Helle Astrid Kjær

Helle Astrid Kjær

Project Coordinator


  1. 2022
  2. 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., Kjær, Helle Astrid, Vallelonga, P. T., Siggaard-Andersen, M., Hansson, M. E., Benton, A. K., Fleet, L. G., Mulvaney, R., Thomas, E. R., Abram, N., Stocker, T. F. & Fischer, H., 16 Mar 2022, In: Earth System Science Data. 14, 3, p. 1215-1231 17 p.

    Research output: Contribution to journalJournal articleResearchpeer-review

  3. 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, Jia-mei, 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 journalJournal articleResearchpeer-review

  4. 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 journalJournal articleResearchpeer-review

  5. 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 journalEditorialResearchpeer-review

  6. 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 journalJournal articleResearchpeer-review

  7. 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 journalJournal articleResearchpeer-review

  8. 2021
  9. 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 journalJournal articleResearchpeer-review

  10. 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 contributionResearch

  11. 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 journalJournal articleResearchpeer-review

  12. Published

    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. 3719-3730

    Research output: Contribution to journalJournal articleResearchpeer-review

  13. 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 contributionResearch

  14. 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 2021

    Research output: Other contributionResearch

  15. Published
  16. 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 journalJournal articleResearchpeer-review

  17. 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 journalJournal articleResearchpeer-review

  18. 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 journalJournal articleResearchpeer-review

  19. 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 journalReviewResearchpeer-review

  20. 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 contributionResearch

  21. 2020
  22. Published

    New data from the 40 year old Dye3 core

    Blunier, Thomas, Venkatesh, J., Soestmeyer, D. A., Liisberg, J. B., Rhodes, R., Menking, J. A., Severinghaus, J. P., Harlan, Meg, Kjær, Helle Astrid & Vallelonga, P., 23 Mar 2020. 1 p.

    Research output: Contribution to conferenceConference abstract for conferenceResearchpeer-review

  23. Published

    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, J. K., Neckel, N., Solgaard, A., Karlsson, N. B., Kjær, Helle Astrid & Vallelonga, P., 22 Oct 2020, In: Cryosphere. 14, 10, p. 3487-3502 16 p.

    Research output: Contribution to journalJournal articleResearchpeer-review

  24. Published

    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 journalJournal articleResearchpeer-review

  25. Published

    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 journalJournal articleResearchpeer-review

  26. Published

    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 journalJournal articleResearchpeer-review

  27. Published

    Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period

    Svensson, Anders, Dahl-Jensen, Dorthe, Steffensen, Jørgen Peder, Blunier, Thomas, Rasmussen, Sune Olander, Vinther, Bo Møllesøe, Vallelonga, P. T., Capron, E., Gkinis, Vasileios, Cook, Eliza, Kjær, Helle Astrid, Muscheler, R., Kipfstuhl, S., Wilhelms, F., Stocker, T. F., Fischer, H., Adolphi, F., Erhardt, T., Sigl, M., Landais, A., Parrenin, F., Buizert, C., McConnell, J. R., Severi, M., Mulvaney, R. & Bigler, M., 19 Aug 2020, In: Climate of the Past. 16, p. 1565-1580 15 p.

    Research output: Contribution to journalJournal articleResearchpeer-review

  28. Published

    Supplementary material to "Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period"

    Svensson, Anders, Dahl-Jensen, Dorthe, Steffensen, Jørgen Peder, Blunier, Thomas, Rasmussen, Sune Olander, Vinther, Bo Møllesøe, Vallelonga, P., Capron, E., Gkinis, Vasileios, Cook, Eliza, Kjær, Helle Astrid, Muscheler, R., Kipfstuhl, S., Wilhelms, F., Stocker, T. F., Fischer, H., Adolphi, F., Erhardt, T., Sigl, M., Landais, A., Parrenin, F., Buizert, C., McConnell, J. R., Severi, M., Mulvaney, R. & Bigler, M., 6 Apr 2020, 32 p. Copernicus/EGU.

    Research output: Other contributionResearch

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ID: 33355865