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European Geosciences Union

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1743 items found

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Does high-latitude ionospheric electrodynamics exhibit hemispheric mirror symmetry?

In studies of the Earth’s ionosphere, a hot topic is how to estimate ionospheric conductivity. This is hard to do for a variety of reasons that mostly amount to a lack of measurements. In this study we use satellite measurements to estimate electromagnetic work and ionospheric conductances in both hemispheres. We identify where our model estimates are inconsistent with laws of physics, which partially solves a previous problem with unrealistic predictions of ionospheric conductances.

Extensive coverage of ultrathin tropical tropopause layer cirrus clouds revealed by balloon-borne lidar observations

Upper tropical clouds have a strong impact on Earth’s climate but are challenging to observe. We report the first long-duration observations of tropical clouds from lidars flying on board stratospheric balloons. Comparisons with spaceborne observations reveal the enhanced sensitivity of balloon-borne lidar to optically thin cirrus. These clouds, which have a significant coverage and lie in the uppermost troposphere, are linked with the dehydration of air masses on their way to the stratosphere.

A major midlatitude hurricane in the Little Ice Age

A Little Ice Age (LIA) hurricane was characterized using key storm intensity metrics from historical naval records. Its unusual intensity was driven by a higher temperature gradient between continental and coastal atmospheric circulation that drove intense midlatitude extratropical transition. Quantitative attributes embedded in historical records allow multidisciplinary research to extend our understanding of climate processes through the historical period.

Does a convection-permitting regional climate model bring new perspectives on the projection of Mediterranean floods?

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-24-1163-2024
20 May 2024

High-resolution convection-permitting climate models (CPMs) are now available to better simulate rainstorm events leading to flash floods. In this study, two hydrological models are compared to simulate floods in a Mediterranean basin, showing a better ability of the CPM to reproduce flood peaks compared to coarser-resolution climate models. Future projections are also different, with a projected increase for the most severe floods and a potential decrease for the most frequent events.

A network approach for multiscale catchment classification using traits

We present a new method based on network science for unsupervised classification of large datasets and apply it to classify 9067 US catchments and 274 biophysical traits at multiple scales. We find that our trait-based approach produces catchment classes with distinct streamflow behavior and that spatial patterns emerge amongst pristine and human-impacted catchments. This method can be widely used beyond hydrology to identify patterns, reduce trait redundancy, and select representative sites.

Unraveling biogeographical patterns and environmental drivers of soil fungal diversity at the French national scale

SOIL
DOI 10.5194/soil-10-251-2024
15 May 2024

The fungal kingdom has been diversifying for more than 800 million years by colonizing a large number of habitats on Earth. Based on a unique dataset (18S rDNA meta-barcoding), we described the spatial distribution of fungal diversity at the scale of France and the environmental drivers by tackling biogeographical patterns. We also explored the fungal network interactions across land uses and climate types.

NEWTS1.0: Numerical model of coastal Erosion by Waves and Transgressive Scarps

Models of rocky coastal erosion help us understand the controls on coastal morphology and evolution. In this paper, we present a simplified model of coastline erosion driven by either uniform erosion where coastline erosion is constant or wave-driven erosion where coastline erosion is a function of the wave power. This model can be used to evaluate how coastline changes reflect climate, sea-level history, material properties, and the relative influence of different erosional processes.

The perfect storm? Co-occurring climate extremes in East Africa

Climate change affects the interaction, dependence, and joint occurrence of climate extremes. Here we investigate the joint occurrence of pairs of river floods, droughts, heatwaves, crop failures, wildfires, and tropical cyclones in East Africa under past and future climate conditions. Our results show that, across all future warming scenarios, the frequency and spatial extent of these co-occurring extremes will increase in this region, particularly in areas close to the Nile and Congo rivers.

Resemblance of the global depth distribution of internal-tide generation and cold-water coral occurrences

Cold-water corals (CWCs) and tidal waves in the interior of the ocean have been connected in case studies. We demonstrate this connection globally using hydrodynamic simulations and a CWC database. Internal-tide generation shows a similar depth pattern with slope steepness and latitude as CWCs. Our results suggest that internal-tide generation can be a useful predictor of CWC habitat and that current CWC habitats might change following climate-change-related shoaling of internal-tide generation.

Evaluating the impact of climate communication activities by scientists: what is known and necessary?

Climate scientists are urged to communicate climate science; there is very little evidence about what types of communication work well for which audiences. We have performed a systematic literature review to analyze what is known about the efficacy of climate communication by scientists. While we have found more than 60 articles in the last 10 years about climate communication activities by scientists, only 7 of these included some form of evaluation of the impact of the activity.

Dependency of the impacts of geoengineering on the stratospheric sulfur injection strategy – Part 2: How changes in the hydrological cycle depend on the injection rate and model used

This study is the second in a two-part series in which we explore the dependency of the impacts of stratospheric sulfur injections on both the model employed and the strategy of injection utilized. The study uncovers uncertainties associated with these techniques to cool climate, highlighting how the simulated climate impacts are dependent on both the selected model and the magnitude of the injections. We also show that estimating precipitation impacts of aerosol injection is a complex task.

The six rights of how and when to test for soil C saturation

SOIL
DOI 10.5194/soil-10-275-2024
29 April 2024

Soil C saturation has been tested in several recent studies and led to a debate about its existence. We argue that, to test C saturation, one should pay attention to six fundamental principles: the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find support for a maximum of C stabilized by minerals and thus soil C saturation.

Interpretability of negative latent heat fluxes from eddy covariance measurements in dry conditions

Porous materials are known to reversibly trap water from the air, even at low humidity. However, this behavior is poorly understood for soils. In this analysis, we test whether eddy covariance is able to measure the so-called adsorption of atmospheric water vapor by soils. We find that this flux occurs frequently during dry nights in a Mediterranean ecosystem, while EC detects downwardly directed vapor fluxes. These results can help to map moisture uptake globally.

Carbon budget concept and its deviation through the pulse response lens

The carbon budget approach is based on a close linear relationship between the global temperature and cumulative emissions. This article reinterprets the carbon budget approach through the lens of the temperature response to an emission pulse in the role of a Green’s function, or as a generalization of TCRE. It shows that inspecting the simple model’s pulse response allows for a prediction of deviations for any possible emission scenario and derivation of a nonlinear carbon budget equation.

Quantitative imaging of carbon dioxide plumes using a ground-based shortwave infrared spectral camera

Imaging carbon dioxide (CO2) plumes of anthropogenic sources from planes and satellites has proven valuable for detecting emitters and monitoring climate mitigation efforts. We present the first images of CO2 plumes taken with a ground-based spectral camera, observing a coal-fired power plant as a validation target. We develop a technique to find the source emission strength with an hourly resolution, which reasonably agrees with the expected emissions under favorable conditions.

HydroFATE (v1): a high-resolution contaminant fate model for the global river system

Treated and untreated wastewaters are sources of contaminants of emerging concern. HydroFATE, a new global model, estimates their concentrations in surface waters, identifying streams that are most at risk and guiding monitoring/mitigation efforts to safeguard aquatic ecosystems and human health. Model predictions were validated against field measurements of the antibiotic sulfamethoxazole, with predicted concentrations exceeding ecological thresholds in more than 400 000 km of rivers worldwide.

Rates of palaeoecological change can inform ecosystem restoration

Rate-of-change records based on compositional data are ambiguous as they may rise irrespective of the underlying trajectory of ecosystems. We emphasize the importance of characterizing both the direction and the rate of palaeoecological changes in terms of key features of ecosystems rather than solely on community composition. Past accelerations of community transformation may document the potential of ecosystems to rapidly recover important ecological attributes and functions.

Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates

This study uses airborne radar data and satellite imagery to map mountainous topography hidden beneath the Greenland Ice Sheet. We find that the landscape records the former extent and configuration of ice masses that were restricted to areas of high topography. Computer models of ice flow indicate that valley glaciers eroded this landscape millions of years ago when local air temperatures were at least 4 °C higher than today and Greenland’s ice volume was < 10 % of that of the modern ice sheet.

Minimizing the effects of Pb loss in detrital and igneous U–Pb zircon geochronology by CA-LA-ICP-MS

Chemical abrasion (CA) is a technique that reduces or eliminates the effects of Pb loss in zircon U–Pb geochronology. However, CA has yet to be applied to large-n detrital zircon (DZ) analyses. We show that CA does not negatively impact or systematically bias U–Pb dates, improves the resolution of age populations defined by 206Pb/238U dates, and increases the percentage of concordant analyses in age populations defined by 207Pb/206Pb dates.

Extreme melting at Greenland’s largest floating ice tongue

The 79° North Glacier in Greenland has experienced significant changes over the last decades. Due to extreme melt rates, the ice has thinned significantly in the vicinity of the grounding line, where a large subglacial channel has formed since 2010. We attribute these changes to warm ocean currents and increased subglacial discharge from surface melt. However, basal melting has decreased since 2018, indicating colder water inflow into the cavity below the glacier.