Modellierung der globalen biogeochemischen Stoffverteilung im glazialen Ozean: Ein Modell-Datenvergleich
|Other Titles:||Modellling the global biogeochemical tracer distribution in the glacial ocean: A model-data comparison||Authors:||Matthies, Michael||Supervisor:||Herterich, Klaus||1. Expert:||Herterich, Klaus||2. Expert:||Ittekkot, Venugopalan||Abstract:||
:br:In this work, a numeric three-dimensional biogeochemical model of the global carbon-cycle (HAMOCC2) was coupled to an ocean general circulation model (LSG) to explore the :img:=delta.gif:/img::sup:13:/sup:C distribution in the glacial Atlantic. In addition to the model comparison of the present-day (pre-industrial) distribution of the components of the marine carbon system with observations (GEOSECS), three model experiments for the Last Glacial Maximum (LGM) were carried out. For the present-day ocean, adequate correlations between model and observations were obtained. However, deviations occurred in the isotopes pattern of :img:=delta1.gif:/img::sup:14:/sup:C and :img:=delta.gif:/img::sup:13:/sup:C, which are primary due to problems of modelling the North Atlantic Deep Water (NADW). On the other side, uncertainties in the observed :img:=delta.gif:/img::sup:13:/sup:C values should be also taken into account. The simulated glacial :img:=delta.gif:/img::sup:13:/sup:C pattern was compared with a new data set of benthic carbon isotopes of the Western and Eastern Atlantic from the Last Glacial Maximum (21,000 -- 23,500 calendar years before present). The model output fits the :img:=delta.gif:/img::sup:13:/sup:C distribution derived from sediment samples, when the glacial export of NADW to the Southern Ocean was reduced by 50 % and the inflow of glacial Antarctic Bottom Water (AABW) was held constant. Usually, the modeled :img:=delta.gif:/img::sup:13:/sup:C pattern matched the paleodata within a range of ±0.2 per mil. No additional increase of the nutrient inventory of the deep ocean was necessary to reproduce the paleodata. Hence it is concluded that a significant increase in biological pumping during glacials may not be necessary to explain the reconstructed :img:=delta.gif:/img::sup:13:/sup:C distribution in this region. The results are discussed with respect to other scenarios for the decrease of global atmospheric carbon dioxide.
|Keywords:||LGM, mariner Kohlenstoffkreislauf, Kohlenstoffisotope, Biologische Pumpe, Karbonat-Pumpe, Lysokline, carbon isotope, marine carbon cycle, model||Issue Date:||3-Jun-2003||URN:||urn:nbn:de:gbv:46-diss000006067||Institution:||Universität Bremen||Faculty:||FB5 Geowissenschaften|
|Appears in Collections:||Dissertationen|
checked on Sep 20, 2020
checked on Sep 20, 2020
Items in Media are protected by copyright, with all rights reserved, unless otherwise indicated.