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 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 Global CO<sub>2</sub> fluxes estimated from GOSAT retrievals of total column CO<sub>2</sub>

2013 ◽  
Vol 13 (17) ◽  
pp. 8695-8717 ◽  
Author(s):  
S. Basu ◽  
S. Guerlet ◽  
A. Butz ◽  
S. Houweling ◽  
O. Hasekamp ◽  
...  
Keyword(s):  
Bias Correction ◽  
Seasonal Cycle ◽  
Joint Inversion ◽  
Surface Fluxes ◽  
Global Land ◽  
Net Uptake ◽  
Surface Measurements ◽  
Source Sink ◽  
The Tropics ◽  
Total Column

Abstract. We present one of the first estimates of the global distribution of CO2 surface fluxes using total column CO2 measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT). We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO2 measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO2 time series at surface and TCCON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT XCO2 leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land–sea bias in our GOSAT XCO2 retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO2 yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO2 data alone. We show that assimilating the bias-corrected GOSAT data on top of surface CO2 data (a) reduces the estimated global land sink of CO2, and (b) shifts the terrestrial net uptake of carbon from the tropics to the extra-tropics. It is concluded that while GOSAT total column CO2 provide useful constraints for source–sink inversions, small spatiotemporal biases – beyond what can be detected using current validation techniques – have serious consequences for optimized fluxes, even aggregated over continental scales.

scholarly journals Preindustrial-Control and Twentieth-Century Carbon Cycle Experiments with the Earth System Model CESM1(BGC)

2014 ◽  
Vol 27 (24) ◽  
pp. 8981-9005 ◽  
Author(s):  
Keith Lindsay ◽  
Gordon B. Bonan ◽  
Scott C. Doney ◽  
Forrest M. Hoffman ◽  
David M. Lawrence ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Carbon Cycle ◽  
Time Scales ◽  
Seasonal Cycle ◽  
Earth System Model ◽  
Surface Fluxes ◽  
Atmospheric Co2 ◽  
System Model ◽  
Biogeochemical Model ◽  
Earth System

Abstract Version 1 of the Community Earth System Model, in the configuration where its full carbon cycle is enabled, is introduced and documented. In this configuration, the terrestrial biogeochemical model, which includes carbon–nitrogen dynamics and is present in earlier model versions, is coupled to an ocean biogeochemical model and atmospheric CO2 tracers. The authors provide a description of the model, detail how preindustrial-control and twentieth-century experiments were initialized and forced, and examine the behavior of the carbon cycle in those experiments. They examine how sea- and land-to-air CO2 fluxes contribute to the increase of atmospheric CO2 in the twentieth century, analyze how atmospheric CO2 and its surface fluxes vary on interannual time scales, including how they respond to ENSO, and describe the seasonal cycle of atmospheric CO2 and its surface fluxes. While the model broadly reproduces observed aspects of the carbon cycle, there are several notable biases, including having too large of an increase in atmospheric CO2 over the twentieth century and too small of a seasonal cycle of atmospheric CO2 in the Northern Hemisphere. The biases are related to a weak response of the carbon cycle to climatic variations on interannual and seasonal time scales and to twentieth-century anthropogenic forcings, including rising CO2, land-use change, and atmospheric deposition of nitrogen.

scholarly journals Assessing temporal clear-sky errors in assimilation of satellite CO<sub>2</sub> retrievals using a global transport model

2009 ◽  
Vol 9 (9) ◽  
pp. 3043-3048 ◽  
Author(s):  
K. D. Corbin ◽  
A. S. Denning ◽  
N. C. Parazoo
Keyword(s):  
Transport Model ◽  
Carbon Sources ◽  
Sampling Errors ◽  
Satellite Measurements ◽  
Sources And Sinks ◽  
Clear Sky ◽  
Temporal Sampling ◽  
Global Transport ◽  
Global Coverage ◽  
Total Column

Abstract. The Orbiting Carbon Observatory (OCO) and the Greenhouse gases Observing SATellite (GOSAT) will make global observations of the total column dry-air mole fraction of atmospheric CO2 (XCO2) starting in 2008. Although satellites have global coverage, XCO2 retrievals will be made only a few times each month over a given location and will only be sampled in clear conditions. Modelers will use XCO2 in atmospheric inversions to estimate carbon sources and sinks; however, if satellite measurements are used to represent temporal averages, modelers may incur temporal sampling errors. We investigate these errors using a global transport model. Temporal sampling errors vary with time and location, exhibit spatially coherent patterns, and are greatest over land and during summer. These errors often exceed 1 ppm and must be addressed in a data assimilation system by correct simulation of synoptic CO2 variations associated with cloud systems.

scholarly journals On the use of satellite-derived CH<sub>4</sub> : CO<sub>2</sub> columns in a joint inversion of CH<sub>4</sub> and CO<sub>2</sub> fluxes

2015 ◽  
Vol 15 (15) ◽  
pp. 8615-8629 ◽  
Author(s):  
S. Pandey ◽  
S. Houweling ◽  
M. Krol ◽  
I. Aben ◽  
T. Röckmann
Keyword(s):  
Joint Inversion ◽  
Surface Fluxes ◽  
Surface Measurement ◽  
Ratio Method ◽  
Co2 Fluxes ◽  
Hard Constraints ◽  
Surface Measurements ◽  
Total Column ◽  
Dual Tracer ◽  
Better Than

Abstract. We present a method for assimilating total column CH4 : CO2 ratio measurements from satellites for inverse modeling of CH4 and CO2 fluxes using the variational approach. Unlike conventional approaches, in which retrieved CH4 : CO2 are multiplied by model-derived total column CO2 and only the resulting CH4 is assimilated, our method assimilates the ratio of CH4 and CO2 directly and is therefore called the ratio method. It is a dual tracer inversion, in which surface fluxes of CH4 and CO2 are optimized simultaneously. The optimization of CO2 fluxes turns the hard constraint of prescribing model-derived CO2 fields into a weak constraint on CO2, which allows us to account for uncertainties in CO2. The method has been successfully tested in a synthetic inversion setup. We show that the ratio method is able to reproduce assumed true CH4 and CO2 fluxes starting from a prior, which is derived by perturbing the true fluxes randomly. We compare the performance of the ratio method with that of the traditional proxy approach and the use of only surface measurements for estimating CH4 fluxes. Our results confirm that the optimized CH4 fluxes are sensitive to the treatment of CO2, and that hard constraints on CO2 may significantly compromise results that are obtained for CH4. We find that the relative performance of ratio and proxy methods have a regional dependence. The ratio method performs better than the proxy method in regions where the CO2 fluxes are most uncertain. However, both ratio and proxy methods perform better than the surface-measurement-only inversion, confirming the potential of spaceborne measurements for accurately determining fluxes of CH4 and other greenhouse gases (GHGs).

scholarly journals The potential of OCO-2 data to reduce the uncertainties in CO<sub>2</sub> surface fluxes over Australia using a variational assimilation scheme

2019 ◽  
Author(s):  
Yohanna Villalobos ◽  
Peter Rayner ◽  
Steven Thomas ◽  
Jeremy Silver
Keyword(s):  
Dispersion Model ◽  
Surface Fluxes ◽  
Co2 Fluxes ◽  
Error Statistics ◽  
Satellite Measurements ◽  
Error Covariance ◽  
Horizontal Grid ◽  
Assimilation Scheme ◽  
Data Assimilation System ◽  
Total Column

Abstract. This paper addresses the question of how much uncertainties in CO2 fluxes over Australia can be reduced by assimilation of total-column carbon dioxide retrievals from the Orbiting Carbon Observatory-2 (OCO-2) satellite instrument. We apply a four-dimensional variational data assimilation system, based around the Community Multiscale Air Quality (CMAQ) transport-dispersion model. We ran a series of observing system simulation experiments to estimate posterior error statistics of optimized monthly mean CO2 fluxes in Australia. Our assimilations were run with a horizontal grid resolution of 81 km using OCO-2 data for 2015. We found that on average, the total Australia flux uncertainty was reduced by up to 40 % using only OCO-2 nadir measurements. Using both nadir and glint satellite measurements produces uncertainty reductions up to 80 %, which represents 0.55 PgC y−1 for the whole continent. Uncertainty reductions were found to be greatest in the more productive regions of Australia. The choice of the correlation structure in the prior error covariance was found to play a large role in distributing information from the observations. Overall the results suggest that flux inversions at this unusually fine scale will yield useful information on the Australian carbon cycle.

scholarly journals Global CO<sub>2</sub> fluxes estimated from GOSAT retrievals of total column CO<sub>2</sub>

2013 ◽  
Vol 13 (2) ◽  
pp. 4535-4600 ◽  
Author(s):  
S. Basu ◽  
S. Guerlet ◽  
A. Butz ◽  
S. Houweling ◽  
O. Hasekamp ◽  
...  
Keyword(s):  
Bias Correction ◽  
Seasonal Cycle ◽  
Joint Inversion ◽  
Surface Fluxes ◽  
Global Land ◽  
Net Uptake ◽  
Surface Measurements ◽  
Source Sink ◽  
The Tropics ◽  
Total Column

Abstract. We present one of the first estimates of the global distribution of CO2 surface fluxes using total column CO2 measurements retrieved from the Greenhouse gases Observing SATellite (GOSAT). We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO2 measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO2 time series at surface and TCCON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT XCO2 leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land-sea bias in our GOSAT XCO2 retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO2 yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO2 data alone. We show that assimilating the bias-corrected GOSAT data on top of surface CO2 data (a) reduces the estimated global land sink of CO2, and (b) shifts the terrestrial net uptake of carbon from the tropics to the extra-tropics. It is concluded that while GOSAT total column CO2 provide useful constraints for source-sink inversions, small spatiotemporal biases – beyond what can be detected using current validation techniques – have serious consequences for optimized fluxes, even aggregated over continental scales.

Inverse modelling of global methane emissions using TROPOMI

2021 ◽  
Author(s):  
Jacob van Peet ◽  
Sander Houweling ◽  
Julia Marshall ◽  
Tonatiuh Nunez Ramirez ◽  
Arjo Segers
Keyword(s):  
Bias Correction ◽  
A Priori ◽  
Correction Method ◽  
Methane Emissions ◽  
Surface Fluxes ◽  
Inverse Modelling ◽  
Satellite Measurements ◽  
Mixing Ratios ◽  
Surface Measurements ◽  
Total Column

&lt;p&gt;This study investigates the use of total column methane measurements from the TROPOMI satellite instrument for estimating the global sources and sinks of methane. A bias correction method has been developed based on a comparison between the satellite measurements and an inversion using surface measurements only, building on the experience using GOSAT data. The bias correction is applied to the satellite measurements prior to the use of the data in the inversion. Results will be shown of inversions using the TM5 4D-VAR and CarboScope inverse modelling systems applied to two years of TROPOMI data. The inversion-optimized methane mixing ratios are inter-compared and validated against independent surface (WMO-GAW), Aircraft (ATom) and total column (TCCON) observations. The derived methane fluxes are aggregated over selected geographic regions, to compare the optimised methane emissions from TM5-4DVAR, CarboScope, and GOSAT inversions from the Copernicus Atmospheric Monitoring Service.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Methane surface mixing ratios derived from the TROPOMI inversion show a good agreement with the surface measurements in general. Near areas with high aerosol optical thickness (e.g. the Sahara) we see significant adjustments in the surface fluxes, compensating for model-data differences, pointing to influences of residual uncorrected systematic errors in the data. The total column comparison with TCCON measurements shows a slight North-South bias gradient. These finding are investigated in further detail by comparing results using the operational retrieval product to the use of the scientific RemoTeC and WFMD retrievals. Encouragingly, both the TM5 and CarboScope inversions show similar increments in the aggregated fluxes over time. The seasonal cycle in the posterior fluxes is different from that of the a a priori fluxes, which were the same for both inversion systems.&lt;/p&gt;

scholarly journals Assessing temporal clear-sky errors in assimilation of satellite CO<sub>2</sub> retrievals using a global transport model

2008 ◽  
Vol 8 (4) ◽  
pp. 12887-12901
Author(s):  
K. D. Corbin ◽  
A. S. Denning ◽  
N. C. Parazoo
Keyword(s):  
Transport Model ◽  
Carbon Sources ◽  
Sampling Errors ◽  
Satellite Measurements ◽  
Sources And Sinks ◽  
Clear Sky ◽  
Temporal Sampling ◽  
Global Transport ◽  
Global Coverage ◽  
Total Column

Abstract. The Orbiting Carbon Observatory (OCO) and the Greenhouse gases Observing SATellite (GOSAT) will make global observations of the total column dry-air mole fraction of atmospheric CO2 (XCO2) starting in 2008. Although satellites have global coverage, XCO2 retrieval will be made only a few times each month over a given location and will only be sampled in clear conditions. Modelers will use XCO2 in atmospheric inversions to estimate carbon sources and sinks; however, if satellite measurements are used to represent temporal averages, modelers may incur temporal sampling errors. We investigate these errors using a global transport model. Temporal sampling errors vary with time and location, exhibit spatially coherent patterns, and are greatest over land and during summer. These errors often exceed 1 ppm and must be addressed in a data assimilation system by correct simulation of synoptic CO2 variations associated with cloud systems.

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
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