OCCAM and CANIGO

Members of the Ocean Circulation and Climate Advanced Modelling project (OCCAM) are participating in the European MAST II project concentrating on the CANary Islands Azores and Gibraltar (Observations) region ( CANIGO).

OCCAM's main interest is in developing a stream-tube parameterisation of the Gibraltar overflow in order to improve the representation of Mediterranean Water in large-scale, global, general circulation models (sub-project task 4.3.5.1).

New: Portable Document Format (PDF) versions of posters covering aspects of the OCCAM model are now available from our posters page. Two of these have been prepared explicitly for CANIGO meetings:

Models of the Mediterranean Outflow (0.5MB). Presented at the CANIGO sub-project 4 meeting, Madrid November 1997

The Mediterranean Outflow in the OCCAM model (2MB). Presented at EGS'98 Nice.

Another, covering work of interest to CANIGO was presented at 1998 World Ocean Circulation Experiment (WOCE) conference :

On the Connection between the Gibraltar Throughflow and the Azores Current (2.5MB)

Traditionally, z-coordinate, primitive equation models (such as OCCAM) incorporate a crude approximation to convective mixing events. This, together with a poor spatial resolution dictated by insufficent computing power, often results in a tendency to "over-mix" the dense overflow waters. This, in turn, often results in a failure of global circulation models to correctly model the formation of the important deep water masses.

That said, the current OCCAM global model successfully reproduces many of the general physical features of the CANIGO area. The OCCAM model has been integrated for 14 model years (starting from Levitus climatology) and is forced, at the surface, with monthly climatologies.

Several physical features which were initially poorly represented by the model (such as the position of the Azores current) have continued to improve during the model integration. Although still far from an accurate representation of the highly chaotic state of the real ocean, it is hoped that the current model is sufficiently realistic to provide some insight into the complex physical oceanography of the CANIGO area. In particular, the temporal variation in the area can be appreciated with reference to animations of the model results.

Three such animations are available from this page and each may be viewed by selecting one of the following thumbnail images. Each sequence is an MPEG "movie" (approx. 1.2MB) showing the model salinity at one of three selected vertical levels:

 Level 9: 245m     Level 15: 716m    Level 18: 1150m

Higher resolution stills (15KB) of the first frame in each sequence may be obtained by clicking on the appropriate blue button.

A mpeg-movie of the sea surface height is also available. This animation shows the sea surface height with one frame every six model days (starting at day 3202 (October year 8)). The colour scale used ranges from -65.cm (blue) through to +30.cm (red).

Anyone interested in obtaining further results from the OCCAM model, either within the CANIGO area or anywhere else in the world, is welcome to contact any member of the OCCAM team listed below.