Name OceanFlux Upwelling
Title ESA-SOLAS OceanFlux Upwelling
Thematic Area Ocean
Cost 100 - 200 K
Action Line International Scientific Cooperation
Status Completed in 2015
Missions ENVISAT, GOSAT, METOP
Sensors MERIS, AATSR, SCIAMACHY, ASCAT, TANSO
Objectives OceanFlux aims at reinforcing the scientific collaboration with the Surface Ocean-Lower Atmosphere Study (SOLAS), an international research initiative meant to achieve quantitative understanding of the key biogeochemical-physical interactions and feedbacks between the ocean and atmosphere. Within this context, OceanFlux Upwelling aims at exploring the potential of EO technology to characterise the role of ocean upwelling processes as sinks and/or sources of greenhouse gases (GHG), with a distinctive focus on the Eastern Boundary Upwelling Systems (EBUS). The EBUS and the associated OMZs (Oxygen Minimum Zones) contribute very significantly to the gas exchange between the ocean and the atmosphere, notably with respect to GHG. However, from in-situ measurements it is estimated that the uncertainty of the global net ocean-atmosphere CO2 fluxes is between 20% and 30%, and could be much higher in the EBUS-OMZ. In this framework, the overarching scientific questions to be answered by OceanFlux Upwelling are: Which is the spatio-temporal variability of the net GHG effect in the EBUS? Are the uptake/release of the most important long-lived radiatively-active gases coupled or decoupled with these upwelling events? To address these questions, state-of-the art modeling techniques applied to Vertical Column Densities (VCDs) of SCIAMACHY and GOSAT were used together with image processing techniques for improving the signal-to-noise ratio and extracting fluxes of GHGs (CO2, currently) from EO data at low spatial resolution. Since current data from the SCIMACHY and GOSAT instrument turned out to be of not enough quality and too sparse, respectively, simulated column densities of GHGs with real noise characteristics (from the Carbontracker project) have also been used as low resolution input. Through concomitant information on gas solubility (dependent on SST and salinity) and parameterizations of gas transfer velocities (mainly related to wind speed), it has been possible to extract the partial pressure of CO2 in the ocean. Nevertheless, for accurately linking sources of GHGs to EBUS and OMZs, the spatial resolution of the source regions needs to be increased. This task capitalizes on new non-linear and multi-scale processing methods for complex signals to infer a higher spatial resolution mapping of the fluxes and the associated sinks/sources. The use of coupled satellite data (e.g. SST and/or Ocean Color) that carry turbulence information associated to ocean dynamics is taken into account at unprecedented level of detail to incorporate turbulence effects in the evaluation of the air-sea fluxes. These analyses have been linked to a fully-validated coupled physical bio-geochemical model (ROMS-BioBus), and a comparison of results have been carried out with a wide range of in-situ and simulated data over the two main areas of interest: the Peru-Chile and Benguela upwelling systems. The current project extension is allowing a further refinement of the super-resolution CO2 ocean fluxes more comprehensive validation of the methodology, enlarging the two test areas beyond the initial upwelling zones. Besides CO2 fluxes, it is foreseen to tentatively derive also the sink/source configuration of the DMS (dimethylsulphide) using EO derived phytoplankton functional types.
Project Partners U Heidelberg : Ruprecht-Karls-Universität Heidelberg(Prime contractor)CNRS-LEGOS : Centre National de la Recherche Scientifique - LEGOS(Subcontractor)KIT : Karlsruhe Instìtute of Technology(Subcontractor)
Project Manager Dr. Christoph S. Garbe Interdisciplinary Center for Scientific Computing (IWR) University of Heidelberg Speyerer Str. 6 D-€69115, Heidelberg, Germany Tel: +49 (6221) 548876 Fax: +49 (6221) 548790 email: Christoph.Garbe@iwr.uni-heidelberg.de
Technical Officer Roberto Sabia