bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracing the transport of organic colloids in porous media using tailored poly(ethylene glycol)
Authors: Ritschel Thomas , Lehmann Katharina , Brunzel Michaela , Vitz Jürgen , Nischang Ivo , Schubert Ulrich , Totsche Kai
Published: March 2021

A large fraction of organic matter in natural aqueous soil solutions is given by molecules in sizes above one nanometer, which classifies them as colloids according to the IUPAC definition. Such colloids feature discernable mobility in soils and their transport is decisive for the cycling of carbon as well as the migration of nutrients or contaminants. Yet, their size-dependent hydrodynamics and functional diversity result in transport phenomena that are specific to colloids and, thus, largely differ from those observed for smaller substances. Still, tracers that appropriately represent small organic colloids are not available and the investigation of their transport in laboratory column experiments, in dependence of size and chemistry, remains difficult. To overcome this limitation, we tested if well-defined synthetic polymers in the colloidal size range are suitable as non-conventional tracers of colloidal transport. As polymer backbone, we selected poly(ethylene glycol) (PEG) due to its high water-solubility and established pathway of synthesis that permits tailoring of functional moieties to the fullest extent. An easy and sensitive detection in the aqueous phase became possible by using a fluorophore as starting group. After full characterization, we studied PEG adsorption to quartz, illite, goethite, and their mixtures in batch and column transport experiments. In numerical simulations, we successfully reconstructed and predicted PEG transport based on its physicochemical as well as hydrodynamic properties and, thus, show that PEG transport can be comprehensively and quantitatively studied. Considering also its low adverse effect on the environment, functional PEG therefore presents as promising candidate to be used as organic tracer, designable in the size range of natural organic (macro-)molecules (Ritschel et al., 2021).

References

Ritschel, T., Lehmann, K., Brunzel, M., Vitz, J., Nischang, I., Schubert, U., Totsche, K. U. (2021) Well-defined poly(ethylene glycol) polymers as non-conventional reactive tracers of colloidal transport in porous media. J. Colloid Interface Sci. 548, 592-601, doi: 10.1016/j.jcis.2020.09.056.
Irrigation management through a coupled energy-water balance and crop growth model driven by remote sensing data
Authors: Mancini Marco , Corbari Chiara , Ben Charfi Imen , Al Bitar Ahmad , Skokovic Drazen , Sobrino Jose , Branca Giacomo
Published: March 2021

The conflicting use of water is becoming more and more evident, also in regions that are traditionally rich in water. With the world’s population projected to increase to 8.5 billion by 2030, the simultaneous growth in income will imply a substantial increase in demand for both water and food. Climate change impacts will further stress the water availability enhancing also its conflictual use. The agricultural sector is the biggest and least efficient water user, accounts for around 24% of total water use in Europe, peaking at 80% in the southern regions.

This paper shows the implementation of a system for real-time operative irrigation water management at high spatial and temporal able to monitor the crop water needs reducing the irrigation losses and increasing the water use efficiency, according to different agronomic practices supporting different level of water users from irrigation consortia to single farmers. The system couples together satellite (land surface temperature LST and vegetation information) and ground data, with pixel wise hydrological crop soil water energy balance model. In particular, the SAFY (Simple Algorithm for Yield) crop model has been coupled with the pixel wise energy water balance FEST-EWB model, which assimilate satellite LST for its soil parameters calibration. The essence of this coupled modelling is that the SAFY provides the leaf area index (LAI) evolution in time used by the FEST-EWB for evapotranspiration computation while FEST-EWB model provides soil moisture (SM) to SAFY model for computing crop grow for assigned water content.

The FEST-EWB-SAFY has been firstly calibrated in specific fields of Chiese (maize crop) and Capitanata (tomatoes) where ground measurements of evapotranspiration, soil moisture and crop yields are available, as well as LAI from Sentinel2-Landsat 7 and 8 data. The FEST-EWB-SAFY model has then been validated also on several fields of the RICA farms database in the two Italian consortia, where the economic data are available plus the crop yield. Finally, the modelled maps of LAI have then been validated over the whole Consortium area (Chiese and Capitanata) against satellite data of LAI from Landsat 7 and 8, and Sentinel-2.

Optimized irrigation volumes are assessed based on a soil moisture thresholds criterion, allowing to reduce the passages over the field capacity threshold reducing the percolation flux with a saving of irrigation volume without affecting evapotranspiration and so that the crop production. The implemented strategy has shown a significative irrigation water saving, also in this area where a traditional careful use of water is assessed.

The activity is part of the European project RET-SIF (www.retsif.polimi.it).
Overcoming challenges in spatio-temporal modelling of large-scale (global) data
Authors: Brady Aoibheann , Rougier Jonathan , Ziegler Yann , Vishwakarma Bramha Dutt , Royston Sam , Chuter Stephen , Westaway Richard , Bamber Jonathan
Published: March 2021

Modelling spatio-temporal data on a large scale presents a number of obstacles for statisticians and environmental scientists. Issues such as computational complexity, combining point and areal data, separation of sources into their component processes, and the handling of both large volumes of data in some areas and sparse data in others must be considered. We discuss methods to overcome such challenges within a Bayesian hierarchical modelling framework using INLA.

In particular, we illustrate the approach using the example of source-separation of geophysical signals both on a continental and global scale. In such a setting, data tends to be available both at a local and areal level. We propose a novel approach for integrating such sources together using the INLA-SPDE method, which is normally reserved for point-level data. Additionally, the geophysical processes involved are both spatial (time-invariant) and spatio-temporal in nature. Separation of such processes into physically sensible components requires careful modelling and consideration of priors (such as physical model outputs where data is sparse), which will be discussed. We also consider methods to overcome the computational costs of modelling on such a large scale, from efficient mesh design, to thinning/aggregating of data, to considering alternative approaches for inference. This holistic approach to modelling of large-scale data ensures that spatial and spatio-temporal processes can be sensibly separated into their component parts, without being prohibitively expensive to model.
Climatic Extremes and Human Resilience: An Examination of Two Hydrographic Basins in the Great Basin (northern Nevada, USA)
Authors: Hall Mark
Published: March 2021

The purpose of this paper is to look at the prehistoric human settlement patterns in the northern Great Basin of the United States
in light of a variety of climate proxies.  The intent is to look at the response of Great Basin hunter-gatherers in response to extreme climatic events.  
Focus will be on two US Geological Survey designated hydrographic basins: the Black Rock Basin and 
the Truckee Basin.  The Black Rock Basin contains the Quinn River which originates in the Montanna Mountains and terminates into a seasonal lake
on the Black Rock playa.  The Truckee Basin contains the Truckee River which flows from Lake Tahoe in the Sierra Nevada range 
to the terminal Pyramid Lake.  

Radiocarbon dates from excavated archaeological sites in the two basins are used as a demographic and settlement proxy.  Climate proxies
from the two basins include: oxygen isotope data from Pyramid Lake, pollen cores from Mud Meadows spring and Summit Lake, and tree ring 
data from the Jackson Mountains. 

Both basins see initial human settlement during the Younger Dryas period, with a growth in population/settlements through 8000 BP. After
approximately 7800 BP, there is a paucity of dated sites until approximately 4000 BP.  Whether this is due to the 8.2 kya BP climatic event and/or
the Mount Mazama volcanic eruption, is uncertain.  Oxygen isotope data from Pyramid Lake does indicate a period of hyper-aridity throughout the
northern Great Basin between ca. 8-4 kya BP.  The aridity declines after 4 kya based on the oxygen isotope data, and settlement in the 
two basins increases.  With the onset of the Late Holocene Drought, ca. 2500 BP, population/settlement declines are seen except around 
major lakes, north of 42N latitude, and elevations above 2000m. After 2000 BP, population/settlement increases throughout both basins.  Notable
increases of population/settlement occurs in the Late Antique Little Ice Age and continues throughout the Medieval Climatic Anomaly (MCA). Environmental proxy data indicates the MCA was a period of extreme aridity in the northern Great Basin. Despite ameorilating conditions in both basins after the MCA and in the Little Ice Age, population/settlement declines after circa 700 BP.    
Characteristics, distribution and susceptibility of natural and human-induced landslides in a tropical mountainous region: the Rift flank west of Lake Kivu (DR Congo)
Authors: Maki Mateso Jean-Claude , Bielders Charles , Monsieurs Elise , Depicker Arthur , Smets Benoît , Tambala Théophile , Bagalwa Mateso Luc , Dewitte Olivier
Published: March 2021

Tropical mountainous regions are often identified as landslide hotspots with particularly vulnerable populations. Whereas both natural (e.g., rainfall, lithology) and anthropogenic (e.g., deforestation, mining) factors are expected to be involved in landslide occurrence, the relative importance of such factors remains poorly documented. The objective of this study is to understand the role played by natural and anthropogenic factors in the occurrence of landslides in the Rift Flank west of Lake Kivu in DR Congo. First, we inventoried 2856 landslides of various types using Google Earth imagery, high resolution topographic data, historical aerial photographs from1950’sand intense field surveys. We made a distinction between old and recent deep-seated landslides, shallow landslides and mining-related landslides. The difference in susceptibility patterns and in size distributions between old and recent deep-seated landslides indicates that natural factors contributing to their occurrence were either different or changed over time. The shallow landslides are all recent. The susceptibility analysis shows that their regional pattern is mainly controlled by forest dynamics and the presence of roads. The occurrence of shallow landslides in forest areas, i.e. in natural environments, strongly increases with slope gradient. In areas with similar topographic conditions where deforestation has occurred since the 1950’s, shallow landslides are more frequent, but of smaller size. This size reduction is attributed to the decrease of regolith cohesion due to forest loss, which allows a smaller minimum critical area for landsliding. In areas that were already deforested in 1950’s, shallow landslides are less frequent, larger, and occur on less steep slopes. This suggests a combined role between regolith availability and soil management practices that influence erosion and water infiltration. Landslides associated with mining activities are larger than shallow landslides but smaller than the recent deep-seated instabilities. They are not well predicted by the susceptibility models, showing that they respond to environmental factors that are not present under natural conditions. This research highlights the importance of human activities on the occurrence of landslides and the need to consider this context when studying hillslope instability patterns in regions under anthropic pressure.

 

Keywords: landslide processes, multi-temporal inventory, historical deforestation, mining and quarrying, susceptibility assessment, Africa
Observational and Modeling Analysis of Land-Atmosphere Interactions over Adjacent Irrigated and Rainfed Cropland During the GRAINEX Field Campaign.
Authors: Rappin Eric , Mahmood Rezaul , Udaysankar Nair , Pielke Sr. Roger
Published: March 2021

Continued scientific study has revealed that land use and land cover change play a key role in climate and that the application of irrigation is an important biogeophysical contributor to climate modification across spatial scales. The Great Plains Irrigation Experiment (GRAINEX) was conducted in the spring and summer of 2018 to investigate Land-Atmosphere interactions just prior to and through the growing season across adjacent, but distinctly unique, soil moisture regimes (contrasting irrigated and rainfed fields). GRAINEX was uniquely designed for the development and analysis of an extensive observational dataset for comprehensive process studies of Land-Atmosphere interactions, by focusing on irrigated and rainfed croplands in a ~100 x 100 km domain in southeastern Nebraska. Observation platforms included multiple NCAR EOL Integrated Surface Flux Systems and Integrated Sounding Systems, NCAR CSWR Doppler Radar on Wheels, 1200 radiosonde balloon launches from 5 sites, the NASA GREX airborne L-Band radiometer, and 75 University of Alabama-Huntsville Environmental Monitoring Economic Monitoring Sensor Hubs (EMESH mesonet stations). The presentation will provide an overview of the field campaign, the dataset collected, and investigate the contrast of L-A intractions across an irrigation gradient through observations and mesoscale/microscale modeling on timescales ranging from the diurnal to the seasonal. Attention will be given to how variations in the land surface state, as a function of irrigation fraction, impacts near-surface meteorology and atmospheric boundary layer evolution at local and regional scales.
The salt route through time and space: Following horizontal and lateral intrusion of brackish surface water into a natural floating root mat and its plant community.
Authors: Huizinga Milou , Aerts Rien , van Logtestijn Richard S.P. , van der Zee Sjoerd E.A.T.M. , Witte Jan-Philip M.
Published: March 2021

Salinizing surface water is a large problem worldwide. In many areas agriculture is dependent on surface water irrigation, but there is an increasing fresh water scarcity. Due to natural and anthropogenic processes the salt concentration of surface water has risen and this problem is predicted to increase in the future. Prioritizing on when fresh water is needed and when brackish or salt water could be possible is therefor necessary. However, this holds not only for agricultural systems, but also for natural areas which are currently overlooked. In deltaic areas – such as The Netherlands – sea water is flowing further inland via rivers during summer. In addition to this, in the hinterland, artificial drainage of low-lying polders leads to a salt groundwater surplus that is discharged into rivers and surface water reservoirs. These processes lead to salinization and could potentially affect plant biodiversity and ecosystem functioning in surface water fed ecosystems, wetlands, and riparian zones. One of such a surface water fed ecosystems is an abandoned turf extraction site ‘De Botshol’ in The Netherlands. Floating root mats have developed from peat baulks into the open water of old turf ponds. These mats can harbor a great deal of protected terrestrial, typically glycophyte (i.e. optimally encountering < 300 mg Cl.l-1), plant species related to a floating fen habitat. Currently the surface water quality of Botshol is brackish and this provided us with an opportunity to follow the local salt route through space and time. Surface water salt concentrations fluctuated slightly between winter-spring: 1400 mg Cl.l-1 and summer-autumn: 1900 mg Cl.l-1 and we linked this to root zone processes and the plant community. We used a pore water extraction setup using micro- and macrorhizons placed at 30 – 60 – 200 cm from the edge of a floating root mat. Along this transect we measured at 10 – 25 – 50 – 70 cm depth. Via this setup we were able to find that the root zone salt concentrations fluctuated with surface water concentration, however there was a substantially lower salt concentration in the soil layer. Root zone concentrations still reached above 500 mg Cl.l-1 and this might explain differences in community composition in comparison with a fresh floating fen ecosystem (e.g. ‘Nieuwkoopse Plassen’, The Netherlands). We present this work to empirically link hydrology and ecology in relation to surface water salinization, but also to practically inform water boards and nature managers to understand possibilities and limitations of surface water salinization in relation to fen restoration and protection.
Simulating airborne ‘snow walls’ of Antarctica using CRYOWRF v1.0
Authors: Sharma Varun , Gerber Franziska , Lehning Michael
Published: March 2021

When a well-developed, high velocity katabatic flow draining down the ice sheet of Antarctica reaches the coast, it experiences an abrupt and rapid transition due to change in slope resulting in formation of a hydraulic jump. A remarkable manifestation of the hydraulic jump, given the ‘right’ surface conditions, is the large-scale entrainment and convergence of blowing snow particles within the hydraulic jump. This can result in formation of 100-1000 m high, highly localized ‘walls’ of snow in the air in an otherwise cloud-free sky.

Recent work by Vignon et al. (2020) has described in detail, the mechanisms resulting in the formation of hydraulic jumps and excitation of gravity waves during a particularly notable event at the Dumont d’Urville (DDU) station in August 2017. They used a combination of satellite images, mesoscale simulations with WRF and station measurements (including Micro Rain Radars) in their study, notably relying on the snow wall for diagnosing and quantifying the hydraulic jump in satellite images. On the other hand, relatively less importance was given towards the surface snow processes including the transport of snow particles in the wall.

In this presentation, we present results from simulations done using the recently developed CRYOWRF v1.0 to recreate the August 2017 episode at DDU and explicitly simulate the formation and the dynamics of the snow wall itself. CRYOWRF enhances the standard WRF model with the state-of-the-art surface snow modelling scheme SNOWPACK as well as a completely new blowing snow scheme. SNOWPACK essentially acts as a land surface model for the WRF atmospheric model, thus making a quantum leap over the existing snow cover models in WRF. Since SNOWPACK is a grain-scale snow model, it allows for the proper formulation of boundary conditions for simulating blowing snow dynamics.

Results show the formation of the snow wall due to large scale entrainment over a wide area of the ice sheet, the mass balance of the snow wall within the hydraulic jump and finally, the destruction of the snow wall and the ultimate fate of all the entrained snow. We also show results for the influence of the snow wall on the local surface radiation at DDU. Overall, we test the capabilities of CRYOWRF to simulate such a complex phenomenon and highlight possible applications now feasible due the tight coupling of an advanced snow cover model and a multi-scale, non-hydrostatic atmospheric flow solver.

Reference:

Vignon, Étienne, Ghislain Picard, Claudio Durán-Alarcón, Simon P. Alexander, Hubert Gallée, and Alexis Berne. " Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica". Journal of the Atmospheric Sciences 77.4 (2020): 1295-1312. <>.
Investigating the drag-based model parameters through statistical methods
Authors: Napoletano Gianluca , Foldes Raffaello , Berrilli Francesco , Calchetti Daniele , de Gasperis Giancarlo , Del Moro Dario , Kumar Tiwari Ajay , Teunissen Jannis , Camporeale Enrico
Published: March 2021

Due to their simplicity and relatively short computational time, empirical models for Solar Wind Transients, based on a restricted number of assumptions and on the values of a small set of parameters, play an important role in Space Weather forecasting. For this reason, an optimal choice of values for the model parameters is of critical importance in this approach. In this work, we compiled a list of CME events by merging and cross-referencing several databases and made use of such experimental data to evaluate statistical distributions for the model parameters of a chosen forecasting model for ICME arrivals, namely the Drag-Based model. Our results lead to several considerations and refinements to be implemented in the future in this and other forecasting models.
Ambient noise waveform imaging of Yellowstone's magmatic system
Authors: Maguire Ross , Chen Min , Schmandt Brandon , Jiang Chengxin , Wilgus Justin , Li Jiaqi
Published: March 2021

Understanding important characteristics of Yellowstone's magmatic system such as the melt fraction, composition, and geometric organization of melt are critical for improving our knowledge of volcanic processes and assessing the potential for future eruptions.  While previous tomographic images have provided much insight into the magmatic system, imaging results are complicated by an incomplete understanding of how large crustal magmatic systems affect seismic waveforms. In particular, tomographic studies based on asymptotic methods may underestimate the seismic wave speed anomaly of the magma reservoir because first arriving energy may be diffracted around strong low wave speed anomalies. Here, we present a high-resolution shear wave speed model of Yellowstone’s crust and uppermost mantle structure, based on the most up to date dataset of ambient noise correlation functions from broadband stations deployed in the Yellowstone region over the past two decades. This model serves as the starting point for an adjoint inversion, which has potential to improve resolution by incorporating more accurate sensitivity kernels based on realistic wave propagation physics. We discuss our adjoint tomography methodology and present the first model iterations. Continued iterations promise to sharpen features in the model which can provide new inferences into the present state of Yellowstone’s magmatic system.
Kinematics of the Sea of Marmara using GPS, InSAR and underwater geodetic data: Possible Influence of Crustal Heterogeneity
Authors: Özbey Volkan , Özeren Mehmet Sinan , Henry Pierre , Cavalié Olivier , Le Pichon Xavier , Klein Elliot , Tarı Ergin , Galgana Gerald
Published: March 2021

Seismological studies on the western part of the North Anatolian Fault (NAF) revealed the possibility that it may constitute a bimaterial interface at various locations. One evidence for this came from Karadere and Mudurnu segments where Fault Zone Head Waves (FZHW) and Fault Zone Reflected Waves (FZRW) indicated bimaterial interfaces and damage zones of various depth ranges. These were often interpreted as factors affecting various aspects of rupture propagation velocities and rupture lengths. In addition, the difference in crustal structure between the northern shore of the Sea of Marmara and the deep basins may results in an effective rigidity contrast across the Main Marmara Fault, at least in its Eastern part from Kumburgaz Basin, to the entrance of Izmit Gulf. This could result in reduced elastic loading of the northern block, leading to an underestimation of slip deficit in geodetic models. However, the problem was never looked at using multiple constraints at the same time such as the GPS, InSAR and underwater geodetic data. In this study we use the interseismic slip distribution on the westernmost section of the NAF (comprising largely the Main Marmara Fault and the bifurcation zone to the east of the Izmit Gulf) obtained using a block model as a reference model and use a finite element model to test the perturbations to this model as a function of the elastic moduli contrasts across the fault. We are testing the case where there is a bimaterial interface all the way from Izmit Gulf to Kumburgaz and then a lack of such a contrast in the Central Basin. We are also investigating a scenario where the Ganos region also has bimaterial interface (but reverse in its nature).
Imaging azimuthal anisotropy in the alpine crust from ambient noise beamforming.
Authors: Soergel Dorian , Pedersen Helle , Bodin Thomas , Paul Anne , Stehly Laurent
Published: March 2021

Noise cross-correlations provide a good azimuthal coverage, limited only by the distribution of noise sources and the layout of the stations used. It is therefore a promising method to constrain azimuthal anisotropy. As noise cross-correlations consist mainly of surface waves, they are especially sensitive to the crust and provide good depth constraints, as opposed to SKS-splitting data that are more sensitive to the upper mantle. We use the AlpArray network as well as stations from permanent networks all across Europe to perform time-domain beamforming on noise cross-correlations. The extent and density of the AlpArray network allows us to obtain reliable measurements all across the Alps. We divide the area in smaller zones using all stations outside the zone as sources and all stations inside as a sub-array for beamforming. This allows us to estimate the quality of our measurements in a region where strong lateral heterogeneities make measurements challenging, by estimating the magnitude of bias due to heterogeneities using the cos(theta) amplitude and evaluating uncertainties with bootstrap. This way, we measure Rayleigh wave azimuthal anisotropy in several period bands between 15 s and 60 s period. Inversion of dispersion curves in specific areas allows us to constrain the depth of the observed anisotropy. The results are broadly similar to results from SKS-splitting as they are generally parallel to the mountain belt. However, we observe lower anisotropy at short periods (40 seconds and less) in the Alps themselves than in surrounding regions. We also observe several structures in the crust that are not observed with SKS-splitting data. The most striking is a strong and spatially coherent NE-oriented anisotropy to the NW of the Alps that is possibly related to Variscan inheritance (at 40 seconds and less, in the upper and lower crust).  In the Northern Apennines, we observe anisotropy perpendicular to the belt at 30 s period (middle crust) that correlates well with an area of strong radial anisotropy recently observed by Alder et al (in review) at 30 km depth. 
The impact of compaction of clastic sediments on fluvial-dominated delta morphology
Authors: Valencia A. Aulia , Storms J.E.A. (Joep) , Walstra Dirk-Jan , van der Vegt Helena , Jagers H.R.A. (Bert)
Published: March 2021

Only a limited amount of data is available to quantify the impact of syn-depositional compaction on delta depositional patterns. In this study, we investigate numerically how different scenarios for compaction rate (0 - 10 mm yr-1) drives morphological variations in mud- and sand-rich fluvial-dominated deltas. To do this, a 1D grain-size dependent compaction model was implemented into the open-source Delft3D. This implementation allows deposited sediment to decrease in thickness over time due to the accumulation of newly deposited sediments above. The resultant sedimentary deposits of a prograding delta are post-processed to highlight the changes in depositional patterns under different compaction scenarios. Deposits are classified into sub-environment (e.g., delta top, delta front, and pro delta). The delta top geometry (e.g., area, shape, and rugosity) and the distribution of sediment between different sub-environments are compared. The modeling results verify that the larger compaction-induced subsidence affects accommodation provision. We show that this results in more significant sediment deposition and more evenly distributed sediment across the delta top. Larger compaction results in a smaller area with a more semi-circular shape and less rugose delta top. The modeling results presented here bridges the knowledge gap on the effects of syn-depositional compaction on delta morphology evolution.
Performance evaluation of bias adjustment methods for wave climate projections in the Mediterranean Sea
Authors: Lira Loarca Andrea , Besio Giovanni
Published: March 2021

Global and regional climate models are the primary tools to investigate the climate system response to different scenarios and therefore allow to make future projections of different atmospheric variables which are used as input for wave generation models to assess future wave climate. Adequate projections of future wave climate are needed in order to analyze climate change impacts and hazards in coastal areas such as flooding and erosion with waves being the predominant factor with varied temporal variability. 

Bias adjustment methods are commonly used for climate impact variables dealing with systematic errors (biases) found in global and regional climate models.  While bias correction techniques are extended in the climate and hydrological impact modeling scientific communities, there is still a lack of consensus regarding their use in sea climate variables (Parker & Hill, 2017; Lemos et al, 2020; Lira-Loarca et at, 2021)

In these work we assess the performance of different bias-adjustment methods such as the Empirical Gumbel Quantile Mapping (EGQM) method as a standard method which takes into the account the extreme values of the distribution takes, the Distribution Mapping method using Stationary Mixture Distributions (DM-stMix) allowing for a better representation of each variable in the mean regime and tails and the Distribution Mapping method using Non-Stationary Mixture Distributions (DM-nonstMix) as an improved methods which allows to take into account the temporal variability of wave climate according to different baseline periods such as monthly, seasonal, yearly and decadal. The performance of the different bias adjustment methods will be analyzed with particular interest on the futural temporal behavior of wave climate. The advantages and drawbacks of each bias adjustment method as well as their complexity will be discussed.

 

References:

Lemos, G., Menendez, M., Semedo, A., Camus, P., Hemer, M., Dobrynin, M., Miranda, P.M.A. (2020). On the need of bias correction methods for wave climate projections, Global and Planetary Change, 186, 103109.

Lira-Loarca, A., Cobos, M., Besio, G., Baquerizo, A. (2021) Projected wave climate temporal variability due to climate change. Stoch Environ Res Risk Assess.

Parker, K. & Hill, D.F. (2017) Evaluation of bias correction methods for wave modeling output, Ocean Modelling 110, 52-65
Failure to alert? Exploring perceptions of ShakeAlert during the 2019 Ridgecrest Earthquake SequenceShow affiliations
Authors: Mcbride Sara , de Groot Robert , Ruan Tao , Lv Qin , Kong Qingkai
Published: March 2021

On July 4, 2019, a M6.4 earthquake struck Ridgecrest, California. The next evening, on July 5, an even larger M7.1 rattled the region. The ShakeAlert Earthquake Early Warning System for the West Coast of the United States detected and issued ShakeAlert Messages for both earthquakes to pilot users of the system. Several ShakeAlert technical partners, including the Caltech UserDisplay demonstration console, also delivered alerts to their users. However, the Los Angeles City application (app), powered by ShakeAlert, developed and being tested by the City of Los Angeles did not deliver ShakeAlerts to approximately 700,000 test users in Los Angeles County. This is because the alerting threshold of the estimated shaking (above Modified Mercalli Intensity (MMI) IV, potentially damaging shaking) was not met for either event in Los Angeles County. While the minimum magnitude threshold of M5.0 for both earthquakes was met, the shaking estimated by the ShakeAlert system indicated that no part of Los Angeles County would experience levels of shaking that would be damaging. Although the ShakeAlert System performed as designed—in both the Ridgecrest area as well as in Los Angeles—various media outlets and initial feedback from LA City app users suggest that the public perceived that the system did not work.

This presentation offers an analysis of media and social media data related to the perceived performance of the ShakeAlert System during the Ridgecrest earthquake sequence. Specially, we focus on a comparison between media depictions and social media activity in the two geographic regions that did and did not receive a ShakeAlert message, Kern County and Los Angeles, respectively. This represents in many ways a natural experiment, and it is important to learn from these early perceptions of this emergent system.
How do recent depositional processes changes in high altitude Pyrenean lakes compare with Late Holocene variability? The case of Montmalús Lake (Principality of Andorra, Eastern Pyrenees)
Authors: Galofré Marcel-Saïd , Barreiro Fernando , Santamaría Iván , Copons Ramón , Komack Benjamin , Valero Blas.L
Published: March 2021

High mountain lakes are pristine ecosystems that archive in their sediments high-resolution records of watershed and lake evolution. Understanding how they have responded to Holocene climate fluctuations and anthropic impacts provides essential information to put into a historical context the magnitude and unique features of the current global change.

The REPLIM project funded by the Interreg program (POCTEFA 2014-2020) has implemented a network of lakes in Spain, France and Andorra to study current and past climate, environmental and anthropic changes in lakes. In August 2017, eight short sediment cores were recovered in Montmalús Lake (2433 m a.s.l., Andorra). We present a paleolimnological reconstruction based on sedimentary facies, chemical (main and trace element) analyses and δ13C and δ15N of bulk organic matter. We developed a robust age model based on 210Pb, 137Cs and 14C dating for the last 2000 years. Moreover, modern lake dynamics have been characterized with continuous water temperature measurements at various depths, periodical water sampling and sediment traps.

The results show large depositional fluctuations in the lake dynamics, especially during the Little Ice Age, with changes in organic matter accumulation, bioproductivity and sources and increased sediment delivery. Sedimentological and geochemical indicators point to the onset of high human impact in the landscape around the 11th century. Also, medieval mining and metallurgic activity from 11th to 14th centuries increased Pb deposition.

The 20th century is characterized by a recovery in organic accumulation and bioproductivity rates. Heavy metal deposition also increased during the late 20th century and started to decrease in the 2010’s decade, without reaching the background values

This study provides the first data on recent changes in lakes from the Principality of Andorra. The results highlight the uniqueness of current global change impacts in alpine lakes and underline the interplay of Great Acceleration and Global Warming processes in these fragile and sensitive depositional systems.
A spectral perspective on the existence of hemispheric circulation regimes
Authors: Riboldi Jacopo , Rousi Efi , D'Andrea Fabio , Rivière Gwendal , Lott François
Published: March 2021

While the existence of regional weather regimes (e.g., over the North Atlantic) is a known result, the presence of preferred circulation patterns at the hemispheric scale is still disputed. Space-time spectral analysis can offer a different perspective to tackle this problem, as it provides a compact representation of the large-scale flow evolution. It can objectively extract the most relevant harmonics, in terms of spatial wavenumbers and temporal frequencies, that dominate the hemispheric Rossby wave pattern at a given time and is easily applicable to gridded data sets as Reanalysis or the output of general circulation models.

With the aim to highlight the existence of clusters in the spectral space, we build a data set of spectra of upper-level meridional wind over midlatitudes (35°N-75°N) in the wavenumber/phase-speed domain for the 1979-2019 Reanalysis period. A spectrum is assigned to each day being located in the center of a sliding 61-days time window. This data set contains interesting information about the stationarity and the persistence of the hemispheric Rossby wave pattern. The most persistent harmonics are the ones related to quasi-stationary or westward propagating waves, as confirmed by an analysis of the dominant harmonics during atmospheric blocking events.

Cluster analysis is performed using self-organizing maps (SOMs) on this data set. To assess its significance, the same procedure is applied to an artificially generated red noise with the same mean, variance and lag-1 covariance as the real data. This cross-check does not highlight a preferred number of circulation regimes in the spectral space. However, a subjective classification of the spectral patterns highlighted by the SOM analysis in four different groups can be attempted: 1) a ground state, with no particular deviation from climatology; 2) a state characterized by rapidly propagating, high wavenumber waves; 3) a state characterized by slowly propagating, low wavenumber waves; and 4) a state with a clear, dominant wavenumber. Spectral patterns corresponding to each of these groups are present regardless of the chosen number of SOMs.
Petrography and geochemistry of magmatic rocks from Admiralty Bay, King George Island (South Shetland Islands, Antarctica): Preliminary results
Authors: Güraslan Işıl Nur , Altunkaynak Şafak
Published: March 2021

South Shetland Islands in Western Antarctica is dominated by a widespread magmatism through Meso-Cenozoic due to the magmatic arc created by the subduction of Phoenix plate along the South Shetland trench. Within the scope of 4th Turkish Antarctic Expedition (TAE-IV) and Turkey-Poland Bilateral cooperation, field studies were conducted in Admiralty Bay (King George Island) that host various magmatic units  in order to understand the magmatic evolution beneath Meso-Cenozoic Western Antarctica.

Magmatic products consists of Paleocene-Eocene aged volcanic and subvolcanic rocks in Admiralty Bay. Volcanic rocks are represented by terrestrial lavas and pyroclastic rocks (agglomerates, tuffs and volcanic breccias) while subvolcanic rocks consist of dykes and stocks. According to the petrographic investigations, volcanic and subvolcanic rocks in the area mostly display disequilibrium textures such as sieve textures and embayments in plagioclase and pyroxenes, patchy and oscillatory zoning in different generations of plagioclases and the existence of K-Feldspar xenocrysts with reaction rims along the borders.

Geochemically, the compositions of the magmatic rocks in the study area range from dacite to basalt. Volcanic and subvolcanic rocks show similar geochemical signatures. The samples show mostly calc-alkaline affinities. There are two predominant compositional variations, felsic and intermediate-mafic. Their MgO content ranges within 0.28-1.20 wt. % for the more felsic lavas and 2.78-5.24 wt. % for intermediate-mafic lavas. Their Al2O3 contents are relatively high (14.91-24.29 wt. %). The samples are slightly enriched in large ion lithophile elements (LILE) and light rare earth elements (LREE) compared to HFSE and HREE. The samples display high Th/Yb ratios ranging from 3.78 to 0.69. Strong depletions in Nb and Ti elements are observed as typical indicators for subduction zone magmatism. Although most of the samples show similar patterns in spider diagrams, a strong discrepancy is seen in immobile elements such as Hf and Zr, resulting in positive anomalies in felsic and negative anomalies in intermediate-mafic rocks. Similarly, negative Eu anomalies observed only in the felsic rocks. Eu/Eu* ratios varies within 0.59-0.71 for felsic rocks, and 0.85-1.12 for intermediate-mafic rocks. These different patterns in different compositions suggest an open system differentiation for the melt evolution. Petrographic and geochemical evaluations indicate that the magma beneath Meso-Cenozoic Western Antarctica is originated from lithospheric mantle metasomatized by subduction components, and fractional crystallization/assimilation fractional crystallization contributed to the magmatic evolution.

 

 

 
Numerical experiments on sensitivity of local meteorology vs. land-cover changes in the Arctic through seamless Enviro-HIRLAM modelling
Authors: Mahura Alexander , Nuterman Roman , Baklanov Alexander , Zilitinkevich Sergej , Kulmala Markku
Published: March 2021

In the recent decade, the Arctic as a whole is subject to amplified warming and well documented changes in the Arctic ecosystems, and especially, these changes are became more and more pronounced over territories of the Russian Arctic.

In this research, to study atmosphere-land-sea surfaces interactions, and in particular, heat-moisture exchange/ regime between these surfaces and for better understanding and forecasting of local meteorology in the Arctic, the seamless modelling approach was tested and applied. The Enviro-HIRLAM (Environment HIgh Resolution Limited Area Model) is an online integrated meteorology – atmospheric composition multi-scales and -processes modeling system. This model was adapted for a region of interest located in the Russian Arctic covering the inland, seashore and adjacent seas territories with the Yamal Peninsula in the center of the domain. Two short-term periods during summer (in July) and winter (in January) were chosen.

The performed model runs include changes in vegetation and land-cover as well as taking into account direct  and indirect aerosol effects (for summer), which is needed to estimate interactions and feedbacks between meteorology – atmospheric composition – land cover changes. In this study, the model was run in a downscaling chain with 5 and 1+ km horizontal resolutions. The meteorological and aerosols/ gases initial and boundary conditions required were extracted from ECMWF. The model output includes both 3D meteorology and atmospheric composition (with focus on aerosols in this study) in the surface, boundary layer and free troposphere.

The analysis of variabilities on a diurnal cycle (for key selected meteorological parameters such as air temperature, relative humidity, wind characteristics, boundary layer height, latent and sensible heat fluxes) due to changes in vegetation and land-cover was performed for selected warm and cold periods and will be presented.
The influence of a supraglacial debris cover on the mass balance and dynamics of the Djankuat Glacier, Caucasus, Russian Federation
Authors: Verhaegen Yoni , Rybak Oleg , Popovnin Victor V. , Huybrechts Philippe
Published: March 2021

We have modelled the influence of a supraglacial debris cover on the behavior of the Djankuat Glacier, a northwest-facing and partly debris-covered temperate valley glacier near the border of the Russian Federation and Georgia, which has been selected as a ‘reference glacier’ for the Caucasus region by the WGMS. A calibrated 1D coupled ice flow-mass balance-supraglacial debris cover model is used to assess the impact of the melt-altering effect of various supraglacial debris profiles on the overall steady state characteristics of the glacier. Additional experiments are also carried out to simulate the behavior of this specific debris-covered glacier in a warming future climate. The main results show that, when compared to its clean-ice version, the debris-covered version of the Djankuat Glacier exhibits longer but thinner ablation zones, accompanied by lower ice flow velocities, lower runoff production, as well as a dampening of the mass balance-elevation profile near the terminus. Experiments for warming climatic conditions primarily point out towards a significant delay of glacier retreat, as the dominant process for ice mass loss encompasses thinning out of the ablation zone. The above-mentioned effects are modelled to be increasingly pronounced with an increasing thickness and extent of the superimposed supraglacial debris cover.
A win-win situation for telecom operators and hydrologists: A proof of concept of providing probabilistic attenuation nowcasting for the telecommunication networks
Authors: Pudashine Jayaram , Velasco-Forero Carlos , Curtis Mark , Guyot Adrien , R.N. Pauwels Valentijn , P. Walker Jeffrey , Seed Alan
Published: March 2021

A novel proposal to create probabilistic attenuation nowcasting as a by-product from ensembles of rainfall forecasts is presented in this study. These attenuation nowcasts may eventually be used by mobile network operators to dynamically adjust their wireless network operations in advance and during heavy and extreme rainfall events. It may also facilitate mobile network operators to see a direct benefit of widely sharing its received power level data of their backhaul towers for 'opportunistic' rainfall estimation in real-time in urban areas becoming a clear win-win situation for telecom operators and hydrologists. It is proposed here that probabilistic attenuation forecasts can be derived from the ensembles of high-resolution forecast rainfall fields with lead times of 15 to 90 minutes generated from weather radar using the Short-Term Ensemble Prediction System (STEPS). The ensembles of rainfall predictions can be easily converted to attenuation for specific operating frequencies. This study used 109 microwave links ranging from 15 to 40 GHz to verify the results of this probabilistic attenuation forecast. Results suggest that the STEPS-based attenuation forecast was within the narrow span of the 90 percent confidence region for all microwave links tested, with up to 30-minute lead time, and was found to be skilful for lead times of up to 30-45 minutes. 
Ice-mass changes in Aurora basin, East Antarctica, in coupled and uncoupled ice-ocean simulations
Authors: Haubner Konstanze , Van Achter Guillian , Pelletier Charles , Zipf Lars , Fichefet Thierry , Goosse Hugues , Pattyn Frank
Published: March 2021

Ice mass loss of Greenland and Antarctic ice sheets is a major contributor to sea level change with an expected major impact on the world's infrastructures over the next decades. Therefore, precise estimates of sea level change are needed. However, estimates of future changes in sea level are either provided by earth system models, which rarely include ice sheet models, or by standalone ice sheet models. Hence, feedbacks between ice and atmosphere-ocean are overseen. Local scale coupled models help bridging this gap by estimating how feedbacks between the different earth systems affect global sea level estimates.

Here, we present results from a coupled simulation of the ocean-sea ice model NEMO3.6-LIM3 (1/24° grid ~ less than 2 km grid spacing) and the ice sheet model BISICLES (on 0.5 - 4km spatial resolution). The coupling routine is done via python code including variable exchange, pre- and post-processing, done offline every 3 months.

Simulated ice mass changes, grounding line position and ice velocity changes of this high-resolution coupling scheme (between 1993-2014) are compared to observations and results of uncoupled simulations. We further discuss which processes might be neglectable and which are the main drivers of ice velocity acceleration and changes in sub-shelf ocean circulation.