Modelling environmentally friendly fairways using Lagrangian trajectories: a case study for the Gulf of Finland, the Baltic Sea

Abstract

We address possibilities of minimising environmental risks using statistical features of current-driven propagation of adverse impacts to the coast. The recently introduced method for finding the optimum locations of potentially dangerous activities (Soomere et al. in Proc Estonian Acad Sci 59:156-165, 2010) is expanded towards accounting for the spatial distributions of probabilities and times for reaching the coast for passively advecting particles released in different sea areas. These distributions are calculated using large sets of Lagrangian trajectories found from Eulerian velocity fields provided by the Rossby Centre Ocean Model with a horizontal resolution of 2 nautical miles for 1987-1991. The test area is the Gulf of Finland in the northeastern Baltic Sea. The potential gain using the optimum fairways from the Baltic Proper to the eastern part of the gulf is an up to 44% decrease in the probability of coastal pollution and a similar increase in the average time for reaching the coast. The optimum fairways are mostly located to the north of the gulf axis (by 2-8 km on average) and meander substantially in some sections. The robustness of this approach is quantified as the typical root mean square deviation (6-16 km) between the optimum fairways specified from different criteria. Drastic variations in the width of the 'corridors' for almost optimal fairways (2-30 km for the average width of 15 km) signifies that the sensitivity of the results with respect to small changes in the environmental criteria largely varies in different parts of the gulf.

How to value biodiversity in environmental management?

“…In the example above, identified management measures are also split into two categories: those that increase the safety of oil shipping, and those that optimising the oil recovery and prevent the pollution of the most important locations in the event of a spill. The first category includes technical and naval changes such as double-hulls, piloting obligations, winter navigation training for captains, and changes in fairways to avoid the most dangerous of fragile areas (Soomere et al, 2011). The second category focuses on one's readiness to respond to accidents in a timely and optimised manner, such as choosing the optimal distribution of the oil combatting vessels along the coast (Lehikoinen et al, 2013), prioritising the locations of oil booms to protect the most vulnerable species and areas , and choosing whether to use oil dispersants, among other strategies.…”

A probabilistic approach for a cost-benefit analysis of oil spill management under uncertainty: A Bayesian network model for the Gulf of Finland

“…the ENSI service (a navigational support system for oil tankers, H€ anninen et al, 2014) and the optimization of fairways in order to minimize the probability of coastal pollution (see e.g. Lehmann et al, 2014;Soomere et al, 2011aSoomere et al, , 2011bSoomere and Quak, 2013).…”

Identification of the environmentally safe fairway in the South-Western Baltic Sea and Kattegat

“…This feature is apparently not decisive for relatively short trajectories (below 10 days) but may still affect the resulting quantification of the offshore domains. There are, however, other aspects that apparently have a comparable impact on the accuracy of the entire procedure such as the overall sensitivity of the optimum location on the resolution of the circulation model (Andrejev et al 2011) or the choice of the measure for the environmental risks (Soomere et al , 2011c. A study of the relevant effects is, however, out of the scope of this paper.…”

“…The deviation of the two versions of the optimum fairway from each other in the central Arkona Basin (Fig. 12c) suggest that this area has relatively low gradients of the underlying fields of probabilities and particle age and thus may serve as a natural area of reduced risk in terms of coastal pollution (Soomere et al 2011c). As both the versions of the fairway tend to head to Öresund, they are shifted to the south by few grid points at 12.6°E, 54.7°N, after which the scheme on Fig.…”