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Using machine learning and beach cleanup data to explain litter quantities along the Dutch North Sea coast

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.

Magnetospheric response to solar wind forcing: ultra-low-frequency wave–particle interaction perspective

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.

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.

Future water temperature of rivers in Switzerland under climate change investigated with physics-based models

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.

Using neural network ensembles to separate ocean biogeochemical and physical drivers of phytoplankton biogeography in Earth system models

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.

Spatiotemporal patterns and drivers of terrestrial dissolved organic carbon (DOC) leaching into the European river network

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.

A regionally resolved inventory of High Mountain Asia surge-type glaciers, derived from a multi-factor remote sensing approach

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.

Autonomous methane seep site monitoring offshore western Svalbard: hourly to seasonal variability and associated oceanographic parameters

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.

Acidification of the Nordic Seas

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.

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.

Abrupt climate changes and the astronomical theory: are they related?

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.

Evaluating the PurpleAir monitor as an aerosol light scattering instrument

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.

Late Neogene evolution of modern deep-dwelling plankton

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.

How many modes are needed to predict climate bifurcations? Lessons from an experiment

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.

Vegetation change across the Drake Passage region linked to late Eocene cooling and glacial disturbance after the Eocene–Oligocene transition

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.

Representativeness assessment of the pan-Arctic eddy covariance site network and optimized future enhancements

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.

The Whole Antarctic Ocean Model (WAOM v1.0): development and evaluation

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.

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.

Impact of increased resolution on long-standing biases in HighResMIP-PRIMAVERA climate models

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.

Improved representation of agricultural land use and crop management for large-scale hydrological impact simulation in Africa using SWAT+

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.

Arctic sea level variability from high-resolution model simulations and implications for the Arctic observing system

This study explores the Arctic sea level variability depending on different timescales and the relation to temperature, salinity and mass changes, identifying key parameters and regions that need to be observed co-ordinately. The decadal sea level variability reflects salinity changes. But it can only reflect salinity change at periods of greater than 1 year, highlighting the requirement for enhancing in situ hydrographic observations and complicated interpolation methods.

Dependency of the impacts of geoengineering on the stratospheric sulfur injection strategy – Part 1: Intercomparison of modal and sectional aerosol modules

The use of different spatio-temporal sulfur injection strategies with different magnitudes to create an artificial reflective aerosol layer to cool the climate is studied using sectional and modal aerosol schemes in a climate model. There are significant differences in the results depending on the aerosol microphysical module used. Different spatio-temporal injection strategies have a significant impact on the magnitude and zonal distribution of radiative forcing and atmospheric dynamics.

Not all biodiversity rich spots are climate refugia

Biodiversity is under threat from the effects of global warming, and assessing the effects of climate change on areas of high species richness is of prime importance to conservation. Terrestrial and freshwater rich spots have been and will be less affected by climate change than other areas. However, marine rich spots of biodiversity are expected to experience more pronounced warming.

Balanced estimate and uncertainty assessment of European climate change using the large EURO-CORDEX regional climate model ensemble

This research paper proposes an assessment of mean climate change responses and related uncertainties over Europe for mean seasonal temperature and total seasonal precipitation. An advanced statistical approach is applied to a large ensemble of 87 high-resolution EURO-CORDEX projections. For the first time, we provide a comprehensive estimation of the relative contribution of GCMs and RCMs, RCP scenarios, and internal variability to the total variance of a very large ensemble.

The ESA MIPAS/Envisat level2-v8 dataset: 10 years of measurements retrieved with ORM v8.22

The level-2 v8 database from the measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), aboard the European Space Agency Envisat satellite, containing atmospheric fields of pressure, temperature, and volume mixing ratio of 21 trace gases, is described in this paper. The database covers all the measurements acquired by MIPAS (from July 2002 to April 2012). The number of species included makes it of particular importance for the studies of stratospheric chemistry.

A simple model of ozone–temperature coupling in the tropical lower stratosphere

Balloon and satellite observations show strong coupling between large-scale ozone and temperature fields in the tropical lower stratosphere, spanning timescales of days to years. We present a simple interpretation of this behaviour based on an idealized model of transport by the tropical stratospheric circulation, and good quantitative agreement with observations demonstrates that this is a useful simplification. The results provide simple understanding of observed atmospheric behaviour.

Secondary ice production during the break-up of freezing water drops on impact with ice particles

Secondary ice production (SIP) plays an important role in ice formation within mixed-phase clouds. We present a laboratory investigation of a potentially new SIP mechanism involving the collisions of supercooled water drops with ice particles. At impact, the supercooled water drop fragments form smaller secondary drops. Approximately 30 % of the secondary drops formed during the retraction phase of the supercooled water drop impact freeze over a temperature range of -4 °C to -12 °C.

Deep oceanic submarine fieldwork with undergraduate students: an immersive experience with the Minerve software

We use the Minerve virtual reality software to bring undergraduate students to an unusual field trip at 1200 m below sea level in the Lesser Antilles area. This region is located above an active subduction zone responsible for intense volcanic and seismic activity. In particular, we focus on the Roseau submarine fault that ruptured during the Mw 6.3 Les Saintes earthquake and presented a fresh scarp that the students can analyse and map in VR. They compile their results in a GIS project.

Impact of the melt–albedo feedback on the future evolution of the Greenland Ice Sheet with PISM-dEBM-simple

With the increasing melt of the Greenland Ice Sheet, which contributes to sea level rise, the surface of the ice darkens. The dark surfaces absorb more radiation and thus experience increased melt, resulting in the melt–albedo feedback. Using a simple surface melt model, we estimate that this positive feedback contributes to an additional 60 % ice loss in a high-warming scenario and additional 90 % ice loss for moderate warming. Albedo changes are important for Greenland’s future ice loss.

The blue suns of 1831: was the eruption of Ferdinandea, near Sicily, one of the largest volcanic climate forcing events of the nineteenth century?

An unidentified eruption in 1831 was one of the largest volcanic climate forcing events of the nineteenth century. We use reported observations of a blue sun to reconstruct the transport of an aerosol plume from that eruption and, hence, identify it as the 1831 eruption of Ferdinandea, near Sicily. We propose that, although it was only a modest eruption, its volcanic plume was enriched with sulphur from sedimentary deposits and that meteorological conditions helped it reach the stratosphere.

Brief communication: A roadmap towards credible projections of ice sheet contribution to sea level

Estimating how much ice loss from Greenland and Antarctica will contribute to sea level rise is of critical societal importance. However, our analysis shows that recent efforts are not trustworthy because the models fail at reproducing contemporary ice melt. Here we present a roadmap towards making more credible estimates of ice sheet melt.

Options to correct local turbulent flux measurements for large-scale fluxes using an approach based on large-eddy simulation

Turbulent flux measurements suffer from a general systematic underestimation. One reason for this bias is non-local transport by large-scale circulations. A recently developed model for this additional transport of sensible and latent energy is evaluated for three different test sites. Different options on how to apply this correction are presented, and the results are evaluated against independent measurements.

Dynamics of variable dusk–dawn flow associated with magnetotail current sheet flapping

The sun’s magnetic field is carried across space by the solar wind – a hot plasma “stream” of ions and electrons – forming the interplanetary magnetic field (IMF). The IMF can introduce asymmetries in the Earth’s magnetic field, giving plasma flowing within it a direction dependent on IMF orientation. Electric currents in near-Earth space can also influence these plasma flows. We investigate these two competing mechanisms and find that the currents can prevent the IMF from controlling the flow.

Identifying community values related to heat: recommendations for forecast and health risk communication

This paper presents an analysis of public responses to U.S. National Weather Service heat-related Facebook posts for the Phoenix (Arizona) County Warning Area to identify community norms that may present challenges to the effectiveness of heat risk communication. Findings suggest that local audiences tend to view heat as normal and the ability to withstand heat as a marker of community identity. Recommendations are provided for harnessing those norms to promote positive behavioural change.

Modelling the volcanic ash plume from Eyjafjallajökull eruption (May 2010) over Europe: evaluation of the benefit of source term improvements and of the assimilation of aerosol measurements

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-21-3731-2021
4 March 2022

Volcanic eruptions that spread out ash over large areas, like Eyjafjallajökull in 2010, may have huge economic consequences due to flight cancellations. In this article, we demonstrate the benefits of source term improvement and of data assimilation for quantifying volcanic ash concentrations. The work, which was supported by the EUNADICS-AV project, is the first one, to our knowledge, that demonstrates the benefit of the assimilation of ground-based lidar data over Europe during an eruption.

Ubiquity of human-induced changes in climate variability

A large ensemble of simulations with 100 members has been conducted with the state-of-the-art CESM2 Earth system model, using historical and SSP3-7.0 forcing. Our main finding is that there are significant changes in the variance of the Earth system in response to anthropogenic forcing, with these changes spanning a broad range of variables important to impacts for human populations and ecosystems.

SELF v1.0: a minimal physical model for predicting time of freeze-up in lakes

The time when lakes freeze varies considerably from year to year. A common way to predict it is to use negative degree days, i.e., the sum of air temperatures below 0°C, a proxy for the heat lost to the atmosphere. Here, we show that this is insufficient as the mixing of the surface layer induced by wind tends to delay the formation of ice. To do so, we developed a minimal model based on a simplified energy balance, which can be used both for large-scale analyses and short-term predictions.

Annual exposure to polycyclic aromatic hydrocarbons in urban environments linked to wintertime wood-burning episodes

We analyse observations from year-long measurements at Athens, Greece. Nighttime wintertime PAH levels are 4 times higher than daytime, and wintertime values are 15 times higher than summertime. Biomass burning aerosol during wintertime pollution events is responsible for these significant wintertime enhancements and accounts for 43 % of the population exposure to PAH carcinogenic risk. Biomass burning poses additional health risks beyond those associated with the high PM levels that develop.

Assessing the dependence structure between oceanographic, fluvial, and pluvial flooding drivers along the United States coastline

We analyse dependences between different flooding drivers around the USA coastline, where the Gulf of Mexico and the southeastern and southwestern coasts are regions of high dependence between flooding drivers. Dependence is higher during the tropical season in the Gulf and at some locations on the East Coast but higher during the extratropical season on the West Coast. The analysis gives new insights on locations, driver combinations, and the time of the year when compound flooding is likely.

Extreme metrics from large ensembles: investigating the effects of ensemble size on their estimates

We address the question of how large an initial condition ensemble of climate model simulations should be if we are concerned with accurately projecting future changes in temperature and precipitation extremes. We find that for most cases (and both models considered), an ensemble of 20-25 members is sufficient for many extreme metrics, spatial scales and time horizons. This may leave computational resources to tackle other uncertainties in climate model simulations with our ensembles.

Tracking aerosols and SO2 clouds from the Raikoke eruption: 3D view from satellite observations

The 21 June 2019 eruption of the Raikoke volcano produced significant amounts of volcanic aerosols (sulfate and ash) and sulfur dioxide (SO2) gas that penetrated into the lower stratosphere. We showed that the amount of SO2 decreases with a characteristic period of 8–18 d and the peak of sulfate aerosol lags the initial peak of SO2 by 1.5 months. We also examined the dynamics of an unusual stratospheric coherent circular cloud of SO2 and aerosol observed from 18 July to 22 September 2019.

Rectified tidal transport in Lofoten–Vesterålen, northern Norway

Ocean Science
DOI 10.5194/os-17-1753-2021
16 February 2022

Non-linear tidal dynamics can produce prominent time-mean transport in coastal regions where strong tidal currents interact with topography. We investigate tidal-induced transport using a tidally driven ocean model for Lofoten-Vesterålen in northern Norway and find that both tidal pumping and tidal rectification can play an important role for time-mean transport in the region. The study emphasizes the importance of non-linear tidal dynamics for time-mean transport in complex coastal regions.

Assessment of the ParFlow–CLM CONUS 1.0 integrated hydrologic model: evaluation of hyper-resolution water balance components across the contiguous United States

Modeling the hydrologic cycle at high resolution and at large spatial scales is an incredible opportunity and challenge for hydrologists. In this paper, we present the results of a high-resolution hydrologic simulation configured over the contiguous United States. We discuss simulated water fluxes through groundwater, soil, plants, and over land, and we compare model results to in situ observations and satellite products in order to build confidence and guide future model development.

Spatiotemporal distribution of seasonal snow water equivalent in High Mountain Asia from an 18-year Landsat–MODIS era snow reanalysis dataset

We examined the spatiotemporal distribution of stored water in the seasonal snowpack over High Mountain Asia, based on a new snow reanalysis dataset. The dataset was derived utilizing satellite-observed snow information, which spans across 18 water years, at a high spatial (~ 500 m) and temporal (daily) resolution. Snow mass and snow storage distribution over space and time are analysed in this paper, which brings new insights into understanding the snowpack variability over this region.

Orogenic lithosphere and slabs in the greater Alpine area – interpretations based on teleseismic P-wave tomography

Solid Earth
DOI 10.5194/se-12-2633-2021
9 February 2022

New images from the multi-national AlpArray experiment illuminate the Alps from below. They indicate thick European mantle descending beneath the Alps and forming blobs that are mostly detached from the Alps above. In contrast, the Adriatic mantle in the Alps is much thinner. This difference helps explain the rugged mountains and the abundance of subducted and exhumed units at the core of the Alps. The blobs are stretched remnants of old ocean and its margins that reach down to at least 410 km.

Seasonal evolution of Antarctic supraglacial lakes in 2015–2021 and links to environmental controls

We provide novel insight into the temporal evolution of supraglacial lakes across six major Antarctic ice shelves in 2015–2021. For Antarctic Peninsula ice shelves, we observe extensive meltwater ponding during the 2019–2020 and 2020–2021 summers. Over East Antarctica, lakes were widespread during 2016–2019 and at a minimum in 2020–2021. We investigate environmental controls, revealing lake ponding to be coupled to atmospheric modes, the near-surface climate and the local glaciological setting.

Future summer warming pattern under climate change is affected by lapse-rate changes

In a warmer future climate, climate simulations predict that some land areas will experience excessive warming during summer. We show that the excessive summer warming is related to the vertical distribution of warming within the atmosphere. In regions characterized by excessive warming, much of the warming occurs close to the surface. In other regions, most of the warming is redistributed to higher levels in the atmosphere, which weakens the surface warming.

Two decades of dynamic change and progressive destabilization on the Thwaites Eastern Ice Shelf

We present a 20-year, satellite-based record of velocity and thickness change on the Thwaites Eastern Ice Shelf (TEIS), the largest remaining floating extension of Thwaites Glacier (TG). TG holds the single greatest control on sea-level rise over the next few centuries, so it is important to understand changes on the TEIS, which controls much of TG’s flow into the ocean. Our results suggest that the TEIS is progressively destabilizing and is likely to disintegrate over the next few decades.

Accumulation of legacy fallout radionuclides in cryoconite on Isfallsglaciären (Arctic Sweden) and their downstream spatial distribution

Our paper presents results of sample collection and subsequent geochemical analyses from the glaciated Isfallsglaciären catchment in Arctic Sweden. The data suggest that material found on the surface of glaciers, “cryoconite”, is very efficient at accumulating products of nuclear fallout transported in the atmosphere following events such as the Chernobyl disaster. We investigate how this compares with samples in the downstream environment and consider potential environmental implications.

A sulfur dioxide Covariance-Based Retrieval Algorithm (COBRA): application to TROPOMI reveals new emission sources

We present a new algorithm to retrieve sulfur dioxide from space UV measurements. We apply the technique to high-resolution TROPOMI measurements and demonstrate the high sensitivity of the approach to weak SO2 emissions worldwide with an unprecedented limit of detection of 8 kt yr-1. This result has broad implications for atmospheric science studies dealing with improving emission inventories and identifying and quantifying missing sources, in the context of air quality and climate.