Helle Astrid Kjær

Helle Astrid Kjær

Associate Professor


  1. 2023
  2. 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, Fischer, H., 17 Nov 2023, In: Earth System Science Data. 15, 11, p. 5079-5091 13 p.

    Research output: Contribution to journalJournal articlepeer-review

  3. 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 journalJournal articlepeer-review

  4. 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 journalJournal articlepeer-review

  5. 2022
  6. 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 journalJournal articlepeer-review

  7. 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, 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 articlepeer-review

  8. 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 journalJournal articlepeer-review

  9. 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 journalJournal articlepeer-review

  10. 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 journalJournal articlepeer-review

  11. 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 articlepeer-review

  12. 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 journalEditorialpeer-review

  13. 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 journalJournal articlepeer-review

  14. 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 articlepeer-review

  15. 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 articlepeer-review

  16. 2021
  17. 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 articlepeer-review

  18. 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

  19. 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 articlepeer-review

  20. 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 articlepeer-review

  21. 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

  22. 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

  23. Published
  24. 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 articlepeer-review

  25. 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 articlepeer-review

  26. 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 articlepeer-review

  27. 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 journalReviewpeer-review

  28. 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

Previous 1 2 3 Next

ID: 33355865