Methanesulfonic acid (MSA) migration in polar ice: data synthesis and theory The Cryosphere DOI 10.5194/tc-11-2439-2017 3 November 2017 We combine a synthesis of 22 ice core records and a model of soluble impurity transport to investigate the enigmatic, post-depositional migration of methanesulfonic acid in polar ice. Our findings suggest that migration may be universal across coastal regions of Greenland and Antarctica, though it is mitigated at sites with higher accumulation and (or) lower impurity content. Records exhibiting severe migration may still be useful for inferring decadal and lower-frequency climate variability. Read more
The importance of small artificial water bodies as sources of methane emissions in Queensland, Australia Hydrology and Earth System Sciences DOI 10.5194/hess-22-5281-2018 15 October 2018 Artificial water bodies are a major source of methane and an important contributor to flooded land greenhouse gas emissions. Past studies focussed on large water supply or hydropower reservoirs with small artificial water bodies (ponds) almost completely ignored. This regional study demonstrated ponds accounted for one-third of flooded land surface area and emitted over 1.6 million t CO2eq. yr−1(10 % of land use sector emissions). Ponds should be included in regional GHG inventories. Read more
Methanethiol, dimethyl sulfide and acetone over biologically productive waters in the southwest Pacific Ocean Atmospheric Chemistry and Physics DOI 10.5194/acp-20-3061-2020 24 March 2020 Methanethiol (MeSH) is a reduced sulfur gas originating from phytoplankton, with a global ocean source of ~ 17 % of dimethyl sulfide (DMS). It has been little studied and is rarely observed over the ocean. In this work, MeSH was measured at much higher levels than previously observed (3–36 % of parallel DMS mixing ratios). MeSH could be a significant source of atmospheric sulfur over productive regions of the ocean, but its distribution, and its atmospheric impact, requires more investigation. Read more
Remote sensing of methane leakage from natural gas and petroleum systems revisited Atmospheric Chemistry and Physics DOI 10.5194/acp-20-9169-2020 13 August 2020 The switch from the use of coal to natural gas or oil for energy generation potentially reduces the impact on global warming due to lower CO 2 emissions with the same energy content. However, this climate benefit is offset by fugitive methane emissions during the production and distribution process. We quantify emission and leakage rates relative to production for several large production regions based on satellite observations to evaluate the climate footprint of the gas and oil industry. Read more
A compact QCL spectrometer for mobile, high-precision methane sensing aboard drones Atmospheric Measurement Techniques DOI 10.5194/amt-13-4715-2020 29 September 2020 We describe a lightweight (2 kg) mid-IR laser spectrometer for airborne, in situ atmospheric methane (CH 4 ) measurements. The instrument, based on an open-path circular multipass cell, provides fast response (1 Hz) and sub-parts-per-billion precision. It can easily be mounted on a drone, giving access to highly resolved 4D (spatial and temporal) data. The performance was assessed during field deployments involving artificial CH 4 releases and vertical concentration gradients in the PBL. Read more
Methane emissions due to reservoir flushing: a significant emission pathway? Biogeosciences DOI 10.5194/bg-20-4057-2023 25 September 2023 Based on a large dataset of seasonally resolved methane (CH4) pore water concentrations in a reservoir’s sediment, we assess the significance of CH4 emissions due to reservoir flushing. In the studied reservoir, CH4 emissions caused by one flushing operation can represent 7 %–14 % of the annual CH4 emissions and depend on the timing of the flushing operation. In reservoirs with high sediment loadings, regular flushing may substantially contribute to the overall CH4 emissions. Read more
Gaps in network infrastructure limit our understanding of biogenic methane emissions for the United States Biogeosciences DOI 10.5194/bg-19-2507-2022 12 August 2022 To understand the CH4 flux potential of natural ecosystems and agricultural lands in the United States of America, a multi-scale CH4 observation network focused on CH4 flux rates, processes, and scaling methods is required. This can be achieved with a network of ground-based observations that are distributed based on climatic regions and land cover. Read more
Ground-to-UAV, laser-based emissions quantification of methane and acetylene at long standoff distances Atmospheric Measurement Techniques DOI 10.5194/amt-16-5697-2023 24 November 2023 Measurements of the emission rate of a gas or gases from point and area sources are important in a range of monitoring applications. We demonstrate a method for rapid quantification of the emission rate of multiple gases using a spatially scannable open-path sensor. The open-path spectrometer measures the total column density of gases between the spectrometer and a retroreflector mounted on an uncrewed aerial vehicle (UAV). By scanning the UAV altitude, we can determine the total gas emissions. Read more
High-resolution spatial patterns and drivers of terrestrial ecosystem carbon dioxide, methane, and nitrous oxide fluxes in the tundra Biogeosciences DOI 10.5194/bg-21-335-2024 12 January 2024 Arctic greenhouse gas (GHG) fluxes of CO2, CH4, and N2O are important for climate feedbacks. We combined extensive in situ measurements and remote sensing data to develop machine-learning models to predict GHG fluxes at a 2 m resolution across a tundra landscape. The analysis revealed that the system was a net GHG sink and showed widespread CH4 uptake in upland vegetation types, almost surpassing the high wetland CH4 emissions at the landscape scale. Read more
First validation of high-resolution satellite-derived methane emissions from an active gas leak in the UK Atmospheric Measurement Techniques DOI 10.5194/amt-17-1599-2024 18 March 2024 We provide the first validation of the satellite-derived emission estimates using surface-based mobile greenhouse gas surveys of an active gas leak detected near Cheltenham, UK. GHGSat’s emission estimates broadly agree with the surface-based mobile survey and steps were taken to fix the leak, highlighting the importance of satellite data in identifying emissions and helping to reduce our human impact on climate change. Read more