Jaromir Jakacki

Toward Prediction of Environmental Arctic Change

Models help researchers understand past and present states as well as predict scenarios of environmental change in the Arctic. The authors analyze results on melting sea-ice from a regional coupled ice-ocean model and demonstrate their robustness independent of timescales for surface temperature and salinity relaxation.

On the Flow Through Bering Strait: A Synthesis of Model Results and Observations

Bering Strait is the only ocean connection between the Pacific and the Arctic. The flow through this narrow and shallow strait links the Pacific and Arctic oceans and impacts oceanic conditions downstream in the Chukchi Sea and the Western Arctic. We present a model synthesis of exchanges through Bering Strait at monthly to decadal time scales, including results from coupled ice-ocean models and observations. Significant quantities of heat and freshwater are delivered annually into the southern Chukchi Sea via Bering Strait. We quantify seasonal signals, along with interannual variability, over the course of 26 years of multiple model integrations. Volume transport and property fluxes are evaluated among several high-resolution model runs and compared with available moored observations. High-resolution models represent the bathymetry better, and may have a more realistic representation of the flow through the strait, although in terms of fluxes and mean properties, this is not always the case. We conclude that, (i) while some of the models used for Arctic studies achieve the correct order of magnitude for fluxes of volume, heat and freshwater, and have significant correlations with observational results, there is still a need for improvement and (ii) higher spatial resolution is needed to resolve features such as the Alaska Coastal Current (ACC). At the same time, additional measurements with better spatial coverage are needed to minimize uncertainties in observed estimates and to constrain models.

Spatiotemporal distribution of copepod populations in the Gulf of Gdansk (southern Baltic Sea)

In the present study, we used a 3D Coupled Ecosystem Model of Baltic Sea version 1 (3D CEMBSv1) coupled with a copepod model to examine the spatiotemporal distribution of two representative copepod populations in the Gulf of Gdansk (southern Baltic Sea) including Acartia spp. and Pseudocalanus minutus elongatus. The annual cycles simulated for 2000 under realistic weather and hydrographic conditions were studied with the three-dimensional version of the coupled ecosystem-copepod model in the south-eastern Baltic Sea. The paper presents the comparison of simulated and observed copepod development at two stations in the Gulf of Gdansk. A validation of influential state variables gives confidence that the model is able to calculate reliably the stage development of dominant species in the southern Baltic Sea. The number of generations was one for P. m. elongatus and 3–5 for Acartia spp.. A mean of five generations for the latter species per year were estimated in the coastal region and ca. three generations at the Gdansk Deep (in the open sea). Food concentration and temperature as the main factors controlling the development of the investigated copepods as well as salinity as a masking factor (i.e. salinity modifies the rate of their development) in the case of Pseudocalanus minutus elongatus are included in the present study.

Nonlinear acoustical methods in the detection of gassy sediments

The applieation oj nonlinear backscattering oj aeoustieal signals in deteetion ojgas bubbles in subsurjaee layer oj sediment oj the Gulf oj Gdansk is presented. Gas bubbles concentration was estimated assuming that nonlinear scattering in soft sediments is similar as in water. Summary, difJerence and double harmonics generated only by gas bubbles were reeorded and used jor bubble density estimation. Comparisons oj the eoneentrations reeeived from difJerent nonlinear components show generally agreement in cafeulated bubble density distributions, although values oj densities acquired from almost identieal volumes in a single transmission differ.

Deep sea habitats in the chemical warfare dumping areas of the Baltic Sea

The Baltic Sea is a severely disturbed marine ecosystem that has previously been used as a dumping ground for Chemical Warfare Agents (CW). The presence of unexploded underwater ordnance is an additional risk factor for offshore activities and an environmental risk for the natural resources of the sea. In this paper, the focus is on descriptions of the marine habitat based on the observations arising from studies linked to the CHEMSEA, MODUM and DAIMON projects. Investigated areas of Bornholm, Gotland and Gdańsk Deeps are similarly affected by the Baltic Sea eutrophication, however, at depths greater than 70m several differences in local hydrological regimes and pore-water heavy metal concentrations between those basins were observed. During the lifespan of presented studies, we were able to observe the effects of Major Baltic Inflow, that started in December 2014, on local biota and their habitats, especially in the Bornholm Deep area. Reappearance of several meiofauna taxa and one macrofauna specimen was observed approximately one year after this phenomenon, however its ecological effects already disappeared in March 2017. According to our findings and to the EUNIS Habitat Classification, the three reviewed areas should be characterized as Deep Sea Muddy Sands, while the presence of suspicious bomb-like objects both beneath and on top of the sediments confirms their CW dumpsite status.

An evaluation and implementation of the regional coupled ice-ocean model of the Baltic Sea

A three-dimensional, regional coupled ice-ocean model based on the open-source Community Earth System Model has been developed and implemented for the Baltic Sea. The model consists of 66 vertical levels and has a horizontal resolution of approx. 2.3 km. The paper focuses on sea ice component results, but the main changes have been introduced in the ocean part of the coupled model. The hydrodynamic part, being one of the most important components, has been also presented and validated. The ice model results were validated against the Synthetic Aperture Radar (SAR) and satellite data, and the method of validation based on probability was introduced. In the last two decades, satellite and model results show an increase in the ice extent over the whole Baltic Sea, which is an evidence of a negative trend in air temperature in recent decades and increasing of winter discharge from the catchment area.

Best Practices in Monitoring

This chapter summarizes the methods used within the MODUM project for monitoring chemical munition dumpsites. It includes general introduction to monitoring process, listing the requirements that are a basis for the establishment of full scale monitoring programme. It describes survey procedures, for locating dumped munitions, Sampling and analytical procedures for the detection of Chemical Warfare Agents, as well as the usage of fish as bioindicators are described. Modelling of pollutants originating from dumped munitions is presented and discussed. Only methods, which were proven to be most effective within the MODUM projects were selected, also data interpretation methods providing coherent information regarding the environmental risk are explained in details.

Estimation of Potential Leakage from Dumped Chemical Munitions in the Baltic Sea Based on Two Different Modelling Approaches

During the MODUM project two independent methods for estimation of potential leakage of dumped chemical munitions in the Baltic Sea have been developed. The first one is Lagrangian tracking of particles with random disturbance. The second one is using a passive tracer as a marker of potential leakage. The approaches have been developed in open source ocean models adapted for the Baltic Sea. But the models are quite different. The walking particles approach has been developed in the Princeton Ocean Model, which is nonlinear, free surface, hydrostatic, σ-coordinate, with an imbedded second and a half moment turbulence closure sub-model. The passive tracer was implemented in the Parallel Ocean Program – a z-level coordinate, general circulation ocean model that solves 3-dimensional primitive equations for stratified fluid, using the hydrostatic and Boussinesq approximations. Because of many differences in our approaches we skipped a detailed comparison of the presented results (however, this will be the subject of the next stage in our work). Although the approaches and the models are quite different, the results are comparable.

The Impact of the Sopot Pier Marina on the Local Surf Zone

An accelerated accumulation of sand in the area of the Sopot Pier Marina has been observed since 2010. The beach near the pier has grown by several meters and local depths have been decreasing. Before construction of the marina, spit type shoreline form had sometimes formed. But it has never begun to grow in the way it has grown after 2010, as a result of disturbed sediment transport in the local surf zone. The main goal of this work is to estimate where this process is going on. To assess the influence of the marina on the longshore drift, geometrical analysis of the existing marina has been performed and numerical model of sediment transport has been implemented. A simple analysis of the Sopot Pier dimensions suggests that the final form of growing spit will be tombolo. For the purpose of having an additional point of view, a numerical model of sediment transport based on MIKE by DHI product has been developed. The model results show that the Sopot Pier Marina has a strong influence on the sediment transport by generating a wave shadow zone. Consequently, it disturbs the continuity of sediment transport along the beach, which as a result impacts the costal line. The model indicates that 80% of this sand was transported from the area located southeast of the Sopot Pier, whereas the remaining 20% from the northwest area. Simulations showed that accumulated sand came from local surf zone and beaches. This result has been confirmed by bathymetry measurements performed by the Maritime Office in Gdynia.