Helle Astrid Kjær
Associate Professor
Physics of Ice, Climate and Earth
Tagensvej 16
2200 København N.
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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 › Research › peer-review
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A 2700-year annual timescale and accumulation history for an ice core from Roosevelt Island, West Antarctica
Winstrup, M., Vallelonga, P., Kjaer, H. A., Fudge, T. J., Lee, J. E., Riis, M. H., Edwards, R., Bertler, N. A. N., Blunier, T., Brook, E. J., Buizert, C., Ciobanu, G., Conway, H., Dahl-Jensen, D., Ellis, A., Emanuelsson, B. D., Hindmarsh, R. C. A., Keller, E. D., Kurbatov, A. V., Mayewski, P. A. & 7 others, , 10 Apr 2019, In: Climate of the Past. 15, 2, p. 751-779 29 p.Research output: Contribution to journal › Journal article › Research › peer-review
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A High-Resolution Continuous Flow Analysis System for Polar Ice Cores
Dallmayr, R., Goto-Azuma, K., Kjær, Helle Astrid, Azuma, N., Takata, M., Schüpbach, S. & Hirabayashi, M., 2016, In: Bulletin of Glaciological Research. 34, p. 11-20Research output: Contribution to journal › Journal article › Research › peer-review
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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 › Research › peer-review
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A novel approach to process brittle ice for continuous flow analysis of stable water isotopes
Pyne, R. L., Keller, E. D., Canessa, S., Bertler, N. A., Pyne, A. R., Pyne, A. R., Mandeno, D., Vallelonga, P. T., Semper, S., Kjær, Helle Astrid, Hutchison, E. & Baisden, W. T., 16 Mar 2018, In: Journal of Glaciology. 64, 243, p. 1-11Research output: Contribution to journal › Journal article › Research › 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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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 › Research › peer-review
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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 › Research › peer-review
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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 › Research › peer-review
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Afslørende kemi i Grønlands og Antarktis' iskerner
Svensson, Anders & Kjær, Helle Astrid, 1 Jun 2018, In: Dansk Kemi. 9, p. 18-21 3 p.Research output: Contribution to journal › Journal article › Research › peer-review
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An Age Scale for the First Shallow (Sub-)Antarctic Ice Core from Young Island, Northwest Ross Sea
Moser, D. E., Jackson, S., Kjær, Helle Astrid, Markle, B., Ngoumtsa, E., Pedro, J. B., Segato, D., Spolaor, A., Tetzner, D., Vallelonga, P. & Thomas, E. R., Sep 2021, In: Geosciences. 11, 9, 18 p., 368.Research output: Contribution to journal › Journal article › Research › 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 › Research › peer-review
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An annually resolved chronology for the Mount Brown South ice cores, East Antarctica
Vance, T. R., Abram, N. J., Criscitiello, A. S., Crockart, C. K., Decampo, A., Favier, V., Gkinis, Vasileios, Harlan, Meg, Jackson, S. L., Kjær, Helle Astrid, Long, C. A., Nation, M. K., Plummer, C. T., Segato, D., Spolaor, A. & Vallelonga, P. T., 24 Apr 2024, In: Climate of the Past. 20, 4, p. 969-990 22 p.Research output: Contribution to journal › Journal article › Research › peer-review
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Antarctic evidence for an abrupt northward shift of the Southern Hemisphere westerlies at 32 ka BP
Venugopal, A. U., Bertler, N. A. N., Severinghaus, J. P., Brook, E. J., Cortese, G., Lee, J. E., Blunier, Thomas, Mayewski, P. A., Kjær, Helle Astrid, Carter, L., Weber, M. E., Levy, R. H., Pyne, R. L. & Vandergoes, M. J., 5 Sep 2023, In: Nature Communications. 14, 1, 8 p., 5432.Research output: Contribution to journal › Journal article › Research › peer-review
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Arctic mercury flux increased through the Last Glacial Termination with a warming climate
Segato, D., Saiz-Lopez, A., Mahajan, A. S., Wang, F., Corella, J. P., Cuevas, C. A., Erhardt, T., Jensen, C. M., Zeppenfeld, C., Kjær, Helle Astrid, Turetta, C., Cairns, W. R. L., Barbante, C. & Spolaor, A., 4 May 2023, In: Nature Geoscience. 16, p. 439-445 9 p.Research output: Contribution to journal › Journal article › Research › peer-review
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Assessing surface-exposed old ice along the Greenland Ice Sheet margin as an analogue for the Northern Polar Layered Deposits on Mars
Yoldi, Zuriñe, Hvidberg, Christine Schøtt, Svensson, Anders, Vallelonga, P. T. & Kjær, Helle Astrid, 8 Oct 2020, 3 p. Göttingen, Germany : Europlanet Science Congress.Research output: Other contribution › Research
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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Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period
Svensson, A., Dahl-Jensen, D., Steffensen, J. P., Blunier, T., Rasmussen, S. O., Vinther, B. M., Vallelonga, P. T., Capron, E., Gkinis, V., Cook, E., Kjær, H. A., Muscheler, R., Kipfstuhl, S., Wilhelms, F., Stocker, T. F., Fischer, H., Adolphi, F., Erhardt, T., Sigl, M., Landais, A. & 6 others, , 19 Aug 2020, In: Climate of the Past. 16, p. 1565-1580 15 p.Research output: Contribution to journal › Journal article › Research › 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 › Research › peer-review
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Climate changes modulated the history of Arctic iodine during the Last Glacial Cycle
Corella, J. P., Maffezzoli, N., Spolaor, A., Vallelonga, P., Cuevas, C. A., Scoto, F., Müller, J., Vinther, Bo Møllesøe, Kjær, Helle Astrid, Cozzi, G., Edwards, R., Barbante, C. & Saiz-Lopez, A., 2022, In: Nature Communications. 13, 88.Research output: Contribution to journal › Journal article › 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
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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 › 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 › Research › 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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Determination of 129I in Arctic snow by a novel analytical approach using IC-ICP-SFMS
Ezerinskis, Z., Spolaor, A., Kirchgeorg, T., Cozzi, G., Vallelonga, P., Kjær, Helle Astrid, Sapolaite, J., Barbante, C. & Druteikiene, R., 10 Jan 2014, In: Journal of Analytical Atomic Spectrometry. 29, 10, p. 1827-1834Research output: Contribution to journal › Journal article › Research › 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
Research output: Contribution to journal › Journal article › Research › peer-review
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138
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Rapid increase in atmospheric iodine levels in the North Atlantic since the mid-20th century
Research output: Contribution to journal › Journal article › Research › peer-review
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