bluuebunny/crossref_metadata_2025 huggingface dataset:
Perturbing the flow duration curve to explore future flow conditions without a hydrological model
Authors: Rougé Charles , Yildiz Veysel , Brown Solomon
Published: March 2022

Assessing the robustness of a water resource system to climate change involves exploring a range of streamflow conditions. For this, rainfall-runoff models are routinely to produce future streamflow, using as inputs either climate model projections or modified historical hydro-climatic conditions. However, these models have generally been calibrated and validated under historical conditions, and there is no guarantee that calibrated parameters would still be valid in a different climate. Indeed, recent literature suggests that rainfall-runoff models’ predictive skill decreases with changed climatic conditions especially when predicting drier climates. What is more, rainfall-runoff models require time, expertise and input data to calibrate and validate against the historical streamflow record.

With this abstract, we propose an alternative approach based on a near-universal parameterisation of flow duration curves (FDCs), and perturbation of these parameters to simulate a range of futures. Our method represents FDCs with a three-parameter function called the Kosugi model, which has been shown to provide an excellent approximation to FDCs under a wide range of climates. We directly relate these three parameters with three streamflow statistics that are of interest to water resource management: median, coefficient of variation, and first percentile. These values represent central tendency, variability, and low flow characteristics respectively. As a result, a broad range of changes in streamflow can be related to modified parameters, and our method goes through the following steps: (1) Kosugi model parameters are calibrated with a historical FDC, (2) a set of scenarios with modified flow statistics are determined, (3) a new set of coefficients of the Kosugi model are derived for each future scenario, (4) future scenarios are created by using these coefficients.

We apply this method to represent possible climate change impacts on the hydrology of seven headwater basins from different geographical and climatic conditions in Turkey. Preliminary results show that this method provides a dramatically large range of inflows, with increased frequency of high flows and low flows to better represent hydrological variability and extremes. This then supports robustness analyses for rivers for which no detailed hydrological model is available: here, on the financial viability of run-of-river hydropower design in a changing climate. The method supports time series with a large number of no-flow days.
Simulating Convective GWs forced by Radar-Based, Neural-Network-Predicted Diabatic Heating
Authors: Kruse Christopher , Alexander M. Joan , Bramberger Martina , Hassanzadeh Padram , Chattopadhyay Ashesh , Green Brian , Grimsdell Alison
Published: March 2022

Convection, both observed and modeled, generates gravity waves (GWs) that significantly impact large-scale circulations in the stratosphere and above. However, models that permit convection and resolve the GWs they generate cannot reproduce the timing, location, and intensity of the actual convective cells that generate the observed convective GWs. This issue prevents comparison of observed and modeled convective GWs and model validation/evaluation. 

Here, convective latent heating is predicted based on radar observations and provided to an idealized version of WRF, allowing WRF’s dynamics to generate convective updrafts/downdrafts and generated convective GWs both mechanically and diabatically. Two methods are used to predict convective latent heating: the composited lookup table of Bramberger et al. 2020 and neural networks (NNs) using the same, and additional, input variables. Offline performance of the NN-predicted latent heating can be improved over the previous method when more input variables are used. Preliminary comparisons of modeled and observed (via superpressure-balloon and satellite) convective GWs will be presented. 
Formalization of experimental setups for integration of heterogeneous data
Authors: Vladimirov Artem , Vasiliev Taras , Pashkov Alexander , Vasilyeva Nadezda
Published: March 2022

The undoubted challenge for science is the extraction of knowledge from fast growing heterogeneous datasets. Particularly, details of experimental setups are insufficiently formalized and can not be easily inserted into databases to be taken into account in the process of data integration and meta analyses.

For this purpose, we developed a scheme of formalization for object descriptions with its origination, protocols for field and laboratory measurements (including instruments and experimental conditions). It allows the integration of larger amounts of data accounting for its specifics of acquisition, for example, by applying adjustments, assigning weights to data sources (based on its reliability, method precision and experimental uncertainty) or directly accounting for experimental conditions in models.

This formalization is currently used to develop an electronic laboratory journal for soil research, intended for detailed description of a conducted or planned experiment.

The study aims to: 1) increase the reproducibility of scientific research results, 2) allow automatic data processing and error detection, and most importantly, 3) effective soil data mining for decision support systems.
Phanerozoic scale modulation of brachiopod longitudinal expansion fitness forced by plate tectonics
Authors: Spiridonov Andrej , Balaukauskas Lauras , Lovejoy Shaun
Published: March 2022

Brachiopods are a phylum of Animalia which are characterized by a rich fossil record. But this record shows drastic decrease in brachiopod diversity and environmental occupancy through time. One set of explanations says that the decline is related to the state shifts in dominance after mass extinction events (usually P-Tr). Another explanatory set suggests that the dominant cause of brachiopod decline is competition with other functionally similar clades. The competition hypothesis predicts that there should be a monotonic decrease in some fitness metric at organismal or species level. Often overlooked is the influence of long-term tectonic processes which control size, geometry and topology of environments on the changes in dominance of brachiopods. Here we tested this hypothesis by analyzing the dynamics of longitudinal and latitudinal ranges of brachiopod genera in the post-Cambrian Phanerozoic using the Paleobiology Database global paleogeographic occurrence data. The major pattern revealed in the study is that while latitudinal ranges were approximately constant through the eon, the longitudinal ranges experienced long-term trend-like decline. In the beginning of the Phanerozoic and also during the Cretaceous-Cenozoic, average ranges of brachiopod genera were much more elliptic in the west-east direction, while in the middle of the Phanerozoic they become almost circular in their shape. The latitudinal ranges reflect average temperature tolerance of a genus, while the longitudinal ranges reflect capacity of a genus to expand in similar climatic conditions, thus reflecting its potential of expansion fitness. The scale by scale analysis of range shapes and continental fragmentation index found consistent scale independent positive correlation of ellipticity (in W-E direction) with higher fragmentation of continents. Therefore the analyses revealed statistically significant patterns that support the hypothesis of a strong tectonic control on the shapes and sizes of average geographic ranges of brachiopod genera. Smallest ranges with lowest ellipticity occurred in Triassic-Jurassic. Therefore, the loss of genus level expansion fitness due to tectonic amalgamation of Pangaea should have been an important factor which contributed to the failure of brachiopods to fully recover after P-Tr extinction event.

This study was supported by the project S-MIP-21-9 “The role of spatial structuring in major transitions in macroevolution”.
New granular rock-analogue materials for simulation of multi-scale fault and fracture processes
Authors: Massaro Luigi , Adam Jürgen , Jonade Elham , Yamada Yasuhiro
Published: March 2022

Dynamically scaled experiments allow the direct comparison of geometrical, kinematical and mechanical processes between model and nature. The geometrical scaling factor defines the model resolution, which depends mainly on the density and cohesive strength ratios of model material and natural rocks. Granular materials such as quartz sands are ideal for the simulation of upper crustal deformation processes as a result of similar nonlinear deformation behaviour of granular flow and brittle rock deformation. We compared the geometrical scaling factor of common analogue materials applied in tectonic models and identified a gap in model resolution corresponding to the outcrop and structural scale (1–100 m).

In this study, we present a new granular rock-analogue material (GRAM) with a dynamic scaling suitable for the simulation of fault and fracture processes in analogue experiments. The proposed material is composed of silica sand and hemihydrate powder and is suitable to form cohesive aggregates capable of deforming by tensile and shear failure under variable stress conditions. Based on dynamical shear tests, GRAM is characterized by a similar stress-strain curve as dry silica sand, has a cohesive strength of 7.88 kPa and an average density of 1.36 g cm−3. The derived geometrical scaling factor is 1 cm in model = 10.65 m in nature. For a large-scale test, GRAM material was applied in strike-slip analogue experiments. Early results demonstrate the potential of GRAM to simulate fault and fracture processes, and their interaction in fault zones and damage zones during different stages of fault evolution in dynamically scaled analogue experiments.
How land cover changes affect ecosystem productivity
Authors: Krause Andreas , Papastefanou Phillip , Gregor Konstantin , Layritz Lucia , Zang Christian S. , Buras Allan , Li Xing , Xiao Jingfeng , Rammig Anja
Published: March 2022

Historically, many forests worldwide were cut down and replaced by agriculture. While this substantially reduced terrestrial carbon storage, the impacts of land-use change on ecosystem productivity have not been adequately resolved yet.

Here, we apply the machine learning algorithm Random Forests to predict the potential gross primary productivity (GPP) of forests, grasslands, and croplands around the globe using high-resolution datasets of satellite-derived GPP, land cover, and 20 environmental predictor variables.

With a mean potential GPP of around 2.0 kg C m-2 yr-1 forests are the most productive land cover on two thirds of the global suitable area, while grasslands and croplands are on average 23 and 9% less productive, respectively. These findings are robust against alternative input datasets and algorithms, even though results are somewhat sensitive to the underlying land cover map.

Combining our potential GPP maps with a land-use reconstruction from the Land-Use Harmonization project (LUH2) we estimate that historical agricultural expansion reduced global GPP by around 6.3 Gt C yr-1 (4.4%). This reduction in GPP induced by land cover changes is amplified in some future scenarios as a result of ongoing deforestation but partly reversed in other scenarios due to agricultural abandonment.

Finally, we compare our potential GPP maps to simulations from eight CMIP6 Earth System Models with an explicit representation of land management. While the mean GPP values of the ESM ensemble show reasonable agreement with our estimates, individual Earth System Models simulate large deviations both in terms of mean GPP values of different land cover types as well as in their spatial variations. Reducing these model biases would lead to more reliable simulations concerning the potential of land-based mitigation policies.
The Moon Science Working Group of the Lunar Gravitational-Wave Antenna Project
Authors: Frigeri Alessandro , Olivieri Marco , Harms Jan , Bonforte Alessandro , Giunchi Carlo , Komatsu Goro , Majstorović Josipa , Massironi Matteo , Melini Daniele
Published: March 2022

Lunar Gravitational-wave Antenna (LGWA) proposes to deploy an array of high-end seismometers on the surface of the Moon. The LGWA network will measure the lunar surface displacement excited by Gravitational waves (GWs) with a targeted observation band of 1mHz – few Hz.   Seismic noise in that frequency band is very low due to the absence of atmosphere and oceans, representing the main inherent advantage that makes the Moon an ideal target for a GW detection experiment. 

The scientific and technical challenges of LGWA are diverse.  Since its initiation, LGWA has relied on experts from fundamental physics, astrophysics, geophysics, engineering, and planetary science. 

The collaboration is currently organized in working groups (WGs) to cover five key themes: GW science, lunar science, payload, deployment, and operations.  

At the beginning of 2022, we started the activities of WG2 to assess the current knowledge of the lunar environment. We aim to characterize and develop models of deployment scenarios suitable for LGWA sensors, via a multi-pronged approach of data analysis and on-field experiments probing terrestrial analogs of lunar terrains. 

Besides characterizing the lunar seismic background noise, other goals of the group are related to modeling the lunar interior structure as well as Moon’s normal modes. These will be further used to develop a model of the interaction between the Moon and GWs. The knowledge about the displacement level of this excitation and the background noise will be used to define novel techniques for background noise reduction.

For this purpose, WG2 is composed of physicists, engineers, geophysicists, and geologists. For our activities, we chose an interdisciplinary approach that requires initial communication efforts to create a common ground that will evolve into a crucial baseline activity for the whole LGWA project.

Here we will report our progress in the first months of the activity of our collaboration.     
Holocene history of Rio Tranquilo Glacier, Monte San Lorenzo (47°S), Central Patagonia
Authors: Sagredo Esteban , Reynhout Scott , Kaplan Michael , Aravena Juan , Araya Paola , Luckman Brian , Schwartz Roseanne , Schaefer Joerg
Published: March 2022

A well-resolved glacial chronology is crucial to compare sequences of glacial/climate events within and between regions, and thus, to unravel mechanisms underlying past climate changes. Important efforts have been made towards understanding the Holocene climate evolution of the Southern Andes; however, the timing, patterns and causes of glacial fluctuations during this period remain elusive. Advances in surface exposure dating techniques, together with the establishment of a Patagonian 10Be production rate, have opened new possibilities for establishing high-resolution glacial chronologies at centennial/decadal scale. Here we present a new comprehensive Holocene moraine chronology from Mt. San Lorenzo (47°S) in central Patagonia, Southern Hemisphere. Twenty-four new 10Be ages, together with three published ages, indicate that the Río Tranquilo glacier approached its Holocene maximum position sometime, or possibly on multiple occasions, between 9860 ± 180 and 6730 ± 130 yr. This event(s) was followed by a sequence of slightly smaller advances at 5750 ± 220, 4290 ± 100 (?), 3490 ± 140, 1440 ± 60, between 670 ± 20 and 430 ± 20, and at 390 ± 10 yr ago. By comparing our results with other glacier chronologies from central and southern Patagonia, we explore the role of the Southern Westerly Winds as a pacemaker of the Holocene glacier fluctuation in southern South America. 
Geodynamic constraints on ophiolite emplacement
Authors: Ibragimov Iskander , Moulas Evangelos
Published: March 2022

Ophiolite complexes are commonly found outcropping along ancient suture zones in continental regions. Many geological studies suggest that, during subduction initiation, a small remnant of the oceanic crust can be thrusted upon continenal regions. This thrusting occurs during a process that is generally termed as “ophiolite obduction”. Despite the relatively small volume of the ophiolite rocks, their occurence provides important geologic/geodynamic constraints for the processes of subduction initiation. 
Following the seminal work of Cloos (1993), oceanic lithosphere that is older than 10 Myrs is dense enough, and as a result, facilitates oceanic subduction in a spontaneous manner. This suggestion is based on the fact that buoyancy is one of the most important forces relevant to large-scale geodynamics. However, old oceanic lithosphere is also expected to be cold and, as a consequence, mechanically strong. The increased strength of the oceanic lithosphere hinders subduction initiation and makes ophiolite obduction difficult.
In this work we perform systematic numerical simulations to investigate the effects of initial geometry and convergence velocity on subduction initiation and ophiolite obduction. We use LaMEM to calculate 2D thermo-mechanical models that include the effects of visco-elasto-plastic rheology. In addition, we have incorporated a thermodynamically-consistent density structure for the crust and mantle. In this way, buoyancy forces are calculated in a consistent manner based on the pressure and temperature fields of the thermo-mechanical models. Our results show that when the oceanic lithosphere is older than 10Myr, subduction is very difficult and does not initiate in a spontaneous manner. Our systematic simulations provide insights for the range of conditions and parameters of oceanic subduction and ophiolite emplacement.

References
Cloos, M. (1993) Lithospheric Buoyancy and Collisional Orogenesis: Subduction of Oceanic Plateaus, Continental Margins, Island Arcs, Spreading Ridges, and Seamounts. Geological Society of America Bulletin, 105, 715-737.
https://doi.org/10.1130/0016-7606(1993)105<0715:LBACOS>2.3.CO;2
Correlation of magnetic pore fabrics with traditional pore fabric characterization and permeability anisotropy in typical sedimentary rocks and hot isostatically pressed samples
Authors: Zhou Yi , Pugnetti Michele , Foubert Anneleen , Lanari Pierre , Neururer Christoph , Biedermann Andrea
Published: March 2022

Pore-scale experiments are crucial to obtain pore geometry and distribution, i.e., pore fabrics, controlling preferred fluid flow directions in rocks. Pore fabrics are characterized to derive models, which are important for hydrocarbon exploration and geothermal applications. X-ray computed tomography (XRCT) is one typical method to obtain three-dimensional pore fabrics, but limited by its micron-scale resolution in 1-inch cores. Magnetic pore fabrics (MPFs) were proposed as a fast and efficient way to indirectly measure the pore fabrics, and target micropores down to 10 nm. Empirical relationships exist between MPFs and pore space properties, and between MPFs and permeability anisotropy. Previous studies investigated a limited number of rock types or plastic synthetic samples with simplified pores to compare MPFs, pore fabrics and permeability anisotropy. Permeability is commonly estimated from measurements parallel and perpendicular to the macroscopic fabric, and thus the measurement needs a priori information on the fabric orientation. This study integrates complementary measurements to characterize pore fabrics on various scales: pycnometer porosity, MPF, XRCT, and permeability anisotropy measurements. The specimens include various kinds of sandstones and carbonates to cover the main sedimentary lithologies, and hot isostatically pressed (HIP) samples of simple and controlled compositions to bridge the gap between the synthetic samples of previous studies and complex natural rocks. HIP samples were made by mixing calcite and muscovite powders in different proportions and grain sizes, and were cold pressed at 20 MPa and then hot pressed at 160 MPa and 670 °C. Full permeability tensors including confidence angles were determined, and each tensor was calculated from 7 directional permeability measurements for natural rocks. Considering the uniaxial symmetry of the HIP samples, 3 directional measurements are sufficient to calculate a tensor with confidence angles. One additional core from each block was scanned by XRCT with ~5.5 µm pixel size for 3D pore fabric analysis, prior to being impregnated with ferrofluid to measure MPFs. A total shape ellipsoid, representing the average XRCT-derived pore fabric, is compared with other second-order tensors, permeability anisotropy and MPFs. Initial data suggest that the maximum principal directions of permeability anisotropy, total shape ellipsoids and MPFs are coaxial in homogeneous samples with consistent pore space anisotropy. These confirmed quantitative correlations help to apply MPFs as an efficient method to determine pore fabrics and predict preferred flow direction.
Influence of a yield stress on lower mantle dynamics: filtering and changing morphology of plumes and slabs
Authors: Davaille Anne , Chasse Thibaut , Ribe Neil , Carrez Philippe , Cordier Patrick
Published: March 2022

When a fluid can experience a "jammed" state, it will flow only when the local deviatoric stress becomes greater than a critical stress, the so-called  "yield-stress". Jamming can be caused by entangled dislocations in a mineral, or by the existence of a hard skeleton in a two-phase fluid. According to recent numerical modeling, a Bridgmanite lower mantle would predominantly deform by pure dislocation climb; and due to dislocations interactions, it would flow only for local deviatoric stress greater than a critical yield stress which depends on dislocation density. In a first set of fluid mechanics experiments in such a visco-plastic fluid, we showed that hot plumes would develop with a much thicker morphology than in newtonian fluids. Scaling laws derived from the experiments tightly relate the buoyancy and diameter of the hot plumes to the value of the yield-stress, as well as to the mantle microstructure (such as dislocation density and vacancy concentration). Yield stress values between 1 and 10 MPa, implying dislocation densities between 108 and 1010 m−2, would be sufficient to explain the thick plumes morphology observed in seismic tomography images; while low vacancy concentrations could explain the 1000 km-depth horizon also seen in tomography. 

In a second set of experiments, we show that the existence of a yield stress in a Bridgmanite lower mantle will also act as a filter regarding slab penetration in the lower mantle. Given slab buoyancy, a typical slab, 100 km-thick, could not overcome the lower mantle yield stress. So most of single slabs would be expected  to stagnate in the transition zone. However a pile of folded slab with a typical thickness around 400 km would have sufficient buoyancy and would penetrate into the lower mantle. This could explain the seismic tomographic observations regarding slabs in the transition zone and in the lower mantle, without the need to invoke a compositional stratification there.
Singularities in 2D flows: The Tale of Two Branch Points
Authors: Dyachenko Sergey , Dyachenko Alexander , Zakharov Vladimir
Published: March 2022

We consider the classical problem of 2D fluid flow with a free boundary. Recent
works strongly suggest that square--root type branch points appear naturally in
2D hydrodynamics. We illustrate how the fluid domain can be complemented by a
"virtual'' fluid, and the equations of motion are transplanted to a branch cut (a vortex sheet)
in the conformal domain. A numerical and theoretical study of the motion of
complex singularities in multiple Riemann sheets is suggested.

Unlike preceding works for dynamics of singularities: the short branch cut approximation,
and the study of viability of meromorphic solutions in fluid dynamics, the present approach
neither simplifies the equations of fluid flow, nor uses local Laurent expansions. Instead
the new approach is based on analytic functions and allows construction of global solutions
in 2D hydrodynamics.

A natural extension of the approach considers fluid flows described by many pairs
of square--root branch points.

Supported by RSF Grant 19-72-30028
Consistency and variability of spatial and temporal patterns of parameter dominance on four simulated hydrological variables in mHM in a large basin study
Authors: Guse Björn , Lüdtke Stefan , Rakovec Oldrich , Thober Stephan , Wagener Thorsten , Samaniego Luis
Published: March 2022

Model parameters are implemented in hydrological models to represent hydrological processes as accurate as possible under different catchment conditions. In the case of the mesoscale Hydrological Model (mHM), its parameters are estimated via transfer functions and scaling rules using the Multiscale Parameter Regionalization (MPR) approach [1]. Hereby, one consistent parameter set is selected for the entire model domain. To understand the impact of model parameters on simulated variables under different hydrological conditions, the spatio-temporal variability of parameter dominance and its relationship to the corresponding processes needs to be investigated.

In this study, mHM is applied to more than hundred German basins including the headwater areas in neighboring countries. To analyze the relevance of model parameters, a temporally resolved parameter sensitivity analysis using the FAST algorithm [2] is applied to derive dominant model parameters for each day. The temporal scale was further aggregated to monthly and seasonal averaged sensitivities. In analyzing a large number of basins, not only the temporal but also the spatial variability in the parameter relevance could be assessed. Four hydrological variables were used as target variable for the sensitivity analysis, i.e. runoff, actual evapotranspiration, soil moisture and groundwater recharge.

The analysis of the temporal parameter sensitivity shows that the dominant parameters vary in space and time and in using different target variables. Soil material parameters are most dominant on runoff and recharge. A switch in parameter dominance between different seasons was detected for an infiltration and an evapotranspiration parameter that are dominant on soil moisture in winter and summer, respectively. The opposite seasonal dominance pattern of these two parameters was identified on actual evapotranspiration. Further, each parameter shows high sensitivities to either high or low values of one or more hydrological variable(s). The parameter estimation approach leads to spatial consistent patterns of parameter dominances. Spatial differences and similarities in parameter sensitivities could be explained by catchment variability.

The results improve the understanding of how model parameter controls the simulated processes in mHM. This information could be useful for more efficient parameter identification, model calibration and improved MPR transfer functions.

 

References

[1] Samaniego et al. (2010, WRR), https://doi.org/10.1029/2008WR007327

[2] Reusser et al. (2011, WRR), https://doi.org/10.1029/2010WR009947
A new ice shelf melt model that accounts for freshwater discharge and application to Denman Glacier, East Antarctica
Authors: Pelle Tyler , Jenkins Adrian , Dow Christine , Greenbaum Jamin
Published: March 2022

Ice shelf basal melting is the primary mechanism by which the Antarctic Ice Sheet loses mass. While ocean forcing is the principal driver of basal melting, recent evidence suggests that localized melt maxima are located along deep grounding lines where large quantities of subglacial water are being discharged into sub-ice shelf cavities. As any change in the configuration of the grounding line can drastically influence the stress regime of the entire upstream grounded glacier, it is crucial we resolve this subglacial discharge-driven melting in a basal melt rate parameterization that can be used in standalone ice sheet models. Here, we extend the application of a 1D ocean and subglacial discharge driven melt parameterization into a 2D ice sheet model and apply it in forward simulations of Denman Glacier, East Antarctica.  Using subglacial hydrology model outputs to constrain the discharge inputs, we find that this parameterization resolves both local maxima and the large-scale spatial distribution of melt beneath the ice shelves buttressing Denman, Totten, Thwaites, and Pine Island glaciers. In the forward simulations of Denman Glacier, the melt contribution from subglacial discharge is required to reproduce contemporary patterns of grounding line retreat and rates volume loss. Under realistic 21st century ocean and subglacial forcing scenarios, Denman and Scott glaciers undergo largescale retreat and Denman Glacier retreats upstream to a ~10 km prograde section of bed topography upon which the grounding line stabilizes. However, under enhanced forcing, it is possible that Denman’s grounding line can overcome this topographic high and retreat inland into the deepest submarine trench on Earth beyond 2100
Long term wind speed and wind power change analysis over South Greenland using the regional climate model MAR.
Authors: Lambin Clara , Fettweis Xavier , Ernst Damien , Kittel Christoph
Published: March 2022

Fighting global warming implies replacing fossil fuels by renewable energy sources. Wind has the benefit to be an easily accessible and infinitely renewable resource but is not evenly distributed in space and time. A solution to prevent energy scarcity in a decarbonised world would be the building of a global interconnected grid that provide populated regions with electricity generated in remote but resourceful areas. In this context, it has appeared in previous studies that Greenland and Europe have complementary wind regimes. In particular, the southern tip of Greenland, Cape Farewell, has gained increasing interest for wind farm development as it is one of the windiest places on Earth. In order to gain new insights about future wind speed variations over South Greenland, the Modèle Atmosphérique Régional (MAR), validated against in situ observations over the ice-free area where wind turbines are most likely to be installed, is used to built climate projections under the emission scenario SSP 5-8.5 by downscaling an ensemble of CMIP6 earth system models (ESMs). These projections enable to assess the long term wind speed and maximum wind power change between 1981 and 2100 over Cape Farewell, quantified with the help of a linear regression. It appears from this analysis that, during this period over the ice-free area, the annual wind speed is expected to decrease of ~-0.8 m/s at 100m a.g.l. This decrease is particularly marked in winter while in summer, wind speed acceleration occurs along the ice sheet margins. An analysis of two-dimensional wind speed change at different vertical levels indicates that this decrease is likely due to synoptic circulation change, while in summer, the katabatic winds gowing down the ice sheet are expected to increase due to an enhaced temperature contrast between the ice sheet and the surroundings. As for the mean annual maximum wind power a turbine can yield, a decrease of ~-300.5 W is to be expected over the ice-free area of Cape Farewell between 1981 and 2100 at 100m a.g.l. Again, the decrease is especially marked in winter. Considering the very high winter wind speeds occuring in South Greenland which can cut off wind turbines if too intense, the projected wind speed decrease might be beneficial for the establishment of wind farms near Cape Farewell.
A New Hot-Stage Microscopy Method for Measuring Temperature-Dependent Viscosities of Secondary Organic Aerosol 
Authors: Kiland Kristian , Marroquin Kevin , Xu Shaun , Smith Natalie , Nizkorodov Sergey , Bertram Allan
Published: March 2022

The viscosity of secondary organic aerosols (SOA) is needed to predict their influence on air quality, climate, and atmospheric chemistry.  Many techniques have been developed to measure the viscosity of micrometer-sized materials at room temperature, however, few techniques are able to measure viscosity as a function of temperature for these small sample sizes. SOA in the troposphere experience a wide range of temperatures, so measurement of viscosity as a function of temperature is needed. To address this need, a new method was developed based on hot-stage microscopy (HSM) combined with fluid dynamics simulations. To validate our technique, the viscosity of a literature standard was reproduced with good accuracy. As an application to atmospheric aerosols, the viscosity as a function of temperature for lab-generated farnesene SOA was measured, with values ranging from 3.4 × 106 Pa s at 51°C to 2.6 × 104 Pa s at 67°C.
Intraplate seismicity controlled by lithospheric-mantle strength: the Ireland and Britain case study
Authors: Lebedev Sergei , Arroucau Pierre , Grannell James , Bonadio Raffaele
Published: March 2022

Stable continental areas—those largely unaffected by currently active plate-boundary processes—undergo little deformation and feature low seismicity rates. Notable exceptions, such as the well-known large earthquakes in the central United States or the Fennoscandian Craton, are rare but highlight the importance of understanding the seismicity in low-strain regions. One long-standing question, debated for over a century, relates to the seismicity of Ireland. Why is it much lower than that in the neighbouring Britain, even though they were assembled in the same Caledonian orogeny, share many of the ancient tectonic boundaries, and are subjected to similar tectonic stresses? Our new catalogue of Ireland’s seismicity, produced using the greatly improved seismic station coverage of the island over the last decade, shows many more micro-earthquakes than known previously but confirms the much lower seismicity rates in Ireland compared to Britain.

Comparing the distribution of seismicity with high-resolution, surface-wave tomography (performed using the abundant new data) we observe that areas with thicker, colder lithosphere feature lower seismicity than those with thinner lithosphere. This must be because the thicker and colder lithosphere is mechanically stronger and less likely to deform, compared to the thinner and weaker lithosphere under the same tectonic stress. According to the new tomography, Ireland has thicker lithosphere than most of Britain, which can explain its lower seismicity rates. The thinnest lithosphere in Ireland is found in the north of the island, in Co Donegal, and this is where most of Ireland’s micro-seismicity occurs. A similar relationship between the lithospheric thickness and seismicity rates is observed in Britain, with the London Platform in the southeast of the island showing thick lithosphere and low seismicity.

Together, lithospheric tomography and seismicity maps thus offer a solution to a seismo-tectonic puzzle first formulated in the 19-th century. Evidence of the lithospheric mantle controls on earthquake occurrence can be seen elsewhere around the world as well. The improving accuracy of the tomographic imaging of the lithosphere presents a useful new line of evidence on the mechanisms that control the regional distributions of intraplate earthquakes.
Global observations of accelerated glacier change over the past decade using TanDEM-X remote sensing
Authors: Malz Philipp , Sommer Christian , Farías David , Seehaus Thorsten , Braun Matthias
Published: March 2022

The past 7 years have been the warmest consecutive period on record by a clear margin, according to the Copernicus climate data archive. Glaciers and icecaps react with accelerated adaptation to those drastically changing environmental conditions. Profound knowledge about their status and ongoing changes in terms of quantifiable ice loss is crucial to predict the future of those vital sources of ecosystems and populations. The contribution of remote sensing techniques has become indispensable to complement in situ observations and thus letting modelled predictions emerge.

Over the past decade the satellite mission of TanDEM-X has accomplished the goal of covering the terrestrial surface with high resolution SAR imaging at least twice. We selected suitable datasets from that mission archive to calculate Digital Elevation Models (DEMs). Comparing the elevation datasets on Glaciers and Icecaps with the temporal baseline of the two global acquisition periods (2012-2018) allows for the calculation of elevation and volume change.

Over the last year we calculated annual elevation change rates in over 30 000 satellite image scenes to present a global picture of Glacier change that corresponds to the TanDEM-X mission time. We compare these to previous changes which we calculated in respect to SRTM elevation (2000-2012) where possible and/or existing studies. The first results for Arctic Russia and Patagonia show increased rates of volume loss from 70 to exceeding 100 percent, compared to results from the earlier decade. Whereas for the regions of High Mountain Asia we find more moderate acceleration. The presentation aims at providing a comprehensive overview of surface elevation and volume changes for most Randolph Glacier Inventory regions.
What control hydrothermal dolomitization? Experimental replacement with time-step monitoring by X-ray microtomography
Authors: Lefeuvre Benjamin , Beaudoin Nicolas , Centrella Stephen , Callot Jean-Paul
Published: March 2022

Hydrothermal dolomitization of limestones, i.e. fluid-mediated stoichiometric substitution Casolid ↔ Mgfluid replacing CaCO3 with dolomite CaMg(CO3)2, plays a key role in the structural integrity and permeability of the rock that can have dramatic consequences for earthquake hazards, reservoir quality, civil engineering. This particular reaction creates km-scale geobodies usually related to ore deposits or hydrocarbons, and being very efficient bodies for carbon sequestration. As for numerous hydrothermal reactions, various chemo-physical models built from chemical analysis and experiments in analogous replacement compete to explain this mineralogical transformation. Yet, relevant comparison to natural systems remains limited, and the way to explain the creation of large dolomite geobodies remains unexplained. Only recently dolomitization has been successfully recreated in laboratory under a reasonable timescale [1, 2], a few hours to a week according to the fluid reactivity.

This project proposes to use non-destructive imagery methods (xCT) coupled with hydrothermal reactors to reproduce dolomitization in-situ. We choose to study two natural samples representing two end-members: (1) Carrara marble which contains homogeneous polymineralic calcite grains; (2) Layens limestones (French Pyrenees) which is a marble already dolomitized naturally. These two samples were incubated in hydrothermal Teflon reactors in a Mg-enriched aqueous solution [3] at 200°C for different time steps. Microtomography have been acquired at various stages of the reaction, allowing us to track the propagation of the dolomitization front within the samples. This approach allows us to mimic natural dolomitization over time and provides a detailed study of the morphology of the reaction front between calcite and dolomite. Quantifying and describing the microstructures related to replacements (pores, fractures, grains orientation and size) help unravelling how dolomitization can propagate in nature.

 

 

References

[1] L. Jonas, T. Müller, R. Dohmen, L. Baumgartner, B. Pultlitz, Geology (2015)

[2] J. Weber, M. Cheshire, M. Bleuel, D. Mildner, Y-J. Chang, A. Ievlev, K. Littrell, J. Ilavsky, A. Stack, L. Anovitz, Geochimica et Cosmochimica Acta 303 (2021)

[3] V. Vandeginste, O. Snell, M. Hall, E. Steer, A. Vandeginste, Nature communications (2019)
Observationally calibrating snow-on-sea-ice model free parameters and estimating uncertainties using a Markov Chain Monte Carlo method
Authors: Cabaj Alex , Kushner Paul , Petty Alek
Published: March 2022

Snow on Arctic sea ice plays many roles in Arctic climate feedbacks; in particular, through its impact on sea ice. Snow can have many, sometimes contrasting effects on sea ice thickness and extent. For example, during the ice growth season, snow can inhibit ice growth by insulating the ice from the cold atmosphere. Conversely, snow can allow sea ice to persist longer during the melt season, due to its high albedo. Furthermore, estimates of snow depth on Arctic sea ice are a key input for deriving sea ice thickness from satellite lidar altimetry measurements, such as those from ICESat-2. Due to the logistical challenges of making measurements in as remote a region as the Arctic, snow depth on Arctic sea ice is difficult to observationally quantify.

To provide widespread estimates of the depth and density of snow on Arctic sea ice, models such as the NASA Eulerian Snow On Sea Ice Model (NESOSIM) can be used. The latest version of NESOSIM, version 1.1, is a 2-layer three-dimensional model with simple representations of snow accumulation, wind packing, loss due to blowing snow, and redistribution due to sea ice motion. Relative to version 1.0, among other changes, NESOSIM 1.1 features an extended model domain and reanalysis snowfall input from ERA5 scaled to observed snowfall derived from CloudSat satellite radar measurements.

The free parameters in NESOSIM, which dictate the strength of the wind packing (densification) and blowing snow loss processes, cannot be directly constrained to observations. We present an indirect calibration of these free parameters, by calibrating NESOSIM output to observations from airborne snow depth observations from Operation IceBridge and in situ CRREL-Dartmouth snow buoy measurements, as well as historical Soviet drifting station density measurements, using a Metropolis Markov Chain Monte Carlo (MCMC) approach. This approach produces estimates of the free parameters and their uncertainty distributions, from which model snow depth and density uncertainties can be estimated. We find that introducing stricter observational constraints in the calibration produces narrower snow depth uncertainty distributions from NESOSIM. We then examine the impact of these uncertainties on sea ice thickness derived using NESOSIM output and freeboard measurements from ICESat-2.
Projected increases in Antarctic snow accumulation from CMIP6 to 2300
Authors: Trayling Natalie , Lowry Daniel , Dadic Ruzica
Published: March 2022

As the atmosphere warms in response to increasing greenhouse gas emissions, snow accumulation over the Antarctic Ice Sheet is projected to increase over the next century. Furthermore, short-term emissions scenarios are also expected to have long-term impacts on ice sheet mass balance for centuries to come. Here, we analysed the extended runs of the Coupled Model Intercomparison Project’s Sixth Phase (CMIP6) to investigate the consequences of emissions scenarios on Antarctic surface mass balance until 2300. Unlike the Arctic, which shows a regime shift from snow-dominated precipitation to rain-dominated precipitation, snow accumulation continues to outpace ablation over the Antarctic Ice Sheet through the year 2300, even under the high emissions Shared Socioeconomic Pathway 5-8.5 scenario. The positive relationship between precipitation and temperature increases through time at both high elevation in the continental interior as well as at the coastal margins of the ice sheet. Under high emissions, although rainfall is projected in some vulnerable regions, such as Thwaites Glacier, overall surface mass balance remains positive and increases through time. In corresponding ice sheet model experiments using the Parallel Ice Sheet Model, the sea level compensation of this increased surface mass balance is as high as 10 cm by 2100 and 1.8 m by 2300, though considerable intermodel spread exists. These model results suggest that mass loss of the ice sheet will continue to be dominated by ocean driven-melting rather than melting of the ice sheet surface for the next centuries.
A Novel Approach to Estimate Snowfall over an Alpine Terrain via the Assimilation of Sentinel-1 Snow Depth Observations
Authors: Girotto Manuela , Formetta Giuseppe , Azimi Shima , Modanesi Sara , De Lannoy Gabrielle , Lievens Hans , Rigon Riccardo , Massari Christian
Published: March 2022

Estimating snowfall over mountain regions is an extremely challenging task due to the high variability of spatial and temporal precipitation gradients. Traditional methods to estimate snowfall include in-situ gauges, doppler weather radars, satellite radars and radiometers, numerical modeling and reanalysis products. Each of these methods, alone, is unable to capture the complex orographic precipitation. For example, in-situ gauges are often too sparse and lead to significant interpolation errors; radar beams are shielded by the complex mountainous terrains; satellite estimates are sub-optimal over snowy mountains regions; while the physical parameterization of mountainous orography remains challenging for estimating precipitation in numerical models. A potential method to overcome model and observational shortcomings in precipitation estimation is land surface data assimilation, which leverages the information content in both land surface observations and models while minimizing their limitations due to uncertainty. Recently, the ESA and Copernicus Sentinel-1 constellation has been used to map snow-depth across the Northern Hemisphere mountains with 1 km spatial resolution by exploiting C-band cross-polarized backscatter radar measurements. This work aims at characterizing and estimating snowfall precipitation errors over an alpine watershed located in Trentino Alto Adige, Italy. We derive the snowfall errors via the data assimilation of 1 km Sentinel-1 snow-depth observations within a numerical model. The data assimilation applies a particle batch smoother to the coupled snow-17 and Sacramento hydrological models.
Characterization of Atotonilco geothermal area, Veracruz, Mexico
Authors: Baizabal Gómez Emma Daira , Jácome Paz Mariana Patricia , Pérez Zarate Daniel , de la Fuente Rivera Juan Ramón , Prol Ledesma Rosa María
Published: March 2022

Geothermal high enthalpy resources can be an important potential source to satisfy Mexico’s energy requirements ; nevertheless, low and moderate enthalpy resources may contribute through the direct uses to replace fossil fuels. In both cases, the exploitation of geothermal resources are an important factor inthe energy transition that the whole world strives to achieve. Furthermore, it has an important social impact in the communities, where the use of geothermal energy can bring considerable benefit. In this work, a geothermal characterization with a geographic approach is presented for the “Atotonilco” (hot water in native language) town in Calcahualco municipality of Veracruz state (eastern México). The surface manifestations in the area are calcium-carbonate warm springs with flows from 1 to 12 liters per second. The temperature at depth was estimated between 70°C and 74°C with the calcedony geothermometer, which corresponds to a low enthalpy resource. A preliminary conceptual model of the Atotonilco geothermal area, using all data and a list of the feasible direct uses applications are proposed. These proposals consider the social and economic characteristics of the study area that were observed during the field work. The recommended actions include dissemination of the results of this research, as an important contribution to the development of geothermal resources in Atotonilco town.

Keywords: Geothermal energy, environmental geography, renewable energy, direct use, geochemical exploration, geoscience dissemination.

Acknowledgment

Thanks to Dr. Ramón Espinasa Pereña for his technical support during the field work. Thanks to the Laboratory of Analytical Chemistry of the Institute of Geophysics, UNAM, especially to the QFB Olivia Cruz, M in Ing. Alejandra Aguayo and QFB Omar Neri, for carrying out the chemical analyzes of water presented here.