Analysis systems for the mesoscale thermal variability in the Greenland-Iceland-Norwegian Sea
Mesoscale thermal structure and its spatial variability are very significant for acoustic propagation in the ocean. Therefore ocean thermal analysis procedures are important for the initialisation andverification of environmental and acoustical models. This study involved the implementation of software, and the production, from irregularly-spaced data, of uniformly-gridded temperature fields for use by numerical acoustical and environmental models. The two analyses, considered for the production of temperature fields are: (1) an objective analysis method based on the Gauss-Markov Theorem which makes use of additional information such as climatology (the Levitus climatology has been used in this study), and (2) an interpolation method based on contouring techniques provided by the UNIRAS graphics package. Data from the Summer '86 cruise in the Greenland-Iceland-Norwegian Sea of the Applied Oceanography Group of SACLANTCEN are used to demonstrate the methods. Both methods agree well when there isa high density of data. When the data availability is limited, there is a danger that the objective analysis method can give rise to spurious gradients in going from the regime dominated by data to that dominated by climatology. Whether this is less desirable than a field based on extrapolation from a few observational data points depends on the application.