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Influence of cohesive clay on wave–current ripple dynamics captured in a 3D phase diagram

The seabed can change its shape from flat to undulating, known as ripples; the change rate depends on whether the bed is composed of sticky mud. This study, based on experiments, shows a strong reduction in ripple size when the initial mud content is over 10.6 %. This could help geologists better interpret ancient sea conditions. We present a new model to predict ripple size by considering sticky mud. It should help engineers to describe the behaviour of the seabed when sticky mud is present.

Future water storage changes over the Mediterranean, Middle East, and North Africa in response to global warming and stratospheric aerosol intervention

Water storage (WS) plays a profound role in the lives of people in the Middle East and North Africa as well as Mediterranean climate “hot spots”. WS change by greenhouse gas (GHG) warming is simulated with and without stratospheric aerosol intervention (SAI). WS significantly increases in the Arabian Peninsula and decreases around the Mediterranean under GHG. While SAI partially ameliorates GHG impacts, projected WS increases in dry regions and decreases in wet areas relative to present climate.

GPROF V7 and beyond: assessment of current and potential future versions of the GPROF passive microwave precipitation retrievals against ground radar measurements over the continental US and the Pacific Ocean

The latest version of the GPROF retrieval algorithm that produces global precipitation estimates using observations from the Global Precipitation Measurement mission is validated against ground-based radars. The validation shows that the algorithm accurately estimates precipitation on scales ranging from continental to regional. In addition, we validate candidates for the next version of the algorithm and identify principal challenges for further improving space-borne rain measurements.

High-resolution spatial patterns and drivers of terrestrial ecosystem carbon dioxide, methane, and nitrous oxide fluxes in the tundra

Arctic greenhouse gas (GHG) fluxes of CO2, CH4, and N2O are important for climate feedbacks. We combined extensive in situ measurements and remote sensing data to develop machine-learning models to predict GHG fluxes at a 2 m resolution across a tundra landscape. The analysis revealed that the system was a net GHG sink and showed widespread CH4 uptake in upland vegetation types, almost surpassing the high wetland CH4 emissions at the landscape scale.

Toward generalized Milankovitch theory (GMT)

Despite significant progress in modelling Quaternary climate dynamics, a comprehensive theory of glacial cycles is still lacking. Here, using the results of model simulations and data analysis, I present a framework of the generalized Milankovitch theory (GMT), which further advances the concept proposed by Milutin Milankovitch over a century ago. The theory explains a number of facts which were not known during Milankovitch time’s, such as the 100 kyr periodicity of the late Quaternary.

The additionality problem of ocean alkalinity enhancement

Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.

Geomorphological and hydrological controls on sediment export in earthquake-affected catchments in the Nepal Himalaya

Using satellite images, we show that, unlike other examples of earthquake-affected rivers, the rivers of central Nepal experienced little increase in sedimentation following the 2015 Gorkha earthquake. Instead, a catastrophic flood occurred in 2021 that buried towns and agricultural land under up to 10 m of sediment. We show that intense storms remobilised glacial sediment from high elevations causing much a greater impact than flushing of earthquake-induced landslides.

Opinion: The importance of historical and paleoclimate aerosol radiative effects

Estimating past aerosol radiative effects and their uncertainties is an important topic in climate science. Aerosol radiative effects propagate into large uncertainties in estimates of how present and future climate evolves with changing greenhouse gas emissions. A deeper understanding of how aerosols interacted with the atmospheric energy budget under past climates is hindered in part by a lack of relevant paleo-observations and in part because less attention has been paid to the problem.

Quantifying particulate matter optical properties and flow rate in industrial stack plumes from the PRISMA hyperspectral imager

We propose analyzing the aerosol composition of plumes emitted by different industrial stacks using PRISMA satellite hyperspectral observations. Three industrial sites have been observed: a coal-fired power plant in South Africa, a steel plant in China, and gas flaring at an oil extraction site in Algeria. Aerosol optical thickness and particle radius are retrieved within the plumes. The mass flow rate of particulate matter is estimated in the plume using the integrated mass enhancement method.

Geochronological and geochemical effects of zircon chemical abrasion: insights from single-crystal stepwise dissolution experiments

Geochronology
DOI 10.5194/gchron-6-1-2024
29 December 2023

Acid leaching is used to remove radiation-damaged portions of zircon crystals prior to U–Pb dating to improve the accuracy of datasets. We test how the temperature and duration of acid leaching affect geochronological and geochemical outcomes. We build a framework that relates radiation damage, zircon solubility, and Pb loss.

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