bluuebunny/crossref_metadata_2025 huggingface dataset:
Precision description for remote sensing glacier velocity data
Authors: Altena Bas , Kääb Andreas , Wouters Bert
Published: March 2022

A large amount of velocity data is now becoming available through portals, pipelines and repositories. Typically the error characterisation for these individual velocity fields or mosaics is done through sampling statistics, resulting in a proxy of precision for the whole dataset. However even within a scene pair, the appearance can change considerably, or be stable at nearby locations. For example, think of regions close to the transient snowline, or an elongated moraine band, a  crevasse train after a bump or a shear zone. Here the precision of localising an exact image match is clearly anisotropic. If such anisotropic precision estimates are taken into account, it is possible to provide a more correct error-propagation. The merit of velocity data can be found in the help for inversion for thickness estimates (as it is related to the fourth power), or shear and strain rates. Here we introduce a simple and fast methodology to generate an individual dispersion estimate, based upon the similarity surface of an image match. A linear least squares adjustment of the neighbouring similarity scores is sufficient to fit an oriented gaussian peak. This setup makes the computation fast and is easy to implement into already available processing pipelines. We demonstrate its effectiveness on two glaciers, Sermeq Kujalleq, a large outlet glacier of the Greenland icesheet, with strong shear margins and Malaspina Glacier a piedmont glacier with looped moraines. We find directionality within an image subset to be the dominant factor influencing the correlation dispersion. This stems from crevasses and moraine bands within the imagery, while a relation to differential flow, such as shear, is less pronounced. It is our hope, this methodology will narrow the integration gap between models and measurements.
Petrological evidence for focussed mid-crustal magma intrusion in the Main Ethiopian Rift
Authors: Wong Kevin , Ferguson David , Wieser Penny , Morgan Daniel , Edmonds Marie , Tadesse Amdemichael Zafu , Yirgu Gezahegn
Published: March 2022

Rifting in Ethiopia is predominantly driven by magmatic intrusion into the rifting crust. Unravelling the dynamics of lithospheric melt migration and storage is paramount to understanding the late-stage development of continental rifts. In particular, extensive geophysical observations of the structure and composition of rifting crust must be supported by petrology to provide a complete picture of rift-related magmatism. We present major element, trace element, and volatile element compositional data for olivine-hosted melt inclusions from the Boku Volcanic Complex (BVC), a monogenetic cone field in the north Main Ethiopian Rift. Through combined CO2-density-calibrated Raman spectroscopy and secondary ion mass spectrometry we assess the total CO2 concentrations within the melt inclusions allowing us to estimate pressures of entrapment via CO2-H2O solubility models. Our results show that primitive BVC melts carry up to 0.58 wt% CO2 (mean ~0.2 wt%), with as much as half of the CO2 in the melt inclusion present within shrinkage bubbles. Volatile solubility models suggest that these melts are stored over a narrow range of depths (10-15 km), consistent with geophysical data and implying the existence of focussed zone of magma intrusion at mid-crustal depths. The expansive range of trace element concentrations in the inclusions illustrate that, at the time of entrapment, compositional heterogeneity remains extant, and melts must therefore be stored in discrete magmatic bodies with limited mixing. Our results have implications for understanding the interplay between magma intrusion and extensional tectonics during continental break-up, such as magmatic compensation of crustal thinning and the thermo-mechanical effects of melt emplacement into the rifting crust.
Investigating the variation of the ionospheric absorption during large solar flares based on modern Digisonde data
Authors: Buzás Attila , Burešová Dalia , Kouba Daniel , Mošna Zbyšek , Barta Veronika
Published: March 2022

As a result of the enhanced X-ray and EUV fluxes following large solar flares, the electron density of the ionospheric layers increases. Furthermore, it causes higher absorption or even partial or total fade-out of the emitted radio waves which can be measured with ionosondes and Digisondes by studying the amplitude of the reflected electromagnetic waves [1,2].

In the present study, the ionospheric response to large solar flares has been investigated using the ionosonde data measured at the Průhonice (Czech Republic, 49.98° N, 14.55° E) and San Vito (Italy, 40.6° N, 17.8° E) stations in September 2017, the most active solar period of Solar Cycle 24. A novel method [3]  to calculate and investigate the absorption of radio waves propagating in the ionosphere is used to determine the absorption during large solar flare events (M and X class). Subsequently, the absorption data are compared with the indicators derived from the fmin method (fmin, the minimum frequency is considered as a qualitative proxy for the “nondeviative” radio wave absorption occurring in the D-layer). Total and partial radio fade-out and increased values (with 2–5 MHz) of the fmin parameter were experienced during and after the intense solar flares (> M3). Furthermore, the signal-to-noise ratio (SNR) measured by the Digisondes was used as well to quantify and characterize the fade-out events and the ionospheric absorption. The combination of these three methods may prove to be an efficient approach to monitor the ionospheric response to solar flares.

[1] Sripathi, S., Balachandran, N., Veenadhari, B., Singh, R., and Emperumal, K.: Response of the equatorial and low-latitude ionosphere to an intense X-class solar flare (X7/2B) as observed on 09 August 2011, J. Geophys. Res.-Space, 118, 2648–2659, 2013.

[2] Barta, V., Sátori, G., Berényi, K. A., Kis, Á., and Williams, E. (2019). Effects of solar flares on the ionosphere as shown by the dynamics of ionograms recorded in Europe and South Africa. Annales Geophysicae, Vol. 37, No. 4, pp. 747-761

[3] Sales, G. S., 2009, HF absorption measurements using routine digisonde data, Conference material, XII. International Digisonde Forum, University of Massachusetts
Attributing land water storage trends from satellite gravimetry to long-term wetting and drying conditions with global climate models
Authors: Jensen Laura , Eicker Annette , Dobslaw Henryk
Published: March 2022

Global and interactively coupled climate models are important tools for projecting future climate conditions. Even though the quality and reliability of such models has increased during the most recent years, large model uncertainties still exist for various climate elements, so that it is crucial to continuously evaluate them against independent observations. Changes in the distribution and availability of terrestrial water storage (TWS), which can be measured by the satellite gravimetry missions GRACE and GRACE-FO, represent an important part of the climate system in general, and the terrestrial water cycle in particular. However, the use of satellite gravity data for the evaluation of interactively coupled climate models has only very recently become feasible. Challenges mainly arise from large model differences with respect to land water storage-related variables, from conceptual discrepancies between modeled and observed TWS, and from the still rather short time series of satellite data.

This presentation will highlight the latest results achieved from our ongoing research on climate model evaluation based on the analysis of an ensemble of models taking part in the Coupled Model Intercomparison Project Phase 6 (CMIP6). We will focus on long-term wetting and drying conditions in TWS, by deriving several hot spot regions of common trends in GRACE/-FO observations and regions of large model consensus. However, as the observational record currently only covers about 20 years, observed trends may still be obscured by natural climate variability. Therefore, to further attribute the wetting or drying in the identified hot spot regions to either interannual/decadal variability or anthropogenic climate change, we investigate the influence of dedicated climate modes (such as ENSO, PDO, AMO etc.) on TWS variability and trends. Furthermore, we perform a numerical model investigation with 250 years of CMIP6 TWS data to quantify the degree to which trends computed over differently long time intervals can be expected to represent long-term trends, and to discriminate regions of rather robust trends from regions of large fluctuations in the trend caused by decadal climate variability.
Two-dimensional hydrodynamic robust numerical model of soil erosion based on slopes and river basins
Authors: yongde kang
Published: March 2022

Erosion is an important issue in soil science and is related to many environmental problems, such as soil erosion and sediment transport. Establishing a simulation model suitable for soil erosion prediction is of great significance not only to accurately predict the process of soil separation by runoff, but also improve the physical model of soil erosion. In this study, we develop a graphic processing unit (GPU)-based numerical model that combines two-dimensional (2D) hydrodynamic and Green-Ampt (G-A) infiltration modelling to simulate soil erosion. A Godunov-type scheme on a uniform and structured square grid is then generated to solve the relevant shallow water equations (SWEs). The highlight of this study is the use of GPU-based acceleration technology to enable numerical models to simulate slope and watershed erosion in an efficient and high-resolution manner. The results show that the hydrodynamic model performs well in simulating soil erosion process. Soil erosion is studied by conducting calculation verification at the slope and basin scales. The first case involves simulating soil erosion process of a slope surface under indoor artificial rainfall conditions from 0 to 1000 s, and there is a good agreement between the simulated values and the measured values for the runoff velocity. The second case is a river basin experiment (Coquet River Basin) that involves watershed erosion. Simulations of the erosion depth change and erosion cumulative amount of the basin during a period of 1–40 h show an elevation difference of erosion at 0.5–3.0 m, especially during the period of 20–30 h. Nine cross sections in the basin are selected for simulation and the results reveal that the depth of erosion change value ranges from –0.86 to –2.79 m and the depth of deposition change value varies from 0.38 to 1.02 m. The findings indicate that the developed GPU-based hydrogeomorphological model can reproduce soil erosion processes. These results are valuable for rainfall runoff and soil erosion predictions on rilled hillslopes and river basins.
Uncertainty of uncertainty decomposition approaches for projections of hydrological extremes
Authors: Tabari Hossein , Willems Patrick
Published: March 2022

The quantitative description of uncertainty in future projections of hydrometeorological variables provides valuable information for a better interpretation of climate change impact for informed policy decisions and actions to mitigate the associated risk. Several methods have been developed and used for decomposing the uncertainty in projections. The relative importance of the uncertainty associated with the choice of uncertainty decomposition methods compared to the other sources of uncertainty has however never been quantitatively investigated. We scrutinize where and to what extent the rate of fractional uncertainties could vary across the globe depending on the choice of uncertainty decomposition methods. We characterize drought by the standardized precipitation evapotranspiration index (SPEI) using a large ensemble of the Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 6 (CMIP6) general circulation models (GCMs). Flood and extreme precipitation are quantified by fitting a generalized extreme value distribution (GEV) to the annual maxima time series of the ISIMIP2b global hydrological model and CMIP5/CMIP6 simulations. The uncertainty in future projections of extreme precipitation, flood, and drought is then split in the variance contributions using the traditional ANOVA, quasi-ergodic ANOVA (QE-ANOVA), HS09, and variance decomposition-same sample size (VD-SSS) methods. Finally, the uncertainty arising from the choice of uncertainty analysis methods is quantified and compared across different types of hydrological extremes and the IPCC reference regions.
Weak, Seismogenic Faults in the Lower Crust
Authors: Wimpenny Sam
Published: March 2022

Earthquake-generating faults are typically confined to the upper 10-15 km of the crust, with the middle and lower crust deforming aseismically. Along the margins of Earth’s highest mountain ranges, however, seismicity can extend throughout the whole crust, from the surface to depths of 30-50 km in rocks at temperatures of 400-600 degrees. For earthquakes to take place at such high temperatures, the lower crust is thought to have an extremely dry (anhydrous) mineralogy, such that elastic strain is not relaxed by creep.

In this study, I will discuss the mechanical properties of earthquake-generating faults in the lower crust around the Andes mountains. I will use force-balance calculations to demonstrate that faults within the lower crust can be frictionally very weak, with an average effective static coefficient of friction <0.2. The mechanisms invoked to generate similar frictionally-weak, earthquake-generating faults in the upper crust appeal to the presence of highly-pressurised water, or water-driven alteration of the fault core to form phyllosilicate minerals. However, the dry mineralogy thought to necessitate elastic strain accumulation in the lower crust should preclude abundant free water within these faults by acting as a `sponge’, soaking up free water in hydration reactions. The geological controls on the frictional properties of earthquake-generating, lower-crustal faults remain a conundrum.
Characteristics of hail in the Croatian coastal part of the Adriatic
Authors: Blašković Lucija , Jelić Damjan , Malečić Barbara , Omazić Branimir , Telišman Prtenjak Maja
Published: March 2022

Hail is an extreme phenomenon that can cause great material damage. Although the process of hail formation is known, there is still insufficient knowledge about this topic. For this reason, numerous researches on hail climatology around the world have been made in the last few years. In spite of the fact that Croatia is a small country, it has a relatively inhomogeneous climate. The cause of this inhomogeneity may be orography, proximity to the Adriatic Sea etc. Characteristics of hail vary in different climatic conditions, and this research will focus on characteristics of hail in the climactic conditions of costal part of the Adriatic. The results are based on hail data from 55 stations from the observation log for the period from 1973 to 2019, and ERA 5 data for instability indices. The results showed significant interannual and spatial variability, due to which it was necessary to make a division into 4 subdomains. Trend analysis showed negative trend in interannual number of hail events, and the loss of hail events was reflected on summer and autumn seasons. It was shown that on the entire coast, the highest hail activity is present in the colder part of the year, and reduced activity in the warmer part of the year. Daily patterns showed 3 daily highs – morning, noon and afternoon, and the duration was usually 5 minutes. Three stations were singled out as the ones with the most hail days a year: Senj, Drniš and Gračac. Finally, instability indices were studied (KI, CAPE, DLS and freezing level height), which could explain the atmospheric conditions in which hail occurs.
Strategies for building maths skills in a geospatial MSc class using the web based e-assessment software Numbas 
Authors: Petrie Elizabeth
Published: March 2022

Students on the geospatial MSc programmes start with very varied levels of maths experience/skills. The students all need to become capable with all the maths concepts needed for the degree programme, but without boring those who can already do them. The Numbas software is freely available, open source and very mathematically capable (https://www.numbas.org.uk/). It facilitates creation of questions and exams which are randomizable, so students can repeat them many times for practice as needed. The randomizable nature of the questions can also be helpful for remote learning, as everyone has a test with different answers. This work describes how the tests and learning material have been arranged within the module to encourage timely self-learning of maths topics linked to geospatial themes, with initial low stakes assessments followed by higher stakes summative assessment, and discusses experiences with integrating Numbas over the last four years.  
Hybridization of magmas by break down of partially molten granitic rock and its assimilation 
Authors: Hasalová Pavlina , Schulmann Karel , Tabaud Anne-Sophie , Míková Jitka
Published: March 2022

During orogenic processes continental crust experiences significant partial melting. Repeated thermal pulses or fluctuation in fluid content can even cause multiple anatectic events that result in complex intrusion suits. The Vosges Mountains (NE France) reveal two chronologically and geochemically distinct tectono-magmatic events. An early major pulse of Mg‒K magmatism was followed ten millions years later by development of a magma-rich detachment zone and intrusion of Central Vosges Granite forming a felsic MASH zone. This MASH zone is characterized by the production of a large quantity of anatectic melts that interacted with the older Mg‒K granites and surrounding granulites and metasedimentary rocks. We aim to understand how such hybridization processes impact on the crustal rocks rheology, deformation as well as its geochemistry and geochronology. Three different granite varieties were distinguished: (i) the older Mg‒K granite end-member that is coarse-grained with a high proportion of feldspar phenocrysts, zircon U-Pb ages of 340 Ma and specific geochemical signature; (ii) Medium-grained type has a smaller amount of phenocrysts and shows advanced brecciation where fine-grained Pl+Kfs+Qtz form discontinuous corridors to an interconnected network surrounding fractured phenocrysts. Its geochemical signature suggests that this represents a mixing of Mg−K and Central Vosges granites, as confirmed by the presence of both inherited (340 Ma) and younger (330‒310 Ma) zircon domains; (iii) Isotropic medium-grained granite that shows geochemical signature typical for the Central Vosges Granite in which younger zircon domains (310‒320 Ma) dominate over inherited xenocrysts (340 Ma). These three granite varieties represent different stages of magma hybridization by the break up of the older Mg‒K granite by the younger Central Vosges Granite magmas. The interaction between new melt and previously crystallized granitoids results in variety of granite textures, fabrics, chemical compositions, isotopic signatures and deformational behavior. In summary, the resulting signature is result of interplay of melt transfer and interaction in the MASH zone.
Understanding surface-wave modal content for high-resolution imaging with ocean-bottom distributed acoustic sensing
Authors: Spica Zack , Viens Loïc , Perton Mathieu , Nishida Kiwamu , Akuhara Takeshi , Shinohara Masanao , Yamada Tomoaki
Published: March 2022

Ocean Bottom Distributed Acoustic Sensing (OBDAS) is emerging as a new measurement method providing dense, high-fidelity, and broadband seismic observations from fiber-optic cables. Here, we use ~40 km of a telecommunication cable located offshore the Sanriku region, Japan, and apply ambient seismic field interferometry to obtain an extended 2-D high-resolution shear-wave velocity model. In some regions of the array, we observe and invert more than 20 higher modes and show that the accuracy of the retrieval of some modes strongly depends on the processing steps applied to the data. In addition, numerical simulations suggest that the number of modes that can be retrieved is proportional to the local velocity gradient under the cable. Regions with shallow low-velocity layers tend to contain more modes than those located in steep bathymetry areas, where sediments accumulate less. Finally, we can resolve sharp horizontal velocity contrasts under the cable suggesting the presence of faults and other sedimentary features. Our results provide new constraints on the shallow submarine structure in the area and further demonstrate the potential of OBDAS for offshore geophysical prospecting.
Aircraft Engine Dust Ingestion at Major Global Airports
Authors: Ryder Claire , Bezier Clement , Dacre Helen , Clarkson Rory , Marinou Eleni , Proestakis Manolis , Alexiou Alexandros , Amiridis Vassilis , Kipling Zak , Benedetti Anglea , Parrington Mark
Published: March 2022

Mineral dust is the most abundant aerosol in the atmosphere and in particular regions exists in high concentrations. Ingestion of dust by aircraft engines can result in erosion, corrosion or a build-up of deposits damaging internal components. A move towards more efficient engines over recent years restricts capacity to tolerate detrimental impacts in engines. Air traffic in arid areas such as the Middle East has also increased dust exposure. However, it is not currently known how much dust is ingested by aircraft during take-off and landing. In order to quantify this, the vertical profile of dust is required. Here we present a climatology of vertical profiles of dust from the ECMWF Copernicus Atmospheric Monitoring System (CAMS) reanalysis at 10 major global airports, as well as their seasonal and diurnal variability, between 2003-2020. We evaluate the CAMS dust profiles against spaceborne lidar retrievals of dust from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the CALIPSO satellite using both the standard NASA Level 3 product and the LIdar climatology of Vertical Aerosol Structure (LIVAS) product. Finally, using expected aircraft ascent and descent rates and associated mass flow into an engine, dust dose is calculated for take-off, climb, descent, hold, approach, land and taxi phases, as well as for the entire ascent/descent at different airports, using both CAMS and CALIOP datasets.

 

We show that vertical distribution of dust varies significantly between airports and across seasons, which has a large impact on the total engine dust ingestion. Diurnal dust variations at some airports such as Dubai are extremely large, with night time surface concentrations reduced by over 20%.  Vertical profiles from CAMS show considerable differences to the standard CALIOP L3 retrievals, though agreement with LIVAS profiles is much better. Aircraft engine dose is found to be highest for Delhi (where does exceed 7g for a single descent in summer), Niamey and Dubai. During ascent, ingestion is largest during take-off, such that airports with large concentrations of lower altitude dust incur higher doses. During descent, dose is strongly dependent of the altitude of holding pattern relative to the altitude of maximum dust concentration, such that Delhi and Dubai incur the largest dust dose. Therefore, it is recommended that measures to reduce dust ingestion are airport-specific, and could include practices such as night time take-off and adjustment of holding pattern altitude.
Historical and projected heat waves in Croatia
Authors: Srnec Lidija , Magjarević Vjeran , Güttler Ivan
Published: March 2022

Introduction: Last IPCC AR6 reported with very high confidence that more frequent hot extremes will increase for the severity of heatwaves all-round the globe. It is known that heat and hot weather that can last for several days (so called heatwaves) can significantly influence human health as well as rise in heat-related deaths.

Design and methods: In this work, climate simulations obtained by regional climate model RegCM4 over Croatia are used. RegCM4 was forced by four different global climate models on 12.5 km horizontal resolution. Historical climate simulated by model is compared with observed daily data measured at Croatian meteorological stations in order to evaluate simulations. Future climate is considered by three different IPCC scenarios: the lowest RCP2.6, the middle RCP4.5 and the highest RCP8.5 emission scenario. We considered three future time slices: 2021-2050 (P1), 2031-2060 (P2) and 2041-2070 (P3).

Results: The range of climate change for maximum temperature during summer will be examined in the future time slices. We will also look into duration and number of heat waves in different parts of Croatia. Knowledge of the current situation as well as possible change in the future can help in the planning future adaptation and mitigation measures.
A global analysis of water storage variations from remotely sensed soil moisture and daily satellite gravimetry
Authors: Blank Daniel , Eicker Annette , Jensen Laura , Güntner Andreas
Published: March 2022

Information on water storage changes in the soil can be obtained on a global scale from different types of satellite observations. While active or passive microwave remote sensing is limited to investigating the upper few centimeters of the soil, satellite gravimetry can detect changes in the full column of terrestrial water storage (TWS), but cannot distinguish between storage variations occurring in different soil depths. Jointly analyzing both data types promises interesting insights into the underlying hydrological dynamics and may enable a better process understanding of water storage change in the subsurface.

In this study, we investigate the global relationship of (1) several satellite soil moisture (SM) products and (2) non-standard daily TWS data from the GRACE and GRACE-FO satellite gravimetry missions on different time scales. The six SM products analyzed in this study differ in their data source, processing level, and soil depth for which the SM information is provided. Original level-3 surface SM data sets of SMAP and SMOS are compared to post-processed level-4 data products (both surface and root zone SM) and a multi-satellite product provided by the ESA CCI. A tailored temporal and spatial masking has been applied to focus on time spans with favorable signal-to-noise ratio and to exclude periods with snow cover or frozen soil.

We sample all TWS and SM data sets to a common 1 degree spatial resolution, decompose each signal into seasonal to sub-monthly frequencies and carry out the comparison with respect to spatial patterns and temporal variability. We find increasingly large correlations between the TWS and SM for deeper integration depths (root zone vs. surface layer) and for post-processed level-4 data products. Even for highpass-filtered (sub-monthly) variations, significant correlations can be found of up to 0.6 in regions with large high-frequency variability. A time-shift analysis shows differences in the temporal dynamics of soil moisture versus TWS storage variations, indicating different water storage dynamics in the different depth layers. Precipitation data have been added to the analysis to enhance the interpretation of the comparison of soil moisture and total water storage variations.
The Deformation Style of Somma-Vesuvius
Authors: Massa Bruno , Castaldo Raffaele , D’Auria Luca , De Matteo Ada , James Michael R. , Lane Stephen J. , Pepe Susi , Tizzani Pietro
Published: March 2022

The Somma-Vesuvius volcano is one of the most dangerous on the Earth due to its proximity to the city of Napoli (Southern Italy). The volcanic edifice has a typical asymmetric shape: the truncated cone of Mt.  Somma topped by the Vesuvius “Gran Cono”. Somma-Vesuvius last erupted in 1944 and is currently quiescent, experiencing fumarolic activity, low-energy seismicity and slow ground deformation (subsidence of the edifice itself and uplift in the surrounding area). Understanding the deformation style of Somma-Vesuvius and the corresponding long-term structural evolution allows inferences about volcanic activity and associated hazards. A large amount of data has already been collected about Somma-Vesuvius. Nevertheless, the deformation style affecting its volcanic edifice is still matter of debate. We present results of an integrated numerical-analogue modeling approach aimed at refining the current state of deformation of this volcano. Numerical models were built using a Finite Element (FE) method, implemented with a three-dimensional time-dependent fluid-dynamic approach, representative of both 1:100,000 and 1:1 scales. A wide range of laboratory analog models were built at a scale of 1:100,000, using sand mixtures as brittle medium and polydimethylsiloxane as a ductile one. A comparison with the actual Somma-Vesuvius deformation velocity patterns, obtained by differential interferometric synthetic aperture radar (DInSAR) and GPS measurements, allowed the selection of a pair of analog/numerical models that faithfully reproduced the field and remote sensing observations. The modeling procedure adds new constrains supporting a combined gravitational spreading-sagging process governing the deformation of the Somma-Vesuvius volcano. This conclusion has a critical consequence: the recognized deformation processes support the presence of a tensional regime. This has the potential implication of reducing the loading stress on the magmatic reservoir system and, consequently, of decreasing the Volcanic Explosive Index of eruptive events. The refined knowledge of the actual deformation process affecting Somma-Vesuvius should be a key contribution to a reliable volcanic surveillance system.
Observing the Disintegration of the A68A Iceberg from Space
Authors: Braakmann-Folgmann Anne , Shepherd Andrew , Gerrish Laura , Izzard Jamie , Ridout Andy
Published: March 2022

Icebergs impact the physical and biological properties of the ocean along their drift trajectory by releasing cold fresh meltwater and nutrients. This facilitates sea ice formation, fosters biological production and influences the local ocean circulation. The intensity of the impact depends on the amount of meltwater. A68 was the sixth largest iceberg ever recorded in satellite observations, and hence had a significant potential to impact its environment. It calved from the Larsen-C Ice Shelf in July 2017, drifted through the Weddell and Scotia Sea and approached South Georgia at the end of 2020. Finally, it disintegrated near South Georgia in early 2021. Although this is a common trajectory for Antarctic icebergs, the sheer size of A68A elevates its potential to impact ecosystems around South Georgia through release of fresh water and nutrients, through blockage and through collision with the benthic habitat.

In this study we combine satellite imagery data from Sentinel 1, Sentinel 3 and MODIS and satellite altimetry from CryoSat-2 and ICESat-2 to chart changes in the A68A iceberg’s area, freeboard, thickness, volume and mass over its lifetime to assess its disintegration and melt rate in different environments. We find that A68A thinned from 235 ± 9 to 168 ± 10 m, on average, and lost 802 ± 35 Gt of ice in 3.5 years. While the majority of this loss is due to fragmentation into smaller icebergs, which do not melt instantly, 254 ± 17 billion tons are released through melting at the iceberg’s base - a lower bound estimate for the fresh water input into the ocean. Basal melting peaked at 7.2 ± 2.3 m/month in the Northern Scotia Sea. In the vicinity of South Georgia we estimate that 152 ± 61 Gt of freshwater were released over 96 days, potentially altering the local ocean properties, plankton occurrence and conditions for predators. The iceberg may also have scoured the sea floor briefly. Our detailed maps of the A68A iceberg thickness change will be useful to investigate the impact on the Larsen-C Ice Shelf, and for more detailed studies on the effects of meltwater and nutrients released off South Georgia. Our results could also help to model the disintegration of other large tabular icebergs that take a similar path and to include their impact in ocean models.
Nonlinear response of soil erosion to mean annual precipitation: evidence from erosion plot data in China
Authors: Zhao Jianlin
Published: March 2022

An extensive erosion plot database measuring soil loss and runoff under natural rainfall in China was compiled to gain new understanding of the overall response of the soil loss and runoff rate to land use, slope gradient, slope length and mean annual precipitation. Our results show that land use dominates the variation of soil loss and runoff: Soil loss and runoff rates on land covered by natural vegetation are one to three orders of magnitude lower in comparison to rates on agricultural land that is strongly disturbed by anthropogenic activities. Slope gradient and slope length affect soil loss and runoff rates on cropland but there is no statistically significant effect on either soil loss or runoff rate on permanent vegetation. This implies that different extrapolating relationships need to be used for cropland in comparison to land with permanent vegetation when erosion plot data are used to assess the erosion risk over large areas. Runoff rates consistently increase with mean annual precipitation. The relationship between soil loss and mean annual precipitation is different and is nonlinear for all land use types, with a clear increase of soil loss with precipitation up to a mean annual precipitation of ca. 700 mm yr-1, a subsequent decline and a second rise when the mean annual precipitation exceeds ca. 1400 mm yr-1. This non-linear response can be attributed to the interplay of an increasing rainfall erosivity and an increasing protection due to vegetation cover with increasing mean annual precipitation. It also implies that the effect of climate change on the erosion risk is not straightforward but depends on how both rainfall erosivity and vegetation cover change with changing climate.
Hydro-meteorological hazards and accidents at overhead power lines
Authors: Petrova Elena
Published: March 2022

The electric power industry is a key branch of the Russian economy, providing production, transmission, distribution, and consumption of electrical energy, thereby creating the basic conditions for the functioning of the entire economy of the country and the life support of its population. Overhead power lines are mostly exposed to the impacts of various natural hazards and phenomena, especially those of hydro-meteorological genesis. Accidents and emergency situations with power outages triggered by natural hazards and adverse phenomena account for more than a half in the total number of natural-technological accidents registered in the author’s database. The vulnerability of power transmission networks is caused by their large length, covering the entire economically developed territory of the Russian Federation. Throughout their course, power lines inevitably fall into the area of activation of hazardous natural processes and phenomena. The paper aims to reveal regional differences in the accident occurrences due to hazardous natural impacts on power transmission lines, identify principal hydrometeorological factors of these accidents, and find out regions most at risk. The methods used are the geographic and statistical analysis of the information collected by the author in an electronic database on technological and natural-technological accidents and emergency situations. The majority of natural-technological accidents with a power failure are caused by wind loads, which are especially dangerous in combination with other hydro-meteorological factors such as rain, snow, ice and frost deposit, thunderstorm, and hail.
NMR-spectroscopic virtual fractionation of soils mixed with pyrogenic carbon as a tool to separate chemical processes related to aging of pyrogenic carbon from those occurring during humification of soil organic matter 
Authors: Knicker Heike , Knicker Michael , García de Castro Barragán José María , Velasco-Molina Marta
Published: March 2022

Biochar has become an accepted soil amendment due to its potential to improve soil properties and as a tool to increase carbon sequestration. The latter is based on its relatively high biochemical recalcitrance augmenting the slow C pool after its addition to soils. However, newer studies indicated that the longevity of biochar and naturally produced pyrogenic organic matter (PyOM) in soils is lower than commonly assumed. Many of those studies are based on the determination of CO2 production changes or on the recovery of their isotopic labels in the soil after amendment of biochar or PyC incorporation. Most probably because of the lack of appropriate techniques to differentiate between the natural soil organic matter fraction and the added black carbon, only few reports are available which relate turn-over data with chemical alterations of biochar during aging or the impact of the latter on the quality of the total SOM pool.  In order to fill this gap, we applied virtual fractionation of SOM into different organic matter pools by different solid-state NMR techniques. Whereas the most common combines the determination of turnover rates via stable isotope techniques, an alternative approach takes advantage of different relaxation behavior of biochar and humified SOM. In both cases spectra can be calculated that show either the added biochar or the respective SOM.  In the frame of the present work, the concept and the potential of the two approaches will be explained by using examples studied in our laboratory.  With this, we intend to provide a further powerful tool which can lead to a better understanding of the biochemistry related to the transformation of PyC and biochar during aging and their subsequent integration into the soil organic matter fraction.

 

Acknowledgement: Financial support has been provided by the European Institute of Innovation and Technology (EIT), a body of the European Union, under Horizon2020, the EU Framework Programme for Research and Innovation (Project 21217 Black to the future - biochar and compost as soil amendment)
Applicability of aerial photography for identifying of oil mining technogenesis: mechanical transformations, bitumization, technogenic salinization
Authors: Sannikov Pavel , Khotyanovskaya Yuliya , Buzmakov Sergei
Published: March 2022

The main type of research material is multi-season aerial photography of the oil mining karst river basin was carried out by unmanned aerial vehicle.

Visual photo delineation revealed the consequences of mechanical transformations, some hydrocarbon inputs (bitumization) and salts (technogenic salinization) were also identified. The last processes were verified using materials from direct geochemical surveys (chemical analyses of soils, surface waters and sets of ordinary photo of sample plots).

It has been established that mechanical transformations, as a rule, is detected by the color and shape of objects. Less often, it is necessary to additionally analyze indirect photo delineation signs: shape of the shadow, configuration of the borders, traces of heavy vehicle tracks. Photo delineation signs of technogenic salinization are turbidity of water and the acquisition of a bluish-whitish color; the change of the color of the water body to green-yellow; white ground salt spots. The bituminization process is sufficiently reliably identified only in the presence of open oil spills on the surface of soil or water. Despite the difficulty of photo delineation, the use of orthophotos allows to identify 13 new sites (26 in total in the studied area) of the processes of bitumization and technogenic salinization, which had not been noted during previous large-scale field survey.

The use of orthophotos to detect the processes of bitumization and technogenic salinization is effective, especially in combination with direct field studies. Conditions for using aerial photography to identify the consequences of oil mining technogenesis: pixel resolution should be equals or more precise than 20 cm / pixel (more desirable – equals or more precise than 10 cm / pixel), snowless shooting season, lack or low level of cloud cover, relatively low forest cover percent. The spatial distribution of the identified areas of all types of technogenesis indicates a close relationship with the location of oil mining facilities.

A promising direction for the development of the research is associated with the use of multispectral imaging, the improvement of attend field surveys, as well as the expansion of the experience of aerial photography of oil fields located in other natural conditions.

The reported study was funded by Russian Foundation for Basic Research (RFBR) and Perm Territory, project number 20-45-596018.
Fine-Scale Characteristics of Summer Precipitation over Cang Mountain
Authors: Zhang Mengke , Li Jian , Li Nina
Published: March 2022

Fine-scale characteristics of summer precipitation over Cang Mountain, a long and narrow mountain with a quasi-north–south orientation in Southwest China, are studied using station and radar data. Three kinds of rainfall processes are classifified according to the initial stations of regional rainfall events (RREs) by utilizing minute-scale rain gauge data. RREs initiating in the western part of Cang Mountain exhibit eastward evolution and tend to reach their maximum rainfall intensity on the mountaintop. The results indicate differences in the precipitation evolution characteristics between short-duration (1–3 h) and long-duration (at least 6 h) events. Short-duration events begin farther from the mountaintop and then propagate eastward, whereas long-duration events remain longer around the mountaintop. RREs that initiate from the eastern part of Cang Mountain display westward propagation and frequently reach their maximum rainfall intensity over the eastern slope of the mountain. Among them, short-duration events tend to propagate farther west of Cang Mountain at high speeds, but the westward evolution of long-duration events is mainly confifined to the eastern part of Cang Mountain. For mountaintop-originated RREs, precipitation quickly reaches its maximum intensity after it starts and then continues for a long time around the mountaintop during the period from late afternoon to early morning. These fifindings provide references for the fifine-scale prediction of precipitation evolution in small-scale mountainous areas.
Electromagnetic energy conversion by various processes in turbulent plasmas observed by MMS
Authors: Aiamsai Thanapon , Pongkitiwanichakul Peera , Kieokaew Rungployphan , Ruffolo David , Pianpanit Theerasarn
Published: March 2022

A key issue in space plasma physics is how electromagnetic energy is converted to plasma particle energy and heat. Electromagnetic energy conversion generally involves turbulence and/or instabilities. With the Magnetospheric Multiscale (MMS) mission data, we investigate such energy conversion in turbulent plasmas, separating the plasma currents from various drift motions and other processes and assessing their contributions. For example, we have explored the roles of curvature drift, gradient drift, particle inertia drift and perpendicular magnetization currents. We will discuss their roles and related mechanisms in turbulent plasmas. This research has been supported in part by grant RTA6280002 from Thailand Science Research and Innovation, by DPST scholarship grant ,and by grant RGNS 63-045 from Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation.
Modality and seasonal variation of the tropical rain belt across climates and models
Authors: Adam Ori , Farnsworth Alexander , Lunt Daniel
Published: March 2022

The tropical rain belt is composed of rain bands that lie along the rising branches of the tropical atmospheric overturning circulation. The properties of these rain bands determine the zonal-mean tropical precipitation distribution, which varies between uni- and bimodality. Here we define tropical modality as an index that varies continuously between 1 and 2 for purely uni- and bimodal distributions. We examine the relation of tropical modality to the seasonal cycle of the tropical rain belt across a wide range of climate models from phases 5 and 6 of the climate model intercomparison project, simulations of Earth's climate over geological timescales (~300Ma to present), and observations. Our analysis shows that modality is an essential characteristic of tropical climate, which binds together fundamental properties of the tropical rain belt and its associated tropical overturning circulation. Specifically, tropical modality is found to efficiently parse differences across models and climates, especially in regions where variance is greatest. Increased tropical modality (i.e., tendency toward bimodality) is strongly related to increased width of the tropical rain belt, wider and weaker Hadley circulation, colder equatorial cold tongues, and more severe double-intertropical convergence zone bias in modern climate models. As tropical modality increases, considering shifts of hemispheric precipitation peaks becomes crucial. In particular, counter to general wisdom, for large tropical modality (i.e., ~2), seasonal migrations of the tropical rain belt do not follow the Hadley circulation paradigm, to the extent that hemispheric rain bands might not follow the Sun.
Data-driven reconstruction of the main traits of the large-scale Po River basin subsurface system
Authors: Manzoni Andrea , Riva Monica , Porta Giovanni , Guadagnini Alberto
Published: March 2022

We discuss the definition and implementation of an integrated groundwater and surface water flow modeling framework focused on the Po River basin (Italy; with an extension of about 72.000 km2). At such a scale, it is possible to characterize global (space‐time) patterns of groundwater response in a way that is typically overshadowed when considering analyses at the scale of a single aquifer. We create a georeferenced three-dimensional platform that unifies the diverse types of data available in the basin area. The data collected merge streams of information from a variety of sources, including, e.g., climate satellite data, soil properties and land use data, and lithological/sedimentological information. In this context, we consider two key inputs of the large-scale groundwater model: i) the estimation recharge rates and ii) the reconstruction of the subsurface architecture. We then focus on the latter element and analyze the most critical steps associated with data collection, organization, and interpretation. We obtain an operational model of the domain upon relying on lithological and sedimentological information to reconstruct the spatial distribution of subsurface geomaterials which we integrated within a machine learning approach based on Artificial Neural Networks. Results are compared with available geological interpretations in the area. We discuss feedbacks between (a) the characterization of the system, as driven by domain discretization, that aims at considering a high-resolution hydrogeological reconstruction and (b) computational efficiency. Our results are discussed in the framework of future developments of the study with a view to establishing a physically-based three-dimensional characterization of large-scale groundwater flow accounting for a variety of processes taking place across multiple scales.