Using machine learning and beach cleanup data to explain litter quantities along the Dutch North Sea coast Ocean Science DOI 10.5194/os-18-269-2022 23 May 2022 A large amount of marine litter, such as plastics, is located on or around beaches. Both the total amount of this litter and its transport are poorly understood. We investigate this by training a machine learning model with data of clean-up efforts on Dutch beaches between 2014 and 2019, obtained by about 14 000 volunteers. We find that Dutch beaches contain up to 30 000 kg of litter, largely depending on tides, oceanic transport, and how exposed the beaches are. Read more
Magnetospheric response to solar wind forcing: ultra-low-frequency wave–particle interaction perspective Annales Geophysicae DOI 10.5194/angeo-40-121-2022 20 May 2022 Magnetospheric physics is in an extremely vibrant phase, with a number of ongoing and highly successful missions, e.g., Cluster, THEMIS, Van Allen Probes, and the MMS spacecraft, providing the most amazing observations and data sets. Since there are many fundamental and unsolved problems, in this paper I have addressed selected topics of ULF wave-charged particle interactions which encompass many special fields of radiation belt, ring current and plasmaspheric physics. Read more
Multilayer modelling of waves generated by explosive subaqueous volcanism Natural Hazards and Earth System Sciences DOI 10.5194/nhess-22-617-2022 18 May 2022 Volcanic eruptions can produce tsunamis through multiple mechanisms. We present validation cases for a numerical method used in simulating waves caused by submarine explosions: a laboratory flume experiment and waves generated by explosions at field scale. We then demonstrate the use of the scheme for simulating analogous volcanic eruptions, illustrating the resulting wavefield. We show that this scheme models such dispersive sources more proficiently than standard tsunami models. Read more
Future water temperature of rivers in Switzerland under climate change investigated with physics-based models Hydrology and Earth System Sciences DOI 10.5194/hess-26-1063-2022 16 May 2022 This study presents an extensive study of climate change impacts on river temperature in Switzerland. Results show that, even for low-emission scenarios, water temperature increase will lead to adverse effects for both ecosystems and socio-economic sectors throughout the 21st century. For high-emission scenarios, the effect will worsen. This study also shows that water seasonal warming will be different between the Alpine regions and the lowlands. Finally, efficiency of models is assessed. Read more
Using neural network ensembles to separate ocean biogeochemical and physical drivers of phytoplankton biogeography in Earth system models Geoscientific Model Development DOI 10.5194/gmd-15-1595-2022 13 May 2022 It can be challenging to understand why Earth system models (ESMs) produce specific results because one can arrive at the same result simply by changing the values of the parameters. In our paper, we demonstrate that it is possible to use machine learning to figure out how and why particular components of an ESM (such as biology or ocean circulations) affect the output. This work could be applied to observations to improve the accuracy of the formulations used in ESMs. Read more
Spatiotemporal patterns and drivers of terrestrial dissolved organic carbon (DOC) leaching into the European river network Earth System Dynamics DOI 10.5194/esd-13-393-2022 11 May 2022 Dissolved organic carbon (DOC) leaching from soils into river networks is an important component of the land carbon © budget, but its spatiotemporal variation is not yet fully constrained. We use a land surface model to simulate the present-day land C budget at the European scale, including leaching of DOC from the soil. We found average leaching of 14.3 Tg C yr-1 (0.6% of terrestrial net primary production) with seasonal variations. We determine runoff and temperature to be the main drivers. Read more
A regionally resolved inventory of High Mountain Asia surge-type glaciers, derived from a multi-factor remote sensing approach The Cryosphere DOI 10.5194/tc-16-603-2022 9 May 2022 Surging glaciers show cyclical changes in flow behaviour – between slow and fast flow – and can have drastic impacts on settlements in their vicinity. One of the clusters of surging glaciers worldwide is High Mountain Asia (HMA). We present an inventory of surging glaciers in HMA, identified from satellite imagery. We show that the number of surging glaciers was underestimated and that they represent 20% of the area covered by glaciers in HMA, before discussing new physics for glacier surges. Read more
Autonomous methane seep site monitoring offshore western Svalbard: hourly to seasonal variability and associated oceanographic parameters Ocean Science DOI 10.5194/os-18-233-2022 6 May 2022 Natural sources of atmospheric methane need to be better described and quantified. We present time series from ocean observatories monitoring two seabed methane seep sites in the Arctic. Methane concentration varied considerably on short timescales and seasonal scales. Seeps persisted throughout the year, with increased potential for atmospheric release in winter due to water mixing. The results highlight and constrain uncertainties in current methane estimates from seabed methane seepage. Read more
Acidification of the Nordic Seas Biogeosciences DOI 10.5194/bg-19-979-2022 4 May 2022 Ocean acidification, a direct consequence of the CO2 release by human activities, is a serious threat to marine ecosystems. In this study, we conduct a detailed investigation of the acidification of the Nordic Seas, from 1850 to 2100, by using a large set of samples taken during research cruises together with numerical model simulations. We estimate the effects of changes in different environmental factors on the rate of acidification and its potential effects on cold-water corals. Read more
Flash flood warnings in context: combining local knowledge and large-scale hydro-meteorological patterns Natural Hazards and Earth System Sciences DOI 10.5194/nhess-22-461-2022 2 May 2022 Local communities in northern Malawi have well-developed knowledge of the conditions leading to flash floods, spatially and temporally. Scientific analysis of catchment geomorphology and global reanalysis datasets corroborates this local knowledge, underlining the potential of these large-scale scientific datasets. Combining local knowledge with contemporary scientific datasets provides a common understanding of flash flood events, contributing to a more people-centred warning to flash floods. Read more
Abrupt climate changes and the astronomical theory: are they related? Climate of the Past DOI 10.5194/cp-18-249-2022 29 April 2022 The study of abrupt climate changes is a relatively new field of research that addresses paleoclimate variations that occur in intervals of tens to hundreds of years. Such timescales are much shorter than the tens to hundreds of thousands of years that the astronomical theory of climate addresses. We revisit several high-resolution proxy records of the past 3.2 Myr and show that the abrupt climate changes are nevertheless affected by the orbitally induced insolation changes. Read more
Evaluating the PurpleAir monitor as an aerosol light scattering instrument Atmospheric Measurement Techniques DOI 10.5194/amt-15-655-2022 27 April 2022 We show that the low-cost PurpleAir sensor can be characterized as a cell-reciprocal nephelometer. At two very different locations (Mauna Loa Observatory in Hawaii and the Table Mountain rural site in Colorado), the PurpleAir measurements are highly correlated with the submicrometer aerosol scattering coefficient measured by a research-grade integrating nephelometer. These results imply that, with care, PurpleAir data may be used to evaluate climate and air quality models. Read more
Late Neogene evolution of modern deep-dwelling plankton Biogeosciences DOI 10.5194/bg-19-743-2022 25 April 2022 Deep-living organisms are a major yet poorly known component of ocean biomass. Here we reconstruct the evolution of deep-living zooplankton and phytoplankton. Deep-dwelling zooplankton and phytoplankton did not occur 15 Myr ago, when the ocean was several degrees warmer than today. Deep-dwelling species first evolve around 7.5 Myr ago, following global climate cooling. Their evolution was driven by colder ocean temperatures allowing more food, oxygen, and light at depth. Read more
How many modes are needed to predict climate bifurcations? Lessons from an experiment Nonlinear Processes in Geophysics DOI 10.5194/npg-29-17-2022 22 April 2022 Present climate models discuss climate change but show no sign of bifurcation in the future. Is this because there is none or because they are in essence too simplified to be able to capture them? To get elements of an answer, we ran a laboratory experiment and discovered that the answer is not so simple. Read more
Vegetation change across the Drake Passage region linked to late Eocene cooling and glacial disturbance after the Eocene–Oligocene transition Climate of the Past DOI 10.5194/cp-18-209-2022 20 April 2022 New pollen and spore data from the Antarctic Peninsula region reveal temperate rainforests that changed and adapted in response to Eocene climatic cooling, roughly 35.5 Myr ago, and glacially related disturbance in the early Oligocene, approximately 33.5 Myr ago. The timing of these events indicates that the opening of ocean gateways alone did not trigger Antarctic glaciation, although ocean gateways may have played a role in climate cooling. Read more
Representativeness assessment of the pan-Arctic eddy covariance site network and optimized future enhancements Biogeosciences DOI 10.5194/bg-19-559-2022 18 April 2022 Thawing of Arctic permafrost soils could trigger the release of vast amounts of carbon to the atmosphere, thus enhancing climate change. Our study investigated how well the current network of eddy covariance sites to monitor greenhouse gas exchange at local scales captures pan-Arctic flux patterns. We identified large coverage gaps, e.g., in Siberia, but also demonstrated that a targeted addition of relatively few sites can significantly improve network performance. Read more
The Whole Antarctic Ocean Model (WAOM v1.0): development and evaluation Geoscientific Model Development DOI 10.5194/gmd-15-617-2022 15 April 2022 Here we present an improved model of the Antarctic continental shelf ocean and demonstrate that it is capable of reproducing present-day conditions. The improvements are fundamental and regard the inclusion of tides and ocean eddies. We conclude that the model is well suited to gain new insights into processes that are important for Antarctic ice sheet retreat and global ocean changes. The model will ultimately help to improve projections of sea level rise and climate change. Read more
Rhizodeposition efficiency of pearl millet genotypes assessed on a short growing period by carbon isotopes (δ13C and F14C) SOIL DOI 10.5194/soil-8-49-2022 13 April 2022 Unravelling relationships between plant rhizosheath, root exudation and soil C dynamic may bring interesting perspectives in breeding for sustainable agriculture. Using four pearl millet lines with contrasting rhizosheaths, we found that δ13C and F14C of root-adhering soil differed from those of bulk and control soil, indicating C exudation in the rhizosphere. This C exudation varied according to the genotype, and conceptual modelling performed with data showed a genotypic effect on the RPE. Read more
Impact of increased resolution on long-standing biases in HighResMIP-PRIMAVERA climate models Geoscientific Model Development DOI 10.5194/gmd-15-269-2022 11 April 2022 Climate models do not fully reproduce observations: they show differences (biases) in regional temperature, precipitation, or cloud cover. Reducing model biases is important to increase our confidence in their ability to reproduce present and future climate changes. Model realism is set by its resolution: the finer it is, the more physical processes and interactions it can resolve. We here show that increasing resolution of up to ~ 25 km can help reduce model biases but not remove them entirely. Read more
Improved representation of agricultural land use and crop management for large-scale hydrological impact simulation in Africa using SWAT+ Hydrology and Earth System Sciences DOI 10.5194/hess-26-71-2022 8 April 2022 We present an approach on how to incorporate crop phenology in a regional hydrological model using decision tables and global datasets of rain-fed and irrigated cropland with the associated cropping calendar and management practices. Results indicate improved temporal patterns of leaf area index (LAI) and evapotranspiration (ET) simulations in comparison with remote sensing data. In addition, the improvement of the cropping season also helps to improve soil erosion estimates in cultivated areas. Read more