Corinna schrum

University of Bergen, Geophysical Institute, Faculty Member

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Papers by Corinna schrum

Climate impacts on ocean acidification in the North Sea and Baltic Sea: a modelling study

ABSTRACT CO2 increase in the atmosphere does not only potentially change the overall climate, but... more ABSTRACT CO2 increase in the atmosphere does not only potentially change the overall climate, but also increase the dissolved inorganic carbon (DIC) content in the ocean by ocean-atmosphere gas exchange leading to a decrease in oceanic ph (acidification). Hence, it has both direct (via acidification) and indirect (via changes in atmospheric fields) implications for marine ecosystems and their productivity. On the other hand, changes in primary production would likewise impact the DIC content and could potentially alter the process of acidification on different temporal scales (seasonal, inter-annual, and decadal). Here, we extended the 3d coupled ecosystem model ECOSMO II by formulations for carbon chemistry and applied the model system to the North Sea and Baltic Sea in order to investigate ocean acidification in that specific region. We specifically aim in disentangling direct and indirect impacts of changes in atmospheric CO2 on acidification. Therefore we will first, present results from a multi-decadal model hind cast (1948-2008) to describe the dynamics in ocean acidification with respect to the different time scales. Secondly, we apply downscaled products from General Circulation Models to project future climate impacts (2070-2100) on acidification. And thirdly, we will present results from cross-experiments, where we investigate the influence of future CO2 increase under present day atmospheric condition and vice versa. These scenarios allow disentangling the direct and indirect impacts on the process of acidification comparative in the North Sea and Baltic Sea.

4.1 The effects of future climate change on the physical oceanography and comparisons of the mean and variability of the future physical properties with present day conditions

by M. Huret and Corinna schrum

Past and Current Climate Change

by J. Cappelen, Deliang Chen, Mirosław Miętus, Corinna schrum, Joanna Wibig, and Eirik Førland

Regional Climate Studies, 2008

Page 1. 2 Past and Current Climate Change Raino Heino, Heikki Tuomenvirta, Valery S. Vuglinsky, B... more

Past and Current Climate Change

by Deliang Chen, Corinna schrum, Anders Omstedt, Timo Vihma, Heikki Tuomenvirta, and Miroslaw Mietus

Regional Climate Studies, 2008

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ICES/CIEM

by Corinna schrum, Francis Gohin, and Bertrand Saulquin

Coupling ecosystem and individual-based models to simulate the influence of environmental variability on potential growth and survival of larval sprat ( Sprattus sprattus L.) in the North Sea

by Myron Peck, Corinna schrum, and Wilfried Kühn

Fisheries Oceanography, 2008

To investigate the impact of changing environmental conditions in the North Sea on the distributi... more To investigate the impact of changing environmental conditions in the North Sea on the distribution and survival of early life stages of a marine fish species, we employed a suite of coupled model components: (i) an Eulerian coupled hydrodynamic ⁄ecosystem (Nutrients, Phyto-, Zooplankton, Detritus) model to provide both 3-D fields of hydrographical properties, and spatially and temporally variable prey fields; (ii) a Lagrangian transport model to simulate temporal changes in cohort distribution; and (iii) an individual-based model (IBM) to depict foraging, growth and survival of fish early life stages. In this application, the IBM was parameterized for sprat (Sprattus sprattus L.) and included non-feeding (egg and yolk-sac larval) stages as well as foraging and growth subroutines for feeding (post-yolk sac) larvae. Sensitivity analyses indicated that the angle of visual acuity, assimilation efficiency and the maximum food consumption rate were the most critical intrinsic model parameters. As an example, we applied this model system for 1990 in the North Sea. Results included not only information concerning the interplay of temperature and prey availability on larval fish survival and growth but also information on mechanisms underlying larval fish aggregation within frontal zones. The good agreement between modelled and in situ estimates of sprat distribution and growth rates in the German Bight suggested that interconnecting these different models provided an expedient tool to scrutinize basic processes in fish population dynamics.

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HORIZONS How best to include the effects of climate-driven forcing on prey fields in larval fish individual-based models

by Corinna schrum and Myron Peck

If we intend to examine the indirect effects of climate variability on the vital rates of key mar... more If we intend to examine the indirect effects of climate variability on the vital rates of key marine species, climate-induced changes in the spatial-temporal dynamics of prey must be resolved. Recently, structured population simulations have been coupled to ecosystem (nutrient-phytoplanktonzooplankton-detritus, NPZD) models to derive prey fields. Model-derived prey fields offer advantages (e.g. increased spatial-temporal coverage, direct links to climate forcing). In contrast, employing structured population simulations (e.g. stage-based copepod models) has several disadvantages, including the lack of realistic utilization of phytoplankton production, the absence of boundary condition data and a vastly increased coupled model complexity. To avoid the pitfalls limiting the utility of structured population models, we argue for a more simple approach for obtaining a size-structured prey field using NPZD model estimates of bulk zooplankton carbon and in situ zooplankton abundance-atsize data. The approach was developed to obtain prey fields for a larval fish individual-based model (IBM), but the method may offer wide applicability. Moreover, our approach greatly simplifies the coupling of NPZD models and larval fish IBMs and is an example of the reduction in model complexity that will be critical to the development of end-to-end ecosystem models that use, for example, a rhomboid approach to examine trophodynamic climate impacts at basin scales.

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Biomass changes and trophic amplification of plankton in a warmer ocean

by Corinna schrum, Marina Chifflet, Guillem Chust, and Eric Machu

Global Change Biology, 2014

Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationship... more Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 AE 0.05°C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and regional models, imply the need for caution when extending these considerations into higher trophic levels.

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Linking anchovy and sprat distributions with bio-physical oceanographic features: a Bay of Biscay - North Sea comparison

by Corinna schrum and Francis Gohin

Distribution patterns of small-pelagic fish reveal migration at seasonal and regional scale, with... more Distribution patterns of small-pelagic fish reveal migration at seasonal and regional scale, with nota ble differences among species. For each species, differ ent environmental physical and biological factors determine the characteristics of its habitats, and potentially explain its observed migration pattern. In the Bay of Biscay, anchovy gathers in the southern part of the Bay from winter to spring when

Historical reconstruction of the Aral Sea shrinking by a full 3-D wetting and drying model ECOSMO

Geoscientific Model Development Discussions, 2008

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly ... more

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Dense water formation and circulation in the Barents Sea

Deep-sea Research Part I-oceanographic Research Papers, 2011

Dense water masses from Arctic shelf seas are an important part of the Arctic thermohaline system... more Dense water masses from Arctic shelf seas are an important part of the Arctic thermohaline system. We present previously unpublished observations from shallow banks in the Barents Sea, which reveal large interannual variability in dense water temperature and salinity. To examine the formation and circulation of dense water, and the processes governing interannual variability, a regional coupled ice-ocean model is applied to the Barents Sea for the period 1948–2007. Volume and characteristics of dense water are investigated with respect to the initial autumn surface salinity, atmospheric cooling, and sea-ice growth (salt flux). In the southern Barents Sea (Spitsbergen Bank and Central Bank) dense water formation is associated with advection of Atlantic Water into the Barents Sea and corresponding variations in initial salinities and heat loss at the air–sea interface. The characteristics of the dense water on the Spitsbergen Bank and Central Bank are thus determined by the regional climate of the Barents Sea. Preconditioning is also important to dense water variability on the northern banks, and can be related to local ice melt (Great Bank) and properties of the Novaya Zemlya Coastal Current (Novaya Zemlya Bank). The dense water mainly exits the Barents Sea between Frans Josef Land and Novaya Zemlya, where it constitutes 63% (1.2 Sv) of the net outflow and has an average density of 1028.07 kg m−3. An amount of 0.4 Sv enters the Arctic Ocean between Svalbard and Frans Josef Land. Covering 9% of the ocean area, the banks contribute with approximately 1/3 of the exported dense water. Formation on the banks is more important when the Barents Sea is in a cold state (less Atlantic Water inflow, more sea-ice). During warm periods with high throughflow more dense water is produced broadly over the shelf by general cooling of the northward flowing Atlantic Water. However, our results indicate that during extremely warm periods (1950s and late 2000s) the total export of dense water to the Arctic Ocean becomes strongly reduced.► Large temporal and spatial variability in observed dense water characteristics. ► Regional differences in dense water formation processes on shallow banks identified. ► Elucidation of dense water circulation within the Barents Sea. ► Dense water contribution from banks compared to regional dense water formation. ► Dense water outflow to the Arctic Ocean strongly reduced during warm periods.

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Long-Term Retrospective Analysis of Mackerel Spawning in the North Sea: A New Time Series and Modeling Approach to CPR Data

by Sophie G Pitois and Corinna schrum

PLOS One, 2012

We present a unique view of mackerel (Scomber scombrus) in the North Sea based on a new time seri... more We present a unique view of mackerel (Scomber scombrus) in the North Sea based on a new time series of larvae caught by the Continuous Plankton Recorder (CPR) survey from 1948-2005, covering the period both before and after the collapse of the North Sea stock. Hydrographic backtrack modelling suggested that the effect of advection is very limited between spawning and larvae capture in the CPR survey. Using a statistical technique not previously applied to CPR data, we then generated a larval index that accounts for both catchability as well as spatial and temporal autocorrelation. The resulting time series documents the significant decrease of spawning from before 1970 to recent depleted levels. Spatial distributions of the larvae, and thus the spawning area, showed a shift from early to recent decades, suggesting that the central North Sea is no longer as important as the areas further west and south. These results provide a consistent and unique perspective on the dynamics of mackerel in this region and can potentially resolve many of the unresolved questions about this stock.

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Linking anchovy and sprat distributions with bio-physical oceanographic features: a Bay of Biscay - North Sea comparison

by Corinna schrum and Bertrand Saulquin

Ein klimatologischer Datensatz für Temperatur und Salzgehalt in Nordsee und Ostsee

Ocean Dynamics, 1999

A climatological monthly mean data set for temperature and salinity in the area of the North Sea ... more A climatological monthly mean data set for temperature and salinity in the area of the North Sea and Baltic Sea is presented. More than 3.1 million temperature observations (2.9 million for salinity) collected during the period 1900 to 1996 were compiled and gridded on a 10×10 km grid with 18 vertical levels. The monthly mean horizontal distributions of temperature and salinity are presented for the sea surface as well as for the bottom. Additionally, the monthly temperature and salinity distributions along 4 sections in the North Sea and Baltic Sea are given. Furthermore, the seasonal cycle of thermal stratification in both marginal seas, derived from an analysis of the gridded monthly data set, is presented. Es wird einklimatologischer Datensatz von Monatsmittelwerten der Temperatur und des Salzgehalts für das Gebiet der Nord-und Ostsee vorgestellt. Mehr als 3,1 Millionen Meßwerte der Temperatur (2,9 Millionen für den Salzgehalt) aus denJahren 1900 bis 1996 wurden gesammelt, aufbereitet und auf ein 3-dimensionales Gitter mit einer Auflösung von10×10 km und18 vertikalen Schichten interpoliert. Die Horizontalverteilungen von Temperatur und Salzgehalt werden für die Oberfläche wie auch für den Meeresboden dargestellt. Zusätzlich werden monatliche Temperatur-und Salzgehaltsverteilungen auf vier Vertikalschnitten durch Nord-und Ostsee präsentiert. Darüberhinaus erfolgt eine Darstellung des saisonalenVeriaufs der Temperaturschichtung in beiden Randmeeren, abgeleitet aus dem auf dem Gitter vorliegenden Datensatz.

Mesoskalige Strukturen, Flüsse und Wassermassen-VariabilitÄt in der Deutschen Bucht, dargestellt durch die Kustos-Experimente und numerische Modelle

Ocean Dynamics, 1999

In this article, the hydrographic conditions are described which prevailed in the German Bight du... more In this article, the hydrographic conditions are described which prevailed in the German Bight during the three KUSTOS experiments carried out in summer 1994, spring 1995, and winter 1996. It presents the physical background for the companion articles of this volume and provides insight into the complicated and highly variable hydrodynamics of the German Bight. Typically for the German Bight, the distribution of temperature and salinity in the near-bottom layer was found to relate strongly to the topography in all experiments, and variability in the vertical structure showed the expected seasonal pattern. The thermal and haline stratification were found to coincide in most cases, indicating a clear marking of surface and bottom water masses. Between the three KUSTOS experiments, the intensity of salinity fronts varied strongly, with stronger fronts in spring and weaker gradients in summer and winter, but from the limited number of observations this pattern cannot be generalised. The observed temperature and/or salinity patterns differ strongly from the average long-term situation, as expected in a highly variable area. To a large degree, this variability is caused by mesoscale features which - owing to their transient nature - are not well resolved by in-situ observations during the experiments and, therefore, numerical models are used to complement the observations. Finally, the overall mass transport through the German Bight during the KUSTOS experiments, estimated from a North Sea circulation model and a salt water budget and freshwater balance, ranges between 34 (strong cyclonic circulation) and -3 km3/d (weak anticyclonic circulation). North Sea water advection into the German Bight dominates river runoff by a factor of ∼15 (spring 1995) to ∼49 (winter 1996). However, in situations with a low through-flow in combination with a high ratio of freshwater inflow, residence times of river water can be high, thereby aggravating any harmful effects of riverine contaminants. In diesem Artikel werden die vorherrschenden hydrographischen Bedingungen wÄhrend der drei KUSTOS-Experimente beschrieben, die im Sommer 1994, Frühling 1995 und Winter 1996 in der Deutschen Bucht durchgeführt wurden. Er stellt den physikalischen Hintergrund für die anderen Artikel dieses Bandes dar und bietet einen Einblick in die komplizierte und überaus variable Hydrodynamik der Deutschen Bucht. In allen Experimenten ergab sich ein direkter Zusammenhang zwischen den bodennahen Verteilungen von Temperatur und Salzgehalt mit der Topographie. Die in den Experimenten beobachtete VariabilitÄt in den vertikalen Strukturen zeigte die zu erwartenden saisonalen Muster. Es wurde festgestellt, da\ sich die vertikalen Gradienten der Temperatur und des Salzgehaltes in den meisten FÄllen deckten, wodurch die Unterschiede der Wassermassen am Boden und an der OberflÄche deutlich werden. Die KUSTOS Experimente zeigen eine saisonal verÄnderliche IntensitÄt der Salzgehaltsfronten, mit im Frühjahr stÄrkeren und im Sommer und Winter schwÄcheren Gradienten. Allerdings lassen die verfügbaren Ergebnisse keine Verallgemeinerung dieses Ergebnisses zu. Keine der beobachteten Temperaturoder Salzgehaltsmuster zeigen einen engen Bezug zu der mittleren Lage über lange ZeitrÄume hinweg, wodurch sich die gro\e Bandbreite der VariabilitÄt zeigt. Da mesoskalige Merkmale, entsprechend ihrer kurzlebigen Natur, von den in-situ Beobachtungen wÄhrend der Experimente nicht gut aufgelöst wurden, wurden numerische Modelle benutzt, um die VariabilitÄt teilweise erklÄren zu können. Mit einem Zirkulationsmodell wird der Brutto-Massentransport durch die Deutsche Bucht der Nordsee berechnet; die Ergebnisse zeigen eine hohe VariabilitÄt des Massentransportes. Transporte in die Deutsche Bucht wÄhrend der KUSTOS Experimente reichen von 34 bis-3 km3/Tag, von starker zyklonaler zu schwacher anti-zyklonaler Zirkulation. Eine für die KUSTOS Experimente aufgestellte Salz-und Frischwasserbilanz bestÄtigt die Modellergebnisse und offenbart die Dominanz des in die Deutsche Bucht einströmenden Nordseewassers über die FlusswassereintrÄge. Vor allem im Fall geringen Massentransportes in Verbindung mit einem hohen Anteil an Frischwasserzuflu\ bedingt die entsprechend höhere Verweildauer eine VerstÄrkung der negativen Effekte der vom Flusswasser mitgeführten Schadstoffe.

North Sea sensitivity to atmospheric forcing

Journal of Marine Systems, 2011

The sensitivity of North Sea physics and phytoplankton production to atmospheric forcing has been... more The sensitivity of North Sea physics and phytoplankton production to atmospheric forcing has been studied by performing perturbations of the atmospheric forcing fields through a number of model simulations. The perturbations are kept in the range of expected climate change, to give a first indication of the climate change impacts on regional systems. The model simulations suggest that an increase in air temperature and short wave radiation will increase sea surface temperature, while an increase in wind will decrease it. Increased wind will increase the transports into the North Sea, while the other atmospheric forcings only have a small impact on that. Combining the perturbations indicates a smaller stratified area and a deeper mixed layer. Primary production is expected to increase, with an increase in wind speed having the largest impact.►Sensitivity of North Sea physics and lower trophic levels to atmospheric forcing. ►Number of simulations where permutations of one by one forcing variable were done. ►Permutations within expected climate change to give a first indication of the climate change impacts on regional systems. ►Results compared to natural variability of today's climate.

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Modelling air-sea exchange in the Barents Sea by using a coupled regional ice-ocean model. Evaluation of modelling strategies

Meteorologische Zeitschrift, 2005

... GIBSON, R., P. KALLBERG, S. UPPALA, 1996: The ECMWF Re-Analysis (ERA) project. ... JAKOBSSON,... more

Ocean surface heat flux variability in the Barents Sea

Journal of Marine Systems, 2010

A 40 year (1958–1997) hindcast simulation from the regional coupled ice–ocean model HAMSOM is use... more A 40 year (1958–1997) hindcast simulation from the regional coupled ice–ocean model HAMSOM is used to study climate relevant processes in the Barents Sea and their interannual to decadal variability. Compared to observations the model captures the variability in temperature and ice extent in a satisfying manner. The heat input through the Barents Sea Opening (BSO) is effectively lost through intense atmosphere–ocean heat exchange within the Barents Sea. Correlation analysis suggests that heat transport through the BSO leads the Barents Sea heat content by 1–10 months, while the heat content leads the air–sea heat fluxes with 1–5 months. Averaged over the period the advected heat input is 32 TW, augmented by 79 TW of shortwave radiation and reduced by 113 TW through longwave radiation and latent and sensible heat loss. Including the sensible heat loss at the ice–ocean boundary yields an oceanic heat loss in the Barents Sea of 40 TW. Cooling of Atlantic Water is very efficient just east of the BSO, and contributes to 50% of the total heat loss. Significant positive trends in both heat transport through the BSO and solar radiation, combined with a reduction in seasonal ice cover cause increased oceanic heat loss. Excess heat still enters the Barents Sea and a significant warming is observed in the northern areas.Sea-ice acts as an effective insulator against oceanic heat loss resulting in 4 TW of net heat input at the sea-ice surface. This heat flux balances the ice–ocean heat budget and the corresponding ice melt compensates for net ice production at the ice–ocean interface and ice advection into the Barents Sea.

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Past and current climate change

Assessment of Climate …, 2008

Page 1. 2 Past and Current Climate Change Raino Heino, Heikki Tuomenvirta, Valery S. Vuglinsky, B... more

Decadal variations in the stratification and circulation patterns of the North Sea. Are the 1990s unusual

ICES. Mar. Sci. Symp, 2004

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