bluuebunny/crossref_metadata_2025 huggingface dataset:
Framework for the deployment of DNNs in remote sensing inversion algorithms applied to Copernicus Sentinel-4 (S4) and TROPOMI/Sentinel-5 Precursor (S5P)
Authors: Romahn Fabian , Molina Garcia Victor , del Aguila Ana , Lutz Ronny , Loyola Diego
Published: March 2022

In remote sensing, the quantities of interest (e.g. the composition of the atmosphere) are usually not directly observable but can only be inferred indirectly via the measured spectra. To solve these inverse problems, retrieval algorithms are applied that usually depend on complex physical models, so-called radiative transfer models (RTMs). RTMs are very accurate, however also computationally very expensive and therefore often not feasible in combination with the strict time requirements of operational processing of satellite measurements. With the advances in machine learning, the methods of this field, especially deep neural networks (DNN), have become very promising for accelerating and improving the classical remote sensing retrieval algorithms. However, their application is not straightforward but instead quite challenging as there are many aspects to consider and parameters to optimize in order to achieve satisfying results.

In this presentation we show a general framework for replacing the RTM, used in an inversion algorithm, with a DNN that offers sufficient accuracy while at the same time increases the processing performance by several orders of magnitude. The different steps, sampling and generation of the training data, the selection of the DNN hyperparameters, the training and finally the integration of the DNN into an operational environment are explained in detail. We will also focus on optimizing the efficiency of each step: optimizing the generation of training samples through smart sampling techniques, accelerating the training data generation through parallelization and other optimizations of the RTM, application of tools for the DNN hyperparameter optimization as well as the use of automation tools (source code generation) and appropriate interfaces for the efficient integration in operational processing systems.

This procedure has been continuously developed throughout the last years and as a use case, it will be shown how it has been applied in the operational retrieval of cloud properties for the Copernicus satellite sensors Sentinel-4 (S4) and TROPOMI/Sentinel-5 Precursor (S5P).
The Objective Deformation Component of a Velocity Field
Authors: Kaszás Bálint , Pedergnana Tiemo , Haller George
Published: March 2022

According to a fundamental axiom of continuum mechanics, material response should be objective, i.e., indifferent to the observer. In the context of geophysical fluid dynamics, fluid-transporting vortices must satisfy this axiom and hence different observers should come to the same conclusion about the location and size of these vortices. As a consequence, only objectively defined extraction methods can provide reliable results for material vortices.

As velocity fields are inherently non-objective, they render most Eulerian flow-feature detection non-objective. To resolve this issue,  we discuss a general decomposition of a velocity field into an objective deformation component and a rigid-body component. We obtain this decomposition as a solution of a physically motivated extremum problem for the closest rigid-body velocity of a general velocity field.

This extremum problem turns out to have a unique,  physically interpretable,  closed-form solution. Subtracting this solution from the velocity field then gives an objective deformation velocity field that is also physically observable. As a consequence, all common Eulerian feature detection schemes, as well as the momentum, energy, vorticity, enstrophy, and helicity of the flow, become objective when computed from the deformation velocity component. We illustrate the use of this deformation velocity field on several velocity data sets.
Identification and 3D modeling of active faults in the Dubrovnik (Croatia) offshore area – preliminary results
Authors: Sečanj Marin , Tomljenović Bruno , Stipčević Josip , Latečki Helena , Dasović Iva
Published: March 2022

The wider region around the city of Dubrovnik, encompassing coastal and offshore area of southern Croatia, is characterized by the relatively high seismicity rate with intermittent occurrence of strong events indicating the ongoing tectonic activity. Historical, instrumental and paleoseismological records show that this area was hit by at least dozen strong earthquakes in the last 500 years. Among these the most significant is the Great Dubrovnik earthquake from 1667 which devastated the region. This and other strong events of this area are related to several individual to composite seismogenic sources that generally extends in NW-SE direction from Albania to the central part of External Dinarides fold-thrust-belt in Croatia, still however, not yet sufficiently known in great details. Here, we aim to present preliminary results of identification and 3-D modeling of distribution and geometry of active faults in the offshore Dubrovnik area, based on analyses of reflection seismic profiles associated with deep borehole and surface geology data provided by the Croatian Hydrocarbon Agency.

Identification and classification of recently active faults in this area were performed by matching at least one of the following criteria: (1) offsets of the Pliocene - Quaternary deposits along faults that could be correlated between neighboring seismic lines, (2) deformation of Pliocene - Quaternary deposits above fault tips and (3) correlation of fault geometry and kinematics with distribution of the earthquake hypocenters and available fault plane solutions. In addition, a long-term neotectonic activity of identified faults has been studied by deformation and truncation of Miocene and Pliocene stratigraphic horizons that are frequently found affected by faults closely related with a long-term salt tectonics activity.

Location and geometry of the identified recently active faults are in good correlation with distribution of instrumentally recorded earthquake locations, where certain events are clustered within narrow zones of delineated fault planes. These preliminary results will be used for 3D geological and structural modelling of active earthquake generating fault systems between the city of Dubrovnik and the town of Ston, cross-section balancing and slip-rate calculation along active faults. In turn, these would provide input data for seismic shaking simulation and future seismic hazard assessment in this area.
Using Artificial Neural Network to estimate surface convective fluxes.
Authors: Jomé Mathilde , Lohou Fabienne , Lothon Marie , Kelley Jason , Pardyjak Eric
Published: March 2022

The earth’s surface and its properties impact, on different scales, the atmosphere. Thus, understanding the interactions between the surface and the atmosphere is important to establish and control global and regional numerical models. As a matter of fact, in February 2019, the Working Group on Numerical Experimentation (WGNE) reported that the bias observed on surface convective fluxes were the second source of errors in global and regional numerical models.

Reducing these errors by getting a better understanding of the impact of the surface-atmosphere interactions over heterogenous land surface is one of the main objectives of the Models and Observations for Surface-Atmosphere Interactions (MOSAI) project. Because experimental set-up that would help to study the impact of surface heterogeneity on surface convective fluxes is quite expensive, we tested a new method, based on Artificial Neural Networks (ANNs), that be proved efficient, in previous studies, in estimating surface convective fluxes at low cost. Standard low-cost meteorological stations are associated with higher-cost surface Eddy-Covariance flux stations so that station measurements can be paired to train the network on estimating surface fluxes based only on classical meteorological variables. Based on this, one may then estimate fluxes using this method on a set of various vegetation covers at the same time.

The first step is to test ANNs on well-known data. Two different datasets are used. The first one (twelve discontinuous sunny days), is a control dataset and allows to perform three type of tests to improve the estimated fluxes. The first group of tests concerns the influence of the training dataset, the second one concerns the topography of the network, and, the last one focuses on the choice of the input meteorological variables. The second dataset helps to deepen this study. The aim is to run the same tests but with a longer dataset (a dataset spanning over the course of an entire year, allowing for larger weather conditions) to propose some experimental deployment plan of the meteorological stations network and the Eddy-covariance station for the training of these stations, to apply this method to a future campaign. The first results proved for both datasets that estimating surface convective fluxes with ANNs using only a few variables and a simple topography is possible and would allow long-term monitoring of the surface energy fluxes over an heterogeneous surface.
A study on the influencing factors of Terra Nova Bay Polynya using satellite imagery, AWS, and reanalysis data
Authors: Kim Jinyeong , Han Hyangsun
Published: March 2022

Terra Nova Bay Polynya (TNBP) is one of the representative coastal polynya in East Antarctica. TNBP plays a major role of sea ice producers in the Antarctica, and it influences the regional current circulation and the surrounding marine environment. Therefore, it is important to investigate the influencing factors of TNBP. In this study, time series of TNBP area was estimated from Landsat-8 OLI/TIRS (2013-2016) and Sentinel-1 SAR (2017-2021) images by visually analyzing the boundary of polynya. To analyze the environmental factors influencing the area of ​​TNBP, wind speed, temperature, air pressure, and humidity measured at an automatic weather station installed near the polynya, and sea surface temperature, salinity and heat fluxes predicted by a reanalysis data were compared to the time series TNBP area. The area of TNBP showed a moderate correlation with the wind speed, but it was statistically low correlated with all other environmental factors. Meanwhile, a multiple linear regression between the time series area and all environmental factors showed a much higher correlation coefficient than between the polynya area and wind speed. However, the polynya areas predicted by the multiple linear regression model were largely deviated from those estimated from the satellite images. In future work, we intend to develop a model that retrieve more accurate TNBP area by selecting environmental factors suitable for polynya area estimation and applying them to machine learning techniques.
Innovative combination of ocean modeling and remote observations to track floating marine litter in the coastal area.
Authors: Declerck Amandine , Delpey Matthias , Voirand Thibaut , Liria Pedro , Epelde Irati , Mader Julien
Published: March 2022

The program “PlastEcoTrack”, or “PETrack”, aims at providing an operational support to reduce Floating Marine Litter (FML). More precisely, PET aims at supporting FML reduction strategies both downstream (interception at sea with collect vessels and on beaches with cleaning facilities) and upstream (source identification and reduction), by tracking the dispersion of FML in estuaries and in the coastal ocean. PETrack is currently supported by the European Spatial Agency through the “Plastic-less society” Feasibility Study, as well as by SUEZ group subsidiaries SERAMM and LYDEC.

Using a combination of innovative detection technologies and operational metocean modelling, the service targeted by PETrack will produce tailored decision-aid indicators to monitor and guide FML collect operations, including day-to-day operation support in near real time. Guidance offered by these indicators helps maximizing the amount of FML removed from the natural environment, while at the same time contributing to reduce the cost and impacts of operations (i.e. cost per kilogram of collected FML, fuel consumption, carbon footprint). Moreover, tracking technologies contribute to the reduction of FML emission at the source, by helping to identify most probable emission sectors depending on metocean conditions.

To achieve these purposes, PETrack combines innovative detection solutions based on satellite imagery and video monitoring in the coastal area, together with metocean-based FML transport modelling at local scale. In the operational mode of the service, it provides a decision-aid dashboard supporting day-to-day FML collect operations. The dashboard offers indicators aiming at guiding FML collect operations, to monitor and optimize their efficiency. It especially provides a tracking of FML in the coastal area and a prediction of concentration hotspots to guide collect vessel at sea; and anticipate massive onshore arrivals to help beach cleaning at land.

The service demonstration is under construction in the coastal Atlantic coast of Morocco, in the Casablanca area, and along the French Mediterranean littoral Marseille bay, North Western Mediterranean Sea. It took benefit of pre-existing components developed during the former LIFE LEMA (European Union LIFE program) and FML-TRACK (Copernicus Marine Service User Uptake) projects, which were further improved and complemented to bring the tool and service to a new stage of development and on new application sites with other configurations.
Remote sensing-based monitoring of the water surfaces in the Neusiedler See – Seewinkel National Park
Authors: Schauer Henri , Schlaffer Stefan , Büechi Emanuel , Dorigo Wouter
Published: March 2022

Topic:

Wetlands provide important ecosystem services,  e.g. for biodiversity and water resources. The salt pans in the Neusiedler See – Seewinkel National Park are a unique ecosystem for animal and plant species especially adapted to the extreme conditions prevailing in and around the salt pans. The conservation of the salt pans is largely based on the interplay with the water balance of the area and the influence of physical as well as anthropogenic factors. The large number of lakes, which are often only filled with water for a short time due to their shallow depth, makes monitoring by means of installed gauges more difficult. Remote sensing, on the other hand,  is an important source of consistent  information in space and time. In the FEMOWinkel project, which is funded within the framework of the Austrian StartClim 2021 program, long time series of multispectral satellite data are exploited for monitoring and data-driven modeling of water extent in the salt pans.

The water bodies are delineated based on image time series of the Landsat satellites, which have been providing data almost continuously since the 1980s. Cloud gaps will partly be filled with radar-based information provided by European Copernicus – Programme. The derived time series of water body extent and number are validated by comparison with aerial photographs and – where available – water levels. The salt pans are characterized with respect to their seasonal variability and their reaction to longer-term changes in water availability by comparison with ancillary data, e.g., surface and groundwater levels, climate data and other remote sensing products, such as soil moisture and vegetation indices. In the third step, a data-driven modeling of the lake extent is carried out using machine learning methods. We will also address the question of whether it is possible to predict the effects of dry or wet winters and springs on water body extent in the following summer using these methods.

Preliminary results of the time series analysis show a pronounced dynamic in the extent of the water bodies over the course of the study time. Periods, e.g., from 1990 to 1993 and 2001 to 2007, in which some of the lakes fell dry, alternated with wetter periods, e.g., from 1994 to 1999, in which the salt pans remained at least partially filled even in summer. These differences correlate with drought indicators such as the Standardised Precipitation-Evapotranspiration Index (SPEI). The remote sensing-based approach will make it possible to transfer the applied methods to other similar ecosystems located in steppe regions.
Whistler and electron cyclotron harmonic waves at the near-Earth dayside plasma sheet: statistics of modulation by ultra-low frequency waves 
Authors: Waheed Abdul , Bashir Muhammad Fraz , Artemyev Anton , Zhang Xiaojia
Published: March 2022

Magnetopause perturbations by solar wind transients drive a wide variety of ultra-low-frequency (ULF) waves in the Earth’s magnetosphere. Compressional ULF waves modulate thermal and energetic electron fluxes, changing their flux anisotropy. Such modulation may move electron distributions beyond the threshold of instabilities and drive the generation of electron cyclotron harmonic (ECH) and whistler-mode waves. Given the importance of ECH and whistler-mode waves for electron scattering into the atmosphere, we statistically investigate the main characteristics of ULF-modulated ECH and whistler-mode waves. We find two main types of events: with the correlation of whistler-mode and ECH waves and with their anti-correlation. We present the spatial distribution of these two types of events and examine correlations of background plasma/magnetic field characteristics with properties of whistler and ECH waves modulated by ULF waves.
Close-range hybrid solutions for glaciers instabilities monitoring
Authors: Giordan Daniele , Dematteis Niccolò , Troilo Fabrizio , Perret Paolo , Gotterdelli Simone , Morandini Luca
Published: March 2022

The dynamics that characterizes glaciers instabilities are often not well known because the study of these phenomena is done in many cases after their occurrence. A few examples of dedicated high resolution and high-frequency monitoring networks have been recently implemented to support risk assessment and management of glaciers affected by large potential instabilities.

The current climate trend and the rise of high mountain regions occupations by several anthropic activities have recently created areas affected by high potential risk due to the activation of glacial hazards, in particular during the summer season.

A few possible solutions are available: the substantial limitation of touristic exploitation of these areas or the management of the risk aimed to reduce the restrictions in accessing such high-value areas.

In this regard, it is required the implementation of high-resolution and high-frequency monitoring networks able to follow the evolution of the glacier and increase the knowledge of its dynamics.

In the Courmayeur municipality (Italy), the Planpincieux Glacier is a clear example of this critical condition: an active glacier with an unstable sector that could create a large ice avalanche that can reach the bottom of the valley, which is characterized by the presence of settlements and a famous touristic area.

For this reason, in the last decade, an innovative monitoring network has been implemented and tested in this very complex environment. The system comprises doppler radar, ground-based interferometric SAR and optical monitoring stations. The implementation of this hybrid network is a challenging task not only for the calibration of single instruments but also for the creation of network management that can acquire the dataset of different monitoring systems to obtain a precise representation of the evolution of the glacier. This is the final step that should be implemented for an effective strategy to support decision-makers.
Salt tectonic in the western subalpine foreland basin of Haute Provence? New insights on the Miocene Vélodrome syncline by a 3D geometrical modelling approach
Authors: Faure Agathe , Jolivet Laurent , Allanic Cécile , Gumiaux Charles , Loget Nicolas , Laurent Gautier , Callot Jean-Paul , Guiomar Myette
Published: March 2022

Recently, the understanding of the role of salt dynamics in the evolution of fold-and-thrust belts and foreland basins has significantly improved with the development of high-resolution seismics. Understanding a salt-related structure in the field as a mini-basin requires a thorough understanding of the 3-D geometries of folds.

In the western subalpine chain of Haute Provence, the Digne thrust area has undergone a complex tectonic history involving syn-sedimentary deformation, the migration of alpine front, late exhumation related to surface processes, and salt tectonics. In the front of the Digne thrust, the Vélodrome is an emblematic example of a complex fold displaying a 3D structure hardly explained by regional tectonics. The Vélodrome is an overturned syncline displaying a curved axis which direction changes from E-W in the north to N-S in the east and to E-W again in the south-eastern part. The Vélodrome is often interpreted as a growth fold with internal unconformities, but microstructural analyses (Fournier et al., 2008) have alternatively suggested a post-deposition folding. Moreover, recent studies (Graham et al., 2012; Celini, 2020) propose that the fold formed due to salt tectonics and interpret the Vélodrome as a mini-basin.

Thus, the Vélodrome complex tectonic structure requires a thorough understanding of the 3-D geometries to understand its tectonostratigraphic evolution.

This study aims at understanding the emplacement and the tectonic history of the Miocene Vélodrome series using in-situ field observations and drone field data to realize a 3-D geometrical model (GeoModeller - ©BRGM). More than 3000 structural data have been measured - both directly in the field and on 3D models obtained from drone image processing - and used in the GeoModeller to test the different hypotheses. The implicit approach offered by the GeoModeller and the field structural data-based approach bring an objective and new vision of 3-D geometries of the Vélodrome basin and confirm the Vélodrome as a syn-sedimentary fold. This study highlights several discontinuities inter- and intra-formations spatially localized. In the north of the Vélodrome, Aquitanian deposits do not present any unconformity, whereas internal unconformities can be observed in Burdigalian deposits. In the southeast of the fold, we observed internal unconformities both in the Aquitanian and Burdigalian deposits. This leads us to propose an early salt-related episode of deformation in the southeast part of the fold (Aquitanian) compared to the north, where deformation began only during the Burdigalian.
Estimating basin-scale groundwater storage change component in data-scarce area of Bandung Basin, West Java, Indonesia, using groundwater modeling and GRACE data
Authors: Rusli Steven Reinaldo , Bense Victor , Weerts Albrecht
Published: March 2022

Changes in groundwater storage are dominantly influenced by anthropogenic and climatic factors. In global and/or regional scale groundwater storage change studies, storage changes are often estimated using gravimetric satellite data (GRACE). However, the applicability of such analysis at basin-scale is still limited due to its relatively coarse spatial resolution of 1° x 1°. Combination of GRACE data with groundwater level monitoring observations, where available, and numerical modeling might yield more accurate results for catchment-scale studies.

In this study, we estimate the basin-scale groundwater storage change component in the data-scarce area of the Bandung groundwater basin in West Java, Indonesia, using MODFLOW. We parameterize the model using hydraulic conductivity data obtained from slug-tests, pumping-tests, and laboratory analysis. There is some historical groundwater level observation available to compare the model outputs against. The model is forced by recharge calculated with a distributed hydrological model (wflow_sbm). Groundwater abstraction is estimated based upon population density and other known water demands as reported in earlier studies. We simulate the period of 2005 to 2018, starting from an initial steady-state assumed to exist prior to 2005.

We compare the groundwater storage change observed in the model to that derived from GRACE data, which was calculated by subtracting the soil moisture change derived from the wflow_sbm simulation from the total terrestrial water storage change. The results show how the groundwater storage change estimated from the groundwater flow model can mimic both the dynamic and magnitude of that derived from GRACE in combination with wflow_sbm. The capability of groundwater modeling to estimate basin-scale groundwater storage change, validated by GRACE, unravel the opportunity of using such methods to predict the behavior of groundwater storage dynamics to the future impact of anthropogenic and climatic factor and to assist in deriving basin-scale groundwater policies and management strategies in data-scarce areas.
Simulating smoke dispersion and fire weather using NOAA’s next-generation numerical weather prediction model
Authors: Ahmadov Ravan , James Eric , Li Haiqin , Romero-Alvarez Johana , Trahan Samuel , Grell Georg , Kliewer Anton , Olson Joseph , Wang Siyuan , Zhang Xiaoyang , Li Fangjun , Kondragunta Shobha
Published: March 2022

NOAA has been transitioning its numerical weather predictions (NWP) models to the new models, which are based on Unified Forecasting System [https://ufscommunity.org/]. NOAA Global Systems Laboratory (GSL) in collaboration with other teams has been developing a new storm-scale NWP model – Rapid Refresh Forecasting System (RRFS) based on UFS. Currently the RRFS model is running in real time to provide experimental weather forecasting products [https://rapidrefresh.noaa.gov/RRFS/]. In the future the RRFS model will replace NOAA’s current operational High-Resolution Rapid Refresh (HRRR) NWP system.

Following on the successful HRRR-Smoke implementation in 2020, we started transitioning the smoke emission, plume rise, dry and wet removal simulation capabilities into the RRFS based using the Common Community Physics Package (CCPP) framework. The CCPP framework also ensures consistency between the physics and smoke/aerosol parameterizations. There are a number of new capabilities implemented in RRFS-Smoke. The high spatial resolution VIIRS I-band and high-frequency GOES-16/17 fire radiative power (FRP) data are ingested into the model to estimate both biomass burning (BB) emissions and fire heat fluxes every hour. Inline turbulent mixing of smoke within the boundary layer scheme, hourly wildfire potential to predict the evolution of the BB emissions, smoke interactions with the double-moment microphysics scheme and other new capabilities are implemented into the new RRFS-Smoke model.

The RRFS-Smoke model is simulated for August 2019 over the US by focusing on the FIREX-AQ field campaign [https://csl.noaa.gov/projects/firex-aq/]. The wide range of in-situ and remote sensing observations obtained onboard the DC-8 aircraft during FIREX-AQ provide valuable datasets to evaluate and improve the capabilities of the RRFS-Smoke model to accurately simulate BB emissions, smoke transport and mixing, and fire plume rise. Here, we present the simulations and evaluations of the RRFS-Smoke model for fire weather and smoke for some of the FIREX-AQ cases.
Modelling blue-green water fluxes in mountain headwaters at the climatic ends of High Mountain Asia
Authors: Fugger Stefan , Buri Pascal , Shaw Thomas Edward , Fatichi Simone , Miles Evan Stewart , McCarthy Michael , Fyffe Catriona , Kneib Marin , Jouberton Achille , Pellicciotti Francesca
Published: March 2022

Mountain catchments receive, retain, transport and release water that determines downstream ecology, landforms, hazards and human livelihoods. The hydrological regimes of such catchments are seasonally governed by the storage and release of water by snow and glaciers, and are modulated by the seasonality of liquid precipitation rates and energy fluxes. The wide range of climatic-topographical situations across High Mountain Asia creates a variety of hydrological regimes in this region.

In this study we apply a sophisticated modelling framework in two heavily glacierized catchments at opposite ends of the climatic spectrum in High Mountain Asia: an arid catchment with winter accumulation glaciers (Vaksh headwaters, Northern Pamir) and  a humid catchment with spring-summer accumulation (the Upper Parlung, South-Eastern Tibet). Both catchments span an elevation range of several thousand metres and a number of vegetation zones. To study the concomitant response of the cryosphere and biosphere, we use a land surface model with a mechanistic and energy-balance-based representation of both the cryosphere and biosphere, at 100m spatial and hourly temporal resolution. We force the model with statistically-downscaled and bias-corrected reanalysis data. For model setup and independent validation, we leverage extensive in-situ observations, collected at both sites. We complement those with spatial datasets, such as ice-dynamics-corrected glacier mass balance, snow cover, and vegetation indices.

We analyse the differences in the catchment water balance and flux partitioning between these two study sites in terms of energy fluxes, snow and glacier accumulation and ablation, vegetation distribution and phenology, and give special attention to patterns of evapotranspiration (ET). Using the model we determine the importance of supraglacial debris cover, widespread in the catchments, and its role in modifying the glacier mass balance under different moisture regimes. We also determine the links between snow melt seasonality, glacier mass balance, plant productivity and the responses in catchment runoff. This work presents one of the first applications of hyper-resolution land surface modelling to understand biosphere-cryosphere-hydrosphere interactions in High Mountain Asia, and will provide insights into the skills and drawbacks of such modelling approaches.
Characterization of particle number size distributions and new particle formation in different Indian locations
Authors: Sebastian Mathew , Kumar Kompalli Sobhan , Kumar Anil , Jose Sandhya , Babu S. Suresh , Pandithurai Govindan , Singh Sachchidanand , K. Hooda Rakesh , K. Soni Vijay , R. Pierce Jeffrey , Vakkari Ville , Asmi Eija , M. Westervelt Daniel , Hyvarinen Antii-P , P. Kanawade Vijay
Published: March 2022

Particle number size distribution has critical importance in characterizing the number, size, surface area, volume, and evolution of aerosols in the atmosphere. Atmospheric new particle formation (NPF) is one the largest source of aerosol numbers to the terrestrial atmosphere and greatly impact the evolution of particle number size distribution. Here, we analyzed at least one year of asynchronous measurements of particle number size distributions from six different locations in India. We found that NPF frequently occurs at all locations in the pre-monsoon season (March through May) and is the least common in the post-monsoon season (October-November).   Considering all sites (mountain background, mountain semi-rural, coastal semi-urban and urban), the particle formation rate of lowest detectable size (JLDS) varied by more than an order of magnitude (0.01 - 0.6 cm-3 s-1) and the growth rate between the lowest detectable size and 25 nm (GRLDS-25nm) by about three orders of magnitude (0.2 - 17.2 nm h-1). The site-specific JLDS and GRLDS-25nm are positively correlated, indicating their co-dependence on gas-phase production rates of low-volatility vapors, driven by the source and atmospheric conditions. Our results also showed that NPF events significantly modulate the shape of particle number size distributions, particularly in the pre-monsoon season. The NPF-associated CCN concentrations were higher in urban locations than the mountain background sites. Although using asynchronous measurements, our results implicate the process-level characterization of particle number size distribution.
Internal deformation of the Dolomites Indenter, eastern Southern Alps: structural field data and low-temperature thermochronology
Authors: Klotz Thomas , Pomella Hannah , Sieberer Anna-Katharina , Ortner Hugo , Dunkl István
Published: March 2022

The Dolomites Indenter represents the front of the Neogene to ongoing N(W)-directed continental indentation of Adria into Europe. Deformation of the Dolomites Indenter is well studied along its rim, documented by important fault zones such as the Periadriatic fault system, the Giudicarie belt, and the Valsugana and Montello fault systems. With this study, we aim to investigate the internal deformation of the Dolomites Indenter, which has been much less studied so far but is important for understanding crustal-scale processes during the Alpine orogeny.

 

Our approach to unravel the indenters exhumation and deformation history comprises (i) the compilation and acquisition of detailed structural and sedimentological field data within the Dolomites Indenter, (ii) a collection of a new and comprehensive low-temperature thermochronological dataset (this contribution), and (iii) crustal- to lithospheric-scale physical analogue modelling experiments (see contribution of Sieberer et al. in session TS7.2 – Internal deformation of the Dolomites Indenter, eastern Southern Alps: Orthogonal to oblique basin inversion investigated in crustal scale analogue models).

 

New field data comprise evidence for four distinguishable shortening directions. Examined intersection criteria along N-S cross sections covering the indenters extend from Periadriatic to Bassano fault system support a succession of Top SW, Top (S)SE, Top S and Top E(SE) movement. However, preexisting geometry strongly seems to affect the regional expression of respective compression phases and along strike variation of lineation trends can be observed within coherent fault systems.

 

The limited amount of existing thermochronological data already indicates the presence of relative vertical displacements within the Dolomites Indenter after the onset of indentation, including mostly Miocene apatite fission track (AFT) cooling ages along the Periadriatic and the Valsugana fault and several age clusters of Triassic to Jurassic AFT data. In order to obtain a detailed picture of the indenters thermotectonic evolution, an extensive set of samples has been collected along three roughly N-S striking corridors between Bolzano in the west and Tolmezzo in the east. In this contribution we present the new apatite (U-Th)/He and fission track data along the westernmost corridor (Mauls - Brixen - Valsugana - Schio).

 

The results of field work, comprehensive modelling of time temperature paths, and physical analogue modelling substantially contribute to the understanding of internal deformation and thus enable conclusions to be drawn about the processes at lithospheric scale.
The Role of Interplanetary Shocks for Accelerating MeV Electrons
Authors: Talebpour Sheshvan Nasrin , Dresing Nina , Vainio Rami , Afanasiev Alexandr
Published: March 2022

One source of solar energetic particle (SEP) events are shocks that are driven by fast Coronal Mass Ejections (CMEs). These can accelerate SEPs up to relativistic energies and are attributed to the largest SEP events. Even though the exact role of shocks for accelerating SEP electrons is still under debate, new studies suggest that CME-driven shocks can efficiently accelerate electrons to MeV energies in the vicinity of the Sun.

In this ongoing study, we present STEREO spacecraft observations of potential electron Energetic Storm Particle (ESP) events, characterized by intensity time series that peak at the time of the associated CME-driven shock crossing. We study near-relativistic and relativistic electrons during strong IP shocks between 2007 and 2018, to answer if the shock can actually keep accelerating electrons up to 1 AU distance. We use both, the Solar Electron and Proton Telescope (SEPT) and the High Energy Telescope (HET).

We focus especially on the MeV electron measurements and study if these are real or if the increases during the shock crossing are caused by strong proton contamination in the instrument. Therefore, we investigate the time profiles of the SEP events from the beginning until the crossing of the CME-associated shock and perform a correlation analysis of electron and proton intensities. We also investigate the in-situ plasma and magnetic field measurements at the spacecraft and analyze the energy spectrum of upstream regions of the shocks to shed light on the shock acceleration mechanism.
River infiltration into karst aquifer, Vipava Valley case study, Slovenia
Authors: Jelovčan Mateja , Brenčič Mihael
Published: March 2022

When and how the exchange of water between a river and an aquifer occurs is still poorly understood and investigated in many areas of the world, especially in complex karst areas. The same applies to Slovenia. As part of our research, we study the relationship between surface water and groundwater or the impact of infiltration of a non-karst watercourse on the water balance of a karst aquifer. The research is taking place in the south-western part of Slovenia, in the area where the Vipava River and the Classical Karst aquifer come into contact in the lower Vipava Valley. In the study area we have a well-defined Karst aquifer, which in its northern part is bounded by the Vipava River, which represents a hydrogeological boundary. The contact between the river Vipava and the Karst aquifer can thus also be considered as a contact karst where water losses occur.

The amount of water inflow into the Karst aquifer is determined by comparing the measured flows in successive sections in the Vipava River. For flow measurements, we use the Acoustic Doppler Current Profiler (ADCP) StreamPro with the associated WinRiver II software. Flow measurements are performed on selected cross-sections, where the exact velocity flow profile from the surface to the bottom of the profile is recorded at regular time intervals with the ADCP moving slowly and evenly across the river in both directions.

Based on the field work, it was found that the banks of the Vipava River are mostly quite overgrown and steep, so the riverbed is difficult to access. The river is about 5 m deep and about 30 m wide. The speed of the river is very slow, a few cm/s. The measurement (movement of the ADCP across the river) must be very slow due to the slow flow of the river; one passage of the river takes about 30 minutes. An important factor in performing measurements is also the wind and the increased amount of sediment in the water. The slow flow of the Vipava River, wind and the sediment are so far the main factors influencing the quality of the measured flows.

Flow measurements are currently performed on six cross-sections at 800 m of the Vipava River. The results of the measurements showed that on the first three consecutive profiles the flows in different water conditions in the downstream direction increase. The results of measurements on the remaining three consecutive profiles, however, showed that the flows between the profiles are comparable and do not show a trend. Measurements at different water conditions also showed that at lower flows (up to 3 m3/s) ADCP measurements are performed along the entire profile to the river bottom, while at higher flows the measurements are performed only up to a certain depth in the profile. The reason for this is the excessive scattering of the signal and therefore the rapid drop in intensity, which is due to the increased amount of sediment in the water. These are preliminary findings as measurements continue.
Values of geodiversity: a geoheritage oriented comparison
Authors: Mantovani Alizia , Giardino Marco , Lombardo Vincenzo
Published: March 2022

The characterization of geoheritage has a relevant role in the discussion of geoethics. What is geoheritage and what element of geoheritage should we conserve for the future generations? According to many authors, geoheritage are those parts of geodiversity that are relevant for human kind and are worthy to be included into geoconservation programs. The relevance of geodiversity is often expressed in literature through the use of lists of values that, according to the author who publishes it, make a geologic feature/a geodiversity element as part of geoheritage. 

Several authors proposed their lists of values. However, these lists present some differences: someone includes values that are not considered by other authors, or expresses them with different words. The consequence is that some elements of geodiversity, or, more in general, some geologic features could be considered as geoheritage only if a given list is taken into account. This situation may bring ambiguity when it comes to decide whether a feature is geoheritage, and can consequently bring to choose an inadequate strategy for geoconservation. For example, an underestimated feature will not be included into geoconservation programs, and an inappropriate use could ruin it. Viceversa, an overestimated feature can be overprotected, resulting in an obstacle for the local economy.  

This contribution aims to present, as an example, the differences between some of these lists of values. The core of the presentation is a table that highlights which of the values are the same and what are the differences (missing or differently expressed values). This is a step of a wider research, whose goal is to identify a method to limit ambiguities in the definition of geoheritage features, in order to support geopark and geosite’s stakeholders in the management of their territories and in the transparency of their decisions.
Influence of temperature and chlorophyll data assimilation on a biogeochemical ocean model for the North and Baltic Seas
Authors: Sathyanarayanan Anju , Li Xin , van der Lee Eefke , Marki Alexandra , Lorkowski Ina , Nerger Lars
Published: March 2022

The forecasting of physical and biogeochemical variables has always proven to be a challenge in marginal and coastal seas. Over the years, data assimilation has played a significant role in improving model accuracy for operational forecasting. In this study, we assess the impact of assimilating satellite sea surface temperature and chlorophyll data, and in-situ profile temperatures in an operational forecast model with the aim to improve the forecast of ocean variables in the North and Baltic Seas. For this purpose, we use the data assimilation software PDAF coupled to the biogeochemical ocean model HBM-ERGOM, which is used operationally at the BSH, and perform data assimilation using an ensemble Kalman filter. We conduct data assimilation experiments for a one-year period from October 2018 to September 2019. The study will discuss and quantify the effects of the data assimilation on the oceanographic and biogeochemical variables in the model and on the coupled interaction of ocean physics and biogeochemistry.
New ice margin chronology for the last deglaciation of the North American Ice Sheet Complex
Authors: Margold Martin , Dalton April S. , Heyman Jakob , Dulfer Helen E. , Norris Sophie L.
Published: March 2022

The North American Ice Sheet Complex (comprising the Laurentide, Cordilleran and Innuitian ice sheets) was the largest ice mass in the Northern Hemisphere that grew towards and waned after the Last Glacial Maximum. The existing ice margin chronology available for the North American Ice Sheet Complex is based on radiocarbon data only and does not reflect other geochronometric information constraining the last deglaciation, such as cosmogenic exposure- or optically stimulated luminescence ages. Here we present a series of newly produced ice margin isochrones from 25 ka to present, in a time step of 500 years. For each isochron, we draw maximum, best estimate, and minimum ice margin position in an attempt to capture the existing uncertainty. The ice margin isochrones are based on (i) an up-to-date dataset of radiocarbon ages (~5000), (ii) 10Be and 26Al cosmogenic nuclide data that directly date ~80 ice-marginal features over North America, (iii) ~350 optically stimulated luminescence ages dating the deposition of an aeolian cover immediately post-deglaciation, (iv) the ice-sheet scale glacial geomorphology record. Our effort brings the information on the last North American Ice Sheet Complex deglaciation on par with that for the Eurasian Ice Sheets and should serve the broad community of Quaternary research from archaeology to numerical ice sheet modelling.
Parameterization of Stomatal Conductance in a Subarctic Deciduous Shrub
Authors: Vatne Astrid , Vollsnes Ane Victoria , Pirk Norbert , Tallaksen Lena Merete
Published: March 2022

Plants play an important role in regulating the land-atmosphere water and carbon flux through stomata control. To avoid excess water loss, the stomatal conductance is reduced during low soil water availability or high water demand from the atmosphere. Atmospheric evaporative demand is projected to increase through an increase in vapour pressure deficit (VPD) in response to global warming. Stomatal conductance models used in earth system models often rely on empirical parameters. However, since VPD and soil moisture content often are correlated, it can be difficult to disentangle the effect of each driver in studies using field data. In this study, we evaluate the effect of VPD and soil moisture on stomatal conductance independently by conducting an experiment in controlled growth conditions. In the experiment, we will subject groups of dwarf birch (Betula nana) to increasing VPD in both well-watered and drying soil conditions and measure the effect on stomatal conductance and leaf scale water and carbon gas exchange. Dwarf birch is selected as it is widespread in high latitutes and our study focuses on land-atmosphere exchange in this region. The experimental design allows us to evaluate existing parametrizations of stomatal conductance and test hypotheses on how sensitive the parameters are to drought history.  The experiment will provide important knowledge on how to improve parameterization of water and carbon exchange in high latitude ecosystems. This presentation will show the first results of the experiment. This work is a contribution to the Strategic Research Initiative ‘Land Atmosphere Interaction in Cold Environments’ (LATICE) of the University of Oslo and the EMERALD research project.  