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 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 Predicting the variable ocean carbon sink

2019 ◽  
Vol 5 (4) ◽  
pp. eaav6471 ◽  
Author(s):  
H. Li ◽  
T. Ilyina ◽  
W. A. Müller ◽  
P. Landschützer
Keyword(s):  
Carbon Sink ◽  
System Model ◽  
Carbon Uptake ◽  
Prediction System ◽  
Earth System ◽  
Temperature Variations ◽  
The Past ◽  
Predictive Skill ◽  
Decadal Variations ◽  
Ocean Carbon

Strong decadal variations in the oceanic uptake of carbon dioxide (CO2) observed over the past three decades challenge our ability to predict the strength of the ocean carbon sink. By assimilating atmospheric and oceanic observational data products into an Earth system model–based decadal prediction system, we can reproduce the observed variations of the ocean carbon uptake globally. We find that variations of the ocean CO2 uptake are predictable up to 2 years in advance globally, albeit there is evidence for a higher predictive skill up to 5 years regionally. We further suggest that while temperature variations largely determine shorter-term (<3 years) predictability, nonthermal drivers are responsible for longer-term (>3 years) predictability, especially at high latitudes.

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 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).

scholarly journals CO<sub>2</sub> perturbation experiments: similarities and differences between dissolved inorganic carbon and total alkalinity manipulations

2009 ◽  
Vol 6 (2) ◽  
pp. 4441-4462 ◽  
Author(s):  
K. G. Schulz ◽  
J. Barcelos e Ramos ◽  
R. E. Zeebe ◽  
U. Riebesell
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Carbonate Chemistry ◽  
Surface Ocean ◽  
Seawater Carbonate Chemistry ◽  
Similarities And Differences ◽  
Carbon Dioxide Co2

Abstract. Increasing atmospheric carbon dioxide (CO2) through human activities and invasion of anthropogenic CO2 into the surface ocean alters the seawater carbonate chemistry, increasing CO2 and bicarbonate (HCO3

scholarly journals A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink

2013 ◽  
Vol 10 (11) ◽  
pp. 7793-7815 ◽  
Author(s):  
P. Landschützer ◽  
N. Gruber ◽  
D. C. E. Bakker ◽  
U. Schuster ◽  
S. Nakaoka ◽  
...  
Keyword(s):  
Neural Network ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
Carbon Sink ◽  
Co2 Flux ◽  
South Atlantic ◽  
Sea Surface ◽  
Series Data ◽  
Surface Ocean ◽  
Ocean Carbon

Abstract. The Atlantic Ocean is one of the most important sinks for atmospheric carbon dioxide (CO2), but this sink has been shown to vary substantially in time. Here we use surface ocean CO2 observations to estimate this sink and the temporal variability from 1998 through 2007 in the Atlantic Ocean. We benefit from (i) a continuous improvement of the observations, i.e. the Surface Ocean CO2 Atlas (SOCAT) v1.5 database and (ii) a newly developed technique to interpolate the observations in space and time. In particular, we use a two-step neural network approach to reconstruct basin-wide monthly maps of the sea surface partial pressure of CO2 (pCO2) at a resolution of 1° × 1°. From those, we compute the air–sea CO2 flux maps using a standard gas exchange parameterization and high-resolution wind speeds. The neural networks fit the observed pCO2 data with a root mean square error (RMSE) of about 10 μatm and with almost no bias. A check against independent time-series data and new data from SOCAT v2 reveals a larger RMSE of 22.8 μatm for the entire Atlantic Ocean, which decreases to 16.3 μatm for data south of 40° N. We estimate a decadal mean uptake flux of −0.45 ± 0.15 Pg C yr−1 for the Atlantic between 44° S and 79° N, representing the sum of a strong uptake north of 18° N (−0.39 ± 0.10 Pg C yr−1), outgassing in the tropics (18° S–18° N, 0.11 ± 0.07 Pg C yr−1), and uptake in the subtropical/temperate South Atlantic south of 18° S (−0.16 ± 0.06 Pg C yr−1), consistent with recent studies. The strongest seasonal variability of the CO2 flux occurs in the temperature-driven subtropical North Atlantic, with uptake in winter and outgassing in summer. The seasonal cycle is antiphased in the subpolar latitudes relative to the subtropics largely as a result of the biologically driven winter-to-summer drawdown of CO2. Over the 10 yr analysis period (1998 through 2007), sea surface pCO2 increased faster than that of the atmosphere in large areas poleward of 40° N, while in other regions of the North Atlantic the sea surface pCO2 increased at a slower rate, resulting in a barely changing Atlantic carbon sink north of the Equator (−0.01 ± 0.02 Pg C yr−1 decade−1). Surface ocean pCO2 increased at a slower rate relative to atmospheric CO2 over most of the Atlantic south of the Equator, leading to a substantial trend toward a stronger CO2 sink for the entire South Atlantic (−0.14 ± 0.02 Pg C yr−1 decade−1). In contrast to the 10 yr trends, the Atlantic Ocean carbon sink varies relatively little on inter-annual timescales (±0.04 Pg C yr−1; 1 σ).

scholarly journals Impact of peatlands on carbon dioxide (CO<sub>2</sub>) emissions from the Rajang River and Estuary, Malaysia

2018 ◽  
Author(s):  
Denise Müller-Dum ◽  
Thorsten Warneke ◽  
Tim Rixen ◽  
Moritz Müller ◽  
Antje Baum ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Co2 Flux ◽  
Southeast Asian ◽  
Dry Season ◽  
Carbon Dioxide Partial Pressure ◽  
Wet Season ◽  
Peat Deposits ◽  
Carbon Dioxide Co2

Abstract. Tropical peat-draining rivers are known as potentially large sources of carbon dioxide (CO2) to the atmosphere due to high loads of carbon they receive from surrounding soils. However, not many seasonally resolved data are available, limiting our understanding of these systems. We report the first measurements of carbon dioxide partial pressure (pCO2) in the Rajang River and Estuary, the longest river in Malaysia. The Rajang River catchment is characterized by extensive peat deposits found in the delta region, and by human impact such as logging, land use and river damming. pCO2 averaged 2919 ± 573 µatm during the wet season and 2732 ± 443 µatm during the dry season. This is at the low end of reported values for Southeast Asian peat-draining rivers, but higher than values reported for Southeast Asian rivers that do not flow through peat deposits. However, dissolved inorganic carbon (DIC) and δ13C-DIC data did not suggest that peatlands were an important source of inorganic carbon to the river, with an average DIC concentration of 203.9 ± 59.6 µmol L−1 and an average δ13C-DIC of −8.06 ± 1.90 ‰. Also, compared to rivers with similar peat coverage, the pCO2 in the Rajang was rather low. Thus, we suggest that peat coverage is, by itself, insufficient as sole predictor of CO2 emissions from peat-draining rivers, and that other factors, like the spatial distribution of peat in the catchment and pH, need to be considered as well. In the Rajang River, peatlands probably do not contribute much to the CO2 flux due to the proximity of the peatlands to the coast. CO2 fluxes to the atmosphere were 2.28 ± 0.52 gC m−2 d−1 (wet season) and 2.45 ± 0.45 gC m−2 d−1 (dry season), making the Rajang River a moderate source of carbon to the atmosphere.

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