C. U. Hammer

16.4k citations

74 papers · 11.5k indexed · 5 hit papers · h-index 40

Impact in

Atmospheric Science top 0.05%
- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Climate change and permafrost
Earth-Surface Processes top 0.2%
- Geological formations and processes

Papers in ⓘ

Atmospheric Science 64
- Geology and Paleoclimatology Research 50
- Cryospheric studies and observations 43
- Climate change and permafrost 7
Geochemistry and Petrology 8
- Groundwater and Isotope Geochemistry 8

Co-authors: W. Dansgaard (14 shared papers)Henrik Clausen (19 shared papers)S. J. Johnsen (18 shared papers)N. Gundestrup (14 shared papers)J. P. Steffensen (10 shared papers)H. B. Clausen (13 shared papers)Dorthe Dahl‐Jensen (7 shared papers)Gérard C. Bond (2 shared papers)
Journals: Nature (14 papers)Journal of Geophysical Research Atmospheres (12 papers)Journal of Glaciology (8 papers)Annals of Glaciology (7 papers)Science (4 papers)
Partner nations: Denmark United States France

In The Last Decade

C. U. Hammer

74 papers receiving 10.5k citations

Hit Papers

5 papers align trajectories log scale

Asynchrony of Antarctic and Greenland climate change during the last glacial period 1998 · 553 citations

What are hit papers?

Hit papers significantly outperform the citation benchmark for their cohort. A paper qualifies if any of the following hold:

it has ≥500 total citations;
it reaches ≥1.5× the top-1% citation threshold for papers in the same subfield and year (the threshold is the minimum needed to enter the top 1%, not the average within it);
it reaches the top citation threshold in at least one of its specific research topics.

1998 Nature
1996 Science
1993 Nature
1992 Nature
1980 Nature

Peers

Countries citing papers authored by C. U. Hammer

Since Specialization

Citations

This map shows the geographic impact of C. U. Hammer's research. It shows the number of citations coming from papers published by authors working in each country. You can also color the map by specialization and compare the number of citations received by C. U. Hammer with the expected number of citations based on a country's size and research output (numbers larger than one mean the country cites C. U. Hammer more than expected).

Fields of papers citing papers by C. U. Hammer

Since Specialization

Physical SciencesHealth SciencesLife SciencesSocial Sciences

This network shows the impact of papers produced by C. U. Hammer. Nodes represent research fields, and links connect fields that are likely to share authors. Colored nodes show fields that tend to cite the papers produced by C. U. Hammer. The network helps show where C. U. Hammer may publish in the future.

Co-authors

The 25 scholars most cited alongside C. U. Hammer, linked wherever they have co-authored with each other. Click a name or a connecting line to browse the papers they share.

Border = papers with C. U. Hammer Line = papers co-authored together C. U. Hammer links everyone, so they are left out of the graph.

All Works

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20 of 20 papers shown

Showing the 20 most-cited of 74 papers — load more, or switch the sort, to bring in the rest.

#	Work
1	Evidence for general instability of past climate from a 250-kyr ice-core record Nature ·W. Dansgaard, S. J. Johnsen, Henrik Clausen, Dorthe Dahl‐Jensen, N. Gundestrup, C. U. Hammer, Christine S. Hvidberg, J. P. Steffensen, A. E. Sveinbjörnsdottír, J. Jouzel, Gérard C. Bond Hit paper breakdown →	1993	3538
2	Irregular glacial interstadials recorded in a new Greenland ice core Nature ·S. J. Johnsen, Henrik Clausen, W. Dansgaard, Katrin Führer, N. Gundestrup, C. U. Hammer, P. Iversen, J. Jouzel, B. Stauffer, J. P. Steffensen Hit paper breakdown →	1992	1154
3	Asynchrony of Antarctic and Greenland climate change during the last glacial period Nature ·Thomas Blunier, J. Chappellaz, Jakob Schwander, A. Dällenbach, B. Stauffer, Thomas F. Stocker, Dominique Raynaud, J. Jouzel, H. B. Clausen, C. U. Hammer, S. J. Johnsen Hit paper breakdown →	1998	553
4	Greenland ice sheet evidence of post-glacial volcanism and its climatic impact Nature ·C. U. Hammer, H. B. Clausen, W. Dansgaard Hit paper breakdown →	1980	509
5	Synchronized Terrestrial Atmospheric Deglacial Records Around the North Atlantic Science ·Svante Björck, Bernd Kromer, S. J. Johnsen, Ole Bennike, Dan Hammarlund, Geoffrey Lemdahl, Göran Possnert, Tine L. Rasmussen, Barbara Wohlfarth, C. U. Hammer, Marco Spurk Hit paper breakdown →	1996	485
6	Ash layers from Iceland in the Greenland GRIP ice core correlated with oceanic and land sediments Earth and Planetary Science Letters ·Karl Grönvold, N. Óskarsson, S. J. Johnsen, Henrik Clausen, C. U. Hammer, Gérard C. Bond, Édouard Bard	1995	425
7	A New Greenland Deep Ice Core Science ·W. Dansgaard, H. B. Clausen, N. Gundestrup, C. U. Hammer, S. Johnsen, P. M. Kristinsdottir, Niels Reeh	1982	411
8	The δ¹⁸O record along the Greenland Ice Core Project deep ice core and the problem of possible Eemian climatic instability Journal of Geophysical Research Atmospheres ·S. J. Johnsen, Henrik Clausen, W. Dansgaard, N. Gundestrup, C. U. Hammer, Uffe Brandt Andersen, K. K. Andersen, Christine S. Hvidberg, Dorthe Dahl‐Jensen, J. P. Steffensen, Hitoshi Shoji, Árný E. Sveinbjörnsdóttir, J. W. C. White, Jean Jouzel, David Fisher	1997	365
9	Acidity of Polar Ice Cores in Relation to Absolute Dating, Past Volcanism, and Radio–Echoes Journal of Glaciology ·C. U. Hammer	1980	268
10	Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records Quaternary Research ·Valérie Masson‐Delmotte, Françoise Vimeux, Jean Jouzel, Vin Morgan, Marc Delmotte, Philippe Ciais, C. U. Hammer, S. J. Johnsen, V. Lipenkov, Ellen Mosley‐Thompson, Jean‐Robert Petit, Eric J. Steig, M. Stiévenard, Rein Vaikmäe	2000	256
11	Dating of Greenland Ice Cores by Flow Models, Isotopes, Volcanic Debris, and Continental Dust Journal of Glaciology ·C. U. Hammer, H. B. Clausen, W. Dansgaard, N. Gundestrup, S. J. Johnsen, Niels Reeh	1978	210
12	Beryllium 10 in the Greenland Ice Core Project ice core at Summit, Greenland Journal of Geophysical Research Atmospheres ·F. Yiou, G. M. Raisbeck, S. Baumgartner, J. Beer, C. U. Hammer, S. J. Johnsen, J. Jouzel, Peter W. Kubik, J. Lestringuez, M. Stiévenard, M. Suter, Pascal Yiou	1997	208
13	Electrical conductivity measurements from the GISP2 and GRIP Greenland ice cores Nature ·K. C. Taylor, C. U. Hammer, Richard B. Alley, H. B. Clausen, Dorthe Dahl‐Jensen, Anthony J. Gow, N. Gundestrup, J. Kipfstuh, John C. Moore, E. D. Waddington	1993	205
14	Climatic changes, Norsemen and modern man Nature ·W. Dansgaard, S. J. Johnsen, Niels Reeh, N. Gundestrup, H. B. Clausen, C. U. Hammer	1975	175
15	Past volcanism revealed by Greenland Ice Sheet impurities Nature ·C. U. Hammer	1977	170
16	A comparison of the volcanic records over the past 4000 years from the Greenland Ice Core Project and Dye 3 Greenland ice cores Journal of Geophysical Research Atmospheres ·Henrik Clausen, C. U. Hammer, Christine S. Hvidberg, Dorthe Dahl‐Jensen, J. P. Steffensen, J. Kipfstuhl, Michel Legrand	1997	141
17	The Laki and Tambora Eruptions as Revealed in Greenland Ice Cores from 11 Locations Annals of Glaciology ·H. B. Clausen, C. U. Hammer	1988	126
18	Primary aerosol (sea salt and soil dust) deposited in Greenland ice during the last climatic cycle: Comparison with east Antarctic records Journal of Geophysical Research Atmospheres ·M. de Angelis, J. P. Steffensen, Michel Legrand, Henrik Clausen, C. U. Hammer	1997	115
19	The Minoan eruption of Santorini in Greece dated to 1645 BC? Nature ·C. U. Hammer, H. B. Clausen, Walter Friedrich, Henrik Tauber	1987	111
20	New ice core evidence for a volcanic cause of the A.D. 536 dust veil Geophysical Research Letters ·L. B. Larsen, Bo Vinther, Keith R. Briffa, Thomas Melvin, Henrik Clausen, P. D. Jones, M.‐L. Siggaard‐Andersen, C. U. Hammer, M. Eronen, Håkan Grudd, Björn E. Gunnarson, Rashit Hantemirov, Mukhtar M. Naurzbaev, Kurt Nicolussi	2008	111

About C. U. Hammer

C. U. Hammer is a scholar working on Atmospheric Science, Geochemistry and Petrology, Ecology, Environmental Chemistry and Astronomy and Astrophysics, having authored 74 papers that have together received 11.5k indexed citations. Recurring topics across this work include Geology and Paleoclimatology Research (50 papers), Cryospheric studies and observations (43 papers), Isotope Analysis in Ecology (15 papers), Polar Research and Ecology (13 papers), Methane Hydrates and Related Phenomena (9 papers), Planetary Science and Exploration (9 papers), Groundwater and Isotope Geochemistry (8 papers) and Climate change and permafrost (7 papers). The work is most often cited by research in Atmospheric Science (10.4k citations), Earth-Surface Processes (1.8k citations), Paleontology (1.7k citations), Anthropology (2.1k citations) and Environmental Chemistry (1.6k citations). C. U. Hammer has collaborated with scholars based in Denmark, United States and France. Frequent co-authors include W. Dansgaard, Henrik Clausen, S. J. Johnsen, N. Gundestrup, J. P. Steffensen, H. B. Clausen, Dorthe Dahl‐Jensen, Gérard C. Bond, Christine S. Hvidberg and A. E. Sveinbjörnsdottír. Their work appears in journals such as Nature, Journal of Geophysical Research Atmospheres, Journal of Glaciology, Annals of Glaciology and Science.

Rankless uses publication and citation data sourced from OpenAlex, an open and comprehensive bibliographic database. While OpenAlex provides broad and valuable coverage of the global research landscape, it—like all bibliographic datasets—has inherent limitations. These include incomplete records, variations in author disambiguation, differences in journal indexing, and delays in data updates. As a result, some metrics and network relationships displayed in Rankless may not fully capture the entirety of a scholar's output or impact.

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