Tim Carlsen

• Pasquier, Julie T.; Henneberger, Jan; Korolev, Alexei; Ramelli, Fabiola; Wieder, Jörg & Lauber, Annika [Vis alle 12 forfattere av denne artikkelen] (2023). Understanding the History of Two Complex Ice Crystal Habits Deduced From a Holographic Imager. Geophysical Research Letters. ISSN 0094-8276. 50(1). doi: 10.1029/2022GL100247. Fulltekst i vitenarkiv
• Pasquier, Julie Thérèse; Henneberger, Jan; Ramelli, Fabiola; Lauber, Annika; David, Robert Oscar & Wieder, Jörg [Vis alle 10 forfattere av denne artikkelen] (2022). Conditions favorable for secondary ice production in Arctic mixed-phase clouds. Atmospheric Chemistry and Physics (ACP). ISSN 1680-7316. 22(23), s. 15579–15601. doi: 10.5194/acp-22-15579-2022. Fulltekst i vitenarkiv
• Pasquier, Julie T.; David, Robert Oscar; Freitas, Gabriel; Gierens, Rosa; Gramlich, Yvette & Haslett, Sophie [Vis alle 44 forfattere av denne artikkelen] (2022). The Ny-Ålesund Aerosol Cloud Experiment (NASCENT) Overview and First Results. Bulletin of The American Meteorological Society - (BAMS). ISSN 0003-0007. 103(11), s. E2533–E2558. doi: 10.1175/BAMS-D-21-0034.1. Fulltekst i vitenarkiv
• Schäfer, Britta; Carlsen, Tim; Hanssen, Ingrid; Gausa, Michael & Storelvmo, Trude (2022). Observations of cold-cloud properties in the Norwegian Arctic using ground-based and spaceborne lidar. Atmospheric Chemistry and Physics (ACP). ISSN 1680-7316. 22(14), s. 9537–9551. doi: 10.5194/acp-22-9537-2022. Fulltekst i vitenarkiv
• Carlsen, Tim & David, Robert Oscar (2022). Spaceborne Evidence That Ice-Nucleating Particles Influence High-Latitude Cloud Phase. Geophysical Research Letters. ISSN 0094-8276. 49(14). doi: 10.1029/2022GL098041. Fulltekst i vitenarkiv
• Becker, Sebastian; Ehrlich, André; Jäkel, Evelyn; Carlsen, Tim; Schäfer, Michael & Wendisch, Manfred (2022). Airborne measurements of directional reflectivity over the Arctic marginal sea ice zone. Atmospheric Measurement Techniques. ISSN 1867-1381. 15(9), s. 2939–2953. doi: 10.5194/amt-15-2939-2022. Fulltekst i vitenarkiv
• Engdahl, Bjørg Jenny Kokkvoll; Carlsen, Tim; Køltzow, Morten Andreas Ødegaard & Storelvmo, Trude (2022). The Ability of the ICE-T Microphysics Scheme in HARMONIE-AROME to Predict Aircraft Icing. Weather and forecasting. ISSN 0882-8156. 37(2), s. 205–217. doi: 10.1175/WAF-D-21-0104.1. Fulltekst i vitenarkiv
• Hofer, Stefan; Amory, Charles; Kittel, Christoph; Carlsen, Tim; Le Toumelin, Louis & Storelvmo, Trude (2021). The Contribution of Drifting Snow to Cloud Properties and the Atmospheric Radiative Budget Over Antarctica. Geophysical Research Letters. ISSN 0094-8276. 48(22). doi: 10.1029/2021GL094967. Fulltekst i vitenarkiv
• Jäkel, Evelyn; Carlsen, Tim; Ehrlich, André; Wendisch, Manfred; Schäfer, Michael & Rosenburg, Sophie [Vis alle 14 forfattere av denne artikkelen] (2021). Measurements and Modeling of Optical-Equivalent Snow Grain Sizes under Arctic Low-Sun Conditions. Remote Sensing. ISSN 2072-4292. 13(23). doi: 10.3390/rs13234904. Fulltekst i vitenarkiv
• Carlsen, Tim; Birnbaum, G.; Ehrlich, André; Helm, Veit; Jäkel, Evelyn & Schäfer, Michael [Vis alle 7 forfattere av denne artikkelen] (2020). Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica. The Cryosphere. ISSN 1994-0416. 14(11), s. 3959–3978. doi: 10.5194/tc-14-3959-2020.
• Bjordal, Jenny; Storelvmo, Trude; Alterskjær, Kari & Carlsen, Tim (2020). Equilibrium climate sensitivity above 5 °C plausible due to state-dependent cloud feedback. Nature Geoscience. ISSN 1752-0894. 13, s. 718–721. doi: 10.1038/s41561-020-00649-1. Fulltekst i vitenarkiv Vis sammendrag

  The equilibrium climate sensitivity of Earth is defined as the global mean surface air temperature increase that follows a doubling of atmospheric carbon dioxide. For decades, global climate models have predicted it as between approximately 2 and 4.5 °C. However, a large subset of models participating in the 6th Coupled Model Intercomparison Project predict values exceeding 5 °C. The difference has been attributed to the radiative effects of clouds, which are better captured in these models, but the underlying physical mechanism and thus how realistic such high climate sensitivities are remain unclear. Here we analyse Community Earth System Model simulations and find that, as the climate warms, the progressive reduction of ice content in clouds relative to liquid leads to increased reflectivity and a negative feedback that restrains climate warming, in particular over the Southern Ocean. However, once the clouds are predominantly liquid, this negative feedback vanishes. Thereafter, other positive cloud feedback mechanisms dominate, leading to a transition to a high-sensitivity climate state. Although the exact timing and magnitude of the transition may be model dependent, our findings suggest that the state dependence of the cloud-phase feedbacks is a crucial factor in the evolution of Earth’s climate sensitivity with warming.

• Carlsen, Tim; Birnbaum, Gerit; Ehrlich, André; Freitag, Johannes; Heygster, Georg & Istomina, Larysa [Vis alle 10 forfattere av denne artikkelen] (2017). Comparison of different methods to retrieve optical-equivalent snow grain size in central Antarctica. The Cryosphere. ISSN 1994-0416. 11(6), s. 2727–2741. doi: 10.5194/tc-11-2727-2017.
• Werner, Martin; Langebroek, Petra; Carlsen, Tim; Herold, Marcus & Lohmann, Gerrit (2011). Stable water isotopes in the ECHAM5 general circulation model: Toward high-resolution isotope modeling on a global scale. Journal of Geophysical Research (JGR): Atmospheres. ISSN 2169-897X. 116(D15109). doi: 10.1029/2011JD015681.

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