bluuebunny/crossref_metadata_2025 huggingface dataset:
Probabilistic estimation of glacier surface elevation changes from DEM differentiation: a Bayesian method for outlier filtering, gap filling and uncertainty estimation with examples from High Mountain Asia
Authors: Guillet Gregoire , Bolch Tobias
Published: March 2022

Various interdisciplinary studies have shown substantial discrepancies between modeled and remotely sensed glacier surface elevation change.It is therefore crucial to better understand and quantify uncertainties associated to both methods. We design a probabilistic framework with the aim to filter outliers, fill data voids and estimate uncertainties in glacier surface elevation changes computed from Digital Elevation Model (DEM) differentiation. The technique is based on a Bayesian formulation of the DEM difference problem and specifically targets surging and debris-covered glaciers, both at glacier and regional scales. We first define a set of physically admissible surface elevation changes as an elevation-dependent probability density function.

In a second step, terrain roughness is defined as the main descriptor for DEM uncertainty. Each surface elevation change pixel is a probability distribution. We present validation experiments in High Mountain Asia and show that the model produces results consistent with conventional DEM differencing, while avoiding the caveats of already existing methods. We further demonstrate that accounting for unstable glacier dynamics is crucial for accurate outlier filtering and robust uncertainty estimation. The technique can be applied to other types of remotely sensed glacier quantities (surface velocity etc.) and would provide more reliable characterization of uncertainty associated with changes in glacier mass and dynamics.
A possible surface rupture of the 1756 Düren earthquake (Lower Rhine Graben)
Authors: Steinritz Vanessa , Hürtgen Jochen , Reicherter Klaus
Published: March 2022

Strong and rare or infrequent intraplate quakes in densely populated areas pose a significant risk to humans, infrastructure, and the environment. The Lower Rhine Graben is tectonically one of the most active zones in central Europe, and it is part of the European Cenozoic rift system. The destructive 1756 CE Düren Earthquake (Mw 6.4±0.3; located in western Germany), or the  1992 CE Roermond Earthquake (Mw 5.9; located in eastern Netherlands), both caused by normal faults of the Lower Rhine Graben, inflicted tremendous damage and demonstrate the need of hazard assessments and prevention in this highly industrialized area. Therefore, mapping and detecting of the traces, historical activity and kinematics of faults and related fault systems, is of high importance for hazard assessment of critical infrastructure   (i.e. pipelines, highways, lifelines) and cities in the Dutch, Belgian and German border region.

The 1756 CE Düren earthquake was one of the most destructive ones in the area, and in entire Central Europe, the observed damage (landslides, sackungen) and magnitude suggest a surface rupturing event. The causative fault is still under debate, also epicentral area and hypocentral depth remain enigmatic although different studies investaged several faults in the area, e.g. the normal Rurrand Fault or the Schafberg Fault. The Rurrand Fault does not exhibit seismic surface rupturing events younger than 2.3 ka, whereas the Schafberg Fault is much too short to produce a M > 6 event and trenching failed.

Trenching at the Birkesdorfer Sprung (or Fault), a NW-SE trending normal fault with a minimum length of c. 9 km, revealed a set of SW dipping normal faults associated with colluvial wedges and unconformities. Geophysical ground survey methods (GPR and ERT) as well as GIS-based morphotectonic analyses identified a long fault trace. Radiocarbon (14C) charcoal dating of displaced colluvial deposits revealed very young ages of c. 240 y BP and evidence for a second event older than c. 3.6 ky BP, the latter has been already described. However, this older event can be bracketed here much better in between 9.1 ± 1.5 ky BP and 3.6 ± 0.03 ky BP. Hence, in the Holocene, the recurrence period of surface rupturing earthquakes is lower than thought before and other seismic sources, such as the Birkesdorfer Fault must be considered.
Mapping disturbance-dependent floodplain forests in the Naryn basin, Kyrgyzstan, using optical satellite imagery
Authors: Lauermann Magdalena , Betz Florian , Cyffka Bernd
Published: March 2022

In the semiarid climate of Central Asia the rivers and their associated floodplain ecosystems have a high relevance as regional hotspots of biodiversity and for the provision of ecosystem services. One of these rivers is the Naryn River in Kyrgyzstan. Upstream of the Toktogul Reservoir, which is the first barrier in the river course, the Naryn is still in a nearly natural state. The floodplain forests in its corridor depend directly on the disturbance regime of this river. Despite their ecological relevance they have not been investigated yet in detail. In particular the role of natural disturbance and anthropogenic effects for succession trajectories are not yet understood. This is a crucial issue for biodiversity conservation as ongoing plans for dam construction will lead to heavy modification of the natural disturbance regime. 
In this study, we contribute to fill this knowledge gap and use remote sensing to derive detailed ecological information for the entire central Naryn basin. We use multispectral satellite data of Sentinel-2 and digital elevation data from TanDEM-X to derive the floodplain forests in a supervised classification approach. The floodplain forests include among others pioneer vegetation, several classes of herbaceous vegetation and different forest types. 500 ground control points were collected in the field in 2019 and were complemented with additional points created based on high resolution rgb imagery. These points have been split into a training and validation data set to create a random forest classification model. As predictors, different multispectral indices like the NDVI and temporal metrics of them were used along with different terrain attributes like the distance to the river channel.
The results show that the random forest model with the combination of Sentinel-2 and TanDEM-X data can represent the complex structure of the floodplain forests along the Naryn river with high accuracies ranging from 62.4% for pioneer vegetation and 99.8% for open broad-leaved shrub. The forest structure shows a very heterogenous distribution along the longitudinal and lateral profile. The ecosystem response on the potential modification of the disturbance regime due to dam constructions is expected to be spatially heterogenous as well. Detailed forest habitat maps derived by remote sensing help to better understand natural processes and the potential effects of anthropogenic activities. Sentinel-2 data have high potentials for a efficient monitoring of forest habitats and their disturbance. Thus they are a very interesting data source for supporting forest conservation. Our forest habitat mapping for the Naryn floodplain provides a basis for further research, conservation planning and efficient monitoring.
Landscape-related ground ice variability on the Yukon coastal plain inferred from computed tomography and remote sensing
Authors: Pika Philip , Tanski George , Ulrich Mathias , Roy Louis-Philippe , Calmels Fabrice , Lantuit Hugues , Fortier Daniel , Fritz Michael , Vonk Jorien
Published: March 2022

Warming in the Arctic causes strong environmental changes with degradation of permafrost (permanently frozen ground). Active layer deepening (gradual thaw) and permafrost erosion (abrupt thaw) results in the mobilization and lateral transport of organic carbon, altering current carbon cycling in the Arctic. Ground ice content is a crucial factor limiting our understanding and ability to determine the rates and dynamics of permafrost thaw and its impact on potential thaw subsidence rates, changes in lateral hydrological pathways and its driving mechanisms on a landscape scale.

In this study we investigate ground ice content and its characteristics across the most dominant landscape units of the Yukon coastal plain (Canadian Arctic), using two spatially and technically contrasting approaches. In our bottom-up approach, twelve permafrost cores were collected from moraine, lacustrine, fluvial and glaciofluvial deposits using a SIPRE corer (mean drilling depth of 2 m) in spring of 2019. Ground ice and sediment contents within polygon centers were analyzed and classified using computed tomography and image recognition software (k-means). Our top-down approach quantified ice-wedge volumes from remote sensing imagery tracing the circumference of polygon troughs over the same area. Preliminary results - extrapolated to the entire coastal plain - show that the ground-ice content in polygon centers vary significantly from massive ice in the polygon troughs (wedge-ice). Total ice volume was estimated around 80.2 vol.-%, of which 68.2 ± 18.1 vol.-% was attributed to ground ice in polygon centers, and 12 ± 3.1 vol.-% of the landscape is massive ice in wedge-ice along polygon troughs. Additionally, differences among and between landscape units are also substantial, with highest ice volume contents in moraines landscapes, where polygon centers contain 58.8 vol.-% ground ice and wedge-ice volume is 16.2 vol.-%), while the lowest ice contents are found in glacio-fluvial deposits (22.1 vol.-% resp. 9.1 vol.-%).

Our results reveal a higher average and a larger variability in ground ice contents than previously found, suggesting a need of both ground-based measurements and remote sensing imagery to further our understanding of the future landscape subsidence, but also to avoid a likely under- or overestimation associated with the chosen approach. We conclude that due to the high ground ice contents on the Yukon coastal plain, substantial changes of the permafrost landscape will occur under current warming trends. These will include subsidence, abrupt erosion, changes in hydrology and organic carbon mobilization, degradation and export processes, which will differ between landscape units.
Utilization of microbial strains and communities as a precept of recycled organic fertilization
Authors: Kivelä Jukka , Hakalehto Elias
Published: March 2022

The by-products of food and forestry industry are usually considered as waste causing significant environmental problems. However, these by-products can be processed by using microbes to produce valuable chemicals as well as recycled fertilizers.

Microbial processes funded by the Finnish Ministry of Agriculture and Forestry have provided prime organic fertilizers from industrial side streams. In earlier greenhouse trial cellulosic deposits of the forest industries were upgraded with lactic acid and nitrogen-fixing bacteria providing 50% increased plant growth compared with the standard method. Another trial, the chicken manure treatment, consisted of microbiologically processed mix of manure, wood chips, and egg industry and slaughterhouse wastes. For example, this process yielded valeric acid and other valuable short-chain fatty acids (SCFA's). Simultaneously, both the methane yield and fertilizer nutritional value for the plants of the recycled residual fractions were remarkably upgraded by the microbiological treatments.

In Kasimir -project we are processing microbiologically by-products of industrial sauce production (Puljonki Oy, Nestle Professional). We get three different products out of this process: bone, fat, and protein fractions. Fat and protein fractions are processed further in biogas plant and bone fraction is processed as recycled fertilizer. In the case of microbiologically processed sauce industry wastes, the treatments with selected micro-organisms:

separated bone material from soft tissues

degraded and pulverized bones

eliminated and processed foam

Pulverized bones are used as component of recycled fertilizer, as they have quite a lot of plant nutrients. Total mineral contents of the organic bone meal were nitrogen (N) 3,9 %, phosphorus (P) 11 % and calcium (Ca) 22 %. Bone meal has been as a part of recycled fertilizer which has been used as fertilizer in field trials.

Besides the soil improvement, various food-grade chemicals, such as lactate and mannitol, were formed in some processes. All the microbial waste treatments produced high amounts of plant nutrients corresponding to standard mineral fertilizers but in a sustainable fashion.

Recycling food, paper and pulp industry by-products with microbiological biorefinery methods gives possibility to replace mineral oil-based materials. In addition, the microbiological nutrient recycling is more effective, and we can get more sustainable agriculture and food processing. With their accelerative effect in a bioprocess, the soil-derived microbial strains boost the agricultural circulation of substances and integrate the processing of industrial side streams into the soil ecosystem.
Magnetospheric Source of a Transpolar Auroral Arc: Coupled SWMF Simulation results
Authors: Hill Shannon , Pulkkinen Tuija , Al Shidi Qusai , Brenner Austin , Mukhopadhyay Agnit , Zou Shasha , Liehmon Michael
Published: March 2022

We present the first coupled MHD-ring current simulation results that produce the global transpolar auroral arc phenomenon. We examine a unique observation of a midnight transpolar auroral arc that is produced during compressed magnetosphere conditions and persistent into an extended interval of southward IMF and substorm onset. The IMAGE satellite FUV-WIC camera observed the transpolar auroral arc in the southern hemisphere on 15 May 2005. The IMAGE observations show that the transpolar auroral arc originates at 24 MLT and stretches sunward across the polar cap to form a theta aurora with dusk-dawn motion that does not correspond with IMF By sign reversal or continuous magnitude decrease. Even though the theta aurora is typically a northern IMF phenomenon, the IMAGE observations show that the theta aurora persisted for almost an hour under disturbed geomagnetic conditions with peak AL below -1500 nT and Dst around -100 nT. We use the University of Michigan Space Weather Modeling Framework (SWMF) global geospace simulation to study the ionospheric conditions and magnetotail configuration throughout the observation period. Our SWMF simulation results show good agreement with the observed SYM-H and AL indices during the event interval. In the simulation, we identify peaks in Joule heating, precipitation, and anti-sunward flows in the region where the theta aurora is observed. We also demonstrate the temporal evolution of the open-closed field line boundary with respect to the observed theta aurora location, which suggests that the theta aurora is a closed field line phenomenon. We analyze the open-closed field line boundary mapping into the magnetotail and search for causes of precipitation within the simulation as well as analyze the hemispheric conjugacy of the event.
Tsunami propagation and high-resolution inundation modelling of the 2017 Karrat rock avalanche and potential future tsunamis from proximal slope failures
Authors: Løvholt Finn , Glimsdal Sylfest , Harbitz Carl , Svennevig Kristian , Keiding Marie , Møller Jens Jørgen
Published: March 2022

On June 17, 2017, a 40 Mm3 rock avalanche generated a tsunami that impacted several coastal communities in Karrat Fjord, Central West Greenland. The tsunami run-up was 10-12 m high in the nearest village 30 kilometres away from the rock avalanche and caused four fatalities. The two villages most heavily affected are still evacuated. In the aftermath of this event, several unstable rock slopes have been discovered proximal to the 2017 rock avalanche. One of these volumes, coined Karrat 1, has a volume of about 0.5 km3 and is hence at least an order of magnitude larger than the volume involved in the 2017 event. To put this in perspective, it has a volume 2-3 times larger than the 2018 Anak Krakatau tsunami that led to more than 400 fatalities in Sunda Strait, Indonesia (which is also much more heavily populated). Hence, the Karrat 1 worst case scenario poses a threat to a much larger area than the event that took place in 2017 and could potentially affect the whole fjord system. In this study, we quantify the tsunami hazard from this unstable rock slope as well as the 2017 event. We first provide a set of landslide tsunami simulations using a frictional-collisional Voellmy type model coupled to a tsunamis model for the event in 2017 and compare it with observations. We found that the model results agree closely with observations of the tsunami run-up heights, observations of the tsunami arrival times, and the wave periods. The 2017 tsunami model was then used to calibrate the landslide source model for the future hazard, simulating the Karrat 1 landslide tsunami with an included uncertainty range. Extreme run-up heights (10-70 m) are found for the nearest villages, as well as complete inundation of entire low-lying villages, some more than 100 km away from the landslide release area. The large modelled run-up heights, involving extreme run-up heights and relatively short arrival times for the nearby villages, demonstrate the need for better understanding of the risk as well as risk-reducing measures. With few or no previous subaerial events that have taken place historically of this scale, the possible implications of a catastrophic release are widespread, but they also imply substantial uncertainties.
Present-day uplift of the East Kunlun Shan, Northern Tibetan Plateau
Authors: Liu Shaozhuo , Nocquet Jean-Mathieu , Xu Xiwei , Jónsson Sigurjón , Chen Guihua , Tan Xibin , Klinger Yann
Published: March 2022

Part of the 5-km high Tibetan plateau is undergoing eastward extension and crustal thinning, which might be the signature of a waning orogeny. However, the actual extent of such processes throughout the high plateau remains uncertain. Here, we examine the impact of tectonic, geodynamic, and climate-related surface processes on the vertical deformation monitored since 2007 by continuous Global Positioning System (GPS) across the East Kunlun Shan (EKS), the largest relief inside the Tibetan plateau. GPS measurements reveal 1-2 mm/yr uplift of the EKS relative to the 2-km-lower Qaidam Basin. However, the range-perpendicular shortening is limited at most to ~1 mm/yr, which is not adequate to drive the observed vertical motion. Instead, (1) the isostatic response to erosion and regional deglaciation since the last glacial period likely accounts for a significant fraction, up to 40%, of our GPS derived vertical rate, and (2) the EKS and its surrounding region to the south are probably still rising at ~1 mm/yr, rather than subsiding. Thus, our results show that this part of the northern Tibetan plateau is rising, demonstrating that the Tibetan Plateau is still actively growing, in contrast with previous models proposing the passive demise of the high plateau due to erosion and gravitational collapse.
The lithologic composition of Earth’s emerged lands reconstructed from the chemistry of terrigenous sediments
Authors: Greber Nicolas D.
Published: March 2022

The lithologic and chemical composition of the continental crust impacts Earth atmosphere and environment through e.g. weathering feedbacks and nutrient supply. However, despite being important for  the biological and atmospheric evolution of our planet, the question of how the lithological composition of Earth’s landmasses evolved from around 3.5 Ga to present is still a matter of considerable debate.

Here I will present a summary of the work that has been conducted by my colleagues and myself over the past five years and that improved our understanding of the chemical and lithological evolution of Earth landmasses since 3.5 Ga. Reconstructing the composition of past continents is difficult because erosion and crustal reworking may have modified the geologic record in deep time, so direct examination of the nature of igneous rocks could provide a biased perspective on the nature of the continents through time. A less biased record is likely provided by terrigenous sediments that average the composition of rocks exposed to weathering on emerged lands and we therefore use major and trace element concentrations and stable isotope compositions of shales as a proxy for the average composition of the emerged continents in the past. Applying a three-component mixing model to the sediment record shows that since 3.5 Ga, the landmasses that were subjected to erosion were dominated by felsic rocks. Furthermore, our reconstructed relative abundance of felsic, mafic and komatiitic rocks in the Archean is close to that currently observed in these ancient terrains. While our model does not suggest a strong change in the lithologic composition of Earth continents, we find a secular change in the average major and trace element concentration, with incompatible elements being more depleted and compatible elements being more enriched in the old landmasses.
Distance to cool spots, a practical design guideline for heat resilient urban areas
Authors: Kluck Jeroen , Kleerekoper Laura , Solcerova Anna , Erwin Stephanie , Klok Lisette , de Groot Monique , Koekoek Arjen
Published: March 2022

In the Netherlands municipalities are searching for guidelines for a heat resilient design of the urban space. One of the guidelines which has recently been picked up is that each house should be within a 300 meter of an attractive cool spot outside. The reason is that houses might get too hot during a heat wave and therefor it is important that inhabitants have an alternative place to go. The distance of 300 m has been adopted because of practical reasons. This guideline has been proposed after a research of the University of Amsterdam of applied sciences and TAUW together with 15 municipalities.

To help municipalities to take cool spots into account in their urban design the national organization for disseminating climate data has developed a distance to coolness map for all Dutch built up areas. This map shows the cool spots with a minimum of 200 m2 based on a map of the PET for a hot summer day (2*2 m2 spatial resolution). Furthermore the map shows the walking distance for each house (via streets and foot paths) to the nearest cool spot.

This map helps as a starting point. Because not all cool spots are attractive cool spots. A research in 2021 showed what further basis and optional characteristics those cool spots should have: e.g. sufficiently large, combination of sun and shadow, benches, quiet, safe and clean. In fact those places should be attractive places to stay for most days of the year.

With the distance to attractive cool spots municipalities can easily see which areas lack attractive cool spots. The distance to cool spot maps is therefore a way to simplify complex climate data into an understandable and practical guideline. This is an improvement as compared to using thresholds for temperatures and thresholds for duration of exceedance of those temperatures in a guideline.: Municipalities like this practical approach that combines climate adaptation with improving the livability of a city throughout the year.
Root activity for water uptake: a hydraulic approach 
Authors: Javaux Mathieu , Mehmandoostkotlar Ali
Published: March 2022

Despite most macroscopic models for root water uptake considering root length density (RLD) to describe root water uptake (RWU) distribution, there are numerous studies demonstrating inconsistencies between soil water content profile and RLD that can be attributed to the inability of some roots to extract water. In fact, the physical relationship between RWU and the root system ignores the hydraulic characteristics of the root. To cope with this rigid assumption, the activity of a root system can be defined as the portion of the root system extracting majority of soil water. Root water uptake activity depends on the hydraulic head gradient between root-soil interface and xylem and on root segment conductance, which are terms not considered in macroscopic models. Therefore, both soil and root hydraulic properties are critical in determining RWU activity. Yet, in real root systems, active root fraction is continuously changing due to root development, root adaptation and soil moisture heterogeneity, which are not possible to be assessed considering the currently available experimental facilities. Therefore, our aim in this study is threefold: (1) establish a theoretical framework to investigate root water uptake activity; (2) Investigate with 0D hydraulic architecture model and 3D architectural soil-root water flow model to estimate the active root fraction and to find the effective parameters on active root fraction and finally (3) demonstrate and provide orders of magnitude of active root fraction for real situations. The initial results showed that RWU activity for a single segment depends on radial hydraulic conductivity distribution if xylem conductance is not limiting. The active fraction of the root for fibrous and taproot systems at different ages with their realistic root hydraulic properties was investigated under equilibrium and realistic soil water potential and compared with some existing values in literature. The simulated active root fraction and obtained ones from the previous studies rarely exceed 30% of the whole root system. The active root fraction is therefore an important factor to know and characterize to properly estimate soil resistance and stress onset.
Partitioning meridional heat transport in Early Eocene Climatic Optimum model simulations
Authors: Kelemen Fanni Dora , Ahrens Bodo
Published: March 2022

The meridional heat transport is primarily governed by the geometry between the Earth and the Sun and it has been shown in previous studies that it is nearly invariant in different climates. Nevertheless, the processes, which contribute to the whole transport, do not stay invariable, but their changes compensate each other. Thus, the changes in the various transport processes give an insight into the climate system and its changes in different conditions, such as the high CO2 concentrations of the Early Eocene Climatic Optimum (EECO).

In our work we investigate the meridional heat transport and its elements in climate model simulations from DeepMIP focusing on the EECO. The meridional heat transport is divided into atmospheric and ocean heat transport. The atmospheric heat transport is further divided into moist and dry energy transport and also into transport by the meridional overturning circulation, transient eddies and stationary eddies. Annual and seasonal changes are compared in the preindustrial control simulation, in the 1xCO2 simulation and in simulations with high CO2 concentration values (3xCO2, 4xCO2, 6xCO2). We found that in a warmer climate, where the hydrological cycle is expected to be stronger, the transport of the meridional overturning circulation at the tropics, so the circulation of the Hadley cell, is more intense. Also, at the subtropics the energy transport of monsoon systems and at the mid-latitudes the energy transport of cyclones and anticyclones is different than in the control climate.

 
2021 North American Heat Wave Fueled by Climate-Change-Driven Nonlinear Interactions
Authors: Bartusek Samuel , Kornhuber Kai , Ting Mingfang
Published: March 2022

Extreme heat conditions in the Pacific Northwest US and Southwestern Canada in summer 2021 were of unprecedented severity. Constituting a 5-sigma anomaly, the heatwave affected millions, likely led to thousands of excess deaths, and promoted wildfires that decreased air quality throughout the continent. Even as global warming causes an increase in the severity and frequency of heatwaves both locally and globally, this event’s magnitude went beyond what many would have considered plausible under current climate conditions. It is thus important to attribute such an exceptional event to specific physical drivers and assess its relation to climate change, to improve projection and prediction of future extreme heat events. A particularly pressing question is whether any changing variability of atmospheric dynamics or land-atmosphere interaction is implicated in amplifying current and future heat extremes. Using ERA5 reanalysis, we find that slow- and fast-moving components of the atmospheric circulation interacted to trigger extreme geopotential height anomalies during this event. We additionally identify anomalously low soil moisture levels as a critical event driver: we find that land-atmosphere feedbacks drove nonlinear amplification of its temperature anomaly by 40% (contributing 3K of the 10K peak regional-mean anomaly), catalyzed by multidecadal temperature and soil moisture trends. This is supported by a model experiment demonstrating that soil moisture interaction may increase the likelihood of the observed monthly-scale regional temperature anomaly by O(10)x. We estimate that over the four recent decades of gradual warming, the event’s temperature anomaly has become 10–100 times more likely, transforming from a ~10,000-year to a 100–1,000-year occurrence. Its likelihood continues to increase, roughly exponentially, and it is projected to recur ~20-yearly by 2060 based on continued warming at a constant rate. Our results therefore suggest an important role of atmospheric dynamics and nonlinear land-atmosphere interactions in driving this exceptional heat extreme, promoted by a long-term warming trend due to anthropogenic climate change that will continue to increase the likelihood of such extremes under continued emissions.
Tidal effects in a global general circulation model: comparison between coarse and high resolution configurations
Authors: Borile Federica , Masina Simona , Iovino Doroteaciro , Pinardi Nadia , Cessi Paola
Published: March 2022

The energy budget of the global ocean circulation highlights the importance of winds and tides as main sources of energy. As wind forcing acts at the ocean surface, tidal potential affects the entire water column and, in regions of rough topography, it generates energy conversion from barotropic to baroclinic high frequency modes. An intercomparison is computed between experiments with and without tidal forcing, using a global ocean general circulation model in two different configurations, respectively mesoscale-permitting and mesoscale-resolving ones. Regardless of the resolution, the contribution of tides to the mean kinetic energy is negligible on the global scale, while it enhances the eddy kinetic energy, especially on continental shelves and rough bottom topography sites, where internal waves are generated before being dissipated or radiated away. The interaction between these waves and mesoscale features is enhanced in the higher-resolution experiments, and their effects on the mean circulation are analysed in two regions where the tidal activity is well documented: the North-West Atlantic Ocean and the Indonesian region. We investigate the impact of internal tides presence on the modelled tidal amplitude, and we include a topographic wave drag as an additional term of internal wave dissipation.
Arsenic dynamics in soils placed near old mining sites in SE Spain
Authors: Pérez-Sirvent Carmen , Martínez Sánchez Maria Jose , Martínez López Salvadora , Martínez Martínez Lucia Belén , Hernández Pérez Carmen , Gomez Martinez Carmen , Hernández-Córdoba Manuel , Bech Jaume
Published: March 2022

Arsenic is a Potentially Toxic Element (PTE), which is present in the soils/sediments of abandoned mining areas, such as the Sierra Minera de Cartagena La-Unión and the mining site of Mazarron (SE Spain) and its areas of influence. In order to assess the risk to human health and the ecosystem, it is necessary to know the nature of the materials that contain this PTE, their alterability and their speciation.

On the one hand, there is a geogenic relationship between this element and materials rich in phyllosilicates and Fe minerals. These minerals can constitute primary mineralisation such as sulphide veins (pyrite, arsenopyrite, etc.) or secondary mineralisation such as haematite, goethite, siderite, jarosite, etc., and can even be found as a mineral phase forming various arsenates. Another very important aspect is the climatology of the area, which coincides with a semi-arid Mediterranean climate with infrequent but very heavy rainfall.

The As concentration range in the studied areas is very wide (5000 -70 mg.Kg-1), with an average value of 150 mg.Kg-1, being As (V) the predominant species. Only soils located in wetland areas with permanent waterlogging can show significant concentrations of As(III). 

The As content in surface waters, such as runoff water, is low, only reaching significant values (>2 mg.L-1) when these waters are acid mine drainage and have pH values <2, coinciding in these cases with the presence of reduced As forms.

Particulate As is associated both with Fe oxides and hydroxides, through surface adsorption processes on Fe(OH)3 particles, and with carbonates, through precipitation reactions as calcium arsenate. These reactions are evident in some places such as wadis that transport particulate and dissolved materials from areas affected by mining, and mainly take place both in the riverbed and in flooding areas when rainfall events occur.

For an appropriate understanding of the main processes involved, a detailed scheme is given. It should be noted that the dynamics of this PTE is of a particular interest in the zones studied due to the proximity of urban sites.

 
Intensification of experimental climate and nitrogen addition on the sensitivity of shrubland communities globally
Authors: Liu Daijun , Zhang Chao , Ogaya Romà , Peñuelas Josep
Published: March 2022

Increasing climate change and nitrogen deposition are altering vegetation structure and functioning globally, yet the changes in species diversity, vegetation cover and functioning of global shrublands to these environmental changes are not systematically quantified. We conducted a global meta-analysis to quantify the shrubland responses relating to plant cover and density, species diversity and shrub encroachment as well as the functions for the shrub communities across 77 study sites to experimental warming, precipitation shifts and nitrogen addition. A sensitivity index was applied to account for the net vegetation responses of these vegetation metrics to the simulated drivers and explore the associations with the site background climate and soil nutrient variables. We observe that all the metrics were vulnerable to the treatments, the sensitivity was negative for most vegetation metrics under drought. Few vegetation metrics had sensitivity differences for the temporal scales (short-term vs long-term) of manipulations and successional stages (mature vs disturbed communities). Vegetation sensitivities to the environmental variables were associated with the site background climate and soil nutrient availability. Given the increasing challenges for future climate and nitrogen enrichment, quantifying the patterns of shrubland sensitivity and exploring their correlations with the site water and soil nutrient availability have important implications for management strategies and conservation of global shrublands.
Development of Next-Generation Air Quality Predictions for the United States
Authors: Stajner Ivanka ,   NOAA's FY19 Disaster Supplemental Wildfire 1 Project Team
Published: March 2022

NOAA is developing a next-generation air quality prediction system using a new limited-area, high-resolution online-coupled numerical weather and atmospheric composition model. This system integrates high-resolution meteorology provided by the Rapid Refresh Forecast System (RRFS) with atmospheric column chemistry from the EPA’s Community Multiscale Air Quality (CMAQ) modeling system within the Unified Forecast System (UFS) framework (https://ufscommunity.org/). RRFS-CMAQ uses anthropogenic emissions based on the U.S. EPA’s National Emissions Inventory and natural emissions estimated from process-based emission models such as FENGSHA and Biogenic Emission Inventory System.

 

In addition to the desire to unify modeling system codes for various applications and to introduce coupling of Earth system modeling components, such as those for weather and chemistry, a strong motivation for the development of RRFS-CMAQ is to provide a better representation of wildfire impacts on air quality. Wildfire emissions cause extremely high concentrations of air pollutants near fire locations. Depending on meteorological conditions, wildfire impacts can be carried downwind and affect air quality far away, even across the continent, like in recent summers when smoke from the U.S. west coast and Canadian fires impacted the eastern U.S. coast. Due to uncertainties in wildfire emission strength, evolution, composition and rise of smoke plumes, the impacts of wildfires on air quality are difficult to predict. Wildfire emissions in RRFS-CMAQ are specified by the NESDIS Blended Global Biomass Burning Emissions Product (GBBEPx). An evaluation system based on FIREX-AQ field data has been developed and used to evaluate current operational air quality predictions to establish a baseline that will be used to evaluate the prototype RRFS-CMAQ system as development continues. Planned refinements of RRFS-CMAQ include improvements in resolution, lateral boundary conditions, and the representation of wildfire emissions, such as smoke plume rise and diurnal variations of smoke emissions. Data assimilation is used to constrain distributions of atmospheric pollutants using observations of fine particulate matter (PM2.5) from AirNow, Aerosol Optical Depth (AOD) retrievals from the Visible Infrared Imaging Radiometer Suite (VIIRS) and NO2 retrievals from the TROPOspheric Monitoring Instrument (TROPOMI). To improve computational efficiency, machine learning emulators are also being developed for prediction of chemical transformations and tracer transport. To improve prediction accuracy, a bias correction post-processing procedure is planned to be introduced.
Lava flow dynamics during the 2021 Cumbre Vieja eruption, La Palma, Spain
Authors: Lev Einat , Birnbaum Janine , Hernandez Pedro , Barrancos José , Tramontano Samantha , Connor Laura , Connor Charles , Gabriel Jose
Published: March 2022

Over the three-month duration of the 2021 Cumbre Vieja eruption, lava flows covered an area of 1,241 ha. (12.41 km2) out of the total 8,790 ha (87.90 km2) impacted by the eruption overall. Consequently, lava is responsible for the destruction of a majority of the 3,000 buildings and large agricultural areas. At the beginning of the eruption, authorities used a model to forecast the inundation areas. We compare that preliminary forecast with those produced by other models, such as MOLASSES, Q-LAVHA, MrLavaLoba, VolcFlow, and others. The different forecasted flow fields are also compared with the evolution of the flow field as observed by satellite and aerial mapping. Where available, we anchor dynamic model predictions for observables such as flow velocity to local measurements obtained from velocimetry on UAV and ground-based videos of flowing lava. Lava properties used in the models are informed by petrological analysis of samples collected during the eruption. 
New insights on links between InSAR data products and ecohydrological parameters of raised peatlands.
Authors: Hrysiewicz Alexis , Holohan Eoghan P. , Dohonue Shane
Published: March 2022

Links proposed recently between tropical peatland Greenhouse Gas (GHG) emissions and peat-surface displacements as estimated remotely by Interferometry of Synthetic Aperture Radar (InSAR) could provide a basis for low-cost estimation of peatlands GHG emissions on a global scale. However, links between InSAR estimates and peat ecohydrological parameters remain uncertain. We compared InSAR products (interferograms, coherence maps and temporal evolutions of displacements) from Sentinel-1 data for two well-studied Irish raised bogs with in-situ ecohydrological measurements: Clara bog (Co. Offaly) and Ballynafagh bog (Co. Kildare). On the individual raised bog of Clara, we demonstrate heterogeneity of peat-surface displacements in both space and time: the western part of Clara is in subsidence (up to 15 mm.yr-1) while the eastern part shows uplift of some millimetres per year. In addition, these long-term evolutions are affected by annual oscillations of displacements due to the variations of water-table levels and to the meteorological conditions (rainfall and temperature). All of this, therefore, makes it difficult to use an InSAR-GHG proxy on temperate peatlands. Ballynafagh bog shows similar displacement behaviour to Clara bog. Furthermore, we show that the InSAR coherence is not affected by changes to vegetation wrought by a wildfire. This can be interpreted as evidence that the satellite-derived C-band radar waves penetrate through the 10-20 cm thick mossy vegetation layer and into the upper few 10’s cm of the underlying peat. Moreover, in-situ data show that the coherence is directly related to the soil moisture within the peat. Implications of this observation are (1) that InSAR displacements could be modified by soil moisture, resulting in biased InSAR-derived displacements during the annual oscillations and (2) that coherence mapping may provide a new method to estimate soil moisture on peatlands. Finally, future work should focus on directly validating InSAR displacements from in-situ data.
How does the spatial scale of natural climate fluctuations vary across timescales?
Authors: Kunz Torben , Laepple Thomas
Published: March 2022

What is the spatial scale of natural climate fluctuations, and how does it depend on timescale? To answer this question, we characterize the spatio-temporal correlation structure of global surface temperature fields by estimating frequency spectra of the effective spatial degrees of freedom (ESDOF), which can be interpreted as the effective number of independent spatial samples on the globe at each frequency. ESDOF spectra are estimated from the HadCRUT4 global gridded, monthly mean temperature anomaly dataset, based exclusively on instrumental measurements, covering the period 1850 to near-present. Because this dataset includes gaps (due to a lack of observations in certain months and regions on the globe), we employ a newly developed method that allows for bias-free spectral estimation from gappy data without interpolation across gaps. To correct for the anthropogenic warming trend, the data is detrended prior to the analysis, by subtracting the linear response to the anthropogenic global mean log(CO2-equivalent) forcing time series. The resulting ESDOF spectra reveal a reduction of the ESDOF value by a factor of 10, from about 130 (±15%) at sub-annual timescales to about 13 (±50%) at multi-decadal time scales. Uncertainties are estimated by applying the same analysis to a CMIP6 climate model ensemble, with HadCRUT4 data gaps imposed. To test for the possible impact of the data gaps, the ESDOF analysis is applied to global temperature fields with and without gaps, taken from both the climate model ensemble and from the NOAA 20th Century Reanalysis dataset. Results suggest slightly higher ESDOF values for complete fields, with the increase being negligible at sub-annual timescales and of the order of 15-20% at multi-decadal timescales. Overall, the results indicate that natural temperature variability at multi-decadal timescales is characterised by an ESDOF value between 10 and 20. Since it is unlikely, due to physical constraints, that the ESDOF value increases towards timescales longer than those resolved by the instrumental record, the above multi-decadal ESDOF estimate can be taken as an upper limit for centennial and longer timescales. This may have important implications in the context of paleo-climate reconstructions and their comparison with model simulations.
Impact of structural heterogeneity on solute transport and mixing in unsaturated porous media: An experimental study
Authors: Borgman Oshri , Gomez Francesco , Le Borgne Tanguy , Méheust Yves
Published: March 2022

Solute transport in unsaturated porous media plays a crucial role in environmental processes affecting soils, the unsaturated zone, and aquifers lying below. These processes include nutrient and pesticide leaching in soils, contaminant migration to aquifers and degradation in the vadose zone, and nutrient exchange at the soil-river interface, to name a few. Natural porous media are characterized by structural heterogeneity in the pore sizes disorder and their spatial arrangements. The impact of pore size heterogeneity on the spreading and mixing of a solute plume, and the resulting reaction rates, are not well understood for unsaturated flow. In addition, these processes can be affected by incomplete mixing at the pore scale. Thus, direct pore-scale experimental measurements are needed to gain a comprehensive understanding of the mixing state of the system. Our goals are to 1) study the impact of structural heterogeneity on fluid phase distributions and 2) establish how the arrangement of fluid phases impacts solute spreading and mixing. We use micromodel experiments with two-dimensional porous media. The samples are created by placing an array of circular posts in a Hele-Shaw-type flow cell. We vary the heterogeneity by controlling the circular posts’ diameters disorder and correlation length of their spatial distribution. In the first stage of each experiment, we simultaneously inject liquid and air to establish an unsaturated flow pattern with a connected liquid phase cluster. Then, we introduce a conservative fluorescent solute pulse with the moving liquid phase. We track the solute concentration and gradients’ evolution by taking periodic images of the flow cell and analyzing their fluorescence intensity. In addition to unsaturated flow experiments, our system allows us to study the impact of pore size disorder and correlation on solute mixing in saturated porous media and even directly quantifying fast reaction products’ concentrations. Initial results confirm previous findings on the impact of desaturation on enhanced mixing rates for a single porous medium geometry. In addition, our use of a continuous solute pulse highlights regions that maintain a high mixing rate at the interface between mobile and stagnant liquid phase parts. Ongoing experiments explore the impact of increasing pore size disorder and correlation length on fluid phase distributions and mixing rates.