scholarly journals An estimate of monthly global emissions of anthropogenic CO2: Impact on the seasonal cycle of atmospheric CO2

2008 ◽  
Vol 113 (G1) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. J. Erickson ◽  
R. T. Mills ◽  
J. Gregg ◽  
T. J. Blasing ◽  
F. M. Hoffman ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Atmospheric Co2 ◽  
Anthropogenic Co2 ◽  
Global Emissions

scholarly journals Does atmospheric CO<sub>2</sub> seasonality play an important role in governing the air-sea flux of CO<sub>2</sub>?

2012 ◽  
Vol 9 (6) ◽  
pp. 2311-2323 ◽  
Author(s):  
P. R. Halloran
Keyword(s):  
Wind Speed ◽  
Sea Ice ◽  
Seasonal Cycle ◽  
Co2 Flux ◽  
Atmospheric Co2 ◽  
Seasonal Cycles ◽  
Earth System ◽  
Model Simulations ◽  
Anthropogenic Co2 ◽  
The Impact

Abstract. The amplitude, phase, and form of the seasonal cycle of atmospheric CO2 concentrations varies on many time and space scales (Peters et al., 2007). Intra-annual CO2 variation is primarily driven by seasonal uptake and release of CO2 by the terrestrial biosphere (Machta et al., 1977; Buchwitz et al., 2007), with a small (Cadule et al., 2010; Heimann et al., 1998), but potentially changing (Gorgues et al., 2010) contribution from the ocean. Variability in the magnitude, spatial distribution, and seasonal drivers of terrestrial net primary productivity (NPP) will be induced by, amongst other factors, anthropogenic CO2 release (Keeling et al., 1996), land-use change (Zimov et al., 1999) and planetary orbital variability, and will lead to changes in CO2atm seasonality. Despite CO2atm seasonality being a dynamic and prominent feature of the Earth System, its potential to drive changes in the air-sea flux of CO2 has not previously (to the best of my knowledge) been explored. It is important that we investigate the impact of CO2atm seasonality change, and the potential for carbon-cycle feedbacks to operate through the modification of the CO2atm seasonal cycle, because the decision had been made to prescribe CO2atm concentrations (rather than emissions) within model simulations for the fifth IPCC climate assessment (Taylor et al., 2009). In this study I undertake ocean-model simulations within which different magnitude CO2atm seasonal cycles are prescribed. These simulations allow me to examine the effect of a change in CO2atm seasonal cycle magnitude on the air-sea CO2 flux. I then use an off-line model to isolate the drivers of the identified air-sea CO2 flux change, and propose mechanisms by which this change may come about. Three mechanisms are identified by which co-variability of the seasonal cycles in atmospheric CO2 concentration, and seasonality in sea-ice extent, wind-speed and ocean temperature, could potentially lead to changes in the air-sea flux of CO2 at mid-to-high latitudes. The sea-ice driven mechanism responds to an increase in CO2atm seasonality by pumping CO2 into the ocean, the wind-speed and solubility-driven mechanisms, by releasing CO2 from the ocean (in a relative sense). The relative importance of the mechanisms will be determined by, amongst other variables, the seasonal extent of sea-ice. To capture the described feedbacks within earth system models, CO2atm concentrations must be allowed to evolve freely, forced only by anthropogenic emissions rather than prescribed CO2atm concentrations; however, time-integrated ocean simulations imply that the cumulative net air-sea flux could be at most equivalent to a few ppm CO2atm. The findings presented here suggest that, at least under pre-industrial conditions, the prescription of CO2atm concentrations rather than emissions within simulations will have little impact on the marine anthropogenic CO2 sink.

scholarly journals The seasonal cycle of atmospheric CO2: A study based on the NCAR Community Climate Model (CCM2)

1996 ◽  
Vol 101 (D10) ◽  
pp. 15079-15097 ◽  
Author(s):  
D. J. Erickson ◽  
P. J. Rasch ◽  
P. P. Tans ◽  
P. Friedlingstein ◽  
P. Ciais ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Climate Model ◽  
Atmospheric Co2 ◽  
Community Climate Model ◽  
Community Climate

scholarly journals Substrate limitations for heterotrophs: Implications for models that estimate the seasonal cycle of atmospheric CO2

1996 ◽  
Vol 10 (4) ◽  
pp. 585-602 ◽  
Author(s):  
James T. Randerson ◽  
Matthew V. Thompson ◽  
Carolyn M. Malmstrom ◽  
Christopher B. Field ◽  
Inez Y. Fung
Keyword(s):  
Seasonal Cycle ◽  
Atmospheric Co2

Mechanisms of Northern Tropical Atlantic Variability and Response to CO2 Doubling

2007 ◽  
Vol 20 (11) ◽  
pp. 2691-2705 ◽  
Author(s):  
Wim-Paul Breugem ◽  
Wilco Hazeleger ◽  
Reindert J. Haarsma
Keyword(s):  
Moisture Transport ◽  
Seasonal Cycle ◽  
General Circulation ◽  
Circulation Model ◽  
Atmospheric Co2 ◽  
Boreal Winter ◽  
Tropical Atlantic ◽  
Wes Feedback ◽  
Meridional Mode ◽  
Northern Tropical Atlantic

Abstract A model study has been made of the mechanisms of the meridional mode in the northern tropical Atlantic (NTA) and the response to a doubling of atmospheric CO2. The numerical model consists of an atmospheric general circulation model (GCM) coupled to a passive mixed layer model for the ocean. Results from two simulations are shown: a control run with present-day atmospheric CO2 and a run with a doubled CO2 concentration. The results from the control run show that the wind–evaporation–SST (WES) feedback is confined to the deep NTA. Furthermore, the temporal evolution of the meridional mode is phase locked with the seasonal cycle of the climatological intertropical convergence zone (CITCZ). The WES feedback is positive in boreal winter and spring when the CITCZ is located close to the equator but negative in summer and fall when the CITCZ shifts toward the north of the deep NTA. Similarly, the damping of the SST anomalies in the deep NTA by moisture-induced evaporation anomalies is much stronger in summer and fall than in winter and spring, related to a change in anomalous moisture transport. The results from the double-CO2 run show a substantial northward shift of the CITCZ in boreal winter and spring but little change in summer and fall. The change in the CITCZ can be explained by strong warming at the high northern latitudes in combination with a seasonally dependent WES feedback with accompanying changes in moisture transport in the deep NTA. The latter indicates that the change in the CITCZ is subject to phase locking with the seasonal cycle of the CITCZ itself. The meridional mode in the double-CO2 run weakens by 10%–20%. This originates from the weakening of the positive WES feedback in the deep NTA, which in turn is attributed to the northward shift of the CITCZ; because in the double-CO2 run the CITCZ stays south of the deep NTA for a shorter time period, the positive WES feedback in the deep NTA acts less long, and damping by moisture-induced evaporation anomalies starts earlier than in the control run.

scholarly journals Regional Impacts of Climate Change and Atmospheric CO2 on Future Ocean Carbon Uptake: A Multimodel Linear Feedback Analysis

2011 ◽  
Vol 24 (9) ◽  
pp. 2300-2318 ◽  
Author(s):  
Tilla Roy ◽  
Laurent Bopp ◽  
Marion Gehlen ◽  
Birgit Schneider ◽  
Patricia Cadule ◽  
...  
Keyword(s):  
Climate Change ◽  
North Atlantic Ocean ◽  
Climate Change Impacts ◽  
Atmospheric Co2 ◽  
Linear Feedback ◽  
Co2 Uptake ◽  
Co2 Solubility ◽  
Feedback Analysis ◽  
Anthropogenic Co2 ◽  
Atmospheric Co2 Concentrations

Abstract The increase in atmospheric CO2 over this century depends on the evolution of the oceanic air–sea CO2 uptake, which will be driven by the combined response to rising atmospheric CO2 itself and climate change. Here, the future oceanic CO2 uptake is simulated using an ensemble of coupled climate–carbon cycle models. The models are driven by CO2 emissions from historical data and the Special Report on Emissions Scenarios (SRES) A2 high-emission scenario. A linear feedback analysis successfully separates the regional future (2010–2100) oceanic CO2 uptake into a CO2-induced component, due to rising atmospheric CO2 concentrations, and a climate-induced component, due to global warming. The models capture the observation-based magnitude and distribution of anthropogenic CO2 uptake. The distributions of the climate-induced component are broadly consistent between the models, with reduced CO2 uptake in the subpolar Southern Ocean and the equatorial regions, owing to decreased CO2 solubility; and reduced CO2 uptake in the midlatitudes, owing to decreased CO2 solubility and increased vertical stratification. The magnitude of the climate-induced component is sensitive to local warming in the southern extratropics, to large freshwater fluxes in the extratropical North Atlantic Ocean, and to small changes in the CO2 solubility in the equatorial regions. In key anthropogenic CO2 uptake regions, the climate-induced component offsets the CO2-induced component at a constant proportion up until the end of this century. This amounts to approximately 50% in the northern extratropics and 25% in the southern extratropics and equatorial regions. Consequently, the detection of climate change impacts on anthropogenic CO2 uptake may be difficult without monitoring additional tracers, such as oxygen.

scholarly journals First direct observation of the atmospheric CO<sub>2</sub> year-to-year increase from space

2007 ◽  
Vol 7 (16) ◽  
pp. 4249-4256 ◽  
Author(s):  
M. Buchwitz ◽  
O. Schneising ◽  
J. P. Burrows ◽  
H. Bovensmann ◽  
M. Reuter ◽  
...  
Keyword(s):  
Seasonal Cycle ◽  
Current Knowledge ◽  
Surface Fluxes ◽  
Atmospheric Co2 ◽  
Surface Measurement ◽  
Spectral Radiance ◽  
Satellite Measurements ◽  
Temporal Sampling ◽  
Northern Hemispheric ◽  
Total Column

Abstract. The reliable prediction of future atmospheric CO2 concentrations and associated global climate change requires an adequate understanding of the CO2 sources and sinks. The sparseness of the existing surface measurement network limits current knowledge about the global distribution of CO2 surface fluxes. The retrieval of CO2 total vertical columns from satellite observations is predicted to improve this situation. Such an application however requires very high accuracy and precision. We report on retrievals of the column-averaged CO2 dry air mole fraction, denoted XCO2, from the near-infrared nadir spectral radiance and solar irradiance measurements of the SCIAMACHY satellite instrument between 2003 and 2005. We focus on northern hemispheric large scale CO2 features such as the CO2 seasonal cycle and show - for the first time - that the atmospheric annual increase of CO2 can be directly observed using satellite measurements of the CO2 total column. The satellite retrievals are compared with global XCO2 obtained from NOAA's CO2 assimilation system CarbonTracker taking into account the spatio-temporal sampling and altitude sensitivity of the satellite data. We show that the measured CO2 year-to-year increase agrees within about 1 ppm/year with CarbonTracker. We also show that the latitude dependent amplitude of the northern hemispheric CO2 seasonal cycle agrees with CarbonTracker within about 2 ppm with the retrieved amplitude being systematically larger. The analysis demonstrates that it is possible using satellite measurements of the CO2 total column to retrieve information on the atmospheric CO2 on the level of a few parts per million.

scholarly journals Evaluating two soil carbon models within a global land surface model using surface and spaceborne observations of atmospheric CO<sub>2</sub> mole fractions

2020 ◽  
Author(s):  
Tea Thum ◽  
Julia E. S. M. Nabel ◽  
Aki Tsuruta ◽  
Tuula Aalto ◽  
Edward J. Dlugokencky ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Land Surface ◽  
Seasonal Cycle ◽  
Land Surface Model ◽  
Carbon Stocks ◽  
Atmospheric Co2 ◽  
Surface Model ◽  
Global Land ◽  
Soil Carbon Stocks ◽  
Surface Observations

Abstract. The trajectories of soil carbon (C) in the changing climate are of utmost importance, as soil carbon is a substantial carbon storage with a large potential to impact the atmospheric carbon dioxide (CO2) burden. Atmospheric CO2 observations integrate all processes affecting C exchange between the surface and the atmosphere. Therefore they provide a benchmark for carbon cycle models. We evaluated two distinct soil carbon models (CBALANCE and YASSO) that were implemented to a global land surface model (JSBACH) against atmospheric CO2 observations. We transported the biospheric carbon fluxes obtained by JSBACH using the atmospheric transport model TM5 to obtain atmospheric CO2. We then compared these results with surface observations from Global Atmosphere Watch (GAW) stations as well as with column XCO2 retrievals from the GOSAT satellite. The seasonal cycles of atmospheric CO2 estimated by the two different soil models differed. The estimates from the CBALANCE soil model were more in line with the surface observations at low latitudes (0 N–45 N) with only 1 % bias in the seasonal cycle amplitude (SCA), whereas YASSO was underestimating the SCA in this region by 32 %. YASSO gave more realistic seasonal cycle amplitudes of CO2 at northern boreal sites (north of 45 N) with underestimation of 15 % compared to 30 % overestimation by CBALANCE. Generally, the estimates from CBALANCE were more successful in capturing the seasonal patterns and seasonal cycle amplitudes of atmospheric CO2 even though it overestimated soil carbon stocks by 225 % (compared to underestimation of 36 % by YASSO) and its predictions of the global distribution of soil carbon stocks was unrealistic. The reasons for these differences in the results are related to the different environmental drivers and their functional dependencies of these two soil carbon models. In the tropical region the YASSO model showed earlier increase in season of the heterotophic respiration since it is driven by precipitation instead of soil moisture as CBALANCE. In the temperate and boreal region the role of temperature is more dominant. There the heterotophic respiration from the YASSO model had larger annual variability, driven by air temperature, compared to the CBALANCE which is driven by soil temperature. The results underline the importance of using sub-yearly data in the development of soil carbon models when they are used in shorter than annual time scales.

scholarly journals First direct observation of the atmospheric CO<sub>2</sub> year-to-year increase from space

2007 ◽  
Vol 7 (3) ◽  
pp. 6719-6735 ◽  
Author(s):  
M. Buchwitz ◽  
O. Schneising ◽  
J. P. Burrows ◽  
H. Bovensmann ◽  
J. Notholt
Keyword(s):  
Seasonal Cycle ◽  
Large Scale ◽  
Current Knowledge ◽  
Global Climate ◽  
Surface Fluxes ◽  
Atmospheric Co2 ◽  
Surface Measurement ◽  
Satellite Measurements ◽  
Vertical Column ◽  
Northern Hemispheric

Abstract. The reliable prediction of future atmospheric CO2 concentrations and associated global climate change requires an adequate understanding of the CO2 sources and sinks. The sparseness of the existing surface measurement network limits current knowledge about the global distribution of CO2 surface fluxes. The retrieval of the CO2 total vertical column from satellite observations is predicted to improve this situation. Such an application however requires very high accuracy and precision on the order of 1% (4 ppm) or better. We report on retrievals of the column-averaged CO2 dry air mole fraction, denoted XCO2, from the measurements of the SCIAMACHY satellite instrument between 2003 and 2005. We focus on northern hemispheric large scale CO2 features such as the CO2 seasonal cycle and show – for the first time – that the atmospheric annual increase of CO2 can be directly observed using satellite measurements of the CO2 total column. The satellite retrievals are compared with the global assimilation system CarbonTracker and with local surface CO2 measurements based on weekly flask sampling. We show that the year-to-year CO2 increase as determined from the satellite data agrees with the reference data within about 1 ppm/year. We also show that the CO2 seasonal cycle over northern hemispheric low and mid latitudes can be retrieved with a precision of about 2 ppm. The results presented here demonstrate that it is possible using satellite measurements to retrieved information on the atmospheric CO2 on the level of a few parts per million.

scholarly journals A 1-D examination of decadal air–sea re-equilibration induced ocean surface anthropogenic CO<sub>2</sub> accumulation: present status, changes from 1960s to 2000s, and future scenarios

2014 ◽  
Vol 11 (7) ◽  
pp. 11509-11532
Author(s):  
W.-D. Zhai ◽  
H.-D. Zhao
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Accumulation Rate ◽  
Ocean Surface ◽  
Atmospheric Co2 ◽  
Global Ocean ◽  
Surface Ocean ◽  
Anthropogenic Co2 ◽  
Year 2000 ◽  
Global Mean ◽  
System Chemistry

Abstract. Based upon the well-understood carbonate system chemistry over global ocean surface (above the wintertime thermocline and shallower than upper 100 m), we investigated potentials of wintertime ocean surface DIC (dissolved inorganic carbon) to rise in response to the decadal air–sea re-equilibration, and the corresponding anthropogenic CO2 accumulation rates. For a reference year 2000, the potentials of wintertime DIC to rise in response to the rising atmospheric CO2 mole fraction ranged from 0.28 to 0.70 μmol kg−1 ppm−1 (ppm = parts of CO2 per million dry air) over the global open ocean surface, while the global mean wintertime surface DIC increase rate was close to 1.0 μmol kg−1 yr−1. The decadal anthropogenic CO2 accumulation rate within the surface ocean was estimated at 0.31 × 1015 g C yr−1 around the reference year 2000, accounting for a non-negligible component (likely 12 to 14%) of the recent oceanic sink for anthropogenic CO2. From 1960s to 2000s, this rate likely increased by 47% due to the accelerated atmospheric CO2 rise. However, the ocean surface anthropogenic CO2 accumulation potential under a unit atmospheric CO2 rise may have declined by 16% during the same period.

scholarly journals Terrestrial carbon sink observed from space: variation of growth rates and seasonal cycle amplitudes in response to interannual surface temperature variability

2014 ◽  
Vol 14 (1) ◽  
pp. 133-141 ◽  
Author(s):  
O. Schneising ◽  
M. Reuter ◽  
M. Buchwitz ◽  
J. Heymann ◽  
H. Bovensmann ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Growth Rates ◽  
Seasonal Cycle ◽  
Temperature Anomaly ◽  
Carbon Sink ◽  
Atmospheric Co2 ◽  
Climate Feedback ◽  
Terrestrial Carbon ◽  
Terrestrial Carbon Sink ◽  
The Impact

Abstract. The terrestrial biosphere is currently acting as a net carbon sink on the global scale, exhibiting significant interannual variability in strength. To reliably predict the future strength of the land sink and its role in atmospheric CO2 growth, the underlying biogeochemical processes and their response to a changing climate need to be well understood. In particular, better knowledge of the impact of key climate variables such as temperature or precipitation on the biospheric carbon reservoir is essential. It is demonstrated using nearly a decade of SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) nadir measurements that years with higher temperatures during the growing season can be robustly associated with larger growth rates in atmospheric CO2 and smaller seasonal cycle amplitudes for northern mid-latitudes. We find linear relationships between warming and CO2 growth as well as seasonal cycle amplitude at the 98% significance level. This suggests that the terrestrial carbon sink is less efficient at higher temperatures during the analysed time period. Unless the biosphere has the ability to adapt its carbon storage under warming conditions in the longer term, such a temperature response entails the risk of potential future sink saturation via a positive carbon-climate feedback. Quantitatively, the covariation between the annual CO2 growth rates derived from SCIAMACHY data and warm season surface temperature anomaly amounts to 1.25 ± 0.32 ppm yr−1 K−1 for the Northern Hemisphere, where the bulk of the terrestrial carbon sink is located. In comparison, this relationship is less pronounced in the Southern Hemisphere. The covariation of the seasonal cycle amplitudes retrieved from satellite measurements and temperature anomaly is −1.30 ± 0.31 ppm K−1 for the north temperate zone. These estimates are consistent with those from the CarbonTracker data assimilated CO2 data product, indicating that the temperature dependence of the model surface fluxes is realistic.

Sign in / Sign up

Export Citation Format

Share Document