ASSESSING THE IMPACT OF THE PLANNED APPROACH CHANNEL TO THE SEAPORT SABETTA ON SALINITY CHANGES IN THE GULF OF OB

摘要

The assessment is made of the changes in the salt regime near the channel projected in the northern part of the Gulf of Ob that can be caused by topography change due to the construction of the approach channel to the seaport Sabetta. Since the full-scale experiment is not possible in this case, the only way to solve this problem is performing experiments on the salt regime sensitivity to the topography change with using numerical modelling. For this purpose, we use the well-proved Russian universal σ-model of ocean and sea circulation INMOM (Institute of Numerical Mathematics Ocean Model), developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences. This model is implemented to simulate the circulation of the Kara and Pechora Seas. Its global version is used in the framework of international projects CORE (Coordinated Ocean-ice Reference Experiments) and CMIP (Coupled Model Intercomparison Project). The experiments conducted in the Gulf of Ob show us that the strongest annual mean salinity growth due to the presence of the channel occurs near this channel and reaches 0.45 PSU in absolute or 4.5% in relative. While moving away the channel one can see a significant reduction of its impact. The natural interannual salinity variability is revealed in the water area under research (RMS is about 2÷3 PSU, variability is up to 8 PSU), which depends on both river runoff variability and atmospheric forcing. At the same time, using the results of numerical simulations, it was obtained that the natural interannual salinity variability is much higher than its change caused by the presence of the approach channel.