Helle Astrid Kjær
Associate Professor
Physics of Ice, Climate and Earth
Tagensvej 16
2200 København N.
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Initial results from geophysical surveys and shallow coring of the Northeast Greenland Ice Stream (NEGIS)
Vallelonga, P. T., Christianson, K., Alley, R. B., Anandakrishnan, S., Dahl-Jensen, D., Gkinis, V., Holme, C. T., Jacobel, R. W., Karlsson, N. B., Keisling, B. A., Kipfstuhl, S., Kjær, H. A., Kristensen, M. E., Muto, A., Peters, L. E., Popp, T. J., Riverman, K. L., Svensson, A., Tibuleac, C., Vinther, B. M. & 2 others, , 10 Jan 2014, In: The Cryosphere Discussions. 8, p. 1275-1287Research output: Contribution to journal › Journal article › 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 › peer-review
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Holocene atmospheric iodine evolution over the North Atlantic
Corella, J. P., Maffezzoli, N., Cuevas, C. A., Vallelonga, P., Spolaor, A., Cozzi, G., Muller, J., Vinther, Bo Møllesøe, Barbante, C., Kjær, Helle Astrid, Edwards, R. & Saiz-Lopez, A., 18 Dec 2019, In: Climate of the Past. 15, 6, p. 2019-2030Research output: Contribution to journal › Journal article › peer-review
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High-resolution aerosol data from the top 3.8 kyr of the East Greenland Ice coring Project (EGRIP) ice core
Erhardt, T., Jensen, C. M., Adolphi, F., Kjær, H. A., Dallmayr, R., Twarloh, B., Behrens, M., Hirabayashi, M., Fukuda, K., Ogata, J., Burgay, F., Scoto, F., Crotti, I., Spagnesi, A., Maffezzoli, N., Segato, D., Paleari, C., Mekhaldi, F., Muscheler, R., Darfeuil, S. & 1 others, , 17 Nov 2023, In: Earth System Science Data. 15, 11, p. 5079-5091 13 p.Research output: Contribution to journal › Journal article › peer-review
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High-resolution aerosol concentration data from the Greenland NorthGRIP and NEEM deep ice cores
Erhardt, T., Bigler, M., Federer, U., Gfeller, G., Leuenberger, D., Stowasser, O., Rothlisberger, R., Schupbach, S., Ruth, U., Twarloh, B., Wegner, A., Goto-Azuma, K., Kuramoto, T., Kjaer, H. A., Vallelonga, P. T., Siggaard-Andersen, M-L., Hansson, M. E., Benton, A. K., Fleet, L. G., Mulvaney, R. & 4 others, , 16 Mar 2022, In: Earth System Science Data. 14, 3, p. 1215-1231 17 p.Research output: Contribution to journal › Journal article › 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 › peer-review
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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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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 › peer-review
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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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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 › peer-review
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El Niño-Southern Oscillation signal in a new East Antarctic ice core, Mount Brown South
Crockart, C. K., Vance, T. R., Fraser, A. D., Abram, N. J., Criscitiello, A. S., Curran, M. A. J., Favier, V., Gallant, A. J. E., Kittel, C., Kjær, Helle Astrid, Klekociuk, A. R., Jong, L. M., Moy, A. D., Plummer, C. T., Vallelonga, P. T., Wille, J. & Zhang, L., 9 Sep 2021, In: Climate of the Past. 17, 5, p. 1795-1818 24 p.Research output: Contribution to journal › Journal article › peer-review
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Eemian interglacial reconstructed from a Greenland folded ice core
Dahl-Jensen, D., Albert, M. R., Aldahan, A., Azuma, N., Balslev-Clausen, D. M., Baumgartner, M., Berggren, A-M., Bigler, M., Binder, T., Blunier, T., Bourgeois, J. C., Brook, E. J., Buchardt, S. L., Buizert, C., Capron, E., Chappellaz, J., Chung, J., Clausen, H. B., Cvijanovic, I., Davies, S. M. & 113 others, , 24 Jan 2013, In: Nature. 493, 7433, p. 489-494 6 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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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 › peer-review
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Duration of Greenland Stadial 22 and ice-gas Δage from counting of annual layers in Greenland NGRIP ice core
Vallelonga, P. T., Bertagna, G., Blunier, Thomas, Kjær, Helle Astrid, Popp, T. J., Rasmussen, Sune Olander, Steffensen, Jørgen Peder, Stowasser, C., Svensson, Anders, Warming, E., Winstrup, M., Bigler, M. & Kipfstuhl, S., 20 Nov 2012, In: Climate of the Past. 8, 6, p. 1839-1847 8 p.Research output: Contribution to journal › Journal article › peer-review
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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 › 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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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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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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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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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 › 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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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 › 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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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
ID: 33355865
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225
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On the occurrence of annual layers in Dome Fuji ice core early Holocene ice
Research output: Contribution to journal › Journal article › peer-review
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174
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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 › 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 › peer-review
Published