Aerosol–cloud interactions: the representation of heterogeneous ice activation in cloud models Atmospheric Chemistry and Physics DOI 10.5194/acp-21-15213-2021 20 December 2021 Aerosol–cloud interactions play an important role in climate change. Simulations of the competition between homogeneous solution droplet freezing and heterogeneous ice nucleation can be compromised by the misapplication of ice-active particle fractions frequently derived from laboratory measurements or parametrizations. Our study frames the problem and establishes a solution that is easy to implement in cloud models. Read more
Deep ice as a geochemical reactor: insights from iron speciation and mineralogy of dust in the Talos Dome ice core (East Antarctica) The Cryosphere DOI 10.5194/tc-15-4807-2021 17 December 2021 As scientists are pushing efforts to recover deep ice cores to extend paleoclimatic reconstructions, it is now essential to explore deep ice. The latter was considered a relatively stable environment, but this view is changing. This study shows that the conditions of deep ice promote the interaction between soluble and insoluble impurities, favoring complex geochemical reactions that lead to the englacial dissolution and precipitation of specific minerals present in atmospheric mineral dust. Read more
Ambient aerosol properties in the remote atmosphere from global-scale in situ measurements Atmospheric Chemistry and Physics DOI 10.5194/acp-21-15023-2021 15 December 2021 The Atmospheric Tomography Mission was an airborne study that mapped the chemical composition of the remote atmosphere. From this, we developed a comprehensive description of aerosol properties that provides a unique, global-scale dataset against which models can be compared. The data show the polluted nature of the remote atmosphere in the Northern Hemisphere and quantify the contributions of sea salt, dust, soot, biomass burning particles, and pollution particles to the haziness of the sky. Read more
Statistical characteristics of extreme daily precipitation during 1501 BCE–1849 CE in the Community Earth System Model Climate of the Past DOI 10.5194/cp-17-2031-2021 13 December 2021 To understand the natural characteristics and future changes of the global extreme daily precipitation, it is necessary to explore the long-term characteristics of extreme daily precipitation. Here, we used climate simulations to analyze the characteristics and long-term changes of extreme precipitation during the past 3351 years. Our findings indicate that extreme precipitation in the past is associated with internal climate variability and regional surface temperatures. Read more
Modeling the marine chromium cycle: new constraints on global-scale processes Biogeosciences DOI 10.5194/bg-18-5447-2021 10 December 2021 Chromium (Cr) is a redox-sensitive element that holds promise as a tracer of ocean oxygenation and biological activity. We here implemented the oxidation states Cr(III) and Cr(VI) in the Bern3D model to investigate the processes that shape the global Cr distribution. We find a Cr ocean residence time of 5–8 kyr and that the benthic source dominates the tracer budget. Further, regional model–data mismatches suggest strong Cr removal in oxygen minimum zones and a spatially variable benthic source. Read more
Interannual variability in contributions of the Equatorial Undercurrent (EUC) to Peruvian upwelling source water Ocean Science DOI 10.5194/os-17-1385-2021 8 December 2021 The Equatorial Undercurrent (EUC) is a key influence on upwelling of nutrient-rich waters associated ecosystems off Peru. To quantify this influence, we backtrack upwelling waters in a computer model of ocean currents, annually, over 1989–2007. The EUC influence varies from year to year, dominating in warm El Niño years, when the EUC extends much closer to the Peruvian coast. In other years, more “local” upwelling is associated with coastal winds, coincident with major key population shifts. EUC) to Peruvian upwelling source water">Read more
An ensemble of state-of-the-art ash dispersion models: towards probabilistic forecasts to increase the resilience of air traffic against volcanic eruptions Natural Hazards and Earth System Sciences DOI 10.5194/nhess-21-2973-2021 6 December 2021 Past volcanic eruptions that spread out ash over large areas, like Eyjafjallajökull in 2010, forced the cancellation of thousands of flights and had huge economic consequences. In this article, an international team in the H2020 EU-funded EUNADICS-AV project has designed a probabilistic model approach to quantify ash concentrations. This approach is evaluated against measurements, and its potential use to mitigate the impact of future large-scale eruptions is discussed. Read more
Drifting dynamics of the bluebottle (Physalia physalis) Ocean Science DOI 10.5194/os-17-1341-2021 3 December 2021 The bluebottle (Physalia physalis), or Portuguese man o’ war, is well known for the painful stings caused by its tentacles. Its drifting dynamics have not been widely explored, with previous studies using simple assumptions to calculate its drift. Considering similarities with a sailboat, we present a new theoretical model for the drifting speed and course of the bluebottle in different wind and ocean conditions, providing new insights into the parameterization of its complex drifting dynamics. Read more
Sand mining far outpaces natural supply in a large alluvial river Earth Surface Dynamics DOI 10.5194/esurf-9-1323-2021 1 December 2021 Unsustainable sand mining poses a threat to the stability of river channels. We use satellite imagery to estimate volumes of material removed from the Mekong River, Cambodia, over the period 2016–2020. We demonstrate that current rates of extraction now exceed previous estimates for the entire Mekong Basin and significantly exceed the volume of sand naturally transported by the river. Our work highlights the importance of satellite imagery in monitoring sand mining activity over large areas. Read more
Dating folding beyond folding, from layer-parallel shortening to fold tightening, using mesostructures: lessons from the Apennines, Pyrenees, and Rocky Mountains Solid Earth DOI 10.5194/se-12-2145-2021 29 November 2021 This paper aims to illustrate how the timing and duration of contractional deformation associated with folding in orogenic forelands can be constrained by the dating of brittle mesostructures observed in folded strata. The study combines new and already published absolute ages of fractures to provide, for the first time, an educated discussion about the factors controlling the duration of the sequence of deformation encompassing layer-parallel shortening, fold growth, and late fold tightening. Read more
