bluuebunny/crossref_metadata_2025 huggingface dataset:
Reversing the European Trend Toward a Declining Land Carbon Sink?
Authors: Ellison David , Breidenbach Johannes , Petersson Hans , Korhonen Kari T. , Henttonen Helena , Wallerman Jörgen , Fridman Jonas , Mensah Alex Appiah , Gobakken Terje , Naesset Erik
Published: March 2021

The announced goal of reversing the European trend toward a declining land carbon sink has garnered much ink. Words can, however, be misleading. Annual additions/contributions (sinks) to the land carbon sink (stocks) from growing forest and increasing forest cover have slowed marginally in recent years. However, the existing European land forest sink (stocks) has (have) expanded continuously across most or all of the 20th century and on into the 21st. More importantly perhaps, EU Member states with significant long-term investments in the forestry sector have historically witnessed strong forest expansion and notmerely with the initiation of international attention to climate change mitigation through the UNFCCC negotiating and climate commitment framework. In this context, frequent assaults on forestry from multiple directions are cause for some bewilderment. We first highlight weaknesses in claims of increased forest use intensity and illustrate that forestry in the Nordic countries has a remarkably small and stable footprint over the 20th and 21st centuries. Addressing the second problem, however, understanding why such attacks occur in the first place, is more complex. Methodologically speaking, challenges to forestry should presumably be balanced by an understanding of the many human welfare benefits forests and the practice of forestry currently provide, as well as the costs of relinquishing those practices. Perhaps due to strong preferences among NGO’s and in parts of the academic community for natural, untouched, biodiverse forests, the benefits of forestry and forest resource use are consistently under-appreciated. Striking a balance between the desire for natural and biodiverse-rich forest environments on the one hand, and the climate change mitigation (and adaptation) benefits of forestry, forest resource use and substitution on the other is presumably a political and socio-economic necessity. The real question may be to what extent bias in favor of the “natural” may ultimately disrupt real, measurable progress toward effective climate change mitigation? Continuous, positive mitigation-related contributions to the growing European land cover sink (stocks), as well as to the global carbon budget (through annual net removals and substitution), have been and should remain the norm. These goals ultimately require an aggressive EU LULUCF strategy capable of fully mobilizing forest and forest resource use in favor of the goal of climate change mitigation (and adaptation).
Detecting Calving Events of Icebergs D-28 and B-49 using High Resolution Sentinel-1A SAR Data
Authors: Mitkari Kavita , Pallipad Jayaprasad , Putrevu Deepak , Misra Arundhati
Published: March 2021

Detecting iceberg calving events and subsequently tracking their movement is important because large icebergs can create problem in shipping and navigation. This study discusses two calving events that took place at 1) Amery ice shelf (East Antarctica) in September 2019 and 2) Pine Island Glacier’s floating ice shelf (West Antarctica) in February 2020. Though the calving that occurred in September 2019 does not have any impact on climate change, it is considered to be the most significant calving event on Amery ice shelf since 1963-64. The gigantic tabular iceberg officially named D-28 measures more than 600 square-miles. On the other hand, Pine Island is considered as the fastest retreating glaciers in Antarctica. This calving event gave rise to smaller icebergs, the largest of which was 120 square-miles, big enough to earn it a name: B-49. Though ice calving is a normal phenomenon at the ice shelves, the front of the glacier is stable if the rate of calving is in synchronization with the glacier’s forward flow. But, at Pine Island, the rate of disintegration has increased more than the glacier's speed to push the inland ice into Pine Island Bay. On-screen digitization approach of analysing time series dataset of glacier front positions is conventional, time consuming and subjective. To track the movement of icebergs D-28 and B-49, present study has detected rifts using canny edge detection filter and textural measures. We have utilized the Sentinel 1A SAR C-band (GRD) EW mode (Resolution (Rg x Az): 93 x 87 m and pixel spacing 40 x 40 m) images pertaining to the Amery ice shelf for Sep 2020-Mar 2020 and Pine Island Glacier with Pine Island Bay for Dec 2019-Mar 2020. All the images were processed for calibration (sigma0), speckle filtering (refined Lee), terrain correction (Range Doppler) and dB conversion using SNAP tool. Terrain correction has been performed using RAMP v2 DEM (200 m) and all the images have been projected to WGS 84/Antarctic Polar Stereographic projection and converted into dB. Through image interpretation, it is revealed that as of Mar 2020, iceberg D-28 has rotated almost 90 degrees anti-clockwise and drifted slightly northward away from Cape Darnley. In case of iceberg B-49, it is observed that the western portion of the calved ice, including the largest iceberg, has rapidly rotated out into Pine Island Bay, whereas the eastern half, including many smaller shards of ice, is following in similar fashion.
Predicting future energy and biodiversity trade-offs globally
Authors: Dunnett Sebastian , A Holland Robert , Taylor Gail , Eigenbrod Felix
Published: March 2021

Protected areas and renewable energy generation are key tools to combat biodiversity loss and climate change respectively. Over the coming decades, very large-scale expansion of renewable energy infrastructure will be needed to meet climate change targets, while simultaneously large-scale expansion of the protected area network to meet conservation objectives is planned. However, renewable energy infrastructure has negative effects on wildlife, and co-occurrence may mean emissions targets are met at the expense of conservation objectives. However, data limitations mean that the degree of likely future conflict of these two key land management objectives has not been fully assessed. Here, we address this gap by examining current and projected future overlaps of wind and solar photovoltaic installations and important conservation areas globally using new spatially explicit wind and solar photovoltaic data, and new methods for predicting future renewable expansion. We show similar levels of co-occurrence of important conservation areas and wind and solar installations as previous studies but also show that once area is accounted for previous concerns about overlaps in Northern Hemisphere may be largely unfounded, though are high in some high-biodiversity countries (e.g. Brazil). Future projections of overlap between the two land uses are generally lower than previously predicted using new data, with regional correlation coefficients peaking at -0.3418 and 0.2053, suggesting a low risk of future conflict. Our results show that the current and future overlap of the two land uses may not be as severe as previously suggested. This is important, as global efforts to decarbonise energy systems are central to mitigating against climate change and against the strong negative impacts of projected climate change on biodiversity.
A fully coupled spatially distributed hydrologic-hydrodynamic model for the Barotse Floodplain, Upper Zambezi
Authors: Chomba Innocent C. , Banda Kawawa , Winsemius Hessel , Makungu Eunice , Hughes Dennis , Eilander Dirk , Hrachowitz Markus , Nyambe Imasiku , Sichingabula Henry , Mataa Mulema , Chomba Machaya , Ellender Bruce , Ngwenaya Victoria
Published: March 2021

Floodplains play important roles in global hydrological and biogeochemical cycles, and many socioeconomic activities also depend on water resources in floodplains. Although considered as critical for the formation and preservation of floodplains, hydrology in floodplains has been hard to characterise. In recent years the demand for an understanding of the hydrological and hydrodynamic processes for the Barotse floodplains is ever increasing especially with the advent of climate change/variability, and expected upstream developments. Yet, the multi-way interactions between river flows, wetland inundation, and groundwater are complex, and poorly understood, compromising studying these changes. Most hydrological and hydrodynamic models applied for large-scale hydrological and inundation modelling lack an advanced floodplain-groundwater feedback mechanism, and thus may over predict or under predict inundation extent, depth, and downstream river flow. This is because groundwater re-infiltration and evaporation from the floodplains over a longer time scale than the flood process are not accounted for.  Hence, the main objective of this current study is to show the very first attempt to a fully coupled model for the Barotse floodplain. The hypothesis is that a fully coupled model will result in larger groundwater dynamics, a slower rise of inundation, and possibly a longer recession tail. To test this hypothesis, we setup two experiments; (i) in the first experiment, WFLOW runs and feeds upstream flows into LISFLOOD. This is sort of the classic approach, and similar to earlier studies, and also does not necessarily require a time-step based coupling; (ii) in the second experiment, WFLOW runs and feeds into Lisflood_FP, and Lisflood_FP then returns water into the WFLOW model. This an experiment where we re-infiltrate water into wflow and by doing so, let groundwater levels adapt so that additional reinfiltrated water, decrease the amount of flood water, increase groundwater levels more during the wet season, and provide a higher recession tail downstream. Our model environment and experiments are available through https://github.com/Innochomba/barotse.
re3data COREF – Enhancing the re3data service as a community-driven and trustworthy resource for research data repositories and portals
Authors: Weisweiler Nina , Elger Kirsten , Ulrich Robert , Witt Michael , Ferguson Lea Maria , Kindling Maxi , Kloska Gabriele , Binh Nguyen Thanh , Schabinger Rouven , Strecker Dorothea , Trofimenko Margarita , Vierkant Paul
Published: March 2021

re3data is the global registry for research data repositories. As of January 2021, the service lists over 2620 digital repositories across all scientific disciplines and provides an extensive description of repositories based on a detailed metadata schema (https://doi.org/10.2312/re3.008). A variety of funders, publishers, and scientific organizations around the world refer to re3data within their guidelines and policies, recommending the service to researchers looking for appropriate repositories for storage and discovery of research data. With over 750 entries the field of geosciences is one of the most strongly represented subject groups in the registry.

The re3data COREF project (Community Driven Open Reference for Research Data Repositories) started in January 2020 and receives funding from the German Research Foundation (DFG) for 36 months. With its main focus on the current project the presentation will outline the further professionalization of re3data and the provision of reliable and individualizable descriptions of research data repositories. This includes updates and revisions of the metadata schema, the advancement of the technical infrastructure as well as an enhanced overall (technical) service model concept to embed and connect the service within the research data landscape as a community-driven source and reference for trustworthy repositories.

In addition, outcomes from the first re3data COREF stakeholder survey and workshop held in November 2020 will be presented, introducing diverse use cases of the re3data service and examples for the reuse of its metadata. The presentation will address how re3data currently interlinks with external parties and how more advanced options for easier and trustworthy integration of third-party information can be facilitated.
Conflicting interests over hydropower: Identifying and representing stakeholder perspectives on new projects using causal mapping. 
Authors: Voegeli Guillaume , Finger David Christian
Published: March 2021

The evaluation of the stakeholders’ perception of new hydropower projects is essential for assessing public acceptance, ensuring local involvement, and identifying feasible and desirable changes towards sustainable development. This study uses the concept of causal diagrams (CD) to identify the individual perspectives of stakeholders of two new hydropower projects, one in Switzerland (Val d’Ambra project) and one in Iceland (Hvammvirkjun project). For this purpose, semi-structured interviews with relevant stakeholders were conducted, which were then categorized into 5 interest groups. Using the software Atlas.ti, we identified and sequenced the perceived causality of impact pathways of the two projects. The results are exposed in two series of 10 topical causal networks, and two aggregated diagrams. For each case, CDs expose the complexity of multi-sequenced causalities between elements of a very heterogeneous nature, as expected and reported by stakeholders. This approach enables the identification of inter- and intra-group conflicting perspectives, and perceived uncertainties, concerning both subjectives matters along with much more tangible and predictable aspects. Our method enables the identification of areas where further research or better transfer of information between stakeholders is required. It also exposes how hydropower impacts can differ in time and space, when in one case study, intracommunity tensions and conflicts were identified at the earliest project stage, along with psychological distress of some local residents. Based on the presented CD, we conclude that this method can facilitate communication and problem-solving in complex social-environmental situations amid multiple stakeholder categories, which heterogeneity should not be underestimated.

This research has been published in Energy Research and Social Science:

https://www.sciencedirect.com/science/article/pii/S2214629620304473
Similarities of the Scotia and Caribbean Plates: Implications for a common plate tectonic history?!
Authors: Burmeister Christian , Wintersteller Paul , Meschede Martin
Published: March 2021

The active volcanic arcs of the Scotia Plate and Caribbean Plate are two prominent features along the otherwise passive margins of the Atlantic Ocean, where subduction processes of oceanic crust is verifiable. Both arcs have been, and continue to be, important oceanic gateways during their formation. Trapped between the large continental plates of North- and South America, as well as Antarctica, the two significantly smaller oceanic plates show striking similarities in size, shape, plate margins and morphology, although formed at different times and locations during Earth’s history.

Structural analyses of the seafloor are based on bathymetric datasets by multibeam-echosounders (MBES), including data of the Global Multi Resolution Topography (GMRT), Alfred Wegener Institute (AWI), MARUM/Uni-Bremen, Geomar/Uni-Kiel, Uni-Hamburg and the British Antarctic Survey (BAS). Bathymetric data were processed to create maps of ocean floor morphology with resolution of 150-250 meters in accuracy. The Benthic Terrain Modeler 3.0 (BTM), amongst other GIS based tools, was utilized to analyse the geomorphometry of both plates. Furthermore, we used the bathymetric datasets for three-dimensional modelling of the seafloor to examine large-scale-structures in more detail.

The modelling of ship-based bathymetric datasets, in combination with the GEBCO 2014 global 30 arc-second interval grid, included in the GMRT bathymetric database, delivered detailed bathymetric maps of the study area. With the help of the fine- and broad-scale bathymetric position index (BPI), comparable to the topographic position index (Weiss, 2001), we present the first detailed interpretation of combined bathymetric datasets of the Scotia Sea, including the entire Scotia Plate and adjacent areas, such as the East Scotia Plate. We identified typical morphological features of the abyss, based on the determination of steep and broad slopes, ridges, boulders, flat plains or flat ridge tops and depressions in various scales. Additional data analyses of gravimetric and magnetic properties of the crust should help to understand the plate tectonic history of both areas in more detail.

References:
Ryan, W. B. F; Carbotte, S.M.; Coplan, J.; O'Hara, S.; Melkonian, A.; Arko, R.; Weissel, R.A.; Ferrini, V.; Goodwillie, A.; Nitsche, F.; Bonczkowski, J. and Zemsky, R. (2009): Global Multi-Resolution Topography (GMRT) synthesis data set, Geochem. Geophys. Geosyst., 10, Q03014, doi:10.1029/2008GC002332.

Walbridge, S.; Slocum, N.; Pobuda, M.; Wright, D.J. (2018): Unified Geomorphological Analysis Workflows with Benthic Terrain Modeler. Geosciences 2018, 8, 94. doi: 10.3390/geosciences8030094

Weiss, A. D. (2001): Topographic Positions and Landforms Analysis (Conference Poster). Proceedings of the 21st Annual ESRI User Conference. San Diego, CA, July 9-13.
Topological mapping: new method to map, analyze, and visualize humanistic data in the Arctic
Authors: Westerveld Levi
Published: March 2021

Maps have always played a central role in the analysis, visualization, and communication of environmental scientific data. In recent years, a growing number of social scientists have turned to mapping and Geographic Information Science (GIS) tools, to visualize and map human experiences, including in the Arctic. At the same time, social and theoretical critiques of GIS as a tool wielded chiefly by and for those in power have increased awareness of its limitations, particularly for studying human perceptions, experiences, and the meanings of place. Indeed, many places tied to human experience, such as emotions, sounds, or memories, cannot be mapped in a conventional GIS: they do not fit the rigidity of the Cartesian grid. They may lack coordinates, or simply have ambiguous boundaries. In this presentation, I discuss how a new mapping methodology – topological mapping – developed in the context of Holocaust research, can be applied for integrating traditional knowledge, or human experience, in Arctic geographical research. This new method pushes the field of GIScience in new directions, providing new opportunities for trans-disciplinary research, which better integrates humanistic data in mapping for analysis and communication. Using examples from using topological mapping whilst working with Saami reindeer herders youth, I demonstrate the potential for this new mapping method in the Arctic.  
Analysis of factors affecting the Spatial Distribution of co-seismic landslides triggered by the 2011 (Mw 6.9) Sikkim earthquake
Authors: Kumar Saurav , Aniruddha Sengupta
Published: March 2021

The Himalayan region is known as an earthquake-triggered landslides prone area. It is characterized by high seismicity, large relative relief, steep slopes, and dense precipitation. These seismically triggered landslides are likely to affect substantial societal impacts, including loss of life, damage to houses, public buildings, various lifeline structures like highways, railways tracks, etc. Further, they obstruct post-earthquake emergency response efforts. A past study by Martha et al. 2014 reported that an earthquake of Mw 6.9 in 2011 triggered 1196 landslides in Sikkim which is a part of the eastern Himalayas. The slope failure events are controlled by several factors, which can be grouped into four main classes: seismology, topography, lithology, and hydrology. Each class contains several sub-factors. Having in-depth knowledge of these factors and their influence on the density of landslide events in the affected area due to the 2011 Sikkim earthquake is essential to realize the level of threat of co-seismic landslide due to future earthquakes. Eight landslide controlling factors is considered in this analysis including peak ground acceleration (PGA), slope, aspect, elevation, curvature, lithology, distance from rivers, and topographic wetness index (TWI). Further, the frequency ratio model using the GIS framework is applied to evaluate the contribution of each landslide controlling factor to landslide occurrence. Scatter plots between the number of landslides per km2 (LN) and percentage of landslide area (LA) and causative factors indicate that distance from the river, slope angle, and PGA are the dominant factors that control the landslides. The results of the above analysis showed that the majority of co-seismic landslides occurred at slope >30°, preferably in East, Southeast, and South directions and near river within a distance of 1500 m. The detailed study of interactions among these factors can improve the understanding of the mechanisms of co-seismic landslide occurrence in Sikkim and will be useful for producing a co-seismic landslide susceptibility map of the area.
Machine Learning Methods to Infer Precipitation Phase from Temperature and Moisture Profiles
Authors: Brunet Dominique , Quinto John Rafael Ranieses
Published: March 2021

The phase of falling precipitation can have a large societal impact for both hydrology (snow storage, rain-on-snow events), meteorology (snowstorms, freezing rain) and climate (snow albedo feedback). In Canada, many surface weather stations report precipitation information in the form of total precipitation (liquid-equivalent), but very few weather stations directly report snow. Thus, precipitation phase must be inferred from ancillary data such as temperature and moisture. Each scientific community has developed its own tool for the determination phase in the absence of direct observations: from simple rules based on air temperature, dew point temperature or wet bulb temperature to sophisticated microphysics schemes passing by methods based on the discrimination of features extracted from vertical temperature profiles. With the recent advances of machine learning, there is an opportunity to investigate another set of methods based on deep neural networks.

Using ERA5 and ERA5-Land model re-analyses as the reference, we trained several recurrent neural networks (RNN) on vertical profiles of temperature and moisture to infer the snow fraction – the ratio of solid precipitation to total precipitation. Since precipitation phase (solid, liquid or mixed) was not directly available in the model re-analysis, we defined it using two thresholds: snow fraction of less than 5% for liquid, snow fraction of more than 95% for solid phase, and mixed phase for everything in between. The best performing neural network for regressing snow fraction is found to be a Gated Recurrent Unit (GRU) RNN using profiles up to 500 hPa above the surface of both temperature and relative humidity. A slight decrease in performance is observed if profiles up to 700 hPa are used instead. A feature experiment also reveals that the performance is significantly better when using both temperature and moisture profiles, but it does not really matter what type of moisture observations are used (either dew point spread, wet bulb temperature or relative humidity). For classifying precipitation phase, the balanced accuracy is over 90%, clearly outperforming the implementation of Bourgouin’s method used operationally in part of Canada. Compared with the K-Nearest Neighborhood (KNN) method trained on surface observations only, it is seen that the greatest gain in performance for GRU-RNN is when the surface temperature is close to zero degrees Celsius.

These preliminary results indicate the great potential of the proposed algorithm for determining snow fraction and precipitation phase in the absence of direct observations. The proposed algorithm could potentially be used for inferring snow fraction and precipitation phase in several applications such as (1) precipitation analysis for forcing hydrological models, (2) weather nowcasting, (3) weather forecast post-processing and (4) climate change impact studies.

 
A Standardized Database of Marine Isotope Stage 5a and 5c Paleo-Shoreline Indicators
Authors: Thompson Schmitty B. , Creveling Jessica R.
Published: March 2021

Reconstructions of global mean sea level (GMSL) through interstadials such as Marine Isotope Stages (MIS) 5a and 5c provide important constraints on the rates of growth and collapse of major ice sheets during warm periods analogous to future climate projections. These reconstructions rely upon precisely dated geomorphic and sedimentological indicators for past sea level whose present elevations are complicated by tectonics and glacial isostatic adjustment (GIA). Compilations of MIS 5a and 5c paleo-sea level indicators that covering a wide geographic range can be used to minimize misfit with glacial isostatic adjustment models and thereby quantify and refine the convolved contribution of GMSL to the present elevation of paleo-shoreline indicators. Here we present a global compilation of previously published Marine Isotope Stages 5a and 5c local sea level indicators from 39 sites covering three main regions: the Pacific coast of North America, the Atlantic coast of North America and the Caribbean, and far field. We describe the standardized entry of these data into the World Atlas of Last Interglacial Shorelines (WALIS) database. Each entry within the MIS 5a and 5c WALIS database reproduces from the primary literature the indicator elevation, indicative meaning, and geochronology, along with a comprehensive overview of the literature for each site. While MIS 5a and 5c indicators sites are geographically widespread, these data are also patchy and preferentially represent the North American continent and the Caribbean and, hence, regions intermediate and far afield of the contemporaneous ice sheets. While this dataset will support future refinements to MIS 5a and 5c GMSL reconstructions arising from GIA modeling, it also motivates further data collection.
A detailed look at monoterpene oxidation reactions: results from the CERVOLAND field campaign and MCM modelling
Authors: Reijrink Nina , Lahib Ahmad , Bouzidi Hichem , Duncianu Marius , Perraudin Emilie , Flaud Pierre-Marie , Villenave Eric , Williams Jonathan , Tomas Alexandre , Dusanter Sébastien
Published: March 2021

Atmospheric oxidation reactions can be studied in the field, in the lab and by modelling, with each methodic approach having advantages and issues. The main drawback for field experiments is that both chemical and non-chemical processes (emission, advection, vertical dilution, etc.) can simultaneously impact the chemical composition of ambient air, making it difficult to assess their respective contributions. For this purpose, a mobile atmospheric chamber (DouAir) has been developed to trap ambient air at a measurement site and to investigate the chemistry taking place in this isolated air mass. Since the environment within the chamber is controllable, oxidation processes can be measured and modelled with relative ease, so that the underlying chemistry can be better understood.

During July 2018 the DouAir chamber was brought to the Landes Forest in the southwest of France for the CERVOLAND field campaign (Characterisation of Emissions and Reactivity of Volatile Organic compounds in the LANDes forest). The reactor was used to trap real air masses coming from the surrounding forest - consisting mainly of Pinus pinaster trees - and the captured air was subsequently oxidised within the chamber. Different oxidation regimes were studied: dark oxidation, light oxidation by natural sunlight and light oxidation by artificial UV light with a known spectrum. Oxidation processes within the chamber were monitored by a variety of online instruments, including PTR-ToF-MS (for VOCs), PERCA (for peroxy radicals), O3 and NOx analysers, and CPC (for particles).

Here, we present the experimental results from the CERVOLAND field campaign under different oxidation conditions and the results from the 0-D modelling of these experiments using MCM. The focus is on measured and modelled monoterpene oxidation products and possible explanations for measurement-model discrepancies.
Post-seismic deformation related to the 2016 central Italy seismic sequence from GPS displacement time-series
Authors: Mandler Eugenio , Belardinelli Maria Elina , Serpelloni Enrico , Anderlini Letizia , Gualandi Adriano , Pintori Francesco
Published: March 2021

The 2016-2017 Central Italy earthquake sequence was characterized by three main events striking the central Apennines between August 2016 and October 2016 with a Mw ∈ [5.9 to 6.5], plus four earthquakes occurring in January 2017 with a Mw ∈ [5.0; 5.5]. Here we study 85 Global Positioning System (GPS) stations active during the post-seismic phase in a region within a radius of 100 km around the epicentral area, including near and far-field domains. We separate the post-seismic deformation from other, mainly seasonal, deformation signals present in ground displacement time-series via a variational Bayesian Independent Component Analysis (vbICA) technique. Excluding the postseismic transient signal, we found that all the other components are due to hydrological processes, and found no evidence of pre-seismic deformation signals with a spatial and temporal pattern that can be ascribed to a precursory deformation. We study the role played by afterslip on the main structures activated during the co-seismic phase, and we infer the activation during the post-seismic phase of the Paganica fault, which is located further south of the 2016-2017 epicenters and did not rupture during the co-seismic phase. We investigate an aseismic activation of the ∼ 2 − 3 km thick subhorizontal layer of seismicity, which bounds at depth the SW-dipping normal faults where the mainshocks nucleated, and which has been interpreted as a shear zone. Moreover we consider the possibility that the shear zone marks the brittle-ductile transition including the viscoelastic relaxation of the lower crust and upper mantle as a driving mechanism of the post-seismic displacement. However, neither afterslip nor viscoelasticity can fully explain the observations alone: the former is capable of satisfactorily explaining only the data in the epicentral area but it generally underestimates the displacement in the far-field domain; the latter cannot simultaneously explain the displacement observed in the near-field and far-field domains. Hence we infer a mixed contribution of these two mechanisms. 
Geomorphic Apophenia: Inferring meaning where there could be none?
Authors: Coulthard Tom
Published: March 2021

Apophenia describes the experience of seeing meaningful patterns or connections in random or meaningless data. Francis Bacon was one of the first to identify its role as a "human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds". Since then, experiments using streams of randomly generated binary sequences show a propensity for people to believe random data fluctuates more than it actually does. A more mainstream example of this is gamblers fallacy, where lucky or unlucky streaks are identified in the random selection of a roulette wheel. Furthermore, humans can also be influenced by a pre-existing ideas or a narrative that they then transpose into their findings leading to tending to support a hypothesis instead of disproving (confirmation bias).  

As much of geomorphological science involves the interpretation of data, we argue that the persuasiveness of a narrative and human difficulties in recognizing genuinely random data could lead to apophenia. This presentation examines where apophenia might affect geomorphology, using examples from sediment stratigraphy, signal shredding, river meandering and the numerical modelling of landscape systems. In particular, we focus on how seductive it can be to link changes in landscape to drivers when there are potentially hazardous gaps in the data we are using.

In Geomorphology correlation has for long been substituted by causation. However, with emerging data rich methods including structure from motion, seismology, remote sensing and numerical modelling, former ‘classic’ techniques of qualitative interpretation can give way to quantitative hypothesis testing.
Three-dimensional distribution of biomass burning aerosols from Australianwildfires revealed by TROPOMI satellite observations
Authors: Lemmouchi Farouk
Published: March 2021

The quantification of the abundance of particulate matter in the atmosphere has a great societal importance, as they directly impact the environment and Earth climate. Aerosols modify the radiative budget of the planet by scattering the sun radiation and preventing part of it from reaching the Earth surface . Depending on the vertical distribution of aerosols in the atmosphere, they may also modify precipitation rates since they act as cloud condensation nuclei. When located near the surface, aerosols are the most harmful air pollutants causing chronic diseases and premature deaths of millions of people everyyear around the world (WHO 2018). Aerosols can directly impact the economy by e.g., transport disruption or health care costs.

Satellite measurements offer a great potential for observing aerosol distribution in the atmosphere from the regional to the global scale. However, these measurements are mostly done in two dimensions (2D): horizontal distributions of aerosol optical depth (AOD) by passive sensors as MODIS or latitudinal transects of vertical profiles of aerosol backscatter spaced in longitude by about 2000 km as done by the CALIOP spaceborne lidar. Recently, horizontal maps of mean aerosol layer altitudes are also retrieved by analyzing the radiation spectra. However, the full 3D distribution of aerosols at daily scale has been only observed for coarse particles such as desert dust from the analysis of thermal infrared spectra from the IASI sensor (Cuesta et al., 2015, 2020). In the present work, we have extended the retrieval of the 3D distribution for fine aerosols for the first time, applying the approach on the biomass burning aerosol emitted from Australian major wildfires in December 2019. For this, we have analyzed the spectrum of reflectance at the oxygen A-band around 760 nm together with some part of the visible spectrum measured by the TROPOMI sensor onboard the Sentinel 5-Precursor satellite. Since these measurements are done in the near infrared and visible, they are sensible to fine aerosols and oxygen absorption in the A-band provides information on the vertical distribution of these particles. The retrieval is based on a Tikhonov-Philips altitude-dependent regularisation which adapts the constraints iteratively to each observed scene as done by Cuesta et al., (2015). In the current presentation, we will present the first retrievals of the 3D distribution of biomass burning aerosols for cloudfree conditions. We compare our TROPOMI-derived 3D distributions with MODIS 2D AOD maps, AERONET AOD retrievals and CALIOP vertical profile transects. Finally, we analyse the 3D pathways of transport followed by these biomass burning aerosols during these events, based on our new retrieval.
Ground displacement over Petrinja area caused by earthquake M6.2: interdisciplinary analysis of geodesy and geology based on analysis from SAR Sentinel-1 data
Authors: Bjelotomić Oršulić Olga , Korbar Tvrtko , Markovinović Danko , Varga Matej , Bašić Tomislav
Published: March 2021

At the very end of the year 2020, at 29th of December, hazard earthquake of M=6.2 hit near Petrinja, at NW of Croatia. Earthquake have been felt in a circumstance of a 400 kilometers, leaving in an epicenter vicinity inconceivable damage, devastated towns and obstructed lives. In order to obtain the first emergency crisis numbers over the impact of the earthquake on a ground motion, we have analyzed open satellite radar images of Copernicus Sentinel-1 along with the seismic faults. Multiple spatio-temporal Copernicus Sentinel-1 C-SAR images were used and processed for the differentiating the before and after earthquake state of the art. This presentation shows the results of the SAR conducted analysis, with the results of ground displacement in vertical up-down and horizontal east-west direction. The results show the vertical ground displacement to extent of -12 cm at southern area to +22cm at north-west part of a wide area covered by the earthquake impact regarding the epicenter. The horizontal displacement is detected in range between 30 cm towards west and 40 cm towards east is detected around the epicenter area, and +/-5cm horizontal displacement over a wider affected area indicate a spatial extent and hazardous impact the mainshock event made. The SAR results were verified by including the analysis over one station from the national positioning reference frame CROPOS. Accordingly, we obtained matching results of 5 cm easting shift and -3 cm subsidence on Sisak GNSS CROPOS station which coressponds to our SAR findings. Furthermore, geological interepretation of new findings is given based on results detecting Pokupsko and Petrinja fault.
Coseismic surface "conjugate" faulting of the 29 December 2020., MW 6.4, Petrinja earthquake (Sisak-Moslavina, Croatia)
Authors: Tondi Emanuele , Blumetti Anna Maria
Published: March 2021

We provide here a first-hand description of the coseismic surface effects caused by the Mw 6.4 Petrinja earthquake that hit central Croatia on 29 December 2020. This was one of the strongest seismic events that occurred in Croatia in the last two centuries. Field surveys in the epicentral area allowed us to observe and map primary coseismic effects, including geometry and kinematics of surface faulting, as well as secondary effects, such as liquefaction, sinkholes and landslides. The resulting dataset consists of homogeneous georeferenced records identifying 222 observation points, each of which contains a minimum of 5 to a maximum of 14 numeric and string fields of relevant information. The earthquake caused surface faulting defining a typical ‘conjugate’ fault pattern characterized by Y and X shears, tension cracks (T fractures), and compression structures (P shears) within a ca. 10 km wide, right-lateral strike-slip fault zone (i.e. the Petrinja Fault Zone, PFZ). We believe that the results of the field survey provide fundamental information to improve the interpretation of seismological, GPS and InSAR data of this earthquake. Moreover, the data related to the surface faulting may impact future studies focused on earthquake processes in active strike-slip settings, integrating the estimates of slip amount and distribution in assessing the hazard associated with capable transcurrent faults.
Towards reproducible pluvial flood simulation in urban areas with TELEMAC-2D
Authors: Pilz Tobias
Published: March 2021

The megacity of Lagos, Nigeria, is subject to recurrent severe flood events as a consequence of extreme rainfall. In addition, climate change might exacerbate this problem by increasing rainfall intensities. To study the hazard of pluvial flooding in urban areas, several complex hydraulic models exist with a high demand in terms of required input data, manual preprocessing, and computational power. However, for many regions in the world only insufficient local information is available. Moreover, the complexity of model setup prevents reproducible model initialisation and application. This conference contribution addresses these issues by an example application of the complex hydrodynamic model TELEMAC-2D for the city of Lagos. The complex initialisation procedure is simplified by the new package ‘telemac’ for the statistical environment R. A workflow will be presented that illustrates the functionality of the package and the use of publicly available information, such as free DEMs and Openstreetmap data to cope with the problem of insufficient local information. By further analysis and visualisation procedures along the workflow the increasing hazard of pluvial flooding for Lagos is shown. The workflow makes model initialisation, application, and the analysis of results reproducible and applicable to other regions with a relatively low need for manual user interventions and without additional software other than R and TELEMAC-2D.
Methane emissions from Scots pine and Norway spruce in the spring
Authors: Tenhovirta Salla , Kohl Lukas , Koskinen Markku , Patama Marjo , Pihlatie Mari
Published: March 2021

Plant shoots can emit methane (CH4) which is produced by an unknown aerobic, non-enzymatic process within the plant. Only a few publications report shoot CH4 fluxes outside a laboratory setting, and those of boreal trees come to contradictory results (Machacova et al., 2016; Sundqvist et al., 2012).  Resolving the CH4 fluxes of boreal trees is needed in order to understand the role of boreal forests in the global methane budget.

We conducted shoot chamber measurements on Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) between April and May 2019, to find out if the shoots of boreal conifer trees are a source of aerobic CH4 during the early growing season. The experiment was done with potted 2-3 year old nursery saplings in a common garden experiment, to enable regular measurements over a period of six weeks. CH4 fluxes were measured 2-3 times per day, on two days per week from seven saplings (four P. sylvestris and three P. abies, respectively). We also conducted two around the clock campaigns where we measured the saplings hourly throughout the day and night. The CH4 and carbon dioxide (CO2) exchange were quantified with a portable LGR online greenhouse gas analyser connected in closed loop to custom-made, transparent shoot chambers. Photosynthetically active radiation (PAR) was measured concurrently with a PP Systems EGM-4 monitor.

Our measurements show emissions of CH4 from both tree species, ranging from 0.25 to 7.64 and -0.45 to 6.42 g-1 needle dry weight h-1 (inter-quartile range) from P. sylvestris and P. abies shoots, respectively. The shoot CH4 emissions from both species correlated positively with PAR. During the around the clock measurements the emissions showed a diurnal pattern. Our experiment demonstrates that the shoots of both P. sylvestris and P. abies can be a source of CH4 in the spring and that the source process is likely driven by solar irradiation.

 

References

Machacova, K., Bäck, J., Vanhatalo, A. et al. 2016. Pinus sylvestris as a missing source of nitrous oxide and methane in boreal forest. Scientific Reports, 6(September 2015), 1–8.

Sundqvist, E., Crill, P., Mlder, M. et al. 2012. Atmospheric methane removal by boreal plants. Geophysical Research Letters, 39(21), 10–15.
Modulation of Ion Pitch Angle in the Presence of Large-amplitude, Electromagnetic Ion Cyclotron (EMIC) Waves: 1-D Hybrid Simulation
Authors: Ti Shuo , Chen Tao , Yao Jiansheng
Published: March 2021

Large-amplitude electromagnetic ion cyclotron (EMIC) waves induce unique dynamics of charged particle movement in the magnetosphere. In a recent study, modulation of the ion pitch angle in the presence of large-amplitude EMIC waves is observed, and there lacks a good explanation for this phenomenon. We investigate this modulation primarily via a 1-D hybrid simulation model and find that the modulation is caused by the bulk velocity triggered by large-amplitude EMIC waves. Affected by the bulk velocity, the number density of ions will enhance around pitch angle . Beyond that, the ion pitch angle is also modulated by the EMIC waves, and the modulation period is half of the EMIC waves' period. In addition, parameters that affect ion pitch angle modulation, including the wave amplitude, ion energy, ion species, and wave normal angle, are studied in our work.
Unravelling the thermal state of the southern Central Andes and its controlling factors
Authors: Rodriguez Piceda Constanza , Scheck-Wenderoth Magdalena , Bott Judith , Gomez Dacal Maria Laura , Pons Michaël , Prezzi Claudia , Strecker Manfred
Published: March 2021

The Andes represent the modern type area for orogeny at a non-collisional, ocean-continent convergent margin. Subduction geometry, tectonic deformation, and seismicity at this plate boundary are closely related to lithospheric temperature distribution in the upper plate. Despite recent advances in the assessment of the thermal state of the Andean lithosphere and adjacent regions derived from geophysical and geochemical studies, several unknowns remain concerning the 3D temperature configuration at lithospheric scale. In particular, it is not clear how both, the configuration of the continental overriding plate (i.e., its thickness and composition) and the variations of the subduction angle of the oceanic Nazca plate influence thermal processes and deformation in the upper plate. To address this issue, we focus on the southern segment of the Central Andes (SCA, 29°S-39°S), where the Nazca plate changes its subduction angle between 33°S and 35°S from the Chilean-Pampean flat-slab zone (< 5° dip, 27-33°S) in the north to a steeper sector south of 33°S (~30° dip). Additionally, the overriding plate exhibits variations in the crustal geometry and density distribution along- and across-strike of the subduction zone. We derived the 3D lithospheric temperature distribution and the surface heat flow of the SCA from the inversion of S-wave velocity to temperatures and calculations of the steady-state conductive thermal field. The configuration of the region – concerning both, the heterogeneity of the lithosphere and the slab dip – was accounted for by incorporating a 3D data-constrained structural and density model of the SCA into the workflow. We conclude that the generated thermal model allows us to evaluate how mantle thermal anomalies and first-order structural and lithological heterogeneities in the lithosphere, observed across and along-strike of Andean orogen, affect the thermal field of the SCA and thus the propensity of the South American lithosphere to specific styles in deformation. In addition, our results are useful to constrain thermo-mechanical simulations in geodynamic modelling and therefore, contribute to a better understanding of the present-day rheological state of the Andes and adjacent regions.
How does convective self-aggregation affect precipitation extremes?
Authors: Da Silva Nicolas , Shamekh Sara , Muller Caroline , Fildier Benjamin
Published: March 2021

Convective organisation has been associated with extreme precipitation in the tropics. Here we investigate the impact of convective self-aggregation on extreme rainfall rates. We find that convective self-aggregation significantly increases precipitation extremes, for 3-hourly accumulations but also for instantaneous rates (+ 30 %). We show that this latter enhanced instantaneous precipitation is mainly due to the local increase in relative humidity which drives larger accretion efficiency and lower re-evaporation and thus a higher precipitation efficiency.

An in-depth analysis based on an adapted scaling of precipitation extremes, reveals that the dynamic contribution decreases (- 25 %) while the thermodynamic is slightly enhanced (+ 5 %) with convective aggregation, leading to lower condensation rates (- 20 %). When the atmosphere is more organized into a moist convecting region, and a dry convection-free region, deep convective updrafts are surrounded by a warmer environment which reduces convective instability and thus the dynamic contribution. The moister boundary-layer explains the positive thermodynamic contribution. The microphysic contribution is increased by + 50 % with aggregation. The latter is partly due to reduced evaporation of rain falling through a moister near-cloud environment (+ 30 %), but also to the associated larger accretion efficiency (+ 20 %).

Thus, the change of convective organization regimes in a warming climate could lead to a much more different evolution of tropical precipitation extremes than expected from thermodynamical considerations. Improved fundamental understanding of convective organization and its sensitivity to warming, as well as its impact on precipitation extremes, is hence crucial to achieve accurate rainfall projections in a warming climate.