Opinion: The strength of long-term comprehensive observations to meet multiple grand challenges in different environments and in the atmosphere Atmospheric Chemistry and Physics DOI 10.5194/acp-23-14949-2023 1 December 2023 To be able to meet global grand challenges, we need comprehensive open data with proper metadata. In this opinion paper, we describe the SMEAR (Station for Measuring Earth surface – Atmosphere Relations) concept and include several examples (cases), such as new particle formation and growth, feedback loops and the effect of COVID-19, and what has been learned from these investigations. The future needs and the potential of comprehensive observations of the environment are summarized. Read more
Simulated hydrological effects of grooming and snowmaking in a ski resort on the local water balance Hydrology and Earth System Sciences DOI 10.5194/hess-27-4257-2023 29 November 2023 Ski resorts are a key socio-economic asset of several mountain areas. Grooming and snowmaking are routinely used to manage the snow cover on ski pistes, but despite vivid debate, little is known about their impact on water resources downstream. This study quantifies, for the pilot ski resort La Plagne in the French Alps, the impact of grooming and snowmaking on downstream river flow. Hydrological impacts are mostly apparent at the seasonal scale and rather neutral on the annual scale. Read more
Constraining an eddy energy dissipation rate due to relative wind stress for use in energy budget-based eddy parameterisations Ocean Science DOI 10.5194/os-19-1669-2023 27 November 2023 The dissipation rate of eddy energy in current energy budget-based eddy parameterisations is still relatively unconstrained, leading to uncertainties in ocean transport and ocean heat uptake. Here, we derive a dissipation rate due to the interaction of surface winds and eddy currents, a process known to significantly damp ocean eddies. The dissipation rate is quantified using seasonal climatology and displays wide spatial variability, with some of the largest values found in the Southern Ocean. 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
Responses of globally important phytoplankton species to olivine dissolution products and implications for carbon dioxide removal via ocean alkalinity enhancement Biogeosciences DOI 10.5194/bg-20-4669-2023 22 November 2023 Applications of the mineral olivine are a promising means to capture carbon dioxide via coastal enhanced weathering, but little is known about the impacts on important marine phytoplankton. We examined the effects of olivine dissolution products on species from three major phytoplankton groups: diatoms, coccolithophores, and cyanobacteria. Growth and productivity were generally either unaffected or stimulated, suggesting the effects of olivine on key phytoplankton are negligible or positive. Read more
Land cover and management effects on ecosystem resistance to drought stress Earth System Dynamics DOI 10.5194/esd-14-1211-2023 20 November 2023 Ecosystem resistance reflects their susceptibility during adverse conditions and can be changed by land management. We estimate ecosystem resistance to drought and temperature globally. We find a higher resistance to drought in forests compared to croplands and an evident loss of resistance to drought when primary forests are converted to secondary forests or they are harvested. Old-growth trees tend to be more resistant in some forests and crops benefit from irrigation during drought periods. Read more
Southern Ocean warming and Antarctic ice shelf melting in conditions plausible by late 23rd century in a high-end scenario Ocean Science DOI 10.5194/os-19-1595-2023 17 November 2023 How much the Antarctic ice shelf basal melt rate can increase in response to global warming remains an open question. To achieve this, we compared an ocean simulation under present-day atmospheric condition to a one under late 23rd century atmospheric conditions. The ocean response to the perturbation includes a decrease in the production of cold dense water and an increased intrusion of warmer water onto the continental shelves. This induces a substantial increase in ice shelf basal melt rates. Read more
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