bluuebunny/crossref_metadata_2025 huggingface dataset:
Aeolian processes at the ExoMars 2022 landing site 
Authors: Silvestro Simone , Vaz David , Pacifici Andrea , Chojnacki Matt , Salese Francesco , Neesemann Alicia , Tirsch Daniela , Popa Ciprian , Pajola Maurizio , Franzese Gabriele , Mongelluzzo Giuseppe , Fabio Cozzolino , Porto Carmen
Published: March 2022

Wind-formed features are abundant in Oxia Planum (Mars), the landing site of the 2022 ExoMars mission, which shows geological evidence for a past wet environment [1-4]. Here we show that the landing site experienced multiple climatic changes recorded by an intriguing set of ridges that we interpret as Periodic Bedrock Ridges (PBRs) [5, 6]. Clues for a PBR origin result from ridge regularity, defect terminations, and the presence of preserved megaripples detaching from the PBRs. PBR orientation differs from superimposed transverse aeolian ridges pointing toward a major change in wind regime. Superposition relationships of the PBRs with a dark-toned geological unit [4] indicate that such a change in the main wind condition likely occurred during the Amazonian. Active bedform migration from nearby craters (McLaughlin and Oyama) show winds coming from the North, matching the orientation of the wind streaks visible in the putative landing ellipse. Our results provide constrains on the wind regime in Oxia Planum and offer indications on present and past winds that will be crucial for understanding the landing site geology.

For full details, see [1].

[1] Silvestro, S. et al. 2021. Periodic Bedrock Ridges at the ExoMars 2022 landing site: Evidence for a Changing Wind Regime. GRL, 48, 4.

[2] Favaro, E. et al. 2021. The Aeolian Environment of the Landing Site for the ExoMars Rosalind Franklin Rover in Oxia Planum, Mars. JGR, 126, 4.

[3] Balme, M. et al. 2017. Surface-based 3D measurements of small aeolian bedforms on Mars and implications for estimating ExoMars rover traversability hazards. PSS, 153, 39-53.

[4] Quantin, C. et al. Oxia Planum: The Landing Site for the ExoMars ‘‘Rosalind Franklin’’ Rover Mission: Geological Context and Prelanding Interpretation. Astrobiology, 21, 3.

[5] Montgomery, D. R. et al. 2012. Periodic bedrock ridges on Mars. JGR, 117, E03005.

[6] Hugenholtz, C. H. et al. 2015. Formation of periodic bedrock ridges on Earth. Aeolian Research, 18, 135–144.
Explicit IMF By-dependence of magnetospheric energetic protons and the ring current
Authors: Holappa Lauri , Buzulukova Natalia
Published: March 2022

The interaction of the solar wind with the Earth’s magnetic ﬁeld produces geomagnetic activity, which is critically dependent on the orientation of the interplanetary magnetic ﬁeld (IMF). While the dawn-dusk (By) component of the IMF is known to play an important role in this interaction, its effects are usually assumed to be independent of its sign. However, recent studies have shown that auroral electrojets and substorm activity are stronger for By < 0 in Northern Hemisphere (NH) summer. This so-called explicit By-dependence is reversed for NH winter. Here we study how IMF By modulates magnetospheric energetic protons and the ring current by using measurements of NOAA POES satellites and the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model coupled in with the global BATSRUS MHD code. We show that the energetic magnetospheric protons and the ring current (Dst index) exhibit an explicit By-dependence (stronger for By < 0 in NH summer), which can be reproduced by the model. Our results highlight the importance of the IMF By component for space weather and must be taken into account in the future space weather modeling.
A new perspective on projected precipitation changes in Tanzania
Authors: Gleixner Stephanie , Lehmann Jascha , Gornott Christoph
Published: March 2022

Informed decision-making on adaptation strategies for future climate change need reliable climate information. In particular, vulnerable economies like Tanzania, which is strongly reliant on rain-fed agriculture, struggle with the lack of agreement on precipitation changes between the climate models. In order to find robustness in these projections, we compare precipitation simulations from the CORDEX Africa Ensemble under three emission scenarios (RCP 2.6, RCP 4.5, RCP 8.5) within different precipitation categories defined by the Standardized Precipitation Index (SPI). We find that despite the disagreement on the sign of the total precipitation trend, there is strong agreement among on a decrease in normal conditions and an increase in both extreme wet and extreme dry conditions throughout the 21st century. The differences between the projections in terms of total precipitation are related to shifts of (near) normal conditions to wetter conditions in the case of ‘wetter’ projections and to drier conditions for ’drier’ projections. These results indicate an overall broadening of the rainfall distribution especially toward extremely wet conditions.
Drought effects on whole-tree C dynamics in an enclosed tropical rainforest
Authors: Ingrisch Johannes , Kübert Angelika , Huang Jianbei , Meeran Kathiravan , van Haren Joost , Shi Lingling , Bamberger Ines , Kreuzwieser Jürgen , Lehmann Marco , Dippold Michaela , Meredith Laura , Ladd Nemiah , Bahn Michael , Werner Christiane
Published: March 2022

Drought exerts a major control on the carbon (C) cycle of terrestrial ecosystems worldwide. However, the mechanisms and processes underpinning ecosystem responses remain uncertain, in particular in diverse, tall-growing ecosystems like tropical rainforests. In such ecosystems, trees are a predominant driver of ecosystem C cycling, as they link the major ecosystem fluxes, photosynthesis and ecosystem respiration through allocation and utilisation of recent assimilated C. Trees respond dynamically to drought, generally by reducing C assimilation and altering investments of recent C into metabolism, defence, growth and storage, which has consequences for the fate of C in the system. However, to date most of our understanding is derived from experiments on small trees and we lack an understanding of how whole-tree C allocation responds in diverse, stratified forest ecosystems.

To address this knowledge gap, we implemented a 9.5-week experimental drought in the world’s largest controlled growth facility, the Biosphere 2 Tropical Rainforest in Arizona, US. We continuously measured isotopic CO2 fluxes of leaves, stem and soil as well as leaf and phloem non-structural carbohydrates across a range of canopy and understory forming trees during pre-drought and drought conditions. To study drought effects on the fate of recent photoassimilates, we labelled the entire ecosystem with a 13CO2 pulse during pre-drought and drought conditions and traced the carbon flow in leaf, stem and soil fluxes and non-structural carbohydrates of leaves and phloem.

Across all studied trees, drought generally reduced CO2 uptake and metabolic activity in leaves, stems and soil. The phloem transport rates slowed down and the turnover of recent photoassimilates declined. As drought progressed respiration was increasingly fuelled by C reserves, as indicated by isotopic flux dynamics and a depletion of starch pools, particularly in leaves. Drought response patterns of fluxes, carbohydrate pools and C allocation dynamics were highly variable among trees. Interestingly, response diversity was not primarily explained by species identity, but likely related to a combination of functional and structural traits and the trees’ microenvironment within the forest. We conclude that the structural and functional composition of a forest is an important driver for tree C allocation and needs to be considered for understanding the mechanisms underpinning forest C dynamics in response to drought.
Elevational patterns of climate change – an assessment of temperature and precipitation for the mountain regions of the world
Authors: Schöner Wolfgang , Pepin Nicholas , Arnone Enrico , Gobiet Andreas , Haslinger Klaus , Kotlarski Sven , Notarnicola Claudia , Palazzi Elisa , Seibert Petra , Serafin Stefano , Terzago Silvia , Thornton James M. , Vuille Mathias , Adler Carolina
Published: March 2022

Mountains and high elevation regions are often viewed as climate change “hotspots” which are responding particularly rapid to global climate forcing and may anticipate or amplify what is occurring elsewhere. Accelerating mountain climate change has widespread impacts ranging from an enhanced loss of snow and ice, through impacts on the hydrological regimes, to changes in ecological zonation as species move uphill. We examine global evidence for elevation contrasts in temperature trends (also known as elevation-dependent warming, EDW) and precipitation changes. We performed a meta-analysis of existing studies, which used in-situ station temperature and precipitation data from mountain regions as reported by the IPCC, and we analysed global gridded datasets (observations, reanalyses and model hindcasts). In both cases, we examined the elevation dependency of temperature and precipitation changes since 1900. The meta-analysis indicates that studies using pairs of station groups (in mountains and nearby low elevation areas) show a tendency towards enhanced warming at higher elevations. However, when all past studies of observations are combined globally, no systematic difference in warming rates for high vs. low elevation groups is found. Thus, on a global scale, local and regional features may obscure EDW. Precipitation changes in mountain areas based on station data are inconsistent, and a global elevational gradient in precipitation trends does not emerge. Gridded datasets (CRU, GISTEMP, GPCC, ERA5, CMIP5) show increased warming rates at higher elevations in specific regions (e.g. Andes for CMIP5 and Greater Alpine Region for ERA5), but again, there is no universal amplification of warming in mountains. The agreement between datasets is weak for temperature. Changes in precipitation show a tendency towards weaker (stronger) increase at higher (lower) elevations, especially in mid-latitudes. This means that the orographic effect may be weakening on a global scale, which may be a result of both thermodynamics and changes in atmospheric circulation.
Evaluations of microphysics in NICAM using a polarimetric radar and a 94 GHz Doppler radar in Japan
Authors: Roh Woosub , Satoh Masaki
Published: March 2022

It is important to evaluate and improve the cloud properties in global non-hydrostatic models like a Nonhydrostatic ICosahedral Atmospheric Model (NICAM, Satoh et al. 2014) using observation data. There are intensive observation stations over the Tokyo metropolitan area in Japan. The ULTIMATE (ULTra sIte for Measuring Atmosphere of Tokyo metropolitan Environment) is proposed to verify and improve high-resolution numerical simulations based on these observation data.

The C-band Polarimetric radars are in Haneda and Narita airports. A polarimetric radar can observe the additional information of hydrometeors related to the shapes and retrieve the hydrometeor identification based on polarimetric variables. 
In this study, we used the Joint simulator, which is developed for The EarthCARE satellite, which has Cloud Profiling Radar (CPR, 94 GHz) and High Spectral Resolution Lidar (HSRL). The EarthCARE Active Sensor Simulator (EASE, Okamoto et al. 2007, 2008; Nishizawa et al. 2008) in the Joint simulator can simulate signals of CPR and HSRL on the ground. POLArimetric Radar Retrieval and Instrument Simulator (POLARRIS, Matsui et. al. 2019) were implemented in the Joint simulator for the polarimetric radar. 

We introduced our evaluation method and results of our microphysics using polarimetric radars and the CPR.

 
Can landslide inventories developed by artificial intelligence substitute manually delineated inventories for landslide hazard and risk studies?
Authors: Meena Sansar Raj , Floris Mario , Catani Filippo
Published: March 2022

Landslide inventories are essential for landslide susceptibility mapping, hazard modelling, and further risk mitigation management. For decades, experts and organisations worldwide have preferred manual visual interpretation of satellite and aerial images. However, there are various problems associated with manual inventories, such as manual extraction of landslide borders and their representation with polygons, which is a subjective process.  Manual delineation is affected by the applied methodology, the preferences of the experts and interpreters, and how much time and effort are invested in the inventory generating process. In recent years, a vast amount of research related to semi-automated and automatic mapping of landslide inventories has been carried out to overcome these issues. The automatic generation of landslide inventories using Artificial Intelligence (AI) techniques is still in its early phase as currently there is no published research that can create a ground truth representation of landslide situation after a landslide triggering event. The evaluation metrics in recent literature show a range of 50-80% of F1-score in terms of landslide boundary delineation using AI-based models. However, very few studies claim to have achieved more than 80% F1 score with the exception of those employing the testing of their model evaluation in the same study area. Therefore, there is still a research gap between the generation of AI-based landslide inventories and their usability for landslide hazard and risk studies. In this study, we explore several inventories developed by AI and manual delineation and test their usability for assessing landslide hazard.
Soil CO2 efflux along a soil warming gradient in subarctic grasslands in Iceland
Authors: Protti Sanchez Fabrizzio , Janssens Ivan , Sigurdsson Bjarni D. , Sigurdsson Páll , Bahn Michael
Published: March 2022

Cold and high-latitude terrestrial ecosystems, such as the arctic and the subarctic, store large amounts of carbon (C) in the soil. These ecosystems are already experiencing rapid rates of temperature increase compared to other regions of the Earth. It is expected that warmer conditions will increase soil CO2 efflux by enhancing soil microbial and root respiration. However, our understanding of warming effects on soil C cycling is limited to short-term observations (1-5 y of warming) and under few discrete warming levels.

This study is embedded within the FutureArctic project, and we take advantage of geothermally heated subarctic grasslands in the ForHot research site in Iceland, with 13 years of a stable and constant soil warming gradient. The main objective of this research is to get deeper insights into how rising temperatures will affect soil carbon fluxes in subarctic grasslands ecosystems.

Using automated long-term soil chambers, we are continuously measuring soil CO2 efflux rates along a soil warming gradient ranging from +0°C to ca. +14°C above ambient soil temperature. Furthermore, complementary manual soil CO2 efflux measurements allow us to cover higher spatial variability and to assess how soil warming affects the main soil CO2 source components (i.e., autotrophic, and heterotrophic respiration) via the trenching approach.

Here, we present preliminary results of the soil CO2 efflux along a soil warming gradient in Iceland, including time series of the first year of the study. Overall, soil CO2 efflux increased along the soil warming gradient. We found that heterotrophic respiration is the main source component of total soil CO2 efflux. Both autotrophic and heterotrophic respiration increased with warming, however, the relative contribution of each source component was unresponsive to warming. Ongoing analysis of isotopic soil CO2 in the automated measurements will allow the partition between biogenic and geogenic sources of soil CO2 in the studied geothermal system and accurately describe the soil respiration response to warming.
Tectonic processes responsible for various wavelengths of permanent deformation on the western coast of South America
Authors: Freisleben Roland , Jara-Muñoz Julius , Melnick Daniel , Strecker Manfred , van der Beek Peter
Published: March 2022

Abstract. The tectonically active western coast of South America is characterized by the accumulation of deformation that contributes to permanent uplift of the Andean forearc at glacial-cycle timescales. However, the individual mechanisms responsible for long-term coastal uplift are still debated, mostly because analyses at continental-scale have not been carried out as yet. In coastal realms, permanent deformation is often estimated from marine terraces, which depict the interplay between wave erosion, tectonic uplift, and sea-level changes. Based on ~2000 elevation measurements of last interglacial marine terraces, we performed wavelength analyses using fast Fourier transforms. We compared the resulting uplift-rate signal with various tectonic processes and subduction parameters associated with the accumulation of permanent deformation. We detected a constant background signal of uplift along the South American margin (median rate: 0.22 mm/yr), which is disturbed by short-, intermediate- and long-wavelength changes between ~20 and ~800 km wavelengths, with the most prominent wavelengths at scales of ~500 km. Similarities between the wavelength spectra of uplift rate and signals from tectonic parameters suggest potential correlations, although multiple individual mechanisms usually contribute to a larger wavelength peak or to a certain range of wavelengths. For instance, crustal faulting is responsible for short-wavelength deformation (<100 km) and strong megathrust earthquakes (MW>7.5) mostly cover wavelength ranges from ~100 to 200 km, despite reaching wavelengths over 600 km as well. The subduction of bathymetric anomalies and the extent of interseismic locking correlate with intermediate wavelengths (~200 to ~500 km), whereas residual gravity anomalies, basal friction, and background seismicity correlate with long-wavelength deformation (>500 km). We suggest that the constant background signal of uplift rate results from two possible mechanisms: (a) a combination of multiple processes acting at different wavelengths, times and locations over millennial timescales or (b) a single unidentified process acting homogeneously along the western South American margin. With this study, we highlight the application of novel signal analysis approaches to elucidate the mechanisms driving surface deformation in subduction zones on different spatial and temporal scales.
The Framework of Relativistic Geodesy: What do we know?
Authors: Philipp Dennis , Laemmerzahl Claus , Hackmann Eva
Published: March 2022

Conventional geodesy builds on (the concepts of) Newtonian gravity. Thus, at the level of a relativistic theory of gravity, the underlying framework needs to be extended and basic notions need to be generalized.
This opens an entirely new perspective on the matter - chronometric geodesy - which investigates gravity by, e.g., the use of clocks and clock networks.
In this talk, the status of the theoretical framework of relativistic geodesy will be discussed and basic concepts such as the potential(s), multipole moments, geoid, reference ellipsoid, and height notions in the conventional and in the relativistic framework will be addressed. Moreover, observables and measurement prescriptions are discussed and an outlook on future developments is given.
Soil Quality Assessment after 25 Years of Sewage Sludge vs. Mineral Fertilization in a Calcareous Soil
Authors: Simoes da Mota Ana
Published: March 2022

This study identified the most sensitive soil quality indicators to assess soil quality in the framework of a long-term application of sewage sludge (SS) and conventional mineral fertilization for rainfed cereal production in a sub-humid Mediterranean calcareous soil. The SS treatments (at different doses and frequencies were compared with a mineral fertilization (MF) treatment and with a control treatment (no fertilization). Twenty-five years after the onset of the experiment, 37 pre-selected soil physical, chemical and biological parameters were measured, and a minimum data set was determined. The indicators significantly affected by treatment and depth were selected as sensitive.

A principal component analysis (PCA) was performed for each studied depth. At 0-15 cm, three factors (F1, F2 and F3) and at 15-30 cm, two factors (F4 and F5) were identified and explained 71.5% and 67.4% of the variation, respectively, in the soil parameters. The most sensitive indicators were related to nutrients (P and N), organic matter, and trace elements (F1 and F4), microporosity (F2), earthworms’ activity (F3), and exchangeable cations (F5). Only F3 correlated significantly (and negatively) with yield. This study demonstrated soil quality can be affected in opposite directions by SS application, and that a holistic approach is needed to better assess soil functioning under SS fertilization in this type of agrosystems.
Baseflow recession characteristic variation with the Basin Morphology. 
Authors: Hameed Mehvish , Nayak Munir Ahmad , Ahangar Manzoor Ahmad
Published: March 2022

In the absence of precipitation or any other artificial input source, base-flow, a component of streamflow, sustains natural surface water bodies like rivers and streams. Therefore understanding, identifying, and extracting baseflow from streamflow measurement is essential for many hydrological studies, e.g., estimating watershed characteristics, long-term groundwater storage trends, flow regulations or water policy, water quantity, quality, supply, habitat and informing management of regional water resources. We aim to understand the morphologic factors that are known to influence groundwater outflow, for example, slope, length of the stream, drainage density, stream order, stream frequency on the baseflow recession characteristic or storage delay constant (K) in the watershed. We study how (K) varies with the choice of different estimation methods like using streamflow recession analysis by Brutsaert, (2008) algorithm, our newly developed algorithm for baseflow analysis, and using one of the solutions of Bossinesq’s groundwater flow equation. Using the aforementioned three techniques, the influence of significant morphologic characteristics is found for 56 small watersheds within the large watershed of the Rock River basin over the study period of 1990-2021. Using factor analysis we rank morphologic parameters in terms of their relative influence on (K). The findings of our study suggest that the morphologic parameters that influence the storage delay constant are intercorrelated and play a complex role in shaping the (K) values.
MAGEMin, a new and efficient Gibbs free energy minimizer: application to igneous systems
Authors: Riel Nicolas , Kaus Boris , Green Eleanor , Berlie Nicolas
Published: March 2022

Modelling stable mineral assemblage is crucial to calculate mineral stability relations in the Earth’s lithosphere e.g., to estimate thermobarometric conditions of exposed rocks and to quantify the fraction and composition of magma during partial melting. Accurate prediction models of stable phase are also fundamental to model trace element partitioning and to extract essential physical properties such as, fluid/melt/rock densities, heat capacity and seismic velocities. This thus forms a crucial step in linking geophysical observations with petrological constraints.

Here, we present a new Mineral Assemblage Gibbs free Energy Minimizer (MAGEMin). The package has been developed with the objective to provide a minimization routine that is easily callable and fulfilling several objectives. Firstly, the package aims to consistently compute for single point calculations at given pressure, temperature and bulk-rock composition with no needed a priori knowledge of the system. Secondly, the package has been developed for stability, performance and scalability in complex chemical systems. Finally, the code is fully parallel and we directly translate THERMOCALC formulation of solution models which yields easier and faster updates, less prone to implementation mistakes.

As a proof of concept we apply our new approach to the thermodynamic dataset for igneous systems of Holland et al. (2018). The database works in the NCKFMASHTOCr chemical system and has been updated to account for the new plagioclase model Holland et al. (2021).
Automatic detection of solar magnetic tornadoes based on computer vision methods.
Authors: Vorobev Dmitrii , Blumenau Mark , Fridman Mikhail , Khabarova Olga , Obridko Vladimir
Published: March 2022

We propose a new method for automatic detection of solar magnetic tornadoes based on computer vision methods. Magnetic tornadoes are magneto-plasma structures with a swirling magnetic field in the solar corona, and there is also evidence for the rotation of plasma in them. A theoretical description and numerical modeling of these objects are very difficult due to the three-dimensionality of the structures and peculiarities of their spatial and temporal dynamics [Wedemeyer-Böhm et al, 2012, Nature]. Typical sizes of magnetic tornadoes vary from 102 km up to 106 km, and their lifetime is from several minutes to many hours. So far, quite a few works are devoted to their study, and there are no accepted algorithms for detecting solar magnetic tornadoes by machine methods. An insufficient number of identified structures is one of many problems that do not allow studying physics of magnetic tornadoes and the processes associated with them. In particular, the filamentous rotating structures are well delectable only at the limb, while one can only make suppositions about their presence at the solar disk.
Our method is based on analyzing SDO/AIA images at wavelengths 171 Å, 193 Å, 211 Å and 304 Å, to which several different algorithms are applied, namely, the convolution with filters, convolutional neural network, and gradient boosting. The new technique is a combination of several approaches (transfer learning & stacking) that are widely used in various fields of data analysis. Such an approach allows detecting the structures in a short time with sufficient accuracy. As test objects, we used magnetic tornadoes previously described in the literature [e.g., Wedemeyer et al 2013, ApJ; Mghebrishvili et al. 2015 ApJ]. Our method made it possible to detect those structures, as well as to reveal previously unknown magnetic tornadoes.
Observation of solar particle events from MGNS experiment onboard BepiColombo mission, HEND experiment onboard Mars Odyssey mission, and also FREND and Liulin-MO experiments onboard TGO mission during July-October 2021
Authors: Kozyrev Alexander , Litvak Maxim , Malakhov Alexey , Mitrofanov Igor , Semkova Jordanka , Koleva Rositza , Benghin Victor , Krastev Krasimir , Matviichuk Yuri , Tomov Borislav , Maltchev Stephan , Bankov Nikolay , Shurshakov Vyacheslav , Drobyshev Sergey
Published: March 2022

This report presents the results of observations of Solar Particle Events (SPE) in July-October 2021 that have been simultaneously detected by the MGNS (Mercury Gamma-ray and Neutron Spectrometer) instrument on board the MPO spacecraft of the BepiColombo mission which is currently on a cruise phase to Mercury, as well as by science instruments that are operated in near-Mars orbit: HEND (High Energy Neutron Detector) instrument onboard Mars Odyssey mission, FREND (Fine Resolution Epithermal Neutron Detector) instrument and Liulin-MO dosimeter onboard ExoMars TGO (Trace Gas Orbiter) mission. This location of the spacecrafts, allowed for stereoscopic observation of SPEs, in addition during the period July-October 2021 Mars is on the opposite side of the Sun from Earth, when it is difficult to observe these SPEs by instruments on a near-Earth group of spacecrafts for Solar monitoring. The report will present an analysis of the energy spectra deposition and analysis of time profiles. In particular it shows the Forbush decrease of GCR in effect of the arrival of the dense solar plasma to the SPE observation locations. The MGNS, HEND and FREND instrument developed and manufactured at the Space Research Institute of the Russian Academy of Sciences and are a Russian-made and Russian-funded contribution by the Russian Federal Space Agency (ROSCOSMOS) to the BepiColombo, Mars Odyssey and ExoMars TGO missions, respectively. Liulin-MO has been developed in Space Research and Technology Institute at the Bulgarian Academy of Sciences with participation of Institute of Biomedical Problems of the Russian Academy of Sciences (Moscow) and Institute for Space Research (Moscow).

Acknowledgements

The work in Bulgaria is supported by grant KP-06-Russia 24 for bilateral projects of the National Science Fund of Bulgaria and Russian Foundation for Basic Research.
Turbulence-driven magnetic reconnection and the magnetic correlation length in collisionless plasma turbulence
Authors: Stawarz Julia E. , Eastwood Jonathan P. , Phan Tai , Gingell Imogen L. , Pyakurel Prayash S. , Shay Michael A. , Robertson Sadie L. , Russell Christopher T. , Le Contel Olivier
Published: March 2022

Observations of Earth’s magnetosheath from the Magnetospheric Multiscale (MMS) mission have provided an unprecedented opportunity to examine the detailed structure of the multitude of thin current sheets that are generated by plasma turbulence, revealing that a novel form of magnetic reconnection, which has come to be known as electron-only reconnection, can occur within magnetosheath turbulence. These electron-only reconnection events occur at thin electron-scale current sheets and have super-Alfvénic electron jets that can approach the electron Alfvén speed; however, they do not appear to have signatures of ion jets. It is thought that electron-only reconnection can occur when the length of the reconnecting current sheets along the outflow direction is short enough that the ions cannot fully couple to the newly reconnected magnetic field lines before they fully relax. In this work, we examine how the correlation length of the magnetic fluctuations in a turbulent plasma, which constrains the length of the current sheets that can be formed by the turbulence, impacts the nature of turbulence-driven magnetic reconnection. Using observations from MMS, we systematically examine 60 intervals of magnetosheath turbulence – identifying 256 small-scale reconnection events, both with and without ion jets. We demonstrate that the properties of the reconnection events transition to become more consistent with electron-only reconnection when the magnetic correlation length of the turbulence is below ~20 ion inertial lengths. We further discuss the implications of the results in the context of other turbulent plasmas by considering observations of turbulent fluctuations in the solar wind.
Pangeo for geolocating fish using biologging data
Authors: Magin Justus , Woillez Mathiew , Queric Antoine , odaka Tina
Published: March 2022

In biologging, a small device attached to an animal is used to track its behaviour and environment. This data enables biologists to gain a better understanding of its movement, its preferred habitats, and the environmental conditions it needs to thrive, all of which is essential for the future protection of natural resources. For that, it is crucial to have georeferenced data of biological processes, such as fish migration, over a spatial and temporal range.

Since it is challenging to track fish directly in the water, models have been developed to geolocate fish from the high resolution temperature and pressure time series obtained from the data storage tag. In particular, reconstructing the trajectories of seabass using the temporal temperature changes obtained from biologging devices has been studied since 2010 (https://doi.org/10.1016/j.ecolmodel.2015.10.024). These fish tracks are computed based on the likelihood of the temperature data obtained from the fish tag and reference geoscience data such as satellite observations and ocean physics model output. A high temporal and spatial resolution of the reference data plays a key role in the quality of the fish trajectories. However, the size and accessibility of these data sets as well as the computing power required to process high resolution data remain technical barriers.

As the Pangeo ecosystem has been developed  to solve such challenges in geoscience, we can take advantage of it in biologging. We use libraries such as intake, kerchunk, and fsspec to quickly load the data, xarray, pint, and dask to compute and hvplot and jupyter to display the results. The pangeo software stack enables us to easily access the data and compute high resolution fish tracks in a scalable and interactive manner. 
Comparing two fiber-optic sensing systems: Distributed Acoustic Sensing and Direct Transmission
Authors: Bowden Daniel , Fichtner Andreas , Nikas Thomas , Bogris Adonis , Lentas Konstantinos , Simos Christos , Smolinski Krystyna , Simos Iraklis , Melis Nikolaos
Published: March 2022

Distributed Acoustic Sensing (DAS) systems have gained popularity in recent years due to the dense spatial coverage of strain observations; with one fiber and one interrogator researchers can have access to thousands of strain or strain-rate observations over a region. DAS systems have a limited range, however, with usual experiments being on the order of 10’s of kilometers, owing to their reliance on weakly backscattered light. In contrast, systems that transmit light through a fiber and measure signals on the other end (or looped back) can traverse significantly longer distances (e.g., Marra et. al 2018, Zhan et. al 2021, Bogris et. al 2021), and have the added advantages of being potentially cheaper and potentially operating in parallel with active telecommunications purposes. The disadvantage of such transmission systems is that only a single measurement of strain along the entire distance is given.

During September - October 2021, we operated examples of both systems side-by-side using telecommunications fibers underneath North Athens, Greece, in collaboration with the OTE telecommunications provider. Several earthquakes were detected by both systems, and we compare observations from both. The DAS system is a Silixa iDAS Interrogator measuring strain-rate. The newly designed transmission system relies on interferometric use of microwave frequency dissemination; signals sent along the fiber and back in a closed loop are compared to what was sent to measure phase differences (Bogris et. al 2021). We find that both systems are successful in sensing earthquakes and agree remarkably well when DAS signals are integrated over the length of the cable to properly mimic the transmission observations.

The direct transmission system, however, may not be as intuitive to interpret as an integral of displacement ground motions along the fiber. We discuss both theoretical and data-driven examples of how the observed phases depend on the curvature of a given length of fiber, and describe how asymmetries in the fiber’s index of refraction play a role in producing observed signals. Such an understanding is crucial if one is to properly interpret the signals from such a system (e.g., especially very long trans-oceanic cables). Given a full theoretical framework, we also discuss a strategy for seismic tomography given such a system: with a very long fiber, the spatial sensitivity should evolve over time as seismic signals reach different sections.
Forecasting shortages in staple crop production in Burkina Faso to inform early warning systems 
Authors: Laudien Rahel , Gornott Christoph , Schauberger Bernhard , Waid Jillian
Published: March 2022

Almost half of the Burkinabe population is moderately or severely affected by food insecurity. Due to ongoing armed conflicts and the outbreak of COVID-19 in 2020 negatively affecting households’ income and access to markets, the number of food insecure people is expected to increase. Moreover, climate change further jeopardizes domestic food production and thus food security. Early warning systems can provide information about the expected harvest, which allows governments to adjust food imports in case of expected harvest losses or ask for external food assistance. Thus, early warning systems can contribute to increased food security.

In this session, we would like to discuss how a forecast of staple crop production can inform early warning systems of food security. Based on a statistical crop model, we provide a within-season forecast of crop production for maize, sorghum and millet in Burkina Faso. Moreover, we compare actually supplied calories with those usually consumed from staple crops, allowing us to provide early information on shortages in domestic cereal production on the national level.

Results show that despite sufficient domestic cereal production from maize, sorghum and millet on average, a considerable level of food insecurity prevails for large parts of the population. This highlights the importance of a comprehensive assessment of all dimensions of food security to rapidly develop counteractions for looming food crises.
A gridded wind speed observation product using artificial intelligence for Eastern Iberian Peninsula
Authors: Khorchani Makki , Zhou Lihong , Azorin-Molina Cesar , Jiang Xin , Bedoya-Valestt Shalenys , Utrabo-Carazo Eduardo , Andres-Martin Miguel , Zhang Gangfeng , Zeng Zhenzhong
Published: March 2022

Abstract: The demand for high spatially distributed wind speed data is substantially increasing during the last decades. This increase stems from its crucial role for climate change studies and many socioeconomic and environmental issues, e.g., wind power generation. However, observed wind speed records from weather stations do not cover this demand due to their coarse spatial resolution and inhomogeneous time scales, limiting the possibility of developing accurate gridded wind speed products using traditional geostatistical gridding methods. Moreover, wind speed from reanalyses and climate simulations does not accurately reproduce observed wind speed and gusts at regional scales. For instance, it lacks capturing the multidecadal variability of wind speed, e.g., the stilling (decline in winds) vs. the reversal (increase in winds) phenomena.

Artificial Intelligence is a powerful tool that can overcome these data availability and quality limitations of wind observations. In this study, we apply artificial intelligence to reconstruct wind speed data from in situ weather observations in the Eastern Iberian Peninsula, focusing on the Valencia region. The generated time series are then implemented to develop a high spatial resolution gridded wind speed observations at a regional scale. This new gridded wind speed dataset will allow computing, e.g., wind indices as a climate service for multiple socioeconomic and environmental sectors.

Keywords: wind speed; time series reconstruction; machine learning; gridded wind speed product
Survey of EDR-associated Magnetopause Flux Ropes with MMS
Authors: Robertson Sadie , Eastwood Jonathan , Stawarz Julia , Russell Christopher , Giles Barbara , Burch James
Published: March 2022

Flux ropes are twisted magnetic field structures produced during magnetic reconnection. They are thought to be important for energy transport and particle acceleration and are commonly observed throughout space plasma environments, including at the Earth’s magnetopause. Flux Transfer Events (FTEs), which typically contain flux ropes, have been observed to grow in size and flux content as they are convected over the magnetopause and into the magnetotail, contributing to flux transport in the Dungey cycle. More recently, small-scale flux ropes have been observed inside the Electron Diffusion Region (EDR) during magnetopause reconnection. 

In this study, we investigate the link between the EDR and flux ropes, presenting a survey of 245 flux ropes observed by the Magnetospheric Multiscale (MMS) mission on days during which the spacecraft also encountered the EDR. MMS measures the thermal electron and ion 3D distributions at 30 msec and 150 msec time resolution, respectively, and at spacecraft separations down to a few kilometres allowing the study of such electron-scale phenomena. We find that flux ropes are more likely to be observed closer to the EDR, and that flux ropes observed closer to the EDR tend to have greater axial magnetic field strength and therefore greater flux content. We suggest that we could be sampling a subset of flux ropes that are recently formed by the EDR and discuss how this impacts current theories for flux rope evolution on the magnetopause.
A data-driven approach to understanding global controls of cloud radiative effects
Authors: Andersen Hendrik , Cermak Jan
Published: March 2022

In this contribution, statistical and machine learning techniques are applied to quantify the response of clouds to changes in environmental factors.

Clouds play a key role for the Earth’s energy balance; however, their response to climatic and anthropogenic aerosol emission changes is not clear, yet. Here, 20 years of satellite cloud observations are analyzed together with reanalysis data sets in multivariate-regression and machine-learning approaches to quantitatively link the variability of observed cloud radiative effects to changes in environmental factors, or cloud-controlling factors (CCFs). In this data-driven approach, a large number of CCFs, including aerosol proxies, are used as predictors at a large spatial and temporal scale typical of CCF analyses. The analysis reveals distinct regional patterns of CCF importance for shortwave and longwave cloud radiative effects. In stratocumulus cloud regions, the main controls of shortwave CRE are the sea surface temperature and the estimated inversion strength, but also zonal winds in the lower free troposphere are relevant controls of CRE. Aerosol proxies are shown to be most important for shortwave CRE in the regions of stratocumulus to cumulus transition. Future analyses of interactions between different CCFs and comparisons to global climate models are outlined.
Network Design for a Cost-Effective Atmospheric Methane Measurement Network over India
Authors: Elias Eldho , Pillai Dhanyalekshmi , Marshall Julia , Totsche Kai Uwe , Gerbig Christoph
Published: March 2022

Studies have shown that the uncertainty of methane emission estimates over India is as high as 40-60%, largely due to the lack of observations. In India, measurements are limited to a few locations, with the majority of them being flask measurement stations. The observational constraint of the measurements could be greatly improved with the development of a network of continuous measurement stations at well-chosen locations. For this study, we have designed an atmospheric methane measurement network for India using transport modeling techniques and a scaling-factor-based inversion approach. A network optimization algorithm selects the combination of observation locations that gives the most uncertainty reduction in the estimates of posterior methane emission fluxes over India. The backbone of this study is a simple analytical inversion setup that utilizes the STILT (Stochastic Time Inverted Lagrangian Transport) model, a sectorial emission model based on EDGAR, as well as fluxes from wetlands and biomass burning. The state space of the inversion consists of monthly emissions, separated by sector, aggregated spatially to the level of political states.

The challenge in network design is to formulate an appropriate target quantity, which the network will be optimized to constrain. Using the annual total emissions as the single target results in a network that will optimally constrain the largest sources, irrespective of their spatial location or the seasonality of the source. Thus, we also included other targets, such as political-state-level emissions, sectoral emissions, and seasonality. For the study, we used a base network of existing stations (“base”) and added further stations from a candidate set (“extended”) on the basis of the incremental uncertainty reduction they provide. We found that more measurement stations along the Indo-Gangetic Plains and North-Eastern India are required. An optimized network was also designed from scratch using the same strategy and it was found to yield similar uncertainty reduction compared to the “base” + “extended” network despite having fewer stations. The effectiveness of the optimal network and the base network in reducing the uncertainties of the different emission categories is assessed and discussed.
Circulation, stratification and salt dispersion in a former estuary after reintroduction of seawater inflow to improve fish migration
Authors: Kranenburg Wouter , Tiessen Meinard , Blaas Meinte , van Veen Nathalie
Published: March 2022

The Haringvliet is a former estuary in the Rhine-Meuse Delta. Since 1970, seaward outflow is regulated with floodgates, while seawater is kept out. To improve fish migration and the ecological quality of the Rhine-Meuse system, limited seawater inflow during flood has been reintroduced again in 2018. The incoming salt water progresses through the former tidal channels, arrives in deep pits and is partially flushed out again by the outflow, especially during high river discharge. However, the remaining salt water can gradually spread through the system due to wind-induced mixing and circulations, especially when the gates are closed also for outflow during low river discharge. As this can threaten fresh water intakes, inflow, flushing and dispersion of salt need to be well understood and carefully managed.

In this study we analyse velocity measurements from ADCPs at two former tidal channels in the Haringvliet, together with salinity time series and profiles at multiple locations. The salinity profiles show that the system tends to be strongly stratified. Using the ADCP backscatter, we estimated the time development of the interface level to relate this to the local velocity, floodgate discharge and wind. For peak discharges and low wind speed, the velocities show a clear relation with the discharge and the interface can lower abruptly. However, for lower discharges and higher wind speed, the relations are less clear, and the profiles are highly affected by the wind. In case of wind but closed sluices, flow against the wind was found for wind in the systems longitudinal direction. We explain this from the large area of (former) shoals, leading to flow with the wind in shallow parts and against the wind in deep parts due to a local imbalance between stress divergence and pressure gradient. This turns out to be an important driver of landward salt transport, as increased salt concentrations were found at landward locations for seaward wind. Next to that, indications were found of exchange between former tidal channels and transport over sills due to wind driven tilting of the salinity interface.

Enhanced understanding of the salt transport dynamics in this former estuary after reintroduction of limited seawater inflow is an essential element to manage this system, protect the fresh water availability and keep the confidence of critical stakeholders, which is essential for the success of this ecosystem improvement program.