 1994). Moreover, the use of the
global distribution of the tide gauges provided by the GLOSS data bank permit to monitor the
stability of the satellite altimeter (Mitchum, 1998). On the other hand the accuracy of the T/P
and Jason mission is now able to identify some of the particular bias of tide gauges such as
sensor drift or appreciable land movement (Cazenave, 1999). The comparison of both
instruments was also very fruitful for sea level rise studies. The existence in some countries of
long sea level time series that cover for some of them the whole 20th century was at the origin
of the first reliable estimation of recent sea level rise. These estimates of the global sea level
rise are based on historical tide gauge data maintained by the Permanent Service for Mean Sea
Level (PSMSL) (Spencer et Woodworth, 1993). Now, the coverage allowed by satellite
combined with the accuracy of altimetric sea level has greatly improved our knowledge of the
response of the ocean to the climate change in the past ten years, especially in the open ocean
where in situ sea level measurements were inexistent. As an example, the quasi global sea
level rise given by the analysis of the trend of more than ten years of T/P data has shown that
previous estimate given by tide gauges can be biased because of the non homogenous
4
geographical distribution of tide gauges (Cabannes, 2001). But maps of altimetric derived sea
level trend also shows strong regional differences that are probably influenced by the decadal
variability of the ocean.
Our approach is to use already existent sites relatively well distributed around the
world ocean. We will then have a relatively representative situation and propose to
maintained or update these sites on a long term base in order to make a network of highly
controlled sea level gauges able to be useful for altimeter calibration and for scientific
applications. One of the underlying objective of this proposal is also to put the foundations of
a permanent sea level network able to produce in the future a highly reliable estimate of the
sea level trend on the different part of the ocean. Indeed a great care will be taken to the
monitoring of the sensor drift, of the vertical motion and on the representativeness of each site
in term of sea level variability.
One of the scientific objective we will pursue within this proposal is to better
understand the link between the open ocean sea level variability measured by satellite
altimeter and the coastal sea level variability measured by sea level gauges. Differences
between this two measurements of the same quantity may be due to:
-
Dynamical processes occurring in the coastal area and not present off shore or vice
versa
Weakness in the geophysical corrections applied to the altimetric range
To better understand this link we will study in parallel the weight of these contributions at
the different sites of the network and with different approaches (cf. WP 2).
IV.3 Approach
IV.3.1 Presentation of the network
Due to the presence of several institutes which composed the LEGOS
(IRD/CNRS/CNRS/UPS), this laboratory is in charge de facto of a number of sea level gauges
which will probably be extended in the next few years. Historically these gauges was installed
for different scientific purposes: monitoring of the long term sea level trend, monitoring of the
Antarctic Circumpolar Current, vertical land movement studies, calibration of satellite
altimeter, etc…. These sites shows strong differences in terms of maintenance, bench mark
control, access time of data, etc. One of the main objective of this proposal is to update
some of these sites in order to have an homogenous network in term of quality and to the
end to build a high standard sea level reference network.
5
Figure 1 : Tide gauges core network. All theses sites are presently operational (except Clipperton and
Futuna that are scheduled)
IV.3.1.1 South Indian and Austral Ocean
The LEGOS is in charge for many years now of the Observation Service ROSAME
tide gauges network (Réseau d’Observation Antarctique et Sub-antarctique du niveau de la
MEr). This network is composed of four permanent tide gauges located on islands in the
southern part of the Indian Ocean in Kerguelen, Crozet and Saint-Paul and in Dumont
d’Urville in Antarctica. This network was labelled in 1997 by INSU (Institut National des
Sciences de l’Univers) and is founded by INSU and IPEV (Institut Paul Emile Victor) as
Observation Service.
¾
Kerguelen Island is equipped with a real time pressure gauge station since 1993.
It has an IGS (International GPS Service) permanent GPS at 3 km away from the
tide gauge at the CNES station and a DORIS beacon. This station needs to be
doubled. A radar sensor is envisaged for sensor inter-calibration purposes. First
GPS measurements near the tide gauge and levelling were made during the
maintenance campaign in january 2003. The installation of a permanent GPS at 50
m of the tide gauge is scheduled as a yearly levelling campaign. A GPS buoy
levelling would be of great interest for altimeter calibration and ocean studies (as
in Saint-Paul).
¾
Saint-Paul Island is equipped with a real time pressure gauge station since 1994.
Due to mask problem GPS is problematic on this Island. Amsterdam Island 80 km
away from Saint-Paul have a DORIS beacon. This station needs to be updated.
¾Crozet Island is equipped with a real time pressure gauge station since 1995.
This island will be equipped with a DORIS beacon in november 2003 and GPS
measurements and levelling are scheduled during the next maintenance campaign
in December 2003. In the next 2 years a GPS will be installed at Crozet.
¾
Dumont d’Urville is equipped with a real time pressure gauge station since 1997.
This site is equipped with DORIS and permanent GPS.
IV.3.1.2 Atlantic Ocean
6
¾
Sao Tomé Island is equipped with a real time pressure gauge station since 1999
but have record since 1988. This tide is managed by LEGOS. Recent study shows
that this site has a good potential to be a absolute site of satellite altimeter
calibration (Aman et al., 2003). A maintenance is scheduled in february 2004 with
a full levelling program and a GPS buoy campaign to determine the geoid between
the tide gauge and the Jason and Envisat ground tracks. Meteorological station
installation is on the way at the opposite side of the island.
¾
Abidjan in Ivory Coast and Pointe Noire in Congo will probably be reinstalled in
collaboration with the LEGOS in the next few years. These two sites are included
in the GAINS proposal leads by P. Woodworth submitted in september 2003 at the
6th European Framework Program. These two tide gauges have a great scientific
interest regarding the study of the propagation of the coastal upwelling along the
Gulf of Guinea.
IV.3.1.3 Pacific Ocean
The Pacific network of LEGOS tide gauges was primarily established for tectonics
purposes.
¾
Sabine and Wusi pairs of bottom pressure gauges are on both rims of the New
Hebrides subduction zone, where Sabine is stable and Wusi experiences crustal
motions, although they are only a few tens of km apart. Both sensors have been
purchased with IRD and PNTS funds, and are maintained by IRD and TOA funds
since S. Calmant has been selected as a T/P PI for this experiment.
¾Futuna will be set to complete the geodetic network surveyed on this island to
monitor the co-seismic and inter-seismic crustal motions. It is funded by French
Overseas Ministry. It will be maintained with IRD funds.
¾
Clipperton is not planned on a specific scientific project but moreover because,
given its remoteness, data collected there will have a dramatic importance for all
scientific applications using sea levels in Eastern Equatorial Pacific (including
internal Tides, El Nino, Tsunamy warning, regional and global oceanic circulation)
and/or tecto-geodesy (absolute motion of the Pacific plate, reference frame for
GPS campaigns in this part of the Earth, orbit improvement through distribution to
IGS services). This site needs a complete autonomous and automatic station.
¾
Our team had long scheduled to install a Tide Gauge in Marquesas Island in order
to replace those that felt out of order in the late 90's. The French ministry has just
funded two in particular to participate to the Pacific Tsunami warning network. An
agreement is foreseen with this organization for collecting these data, and apply
them all our test and analyses procedures. Also, in order to meet our scientific
requirements on the control for the stability of the tide gauge, we plan to install in
2004 a permanent GPS station. The GPS station will be maintained by our team in
collaboration with the IRD Centre at Papeete and the University of French
Polynesia, together with the local contacts that the Tsunami warning network
established there.
IV.3.1.4 Mediterranean sea
¾
Macinaggio: Pressure gauge is installed and maintained by LEGOS since june
2003. This site was levelled and GPS buoy levelling between Capraia and
7
Macinaggio is scheduled. This site needs to be provided with a meteorological
station and an other pressure gauge for sensor inter-calibration.
¾
Capraia: Pressure gauge is already installed by ENEA (Italy) and University of
Bologne and Pise. A new sensor will be installed in november 2003 through a
Franco(CNES)-Italian collaboration.
¾
Ibiza: Pressure gauge maintained by Spain (University of Majorque & University
de Barcelone and Puertos del Estado) since june 2003 through a French Spanish
collaboration.
¾
Senetosa: 3 Pressure gauges installed and maintained by CNES-CERGANOVELTIS since 1998 for absolute calibration purposes.
¾
Sète and Banyuls are scheduled.
IV.4 Experimental and Work Plan
IV.4.1 Work Package 1: Design a high standard tide gauge network
The first action aimed to design, manage and upgrade the network in order to:
• Answer to our scientific objectives
• Insure data quality and data distribution
• Maintain the durability of the network
Technical requirements for each site are :
9
High quality pressure gauge sensor (+ temperature and conductivity)
9
Installed auto-calibration system on each site in order to follow the sensor drifts
9
Reliable atmospheric pressure data
9
Real time access to data (via satellite or modem transmission)
9
Permanent GPS or frequent GPS campaign in the vicinity of the gauge
9
Yearly maintenance of site in particular with levelling.
9
GPS buoy levelling between the TG and the satellite track
To illustrate some of the points cited above we will look at the impact of sensors drift or land
movement on sea level rise estimation:
Bottom pressure drift
Bottom pressure gauges are at the moment the most accurate sensors for sea level
monitoring. It is supposed also to have a good long-term stability. But sensors need to be
recalibrate at least twice a year for a real control of the drift, instead of what, drift could be
large as shown on figure 2.
Figure 2 : The bottom pressure sensor n°1351
remained more than 4 years in the Port of Français
at Kerguelen Island because of technical and
logistical problems. This sensor has been recalibrated by the manufacturer after that period
Then the raw data of july and august 1997 (its last
period into the water) were recomputed with the
new calibration coefficients. After 4 years into the
water the sensor has drift of more than 7 mbar,
which in term of sea level trend represents more
than 17 mm/y. Everyone can see the importance of
sensor drift control, especially for sea level studies.
8
Atmospheric pressure drift
Another example of discrepancies brought by sensors lack of control is the observed
drift in the barometric pressure. The barometric pressure sensor is used to derive sea level
from the bottom pressure according to the formula: Pb-Pa/(ρg).
Figure 3 : Differences of barometric pressure
recorded at the meteorological station of
Kerguelen and pressure recorded by the tide
gauge station from 1993 to 2001. The relative drift
of barometer of the tide gauge station is estimated
at –0.7 mbar/y with a strong seasonal shape.
Strong discrepancies occurring in 2000 comes
from erroneous data from the meteorological
station. After correction of this drift the sea level
rise calculated at Kerguelen fall down from 10.78
mm/y to 2.63 mm/y.
Vertical land movement:
Figure 4 : Wusi bank experienced an earthquake that create a 4 cm offset vertical movement. Only a fine
analysis of the time series of sea level recorded by the tide gauge could identified this offset. It was in Oct
2000 !
That is why we choose to finely survey our network of tide gauges. Vertical land
motions are often blamed as the origin of disagreement when in situ sea level are compared to
altimetric one, but this is not always ascertained. First, we will put effort in installing
permanent GPS stations at each tide gauge station. When not possible, we will pay attention
to regularly survey the offset between the tide gauge reference marks and the network of
permanent GPS stations. In that goal, the GPS station closest to the tide gauge of our network
9
will be included in the TIGA network managed in the frame of SONEL (G. Woppëlmann and
M.N. Bouin). By this way, the vertical position of our network will be monitored in a global
reference frame. At last, globally referenced time series of sea level will be produced enabling
computation of slopes from one tide gauge to the other one for either oceanographic
applications and extended comparison with altimetry.
Task 1.1: Upgrade and manage the network
Gps Buoy Levelling
Local Assistance
Y
-
Y
2 Saint-Paul
3 Crozet
Y
Y
Y
Y
Y
Y
Y
Y
Y
S
-
Y
4 D. d’Urville
5 Sao Tome
Y
Y
Y
Y
Y
Y
Y
-
Y
-
-
Y
S
Y
Y
6 Sabine bank
7 Wusi bank
Y
Y
-
Y
Y
S
-
-
Y
Y
-
8 Futuna
Y
-
Y
Y
Y
-
Y
-
Y
9 Macinagio
10 Capraia
Y
Y
-
-
-
-
-
Y
Y
S
S
Y
Y
11 Clipperton
12 Sète
-
-
-
-
-
-
-
-
Y
13 Banyuls
14 Nouméa
15 Marquises
Y
S
Y
S
Y
Y
-
Y
-
Y
-
Y
S
S
-
Y
Y
Y
16 Ibiza
17 Senetosa
Y
Y
Y
-
Y
Y
Y
Y
-
-
Y
Y
Y
Y
Y
Y
18 Abidjan
19 Pointe Noire
S
S
S
S
-
-
-
-
S
S
-
Y
Y
-
Tableau 1 : This table lists the tide gauges where LEGOS appears as principal administrator (grey
background) or as collaborator (n°14 20). It summarizes some of the present characteristics of the
network inside the black frame and points out the future needs (black dots ). The Sensor Calibration
item corresponds to the need of a reliable on site calibration method (mainly to control offsets and drifts
in the data). When a black dot appears in the Update site item, that is to say the station is old and need to
be updated or replaced by a new one. Meteorological Station points out the need of reliable atmospheric
pressure data near the tide gauge, it is often the case when no airport or METEO Stations are in the
vicinity of the tide gauge. Install GPS points out the need to install a permanent GPS station and GPS
buoy levelling the needs to related the sea surface height at the tide gauge to the sea surface height under
the satellite track. Real Time point out the need of satellite transmission of the data in near real time.
Some of the site nearly fulfil the technical requirements cited above (ex: Kerguelen, Noumea, Futuna).
Italic sites are scheduled sites. [Y=Yes, S=Scheduled]
10
RealTIme
Levelled
Y
Install GPS
Moorings
Y
GPS buoy Levelling
DORIS
Y
Meteorological
Station
Permanent GPS
Y
Update site
Meteorological
Station
Y
Sensor Calibration
Real Time
Y
Station Name
1 Kerguelen
N°
Operational.
This work package consist in upgrading some of the equipment, install real time
station, install GPS near/or at tide gauge, initiate levelling program, deploy moorings, etc.
Task 1.2: Quality control and data distribution
An automatic acquisition/quality control/fast delivery software for real time follow up
of the data coming from a tide gauge network is presently developed in the LEGOS
laboratory, a version of this software is at the moment in test on the ROSAME tide gauges (cf.
Figure 5). Soon this software will able to detect:
•
•
•
•
Initialisation messages send by tide gauges station when maintenance operation is
in hand.
If same Argos message is always received
If there no message received
If an error arises during the automatic processing steps (date, threshold, gaps)
Future developments will concern the scientific validation of the data:
• Harmonic analyses and tidal prediction
• Data filtering and comparison with tidal model
• Etc…
Figure 5 : Schema of the automatic software presently developed at LEGOS for the ROSAME network.
In 2004 ROSAME and Sao Tomé database will be weekly updated an anonymous ftp
site. All the future data treated and controlled at LEGOS by this software will be available on
weekly base for national (SONEL), european (ESEAS) and international (GLOSS) database.
In the future we expect to deliver our data on daily bases when all steps of the software will
be optimised.
This WP package also aimed to define quality control and standard format of fast
delivery distribution of in situ tide gauges sea level data for assimilation purposes.
11
IV.4.2 Work Package 2: Scientific cross-verification experiments
This work package intends to validate the tide gauge products through a set of scientific
applications where numerical ocean models and in situ/space observations are involved.
Task 2.1: Validation of dedicated coastal altimetry products
Advanced coastal altimetric products proposed by the CTOH (see R. Morrow’s
OST/ST proposal) at 5 test sites, including the Albicocca experimental site, will be
developped in collaboration with the Pôle d’Océanographie Côtière and Noveltis. Altimetric
data products will have improved wet and dry troposphere corrections, ionospheric correction,
tidal and high-frequency barotropic response corrections, and a new mean sea surface. These
coastal altimetric products will be fully compared with Capraia and Maccinagio tide gauges
measurements. This study will be extended in the future to the other LEGOS tide gauges.
Task 2.2: Contribution to regional multi-mission calibration
In-situ calibration of altimeter sea surface height is usually done at the vertical of a
dedicated Cal/Val site, by directly comparing altimetric data with in-situ sea level data.
Recently, Noveltis and CNES altimetry team have extend the calibration opportunities by
using, not only over-flying passes, but also satellite passes located far away from the Cal/Val
site. In such a case, two main effects interfere in the SSH bias determination, the geoid slope
and the ocean dynamics. In order to correct from the geoid slope, distant SSH altimetric data
are propagated along a succession of known 11 years of Topex-Poseidon and Jason altimetric
mean sea level profiles up to the in-situ reference site. Ocean dynamics differential effect
which is becoming larger as the distance from the site is increasing, is corrected by using
ocean numerical MOG2D model. This method was first tested at the Senetosa site (Corsica)
with a Jason-1 data set then, applied to Topex-Poseidon on its new orbit and to GFO, using
NOAA-GDR. The promising results of works initiated with the method on Jason-1, T/P and
GFO (2003), make us confident in proposing tandem experiences to demonstrate the capacity
of this technique to rebuilt SSH time series as complete as possible, estimating an error
budget associated to the use of a whole of heterogeneous altimeter measurements (T/P, Jason1,ENVISAT,GFO, the next WSOA).This method is applicable to any altimetric satellite,
assuming that there is an accurate mean altimetric profile available over the Cal/Val site to
connect off-shore altimetric data with in-situ data. It will be applied to some of the LEGOS
tides gauges mainly in Pacific and Mediterranean Sea (in collaboration with P. Bonnefond’s
OST/ST proposal).
Task 2.3: Monitoring of variable and absolute transport of currents
The barotropic transport intensity (or variability) of a current can be calculated from
the sea level across slope following the quasi-geostrophic balance. Then comparing
referenced tide gauges measurement on either side of a current would permit in theory to
reconstitute the transport variability time series. Two currents will be concerned by this study
at two different scale:
12
• The Ligurian Current (LC) flow through the Corsica Channel.
A special focus will be given to the Ligurian transport through the Corsica Channel. This
transport is of high scientific and environmental interest as it represents most of the northern
current transport, circulating from the
Italian Rivera to the Spanish waters. The
central jet is located between the
Macinaggio (Corsica) and Capraia island
(Italy) tide gauge site. The jet is mainly
barotropic, as demonstrated by earlier
surveys, and its intensity can be deduced
from the sea level across slope, following
the quasi-geostrophic balance. The jet
absolute transport direct estimate would
need to determinate the marine geoids
with a very high accuracy (about 15
centimeters on a 30 kilometers distance),
which is on the edge of available
technology (airborne gravimetry). The
practical feasibility and the funding of
such a gravimetric survey is under
investigation. Meanwhile, our strategy will
be to estimate the absolute transport by Figure 6 : Northwestern Mediterranean schematic
sampling the velocity and density profile ocean circulation
along the jet cross section using the
instruments of the Thetis research vessel (INSU). Close to this section, the transport
variability will be estimated from the altimetric measurements and then compared to the tide
gauge estimates to investigate the accuracy of using altimetry observation for coastal ocean
circulation monitoring.
•
The Antarctic Circumpolar Current (ACC) is the most important current of the
ocean in term of transport. Its role is crucial from a climatic point of view. Then
variation of its transport are fundamental to understand and/or to model the future
climate variation. During its travel around Antarctica ACC flow in between Kerguelen
and Saint-Paul Islands where two long time series of sea level are available (from
1995 up to now). This two sites are “joined” by the T/P and Jason satellite track
n°103.
For these two sites the transport variability will be estimated from the altimetric
measurements and then compared to the tide gauge estimates to investigate the accuracy of
using altimetry observation for coastal and open ocean circulation monitoring.
Task 2.4: Numerical ocean models for coastal and off-shore ocean dynamic
connection
The long term sea level monitoring faces a never-ending challenge: gathering high
quality, continuous measurements representative of the regional ocean dynamic. For technical
reasons, coastal observations can insure the measurements control requirements, when
satellite altimetry offers the open ocean cover. At the moment, none of the previous
observations systems can satisfy alone for the needs of the long term sea level monitoring.
Combined use of altimeter and in situ observations is then necessary, and ocean numerical
models are needed to perform this combination. This task intends to explore the efficiency
13
and limits of this approach from the present models and observation networks by intercomparing them together. This step can be seen as a prior exploration phase necessary before
data assimilation (quantitative comparison, departure investigation). The approach will be
tested on several experimental cases. Focus is put on the Northwest Mediterranean Sea, the
Kerguelen Plateau region and applications related to the global ocean response to atmospheric
forcing (C. Le Provost’s OST/ST). Our approach to analyze coastal-off-shore connections will
consist in computing dynamical correlations and calculate space-time representers. This work
will be done in collboration with P. De Mey. Our network will also provide data after quality
control and appropriate filtering for assimilation experiments. A quantitative comparison will
be done with the model before assimilation.
¾
Northwest Mediterranean Sea
Figure 7: MFSTEP NWMD regional ocean circulation
model extent
We will be provided with realistic
regional circulation simulations
(MFSTEP,
NWMED
regional
model, (MEDCAL, ALBICOCCA).
3D circulation models are necessary
to investigate the tide gauge, XBT’s
and altimetric measurements content.
The usability of satellite data for
shelf
and
coastal
circulation
application is one of the key question
for the future high resolution
missions like WSOA. Our objective
here is not only to use model
simulations to validate our approach,
but also to provide some prospective
insights on coastal oceanography
from space.
¾
Austral Ocean
This study aimed to analyse the high frequency response of the ocean at small scale (in
the Bay of Morbihan) and at larger scale on the plateau of Kerguelen and in the South Indian
ocean. The regional model will be forced at its boundary by the global MOG2D model. This
study will help to understand the transfer function between the signal in the open ocean
measured by T/P and Jason (Yoon et al, 1997) and the signal measured by the tide gauge at
Kerguelen, this will be made in connection with the OST/ST Proposal made by H.Y. Park of
French National Museum in Paris. We will also expect in this comparison to point out
weakness in the geophysical corrections of the alimeter and expect to discriminate between
these weakness and the dynamical difference. A better understanding of this transfer function
will permit a posteriori to reanalyse the 11 year of comparison of both signals and then
improve the significance of the variability.
14
Figure 8 : Finite Element
Mesh of the MOG2D
model around Kerguelen.
One can see the very high
resolution of the mesh
around the Island where
depth is small and on the
steepest slope of the
plateau. This regional
model will be boundary
forced by the global
version of the MOG2D
model.
We will also compare in situ data with existing products:
3D existing products:
MERCATOR: PAM (OPA model, Atlantic/Mediterranean Sea 1/15°°, assimilation)
MERCATOR: POG (OPA model, global ocean,1/4°)
MFSTEP: GCM (OPA model, 1/16°, assimilation)
MFSTEP: NWMED (SYMPHONIE model, 3km, assimilation, nested in MFSTEP GCM)
2D existing products:
ALBICOCCA: MEDCAL (Mog2D model, variable resolution from1km up to 20 km,
assimilation)
IV.4.4 Work Package 3: Coordination and Synthesis
Due to the geographical disparities of the sites and to the presence of many actors
involved in the maintenance of each sites (geodesist, technicians, oceanographers), a good
coordination is essential to succeed in doing this network a reference. This WP mainly
consists of reunions of all the people directly involved in this proposal and/or in the
maintenance of each site and of the people interested by the different aspects studied
(technical, altimetry, modelling, ocean circulation). Travel costs for external collaborators
will be asked in this proposal to organised these reunions. Scientific publications costs and
participation to scientific meetings (SWT, EGS, AGU) will also be asked for this WP.
We also want to produce recommendations for Tide Gauges Installation, Sensor
Calibration (how to monitor drifts), Data Quality Control.
IV.5 Anticipated Results and Significance of the Investigation
With this proposal we except to :
•
•
Build a excellence network in virtue of its technical characteristics and
geographical coverage.
Improve estimate and confidence on sea level trend derived by tide gauges.
15
•
•
•
•
•
•
•
Ascertain the crustal contribution to the sea level trend recorded by tide gauges
Link the sea level recorded by tide gauges to the sea level measured by altimeter in
terms of absolute height.
Cross-validated sea level measurements using models, assimilation experiments
and observations (satellite and in situ)
Improve the assessment of the error budget of the geophysical correction applied
to altimetric range near the coast.
Better predict the high frequency sea level response to external atmospheric
forcing and then be able in connection with the modelling to improve altimetric
dealiasing.
Be able to determine and quantify for a tide gauge sea level record the part of the
typical coastal signal from the offshore ocean signal.
Generate a set of very high quality sea level data on coastal region available for the
future validation of the SWOA.
IV.6 References
Aman A., L. Testut, S. Arnault, G. Eldin, Y. du Penhoat, B. Bourles and P. Téchine. 2003. Seasonal upwelling
in the Gulf of Guinea from altimetry and tide gauge. In prep
Cabannes C., Cazenave A. and C. Le Provost, 2001 : Sea Level Rise during the 1990s and past 40 years: New
insight from satellite and in situ observations, Science, 294, 840-842.
Calmant S., CK Shum, K. Cheng, W. Scherer and M. bevis, Earthquake-related offsets in sea levels recorded by
Tide Gauges, 2 recents examples in Vanuatu, South West pacific, Workshop of vertical crustal motion and
sea level change, CGPS@TG), Toulouse, 17-19 Septembre, 2002
Calmant S., Cheng, K., Jan, G., Shum C., and Y. Yi, Comparison of sea surface heights by JASON and ocean
bottom gauges: the MOTEVAS project (SW Pacific), soumis à Marine Geodesy
Calmant S., K. Cheng and C. K. Shum, Sea level series and GPS surveys along the ground tracks of satellite
altimeters overflying the tide gauges of the MOTEVAS project, EGS, Nice, 6-11 Avril 2003.
Cheng K., C. Shum, Y. Yi, S. Calmant, and D. Martin, Absolute radar altimeter calibration using GPS water
level measurements, GLOSS GE7 Meeting, Univ. of Hawaii, Honolulu, Hawaii, April23-27, 2001.
Carrere, L. and F. Lyard (2003), Modeling the barotropic response of the global ocean to atmospheric wind and
pressure forcing - comparisons with observations, G. R. L., Vol 30, N°6, 1275.
Cazenave A., Dominh K., Soudarin L., Ponchaut F. and C. Le Provost, 1999 : Sea level changes from TOPEXPOSEIDON altimetry and tide gauges and vertical crustal motion. Geophys. Res. Lett., 26, 2077-2080.
Faillot, M. Etalonnage de données altimetriques sur sites non dédies. Rapport de fin d’études 2003.
ENSIETA/CNES.
Kummerow, C. 1993, On the accuracy of the Eddington approximation for radiative transfer in the microwave
frequencies, Journal of Geophysical Research, 98, D2.
Lyard, F. , F. Ponchaut, and C. Le Provost (1999) Long period tides in the global ocean from a high resolution
hydrodynamic model and tide gauge data assimilation, Internal report, LEGOS.
Ménard, Y., E. Jeansou, and P. Vincent, Calibration of the TOPEX/POSEIDON altimeters at Lampedusa:
Additional results at Harvest, J. Geophys. Res., 99 (C12), 24487-24504, 1994.
Mitchum, Gary T., 1998: Monitoring the stability of satellite altimeters with tide gauges. J. Atmos. And Oceanic
Tech, 15,721-730.
Spencer N.E. and P.L. Woddworth, 1993. Data holdings of the Permanent Service for Mean Sea Level. Bidston,
Birkenhead: PSMSL. 81 pp.
Testut, L., P. Téchiné. Correction des données de Pression Atmosphérique du capteur ORION de la station de
Kerguelen. Rapport Interne, Dec. 2002.
,
Woodworth P. L., C. Le Provost, L.J. Rickards, G.T. Mitchum, M. Merrifield, A Review of Sea-Level Research
from Tide Gauges during the World Ocean Circulation Experiment, Oceanography and Marine Biology: an
Annual Review, Vol. 40, 1-35, 2002.
Woppelmann G., Localisation par technique GPS des stations d’observation du niveau de la mer du réseau
WOCE, thèse de doctorat de l’Observatoire de Paris, Juin 1997.
Yoon H.J., Les variations du niveau de la mer sur la région d' Amsterdam
- Crozet-Kerguelen, thèse de
l' Université de Grenoble, Mai 199
7.
16
MANAGEMENT PLAN AND COST
V.1 Management Plan
WP1: Design a high standard tide gauge network
Task1.1 Upgrade and manage the network
Task 1.2 Quality Control and data distribution
Indian
Austral
Pacific
Atlantic
Mediter.
All
LT
All
All
CCA
LC
Mediter
GJ
GJ
LT
FL
FL
Indian
All
LT
LT
External
Collaboration
Internal
Collaboration
Leader
External Collaborators
HYP : H.Y. Park (Museum)
CKS : C.K. Shum (OSU)
KS: K. Sheng (OSU)
MNB: M.N. Bouin (IGN)
FB: F. Boldo(IGN)
GPG:G.P. Gasparini (ENEA)
PB: P. Bonnefond (CERGA)
Working Site
Internal Collaborators
PDM: P. De Mey
RM : R. Morrow
CLP: C. Le Provost
PM: P. Marsleix
LR: L. Roblou
Work Package
N°
Work Package Leader
LT: Laurent Testut
SC: Stéphane Calmant
GJ: Gwenaele Jan
FL: Florent Lyard
MNB
FB
CKS
KS
SC
FL
LT
LR
CLP
WP2: Scientific cross-verification experiments
Task 2.1 Validation of coastal altimetric products
Task 2.2 Extension to Altimetric Multi-Missions
Task 2.3 Transport variability calculation
Task 2.4 Numerical ocean models for coastal and off-shore ocean
dynamic connection
WP3: Coordination and Synthesis
RM
RM
RM
PM
PDM
LR
LT
FL
All
PB
HYP
GPG
HYP
All
17
V.2 Cost Plan
Labour Costs:
• 12 months of CDD for Extension to Altimetric Multi-Missions (task2.2)
2004:
-
-
Equipment for WP1
o Radar sensor for Kerguelen calibration test
o Second sensor for Macinaggio
o Meteorological station for Macinaggio
Linux station for modelling
15 Ke
15 Ke
10 Ke
2 Ke
Equipment for WP1
o Complete station for Clipperton
30 Ke
Equipement for WP1
o Updating of Saint-Paul Station
o GPS buoy deployement SP&Kerguelen
15 Ke
10 Ke
Equipemnt for WP1
o Updating Dumont d’Urville station
15 Ke
2005:
-
2006:
-
2007:
-
WP3 Costs
- Travels/year:
Participation to SWT
2 scientific meetings (AGU -EGS)
Travel for external collaborators
- Publications/year:
WP1
WP2
WP3
TOTAL
2004
40 Ke
2 Ke
10 Ke
52 Ke
3.5 Ke
3.0 Ke
2.0 Ke
1.5 Ke______
10 Ke / year
2005
30 Ke
2006
25 Ke
2007
15 Ke
10 Ke
40 Ke
10 Ke
35 Ke
10 Ke
25 Ke
18
Laurent TESTUT
20/09/1971 Paris
LEGOS/GRGS, 18 Av. Edouard Belin, 31055 TOULOUSE CEDEX France
Tel: (33) 5.61.33.27.85
Fax: (33) 5.61.25.32.05
e-mail: [email protected]
Education:
1996: DEA (equivalent to Master’s Degree) in Oceanography and Meteorology at the
Paul Sabatier University, Toulouse, France
2000 : Ph-D Thesis on altimetry above ice sheet « l’apport de l’altimétrie à l’étude des
calottes polaires » , University of Toulouse.
2001 : CNES Post-doc on ocean dynamic, Legos, Toulouse
Present Position
Physicien Adjoint at LEGOS
Research Topics :
Ice sheet dynamics and long term sea level variation
South Indian ocean dynamic
Altimetric and tide gauge sea level measurements
Courses:
Since 1997: Courses at Toulouse University
Scientific Responsibilities
In charge of the ROSAME tide gauge network
Member of the Antarctic GDR
Menber of the Scientific Board of Observatoire Midi-Pyrennes
Publications
[1] Testut L., I.E Tabacco and F. Rémy, 2000: Influence of precise geometrical boundary
conditions on the estimation of rheological parameters. Ann. of Glaciol., n°30,p102-106.
[2] F. Rémy, L. Testut et B. Legrésy, 2000. Topographie des calottes polaires par altimétrie
satellite. Comptes Rendus de l’Académie des Sciences, 330, p457-467.
[3] F. Rémy, B. Legrésy and L. Testut, 2001. Ice sheet and satellite altimetry. Survey in
Geophysics, 22, p1-29.
[4] M.B. Lyhte, D. Vaughan, and the BEDMAP Consortium. 2001. BEDMAP : A new ice
thickness and subglacial topographic model of Antarctica. Journ. of Geophys. Res. Vol 106.
N°B6, p11,335-11351.
[5] F. Rémy, L. Testut and B. Legresy. 2001. Random fluctuations of snow accumulation
over Antarctica and its relation with sea level change. Clim. Dyn. 19, p267-276.
[6] J-J. Peucat, R. Capdevila, M.C. Fanning, L. Pecora, R.P. Ménot and L. Testut. 2001.
1.60-Ga-old felsic volcanic blocks in moraines of the Terre Adélie Craton, Antarctica
compared with South Australian igneous province: Petrographical, geochemical and
geochronological evidence. Australian Journal of Earth Science.
[7] Testut L., R. Hurd, R. Coleman, F. Rémy and B. Legrésy 2002. Comparison between
computed balance velocities and GPS measurements in the Lambert Glacier Basin. Accepted
Ann. Of Glacio.
[8] F. Rémy, L. Testut, B. Legrésy, A. Forieri, C. Bianchi and I. Tabacco 2002. Lakes and
subglacial hydrological networks around Dome C and their impact on ice flow. Accepted Ann.
Of Glacio.
[9] Aman A., L. Testut, S. Arnault, G. Eldin, Y. du Penhoat, B. Bourles and P. Téchine.
2003. Seasonal upwelling in the Gulf of Guinea from altimetry and tide gauge. In prep
19
Gwénaële JAN
Employer
NOVELTIS
Scientific Engineer, Dr.
Current Position
Proposed
project
position
Academic Qualifications
Thesis (PHD) : Physical oceanography and numerical modelling at LODYC (Laboratoire
d'Océanographie DYnamique et de Climatologie, University of Paris 6, France) 2001.
European Master degree (ERASMUS program) in oceanography and marine environment
modelling. University of Liege (Belgium), Physics department. And Master degree in
Oceanography-Meteorology-Environment, University of Paris 6 (France). Year1995-1996.
Relevant Experience
Modelling the impact of the Air-Sea interaction in the upper ocean
layers in the Mediterranean Sea (CNRS:National Research Center
and the French Meteorology Office)
Coastal ocean circulation. Collaboration with the laboratoire
d’aérologie (CNRS)
Altimetry applied to the ocean : Absolute calibration of a radar
altimeter (CNES). Use of tide gauges measurements.
Career History and Key experience
2001-2003
Scientific Engineer Dr in oceanography at Noveltis
Absolute calibration of the radar altimeter POSEIDON-2, on board
on the JASON-1 satellite (CNES)
Coastal 3D ocean circulation and use of a 2D gravity waves model.
Laboratoire d’aérologie and LEGOS. (CNRS, Toulouse)
1997-2001
PHD degree: Modelling the impact of the high frequency
atmospheric forcing in the upper layers of the Mediterranean Sea.
Partners: French Met Office and University Paris 6, France.
Technical knowledge
Science
Technical knowledge in oceanography:
Marine environment modelization.
Technical knowledge in altimetry:
Characterisation of the oceanic processes.
Absolute calibration of a radar altimeter.
Management, communications
1998
1993
Co-Manager of an engineers’ group from the National school of
Meteorology. Black Sea modelling.
Lecturer for the Study Centre and Valorisation of seaweeds.
Theme : The use and valorisation of the seaweeds in industry, on
the Brittany coast. (CEVA, France). Summer work.
Publications
[1] Drift Modeling of Cargo Containers. P.Daniel, G.Jan, F.Cabioc'h, Y.Landau and E.Loiseau. Spill
Science & Technology Bulletin. Vol 7.n05-6,pp279-288,2002.
[2] Lipid chemistry of particule and dissolved organic matter in the North Adriatic in september 1994
and june 1995. Soumis à EC Ecosystems research reports series - the Adriatic Sea - june, 4, 1996.
Derieux S., Moine.F, Fillaux.J, Pinturier.L., Jan G., Laureillard J., Saliot A.
[3] Réponse des couches de la surface océanique aux forçages atmosphériques avec un modèle à haute
résolution verticale. Application à la mer Méditerranée. Doctorat de l’Université Pierre et Marie
Curie, soutenu le 27 mars 2001.
20
Stéphane Calmant,
PhD in Oct 1987
HDR in Oct 2001
Dir de Recherche IRD (since Jan 2002) at LEGOS
Author/co-author of ~30 publications in peer-referred journals on the following topics:
- seafloor structure and bathymetry using satellite altimetry
- Tecto-geodesy and crustal deformations (co-seismic, inter-seismic) using space geodesy
(GPS)
- altimetry validation from Tide Gauges (PI JASON for the MOTEVAS Project)
- Continental waters from altimetry
Member of the National Commission for Geosciences (formely IFREMER Commission)
refeering/planning the cruises onboard the French research Vessels
Member of the Scientific Commitee of the Geophysical Observatories of IRD
21
Florent Lyard
Employer
CNRS
Current Position
Senior Researcher, CR1
[email protected]
E-mail
Academic Qualifications
PhD Fluid Mechanics, “Tidal Hydrodynamic Modelling: application to
ocean”, Université Joseph Fourier, Grenoble, 1992
Relevant Experience
the Indian
Gravity waves, storm surges and tidal dynamic
Inverse methods, ensemble and variational assimilation technique
in oceanography
Sea level data analysis
Finite elements and volumes hydrodynamic modelling
Numerical models and computational techniques
Career History and Key experience
Since October 1997
Senior researcher at LEGOS (Toulouse)
Development of hydrodynamic and assimilation models for global,
regional and coastal applications
In situ and satellite altimer data treatment and analysis
Co-manager of the “Pôle d’Océanographie Côtière de l’OMP”
Co-investigtor in several european and national oceanographic
projects
1993-1997
Post doctoral position
Tidal modelling (LEGI, Grenoble, France)
Data assimilation (POL, Bidston, UK)
Long period tides modelling (GFZ, Postdam, ,Germany)
Technical knowledge
Data inversion and assimilation
Finite element, finite volumes modelling
Data processing
Numerical development
22