Project Co-Directors:

Josef Cherniawsky, Institute of Ocean Sciences, Sidney, B.C., Canada (NPD)
Evgueni Kulikov, Shirshov Institute of Oceanology, Moscow, Russian Federation (PPD)
Aleksander Toompuu, Marine Systems Institute, Tallinn, Estonia
Konstantin Klevanyy, Russian State Hydrometeorological University, Saint Petersburg, Russian Federation
Oleg Nikitin, State Oceanographic Institute, Moscow, Russian Federation

Approval Date:	15.11.2005	Effective Date:	01.10.2006
Duration:	3 years

Abstract of Research

This research is focused on gaining scientific understanding and improving quantitative predictions of extreme sea-level events in the Baltic Sea and the Gulf of Finland. The most intensive sea-level oscillations in the Baltic Sea and most severe floods occur in the Eastern Gulf of Finland (EGF), as storm winds over the Baltic Sea drive large volumes of water into the shallow Neva Bay at the head of the Gulf. A major objective of the project is development of a reliable system for prediction of sea-level variations and storm surges along the EGF coast.

Major Objectives

• to develop statistical models for the analysis of sea-level data in the Baltic Sea;
• to carry out analyses of interannual variability of sea level in the Baltic Sea on the basis of available coastal and altimetry data and the developed models;
• to perform statistical and numerical model studies of sea-level extremes and their relation to the natural variability and anthropogenic influence;
• to assess the risk of short-term (catastrophic) flooding;
• to examine the long-term trends in sea level in the Gulf of Finland, in view of gradual flooding and sinking of its shores;
• to study water quality in the Neva Bay with a new refined model of the Neva Bay and EGF, with inclusion of the newly constructed St. Petersburg Flood Protection Barrier;
• to improve the accuracy of the operational Flood Forecasting System for St. Petersburg by re-validation and introduction of data assimilation methods;
• to carry out numerical experiments to study the characteristics of water motion in the Baltic Sea, to uncover the predominant flood-generating mechanisms, such as wind-drift, or long-wave propagation;
• to assess contributions to sea-level rise from various natural factors, based on numerical experiments with specified scenarios;
• to modernize the Baltic Sea level information systems.

Overview of Achievements since the Start of the Project until 20 April 2009

• Numerical experiments with a flood forecasting model of EGF. Numerical model studies of the effect of advective non-linear terms on sea-level oscillations in the Gulf of Finland.
• Increase in the accuracy of Operational Flood Forecasting system for St.Petersburg: 1) a change to more refined grid in the Baltic Sea model BSM6, 2) an increase in the frequency of delivery of atmospheric forecasts from one to two times per day, and 3) assimilation of observed water level data from the Gornii Institute station.
• Evaluation of forecasts of extreme water levels in the Gulf of Finland and in the Gulf of Riga with the Baltic Sea models BSM5 and BSM6.
• Studies of the structure of storm surges in the Gulf of Finland, including contributions from long and standing waves, relative influence of wind stress and atmospheric pressure gradients, and theoretical verification of the effects of resonance for an idealized channel domain.
• Development of the Neva Bay model for the modern state of the Flood Protection Barrier. Numerical experiments aimed to estimate the suspended sediment loads in the Bay in its present state.
• Statistical analysis of multi-year time series of coastal sea-level observations along the south coast of the Gulf of Finland. Estimation of extreme sea-level recurrence for locations of the Gulf of Finland. Study of variations of multiyear sea level trends along the coast of the Gulf of Finland.
• Preparation of satellite altimetry-data archive and analysis of data quality for the Baltic Sea from Jason-1, Envisat, GFO, ERS-1, ERS-2, TOPEX/POSEIDON and GEOSAT satellites. Examination of time and spatial coverage of altimetry data and initial analyses of sea-level extremes.
• Marine experiments for deployment and testing of new tide gauges. Installation of automatically working tide gauge complex in the bay of the Gogland Island in the Gulf of Finland for operative work.
• Geodetic leveling of benchmarks for marine sea-level gauges in the Gulf of Finland.
• Compilation and digitization of historical sea-level data for the Eastern Baltic. Creation of relational databases of sea-level observations and of benchmarks for sea-level gauges.
• Study of variations of multiyear sea level trends along the coast of the Gulf of Finland.
• Development of a wind-driven version of the Princeton Ocean Model for the Baltic Sea with high horizontal resolution and with wind forcing changing randomly in time, allowing to study resonant sea-level response and seiche modes in the Baltic Sea. Study of the relative roles of forcing fields (pressure, wind) in forming the floods.
• Identification of a clear spectral peak with a period of 27 hours in the observed sea-level spectra, which is a well-known resonant mode in the Gulf of Finland. Study of a resonant mechanism producing extreme sea-level events with a relatively high Q-factor (Q ~ 4).

Milestones for the Next Six Months

Evaluation of extreme water levels along the EGF:

• Finalization of evaluations of extreme water levels in the Gulf of Finland and in the Gulf of Riga from coastal stations and altimetry data.

Development and modernization of Operational Flood Forecasting System for St. Petersburg:

• Increase in the frequency of forecasts from two to four times per day.
• Improvements in operational flood forecasting by testing and implementation of new data assimilation methodologies.
• Simulations of the Neva Bay and EGF with new refined model, aimed to investigate changes in water quality in this area after completion of the St. Petersburg Flood Protection Barrier and comparison of these results with those obtained for natural conditions without a barrier.

Stochastic/numerical modelling and flood risk estimation:

• Continuing development and testing of the Baltic Sea numerical model for long-term simulations of sea-level variations and storm surges generated by winds and atmospheric pressure disturbances, which also allow us to study the effects of basin resonance and of varying atmospheric forcing.

Evaluation of extreme water levels along the EGF:

• Statistical analysis of sea-level extremes and estimation of flood recurrence intervals for different locations in the Gulf of Finland. Analyses of resonant mechanisms contributing to flooding events.

Modernization of the Baltic sea-level information system

• Continuation of digitization and editing of historical sea-level data in the archive of the State Oceanographic Institute.
• Continuation of improvement and tests of the tide-gauge complex in Gelendzhik.
• Developing of software for magnifying of completeness and reliability of information transmitted from the tide gauge complex at the Gogland Island to a coastal server in St. Petersburg.
• Expedition to the Gogland Island. Prophylactic works with the tide-gauge complex, cleaning of submerged sensors, replacement of a battery. Possible change of sensors and electronic module in the input unit of the complex according to results of tests of the complex in Gelendzhik. Installation of a lightning rod near to a complex as a defense from hits of lightnings during thunder-storms.

Processing and statistical analysis of altimetry data in the Baltic Sea:

• Statistical analyses of sea-level data from satellite altimetry data and comparisons with coastal observations and with numerical model results.

Consultation with end-users:

• As needed and related to a new sea-level station at Gogland Island, geodetic leveling of benchmark coordinates along the Russian coast of the Gulf of Finland and information data base and data products.

Workshops and conferences:

• Presentation of the project scientific results at the International Workshop on Flood Vulnerability and Flood Protection in Tidal and Non-Tidal Regimes:North and Baltic Seas, Delft, The Netherlands, April 27-29, 2009.

Internet site development and support:

• Updating and continuous development of the project Internet site.

Implementation of the Results:

A graphical interface for visualization of observational data at the Gogland Island was developed and handled to the end-user (St. Petersburg Center for Hydrometeorology and Environmental Monitoring). Since July, 19 of 2008 these data have been transmitting in numerical form from the tide gauge complex (installed by the project participants) by cellular communication to coastal computers of the end-user in Saint Petersburg.

NATO Consultant:

Dr. Herman Gerritsen, WL/Delft Hydraulics, Delft, NL

Other Collaborating Institutions:

1. Mass & Heat Transfer Institute, Minsk, Belarus,
2. Russian National Oceanographic Data Centre, Obninsk, Russian Federation,
3. F.N. Krasovsky Central Research Institute of Geodesy, Moscow, Russian Federation,
4. Central Design Bureau of Hydrometeorological Instrumentation, Obninsk, Russian Federation,
5. St. Petersburg State University, St. Petersburg, Russian Federation,
6. Flood Defense Department of St. Petersburg Government, St. Petersburg, Russian Federation,
7. North-West Administration of Hydrometeorological Service of Russia, St. Petersburg, Russian Federation,
8. Tallinn University of Technology, Tallinn, Estonia.