Universal differential equations for glacier ice flow modelling Geoscientific Model Development DOI 10.5194/gmd-16-6671-2023 15 November 2023 We developed a new modelling framework combining numerical methods with machine learning. Using this approach, we focused on understanding how ice moves within glaciers, and we successfully learnt a prescribed law describing ice movement for 17 glaciers worldwide as a proof of concept. Our framework has the potential to discover important laws governing glacier processes, aiding our understanding of glacier physics and their contribution to water resources and sea-level rise. Read more
Machine learning for numerical weather and climate modelling: a review Geoscientific Model Development DOI 10.5194/gmd-16-6433-2023 13 November 2023 Machine learning (ML) is an increasingly popular tool in the field of weather and climate modelling. While ML has been used in this space for a long time, it is only recently that ML approaches have become competitive with more traditional methods. In this review, we have summarized the use of ML in weather and climate modelling over time; provided an overview of key ML concepts, methodologies, and terms; and suggested promising avenues for further research. Read more
ESD Ideas: Arctic amplification’s contribution to breaches of the Paris Agreement Earth System Dynamics DOI 10.5194/esd-14-1165-2023 10 November 2023 The Arctic is warming several times faster than the rest of the planet. Here, we use climate model projections to quantify for the first time how this faster warming in the Arctic impacts the timing of crossing the 1.5 °C and 2 °C thresholds defined in the Paris Agreement. We show that under plausible emissions scenarios that fail to meet the Paris 1.5 °C target, a hypothetical world without faster warming in the Arctic would breach that 1.5 °C target around 5 years later. Read more
Opinion: A critical evaluation of the evidence for aerosol invigoration of deep convection Atmospheric Chemistry and Physics DOI 10.5194/acp-23-13791-2023 8 November 2023 As atmospheric particles called aerosols increase in number, the number of droplets in clouds tends to increase, which has been theorized to increase storm intensity. We critically evaluate the evidence for this theory, showing that flaws and limitations of previous studies coupled with unaddressed cloud process complexities draw it into question. We provide recommendations for future observations and modelling to overcome current uncertainties. Read more
Mechanisms controlling giant sea salt aerosol size distributions along a tropical orographic coastline Atmospheric Chemistry and Physics DOI 10.5194/acp-23-13735-2023 6 November 2023 Sea salt aerosol is an important marine aerosol that may be produced in greater quantities in coastal regions than over the open ocean. This study observed these particles along the windward coastline of O’ahu, Hawai’i, to understand how wind and waves influence their production and dispersal. Overall, wave heights were the strongest variable correlated with changes in aerosol concentrations, while wind speeds played an important role in their horizontal dispersal and vertical mixing. Read more
Rejuvenating the ocean: mean ocean radiocarbon, CO2 release, and radiocarbon budget closure across the last deglaciation Climate of the Past DOI 10.5194/cp-19-2177-2023 3 November 2023 Radiocarbon is best known as a dating tool, but it also allows us to track CO2 exchange between the ocean and atmosphere. Using decades of data and novel mapping methods, we have charted the ocean’s average radiocarbon ″age” since the last Ice Age. Combined with climate model simulations, these data quantify the ocean’s role in atmospheric CO2 rise since the last Ice Age while also revealing that Earth likely received far more cosmic radiation during the last Ice Age than hitherto believed. Read more
Rate-induced tipping in ecosystems and climate: the role of unstable states, basin boundaries and transient dynamics Nonlinear Processes in Geophysics DOI 10.5194/npg-30-481-2023 1 November 2023 Many systems in nature are characterized by the coexistence of different stable states for given environmental parameters and external forcing. Examples can be found in different fields of science, ranging from ecosystems to climate dynamics. Perturbations can lead to critical transitions (tipping) from one stable state to another. The study of these transitions requires the development of new methodological approaches that allow for modelling, analysing and predicting them. Read more
A spectrum of geoscience communication: from dissemination to participation Geoscience Communication DOI 10.5194/gc-6-131-2023 30 October 2023 In this article, I explore the various ways the geosciences can be communicated to a wider audience. I focus on creative methods that range from sharing information to involving the public in the research process. By using examples from my own work and the wider literature, I demonstrate how these approaches can engage diverse communities and promote greater recognition for geoscience communication. Read more
N2O as a regression proxy for dynamical variability in stratospheric trace gas trends Atmospheric Chemistry and Physics DOI 10.5194/acp-23-13283-2023 27 October 2023 This paper presents a technique for understanding the causes of long-term changes in stratospheric composition. By using N2O as a proxy for stratospheric circulation in the model used to calculated trends, it is possible to separate the effects of dynamics and chemistry on observed trace gas trends. We find that observed HCl increases are due to changes in the stratospheric circulation, as are O3 decreases above 30 hPa in the Northern Hemisphere. Read more
Opinion: Recent developments and future directions in studying the mesosphere and lower thermosphere Atmospheric Chemistry and Physics DOI 10.5194/acp-23-13255-2023 25 October 2023 The mesosphere or lower thermosphere region of the atmosphere borders the edge of space. It is subject to extreme ultraviolet photons and charged particles from the Sun and atmospheric gravity waves from below, which tend to break in this region. The pressure is very low, which facilitates chemistry involving species in excited states, and this is also the region where cosmic dust ablates and injects various metals. The result is a unique and exotic chemistry. Read more
Mapping Antarctic crevasses and their evolution with deep learning applied to satellite radar imagery The Cryosphere DOI 10.5194/tc-17-4421-2023 23 October 2023 The presence of crevasses in Antarctica influences how the ice sheet behaves. It is important, therefore, to collect data on the spatial distribution of crevasses and how they are changing. We present a method of mapping crevasses from satellite radar imagery and apply it to 7.5 years of images, covering Antarctica’s floating and grounded ice. We develop a method of measuring change in the density of crevasses and quantify increased fracturing in important parts of the West Antarctic Ice Sheet. Read more
ESD Ideas: Translating historical extreme weather events into a warmer world Earth System Dynamics DOI 10.5194/esd-14-1081-2023 20 October 2023 Adapting to climate change requires an understanding of how extreme weather events are changing. We propose a new approach to examine how the consequences of a particular weather pattern have been made worse by climate change, using an example of a severe windstorm that occurred in 1903. When this storm is translated into a warmer world, it produces higher wind speeds and increased rainfall, suggesting that this storm would be more damaging if it occurred today rather than 120 years ago. Read more
Global observations of aerosol indirect effects from marine liquid clouds Atmospheric Chemistry and Physics DOI 10.5194/acp-23-13125-2023 18 October 2023 Interactions between aerosol pollution and liquid clouds are one of the largest sources of uncertainty in the effective radiative forcing of climate over the industrial era. We use global satellite observations to decompose the forcing into components from changes in cloud-droplet number concentration, cloud water content, and cloud amount. Our results reduce uncertainty in these forcing components and clarify their relative importance. Read more
Technical note: NASAaccess – a tool for access, reformatting, and visualization of remotely sensed earth observation and climate data Hydrology and Earth System Sciences DOI 10.5194/hess-27-3621-2023 16 October 2023 We present an open-source platform in response to the NASA Open-Source Science Initiative for accessing and presenting quantitative remote-sensing earth observation,and climate data. With our platform scientists, stakeholders and concerned citizens can engage in the exploration, modelling, and understanding of data. We envisioned this platform as lowering the technical barriers and simplifying the process of accessing and leveraging additional modelling frameworks for data. Read more
The dehydration carousel of stratospheric water vapor in the Asian summer monsoon anticyclone Atmospheric Chemistry and Physics DOI 10.5194/acp-23-12935-2023 13 October 2023 We studied water vapour in a critical region of the atmosphere, the Asian summer monsoon anticyclone, using rare in situ observations. Our study shows that extremely high water vapour values observed in the stratosphere within the Asian monsoon anticyclone still undergo significant freeze-drying and that water vapour concentrations set by the Lagrangian dry point are a better proxy for the stratospheric water vapour budget than rare observations of enhanced water mixing ratios. Read more
Late Cenozoic sea-surface-temperature evolution of the South Atlantic Ocean Climate of the Past DOI 10.5194/cp-19-1931-2023 11 October 2023 We present two new sea surface temperature (SST) records in comparison with available SST records to reconstruct South Atlantic paleoceanographic evolution. Our results show a low SST gradient in the Eocene–early Oligocene due to the persistent gyral circulation. A higher SST gradient in the Middle–Late Miocene infers a stronger circumpolar current. The southern South Atlantic was the coldest region in the Southern Ocean and likely the main deep-water formation location in the Middle Miocene. Read more
Soil-biodegradable plastic films do not decompose in a lake sediment over 9 months of incubation Biogeosciences DOI 10.5194/bg-20-4213-2023 9 October 2023 Agriculture relies heavily on plastic mulch films, which may be transported to aquatic environments. We investigated the breakdown of soil-biodegradable agricultural mulch films in lake sediments. After 40 weeks, films were intact, and no significant CO2 or CH4 was produced from the biodegradable mulch films. We conclude that the mulch films we used have a low biodegradability in lake sediments. The sediment lacks the microbes needed to break down the biodegradable plastics that were used here. Read more
Linear polarization signatures of atmospheric dust with the SolPol direct-sun polarimeter Atmospheric Measurement Techniques DOI 10.5194/amt-16-4529-2023 6 October 2023 Atmospheric dust particles may present a preferential alignment due to their shape on long range transport. Since dust is abundant and plays a key role to global climate, the elusive observation of orientation will be a game changer to existing measurement techniques and the representation of particles in climate models. We utilize a specifically designed instrument, SolPol, and target the Sun from the ground for large polarization values under dusty conditions, a clear sign of orientation. Read more
Biomineralization of amorphous Fe-, Mn- and Si-rich mineral phases by cyanobacteria under oxic and alkaline conditions Biogeosciences DOI 10.5194/bg-20-4183-2023 4 October 2023 Iron and manganese are poorly soluble in oxic and alkaline solutions but much more soluble under anoxic conditions. As a result, authigenic minerals rich in Fe and/or Mn have been viewed as diagnostic of anoxic conditions. However, here we reveal a new case of biomineralization by specific cyanobacteria, forming abundant Fe(III)- and Mn(IV)-rich amorphous phases under oxic conditions in an alkaline lake. This might be an overlooked biotic contribution to the scavenging of Fe from water columns. Read more
Rapid saturation of cloud water adjustments to shipping emissions Atmospheric Chemistry and Physics DOI 10.5194/acp-23-12545-2023 2 October 2023 Aerosol from burning fuel changes cloud properties, e.g., the number of droplets and the content of water. Here, we study how clouds respond to different amounts of shipping aerosol. Droplet numbers increase linearly with increasing aerosol over a broad range until they stop increasing, while the amount of liquid water always increases, independently of emission amount. These changes in cloud properties can make them reflect more or less sunlight, which is important for the earth’s climate. Read more
SI-traceable validation of a laser spectrometer for balloon-borne measurements of water vapor in the upper atmosphere Atmospheric Measurement Techniques DOI 10.5194/amt-16-4391-2023 29 September 2023 The abundance of water vapor (H2O) in the upper atmosphere has a significant impact on the rate of global warming. We developed a new lightweight spectrometer (ALBATROSS) for H2O measurements aboard meteorological balloons. Here, we assess the accuracy and precision of ALBATROSS using metrology-grade reference gases. The results demonstrate the exceptional potential of mid-infrared laser absorption spectroscopy as a new reference method for in situ measurements of H2O in the upper atmosphere. Read more
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution Geoscientific Model Development DOI 10.5194/gmd-16-5561-2023 27 September 2023 The columnar approach of gravity wave (GW) schemes results in dynamical model biases, but parallel decomposition makes horizontal GW propagation computationally unfeasible. In the global model EMAC, we approximate it by GW redistribution at one altitude using tailor-made redistribution maps generated with a ray tracer. More spread-out GW drag helps reconcile the model with observations and close the 60°S GW gap. Polar vortex dynamics are improved, enhancing climate model credibility. 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
Element ∕ Ca ratios in Nodosariida (Foraminifera) and their potential application for paleoenvironmental reconstructions Biogeosciences DOI 10.5194/bg-20-4043-2023 22 September 2023 We analyzed Mg / Ca and other El / Ca (Na / Ca, B / Ca, Sr / Ca and Ba / Ca) in Nodosariata. Their calcite chemistry is markedly different to that of the other calcifying orders of foraminifera. We show a relation between the species average Mg / Ca and its sensitivity to changes in temperature. Differences were reflected in both the Mg incorporation and the sensitivities of Mg / Ca to temperature. Read more
Advancing the estimation of future climate impacts within the United States Earth System Dynamics DOI 10.5194/esd-14-1015-2023 20 September 2023 This study utilizes a reduced-complexity model, Framework for Evaluating Damages and Impacts (FrEDI), to assess the impacts from climate change in the United States across 10 000 future probabilistic emission and socioeconomic projections. Climate-driven damages are largest for the health category, with the majority of damages in this category coming from the valuation estimates of premature mortality attributable to climate-driven changes in extreme temperature and air quality scenarios. Read more
Molecular simulations reveal that heterogeneous ice nucleation occurs at higher temperatures in water under capillary tension Atmospheric Chemistry and Physics DOI 10.5194/acp-23-10625-2023 18 September 2023 Using computer simulations of water, we find that water under tension freezes more easily than under normal conditions. A linear equation describes how freezing temperature increases with tension. Accordingly, simulations show that naturally occurring tension in water capillary bridges leads to higher freezing temperatures. This work is an early step in determining if atmospheric cloud droplets freeze due to naturally occurring tension, for example, during processes such as droplet collisions. Read more
Modes of Antarctic tidal grounding line migration revealed by Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) laser altimetry The Cryosphere DOI 10.5194/tc-17-4079-2023 15 September 2023 We develop a method using ICESat-2 data to measure how Antarctic grounding lines (GLs) migrate across the tide cycle. At an ice plain on the Ronne Ice Shelf we observe 15 km of tidal GL migration, the largest reported distance in Antarctica, dominating any signal of long-term migration. We identify four distinct migration modes, which provide both observational support for models of tidal ice flexure and GL migration and insights into ice shelf–ocean–subglacial interactions in grounding zones. Read more
High-resolution data reveal a surge of biomass loss from temperate and Atlantic pine forests, contextualizing the 2022 fire season distinctiveness in France Biogeosciences DOI 10.5194/bg-20-3803-2023 13 September 2023 This study analyses the ecological impact of the 2022 summer fire season in France by using high-resolution satellite data. The total biomass loss was 2.553 Mt, equivalent to a 17 % increase of the average natural mortality of all French forests. While Mediterranean forests had a lower biomass loss, there was a drastic increase in burned area and biomass loss over the Atlantic pine forests and temperate forests. This result revisits the distinctiveness of the 2022 fire season. Read more
Atmospheric drivers of melt-related ice speed-up events on the Russell Glacier in southwest Greenland The Cryosphere DOI 10.5194/tc-17-3933-2023 11 September 2023 The Greenland Ice Sheet contributes strongly to sea level rise in the warming climate. One process that can affect the ice sheet’s mass balance is short-term ice speed-up events. These can be caused by high melting or rainfall as the water flows underneath the glacier and allows for faster sliding. In this study we found three main weather patterns that cause such ice speed-up events on the Russell Glacier in southwest Greenland and analysed how they induce local melting and ice accelerations. Read more
Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere Annales Geophysicae DOI 10.5194/angeo-41-339-2023 8 September 2023 The relation between electron, ion and neutral temperatures in the lower thermosphere–ionosphere (LTI) is key to understanding the energy balance and transfer between species. However, their simultaneous measurement is rare in the LTI. Based on data from the AE-C, AE-D, AE-E and DE-2 satellites of the 1970s and 1980s, a large number of events where neutrals are hotter than ions are identified and statistically analysed. Potential mechanisms that could trigger these events are proposed. Read more
Calibration of groundwater seepage against the spatial distribution of the stream network to assess catchment-scale hydraulic properties Hydrology and Earth System Sciences DOI 10.5194/hess-27-3221-2023 6 September 2023 We propose a model calibration method constraining groundwater seepage in the hydrographic network. The method assesses the hydraulic properties of aquifers in regions where perennial streams are directly fed by groundwater. The estimated hydraulic conductivity appear to be highly sensitive to the spatial extent and density of streams. Such an approach improving subsurface characterization from surface information is particularly interesting for ungauged basins. Read more
Opinion: Atmospheric multiphase chemistry – past, present, and future Atmospheric Chemistry and Physics DOI 10.5194/acp-23-9765-2023 4 September 2023 With important climate and air quality impacts, atmospheric multiphase chemistry involves gas interactions with aerosol particles and cloud droplets. We summarize the status of the field and discuss potential directions for future growth. We highlight the importance of a molecular-level understanding of the chemistry, along with atmospheric field studies and modelling, and emphasize the necessity for atmospheric multiphase chemists to interact widely with scientists from neighbouring disciplines. Read more
Atmospheric CO2 inversion reveals the Amazon as a minor carbon source caused by fire emissions, with forest uptake offsetting about half of these emissions Atmospheric Chemistry and Physics DOI 10.5194/acp-23-9685-2023 1 September 2023 The Amazon’s carbon balance may have changed due to forest degradation, deforestation and warmer climate. We used an atmospheric model and atmospheric CO2 observations to quantify Amazonian carbon emissions (2010–2018). The region was a small carbon source to the atmosphere, mostly due to fire emissions. Forest uptake compensated for ~ 50 % of the fire emissions, meaning that the remaining forest is still a small carbon sink. We found no clear evidence of weakening carbon uptake over the period. Read more
Brief communication: The Glacier Loss Day as an indicator of a record-breaking negative glacier mass balance in 2022 The Cryosphere DOI 10.5194/tc-17-3661-2023 25 August 2023 The Glacier Loss Day (GLD) is the day on which all mass gained from the accumulation period is lost, and the glacier loses mass irrecoverably for the rest of the mass balance year. In 2022, the GLD was already reached on 23 June at Hintereisferner (Austria), and this led to a record-breaking mass loss. We introduce the GLD as a gross yet expressive indicator of the glacier’s imbalance with a persistently warming climate. Read more
A rise in HFC-23 emissions from eastern Asia since 2015 Atmospheric Chemistry and Physics DOI 10.5194/acp-23-9401-2023 23 August 2023 Based on atmospheric HFC-23 observations, the first estimate of post-CDM HFC-23 emissions in eastern Asia for 2008-2019 shows that these emissions contribute significantly to the global emissions rise. The observation-derived emissions were much larger than the bottom-up estimates expected to approach zero after 2015 due to national abatement activities. These discrepancies could be attributed to unsuccessful factory-level HFC-23 abatement and inaccurate quantification of emission reductions. Read more
Stagnant ice and age modelling in the Dome C region, Antarctica The Cryosphere DOI 10.5194/tc-17-3461-2023 21 August 2023 We combined a numerical model with radar measurements in order to determine the age of ice in the Dome C region of Antarctica. Our results show that at the current ice core drilling sites on Little Dome C, the maximum age of the ice is almost 1.5 Ma. We also highlight a new potential drill site called North Patch with ice up to 2 Ma. Finally, we explore the nature of a stagnant ice layer at the base of the ice sheet which has been independently observed and modelled but is not well understood. Read more
Widespread slowdown in thinning rates of West Antarctic ice shelves The Cryosphere DOI 10.5194/tc-17-3409-2023 18 August 2023 We report on a slowdown in the rate of thinning and melting of West Antarctic ice shelves. We present a comprehensive assessment of the Antarctic ice shelves, where we analyse at a continental scale the changes in thickness, flow, and basal melt over the past 26 years. We also present a novel method to estimate ice shelf change from satellite altimetry and a time-dependent data set of ice shelf thickness and basal melt rates at an unprecedented resolution. Read more
New ring shear deformation apparatus for three-dimensional multiphase experiments: first results Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-12-141-2023 16 August 2023 Multiple geologic hazards, such as landslides and earthquakes, arise when solids and fluids coexist and deform together. We designed an experimental apparatus that allows us to observe such deformation in 3D. The first results show how fluids and solids deform and break at the same time, allowing us to study the impact of both materials on deformation distribution and speed. Making these processes visible has the potential to improve risk assessments associated with geological hazards. Read more
Potential bioavailability of representative pyrogenic organic matter compounds in comparison to natural dissolved organic matter pools Biogeosciences DOI 10.5194/bg-20-3449-2023 14 August 2023 Intensifying wildfires are increasing pyrogenic organic matter (PyOM) production and its impact on water quality. Recent work indicates that PyOM may have a greater impact on aquatic biogeochemistry than previously assumed, driven by higher bioavailability. We provide a full assessment of the potential bioavailability of PyOM across its chemical spectrum. We indicate that PyOM can be actively transformed within the river corridor and, therefore, may be a growing source of riverine C emissions. Read more
Drone-based meteorological observations up to the tropopause – a concept study Atmospheric Measurement Techniques DOI 10.5194/amt-16-3739-2023 11 August 2023 The first atmospheric soundings with an electrically powered small uncrewed aircraft system (UAS) up to an altitude of 10 km are presented and assessed for quality, revealing the potential to augment atmospheric observations and fill observation gaps for numerical weather prediction. This is significant because of the need for high-resolution meteorological data, in particular in remote areas with limited in situ measurements, and for reference data for satellite measurement calibration. Read more
The EarthCARE mission – science and system overview Atmospheric Measurement Techniques DOI 10.5194/amt-16-3581-2023 9 August 2023 The EarthCARE satellite is due for launch in 2024. It includes four scientific instruments to measure global vertical profiles of aerosols, clouds and precipitation properties together with radiative fluxes and derived heating rates. The mission’s scientific requirements, the satellite and the ground segment are described. In particular, the four scientific instruments and their performance are described at the level of detail required by mission data users. Read more
The three-dimensional structure of fronts in mid-latitude weather systems in numerical weather prediction models Geoscientific Model Development DOI 10.5194/gmd-16-4427-2023 7 August 2023 We investigate the benefit of objective 3-D front detection with modern interactive visual analysis techniques for case studies of extra-tropical cyclones and comparisons of frontal structures between different numerical weather prediction models. The 3-D frontal structures show agreement with 2-D fronts from surface analysis charts and augment them in the vertical dimension. We see great potential for more complex studies of atmospheric dynamics and for operational weather forecasting. Read more
DSCIM-Coastal v1.1: an open-source modeling platform for global impacts of sea level rise Geoscientific Model Development DOI 10.5194/gmd-16-4331-2023 4 August 2023 This work presents a novel open-source modelling platform for evaluating future sea level rise (SLR) impacts. Using nearly 10 000 discrete coastline segments around the world, we estimate 21st-century costs for 230 SLR and socioeconomic scenarios. We find that annual end-of-century costs range from USD 100 billion under a 2 °C warming scenario with proactive adaptation to 7 trillion under a 4 °C warming scenario with minimal adaptation, illustrating the cost-effectiveness of coastal adaptation. Read more
Detection of large-scale cloud microphysical changes within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-8259-2023 2 August 2023 Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds. Read more
Design and performance of the Hotrod melt-tip ice-drilling system Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-12-121-2023 31 July 2023 We describe a new drill for glaciers and ice sheets. Instead of drilling down into the ice, via mechanical action, our drill melts into the ice. Our goal is simply to pull a cable of temperature sensors on a one-way trip down to the ice–bed interface. Here, we describe the design and testing of our drill. Under laboratory conditions, our melt-tip drill has an efficiency of ~35 % with a theoretical maximum penetration rate of ~12 m h^-1. Under field conditions, our efficiency is just ~15 %. Read more
Continuous weekly monitoring of methane emissions from the Permian Basin by inversion of TROPOMI satellite observations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-7503-2023 28 July 2023 We use TROPOMI satellite observations to quantify weekly methane emissions from the US Permian oil and gas basin from May 2018 to October 2020. We find that Permian emissions are highly variable, with diverse economic and activity drivers. The most important drivers during our study period were new well development and natural gas price. Permian methane intensity averaged 4.6% and decreased by 1% per year. Read more
Brief communication: How deep is the snow on Mount Everest? The Cryosphere DOI 10.5194/tc-17-2625-2023 26 July 2023 There is very strong scientific and public interest regarding the snow thickness on Mountain Everest. Previously reported snow depths derived by different methods and instruments ranged from 0.92 to 3.5 m. Our measurements in 2022 provide the first clear radar image of the snowpack at the top of Mount Everest. The snow thickness at Earth’s summit was averaged to be 9.5 ± 1.2 m. This updated snow thickness is considerably deeper than values reported during the past 5 decades. Read more
All about nitrite: exploring nitrite sources and sinks in the eastern tropical North Pacific oxygen minimum zone Biogeosciences DOI 10.5194/bg-20-2499-2023 24 July 2023 Nitrogen (N) is essential for life; thus, its availability plays a key role in determining marine productivity. Using incubations of seawater spiked with a rare form of N measurable on a mass spectrometer, we quantified microbial pathways that determine marine N availability. The results show that pathways that recycle N have higher rates than those that result in its loss from biomass and present new evidence for anaerobic nitrite oxidation, a process long thought to be strictly aerobic. Read more
Review article: Large fluctuations in non-equilibrium physics Nonlinear Processes in Geophysics DOI 10.5194/npg-30-253-2023 21 July 2023 Non-equilibrium is dominant in geophysical and climate phenomena. Most of the processes that characterize energy flow occur far from equilibrium. These range from very large systems, such as weather patterns or ocean currents that remain far from equilibrium, owing to an influx of energy, to biological structures. In the last decades, progress in non-equilibrium physics has come from the study of very rare fluctuations, and this paper provides an introduction to these theoretical developments. Read more
Dense water formation in the eastern Mediterranean under a global warming scenario Ocean Science DOI 10.5194/os-19-941-2023 19 July 2023 Global warming may strongly affect dense water formation in the eastern Mediterranean, potentially impacting basin circulation and water properties. We find that at the end of the century dense water formation is reduced by 75 % for the Adriatic, 84 % for the Aegean, and 83 % for the Levantine Sea. This reduction is caused by changes in the temperature and salinity of surface and intermediate waters, which strengthen the vertical stratification, hampering deep convection. Read more