Helle Astrid Kjær
Associate Professor
Physics of Ice, Climate and Earth
Tagensvej 16
2200 København N.
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A first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination
Mojtabavi, S., Wilhelms, F., Cook, Eliza, Siwan M., D., Sinnl, Giulia, Skov Jensen, M., Dahl-Jensen, Dorthe, Svensson, Anders, Vinther, Bo Møllesøe, Kipfstuhl, S., Gwydion, J., Karlsson, N. B., Henrique Faria, S., Gkinis, Vasileios, Kjær, Helle Astrid, Erhardt, T., Berben, S. M. P., Nisancioglu, K. H., Koldtoft, Iben & Rasmussen, Sune Olander, 27 Sep 2020, In: Climate of the Past. 16, 6, p. 2359-2380 21 p.Research output: Contribution to journal › Journal article › peer-review
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Editorial: Impure Snow and Ice in Remote Areas: Arctic, Antarctica and High Mountains
Ming, J., Lee, K., Wang, F., Zhang, T. & Kjær, Helle Astrid, 20 Jan 2022, In: Frontiers in Earth Science. 9, 2 p., 780068.Research output: Contribution to journal › Editorial › peer-review
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Nanoplastics measurements in Northern and Southern polar ice
Materic, D., Kjær, Helle Astrid, Vallelonga, P., Tison, J., Rockmann, T. & Holzinger, R., 15 May 2022, In: Environmental Research. 208, 9 p., 112741.Research output: Contribution to journal › Journal article › peer-review
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A 120 000-year record of sea ice in the North Atlantic?
Maffezzoli, N., Vallelonga, P., Edwards, R., Saiz-Lopez, A., Turetta, C., Kjær, Helle Astrid, Barbante, C., Vinther, Bo Møllesøe & Spolaor, A., 19 Dec 2019, In: Climate of the Past. 15, 6, p. 2031-2051Research output: Contribution to journal › Journal article › peer-review
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Sea ice in the northern North Atlantic through the Holocene: Evidence from ice cores and marine sediment records
Maffezzoli, N., Risebrobakken, B., Miles, M. W., Vallelonga, P., Berben, S. M. P., Scoto, F., Edwards, R., Kjær, Helle Astrid, Sadatzki, H., Saiz-Lopez, A., Turetta, C., Barbante, C., Vinther, Bo Møllesøe & Spolaor, A., 3 Nov 2021, In: Quaternary Science Reviews. 273, 17 p., 107249.Research output: Contribution to journal › Journal article › peer-review
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Magnitude, frequency and climate forcing of global volcanism during the last glacial period as seen in Greenland and Antarctic ice cores (60-9 ka)
Lin, Jiamei, Svensson, Anders, Hvidberg, Christine Schøtt, Lohmann, Johannes Jakob, Kristiansen, S., Dahl-Jensen, Dorthe, Steffensen, Jørgen Peder, Rasmussen, Sune Olander, Cook, Eliza, Kjær, Helle Astrid, Vinther, Bo Møllesøe, Fischer, H., Stocker, T., Sigl, M., Bigler, M., Severi, M., Traversi, R. & Mulvaney, R., 15 Mar 2022, In: Climate of the Past. 18, 3, p. 485-506 22 p.Research output: Contribution to journal › Journal article › peer-review
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Magnitude, frequency and climate forcing of global volcanism during the last glacial period as seen in Greenland and Antarctic ice cores (60–9 ka)
Lin, Jiamei, Svensson, Anders, Hvidberg, Christine Schøtt, Lohmann, Johannes Jakob, Kristiansen, S., Dahl-Jensen, Dorthe, Steffensen, Jørgen Peder, Rasmussen, Sune Olander, Cook, Eliza, Kjær, Helle Astrid, Vinther, Bo Møllesøe, Fischer, H., Stocker, T., Sigl, M., Bigler, M., Severi, M., Traversi, R. & Mulvaney, R., 9 Aug 2021, 45 p. Copernicus/EGU.Research output: Other contribution › Research
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Forty years later: High resolution continuous flow analysis of the Dye3 ice core
Kjær, Helle Astrid, Harlan, Meg, Vallelonga, P., Svensson, Anders, Blunier, Thomas, Sowers, T., Menking, J. A., Campo, A. D., Venkatesh, J., Liisberg, J., Soestmeyer, D., Morris, V., Vaughn, B. & Vinther, Bo Møllesøe, 4 Mar 2021, 2 p. Copernicus/EGU.Research output: Other contribution › Research
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Laboratory supervision of MSc projects -Qualitative interviews, thematic analysis, and recommendations for the supervisor
Kjær, Helle Astrid, 23 May 2018, Improving University Science Teaching and Learning Pedagogical Projects 2018. Institut for Naturfagenes Didaktik ed. København, Danmark: Københavns Universitet, Vol. 12. p. 91-105 (Improving University Science Teaching and Learning - Pedagogical Projects).Research output: Chapter in Book/Report/Conference proceeding › Book chapter › Education
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A portable Lightweight In Situ Analysis (LISA) box for ice and snow analysis
Kjær, Helle Astrid, Hauge, L. L., Simonsen, M., Yoldi, Zuriñe, Koldtoft, Iben, Hörholdt, M., Freitag, J., Kipfstuhl, S., Svensson, Anders & Vallelonga, P., 2 Mar 2021, In: The Cryosphere Discussions. 19 p.Research output: Contribution to journal › Journal article › peer-review
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Iskerner-et indblik i fortidens klimaforandringer
Kjær, Helle Astrid & Balslev-Clausen, D., 2 Apr 2011, Aspekter af dansk kemi i det 20. og 21. århundrede. 1 ed. København: Kemi Forlaget, p. 65-70 5 p.Research output: Chapter in Book/Report/Conference proceeding › Book chapter › Communication
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Supplementary material to "A portable Lightweight In Situ Analysis (LISA) box for ice and snow analysis"
Kjær, Helle Astrid, Hauge, L. L., Simonsen, M., Yoldi, Zuriñe, Koldtoft, Iben, Hörholdt, M., Freitag, J., Kipfstuhl, S., Svensson, Anders & Vallelonga, P., 2 Mar 2021Research output: Other contribution › Research
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Greenland ice cores constrain glacial atmospheric fluxes of phosphorus
Kjær, Helle Astrid, Dallmayr, R., Gabrieli, J., Goto-Azuma, K., Hirabayashi, M., Svensson, Anders & Vallelonga, P. T., 29 Oct 2015, In: Journal of Geophysical Research: Biogeosciences. 120, 20Research output: Contribution to journal › Journal article › peer-review
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A novel method for the detection of acidity in ice cores
Kjær, Helle Astrid, Vallelonga, P. T. & Svensson, Anders, 27 Apr 2014, European Geosciences Union General Assembly 2014, 16, 27 April – 02 May 2014. European Geosciences Union ed. Vienna, Austria, 1526Research output: Chapter in Book/Report/Conference proceeding › Article in proceedings › Research › peer-review
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Constraining Glacial input of phosphorus to the oceans based on Greenland ice core evidence
Kjær, Helle Astrid, Gotto-Azuma, K., Dallmayr, R., Hirabayashi, M., Vallelonga, P. T. & Svensson, Anders, 27 Apr 2014, European Geosciences Union General Assembly 2014, 16, 27 April – 02 May 2014. European Geosciences Union ed. Vienna, Austria, 1524Research output: Chapter in Book/Report/Conference proceeding › Article in proceedings › Research › peer-review
Assessment of the temperature, precipitation and snow in the RCM HIRHAM4 at 25 km resolution: Danish Climate Centre Report 09-08
Kjær, Helle Astrid, 2009, Assessment of the temperature, precipitation and snow in the RCM HIRHAM4 at 25 km resolution: Danish Climate Centre Report 09-08. Danmarks Meterologiske Institut (DMI)Research output: Chapter in Book/Report/Conference proceeding › Report chapter › Research
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Continuous Flow Analysis Method for Determination of Dissolved Reactive Phosphorus in Ice Cores
Kjær, Helle Astrid, Vallelonga, P. T., Svensson, Anders, Elleskov L. Kristensen, M., Tibuleac, C. & Bigler, M., 5 Nov 2013, In: Environmental Science & Technology (Washington). 47, 21, p. 12325-12332Research output: Contribution to journal › Journal article › peer-review
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An Optical Dye Method for Continuous Determination of Acidity in Ice Cores
Kjær, Helle Astrid, Vallelonga, P. T., Svensson, Anders, Kristensen, M. E., Tibuleac, C., Winstrup, M. & Kipfstuhl, S., 1 Sep 2016, In: Environmental Science & Technology. 50, 19, p. 10485-10493Research output: Contribution to journal › Journal article › peer-review
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Continuous Chemistry in Ice Cores: Phosphorus, pH and the Photolysis of Humic Like Substances
Kjær, Helle Astrid, 2014, The Niels Bohr Institute, Faculty of Science, University of Copenhagen.Research output: Book/Report › Ph.D. thesis
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A portable lightweight in situ analysis (LISA) box for ice and snow analysis
Kjær, Helle Astrid, Lolk Hauge, L., Simonsen, M., Yoldi, Zuriñe, Koldtoft, Iben, Hörhold, M., Freitag, J., Kipfstuhl, S., Svensson, Anders & Vallelonga, P., 2021, In: Cryosphere. 15, 8, p. 3719-3730Research output: Contribution to journal › Journal article › peer-review
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Canadian forest fires, Icelandic volcanoes and increased local dust observed in six shallow Greenland firn cores
Kjær, Helle Astrid, Zens, P., Black, S., Lund, K. H., Svensson, Anders & Vallelonga, P., 10 Oct 2022, In: Climate of the Past. 18, 10, p. 2211-2230 20 p.Research output: Contribution to journal › Journal article › peer-review
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Past perspectives on the present era of abrupt Arctic climate change
Jansen, E., Christensen, Jens Hesselbjerg, Dokken, T., Nisancioglu, K. H., Vinther, Bo Møllesøe, Capron, E., Guo, C., Jensen, M. F., Langen, P. L., Pedersen, R. A., Yang, S., Bentsen, M., Kjær, Helle Astrid, Sadatzki, H., Sessford, E. & Stendel, M., 1 Aug 2020, In: Nature climate change. 10, 8, p. 714-721 8 p.Research output: Contribution to journal › Journal article › peer-review
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Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS
Hvidberg, Christine Schøtt, Grinsted, Aslak, Dahl-Jensen, Dorthe, Khan, S. A., Kusk, A., Andersen, Jonas Kvist, Neckel, N., Solgaard, Anne Munck, Karlsson, N. B., Kjær, Helle Astrid & Vallelonga, P., 22 Oct 2020, In: Cryosphere. 14, 10, p. 3487-3502 16 p.Research output: Contribution to journal › Journal article › peer-review
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Continuous flow analysis of the Mount Brown South ice core
Harlan, Meg, Kjær, Helle Astrid, Vance, T., Vallelonga, P., Gkinis, Vasileios, Blunier, Thomas, Svensson, Anders, Moy, A., Plummer, C., Jackson, S., Peensoo, K. & Campo, A. D., 9 Apr 2021, 1 p. Copernicus/EGU.Research output: Other contribution › Research
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Accelerating ice flow at the onset of the Northeast Greenland Ice Stream
Grinsted, Aslak, Hvidberg, Christine Schøtt, Lilien, D. A., Rathmann, Nicholas Mossor, Karlsson, N. B., Gerber, T., Kjær, Helle Astrid, Vallelonga, P. & Dahl-Jensen, Dorthe, 23 Sep 2022, In: Nature Communications. 13, 1, 4 p., 5589.Research output: Contribution to journal › Journal article › peer-review
ID: 33355865
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On the occurrence of annual layers in Dome Fuji ice core early Holocene ice
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Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene
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Rapid increase in atmospheric iodine levels in the North Atlantic since the mid-20th century
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