FN Archimer Export Format
PT J
TI Coupling of a sediment diagenesis model (MEDUSA) and an Earth system model (CESM1.2): a contribution toward enhanced marine biogeochemical modelling and long-term climate simulations
BT 
AF KURAHASHI-NAKAMURA, Takasumi
   PAUL, Andre
   MUNHOVEN, Guy
   MERKEL, Ute
   SCHULZ, Michael
AS 1:1,2;2:1,2;3:3;4:1,2;5:1,2;
FF 1:;2:;3:;4:;5:;
C1 Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen, Germany.
   Univ Bremen, Fac Geosci, Bremen, Germany.
   Univ Liege, Lab Phys Atmospher & Planetaire, Liege, Belgium.
C2 UNIV BREMEN MARUM, GERMANY
   UNIV BREMEN, GERMANY
   UNIV LIEGE, BELGIUM
IN DOAJ
IF 1.591
TC 5
UR https://archimer.ifremer.fr/doc/00676/78790/81068.pdf
   https://archimer.ifremer.fr/doc/00676/78790/81069.pdf
   https://archimer.ifremer.fr/doc/00676/78790/81070.pdf
LA English
DT Article
CR OISO - OCÉAN INDIEN SERVICE D'OBSERVATION
AB We developed a coupling scheme for the Community Earth System Model version 1.2 (CESM1.2) and the Model of Early Diagenesis in the Upper Sediment of Adjustable complexity (MEDUSA), and explored the effects of the coupling on solid components in the upper sediment and on bottom seawater chemistry by comparing the coupled model's behaviour with that of the uncoupled CESM having a simplified treatment of sediment processes. CESM is a fully coupled atmosphere-ocean-sea-ice-land model and its ocean component (the Parallel Ocean Program version 2; POP2) includes a biogeochemical component (the Biogeochemical Elemental Cycling model; BEC). MEDUSA was coupled to POP2 in an offline manner so that each of the models ran separately and sequentially with regular exchanges of necessary boundary condition fields. This development was done with the ambitious aim of a future application for long-term (spanning a full glacial cycle; i.e. similar to 10(5) years) climate simulations with a state-of-the-art comprehensive climate model including the carbon cycle, and was motivated by the fact that until now such simulations have been done only with less-complex climate models. We found that the sediment-model coupling already had non-negligible immediate advantages for ocean biogeochemistry in millennial-timescale simulations. First, the MEDUSA-coupled CESM outperformed the uncoupled CESM in reproducing an observation-based global distribution of sediment properties, especially for organic carbon and opal. Thus, the coupled model is expected to act as a better "bridge" between climate dynamics and sedimentary data, which will provide another measure of model performance. Second, in our experiments, the MEDUSA-coupled model and the uncoupled model had a difference of 0.2 parts per thousand or larger in terms of delta C-13 of bottom water over large areas, which implied a potentially significant model uncertainty for bottom seawater chemical composition due to a different way of sediment treatment. For example, an ocean model that does not treat sedimentary processes depending on the chemical composition of the ambient water can overestimate the amount of remineralization of organic matter in the upper sediment in an anoxic environment, which would lead to lighter delta C-13 values in the bottom water. Such a model uncertainty would be a fundamental issue for paleo model-data comparison often relying on data derived from benthic foraminifera. 
PY 2020
PD MAR
SO Geoscientific Model Development
SN 1991-959X
PU Copernicus Gesellschaft Mbh
VL 13
IS 2
UT 000518769300002
BP 825
EP 840
DI 10.5194/gmd-13-825-2020
ID 78790
ER

EF