Greenhouse Gas Measurements Research Articles

Applying the internet of things (IoT) for raising black soldier Fly (BSF) in closed system to minimize greenhouse gas emissions

The Black Soldier Fly (BSF), scientifically known as Hermetia Illucens L., effectively reduces organic waste and decreases harmful gas emissions more efficiently than landfill or composting methods. However, it can still produce harmful gases during the rearing of BSF larvae, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ammonia (NH3), which contribute directly and indirectly to the greenhouse effect. The pH level of the food provided to the larvae affects their biomass and leads to varying levels of gas emissions. This study aims to investigate the impact of greenhouse gas emissions when different pH levels of food are used, utilizing IoT technology to measure greenhouse gases and control the environmental conditions for rearing BSF larvae. The greenhouse gases monitored in this study include carbon dioxide (CO2) and methane (CH4), with environmental factors such as air temperature, humidity, soil moisture, and light intensity being controlled. The experiment tested pH levels ranging from 2.0, 4.0, 6.0, 7.0, and 8.0 to 10.0. The results show that different pH levels in food affect the emission of CO2 and CH4. Initially, a large amount of CO2 is released, gradually decreasing over time, while CH4 emissions steadily increase. In the early days, CH4 emissions are unstable, fluctuating before stabilizing. Food with a pH of 2.0 results in the lowest average CO2 emissions (430.53 PPM) from BSF larvae, and the lowest CH4 emissions (16.11 PPM) are also observed with a pH of 2.0.

Spectral Calibration of the Spectrometer on Board the Colombian FACSAT-2 Satellite Mission

This paper presents the results of the integration, commissioning, and in-orbit calibration of the ARGUS 2000 SWIR wavelength spectrometer onboard the Colombian FACSAT-2 satellite, Colombia’s first satellite used for the measurement of greenhouse gases (GHG). The satellite has been in orbit for approximately one year, gathering spectral signatures in order to characterize the data and perform calibration. The calibration represents a certain behavior following a second-order adjustment. For data analysis, retrieval algorithms have been developed to obtain synthetic spectra using the Genspect 1.2 software code. These synthetic spectra were obtained from the spectroscopic data associated with atmospheric gases (H2O, O2, CO, and CO2), which are stored in the HITRAN database. Attempting to achieve a more accurate simulation of the experimental spectrum, certain instrumental parameters have been incorporated into the synthetic spectrum, including the resolution of the spectrometer, the field of view (FOV) angle of observation, the limited quantum efficiency of detection, and the slit function. As a result, six slit functions were tested, with the Gaussian and the diffraction functions proving to be the most effective. Finally, a profile of Total Carbon Column Observing Network (TCCON) concentrations was used for comparison with a spectral signature acquired by FACSAT-2, resulting in a close match between the synthetic spectrum and the measured spectrum.

Permafrost Region Greenhouse Gas Budgets Suggest a Weak CO2 Sink and CH4 and N2O Sources, But Magnitudes Differ Between Top‐Down and Bottom‐Up Methods

AbstractLarge stocks of soil carbon (C) and nitrogen (N) in northern permafrost soils are vulnerable to remobilization under climate change. However, there are large uncertainties in present‐day greenhouse gas (GHG) budgets. We compare bottom‐up (data‐driven upscaling and process‐based models) and top‐down (atmospheric inversion models) budgets of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) as well as lateral fluxes of C and N across the region over 2000–2020. Bottom‐up approaches estimate higher land‐to‐atmosphere fluxes for all GHGs. Both bottom‐up and top‐down approaches show a sink of CO2 in natural ecosystems (bottom‐up: −29 (−709, 455), top‐down: −587 (−862, −312) Tg CO2‐C yr−1) and sources of CH4 (bottom‐up: 38 (22, 53), top‐down: 15 (11, 18) Tg CH4‐C yr−1) and N2O (bottom‐up: 0.7 (0.1, 1.3), top‐down: 0.09 (−0.19, 0.37) Tg N2O‐N yr−1). The combined global warming potential of all three gases (GWP‐100) cannot be distinguished from neutral. Over shorter timescales (GWP‐20), the region is a net GHG source because CH4 dominates the total forcing. The net CO2 sink in Boreal forests and wetlands is largely offset by fires and inland water CO2 emissions as well as CH4 emissions from wetlands and inland waters, with a smaller contribution from N2O emissions. Priorities for future research include the representation of inland waters in process‐based models and the compilation of process‐model ensembles for CH4 and N2O. Discrepancies between bottom‐up and top‐down methods call for analyses of how prior flux ensembles impact inversion budgets, more and well‐distributed in situ GHG measurements and improved resolution in upscaling techniques.

Advancing CubeSats Capabilities: Ground-Based Calibration of Uvsq-Sat NG Satellite’s NIR Spectrometer and Determination of the Extraterrestrial Solar Spectrum

Uvsq-Sat NG is a French 6U CubeSat (10 × 20 × 30 cm) of the International Satellite Program in Research and Education (INSPIRE) designed primarily for observing greenhouse gases (GHG) such as CO2 and CH4, measuring the Earth’s radiation budget (ERB), and monitoring solar spectral irradiance (SSI) at the top-of-atmosphere (TOA). It epitomizes an advancement in CubeSat technology, showcasing its enhanced capabilities for comprehensive Earth observation. Scheduled for launch in 2025, the satellite carries a compact and miniaturized near-infrared (NIR) spectrometer capable of performing observations in both nadir and solar directions within the wavelength range of 1100 to 2000 nm, with a spectral resolution of 7 nm and a 0.15° field of view. This study outlines the preflight calibration process of the Uvsq-Sat NG NIR spectrometer (UNIS), with a focus on the spectral response function and the absolute calibration of the instrument. The absolute scale of the UNIS spectrometer was accurately calibrated with a quartz-halogen lamp featuring a coiled-coil tungsten filament, certified by the National Institute of Standards and Technology (NIST) as a standard of spectral irradiance. Furthermore, this study details the ground-based measurements of direct SSI through atmospheric NIR windows conducted with the UNIS spectrometer. The measurements were obtained at the Pommier site (45.54°N, 0.83°W) in Charentes–Maritimes (France) on 9 May 2024. The objective of these measurements was to verify the absolute calibration of the UNIS spectrometer conducted in the laboratory and to provide an extraterrestrial solar spectrum using the Langley-plot technique. By extrapolating the data to AirMass Zero (AM0), we obtained high-precision results that show excellent agreement with SOLAR-HRS and TSIS-1 HSRS solar spectra. At 1.6 μm, the SSI was determined to be 238.59 ± 3.39 mW.m−2.nm−1 (k = 2). These results demonstrate the accuracy and reliability of the UNIS spectrometer for both SSI observations and GHG measurements, providing a solid foundation for future orbital data collection and analysis.

Fiducial Reference Measurement for Greenhouse Gases (FRM4GHG)

The Total Carbon Column Observing Network (TCCON) and the Infrared Working Group of the Network for the Detection of Atmospheric Composition Change (NDACC-IRWG) are two ground-based networks that provide the retrieved concentrations of up to 30 atmospheric trace gases, using solar absorption spectrometry. Both networks provide reference measurements for the validation of satellites and models. TCCON concentrates on long-lived greenhouse gases (GHGs) for carbon cycle studies and validation. The number of sites is limited, and the geographical coverage is uneven, covering mainly Europe and the USA. A better distribution of stations is desired to improve the representativeness of the data for various atmospheric conditions and surface conditions and to cover a large latitudinal distribution. The two successive Fiducial Reference Measurements for Greenhouse Gases European Space Agency projects (FRM4GHG and FRM4GHG2) aim at the assessment of several low-cost portable instruments for precise measurements of GHGs to complement the existing ground-based sites. Several types of low spectral resolution Fourier transform infrared (FTIR) spectrometers manufactured by Bruker, namely an EM27/SUN, a Vertex70, a fiber-coupled IRCube, and a Laser Heterodyne spectro-Radiometer (LHR) developed by UK Rutherford Appleton Laboratory are the participating instruments to achieve the Fiducial Reference Measurements (FRMs) status. Intensive side-by-side measurements were performed using all four instruments next to the Bruker IFS 125HR high spectral resolution FTIR, performing measurements in the NIR (TCCON configuration) and MIR (NDACC configuration) spectral range. The remote sensing measurements were complemented by AirCore launches, which provided in situ vertical profiles of target gases traceable to the World Meteorological Organization (WMO) reference scale. The results of the intercomparisons are shown and discussed. Except for the EM27/SUN, all other instruments, including the reference TCCON spectrometer, needed modifications during the campaign period. The EM27/SUN and the Vertex70 provided stable and precise measurements of the target gases during the campaign with quantified small biases. As part of the FRM4GHG project, one EM27/SUN is now used as a travel standard for the verification of column-integrated GHG measurements. The extension of the Vertex70 to the MIR provides the opportunity to retrieve additional concentrations of N2O, CH4, HCHO, and OCS. These MIR data products are comparable to the retrieval results from the high-resolution IFS 125HR spectrometer as operated by the NDACC. Our studies show the potential for such types of spectrometers to be used as a travel standard for the MIR species. An enclosure system with a compact solar tracker and meteorological station has been developed to house the low spectral resolution portable FTIR systems for performing solar absorption measurements. This helps the spectrometers to be mobile and enables autonomous operation, which will help to complement the TCCON and NDACC networks by extending the observational capabilities at new sites for the observation of GHGs and additional air quality gases. The development of the retrieval software allows comparable processing of the Vertex70 type of spectra as the EM27/SUN ones, therefore bringing them under the umbrella of the COllaborative Carbon Column Observing Network (COCCON). A self-assessment following the CEOS-FRM Maturity Matrix shows that the COCCON is able to provide GHG data products of FRM quality and can be used for either short-term campaigns or long-term measurements to complement the high-resolution FTIR networks.

PSLBII-6 Measuring greenhouse gas emissions from biogas facility as manure treatment and comparing with 2006 IPCC guideline calculation

Abstract To achieve global net-zero emission goals by 2050, Korea government announced 2050 carbon neutral scenarios. Substitution of fossil fuel power plants to renewable energy plants is the main strategic long-term vision. It included increasing the number of a biogas facility to retrieve methane (CH₄) for energy sources from manure. As increasing the biogas facility with using manure, it is important to quantify and monitor the greenhouse gas (GHG) such as CH₄ and nitrous oxide (N₂O). The objective of this research was to measure the GHG emissions from the biogas facility as the baseline to construct the country-specific emission factors, and to compare the emissions between site measured data and 2006 IPCC guideline (2006 IPCC GL). This facility was constituted with feedstock, anaerobic digestion, biogas storage, and liquid fertilizer storage. The facility treats 70 tons of swine manure from 20,000 pigs and 30 ton of food waste per day and generates 3,000 m3 /d of biogas. All gases were vented by negative pressure from the odor treatment tower, except the generator and its blowers. Quantification of the total GHG emissions from the biogas facility was conducted for 24 h every 2 wk, from July 2022 to October 2023, using CH₄/N2O Analyzer (Los Gatos Research, San Jose, CA). The total emissions of CH₄ and N2O were 12,545 ± 2,297 kgCH4/yr and 442 ± 1,123 kg N2O/yr. To compare total GHG emissions from the facility, it was changed by carbon dioxide (CO2) equivalent. The results showed that when the system of biogas facility operated normally, it can reduce the total GHG emissions by up to 60% compared with 2006 IPCC GL calculation. However, if the system does not circulate properly, it can result in 18 times greater emissions due to N2O, leading to significant increase in GHG emissions. To reduce GHG from biogas facilities, it is crucial to ensure continuous operation of organic matter in and out, and increase the amount of sufficient aeration in liquid fertilizer storage.

265 Factors influencing greenhouse gas measurements in beef cattle: Understanding GreenFeed results

Abstract The environmental impact of the livestock industry, particularly concerning greenhouse gas (GHG) emissions, has become a growing concern. Addressing this challenge requires accurate and efficient measurement methods for monitoring and mitigating gas emissions. One noteworthy method is the GreenFeed (GF), developed by C-Lock Inc., designed to measure methane (CH4) emissions and carbon dioxide (CO2) concentrations in ruminants through a real-time non-invasive monitoring device with reduced labor intensity and a high level of precision. The GF is the most used equipment to measure GHG in cattle; however, there is still considerable variability that is not explained due to the variation among animals. Thus, the objective of this work is to analyze other environmental factors influencing GF measurements in cattle to explain the variability observed. For this, a total of 127 yearling Angus steers were evaluated for GHG emissions through 6 GF units placed in 6 different pastures (n = 21 to 22 animals/pasture). Animals were evaluated from June to August (2023) at the South Dakota State University Cottonwood Field Station (Cottonwood, SD). The mean values of GHG evaluated were 174g CH4/d and 5,885 g CO2/d, showing a coefficient of variation (CV%) of 41% and 27%, respectively. To evaluate GHG variation, we used ANOVA type III (package car in R) for the following variables measured by the GF: temperature, wind speed, wind direction, variance influenced by the GF unit by itself, and animal factors as the number of visits and the duration per visit. Table 1 shows the percentage of variance explained by all these factors on the variation of CH4 and CO2; between-animal variation (13 and 15.5%), the GF unit (7.2 and 6.3%), duration of visits (2.7 and 2.8%), wind speed (1.7 and 1.3%), temperature (1.3 and 0.0%), wind direction (0.1 and 0.1%) and number of visits (0.3 and 0.0%). The residual error of the model represented 73.7% for CH4 and 73.9% for CO2, indicating the vast percentage of non-explained variance in these two gases, which, in this case, could be associated with different grazing systems or stocking density of animals in the different pastures. Results of this study demonstrate how other factors, non-related to the animal or the type of feed, may contribute to explaining the variation observed in CH4 and CO2 emissions. In future experiments, these factors should be considered to improve the accuracy of measurements and establish smaller differences between groups/individuals.

Sustainable city tourism—A systematic analysis of Budapest and Mumbai

International Tourist arrivals, guest nights and their contribution to GDP are key indicators reflecting a country’s actual perception. A growing percentage of tourists prioritize environmental awareness across tourism products and services each year. Destinations aiming to meet the expectations of eco conscious travellers must center sustainability in their branding strategies. This approach aligns with UNWTO (World Tourism Organization of United Nations) Agenda 2030 of sustainable tourism development. This paper examines various dimensions of sustainability in tourism, focusing on Mumbai and Budapest. Using specific sustainability indicators, it employs sustainability city index to compare international tourism in these cities, which face distinct environmental and infrastructural challenges. By using specific sustainability indicators such as: (1) Carbon Emissions: Measurement of the total greenhouse gases produced by the city. (2) Proportion of Green Public Spaces: Evaluation of the percentage of urban areas dedicated to parks and natural spaces. (3) State of Infrastructure: Assessment of the quality and sustainability of urban infrastructure, including transportation systems. (4) Water Usage: Analysis of the amount of water consumed by the city and its conservation practices. (5) Waste Management: Review of the city’s effectiveness in managing and recycling waste. (6) Air Pollution: Monitoring of the levels of pollutants in the air to assess environmental health. This research provides a comprehensive view of how cities can attract environmentally conscious tourists. The findings offer guidance for policy makers and tourism professionals to align strategies with sustainable development goals. This detailed assessment highlights each city’s commitment to sustainability and delivers actionable insights for improving tourism strategies in accordance with global standards. While valuable for tourism professionals, it is important to note that this research covers only six SCI factors, with incomplete data for studied countries. The practical and social implications indicate areas needing improvement to enhance tourist appeal, beneficial for industry professionals and educational purposes. This comparative analysis aids in promoting sustainable tourism and can guide governments in achieving sustainability goals with raising awareness of environmental quality and conscious living.

Greenhouse Gas Emissions from a 20-Year-Old Restored Peatland

Peatlands are ecosystems with unique hydrological and ecological properties that serve as critical carbon reservoirs, helping facilitate the reduction of greenhouse gases (GHG). In Canada, the peat industry uses vacuum harvesting to extract peat for horticultural use. This disturbs the natural ecosystem, increasing CO2 and decreasing CH4 emissions due to complete removal of surface vegetation and lowering of the water table. Following years of extraction, if these peatlands are not properly restored, GHG emissions will increase, negatively impacting the climate. The moss layer transfer technique (MLTT) is the primary method for restoring peatlands in Canada. The MLTT allows peatlands to regain their natural ecosystem function and to reaccumulate peat. This is done by revegetation of key species including sphagnum moss, and rewetting of the peatland through the blockage of drainage ditches. My research project investigates a peatland in Pointe-Lebel, Quebec restored in 2004 using MLTT following vacuum extraction. I used the closed chamber method to measure the CO2 and CH4 exchanges at the plant community scale and three repetitions of each of moss, shrubs, and cotton grass communities were followed throughout the summer. Wells at each collar provided the water table depth; a controlling variable for GHG fluxes. I conducted a vegetation survey at peak plant productivity to characterize the proportions of the plant communities and to allow chamber measurements of GHG to be scaled by the contribution of each plant community. If successful, a restored peatland will be a net sink of carbon. Preliminary data analysis at this 20-year-old restored site indicates a net CO2 sink during the summer of 2024. My data also suggests that the site is a small source of CH4. The results from my project will aid in advancing research on peatlands, stressing the importance of taking the proper steps towards restoration.

Riparian vegetation influences aquatic greenhouse gas production in an agricultural landscape

Although riparian vegetation is widely acknowledged for its positive impact on soil and water quality and its role in regulating terrestrial greenhouse gas emissions in agricultural landscapes, there remains a gap in understanding how different types of riparian vegetation affect aquatic greenhouse gas production. Thus, the objective of this study was to investigate whether the type of vegetation within riparian zones influenced aquatic environmental factors, subsequently impacting aquatic greenhouse gas emissions. To address this, we measured greenhouse gases in the aquatic environment bordered by riparian zones with herbaceous vegetation (GRS) compared to undisturbed natural riparian forests dominated by deciduous (UNF-D) or coniferous (UNF-C) vegetation or a rehabilitated riparian forest (RH). Our findings indicate that aquatic CO2 concentrations were not influenced (p < 0.05) by vegetation type ranging from 9 g L−1 to 11 g L−1. In contrast, aquatic CH4 concentrations were significantly lower (p < 0.05) in treed riparian zones, ranging from 14 μg L−1 to 24 μg L−1, compared to a riparian zone with herbaceous vegetation (34 μg L−1). However, we observed significantly higher (p < 0.05) aquatic N2O concentrations in treed riparian zones (9.5 μg L−1 to 10.3 μg L−1), particularly those dominated by coniferous vegetation (23.0 μg L−1), compared to the riparian zone with herbaceous vegetation (7.7 μg L−1). The total CO2-C equivalent (i.e., CO2 + CH4 + N2O) was highest in the riparian zone with coniferous trees (UNF-C: 10,717 mg CO2-Ceq L−1), followed by the GRS (9494 mg CO2-Ceq L−1), RH (9423 mg CO2-Ceq L−1) and UNF-D (9,183 mg CO2-Ceq L−1) riparian zone. Moreover, riparian vegetation was influenced by various environmental factors that likely controlled physicochemical and biological processes related to the production of greenhouse gases within the aquatic environment.

Measuring Dissolved Methane in Aquatic Ecosystems Using An Optical Spectroscopy Gas Analyzer.

Measuring greenhouse gas (GHG) fluxes and pools in ecosystems are becoming increasingly common in ecological studies due to their relevance to climate change. With it, the need for analytical platforms adaptable to measuring different pools and fluxes within research groups also grows. This study aims to develop a procedure to use portable optical spectroscopy-based gas analyzers, originally designed and marketed for gas flux measurements, to measure GHG concentrations in aqueous samples. The protocol involves the traditional headspace equilibration technique followed by the injection of a headspace gas subsample into a chamber connected through a closed loop to the inlet and outlet ports of the gas analyzer. The chamber is fabricated from a generic mason jar and simple laboratory supplies, and it is an ideal solution for samples that may require pre-injection dilution. Methane concentrations measured with the chamber are tightly correlated (r2 > 0.98) with concentrations determined separately through gas chromatography-flame ionization detection (GC-FID) on subsamples from the same vials. The procedure is particularly relevant for field studies in remote areas where chromatography equipment and supplies are not readily available, offering a practical, cheaper, and more efficient solution for measuring methane and other dissolved greenhouse gas concentrations in aquatic systems.

Permaculture Management of Arable Soil Increases Soil Microbial Abundance, Nutrients, and Carbon Stocks Compared to Conventional Agriculture

Conventional agricultural practices severely deplete the soil of essential organic matter and nutrients, increasing its vulnerability to disease, drought, and flooding. Permaculture is a form of agroecology adopting a whole ecosystem approach to create a set of principles and design frameworks for enriching soil fertility, but there is little scientific evidence of its efficiency. This study compares two permaculture managed sites with a conventional arable site to investigate the effect of permaculture management on soil fertility. We used phospholipid fatty acid analysis to estimate microbial abundance and diversity and related these to measured soil nutrients and carbon stocks. The potential of permaculture management to mitigate soil greenhouse gas emissions was assessed during a laboratory soil incubation and measurement of greenhouse gases via gas chromatography. Overall, the permaculture managed allotments had three times higher microbial biomass, one and a half times higher nitrogen, and four times higher carbon content than the arable site. Permaculture soils had larger carbon dioxide and nitrous oxide fluxes compared to arable soil, but all sites had a mean negative flux in methane. Permaculture management by use of organic amendments and no-dig practices provides a constant slow release of nutrients and build-up of organic matter and carbon and consequently promotes greater bacterial and fungal biomass within the soil.

Impact of three decades of warming, increased nutrient availability, and increased cloudiness on the fluxes of greenhouse gases and biogenic volatile organic compounds in a subarctic tundra heath.

Climate change is exposing subarctic ecosystems to higher temperatures, increased nutrient availability, and increasing cloud cover. In this study, we assessed how these factors affect the fluxes of greenhouse gases (GHGs) (i.e., methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2)), and biogenic volatile organic compounds (BVOCs) in a subarctic mesic heath subjected to 34 years of climate change related manipulations of temperature, nutrient availability, and light. GHGs were sampled from static chambers and gases analyzed with gas chromatograph. BVOCs were measured using the push-pull method and gases analyzed with chromatography-mass spectrometry. The soil temperature and moisture content in the warmed and shaded plots did not differ significantly from that in the controls during GHG and BVOC measurements. Also, the enclosure temperatures during BVOC measurements in the warmed and shaded plots did not differ significantly from temperatures in the controls. Hence, this allowed for assessment of long-term effects of the climate treatment manipulations without interference of temperature and moisture differences at the time of measurements. Warming enhanced CH4 uptake and the emissions of CO2, N2O, and isoprene. Increased nutrient availability increased the emissions of CO2 and N2O but caused no significant changes in the fluxes of CH4 and BVOCs. Shading (simulating increased cloudiness) enhanced CH4 uptake but caused no significant changes in the fluxes of other gases compared to the controls. The results show that climate warming and increased cloudiness will enhance CH4 sink strength of subarctic mesic heath ecosystems, providing negative climate feedback, while climate warming and enhanced nutrient availability will provide positive climate feedback through increased emissions of CO2 and N2O. Climate warming will also indirectly, through vegetation changes, increase the amount of carbon lost as isoprene from subarctic ecosystems.

Marine aquaculture can deliver 40% lower carbon footprints than freshwater aquaculture based on feed, energy and biogeochemical cycles.

Freshwater aquaculture is an increasingly important source of blue foods but produces substantial methane and nitrous oxide emissions. Marine aquaculture, also known as mariculture, is a smaller sector with a large growth potential, but its climate impacts are challenging to accurately quantify. Here we assess the greenhouse gas emissions from mariculture's aquatic environment in global potentially suitable areas at 10 km resolution on the basis of marine biogeochemical cycles, greenhouse gas measurements from research cruises and satellite-observed net primary productivity. Mariculture's aquatic emissions intensities are estimated to be 1-6 g CH4 kg-1 carcass weight and 0.05-0.2 g N2O kg-1 carcass weight, >98% and >80% lower than freshwater systems. Using a life-cycle assessment approach, we show that mariculture's carbon footprints are ~40% lower than those of freshwater aquaculture based on feed, energy use and the aquatic environment emissions. Adoption of mariculture alongside freshwater aquaculture production could offer considerable climate benefits to meet future dietary protein and nutritional needs.

DivyaSat: Green Horizon Explorer

The "DivyaSat" project aims to tackle climate change and global warming by employing miniature, cost-effective instruments on a CubeSat platform. Inspired by the success of MeznSat, DivyaSat plans to utilize a shortwave infrared (SWIR) micro-spectrometer, called Argus 2000, to measure greenhouse gas concentrations in the atmosphere. Alongside the SWIR spectrometer, DivyaSat will incorporate a high-definition camera for accurate geolocation. This combination of instruments positions DivyaSat as a unique CubeSat mission capable of generating valuable data for atmospheric correction algorithms. This abstract provides an overview of DivyaSat's mission objectives, design, and potential contributions to understanding greenhouse gas concentrations in the atmosphere.

Underestimation of Thermogenic Methane Emissions in New York City.

Recent studies have shown that methane emissions are underestimated by inventories in many US urban areas. This has important implications for climate change mitigation policy at the city, state, and national levels. Uncertainty in both the spatial distribution and sectoral allocation of urban emissions can limit the ability of policy makers to develop appropriately focused emission reduction strategies. Top-down emission estimates based on atmospheric greenhouse gas measurements can help to improve inventories and inform policy decisions. This study presents a new high-resolution (0.02 × 0.02°) methane emission inventory for New York City and its surrounding area, constructed using the latest activity data, emission factors, and spatial proxies. The new high-resolution inventory estimates of methane emissions for the New York-Newark urban area are 1.3 times larger than those for the gridded Environmental Protection Agency inventory. We used aircraft mole fraction measurements from nine research flights to optimize the high-resolution inventory emissions within a Bayesian inversion. These sectorally optimized emissions show that the high-resolution inventory still significantly underestimates methane emissions within the New York-Newark urban area, primarily because it underestimates emissions from thermogenic sources (by a factor of 2.3). This suggests that there remains a gap in our process-based understanding of urban methane emissions.

The Total Carbon Column Observing Network's GGG2020 data version

Abstract. The Total Carbon Column Observing Network (TCCON) measures column-average mole fractions of several greenhouse gases (GHGs), beginning in 2004, from over 30 current or past measurement sites around the world using solar absorption spectroscopy in the near-infrared (near-IR) region. TCCON GHG data have been used extensively for multiple purposes, including in studies of the carbon cycle and anthropogenic emissions, as well as to validate and improve observations from space-based sensors. Here, we describe an update to the retrieval algorithm used to process the TCCON near-IR solar spectra and to generate the associated data products. This version, called GGG2020, was initially released in April 2022. It includes updates and improvements to all steps of the retrieval, including but not limited to the conversion of the original interferograms into spectra, the spectroscopic information used in the column retrieval, post hoc air mass dependence correction, and scaling to align with the calibration scales of in situ GHG measurements. All TCCON data are available through https://tccondata.org/ (last access: 22 April 2024) and are hosted on CaltechDATA (https://data.caltech.edu/, last access: 22 April 2024). Each TCCON site has a unique DOI for its data record. An archive of all the sites' data is also available with the DOI https://doi.org/10.14291/TCCON.GGG2020 (Total Carbon Column Observing Network (TCCON) Team, 2022). The hosted files are updated approximately monthly, and TCCON sites are required to deliver data to the archive no later than 1 year after acquisition. Full details of data locations are provided in the “Code and data availability” section.

Greenhouse gas fluxes of microbial‐induced calcite precipitation at varying urea‐to‐calcium concentrations

AbstractMicrobial‐induced calcite precipitation (MICP) is regarded as environmentally friendly, partly due to the storage of carbon as carbonates. Although CO2 emissions during MICP have been reported, quantification of its environmental impact regarding total greenhouse gas fluxes has not yet been thoroughly investigated. In particular, N2O fluxes could occur in addition to CO2 since MICP involves the microbially mediated nitrogen cycle. This study investigated the greenhouse gas fluxes during biostimulation of MICP in quartz sand in incubation experiments. Soil samples were treated with MICP cementation solution containing calcium concentrations of 0, 20, 100 and 200 mM at a fixed urea concentration of 100 mM to offer a range of carbonation potential and/or mitigation of CO2 emissions. Greenhouse gas (CO2, CH4 and N2O) measurements were determined by gas chromatography during incubations. Soil total inorganic carbon and the isotopic composition of precipitated and emitted CO2 were determined by isotope ratio mass spectrometry. CO2 emissions (0.52 to 4.08 μg of CO2–C h−1 g−1 soil) resulted from MICP, while N2O and CH4 fluxes were not detected. Increasing Ca2+ with respect to urea resulted in lower CO2 emissions, lower solution pH, similar carbonate precipitation and urea hydrolysis inhibition. The highest urea‐to‐calcium ratio (1:0.2) emitted roughly two times the amount of CO2 (112 μg of CO2–C g−1 soil) compared to the 1:1 and 1:2 ratios (47 to 58 μg of CO2–C g−1 soil) and five to six times more than samples that did not receive Ca2+ (1:0) (~18 μg of CO2–C g−1 soil). Precipitated CaCO3–C was tenfold higher than cumulative emitted CO2–C, and isotopic analysis indicated both emitted and precipitated carbon were of urea origin. Both emitted and precipitated carbon accounted for a very low percentage of total carbon applied in the system (&lt;0.35 and &lt;4.5%, respectively), presumably due to limited urea hydrolysis which was negatively affected by increasing the Ca2+ concentration.

Characterizing urban GHG emissions based on land-use change—A case of Airport New City

Measuring greenhouse gas (GHG) emissions across different types of land is essential for urban planning during the transition to low-carbon cities. Urban land identification, based on remote sensing images and points of interest (POIs), has the potential to narrow down the statistical unit, helping achieve spatial visualization of GHG emissions below the city level and distinguish emission characteristics of different land-use types. Considering land type as a classification standard for GHG emissions, we constructed the modified STRIPAT-PLS model by identifying land-use types, reconstructing land-use GHG emissions (LUGEs) inventory, and extracting driving indexes, which calculated driving force and LUGEs that were missed in historical years. It deepened the depth and precision of GHG emissions research and provided a reference for LUGE reduction and land management below the city level where missing historical data on GHG inventories. The results showed that: 1) the modified STRIPAT-PLS model achieved a simulation accuracy of 94.9%, demonstrating the effectiveness of our research approach in depicting GHG emissions across different land-use types. 2) Land scale, socio-economic development, and industrial development were key factors that impacted agricultural land, residential land, and airport respectively. 3) Airport was the most significant carbon contributor, while industrial witnessed the highest growth in emission intensity; 4) the spatial analysis indicated decreasing differences in GHG emissions and an overall increase in emission intensity. In addition, the research proposed emission reduction priorities and strategies for each land type to promote low-carbon goals in airport cities.

3-Levers of Emission Control-Modeling Framework: Modeling GHG Emissions When Direct Measurement is not Possible

The Corporate Sustainability Reporting Directive (CSRD) requires the measurement and reporting of the greenhouse gas (GHG) emissions of companies and products in CO2-equivalent, considering all stages of their Life Cycle Assessment (LCA) where scopes 1, 2, and 3 emission categories are included. The GHG Protocol Product Life Cycle Accounting and Reporting Standard distinguishes between the “direct measurement” and ”indirect measurement”, i.e. activity-based measurement. The most accurate method would be to directly measure the GHG emissions. However, in many companies, this is not possible due to the unavailability of adequate measurement sensorics. For the activity-based LCA, the ISO14000 family of standards constructs an environmental management system by using a “technical” terminology. In contrast to that, the “E-Liability Accounting System” from Kaplan/Ramanna is casted in the language of financial and cost accounting. Accordingly, it presents the LCA of products GHG emission in a well-established and familiar theoretical foundation. The E-Liability Accounting System is constructed mainly at the conceptual level, as the activity-based GHG measurement and the distinction of scopes 1, 2, and 3 are not really operationalized. In this paper, these limitations are addressed by operationalizing the E-Liability Accounting System within the “3 Levers of Emission Control (3-LoEC)-modeling framework”. This framework allows the explicit specification of activity-based GHG measurement metrics all over the product’s life cycle. Due to the CSRD compliance, the 3-LoEC-modeling framework possesses practical validity. This carries over to its derived metrics. The applicability of the 3-LoEC-metrics is demonstrated in a use case, where a “food-bowl” is produced via injection molding technology.