Publikasjoner
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Humlum, Ole; Christiansen, Hanne H; Mortensen, Lis E.; Stuart, Finlay M. & Stone, John O.
(2023).
Weichselian Glaciation of the Faroe Islands.
Bulletin of the Geological Society of Denmark.
ISSN 0011-6297.
72,
s. 19–100.
doi:
10.37570/bgsd-2023-72-02.
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This paper presents a new complete field mapping of glacial landscapes, landforms and sediments in the Faroe Islands, supplemented by observations from bathymetric maps of the Faroe Shelf. In addition, previous investigations of Quaternary and espe-cially the Weichselian glaciation of the archipelago are reviewed. New cosmogenic nuclide exposure ages indicate that the last extensive glaciation of the Faroe Islands occurred during the Late Weichselian, most likely during the Last Glacial Maximum (LGM; c. 26.5–19.0 cal. ka BP), although a Younger Dryas (c. 12.9–11.7 cal. ka BP) age cannot be entirely excluded. Geomorphological mapping provides a background for reconstructing the extent and type of the glaciation of the Faroe Islands. The reconstructed Weichselian glaciation appears to have had the character of an exten-sive valley glaciation, with several marine glacier termini. The present glaciation of southern Spitsbergen, Svalbard, represents a modern analogue of the reconstructed Weichselian glaciation in the Faroe Islands. The lack of raised coastal features in the Faroe Islands, also at protected sites, suggests that postglacial isostatic uplift was smaller than post-LGM eustatic sea level rise. Numerical glacier reconstructions carried out for different extents of the last extensive Faroese glaciation suggest that such limited postglacial isostatic crustal uplift requires that the Faroe Shelf was not extensively glaciated during the Late Weichselian, but it doubtless was so during at least one of the previous Quaternary glaciations.
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Bertone, Aldo; Barboux, Chloé; Bodin, Xavier; Bolch, Tobias; Brardinoni, Francesco & Caduff, Rafael
[Vis alle 18 forfattere av denne artikkelen]
(2022).
Incorporating InSAR kinematics into rock glacier inventories: insights from 11 regions worldwide.
The Cryosphere.
ISSN 1994-0416.
16(7),
s. 2769–2792.
doi:
10.5194/tc-16-2769-2022.
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Rock glaciers are landforms related to permafrost creep that are sensitive to climate variability and change. Their spatial distribution and kinematic behaviour can be critical for managing water resources and geohazards in periglacial areas. Rock glaciers have been inventoried for decades worldwide, often without assessment of their kinematics. The availability of remote sensing data however makes the inclusion of kinematic information potentially feasible, but requires a common methodology in order to create homogeneous inventories. In this context, the International Permafrost Association (IPA) Action Group on rock glacier inventories and kinematics (2018–2023), with the support of the European Space Agency (ESA) Permafrost Climate Change Initiative (CCI) project, is defining standard guidelines for the inclusion of kinematic information within inventories. Here, we demonstrate the feasibility of applying common rules proposed by the Action Group in 11 regions worldwide. Spaceborne interferometric synthetic aperture radar (InSAR) was used to characterise identifiable moving areas related to rock glaciers, applying a manual and a semi-automated approach. Subsequently, these areas were used to assign kinematic information to rock glaciers in existing or newly compiled inventories. More than 5000 moving areas and more than 3600 rock glaciers were classified according to their kinematics. The method and the preliminary results were analysed. We identified drawbacks related to the intrinsic limitations of InSAR and to various applied strategies regarding the integration of non-moving rock glaciers in some investigated regions. This is the first internationally coordinated work that incorporates kinematic attributes within rock glacier inventories at a global scale. The results show the value of designing standardised inventorying procedures for periglacial geomorphology.
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Garcia-Oteyza, J.; Oliva, M.; Palacios, D.; Fernández-Fernández, J.M.; Schimmelpfennig, I. & Andrés, N.
[Vis alle 18 forfattere av denne artikkelen]
(2022).
Late Glacial deglaciation of the Zackenberg area, NE Greenland.
Geomorphology.
ISSN 0169-555X.
401.
doi:
10.1016/j.geomorph.2022.108125.
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The Greenland Ice Sheet (GrIS) is a key component of the global climate system. However, our current understanding of the spatio-temporal oscillations and landscape transformation of the GrIS margins since the last glacial cycle is still incomplete. The objective of this work is to study the deglaciation of the Zackenberg Valley (74°N, 20°E), NE Greenland, and the origin of the derived landforms. Based on extensive fieldwork and high-detail geomorphological mapping we identified the different types of landforms, from which those of glacial and paraglacial origin were used to understand the processes driving regional environmental evolution. We applied cosmic-ray exposure (CRE) dating to 32 samples taken from erosive and depositional glacial landforms distributed across the valley. Geomorphological evidence shows that >800-m-thick Late Quaternary glacier filled the valleys and fjords and covered mountain summits. In subsequent phases, as ice thickness decreased, the glacier was limited to the interior of the valley, leaving several lateral moraines. The deglaciation of the Zackenberg Valley that started by ~13.7–12.5 ka also accelerated slope paraglacial processes. Many blocks from lateral moraines were remobilized and fell, reaching the valley floor where they covered the thinning glacier tongue; transforming it into a debris-covered glacier that subsequently melted gradually. By ca. 10.5 ka, the last remnants of glacial ice disappeared from the Zackenberg Valley floor, a chronology of deglaciation that is similar to that observed in other sites across NE Greenland. The results of this work must be considered in similar studies, reinforcing the need to support CRE ages of the different geomorphological phases with paleoclimatic data from other sedimentary records.
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Humlum, Ole; Stordahl, Kjell & Solheim, Jan Erik
(2013).
The phase relation between atmospheric carbon dioxide and global temperature.
Global and Planetary Change.
ISSN 0921-8181.
100,
s. 51–69.
doi:
10.1016/j.gloplacha.2012.08.008.
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Abstract
Using data series on atmospheric carbon dioxide and global temperatures we investigate the phase relation (leads/lags) between these for the period January 1980 to December 2011. Ice cores show atmospheric CO2 variations to lag behind atmospheric temperature changes on a century to millennium scale, but modern temperature is expected to lag changes in atmospheric CO2, as the atmospheric temperature increase since about 1975 generally is assumed to be caused by the modern increase in CO2. In our analysis we use eight well-known datasets; 1) globally averaged well-mixed marine boundary layer CO2 data, 2) HadCRUT3 surface air temperature data, 3) GISS surface air temperature data, 4) NCDC surface air temperature data, 5) HadSST2 sea surface data, 6) UAH lower troposphere temperature data series, 7) CDIAC data on release of anthropogene CO2, and 8) GWP data on volcanic eruptions. Annual cycles are present in all datasets except 7) and 8), and to remove the influence of these we analyze 12-month averaged data. We find a high degree of co-variation between all data series except 7) and 8), but with changes in CO2 always lagging changes in temperature. The maximum positive correlation between CO2 and temperature is found for CO2 lagging 11–12 months in relation to global sea surface temperature, 9.5-10 months to global surface air temperature, and about 9 months to global lower troposphere temperature. The correlation between changes in ocean temperatures and atmospheric CO2 is high, but do not explain all observed changes.
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Lilleøren, Karianne Staalesen; Humlum, Ole; Nesje, Atle & Etzelmuller, Bernd
(2013).
Holocene development and geomorphic processes at Omnsbreen, southern Norway: Evidence for glacier-permafrost interactions.
The Holocene.
ISSN 0959-6836.
23(6),
s. 796–809.
doi:
10.1177/0959683612471984.
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Lilleøren, Karianne Staalesen; Etzelmuller, Bernd; Schuler, Thomas; Gisnås, Kjersti & Humlum, Ole
(2012).
The relative age of mountain permafrost - estimation of Holocene permafrost limits in Norway.
Global and Planetary Change.
ISSN 0921-8181.
92-93,
s. 209–223.
doi:
10.1016/j.gloplacha.2012.05.016.
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Rouyet, Line; Lilleøren, Karianne Staalesen; Etzelmüller, Bernd; Kääb, Andreas Max; Christiansen, Hanne H. & Humlum, Ole
[Vis alle 9 forfattere av denne artikkelen]
(2022).
SAR satellite remote sensing for mapping and monitoring Norwegian rock glaciers.
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Rouyet, Line; Christiansen, Hanne H; Humlum, Ole; McDonald, Ashton B. & Lauknes, Tom Rune
(2021).
Integration of geomorphological mapping and InSAR kinematics for a comprehensive inventory of rock glaciers in Nordenskiöld Land.
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Schrott, Lothar & Humlum, Ole
(2017).
Introduction to the special issue: permafrost and periglacial research from coasts to mountains.
Geomorphology.
ISSN 0169-555X.
293,
s. 319–320.
doi:
10.1016/j.geomorph.2017.08.034.
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Yndestad, Harald; Solheim, Jan-Erik; Humlum, Ole & Falk-Petersen, Stig
(2016).
The Solar System Large Planets influence on a new Maunder Minimum.
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Humlum, Ole
(2015).
Climate change since 1850: What may be learnt from observations?
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Humlum, Ole
(2013).
Hvordan blir Svalbards klima de neste 20-25 år?
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Foredraget tar for seg naturlige klimavariasjoner i forhold til menneskeskapte
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Lilleøren, Karianne Staalesen; Etzelmuller, Bernd; Gisnås, Kjersti; Humlum, Ole & Schuler, Thomas
(2013).
Relative age and Holocene distribution of permafrost in Norway.
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Mörner, N.-A.; Tattersall, R.; Humlum, Ole & Solheim, J.-E.
(2013).
General conclusions regarding the Planetary–Solar–Terrestrial interaction.
Pattern Recognition.
ISSN 0031-3203.
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Humlum, Ole
(2013).
Mapping natural climate variations: why and how?
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Humlum, Ole
(2013).
Examples of natural climate variations missing in climate models; challenges for future climate models.
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Humlum, Ole
(2013).
Svalbard climate and meteorology; research history and modern status.
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Humlum, Ole
(2013).
Svalbard; a geological and topographic overview.
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Humlum, Ole & Vold, Henrik Brattli
(2013).
Nå kommer kalde, harde vintre.
[Internett].
NRK Viten.
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Solaktiviteten er på en nedadgående trend, og en britisk forsker mener det er 25 prosent sjanse for at sola blir like svak som under "den lille istid" for 400 år siden. Forskerne er uenige om konsekvensene.
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Humlum, Ole
(2013).
Klimaendringer og årsakssammenheng.
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Humlum, Ole
(2013).
Mindre og mindre global oppvarmning.
geoforskning.no.
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Ny norsk forskning antyder at fremtidens temperaturstigning blir lavere enn tidligere antatt. Det bør få konsekvenser for dagens klimamodeller, mener Ole Humlum.
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Humlum, Ole
(2012).
Past, present and future climate of the European Arctic.
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Humlum, Ole
(2012).
CO2 og klimaskepsis.
[Radio].
NRK P2 EKKO.
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Karlsson, Svenoluf & Humlum, Ole
(2012).
Arktisk Isminimum.
[Avis].
Katternö 2012 Vol. 3, p.42.
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Humlum, Ole
(2012).
Temperatur og atmosfærisk CO2.
geoforskning.no.
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I en nylig publisert forskningsartikkel hevdet Humlum og medforfatterne at temperaturendringer styrer atmosfæriske endringer av CO2. Artikkelen har blitt heftig debattert, og her svarer Humlum på noe av kritikken og forsøker å oppklare enkelte misforståelser.
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Setså, Ronny & Humlum, Ole
(2012).
Temperaturen styrer CO2-nivået – ikke omvendt.
[Internett].
GEO365 Nettavisen for geomiljøet.
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Data fra iskjerner har tidligere demonstrert at atmosfæriske endringer i CO2 har etterfulgt temperaturendringer de siste hundretusener av år. Nå har vi funnet bevis for at dette også gjelder i moderne tid, forteller Ole Humlum, professor ved Institutt for geofag ved Universitetet i Oslo og professor II ved Universitetet på Svalbard.
Artikkelen, som snart publiseres i tidsskriftet Global and Planetary Change, peker i retning av at det er temperaturendringene på Jorda som har styrt økningen i konsentrasjonen av karbondioksid i atmosfæren de siste tiårene.
Forskerne bak artikkelen er, foruten Ole Humlum, Kjell Stordahl, statistiker ved Telenor og Jan-Erik Solheim, professor emeritus ved Institutt for fysikk og teknologi ved Universitetet i Tromsø
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Solheim, Jan-Erik & Humlum, Ole
(2012).
Jordrotasjonen, Sola, klima og nordlys.
Astronomi.
ISSN 0802-7587.
42(5),
s. 20–25.
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Solheim, Jan-Erik; Humlum, Ole & Stordahl, Kjell
(2012).
Solar Signals in Temperature Series from Locations in and near the North Atlantic.
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Solar Signals in Temperature Series from Locations In and Near the North Atlantic
Jan Erik SOLHEIM 1, Ole HUMLUM 2, Kjell STORDAHL 3
1 University of Tromso, Norway
2 University of Oslo, Norway
3 Telenor, Norway
Corresponding author: janesol@online.no +Presenter
We have analyzed temperature series from Nordic and Northern Atlantic locations by means of Fourier and wavelet analyses and compared with similar analysis of solar activity proxies. The sunspot period and the Gleissberg period are identified in several of the local time series. In addition we have analyzed the last 4000 years of the reconstructed GISP2 surface temperarture from interior Greenland, which gives a low resolution temperature series until 1855 AD. Here we find dominant periods of the order 1100 and 2800 years, which are also present in the solar proxies covering similar periods. A forecast based on the strongest periods explains the temperature rise experienced after the Little Ice age. A temperature maxium is expected some time this century, before the cooling experienced since the Holocene maximum again will continue.
A relation between the length of the sunspot cycle and the mean temperature in sunspot cycles for locations in Norway show that 25 – 60 % of the temperature variations the last 150 years may be attributed to the Sun. For locations as Iceland, Faroe Island and Svalbard the contribution is as high as 72%, For the costal locations investigated a lag of 10-12 years gives the highest correlation between sunspot length and temperature. This is an indication of ocean currents as the main vehicle for transporting heat from lower latitudes to the North Atlantic
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Humlum, Ole
(2015).
Commentary and Analysis on the Whitehead & Associates 2014 NSW Sea-level Report.
NIPCC.
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Carter R.M., de Lange W., Hansen, J.M., Humlum O., Idso C., Kear, D., Legates, D., Mörner, N.A., Ollier C., Singer F. & Soon W. 2014. Commentary and Analysis on the Whitehead & Associates 2014NSWSea-LevelReport. Nongovernmental International Panel on Climate Change (NIPCC), NIPCC Reference: E13.7268, 44 pp.
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Lilleøren, Karianne Staalesen; Etzelmuller, Bernd & Humlum, Ole
(2012).
Late-Pleistocene and Holocene mountain permafrost geomorphology of Norway and Iceland.
Unipub forlag.
ISSN 1501-7710.
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Publisert
10. des. 2013 21:17
- Sist endret
1. juni 2023 16:16