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Modeling estimates of the global emission of dimethylsulfide under enhanced greenhouse conditions
Author(s) -
Gabric A. J.,
Simó R.,
Cropp R. A.,
Hirst A. C.,
Dachs J.
Publication year - 2004
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2003gb002183
Subject(s) - environmental science , climatology , mixed layer , atmospheric sciences , latitude , northern hemisphere , gcm transcription factors , climate model , climate change , southern hemisphere , perturbation (astronomy) , general circulation model , oceanography , geology , physics , geodesy , quantum mechanics
We have used a marine food‐web model, an atmosphere‐ocean general circulation model (GCM), and an empirical dimethylsulfide (DMS) algorithm to predict the DMS seawater concentration and the DMS sea‐to‐air flux in 10° latitude bands from 70°N to 70°S under contemporary and enhanced greenhouse conditions. The DMS empirical algorithm utilizes the food‐web model predictions of surface chlorophyll and the GCM's simulation of oceanic mixed layer depth. The food‐web model was first calibrated to contemporary climate conditions using satellite‐derived chlorophyll data and meteorological forcings. For the climate change simulations, the meteorological forcings were derived from a transient simulation of the CSIRO Mark 2 GCM, using the IPCC/IS92a radiative forcing scenario to the period of equivalent CO 2 tripling (2080). The globally integrated DMS flux perturbation is predicted to be +14%; however, we found strong latitudinal variation in the perturbation. The greatest perturbation to DMS flux is simulated at high latitudes in both hemispheres, with little change predicted in the tropics and sub‐tropics. The largest change in annual integrated flux (+106%) is simulated in the Southern Hemisphere between 50°S and 60°S. At this latitude, the DMS flux perturbation is most influenced by the GCM‐simulated changes in the mixed layer depth. The results indicate that future increases in stratification in the polar oceans will play a critical role in the DMS cycle and climate change.