The European CO2 Monitoring Mission: observing anthropogenic greenhouse gas emissions from space

Sierk, B.; Bézy, Jean‐Loup; Löscher, Armin; Meijer, Yasjka

doi:10.1117/12.2535941

Cited by 48 publications

(39 citation statements)

References 16 publications

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“…Additional work is needed to validate the retrieved wind speed from OCO-3, but the instrument has characteristics very similar to OCO-2 and thus it is likely that the conclusions found here are also valid for OCO-3. Finally, this work will inform a number of future OCO-2-like instruments, such as MicroCarb (Buil et al, 2011) and the ambitious Copernicus CO 2 Monitoring Mission (Sierk et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Retrieved wind speed from the Orbiting Carbon Observatory-2

Nelson¹,

Eldering²,

Crisp³

et al. 2020

Preprint

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Abstract. Satellite measurements of surface wind speed over the ocean inform a wide variety of scientific pursuits. While both active and passive microwave sensors are traditionally used to detect surface wind speed over water surfaces, measurements of reflected sunlight in the near-infrared made by the Orbiting Carbon Observatory-2 (OCO-2) are also sensitive to the wind speed. In this work, retrieved wind speeds from OCO-2 glint measurements are validated against the Advanced Microwave Scanning Radiometer-2 (AMSR2). Both sensors are in the international Afternoon Constellation, allowing for a large number of co-located observations. Several different OCO-2 retrieval algorithm modifications are tested, with the most successful being a single-band Cox-Munk-only model. Using this, we find excellent agreement between the two sensors, with OCO-2 having a small mean low bias against AMSR2 of −0.22 m/s, an RMSD of 0.75 m/s, and a correlation coefficient of 0.94. Although OCO-2 is restricted to clear-sky measurements, potential benefits of its higher spatial resolution relative to microwave instruments include the study of coastal wind processes, which may be able to inform certain economic sectors.

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Section: Discussionmentioning

confidence: 99%

Retrieved wind speed from the Orbiting Carbon Observatory-2

Nelson¹,

Eldering²,

Crisp³

et al. 2020

Preprint

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“…The CO2M mission is a proposed constellation of polar orbiting satellites with Equator crossing times around 11:30 local time (Sierk et al, 2019). The main payload will be an imaging spectrometer for retrieving CO 2 from measurements in the near-infrared and in two shortwave infrared spectral channels.…”

Section: Synthetic Satellite Observationsmentioning

confidence: 99%

“…Commission and the European Space Agency (ESA) are currently preparing the Copernicus Anthropogenic CO 2 Monitoring Mission (CO2M), a constellation of polar orbiting CO 2 satellites with imaging capability (Sierk et al, 2019). According to the current system concept, the satellites will carry additional instruments with supporting observations of NO 2 , aerosols and clouds.…”

Section: Introductionmentioning

confidence: 99%

Quantifying CO2 emissions of a city with the Copernicus Anthropogenic CO2 Monitoring satellite mission

Kuhlmann¹,

Brunner²,

Broquet³

et al. 2020

Preprint

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Abstract. We investigate the potential of the Copernicus Anthropogenic Carbon Dioxide (CO2) Monitoring (CO2M) mission, a proposed constellation of CO2 imaging satellites, to estimate the CO2 emissions of a city on the example of Berlin, the capital of Germany. On average, Berlin emits about 20 Mt CO2 yr−1 during satellite overpass (11:30 local time). The study uses synthetic satellite observations of a constellation of up to six satellites generated from one year of high-resolution atmospheric transport simulations. The emissions were estimated by (1) an analytical atmospheric inversion applied to the plume of Berlin simulated by the same model that was used to generate the synthetic observations, and (2) a mass-balance approach that estimates the CO2 flux through multiple cross-sections of the city plume detected by a plume detection algorithm. The plume was either detected from CO2 observations alone or from additional nitrogen dioxide (NO2) observations on the same platform. The two approaches span the range between the optimistic assumption of a perfect transport model that provides an accurate prediction of plume location and CO2 background, and the pessimistic assumption that plume location and background can only be determined reliably from the satellite observations. Often unfavorable meteorological conditions allowed to successfully apply the analytical inversion to only 11 out of 61 overpasses per satellite per year on average. From a single overpass, the instantaneous emissions of Berlin could be estimated with an average precision of 3.0 to 4.2 Mt yr−1 (15–21 % of emissions during overpass) depending on the assumed instrument noise ranging from 0.5 to 1.0 ppm. Applying the mass balance approach required the detection of a sufficiently large plume, which on average was only possible on 3 overpasses per satellite per year when using CO2 observations for plume detection. This number doubled to 6 estimates when the plumes were detected from NO2 observations due to the better signal-to-noise ratio and lower sensitivity to clouds of the measurements. Compared to the analytical inversion, the mass balance approach had a lower precision ranging from 8.1 to 10.7 Mt yr−1 (40–53 %), because it is affected by additional uncertainties introduced by the estimation of the location of the plume, the CO2 background field, and the wind speed within the plume. These uncertainties also resulted in systematic biases, especially without the NO2 observations. An additional source of bias were non-separable fluxes from outside of Berlin. Annual emissions were estimated by fitting a low-order periodic spline to the individual estimates to account for the temporal variability of the emissions. The analytical inversion was able to estimate annual emissions with an accuracy of 40 %)) when using the CO2 observations alone. When using the NO2 observations to detect the plume, the accuracy could be greatly improved to 22 % and 13 % with two and three satellites, respectively. Using the complementary information provided by the CO2 and NO2 observations on the CO2M mission, it should be possible to quantify annual emissions of a city like Berlin with an accuracy of about 10 to 20 %, even in the pessimistic case that plume location and CO2 background have to be determined from the observations alone. This requires, however, that the temporal coverage of the constellation is sufficiently high to resolve the temporal variability of emissions.

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“…A similar concept has been put forward by the CarbonSat mission (Bovensmann et al, 2010), which has evolved into a candidate for a future European carbon monitoring mission (e.g., Pillai et al, 2016;Broquet et al, 2018;Reuter et al, 2019). The CO2M mission currently under investigation at the European Space Agency aims at ground resolution of 4 km 2 (Sierk et al, 2019;Wu et al, 2019a). All these satellite missions and concepts rely on a multi-band spectral configuration that covers the oxygen (O 2 ) A-band at roughly 0.76 µm (NIR) and the CO 2 bands at 1.6 (SWIR-1) and 2.0 µm (SWIR-2).…”

Section: Introductionmentioning

confidence: 99%

“…For methane (CH 4 ), which poses similar remote sensing challenges as CO 2 , it has been demonstrated that a satellite spectrometer operating at coarse spectral resolution ( λ λ of a few hundred) on a single absorption band (around 2.35 µm) can achieve successful CH 4 hot-spot detection with a ground resolution of 30 m (Thompson et al, 2016). Similar results for CH 4 have been reported from aircraft sensors that reach ground pixel sizes on the order of 1-10 m (Dennison et al, 2013;Thorpe et al, 2016a, b;Krings et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Spectral sizing of a coarse-spectral-resolution satellite sensor for XCO2

et al. 2020

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Abstract. Verifying anthropogenic carbon dioxide (CO2) emissions globally is essential to inform about the progress of institutional efforts to mitigate anthropogenic climate forcing. To monitor localized emission sources, spectroscopic satellite sensors have been proposed that operate on the CO2 absorption bands in the shortwave-infrared (SWIR) spectral range with ground resolution as fine as a few tens of meters to about a hundred meters. When designing such sensors, fine ground resolution requires a trade-off towards coarse spectral resolution in order to achieve sufficient noise performance. Since fine ground resolution also implies limited ground coverage, such sensors are envisioned to fly in fleets of satellites, requiring low-cost and simple design, e.g., by restricting the spectrometer to a single spectral band. Here, we use measurements of the Greenhouse Gases Observing Satellite (GOSAT) to evaluate the spectral resolution and spectral band selection of a prospective satellite sensor with fine ground resolution. To this end, we degrade GOSAT SWIR spectra of the CO2 bands at 1.6 (SWIR-1) and 2.0 µm (SWIR-2) to coarse spectral resolution, without a further addition of noise, and we evaluate single-band retrievals of the column-averaged dry-air mole fractions of CO2 (XCO2) by comparison to ground truth provided by the Total Carbon Column Observing Network (TCCON) and by comparison to global “native” GOSAT retrievals with native spectral resolution and spectral band selection. Coarsening spectral resolution from GOSAT's native resolving power of >20 000 to the range of 700 to a few thousand makes the scatter of differences between the SWIR-1 and SWIR-2 retrievals and TCCON increase moderately. For resolving powers of 1200 (SWIR-1) and 1600 (SWIR-2), the scatter increases from 2.4 (native) to 3.0 ppm for SWIR-1 and 3.3 ppm for SWIR-2. Coarser spectral resolution yields only marginally worse performance than the native GOSAT configuration in terms of station-to-station variability and geophysical parameter correlations for the GOSAT–TCCON differences. Comparing the SWIR-1 and SWIR-2 configurations to native GOSAT retrievals on the global scale, however, reveals that the coarse-resolution SWIR-1 and SWIR-2 configurations suffer from some spurious correlations with geophysical parameters that characterize the light-scattering properties of the scene such as particle amount, size, height and surface albedo. Overall, the SWIR-1 and SWIR-2 configurations with resolving powers of 1200 and 1600 show promising performance for future sensor design in terms of random error sources while residual errors induced by light scattering along the light path need to be investigated further. Due to the stronger CO2 absorption bands in SWIR-2 than in SWIR-1, the former has the advantage that measurement noise propagates less into the retrieved XCO2 and that some retrieval information on particle scattering properties is accessible.

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The European CO2 Monitoring Mission: observing anthropogenic greenhouse gas emissions from space

Cited by 48 publications

References 16 publications

Retrieved wind speed from the Orbiting Carbon Observatory-2

Retrieved wind speed from the Orbiting Carbon Observatory-2

Quantifying CO<sub>2</sub> emissions of a city with the Copernicus Anthropogenic CO<sub>2</sub> Monitoring satellite mission

Spectral sizing of a coarse-spectral-resolution satellite sensor for XCO<sub>2</sub>

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The European CO2 Monitoring Mission: observing anthropogenic greenhouse gas emissions from space

Cited by 48 publications

References 16 publications

Retrieved wind speed from the Orbiting Carbon Observatory-2

Retrieved wind speed from the Orbiting Carbon Observatory-2

Quantifying CO&lt;sub&gt;2&lt;/sub&gt; emissions of a city with the Copernicus Anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; Monitoring satellite mission

Spectral sizing of a coarse-spectral-resolution satellite sensor for XCO&lt;sub&gt;2&lt;/sub&gt;

Contact Info

Product

Resources

About

Quantifying CO<sub>2</sub> emissions of a city with the Copernicus Anthropogenic CO<sub>2</sub> Monitoring satellite mission

Spectral sizing of a coarse-spectral-resolution satellite sensor for XCO<sub>2</sub>