Evaluation of ocean dimethylsulfide concentration and emission in CMIP6 models

Abstract. Characteristics and trends of surface ocean dimethylsulfide (DMS) concentrations fluxes into the atmosphere four Earth system models (ESMs: CNRM-ESM2-1, MIROC-ES2L, NorESM2-LM, UKESM1-0-LL) are analysed over recent past (1980–2009) future, using Coupled Model Intercomparison Project 6 (CMIP6) simulations. The DMS in historical simulations systematically underestimate most widely used observed climatology but compare more favourably against two observation-based datasets. better reproduce observations mid to high latitudes, as well polar westerlies marine biomes. resulting multi-model estimate contemporary global emissions is 16–24 Tg S yr−1, which narrower than observational-derived range 16 28 yr−1. disagree on sign trend flux from 1980 onwards, with showing an increase a decrease. At scale, these dominated by changes all models, irrespective air–sea parameterisation used. In turn, three consistently show that correlated productivity; however, productivity poorly constrained current generation ESMs, thus limiting predictive ability this relationship. contrast, consensus found among latitudes where increasing predominantly driven retreating sea-ice extent. However, magnitude between differs factor 3, 2.9 9.2 Gg decade−1 period 1980–2014, at low end satellite-derived analysis. Similar climate projections 21st century.