bluuebunny/crossref_metadata_2025 huggingface dataset:
Landscape analysis through pictorial transects in degraded lands.
Authors: Campos Juan Antonio , Villena Jaime , Moreno Marta M. , Peco Jesús D. , Sánchez-Ormeño Mónica , Moreno Carmen , Higueras Pablo
Published: March 2021

Understanding the dynamics of plant populations and their relationship with the characteristics of the terrain (slope, texture, etc.) and with particular phenomena (erosion, pollution, environmental constrains, etc.) that could affect them is crucial in order to manage regeneration and rehabilitation projects in degraded lands. In recent years, the emphasis has been placed on the observation and assessment of microtopographic drivers as they lead to large-scale phenomena. All the ecological variables that affect a given area are interconnected and the success in unraveling the ecological patterns of operation relies on making a good characterization of all the parameters involved.

It is especially interesting to study the natural colonization processes that take place in Mediterranean areas with a high degree of seasonality, to whose climatic restrictions, the presence of pollutants and various anthropic actions, can be added. Over these degraded areas, we propose using a new tool, what we have come to call "pictorial transects", that is, one-dimensional artificial transects built from low-scale photographs (2 m2) taken along a line of work (transect) where you can see the points where ecological resources are generated, stored and lost, and their fluctuation throughout time. A derivative of these would be the "green transects" in which the green color has been discriminated using the open software Image I. It is an inexpensive, fast and straightforward pictorial method that can be used to research and monitor the spatial and temporal fluctuation of the potential input of resources (organic matter, water, fine particles, etc.) to the ecosystem.

The information obtained from pictorial transects not only refers to the measurement of the photosynthetic potential per unit area or the location of the critical points (generate, storage or sink of resources) but also makes it possible to monitor the specific composition of the plant cover. For an appropriate use of this methodology, the criteria to determine the direction and length of the different transects must be previously and carefully established according to the objectives proposed in the study. For example: a radial transect in a salty pond will give us information on the changes in the plant cover as we move away from the center and the salinity decreases. In the same pond, a transect parallel to the shore will give us information on those changes that occur in the vegetation that do not depend on the degree of salinity. There are some cases in which this method could be very useful, as in the natural colonization of a degraded mine site or to assess the progression area affected by allochthonous species or weeds in extensive crops.
Cryogenic cave carbonate formation during the Industrial Era in the Central Pyrenees (Iberian Peninsula)
Authors: Bartolomé Miguel , Moreno Ana , Luetscher Marc , Spötl Christoph , Leunda Maria , Cazenave Gerard , Belmonte Ánchel , Osácar Cinta , Cheng Hai , Edwards Richard Lawrence , Sancho Carlos
Published: March 2021

Cryogenic cave carbonates (CCC) are rare speleothems that form when water freezes inside cave ice bodies. CCC have been used as an proxy for permafrost degradation, permafrost thickness, or subsurface ice formation. The presence of these minerals is usually attributed to warm periods of permafrost degradation. We found coarse crystalline CCC types within transparent, massive congelation ice in two Pyrenean ice caves in the Monte Perido Massif: Devaux, located on the north face at 2828 m a.s.l., and Sarrios 6, located in the south face at 2780 m a.s.l. The external mean annual air temperature (MAAT) at Devaux is ~ 0°C, while at Sarrios 6 is ~ 2.5°C. In the Monte Perdido massif discontinuous permafrost is currently present between 2750 and 2900 m a.s.l. and is more frequent above 2900 m a.s.l. in northern faces. In Devaux, air and rock temperatures, as well as the presence of hoarfrost and the absence of drip sites indicate a frozen host rock. Moreover, a river flows along the main gallery, and during winters the water freezes at the spring causing backflooding in the cave. In contrast, Sarrios 6 has several drip sites, although the gallery where CCC were collected is hydrologically inactive. This gallery opened in recent years due to ice retreat. During spring, water is present in the gallery due to the overflow of ponds forming beneath drips. CCC commonly formed as sub-millimeter-size spherulites, rhombohedrons and rafts. 230Th ages of the same CCC morphotype indicate that their formation took place at 1953±7, 1959±14, 1957±14, 1958±15, 1974±16 CE in Devaux, while in Sarrios 6 they formed at 1964±5, 1992±2, 1996±1 CE. The cumulative probability density function indicates that the most probable formation occurred 1957-1965 and 1992-1997. The instrumental temperature record at 2860 m a.s.l. indicates positive MAAT in 1964 (0.2°C) and 1997 (0.8°C). CCC formation could thus correspond with those two anomalously warm years. The massive and transparent ice would indicate a sudden ingress of water and subsequent slow freezing inside both caves during those years. Probably, CCC formation took place at a seasonal scale during the annual cycle.
Investigation of direct solar proton impact on Arctic stratospheric ozone
Authors: Jia Jia , Kero Antti , Kalakoski Niilo , E. Szeląg Monika , T. Verronen Pekka
Published: March 2021

Recent studies reported up to a 10 % average decrease of lower stratospheric ozone at ∼ 20 km altitude following solar proton events (SPEs), based on superposed epoch analysis (SEA) of ozonesonde anomalies. Our study uses 49 SPEs that occurred after the launch of Aura MLS (2004–now) and 177 SPEs that occurred in the WACCM-D (Whole Atmosphere Community Climate Model with D-region ion chemistry) simulation period (1989–2012) to evaluate Arctic polar atmospheric ozone changes following SPEs. At the mesospheric altitudes a statistically significant ozone depletion is present. At the lower stratosphere (<25 km), SEA of the satellite dataset provides no solid evidence of any average direct SPE impact on ozone. In the individual case studies, we find only one potential case (January 2005) in which the lower-stratospheric ozone level was significantly decreased after the SPE onset (in both model simulation and MLS observation data). However, similar decreases could not be identified in other SPEs of similar or larger magnitude. We find a very good overall consistency between WACCM-D simulations and MLS observations of SPE-driven ozone anomalies both on average and for the individual cases, including case in January 2005.
Tomography-based investigation of concurrent snow creep and isothermal metamorphism
Authors: Bernard Antoine , Hagenmuller Pascal , Chambon Guillaume , Montagnat Maurine
Published: March 2021

Once on the ground, the microstructure of snow, i.e. the three-dimensional arrangement of ice and pores, quickly evolves with metamorphism and deforms under the overburden of the overlaying snow. Understanding these concurrent processes is important to predict the evolution of the physical and mechanical properties of snow which are crucial for many applications, such as avalanche forecasting. To this end, we monitored oedometric creep tests of snow under isothermal conditions at -8.6°C for about one week with X-ray tomography. We investigated the evolution of recent snow under a constant load of around 4 kPa, where both ice matrix creep and metamorphism are active. Our time-series comprises one of the most highly-resolved images of snow microstructure evolution, with a temporal resolution of 3 h and spatial resolution of 8.5 microns and thousands of images. Interestingly, we observed distinct effects of the overburden and of the vapor transport on the microstructure evolution. In particular, the quantification of the ice bond network through the Euler characteristic and the min-cut surface shows that metamorphism progressively increases the bond size almost independently of the applied overburden, while the application of an overburden yields a rapid increase of the bond coordination number. These distinct impacts exhibit the difficulty to accurately reproduce the time evolution of recent snow by snow cover models, whose snow microstructure representation with density and snow type remains too coarse. 
Application of COSMO-SPECS for remote sensing observations of mixed-phase clouds during CyCare and DACAPO-PESO
Authors: Schrödner Roland , Bühl Johannes , Senf Fabian , Knoth Oswald , Stoll Jens , Simmel Martin , Tegen Ina
Published: March 2021

During the campaigns CyCyare (Limassol, Cyprus) and DACAPO-PESO (Punta Arenas, Chile), remote sensing methods were applied to study mixed-phase clouds. The two sites show contrasting aerosol loads with very clean, marine atmosphere over southern Chile and higher aerosol mass and number concentrations over Cyprus, which frequently are dust-laden. The observations suggest differing cloud properties. To further study the properties and evolution of the observed clouds as well as their relation to the ambient aerosol, the detailed coupled cloud microphysical model COSMO-SPECS is applied for selected real case studies.

The SPECtral bin cloud microphysicS model SPECS was developed to simulate cloud processes using fixed-bin size distributions of aerosol particles and of liquid and frozen hydrometeors. It was implemented in the numerical weather prediction model COSMO. COSMO-SPECS has been used for idealized case studies with horizontally periodic boundary conditions. Recently, the model system has been enhanced by considering lateral boundary conditions for the hydrometeor spectra allowing for high-resolution real case studies on nested domains. The simulations are carried out by first applying the meteorological driver COSMO using its standard two-moment microphysics scheme on multiple nests with increasing horizontal resolution. Finally, the COSMO-SPECS model system is applied on the innermost domain with a horizontal resolution of a few hundred meters using boundary data derived from the finest driving COSMO domain. For this purpose, the bulk hydrometeor fields of the driving model need to be translated into the corresponding hydrometeor mass and number distributions of SPECS’ hydrometeor spectra.

In this work, we present first results for selected case-studies of mixed-phase clouds observed during CyCyare and DACAPO-PESO. The results of the model simulations are compared against the LIDAR and cloud radar observations at the two sites.
Grain boundary character information via individual imaging or statistical analyses: complexion transitions and grain boundary segregation
Authors: Marquardt Katharina , Dobson David , Hunt Simon , Faul Ulrich
Published: March 2021

Grain boundaries affect bulk properties of polycrystalline materials, such as electrical conductivity, melting or bulk viscosity. In the past two decades, observations of marked bulk material property changes have been associated with changes in the structure and composition of grain boundaries. This led to the term “grain boundary complexions” to mark the phase-like behaviour of grain boundaries while differing from phases in the sense of Gibbs (Cantwell 2014).

Here we introduce the principles of grain boundary structure to property relations and potent methods to study these. The focus is on the combination of structural, chemical and statistical analysis as obtainable using transmission electron microscopy and electron backscatter diffraction. Data from these complementary methods will be discussed on two systems; garnet and olivine polycrystals.

Past elasticity measurements showed that the Youngs modulus of garnet polycrystals changes as a function of sintering pressure (Hunt et al. 2016). Here we used high resolution transmission electron microscopy to study the structure of grain boundaries from polycrystals synthesized at low (4-8 GPa) and high (8-15) GPa sintering pressure. The HRTEM data were acquired using an image-corrected JEOL ARM 300 to achieve the highest resolution at low electron doses using a OneView camera. Our data indicate a grain boundary structural change occurs from “low-pressure” to “high pressure” grain boundaries, where the grain boundary facets change from >100 nm – 20 nm to 3-7 nm length scale, respectively. We conclude that sintering pressure affects grain-boundary strength and we will evaluate how this may influence anelastic energy loss of seismic waves through elastic or diffusional accommodation of grain-boundary sliding.

Polycrystalline olivine samples show different viscosity related to grain boundary segregation of impurities. To investigate if the distribution of grain boundaries is affected by grain boundary chemistry, we analysed grain orientation data from over 4x104 grains, corresponding to more than 6000 mm grain boundary length per sample. Using stereology, we extract the geometry of the interfacial network. The thus obtained grain boundary character distribution (GBCD) is discussed in relation to bulk viscosity.
Hack the Arctic: transforming data into solutions as a community  
Authors: Buenrostro Mazon Stephany , Brus Magdalena , Ahlgren Katri , Mahura Alexander , Lappalainen Hanna K. , Kulmala Markku
Published: March 2021

A recurring question among research projects is how to optimize the use data that already exists and to identify its stakeholder’s needs, particularly in effort to bring services to a wider community outside academia. We propose a hackathon to allow the collaboration between civil, educational, business and governmental actors to address environmental challenges with the use of environment scientific data from international projects.

Hack the Arctic is co-organized by the Institute for Atmospheric and Earth System Research (INAR)/University of Helsinki, the Integrated Carbon Observation System Research Infrastructure (ICOS-ERIC) Headoffice, and the Environmental Research Infrastructures (ENVRI) Community. The hackathon event aims to enhance the usage and impact of environmental research data by and for society. The 48 hr event will gather multi-disciplinary teams through a public call to make use of existing environmental data from a network of research projects to develop services addressing the needs of different end-users. The participating teams will be mentored by researchers and data scientist in the use of the data. A panel of judges comprising of science mentors, innovation specialists and government sector actors will assess the implementation of the final pilot products at the end of the event.

We present Hack the Arctic as an up-and-coming alternative to expand the usage and visibility of research data and to make it widely accessible to a broader (nonacademic) audience by offering mentorship from data and scientific experts under one roof.
Centimeter-scale-resolution airborne temperature measurements in clouds and in marine surface layer during EUREC4A 
Authors: Król Stanisław , Malinowski Szymon , Kumala Wojciech , Nowak Jakub , Grosz Robert , Posyniak Michał , Lachlan-Cope Tom , Blyth Alan , Boeing Steve
Published: March 2021

Characterization of small-scale temperature structure of convective clouds and their environment is crucial to understand turbulent entrainment, mixing and its effect on cloud dynamics and microphysics. A newly constructed ultra-fast thermometer UFT2, developed from the former UFT-M, allowing for temperature measurements in clouds with the resolution better than few centimeters, was deployed on the British Antarctic Survey Twin-Otter research aircraft in the course of the EUREC4A research campaign. The goal was to perform first ever fine-scale temperature characterization of subtropical marine warm cumulus clouds.

The prototype instrument worked relatively well and allow to collect data from 7 of 17 research flights, including hundreds of cloud penetrations and segments of flights in the marine surface layer. Data, collected with 20 kHz sampling rate, after filtering and averaging allowed to achieve physical resolution of ~3cm at ~60m/s true air speed of the aircraft.

Performance of the UFT-2 sensor and its calibration will be discussed. The discussion will be illustrated with examples of multi-scale temperature records collected in cloud interiors, cloud edges, cloud shells at various altitudes as well as in the marine surface layer ~30 m above the sea level.
The stress field model of the South China Sea calculated by sea level data from satellites
Authors: Shi Han , Gao Jinyao , Xu Mingju , Guan Qingsheng
Published: March 2021

The South China Sea (SCS) is situated at the junction of Eurasian, Indo-Australian, and Philippine sea plates. Its stress state provides significant information about the regional tectonic structure associated with interaction among the three plates. The stress field of the SCS is composed of horizontal and vertical stress fields. We calculate the vertically averaged deviatoric stress field using horizontal gradients of gravitational potential energy obtained by high-resolution sea-surface height data (SSH) from satellite Haiyang-2A. The vertical tectonic stress field is computed based on the Bouguer gravity anomaly derived from SSH and topographic data.

The vertically averaged deviatoric stress field is consistent with the GPS velocity field, the focal mechanism, and the mantle flow stress field of the South China Sea. Moreover, it also indicates the Red River-Ailaoshan Fault zone on the west of the SCS and the Manila subduction on the east. The vertical tectonic stress field removing the influence of sediment indicates upward stress of the lithosphere in the SCS ocean basin. The stress field model therefore provides a powerful tool for understanding regional tectonic activities around the SCS.
Concentration and velocity measurements in experimental turbidity currents 
Authors: Buffon Patricia , Valero Daniel , Uijttewaal Wim , Franca Mário
Published: March 2021

Turbidity currents are in the range of highly sediment concentrated flows, challenging traditional (i.e. optical and acoustic) techniques that aim to measure concentration and velocity quantities. In typical laboratory conditions, difficulties increase in the presence of highly non-uniform and unsteady flows. However, the measurement of those quantities along with a longitudinal profile is necessary to quantify and depict key mechanisms of mass and momentum transport, related to the mean and turbulent flow fields. The possible solutions often require prohibitive costs or resources. In this work, visual, acoustic, electrical, and statistical tools are tested. The aim of these tests is to find appropriate techniques and strategies for measuring concentration and velocity quantities in the broader research scope involving turbidity currents triggered by a 2D water jet. The outcomes will be applied in the quantification of turbidity currents with various boundary and initial conditions in a flume 4 m long, 2 m deep, and 22 cm wide. Additionally, the findings can potentially be transferred to other laboratory applications involving turbidity currents or other types of sediment-laden flows.

Acknowledgements: CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, a Foundation within the Ministry of Education in Brazil), grant number 88881.174820/2018-01.
Climate sensitivity and the Southern Ocean: the effect of the "too few, too bright" model cloud problem
Authors: Kuma Peter , Bender Frida
Published: March 2021

Equilibrium climate sensitivity (ECS) and transient climate response (TCR) are some of the most fundamental properties characterising the future climate. Progress in estimating climate sensitivity over the last three decades has been hampered by a large climate model spread of ECS and TCR estimates, and more recently by a large increase in ECS predicted by several models in the latest generation of the Climate Model Intercomparison Project 6 (CMIP6). Clouds have been identified as the major source of this uncertainty and the recent increase in estimated ECS. A "too few, too bright" model cloud problem has been found in several regions of the globe, including tropical latitudes and the Southern Ocean. Southern Ocean has also been a major focus of changes in model microphysics in an effort to simulate more realistic supercooled liquid clouds. Here, we focus on the too few, too bright problem in the Southern Ocean in CMIP6 models and its possible relation to climate sensitivity. We explore the possibility of applying new emergent constraints on climate sensitivity based on metrics of the too few, too bright problem. We use satellite and and ship-based observational datasets such as lidar and radiometer observations for constraining climate sensitivity and evaluation of clouds in this region across generations of CMIP models.
Investigation of bias in traditional grouping by means of regularization
Authors: Ciesielski Adam , Forbriger Thomas
Published: March 2021

Harmonic tidal analysis bases on the presumption that since short records and close frequencies result in an ill-conditioned matrix equation, a record of length T is required to distinguish harmonics with a frequency separation of 1/T (Rayleigh criterion). To achieve stability of the solution, tidal harmonics are grouped. Nevertheless, if any additional information from different harmonics within the assumed groups is present in the data, it cannot be resolved. While the most information in each group is carried by the harmonic with the largest amplitude, time series from other harmonics is properly taken into account in estimated amplitudes and phases. However, if the signal from the next largest harmonic in a group is significantly different from the expectation, the grouping parametrization might lead to an inaccurate estimate of tidal parameters. That might be an issue since harmonics in a group do not have the same admittance factor, or if the assumed relationship between harmonics degree 2 and 3 is false.

The bias caused by grouping tidal harmonics can be investigated with methods used for stabilizing inverse problem solutions. In our study, we abandon the concept of groups. The resulting ill-posedness of the problem is reduced by constraining the model parameters (1) to reference values and (2) to the condition that admittance shall be a smooth function of frequency. The mentioned regularization terms are present in the least-squares objective function, and the trade-off parameter between the model misfit and data residuals is chosen by the L-curve criterion. We demonstrate how this method may be used to reveal system properties hidden by wave grouping in tidal analysis. We also suggest that forcing time series amplitude may be more relevant grouping criterion than solely frequency closeness of harmonics.
Mapping Mean Lake Surface from satellite altimetry and GPS kinematic surveys
Authors: Crétaux Jean-Francois , Berge-Nguyen Muriel , Calmant Stephane , Fleury Sara , Satylkanov Rysbek , Bonnefond Pascal
Published: March 2021

Lake water height is a key variable in water cycle and climate change studies, which is achievable using satellite altimetry constellation. A method based on data processing of altimetry from several satellites has been developed to interpolate mean lake surface (MLS) over a set of 22 big lakes distributed on the Earth. It has been applied on nadir radar altimeters in Low Resolution Mode (LRM: Jason-3, Saral/AltiKa, CryoSat-2) in Synthetic Aperture Radar (SAR) mode (Sentinel-3A), and in SAR interferometric (SARin) mode (CryoSat-2), and on laser altimetry (ICESat). Validation of the method has been performed using a set of kinematic GPS height profiles from 18 field campaigns over the lake Issykkul, by comparison of altimetry’s height at crossover points for the other lakes and using the laser altimetry on ICESat-2 mission. The precision reached ranges from 3 to 7 cm RMS (Root Mean Square) depending on the lakes. Currently, lake water level inferred from satellite altimetry is provided with respect to an ellipsoid. Ellipsoidal heights are converted into orthométric heights using geoid models interpolated along the satellite tracks. These global geoid models were inferred from geodetic satellite missions coupled with absolute and regional anomaly gravity data sets spread over the Earth. However, the spatial resolution of the current geoid models does not allow capturing short wavelength undulations that may reach decimeters in mountaineering regions or for rift lakes (Baikal, Issykkul, Malawi, Tanganika). We interpolate in this work the geoid height anomalies with three recent geoid models, the EGM2008, XGM2016 and EIGEN-6C4d, and compare them with the Mean Surface of 22 lakes calculated using satellite altimetry. Assuming that MLS mimics the local undulations of the geoid, our study shows that over a large set of lakes (in East Africa, Andean mountain and Central Asia), short wavelength undulations of the geoid in poorly sampled areas can be derived using satellite altimetry. The models used in this study present very similar geographical patterns when compared to MLS. The precision of the models largely depends on the location of the lakes and is about 18 cm, in average over the Earth. MLS can serve as a validation dataset for any future geoid model. It will also be useful for validation of the future mission SWOT (Surface Water and Ocean Topography) which will measure and map water heights over the lakes with a high horizontal resolution of 250 by 250 meters.
Biostratigraphy and microfacies of the sedimentary sequences within volcano-sedimentary Maden Complex in Southeastern Turkey
Authors: Atakul-Özdemir Ayşe , Özkan-Altıner Sevinç , Tancan Sesil , Özdemir Yavuz , Mercan Çağrı , Oyan Vural , Güleç Nilgün
Published: March 2021

Maden Complex is a volcano-sedimantary unit, mainly composed of shallow and deep marine sedimentary rocks and associated volcanics. Deep marine units of Maden Complex, exposed between Çatak (Van) and Kozluk (Batman) regions have been studied with a combined sedimentological and paleontological approaches. The following species are recorded within the Melefan formation: Morozovella aragonensis, Acarinina collactea, Acarinina cf. esnehensis, Acarinina soldadoensis, Acarinina boudreauxi, Acarinina bullbrooki, Acarinina mckanni, Acarinina pentacamerata, Acarinina cf. pseudosubsphaerica, Acarinina topilensis, Acarinina esnehensis, Chiloguembelina sp., Globanomalina planoconica, Globanomalina australiformis, Globigerinatheka sp., Parasubbotina hagni, Pearsonites broedermanni, Pseudoglobigerinella bolivariana,   Planoglobanomalina pseudoalgeriana, Pseudohastigerina wilcoxensis,  Subbotina roesnaensis, Subbotina yeguaensis. Based on the defined planktonic foraminiferal species, the unit corresponds to the E7 zone and the depositional age of the formation is proposed as Early Eocene (Ypresian) to Middle Eocene (Lutetian). The deep marine sedimentary sequence mainly consists of pinkish to red colored micritic limestones including shale intercalations. The formation is represented by the pelloidal wackestone-packstone facies and comprises abundant planktonic foraminiferal assemblages.
LysimeterGEO for modelling soil-vegetation-atmosphere 1D system in the Critical Zone
Authors: D'Amato Concetta , Tubini Niccolò , Rigon Riccardo
Published: March 2021

Measuring and modelling of water and solute fluxes in the Critical Zone across soil-vegetation-atmosphere system is nowadays a very important challenge because of the complexity of both soil and plants. Considering the one-dimensional problem, we implement a virtual lysimeter model, LysimeterGEO, in which we coupled infiltration and evapotranspiration by using stress factor (Jarvis, 1976; Ball et al., 1987), with which we can compute effective evapotranspiration and remove it from Richards’ equation balance (Casulli and Zanolli, 2010).

As regards the IT implementation, LysimeterGEO is a system of components built upon the Object Modelling System v3 (OMS3). The infiltration component of the virtual lysimeter is WHETGEO 1D - Water, Heat and Transport in GEOframe (Tubini N. 2021), which solves the mass and energy balance for the one-dimensional case. The mass balance is represented by the Richards equation and the non-linear system is solved using the nested Newton algorithm (Casulli and Zanolli, 2010). Evapotranspiration flows are instead estimated using the GEOframe-Prospero model (Bottazzi M. 2020) which estimates the effective transpiration through the equilibrium temperature of the canopy as a function of the stomatal conductance. Finally, the transpiration is calculated starting from the method of Schymanski and Or (2017) and modified by including the dependence on the transpiring surface, the model of conductance of the stomata, as well as the conservation of mass. In LysimeterGEO the interaction between infiltration and evapotranspiration is made possible by BrokerGEO component (D’Amato C. 2021), which computes the water stress factor for vegetation by using Jarvis or Ball-Berry model. BrokerGEO computes the water stress factor considering the water content information by WHETGEO in each control volumes of the soil column discretization. Moreover, it computes a representative water stress factor for the whole column of soil for the evapotranspiration component. Finally, the density root distribution is considered to remove water into the soil used for evapotranspiration flows.

The modelling of water and solute fluxes across soil-vegetation-atmosphere is made possible by implementation of travel times of waters within vegetation, the growing of the roots and in general the growing of the plants. The idea of a joint infiltration-evapotranspiration model allows us to investigate also problems related to radical growth and the different effect of roots on vegetation. Furthermore, the implementation of travel times on a vegetation scale allows a careful analysis of the behaviour of the same as the soil moisture conditions vary.
Evolution of Wangtu Gneissic Complex and its paleogeographic implications in Columbia assembly: insights from geochemistry, geochronology, and computational phase-equilibria study
Authors: Hifzurrahman  , Nasipuri Pritam , Raza Mohd Baqar , Ganaie Ab Majeed
Published: March 2021

A part of Palaeoproterozoic granite-gneiss complex, commonly known as Wangtu Gneissic Complex (WGC), exposed in Wangtu-Karcham-Akpa region along the Sutlej valley, northwest lesser Himalaya, India. The core part of this gneissic complex is exposed as the undeformed granitoid body. The basement of WGC is still more or less in its primeval condition. The Paleoproterozoic thermal evolution of the North Indian Continental Margin is uncertain as the Lesser Himalayan granites are viewed either as a subduction-zone volcanic arc or rift-related magmatism during the Columbia assembly or disintegration process. Integrated mineralogical, geochemical analyses, temperature calculations of Ti solubility in biotite and zircon, and computational phase equilibria modelling of the Wangtu Gneissic Complex (WGC), Himachal Himalaya show a peraluminous existence for most WGC rocks that crystallize at a temperature of ~650°C at a pressure of ~1.0-1.1 GPa. The WGC magmatic zircons' U-Pb ages indicate two significant age groups at 1867 Ma and 2487 Ma.

The U-Pb zircon data and model phase equilibria for metasedimentary rock show the generation of S-type peraluminous magma parental to the WGC, by melting pre-existing supracrustal rocks at ~ 1800 Ma, at temperature ~ 850-900 ° C and pressure 1.1-1.2 GPa, identical to P-T conditions found in modern-day subduction zone settings. Also, TDM model ages vary between 3.07 Ga and 2.28 Ga, and f Sm/Nd values (-0.4930 to -0.3510) of the studied samples suggest a contribution of Achaean crust. This study shows that the North Indian Continental Margin was an active subduction zone during the Paleoproterozoic Columbia supercontinent assembly.
Terrestrial-aquatic ecosystem links on the Tibetan Plateau inferred from sedaDNA shotgun sequencing
Authors: Liu Sisi , R. Stoof-Leichsenring Kathleen , Schulte Luise , H. Zimmermann Heike , Mischke Steffen , Herzschuh Ulrike
Published: March 2021

Climate change and associated species interactions are responsible for many vital mechanisms governing the dynamics of ecological communities. However, the long-term contribution of environmental conditions and species connections to community assembly remain mostly unknown. Here, we present changes of terrestrial and freshwater communities based on metagenomic shotgun data retrieved from lacustrine sediments of an alpine freshwater lake on the south-eastern Tibetan Plateau (Hengduan Mountains) covering the past 15,100 thousand years (ka). Terrestrial assemblages between 15.1-14 ka are explained by the harsh environment and facilitative interactions due to diverse cushion plants, while the abundant ice-age algae (Nannochloropsis and N. limnnetica) indicate dominance of glacial meltwaters. A sharp decrease in alpine herbs (e.g Asteraceae, Carex and Poaceae) corresponded to competitive interactions with the colonization of woody plants (Salicaceae, Salix, Rhododendron and R. delavayi) since 14 ka, leading to a decline of large herbivores (Bovidae and Bos mutus) that predominated. Meanwhile, the disappearance of ice-age algae and the expansion of submerged plants (e.g., Potamogeton, P. perfoliatus, Myriophyllum, and M. spicatum) are consistent with an increase in temperature and a plentiful supply of nutrients due to weathering and soil erosion. The loss of submerged plants during the late Holocene (~3.6 ka) is probably related to environmental deterioration; however, it could also be related to the Cyanobacteria boom. Our study highlights that shotgun sequencing of lake sediments is an important tool for exploring ecological processes of communities in the past.
Karst evolution, hydrocarbon and geothermal resources in flow system context (South Hungary)
Authors: Csondor Katalin , Csobaji Lehel , Zentai-Czauner Brigitta , Győri Orsolya , Erőss Anita
Published: March 2021

In South Transdanubia (Hungary) there are remarkable geothermal and hydrocarbon resources. The area is also characterized by natural thermal water discharge at the boundary of outcropping carbonate hills and adjacent sedimentary basin. These regional discharge areas are favourable sites of hypogenic caves as well. These geofluid systems and groundwater related phenomena are usually investigated separately and their interactions are just neglected. The aim of this study is to give all these groundwater-related resources and phenomena a common framework applying the concept of regional hydraulic continuity, and to complete the basin-scale hydraulic assessment of the area based on preproduction archival measured data. Pressure-elevation profiles, tomographic fluid-potential maps and hydraulic cross-sections were constructed to determine the vertical and horizontal fluid-flow conditions. As a result, two kinds of fluid flow systems could be identified. Within the gravitational flow systems, horizontal flow conditions are dominant and the regional flow direction tends toward the S–SE. In deeper basin regions, an overpressured flow system is prevalent, where fluids are driven laterally from the deeper sub-basins towards their margins. Based on the regional-scale evaluation of fluid flow systems, conclusions could be drawn regarding the geothermal and hydrocarbon potential of the area. Additionally, local-scale phenomena could be explained, and the study emphasizes that knowledge on regional groundwater flow systems is essential to understand local scale groundwater-related phenomena such as recent cave formation in an area. A comparison with the marginal Buda Thermal Karst area allows for generalized conclusions regarding the connections between marginal karst reservoirs and the Pannonian Basin. Furthermore, the results of the study can be directly applied in the exploration and sustainable utilization of groundwater related resources, such as thermal waters and hydrocarbons.

This topic is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 810980. The National Research, Development and Innovation Fund has provided financial support to the research under the grant agreement no. PD 116227.
Parker Solar Probe Observations of Alfvénic Waves and Ion-cyclotron Waves in a Small-scale Flux Rope
Authors: Shi Chen , Zhao Jinsong , Huang Jia , Wang Tieyan , Wu Dejin , Chen Yu , Hu Qiang , Kasper Justin C. , Bale Stuart D.
Published: March 2021

Magnetic flux ropes can play important roles in transferring the mass, momentum, and energy in the interplanetary environment and in affecting space weather. Small-scale flux ropes (SFRs) are common in the interplanetary environment. However, SFRs with medium and high Alfvénicity are generally discarded in previous identification procedures. Using Parker Solar Probe measurements, we identify an SFR event with medium Alfvénicity in the inner heliosphere (at ~ 0.2 au). Based on high correlations between the magnetic field and velocity fluctuations, we show Alfvénic waves arising inside such SFR. We also show occurrence of quasi-monochromatic electromagnetic waves at the leading and trailing edges of this SFR. These waves are well explained by the outward-propagating ion-cyclotron waves, which have wave frequencies ~ 0.03 - 0.3 Hz and wavelengths ~ 60 - 2000 km in the plasma frame. Furthermore, we show that the power spectral density of the magnetic field in SFR middle region follows the power-law distribution, where the spectral index changes from -1.5 (f <~ 1 Hz) to -3.3 (f >~ 1 Hz). These findings would motivate developing an automated program to identify SFRs with medium and high Alfvénicity from Alfvénic waves structures.
Cross helicity of magnetic clouds observed by Parker Solar Probe
Authors: Good Simon , Kilpua Emilia , Ala-Lahti Matti , Osmane Adnane , Bale Stuart , Zhao Lingling
Published: March 2021

Magnetic clouds are large-scale transient structures in the solar wind with low plasma β, low-amplitude magnetic field fluctuations, and twisted field lines with both ends often connected to the Sun. We analyse the normalised cross helicity, σc, and residual energy, σr, in magnetic clouds observed by Parker Solar Probe (PSP). In the November 2018 cloud observed at 0.25 au, a low value of σc was present in the cloud core, indicating that wave power parallel and anti-parallel to the mean field was approximately balanced, while the cloud’s outer layers displayed larger amplitude Alfvénic fluctuations with high σc values and σr ~ 0. These properties are compared and contrasted to those found in clouds observed by PSP at larger heliocentric distances. We suggest that low σc is likely a common feature of magnetic clouds given their typically closed field structure, in contrast to the generally higher σc found on the open field lines of the solar wind.
Reconstructing the runoff and mass changes of a maritime Tibetan glacier since 1975
Authors: Jouberton Achille , Shaw Thomas E. , Miles Evan , Ren Shaoting , Yang Wei , Zhao Chuanxi , McCarthy Michael , Fugger Stefan , Dehecq Amaury , Pellicciotti Francesca
Published: March 2021

Glaciers are key components of the water towers of Asia and as such are relied upon by large downstream communities for domestic, agricultural and industrial uses. They have experienced considerable shrinking over the last decades, with some of the highest rates of mass loss observed in the south-eastern part of the Tibetan Plateau, where mass loss is also accelerating.  Despite these rapid changes, Tibetan glaciers’ changing role in catchment hydrology remains largely unknown. Parlung No.4 Glacier is considered as a benchmark glacier in this region, since its meteorology, surface energy fluxes and mass-balance have been examined since 2006. It is a maritime glacier with a spring (April-May) accumulation regime , which is followed by a period of ablation during the Indian Summer Monsoon (typically June-September). Here, we conduct a glacio-hydrological study over a period of five decades (1978-2018) using a fully distributed model for glacier mass balance and runoff simulation (TOPKAPI-ETH). We force the model with ERA5-Land and China Meteorological Forcing Dataset (CMFD) climate reanalysis downscaled to a local weather station to reconstruct meteorological time series at an hourly resolution. TOPKAPI-ETH is calibrated and validated with automatic weather station data, discharge measurements, geodetic mass balance, stake measurements and snow cover data from MODIS. We find a very clear acceleration in mass loss from 2000 onwards, which is mostly explained by an increase in temperature. This influence however was initially compensated by an increase in precipitation until the 2000’s, which attenuated the negative trend. Our results also indicate that the increase in the liquid-solid precipitation ratio has reduced the amount of seasonal accumulation, exacerbating annual mass loss. We demonstrate that the southern westerlies and the associated spring precipitation have as much influence on the glacier mass balance and catchment discharge as the Indian Summer Monsoon, by controlling seasonal snowpack development, which simultaneously provides mass to the glacier and protects it from melting in the early stage of the monsoon.
Effects of ageing under field conditions on soil organic matter in earthworm casts produced by the anecic earthworm Amynthas adexilis in northern Vietnam
Authors: Puche Nicolas Jean Bernard , Rumpel Cornelia , Bottinelli Nicolas
Published: March 2021

Carbon sequestration in soils became a major issue that governments have to face under their sustainable development objectives and the international 4p1000 program. Although, earthworms are recognized to play a key role in the structure and dynamics of organic matter (OM) in soils, their contribution to soil OM cycling is not taken into account in biogeochemical models nor well understood. In particular, the fate of OM protected in earthworm casts is unknown. In this study, we investigated the effects of ageing under field conditions on the OM dynamics contained in casts produced by the anecic earthworm Amynthas adexilis in North Vietnam. To this end we investigated (1) the microscale organisation of particulate organic matter and pores during the exposure of casts and control aggregates during 12 months and (2) compared it to the potential OM mineralisation during a laboratory incubation.

Our results indicated that fresh casts contained significantly more particulate organic matter (POM) than control soil aggregates and field aged earthworm casts. Conversely, the porosity was higher in soil control aggregates than in casts and the porosity of casts tended to increase with their ageing. The analyses of micro-CT images also revealed that POM and Pores contents between casts samples presented strong variabilities even in the youngest casts category. We found, on average, higher mineralisation rates for casts than for controls and a reduction of the OM mineralisation with the ageing of casts. Our results also highlighted a strong positive correlation (r2 = 0.89) between POM contents determined by the segmentation of micro CT images and CO2 emissions from the incubation experiment. We conclude that earthworms impact the microscale organisation of POM and pores in their casts and thereby influence soil OM dynamics.
Sea state trends and variability: consistency between the ESA Sea State Climate Change Inititative dataset, ERA5 winds and microseisms
Authors: Alday Matias , De Carlo Marine , Dodet Guillaume , Accensi Mickael , Stutzmann Eleonore , Ardhuin Fabrice , Bidlot Jean
Published: March 2021

Abstract: Wave hindcasts of long time series ( > 30 years) have been instrumental in understanding the wave climate. However, it is still difficult to have a consistent reanalysis suitable for study of trends and interannual variability. Here we explore the consistency of wave hindcast with independent observations from moored buoys, satellite altimeters, and  microseism data. We use the ECMWF 5th generation re-analysis (ERA5) winds to drive two wave models, using either ECMWF WAM (Bidlot et al. 2019) or WAVEWATCH III (The WAVEWATCH III Develoment Group 2019, Alday et al. 2020). We also use seismic data in the dominant double-frequency band, around 5 s period, that are generated by opposing waves of equal frequencies and compare these to modeled microseims. We find that the inter-platform corrections in the ESA CCI Version 1.1 dataset (Dodet et al. 2020) introduced a trend that differs from the microseism trends. However, the results converge when using a revised correction of this dataset. We also look at the microseism spectral signature of large storms in the North Atlantic and discuss how we may compare the severity of different storms that move over different ocean bathymetry with different wave to microseism conversions. 

References: Stopa, J. E., Ardhuin, F., Stutzmann, E., & Lecocq, T. (2019).  Sea state trends and variability: Consistency between models, altimeters, buoys, and seismic data (1979–2016). Journal of Geophysical Research: Oceans, 124. https://doi.org/10.1029/2018JC014607 

Dodet, G., Piolle, J.-F., Quilfen, Y., Abdalla, S., Accensi, M., Ardhuin, F., Ash, E., Bidlot, J.-R., Gommenginger, C., Marechal, G., Passaro, M., Quartly, G., Stopa, J., Timmermans, B., Young, I., Cipollini, P., and Donlon, C.: The Sea State CCI dataset v1: towards a sea state climate data record based on satellite observations, Earth Syst. Sci. Data, 12, 1929–1951, https://doi.org/10.5194/essd-12-1929-2020 , 2020.
Microbarometer arrays for the monitoring of extreme weather in a changing climate
Authors: Assink Jelle
Published: March 2021

A global network of microbarometer arrays has been installed for the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) using infrasound. The microbarometers also measure pressure variations that are due to various meteorological phenomena, such as gravity waves, with a resolution that exceeds that of typical barometers. Moreover, the use of array technology allows for the estimation of wavefront parameters, which is information that can generally not be obtained from typical automatic weather stations.

The value of these high-resolution observations for the monitoring of extreme weather is discussed here, focusing on two recent extreme weather events in The Netherlands. Data from a dense observational network that includes lidar facilities and the Dutch microbarometer array network is compared to forecasts from global and regional weather forecast models to assess the forecast skill of the state-of-the-art weather models. The first-order agreement suggests that microbarometer arrays could provide valuable data for the development of next-generation weather forecast models. Such developments are useful for Early Warning Centers that report on severe weather outbreaks that can be disruptive for society and which are expected to occur more frequently in a changing climate.

This presentation demonstrates that the infrasound technology, as a civil and scientific application, could aid in the forecasting of extreme weather events that are predicted to occur more frequently in a changing climate.