Browsing Bergen Open Research Archive by Author "Alendal, Guttorm"
Now showing items 1-20 of 26
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Assessing Model Uncertainties Through Proper Experimental Design
Hvidevold, Hilde Kristine; Alendal, Guttorm; Johannessen, Truls; Mannseth, Trond (Peer reviewed; Journal article, 2013)This paper assesses how parameter uncertainties in the model for rise velocity of CO2 droplets in the ocean cause uncertainties in their rise and dissolution in marine waters. The parameter uncertainties in the rise velocity ... -
Binary time series classification with Bayesian convolutional neural networks when monitoring for marine gas discharges
Gundersen, Kristian; Alendal, Guttorm; Oleynik, Anna; Blaser, Nello (Journal article; Peer reviewed, 2020-06-19)The world’s oceans are under stress from climate change, acidification and other human activities, and the UN has declared 2021–2030 as the decade for marine science. To monitor the marine waters, with the purpose of ... -
A comparison of Monte Carlo sampling methods for metabolic network models
Fallahi, Shirin; Skaug, Hans J.; Alendal, Guttorm (Journal article; Peer reviewed, 2020)Reaction rates (fluxes) in a metabolic network can be analyzed using constraint-based modeling which imposes a steady state assumption on the system. In a deterministic formulation of the problem the steady state assumption ... -
Cost efficient environmental survey paths for detecting continuous tracer discharges
Alendal, Guttorm (Peer reviewed; Journal article, 2017-07)Designing monitoring programs for detecting potential tracer discharges from unknown locations is challenging. The high variability of the environment may camouflage the anticipated anisotropic signal from a discharge, and ... -
Detection and quantification of CO2 seepage in seawater using the stoichiometric Cseep method: Results from a recent subsea CO2 release experiment in the North Sea
Omar, Abdirahman; García-Ibáñez, Maribel I.; Schaap, Allison; Oleynik, Anna; Esposito, Mario; Jeansson, Emil; Loucaides, Socratis; Thomas, Helmuth; Alendal, Guttorm (Journal article; Peer reviewed, 2021)Carbon Capture and Storage (CCS) is a potential significant mitigation strategy to combat climate change and ocean acidification. The technology is well understood but its current implementation must be scaled up nearly ... -
Effects of bottom drag and shelf slope steepnes on the currents along the shelf slope at Ormen Lange
Sørflaten, Agathe; Berntsen, Jarle; Alendal, Guttorm (Department of Applied Mathematics report, Research report, 2001-12) -
Experimental design for parameter estimation in steady-state linear models of metabolic networks
Frøysa, Håvard G; Skaug, Hans J.; Alendal, Guttorm (Journal article; Peer reviewed, 2020-01)Metabolic networks are typically large, containing many metabolites and reactions. Dynamical models that aim to simulate such networks will consist of a large number of ordinary differential equations, with many kinetic ... -
Flow over a backward-facing step, a numerical study comparing a zand a σ-coordinate model
Rygg, Kristin; Alendal, Guttorm; Haugan, Peter Mosby (Peer reviewed; Journal article, 2011)Homogeneous, nonrotating flow over a backward-facing rounded step is simulated using the 2D vertical version of two general circulation models, a z-coordinate model—the Massachusetts Institute of Technology general circulation ... -
Gas exploration beyond the shelf break : an oceanographic challenge
Thiem, Øyvind; Berntsen, Jarle; Eldevik, Tor; Alendal, Guttorm (Peer reviewed; Journal article, 2006-02)Norway's second largest gas field, Ormen Lange, is located 140 km west off Kristiansund at an unprecedented depth when it comes to exploration. It will be the first Norwegian project beyond the shelf break. Exploration and ... -
Impact and detectability of hypothetical CCS offshore seep scenarios as an aid to storage assurance and risk assessment
Blackford, Jerry; Alendal, Guttorm; Avlesen, Helge; Brereton, Ashley; Cazenave, Pierre W; Chen, Baixin; Dewar, Marius; Holt, Jason; Phelps, Jack (Journal article; Peer reviewed, 2020)Carbon Capture and Storage has the potential to make a significant contribution to the mitigation of climate change, however there is a regulatory and societal obligation to demonstrate storage robustness and minimal local ... -
Layout of CCS monitoring infrastructure with highest probability of detecting a footprint of a CO2 leak in a varying marine environment
Hvidevold, Hilde Kristine; Alendal, Guttorm; Johannessen, Truls; Ali, Alfatih Omer Mohammed Ahmed; Mannseth, Trond; Avlesen, Helge (Peer reviewed; Journal article, 2015-04-04)Monitoring of the marine environment for indications of a leak, or precursors of a leak, will be an intrinsic part of any subsea CO2 storage projects. A real challenge will be quantification of the probability of a given ... -
Modelling of deep-sea gravity currents using an integrated plume model
Alendal, Guttorm; Drange, Helge; Haugan, Peter Mosby (Geophysical Monograph Series; 85, Chapter, 1994) -
New Conceptual Toxicokinetic Model to Assess Synergistic Mixture Effects between the Aromatic Hydrocarbon β-Naphthoflavone and the Azole Nocodazole on the CYP1A Biomarker in a Fish Cell Line
Fallahi, Shirin; Mlnaříková, Marie; Alvord, Charlotte; Alendal, Guttorm; Frøysa, Håvard G; Lundh, Thorbjörn; Celander, Malin C. (Journal article; Peer reviewed, 2020)Toxicokinetic interactions with catabolic cytochrome P450 (CYP) enzymes can inhibit chemical elimination pathways and cause synergistic mixture effects. We have created a mathematical bottom-up model for a synergistic ... -
A numerical study of transport and spreading of gases from natural analogues of gas-seepage through the seafloor
Enstad, Lars Inge; Alendal, Guttorm; Haugan, Peter Mosby (Peer reviewed; Journal article, 2009-02)Natural leakages of CO2 are reported in the literature at mid ocean ridges and CH4 seepages in hydrocarbon rich ares. These could potentially serve as natural analogues of leakages from CO2 storages. In this study we have ... -
Ocean abyssal carbon experiments at 0.7 and 4 km depth
Haugan, Peter Mosby; Brewer, Peter G.; Peltzer, Edward T.; Walz, Peter; Aya, Izuo; Yamane, Kenji; Kojima, Ryuji; Nakajima, Yasuharu; Nakayama, Noriko; Hove, Joakim; Johannessen, Truls; Bellerby, Richard G. J.; Alendal, Guttorm (Journal article, 2005)Observations from small-scale (20 to 90 litres) CO2 experiments conducted off the coast of California at 684 m depth and at 3942 m depth are discussed. In both experiments, when the seawater velocity was sufficiently strong, ... -
Ocean release of fossil fuel CO2: A case study
Drange, Helge; Alendal, Guttorm; Johannessen, Ola M. (Journal article; Peer reviewed, 2001-07-01)The natural ocean uptake of the greenhouse gas CO2 can be accelerated by collecting and liquefying the gas from point sources, and by pumping it into the ocean at appropriate locations and at sufficient depths. Results ... -
Optimal sensors placement for detecting CO2 discharges from unknown locations on the seafloor
Oleynik, Anna; García-Ibáñez, Maribel I.; Blaser, Nello; Omar, Abdirahman; Alendal, Guttorm (Journal article; Peer reviewed, 2020-04)Assurance monitoring of the marine environment is a required and intrinsic part of CO2 storage project. To reduce the costs related to the monitoring effort, the monitoring program must be designed with optimal use of ... -
Parameterization of drag and dissolution of rising CO2 drops in seawater
Gangstø, Reidun; Haugan, Peter Mosby; Alendal, Guttorm (Journal article, 2005-05-24)In this work the dynamics and dissolution of a hydratecovered CO2 drop were studied, using a numeric model and data from one of very few CO2 experiments performed in the real ocean. A theory including the standard drag ... -
PVTx Properties of a Two-phase CO2 Jet from Ruptured Pipeline
Botnen, Helle Augdal; Omar, Abdirahman; Aavatsmark, Ivar; Alendal, Guttorm; Johannessen, Truls (Peer reviewed; Journal article, 2013)Span and Wagner equation of state (SW EOS) have been used to investigate changes in the thermodynamic properties of CO2 during a depressurization process from a pipeline into marine environment. The process is assumed to ... -
Semi-conditional variational auto-encoder for flow reconstruction and uncertainty quantification from limited observations
Gundersen, Kristian; Oleynik, Anna; Blaser, Nello; Alendal, Guttorm (Journal article; Peer reviewed, 2021)We present a new data-driven model to reconstruct nonlinear flow from spatially sparse observations. The proposed model is a version of a Conditional Variational Auto-Encoder (CVAE), which allows for probabilistic ...