News & press Highlight articles

European Geosciences Union

www.egu.eu

Highlight articles

Some features of www.egu.eu will not appear or function properly if your browser does not have JavaScript enabled, or does not support it.

1794 items found

10 20 50

Channel concavity controls planform complexity of branching drainage networks

To explore the pattern formed by rivers as they crisscross the land, we developed a way to measure how these patterns vary, from straight to complex, winding paths. We discovered that a river’s degree of complexity depends on how the river slope changes downstream. Although this is strange (i.e., why would changes in slope affect twists of a river in map view?), we show that this dependency is almost inevitable and that the complexity could signify how arid the climate is or used to be.

Opinion: Challenges and needs of tropospheric chemical mechanism development

Chemical mechanisms describe the chemical processes in atmospheric models that are used to describe the changes in the atmospheric composition. Therefore, accurate chemical mechanisms are necessary to predict the evolution of air pollution and climate change. The article describes all steps that are needed to build chemical mechanisms and discusses the advances and needs of experimental and theoretical research activities needed to build reliable chemical mechanisms.

Exploring drought hazard, vulnerability, and related impacts on agriculture in Brandenburg

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-4237-2024
5 December 2024

Droughts are a threat to agricultural crops, but different factors influence how much damage occurs. This is important to know to create meaningful risk maps and to evaluate adaptation options. We investigate the years 2013–2022 in Brandenburg, Germany, and find in particular the soil quality and meteorological drought in June to be statistically related to the observed damage. Measurement of crop health from satellites is also related to soil quality and not necessarily to anomalous yields.

Weak liquid water path response in ship tracks

Ship emissions can form artificially brightened clouds, known as ship tracks, and provide us with an opportunity to investigate how aerosols interact with clouds. Previous studies that used ship tracks suggest that clouds can experience large increases in the amount of water (LWP) from aerosols. Here, we show that there is a bias in previous research and that, when we account for this bias, the LWP response to aerosols is much weaker than previously reported.

Modeling 2020 regulatory changes in international shipping emissions helps explain anomalous 2023 warming

On 1 January 2020, international shipping vessels were required to substantially reduce the amount of particulate they emit to improve air quality. In this work we demonstrate how this regulatory change contributed to the anomalous warming observed in recent months using climate model simulations that include such a change. Future policies should also perhaps consider their impact on climate, and climate modelers should promptly include those changes in future modeling efforts.

Cross-scale causal information flow from the El Niño–Southern Oscillation to precipitation in eastern China

The El Niño–Southern Oscillation (ENSO) is a gigantic natural orchestra playing with the temperature of Pacific waters and influencing air temperature and rainfall worldwide. Naturally, the “loudness” or amplitude of ENSO has effects on climate; however, consonance of its various tones, or phases of different ENSO oscillatory components, can exert causal effects on rainfall in some areas in China. In different regions, different aspects of ENSO dynamics can predict rainfall amounts.

Microbial response to deliquescence of nitrate-rich soils in the hyperarid Atacama Desert

We studied unique nitrate-rich soils in the hyperarid Atacama Desert that form brines at night under high relative humidity. Despite providing water for microorganisms, these soils exhibit extremely low microbial activity, indicating that the high nitrate levels inhibit microbial life. On the other hand, enriched organic matter indicates their potential preservation. This research helps to understand the limits of life in extreme environments and aids in the search for signs of life on Mars.

Microbial strong organic-ligand production is tightly coupled to iron in hydrothermal plumes

Hydrothermally derived iron can be transported kilometers away from deep-sea vents, representing a significant flux of vital micronutrients to the ocean. However, the mechanisms that support the stabilization of dissolved iron remain elusive. Using electrochemical, spectrometry, and genomic methods, we demonstrated that strong ligands exert an important control on iron in plumes, and high-affinity iron-binding siderophores were identified in several hydrothermal plume samples for the first time

Representation of the terrestrial carbon cycle in CMIP6

This study investigates present-day carbon cycle variables in CMIP5 and CMIP6 simulations. Overall, CMIP6 models perform better but also show many remaining biases. A significant improvement in the simulation of photosynthesis in models with a nitrogen cycle is found, with only small differences between emission- and concentration-based simulations. Thus, we recommend using emission-driven simulations in CMIP7 by default and including the nitrogen cycle in all future carbon cycle models.

Opinion: Beyond global means – novel space-based approaches to indirectly constrain the concentrations of and trends and variations in the tropospheric hydroxyl radical (OH)

Trace gases emitted to or formed within the atmosphere may be chemically or physically removed from the atmosphere. One trace gas, the hydroxyl radical (OH), is responsible for initiating the chemical removal of many trace gases, including some greenhouse gases. Despite its importance, scientists have not been able to adequately measure OH. In this opinion piece, we discuss promising new methods to indirectly constrain OH using satellite data of trace gases that control the abundance of OH.

Eddy covariance with slow-response greenhouse gas analysers on tall towers: bridging atmospheric and ecosystem greenhouse gas networks

This study presents direct flux measurements in tall towers using existing slow-response analysers and adding 3D sonic anemometers. This way, we can significantly improve greenhouse gas monitoring with little extra instrumental effort. Slow-response analysers may be used here as the relevant frequency ranges depend on measuring height. Tall towers offer a large footprint, amplifying spatial coverage. The presented concept is a valuable bridge between atmospheric and ecosystem communities.

Invited perspectives: safeguarding the usability and credibility of flood hazard and risk assessments

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-4015-2024
26 November 2024

Flood risk assessments help us decide how to reduce the risk of flooding. Since these assessments are based on probabilities, it is hard to check their accuracy by comparing them to past data. We suggest a new way to validate these assessments, making sure they are practical for real-life decisions. This approach looks at both the technical details and the real-world situations where decisions are made. We demonstrate its practicality by applying it to flood emergency planning.

X-BASE: the first terrestrial carbon and water flux products from an extended data-driven scaling framework, FLUXCOM-X

The movement of water, carbon, and energy from the Earth’s surface to the atmosphere, or flux, is an important process to understand because it impacts our lives. Here, we outline a method called FLUXCOM-X to estimate global water and CO2 fluxes based on direct measurements from sites around the world. We go on to demonstrate how these new estimates of net CO2 uptake/loss, gross CO2 uptake, total water evaporation, and transpiration from plants compare to previous and independent estimates.

Twenty-first century global glacier evolution under CMIP6 scenarios and the role of glacier-specific observations

Glaciers are major contributors to sea-level rise and act as key water resources. Here, we model the global evolution of glaciers under the latest generation of climate scenarios. We show that the type of observations used for model calibration can strongly affect the projections at the local scale. Our newly projected 21st century global mass loss is higher than the current community estimate as reported in the latest Intergovernmental Panel on Climate Change (IPCC) report.

How to measure the efficiency of bioenergy crops compared to forestation

Using a state-of-the-art land model, we find that bioenergy plants can store carbon more efficiently than forests over long periods in the soil, in geological reservoirs, or by substituting fossil-fuel-based energy. Planting forests is more suitable for reaching climate targets by 2050. The carbon removal potential depends also on local environmental conditions. These considerations have important implications for climate policy, spatial planning, nature conservation, and agriculture.

An overview of outdoor low-cost gas-phase air quality sensor deployments: current efforts, trends, and limitations

We reviewed 60 sensor networks and 17 related efforts (sensor review papers and data accessibility projects) to better understand the landscape of stationary low-cost gas-phase sensor networks deployed in outdoor environments worldwide. Gaps in monitoring efforts include the availability of gas-phase measurements compared to particulate matter (PM) and geographic coverage gaps (the Global South, rural areas). We conclude with a summary of cross-network unification and quality control efforts.

Testing floc settling velocity models in rivers and freshwater wetlands

Fine sediment grains in freshwater can cohere into faster-settling particles called flocs, but floc settling velocity theory has not been fully validated. Combining three data sources in novel ways in the Wax Lake Delta, we verified a semi-empirical model relying on turbulence and geochemical factors. For a physics-based model, we showed that the representative grain diameter within flocs relies on floc structure and that heterogeneous flow paths inside flocs increase floc settling velocity.

Tropospheric links to uncertainty in stratospheric subseasonal predictions

Strong variations in the strength of the stratospheric polar vortex can profoundly affect surface weather extremes; therefore, accurately predicting the stratosphere can improve surface weather forecasts. The research reveals how uncertainty in the stratosphere is linked to the troposphere. The findings suggest that refining models to better represent the identified sources and impact regions in the troposphere is likely to improve the prediction of the stratosphere and its surface impacts.

A three-stage model pipeline predicting regional avalanche danger in Switzerland (RAvaFcast v1.0.0): a decision-support tool for operational avalanche forecasting

By harnessing AI models, this work enables processing large amounts of data, including weather conditions, snowpack characteristics, and historical avalanche data, to predict human-like avalanche forecasts in Switzerland. Our proposed model can significantly assist avalanche forecasters in their decision-making process, thereby facilitating more efficient and accurate predictions crucial for ensuring safety in Switzerland’s avalanche-prone regions.

Exploring climate stabilisation at different global warming levels in ACCESS-ESM-1.5

Governments are targeting net-zero emissions later this century with the aim of limiting global warming in line with the Paris Agreement. However, few studies explore the long-term consequences of reaching net-zero emissions and the effects of a delay in reaching net-zero. We use the Australian Earth system model to examine climate evolution under net-zero emissions. We find substantial changes which differ regionally, including continued Southern Ocean warming and Antarctic sea ice reduction.