Blar i Faculty of Mathematics and Natural Sciences på forfatter "Drange, Helge"
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Annual carbon fluxes in the upper Greenland Sea based on measurements and a box-model approach
Anderson, Leif G.; Drange, Helge; Chierici, M.; Fransson, A.; Johannessen, Truls; Skjelvan, Ingunn; Rey, Francisco (Peer reviewed; Journal article, 2000-07)Measurements of nitrate and the carbonate system parameters performed mainly from 1993 to 1997 have been used to estimate the evolution of the concentration fields over the year in the surface and underlying waters of the ... -
A brief history of climate – the northern seas from the Last Glacial Maximum to global warming
Eldevik, Tor; Risebrobakken, Bjørg; Bjune, Anne Elisabeth; Andersson, Carin; Birks, Harry John Betteley; Dokken, Trond Martin; Drange, Helge; Glessmer, Mirjam Sophia; Li, Camille; Nilsen, Jan Even Øie; Otterå, Odd Helge; Richter, Kristin; Skagseth, Øystein (Peer reviewed; Journal article, 2014-12)The understanding of climate and climate change is fundamentally concerned with two things: a well-defined and sufficiently complete climate record to be explained, for example of observed temperature, and a relevant ... -
Description and evaluation of the Bergen climate model: ARPEGE coupled with MICOM
Furevik, Tore; Bentsen, Mats; Drange, Helge; Kindem, I. K. T.; Kvamstø, Nils Gunnar; Sorteberg, Asgeir (Peer reviewed; Journal article, 2003-07)A new coupled atmosphere–ocean–sea ice model has been developed, named the Bergen Climate Model (BCM). It consists of the atmospheric model ARPEGE/IFS, together with a global version of the ocean model MICOM including a ... -
Diagnosing and Understanding the AMOC Biases in NorESM
Ivanova, Detelina; Bentsen, Mats; Ilicak, Mehmet; Gao, Chuncheng; Drange, Helge (Conference poster, 2014)We investigate the Atlantic Meridional Overturning Circulation (AMOC) in the Norwegian Earth System Model (NorESM) featuring isopycnal ocean component (MICOM). The Coupled Model Intercomparison Phase 5 (CMIP5) NorESM ... -
Diagnosing ocean tracer transport from Sellafield and Dounreay by equivalent diffusion and age
Orre, Steinar; Gao, Yongqi; Drange, Helge; Deleersnijder, Eric (Peer reviewed; Journal article, 2008-09-27)A simple approach for estimating the equivalent diffusion for diagnosing tracer transport is proposed. Two different expressions are derived; one is based directly on an analytical solution of the two-dimensional ... -
The Effect of Diapycnal Mixing on the Ventilation and CFC-11 Uptake in the Southern Ocean
Gao, Yongqi; Drange, Helge (Advances in Atmospheric Sciences;21(5), Journal article, 2004-03-04)The Miami Isopycnic Coordinate Ocean Model (MICOM) is used to investigate the effect of diapycnal mixing on the oceanic uptake of CFC-11 and the ventilation of the surface waters in the Southern Ocean (south of 45°S). Three ... -
Effects of diapycnal and isopycnal mixing on the ventilation of CFCs in the North Atlantic in an isopycnic coordinate OGCM
Gao, Yongqi; Drange, Helge; Bentsen, Mats (Peer reviewed; Journal article, 2003)Simulated distributions of the chlorofluorocarbons CFC-11 and CFC-12 are used to examine the ventilation of the North Atlantic Ocean in a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). Three simulations ... -
Effects of simulated natural variability on Arctic temperature
Sorteberg, Asgeir; Furevik, Tore; Drange, Helge; Kvamstø, Nils Gunnar (Journal article, 2005-09-23)A five-member ensemble with a coupled atmospheresea ice-ocean model is used to examine the effects of natural variability on climate projections for the Arctic. The individual ensemble members are initialized from a 300 ... -
Effects of solar irradiance forcing on the ocean circulation and sea-ice in the North Atlantic in an isopycnic coordinate ocean general circulation model
Otterå, Odd Helge; Drange, Helge (Peer reviewed; Journal article, 2004)The sensitivity of the ocean circulation to changes in solar irradiance is examined using an isopycnic coordinate, global ocean general circulation model (OGCM) coupled to a thermodynamic/dynamic sea-ice model. In the ... -
Effects of solar irradiance forcing on the ocean circulation and sea-ice in the North Atlantic in an isopycnic coordinate ocean general circulation model
Otterå, Odd Helge; Drange, Helge (Tellus;56A(2), Journal article, 2004-03)The sensitivity of the ocean circulation to changes in solar irradiance is examined using an isopycnic coordinate, global ocean general circulation model (OGCM) coupled to a thermodynamic/dynamic sea-ice model. In the ... -
Global and regional surface cooling in a warming climate: a multi-model analysis
Medhaug, Iselin; Drange, Helge (Peer reviewed; Journal article, 2015)Instrumental temperature records show that the global climate may experience decadal-scale periods without warming despite a long-term warming trend. We analysed 17 global climate models participating in phase 5 of the ... -
Inception of the Northern European Ice Sheet due to contrasting ocean and insolation forcing
Risebrobakken, Bjørg; Dokken, Trond Martin; Otterå, Odd Helge; Jansen, Eystein; Gao, Yongqi; Drange, Helge (Peer reviewed; Journal article, 2007-01)About 115,000 years ago the last interglacial reached its terminus and nucleation of new ice sheet growth was initiated. Evidence from the northernmost Nordic Seas indicate that the inception of the last glacial was related ... -
Modeling the middle Pliocene climate with a global atmospheric general circulation model
Jiang, Dabang; Wang, Huijun; Ding, Zhongli; Lang, Xianmei; Drange, Helge (Peer reviewed; Journal article, 2005-07-27)A new climate simulation for the middle Pliocene (ca. 3 Ma BP) is performed by a global grid-point atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP AGCM) with boundary conditions ... -
Nordic Seas Heat Loss, Atlantic Inflow, and Arctic Sea Ice cover over the last century
Smedsrud, Lars Henrik; Muilwijk, Morven; Eldevik, Tor; Årthun, Marius; Brakstad, Ailin; Madonna, Erica; Lauvset, Siv Kari; Spensberger, Clemens; Born, Andreas; Drange, Helge; Jeansson, Emil; Li, Camille; Olsen, Are; Skagseth, Øystein; Slater, Donald; Straneo, Fiammetta; Våge, Kjetil (Journal article; Peer reviewed, 2021)Poleward ocean heat transport is a key process in the earth system. We detail and review the northward Atlantic Water (AW) flow, Arctic Ocean heat transport, and heat loss to the atmosphere since 1900 in relation to sea ... -
The North Atlantic Oscillation and greenhouse-gas forcing
Kuzmina, Svetlana I.; Bengtsson, Lennart; Johannessen, Ola M.; Drange, Helge; Bobylev, Leonid P.; Miles, Martin W. (Peer reviewed; Journal article, 2005-02-17)The results of 12 coupled climate models participating in the Coupled Model Intercomparison Project (CMIP2) are compared together with observational data in order to investigate: 1) How the current generation of climate ... -
On the recent time history and forcing of the inflow of Atlantic Water to the Arctic Mediterranean
Nilsen, Jan Even Øie; Hátún, Hjalmar; Sandø, Anne Britt; Bethke, Ingo; Laurantin, Olivier; Gao, Yongqi; Drange, Helge; Furevik, Tore (Extended Abstract for The ACIA International Scientific Symposium on Climate Change in the Arctic, Conference lecture, 2004) -
A Possible Feedback Mechanism Involving the Arctic Freshwater, the Arctic Sea Ice, and the North Atlantic Drift
Otterå, Odd Helge; Drange, Helge (Advances in Atmospheric Sciences;21( 5), Journal article, 2004-03-15)Model studies point to enhanced warming and to increased freshwater fluxes to high northern latitudes in response to global warming. In order to address possible feedbacks in the ice-ocean system in response to such changes, ... -
Seasonal to Decadal Temperature Variations in the Faroe-Shetland Inflow Waters
Hátún, Hjalmar; Sandø, Anne Britt; Drange, Helge; Bentsen, Mats (AGU Geophysical Monograph Series;158, Chapter, 2005)A 53 years hind-cast simulation with a regional version of the Nansen Center version of the Miami Isopycnic Coordinate Ocean Model (MICOM) has been conducted to explore the nature of the observed seasonal to inter-annual ... -
The sensitivity of the present day Atlantic meriodinal overturning circulation to freshwater forcing
Otterå, Odd Helge; Drange, Helge; Bentsen, Mats; Kvamstø, Nils Gunnar; Jiang, Dabang (Peer reviewed; Journal article, 2003-09-09)Mounting evidence indicates that the Atlantic Meridional Overturning Circulation (AMOC) was strongly reduced during cold climate episodes in the past, possible due to freshwater influx from glacial melting. It is also ... -
Simulated North Atlantic-Nordic Seas water mass exchanges in an isopycnic coordinate OGCM
Nilsen, Jan Even Øie; Gao, Yongqi; Drange, Helge; Furevik, Tore; Bentsen, Mats (Journal article, 2003-05-29)The variability in the volume exchanges between the North Atlantic and the Nordic Seas during the last 50 years is investigated using a synoptic forced, global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). ...