Helle Astrid Kjær
Associate Professor
Physics of Ice, Climate and Earth
Tagensvej 16
2200 København N.
- 2024
- Published
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
- 2023
- Published
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 › Research › peer-review
- Published
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
- Published
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
- 2022
- Published
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
- Published
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
- Published
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
- Published
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
- Published
Melt in the Greenland EastGRIP ice core reveals Holocene warm events
Westhoff, Julien, Sinnl, Giulia, Svensson, Anders, Freitag, J., Kjær, Helle Astrid, Vallelonga, P. T., Vinther, Bo Møllesøe, Kipfstuhl, S., Dahl-Jensen, Dorthe & Weikusat, I., 10 May 2022, In: Climate of the Past. 18, 5, p. 1011-1034 24 p.Research output: Contribution to journal › Journal article › Research › peer-review
- Published
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 › Research › peer-review
- Published
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
- Published
Role of mineral dust in the nitrate preservation during the glacial period: Insights from the RICE ice core
Venugopal, A. U., Bertler, N. A. N., Pyne, R. L., Kjær, Helle Astrid, Winton, V. H. L., Mayewski, P. A. & Cortese, G., 1 Feb 2022, In: Global and Planetary Change. 209, 10 p., 103745.Research output: Contribution to journal › Journal article › Research › peer-review
- Published
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
- Published
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
- 2021
- Published
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
- Published
Sea-ice reconstructions from bromine and iodine in ice cores
Vallelonga, P., Maffezzoli, N., Saiz-Lopez, A., Scoto, F., Kjær, Helle Astrid & Spolaor, A., 1 Oct 2021, In: Quaternary Science Reviews. 269, 41 p., 107133.Research output: Contribution to journal › Review › Research › peer-review
- Published
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 › Research › peer-review
- Published
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
- Published
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
- Published
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
- Published
Melt in the Greenland EastGRIP ice core reveals Holocene warming events
Westhoff, Julien, Sinnl, Giulia, Svensson, Anders, Freitag, J., Kjær, Helle Astrid, Vallelonga, P., Vinther, Bo Møllesøe, Kipfstuhl, S., Dahl-Jensen, Dorthe & Weikusat, I., 16 Jul 2021, 36 p. Copernicus/EGU.Research output: Other contribution › Research
- Published
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
- Published
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
- Published
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
- Published
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
ID: 33355865
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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 › Research › peer-review
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177
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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
Published