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LongRunMIP – motivation and design for a large collection of millennial-length AO-GCM simulations

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Rugenstein Maria, Bloch-Johnson Jonah, Abe-Ouchi Ayako, Andrews Timothy, Beyerle Urs, Cao Long, Chadha Tarun, Danabasoglu Gokhan, Dufresne Jean-Louis, Duan Lei, Foujols Marie-Alice, Frölicher Thomas, Geoffroy Olivier, Gregory Jonathan, Knutti Reto, Li Chao, Marzocchi Alice, Mauritsen Thorsten, Moyer Elisabeth, Nazarenko Larissa, Paynter David, Saint-Martin David, Schmidt Gavin A., Yamamoto Akitomo, Yang Shuting,
Project Ocean extremes in a warmer world: Discovering risks for marine ecosystems (OceanX)
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Original article (peer-reviewed)

Journal Bull. Amer. Meteor. Soc.
Publisher American Meteorological Society, Bull. Amer. Meteor. Soc.
Title of proceedings Bull. Amer. Meteor. Soc.
DOI 10.1175/bams-d-19-0068.1

Open Access

Type of Open Access Publisher (Gold Open Access)


LongRunMIP is the first collection of millennial-length simulations of complex coupled climate models and enables investigations of how these models equilibrate in response to radiative perturbations. We present a model intercomparison project, LongRunMIP, the first collection of millennial-length (1000+ year) simulations of complex coupled climate models with a representation of ocean, atmosphere, sea ice, and land surface, and their interactions. Standard model simulations are generally only a few hundred years long. However, modeling the long-term equilibration in response to radiative forcing perturbation is important for understanding many climate phenomena, such as the evolution of ocean circulation, time-and temperature-dependent feedbacks, and the differentiation of forced signal and internal variability. The aim of LongRunMIP is to facilitate research into these questions by serving as an archive for simulations that capture as much of this equilibration as possible. The only requirement to participate in LongRunMIP is to contribute a simulation with elevated, constant CO2 forcing that lasts at least 1000 years. LongRunMIP is a MIP of opportunity in that the simulations were mostly performed prior to the conception of the archive without an agreed-upon set of experiments. For most models, the archive contains a preindustrial control simulation and simulations with an idealized (typically abrupt) CO2 forcing. We collect 2D surface and top-of-atmosphere fields, and 3D ocean temperature and salinity fields. Here, we document the collection of simulations and discuss initial results, including the evolution of surface and deep ocean temperature and cloud radiative effects. As of summer 2019, the collection includes 50 simulations of 15 models by 10 modeling centers. The data of LongRunMIP are publicly available. We encourage submission of more simulations in the future.