bluuebunny/crossref_metadata_2025 huggingface dataset:
A regional approach for exploring the relation between sediment transport and coastal erosion in Sicily. 
Authors: Azzara Grazia , Manno Giorgio , Martinello Chiara , Lo Re Carlo , Mercurio Claudio , Basile Mirko , Ciraolo Giuseppe , Rotigliano Edoardo
Published: March 2022

To study on a regional basis, the relation between fluvial sediment delivery and coastal erosion, the historical record of coastline migration of Sicily was analyzed with respect to the estimated sediment delivery to the coast obtained from the spatially distributed sediment delivery WaTEM/SEDEM model. The latter was directly acquired from the ESDAC database as a 25 m pixel layers, being based on the combination between the RUSLE model and a transport capacity routing algorithm.

At the same time, the coastline-evolution (accretion/retreatment) data for 1960/1994 and 1994/2012 intervals were processed. This dataset, provided by ISPRA (Italian Institute for Environmental Protection and Research), is made by vectorial polygons, corresponding to erosion or accretion areas obtained by the intersection between two coastlines. The dataset contains polygons related to the 1960-1994 and 1994-2012 periods.

Once a common baseline was extracted from 2019 satellite images, 22 Physiographic Units (PU) were identified. The PU was defined based on geomorphologic criteria and by assuming a null net sediment budget (null sediment transport between two PU neighboring). Each coastal PU was connected to its contributing fluvial basins, also assigning the expected sediment delivery at the coastline.

To perform the analysis, cross profiles along the coastline were generated and intersected with the polygons, calculating a response value, in terms of retreatment or accretion, to each of the cross-profile centroids. Finally, for each PU, the cumulated variations were computed.

PUs with significant cumulative variations (more than 2 km) in at least one of the two epochs were identified and three different patterns were detected: accretion/retreatment, retreatment/accretion, and retreatment/retreatment. The response observed for the different PUs was then analyzed considering estimated sediment delivery, recognizing coherent (large sediment delivery = accretion) and incoherent (large sediment delivery = retreatment) behaviors, which have been interpreted as controlled by the history of soil/coastal erosion management practices.

In particular, in spite of a very high expected sediment delivery, more than three-quarters of the Tyrrhenian coast resulted as affected by a marked retreat in 60-94 (same tens of meters) and a moderate accretion in 94-12, as the result of extensive coastal works which have been realized to mitigate coastal erosion. 
Recent findings from Juno’s Stellar Reference Unit
Authors: Becker Heidi , Florence Meghan , Brennan Martin , Guillaume Alexandre , Hansen Candice , Ravine Michael , Bolton Scott , Arballo John , Alexander James
Published: March 2022

Juno enters its Extended Mission with its low-light sensitive Stellar Reference Unit (SRU) navigation camera poised to explore the Jovian system under novel illumination conditions. During the Prime Mission, high resolution SRU images of Jupiter’s dark side led to the discovery of “shallow lightning,” discharges originating from high altitude ammonia-water storms (above the 2 bar level) where it is too cold for liquid water to exist. Unique SRU images of Jupiter’s faint dust ring have been captured from rare vantage points, including from locations inside the ring looking out. And during Juno’s 34th orbit, the SRU acquired a high resolution (< 1 km/pixel), high illumination angle (>79 degrees) image of Ganymede’s dark side in a region of Xibalba Sulcus illuminated solely by Jupiter-shine. This softly lit image reveals numerous small craters and surface features which are unresolved in the prior Voyager imagery used in the USGS map. This presentation will highlight the recent science findings of Juno’s SRU.

 

The JPL authors’ copyright for this abstract is held by the California Institute of Technology. Government Sponsorship acknowledged.
The interplay between recycled and primordial heterogeneities: constraints on Earth mantle dynamics via numerical modeling
Authors: Desiderio Matteo , Gülcher Anna J. P. , Ballmer Maxim D.
Published: March 2022

A quantitative understanding of Earth's deep compositional structure remains elusive. Geophysical and geochemical observations illuminate heterogeneous features on various scales in the lower mantle: however, the origin and interaction of such heterogeneities are not yet fully explained in the context of global mantle dynamics. Conversely, numerical geodynamic models predict a wide range of viable scenarios of mantle convection and heterogeneity preservation. In the "marble cake" end-member mantle model, slabs of Recycled Oceanic Crust (ROC) are subducted and deformed but never fully homogenized in the convecting mantle. In the "plum pudding" model, MgSiO3-rich primordial material may resist convective entrainment due to its intrinsic strength. Only few geodynamic studies have explored the effects of subducted ROC properties on mantle dynamics while also accounting for the influence of primordial heterogeneity. Furthermore, predictions from numerical models need to be tested against geophysical data. However, current imaging techniques poorly resolve the lower mantle and may be unable to distinguish between both end-member models above.

Here, we use the finite-volume code StagYY to model mantle convection in a 2D spherical-annulus geometry. We investigate the style of heterogeneity preservation as a function of two parameters: the intrinsic density and the intrinsic strength (viscosity) of basalt at lower-mantle conditions.  Additionally, we employ the thermodynamic code Perple_X and the spectral-element code AxiSEM to compute, respectively, seismic velocities and synthetic seismograms from the predictions of our models.

We obtain two main regimes of mantle convection: low-density basalt leads to a well-mixed, "marble cake"-like mantle, while dense basalt aids the preservation of primordial blobs at mid-mantle depths as in a "plum pudding". Intrinsically viscous basalt also promotes the preservation of primordial material. These trends are well explained by smaller convective vigour of the mantle as intrinsically dense (and viscous) piles of basalt shield the core. In order to test these model predictions, we convert model temperatures and compositions to thermoelastic properties for two characteristic models of each regime. These are then used to compute synthetic seismic velocity models, through which we simulate wave propagation using AxiSEM. Finally, we  discriminate between these two end-members by comparing statistical properties of the corresponding ensembles of synthetic seismograms. Our results highlight how the interaction of mantle materials drives the long-term thermochemical evolution of terrestrial planets. Furthermore, they provide a framework for relating the style of heterogeneity preservation in the Earth's lower mantle with specific features of the seismic waveforms.
Activity concentration of radionuclides of natural and anthropogenic-transformed soils in Rostov region
Authors: Kozyrev Denis , Gorbov Sergey , Buraeva Elena , Salnik Nadezhda
Published: March 2022

Topsoil is a filter that can absorb all wastes of production and anthropogenic activities. During the last 35 years, following several large industrial disasters and artificial radionuclides entering ecosystems, the ways of their migration and impact on living and biosphere systems are attracting close attention. As a result, the determination of both artificial and natural radionuclides in the soil seems relevant and is part of the radiation monitoring of the soil cover in Russia and the world. The purpose of the work was to carry out ecological monitoring of park-recreational, residential areas, as well as specially protected natural areas of the South of European Russia.

 

The maximum average value of activity for the artificial radionuclide 137Cs was revealed in the soils of specially protected natural territories, there is a maximum variation of values. Significant variation of the obtained activity results relates to large sampling and wide geography of studied objects and proximity to the place of the Chernobyl accident (April 26, 1986). Specific activity of natural radionuclides is at the level of average values typical for the Rostov region, which are confirmed by the previously conducted data. The specific activity in recreational areas and specially protected natural territories is approximately at the same level and has a similar distribution pattern. The arithmetic average of specific activity of the studied radionuclides for the inhabited zones is:137Cs - 13,5 ± 1,3 Bq/kg, 226Ra - 19,0 ± 1,1 Bq/kg, 232Th - 20,6 ± 0,8 Bq/kg, 334 ± 13,3 Bq/kg - 40K; for recreational:15,8 ± 0,9  Bq/kg - 137Cs, 226Ra – 24,0 ± 0,4 Bq/kg, 232Th – 31,5 ± 0,4 Bq/kg, 436 ± 6 Bq/kg - 40K and for specially protected natural areas: 25,6 ± 3,6 Bq/kg - 137Cs, 226Ra – 23,8 ± 0,7 Bq/kg, 232Th – 26,4 ± 0,8 Bq/kg, 365,8 ± 13,1 Bq/kg - 40K.

This study  was performed with financially supported by the Ministry of Science and Higher Education of the Russian Federation within the framework of the state task in the field of scientific activity (no. 0852-2020-0029)
The transition from practical to intrinsic predictability of midlatitude weather
Authors: Selz Tobias , Riemer Michael , Craig George
Published: March 2022

In this study the transition from current practical predictability of midlatitude weather to its intrinsic limit is investigated. For this purpose, estimates of the current initial condition uncertainty of 12 real cases are reduced in several steps from 100% to 0.1% and propagated in time with a numerical weather prediction model (ICON at 40km resolution) that includes a stochastic convection scheme. It is found that the potential forecast improvement through initial condition perfection is 4-5 days, which can essentially be achieved with an initial condition uncertainty reduction by 90% relative to current conditions. With respect to physical processes, this reduction of the initial condition uncertainty is accompanied with a transition from rotationally-driven initial error growth to error growth dominated by latent heat release in convection and due to the divergent component of the flow. With respect to spatial scales, a transition from large-scale up-magnitude error growth to upscale error growth and an acceleration of the initial growth rate is found. Reference experiments with a deterministic convection scheme show a 5-10% longer predictability interval, but only if the initial condition uncertainty is small. These results confirm that planetary-scale predictability is intrinsically limited by latent heat release in clouds through an upscale-interaction process, while this process is unimportant on average for current amplitudes of the initial condition uncertainty.
Isotopic age and geochemical features of the porphyry Cu-Mo ore-forming systems of the Magadan mineragenic area (North-Eastern part of Russia)
Authors: Alenicheva Antonina , Kolova Elena , Kasatkin Nikita
Published: March 2022

In the present study, we carried out molybdenite Re-Os, zircon U-Pb dating on granitoids from the insufficiently explored Cu-Mo and Mo porphyry deposites and ore occurrences (Osennee, Oksinskoe, Uptar, Doroninskoe) of the Magadan region. The ore-age of these porphyry objects is confirmed by Re-Os dating of molybdenite and corresponds to the age of the ore-forming granitoids.

Intrusive complexes (Svetlinsky and Magadansky), which related to Mo mineralization, have a variable SiO2 content of 61-74 %, and K2O Na2O content of 5,4-6,9%. They are calc-alkaline series (K2O/Na2O ratio of 0,6-0,8) I type granitoids. They are depleted high-field-strength elements Nb and Ta (HFSE) and enriched Rb, Sr, Hf (LILEs). On the Sr/Y – Y variation diagram, most of the granitoids are located in the field of «adakite» igneous rocks of porphyry deposits.

The U-Pb age of granite zircons was determined by the SHRIMP method and showed two pulses of Albian-Cenomanian magmatic activity– a 93-95 Ma (Svetlinsky complex) and a 102-103 Ma (Magadansky complex). The isochronous molybdenum Re-Os age 99-100 Ma and 92-94 Ma from Doroninsky Mo-porphyry stock and from Osennee and Usinskoe Cu-Mo ore occurrences confirms the genetic relationship of granites and Mo mineralization. There is a little age gap between granite cristallisation and ore formation. Mo mineralization probadly was formed later by 1-2 Ma from the magmatism responsible intrusion. The isotopes Re and Os are used to determine the origin of the source of porphyry mineralization metals. High Re contents (>33 ppm) in studied molybdenite indicates mantles course of metall in deposites Magadan mineragenic area. The mantle source is indicated by low non-radiogenic ratios of 187Os/188Os (0.32-0.21) in molybdenite of the Usinskoe ore occurrences. A more radiogenic osmium (187Os/188Os =1-15) was obtained for the Osennee ore occurrence.

New precision geochronological data on the Albian-Cenomanian age of Cu-Mo mineralization allow us to conclude about geodynamic environments that controlled ore formation. Obviously, mineralization in Magadan mineragenic area spatially and temporally related with Albian-Cenomanian igneous rocks and have identical sourses. Ore-forming granitoids are part of the Albian-Cenomanian orogenic magmatic belt, which occurred in a sliding plate boundaries environment on the border of the Eurasian continent margin and the Palaeo-Pacific Ocean (Khanchuk, 2019).
Tsunami Ionospheric Monitoring Across the Pacific Ocean and the Southern Atlantic
Authors: Munaibari Edhah , Rolland Lucie , Sladen Anthony , Delouis Bertrand
Published: March 2022

As tsunamis propagate across open oceans, they remain largely unseen due to the lack of
adequate sensors. To help better mitigate the tsunami risk, we use a detection method that takes
advantage of the efficient coupling of tsunami waves with the atmosphere. Tsunami-induced
internal gravity waves thus travel upward in the atmosphere, where amplitude amplifies by several
orders of magnitude as the air density decreases with altitude. Once the waves reach the
ionosphere, they put charged particles into motion, creating propagative phenomena known as
Traveling Ionospheric Disturbances (TIDs). Thanks to the Global Navigation Satellites Systems
(GNSS), such disturbances can be monitored and observed using the Total Electron Content (TEC)
derived from the delay that the ionosphere imposes in the electromagnetic signals transmitted to
the Earth’s surface by the GNSS satellites. Here we show ionospheric TEC signatures following the
passage of three ocean-wide tsunami events: the two tsunamis triggered by the March 4th, 2021
8.1 Mw Kermadec Islands, New Zealand, and the July 29th, 2021 8.2 Mw Perryville, Alaska
earthquakes, as well as across the southern Atlantic following the tsunami generated by the
August 12th, 2021 8.1 Mw Sandwich Islands earthquake. We classify the observed TEC signatures
based on detection reliability and the potential connection to the tsunami wavefield. In addition,
we utilize an analytical model to investigate the source of these identified TEC signatures. Thus, we
ensure their gravity-waves origin and assess the characteristics (wavelength, period, etc.) of such
gravity waves, which is necessary to confirm they originate from the tsunami. Finally, to better
map the tsunami amplitude at the ocean level in various configurations, we examine, compare,
and contrast the amplitude of the identified tsunami-induced TEC signatures from geographically
sparse regions. We account for multiple parameters such as the local magnetic field, the azimuth,
and the distance to the tsunami source. They all affect the TEC signature detection and the
retrieval of the tsunami wavefield and, thus, potentially, the estimated risk.
HDAS (High-Fidelity Distributed Acoustic Sensing) as a monitoring tool during 2021 Cumbre Vieja eruption
Authors: Barrancos José , D'Auria Luca , Padilla Germán , Preciado-Garbayo Javier , Pérez Nemesio M.
Published: March 2022

La Palma is the second youngest and westernmost among Canary Island. Cumbre Vieja volcano formed in the last stage of the geological evolution of the island and had suffered eight volcanic eruptions over the previous 500 years. In 2017, two remarkable seismic swarms interrupted a seismic silence from the last eruption (Teneguía, 1971). Since then, nine additional seismic swarms have occurred at Cumbre Vieja volcano. On September 11th, 2021, seismic activity began to increase, and the depths of the earthquakes showed an upward migration. Finally, on September 19th, the eruption started after just a week of precursors.

During recent years, the seismic activity has been recorded by Red Sísmica Canaria (C7), composed of 6 seismic broadband stations, which was reinforced during the eruption by five additional broadband stations, three accelerometers and a seismic array consisting of 10 broadband stations.

Furthermore, as a result of a collaboration between INVOLCAN, ITER, CANALINK and Aragón Photonics Labs, it was possible to install, on October 19th, an HDAS (High-fidelity Distributed Acoustic Sensor). The HDAS was installed about 10 km from the eruptive vent and was connected to a submarine fibre optic cable directed toward Tenerife Island. Since then, the HDAS has been recording seismic with a temporal sampling rate of 100 Hz and a spatial sampling rate of 10m for a total length of 50 km using Raman Amplification. For more than two months, in addition to the intense volcanic tremor, the HDAS recorded thousands of earthquakes as well as regional and teleseismic events. On December 13th, 2021, after an intense paroxysmal phase with an eruptive column that reached 8 km in height, the volcanic tremor quickly decreased, and the eruption suddenly stopped. Only a weak volcano-tectonic seismicity and small amplitude long-period events were recorded in the next month.

This valuable dataset will provide a milestone for the development of techniques aimed at using DAS as a real-time volcano monitoring tool and studying the internal structure of active volcanoes.
Unraveling the Origin of Rainfall over Horn of Africa Drylands
Authors: Koppa Akash , Keune Jessica , MacLeod David A. , Singer Michael , Miralles Diego G.
Published: March 2022

The Horn of Africa drylands (HAD) are highly vulnerable to hydroclimatic extremes, with droughts and floods frequently leading to famines, crop losses, and significant humanitarian crises. However, development of robust mitigation measures has been hindered by the lack of understanding of the drivers of the two main rainfall seasons in the region: the long (March–May) and short (October–December) rains. In particular, the inter-annual variability of the long rains has been subject of much debate; a significant amount of research has attempted to diagnose the drivers of the observed decline in the long rains. Given the ecological and socio-economic importance of the two rain seasons for the HAD region, understanding the major moisture sources and their variability in both space and time is essential. Such an analysis can help disentangle the causes of temporal variability in rainfall, especially the long rains, improve forecasts, and build ecosystem and community resilience against hydroclimatic extremes.

To trace the origin of rainfall over the HAD region, we use global simulations of the FLEXPART version 9.01, forced with the ERA-Interim reanalysis for a period of 37 years (1980–2016). The FLEXPART outputs include the properties of the air parcels at 3-hourly time steps, which are then post-processed to identify the source regions of rainfall using the Heat and Moisture Tracking Framework (HAMSTER v1.2.0) described by Keune et al. (2021). Using this framework, we first trace the rainfall occurring over the HAD region during the long and short rain seasons to their terrestrial and oceanic sources spatially. Then, we track the changes in the contributions of ocean and land evaporation to HAD rainfall in time over the 37-year period. 

Preliminary results show that around 80% of HAD rainfall originates from Indian Ocean evaporation, for both seasons. For both seasons the contribution of evaporation from land is relatively low compared to the oceanic contribution. For the long rains, a similar amount of moisture originates from recycling (local) and remote sources (10.9% and 10.5% respectively). On the other hand the short rains show a larger proportion of local recycling (13.8%) relative to remote land evaporation (9.4%). The larger contribution of remote land sources for the long rains arises from the Indian subcontinent and Southeast Asia. Further, we shed light on the trends and anomalies in source regions for the two rain seasons, with particular focus on the anomalies in moisture sources that are characteristic of extreme dry and wet conditions.

References:

Keune, J., Schumacher, D. L., and Miralles, D. G.: A holistic framework to estimate the origins of atmospheric moisture and heat using a Lagrangian model, Geosci. Model Dev. Discuss. [preprint], in review, 2021.
The diurnal cycle resonates with the large-scale circulation
Authors: Haerter Jan O. , Fiévet Romain
Published: March 2022

Tropical deep convection is both driven by the large-scale circulation, such as the Hadley Cell, as well as by periodic heating, namely the diurnal cycle. In a suite of idealized cloud-resolving simulations we allow for an idealized Hadley Cell to evolve by imposing a spatial surface temperature gradient. In line with recent studies (O’Neill et al., 2017, Patrizio & Randall, 2019), we find that a large-scale oscillation of period TL self-organizes, visible in many quantities, especially precipitation. The period TL is found to depend approximately linearly on L, the meridional domain size. When we now impose a diurnal cycle at TD=1day, the timeseries of precipitation is modified. For small L, the power spectrum shows that TD dominates, whereas for large L the intrinsic mode TL prevails. At intermediate TL⋍TD a resonance occurs, which causes the amplitude to nearly double, leading to more extreme rainfall. To gain insight, we propose a simple damped harmonic oscillator model with a spatial energy source, mimicking convective latent heat release. We associate the “spring constant” with the meridional domain size L. The coupling to the diurnal cycle is then incorporated by a periodic drive. Results show that the model can mimic the resonance at intermediate periods and the dominance of large-scale modes at large system sizes. We further find an envelope period which may give insight into the observed meandering of the ITCZ (Mapes et al., 2018). Our results could help understanding of tropical extreme events, e.g. MCS, and how they could be invigorated by the large scale circulation.
Delayed lithosphere tearing along STEP Faults 
Authors: Broerse Taco , Govers Rob , Willingshofer Ernst
Published: March 2022

Tearing of the lithosphere at the lateral end of a subduction zone is a consequence of ongoing subduction. The location of active lithospheric tearing is known as a Subduction-Transform-Edge-Propagator (STEP). The transcurrent plate boundary system lengthens with time and is referred to as the STEP Fault. Lithospheric tearing was taken to start at the trench in the classical STEP model of Govers and Wortel (2005). They show that active STEPs and STEP Faults can be found alongside many subduction zones. However, recent seismicity studies show results near the active STEPs that are difficult to reconcile with the classical STEP model: there is significant and deep seismicity along the STEP Fault near to the west of Trinidad in the southeast Caribbean; a Wadati-Benioff zone perpendicular to the Pliny-Strabo trenches (the STEP Fault) in the eastern Mediterranean reaches 180 km depth; STEP Fault perpendicular earthquake slip vectors are observed along the northern termination of the South Sandwich trench. We seek to understand these discrepancies by studying the tearing process.  

We show results of new physical analog lab models that aim to elucidate what controls lithospheric tearing and the resulting geometry of the lithospheric STEP. We study the ductile tearing in the process of STEP evolution, which is dynamically driven by the buoyancy of the subducting slab. In our experiments, the lithosphere as well as asthenosphere are viscoelastic media in a free subduction setup. A stress-dependent rheology plays a major role in localization of strain in tearing processes of lithosphere such as slab break-off. 

We find that complete tearing of the lithosphere typically occurs later than in the classical model, at 100-150 km depth. The slab is consequently highly curved near the lateral end of the trench. However, not all STEPs show evidence for such delay, e.g., the north end of the Tonga trench. In our model experiments we therefore investigate the influence of age and integrated strength of the lithosphere and its contrasts across the passive margin, on the timing, depth, and the degree of localization of the tearing process. Furthermore, we relate the tearing at depth to deformation at the surface along and across the STEP fault and we discuss potential consequences for STEP evolution for a number of subduction zones worldwide. Delayed lithospheric tearing explains the observations qualitatively. 
Countermeasures against flood in the Chao Phraya River Basin, Thailand - Assessment and adaptation to combat climate change 
Authors: Padiyedath Gopalan Saritha , Hanasaki Naota
Published: March 2022

The countries of Southeast Asia are projected to experience severe flood damage and economic impacts from climate change, compared with the global average. Thailand is the second-largest economy in Southeast Asia and future flood damage is likely to hinder the economic growth of Thailand because Bangkok City (the commercial hub of the country) is located in the Chao Phraya River delta, where floods are frequent. Despite this fact, thus far, comparatively little research has been conducted to investigate the combined effects of climate change, human activities, and adaptation measures on flood risk reduction in the Chao Phraya River Basin (CPRB). Therefore, this study was conducted in the CPRB to examine the adaptation potential of (i) existing structural and non-structural measures that include reservoir and diversion dams, diversion canals, and water retention areas, and (ii) a combination of alterations made to the existing diversion canals and retention areas (combined adaptation) on reducing future floods using the H08 global hydrological model.

Future flood risk was analyzed using various flood risk indicators including flood frequency, number of flooding days, and annual maximum daily discharge. The results revealed that the impact of existing measures on the future flood reduction was smaller than the increase caused by warming in the upper and lower CPRB. Although the combined adaptation measures had considerable potential to reduce the magnitude and duration of future floods in the CPRB, extreme floods may continue to occur in the basin and further strategies are needed to alleviate the flood risk. Our findings emphasize that the integration of various existing structural and non-structural measures along with adaptation measures will be insufficient to completely mitigate future flood risk in the CPRB although the considered measures can greatly reduce future flooding. This study highlights the areas of the CPRB that are vulnerable to extreme flooding in the future and thus require area-based prioritization for flood management. Moreover, this study clearly indicated that GHMs can be effectively implemented for the design of regional adaptation measures.
Kinetic generation of whistler waves in the turbulent magnetosheath
Authors: Svenningsson Ida , Yordanova Emiliya , Khotyaintsev Yuri , André Mats , Cozzani Giulia
Published: March 2022

Whistler waves, right-hand polarized waves with frequencies below the electron cyclotron frequency, are common in many space plasma regions such as the Earth’s magnetosheath. They can be generated by electron temperature anisotropy, in which case the instability grows through cyclotron resonance. A common way to determine the stability of an electron distribution function is to compare the parallel and perpendicular temperature (with respect to the background magnetic field) to stability thresholds. However, such an approach based on the moments of the distribution function can potentially leave out some properties of the distribution which are important for wave generation.

In this work, we investigate the features of the electron distribution functions measured by MMS in the turbulent magnetosheath downstream of a quasi-parallel shock. We show that even though statistically whistler waves tend to occur close to the regions where the stability threshold is exceeded, they are also observed in regions predicted to be stable to wave generation. For such waves we observe that the electron pitch angle distribution often has the so-called butterfly shape (with minima in both the parallel and perpendicular directions) and is located in magnetic field minima. Using a linear numerical dispersion solver (WHAMP), we show that the butterfly distribution is unstable to whistler wave generation even though the instability threshold based on the associated moments is not exceeded. Comparison between the numerical results and waves measured by the MMS spacecraft indicate that the observed whistler waves are generated by the butterfly distribution. This phenomenon has previously been observed in mirror modes and large scale magnetic holes. Our findings show that it also occurs on smaller scales (~1 ion inertial length) in more turbulent environments, such as the quasi-parallel magnetosheath.
Spatial and temporal analysis of deep convection activity over Tibetan plateau and the Himalayan Mountain region.
Authors: Singh Prashant , Ahrens Bodo
Published: March 2022

We investigate the deep convection activity over the Himalayan Mountain (HM) and Tibetan Plateau (TP) using long-term lightning and precipitation data sets.  The observational data suggest that lightning activity during the months of May & June is greater in comparison with the rest of the year. Since lightning events are treated as a signature of deep convection, those periods can be classified as deep convective periods. In addition, Easter HM shows high deep convection activity during March-April and Western HM during September-October. The Southern TP faces maximum disturbance during June-August mainly during afternoon hours 12:00-16:00 Local Time (LT). Whereas over Eastern and Western HM region peak hours are between 22:00-04:00 LT and 15:00-20:00 LT, and Central HM peaks are between 14:00-19:00 LT. We further report the relation between changing planetary boundary layer (PBL) and water vapor (WV) transport during deep convection events at seasonal and diurnal scales over TP and HM.
Modelling increasing natural-hazard risk due to urban growth in Kathmandu Valley, Nepal
Authors: Mesta Carlos , Cremen Gemma , Galasso Carmine
Published: March 2022

In our rapidly urbanizing world, many hazard-prone regions face significant challenges when it comes to risk-informed urban development. This study specifically addresses this issue by investigating evolving spatial interactions between natural hazards, ever-increasing urban areas, and social vulnerability in Kathmandu Valley, Nepal. The methodology used in this work considers: (1) the characterization of flood hazard and liquefaction susceptibility using pre-existing global models; (2) the simulation of future urban built-up areas using the cellular-automata SLEUTH (Slope, Land use, Excluded areas, Urban extent, Transportation, Hillshade) model, which requires satellite imagery for statistical calibration and validation; and (3) the assessment of social vulnerability using a social vulnerability index tailored for the case-study area. Results show that the total built-up area in Kathmandu will increase to 352 km2 by 2050, which is effectively double the equivalent 2018 figure of 177 km2. The most socially vulnerable villages will account for 29% of the total built-up area in 2050, which is 11% more than their current proportion. Built-up areas in the 100-year and 1000-year return period floodplains will respectively increase from 38 km2 and 49 km2 today to 83 km2 and 108 km2in 2050. In the same time frame, built-up areas in liquefaction-susceptible zones will expand by  13 km2 to 47 km2. The results of this study illustrate how, where, and to which extent risks from natural hazards can evolve in socially vulnerable regions. Ultimately, this study emphasizes an urgent need to implement effective policy measures (e.g., land-use regulations) for reducing tomorrow's natural-hazard risks.
Landslide investigation using Remote Sensing and Geophysics
Authors: Gautier Stéphanie , Wanner Xavier , Fabre Juliette , Besso Romain , Vidal Maurin , Ottiwitz David , Jochum Birgit , Lajaunie Myriam , Bertrand Catherine , Malet Jean-Philippe
Published: March 2022

Over the last decade, many Electrical Resistivity Tomography (ERT) surveys have been acquired on landslides, both from surface and boreholes. The surveys aimed at inferring the geometry of the landslide body, at imaging conductive and resistive structures possibly linked to in-depth water storage, and even at qualifying underground water flows. Several ERT galvanic-type configurations have been deployed according to the sites, all of them using buried metallic electrodes as conductors. Devices were deployed both on hard rocks (mostly crystalline) and soft rock (mostly clayey) landslides, and most were associated with hydrogeological observations (soil temperature, groundwater table, soil humidity). 
The acquired time-lapse resistivity profiles represent real added-value information for the long-term understanding of landslide processes and their links to meteorological and hydrological triggering factors. In France, most of the ERT surveys on landslides were acquired by the French Landslide Observatory (OMIV) of the Institute of Earth and Universe Science (INSU), in collaboration with many Universities (Strasbourg, Nice, Montpellier) and with the Geological Survey of Austria (Vienna). 
The electrical resistivity datasets are acquired either individually on particular dates with possible repeated measurements or at high-frequency with fixed and automated measurement devices and permanent arrays. At the surface, multi-electrode ERT surveys are recorded by SYSCAL Pro (Iris Instrument) or GEOMON4D resistivimeters (GSA / Supper et al., 2002). Using the GEOMON4D device, at least 2 measurements of resistance are performed daily (using multiple gradient array). The SYSCAL resistivity surveys are measured every day using a Wenner-Schlumberger array. In boreholes, dipole-dipole electrical soundings are recorded daily using an autonomous acquisition system (ImaGeau®) with inter-electrode spacings of one meter. 
The objective of this work is to present the OMIV-ERT free online repository of electrical resistivity data. Data are provided at three interpretational levels: (i) raw data (Vn and In, level 0), (ii) filtered and computed apparent resistivity (level 1), and (iii) inverted data (resistivity model, level 2). The information system consists of a PostgreSQL/PostGIS spatial database, R and Python scripts for data pre-processing and integration in the database. The pyGIMLi (Rücker et al., 2017) library is interfaced with R scripts to invert the resistivity data (from level 1 to level 2). An R-shiny-based web interface for data visualization and download is accessible online. The OMIV-ERT database will permit analyses of relationships between measured resistivities and landslide conditions.
Airborne measurement of ship emissions in international waters and Sulphur Emission Control Area
Authors: Pasternak Dominika , Lee James , Hopkins James , Bauguitte Stéphane , Batten Stephanie , Yang Ming-Xi , Bell Thomas , Coe Hugh , Bower Keith , Andrews Stephen , Temple Loren , Vallow Jake , Matthews Emily , Bannan Thomas , Marsden Nicholas , Wu Huihui , Thamban Navaneeth
Published: March 2022

1 January 2020 marked a major change in the legal sulphur content of shipping fuel – from 3.5% to 0.5% by mass outside of the Sulphur Emission Control Areas (SECAs). The anticipated effect of the new regulation is improvement of coastal air quality, supporting both environmental and human health. In addition, since sulphur is believed to be a negative climate forcer, removal of its substantial source might have positive influence on the global climate.
The Atmospheric Composition and Radiative forcing changes due to UN International Ship Emissions regulations (ACRUISE) project demonstrates the use of a large aircraft to measure emissions from ships and their impact on local air quality and cloud formation. The Facility for Airborne Atmospheric Measurements (FAAM) research aircraft was deployed first in July 2019 (before regulation change) in shipping lanes along the Portuguese coast, the English Channel SECA and the Celtic Sea. Over 100 ships were sampled, 15 specifically targeted for plume aging and cloud interaction. A large container ship showed significant reduction in apparent fuel sulphur content upon entering SECA. Bulk statistics in and out of extremely busy shipping lanes were collected. The second, post regulation change, part of the fieldwork was postponed by the COVID-19 pandemic until September 2021. Over 150 ships were measured in the shipping lanes of the Bay of Biscay, the English Channel SECA and Celtic Sea. This part of the work focussed more on targeting specific ships, than on bulk measurements due to lower density of ships in the region and improved sampling strategy.
This study presents a range of aspects of measurements. Onboard measurements of SO2, CO2, CH4 and speciated PM provide emission factors and apparent fuel sulphur content for a variety of ships. Moreover, about 100 whole air samples were taken during each fieldwork and analysed for VOCs. The encountered vessels included container ships, bulk carriers, cruise ships, ferries, crude oil tankers and even elusive LNG tankers. Some ships were measured both in and out of SECA and a few ships were measured both in 2019 and 2021. 
Xylem hydraulic conductivity measurements during flow-controlled experiments suggest the presence of nanobubbles that move with the flow and accumulate at vessel ends
Authors: Krieger Louis , Schymanski Stanislaus , Jansen Steven
Published: March 2022

Commonly, xylem hydraulic conductance is measured by applying a positive pressure (above atmospheric) to push water through a twig. To imitate flow in twig samples under natural conditions, we developed a method that applies a controlled flow rate using suction, similar to transpiration-driven flow in plants.

The setup consists of a syringe pump to control water flow, where a twig is inserted in the flow path and hydraulic conductivity is calculated from measurements using pressure sensors and a flow meter. The syringe pump can be used to generate controlled flow rates in both directions and a series of bypasses can be used to self-calibrate the sensors and reverse flow directions through the twig while the syringe pump is either pushing or pulling. In this way, we were able to compare our suction method with the more conventional pushing method and assess the effect of flow direction on hydraulic conductance measurements. We found a reproducible pattern in measured conductivity values, where measurements using suction resulted in a 50% lower conductivity than when flow was induced by pushing. The direction of flow (root-shoot vs. shoot-root) also had a strong influence, with suction in root-shoot direction resulting in the lowest conductivity measurements, but repeated reversals of flow revealed an intricate pattern of loss and partial restoration of conductivity, implicating the existence of particles that move with the flow and accumulate at the vessel ends.

Here we present the intriguing results and propose an explanation capable of explaining the reproducible patterns in observed conductivity dynamics during the experiments. The explanation involves nanobubbles that shrink and swell depending on the liquid pressure and surface tension, move with the flow and reduce conductivity as they accumulate at vessel ends.
Oxygen isotopes in Amazon tree rings as indicators of change in the hydrological cycle 
Authors: BRienen Roel , Cintra Bruno , Baker Jessica , Gloor Emanuel , Schöngart Jochen , Boom Arnoud , Helle Gerhard , Leng Melanie
Published: March 2022

The Amazon is the largest catchment in the world, discharging ca. 17% of global freshwater, and plays an important role in the global water and carbon cycles. Recent decades have seen an increase in floods of the Amazon river, but also increases in dry season severity and length. Instrumental long-term climate data to assess the magnitude of these changes are relatively scarce. Tree-ring based climate reconstructions may help improving past climate records from this vast region and put these changes in historical perspective.

While standard tree ring widths chronologies in the tropics are generally weakly related to climate, tree ring d18O records from Cedrela odorata in Bolivia are a proven proxy for Amazon basin-wide rainfall, and thus Amazon river discharge. However, these “terra firme” trees grow during the wet season and thus do not provide information on the dry season. Here we present a new proxy for dry season precipitation from Amazonian floodplain trees of Macrolobium acaciifolium from the western Amazon. As this species grows during the non-flooded period, the dry season, their tree ring d18O records should pertain variation of dry season precipitation d18O. A comparions of tree ring d18O from floodplain and terra firme trees show opposing trends since the 1970s, indicating increases in wet season precipitation and decreases in dry season precipitation. These records are consistent with recent trends in peaks and troughs of Amazon river levels, and provide support of a recent intensification of the Amazon hydrological cycle. We conclude that tree-ring d18O records are an important tool for tropical climate reconstructions, and even allow climate reconstructions with seasonal resolution. In addition, as signals arise from variation in (meteorological) precipitation d18O, tree ring d18O chronologies do not need detrending, and show highly synchronized patterns even over very large scales, allowing rigorous cross-dating between species and sites, and facilitating further development in this vast region
A new experimental method to predict the dispersion of Elongated Mineral Particles in the environment
Authors: Gomiero Cecilia , Barale Luca , Giustetto Roberto , Pacella Alessandro , Piana Fabrizio , Campopiano Antonella , Turci Francesco , Petriglieri Jasmine Rita
Published: March 2022

The occurrence of asbestos and asbestos-like minerals in natural sites may pose a risk to human health and the environment when rocks and soils are mobilized. Weathering and anthropic activities favour the liberation of potentially hazardous Elongated Mineral Particles (EMP, NIOSH 2011). The definition of EMP includes both asbestos and other fibrous minerals. The latter share several physical-chemical properties with asbestos, but their toxicological profile is still unknown. The assessment of risk requires the quantification of the occurrence and the estimation of the potential emissivity of EMP from the hosting matrix.

We quantitatively described the potency of a rock to disperse EMPs in the environment with a quantitative parameter namely the “liberability factor” (Lf). Lf was measured for 40 meta-ophiolite fragments from the NOA-bearing units of Liguria (Voltri Group and Sestri-Voltaggio Zone) and Calabria (Gimigliano-Monte Reventino Unit, Southern Ligurian Domain). The mineral–petrographic characterization of these rocks showed the presence of veins of chrysotile, fibrous tremolite-actinolite, fibrous sepiolite and fibrous antigorite.

By adapting the UNI EN 12457-2:2004 method for solid waste, we designed a weathering simulation test to quantify the EMPs and the fibres (according to the World Health Organization) possibly liberated by applying to the rock a standardized mechanical stress. Waterborne EMPs were filtered on membranes and counted by electron microscopy (SEM-EDS), by adapting the Italian Regional Agency for the Protection of the Environment (ARPA) procedure for waterborne asbestos (ARPA Piemonte, 2016). We obtained Lf values as the number of waterborne fibres suspended per unit volume of water (fibres/Litre). All analysed rock samples showed Lf values ranging from 30 Mf/L to 21’000 Mf/L. Chrysotile, tremolite, sepiolite, and antigorite, with asbestos-like habit, were detected.

Lf proved to be a reliable, easy to use method for the characterization and prediction of EMP and fibre dispersion in the environment from NOA-bearing rocks subjected to a standardized mechanical stress. This study is part of the BRIC 2019 project (grant number ID 57.1) supported by INAIL (Italian National Institute for Insurance against Accidents at Work).

 

References

ARPA Piemonte 2016. U.RP. M842 rev.03. Asbestos in water by Scanning Electron Microscopy.

NIOSH, 2011. Asbestos fibers and other elongate mineral particles. Current Intelligence Bulletin 62.

WHO, 1997. Determination of Airborne Fibre Number Concentrations. ISBN 92 4 154496 1
The Response of the Large-Scale Tropical Circulation to Warming
Authors: Silvers Levi , Reed Kevin , Wing Allison
Published: March 2022

Previous work has found that as the surface warms the large-scale tropical circulations weaken, convective anvil cloud fraction decreases, and atmospheric static stability increases. Circulation changes inevitably lead to changes in the humidity and cloud fields which influence the surface energetics.  The exchange of mass between the boundary layer and the midtroposphere has also been shown to weaken in global climate models.    What has remained less clear is how robust these changes in the circulation are to different representations of convection, clouds, and microphysics in numerical models.  We use simulations from the Radiative‐Convective Equilibrium Model Intercomparison Project (RCEMIP) to investigate the interaction between overturning circulations, surface temperature, and atmospheric moisture.  We analyze the underlying mechanisms of these relationships using a 21-member model ensemble that includes both general circulation models and cloud resolving models.  We find a large spread in the change of intensity of the overturning circulation.  Both the range of the circulation intensity, and its change with warming can be explained by the range of the mean upward vertical velocity.  There is also a consistent decrease in the exchange of mass between the boundary layer and the midtroposphere.  However, the magnitude of the decrease varies substantially due to the range of responses in both mean precipitation and mean precipitable water.   This work implies that despite well understood thermodynamic constraints, there is still a considerable ability for the cloud fields and the precipitation efficiency to drive a substantial range of tropical convective responses to warming.