### ASA 127th Meeting M.I.T. 1994 June 6-10

## 2pUW5. State estimation using ATOC measurements: A numerical study.

**Dimitris Menemenlis
**

**
Carl Wunsch
**

**
**
*Earth, Atmospheric and Planetary Sci., MIT, Rm. 54-1524, Cambridge, MA
02139
*

*
*
A numerical study carried out in anticipation of acoustic thermometry of
ocean climate (ATOC) measurements is described. The aim of the study is to
combine long-range tomographic measurements with numerical models and other a
priori information in order to improve the ocean state estimate. A 4-yr
integration of the Semtner and Chervin general circulation model is assumed to
represent the real ocean. The integration was performed with a nominal
resolution of a 1/4 deg in the horizontal and 20 layers in the vertical.
Sound-speed profiles along the proposed North Pacific ATOC paths in conjunction
with canonical spectra for the scales not resolved by the model are used to
generate simulated tomographic data. The estimation problem is addressed using
a lower resolution primitive-equation model of the North Pacific. The second
model is assumed sufficiently realistic that perturbations from the Semtner and
Chervin ocean may be treated as linear. A time-independent state transition
matrix is computed for large-scale density anomalies about the mean of the
second model. The estimation problem is then solved using a Kalman filter and
the resulting state estimate is compared with the Semtner and Chervin ocean.