bluuebunny/crossref_metadata_2025 huggingface dataset:
Detailed timescale of magma-chamber assembly and eruption revealed by ultra-high precision zircon U-Pb geochronology on a Permian caldera plumbing system, Sesia Magmatic System (southern Alps, Italy)
Authors: Tavazzani Lorenzo , Wotzlaw Jörn-Frederik , Economos Rita , Sinigoi Silvano , Demarchi Gabriella , Laurent Oscar , Chelle-Michou Cyril , Bachmann Olivier
Published: March 2020

In recent years, technical developments in isotope dilution thermal ionization mass spectrometry technique (ID-TIMS) have pushed the precision of single zircon U-Pb geochronology to new limits. The use of interlaboratory calibrated U-Pb tracer solutions for isotopic dilution [1] paired with using newly developed high ohmic resistors (1013Ohm) in Faraday cup amplifiers, allow the determination of single zircon dates with precision and accuracy at the 0.02 % level [2].This level of analytical precision makes the ID-TIMS technique a geochronological tool able to unravel the detailed temporal evolution of magmatic plumbing systems older than the Mesozoic Era.

In the southern Alps, a thick sliver of continental crust, tilted and exhumed during the Alpine orogeny, is exposed as a complete crustal cross-section (Ivrea crustal section). This section preserves a transcrustal magmatic system, developed in an extensional environment in ca. 4 My during the Early Permian [3]. Its upper crustal portion consists of a zoned granitic intrusion (Valle Mosso pluton) overlaid by a dominantly rhyolitic caldera-related volcanic field (Sesia Caldera).

To obtain a time-integrated view of the petrological evolution of this plumbing system, we combine a new ultra high precision ID-TIMS zircon U-Pb dataset with zircon geochemistry from samples collected in compositionally and texturally different units of the Valle Mosso pluton and Sesia Caldera. All the analyzed units are coeval within 700 ky and the overall trends in zircon trace elements (Eu*/Eu, Zr/Hf, Sm/Yb) suggest an evolution of the reservoir dominated by fractional crystallization. The data show a ca. 200 ky gap in zircon crystallization, following the injection of recharge magma that triggered the eruption of the crystal-rich rhyolite followed by caldera collapse [3]. This suggests mass addition and rejuvenation of a partly crystallized mush, which temporarily hindered zircon crystallization. On the other hand, crystal-poor rhyolites, characterized by a younger eruption age and evolved zircon composition, likely represent late stage evacuation of evolved melt lenses extracted from a mostly crystalline framework.

[1] Condon, D. J., et al., 2015, Geochim. Cosmochim. Acta, 164, 464-480.

[2] Wotzlaw, J. F., et al., 2017, J. Anal. At. Spectrom., 32, 579-586.

[3] Karakas, O., et al., 2019, Geology, 47, 1-5.
Image Inpainting for Missing Values in Observational Climate Datasets Using Partial Convolutions in a cuDNN
Authors: Kadow Christopher , Hall David , Ulbrich Uwe
Published: March 2020

Nowadays climate change research relies on climate information of the past. Historic climate records of temperature observations form global gridded datasets like HadCRUT4, which is investigated e.g. in the IPCC reports. However, record combining data-sets are sparse in the past. Even today they contain missing values. Here we show that machine learning technology can be applied to refill these missing climate values in observational datasets. We found that the technology of image inpainting using partial convolutions in a CUDA accelerated deep neural network can be trained by large Earth system model experiments from NOAA reanalysis (20CR) and the Coupled Model Intercomparison Project phase 5 (CMIP5). The derived deep neural networks are capable to independently refill added missing values of these experiments. The analysis shows a very high degree of reconstruction even in the cross-reconstruction of the trained networks on the other dataset. The network reconstruction reaches a better evaluation than other typical methods in climate science. In the end we will show the new reconstructed observational dataset HadCRUT4 and discuss further investigations.
In situ study of volcanic ash resuspension using a portable wind tunnel.
Authors: Taddeucci Jacopo , del Bello Elisabetta , Merrison Jonathan P , Rasmussen Keld R , Iversen Jens J , Scarlato Piergiorgio , Ricci Tullio , Andronico Daniele
Published: March 2020

The resuspension of volcanic ash deposits by wind is a well-known source of hazard following explosive eruptions. Besides the mail control exerted by the local wind field, ash resuspension is also influenced by: 1) atmospheric humidity; 2) features of the deposit (grain size distribution, sedimentary structures, etc.), and 3) features of the substrate (i.e. moisture, roughness). Ash resuspension is modeled using numerical simulations, which however require physical characterization and identification of the critical parameters controlling ash resuspension. Wind tunnel studies on volcanic particles are very limited and restricted to laboratory parameterizations, with in-situ effects not been parameterized. We tested field experiments of volcanic ash resuspension developing a portable wind tunnel and deploying on proximal (3 km) ash deposits from the semi-sustained activity of Sakurajima volcano (Japan) and from distal (250 km ca.) ash deposits from the 2011 Cordon Caulle eruption (Chile). The wind tunnel is calibrated with both LDA and pitot tubes measurements. The device allows generating a controlled wind profile within a 110x12x12 cm test section, which is placed directly on an untouched test bed of naturally deposited ash. Two types of experiments were performed: 1) ramp up speed experiments, where the wind speed is increased until reaching the threshold friction speed on four different substrates; 2) constant speed experiments, where three wind speed values where kept for 20 minutes using the same substrate. The threshold friction speed is measured with a hot wire anemometer, and the movement of resuspended ash is detected by means of multiple high speed and high definition digital camcorders. In-situ measured threshold friction speeds are compared to 1) in situ observed episodes of resuspension driven by local winds and 2) laboratory determination of threshold friction speed in controlled environmental conditions, and using the same ash deposited homogeneously.

 
The ice-nucleating efficacy of glacial dust from the Copper River, Alaska
Authors: Barr Sarah , Wyld Bethany , Ratcliffe Natalie , McQuaid Jim , Murray Benjamin
Published: March 2020

Ice nucleating particles (INPs) play an important role in the climate system by influencing cloud radiative properties, cloud lifetime and precipitation. An understanding of the interaction between INPs and clouds is needed in order to improve the accuracy of both climate projections and short term weather forecasts. In the high latitudes the influence of mid and low latitude sources of INPs (such as potassium feldspar from desert dust) is reduced and local sources could be important for ice nucleation. However, there is a scarcity of field observations and many dust sources which could be important sources of INPs have not been quantified. The south coast of Alaska, in particular the Copper River valley in the Valdez-Cordova region, is one such area where there are regular dust storms. These can clearly be seen from satellite imagery, which provides information on the frequency and extent of these outbreaks. In order to investigate the potential importance of the Copper River valley as a source of INPs we undertook a field campaign to collect samples in October 2019. During this campaign size segregated aerosol samples from the near surface (1.5  metre) were collected on to polycarbonate filter substrates using a multistage cascade impactor with 5 size categories in the range <0.25 μm to >2.5 μm. We collected samples during 7 dust emission events over a 10 day period. In addition, samples of dry sediment were collected from the surface. We used the University of Leeds Microlitre Nucleation by Immersed Particle Instrument (μL-NIPI) to quantify the ice nucleating ability of these samples. We also used laser diffraction particle size analysis to determine the surface area of particles to allow the subsequent calculation of ice active surface site density (ns). In addition, surface samples were separated in order to isolate the atmospherically relevant fraction (<10 μm) and used to determine the chemical composition of the dust using x-ray diffraction. This, combined with further work such as heat testing, will be used to identify what controls the ice nucleating efficacy in this dust and if there is an active biological contribution.  We will present the results from the field campaign and subsequent analysis. These results show high ice nucleating activity of the samples, comparable to glacial dust from other regions, and highlight the importance of glacial dust as a source of INPs in the high latitudes.
Denitrification potential and occurrence of reactive minerals in the fractured carbonate aquifer of the Upper Muschelkalk, SW-Germany
Authors: Rügner Hermann , Blendinger Eva , Osenbrück Karsten , Jakus Natalia , Grathwohl Peter
Published: March 2020

Fractured or karstified carbonate rocks constitute major drinking water resources all over the world. Nitrate is one of the major threads for drinking water suppliers in regions with intensive agrucultural use. Field scale observations in the Upper Muschelkalk aquifer in the area “Oberes Gäu”, SW-Germany, suggest that denitrification due to oxidation of Fe(II) or sulfide-bearing minerals might be a relevant attentuation process at least in cases of extended mean residence times (> 5-40 years).

To identify reactive minerals within the rock matrix rock samples have been taken from major facies types within the Upper Muschelkalk from outcrops, drillings and carbonate quarries. Samples have been analysed in polished thin sections using transmitted & reflected light microscopy as well as electron microscopy including energy-dispersive elemental analysis.

Reactive Fe(II) and sulfide-bearing minearls are pyrite and marcasite as well as saddle dolomites (Fe-bearing dolomites). Concentrations of these minerals depend on facies types and amount to several weight percent iron. Porosities range from very low values (<1 %) up to 25 %.

In combination with a hydrogeological characterization, these investigations allowed to delineate reactive zones within the fractured aquifer. Denitrification within these reactive zones depends on the amount and dissolution of these minerals as well as effective diffusion in the pore space.
The Global Long-term Effects of Storm Surge Damages on Human Settlements
Authors: Kunze Sven
Published: March 2020

The influence of natural conditions on human settlements are immense. While a friendly and calm environment can lead to prosperity and growth, a hostile one with frequent natural disasters can result in stagnation, collapse, and even death. Tropical cyclones, as an unpredictable and recurring disastrous events, pose a considerable threat to prosperous development of human societies. The IPCC estimates that globally around 250 million people are vulnerable to storm surge events every year. If the threat is too large, a natural adaptation strategy would seem to move away to less dangerous places. It thus can be considered puzzling that there is a positive trend of moving to coastal flooding zones in Sub-Saharan Africa, North America and Asia, and this is projected to continue in the future. Additionally, climate change may increase the local exposure to storm surge by rising sea levels and changing intensity of tropical cyclones.

Given this worrisome development, a systematic analysis of the relationship between settlement structures and tropical cyclones is called for. In this paper we analyze whether people relocate from hazardous areas impacted by tropical cyclones. Importantly, the greatest threat from a tropical cyclone is generally due to the accompanying storm surge. But, because storm surge levels are hard to model, as of date no global (economic) impact study has attempted to model or used historic storm surge data to estimate the economic impact of tropical storms. Rather most studies only focus on wind damages, while other also include rain damages. Within this paper, we are closing this gap by explicitly modeling historic storm surge data worldwide from 1850-2015 and linking this to local population settlement. 

By combining data on bathymetry, tidal cycles, weather conditions, and  pressure drop models for the tropical cyclones we are able to estimate spatial storm surge data at a resolution of 5 arc minutes. This data then allows us, in a first step, to analyze its systematic impact on historical geo-referenced population and settlement structure data at a spatial scale of 5 arc minutes. We are able to show some interesting population patterns in response to tropical cyclones. Contrary to many empirical studies, we find that people do settle away from hazardous areas. This effect is especially large for low elevation coastal zones, while for non low elevation coastal areas we find no effect. The same pattern can be found for developing and developed countries, but the shrinking of the population is 39 percent larger in developing countries. 
A thousand pictures say a million words: digitisation and quantitative characterisation of structurally complex glaciogenic rocks
Authors: Kettler Christoph , Le Heron Daniel , Dietrich Pierre , Griffis Neil P. , Montañez Isabel P.
Published: March 2020

Gathering statistically useful, quantitative structural data is always time intensive and laborious, and thus complete digital capture of an outcrop is ideal for the modern geologist. For instance, taking several hundreds of clast fabric measurements is tedious and time consuming, especially if material is lithified. For the “time poor geologist” under constant pressure, a solution is to digitize the entire outcrop and surfaces via ground based (hand held camera) or aerial surveying (Unmanned Aerial Vehicle) methods. The acquired imagery can then be processed to produce photogrammetric 3D models. This serves as the basis for both sedimentological and structural work, including bedding geometry, in appropriate 3D modelling software.

This paper presents both the workflow and the results of the digitization of multiple Late Carboniferous outcrops in Namibia. Each of these outcrops corresponds to Late Palaeozoic Ice Age (LPIA: 360-260) deposits that have only been subject to basic description, which exhibit varying degrees of structural complexity, and whose precise relationship to LPIA ice sheets across Gondwana remains unclear. A number of 3D models are presented, which provide vital new insights into the directions of ice movement. Some of this insight comes from diamictites deposited beneath the ancient ice sheets. This is because: (i) clasts tend to align themselves in a stress-field in the active layer below the ice, (ii) striated pavements can be seen as analogous to fault surfaces and (iii) diamictites may show evidence for complex internal shear planes. We measured the orientation of those clasts directly in the 3D models from several locations to acquire a precise understanding of ice flow over a wide (hundreds of km) area, which will serve as the basis for an ice sheet reconstruction. Integrating additional morphological data from numerous drone surveys, e.g. roches moutonnées, U-shaped valleys, striated pavements permits fresh insights into the ancient glacial environment. Thus, the digital outcrop approach underpins a truly interdisciplinary (structural, sedimentological, geomorphological) approach to unravelling the LPIA record.
Quantification of long-term and time-integrated glaciation patterns in Central Asia
Authors: Blomdin Robin , Stroeven Arjen P , Harbor Jonathan M , Hättestrand Clas , Heyman Jakob , Gribenski Natacha
Published: March 2020

We use a domain-wide geomorphometric analysis to investigate spatial patterns of glacial landforms. We focus or analysis on glacial depositional landforms (e.g. marginal moraines), as well as larger erosional landforms (e.g. glacial valleys), because our aim is to quantify long-term and time-integrated glaciation patterns. Our area of interest includes two large orogens in Central Asia; the Tian Shan and Altai mountains, both located in the continental interior of Central Asia. Our analysis is crucial as it can reveal the importance of 1) topographic barriers, 2) precipitation gradients and 3) rain-shadow effects on former glaciation patterns. We focus our analysis on six different physiographic regions (n=6), defined by major drainage divides, as well as for formerly glaciated catchments (n=21)—selected because they are intersected by cosmogenic-nuclide glacial-chronological datasets. We mine published datasets on the distribution of glaciers and glacial landforms, and use these datasets, together with freely available digital elevation models, to extract landform-specific hypsometric (area—elevation) distributions. Hypsometric peaks for modern glaciers (i.e. median glacier elevations) show pronounced spatial gradients; increasing elevations from the northern to the southern Tian Shan, and increasing median elevations from the northern to both the southeastern and southwestern Altai Mountains. This is interpreted to reflect topographic barrier effects and decreasing modern precipitation rates (i.e. increasing continentality), as a result of a weakening of the Mid-latitude Westerlies, across the main axes of the two mountain systems. A similar pattern can be observed in the paleorecord; reconstructed long-term and time-integrated glaciation patterns, also show pronounced spatial gradients, equivalent to modern median glacier elevation patterns. This observation indicates that during former periods of glaciation, maximum paleoglacier extents—reconstructed by delineating the extent of glacial depositional and erosional landforms (formed over one-to-several glacial cycles, over >100 thousand years)—were correspondingly controlled by a westerly-sourced moisture supply, and was thus affected by precipitation patterns similar to those of today.
Mechanisms of continental break-up : tectonic, stratigraphic and structural constraints from a preserved distal rifted margin (Agly massif, eastern Pyrenees)
Authors: Motus Martin , Denèle Yoann , Mouthereau Frédéric , Nardin Élise
Published: March 2020

The Agly massif and its neighboring Mesozoic basins altogether form part of the Pyrenean Cretaceous rift preserved in the retro-wedge of the Pyrenean mountain belt. The relationships between the tectonic evolution of these syn-rift basins and the crustal-scale tectonic processes allows us to investigate the strain partitioning, the rheology and the sequence of deformation associated with the thinning of the deep crust leading to continental break-up.

Based on structural, microstructural and thermochronological studies of the deep crust of the Agly massif and the revised stratigraphy and depositional environments of the pre- and syn-rift sedimentary rocks, we propose a tectonic reconstruction of the eastern segment of the Pyrenean rift at the time of continental break-up. Two parallel cross sections allow us to discuss about the mechanical behavior of the deep crust and the control by lateral rheological heterogeneities on the spatial and temporal evolution of rifting. We emphasize the role of low-angle (decollement) and high-angle (detachment) extensional structures in the deep crust that collectively accommodate thinning and exhumation, respectively. Structural relationships between the Variscan basement and the Mesozoic basins are highlighted, such as a major extensional detachment fault system exhuming the mantle at the contact between the Agly massif and the Boucheville basin in the south. We further discuss the origin of tectono-sedimentary breccias in the context of crustal-scale thinning/exhumation processes and basins evolution.

Our different results are finally integrated in a 3D tectonic model of the distal margin, illustrating a crustal scale space-time vision of the mechanisms leading to continental break-up.
Modeling of climate change impact on hydrological regime in small headwater mountainous catchments in Slovakia
Authors: Hlavcova Kamila , Kubán Martin , Sleziak Patrik , Szolgay Jan
Published: March 2020

Assessment of the impacts of climate change on hydrological regime is important for sustainable water resources management. The objective of this study is to assess the impacts of future climate changes on the hydrological regime of the headwater catchment of the Vistucky Creek (area 9.8 km2) in south-western Slovakia. Changes in climatic characteristics (i.e. precipitation and air temperature) for periods 2022-2060 and 2062-2100 were prepared by two regional climate models KNMI and MPI using the A1B emission scenario (average related to fossil carbon production). Both climatic scenarios assume increase in the air temperature and precipitation (higher in winter than in summer). A lumped conceptual rainfall-runoff model (the HBV-based TUW model) was used to simulate the catchment hydrological behaviour. The TUW model was calibrated for the reference period of 1982 – 2008. The calibration of the model was performed 50 times with a differential evolution algorithm. After obtaining the collection of the 50 parameter sets, the best set (in terms of Nash-Sutcliffe efficiency and the volume error) was chosen. This set of model parameters was used for the simulation of long-term mean monthly runoff for the three periods (i.e. 1982-2008, 2022-2060, and 2062-2100). The results show that changes in the long-term runoff seasonality and extremality of hydrological cycle could be expected in the future if the climate changes as the scenarios assume. The runoff should increase in autumn and winter months (i.e. from September to February) and decrease in spring and summer months (i.e, from April to August) compared to the reference period. Peakflows should increase in period 2062-2100 while discharge minima should slightly decrease (only for the climatic data from the KNMI model). It indicates possible increase in flow extremality. Catchment water storage as expressed by the soil moisture index and baseflow should decrease in period 2062-2100, especially according to climatic data from the KNMI model. Our contribution will discuss these changes in hydrological regime in the climate change context.
Describing macrofaunal impact on nutrient flux – what is the potential of trait based approaches?
Authors: Wrede Alexa , Andresen Henrike , Asmus Ragnhild , Wiltshire Karen Helen , Brey Thomas
Published: March 2020

Ever-expanding human activities on land and at sea have amplified the need for easily applicable proxies to effectively predict human mediated changes in ecosystem functioning and biogeochemical cycling. Here we investigate the ability of different proxies to predict macrofaunal impact on nutrient fluxes of ammonium, nitrate, nitrite, silicate and phosphate under different environmental conditions. As proxies we chose simple community descriptors (i.e. density, wet biomass, ash free dry mass) as well as two trait-based indices that were created to describe macrofauna-sediment interactions (i.e. community bioturbation potential (BPc) and community irrigation potential (IPc)). We hypothesize that trait based indices, will increase the predictability of macrofaunal impact on nutrient fluxes compared the more simple community descriptors. We correlate all proxies with experimental nutrient flux data measured under different environmental conditions using generalized linear models. Generally environmental conditions significantly affected all analysed nutrient fluxes and mostly provided better predictions than any of the proxies for macrofaunal impact by itself. Yet a combination of the proxies and the environmental conditions always increased prediction accuracy. Hereby the irrigation trait based indices enhanced the predictability of the nutrient fluxes of ammonium, nitrate, nitrite, silicate and phosphate most.
The International DORIS Service is preparing the future
Authors: Ferrage Pascale , Soudarin Laurent , Lemoine Frank
Published: March 2020

The DORIS system recorded its first measurement on February 3rd, 1990, from the SPOT-2 remote sensing satellite. 30 years after, the system is at its best. DORIS has proven greatly valuable for geodesy and geophysics applications: measuring tectonic plate motions, determination of the rotation and the gravity parameters of the Earth, contributing to the international reference system. Technological and methodological improvements have allowed the improvement in the estimates of the positions of the DORIS tracking ground stations, the Earth rotation parameters and other geodetic variables such as the geocenter and the scale of the ITRF.
The International DORIS Service (IDS) was created in 2003 under the umbrella of the International Association of Geodesy (IAG) to foster scientific research related to the French DORIS tracking system and to deliver scientific products, mostly related to the International Earth rotation and Reference systems Service (IERS). Since its start, the organization has continuously evolved, leading to additional and improved operational products from an expanded set of DORIS Analysis Centers. IDS is now based on a reinforced structure with two Data Centers, six Analysis Centers, four Associate Analysis Centers, and a Combination Center. Using the experience gained in the preparation of the ITRFs, many improvements were made all along both in data analysis and on technical aspects. After the IDS Retreat held in June 2018, the IDS GB worked on the development of a strategic plan for the IDS. In the coming years, IDS will focus on growing the community, extending the DORIS applications, and improving the technology, the infrastructure and the processing.
This presentation addresses the recent achievements made by IDS and how the service is preparing the future.
The Flood Resilience Dashboard
Authors: McCallum Ian , Velev Stefan , Laurien Finn , Mechler Reinhard , Keating Adriana , Hochrainer-Stigler Stefan , Szoenyi Michael
Published: March 2020

The purpose of the “Flood Resilience Dashboard” is to put geo-spatial flood resilience data into the hands of practitioners. The idea is to provide an intuitive platform that combines as much open, peer-reviewed flood resilience related spatial data as possible with available related spatial data from the Flood Resilience Alliance, which in turn can be used to inform decisions. This data will include among others the Zurich Flood Resilience Measurement for Communities (FRMC) data, Vulnerability Capacity Assessment (VCA) maps, remote sensing derived information on flooding and other biophysical datasets (e.g. forest cover, water extent), modelled risk information, satellite imagery (e.g. night-time lights), crowdsourced data and more. 

The Dashboard will, as much as possible, lower the entry barrier for non-technical users, providing a simple login experience for the users. Users should be able to explore the Dashboard using standard web map navigation tools. The various charts and tables on the Dashboard dynamically refresh as features on the map are selected or the map extent is changed. No previous experience or understanding of geo-spatial data is required, beyond basic web-map navigation.
When 1D response analysis fails: application of Earthquake HVSR in Site-Specific Amplification Estimation
Authors: Zhu Chuanbin , Pilz Marco , Cotton Fabrice
Published: March 2020

Ground response analyses (GRA) model the vertical propagation of SH waves through flat-layered media (1DSH) and are widely carried out to evaluate local site effects in practice. Horizontal-to-vertical spectral ratio (HVSR) technique is a cost-effective approach to extract certain site-specific information, e.g., site resonant frequency, but HVSR values cannot be directly used to approximate the level of S-wave amplification. Motivated by the work of Kawase et al. (2019), we propose a procedure to correct earthquake HVSR amplitude for direct amplification estimation. The empirical correction, in essence, compensates HVSR by generic vertical amplifications grouped by vertical fundamental resonant frequency (f0v) and 30 m average shear-wave velocity (VS30) via k-mean clustering. In this investigation, we evaluate the effectiveness of the corrected HVSR in approximating observed amplification in comparison with 1DSH modelling. To the end, we select a total of 90 KiK-net surface-downhole recording sites which are found to have no velocity contrasts below downhole sensor and thus of which surface-to-borehole spectral ratio (SBSR) can be taken as its empirical transfer function (ETF). 1DSH-based theoretical transfer function (TFF) is computed in the linear domain considering the uncertainty in VS profile through randomization. Five goodness-of-fit metrics are adopted to gauge the closeness between observed (ETF) and predicted (i.e., TTF and corrected HVSR) amplifications in both amplitude and spectral shape. The major finding of this study is that the empirical correction procedure to HVSR is highly effective, and the corrected HVSR has a “good match” in both spectral shape (Pearson’s r > 0.6) and amplitude (Index of agreement d > 0.6) at 74% of the investigated sites, as opposed to 17% for 1DSH modelling. In addition, the HVSR-based empirical correction does not need a site model and thus has great potentials in site-specific seismic hazard assessments.
era5cli: The command line tool to download ERA5 data
Authors: Camphuijsen Jaro , van Haren Ronald , Dzigan Yifat , Drost Niels , Alidoost Fakhareh , Andela Bouwe , Aerts Jerom , van Weel Berend , Hut Rolf , Kalverla Peter
Published: March 2020

With the release of the ERA5 dataset, worldwide high resolution reanalysis data became available with open access for public use. The Copernicus CDS (Climate Data Store) offers two options for accessing the data: a web interface and a Python API. Consequently, automated downloading of the data requires advanced knowledge of Python and a lot of work. To make this process easier, we developed era5cli. 

The command line interface tool era5cli enables automated downloading of ERA5 using a single command. All variables and options available in the CDS web form are now available for download in an efficient way. Both the monthly and hourly dataset are supported. Besides automation, era5cli adds several useful functionalities to the download pipeline.

One of the key options in era5cli is to spread one download command over multiple CDS requests, resulting in higher download speeds. Files can be saved in both GRIB and NETCDF format with automatic, yet customizable file names. The `info` command lists correct names of the available variables and pressure levels for 3D variables. For debugging purposes and testing the `--dryrun` option can be selected to return only the CDS request. An overview of all available options, including instructions on how to configure your CDS account, is available in our documentation. Source code is available on https://github.com/eWaterCycle/era5cli.

In this PICO presentation we will provide an overview of era5cli, as well as a short introduction on how to use era5cli.
A Climate Model Structural Behavior Under Different Forcing
Authors: Russo Emmanuele , Fallah Bijan , Raible Christoph
Published: March 2020

In this study the COSMO-CLM sensitivity to parameters perturbation is investigated under different climate forcings. The main aim is to understand

how the uncertainty of the model propagates in different climate regimes and whether the model presents structural stability when different forcings are considered. For this purpose, two Physically Perturbed Ensembles (PPEs) are produced, each composed of 35 realizations, at two different periods of the past: the Mid-Holocene, 6000 years ago, and the Pre-industrial period. The two periods present significant differences in the seasonal values of incoming insolation due to changes in the Earth’s orbital configuration. The effects of these changes on the Earth’s radiative balance, at least when considering seasonal values, are of the same magnitude of the changes due to GHGs emissions of the worst case Representative Concentration Pathway scenario (RCP8.5). Two additional ensembles, but with a lower number of components, are produced in order to determine the role of the boundaries with respect to the one of changes in the climate forcings.

Preliminary analyses show that the model presents a structurally stable behavior in the two periods for several variables, in particular when considering climate mean statistics. Some parameters do not produce sensible changes in the model behavior in both periods. This confirms that conducting a calibration of the model only on a restricted set of parameters is a good praxis when willing to simulate future or past climate change. On the other hand, some parameters show remarkable changes with respect to a reference simulation: these differences are maintained in the two different regimes, pointing again to a relatively good model stability, but also to a very similar sensitivity of the model to the different forcings. Finally, when considering the ensembles with the same forcings but different boundaries, the effect of the boundaries seems to play a major role. This is particularly important for climate projections using the COSMO-CLM: a model PPE would probably not be particularly relevant in order to characterize the model uncertainty, but more attention should instead be paid to consider a wide ensemble of independent boundary realizations with different GCMs
Convection of Electrically Conducting Fluid in a Rotating Magnetic System: Cross rolls
Authors: Rameshwar Yadagiri , Srinivas Gudukuntla , Rani Hari Ponnamma , Brestensky Jozef , Filippi Enrico
Published: March 2020

We have studied theoretically the weakly nonlinear analysis in a rotating Rayleigh-Benard system of electrically conducting fluid in the presence of applied horizontal magnetic field with free-free boundary conditions [1]. This theoretical approach is carried near the onset of convection to study the flow behavior at the occurrence of cross rolls, which are perpendicular to the applied magnetic field. The nonlinear problem is solved by using the Fourier analysis of perturbations up to the O(ε8) to study the cross rolls visualization [2,3]. The dependence of the Nusselt number on the Rayleigh number, Ekman number, Elsasser number is extensively examined. The fluid flow is visualized in terms of kinetic energy, potential energy, streamlines, isotherms, and heatlines.

 

References :

[1] P. H. Roberts and C. A. Jones , The Onset of Magnetoconvection at Large Prandtl Number in a Rotating Layer I. Finite Magnetic Diffusion, Geophysical and Astrophysical Fluid Dynamics, Vol. 92, pp. 289-325 (2000).

[2] H.L. Kuo, Solution of the non-linear equations of the cellular convection and heat transport,  Journal of Fluid Mechanics,  Vol.10, pp.611-630 (1961).

[3] Y. Rameshwar, M. A. Rawoof Sayeed, H. P. Rani, D. Laroze, Finite amplitude cellular convection under the influence of a vertical magnetic field, International Journal of Heat and Mass Transfer, Vol. 114, pp.  559-577 (2017).
Variation in canopy energy exchange characteristics across an ecosystem mosaic in the dry Mediterranean region
Authors: Amer Madi , Stern Rafael , Rotenberg Eyal , Yakir Dan
Published: March 2020

Assessment of the plant-climatic interactions in the land biosphere requires a combined perspective of both the biogeochemical effects (BGC; such as the carbon sink), and the biogeophysical effects (BGP; such as the vegetation albedo and radiative balance), which can often have contrasting consequences for ecosystem functioning and climate. Aiming to increase our knowledge on semi-arid ecosystems that are insufficiently represented in global studies, we examine the variations in key BGP features among different vegetation types in a dry Mediterranean region in southern Israel.

The study included planted pine forest (pinus halepensis), natural broad-leaf oak maquis (Quercus calliprinos), wheat field and a managed grassland, located in close proximity (within 2 km) under the same climatic conditions (mean annual temperature = 20.8C, annual mean precipitation, P= 403 mm, aridity index = 0.4). Using a state-of-the-art mobile laboratory, we carried out measurement campaigns of eddy covariance fluxes of CO2, sensible, H, and latent, LE, heat fluxes, and the radiation balance (incoming and outgoing short- and long-wave radiations) between the ecosystems and the atmosphere in different seasons during 2016-2018.

The results showed significant differences in net radiation and in albedo among the ecosystem, with net radiation values of ~666, ~582, ~443 and 456 W m-2 and albedo values of ~0.13, ~0.16, ~0.19 and ~0.20 for pines, maquis, wheat and grassland, respectively. The lowest albedo of the pine stand was associated with the largest H (a ‘convector effect’) of ~583 W m-2 compared to ~313, ~198 and ~176 W m-2 in the maquis, wheat and grassland ecosystems (midday means of peak activity season). The pine stand was also more adjusted to stress conditions than the oak maquis ecosystem through ‘avoidance’ of high activities during extreme conditions of heat and drought (reducing canopy conductance and associated fluxes). It is likely that the observed differences between the pine and oak maquis stand help explain the greater expansion of pine stands into the semi-arid regions, even to areas with mean annual P of 290 mm (aridity index = 0.2) where oak maquis cannot be found.
Ring current decay during storm recover phase: RBSP Observation
Authors: Chen Ao , Yue Chao , Chen Hongfei , Zong Qiugang
Published: March 2020

Ring curent is an important current system in the Earth's magnetosphere. Many charged particles, especially protons and oxygen ions, move around the Earth due to due to electromagnetic drifts, which forms the ring current. During the main phase of a magnetic storm, ring current will grow stronger while it will decay slowly during recover phase. It is thought that charge exchange is the main mechanism of ring current decay [Daglis et al., 1999]. Hereby we use charge exchange theories to calculate charge exchange lifetimes of protons and oxygen ions during recover phase of many storms. Meanwhile, data of RBSP has been used for fitting in order to get real lifetimes of  protons and oxygen ions. We compared the observed lifetimes with the theory prediction and find that  a. the two are close at high L(>4) values and low energy(<55keV) for protons, b. the two are similar in a wide energy(1~600keV) range but a relatively narrow L(different at different energies) range, c. day or night make little difference on the comparison results.
How to scale root water uptake from root scale to stands and beyond – a theoretical framework, practical lessons, and next steps
Authors: Bouda Martin , Vanderborght Jan , Couvreur Valentin , Meunier Félicien , Javaux Mathieu
Published: March 2020

Estimating plant uptake of soil water has been a persistent problem in process-based earth system models (ESMs). Initially ignored altogether, plant access to soil water was long modelled with heuristic approaches at large scales. These formulations are currently being replaced as ESMs begin to incorporate more detailed plant hydraulics schemes based on the soil-plant-atmosphere continuum concept. While the new schemes greatly improve mechanistic description of above-ground plant hydraulics, they have given rise to various issues belowground, from excessive hydraulic redistribution to numerical instability. As detailed 3D descriptions of root systems and water flow equations on the soil-root domain have been established, the key challenge is how to scale them up to relevant scales, reducing computational cost to a trivial level without loss of accuracy.

Here, we set out a mathematical framework that incorporates recent advances in this area and allows us to relate them to each other. Comparing and contrasting different models, formulated in a novel matrix form of the water flow problem in the root system, allows us to make inferences about their suitability for use in upscaling. We are able to show how to avoid discretization error in the upscaled root scheme, as well as which upscaling method offers full generality, and which yields the computationally simplest forms. These theoretical results are fully supported by numerical simulations of fully explicit 3D root systems and their upscaled versions. Improved performance of the upscaled models is also demonstrated in an application to field data from the Wind River Crane flux tower site (reduced model bias, root mean squared error, and increased robustness of fitted parameters).

Root water uptake equations can now be scaled up without discretization error for arbitrary root systems. The chief remaining source of error is soil moisture heterogeneity within discretized soil elements where it is assumed uniform by any given model (e.g. within each vertical layer). The main task for future work thus becomes to achieve a correspondingly accurate description for soil moisture heterogeneity. Some of the upscaling approaches compared here offer hints at potential next steps in this direction.
Assessment of variation of baseflow contribution to stream flow in a hard-rock aquifer
Authors: Nara Siva Naga Venkat , Muddu Sekhar , Ghosh Prosenjit
Published: March 2020

Stream flow is combination of two major portion of flows as direct runoff and baseflow. Study of baseflow and direct runoff is much needed to understand the hydrology of a watershed, including surface and sub-surface water interaction, and to assess the ecological functioning of streams. Tropical countries like India facing major challenges in water management; especially for irrigation and drinking water. In such regions identification of baseflow sources, knowledge of baseflow availability and analysis of their varied contribution to the stream is needful. Baseflow plays a critical role in maintaining streamflow, especially during pre and post monsoon periods.

Recursive digital filter technique is adopted for the daily stream flow data measured at river gauge stations on Kabini stream of Cauvery basin, to separate baseflow component from stream flow hydrograph. In terms of hydrogeology, since Cauvery basin occupied with hard-rock terrain, it is important to investigate the intra annual variation of groundwater discharge into the stream. In the present study an attempt has been made by considering daily stream flow data at two river gauge observation points, and annual baseflow and baseflow index is calculated through RDF method. The results obtained from RDF method are validated with the help of hydrogeochemical tracers by applying End Member Mixing Analysis (EMMA) to the hydrogeochemical data for the period of 2018-19 hydrological cycle.
Vertical distribution of Kolmogorov Constants of Atmospheric Turbulence over an Urban Surface
Authors: Ding Weichen , Shi Yu , Zhang Zhe , Hu Fei
Published: March 2020

The Kolmogorov constant is fundamental in stochastic models of turbulence, and significant in boundary layer meteorology especially. Though lots of experiments have been conducted to study Kolmogorov Constant, constant at high elevation and over urban surface was rarely researched. Therefore, in this paper, ultrasonic data at seven levels over an urban underlying surface were used to calculate the Kolmogorov constants of velocity. The results of Kolmogorov constants at the different floors indicated that the constants below 47m were smaller because of the influence of the urban canopy layer. Besides, the time-varying result showed that constants were universally independent of stability. Furthermore, Kolmogorov constant in this paper was close to the result determined by former experiments.
Sedimentological features and thermal maturity signature of the upper Triassic Streppenosa and Noto Formations, source rocks in the Hyblean Plateau (SE Sicily, Italy)
Authors: Maniscalco Rosanna , Corrado Sveva , Balestra Martina , Schito Andrea , Casciano Claudio Ivan , Forzese Martina , Montalbano Sergio , Pellegrino Alessandra , Bachtiar Andang , Palmeri Giuseppe , Di Stefano Agata
Published: March 2020

The upper Triassic Streppenosa and Noto Formations are considered the main source rocks of the Hyblean Plateau in south-eastern Sicily, that represents the present-day deformed foreland of the Sicilian fold-and-thrust belt. This work focusses on the Upper Triassic Streppenosa and Noto Formations, penetrated by the Eureka 1 onshore well (south-eastern Sicily, Italy) in order to constrain the burial-thermal history of this basin of the western Tethys. According to previous paleogeographic reconstructions, starting from Norian, the palaeogeographic scenario consisted, moving from north to south, of a wide carbonate platform (Sciacca Fm.), adjacent to two different domains: the euxinic lagoon/basin of the Noto Formation, and, to the south, the basin of the Streppenosa Formation. Eureka 1 well is located in the inner portion of the platform-basin system and its Triassic succession consists of alternation of black shales and micritic, microbial dolomitic laminated limestones. A detailed description of the sedimentological facies from cores samples has been performed together with detailed organic petrography/Raman spectroscopy and clay mineralogy on fine grained sediments to assess thermal maturity of the Streppenosa and Noto Fms. The main facies consist of light-grey limestones (wackestone-mudstone) with scattered sub-angular intraclast, light grey finely laminated limestones, dark grey-black laminated mudstones, brownish undulated algal laminae saturated with bitumen. The cores are often bitumen saturated and interrupted by different sets of open microfractures, veins filled with calcite, and stylolites (parallel and vertical with respect to lamination) that may enhance and/or inhibit at places the fluid flow. Concerning thermal maturity, the studied interval falls in the lower-mid portion of the oil window, with robust agreement among the geothermometers derived from the three adopted techniques.
Tracing marker horizons in the Serifos Island metamorphic core complex (Cyclades, Greece)
Authors: Soukis Konstantinos , Andropoulou Katerina , Grasemann Bernhard , Antoniou Varvara , Lozios Stelios
Published: March 2020

Mapping metamorphic rocks in areas with complex tectonometamoprhic history and multi-phase syn-metamorphic isoclinal folding, usually means not having safe stratigraphic evidence such as biomarkers or marker layers to make correlations between formations and units or to assign ages. Novel analytical techniques can be very useful but raise the cost and they do depend on meticulous field work. Therefore, traditional methods such as detailed geological mapping may be the only way to reach to valid correlations.

The Cycladic Islands in the Aegean domain is an area where rocks present a complex history of subduction, accretion and subsequent syn-and post-orogenic exhumation along crustal scale detachments. Fossils are very rarely preserved and lithologies are quite similar throughout the column. Serifos Island is the area where the top-to-S West Cycladic Detachment System (WCDS) was firstly identified and mapped in detail. The detachment is exposed at the northernmost (Platys Ghialos) and the southernmost (Megalo Livadi, Cape Avessalos) part of the Island, having Cycladic Blueschist Unit rocks in the footwall and Upper Unit rocks in the hanging wall. The geometry of the fault resulted from late stage doming on the island scale.

At Platys Ghialos, the structurally highest part of the WCDS footwall, a very distinct lithological sequence is observed exactly below the ultramylonitic marble of the Detachment zone. This sequence includes a marble metaconglomerate, which serves as the main index layer, blue-gray marble, schist, metaconglomerate and metabasite layers. Detailed mapping of the western part of Serifos in 1:5.000 scale, shows that this succession is traced all the way from Platys Ghialos to Megalo Livadi. Also, it revealed meso- to macroscopic scale isoclinal refolding. The overall pattern proves the footwall has a periclinal geometry which follows the doming of the detachment.