A Global Sea Surface Carbon Observing System: Assessment of Changing Sea Surface CO2 and Air-Sea CO2 Fluxes

Abstract

SUMMARYThis paper identifies the important advances of the past decade that have delivered high precision pCO 2 observations from ships of opportunity (SOOP), robust decadal climatologies of air-sea CO 2 fluxes, and uniform data through coordinated quality control and inter comparisons activities, along with standardized instrumentation and procedures. The vision for the coming decade is to build on these successes to deliver an annual assessment and understanding of the regional and global trends in CO 2 exchanges between the ocean and the atmosphere. The core challenges are the maintenance and expansion of the sampling scales and the development of robust high precision in situ sensors.Highest priorities for the next 10 years for a global sea surface carbon observing system are: to deliver seasonally unbiased annual assessments of the regional and global trends in oceanatmosphere carbon fluxes. These should comprise monthly global flux maps that are used as constraints for atmospheric inversions in order to improve the assessment of the global carbon budget, including the terrestrial component. This will form an important link between the ocean CO 2 community and the global carbon budget assessment activities of the Global Carbon project (GCP) and its inputs to the periodic IPCC assessments. In order to achieve this, the following are necessary: to implement an effective and integrated multiplatform pCO 2 observing network that will reduce uncertainty in regional and global CO 2 flux estimates to ± 10 -15% of the annual mean flux; to advance sensor and instrument development, allowing the density of global surface ocean carbon observing networks to be increased by deployment on additional key SOOP lines, moorings, Lagrangian platforms, gliders and profiling floats. to understand and resolve the biogeochemical and physical mechanisms driving surface carbon, natural and anthropogenic CO 2 air-sea flux variability and long term trend sand a link to ocean acidification by incorporating a robust set of ancillary observations; to strengthen the capabilities of coupled climatecarbon models to forecast changes in the ocean uptake of CO 2 and the effectiveness of CO 2 emission mitigation strategies

Impact of episodic vertical fluxes on sea surface pCO 2

“…Regions and times that show a large sensitivity of surface pCO 2 to vertical mixing can be expected to exhibit greater spatial and temporal variance in surface pCO 2 , which has consequences for calculating carbon budgets [41]. Secondly, changes in pCO 2 are concomitant with a change in seawater pH, or ocean acidification.…”

The Way Forward in Developing and Integrating Ferrybox Technologies

“…For example, sensor systems are needed to measure CO 2 related parameters to study the relationship between anthropogenic CO 2 release and ocean uptake, and consequent ocean acidification (Borges et al; Feeley et al and Monteiro et al, 2010). Instruments to determine pCO 2 are available.…”

Sensors and Systems for In Situ Observations of Marine Carbon Dioxide System Variables

“…Documentation of the marine carbon dioxide system's evolving response to anthropogenic CO2 inputs, as well as impacts on short-and long-term carbon cycling, will require sustained systematic and strategic measurement programs [1,2] that include the use of autonomous chemical sensors. Knowledge of two CO2 system parameters, including CO2 fugacity 1 (fCO2), total alkalinity (AT), total dissolved inorganic carbon (DIC), pH, and carbonate ion (CO3 2-) concentration, is sufficient for calculation of all system parameters.…”