bluuebunny/crossref_metadata_2025 huggingface dataset:
Artificial intelligence for the monitoring of Antarctic supraglacial lake dynamics in 2015-2021 using Sentinel-1 SAR and optical Sentinel-2 data
Authors: Dirscherl Mariel , Dietz Andreas , Kuenzer Claudia
Published: March 2022

Earth Observation (EO) provides a wealth of data for the monitoring of the Antarctic continent. In this context, data of the Sentinel-1 Synthetic Aperture Radar (SAR) and optical Sentinel-2 satellite missions of the European Copernicus programme deliver valuable information on key ice sheet parameters including the location of the calving front and grounding line, the ice velocity and elevation as well as the Antarctic surface hydrological network. The monitoring of the latter is crucial for an improved understanding of processes such as hydrofracture triggering ice shelf collapse and ultimately ice flow accelerations and increased ice discharge. To establish a monitoring service for supraglacial lake extent delineation in Sentinel-1 SAR and optical Sentinel-2 imagery, a fully automated processing chain based on machine learning and deep learning was developed and integrated within the internal processing infrastructure of the German Aerospace Center (DLR).

Here, we present first results of the implemented machine learning processing pipeline over six major Antarctic ice shelves. In particular, the full archive of Sentinel-1 and Sentinel-2 was exploited to provide bi-weekly supraglacial lake extent mappings during 2015-2021 at unprecedented 10 m spatial resolution. The results over Antarctic Peninsula ice shelves reveal comparatively low lake coverage in 2015-2018 and high lake coverage during summers 2019-2020 and 2020-2021. Over East Antarctic ice shelves, supraglacial lake extents fluctuated more substantially with comparatively high lake coverage during most of 2016-2019 and low lake coverage throughout melting season 2020-2021. Further, the data reveal a coupling between supraglacial lake formation and the near-surface climate, the local glaciological setting and large-scale atmospheric modes.

The final data products on Antarctic supraglacial lake extent dynamics during 2015-2021 are available via the GeoService of the Earth Observation Center (EOC) at DLR. To establish a near-real-time monitoring service on supraglacial lake dynamics in the future, the full processing pipeline is currently refined and data products will be made readily available for download via the EOC GeoService. In this context, we are building upon the expertise of the Polar Monitor project and IceLines, a processor for automated calving front extraction over the Antarctic coastline.
Ageing Society in Developed Countries Challenges Carbon Mitigation 
Authors: Zheng Heran , Long Yin , Wood Richard , Moran Daniel , Zhang Zhengkai , Meng Jing , Feng Kuishuang , Hertwich Edgar , Guan Dabo
Published: March 2022

Western countries are ageing, meaning a larger proportion of their citizens will be of senior age (60+) in the years ahead. However, the impacts of the lifestyles of these senior-aged people on global carbon mitigation are poorly understood. Here, we quantify the evolution of greenhouse gas (GHG) footprints driven by household consumption across age groups. We found that the senior-aged group has played a leading role in driving up GHG emissions in the past decade. The senior age group in most of the 32 developed countries studied was on the way to becoming the largest contributor to those countries’ GHG emissions, with their shares of the national total consumption-based emissions increasing from 25.2% to 32.7% between 2005 and 2015. The seniors in the US and Australia have the highest per capita footprints, twice the Western average. The trend was mainly due to the changes in expenditure patterns of seniors, such as high expenditure on carbon-intensive products (e.g. heating and cooling larger home area per capita). The high level of spending of seniors was strongly supported by their accumulated wealth. However, their wealth elasticity of expenditure is lower than other age groups, suggesting the consumption pattern may have a relatively small change while their wealth is gradually shrinking. The increasing carbon footprints of senior citizens is likely to drive the domestic production due to their higher share of expenditure for shelter energy and food products, thus having limited effects on international carbon leakage. The demographic change poses more challenges in local mitigation and calls for deeper public mitigation efforts, especially for the US.
Creep on seismogenic faults: Insights from analogue earthquake experiments
Authors: Rosenau Matthias , Corbi Fabio , Cubas Nadaya , Funiciello Francesca , Kosari Ehsan , Maillot Bertrand , Mastella Giacomo , Oncken Onno , Rudolf Michael , Souloumiac Pauline , Visage Sarah
Published: March 2022

Tectonic faults display a range of slip behaviours including continuous and episodic slip covering rates of more than 10 orders of magnitude. To gain insight into the slip behaviour of brittle faults, we performed laboratory stick-slip experiments at low pressure using dry “sticky” rice as rock analogue material. Rice has been shown to be a valuable material obeying the rate and state friction laws qualitatively and quantitatively and mimicking the full spectrum of seismogenic fault behaviour (“ricemic cycles”) depending on boundary conditions. The deformation mechanism is granular flow and as such transient hardening and weakening phenomena such as strain localization or stick-slip are accompanied by dilation and compaction, respectively. Such a rheology might be similar in rocks at various scales (grain scale to regional tectonic scale).

We here report on ring shear test experiments on a range of rice varieties, including full-grain and crushed sorts. We imposed boundary conditions (i.e., normal load, shear velocity) scaled down from nature under which our fault analogue shows a variety of slip behaviours ranging from slow and quasi-continuous creep to episodic slow slip to dynamic rupture. The experiments demonstrate that significant interseismic creep (up to far-field loading rate) and earthquakes may not be mutually exclusive phenomena for a given location along a fault. Moreover, creep signals vary systematically with the fault’s seismic potential. Accordingly, the transience of interseismic creep scales with fault strength and seismic coupling as well as with the maturity of the seismic cycle. Loading rate independence of creep signals suggests that the long-term stationary mechanical properties of faults (e.g. seismic coupling) can be inferred from short-term observations (e.g. aftershock sequences). Moreover, we observe the number and size of small episodic slip events to systematically increase towards the end of the seismic cycle providing an observable proxy of the relative shear stress state on seismogenic faults. 

Importantly, very weak faults (with low effective normal loads) in a late stage of their seismic cycle might creep at rates very close to far-field loading for extended periods of the interseismic stage (~decades before failure). Given that we typically observe only a fraction of seismic cycles with high resolution (with geodetic methods) in nature, this might lead to the false belief of the fault being aseismic and not hosting large earthquakes. We thus demonstrate that seismic and aseismic behaviour might not necessarily be mutually exclusive.
Spatial multi-modality as a way to improve both performance and interpretability of deep learning models to reconstruct phytoplankton time-series in the global ocean
Authors: Roussillon Joana , Littaye Jean , Fablet Ronan , Drumetz Lucas , Gorgues Thomas , Martinez Elodie
Published: March 2022

Phytoplankton plays a key role in the carbon cycle and fuels marine food webs. Its seasonal and interannual variations are relatively well-known at global scale thanks to satellite ocean color observations that have been continuously acquired since 1997. However, the satellite-derived chlorophyll-a concentrations (Chl-a, a proxy of phytoplankton biomass) time series are still too short to investigate phytoplankton biomass low-frequency variability. Machine learning models such as support vector regression (SVR) or multi-layer perceptron (MLP) have recently proven to be an alternative approach to mechanistic ones to reconstruct Chl-a past signals (including periods before the satellite era) from physical predictors, but they remain unsatisfactory. In particular, the relationships between phytoplankton and its physical surrounding environment are not homogeneous in space, and training such models over the entire globe does not allow them to capture these regional specificities. Moreover, if the global ocean is commonly partitioned into biogeochemical provinces into which phytoplankton growth is supposed to be governed by similar processes, their time-evolving nature makes it difficult to impose a priori spatial constraints to restrict the learning phase on specific areas. Here, we propose to overcome this limitation by introducing spatial multi-modalities into a convolutional neural network (CNN). The latter can learn with no particular supervision several spatially weighted modes of variability. Each of them is associated with a CNN submodel trained in parallel, standing for a mode-specific response of phytoplankton biomass to the physical forcing. Beyond improving performance reconstruction, we will show that the learned spatial modes appear physically consistent and may help to get new insights into physical-biogeochemical processes controlling phytoplankton repartition at global scale.
Effects of soil warming on in situ fine root exudation rates in a temperate forest soil
Authors: Heinzle Jakob , Liu Xiaofei , Tian Ye , Kwatcho-Kengdo Steve , Borken Werner , Inselsbacher Erich , Wanek Wolfgang , Schindlbacher Andreas
Published: March 2022

Trees invest up to one third of the carbon (C) fixed by photosynthesis into belowground allocation, including fine root exudation into the rhizosphere. Rising soil temperatures in a warmer world could modify the allocation of labile C below ground, thereby affecting biogeochemical cycling in forest soils. Up to date our understanding of how fine root exudation of labile carbon compounds responds to warming is yet emerging and in-situ analyses under warming conditions are scarce, especially in mature forests. Using a C-free cuvette incubation method, we investigated in situ rates of root exudation from fine roots in a mature spruce forest across three seasons after 14 and 15 years of warming in the Achenkirch soil warming (+4°C) experiment. In addition, we run a complementary short-term experiment on root exudation, during which we increased soil temperatures on warmed plots stepwise up to a difference of 12°C between treatments within a few days. We found no effect of long-term soil warming on in situ root exudation rates (n = 120 roots sampled). Mean exudation rates per biomass were 16.23 ± 4.03 and 17.94 ± 2.94 µg g-1 h-1 on control and warmed plots respectively, with highest rates found in the late growing season in both treatments. Exudation rates were positively related to the specific root length and were negatively related to soil moisture, but unrelated to soil inorganic N availability and in situ soil temperature. However, the short-term temperature manipulation resulted in an exponential increase of estimated root exudation rates with soil temperature. Our results therefore indicate that fine root exudation from mature trees in the studied ecosystem is inherently controlled by soil temperature, but an interplay with other parameters such as nutrient availability, root morphology and/or soil moisture are the dominant controlling mechanisms across the seasons in the long run. Our observations further indicate that the long-term soil warming by 4°C caused only a subtle increase in root exudation per fine root surface area or per fine root biomass.
Electronic waste as a source of rare earth element pollution: Leaching, transport in porous media, and the effects of nanoparticles
Authors: Brewer Aaron , Dror Ishai , Berkowitz Brian
Published: March 2022

Rare earth elements (REEs) are an emerging pollutant whose increasing use in various technological applications causes increasing risk of environmental contamination. Electronic waste (E-waste) could be one major source of REE pollution, as E-waste typically contains elevated REE concentrations and is often handled in unsafe and environmentally hazardous ways. Here, a series of leaching assays revealed that <1% of REEs available in a representative E-waste were released except at acidic conditions (pH 2) rarely observed in nature. If REEs are leached from E-waste, the extent of their spread in the environment will depend, in large part, on their mobility through porous media. Measurements of REE transport through saturated sand demonstrated extremely limited mobility except at acidic conditions (pH 2), though significant REE retention by the substrate still occurs at this low pH. Similar experiments in a natural soil found REE mobility to be even lower in that substrate, with complete REE retention even after the passage of up to 215 pore volumes of a 500 ppb REE solution. Aqueous REEs are therefore not expected to be highly mobile in the environment. The presence of natural or anthropogenic nanoparticles may affect REE behavior during leaching and/or transport. Measurements indicated that silica nanoparticles can increase the concentration of fluid-mobile REEs during E-waste leaching, but both plastic and silica nanoparticles have a negligible effect on REE transport. Ultimately, the experiments and analysis presented here suggest that the threat of REE pollution from E-waste is minimal except at specific sites with unusual environmental conditions.
Topsoil organic carbon in China is mainly affected by internal nitrogen and external temperature
Authors: Zhang Yi
Published: March 2022

As a major carbon emitter, China’s decarbonisation will contribute to global climate action. The verification of topsoil C distribution in China and its influence factors was an urgent problem for the carbon neutrality of China. . To address this issue, topsoil (0-20 cm) and climate data for 7,857 sites were selected. The soil organic carbon (SOC) distribution in forestland, grassland, and farmland in seven districts of China was analyzed. The correlations and contribution rates of external (elevation-E, temperature-T, and rainfall-R) and internal factors (fractal dimension-D, soil total nitrogen-STN, soil total phosphorus-STP, pH, and C/N ratio) were explored. We found that SOC in China gradually increased from the west to east, with a mean value of 11.20 g kg-1. The SOC content in northeast China was higher than elsewhere in the country. The SOC of different land use types followed the order of forestland > farmland > grassland (P <0.05). All of the factors influencing SOC, with the exception of R, had distinct differences in their spatial patterns and land use types. The most important internal factor was STN, followed by STP, while the most important external factor was T, followed by R. The factor that made the greatest contribution to the SOC was STN. There was a relationship between the SOC distribution and the Hu Huanyong Line, the 6.5-10.5℃ T contour line in the south of China. These results provide theoretical support for soil C cycle and prediction research, which will enable the issues surrounding climate change in China to be confronted.

Key words: soil organic carbon, distribution pattern, internal factors, external factors, China
Hydrology at its extreme: climate change, societal impacts and natural hazards in the land of fire and ice
Authors: Finger David C.
Published: March 2022

There is a reason why Iceland is frequently called the land of fire and ice. Located on the mid-Atlantic ridge in the North Atlantic Ocean, Iceland is frequently exposed to explosive volcanic eruptions. Furthermore, due to its geographic location cold Arctic winds from the North and the warm humid winds coming from the Gulf of Mexico collide. The particular geographic location is the reason why over 10% of the Island area is covered by glaciers, precipitation can exceed 10´000 mm a-1, and glacial flood can reach several 100’000 m3 s-1. Regardless of the arctic winds, the extreme precipitation, and the frequent eruption, the original Icelandic vegetation has developed a resilience to with sand almost any natural hazard. However, with the arrival of the first settler over a millennium ago Iceland has been subject to dramatic deforestation due to intense sheep and horse farming. These anthropogenic impacts have severely mitigated the resilience of the Icelandic vegetation, altering the erosion patterns and finally also impacting the natural water flow. The Rangárvellir area in southern Iceland is an ideal location to study the interaction of human impacts, natural hazards, and consequences for the natural water cycle. Deforestation and intensive farming have decreased the resilience of the local ecosystems, leading to severe land degradation and extensive soil erosion. Since the beginning of the 20th century, diverse restoration measures have been implemented across Rangárvellir. Long-term monitoring programs demonstrate how restoration can help mitigate hydrometeorological and volcanic risks, providing a representative example of nature-based solutions. For this purpose, we present a metadatabase (http://rangarvellir.ru.is/) providing an overview of previous and ongoing research on land restoration, land management, reforestation, hydro-meteorological monitoring, and vegetation mapping. All relevant past and ongoing research and restoration projects are described in order to demonstrate the importance of an all-inclusive landscape restoration approach. The study concludes by outlining the importance of nature-based solutions and highlights the interaction between research projects in the frame of restoration and land reclamation efforts.
Magnetocrystalline anisotropy of out-of-phase magnetic susceptibility in hematite 
Authors: Hrouda Frantisek , Ježek Josef , Chadima Martin
Published: March 2022

 Out-of-phase component of AC magnetic susceptibility (opMS) in four single crystals of hematite from Minas Gerais, Brazil was investigated. The phase angle ranges from 1° to 6° along the c-axis and slightly exceeds 25° along the basal plane (in the standard field 400 A/m at the operating frequency 1220 Hz). The opMS in the basal plane shows strong field dependence and virtually no frequency dependence. Along the c-axis, opMS is at least three orders lower and increases with field only slowly; it is similar at the frequencies 976 Hz and 3,904 Hz, while it is clearly higher at 15,616 Hz. The opMS vs. T curve measured along basal plane drops acutely between 680 °C and 710 °C, evidently indicating the Curie (Néel) temperature of hematite. The same curve along c-axis passes more or less parallel to the abscissa in the entire temperature interval investigated.

Directional opMS was measured in 320 independent directions from which the opAMS tensor was calculated using standard linear technique. The minimum opAMS directions are parallel to the c-axis, while the maximum and intermediate opAMS directions lie within basal plane. The differences between measured values and those calculated from the opAMS tensor are relatively small in the vicinity of the maximum opAMS direction and very high in the vicinity of the minimum opAMS direction. All this indicates that the second rank tensor is not the best representative of the spatial variation of the directional opMS of hematite single crystals. In multi-crystal assemblages, however, summation of many oriented grains filters out the non-tensorial parts of the grain opAMS and the resultant opAMS is well represented by a tensor. This result is similar to that of in-phase magnetic susceptibility in hematite investigated in Hrouda et al. (2020).
Long-term climatological SM2RAIN dataset for drought monitoring
Authors: Mosaffa Hamidreza , Filippucci Paolo , Massari Christian , Ciabatta Luca , Brocca Luca
Published: March 2022

Drought is a natural disaster that has serious economic, social and environmental impacts. Drought monitoring is one of the components of drought risk management. The main requirement of drought monitoring is to have a reliable and accurate long-term rainfall dataset. SM2RAIN datasets are among the available rainfall products that estimate rainfall from satellite soil moisture observations. The high performance of SM2RAIN products has been shown in several studies over different regions of the globe. The aims here are as follow: 1) to develop the long-term climatological SM2RAIN datasets that cover the period of 1998-2020 at 0.25° spatial and monthly temporal resolution on the global scale. This dataset is designed by merging two rainfall SM2RAIN products including SM2RAIN-CCI (1998-2015) and SM2RAIN-ASCAT (2007-2020). For this purpose, the quantile mapping method is applied to remove the bias between these two products and match the monthly values. In the QM method, a correction factor is calculated during the overlap period (2007-2015) as a reference period and then applied to for the entire study period, 2) to analyses of drought based on standardized precipitation index on the global scale. In addition, the analysis is compared with drought analysis of other ground observations and reanalysis rainfall products such as the Global Precipitation Climatology Project (GPCP) and ERA5. The results show that the developed SM2RAIN-based rainfall product has the potential to improve global drought monitoring by capturing the drought events accurately.
Observation-based bankfull discharge estimates to improve global flood models
Authors: Wortmann Michel , Slater Louise , Boothroyd Richard , Sambrook Smith Greg , Neal Jeffrey
Published: March 2022

The conveyance capacity of rivers is a key uncertainty in regional and global flood models. Most models resort to assumptions of uniform discharge recurrence of 1-2 years, using modelled discharge. While this assumption may hold on average, reach-scale bankfull discharge has been shown to vary significantly at the global scale. To improve this key boundary condition in large-scale hydrodynamic models, we have coupled emerging understanding of the hydrological and geomorphological drivers of bankfull discharge with recent advances in remote sensing products and machine learning. Using measured bankfull discharge values derived from stage-discharge and width-discharge relationships as reference, we construct a data-driven model to estimate bankfull discharge globally at the reach scale (30m centreline pixels and sub-kilometre vector reaches). Various remote sensing products are used as predictor variables that pertain to either catchment-wide or reach-specific attributes. This includes river geometry and floodplain metrics derived from Landsat water masks that have also been used to construct the underlying river network. This novel river network was designed to be as DEM-independent as possible, allowing for multi-thread channels, bifurcations and canals. Early results indicate good agreement between predicted and independent reference values.

The new dataset will be used to improve the parametrisation of a state-of-the-art global flood model as part of the EvoFlood research project (NERC, UK), but is also expected to be useful for other hydrological and hydrodynamic models as well as investigations at regional to global scales.
Soil creep and leakage process in shallow fissures on a karst slope based on particle composition analysis
Authors: Cen Longpei , Peng Xudong , Dai Quanhou
Published: March 2022

Rocky desertification has become one of the global ecological environmental problems. Karst rocky desertification area of southwest China is suffering from ecosystem degradation, and the combination of water and soil resources determines the stability of their ecosystems. In recent years, soil leakage has attracted attention because it was that under the development of carbonate shallow fissures, the water and soil along the such pipes as shallow fissures leaks underground, resulting in the allocation of soil and water underground, affecting the integrity of the overlying ecosystem. This study aimed to reveal the leakage loss process, characteristic and mechanism of soil in fissures on sloping lands in the karst area, taking fissures on sloping lands in karst plateau of Guizhou province as the research object, combined with the methods of paint marking and soil particle analysis was conducted to study the leakage loss process of soils in fissures. The result showed that rainstorm or downpour is the key factor of soil fissure leakage loss, and its leakage form is mainly soil creep. Soil creep displacements of different fissure at 104.5 mm rainfall event between 1.0 cm and 2.5 cm, accounting for more than 62.5% of the displacement at 332.7 mm rainfall event, while the soil creep displacement of fissures just range from 0.2 cm to 0.3 cm at the larger rainfall of 181.5; the particle content with different particle sizes in rock-soil interfaces and soils of six fissures selected under 3 precipitation events (104.5, 151.2 and 332.7 mm) showed that the fissure soil does not leak down uniformly, but some particles at the soil layers or rock-soil interfaces leak to the lower layer at random in the process of creep leakage loss. In other words, the occurrence of soil layers and particles are accidental, and the soil particles in the rock-soil interfaces and the soil layers of fissures have the possibility to leak down. Facts proved that the soil creep leakage loss in fissures is a complex process which is determined by the internal factors such as fissure structure, fillings characteristics and bottom connectivity, and such external factors as rainfall etc.
Key words: underground leakage loss; soil; karst fissure; sloping land; karst plateau
Assessing the effects of climate and land use changes on the distribution and growth of important plants species for pollinators
Authors: Lanssens Benjamin , François Louis , Hambuckers Alain , Moen Merijn , Anders Tim , Tölle Merja , Verma Arpita , Remy Laura
Published: March 2022

Pollination is a key ecosystem service vital to the preservation of wild plant communities and good agricultural behaviour. However, pollinators are rapidly declining in Europe, primarily as a result of human activity and climate change. Therefore, there is growing concern that observed declines in insect pollinators may impact on production and revenues from pollinator-dependent crops. In the forest, the presence of pollinators depends strongly on the openness of the canopy and the presence of wild plants that attract pollinators. The distribution of such plants is, therefore, crucial for estimating the pollinators presence. In general, however, there is incomplete knowledge of where those wild plants occur and how well they grow. To overcome this issue, we developed a species distribution model to predict the potential presence of important plant species for pollinators under present and future climatic conditions. The result of the distribution model is then refined using the dynamic vegetation model CARAIB. By combining the results of the distribution model and CARAIB, we can determine where the plants are located and calculate their net primary productivities.
Characterizing spatio-temporal changes in volcanic rock aquifer compaction using satellite-based geodetic measurements (GNSS and InSAR) 
Authors: Jones Mireia , Gonzalez Pablo J. , Charco Maria , Marrero Rayco , Eff-Darwich Antonio
Published: March 2022

Volcanic reservoirs are usually the main source of freshwater on volcanic islands. On Tenerife Island, groundwater extraction occurs by drilling horizontal water tunnels. This has resulted in a sustained extraction due to the hundreds of water tunnels that have been drilled since around 1900 for agriculture, industry and freshwater supply. The extraction is exceeding the natural recharge, leading to groundwater table decline, locally up to 200+ m of down drop. Since 2000, satellite radar interferometry (InSAR) applied to measure surface deformation has located several subsidence bowls (e.g., Fernandez et al., GRL 2009). The localized surface deformation patterns have been correlated with water table changes and hence aquifer compaction. By overlapping InSAR data time series with Global Navigation Satellite Systems (GNSS) we hope to better understand the compaction processes around volcanic aquifers and explain the observed surface deformation.  This knowledge could help make decisions about water management policies.

To investigate the compaction processes affecting the volcanic rock aquifers of Tenerife, we utilize simultaneous geodetic observations using Global Navigation Satellite Systems time series (GNSS) and satellite radar interferometry over the period October 2014 to December 2021. The GNSS network is composed of 10 GNSS sites and it was processed by the Nevada Geodetic Laboratory (Blewitt et al., 2018; http://geodesy.unr.edu/NGLStationPages/gpsnetmap/GPSNetMap.html). The satellite radar interferometry time series were computed using Sentinel-1 ascending and descending orbits with ID tracks 060 and 096, respectively. Finally, we analyzed the spatio-temporal behaviour using statistical methods to identify distinct regions more or less affected by the underlying aquifer mechanical processes. 

Blewitt, G., W. C. Hammond, and C. Kreemer (2018), Harnessing the GPS data explosion for interdisciplinary science, Eos, 99,https://doi.org/10.1029/2018EO104623.

Fernandez, J., et al. (2009), Gravity-driven deformation of Tenerife measured by InSAR time series analysis, Geophys. Res. Lett., 36, L04306, doi:10.1029/2008GL036920.
Geophysical research and monitorind within a block-layered model with inclusions of hierrchical structure
Authors: Hachay Olga , Khachay Andrey
Published: March 2022

A review of works is presented in which new models of continuum mechanics generalizing the classical theories of elasticity are being intensively developed. These models are used to describe composite and statistically inhomogeneous media, new structural materials, as well as complexly constructed massifs in mine and ground conditions; and in the study of phenomena occurring in permafrost under the influence of heating processes. A characteristic feature of the theory of media with a hierarchical structure is the presence of explicit or implicit scale parameters, i.e. explicit or implicit non-locality of the theory. This work focuses on the study of the non-locality effects and internal degrees of freedom reflected in internal stresses that are not described by the classical theory of elasticity, but can be potential precursors of the development of a catastrophic process in a rock mass.
The existential space of climate change and systemic risks
Authors: Huggel Christian , Bouwer Laurens M. , Juhola Sirkku , Mechler Reinhard , Muccione Veruska , Orlove Ben , Wallimman-Helmer Ivo
Published: March 2022

Climate change is widely recognized as a major risk to societies and natural ecosystems but the cascading processes of impacts through complex and interconnected systems are poorly understood. In fact, the high end of the risk, i.e. where risks become existential, is poorly framed, defined and analyzed by science. This gap is at odds with the fundamental relevance of existential and systemic risks for humanity, and it also limits the ability of scientific communities to engage with the emerging debates and narratives about the existential dimension of climate change that have recently gained considerable traction.

In this contribution we address this gap by scoping and defining existential risks related to climate change. We first review the context of existential risks and climate change, as related to systemic risks and drawing on research in fields such as global catastrophic risks and the so-called “Reasons for Concern” in the reports of the Intergovernmental Panel on Climate Change. We also consider how existential risks are framed in the civil society climate movement and what we can learn in this respect from the COVID-19 crisis, which is also a primary learning space for better understanding for both, systemic and existential risks. We then develop a definition that distinguishes between a narrower scope of conditions that threaten survival and basic needs, and a broader scope of conditions that threaten a certain level of well-being, consisting of meeting acceptable living standards. Based on this, we define six dimensions of existential risks of climate change, including the mechanisms they unfold, the systems affected, the dimension and magnitude, the probability of occurrence, time horizon and speed, and the scale of the threat. Our contribution is intended to support further scientific analysis of existential and systemic risks as part of the full risk space associated with climate change. Considering the widespread lag in awareness and regulation related to systemic risks, the results of this study should make the risk space better defined, more tangible and hence more conducive to preventive action by policy.
EMHD Grad–Shafranov reconstruction of the electron diffusion region within a flux rope
Authors: Korovinskiy Daniil , Panov Evgeny , Nakamura Rumi , Hosner Martin
Published: March 2022

The compressible electron magnetohydrodynamics (EMHD) Grad–Shafranov (GS) reconstruction technique is applied to recover a magnetic reconnection electron diffusion region (EDR) immersed in a flux‐rope type dipolarization front observed by the Magnetospheric Multiscale (MMS) mission on 8 September 2018 at nearly 14:51:30 UT. An event was reported in the study of Marshall et al. (JGR, 2020). EMHD GS reconstruction confirms mainly the results of the cited study. Particularly, MMS1 is found to cross the very center of EDR at the initial steady-state stage. The reconstruction results allow also the suggestion that the reported X-line and EDR were not single ones, but rather the chain of X-lines (two at least) separated in north-south direction for about 10 de could exist.
PM2.5 influence on Urban Heat Island (UHI) effect in Beijing and the possible mechanisms
Authors: Yang Guowei
Published: March 2022

Whether the urban heat island (UHI) is affected by air pollution in urban areas has attracted much attention. By analyzing the observation data of automatic weather stations and environmental monitoring stations in Beijing from 2016 to 2018, we found a seasonally dependent interlink of the UHI intensity (UHII) and PM2.5 concentration in urban areas. PM2.5 pollution weakens the UHII in summer and winter night, but strengthens it during winter daytime. The correlation between the UHI and PM2.5 concentration has been regulated by the interaction of aerosol with radiation, evaporation and planetary boundary layer (PBL) height. The former two change the surface energy balance via sensible and latent heat fluxes, while the latter affects atmospheric stability and energy exchange. In summer daytime, aerosol-radiation interaction plays an important role, and the energy balance in urban areas is more sensitive to PM2.5 concentration than in rural areas, thereby weakening UHII. In winter daytime, aerosol-PBL interaction is dominant, because aerosols lower the PBL height and stabilize atmosphere, weaken the heat exchange with the surrounding, with more heat accumulated in the urban areas and the increased UHII. Changes in evaporation and radiation strengthen the relationship. At night, the change of UHII more depends on the energy stored in the urban canopy. Aerosols effectively reduce the incident energy during daytime, and the long-wave radiation from the buildings of urban canopy at night becomes less, leading to a weakened UHII. Our analysis results can improve the understanding of climate-aerosols interaction in megacities like Beijing.

How to cite. Yang, G., Ren, G., Zhang, P., Xue, X., Tysa, S. K., Jia, W., Qin, Y., Zheng, X., and Zhang, S.: PM2.5 Influence on Urban Heat Island (UHI) Effect in Beijing and the Possible Mechanisms, Geophys Res Atmos, 126, https://doi.org/10.1029/2021JD035227, 2021.
Super-Resolution based Deep Downscaling of Precipitation
Authors: Mishra Sharma Sumanta Chandra , Mitra Adway
Published: March 2022

Downscaling is widely used to improve spatial resolution of meteorological variables. Broadly there are two classes of techniques used for downscaling i.e. dynamical downscaling and statistical downscaling. Dynamical downscaling depends on the boundary conditions of coarse resolution global models like General Circulation Models (GCMs) for its operation whereas the statistical model tries to interpret the statistical relationship between the high-resolution and low-resolution data (Kumar et. al. 2021). With the rapid development of deep learning techniques in recent years, deep learning based super-resolution (SR) models have been designed for image processing and computer vision, for increasing the resolution of a given image. But many researchers from other fields have also adapted these techniques and achieved state-of-the-art performance in various domains. To the best of our knowledge, only a few works exist that have used the super-resolution methods in climate domain, for deep downscaling of precipitation data.

These super-resolution approaches mostly use convolutional neural networks (CNN) to accomplish their task. In CNN when we increase the depth of the model then there is a chance of information loss and error propagation (Vandal et.al.2017). To reduce this information loss, we have introduced residual-based deep downscaling models. These models have multiple residual blocks and skip connections between similar types of convolutional layers. The long skip connections in the model helps to reduce information loss in the network. These models take as input, data that is pre-upsampled by linear interpolation, and then improve the estimates of the pixel values.

In our experiments, we have focused on downscaling of rainfall over Indian landmass (for Indian summer monsoon rainfall) and for a region in the USA spanning the southeast CONUS and parts of its neighboring states that are present between the longitude 700 W to 1000 W and latitude 240 N to 400 N. The precipitation data for this task is collected from the India Meteorological Department (IMD), Pune, India, and NOAA Physical Science Laboratory. We have examined our model's predictive behavior and compared it with the existing super-resolution models like SRCNN and DeepSD, which have been earlier used for precipitation downscaling. In the DeepSD model, we have used the GTOPO30 land elevation data provided by USGS along with the precipitation data as input. All these models are trained and tested in both the geographical regions separately and it is found that the proposed model performs better than the existing models on multiple accuracy measures like PSNR, Correlation Coefficient, etc. for the specific region and scaling factor.
Nitrous oxide emission peaks and distribution of nitrous oxide in the soil profile during rain events: A soil column experiment
Authors: Hansen Line Vinther , Brændholt Andreas , Tariq Azeem , Jensen Lars Stoumann , Bruun Sander
Published: March 2022

Nitrous oxide (N2O) emissions are notoriously variable at different spatial and temporal scales. As recognized in the literature, peaks in emissions of N2O occur after fertilization, precipitation and freeze-thaw events. Although the individual microbial processes have been extensively studied, the understanding of the underlying mechanisms behind the pulse emissions is still subject to many uncertainties. The N2O produced in connection with a rain event can either be entrapped in the soil matrix and be subject to N2O reduction or be released later when soil diffusivity increases as water infiltrate into the soil or evaporate.

To understand the mechanisms behind the observed flux emissions related to precipitation events, we are conducting a laboratory experiment to quantify the N2O movement in the soil. In 50 cm tall soil columns exposed to a simulated rain event, gas samples are extracted from the soil matrix at three depths via reinforced silicone tubes. At the surface, gas is sampled for flux estimates.

A common trigger of pulse emissions is a lowered soil oxygen content. Continuous monitoring of the soil oxygen with sensors at three depths provides measurements of O2 dynamics in the soil simultaneously with the N2O content. This can add to the understanding of how O2 relates to N2O production, reduction and movement. Tensiometers will additionally provide data on the soil water status during simulated precipitation events.

The experimental set-up can furthermore be used for studying the effects of other factors affecting N2O movement and emission in soil e.g., soil types, type of fertilizers, soil temperature etc. 

 

 
Have the 1999 Izmit-Düzce earthquakes influenced the motion and seismicity of the Anatolian microplate?
Authors: Iaffaldano Giampiero , Martin de Blas Juan , Calais Eric
Published: March 2022

In the current plate tectonics paradigm, relative plate motions remain unperturbed by temporal stress changes occurring during the seismic cycle, whereby the stress slowly built up along tectonic plate boundaries is suddenly released by rapid fault slip during earthquakes. However, the viscous resistance at the base of tectonic units of small size (i.e., microplates), and thus the torques needed to change their rigid motions, are significantly smaller than those needed for large size plates. In fact, a recent study that generates numerical simulations of synthetic microplates indicates that it is theoretically possible to link the temporal evolution of geodetically-observed microplate motions to the stresses associated with the seismic cycle.

Here we show that the rigid motion of the whole Anatolian microplate, measured using space geodetic techniques, was altered by the stress released during the 1999 Izmit-Düzce earthquakes, which ruptured along the North Anatolian Fault. This kinematic change requires a torque change that is in agreement with the torque change imparted upon the Anatolian microplate by the Izmit-Düzce coseismic stress release. This inference holds across realistic ranges of data noise and controlling parameters, and is not hindered by active deformation in western Anatolia. These results suggest the existence of a whole-plate kinematic signal associated with the stress released by large earthquakes.
Tomographic imaging of the magmatic system feeding the 2021 Cumbre Vieja eruption (La Palma, Canary Islands).
Authors: D'Auria Luca , Koulakov Ivan , Prudencio Janire , Cabrera-Pérez Iván , Ibáñez Jesús M. , Barrancos Jose , García-Hernández Rubén , Martínez van Dorth David , Padilla Germán D. , Przeor Monika , Ortega Victor , Hernández Pedro , Peréz Nemesio M.
Published: March 2022

The 2021 Cumbre Vieja surprised the worldwide volcanological community for its peculiar, unexpected features. Among these are the quite explosive character, even having the erupted magma a femic composition, the long duration (almost three months) and the huge erupted volume (more than 200 Mm3). The eruption was preceded by seismicity starting in Oct. 2017. However, the genuine precursory seismicity began only eight days before the eruption, with an evident upward migration of hypocenters. During the eruption, the seismicity mainly was concentrated at a subcrustal (10-15 km) and an upper mantle (20-25) depth.

Before and during the eruption, we collected a dataset of 11,349 earthquakes recorded from 7 October 2017 to 13 to December 2021 with 140,078 P wave and 155,231 S wave picks. We performed a high-resolution traveltime tomography, obtaining a three-dimensional P and S-wave velocity model up to a depth of about 25 km. The tomographic models evidence the presence of various interesting structures. At shallow depth (< 3 km), we identified a localized low-velocity anomaly interpreted as a volume of hydrothermal alteration. The Moho shows a complex geometry, with an upwelling beneath Cumbre Vieja volcano up to 10 km depth. Finally,  a large deep volume (> 400 km3) is characterized by high Vp/Vs values. This volume can be possibly related to the main magmatic reservoir feeding the eruption.

The tridimensional velocity model also allowed for a precise relocation of the seismicity, providing an interesting insight into the evolution of the eruption. Before eruption onset, magma ascended from about 10 km depth to the surface in a few days. The melt migration occurred along the contact between consolidated oceanic crust and altered hydrothermal material at shallow depth. We postulate that similar structural discontinuities could potentially drive the formation of new eruptive centres during future eruptions.
Cost-effective measures for climate change adaptation in a drought-prone area in eastern Germany
Authors: Zimmermann Beate , Hildmann Christian , Kruber Sarah , Witt Johanna Charlotte , Sturm Astrid , Hecker Lutz Philip , Wätzold Frank
Published: March 2022

Adaptation to climate change is an inevitable challenge in many regions. In our study area, which is located in the state of Brandenburg in eastern Germany, land use is increasingly affected by long-lasting soil moisture deficits in the vegetation period. It is therefore important to implement measures for water retention at the landscape scale that postpone and mitigate the severity of these drought periods. Our objective is to identify cost-effective measures in a manner that maximizes expected ecological benefits for available budgets. For this purpose, we combine a scientific analysis of the determinants of land surface temperature with site-specific cost calculations.

The distribution of land surface temperature serves as a proxy for environmental conditions that favor water retention and, as a consequence, provide a certain cooling effect during hot and dry periods. Landsat thermal images from the vegetation seasons of 2013 to 2020 were rescaled (min-max normalization) and used as the response variable for a Bayesian multilevel model. Several parameters of the physical environment such as land cover, forest and crop type, soil water holding capacity, canopy cover and degree of soil sealing were used as explanatory variables. In addition, an antecedent moisture index and potential evapotranspiration at time of satellite overpass were incorporated into the model. First results highlight the importance of land use and canopy cover for land surface temperature distribution. In general, the analysis enables the identification of overheated landscapes. Moreover, model predictions after hypothetical implementation of adaptation measures provide an ecological benefit assessment based on the cooling capacities. We also determine the costs of the different measures in a spatially differentiated manner. An integrated modeling procedure combines the results from the ecological and economic assessments.

In this contribution, we will present the results of the Bayesian modeling and discuss a first example of the cost-effectiveness analysis in an agricultural landscape.