Spatially resolved past and projected changes of the suitable thermal habitat of North Sea cod (Gadus morhua) under climate change

x,298 p. : il.; 23 cm

A multi-decadal meridional displacement of the Subpolar Front in the Newfoundland Basin

Observations since the 1950s show a multi-decadal cycle of a meridional displacement of the Subpolar Front (SPF) in the Newfoundland Basin (NFB) in the North Atlantic. The SPF displacement is associated with corresponding variations in the path of the North Atlantic Current. We use the ocean general circulation model MPIOM with enhanced horizontal and vertical resolutions and forced with NCEP/NCAR reanalysis data to study the relation of the SPF displacement to atmospheric forcing, intensities of the subpolar gyre (SPG) and Meridional Overturning Circulation (MOC), and Labrador Sea Water (LSW) volume. The simulations indicate that the SPF displacement is associated with a circulation anomaly between the SPG and the subtropical gyre (STG), an inter-gyre gyre with a multi-decadal time scale. A sensitivity experiment indicates that both wind stress curl (WSC) and heat fluxes (which match LSW changes) contribute to the circulation anomalies in the frontal region and to the SPF displacement. An anticyclonic inter-gyre gyre is related to negative WSC and LSW anomalies and to a SPF north of its climatological position, indicating an expanding STG. A cyclonic inter-gyre gyre is related to positive WSC and LSW anomalies and a SPF south of its climatological position, indicating an expanding SPG. Therefore, the mean latitudinal position of the SPF in the NFB (a "SPF index") could be an indicator of the amount of LSW in the inter-gyre region. Spreading of LSW anomalies intensifies the MOC, suggesting our SPF index as predictor of the MOC intensity at multi-decadal time scales. The meridional displacement of the SPF has a pronounced influence on the meridional heat transport, both on its gyre and overturning components.<br

PREFACE MS45 report : pelagic fish and prey field dynamics in their habitat

This milestone report contains an update on the analysis of Yellowfin tuna (YFT) bioclimatic modelling as well as the synthesis based on D12.2 and MS42. Local Yellowfin tuna (Thunnus albacares, YFT) catch rates covering the area 10-20°N latitude and 10-30°W longitude were analysed to indicate catch opportunities in Cape Verde waters. Local catch-per-unit-effort (CPUEl) is treated as a function of stock size, Ns, and environmental factors, Vi, the latter at local scale or at stock scale in terms of climate indices. Of the two indices applied to indicate stock size, i.e. the Japanese long line stock index (LLindex) and the so-called Index4 series, the LLindex

Global ocean biogeochemistry model HAMOCC: Model architecture and performance as component of the MPI-Earth System Model in different CMIP5 experimental realizations

Ocean biogeochemistry is a novel standard component of fifth phase of the Coupled Model Intercomparison Project (CMIP5) experiments which project future climate change caused by anthropogenic emissions of greenhouse gases. Of particular interest here is the evolution of the oceanic sink of carbon and the oceanic contribution to the climate-carbon cycle feedback loop. The Hamburg ocean carbon cycle model (HAMOCC), a component of the Max Planck Institute for Meteorology Earth system model (MPI-ESM), is employed to address these challenges. In this paper we describe the version of HAMOCC used in the CMIP5 experiments (HAMOCC 5.2) and its implementation in the MPI-ESM to provide a documentation and basis for future CMIP5-related studies. Modeled present day distributions of biogeochemical variables calculated in two different horizontal resolutions compare fairly well with observations. Statistical metrics indicate that the model performs better at the ocean surface and worse in the ocean interior. There is a tendency for improvements in the higher resolution model configuration in representing deeper ocean variables; however, there is little to no improvement at the ocean surface. An experiment with interactive carbon cycle driven by emissions of CO2 produces a 25% higher variability in the oceanic carbon uptake over the historical period than the same model forced by prescribed atmospheric CO2 concentrations. Furthermore, a climate warming of 3.5 K projected at atmospheric CO2 concentration of four times the preindustrial value, reduced the atmosphere-ocean CO2 flux by 1 GtC yr−1. Overall, the model shows consistent results in different configurations, being suitable for the type of simulations required within the CMIP5 experimental desig

Rapport PREFACE MS45 : dynamique des poissons pélagiques et des champs de proies dans leur habitat

This milestone report contains an update on the analysis of Yellowfin tuna (YFT) bioclimatic modelling as well as the synthesis based on D12.2 and MS42. Local Yellowfin tuna (Thunnus albacares, YFT) catch rates covering the area 10-20°N latitude and 10-30°W longitude were analysed to indicate catch opportunities in Cape Verde waters. Local catch-per-unit-effort (CPUEl) is treated as a function of stock size, Ns, and environmental factors, Vi, the latter at local scale or at stock scale in terms of climate indices. Of the two indices applied to indicate stock size, i.e. the Japanese long line stock index (LLindex) and the so-called Index4 series, the LLindex.Ce rapport d'étape contient une mise à jour de l'analyse de la modélisation bioclimatique du thon à nageoires jaunes (YFT) ainsi que la synthèse basée sur D12.2 et MS42. Les taux de capture locaux de l'albacore (Thunnus albacares, YFT) couvrant la zone de 10-20° de latitude nord et de 10-30° de longitude ouest ont été analysés pour indiquer les possibilités de capture dans les eaux du Cap-Vert. La capture locale par unité d'effort (CPUEl) est traitée en fonction de la taille du stock, Ns, et des facteurs environnementaux, Vi, ces derniers à l'échelle locale ou à l'échelle du stock en termes d'indices climatiques. Parmi les deux indices appliqués pour indiquer la taille des stocks, à savoir l'indice japonais des stocks de poissons à long terme (LLindex) et la série dite "Index4", le LLindex

The effect of geometry on ice shelf ocean cavity ventilation: a laboratory experiment

A laboratory experiment is constructed to simulate the density-driven circulation under an idealized Antarctic ice shelf and to investigate the flux of dense and freshwater in and out of the ice shelf cavity. Our results confirm that the ice front can act as a dynamic barrier that partially inhibits fluid from entering or exiting the ice shelf cavity, away from two wall-trapped boundary currents. This barrier results in a density jump across the ice front and in the creation of a zonal current which runs parallel to the ice front. However despite the barrier imposed by the ice front, there is still a significant amount of exchange of water in and out of the cavity. This exchange takes place through two dense and fresh gravity plumes which are constrained to flow along the sides of the domain by the Coriolis force. The flux through the gravity plumes and strength of the dynamic barrier are shown to be sensitive to changes in the ice shelf geometry and changes in the buoyancy fluxes which drive the flow