Cooperative Institute for Research in Environmental Sciences

Jennifer Kay Group

Jennifer Kay Group

Polar and atmospheric science

The poorly observed polar regions are changing rapidly and present many exciting research opportunities. Our group's research interests include coupled climate processes, cold clouds and precipitation, sea ice, climate forcing and feedbacks, and internal climate variability. The tools we apply include remote sensing observations, in situ observations, process models, coupled climate models, instrument simulators, and data assimilation. We work closely with scientists at the National Center for Atmospheric Research (NCAR, also located in Boulder) in the development and analysis of global coupled climate models.

I am an assistant professor in the Department of Atmospheric and Oceanic Sciences, a CIRES Fellow, and a co-chair of the CESM Polar Climate Working Group. Prior to coming to the University of Colorado at Boulder, I worked as a scientist in NCAR's Climate and Global Dynamics Division.  My publications are up-to-date on Google Scholar.

Please be in touch if you are interested in joining us in beautiful Boulder, Colorado.


"The emphasis on observation opens special avenues to discovery.  Discoveries, it seems, can be forced to occur in the future, as they often have in the past, by the deliberate making of observations of new phenomena or new frontiers." (from "The Incomplete Guide to the Art of Discovery" by Jack. E. Oliver, Professor Emeritus at Cornell University)

Current research projects:

1) Cloud influence on and response to Arctic sea ice loss
2) Microphysical and dynamical processes controlling extratropical cloud-climate feedbacks
3) Coupling between clouds and global-scale atmosphere and ocean circulation patterns
4) Dynamic and thermodynamic controls on extratropical precipitation changes in a warming world
5) Sea ice trends, variability, and predictability in both the Arctic and Antarctic
6) Processes controlling the Arctic inversion (with McGill)

Research tools/datasets developed and used by the Kay Group: 
1) CloudSat and CALIPSO spaceborne radar and lidar (cloud fraction dataset)
2) CESM Large Ensemble Project
3) CFMIP Observational Simulator Package (COSP) in CESM

Learn More About Climate video discussing our Arctic climate research.

2017 Highlights

  • Jen awarded 2017 Henry G. Houghton Award by the American Meteorological Society "For the innovative use of observations and global climate models to better understand the rapidly evolving climate of the polar regions"
  • ATOC Ph.D. candidate and Kay group member Ariel Morrison awarded a Chateaubriand Fellowship from the Embassy of France for her work on Arctic clouds and sea ice.  Ariel is spending Spring 2017 in Paris, France working with Professor Helene Chepfer at LMD/Ecole Polytechnique.  Bon Voyage!
  • ATOC Ph.D. candidate and Kay group member Vineel Yettella awarded a 2017 CIRES Graduate Student Research Award for his prediction work using the CESM Large Ensemble (joint with ATOC Professor Jeff Weiss). Congrats Vineel!!
  • Lucy Rieves (CU Undergraduate) will join the Kay group for the summer through the UROP program.  Lucy's summer research will focus on understanding the impacts of climate change on agriculture in the United States.  Welcome Lucy!!

2016 Highlights





Jennifer Kay Group in CIRES news

Polar Bear Season

CIRES heads to Canada for the annual gathering of polar bears
Biology and EcosystemsClimate and WeatherCryosphere

Revised/Submitted/In prep

Frey, W. R. and J. E. Kay (revised), The influence of extratropical cloud phase and amount feedbacks on climate sensitivity, Climate Dynamics.

Morrison, A. L., Kay, J. E., Chepfer, H. and R. Guzman (in prep), Arctic clouds and sea ice within the intermittent mask, Journal of Geophysical Research - Atmospheres

Bourdages, L., Kay, J. E., Tremblay, B. and A. Desmarais, (submitted), Seasonality of the Arctic temperature inversion and its dependence on sea ice, J. Climate

Goosse, H., Kay, J. E., Armour, K. C., Bodas-Salcedo, A., Chepfer, H., Docquier, D., Jonko, A., Kushner, P. J., Lecomte, O., Massonnet, F., Park, H., Pithan, F., Svensson, G., and M. Vancoppenolle (in prep), Beyond radiative feedbacks: a process-oriented perspective on climate feedbacks in polar regions,


Lacour, A., Chepfer, H., Stone, M., Shupe, M., Miller, N., Noel, V., Kay, J. E., and D. D. Turner (2017), Greenland clouds observed by CALIPSO: comparison with groundbased Summit observations, J. Climate, accepted

Guzman, R., H. Chepfer, V. Noel, T. Vaillant de Guélis, J. E. Kay, P. Raberanto, G. Cesana, M. A. Vaughan, and D. M. Winker (2017), Direct atmosphere opacity observations from CALIPSO provide new constraints on cloud-radiation interactions, J. Geophys. Res. Atmos., 122, doi:10.1002/2016JD025946.

Webb, M. J., Andrews, T., Bodas-Salcedo, A., Bony, S., Bretherton, C. S., Chadwick, R., Chepfer, H., Douville, H., Good, P., Kay, J. E., Klein, S. A., Marchand, R., Medeiros, B., Siebesma, A. P., Skinner, C. B., Stevens, B., Tselioudis, G., Tsushima, Y., and Watanabe, M., (2017), The Cloud Feedback Model Intercomparison Project (CFMIP) contribution to CMIP6, Geosci. Model Dev., 10, 359-384, doi:10.5194/gmd-10-359-2017.


Kay, J. E., Wall, C., Yettella, V., Medeiros, B. Hannay, C., P. Caldwell, and C. Bitz (2016), Global climate impacts of fixing the Southern Ocean shortwave radiation bias in the Community Earth System Model, J. Climate, 29:12, 4617–4636, doi:10.1175/JCLI-D-15-0358.1available here, Correction to Figure 9 units

Kay, J. E., Bourdages, L., Chepfer, H., Miller, N., Morrison, A., Yettella, V., and B. Eaton (2016), Evaluating and improving cloud phase in the Community Atmosphere Model version 5 using spaceborne lidar observations, Journal of Geophysical Research - Atmospheres, 121:8, 4162–4176, DOI: 10.1002/2015JD024699

Kay, J. E., L'Ecuyer, T., Chepfer, H., Loeb, N., Morrison, A. and G. Cesana (2016), Recent advances in Arctic cloud and climate research, Current Climate Change Reports, 2:159, DOI: 10.1007/s40641-016-0051-9

Yettella, V. and J. E. Kay (2016), How will precipitation change in extratropical cyclones as the planet warms?: Insights from a large initial condition climate model ensemble, Climate DynamicsDOI 10.1007/s00382-016-3410-2

Barnhart, K. R., Miller, C. R., Overeem, I., and J. E. Kay (2016), Mapping the future expansion of Arctic open water, Nature Climate Changedoi:10.1038/nclimate2848, Nature highlight

Jahn, A., Kay, J. E., Holland, M. M. and D. M. Hall (2016), How predictable is the timing of a summer ice-free Arctic?, Geophysical Research Letters, 43, doi: 10.1002/2016GL070067, CU Today article

Palerme, C., Genthon, C., Claud, C., Kay, J. E., Wood, N. B. and T. L'Ecuyer (2016), Evaluation of current and projected Antarctic precipitation in CMIP5 models, Climate Dynamics, DOI 10.1007/s00382-016-3071-1

Stephens, G. L., Haukuba, M. Z., Hawcroft, M., Haywood, J., Behrangi, A, Kay, J. E., and P. J. Webster (2016), The curious nature of the hemispheric symmetry of the Earth's water and energy balances, Current Climate Change Reportsdoi:10.1007/s40641-016-0043-9

Favrier, V. et al. including J. E. Kay (2016), Atmospheric drying as the main driver of dramatic glacier wastage in the southern Indian Ocean, Nature Scientific Reportsdoi:10.1038/srep32396  CNRS Press Release (in French)

Day, J. et al. including J. E. Kay (2016), The Abisko Polar Prediction School, BAMSDOI:

Baker, A. H. et al. including J. E. Kay (2016), Evaluating Lossy Data Compression on Climate Simulation Data within a Large Ensemble, Geoscientific Model Development, 9, 4381-4403, doi:10.5194/gmd-9-4381-2016


Kay, J. E., Deser, C., Phillips, A., Mai, A., Hannay, C., Strand, G., Arblaster, J., Bates, S., Danabasoglu, G., Edwards, J., Holland, M. Kushner, P., Lamarque, J.-F., Lawrence, D., Lindsay, K., Middleton, A., Munoz, E., Neale, R., Oleson, K., Polvani, L., and M. Vertenstein (2015), The Community Earth System Model (CESM) Large Ensemble Project: A Community Resource for Studying Climate Change in the Presence of Internal Climate Variability, Bulletin of the American Meteorological Society, 96, 1333–1349.  doi:10.1175/BAMS-D-13-00255.1.

Matus, A. V., L'Ecuyer, T. S., Kay, J. E., Hannay, C. and J-F. Lamarque, 2015: The Role of Clouds in Modulating Global Aerosol Direct Radiative Effects in Spaceborne Active Observations and the Community Earth System Model. J. Climate, 28, 2986–3003. doi:

Swart, N. C., Fyfe, J. C., Hawkins, E., Kay, J. E., and A. Jahn (2015), Influence of internal variability on Arctic sea-ice trends, Nature Climate Change, 5, 86-89, doi:10.1038/nclimate2483. Press Release Daily Camera Story


Kay, J. E., B. Medeiros, Y.-T. Hwang, A. Gettelman, J. Perket, and M. G. Flanner (2014), Processes controlling Southern Ocean shortwave climate feedbacks in CESM, Geophys. Res. Lett., 41, doi:10.1002/2013GL058315.

English, J. M., Kay, J. E., Gettelman, A., Liu, X., Wang, Y., Zhang, Y. and H. Chepfer, (2014), Contributions of clouds, surface albedos, and mixed-phase ice nucleation schemes to Arctic radiation biases in CAM5, J. Climate, doi:

Palerme, C., Kay, J. E., Genthon, C., L'Ecuyer, T., Wood, N. B., and Claud, C. (2014), How much snow falls on the Antarctic ice sheet?, The Cryosphere, 8, 1577-1587, doi:10.5194/tc-8-1577-2014.

Perket, J., Flanner, M. G. and J. E. Kay (2014), Diagnosing Shortwave Cryosphere Radiative Effect and 21st Century Evolution in CESM, J. Geophys. Res., doi: 10.1002/2013JD021139

Tilmes, S., Lamarque, J.-F., Jahn, A., Kay, J. E. and M. Holland (2014), Can regional climate engineering save the summer Arctic sea ice?, Geophys. Res. Lett., doi: 10.1002/2013GL058731


Kay, J. E. and T. L'Ecuyer (2013), Observational constraints on Arctic Ocean clouds and radiative fluxes during the early 21st century, J. Geophys. Res., 118, doi:10.1002/jgrd.50489.

Brady, E., Otto-Bliesner, B., Kay, J. E., and N. Rosenbloom (2013), Sensitivity to Glacial Forcing in the CCSM4, J. Climate, 26, 1901–1925, doi:

Gettelman, A., Kay, J. E., and J. T. Fasullo (2013), Spatial Decomposition of Climate Feedbacks in the Community Earth System Model. J. Climate, 26, 3544–3561, doi:

Holland, M. M., Blanchard-Wrigglesworth, E.Kay, J., and S. Vavrus (2013), Initial-value predictability of Antarctic sea ice in the Community Climate System Model 3, Geophys Res Lett., 40, 2121–2124, doi:10.1002/grl.50410.

Hurrell, J., Holland, M. M., Gent, P. R , Ghan, S., Kay, J. E., Kushner, P., Lamarque, J-F., Large, W., G., Lawrence, D., Lindsay, K., Lipscomb, W. H., Long, M., Mahowald, N., Marsh, D., Neale, R., Rasch, P., Vavrus, S., Vertenstein, M., Bader, D., Collins, W. D., Hack, J. J., Kiehl, J. and S. Marshall (2013), The Community Earth System Model: A Framework for Collaborative Research, Bull. Amer. Meteor. Soc., doi:

Meehl, G., Washington, W. M., Arblaster, J. M., Hu, A., Teng, H., Kay, J. E., Gettelman, A., Lawrence, D. M., Sanderson, B. M., and W. G. Strand (2013), Climate change projections in CESM1(CAM5) compared to CCSM4, J. Climate, doi:

Sand, M., Berntsen, T. K., Kay, J. E., Lamarque, J. F., Seland, Ø., and A. Kirkevåg (2013), The Arctic response to remote and local forcing of black carbon, Atmos. Chem. Phys., 13, 211-224, doi:10.5194/acp-13-211-2013.


Kay, J. E., Holland, M. M., Bitz, C., Blanchard-Wrigglesworth, E.,Gettelman, A., Conley, A., and D. Bailey (2012), The influence of local feedbacks and northward heat transport on the equilibrium Arctic climate response to increased greenhouse gas forcing in coupled climate models, J. Climate, 25, 5433-5450, doi:10.1175/JCLI-D-11-00622.1

Kay, J. E., Hillman, B., Klein, S., Zhang, Y., Medeiros, B., Gettelman, G., Pincus, R., Eaton, B., Boyle, J., Marchand, R. and T. Ackerman (2012), Exposing global cloud biases in the Community Atmosphere Model (CAM) using satellite observations and their corresponding instrument simulators, J. Climate, 25, 5190-5207, doi:

Cesana, G., Kay, J. E., Chepfer, H., English, J.M., and G. de Boer (2012), Ubiquitous low-level liquid-containing Arctic clouds: New observations and climate model constraints from CALIPSO-GOCCP, Geophys. Res. Lett., 39, L20804, doi:10.1029/2012GL053385.

Gettelman, A., Kay, J. E., and K. Shell (2012), The evolution of climate sensitivity and climate feedbacks in the Community Atmosphere Model, J. Climate, 25, 1453-1469, doi: 10.1175/JCLI-D-11-00197.1

de Boer, G., Chapman, W., Kay, J. E., Medeiros, B., and M. D. Shupe (2012), A characterization of the present-day Arctic atmosphere in CCSM4, J. Climate, 25, 2676–2695, doi: 10.1175/JCLI-D-11-00228.1

Jahn, A., K. Sterling, M.M. Holland, J.E. Kay, J.A. Maslanik, C.M. Bitz, D.A. Bailey, J. Stroeve, E.C. Hunke, W.H. Lipscomb, D.A. Pollak (2012), Late 20th century simulation of Arctic sea ice and ocean properties in the CCSM4, J. Climate, 25:5, 1431-1452, doi: 10.1175/JCLI-D-11-00201.1.

Stroeve, J. C., Serreze, M. C., Holland, M.M., Kay, J. E., Meier, W., and A. P. Barrett (2012), The Arctic's rapidly shrinking sea ice cover: A research synthesis, Climatic Change, 110, 3-4, 1005-1027, doi: 10.1007/s10584-011-0101-1

Bromwich, D. H., Nicolas, J. P., Hines, K., Kay, J. E., Key, E., Lazzara, M., Lubin, D. McFarquhar, G., Adams, N., Gorodetskaya, I., Grosvenor, D. P., Lachlan-Cope, T., and N. Van Lipzig (2012), Tropospheric clouds in Antarctica, Rev. Geophys., 50, RG1004, doi:10.1029/2011RG000363.

Jochum, M., Jahn, A., Peacock, S., Bailey, D., Fasullo, J., Kay, J. E., Levis, S. and B. Otto-Bliesner (2012), True to Milankovitch: Glacial Inception in the new Community Climate System Model, J. Climate, 25:7, 2226-2239, doi:

Raeder, K., Anderson, J. L., Collins, N., Hoar, T. J., Kay, J. E., Lauritzen, P. H., and R. Pincus (2012), DART/CAM: An Ensemble Data Assimilation System for CESM Atmospheric Models, J. Climate, 25, 6304–6317, doi:


Kay, J. E., Holland, M. M., and A. Jahn (2011), Inter-annual to multi-decadal Arctic sea ice extent trends in a warming world, Geophys. Res. Lett., 38, L15708, doi:10.1029/2011GL048008 NSF press release, favorite media coverage including the quote "The Arctic's summer ice coverage could hold its ground or even bounce back slightly, even as global average temperatures rise. But like a Guns 'n' Roses tour, the comeback will be short lived and eventually doomed to disappear."

Kay, J. E., Raeder, K., Gettelman, A. and J. Anderson (2011), The boundary layer response to recent Arctic sea ice loss and implications for high-latitude climate feedbacks, J. Climate, 24, 428-447, doi:10.1175/2010JCLI3651.1

Hwang, Y-T., Frierson, D. W., and J. E. Kay (2011), Coupling between Arctic feedbacks and changes in poleward energy transport, Geophys. Res. Lett.,38,L17704, doi:10.1029/2011GL048546

Medeiros, B., Deser, C. ,Tomas, R. A. and J. E. Kay (2011), Arctic inversion strength in climate models, J. Climate, 24, 4733-4740, doi: 10.1175/2011JCLI3968.1


Kay, J. E. and A. Gettelman (2009), Cloud influence on and response to seasonal Arctic sea ice loss, J. Geophys. Res., 114, D18204, doi:10.1029/2009JD011773

Gettelman, A., P. H. Lauritzen, M. Park, and J. E. Kay (2009), Processes regulating short-lived species in the tropical tropopause layer, J. Geophys. Res., 114, D13303, doi:10.1029/2009JD011785


Kay, J. E., L'Ecuyer, T., Gettelman, A., Stephens, G., and C. O'Dell (2008), The contribution of cloud and radiation anomalies to the 2007 Arctic sea ice extent minimum, Geophys. Res. Lett., 35, L08503, doi:10.1029/2008GL033451

Kay, J. E., and R. Wood (2008), Timescale analysis of aerosol sensitivity during homogeneous freezing and implications for upper tropospheric water vapor budgets, Geophys. Res. Lett., 35, L10809, doi:10.1029/2007GL032628


Kay, J. E., Baker, M., and D. Hegg (2007), Physical controls on orographic cirrus inhomogeneity. Atmos. Chem. Phys., 7, 3771-3781, doi:10.5194/acp-7-3771-2007.

Kay, J. E., Baker, M., and D. Hegg (2006), Microphysical and dynamical controls on cirrus cloud optical depth distributions, J. Geophys. Res.,111,D24205, doi:10.1029/2005JD006916

Kay, J. E., Tsemekhman, V., Larsen, B., Baker, M. and B. Swanson (2003), Comment on evidence for surface initiated homogeneous nucleation, Atmos. Phys. Chem., 3, 1439-1443, doi:10.5194/acp-3-1439-2003

Kay, J. E., Gillespie, A. R., Hansen, G. B., and E. Pettit (2003), Spatial relationships between snow contaminant content, grain size, and surface temperature from multispectral images of Mt. Rainier, Washington (USA), Remote Sensing of Environment, 86:2, 216-231.

Cherkauer, K.A., Burges, S.J. , Handcock, R.N., Kay, J. E., Kampf, S.K. and A.R. Gillespie (2005), Assessing satellite-based thermal-infrared remote-sensing for monitoring Pacific Northwest river temperatures, Journal of the American Water Resources Association, 41 (5), 1149-1160.

Handcock, R.N., Gillespie, A. R., Cherkauer, K. A., Kay, J. E., S. J. Burges, and S. K. Kampf (2005), Assessing satellite-based thermal-infrared remote-sensing for monitoring Pacific Northwest river temperatures, Journal of the American Water Resources Association, 41 (5), 1149-1160.

Simonelli, D. P., Kay, J., Adinolfi, D., Veverka, J., Thomas, P. C., and P. Helfenstein (1999), Phoebe: Albedo map and photometric properties, Icarus, 138, 249-258.

The University of Colorado Boulder is a world leader in polar research. Boulder has multiple climate research centers and amazing collaboration opportunities. Working where the Plains meet the Rockies provides a lot of inspiration. We hope you will consider joining us! Below are current opportunities to join our group. We especially welcome scientists with their own research funding. As always, contact us if you have questions or ideas for collaboration.

For prospective undergraduate students: We would be delighted to have you contribute to our group's research. You should have a strong background in computing/math/science.  One option is to write a joint research proposal for the University of Colorado's UROP program.

For prospective graduate students: Please apply to graduate school in ATOC and also consider applying for a fellowship: NSF Graduate Research Fellowship Program, NASA Earth and Space Science Fellowship.  The Kay group currently has openings for two Ph.D. students.

For prospective postdoctoral research fellows: Demonstrating your ability to pursue and fund independent research is especially important. Please let us know if you have an idea for a joint research proposal. In addition, the following fellowships are highly recommended: CIRES Fellowship, NOAA Climate and Global Change Fellowship, NSF Atmospheric and Geospace Sciences Fellowship

  • ATOC 5600 - Physics and Chemistry of Clouds and Aerosols (Spring 2014, Spring 2016)
  • ATOC 1060 - Our Changing Environment (Fall 2014, Fall 2015, Spring 2017, Fall 2017)
  • ATOC 4500/7500 - Climate Modeling (Fall 2016)
  • ATOC 6020 - Polar Discussion Seminar (Every Fall, Fall 2016 focused on sea ice)

The Kay Group does Education and Outreach with Polar Bears International.  During Fall 2014 - Jen taught an ATOC1060 lecture on polar bears, sea ice, and climate change from Churchill, Manitoba - the polar bear capital of the world.  You can watch the lecture on utube here: ATOC1060 from the tundra!  




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