bluuebunny/crossref_metadata_2025 huggingface dataset:
Using art to enliven research on deadwood
Authors: Ferrando Jorge Nerea , Shannon Vicky , Clark Joanna , Shaw Liz , Vanguelova Elena , Morison James
Published: March 2022

Often scientists think of creating visuals like graphs, tables, and charts to better convey their research or make it more appealing to a broader public. However, some data or scientific concepts are complex and difficult to grasp. Instead, art is a universal language. This has led to a tremendous growth in data visualisation using art in the last decade.

At the University of Reading, a team of scientists are collaborating with environmental scientist and visual artist, Nerea Ferrando, to enliven the important story of deadwood for forest functioning. Deadwood refers to trees, or parts of a tree, that are dying or have died. Research in this field is increasingly showing that deadwood stabilises forests, sustains productivity, stores carbon, and provides food and a home for thousands of species, including invertebrates, fungi, as well as birds and mammals. Yet, despite its enormous ecological significance, deadwood remains one of the most threatened habitats in managed forests. Its amount, quality, and diversity is usually heavily reduced by forestry as a common strategy to control pests or make sites accessible.

The artist is creating a series of works to bring to light this less visible part of the forest and help communicate specific aspects of the research findings, such as its unrecognized role in the carbon cycle, the impact of deadwood on biodiversity, or exposing contradictory views on best management practices.

Ultimately, the science-artwork seeks to promote consciousness and awareness of the value of deadwood and the benefits it provides. Raising awareness is essential because, to date, deadwood continues to receive little attention and the adoption of management strategies that create or maintain a variety of deadwood are needed to protect forest health.
Understanding extreme diurnal convection over Lake Victoria from a convection permitting regional climate simulation
Authors: Glazer Russell , Coppola Erika
Published: March 2022

The Lake Victoria Basin is home to largest freshwater lake (Lake Victoria; LV) in Africa and second largest in the world. Each year hundreds of fisherman are lost on LV during intense night-time thunderstorms. LV is an essential component of the local economy while at the same time being one of the most hazardous lakes in the world. Despite this, until recently, understanding of the processes contributing to heavy rainfall events was very limited. In this study we present a 10-year (2005-2015) convection permitting (3km grid-spacing) simulation (CPS) of the Lake Victoria Basin using the RegCM version 4.7.0. A lake model is utilized in order to couple the lake regions with RegCM, which has been shown to be of great importance for simulating a realistic lake surface temperature (LST) and precipitation over LV. Mesoscale circulations associated with the diurnal cycle over LV are an important driver of intense night-time thunderstorms. An analysis of the diurnal rainfall cycle over LV shows that the CPS well represents the timing of nocturnal rainfall over the lake which is associated with a strong landbreeze, however the daytime peak in rainfall over the land surrounding the lake is too early relative to observed data. The temporal spectrum of lake rainfall shows a dominance in diurnal frequencies while intraseasonal timescales show only a very weak signal. Extreme nocturnal rainfall events exceeding 2STD of the lake rainfall timeseries are composited and separated for further analysis. These events show a clear migration from the previous daytime peak in rainfall over land, westward onto the lake during the night. To understand these diurnal precipitation events we explore mechanisms which may play a role in the events such as, the strength of the lake-landbreeze circulation, and convective instability.
Volcano-tectonic interactions within two recently discovered submarine volcanic fields: Implication for geodynamics in the Comoros
Authors: Boymond Pierre , Feuillet Nathalie , Thinon Isabelle , Scholtès Luc , Leroy Sylvie , Rusquet Anaïs , Masquelet Charles , Jacques Eric ,   SISMAORE team
Published: March 2022

The birth of a new volcano offshore the eastern coast of Mayotte, one of the oldest volcanic island in the Comoros archipelago rose questions about the origin of the volcanism in this area. The volcano-tectonic context of this region is poorly known mainly because high-resolution marine data was missing. Here we present new marine geophysical data (bathymetry, backscatter and seismic reflexion data) acquired between December 23 2020 and February 11 2021 during the SISMAORE cruise (Thinon et al., 2021) in the framework of the French ANR COYOTES project. The high-resolution multibeam bathymetric and backscatter data reveal the existence of two submarine volcanic provinces we named N’Droundé and Mwezi (Thinon et al., 2022). In these provinces, we identified faults scarps, volcanic structures, lava flows and flat-top sedimentary domes on the seafloor. Those volcanic and tectonic features are very well preserved in the morphology and very reflective in the backscatter attesting that they are recent and probably active. Several seismic reflection profiles crosscut those structures. They reveal that the sedimentary layers are cut by faults and intruded by sills and dykes. We showed that the recent deformations of the seafloor such as flat-topped domes and grabens are promoted by those intrusions. The recent deformation of the sediments accommodating the magmatic intrusions are used as indirect markers to establish a relative chronology of magmatic activity in the two volcanic provinces. We showed that the magmatism is older in the N’Droundé volcanic province, near Grande Comore than in Mwezi’s, North-East of Anjouan. We also showed from the analysis of sills and dykes in the sedimentary cover that the magmatism intruded during two non-concurring episodes.

Those volcano-tectonic features align in a mean NW-SE direction and may have likely emplaced in a NE-SW extensional stress field. At a smaller spatial scale, some diking-induced graben form swarms of different directions implying local perturbation of the regional stress field by volcanic intrusions.

Overall, those observations are crucial to improve our knowledge of the geodynamics in the area and to constrain boundary conditions for future numerical modeling of deformation at lithospheric scale.
Potential for virtual energy storage in a wind-PV-hydropower system in Yalong River Basin, China.
Authors: Hu Jing , Wörman Anders , Li Yu , Zhang Bingyao , Ding Wei , Zhou Huicheng
Published: March 2022

Wind and hydropower are generally more prevalent in stormy weather conditions when solar radiation is relatively lower, which is why these renewables show complimentary characteristics over time. Similarly, weather patterns show spatial covariance. This means that spatio-temporal coordination of renewable energy production can reduce significantly the variance in the system power, hence, contribute to a virtual energy storage similar as has previously been done by matching the demand response to power availability. The 130,000 km2 Yalong River Basin in southwest China is used as an example in this study and for this basin we found typical climate-controlled periods in the renewable energy variations on periods of half a year, one year and 11-years. Based on historical hydro-climatic records, results for a planned combined wind-PV-hydropower system show that the maximum virtual energy storage has similar trends under different periods, i.e. it decreases with coordination distance and stabilizes on a coordination range of between 200 – 400 km. The maximum virtual energy storage gain was found to be 737 MWh . The project developed an existing spectral method for the analysis of the variance of the potential power and virtual energy storage in combined wind-PV-hydropower systems under different climate periods. Two different scenarios were analyzed, one in which all power stations were matched regardless of transmission constraints and one in which coordination of PV and wind power is fully centralized around single hydropower stations. The virtual energy storage gain obtained at decadal long periods, such as the 11-year cycle, can also be seen as an alternative to reserve power capacity that is activated only to avoid energy droughts. This study focused on the theoretical maximum potential for virtual energy storage, but the feasibility of this potential is limited by the uncertainty associated with production optimization and the meteorologic forecasts of future energy availability.

 

 

 

 

 
Understanding heat extremes in Sub-Saharan Africa: Projected changes in UNESCO Biosphere Reserves
Authors: Maroini Amina , Giannini Alessandra , Vogel Martha-Marie
Published: March 2022

We explore the changes in climate extremes (heat stress, temperature and precipitation) as projected by the Sixth phase of the Coupled Model Intercomparison Project (CMIP6) multi-model ensemble under the ‘business as usual scenario’ (ssp585) for global warming levels from 1.0°C to 3.0°C, relative to pre-industrial levels in Sub-Saharan Africa. We focus on the 86 UNESCO-designated Biosphere Reserves located in sub-Saharan Africa, a region highly vulnerable to climate change, spanning monsoon, wet, dry and Mediterranean climate regions. Projected changes of temperature indices are significant at all warming levels across the five climate classes of Sub-Saharan Africa. Notably, absolute heat extreme indices are projected to increase more strongly than global mean temperature in monsoon  and in dry climate regions.
We found the strongest health risk to heat stress in the two monsoon and the rainy climate regions, and the lowest in the Mediterranean climate region. High risk of heat stress emerges at a global warming of 1.5°C in the northern hemisphere (NH) monsoon region, whereas only above a global warming level of 3°C in the SH monsoon and rainy climate regions. We find that limiting global mean temperature below 2.0°C reduces by a half the exposure to high levels of heat stress in the population in and around the Biosphere Reserves in Sub-Saharan Africa.
Finally, we investigated processes that might explain the differences in the regions. The NH monsoon class reaches high heat stress risks earlier, already at a global warming of 1.0°C, due to the compounding effects of temperature and humidity, as temperatures start from a warmer baseline and occur jointly with a significant increase in precipitation. While the rainy climate region also exceeds high risk thresholds, values of the different heat stress indices are highest overall in the SH monsoon region. Since the latter is a region projected to experience an intense drying, this suggests that the strong increase in heat extremes is caused by an amplification of land warming through land-atmosphere feedbacks.
Estimating Time Series of Tsunami Inundation using One-Dimensional Convolutional Neural Networks for Early Warning.
Authors: Catalan Patricio A. , Núñez Jorge , Valle Carlos , Zamora Natalia , Valderrama Alvaro
Published: March 2022

Tsunamis have the potential to cause widespread damage and loss of life over large swaths of coastal areas. To mitigate their effects, both in the long term and during emergency situations, an accurate, detailed and timely assessment of the hazard is essential. Here, an enhanced method for estimating tsunami time series using a uni-dimensional convolutional neural network model is presented, with the aim of reducing the time and computing capacity required by a high-resolution numerical modeling. While the use of deep learning for this problem is not new,  most of existing research has focused on the determination of the capability of a network to reproduce inundation values. However, for the context of Tsunami Early Warning, it is equally relevant to assess whether the networks can predict the absence of inundation. Hence, the network model was adjusted for the bays of Valparaíso, Viña del Mar and Coquimbo in central Chile, based on a set of 6800 scenarios with Mw 8.0-9.2. Tentative models were trained with time series from low- and high-resolution numerical modeling, to recreate the tsunami time series of control points on land. The objective was to reproduce the inundation high resolution time series, when the network was fed with low resolution offshore data. The approach considered 1075 (15%) scenarios to test the model, and 5783 (85%) scenarios to adjust (train and validate) the model. Different performance metrics are employed, particularly the RMSE measured with respect to peak flow depth and arrival times. Critically, the number of false alerts and alerts not issued was analyzed, which was considered a relevant performance owing to the wide range of magnitudes tested that led to an unbalance between scenarios that inundate and the ones that not. A notable outcome in this study shows the network is capable of reproducing inundation, either for small or large amplitudes, and also of no inundation. To further assess the performance, the model was tested with three existing tsunamis and compared with actual inundation metrics at three cities with different hydrodynamic response. The results obtained are promising, and the proposed model could become a reliable alternative for the calculation of tsunami intensity measures (TIMs) in a near to real time manner, with a network model forecasting where sea surface and geodetic data are not readily available, as occurs in many countries. This could complement existing early warning systems to reduce uncertainties involved in the decision making process.
Historical Structure From Motion (HSfM): An automated historical aerial photography processing pipeline revealing non-linear and heterogeneous glacier change across Western North America
Authors: Knuth Friedrich , Shean David , McNeil Chistopher , Schwat Eli , Bhushan Shashank
Published: March 2022

Mountain glaciers are responding in concert to a warming global climate over the past century. However, on interannual to decadal time scales, glaciers show temporally non-linear dynamics and spatially heterogeneous response, as a function of regional climate forcing and local geometry. Deriving long-term geodetic glacier change measurements from historical aerial photography can inform efforts to understand and project future response. 

We present interannual to decadal glacier and geomorphic change measurements at multiple sites across Western North America from the 1950s until present. Glacierized study sites differ in terms of glacial geometry and climatology, from continental mountains (e.g., Glacier National Park) to maritime stratovolcanoes (e.g., Mt. Rainier). Quantitative measurements of glacier and land surface change are obtained from Digital Elevation Models (DEMs) generated using the Historical Structure from Motion (HSfM) package. We use scanned historical images from the USGS North American Glacier Aerial Photography (NAGAP) archive and other aerial photography campaigns from the USGS EROS Aerial Photo Single Frames archive. 

The automated HSfM processing pipeline can derive high-resolution (0.5-2.0 m) DEMs and orthomosaics from scanned historical aerial photographs, without manual ground control point selection. We apply a multi-temporal bundle adjustment process using all images for a given site to refine both extrinsic and intrinsic camera model parameters, prior to generating DEMs for each acquisition date. All historical DEMs are co-registered to modern reference DEMs from airborne lidar, commercial satellite stereo or global elevation basemaps. The co-registration routine uses a multi-stage Iterative Closest Point (ICP) approach to achieve high relative alignment accuracy amongst the historical DEMs, regardless of reference DEM source. 

We examine the impact of regional climate forcing on glacier elevation change and dynamics using downscaled climate reanalysis products. By augmenting the record of quantitative glacier elevation change measurements and examining the relationship between climate forcing and heterogeneous glacier response patterns, we aim to improve our understanding of regional glacier mass change across multiple temporal scales, as well as inform management decisions impacting downstream water resources, ecosystem preservation, and geohazard risks.
An urban morphology clustering analysis to identify local heat hotspots in cities
Authors: Sützl Birgit , Strebel Dominik , Rubin Andreas , Kubilay Aytaç , Zhao Yongling , Carmeliet Jan
Published: March 2022

Heat stress in the urban environment is the result of complex interactions between the different components of the built environment and the atmosphere. Different surface materials, heterogeneity in size, shape, density and arrangement of buildings, all influence the transport and storage of heat. Due to this extensive parameter space, numerical simulations of the urban microclimate often revert to simplified parametric morphologies like urban street canyons. To be able to simulate heat mitigation measures in a more realistic set-up, this ongoing research project aims to identify typical building morphologies that are associated with higher outdoor temperatures than comparable neighbourhoods.

The study uses summer daytime surface temperatures from the Landsat 8 high-resolution satellite data, averaged over the years 2013 - 2021, to identify urban neighbourhoods with potential for high heat stress. The surface temperature data over the test city Zurich shows clear cooling effects from water bodies like rivers and lakes, medium- and large-scale vegetated areas, while extensive railway infrastructure and large outdoor sports facilities with artificial turf induce high surface temperatures. These effects are indicated by clear correlations between the surface temperature and parameters such as the impervious surface cover, vegetation cover, and sky view factor, calculated from building-resolved data at neighbourhood scale.

However, the impact of building form is less clear and requires further analysis. An ongoing investigation applies a clustering analysis with several morphological parameters (plan- and frontal area indices of buildings, mean and maximum height of buildings, etc.) to neighbourhoods with high surface temperature, that reveals typical morphology features of several distinct urban neighbourhoods. Representative building geometries can then be selected from these groups to study the adaptation of neighbourhoods to heat stress, as well as to learn lessons for densification and the design of new urban developments.
Solution-Level Fast Constraints Transformations with Case Studies for GNSS Networks
Authors: Wang Lin , Ampatzidis Dimitrios , Mouratidis Antonios , Balidakis Kyriakos
Published: March 2022

The Hermert-like constrain condition is commonly used in various space geodetic reference frame alignment and reference frame definition, this often demands discussions on the proper constrain strength, selection of fiducial network, and more. Thus, the published and constrained reference frame products/solutions are often demanded the transformation to alternative constrain condition due to the area of interest change, reduction of the coverage, or other reasons.

We present an efficient methodology to transform reference reframe product to a posterior selection of the constrained condition from the product which either minimum or redundant datum constraints have been imposed. This analytical methodology significantly reduces the computation effort for datum alignment, especially for the large GNSS network. By avoiding the expensive normal equation system reconstruction and the subsequent inversion thereof, we achieved computational complexity reduction with an inversion of an auxiliary matrix of up to 14X14 dimension, while the computation is validated analytically as well as numerically to the truncation error level. This Fast Constraints Transformation (FCT) method can be conveniently applied to the widely used space geodetic solution files following the Solution Independent Exchange (SINEX) format, especially with our provided software package written in Matlab. We validate and evaluated FCT with two globally distributed GNSS-derived solutions and one South America terrestrial reference frame. The results confirm the numerical equivalence of the classical method and FCT. We also present the discussion on the computation efficiency with the above networks as well as numerical simulations. For the large network of up to 5000 stations, The FCT accelerates the transformation by more than 100 times compared to the classical strategy.

FCT method could serve as a beneficial procedure to many TRF-related applications, including but not limited to:

Deploy Over Constain condition to an existing solution

Transforming an Over Constrained solution to a Minimal Constrained solution

Re-computation of a specified Minimal Constrained solution from an Over Constained or loosely-constrained solution.

For global networks with a large number of stations the FCT significantly reduces the computation effort.

For the cases of regional and local TRFs, the methodology shows significant advantages since the final product can be considered an Over Constrain solution.

FCT could be applied for local and regional networks removing the imposed constraints and deriving the initial GNSS network.
Systemic risk from the perspective of climate, environmental and disaster risk science and practice
Authors: Sillmann Jana , Christensen Ingrid , Hochrainer-Stigler Stefan , Huang-Lachmann Jo-Ting , Juhola Sirkku K. , Kornhuber Kai , Mahecha Miguel , Mechler Reinhard , Reichstein Markus , Ruane Alex C. , Schweizer Pia-Johanna , Williams Scott
Published: March 2022

Understanding and managing systemic risk is more important than ever due to our immense global connectivity (e.g., between sectors, such as food-health-water-energy, countries and continents, down to individuals). Despite the fact that the notion of systemic risk is several decades old, the term is used in diverse ways across different disciplines (e.g., financial systems, medicine, earth system sciences, disaster risk research and climate science). Triggered by the repercussions of the global financial crisis of the late 2000s, and more recently the COVID-19 pandemic, which are clear realization of systemic risk, the perception of systemic risk has often been focused on global and catastrophic or even existential risks.  Systemic risk, however, can be seen as a feature of systems at all possible scales (e.g., global, national, regional, local) with system boundaries varying depending on the context.

Addressing current societal challenges, such as climate change, in terms of systemic risk requires integrating different systems perspectives and fostering system thinking, while implementing key intergovernmental agendas, such as the Paris Agreement, the Sendai Framework for Disaster Risk Reduction and the Sustainable Development Goals.

Based on insights gained and knowledge collected from an expert workshop, literature review and expert elicitation, we give an integrated perspective of climate, environmental and disaster risk science and practice on systemic risk as summarized in a Briefing Note to the International Science Council. We provide an overview of concepts of systemic risk that have evolved over time and identify commonalities across terminologies and perspectives associated with systemic risk used in different contexts. Key attributes of systemic risk are outlined without prescribing a single definition, and information and data requirements are discussed that are essential for a better and more actionable understanding of the systemic nature of risk. Finally, the opportunities to connect research and policy for addressing systemic risk are highlighted.
Insights into magma degassing processes during the 2021 Cumbre Vieja eruption, La Palma, from open-path FTIR spectroscopy
Authors: Pardo Cofrades Ana , Burton Mike , Asensio-Ramos María , Barrancos José , La Spina Alessandro , Allard Patrick , Hayer Catherine , Esse Benjamin , Hernández Pedro A. , Padrón Eleazar , Melian Gladys V. , Peréz Nemesio  M.
Published: March 2022

On September 19th 2021 a fissure eruption started on the Cumbre Vieja rift on La Palma, Canary Islands. The fissure eruption rapidly evolved into a cone-forming eruption, with several summit vents producing explosive activity and lava jetting, while lava spattering and effusive activity occurred at/from lower flank vents.

We used open-path Fourier transform infrared spectroscopy (OP-FTIR) to measure the chemical composition of degassing associated with both explosive and effusive activities, using absorption spectra of the radiation emitted by molten lava and incandescent ash. Measurements were performed daily since October 2nd until the end of the eruption (mid-December), from different sites and at distance range of 0.6 to 5 km from the vents. They allowed us to retrieve the molar proportions of H2O, CO2, SO2, HCl and CO in gas emissions from the different vents and different activities.

In this work, we report the main results obtained for the gas compositions, their spatial and temporal evolution during the eruption, the influence of fragmentation (ash) on the degassing of HCl, and the gas-magma redox state during the La Palma 2021 eruption.
Measurement of viscosity at low temperature from resonating droplet levitated in an electrodynamic balance
Authors: Singh Mohit , Jones Stephanie , Duft Denis , Kiselev Alexei , Leisner Thomas
Published: March 2022

Recent observations in the field measurements and laboratory studies suggest that organic aerosol particles may exist as highly viscous semi-solids or amorphous glassy solids under certain conditions, with important implications for atmospheric chemistry, climate, and air quality. A number of complementary techniques have been developed to probe the viscosity of aerosol particles in the last ten years. However, none of the available techniques is sufficiently versatile to determine aerosol viscosity at atmospherically relevant conditions for a range of particle sizes, chemical compositions, and sample sizes. Here we present a novel way to measure the viscosity of levitated droplets suspended in an electrodynamic balance under atmospheric conditions. Capillary oscillations are induced in a levitated droplet by the application of an external AC field. These oscillations are monitored using a high-speed camera or light scattering, and the viscosity is determined by fitting these oscillations using a suitable theoretical model. The model is based on the asymptotic analysis of surface oscillations of a charged drop, carried out using the viscous-potential flow theory.
Using CMIP6 simulations to assess significance of an AMOC trend seen by the RAPID array
Authors: Straub David , Kelson Richard , Dufour Carolina
Published: March 2022

Observations between 2004 and 2020 at the RAPID array suggest a weakening trend in the Atlantic Meridional Overturning Circulation (AMOC). To assess the significance of this trend, trends that one might expect from natural variabilty in a time series of this length are assessed using CMIP6 pre-industrial simulations. The observed trend is not found to be statistically significant relative to this benchmark. Both the observed trend and the standard 
deviation of short-term model trends are found to decrease in magnitude with time. The rate of decrease, however, is faster for the observed trend, further calling into question its significance.

To clarify how variability in short-term model trends is related to power spectra of modelled AMOC strength, a conceptual model is developed. Essentially, trend variance is represented by a random walk in which there is one step for each frequency bin of the power spectrum (with step size determined by the frequency and variance of the bin in question). Most models are found underestimate interannual variability in AMOC strength; however, it is the variability at somewhat longer time scales that most influences model trends. This variability is represented quite differently between the various CMIP6 models. The conceptual model is also used to illustrate how the detectability threshold for trend detection (i.e., the 2 sigma level in a PDF of short-term model trends) is altered by the addition of noise added to make AMOC variance more in line with observations. 

 
Dilution of boundary layer cloud condensation nucleus concentrations by free tropospheric entrainment during marine cold air outbreaks
Authors: Tornow Florian , Ackerman Andrew , Fridlind Ann , Cairns Brian , Crosbie Ewan , Kirschler Simon , Moore Richard , Robinson Claire , Seethala Chellappan , Shook Michael , Voigt Christiane , Winstead Edward , Ziemba Luke , Zuidema Paquita , Sorooshian Armin
Published: March 2022

Mid-latitude marine cold air outbreaks (CAOs) occur in the post-frontal sector of extratropical cyclones. Once advected over the ocean, the marine boundary layer (MBL) quickly deepens and hosts near-overcast clouds that transition into an open-cellular cloud field downwind, mediated by a reduction in aerosol concentrations. Typically, the MBL experiences strong large-scale subsidence that is often associated with free-tropospheric (FT) dry intrusions. Apart from being relatively warm and dry, FT air may have substantially different aerosol properties and, thus, different cloud condensation nuclei (CCN) concentrations compared to the MBL.

In this study, we examine the difference between MBL and FT air by using in-situ and remote sensing observations collected during NASA's ACTIVATE (Aerosol Cloud Meteorology Interactions over the Western Atlantic Experiment) field campaign in the northwest Atlantic. Analysis of the 8 CAO flights in 2020 reveals predominantly far lesser CCN concentrations in the FT than in the MBL. We investigate one representative flight more deeply, through a fetch-dependent MBL CCN budget that has contributions from sea-surface fluxes, hydrometeor collision-coalescence, and entrainment of FT air. We find a dominant role of FT entrainment in reducing MBL CCN concentrations upwind of strong precipitation that results in cloud regime transition, consistent with satellite-retrieved gradients in droplet number concentration upwind of precipitation.

The FT circulation and its relative lack of CCN can accelerate overcast-to-broken cloud transitions, especially where MBL air is CCN-rich (e.g., near continents), and thereby dramatically reduce regional albedo.

 
Design and Testing of a MEMS Semi-Absolute Pendulum Gravimeter 
Authors: Utting Phoebe , Walker Richard , Prasad Abhinav , Hammond Giles , Middlemiss Richard
Published: March 2022

Gravimetry has many useful applications from volcanology to oil exploration; being a method able to infer density variations beneath the ground. Therefore, it can be used to provide insight into subsurface processes such as those related to the hydrothermal and magmatic systems of volcanoes. Existing gravimeters are costly and heavy, but this is changing with the utilisation of a technology most notably used in mobile phone accelerometers: MEMS – (Microelectromechanical-systems). A team at the University of Glasgow has already developed a MEMS relative gravimeter and is currently collaborating with multiple European institutions to make a gravity sensor network around Mt Etna - NEWTON-g. A second generation of the MEMS sensor is now being designed and fabricated in the form of a semi-absolute pendulum gravimeter. Gravity data for geodetic and geophysical use were provided by pendulum measurements from the 18th to the 20th century. However, scientists and engineers reached the limit of fabrication tolerances and readout accuracy approximately 100 years ago. With nanofabrication and modern electronics techniques, it is now possible to create a competitive pendulum gravimeter again. In this presentation the design and fabrication techniques of a new MEMS pendulum gravimeter will be outlined. The design comprises two pendula, which oscillate in anti-phase to reduce the influence of seismic noise. Nanofabrication methods have been used to create both flexure and knife-edge pivot points. An optical shadow-sensor has been developed to monitor the position of the pendula. This optical readout can provide measurements to sub-nanometre precision. Data collected from laboratory testing will be presented, demonstrating the progression being made towards a prototype field device. This data will include measurements of the influence of tilt-sensitivity and the seismic and shadow sensor noise floors.  Altitude tests of the free-air effect will be presented to demonstrate the current sensitivity of the device. If semi-absolute values of gravity can be measured, then instrumental drift concerns are reduced. Additionally, the need for calibration against commercial absolute gravimeters may not be necessary. This promotes improved accessibility of gravity measurements at an affordable cost.
Lithosphere response to erosion: Model and case studies
Authors: Medvedev Sergei , Hartz Ebbe
Published: March 2022

Extensive surface erosion may cause sizable lithospheric deformations. The effects are even more remarkable in regions subjected to glacial erosion. The isostatic response shielded by flexurally strong lithosphere is usually wider than localized glacial erosion and causes non-linear local effects. We use erosion backward in time (EBT) to model this process. In our experiments, we numerically fill the eroded voids with crustal material and calculate isostatic response to this added surface load. We assume that these calculations approximate amplitudes of erosion-related processes occurred in nature. Our studies started with considering enigmatic marine Mesozoic sediments stored at the elevation of 1.2 km in central east Greenland, the area free from recent compressional tectonic processes. The location is surrounded by the world’s biggest fjord system, Scoresby Sund. Application of the EBT allows us to estimate the unloading by the glacial fjord carving and conclude about a km-scale regional uplift explaining elevated marine sediments. Similar study on the development of the Europe’s biggest plateau, Hardangervidda in the southern Norway, demonstrated that glacial erosion caused up to 40% uplift of the plateau. Analyzing the Quaternary evolution of the North Sea, we found that on-shore erosion and off-shore sediment accumulation results in differential vertical motion of the lithosphere of up to 1 km across the sea. Applied to a particular petroleum system, the Troll field, this tilting explains significant oil spilling during the Quaternary.
Bias adjustment of RCM simulations in high-latitude catchments: complexity versus skill in a changing climate
Authors: Teutschbein Claudia , Tootoonchi Faranak , Todorovic Andrijana , Räty Olle , Haerter Jan , Grabs Thomas
Published: March 2022

For climate-change impact studies at the catchment scale, meteorological variables are typically extracted from ensemble simulations provided by global (GCMs) and regional climate models (RCMs), which are then downscaled and bias-adjusted for each study site. For bias adjustment, different statistical methods that re-scale climate model outputs have been suggested in the scientific literature. They range from simple univariate methods that adjust each meteorological variable individually to more complex and statistically as well as computationally more demanding multivariate methods that take existing relationships between meteorological variables into consideration. While several attempts have been made over the past decade to evaluate such methods in various regions, there is no guidance for choosing an appropriate bias adjustment method in relation to the study question at hand. In particular, the question whether more complex multivariate methods are worth the effort by resulting in better adjustments of a wide range of univariate, multivariate and temporal features, remains unanswered. 
We here present an approach to systematically assess the performance of the most commonly used univariate and multivariate bias adjustment methods at different catchment scales in Sweden. Based on a multi-catchment and multi-model approach, we evaluated numerous univariate, multivariate and temporal features of precipitation, temperature and streamflow. Finally, we discuss potential benefits (skills and added value) and trade-offs (complexity and computational demand) of each method, in particular for hydrological climate-change impact studies in high latitudes.
Calibrating an ensemble of 1,000 realizations for estimating the uncertainty of aquifer properties in the vicinity of a long‐lived radioactive waste repository using a script-driven approach (on a Friday afternoon)
Authors: Kushnereit Ross
Published: March 2022

Groundwater models are simplified and simulated depictions of aquifer systems that represent flow and/or transport of groundwater. For decades, practitioners would construct a model with the help of a graphical user interface (GUI) for a simulator such as MODFLOW, a finite-difference groundwater flow modeling program written by the United States Geological Survey (USGS). Due to the nature of GUIs, most of the time (and therefore cost) went in to the creation of model input datasets, and the “calibration” of the model would be hastily rushed at the end of the project time window. Unfortunately, the calibration process will almost certainly reveal issues derived from early stages of the project, and in the GUI framework it can take significant time and effort to manually address issues with the upstream workflow elements.

More recently, script-driven modeling workflow tools have been made available for practitioners to use to mitigate the time and cost associated with undertaking complex groundwater modeling analyses. Tools like FloPy and pyEMU python packages for interfacing with MODFLOW and the parameter estimation software PEST and PEST++.  When used together, these tools allow for all workflow steps to be automated, including the creation of the model input datasets as well as deployment analyses like data assimilation and uncertainty analysis.  More importantly, a script-driven approach allows issues (which statistically will always occur) to be addressed cleanly and efficiently, with minimal effort and little to no loss of practitioner time.

In this presentation, we present the development and implementation of a decision-support workflow for the history matching of 1,000 geostatistical realizations of transmissivity, storage, anisotropy, and recharge using multiple simulations. This work is part of a larger risk-analysis for the Waste Isolation Pilot Plant (WIPP) project in southeastern New Mexico. The predictive focus is on estimating particle travel times of long-lived radionuclides. 

Using script-driven approaches and recent iterative ensemble smoother techniques, our team was able undertake an advanced data assimilation analysis in a few hours one afternoon using a single workstation.  Previously, a similar analysis for the WIPP project took months of practitioner time on a massively parallel super-computer.
Temperature effect on the residual shear strength.
Authors: García Luis M. , Soncco Edwin A. , Pinyol Núria M. , Lloret Antonio
Published: March 2022

The available strength on slip surfaces in landslide after a significant displacement and at motion is the residual strength. The residual strength depends on the soil properties including both solid skeleton (mineralogy, particle shape and size, index properties) and pore fluid (chemical and rheological properties). The available strength also depends, as extensively reported in the literature, on several factors that may not remain constant in time and affect the landslide stability and dynamics: applied stress, accumulated displacement and shear strain rate. With a less extensive literature related to, the effect of temperature on the residual strength have been also observed.

This work reports on the results of a large number of ring shear tests under controlled rate and temperature performed on different types of soils. The results are interpreted in terms of the influence of mineralogy, clay content and plasticity on temperature effects on residual strength.
Hillslope to stream coupling revealed by time-lapse georadar: case study of Capetinga watershed in Brazilian Savanna
Authors: Uagoda Rogerio , Hussain Yawar , Almeida Andréia , Maciel Susanne , Zakarewicz de Aguiar Guilherme , Qiangshan Gao , Borges Welitom , Koide Sergio , Nguyen Frederic , Carvalho do Nascimento Carlos Tadeu
Published: March 2022

The hillslope-stream connectivity, an important contributor to streamflow generation and surface water quality, depends both on the surface networks and the subsurface structure. The connectivity is dynamic and affected by certain processes (meteorological events) and local site conditions and it may have coupled or decoupled accordingly. Compared to factors affecting the surface networks such as vegetation or slope, subsurface connectivity is challenging to assess because of the limited availability of direct observations. In this context, the present study explored the potential of time-lapse ground-penetrating radar to quantify this connectivity together with in situ soil moisture measurements at a small hillslope in Capetinga stream, Brasilia, Brazil. The study period covers the dry and wetting periods from August 2015 to February 2016.

Geophysical surveys were conducted using 200 MHz and 400 MHz antennas with the approximate depths of investigation 4m and 9m respectively, covering an area of approximately 200 m2 in the considered watershed. Data were acquired along five parallel profiles and one orthogonal profile to the Capetinga stream. At different locations on these profiles, the soil moisture was estimated at different depths using gravimetric and time-domain reflectometry probes to compare both direct and indirect data. This configuration allowed the characterization of the subsurface as well as the change in degree of moisture in different seasons.

A multi-attribute analysis, including coherence, energy and amplitude of the signals was applied to the dataset at considered time scales to highlight the discontinuities of the subsurface in terms of structures and water content. Additionally, a Hilbert transform analysis provided an extra layer to achieve the study objectives.

The present study demonstrates that time-lapse GPR surveys together with in situ data offer a practical and nondestructive way of understanding complex subsurface flow processes across the landscape that lead to hillslope-stream connectivity in the field. This study is an initial step to understand the cerrado environment that is a unit of essential landscape at the watershed scale.

Keywords: Attribute analysis;  non-invasive; Hilbert transportation; time-domain reflectometry

 
Aerosol property retrievals with the use of an airborne compact multi-angle polarimeter (C-MAP)
Authors: Gialitaki Anna , Dhillon Ranvir , Panagi Marios , Lodge Alexander , Lloyd Steven , Di Noia Antonio , Boesch Hartmut , Tsekeri Alexandra , Vande Hey Joshua
Published: March 2022

Atmospheric aerosol particles originating either from natural (i.e. dust, volcanic ash, smoke, sea salt) or anthropogenic (i.e. pollution, agricultural activities) sources, affect the Earth’s climate through absorption and scattering of the incoming solar radiation and cloud property modifications. Aerosols can further significantly deteriorate air quality and result in adverse human health problems.

Aerosols multifarious effects depend on their intrinsic optical properties and their load, as well as the radiative characteristics of the underlying surface. The quantification of the aerosol net effect on the Earth’s radiative budget is subject to large uncertainties owing to the rapid temporal and spatial changes of the aerosol field and the aerosol properties. Multi-angular polarimetric remote sensing can provide detailed information on aerosol microphysical and optical properties in order to better constrain the aerosol radiative forcing and chemical composition.

The Compact Multi-Angle Polarimeter (C-MAP) is an airborne sensor that will provide highly accurate measurements of intensity and polarization at 7 measurement wavelengths (410, 443, 490, 555, 670, 753 and 865nm) and 5 different viewing angles (0, ±15 and ±40°). C-MAP is currently being developed by Thales Alenia Space-UK in collaboration with the University of Leicester. The project aims to incorporate the MAP technology into a compact airborne MAP that will fly on board a UK demonstrator flight in late 2022. The instrument design is based on the upcoming MAP sensor on-board the CO2M mission (Sierk et al., 2021; Spilling et al., 2021), also developed by TAS-UK.

Herein we illustrate the performance of C-MAP in terms of aerosol and surface property retrievals using the Generalized Retrieval of Atmosphere and Surface Properties (GRASP) algorithm (Dubovik et al., 2011; 2021). Our analysis is carried out using simulated radiances generated by GRASP for various synthetic scenes characterized by pre-assumed atmospheric conditions in terms of aerosol content (shape, size, composition and load), solar zenith angle and surface albedo.  The series of sensitivity tests developed, aims to verify the C-MAP capability to derive a set of aerosol optical and microphysical properties along with surface characteristics. Here, microphysical properties include the aerosol size distribution, complex refractive index and fraction of spheres for coarse mode, while optical properties consist of the aerosol optical depth (AOD) and single scattering albedo (SSA). Surface reflectance is described through retrievals of Bidirectional reflectance distribution function (BRDF) and Bidirectional Polarization Distribution Function (BPDF) parameters.
Combination of geodetic techniques for deformation monitoring during 2021 La Palma eruption  
Authors: González-Alonso Elena , Lamolda Héctor , Quirós Francisco , Molina Antonio Jesús , Fernández-García Anselmo , García-Cañada Laura , Pereda de Pablo Jorge , Domínguez-Valbuena Jorge , Prieto-Llanos Fernando , Sáez-Gabarrón Lucía
Published: March 2022

Surface deformation is considered one of the most important parameters in volcano monitoring. That was shown during the recent Cumbre Vieja eruption (La Palma, Canary Islands) which started on 19th September 2021 and lasted almost three months. Several days after the beginning of the unrest, on 11th September, deformation data were able to confirm the depth of the volcanic intrusion and constrain an approximate volume.Maximum deformation of 20 cm were measured prior to the beginning of the eruption pointing to the area were the dike finally reached the surface. 

After the eruption onset, deformation monitoring resulted essential to understand eruption dynamics. This work is focused on results obtained by the geodetic techniques operated by Instituto Geográfico Nacional (IGN) during the three months of volcanic activity.  This system includes GNSS permanent stations, InSAR processing, tiltmeters and a GNSS-RTK periodic measurements on benchmarks around Cumbre Vieja. It allowed to measure displacements with different temporal and spatial scales providing a complete picture of the deformation, which, together with other geophysical parameters, helped to manage the volcanic crisis and interpret the magmatic processes.