Dimethylsulphide production in the subantarctic southern ocean under enhanced greenhouse conditions

Citation
Aj. Gabric et al., Dimethylsulphide production in the subantarctic southern ocean under enhanced greenhouse conditions, TELLUS B, 53(3), 2001, pp. 273-287
Citations number
76
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY
ISSN journal
0280-6509 → ACNP
Volume
53
Issue
3
Year of publication
2001
Pages
273 - 287
Database
ISI
SICI code
0280-6509(200106)53:3<273:DPITSS>2.0.ZU;2-E
Abstract
Dimethylsulphide (DMS) is an important sulphur-containing trace gas produce d by enzymatic cleavage of its precursor compound. dimethylsulphoniopropion ate (DMSP), which is released by marine phytoplanklon in the upper ocean. A fter ventilation to the atmosphere, DMS is oxidised to form sulphate aeroso ls which in the unpolluted marine atmosphere are a major source of cloud co ndensation nuclei (CCN). Because the micro-physical properties of clouds re levant to climate change are sensitive to CCN concentration in air; it has been postulated that marine sulphur emissions may play a role in climate re gulation. The Subantarctic Southern Ocean (41-53 degreesC) is relatively fr ee of anthropogenic sulphur emissions. thus sulphate aerosols will be mainl y derived from the biogenic source of DMS, making it an ideal region in whi ch to evaluate the DMS-climate regulation hypothesis. We have extended a pr evious modelling analysis of the DMS cycle in this region by employing a co upled general circulation model (CGCM) which has been run in transient mode to provide a more realistic climate scenario. The CGCM output provided met eorological data under the IPCC/IS92a radiative forcing scenario. A DMS pro duction model has been forced with the CGCM climate data to simulate the tr end in the sea-to-air DMS flux for the period 1960 to 2080, corresponding t o equivalent CO, tripling relative to pre-industrial levels. The results co nfirm a minor but non-negligible increase in DMS flux in this region. in th e range +1% to +6% predicted over the period simulated. Uncertainty analysi s of the DMS model predictions have confirmed the positive sign for the cha nge in DMS Aux, that is a negative DMS feedback on warming.