Helle Astrid Kjær
Associate Professor
Physics of Ice, Climate and Earth
Tagensvej 16
2200 København N.
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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 › 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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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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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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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 › Research › 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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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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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 › Research › 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 › Research › 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 › 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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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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Greenland 2012 melt event effects on CryoSat-2 radar altimetry
Nilsson, J., Vallelonga, P., Simonsen, S. B., Sorensen, L. S., Forsberg, R., Dahl-Jensen, Dorthe, Hirabayashi, M., Goto-Azuma, K., Hvidberg, Christine Schøtt, Kjær, Helle Astrid & Satow, K., 28 May 2015, In: Geophysical Research Letters (Online). 42, 10, p. 3919-3926Research output: Contribution to journal › Journal article › Research › peer-review
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Ice core evidence for a 20th century increase in surface mass balance in coastal Dronning Maud Land, East Antarctica
Philippe, M., Tison, J., Fjosne, K., Hubbard, B., Kjær, Helle Astrid, Lenaerts, J. T. M., Drews, R., Sheldon, S. G., De Bondt, K., Claeys, P. & Pattyn, F., 2016, In: Cryosphere. 10, 5, p. 2501-2516 16 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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Rapid reductions and millennial-scale variability in Nordic Seas sea ice cover during abrupt glacial climate changes
Sadatzki, H., Maffezzoli, N., Dokken, T. M., Simon, M. H., Berben, S. M. P., Fahl, K., Kjær, Helle Astrid, Spolaor, A., Stein, R., Vallelonga, P., Vinther, Bo Møllesøe & Jansen, E., 24 Nov 2020, In: Proceedings of the National Academy of Sciences of the United States of America. 117, 47, p. 29478-29486 9 p.Research output: Contribution to journal › Journal article › Research › peer-review
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Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene
Schupbach, S., Fischer, H., Bigler, M., Erhardt, T., Gfeller, G., Leuenberger, D., Mini, O., Mulvaney, R., Abram, N. J., Fleet, L., Frey, M. M., Thomas, E., Svensson, A., Dahl-Jensen, D., Kettner, E., Kjaer, H., Seierstad, I., Steffensen, J. P., Rasmussen, S. O., Vallelonga, P. & 30 others, , 16 Apr 2018, In: Nature Communications. 9, 1476.Research output: Contribution to journal › Journal article › Research › peer-review
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Sea ice fluctuations in the Baffin Bay and the Labrador Sea during glacial abrupt climate changes
Scoto, F., Sadatzki, H., Maffezzoli, N., Barbante, C., Gagliardi, A., Varin, C., Vallelonga, P., Gkinis, Vasileios, Dahl-Jensen, Dorthe, Kjær, Helle Astrid, Burgay, F., Saiz-Lopez, A., Stein, R. & Spolaor, A., 1 Nov 2022, In: Proceedings of the National Academy of Sciences of the United States of America. 119, 44, 9 p., 2203468119.Research output: Contribution to journal › Journal article › Research › peer-review
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Five thousand years of fire history in the high North Atlantic region: natural variability and ancient human forcing
Segato, D., Villoslada Hidalgo, M. D. C., Edwards, R., Barbaro, E., Vallelonga, P., Kjær, Helle Astrid, Simonsen, M., Vinther, Bo Møllesøe, Maffezzoli, N., Zangrando, R., Turetta, C., Battistel, D., Vesteinsson, O., Barbante, C. & Spolaor, A., 20 Jul 2021, In: Climate of the Past. 17, 4, p. 1533-1545 13 p.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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Particle shape accounts for instrumental discrepancy in ice core dust size distributions
Simonsen, M. F., Cremonesi, L., Baccolo, G., Bosch, S., Delmonte, B., Erhardt, T., Kjær, Helle Astrid, Potenza, M., Svensson, Anders & Vallelonga, P., 3 May 2018, In: Climate of the Past. 14, 5, p. 601-608Research output: Contribution to journal › Journal article › Research › peer-review
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East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat.
Simonsen, M. F., Baccolo, G., Blunier, Thomas, Borunda, A., Delmonte, B., Frei, Robert, Goldstein, S., Grinsted, Aslak, Kjær, Helle Astrid, Sowers, T., Svensson, Anders, Vinther, Bo Møllesøe, Vladimirova, D., Winckler, G., Winstrup, M. & Vallelonga, P., 3 Oct 2019, In: Nature Communications. 10, 8 p., 4494.Research 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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176
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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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137
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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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