bluuebunny/crossref_metadata_2025 huggingface dataset:
The LUE software framework: develop scalable global hydrological models without having to think about high-performance computing
Authors: de Jong Kor , Karssenberg Derek
Published: February 2023

High-resolution continental scale hydrological modelling often requires distributed computing to solve the model equations. Developing and maintaining these models is an enormous challenge as current approaches require knowledge about parallel and distributed computing. A solution to the problem followed here is the development of a modelling framework that deals with parallelization of model equations under the hood. Using such a framework allows hydrologists who are not familiar with low level software development and high-performance computing to develop models.Our modelling framework, called LUE (de Jong et al. 2022, 2021), allows models that are large in terms of data set size and the number of calculations used, to use all hardware available to them efficiently. LUE models can be written in Python or C++, and can be executed unchanged on laptops and computer clusters.In the implementation of LUE model operations we use the asynchronous many-tasks (AMT) approach, as implemented in the HPX C++ library. This makes it possible for model developers to express their models using simple algebraic expressions, while all details related to scheduling computations on parallel and distributed hardware are hidden from view. Executing LUE models results in a relative large collection of tasks that are ready to be scheduled for execution on the available hardware. This, in turn, results in models that are finished sooner and that can use additional hardware efficiently, automatically.We are currently busy porting the PyCatch modelling suite (Lana-Renault and Karssenberg 2013), which is an integrated set of process-based hydrological and soil-vegetation models, to LUE. PyCatch is implemented in terms of generic modelling operations inspired by map algebra (local, focal, zonal, global operations) and flow routing operations like flow accumulation and the kinematic wave.In our presentation we will further explain the LUE modelling framework, including the operations that are specifically targeted at hydrological modelling, and show results of applying the PyCatch model to Africa at 3 arc-second resolution (~90 m at the equator) using the MERIT Hydro high resolution raster data set.Referencesde Jong, K., D. Panja, D. Karssenberg, and M. van Kreveld. 2022. “Scalability and Composability of Flow Accumulation Algorithms Based on AsynchronousMany-Tasks.” Computers & Geosciences. https://doi.org/10.1016/j.cageo.2022.105083.de Jong, K., D. Panja, M. van Kreveld, and D. Karssenberg. 2021. “An Environmental Modelling Framework Based on Asynchronous Many-Tasks: Scalability and Usability.” Environmental Modelling & Software. https://doi.org/10.1016/j.envsoft.2021.104998.Lana-Renault, N., and D. Karssenberg. 2013. “PyCatch: Component Based Hydrological Catchment Modelling.” Cuadernos de Investigación Geográfa. https://doi.org/10.18172/cig.1993.
Geomagnetic characteristics of submarine volcanic area off the coast of northern Taiwan
Authors: Lo Chung-Liang , Hsu Shu-Kun , Lin Shiao-Shan , Tsai Ching-Hui , Doo Wen-Bin , Chen Song-Chuen , Su Pin-Ju
Published: February 2023

As an active mountain building, Taiwan Island is deduced from the oblique collision between the Eurasian and the Philippine Sea plate, and its northern part and offshore region are under post-collision collapse. The magmatism induced from the post-collision collapse therefore distributes in the northern Taiwan and its offshore area. A series of submarine volcanoes and igneous rock isles are rooted in the area. For investigation of the volcanic and igneous arrangement, we have collected the magnetic data over the past few decades to combine and compile a map of regional magnetic anomalies. A pronounced magnetic high largely dominates the area of most submarine volcanoes and extends eastward, while the adjacent areas to the north and west are lower. To better understand the magnetic features for the submarine volcanic area, the magnetization for an equivalent magnetic layer thickness was calculated. The result shows that a high magnetization concentrated on the SV7 and extends northwestward that could be a magnetic dipole combining with its northeastern low part. To the southward, the submarine volcanoes SV1, SV3-SV6 locate between this high and another low magnetization. We also applied the enhanced analytic signal technique from the same magnetic data to evaluate the magnetic source strength distribution. Except for the SV2, SV5 and SV6, the 0th degree of enhanced analytical signal shows that most signal high concentrated on the submarine volcanic areas. For higher degree of enhanced analytical signal, the highest magnitude focus on the Ks and SV1, and PV, SV3 and SV4 are slightly minor.
The role of anchor observations in disentangling observation and model bias corrections in 4DVar
Authors: Francis Devon , Fowler Alison , Lawless Amos , Migliorini Stefano , Eyre John
Published: February 2023

Data assimilation theory relies on the assumption that the background, model, and observations are unbiased. However, this is often not the case and, if biases are left uncorrected, this can cause significant systematic errors in the analysis. When bias is only present in the observations, Variational Bias Correction (VarBC) can correct for observation bias, and when bias is only present in the model, Weak-Constraint 4D Variational Assimilation (WC4DVar) can correct for model bias. However, when both observation and model biases are present, it can be very difficult to understand how the different bias correction methods interact, and the role of anchor (unbiased) observations becomes crucial for providing a frame of reference from which the biases may be estimated. This work presents a systematic study of the properties of the network of anchor observations needed to disentangle between model and observation biases when correcting for one or both types of bias in 4DVar.We extend the theory of VarBC and WC4DVar to include both biased and anchor observations, to find that the precision and timing of the anchor observations are important in reducing the contamination of model/observation bias in the correction of observation/model bias. We show that anchor observations have the biggest impact in reducing the contamination of bias when they are later in the assimilation window than the biased observations, as such, operational systems that rely on anchor observations that are earlier in the window will be more susceptible to the contamination of model and/or observation biases. We also compare the role of anchor observations when VarBC/WC4DVar/both are used in the presence of both observation and model biases. We find that the ability of VarBC to effectively correct for observation bias when model bias is present, is very dependent on precise anchor observations, whereas correcting model bias with WC4DVar or correcting for both biases performs reasonably well regardless of the precision of anchor observations (although more precise anchor observations reduces the bias in the state analysis compared with less precise anchor observations for all three cases). This demonstrates that, when it is not possible to use anchor observations, it may be better to correct for both observation and model biases, rather than relying on only one bias correction technique. We demonstrate these results in a series of idealised numerical experiments that use the Lorenz 96 model as a simplified model of the atmosphere.
Determining the radiative and hydrologic controls on the diurnal air-temperature range using the thermodynamic limit of maximum power
Authors: Ghausi Sarosh Alam , McColl Kaighin , Kleidon Axel
Published: February 2023

The diurnal air temperature range (DTR) is strongly shaped by solar radiation but is modulated by hydrologic cycling through changes in atmospheric (clouds) and land-surface (evaporation) characteristics. Here, we aim to determine the distinct patterns in DTR over dry and wet periods and identify their respective controls. To do this, we develop a simple energy balance model that constrains the land-atmosphere exchange using the thermodynamic limit of maximum power. In this framework, we explicitly account for changes in radiative conditions due to clouds and changes in boundary layer heat storage associated with surface water limitation, both of which affect the maximum power limit. Using observations of radiative forcings and surface evaporation, our model predicts DTR reasonably well across 81 FLUXNET sites in North America, Europe, and Australia. We show that DTR is primarily shaped by the trade-off between the heat gain due to solar absorption and heat lost at the surface due to evaporation. Radiation remains a primary control on DTR over very dry and wet conditions where evaporation is either close to zero or limited by available energy. Over these regions, changes in DTR are strongly modulated by clouds which alters the radiative conditions. DTR becomes coupled to the land surface during the transition regime where changes in surface water availability directly control the evaporation rates. Over these regions, increased soil moisture results in more evaporation and reduced DTR. These responses were consistent in both, observations and maximum power estimates. We then apply our framework to quantify the response of DTR to global warming. Our model projects a decrease in DTR by 0.18K for a 1K rise in global temperature, which is consistent with the current observed response. Our findings imply that the predominant controls on DTR are set by clouds and evaporation as they directly modulate the diurnal heating of the lower atmosphere and can be further altered by increased greenhouse forcing.
Assessing seasonal meteorological and hydrological forecasts across South Korea
Authors: Lee Yongshin , Peñuela-Fernandez Andres , Pianosi Francesca , Rico-Ramirez Miguel
Published: February 2023

Due to the intensified impact of climate change, the intensity and severity of catastrophic droughts is increasing all over the world. South Korea had also suffered from extreme droughts, including a recent a drought that prolonged from 2013 to 2015 and caused nation-wide crop failures. As one of the measures to anticipate droughts and mitigate damages, past studies have evaluated the use of seasonal forecasts in other regions. However, few studies have focussed the assessment at catchment-scale, which is more suitable for practical water management, and no studies were found on the assessment of seasonal forecasts over South Korea.Firstly, we assessed the skill of Seasonal Precipitation Forecasts (SPFs) over the 20 catchments in South Korea where the largest reservoirs are located, over the period 2011 to 2020. Ensemble SPFs from 4 weather forecasting centres (ECMWF, UK Met Office, Météo France and DWD) were evaluated, and the skill quantified using the Continuous Ranked Probability Skill Score (CRPSS). We analysed how the skill of the seasonal meteorological forecasts varies across the seasons and years, before and after bias correction, and if the skill can be linked to catchments characteristics. In doing so, we developed a methodology and a Python package to implement it, which is freely available for future applications to other regions (https://github.com/uobwatergroup/seaform.git). The results showed that amongst the four forecasting centres, SPFs by ECMWF were the most skilful in South Korea. In particular, they generally outperformed climatology for up to 2 months of lead time and during the Wet season of drier years for all the lead times. We also found that linear bias correction is useful to correct systematic seasonal biases and there is no significant correlation between the catchment characteristics and forecast skill. Additionally, we investigated the possibility of anticipating dry years from ENSO indices and the forecasts themselves, but we found no significant link.Secondly, we looked at how skill in seasonal meteorological forecasts propagates into the skill of hydrological forecasts (SHFs). We used the lumped hydrological Tank model to generate ensembles of reservoir inflow from ECMWF’s seasonal forecasts data (precipitation, Evapotranspiration and temperature). Again, we quantified the skill (CRPSS) of SHFs at different lead times, seasons and in wet and dry year. The results showed that the skill of SHFs is highly dependent on the skill of SPFs, and it mimics the seasonal and annual (dry and wet years) features of precipitation forecasts. We also tested 4 different types of processing methods (raw, pre-processing, post-processing, pre/post-processing) found that pre-processing method which corrects bias of weather forcings is the most useful to improve forecast skill.
Earthquake source parameters in the Zagros region (Iran) from the time of evolutionary P-wave Displacement
Authors: Nazeri Sahar , Abdi Fatemeh , Ismail Amir , Rahimi Habib , Zollo Aldo
Published: February 2023

The rupture process of the recent moderate-to-large earthquakes in the longest seismic sector in Iran's plateau, the Zagros area, has been modeled using the strong motion data provided by the Iranian Building and Housing Research Center (BHRC). The selected dataset includes the largest and deadliest seismic event, the 2017 Mw 7.3, Sarpol-e Zahab earthquake. The earthquake source parameters (moment magnitude, source duration, rupture dimension, and average stress drop) are determined by implementing a parametric modeling technique in the time domain based on the time evolution of the P-wave displacement signals. The seismic source parameters are calculated from simulated trapezoidal and triangular moment-rate functions assuming the unilateral rectangle and circular crack models, respectively, where the rupture propagates at a constant velocity as a fraction (90%) of the average shear-wave velocity in the medium. The anelastic attenuation effect assuming the independent frequency-Q parameter ranging from 50 to 200 is accounted for by a post-processing procedure that retrieved the observed moment-rate triangular shape. Hence, the average stress drop with different varies between <Δ𝜎>=1.50 (1.14−1.95) and <Δ𝜎>=0.90 (0.71−1.14) MPa. Assuming a circular rupture model for Sarpol-e-Zahab, we estimate a moment magnitude of 7, rupture duration of 7 seconds, source radius of 16 km, and statistical stress drop of about 3.5 MPa. Alternatively, a unilateral rupture model calculates the fault length and width at 45 and 16 km, with a lower stress drop of 2 MPa.
Dynamic response of an elliptic cylinder inclusion with imperfect interfaces subjected to plane SH wave
Authors: Ming Tao , Hao Luo , Rui Zhao , Gongliang Xiang
Published: February 2023

Underground chambers or tunnels often contain inclusions, the interface between the inclusion and the surrounding rock is not always perfect, which influences stress wave propagation. In this study, the spring model and Ricker wavelet were adopted to represent the imperfect interface and transient seismic wave. Based on the wave function expansion method and Fourier transform, an analytical formula for the dynamic stress concentration factor (DSCF) for an elliptical inclusion with imperfect interfaces in infinite space subjected to a plane SH-wave was determined. The theoretical solution was verified via numerical simulations using the LS-DYNA software, and the results were analyzed. The effects of the wave number (k), radial coordinate (ξ), stiffness parameter (β), and differences in material properties on the dynamic response were evaluated. The numerical results revealed that the maximum DSCF always occurred at both ends of the elliptical minor axis, and the transient DSCF was generally a factor of 2-3 greater than the steady-state DSCF. Changes in k and ξ led to variations in the DSCF value and spatial distribution, changes in β resulted only in variations in the DSCF value, and lower values of ωp and β led to a greater DSCF under the same parameter conditions. In addition, the differences in material properties between the medium and inclusion significantly affected the variation characteristics of the DSCF with k and ξ.
Schrodinger’s queers: Are they, or aren’t they?
Authors: Horswell Michael
Published: February 2023

STEM disciplines have a bad reputation for gender and sexual minority (GSM) inclusion. Both large scale quantitative surveys and more personally focussed qualitative research have shown that most GSM people in STEM disciplines modify, restrict, or manage their self-expression in professional contexts. In educational institutions, relationships are potentially more fraught as the interpersonal complexities of pedagogic interactions make things yet more difficult.This paper will reflect on a range of contextual literature as a way positioning the personal stories of seven GSM academics at a British university. Undertaken over a period of two years, the reported research involved a series of open discussions with teaching academics across a range of STEM disciplines. Surprisingly, even in the context of a liberal, higher education context, all collaborators adopted impression management strategies in their relationships with colleagues, and noticeably more constrained relationships with students.The paper concludes with preliminary observations about the impact of institutional equality and diversity policies as a way of promoting an open, and inclusive professional context, and considers the implications of the research for student-facing STEM academics.
Grain growth kinetics of bridgmanite under topmost lower-mantle
Authors: Fei Hongzhan , Faul Ulrich , Ballmer Maxim , Walte Nicolas , Katsura Tomoo
Published: February 2023

The absence of seismic anisotropy in most regions of the lower mantle suggests that diffusion creep may be the dominant mechanism in the lower mantle. Because the diffusion-creep rate is inversely proportional to the 2~3 power of grain size, knowledge of the grain-growth kinetics is crucial for studying lower-mantle dynamics. For these reasons, this study determined the grain-growth kinetics of bridgmanite at a pressure of 27 GPa using advanced multi-anvil techniques.We first measured the grain sizes of bridgmanite in an olivine bulk composition with various annealing durations at 2200 K. The results were fitted to an equation dn – d0n = kt, where d and d0 are the final and initial grain sizes, respectively, n is the grain-size exponent, t is the annealing duration, and k is the growth-rate constant. This fitting yielded n = 5.2 ± 0.3, which is much smaller than given by a previous study [Yamazaki et al., 1996], n = 10.6 ± 1.1. This discrepancy may be because Yamazaki et al.’s [1996] olivine starting material may have contained adhesive water, which enhanced grain growth at the beginning of annealing. We then conducted runs at various temperatures, yielding the activation energy of 260 ± 20 kJ/mol. These results suggest that the bridgmanite grain sizes over 0.1 – 1 Gyr should have grain sizes of 150-230 μm, which is one order of magnitude larger than Yamazaki et al.’s [2006] estimation. Consequently, the lower mantle should be much harder than previously considered.Furthermore, we measured the grain-growth kinetics as a function of the fraction of coexisting ferropericlase. Although the grain-growth kinetics is almost independent of the ferropericlase fraction down to 20 vol.%, it rapidly increases with decreasing ferropericlase fraction at lower fractions. Over 0.1~4.5 Gyr, the bridgmanite grain sizes in pure-bridgmanite rock should be 2 ~ 3 orders of magnitude larger than those coexisting with 20 vol.% of ferropericlase. These results suggest that pure-bridgmanite rock has 4 ~ 9 orders of magnitude lower flow rates than pyrolite if the diffusion creep is dominant. Since the diffusion creep rate in pure-bridgmanite rock is so low, the dislocation creep should dominate in pure-bridgmanite rock. We estimated that the pure-bridgmanite rock should have 1 ~ 2.5 orders of magnitude more viscous than pyrolite if the stress condition is 0.1~0.5 MPa in the lower mantle. This variation may interpret the viscosity variation in the lower mantle inferred from the geoid analysis [Rudolph et al., 2015], subduction speed [van der Meer et al., 2018], and plume morphology [French & Romaniwicz, 2016].
A stochastic eco-hydrological model reveals the impact of active stream dynamics and connectivity on metapopulation
Authors: Bertassello Leonardo Enrico , Durighetto Nicola , Botter Gianluca
Published: February 2023

The active portion of river networks varies in time thanks to event-based and seasonal expansion-retraction cycles that mimic the unstradiness of the underlying climatic conditions. These rivers, usually referred to as temporary streams, constitute a major fraction of the global river network. Temporary streams provide a unique contribution to riverine ecosystems, as they host unique habitats that promote biodiversity. Nonetheless, the impacts of network dynamics on ecological processes and ecosystem services are not fully understood. In this contribution, we present a stochastic framework for the coupled simulation of active stream dynamics and the related occupancy of a metapopulation. The framework combines a stochastic model for the generation of synthetic streamflow time series with the hierarchical structuring of river network dynamics, to enable the simulation of the full spatio-temporal dynamics of the active portion of the stream network under a wide range of climatic settings. The hierarchical nature of stream dynamics - which postulates that during wetting nodes are  activated sequentially from the most to the least persistent, and deactivated in reverse order during drying - represents a key feature of the approach, as it enables a clear separation between the spatial and temporal dimensions of the problem. The framework is complemented with a stochastic dynamic metapopulation model that simulates the occupancy of a metapopulation on the simulated stream. Our results show that stream intermittency negatively impacts the average occupancy and the probability of extinction of the focus metapopulation. Likewise, the spatial correlation of flow persistency along the network bears a sizable impact on the mean network connectivity and occupancy. This effect is particularly important in drier climates, where most of the network undergoes sporadic and flashy activations, and species dispersal is regularly inhibited by river fragmentation. This approach offers a robust but parsimonious mathematical framework for the synthetic simulation of stream network dynamics under a broad range of climatic and morphological conditions, providing useful insights on stream expansion and retraction in its ecological significance.
Land plant evolution and volcanism led to the Late Devonian mass extinction
Authors: Filippelli Gabriel , Smart Matthew , Gilhooly William , Ozaki Kazumu , Reinhard Christopher , Whiteside Jessica , Marshall John
Published: February 2023

The evolution of land plants in terrestrial environments brought about one of the most dramatic shifts in the history of the Earth system — the birth of modern soils — and likely stimulated massive changes in marine biogeochemistry and climate. In particular, multiple marine mass extinctions characterized by widespread anoxia, including the Late Devonian mass extinction around 375 million years ago (Ma), may have been linked to terrestrial nutrient release driven by newly-rooted landscapes. Here, we use recently generated constraints from Earth’s lacustrine rock record as variable inputs in an Earth system model of the coupled C-N-P-O2-S biogeochemical cycles in order to evaluate whether recorded changes to phosphorus fluxes would be adequate to sustain Devonian marine biogeochemical perturbations and extinction dynamics. Results show that globally scaled riverine phosphorus export during the Late Devonian mass extinction generates widespread marine anoxia and produces carbon isotope, temperature, oxygen, and carbon dioxide perturbations generally consistent with the geologic record. Similar results for a competing extinction mechanism, large scale volcanism, suggest the Late Devonian mass extinction was likely multifaceted with both land plants and volcanism as contributing factors.
deteCtion and threAts of maRinE Heat waves (CAREHeat) ESA project: How to better characterize Marine Heatwaves ?
Authors: Verbrugge Nathalie , Pisano Andrea , Augot Jérémy , Greiner Eric , Landolfi Angela , Leonelli Francesca , Da Toma Vincenzo , Organelli Emanuele , Marullo Salvatore , Santoleri Rosalia
Published: February 2023

The ongoing project “deteCtion and threAts of maRinE Heat waves – CAREHeat”, funded by ESA in the framework of the Ocean Health initiative, aims at improving the current Marine Heatwaves (MHW) detection and characterization methodologies at the sea surface, at analysing MHW vertical propagation through the development of 4D temperature fields by using Machine Learning approaches, at providing a global atlas of MHW at the sea surface, at advancing the understanding of the physical processes involved in MHW development and at assessing the MHW impact on marine Ecosystems and Biogeochemistry.  

This presentation will focus on the first phase of the project. The mostly used MHW detection method (Hobday approach) has been revisited by carrying out sensitivity studies on different threshold parameters such as the choice of the percentile threshold and the minimum duration of the events. Specific work has also been done to investigate the impact of sea surface temperature (SST) trends and prominent climate modes, as El Nino Southern Oscillation (ENSO), in order to disentangle the slow-varying SST component and quasi-periodic oscillations from the abrubt changes that are characteristics of these extreme events . Many metrics are provided along with the global atlas to help the characterization of these events. In parallel with this work, a machine learning approach based on observations has been used to reconstruct a 4D temperature field from the surface up to 300-m depth and MHWs have been estimated. Subsurface MHWs can also impact ecosystems and phase shifts with the surface events can be observed. This product helps to analyse this propagation in depth.  

The work is focused on three areas of interest: the tropical Pacific, the western Mediterranean, the Madeira Island region. In these regions, the main outcomes of the 2D and 4D analysis will be presented 

Please visit the CAREHeat website (www.careheat.org) and follow us on Twitter (@ careheat_) to stay up to date about the project research and results 
The efflorescence-deliquescence behavior of saliva droplets and its implication for viability of airborne microorganisms
Authors: Meng Yue , Dresch Thomas , Duft Denis , Kiselev Alexei , Leisner Thomas
Published: February 2023

The aerosol-based transport of viruses and bacteria through the transmission of aerosolized expiratory secretions is one of the main routes for the spreading of infectious diseases such as SARS-CoV-2. A number of studies have confirmed that environmental factors such as temperature and relative humidity can affect the inactivation and transmission of respiratory pathogens. However, there remain significant uncertainties in understanding aerosol micro-physics occurring under different environmental conditions to quantify the survival of microorganisms carried by aerosols. Here we study the size and phase changes of levitated saliva droplets composed of various salts and mucin under well-defined atmospheric conditions. An electrodynamic balance (EDB) is utilized for recording the evaporation and condensation kinetics of single, levitated saliva droplets with a time resolution of seconds. Efflorescence and deliquescence behaviors of droplets are monitored using light scattering and Mie theory. Compared with pure water droplets, a saliva droplet remains stably levitated for hours when the droplet approaches crystallization having reached a final size during evaporation. The morphology of crystallized particles will be imaged using a scanning electron microscope (SEM). The organic-based phase is expected to shield pathogens from inactivation by forming a solid or semisolid shell hindering the diffusion of solutes. This work highlights the importance of accounting for changes in the micro-environment of aerosols undergoing evaporation and condensation in a realistic environment which is needed to study the viability of airborne viruses and other microorganisms.
Impact of methane abundance on storm formation on Uranus & Neptune, revealed by a cloud-resolving model
Authors: Clement Noe , Leconte Jeremy , Spiga Aymeric , Guerlet Sandrine , Milcareck Gwenael , Selsis Franck
Published: February 2023

Despite the weak solar flux received by the ice giant planets, the storm activity of their atmospheres is intense. What is then the phenomenon responsible for this activity?

On Uranus and Neptune, a notable property draws attention: unlike the Earth, the species able to condense in the atmospheres of ice giants, methane in particular, are heavier than the ambient air, essentially hydrogen. This property makes convection difficult to start.

Convection in these atmospheres should therefore be a regime of strong intermittence where convective energy can be stored for a long time before being released in short episodes.

Our hypothesis is that this regime is at the origin of intense storms.

To study this hypothesis, we use a "cloud-resolving" model. This model is built from a dynamical core (The Weather Research and Forecasting model) solving the equations of motion, that has been initially developed for terrestrial applications and already adapted for simulations on Mars and Venus, coupled to independent physical parameterizations such as radiative transfer and micro-physics. The high resolution of the model grid can allow us to highlight moist atmospheric convection, by resolving cloud formation and dissipation.

Having successfully implemented the methane cycle in this model, we will present results from our 3D simulations, which reveal the impact of the methane cycle in tropospheric convection on Uranus & Neptune, having a special look at the methane abundance, that vary at different latitudes, and how it affects storms frequencies and intensities.
Fe in the inner coma of comet 67P/Churyumov-Gerasimenko: a complete mission overview from Rosetta DFMS mass spectra
Authors: Dhooghe Frederik , De Keyser Johan , Hänni Nora , Altwegg Kathrin , Cessateur Gaël , Jehin Emmanuel , Maggiolo Romain , Rubin Martin , Wurz Peter
Published: February 2023

Manfroid et al. 2021 reported on the ubiquitous presence of iron and nickel in cometary atmospheres even when comets are far from the Sun. Rubin et al. 2022 presented a search for refractory elements in the gas phase of comet 67P, including Fe. These authors reported two 20 s mass spectra from DFMS on board Rosetta during the 26-29 July 2015 period close to perihelion, when 56Fe was detected. They concluded that Fe is not very abundant in the gas phase in the inner coma.

This contribution presents the results of a systematic search for 56Fe in DFMS spectra for the complete Rosetta mission. The analysis sheds further light on how commonly Fe is detected in the inner coma.
Cyanobacteria blooms in the Baltic Sea
Authors: Löptien Ulrike , Dietze Heiner , Munkes Britta , Hordoir Robinson , Renz Matthias
Published: February 2023

In the Baltic Sea, cyanobacteria regularly form massive blooms in late summer. These blooms can produce toxins and have the potential to counteract management efforts to limit eutrophication because they add bioavailable nitrogen (fixed from the atmosphere) to an already over-fertilized system. Despite their critical role and substantial research progress, the controls on cyanobacteria are still not comprehensively understood. This can limit the accuracy of model-based projections. Our study adds to the ongoing discussion by providing a comparison of existing contemporary model formulations. This comparison is supplemented by a unique combination of satellite estimates of cyanobacteria blooms, in-situ nutrient observations and output of a high-resolution general ocean circulation model (MOMBA). We retrace bloom origins and conditions by calculating the trajectories of respective water parcels backwards in time. In an attempt to identify drivers of bloom development, we find that blooms originate and manifest themselves predominantly offshore. Potential implications for contemporary modelling approaches are discussed. 
How to discriminate between area-source models for probabilistic seismic hazard assessment in a more objective manner?
Authors: Duverger Clara , Keller Merlin , Senfaute Gloria
Published: February 2023

We propose a methodology to assist in the selection or definition of weights for components of seismic hazard models, which are combinations of seismic source models and ground motion models, in the context of probabilistic seismic hazard assessment (PSHA). The methodology uses Bayes's theory by optimally exploiting available observations that are the seismic catalogues and accelerometric databases. When compared to the current method of calculation, the proposed approach, simple to implement, allows a more exhaustive use of the data and discriminates between inputs without expert judgements to weigh branches of the PSHA logic tree.We implement the proposed methodology in a Python package called Phebus to process the seismic source models (the first of the two main ingredients of the seismic hazard model) as a first step. The main purpose of this package is to estimate earthquake recurrence parameters and confidence intervals using a full Bayesian approach, and perform a Bayesian model averaging (BMA) amongst multiple seismic source models. More particularly, we focused our study on area-source models, which consist of subdivisions of a particular region of interest into zones that are assumed homogeneous in terms of seismic activity rate, and that are systematically used in PSHA calculations for low-to-moderate seismic regions. We conducted sensitivity analyses on the selection performances and the adjustments performances of recurrence parameters for simplistic toy models against a synthetic model-generated seismicity catalogue. We also illustrate the application of Phebus to the metropolitan France, a low-strain region, where at least four national, competitive and published area-source models are used by engineers and researchers for seismic hazard evaluation.
Detections of a 6-year cycle in the Earth system
Authors: Pfeffer Julia , Cazenave Anny , Rosat Séverine , Mandea Mioara , Dehant Véronique , Moreira Lorena , Barnoud Anne
Published: February 2023

A cycle of about 6 years has long been observed in the Earth’s magnetic field, length of day, dynamic oblateness, polar motions and surface displacements and attributed to dynamical processes occurring in the core and at the core mantle boundary. Recently, a 6-year cycle has also been detected in the rate of change of the global mean sea level and the ice-mass contributions from Greenland and continental glaciers. In this study, we report new observations of a 6-year cycle in the terrestrial water storage estimates based on the satellite gravity missions GRACE and GRACE-FO, consistent with precipitation and global hydrological models. The causes for such oscillations in the climate system are still unexplained, but raise the question of the respective contributions of the Earth’s deep interior and external surface fluid envelopes to the 6-year cycles reported in many geodetic variables. Indeed, while some of these 6-year fluctuations are convincingly attributed to Earth’s deep interior processes, for some other variables, climate-related processes occurring in the surface fluid envelopes or at the Earth’s surface may be more likely. This issue is exacerbated by an opposition of phase discovered between the angular momentum of the atmosphere and the length of day at around 6 years, suggesting that dynamical processes occurring in the Earth’s core induce a rotation of the solid Earth and the atmosphere as a single system. An overview of the 6-yr cycle observed in different variables of the Earth System may therefore help to better understand potential links between the solid Earth and climate.
Probabilistic predictions of global fire activity
Authors: Torres-Vázquez Miguel Ángel , Gincheva-Norcheva Andrina , Halifa-Marín Amar , Montavez Juan Pedro , Turco Marco
Published: February 2023

Seasonal forecasts of meteorological drought can help decision-making for weather-driven wildfires (Turco et al., 2018). However, one of the main drawbacks of drought prediction lies in the uncertainty of monitoring precipitation in near-real time. In this contribution we assess the predictability of the Standardized Precipitation Index (SPI) on a global scale, combining 11 datasets (DROP; Turco et al., 2020) as observed initial conditions with empirical and dynamic predictions of precipitation. The empirical predictions are based on the ensemble-based streamflow prediction system (ESP, an ensemble-based reordering of historical data) and the dynamics on the new generation seasonal prediction model developed by ECMWF (System 5; S5). Although both systems show comparable quality, S5 performs better at longer forecast timescales, especially over tropical regions.Subsequently, we investigate whether the S5 seasonal forecasts can predict area burned anomalies on a global scale. To do so, we link the seasonal climate predictions of S5 to an empirical climate-fire model, using standard regression techniques in the framework of generalised linear models. The seasonal climate predictions of S5 have shown high and significant performance (with a mean relative operating characteristic “ROC” area value of 0.87) over a large fraction of the burnable area (~47%).In summary, given that all data are publicy available in near real time, our results provide a basis for the development of a global probabilistic seasonal drought and burned area forecast product.ReferencesTurco, M., Jerez, S., Doblas-Reyes, F. J., AghaKouchak, A., Llasat, M. C., & Provenzale, A. (2018). Skilful forecasting of global fire activity using seasonal climate predictions. Nature Communications, 9(1), 1–9.Turco, M., Jerez, S., Donat, M. G., Toreti, A., Vicente-Serrano, S. M., & Doblas-Reyes, F. J. (2020). A global probabilistic dataset for monitoring meteorological droughts. Bulletin of the American Meteorological Society, 101(10), E1628–E1644.AcknowledgementsWe acknowledge funding through the project ONFIRE, grant PID2021-123193OB-I00,funded by MCIN/AEI/ 10.13039/501100011033.
ROBUST – a radio burst identification algorithm using the e-CALLISTO station at University of Graz
Authors: Höfig Lukas , Temmer Manuela , Koller Florian , Drescher Lukas , Monstein Christian
Published: February 2023

The primary condition to produce eruptive solar flare events and solar energetic particles is the opening of magnetic field lines into interplanetary space. In that respect, real-time radio spectra cover important observational information with substantial lead time for space weather warnings. For Space Weather forecasting an objective detection of radio type III and type II bursts is key. We present an algorithm using multiple e-CALLISTO radio stations to detect a) type III bursts, distinguishing between confined and eruptive flares and b) type II bursts, identifying shocks produced by fast coronal mass ejections. We present statistical results for the detection rates and an outlook of the implementation of the algorithm to the e-CALLISTO station at the University of Graz in Austria as well as to the entire international network.
Structural Visualization of Permo-Mesozoic Sediments in Northern Bavaria, Germany – Drone Photogrammetry as a practical Tool for large Areas
Authors: Lang Juergen , Koehn Daniel
Published: February 2023

A major part of Northern Bavaria in Southeast Germany is covered by sedimentary rocks of the Franconian Platform (mainly sandstones, mudstones and limestones). These Permo-Mesozoic continental to shallow marine sediments overlay the Variscan basement and are partially affected by Syn-Variscan structures (Freudenberger and Schwerd, 1996). Further tectonic overprint including Permo-Mesozoic basin extension, Cretaceous inversion and Cenozoic intraplate deformation (e.g., Wiest et al. unpublished) developed a complex fault system. Regionally sparse drill core data as well as large forestry and agricultural cultivation complicate the structural interpretation of the entire area. Drone photogrammetry 3D models from locally selected limestone quarries provide a perfect insight into the structural evolution of Northern Bavaria. Centimetre to several hundreds of metres scale faults, joints and folds are clearly visible and measurable within the models. These local photogrammetry models are implemented into a large scale (Franconian Platform) interpreted 3D model which helps to understand and visualize the major structural features. The photogrammetry models can be used for regional and structural geology teaching purposes. A finished large scale 3D model will be made publicly available through the Bavarian State Office for the Environment LfU (www.lfu.bayern.de). References:Freudenberger, W., and Schwerd, K., 1996, Erläuterungen zur Geologischen Karte von Bayern 1:500 000, München, Bayerisches Geologisches Landesamt, 329 p.Wiest, J.D., Köhn, D., Stollhofen, H., and Dengler, K., The fault network of the Franconian Platform (SE Germany) – workflow, uncertainty, scaling, implications, unpublished.
On the present and future changes in heat waves over India in coupled climate models
Authors: Norgate Marc , Tiwari Pushp Raj , Das Sushant , Kumar Dhirendra
Published: February 2023

It is evident that climate is changing however, there have been not many regional scale systematic efforts to quantify the climate extremes (e.g., heatwave) under various emission scenarios. South Asia has a population of over 1.4 billion, with most of this population located in India and is vulnerable to future changes in high temperature conditions e.g., heat waves and its duration. Here, we use 13 state-of-the-art coupled climate models from CMIP6 experiments along with their ensembles to estimate their fidelity and associated uncertainties in predicting heat waves over the Indian temperature homogenous regions that have resulted from human-induced warming, during the period 1984–2014. We applied various skill metrices for model performance evaluation and found that ensemble of all the 13 CMIP6 models is close to the observation whereas individual model performance varied geographically. This is because individual models have their own interannual variability which affects the overall performance. Further we computed the temperature changes for near future (2030-2060) and far future (2070-2100) at 95% significance level using SSP1, 2 and 5. The maximum temperature during the northern hemisphere summer is projected to increase by 1.3°C, 2.1°C and 3.7°C for SSP1, SSP2 and SSP5 respectively. The frequency of heat waves is also projected to increase, with the most affected areas showing 3+ more heat waves per summer season when compared to historical values. The Indo-Gangetic plain is found in the most affected regions, where weeklong heat wave duration is expected at higher emission scenario affecting larger portion of. population (~ 40% of India’s population). Our findings support the urgent need for more ambitious mitigation and adaptation strategies to minimize the public health impacts of climate change.Keywords: Climate change, Extremes, CMIP
Seasonal variation in the barrier layer of the Banda Sea
Authors: Ismail Mochamad Furqon Azis , Karstensen Johannes
Published: February 2023

The Banda Sea is crucial to the circulation of the world's oceans and atmosphere due to its location within the equatorial regions of the Indonesian Maritime Continent. It links the Pacific and Indian Oceans' circulation via the Indonesian Throughflow and contributes to driving atmospheric conditions via heat and moisture fluxes. Strong salinity-stratified barrier layers have the potential to play a significant role in air-sea interaction by separating the base of the mixed layer from the top of the thermocline and reducing the exchange of surface heat and momentum with the ocean's subsurface. In this study, we present the seasonal variability of barrier layer thickness (BLT) and its formation mechanism in the Banda Sea using the eddy-resolving ocean reanalysis Bluelink version 2020 (BRAN2020) for 1993 to 2021 and air-sea flux data. The findings show that the BLT is a persistent feature in the Banda Sea with a strong seasonal cycle. The BLT maxima appear in the southeast monsoon season period from May to July and the minima in the pre-northwest monsoon season from October-November. The spatial distribution of BLT is zonally oriented along the sea surface salinity (SSS) front from the west to the east of the Banda Sea. We suggest that the horizontal advection of low salinity water from the Java Sea and precipitation contributes to the formation of BLT formation and variability in the Banda Sea.
Google Earth Engine Climate Tool (GEEClimT): Enabling rapid, easy access to global climate reanalysis data
Authors: Lea James , Fitt Robert , Brough Stephen , Carr Georgia , Dick Jonathan , Jones Natasha , Saetnan Eli , Webster Richard
Published: February 2023

Investigation of local to global scale environmental change is frequently underpinned by data from climate reanalysis products, yet access to these can be challenging for both new and established researchers. The practicalities of working with reanalysis data often includes handling large data files that can place limit users on the scale of analysis they can undertake; and working with specialist data formats (e.g. NetCDF, GRIB) that can pose significant barriers to entry for those who may be unfamiliar with them. Together, these factors are limiting the uptake and application of climate reanalysis data within both research and teaching of environmental science.Here we present the Google Earth Engine Climate Tool (GEEClimT), providing an intuitive “point and click” graphical user interface (GUI) for easy extraction of data from 17 climate reanalysis data products relating to atmospheric and oceanic variables (including, but not limited to: ERA5; ERA5-Land; NCEP/NCAR; MERRA; and HYCOM). The GUI is built within the Google Earth Engine geospatial cloud computing platform, meaning users only require an internet connection to rapidly obtain both point data and area averages for user defined regions of interest. To ensure a wide range of usability for researchers, students and instructors, both the GUI and its documentation have been co-created with those who may use reanalysis data for research, teaching, and project purposes. The tool has also been designed with flexibility in mind, allowing it to be easily updated as new datasets become available within the Google Earth Engine data catalogue.GEEClimT is shown to allow users with little or no previous experience of working with climate reanalysis data or coding to obtain temporally comprehensive data for their regions and time periods of interest. Case studies demonstrating the application of the tool to different environmental and ecological settings are presented, showcasing its potentially wide applicability to both research and teaching across environmental science.