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Title: The tropical rain belts with an annual cycle and a continent model intercomparison project: TRACMIP

This paper introduces the Tropical Rain belts with an Annual cycle and a Continent Model Intercomparison Project (TRACMIP). TRACMIP studies the dynamics of tropical rain belts and their response to past and future radiative forcings through simulations with 13 comprehensive and one simplified atmosphere models coupled to a slab ocean and driven by seasonally-varying insolation. Five idealized experiments, two with an aquaplanet setup and three with a setup with an idealized tropical continent, fill the space between prescribed-SST aquaplanet simulations and realistic simulations provided by CMIP5/6. The simulations reproduce key features of the present-day climate and expected future climate change, including an annual-mean intertropical convergence zone (ITCZ) that is located north of the equator and Hadley cells and eddy-driven jets that are similar to the present-day climate. Quadrupling CO 2 leads to a northward ITCZ shift and preferential warming in Northern high-latitudes. The simulations show interesting CO 2-induced changes in the seasonal excursion of the ITCZ and indicate a possible state-dependence of climate sensitivity. The inclusion of an idealized continent modulates both the control climate and the response to increased CO 2; for example it reduces the northward ITCZ shift associated with warming and, in some models, climate sensitivity. Inmore » response to eccentricity-driven seasonal insolation changes, seasonal changes in oceanic rainfall are best characterized as a meridional dipole, while seasonal continental rainfall changes tend to be symmetric about the equator. Finally, this survey illustrates TRACMIP’s potential to engender a deeper understanding of global and regional climate phenomena and to address pressing questions on past and future climate change.« less
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  1. Karlsruhe Institute of Technology, Karlsruhe (Germany); Columbia Univ., New York, NY (United States)
  2. Columbia Univ., New York, NY (United States)
  3. Max Planck Institute for Meteorology, Hamburg (Germany)
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  5. Sorbonne Univ., Paris (France)
  6. Univ. of Wisconsin, Madison, WI (United States)
  7. Ulsan National Institute of Science and Technology, Ulsan (South Korea)
  8. Univ. of Reading, Reading (United Kingdom)
  9. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  10. Univ. of Miami, Miami, FL (United States)
  11. Univ. of Washington, Seattle, WA (United States)
  12. New York Univ., New York, NY (United States)
  13. Centre National de Recherches Meteorologiques, Toulouse (France)
  14. Univ. at Albany (State Univ. of New York), Albany, NY (United States)
  15. NASA Goddard Institute for Space Studies, New York, NY (United States)
  16. Bjerknes Centre for Climate Research, Bergen (Norway)
  17. Hokkaido Univ., Sapporo (Japan)
Publication Date:
Report Number(s):
Journal ID: ISSN 1942-2466; KP1703010
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Advances in Modeling Earth Systems
Additional Journal Information:
Journal Volume: 8; Journal Issue: 4; Journal ID: ISSN 1942-2466
American Geophysical Union (AGU)
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
Country of Publication:
United States
OSTI Identifier: