Black Sea Forecasting System: Current State and Prospect

Abstract

An operational system permitting nowcasting and forecasting of the real-time Black Sea circulation and surface wave dynamics is presented. The system is based on the regional atmospheric model with 24 km grid step, primitive equation model of the Black Sea circulation with 5 km grid step, WAM model of the surface waves coupled with circulation model with the same spatial resolution, and the set of local circulation models with resolution 1 km nested near the coast of riparian countries. An important part of the operational system is assimilation of space remote sensing data including sea surface height anomalies provided in near real time mode, a multi-satellite data active archive dedicated to space oceanography, and surface temperature. The output of the system includes near surface meteorology (10 m wind, latent and sensible heat flux, cumulated solar and thermal radiation flux, instantaneous flux of solar and thermal radiation, eva- poration, large scale and convective precipitation), three dimensional hydrophysical fields (temperature, salinity, current velocities), surface chlorophyll concentration, and surface wave characteristics. Data from surface drifting buoys and deep profiling floats are used for validation of the model output. Surface drifting buoys provide data for validation of surface current velocity and sea surface temperature. Eight profiling floats deployed at the parking depths 200, 750 and 1,550 m are used for validation of weekly mean velocity, temperature and salinity profiles. The model validation shows that the real time products of the system have reasonable accuracy. The regional weather prediction model implemented by National Meteorological Administration of Romania and marine basin-scale nowcasing/ forecasting system provides good basis for the development of operational nowcast and forecast of coastal dynamics with high spatial resolution. Ongoing national initiatives concerning oceanographic modeling of the most important regions along the Black Sea coast are considered as the base of the nesting strategy development in the basin. Regional POM models near Bulgarian, Turkish, Georgian, Romanian, Russian and Ukrainian coasts are nested to the basin-scale circulation model of MHI. Every model specifies open boundary conditions from the basin-scale circulation model. The Black Sea observing/forecasting system is applied for the hindcast of the long-term evolution of the Sea fields. Evidence of the decadal evolution of the stratification and circulation is presented by the system output. Two more examples demonstrate the extreme events in the coastal