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
Brief communication: Rapid ∼ 335 × 106 m3 bed erosion after detachment of the Sedongpu Glacier (Tibet) The Cryosphere DOI 10.5194/tc-17-2533-2023 17 July 2023 Following the detachment of the 130 × 10^6 m^3 Sedongpu Glacier (south-eastern Tibet) in 2018, the Sedongpu Valley underwent massive large-volume landscape changes. An enormous volume of in total around 330 × 10^6 m^3 was rapidly eroded, forming a new canyon of up to 300 m depth, 1 km width, and almost 4 km length. Such consequences of glacier change in mountains have so far not been considered at this magnitude and speed. Read more
Impact of deoxygenation and warming on global marine species in the 21st century Biogeosciences DOI 10.5194/bg-20-2425-2023 14 July 2023 Ocean temperature and oxygen shape marine habitats together with species’ characteristics. We calculated the impacts of projected 21st-century warming and oxygen loss on the contemporary habitat volume of 47 marine species and described the drivers of these impacts. Most species lose less than 5 % of their habitat at 2 ◦C of global warming, but some species incur losses 2–3 times greater than that. We also calculate which species may be most vulnerable to climate change and why this is the case. Read more
Impact of a strong volcanic eruption on the summer middle atmosphere in UA-ICON simulations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-7001-2023 12 July 2023 Strong volcanic eruptions are able to alter the temperature and the circulation of the middle atmosphere. This study simulates the atmospheric response to an idealized strong tropical eruption and focuses on the impact on the mesosphere. The simulations show a warming of the polar summer mesopause in the first November after the eruption. Our study indicates that this is mainly due to dynamical coupling in the summer hemisphere with a potential contribution from interhemispheric coupling. Read more
Quantifying land carbon cycle feedbacks under negative CO2 emissions Biogeosciences DOI 10.5194/bg-20-2283-2023 10 July 2023 We propose a new method to quantify carbon cycle feedbacks under negative CO2 emissions. Our method isolates the lagged carbon cycle response to preceding positive emissions from the response to negative emissions. Our findings suggest that feedback parameters calculated with the novel approach are larger than those calculated with the conventional approach whereby carbon cycle inertia is not corrected for, with implications for the effectiveness of carbon dioxide removal in reducing CO2 levels. Read more
Particle shapes and infrared extinction spectra of nitric acid dihydrate (NAD) crystals: optical constants of the β-NAD modification Atmospheric Chemistry and Physics DOI 10.5194/acp-23-6789-2023 7 July 2023 Polar stratospheric clouds (PSCs) play an important role in the depletion of stratospheric ozone. They can consist of different chemical species, including crystalline nitric acid hydrates. We found that mineral dust or meteoric ablation material can efficiently catalyse the formation of a specific phase of nitric acid dihydrate crystals. We determined predominant particle shapes and infrared optical properties of these crystals, which are important inputs for remote sensing detection of PSCs. Read more
Diurnal carbon monoxide observed from a geostationary infrared hyperspectral sounder: first result from GIIRS on board FengYun-4B Atmospheric Measurement Techniques DOI 10.5194/amt-16-3059-2023 5 July 2023 Observations from geostationary orbit provide contiguous coverage with a high temporal resolution, representing an important advancement over current low-Earth-orbit instruments. Using measurements from GIIRS on board China’s FengYun satellite, the world’s first geostationary hyperspectral infrared sounder, we showed the first results of diurnal CO in eastern Asia from a geostationary orbit, which will have great potential in improving local and global air quality and climate research. Read more