Observation system simulation experiments in the Atlantic Ocean for enhanced surface ocean p CO 2 reconstructions

• Published in: Ocean Science
• Main Authors: Denvil-Sommer, Anna, Gehlen, Marion, Vrac, Mathieu
• Other Authors: School of Environmental Sciences Norwich, University of East Anglia Norwich (UEA), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), This research has been supported by GreenGrog (GMMC).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Southern Ocean
• Online Access: https://hal.science/hal-03317906; https://hal.science/hal-03317906/document; https://hal.science/hal-03317906/file/os-17-1011-2021.pdf; https://doi.org/10.5194/os-17-1011-2021

International audience To derive an optimal observation system for surface ocean pCO 2 in the Atlantic Ocean and the Atlantic sector of the Southern Ocean, 11 observation system simulation experiments (OSSEs) were completed. Each OSSE is a feedforward neural network (FFNN) that is based on a different data distribution and provides ocean surface pCO 2 for the period 2008-2010 with a 5 d time interval. Based on the geographical and time positions from three observational platforms, volunteering observing ships, Argo floats and OceanSITES moorings, pseudo-observations were constructed using the outputs from an online-coupled physicalbiogeochemical global ocean model with 0.25 • nominal resolution. The aim of this work was to find an optimal spatial distribution of observations to supplement the widely used Surface Ocean CO 2 Atlas (SOCAT) and to improve the accuracy of ocean surface pCO 2 reconstructions. OSSEs showed that the additional data from mooring stations and an improved coverage of the Southern Hemisphere with biogeochemical ARGO floats corresponding to least 25 % of the density of active floats (2008-2010) (OSSE 10) would significantly improve the pCO 2 reconstruction and reduce the bias of derived estimates of sea-air CO 2 fluxes by 74 % compared to ocean model outputs.