bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenging cloud-resolving simulations of Arctic mixed-phase clouds with airborne remote sensing observations
Authors: Schemann Vera , Kiszler Theresa , Mech Mario
Published: March 2022

For further process understanding and investigation, it is important to challenge the representation of ice and mixed-phase clouds in high-resolution simulations by detailed observations. These observations can be provided by remote sensing instrumentations on the ground, aircrafts or satellites as well as additional in-situ measurements of clouds. As these observations are always limited in dimension - either space, time or resolution, the analysis is not trivial and especially point-to-point comparisons in time are challenging if not impossible.

In 2017 the ACLOUD campaign took place in the Arctic - close to Svalbard. During the 5 weeks in early summer, Arctic mixed-phase clouds have been observed by two aircrafts - one for mainly remote sensing and one for in-situ measurements. We will show a statistical comparison of the remote sensing measurements with cloud-resolving simulations with 600m resolution. The simulations have been performed with the large-eddy version of the ICON model (ICON-LEM), the Seifert and Beheng two-moment microphysics and lateral boundary conditions based on operational global forecasts. Additionally, we will touch the question of representativity of these aircraft measurements. How representative are crosssections for the specific region, how should we compare those crosssections with the model and how much does the flight-day selection influence our results.
Isotopic signals across the forest water cycle
Authors: Floriancic Marius G. , Allen Scott T. , Kirchner James W.
Published: March 2022

Forests greatly impact the water cycle by redistributing water between the atmosphere and the subsurface, via processes including interception, infiltration, and transpiration. In order to understand which water is redistributed among different ultimate fates, and thereby better understand the role of vegetation in that process, we use stable isotopes to quantify transport processes across the different compartments of the forest water cycle. At our Waldlabor hillslope laboratory (Zurich, Switzerland) we have frequently measured and sampled water fluxes across the forest water cycle since April 2020. Specifically, we measure the isotopic composition in precipitation, throughfall, stemflow, bulk and mobile soil waters in depths of 10, 20, 40 and 80cm as well as in deep mobile water (from boreholes in the unsaturated zone up to 7m depth), groundwater and surface discharge at the outlet of the catchment. We also assess soil water uptake by beech and spruce trees from destructive sampling of twig xylem every three weeks.

The isotopic composition in precipitation was similar to what we found in throughfall and stemflow, so canopy interception processes did not substantially alter the isotopic signal. The seasonal variation in precipitation isotope composition was strongly dampened with depth in subsurface storages (through the soil layers, deep mobile water, and groundwater to streamflow). The assessment of the new water fractions in soil waters of different depths and the deeper soil drip water showed that the fractions of new precipitation in each layer decreased with depth. Although precipitation is almost equally distributed throughout the year, we found that soil new water fractions were generally smaller in summer compared than in winter. Water in spruce and beech xylem has a similar isotope signal throughout the year, potentially suggesting use of deep sources that contain a relatively stable mixture of summer and winter water. Together, these data provide opportunities for new perspectives on how subsurface flows and vegetation interact.
Artificial pebbles nourhisment on microtidal sandy beaches
Authors: sabatier francois
Published: March 2022

Artificial beach nourishment has become a common practice in coastal engineering. On sandy beaches, initiatives are emerging concerning pebble nourishment. Indeed, by increasing the granulometry, coastal managers hope to reduce shoreline recession more significantly than what would have been achieved by artificial sand nourishment.

In this presentation we estimate the effectiveness and impact of artificial pebble nourishment on two microtidal beaches along the French Mediterranean coastline: (1) exposed to wave in Camargue (annual Hsig = 3.5m)  and (2) subjected to low wave (annual Hisg < 2.0m) along the shoreline of the Etang de Berre. In both cases the beach has been recharged in order to widen it. On the beach exposed to waves, the nourishment did not significantly slow the retreat of the shoreline, whereas it succeeded in stabilizing it on the less exposed beach. In the Camargue, pebble deposits reworked by waves take the form of overwash. In both cases, the pebbles are subject to the dominant longshore littoral drift which exports the pebbles outside the nourished zone. We do not observe any significant morphological evolution of the surf zone, although we would expect an increase in slope in relation to the morphology that has become rather reflective in the swash zone. The pebbles remain on the foreshore and beach without moving offshore.

 
Eco-hydro-geomorphic evolution of the Sandal Divlit cinder cone, Kula, Turkey
Authors: Yetemen Omer , Avcioglu Aydogan , Celik Yavuz Selim , Simsek Ibrahim , Kolbuken Mesut , Yeo In-Young , Chun Kwok Pan , Gorum Tolga , Sen Omer Lutfi
Published: March 2022

In semi-arid ecosystems, microclimatic variations may lead to topographic asymmetry over geologic time scale due to uneven distribution of incoming solar radiation as a function of slope aspect. This phenomenon has long been recognized in geomorphology and mostly studied in catchments where may have a wide range of spatial heterogeneity in climate forcing and underlying lithology. The formation age and the size of the catchments add another level of complexity and uncertainty due to the fluctuations in prevailing climate and lithological differences in the studied catchments. However, cinder cones are natural laboratories to better understand the eco-hydro-geomorphic evolution resulted from the nonlinear interactions between vegetation, climate, and soil due to their small size, uniform lithology, well-constrained initial morphology, and relatively young age. The Sandal Divlit cinder cone located in the Kula volcanic field, western Turkey, is an inactive volcano and formed in the last stage of volcanism in the region. The climax vegetation in the primary succession following the volcanic eruption is observed on the north-facing slopes which host trees. The north-facing slopes have relatively deeper soils than south-facing slopes where host sparsely herbaceous plants and shrubs associated with thin and weakly developed soils. Airborne-LiDAR surveys and the digital elevation models having 5 m and 12.5 m spatial resolution were used to analyze the geomorphic descriptors and canopy structure of the cone as a function of aspect. The results show that north-facing slopes are steeper than south-facing ones due to better erosion protection as a result of denser vegetation. Despite its young age (<30 ka), the cone has developed topographic asymmetry and is imprinted with the signature of aspect-related vegetation difference. This finding is further evaluated and with the results of landscape evolution models to assess the role of microclimate due to vegetation on the development of asymmetric geomorphological features.

This study has been produced benefiting from the 2232 International Fellowship for Outstanding Researchers Program of the Scientific and Technological Research Council of Turkey (TUBITAK) through grant 118C329. The financial support received from TUBITAK does not indicate that the content of the publication is approved in a scientific sense by TUBITAK.
Gravitational volcano flank motion imaged by historical air photo correlation during the M7.7 Kalapana earthquake (1975), Big Island, Hawaii
Authors: Mannini Stefano , Ruch Joel , Hollingsworth James , Swanson Don , Johanson Ingrid
Published: March 2022

Volcanic islands are often subject to flank instability, being a combination of magma intrusions along rift zones, gravitational spreading and extensional faulting observable at the surface. The Kilauea is one of the most active volcano on Earth and its south flank show recurrent flank acceleration related to large earthquakes and magmatic intrusions. 
Here we focus on the M 7.7 Kalapana earthquake that occurred on 29 November 1975. It triggered ground displacement of several meters all over the south flank of the Kilauea volcano. The identification and quantification of the co-seismic rupture aim to better understand the overall flank motion and its connection to key structural components, such as between the southwest and east rift zones and the deep basal detachment where large earthquakes episodically nucleate.
Using optical imagery correlation technique, we analyzed the displacement that occurred during the 1975 earthquake. We used 26 and 22 historical air photos as pre-event (October 1974 and July 1975, respectively) and 7 and 44 for the post-event time period (December 1976 and March 1977, respectively).  Results show metrical horizontal displacement (north-south direction) along a 25 km long East West sector of the Kilauea south flank. We show that the ground rupture is continuous with most portions of faults that have been reactivated. Locally, the displacement values we found are in good agreement with punctual EDM measurements. Several fault segments have been activated close to the shore and their extension were previously unnoticed. Interestingly, we observe a constant increase of the offset away from the epicenter in the West direction, from a few meters up to ~12 meters, west of the Hilina Pali road. The deformation turns out to be higher where the faults are oriented NE-SW (western sector) compared to E-W oriented structures. It also shows that the flank is strongly influenced by gravitational effect, typical from large landslide processes. This observation provides additional information to better understand the connection between the Hilina fault system and the basal detachment.  Episodic flank motions on volcanic islands are rare events and this work contributes to the overall comprehension of volcano flank instability elsewhere.
Observations of root growth in stratified soils at the microscopic scale: Insights from micro-computed tomography
Authors: Nadimi Sadegh , Kemp Nina , Angelidakis Vasileios , Luli Saimir
Published: March 2022

Enhancing the overall resilience of vegetated slopes against shallow mass movement can be achieved by better understanding soil-root interaction.  To predict the behaviour of vegetated slopes during design, parameters representing the root system structure, such as root distribution, length, orientation and diameter, should be considered in slope stability models. Microscale quantifications of how root growth influences soil characteristics, able to inform computational models, are scarce in the literature, especially for stratified soils. This study quantifies the relationship between soil physical characteristics and root growth, emphasising particularly on (1) how roots influence the physical architecture of the surrounding soil structure and (2) how soil structure influences root growth. A systematic experimental study is carried out using high-resolution X-ray micro-computed tomography (µCT) to observe the root behaviour in layered soil. In total, 2 samples are scanned over 15 days of growth, enabling the acquisition of 10 sets of images. A machine learning algorithm for image segmentation is trained to act at 3 different training percentages, resulting in the processing of 30 sets of images, with the outcomes prompting a discussion on the size of the training data set. An automated in-house image processing algorithm is developed to provide values of void ratio and root volume ratio for Regions of Interest at varying distance from the root. This work investigates the effect of stratigraphy on root growth, along with the effect of image-segmentation parameters on soil constitutive properties.
High resolution topography precision maps for DEM differencing. Have they gone too far?
Authors: Strohmaier Florian , Goetz Jason , McColl Sam
Published: March 2022

In quantitative geomorphology, differencing of topographic models is widely used for sediment budgeting and monitoring landform changes in morphologically active areas. The value and utility of these analyses is partly contingent upon the data quality and uncertainties. Although there is recognition within the geoscience community of the need to account for uncertainties, such uncertainties are often under- or over-conservative, or fail to represent the spatial variability of error. 
Why is this the case? Do we need uncertainty estimates and error propagation to enhance our understanding of Earth surface processes? Do we need to establish the use of precision maps in geomorphology? Should it become part of a standard workflow? And to what detail?
We make an argument for the value of precision maps in topographic differencing models, and provide a methodology to generate and integrate precision maps into standard topographic differencing workflows.
We demonstrate the use of precision models in a sediment budgeting case study at the highly active Tarndale and Mangatu badass gully systems, located in New Zealand’s East Coast region. We constructed high resolution terrain models from UAV images with a Structure-from-Motion workflow for the period between 2018 and 2020. To estimate the spatial variability of errors in the terrain models, we made multiple synthetic flight simulations from each photoset and used these to statistically estimate cell-wise precision values. The resulting precision maps indicate the spatial variability of terrain model errors, which we propagated into our maps of erosion and deposition. These statistically-derived precision maps provide smaller – and thus more precise – confidence intervals helping to better quantify “true” gully erosion.
In this research we also discuss the implications our findings have for terrain model differencing in practice, including challenges in uncertainty estimation with large data sets. Overall, we aim to raise discussion and to strengthen the exchange between spatial statistics, geomorphology and geospatial communities!
Urban emissions of N2O and CH4 estimated from airborne active AirCore observations 
Authors: Tong Xin , Heuven Steven , Scheeren Bert , Kers Bert , Hutjes Ronald , Chen Huilin
Published: March 2022

Urban emissions of N2O and CH4 may be an important part of their total anthropogenic emissions. In this study, we aimed to independently estimate the fluxes based on direct observations focusing on two urban regions. We developed a new active AirCore (~6 L) system that is able to continuously collect air samples aboard aircraft. The sampling can last 2.5 hours with a typical flow rate of 40 mL/min, and the spatial resolution dependent on diffusion in the tubing as well is ~ 1800 m with a typical flight speed of 40 m/s. Several flights were conducted with the new active AirCore aboard a SkyArrow aircraft over the Groningen and Utrecht regions in 2020 and 2021. During a few of those flights, both the active AirCore and a commercially available LICOR-7810 analyzer for high precision CH4 were flown together. The in situ LICOR CH4 measurements were used to optimize the AirCore retrieval algorithm. The optimized AirCore CH4 showed a high agreement with the in situ LICOR CH4 measurements (R2 = 0.9998). Furthermore, a mass balance approach was utilized to derive CH4 fluxes. The preliminary results show that the estimated CH4 emission rate from three flights over the Groningen region is 41±28 mol/s, much higher than the yearly average emission rate (3.3 mol/s) from the EDGARv6.0 inventory in 2018, and we localize one potential source to be southwest outside the Groningen city. The CH4 estimated emission rate from one flight over the Utrecht region is 30 mol/s, also higher than the EDGARv6.0 mean value 2.2 mol/s.  Since the N2O signals are weak, we will explore whether it will be feasible to estimate the N2O emission rates based on these flights.
Geologic and Tectonic units in the Iranian Plateau from present and future satellite missions
Authors: Braitenberg Carla , Pivetta Tommaso , Pastorutti Alberto , Tesauro Magdala
Published: March 2022

The objective of this work is to investigate the geologic and tectonic units in the Iranian plateau in relation to the information that can be obtained from the gravity field observed from space. The objective requires to collect seismologic tomography, seismicity, geodetic observations of crustal movements, a database of active faults, active seismic investigations of sediment depths, heat flow measurements and to use this information as a constraint for gravity inversion with the present available satellite-derived gravity field. The gravity field correlated to the topography defines blocks of the plateau, which indicates varying crustal rigidity (Pivetta and Braitenberg, 2020). We find that mechanisms of vertical growth are tied to crustal thickening, coherently identified from the gravity field, seismic tomography and isostasy. Persistent high density crustal blocks are identified for instance SE of Isfahan, which require further investigation and validation, also in relation to magmatism. The study is embedded in a major project addressing the “Intraplate deformation, magmatism and topographic evolution of a diffuse collisional belt: Insights into the geodynamics of the Arabia-Eurasia collisional zones” financed by the Italian Ministry (PRIN 2017). When defining the density structure and its uncertainties, the question appears, what improvements on the knowledge of the structure, seismic faults, and on the block-structure can be expected from future gravity missions, with a payload of quantum gradiometers and atom-clocks in a multi satellite configuration. The geophysical sensitivity to quantum gravimetry in space is of interest to the MOCAST+ ASI project, a follower project of the MOCASS ASI project, in which the geophysical sensitivity of the quantum gradiometer payload has been studied (Pivetta et al., 2021).

Pivetta, T., & Braitenberg, C. (2020). Sensitivity of gravity and topography regressions to earth and planetary structures. Tectonophysics, 774, 228299. https://doi.org/10.1016/j.tecto.2019.228299

Pivetta, T., Braitenberg, C. & Barbolla, D.F. (2021) Geophysical Challenges for Future Satellite Gravity Missions: Assessing the Impact of MOCASS Mission. Pure Appl. Geophys. https://doi.org/10.1007/s00024-021-02774-3
The tectonic  activity assessment using minimum eroded volume and soil loss in Diyala river basin area
Authors: Ali Manal
Published: March 2022

The measurements of soil erosion, sediment transport, and soil deposition due to the tectonic activity regions retard the river basin development. The tectonic activity assessment in this area requires the identification of minimum eroded volume (MEV) and the soil loss (Sl) amount. The MEV, LS, and Hi indices have been used to develop relative tectonic activity Index (RTI) to identify probable zones of Hi, MEV, and SL in the Diyala River Basin (DRB). The results show that the north, north-eastern, and northwestern parts of the (DRB) are situated in the high (RTI) zone. The TIN model is used for estimating the MEV in the DRB and the (RUSLE) model is used for estimating the soil loss in the DRB. The MEV results in the DRB vary from 0 to 845 m3 in some areas. The result of soil loss in the DRB is varied from a minimum value of zero to a maximum of 91.34 t/h/y in some areas. The spatial distribution of MEV and SL in the (DRB) is classified into five types (Low Tectonic Activity, Slight Tectonic Activity, Moderate, High, and Extremely Tectonic Activity). From the results, it was observed that about 25.3% and 24.2% of the total study area are located in the very high relative tectonic activity and low relative tectonic activity zones, respectively. The large percentage of soil loss areas are 28.6% and 26.5% of the total study area are located in the very slight and slight, respectively.
Search for the parent body of the recently fallen iron meteorite
Authors: Golubov Oleksiy , Kyrylenko Ihor , Slyusarev Ivan , Visuri Jaakko , Gritsevich Maria , Krugly Yurij N. , Belskaya Irina , Shevchenko Vasilij G.
Published: March 2022

On November 7, 2020, a bright fireball was observed over Sweden, and 13.8 kg iron meteorite was later recovered. Multiple observations of the fireball were conducted from Denmark, Finland, and Norway, making it the first instrumentally documented fall of an iron meteorite.

We used the instrumental recordings of the bolide to reconstruct its preatmospheric orbit, and studied the past orbital evolution of the meteoroid. We found no close affinity of the orbit of the meteoroid with any near-Earth asteroid. The long YORP timescale suggests that the meteoroid could have arrived intact from the main asteroid belt. Our analysis of the orbit shows that the meteoroid probably entered its near-Earth orbit via either the 𝜈6 secular resonance with Saturn or the 3:1 mean motion resonance with Jupiter.

The work was partially funded by the National Research Foundation of Ukraine (project N2020.02/0371).
Chennai’s urban river systems – environmental changes, anthropogenic pollution and flood-induced remobilization
Authors: Bellanova Luisa , Bellanova Piero , Schwarzbauer Jan , Lehmkuhl Frank , Schulte Philipp , Reicherter Klaus
Published: March 2022

With a projected increase in frequency and magnitude of extreme weather events, the fast-growing coastal population centers of the Asian Global South experience a higher susceptibility to flood-related pollution. This is fueled by rapid land-use changes, urbanization, a multitude of emission sources, as well as anthropogenic- and flood-induced remobilization and relocation of pollutants. To yield a more comprehensive understanding of riverine and coastal floods in conjunction with these rapid urban and land-use changes, their impact on the environment and the health risks posed to local communities, sedimentary archives need to be studied.

Meandering through densely populated urban areas, Chennai’s rivers (Cooum and Adyar) and coastal systems have been affected by monsoon-induced floods (e.g., 2015 South Indian floods) and the 2004 Indian Ocean tsunami. Simultaneously, Chennai experienced an explosive population growth over the past 30 years, with the coinciding changes in land-use, urbanization, anthropogenic alterations to aquatic systems (e.g., damming, dredging), and (unregulated) environmental pollution. Especially the missing regulations, as well as growing volumes of sewage and physical waste have an enormous toll on the aquatic systems, but also pose threats by remobilization during floods.

To investigate potential flood-induced strata and chemostratigraphic changes over time, a total of nine sediment profiles along the Adyar and Cooum rivers are subject to GC-MS analyses of organic pollutants in correlation to stratigraphic changes in the obtained sediment profiles.

First results indicate that organic pollutants, such as petrogenic compounds (hopanes, PAHs), urban wastewater compounds (LABs, DEHA, methyl-triclosane), technical compounds (Mesamoll®, DPE, NBFA) and pesticides (e.g., DDX) allow for the identification of past flooding events and their characterization in terms of release and distribution of pollution. These proxies are used to assess (chemo-)stratigraphical alterations preserved in these sedimentary archives. However, sedimentary archives in fast-growing, urbanized environments are influenced by physical anthropogenic alterations leading to superimpositions or a hiatus in the sedimentary archives, thus hampering with the (chemo-)stratigraphic reconstruction of past flooding events and environmental changes.
“Fully-automated” clustering method for stress inversions (CluStress)
Authors: Kuslits Lukács , Czirok Lili , Bozsó István
Published: March 2022

As it is well-known, stress fields are responsible for earthquake formation. In order to analyse stress relations in a study area using focal mechanisms’ (FMS) inversions, it is vital to consider three fundamental criteria:

(1)       The investigated area is characterized by a homogeneous stress field.

(2)       The earthquakes occur with variable directions on pre-existing faults.

(3)       The deviation of the fault slip vector from the shear stress vector is minimal (Wallace-Bott hypothesis).

The authors have attempted to develop a “fully-automated” algorithm to carry out the classification of the earthquakes as a prerequisite of stress estimations. This algorithm does not call for the setting of hyper-parameters, thus subjectivity can be reduced significantly and the running time can also decrease. Nevertheless, there is an optional hyper-parameter that is eligible to filter outliers, isolated points (earthquakes) in the input dataset.

In this presentation, they show the operation of this algorithm in case of synthetic datasets consisting of different groups of FMS and a real seismic dataset. The latter come from a survey area in the earthquake-prone Vrancea-zone (Romania). This is a relatively small region (around 30*70 km) in the external part of SE-Carpathians where the distribution of the seismic events is quite dense and heterogeneous.

It shall be noted that though the initial results are promising, further developments are still necessary. The source codes are soon to be uploaded to a public GitHub repository which will be available for the whole scientific community.
 Menthol-induced bleaching as a tool to rear aposymbiotic foraminifera for symbiosis investigations 
Authors: Schmidt Christiane , Stuhr Marleen , Raposo Debora , Pochon Xavier , Davy Simon
Published: March 2022

Larger benthic foraminifera (LBF) are important carbonate producers in tropical and subtropical settings and play a large role in the carbon cycle. They suffer from bleaching (the expulsion/loss of the photosymbiotic microalgae) under increased sea surface temperature due to climate change. For artificial bleaching experiments, we used the diatom-bearing foraminiferan Amphistegina lobifera, because of its robustness in the laboratory for symbiosis investigations, and also the more sensitive Sorites orbiculus which hosts endosymbiotic dinoflagellates. In order to induce bleaching, the LBF were exposed to menthol at non-lethal concentrations. Additionally, DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) was applied as a photosynthetic inhibitor. After the 6 week experiment, foraminifera were >95% bleached, visible with the flourescence microscope. Survival rate of protists was high, as pseudopodial movement was still visible. The foraminifer in this bleached state was able to move and extend its pseudopodial network. The next step will be to test symbiont-uptake of those bleached foraminifera, and measure survival time and ecophysiological features of re-infected foraminifera.
Exploring the effect of instream boulders on large wood transport combining numerical modelling and field experiments
Authors: Marchesseau Jérémy , Lucía Ana , Comiti Francesco , Mignot Emmanuel , Ruiz-Villanueva Virginia
Published: March 2022

Large and relatively immobile sediment particles (i.e., boulders, usually defined with a diameter greater than 256 mm) are naturally delivered to rivers from hillslopes, transported by extreme floods, or produced by processes such as bed armouring. Boulder placement is also used as an artifical method for stabilizing channel beds and banks in river restoration projects. Natural or reintroduced boulders are important elements with a significant influence on channel hydraulics, erosion and deposition dynamics, and morphology. Still, little is known about their effect on large wood transported as floats along the river.

A field experiment was performed to track the mobility of cylindrical wood elements artificially placed in a reach of the Rienz River upstream from the city of Brunico, in South Tyrol (Northern Italy) and transported along a few kilometres over a period of three years. The Rienz River is a single thread sinuous gravel-bed river, characterized by the presence of several large boulders. Combining available field observations and 2D numerical modelling (coupling a 2D flow and a Lagrangian calculation of wood elements), this work aims to test the effect of boulders on both the river ecohydraulics and large wood transport. First, a detailed topography was obtained combining an available digital elevation model (2 m resolution) with topographical surveys. Second, the numerical model (i.e., Iber-Wood) has been calibrated with flow depths observations and the wood travel distances recorded during one high flow event were used for validation of the Lagrangian calculation. Finally, different scenarios with different boulder rearrangements are currently run to explore the effects of boulders size and location distribution on both wood transport and river ecohydraulics. This contribution will show preliminary results and discuss how boulder-rich channels differ from boulder-free channels in terms of large wood transport and deposition.
Site Characterization of Mohand Region along Himalayan Frontal Thrust (HFT) using passive HVSR method
Authors: Bhopya Naik Kethavath
Published: March 2022

  Bhopya K., Ghosal D., Verma S., Srivastav H., Verma S., Vikas

 The ongoing collision between the Indian and Eurasian plates has been accumulating strain along the Main Himalayan Thrust (MHT) causing the Sub-Himalaya highly vulnerable to Earthquakes. To examine seismic vulnerability in a hazard-prone area,  a complete understanding on its lithological properties like resonance frequency, shear wave velocity, bedrock depth, and thickness of overlying soft sediments is essential. As the study area spans from Madarsa Darul Quran to Mohand along the Himalayan Frontal Thrust (HFT) and lies in an earthquake-prone area, we record seismic ambient noise over twelve measuring points using a three-component portable seismograph (Tromino) with the natural frequency of 0.1 Hz. We carry out the HVSR (horizontal to the vertical spectral ratio) study on the recorded data using the Nakamura Method which is a technique for estimating the resonance frequency and site amplification caused by different stratigraphic units underlain by the top of the bedrock. The variable resonance frequency has been identified in this region in the range of 0.42 to 4.8 Hz, which indicates this region is prone to site amplification as overlain by Doon fan deposits. We invert the P-velocity (Vp), S-velocity (Vs), and density (ρ) by using Monte Carlo Inversion Method and identified three different stratigraphic units in this region. The top has a thickness of 3 meters with a mean Vs, Vp, and ρ as 218 m/s, 385 m/s, and, respectively. The second layer has a thickness of 6 meters with a mean Vs, Vp, and ρ of 406 m/s, 725 m/s, and 1.7 g/cm3, respectively. The bedrock depth in this region is 127 meters with a mean Vs, Vp, and ρ of 582 m/s, 1238 m/s, and 1.8 g/cm3 , respectively. This study will further help in response analysis up to a depth of bedrock.

 
Trench Aleutian anticyclonic eddies: generation and evolution
Authors: Khudyakova Sofia , Belonenko Tatyana
Published: March 2022

Aleutian eddies are mesoscale anticyclonic eddies formed within the Alaskan Stream over the
Aleutian trench in the area of 50-52 ° N, 170-175 ° E. It is found that canyons along the shelf
fault appear to be more prone to eddy activity than regions without canyons. Aleutian eddies
propagate southwestward after the separation from the Alaskan Stream and pass through the
Western Subarctic Gyre, carrying the transformed waters of the Gulf of Alaska to the western
part of the Pacific Subarctic. Fishermen and oceanographers are well aware of the role of
some anticyclonic eddies near the trenches in the formation of places favorable for fishing.
They are formed by the mixing of the waters of the Alaskan Stream and the waters of the
Subarctic Current. The appearance of Aleutian eddies is accompanied by a deepening of
isopycnic surfaces and an increase in temperature and concentration of dissolved oxygen in
the layer of 150– 400 m.
Based on the GLORYS12V1 data, the thermohaline structure of individual eddies and their
dynamic properties are analyzed. The GLORYS12V1 product is a global reanalysis covering
altimetry data since 1993. It is based on the existing real-time CMEMS (Copernicus Marine
Environment Monitoring Service) global forecasting system. The component of this model is
the NEMO platform controlled on the surface by ECMWF ERA-Interim. The observations
are then assimilated using a reduced-order Kalman filter. The work uses daily data for 2019
"GLOBAL_REANALYSIS_PHY_001_030" displayed on a standard regular grid in 1/12°
increments (approximately 8 km) and on 50 standard levels.
MHD wave modes of solar magnetic flux tubes with the realistic cross-section
Authors: Aldhafeeri Anwar , Fedun Viktor , Ballai Istvan , Verth Gary
Published: March 2022

 

Current and near-future high resolution solar observations indicate that theoretical modelling of the magnetohydrodynamic (MHD) modes in magnetic waveguides with realistic structure and shape now becomes an imperative necessity. 

It was recently shown that even a magnetic structure with elliptical shape, that corresponds to the weak irregularity, may significantly influence the spatial structure of MHD mode in comparison to the mode structure obtained from the modelling which is based on the magnetic flux tube shape with cylindrical cross-section (Aldhafeeri et al., ApJ, 2021). An inaccurate model used for describing waves may lead to the misinterpretation of observational data. 

The expressions for the linear MHD perturbations of a magnetic flux tube are derived by assuming zero value of the vertical component of the velocity perturbation at the boundary of the magnetic flux tube, which is in good agreement with observations. The governing equation for the vertical velocity perturbation was solved by taking into account the observed realistic shape of the sunspot umbra. With these conditions the proposed model is applicable for the analysis of slow body modes under photospheric conditions. 

Our results show that under solar photospheric conditions the conditions of continuity of the component of radial velocity and pressure at the boundary are enough to be imposed, enabling us to use Cartesian coordinates with varsity numerical methods to model the MHD modes with their realistic cross-sectional shape.

 
Temporal and spatial analysis for post-fire vegetation recovery in a Mediterranean site. An approach using optical Sentinel-2 and SAR Sentinel-1 imagery.
Authors: De Luca Giandomenico , Silva João M. N. , Modica Giuseppe
Published: March 2022

In this work, a multi-sensors temporal and spatial approach was carried out to monitor the vegetation post-fire recovery rate in a Mediterranean site (in part falling within the Nature2000 network) through the use of the optical Sentinel-2 and SAR C-band Sentinel-1 imagery temporal-series. The study area was observed for one year before and three years after the fire event. Several vegetation indices (VIs) were calculated for both optical (normalized difference vegetation index, NDVI; green NDVI, GNDVI; normalized red-edge vegetation index, NDRE, normal burn index, NBR; normalized difference water index, NDWI) and SAR (radar vegetation index, RVI; dual-polarized SAR vegetation index, DPSVI; radar forest degradation index, RFDI) data from which the temporal spectral profiles were extracted in the function of one of the three vegetation types (natural/semi-natural native forest, eucalyptus plantation and grasslands), of the burn-severity gradient, and of the orbit path of SAR satellite. What emerged is that the recovery spectral dynamics are highly influenced in terms of time and magnitude by both vegetation type and, mainly, burn severity. Optical Sentinel-2 observations showed that native woody and non-woody vegetation presented higher efficiency in restoring the ecological and physiological equilibrium by the observed time, whereas C-band SAR Sentinel-1 information seems to point out that the structural characteristics cannot be recovered in such a short time, although both the data appeared impacted by saturation. Climate variables, in particular monthly rainfall, compared and correlated with the temporal spectral profiles,  demonstrated to be very influential on the SAR signal, especially for a higher degree of burn severity. The spatial distribution of the post-fire recovery rate was estimated by calculating the burn recovery ratio (BRR), optimized using the random forest (RF) machine learning regressor model to account the natural phenological changes which affect unburned vegetation during the time.  The BRR results validated what had been recorded in the temporal profiles. The effectiveness of open-source data, software, and models interoperability for post-risk monitoring purposes of vulnerable habitats was also emphasized in this study.
Change in Climate Impact Assessment from CMIP5 to CMIP6 in a High-Mountaineous Catchment of Central Asia
Authors: Schaffhauser Timo
Published: March 2022

In this study we investigated the impacts of climate change on a large nivo-glacial river basin (Naryn Basin) in Central Asia (Kyrgyzstan) using two different families of General Circulation Models (GCMs). Hence, we use the widely used ISIMIP2 (Inter-Sectoral Impact Model Intercomparison Project) data which is based on the GCMs of the 5th stage of the Coupled Model Intercomparison Project (CMIP5), as well as the newly derived ISIMIP3 data, which uses the latest GCM data from phase 6 of CMIP (CMIP6) to drive a hydrological model (Soil Water Assessment Tool - SWAT). As both sources of forcing (ISIMIP2 & ISIMIP3) show considerable differences in multiple aspects such as used GCM family, projections, bias-adjustment technique and reference dataset, we evaluate and compare the individual projected changes of both generations on different variables of the hydrological cycle, such as snowmelt, evapotranspiration and soil moisture. In order to quantify the uncertainty contribution of different components along the modelling chain we perform a sensitivity analysis using an ANOVA (Analysis of Variance) approach. Hereby, it is intended to reveal which source (CMIP phase, GCMs, scenario) can be attributed the largest contribution. Results show that significant differences in the impact assessment can occur depending on the
CMIP generation. It is also shown that the CMIP phase has a high contribution to the total uncertainty estimates. However, in a next step special ephasize is put on the improvement of nivo-glacial processes, which will be performed by an improvement of the hydrological model SWAT, by integrating a glacier module which accounts for not only for glacier mass balance changes but also considers glacier recession and to a limited degree  potential advance.
Thermal Impact of High Temperature Aquifer Thermal Energy Storage on Overlying Layers
Authors: Heldt Stefan , Bauer Sebastian
Published: March 2022

High temperature Aquifer Thermal Energy Storage (HT-ATES) is one option to compensate for the seasonal mismatch between supply and demand in a renewable dominated heating sector. The thermal impacts to be expected by a planned HT-ATES plant can be predicted by numerical modelling, which is necessary for the development of monitoring concepts, legal authorization and economical assessments. One aspect of numerical pre-investigations, which was mostly disregarded by previous studies, is the assessment of thermal impacts in layers above the storage formation, which are heated conductively by the warm well. Furthermore, a quantification of the related heat losses and the implications on storage efficiency need to be considered.

The thermohydraulic processes induced by the HT-ATES are numerically simulated by a radially symmetric model neglecting ambient groundwater flow. The model includes the discretised warm ATES well, which reaches to a depth of ≈250 m and the surrounding geological layers. The geology and the operational scheme are based on a typical setting representative for northern Germany. The simplified operational scheme consists of half a year injection and half a year extraction, repeated for 50 years, with an injection temperature of 85 °C, varying return flow temperatures and an initial subsurface temperature of 13 °C. The thermal properties of the well casing are varied in a sensitivity study to estimate the influence of different material choices.

The model results show, that a temperature increase of 5 °C propagates 7 m radially in cohesive layers around the well in the first year of operation. After 50 years, temperature increases of 5 °C or more are found within a distance of about 40 m, 30 °C within about 13 m and 50 °C within about 2 m. Density-driven buoyancy flow is observed in cohesionless layers, leading to heat accumulation near the top of these layers. The heat consequently propagates significantly further there than in the cohesive formations, e.g. a temperature increase of 5 °C propagates maximally 121 m from the well in 50 years. The conductive heat loss to the overlaying formations through the well casing is 2 % of the injected heat. The such derived estimation of thermal impacts in overlaying formations is conservative, since ambient groundwater flow is neglected, which would result in lower temperatures due to advective heat transport away from the well. The heat loss, however, would be larger with groundwater flow, since this would reduce temperatures around the well and thus increase the temperature gradients and the conductive heat transport. Material choices of the well material may increase or decrease the heat losses and thus the thermal impacts.
Heatwaves under different future climate scenarios and impacts on children
Authors: Mollard James , Henley Sian F. , Bollasina Massimo
Published: March 2022

Periods of prolonged extreme warm temperatures, or heatwaves, have been shown to have significant impacts on human health, in particular affecting the young and old disproportionately. Observations over the past century show that the severity, frequency and duration of these heatwaves are increasing as global temperatures rise, and model simulations suggest there will be further increases in these characteristics in the future. 

We use a range of CMIP6 ScenarioMIP future simulations to show how heatwave characteristics change both globally and regionally. We show how these changes differ depending on the Shared Socio-economic Pathway (SSP) taken, highlighting the sensitivity of heatwaves to both global and regional warming in each scenario. The work also explores the non-linear trend between warming and heatwave characteristics, and how they vary in different future scenarios. The results suggest that the pathway followed has significant influence on heatwave attributes, and that attempting to limit changes by a set measure cannot be done by simply restricting the level of future warming to an agreed, designated temperature, such as the “1.5C above pre-industrial” figure often used in policy.  

Finally, we present how this work is been utilised in the production of the Children’s Climate Risk Index (CCRI), which provides the first comprehensive view of children’s exposure and vulnerability to the impacts of climate change. We also aim to highlight how indices like this are being used to help prepare resources for future issues related to climate events.  
Analysis of GNSS sensed slant wet delay during the severe weather events in central Europe
Authors: Hunegnaw Addisu , Duman Hüseyin , Elgered Gunnar , Dousa Jan , Teferle Norman
Published: March 2022

Over the last few decades, anthropogenic greenhouse gas emissions have increased the frequency of climatological anomalies such as temperature, precipitation, and evapotranspiration. It is noticed that the frequency and severity of the intense precipitation signify a greater susceptibility to flash flooding. Flash flooding continues to be a major threat to European cities, with devastating mortality and considerable damage to urban infrastructure. As a result, accurate forecasting of future extreme precipitation events is critical for natural hazard mitigation. A network of ground-based GNSS receivers enables the measurement of integrated water vapour along slant pathways providing three-dimensional water vapour distributions. This study aims to demonstrate how GNSS sensing of the troposphere can be used to monitor the rapid and extreme weather events that occurred in central Europe in June 2013 and resulted in flash floods and property damage. We recovered one-way slant wet delay (SWD) by adding GNSS post-fit phase residuals, representing the troposphere's higher-order inhomogeneity. Nonetheless, noise in the GNSS phase observable caused by site-specific multipath can significantly affect the SWD from individual satellites. To overcome the problem, we employ a suitable averaging strategy for stacking post-fit phase residuals obtained from the PPP processing strategy to generate site-specific multipath corrections maps (MPS). The spatial stacking is carried out in congruent cells with an optimal resolution in elevation and azimuth at the local horizon but with decreasing azimuth resolution as the elevation angle increases. This permits an approximately equal number of observations allocated to each cell. The spatio-temporal fluctuations in the SWD as measured by GNSS closely mirrored the moisture field associated with severe weather events in central Europe, i.e., a brief rise prior to the main rain events, followed by a rapid decline once the storms passed. Furthermore, we validated the one-way SWD between ground-based water-vapour radiometry (WVR) and GNSS-derived SWD for different elevation angles.

 
New insights in the understanding of the water balance in a subalpine forest in the Alps
Authors: Garcia-Santos Glenda , Obojes Nikolaus , Montagnani Leonardo
Published: March 2022

Subalpine forests in the Alps are fragile ecosystems with high importance for human water resources and the local and mesoscale climate. While previous studies have measured different components of the water balance, little is known about the partition of all the water components during the same period and the role of forest age. We were able to measure the water balance components and will show how water distributed in the forest. Some highlights of our study are the evidences that canopies of old forests were able to intercept water in larger extend than the young forest canopies, representing the largest water reservoir, the frequency of fog during the study period, shown for the first-time in this ecosystem, the larger ratio of throughfall related to precipitation during days with mixed precipitation (fog and rainfall) and the role of epiphytes in the water balance.