Evaluation of global ocean-sea-ice model simulations based on the experimental protocols of the Ocean Model Intercomparison Project phase 2 (OMIP-2)

• Published in: Geoscientific Model Development
• Other Authors: Tsujino, Hiroyuki (author), Urakawa, L. Shogo (author), Griffies, Stephen M. (author), Danabasoglu, Gokhan (author), Adcroft, Alistair J. (author), Amaral, Arthur E. (author), Arsouze, Thomas (author), Bentsen, Mats (author), Bernardello, Raffaele (author), Böning, Claus W. (author), Bozec, Alexandra (author), Chassignet, Eric P. (author), Danilov, Sergey (author), Dussin, Raphael (author), Exarchou, Eleftheria (author), Fogli, Pier Giuseppe (author), Fox-Kemper, Baylor (author), Guo, Chuncheng (author), Ilicak, Mehmet (author), Iovino, Doroteaciro (author), Kim, Who M. (author), Koldunov, Nikolay (author), Lapin, Vladimir (author), Li, Yiwen (author), Lin, Pengfei (author), Lindsay, Keith (author), Liu, Hailong (author), Long, Matthew C. (author), Komuro, Yoshiki (author), Marsland, Simon J. (author), Masina, Simona (author), Nummelin, Aleksi (author), Rieck, Jan Klaus (author), Ruprich-Robert, Yohan (author), Scheinert, Markus (author), Sicardi, Valentina (author), Sidorenko, Dmitry (author), Suzuki, Tatsuo (author), Tatebe, Hiroaki (author), Wang, Qiang (author), Yeager, Stephen G. (author), Yu, Zipeng (author)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Sea ice
• Online Access: https://doi.org/10.5194/gmd-13-3643-2020

We present a new framework for global oceansea-ice model simulations based on phase 2 of the Ocean Model Intercomparison Project (OMIP-2), making use of the surface dataset based on the Japanese 55-year atmospheric reanalysis for driving ocean-sea-ice models (JRA55-do). We motivate the use of OMIP-2 over the framework for the first phase of OMIP (OMIP-1), previously referred to as the Coordinated Ocean-ice Reference Experiments (COREs), via the evaluation of OMIP-1 and OMIP-2 simulations from 11 state-of-the-science global ocean-sea-ice models. In the present evaluation, multi-model ensemble means and spreads are calculated separately for the OMIP-1 and OMIP-2 simulations and overall performance is assessed considering metrics commonly used by ocean modelers. Both OMIP-1 and OMIP-2 multi-model ensemble ranges capture observations in more than 80 % of the time and region for most metrics, with the multi-model ensemble spread greatly exceeding the difference between the means of the two datasets. Many features, including some climatologically relevant ocean circulation indices, are very similar between OMIP-1 and OMIP-2 simulations, and yet we could also identify key qualitative improvements in transitioning from OMIP-1 to OMIP-2. For example, the sea surface temperatures of the OMIP-2 simulations reproduce the observed global warming during the 1980s and 1990s, as well as the warming slowdown in the 2000s and the more recent accelerated warming, which were absent in OMIP-1, noting that the last feature is part of the design of OMIP-2 because OMIP-1 forcing stopped in 2009. A negative bias in the sea-ice concentration in summer of both hemispheres in OMIP-1 is significantly reduced in OMIP-2. The overall reproducibility of both seasonal and interannual variations in sea surface temperature and sea surface height (dynamic sea level) is improved in OMIP-2. These improvements represent a new capability of the OMIP-2 framework for evaluating processlevel responses using simulation results. Regarding the sensitivity of ...