scholarly journals Interannual sea–air CO<sub>2</sub> flux variability from an observation-driven ocean mixed-layer scheme

2014 ◽  
Vol 11 (17) ◽  
pp. 4599-4613 ◽  
Author(s):  
C. Rödenbeck ◽  
D. C. E. Bakker ◽  
N. Metzl ◽  
A. Olsen ◽  
C. Sabine ◽  
...  
Keyword(s):  
Southern Oscillation ◽  
Atmospheric Oxygen ◽  
Large Fraction ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Co2 Partial Pressure ◽  
Surface Ocean ◽  
The North ◽  
Ocean Carbon ◽  
Carbon Dioxide Co2

Abstract. Interannual anomalies in the sea–air carbon dioxide (CO2) exchange have been estimated from surface-ocean CO2 partial pressure measurements. Available data are sufficient to constrain these anomalies in large parts of the tropical and North Pacific and in the North Atlantic, in some areas covering the period from the mid 1980s to 2011. Global interannual variability is estimated as about 0.31 Pg C yr−1 (temporal standard deviation 1993–2008). The tropical Pacific accounts for a large fraction of this global variability, closely tied to El Niño–Southern Oscillation (ENSO). Anomalies occur more than 6 months later in the east than in the west. The estimated amplitude and ENSO response are roughly consistent with independent information from atmospheric oxygen data. This both supports the variability estimated from surface-ocean carbon data and demonstrates the potential of the atmospheric oxygen signal to constrain ocean biogeochemical processes. The ocean variability estimated from surface-ocean carbon data can be used to improve land CO2 flux estimates from atmospheric inversions.

scholarly journals Interannual sea–air CO<sub>2</sub> flux variability from an observation-driven ocean mixed-layer scheme

2014 ◽  
Vol 11 (2) ◽  
pp. 3167-3207 ◽  
Author(s):  
C. Rödenbeck ◽  
D. C. E. Bakker ◽  
N. Metzl ◽  
A. Olsen ◽  
C. Sabine ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Large Fraction ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Co2 Partial Pressure ◽  
Surface Ocean ◽  
Independent Information ◽  
Northern Pacific ◽  
Ocean Carbon ◽  
Carbon Dioxide Co2

Abstract. Interannual anomalies in the sea–air carbon dioxide (CO2) exchange have been estimated from surface-ocean CO2 partial pressure measurements. Available data are sufficient to constrain these anomalies in large parts of the tropical and Northern Pacific and in the Northern Atlantic, in some areas since the mid 1980s to 2011. Global interannual variability is estimated as about 0.31 Pg C yr−1 (temporal standard deviation 1993–2008). The tropical Pacific accounts for a large fraction of this global variability, closely tied to ENSO. Anomalies occur more than 6 months later in the East than in the West. The estimated amplitude and ENSO response are consistent with independent information from atmospheric oxygen data. Despite discrepancies in detail, this both supports the variability estimated from surface-ocean carbon data, and demonstrates the potential of the atmospheric oxygen signal to constrain ocean biogeochemical processes. The ocean variability estimated from surface-ocean carbon data can be used to improve land CO2 flux estimates from atmospheric inversions.

scholarly journals Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean <i>p</i>CO<sub>2</sub> Mapping intercomparison (SOCOM)

2015 ◽  
Vol 12 (23) ◽  
pp. 7251-7278 ◽  
Author(s):  
C. Rödenbeck ◽  
D. C. E. Bakker ◽  
N. Gruber ◽  
Y. Iida ◽  
A. R. Jacobson ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Atmospheric Oxygen ◽  
Co2 Flux ◽  
Process Models ◽  
Global Ocean ◽  
Co2 Uptake ◽  
Co2 Partial Pressure ◽  
Surface Ocean ◽  
Eastern Equatorial Pacific ◽  
Ocean Carbon

Abstract. Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global sea–air CO2 fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009), which is larger than simulated by biogeochemical process models. From a decadal perspective, the global ocean CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean CO2 sink estimated by the SOCOM ensemble is −1.75 PgC yr−1 (1992–2009), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trends.

scholarly journals Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean <i>p</i>CO<sub>2</sub> Mapping intercomparison (SOCOM)

2015 ◽  
Vol 12 (16) ◽  
pp. 14049-14104 ◽  
Author(s):  
C. Rödenbeck ◽  
D. C. E. Bakker ◽  
N. Gruber ◽  
Y. Iida ◽  
A. R. Jacobson ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Atmospheric Oxygen ◽  
Co2 Flux ◽  
Process Models ◽  
Co2 Uptake ◽  
Co2 Partial Pressure ◽  
Surface Ocean ◽  
Eastern Equatorial Pacific ◽  
First Results ◽  
Ocean Carbon

Abstract. Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global sea–air CO2 fluxes have been investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the Eastern equatorial Pacific. Despite considerable spead in the detailed variations, mapping methods with closer match to the data also tend to be more consistent with each other. Encouragingly, this includes mapping methods belonging to complementary types – taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global sea–air CO2 flux of 0.31 PgC yr−1 (standard deviation over 1992–2009), which is larger than simulated by biogeochemical process models. On a decadal perspective, the global CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to 2000. The weighted mean total ocean CO2 sink estimated by the SOCOM ensemble is consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trends.

scholarly journals Predicting near-term changes in ocean carbon uptake

2018 ◽  
Author(s):  
Nicole S. Lovenduski ◽  
Stephen G. Yeager ◽  
Keith Lindsay ◽  
Matthew C. Long
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Uptake ◽  
Surface Ocean ◽  
Predictive Skill ◽  
Decadal Variations ◽  
Near Term ◽  
Ocean Carbon ◽  
Carbon Dioxide Co2 ◽  
The Tropics

Abstract. Annual to decadal variations in air–sea fluxes of carbon dioxide (CO2) impact the global carbon cycle and climate system, and previous studies suggest that these variations may be predictable in the near-term. Here, we quantify and understand the sources of near-term (annual to decadal) predictability and predictive skill in air–sea CO2 flux on global and regional scales by analyzing output from a novel set of retrospective decadal forecasts of the Earth system. These initialized forecasts exhibit the potential to predict year-to-year variations in the globally-integrated air–sea CO2 flux up to ~ 7 years in advance. This initialized predictability exceeds the predictability obtained solely from foreknowledge of variations in external forcing or a simple persistence forecast. The near-term CO2 flux predictability is largely driven by predictability in the surface ocean partial pressure of CO2, which itself is a function of predictability in surface ocean dissolved inorganic carbon and alkalinity. Comparison with an observationally-based product suggests that the initialized forecasts exhibit moderate predictive skill in the tropics and subtropics, but low skill elsewhere. In the subantarctic Southern Ocean and northern North Atlantic, we find long-lasting initialized predictability that beats that derived from uninitialized and persistence forecasts. Our results suggest that year-to-year variations in ocean carbon uptake may be predictable well in advance, and establish a precedent for forecasting air–sea CO2 flux in the near future.

scholarly journals Predicting near-term variability in ocean carbon uptake

2019 ◽  
Vol 10 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Nicole S. Lovenduski ◽  
Stephen G. Yeager ◽  
Keith Lindsay ◽  
Matthew C. Long
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Uptake ◽  
Potential Predictability ◽  
Surface Ocean ◽  
Predictive Skill ◽  
Near Term ◽  
Ocean Carbon ◽  
Carbon Dioxide Co2 ◽  
Near Future

Abstract. Interannual variations in air–sea fluxes of carbon dioxide (CO2) impact the global carbon cycle and climate system, and previous studies suggest that these variations may be predictable in the near term (from a year to a decade in advance). Here, we quantify and understand the sources of near-term predictability and predictive skill in air–sea CO2 flux on global and regional scales by analyzing output from a novel set of retrospective decadal forecasts of an Earth system model. These forecasts exhibit the potential to predict year-to-year variations in the globally integrated air–sea CO2 flux several years in advance, as indicated by the high correlation of the forecasts with a model reconstruction of past CO2 flux evolution. This potential predictability exceeds that obtained solely from foreknowledge of variations in external forcing or a simple persistence forecast, with the longest-lasting forecast enhancement in the subantarctic Southern Ocean and the northern North Atlantic. Potential predictability in CO2 flux variations is largely driven by predictability in the surface ocean partial pressure of CO2, which itself is a function of predictability in surface ocean dissolved inorganic carbon and alkalinity. The potential predictability, however, is not realized as predictive skill, as indicated by the moderate to low correlation of the forecasts with an observationally based CO2 flux product. Nevertheless, our results suggest that year-to-year variations in ocean carbon uptake have the potential to be predicted well in advance and establish a precedent for forecasting air–sea CO2 flux in the near future.

scholarly journals Global surface-ocean <i>p</i><sup>CO<sub>2</sub></sup> and sea–air CO<sub>2</sub> flux variability from an observation-driven ocean mixed-layer scheme

Ocean Science ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 193-216 ◽  
Author(s):  
C. Rödenbeck ◽  
R. F. Keeling ◽  
D. C. E. Bakker ◽  
N. Metzl ◽  
A. Olsen ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Mixed Layer ◽  
Co2 Flux ◽  
Companion Paper ◽  
Diagnostic Model ◽  
Ocean Mixed Layer ◽  
Co2 Partial Pressure ◽  
Surface Ocean ◽  
Flux Variability ◽  
Global Surface

Abstract. A temporally and spatially resolved estimate of the global surface-ocean CO2 partial pressure field and the sea–air CO2 flux is presented, obtained by fitting a simple data-driven diagnostic model of ocean mixed-layer biogeochemistry to surface-ocean CO2 partial pressure data from the SOCAT v1.5 database. Results include seasonal, interannual, and short-term (daily) variations. In most regions, estimated seasonality is well constrained from the data, and compares well to the widely used monthly climatology by Takahashi et al. (2009). Comparison to independent data tentatively supports the slightly higher seasonal variations in our estimates in some areas. We also fitted the diagnostic model to atmospheric CO2 data. The results of this are less robust, but in those areas where atmospheric signals are not strongly influenced by land flux variability, their seasonality is nevertheless consistent with the results based on surface-ocean data. From a comparison with an independent seasonal climatology of surface-ocean nutrient concentration, the diagnostic model is shown to capture relevant surface-ocean biogeochemical processes reasonably well. Estimated interannual variations will be presented and discussed in a companion paper.

scholarly journals Surface Ocean CO<sub>2</sub> Atlas (SOCAT) gridded data products

2012 ◽  
Vol 5 (2) ◽  
pp. 781-804 ◽  
Author(s):  
C. L. Sabine ◽  
S. Hankin ◽  
H. Koyuk ◽  
D. C. E. Bakker ◽  
B. Pfeil ◽  
...  
Keyword(s):  
Gridded Data ◽  
Data Set ◽  
Surface Ocean ◽  
Marine Surface ◽  
Science Community ◽  
Ocean Carbon ◽  
To Come ◽  
Carbon Dioxide Co2 ◽  
Global Oceans ◽  
Global Data

Abstract. A well documented, publicly available, global data set for surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data from the global oceans and coastal seas, spanning four decades (1968–2007). The SOCAT gridded data is the second data product to come from the SOCAT project. Recognizing that some groups may have trouble working with millions of measurements, the SOCAT gridded product was generated to provide a robust regularly spaced fCO2 product with minimal spatial and temporal interpolation which should be easier to work with for many applications. Gridded SOCAT is rich with information that has not been fully explored yet, but also contains biases and limitations that the user needs to recognize and address.

scholarly journals Uncertainty of the global oceanic CO<sub>2</sub> uptake induced by wind forcing: quantification and spatial analysis

2017 ◽  
Author(s):  
Alizée Roobaert ◽  
Goulven G. Laruelle ◽  
Peter Landschützer ◽  
Pierre Regnier
Keyword(s):  
Wind Speed ◽  
Global Scale ◽  
Co2 Exchange ◽  
Calibration Coefficient ◽  
Transfer Velocity ◽  
K Value ◽  
Co2 Partial Pressure ◽  
The North ◽  
Time Period ◽  
Spatio Temporal

Abstract. Abstract. The calculation of the air-water CO2 exchange (FCO2) in the ocean not only depends on the gradient in CO2 partial pressure at the air-water interface but also on the parameterization of the gas exchange transfer velocity (k) and the choice of wind product. Here, we present regional and global-scale quantifications of the uncertainty in FCO2 induced by several widely used k-formulations and 4 wind speed data products (CCMP, ERA, NCEP1 and NCEP2). The analysis is performed at a 1° x 1° resolution using the sea surface pCO2 climatology generated by Landschützer et al. (2015) for the 1991–2011 period while the regional assessment relies on the segmentation proposed by the Regional Carbon Cycle Assessment and Processes (RECCAP) project. First, we use k-formulations derived from the global 14C inventory relying on a quadratic relationship between k and wind speed (k = c·U102, Sweeney et al., 2007; Takahashi et al., 2009; Wanninkhof, 2014) where c is a calibration coefficient and U10 is the wind speed measured 10 meters above the surface. Our results show that the range of global FCO2, calculated with these k-relationships, diverge by 12 % when using CCMP, ERA or NCEP1. Due to differences in the regional wind patterns, regional discrepancies in FCO2 are more pronounced than global. These global/regional differences significantly increase when using NCEP2 or other k-formulations which include earlier relationships (i.e. Wanninkhof, 1992; Wanninkhof et al., 2009) as well as numerous local/regional parameterizations derived experimentally. To minimize uncertainties associated with the choice of wind product it is possible to recalculate the coefficient c globally (hereafter called c*) for a given wind product and its spatio-temporal resolution, in order to match the last evaluation of the global k value. We thus performed these recalculations for each wind product at the resolution and time period of our study but the resulting global FCO2 estimates still diverge by 10 %. These results also reveal that the Equatorial Pacific, the North Atlantic and the Southern Ocean are the regions in which the choice of wind product will most strongly affect the estimation of the FCO2, even when using c*.

scholarly journals Surface Ocean CO<sub>2</sub> Atlas (SOCAT) gridded data products

2013 ◽  
Vol 5 (1) ◽  
pp. 145-153 ◽  
Author(s):  
C. L. Sabine ◽  
S. Hankin ◽  
H. Koyuk ◽  
D. C. E. Bakker ◽  
B. Pfeil ◽  
...  
Keyword(s):  
Gridded Data ◽  
Data Set ◽  
Surface Ocean ◽  
Temporal Interpolation ◽  
Science Community ◽  
Ocean Carbon ◽  
To Come ◽  
Carbon Dioxide Co2 ◽  
Global Oceans ◽  
Global Surface

Abstract. As a response to public demand for a well-documented, quality controlled, publically available, global surface ocean carbon dioxide (CO2) data set, the international marine carbon science community developed the Surface Ocean CO2 Atlas (SOCAT). The first SOCAT product is a collection of 6.3 million quality controlled surface CO2 data from the global oceans and coastal seas, spanning four decades (1968–2007). The SOCAT gridded data presented here is the second data product to come from the SOCAT project. Recognizing that some groups may have trouble working with millions of measurements, the SOCAT gridded product was generated to provide a robust, regularly spaced CO2 fugacity (fCO2) product with minimal spatial and temporal interpolation, which should be easier to work with for many applications. Gridded SOCAT is rich with information that has not been fully explored yet (e.g., regional differences in the seasonal cycles), but also contains biases and limitations that the user needs to recognize and address (e.g., local influences on values in some coastal regions).

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