1980 - National Institute of Oceanography

2. the integral mean concentration of the nutrients in the surface mixed layer
is in agreement with the near-surface circulation. The high value of nutrients associated
with low dissolved oxygen are confined to thicker surface layers indicating
clearly the effect of divergence or cyclonic gyre (convergence or anticyclone gyre)
present in the near-surface circulation.
3. the salinity structure shows that the Bay of Bengal has estuarine type of
circulation due to heavy discharge of fresh water all along its land peripheries.
(c) ΜΟΝΕΧ-79 studies
The hydrographic and MBT data collected during MONEX-79 programme
were processed. For the analysis of these data, the following computer programmes
were developed: (i) Bionomial filter programme for smoothening the digitized data,
(ii) A programme for computing the potential energy of the water column and the
energy changes due to mixing and (iii) A programme for analysing the wave
records.
The study revealed significant variations in the upper 500 m during the period
May to June 1979. The sea surface temperature increases by about 1°C whereas
the thickness of the mixed surface layer decreases by about 10 m. Inspite of the
above features, the cyclone heat potential showed an increase from May to June
1979 in the MONEX square (the region from where the data were collected). The
heat potential was estimated to be about 30 kcal/cm 2 which can maintain a moderate
cyclone for a period of 6 days. The rise in thermocline is attributed to the entrainment
of cool subsurface water into the surface layer. Further studies to prove
this are being carried out using the continuity equation. The influence of equatorial
watermass in the MONEX area is clearly seen during May-June 1979.
Preliminary studies on the thermodynamic potential of seawater indicated that the
changes in energy associated with contraction or mixing are important for understanding
the watermass structure in the MONEX square.
(d) Heat budget of the Andaman Sea
The seasonal heat storage including the fluxes of net radiation, latent and sensible
heat have been worked out for the Andaman Sea. These studies indicated an
annual evaporation rate of about 137 cm over the region of the Andaman Sea and the
vertical heat transport is confined to the upper 20 m where a strong halocline exists
which probably inhibits the heat transfer to deeper waters.
3.1.2 Studies on physical processes in the seas around India
Field data were collected during 7 cruises from the Bay of Bengal including
the Andaman Sea and the eastern Arabian Sea. During two of these cruises (viz-
69th and 75th) observations were carried out in the MONEX square for studying
the post-monsoon conditions. CSTD System was operated and continuous profiles
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