Helle Astrid Kjær

Helle Astrid Kjær

Associate Professor


  1. 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 articlepeer-review

  2. 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

  3. 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

  4. Published

    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. 2031-2051

    Research output: Contribution to journalJournal articlepeer-review

  5. 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

  6. 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

  7. Published
  8. 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

  9. Published

    Laboratory supervision of MSc projects -Qualitative interviews, thematic analysis, and recommendations for the supervisor

    Kjær, Helle Astrid, 23 May 2018, Improving University Science Teaching and Learning Pedagogical Projects 2018. Institut for Naturfagenes Didaktik ed. København, Danmark: Københavns Universitet, Vol. 12. p. 91-105 (Improving University Science Teaching and Learning - Pedagogical Projects).

    Research output: Chapter in Book/Report/Conference proceedingBook chapterEducation

  10. 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

  11. Published

    Iskerner-et indblik i fortidens klimaforandringer

    Kjær, Helle Astrid & Balslev-Clausen, D., 2 Apr 2011, Aspekter af dansk kemi i det 20. og 21. århundrede. 1 ed. København: Kemi Forlaget, p. 65-70 5 p.

    Research output: Chapter in Book/Report/Conference proceedingBook chapterCommunication

  12. 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

  13. Published

    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, 20

    Research output: Contribution to journalJournal articlepeer-review

  14. Published

    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, 1526

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  15. Published

    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, 1524

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  16. 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 proceedingReport chapterResearch

  17. Published

    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. 12325-12332

    Research output: Contribution to journalJournal articlepeer-review

  18. Published

    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. 10485-10493

    Research output: Contribution to journalJournal articlepeer-review

  19. Published

    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/ReportPh.D. thesis

  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

    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

  22. 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 articlepeer-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, Jonas Kvist, Neckel, N., Solgaard, Anne Munck, 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 articlepeer-review

  24. 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

  25. 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

ID: 33355865