Central limit theorems for multilevel Monte Carlo methods

In this work, we show that uniform integrability is not a necessary condition for central limit theorems (CLT) to hold for normalized multilevel Monte Carlo (MLMC) estimators and we provide near optimal weaker conditions under which the CLT is achieved. In particular, if the variance decay rate dominates the computational cost rate (i.e., $\beta > \gamma$), we prove that the CLT applies to the standard (variance minimizing) MLMC estimator. For other settings where the CLT may not apply to the standard MLMC estimator, we propose an alternative estimator, called the mass-shifted MLMC estimator, to which the CLT always applies. This comes at a small efficiency loss: the computational cost of achieving mean square approximation error $\mathcal{O}(\epsilon^2)$ is at worst a factor $\mathcal{O}(\log(1/\epsilon))$ higher with the mass-shifted estimator than with the standard one

Science for management advice in the Arctic Ocean: The International Council for the Exploration of the Sea (ICES)

The International Council for the Exploration of the Sea was established in 1902 and is one of the oldest marine science institutions in the world. It has aged well – today it provides scientific advice for the management of the marine environment and the natural resources there to governments and regional commissions for fisheries and environment in the Northeast Atlantic. It has 20 member nations and a network of 6000 scientists and 700 institutes as the foundation of its activities, spanning from basic marine science via data management to the provision of scientific advice on marine management. The purpose of this chapter is to provide an overview of the ICES organization and its functions, discuss its provision of scientific advice and thereby its role at the science-policy interface in the North Atlantic and the Arctic, including how this role is changing with the development of integrated, ecosystem based management of the oceans. The final part of the chapter addresses the current governance of Arctic marine science and its science – policy interfaces

Marine Spatial Planning: Norway´s management plans

Since the adoption of a government white paper on ocean governance in 2001, Norway has worked on the development and implementation of marine spatial planning in the format of regional management plans. Management plans for the Barents Sea and the oceans off northern Norway and the Norwegian Sea were adopted in 2006 and 2009, respectively, and a management plan for the North Sea is planned for 2013. A key aspect of the plans is integrated assessment of the cumulative impacts on marine ecosystem from human activities (fisheries, petroleum, marine transportation, etc) on the one hand, and external sources (climate change, long range pollution) on the other. Another important feature is the identification of valuable and vulnerable areas requiring special management measures. These valuable areas have been used as input to define the spatial measures in the plans which includes routing systems for international ship traffic and zoning plans for petroleum activities. Fishing activities is also partially regulated used spatial measures such as MPAs and temporary closed areas. A monitoring system is set up with indicators and reference levels. The plan has been implemented through the regular governance structure without the establishment of new, formal institutions or new jurisdiction. An inter-- ]ministerial committee oversees the work, guided by three working groups. A revised version of the Barents Sea plan will be adopted late in 2010, taking marine spatial planning in Norway into its second generation. Key words: Marine spatial planning, Norway, Barents Sea, ecosystem approac

The development of scientific cooperation under the Norway - Russia fisheries regime in the Barents Sea

publishedVersio

Multilevel ensemble Kalman filtering for spatio-temporal processes

We design and analyse the performance of a multilevel ensemble Kalman filter method (MLEnKF) for filtering settings where the underlying state-space model is an infinite-dimensional spatio-temporal process. We consider underlying models that needs to be simulated by numerical methods, with discretization in both space and time. The multilevel Monte Carlo (MLMC) sampling strategy, achieving variance reduction through pairwise coupling of ensemble particles on neighboring resolutions, is used in the sample-moment step of MLEnKF to produce an efficient hierarchical filtering method for spatio-temporal models. Under sufficient regularity, MLEnKF is proven to be more efficient for weak approximations than EnKF, asymptotically in the large-ensemble and fine-numerical-resolution limit. Numerical examples support our theoretical findings.Comment: Version 1: 39 pages, 4 figures.arXiv admin note: substantial text overlap with arXiv:1608.08558 . Version 2 (this version): 52 pages, 6 figures. Revision primarily of the introduction and the numerical examples sectio

The 2010 Norway-Russia Marine Boundary Agreement and Bilateral Cooperation on Integrated Oceans Management

More than three decades in the making, the 2010 agreement between Norway and Russia on a bounadry in the Barents Sea establishes a boundary, continues cooperation in fisheries, and lays the framework for cooperation on petroleum deposits straddling the boundary. The importance of the boundary goes well beyond the Barents Sea, as it demonstrated the capability of Arctic countries to resolve issues in a peaceful manner on the basis of international law. The agreement settles the most important outstanding foreign policy issue between the two countries and opens up new opportunities for cooperation. The article gives a brief overview of the agreement, the its negotiation and its implications at various levels of governance