Net precipitation over the Baltic Sea for one year using several methods

Precipitation and evaporation over the Baltic Sea are calculated for a one-year period from September 1998 to August 1999 by four different tools, the two atmospheric regional models HIRLAM and REMO, the oceanographic model PROBE-Baltic in combination with the SMHI (1 × 1)° database and Interpolated Fields, based essentially on ship measurements. The investigated period is slightly warmer and wetter than the climatological mean. Correlation coefficients of the differently calculated latent heat fluxes vary between 0.81 (HIRLAM and REMO) and 0.56 (SMHI/PROBE-Baltic and Interpolated Fields), while the correlation coefficients between model fluxes and measured fluxes range from 0.61 and 0.78. Deviations of simulated and interpolated monthly precipitation over the Baltic Sea are less than ±5 mm in the southern Baltic and up to 20 mm near the Finnish coast for the one-year period. The methods simulate the annual cycle of precipitation and evaporation of the Baltic Proper in a similar manner with a broad maximum of net precipitation in spring and early summer and a minimum in late summer. The annual averages of net precipitation of the Baltic Proper range from 57 mm (REMO) to 262 mm (HIRLAM) and for the Baltic Sea from 96 mm (SMHI/PROBE-Baltic) to 209 mm (HIRLAM). This range is considered to give the uncertainty of present-day determination of the net precipitation over the Baltic Sea

Progress in physical oceanography of the Baltic Sea during the 2003-2014 period

We review progress in Baltic Sea physical oceanography (including sea ice and atmosphere-land interactions) and Baltic Sea modelling, focusing on research related to BALTEX Phase II and other relevant work during the 2003-2014 period. The major advances achieved in this period are: Meteorological databases are now available to the research community, partly as station data, with a growing number of freely available gridded datasets on decadal and centennial time scales. The free availability of meteorological datasets supports the development of more accurate forcing functions for Baltic Sea models. In the last decade, oceanographic data have become much more accessible and new important measurement platforms, such as FerryBoxes and satellites, have provided better temporally and spatially resolved observations. Our understanding of how large-scale atmospheric circulation affects the Baltic Sea climate, particularly in winter, has improved. Internal variability is strong illustrating the dominant stochastic behaviour of the atmosphere. The heat and water cycles of the Baltic Sea are better understood. The importance of surface waves in air-sea interaction is better understood, and Stokes drift and Langmuir circulation have been identified as likely playing an important role in surface water mixing in sea water. We better understand sea ice dynamics and thermodynamics in the coastal zone where sea ice interaction between land and sea is crucial. The Baltic Sea's various straits and sills are of increasing interest in seeking to understand water exchange and mixing. There has been increased research into the Baltic Sea coastal zone, particularly into upwelling, in the past decade. Modelling of the Baltic Sea-North Sea system, including the development of coupled land-sea-atmosphere models, has improved. Despite marked progress in Baltic Sea research over the last decade, several gaps remain in our knowledge and understanding. The current understanding of salinity changes is limited, and future projections of salinity evolution are uncertain. In addition, modelling of the hydrological cycle in atmospheric climate models is severely biased. More detailed investigations of regional precipitation and evaporation patterns (including runoff), atmospheric variability, highly saline water inflows, exchange between sub-basins, circulation, and especially turbulent mixing are still needed. Furthermore, more highly resolved oceanographic models are necessary. In addition, models that incorporate more advanced carbon cycle and ecosystem descriptions and improved description of water-sediment interactions are needed. There is also a need for new climate projections and simulations with improved atmospheric and oceanographic coupled model systems. These and other research challenges are addressed by the recently formed Baltic Earth research programme, the successor of the BALTEX programme, which ended in 2013. Baltic Earth will treat anthropogenic changes and impacts together with their natural drivers. Baltic Earth will serve as a network for earth system sciences in the region, following in the BALTEX tradition but in a wider context. (C) 2014 The Authors. Published by Elsevier Ltd.Peer reviewe

Four Regional Marine Biodiversity Studies: Approaches and Contributions to Ecosystem-Based Management

We compare objectives and approaches of four regional studies of marine biodiversity: Gulf of Maine Area Census of Marine Life, Baltic Sea History of Marine Animal Populations, Great Barrier Reef Seabed Biodiversity Project, and Gulf of Mexico Biodiversity Project. Each program was designed as an "ecosystem" scale but was created independently and executed differently. Each lasted 8 to 10 years, including several years to refine program objectives, raise funding, and develop research networks. All resulted in improved baseline data and in new, or revised, data systems. Each contributed to the creation or evolution of interdisciplinary teams, and to regional, national, or international science-management linkages. To date, there have been differing extents of delivery and use of scientific information to and by management, with greatest integration by the program designed around specific management questions. We evaluate each research program's relative emphasis on three principal elements of biodiversity organization: composition, structure, and function. This approach is used to analyze existing ecosystem-wide biodiversity knowledge and to assess what is known and where gaps exist. In all four of these systems and studies, there is a relative paucity of investigation on functional elements of biodiversity, when compared with compositional and structural elements. This is symptomatic of the current state of the science. Substantial investment in understanding one or more biodiversity element(s) will allow issues to be addressed in a timely and more integrative fashion. Evaluating research needs and possible approaches across specific elements of biodiversity organization can facilitate planning of future studies and lead to more effective communication between scientists, managers, and stakeholders. Building a general approach that captures how various studies have focused on different biodiversity elements can also contribute to meta-analyses of worldwide experience in scientific research to support ecosystem-based management

Knowledge of the Baltic Sea physics gained during the BALTEX and related programmes

Review is given about the main results of the oceanographic component of the BALTEX research programme (one of the six continental scale experiments within GEWEX-WCRP to study water and energy cycles in the regional climate system) and related programmes/projects over the last 10 years. Working closely together with two other components – regional meteorology and hydrology of the Baltic Sea drainage basin – oceanographic research has considerably improved the understanding of and ability to model the Baltic Sea marine system. In the Baltic Sea physics seven different broad topics are identified where knowledge has significantly improved. These are reviewed together with a discussion of gaps in knowledge. The focus is on the water and energy cycles of the Baltic Sea, but various aspects of forcing and validation data and modelling are also discussed. The major advances achieved through BALTEX and related programmes are: • Meteorological, hydrological, ocean and ice data are now available for the research community. • Progress in understanding of the strong impact of large-scale atmospheric circulation on Baltic Sea circulation, water mass exchange, sea ice evolution, and changes in the ocean conditions of the Baltic Sea. • Progress in understanding of the importance of strait flows in the exchange of water into and within the Baltic Sea. • Progress in understanding of intra-basin processes. • Ocean models introduced into Baltic Sea water and energy studies. • Development of turbulence models and 3D ocean circulation models for application to the Baltic Sea. • Improved Baltic Sea ice modelling and increased understanding of the need for coupled atmosphere–ice–ocean-land models