2009 Issue №1

The article examines the results of use of the physical-statistical method for the forecast of seasonal trend of the sea surface temperature (SST) with the lead time of 8 months and results of statistical method of SST superlong-term forecast, lead time — 1 year. In the first case mean-squared prediction error of SST according to independent data makes 0,5 оС, in the second case — 0,2 оС, that is much less than the reasonable mistake and meets practical requirements.

The article examines some features of the upwelling observed in the South-East Baltic in October 2005 which were investigated by
means of comparison of the field measurement data and numerical simulated data. The article explores the upwelling which took place after calm weather when thermohaline fields had parameters close to summer ones. Upwelling was produced by North-East wind with sped of about 15 m/s and duration of about 3 days. After the gale the alongshore belt of respectively cold water of width 8 km and placed apart the shore at 8 km had been formed in an area with depth of 25 m. The temperature in the upwelling core had dropped by 4 C. Changes in thermoholine structure due to the gale were simulated by 3D numerical model, based on the Princeton Ocean Model (POM). By means of numerical simulation it was conformed that features of upwelling space structure depend upon bottom topography in an area of observation, strength of wind velocity and its duration. The dependence of the
upwelling scenario on the Froude number was obtained.

The article provides the example of an evaluation of thermal conductivity in vertical direction under the data of field observations in
the coastal waters of Sambia peninsula is considered. The calculation of volume absorption of solar radiation is made.

The article shows that the water dynamics induced by differential cooling in upper shelf area (down to 60 m depth) is significantly influenced by day/night variations which delays an establishing of a seasonal water-exchange in shallows. Convective exchange flows within the entire shelf region in seasonal circle requires 4—7 weeks to reach a quasisteady state. Formation of a linear portion on the horizontal temperature profile can be used as an indicator of the approaching of the flow to the steady state. Flushing time for the shelf zone under steady-state condition is 30 days and is only slightly influenced by the slope length.

As it is known [1], the variability of ocean’s natural objects is concentrated in relatively small boundary zones of transforming of
matter and energy. These active surfaces, where the leap in process’s features take place, are also known as barrier zones. These zones, which were thoroughly investigated for oceans and open seas, are not examined well enough for internal seas. More over, the very definition of the «barrier zones» which is close to the definition of «water mass» in classic hydrology doesn’t always indicate their existence at all. This paper presents an attempt of applying formal methods for zoning and of comparing the results with classic barrier zone definitions.