Versatile and Targeted Validation of Space-Borne XCO2, XCH4 and XCO Observations by Mobile Ground-Based Direct-Sun Spectrometers

Satellite measurements of the atmospheric concentrations of carbon dioxide (CO2), methane (CH4) and carbon monoxide (CO) require careful validation. In particular for the greenhouse gases CO2 and CH4, concentration gradients are minute challenging the ultimate goal to quantify and monitor anthropogenic emissions and natural surface-atmosphere fluxes. The upcoming European Copernicus Carbon Monitoring mission (CO2M) will focus on anthropogenic CO2 emissions, but it will also be able to measure CH4. There are other missions such as the Sentinel-5 Precursor and the Sentinel-5 series that target CO which helps attribute the CO2 and CH4 variations to specific processes. Here, we review the capabilities and use cases of a mobile ground-based sun-viewing spectrometer of the type EM27/SUN. We showcase the performance of the mobile system for measuring the column-average dry-air mole fractions of CO2 (XCO2), CH4 (XCH4) and CO (XCO) during a recent deployment (Feb./Mar. 2021) in the vicinity of Japan on research vessel Mirai which adds to our previous campaigns on ships and road vehicles. The mobile EM27/SUN has the potential to contribute to the validation of 1) continental-scale background gradients along major ship routes on the open ocean, 2) regional-scale gradients due to continental outflow across the coast line, 3) urban or other localized emissions as mobile part of a regional network and 4) emissions from point sources. Thus, operationalizing the mobile EM27/SUN along these use cases can be a valuable asset to the validation activities for CO2M, in particular, and for various upcoming satellite missions in general.

Evaporation in Hydrological Models Under Rising CO2: A Jump into The Unknown

Many hydrological models use the concept of potential evaporation (PE) to simulate actual evaporation. PE formulations often neglect the effect of carbon dioxide (CO2), which challenges their relevance in a context of climate change and rapid changes in CO2 atmospheric concentrations. In this work, we implement three options from the literature to take into account the effect of CO2 on stomatal resistance in the well-known Penman–Monteith PE formulation. We assess their impact on future runoff using the Budyko framework over France. On the basis of an ensemble of Euro-Cordex climate projections using the RCP 4.5 and RCP 8.5 scenarios, we show that taking into account CO2 in PE formulations largely reduces PE values but also limits projections of runoff decrease, especially under an emissive scenario, namely, the RCP 8.5. Whereas the classic Penman–Monteith formulation yields decreasing runoff projections over most of France, taking into account CO2 yields more contrasting results. Runoff increase becomes likely in the north of France, which is an energy-limited area, with different levels of runoff response produced by the three tested formulations. The results highlight the sensitivity of hydrological projections to the processes represented in the PE formulation.

Volcanic Gas Hazard Assessment in the Baia di Levante Area (Vulcano Island, Italy) Inferred by Geochemical Investigation of Passive Fluid Degassing

In a volcanic area, the composition of air is influenced by the interaction between fluids generated from many different environments (magmatic, hydrothermal, meteoric, and marine). Any physical and chemical variation in one of these subsystems is able to modify the outgassing dynamic. The increase of natural gas hazard, related to the presence of unhealthy components in air, may depend on temporary changes both in the pressure and chemical gradients that generate transient fluxes of gases and can have many different causes. Sometimes, the content of unhealthy gases approaches unexpected limits, without clear warning. In this case, an altered composition of the air can be only revealed after accurate sampling procedures and laboratory analysis. The investigations presented here are a starting point to response to the demand for a new monitoring program in the touristic area of Baia di Levante at Vulcano Island (Aeolian archipelago, Italy). Three multiparametric geochemical surveys were carried in the touristic area of Baia di Levante at Vulcano Island (Aeolian archipelago, Italy) in 2011, 2014, and 2015. Carbon dioxide (CO2) and hydrogen sulfide (H2S) are the main undesired components, usually present at the local scale. Anomalous CO2 and H2S outputs from soil and submarine bubbling vents were identified; the thermal anomaly of the ground was mapped; atmospheric concentrations of CO2 and H2S were measured in the air 30 cm above the ground surface. Atmospheric concentrations above the suggested limits for the wellbeing of human health were retrieved in open areas where tourists stay and where CO2 can accumulate under absence of wind.

Potensi Reduksi Emisi GRK dan Kelayakan Finansial dari Teknologi Hidrotermal untuk Pengolahan Sampah di Kabupaten Tangerang

Peningkatan konsentrasi gas rumah kaca (GRK) di atmosfer telah menimbulkan efek pemanasan global. Salah satu kontributor emisi GRK adalah penumpukan sampah di TPA tanpa pengolahan lebih lanjut. TPA Jatiwaringin di Kabupaten Tangerang diprediksi akan mengalami overcapacity, sehingga diperlukan mitigasi untuk mengurangi sampah di TPA, salah satunya dengan teknologi hidrotermal. Namun dalam penerapan teknologi hidrotermal membutuhkan biaya yang tinggi. Penelitian ini bertujuan untuk mengestimasi potensi emisi GRK sebelum adanya proyek hidrotermal, mengestimasi potensi reduksi emisi GRK setelah adanya proyek hidrotermal, menganalisis kelayakan finansial dari proyek hidrotermal. Penelitian ini menggunakan metode Clean Development Mechanism (CDM) AMS-III.E untuk mengestimasi potensi reduksi emisi GRK proyek hidrotermal dan analisis cashflow untuk mengevaluasi kelayakan finansialnya. Hasil penelitian ini menunjukkan emisi baseline pada tahun 2021 diestimasi sebesar 18.766 t CO2 e dan akan meningkat menjadi 21.865 t CO2 e (16,5%) pada tahun 2030. Emisi proyek diestimasi sebesar 5883 t CO2 e per tahun. Rata-rata persentase potensi reduksi emisi GRK dari proyek hidrotermal tahun 2021-2030 sebesar 70,94% (Skenario 2 putaran per hari) dan 68,26% (Skenario 3 putaran per hari). Proyek hidrotermal juga layak secara finansial, dengan syarat produk hidrotermal yaitu Refused Derived Fuel (RDF) dapat terjual setidaknya 72% dan jumlah iuran masyarakat yang terkumpul minimal 50% dari target penerimaan iuran. ABSTRACTAn increase in the atmospheric concentrations of greenhouse gases (GHGs) produces global warming effect. One of GHGs emissions contributors is waste accumulation of in the landfill. Jatiwaringin landfill in Tangerang Regency is predicted to reach overcapacity. Therefore, mitigation measures are required to reduce such waste. One of potential measures is hydrothermal treatment technology for urban scale, but its implementation is costly. This study aims to: estimate the potential GHGs emissions prior the hydrothermal project, estimate the potential GHGs emission reduction after the project, and analyze the financial feasibility of the project. This study employs Clean Development Mechanism (CDM) method i.e., AMS-III.E to estimate the GHGs emissions reduction potential of hydrothermal projects and cashflow analysis to evaluate the project financial feasibility. The results show that the baseline emissions in 2021 are estimated at 18,766 t CO2 e and would increase to 21,865 t CO2 e (16.5%) in 2030. The potential project emissions are estimated at 5883 t CO2 e per year. The GHGs emission reductions could reach 70.94% (2 batches per day) and 68.26% (3 batches per day) within 2021-2030. Furthermore, the hydrothermal project would be financially feasible, if the hydrothermal product i.e., Refused Derived Fuel (RDF) are sold at least 72% and the cumulative households-contribution is at least 50% of the target.

The Space CARBon Observatory (SCARBO) concept: Assessment of XCO₂ and XCH₄ retrieval performance

Several single-platform satellite missions have been designed during the past decades in order to retrieve the atmospheric concentrations of anthropogenic greenhouse gases (GHG), initiating worldwide efforts towards better monitoring of their sources and sinks. To set up a future operational system for anthropogenic GHG emission monitoring, both revisit frequency and spatial resolution need to be improved. The Space CARBon Observatory (SCARBO) project aims at significantly increasing the revisit frequency of spaceborne GHG measurements, while reaching state-of-the-art precision requirements, by implementing a concept of small satellite constellation. It would accommodate a miniaturized GHG sensor named NanoCarb coupled with an aerosol instrument, the multi-angle polarimeter SPEXone. More specifically, the NanoCarb sensor is a static Fabry-Perot imaging interferometer with a 2.3 × 2.3 km2 spatial resolution and 200 km swath. It samples a truncated interferogram at optical path differences (OPDs) optimally sensitive to all the geophysical parameters necessary to retrieve column-averaged dry-air mole fractions of CO2 and CH4 (hereafter XCO2 and XCH4). In this work, we present the Level 2 performance assessment of the concept proposed in the SCARBO project. We perform inverse radiative transfer to retrieve XCO2 and XCH4 directly from synthetic NanoCarb truncated interferograms, and provide their systematic and random errors, column vertical sensitivities and degrees of freedom as a function of five scattering error-critical atmospheric and observational parameters. We show that NanoCarb XCO2 and XCH4 systematic retrieval errors can be greatly reduced with SPEXone posterior outputs used as improved prior aerosol constraints. For two thirds of the soundings, located at the centre of the 200 km NanoCarb swath, XCO2 and XCH4 random errors span 0.5–1 ppm and 4–6 ppb, respectively, compliant with their respective 1-ppm and 6-ppb precision objectives. Finally, these Level 2 performance results are parameterized as a function of the explored scattering error-critical atmospheric and observational parameters in order to time-efficiently compute extensive L2 error maps for future CO2 and CH4 flux estimation performance studies.

The CO2 Human Emissions (CHE) Project: First Steps Towards a European Operational Capacity to Monitor Anthropogenic CO2 Emissions

The Paris Agreement of the United Nations Framework Convention on Climate Change is a binding international treaty signed by 196 nations to limit their greenhouse gas emissions through ever-reducing Nationally Determined Contributions and a system of 5-yearly Global Stocktakes in an Enhanced Transparency Framework. To support this process, the European Commission initiated the design and development of a new Copernicus service element that will use Earth observations mainly to monitor anthropogenic carbon dioxide (CO2) emissions. The CO2 Human Emissions (CHE) project has been successfully coordinating efforts of its 22 consortium partners, to advance the development of a European CO2 monitoring and verification support (CO2MVS) capacity for anthropogenic CO2 emissions. Several project achievements are presented and discussed here as examples. The CHE project has developed an enhanced capability to produce global, regional and local CO2 simulations, with a focus on the representation of anthropogenic sources. The project has achieved advances towards a CO2 global inversion capability at high resolution to connect atmospheric concentrations to surface emissions. CHE has also demonstrated the use of Earth observations (satellite and ground-based) as well as proxy data for human activity to constrain uncertainties and to enhance the timeliness of CO2 monitoring. High-resolution global simulations (at 9 km) covering the whole of 2015 (labelled CHE nature runs) fed regional and local simulations over Europe (at 5 km and 1 km resolution) and supported the generation of synthetic satellite observations simulating the contribution of a future dedicated Copernicus CO2 Monitoring Mission (CO2M).