retish
9th March 2005, 11:40 AM
Applications are invited for a 3-year post-doctoral fellowship at LOCEAN (formerly known as LODYC, and located in Paris), starting from the month of March onward. The successful candidate will work on validating and improving an existing 4D-Var assimilation system for a global ocean model, in a project funded by the French space agency (CNES).
Advanced data assimilation method that take into account the model dynamics (like 4D-Var or Kalman filtering) can provide estimates of the ocean state which are both compatible with observations and the physical laws governing the oceanic flow. These improved estimates of the ocean state can be beneficial both to operational applications (e.g. seasonal forecasting) and to research (by helping to generate long consistent re-analyses of the ocean circulation).
Over the last few years, an incremental 4D-Var data assimilation system has been developed for the OPA ocean general circulation model (eg Weaver et al., 2003; Vialard et al., 2003) as the result of collaboration between CERFACS (Toulouse, France) and LODYC (Paris, France). This system was initially developed for assimilating potential temperature profiles into a tropical Pacific version of the OPA OGCM. It has recently been upgraded for assimilating altimeter data into a global ocean model. The system is now at a mature technical development stage, and preliminary re-analyses assimilating T/P data have been produced for the 1993-2001 period. Preliminary assessment of this experiment is encouraging, but also suggests some necessary developments. The main tasks that the successful candidate will undertake are the following:
- Calibration of the parameters of the system
- Production and evaluation of improved long re-analyses assimilating altimeter data
- Understanding the dynamics of error correction in the system
- Upgrading of the system to assimilation of other altimeter products (ERS1 and 2, Jason)
- Investigation of assimilation of sea surface temperature satellite products
- Investigation of assimilation of sea surface salinity satellite products in view of SMOS and Aquarius
The candidate will be based in LOCEAN (Paris) but will frequently work with the team of Anthony Weaver (CERFACS, Toulouse).
The position is for three years and can be filled from the month of March onward. Monthly net income is about 1500 €.
The candidate would preferably have a background in physical oceanography or atmospheric sciences and in data assimilation. Good knowledge of Unix and Fortran is required, and experience with supercomputers would be welcome.
Interested candidates should get in touch with Jérôme Vialard ( jv@lodyc.jussieu.fr ).
A few references using the data assimilation system are given below:
Vialard, J., A.T. Weaver, D.L.T. Anderson and P. Delecluse, 2003: Three- and four-dimensional variational assimilation with a general circulation model of the tropical Pacific Ocean, Part 2*: physical validation. Monthly Weather Review, 131, 1379-1395.
Weaver, A.T., J. Vialard, and D.L.T. Anderson, 2003: Three- and four-dimensional variational assimilation with a general circulation model of the tropical Pacific Ocean, Part 1*: formulation, internal diagnostics and consistency checks. Monthly Weather Review, 131, 1360-1378.
Vossepoel, F., A.T. Weaver, J. Vialard and P. Delecluse, 2004, Adjustment of near-equatorial wind stress with four-dimensional variational data assimilation in a model of the Pacific Ocean, Mon. Wea. Rev, 132, 2070-2083.
Ricci, S., A.T. Weaver, J. Vialard and P. Rogel, 2005, Incorporating state-dependent Temperature-Salinity constraints in the background error covariance of variational ocean data assimilation. Mon. Wea. Rev., 133, 317-338.
Moore, A., J. Vialard, A.T. Weaver, D.L.T Anderson, R. Kleeman and J.R. Johnson, 2003 : The role of air-sea interaction in controlling the optimal perturbations of low-frequency ocean atmosphere modes, Journal of Climate, 16, 951-968.
Jérôme Vialard
Laboratoire d'Océanographie DYnamique et de Climatologie
LODYC - Case 100 - UPMC jv@lodyc.jussieu.fr
4, Place Jussieu Tel: +33 1 44 27 70 74
75252 Paris Cedex 05 - France Fax: +33 1 44 27 38 05
Advanced data assimilation method that take into account the model dynamics (like 4D-Var or Kalman filtering) can provide estimates of the ocean state which are both compatible with observations and the physical laws governing the oceanic flow. These improved estimates of the ocean state can be beneficial both to operational applications (e.g. seasonal forecasting) and to research (by helping to generate long consistent re-analyses of the ocean circulation).
Over the last few years, an incremental 4D-Var data assimilation system has been developed for the OPA ocean general circulation model (eg Weaver et al., 2003; Vialard et al., 2003) as the result of collaboration between CERFACS (Toulouse, France) and LODYC (Paris, France). This system was initially developed for assimilating potential temperature profiles into a tropical Pacific version of the OPA OGCM. It has recently been upgraded for assimilating altimeter data into a global ocean model. The system is now at a mature technical development stage, and preliminary re-analyses assimilating T/P data have been produced for the 1993-2001 period. Preliminary assessment of this experiment is encouraging, but also suggests some necessary developments. The main tasks that the successful candidate will undertake are the following:
- Calibration of the parameters of the system
- Production and evaluation of improved long re-analyses assimilating altimeter data
- Understanding the dynamics of error correction in the system
- Upgrading of the system to assimilation of other altimeter products (ERS1 and 2, Jason)
- Investigation of assimilation of sea surface temperature satellite products
- Investigation of assimilation of sea surface salinity satellite products in view of SMOS and Aquarius
The candidate will be based in LOCEAN (Paris) but will frequently work with the team of Anthony Weaver (CERFACS, Toulouse).
The position is for three years and can be filled from the month of March onward. Monthly net income is about 1500 €.
The candidate would preferably have a background in physical oceanography or atmospheric sciences and in data assimilation. Good knowledge of Unix and Fortran is required, and experience with supercomputers would be welcome.
Interested candidates should get in touch with Jérôme Vialard ( jv@lodyc.jussieu.fr ).
A few references using the data assimilation system are given below:
Vialard, J., A.T. Weaver, D.L.T. Anderson and P. Delecluse, 2003: Three- and four-dimensional variational assimilation with a general circulation model of the tropical Pacific Ocean, Part 2*: physical validation. Monthly Weather Review, 131, 1379-1395.
Weaver, A.T., J. Vialard, and D.L.T. Anderson, 2003: Three- and four-dimensional variational assimilation with a general circulation model of the tropical Pacific Ocean, Part 1*: formulation, internal diagnostics and consistency checks. Monthly Weather Review, 131, 1360-1378.
Vossepoel, F., A.T. Weaver, J. Vialard and P. Delecluse, 2004, Adjustment of near-equatorial wind stress with four-dimensional variational data assimilation in a model of the Pacific Ocean, Mon. Wea. Rev, 132, 2070-2083.
Ricci, S., A.T. Weaver, J. Vialard and P. Rogel, 2005, Incorporating state-dependent Temperature-Salinity constraints in the background error covariance of variational ocean data assimilation. Mon. Wea. Rev., 133, 317-338.
Moore, A., J. Vialard, A.T. Weaver, D.L.T Anderson, R. Kleeman and J.R. Johnson, 2003 : The role of air-sea interaction in controlling the optimal perturbations of low-frequency ocean atmosphere modes, Journal of Climate, 16, 951-968.
Jérôme Vialard
Laboratoire d'Océanographie DYnamique et de Climatologie
LODYC - Case 100 - UPMC jv@lodyc.jussieu.fr
4, Place Jussieu Tel: +33 1 44 27 70 74
75252 Paris Cedex 05 - France Fax: +33 1 44 27 38 05