bluuebunny/crossref_metadata_2025 huggingface dataset:
SEA – Science Education and Art – lessons learned from an interdisciplinary conference 
Authors: Lazar Michael , Sher Daniel , Tsadka Maayan , Charit Yaari Naama
Published: March 2022

The seas and oceans cover 70% of the planet and are critical resources for humanity. Responsibly harnessing the seas and oceans while conserving them for future generations requires a deep understanding of the oceans and, potentially, necessitates major changes in how we (as humanity) interact with them. How do we form a bond between people and the sea? What is the role of maritime education and outreach? Do we need to forge an emotional bond (“a love for the sea”), and what are the roles of scientists, artists and educators in forging this bond? How can we engage different communities, creatively overcoming cultural, technological and financial barriers? These are some of the questions that were posed at the 8th Haifa Conference on Mediterranean Sea Research of the Leon H. Charney School of Marine Sciences at the University of Haifa, Israel (July 14-15th, 2021) dedicated to the combination of marine research, science education and art. While art is often used as a means for making research accessible to the public, the aim here was to create a dialog and perhaps a joint outcome between the disciplines. To achieve this goal, five groups of three individuals that included a scientist, educator and artist who deal with similar topics in their daily practice, but from very different perspectives, were formed. These joint topics (time, communication, sound, vision and education) formed the core topical sessions of the conference. The conversations between the individuals were filmed, edited and shown during the conference and each group was invited to present their findings during the first day of the conference. A poster session was set up to allow creative, artistic ideas to be submitted by students who were asked to think about how to present their research outside the box. The conference was broadcast live across the globe on social media simultaneously in English, Hebrew and Arabic (many of the talks are available at https://www.seahaifa2021.com/).  The second day of the conference was devoted entirely to community activities that took place across the country and were open to the general public. These ranged from lectures at the Maritime museum to a workshop on how to make bread from seaweed. The methodology developed for this conference, its results and some thoughts for future activities will be presented here.
The effects of dredged channel geometry on the barrier lake outburst
Authors: Ni Yufang , Huang Wei , Duan Wengang
Published: March 2022

The events of barrier lake outburst have been frequently reported under the impacts of earthquakes, climate change and human activities, which usually brought tremendous disaster to the downstream regions. Dredging a channel is one of the main measures to deal with the barrier lake risk. However, the effects of the channel geometry on the outburst have been unclear. Therefore, we conducted a series of large-scale field experiments on the barrier lake outburst responding to different geometry profiles of dredged channels. Results show that the barrier lake outburst with dredged channel has four development stages, i.e., erosion alongside the dredged channel, backward headcut erosion, rapid development and weak development. For all cases in this work, the peak stage in the reservoir appears earlier than the peak discharge. The rates of the enlargement of the dredged channel are similar among all the cases, while the start time of the enlargement and the final width of the breach are different. Digging of a small notch advances the enlargement of the breach.
Estimating global scale evapotranspiration using soil-based evaporation characteristic length and root zone depth distribution
Authors: Lehmann Peter , Gupta Surya , Or Dani , Carminati Andrea
Published: March 2022

Evapotranspiration (ET) modeling is central to resolving water and energy balances and linking the terrestrial water and carbon cycles. An important challenge remains how to partition the ET flux into transpiration (T) and soil evaporation (E). We expand the surface evaporation capacitor model of Or and Lehmann (2019) by considering concurrent root water uptake. The original capacitor model simulates surface evaporation (focusing on stage-1) and internal redistribution following rainfall events. The thickness of the evaporation-active soil layer is defined by an intrinsic soil property termed the evaporation characteristic length (deduced from soil water characteristics and hydraulic conductivity functions). The modified model considers water extraction by plant roots  from the capacitor layer as well as water redistributed into deeper layers (sheltered from soil evaporation but accessible for root water uptake). Depending on the amount of water leaking below the capacitor depth, vegetation can take up this natural storage at rates limited by the hydraulic properties of the rhizosphere. To model evapotranspiration and its partitioning at the global scale, we use spatial information on (i) maximum root depth and (ii) soil hydraulic properties defining the depth of the capacitor layer. We assess the performance of the ET capacitor model in comparison with results from available land surface models and estimates based on remote sensing products.
Forest fire risk assessment with soil data in Croatia
Authors: Škurić Kuraži Diana , Nižetić Kosović Ivana , Herceg Bulić Ivana
Published: March 2022

Forest fire research can comprise forest fire case studies, laboratory experiments, fire detection by ground sensors, unmanned aerial vehicles and satellites, development of fire behaviour models, fire danger forecast, fire risk assessment, and much more. Commonly used and accepted Canadian method for forest fire danger forecast is expressed as Fire Weather Index (FWI) uses weather data. The index estimates the danger of wildfire and is based on meteorological parameters (air temperature, air humidity, wind speed, and rainfall amount) referring to 12 UTC for that day at the meteorological station or on a numerical weather prediction model grid point.

Knowing how weather and soil interact and affect each other, we propose a new fire risk index based on the innovative Soil Index. Using open-access data, we collected different soil data such as soil temperature and soil moisture, land cover, vegetation, slope, etc. Since there are different types of vegetation and states, Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI) are considered as well. Being focused on forest fires, data about the burned area were also taken into account as well as the slope of the terrain for which the fire risk is calculated.

Since all mentioned data have a diverse horizontal and temporal resolution, we decided to group them by temporal resolution: static, semi-static, and dynamic data. Static data refers to data that rarely change (never or every few years; e.g. land cover). Semi-static data refers to data that vary weekly or monthly (e.g. LAI). Dynamic data group refers to data that is strongly influenced by weather conditions (like soil temperature) and varies every hour. Because of various horizontal resolutions, soil parameters are interpolated to the same horizontal grid. Soil parameters are analysed concerning historical forest fires in Croatia. Despite Soil Index being based on soil parameters, we compared it with Fire Weather Index using data records for historical forest fires in Croatia. Obtained results indicate that the soil index has a better prediction performance compared to FWI. This study also highlights that not only the meteorological environment but also soil conditions are important parameters for fire risk assessment.
Longitudinal patterns of suspended microbial assemblages in glacier-fed streams.
Authors: Jachnická Kristýna , Kohler Tyler J. , Vinšová Petra , Falteisek Lukáš , Singer Gabriel , Vrbický Tomáš , Stibal Marek
Published: March 2022

Glaciers are considered to be a biome with diverse microbial life, and their meltwaters are highly influential to downstream ecosystems by creating a unique riverine habitat template and providing resources such as nutrients and organic matter. Yet, despite unprecedented rates of glacial retreat globally, not much is known about the fate of microbial cells exported from glaciers, despite their potential to colonize and reside in downstream ecosystems. The influence of glacial meltwater on these downstream ecosystems may persist far downstream, but other sources of nutrients, organic matter, and microbial cells within the hydrological catchment likely gain influence with distance from the glacier. These include soils and thawing permafrost - partly via eroding stream banks - and benthic stream biofilms residing both within and outside the glacial environment (e.g. in tributary streams).

In this work, we ask how suspended microbial assemblages change with increasing distance from the source glacier, especially in terms of their composition and corresponding with abiotic environmental factors. We hypothesize that OTU richness will increase with distance from source glaciers as the importance of other catchment sources increase. Specifically, we expect ‘cryospheric’ OTUs to decrease in relative abundance, and more ‘generalist’ freshwater OTUs to increase. We sampled five glacier-fed streams (3 in the Austrian Alps, 1 in Iceland and 1 in Greenland) from the glacier terminus until the ocean or major riverine outlet. DNA was extracted from samples, and 16s rRNA gene amplicons were sequenced to characterize the assemblage structure. These preliminary observations improve our knowledge of the fate of glacially-exported microbial assemblages, and help us to understand the extent of their potential impact for downstream ecosystems, especially in the current age of deglaciation.
Accounting for landslide-channel interactions in landscape evolution and hazards
Authors: Bennett Georgina
Published: March 2022

Landslides are prevalent in mountain landscapes and interact with the river network in a myriad of ways with impacts on flood and debris flow hazards and landscape evolution. Floods in mountainous regions often coincide with a high density of landslides triggered by heavy rainfall. However, the impacts of landslide-delivered sediment on flood dynamics are not typically considered in flood hazard assessment. Higher up in the river network, landslide sediment supply is a key component of debris flows. Yet, assessments of climate change impacts on debris flows to date have focused on likely changes in rainfall triggering potential of debris flows, overlooking the role of landslide sediment supply.

In a first case study, I demonstrate with an example from the Colorado Front Range how landslide-channel feedbacks can significantly amplify channel erosion and flood risk. We used a combination of field analysis and modelling with a multiphase flow model R.avaflow to test the hypotheses that landslide-flood interactions amplified channel erosion during a major flood event in 2013 by (1) bulking of the flow and (2) dam formation and failure dynamics.

In a second case study, I demonstrate with an example from the Swiss Alps, how landslide sediment supply limits debris flow hazard in a warming climate. We forced the sediment cascade model, SedCas, with climate simulations to disentangle the interactions between hydrological triggering, landslide sediment supply and elevation on mountain basin sediment transfer and debris flow hazard over the 21st century. 
Seasonal variability of dust on Mars: Lessons learned from Earth for dust mass estimation
Authors: López-Cayuela María-Ángeles , Zorzano María-Paz , Córdoba-Jabonero Carmen , Carvajal-Pérez Clara Violeta , Guerrero-Rascado Juan Luis
Published: March 2022

The study of dust transport on Mars is crucial to understanding the dust climatic implications. The dust mass loading is one of the main proxies to evaluate indeed the role of dust on the atmospheric dynamics.

Earth studies on dust can serve to estimate the dust mass concentration from the opacity observations on Mars. Nine years of Mars Global Surveyor (MGS) data on Martian weather patterns are available. In particular, the Thermal Emission Spectrometer (TES) database with Martian dust opacity observations is used in this work to assess the seasonal dust mass variability.

First, the space-time variability of the Martian dust opacity is yearly studied using averages in bins of 2° latitude x 5° longitude and 5° aerocentric longitude (Ls). This information allows for estimating the potential planetary dust liftings and depositions. Second, extinction-to-mass conversion factors for dust particles, as obtained from different dust desert regions on Earth (Sahara, Arabian Peninsula, Gobi, …), are applied to Mars dust opacity (i.e., dust extinction) retrievals in order to determine the variability of the dust mass loading during the dust transport on Mars. Third, a seasonal study is performed. Results present an overall dust dynamic scenario in terms of the seasonal dust mass variation across the planet.
Landslide events in Portugal under future climate change scenarios
Authors: Araújo Joana , Ramos Alexandre M. , Soares Pedro M.M. , Melo Raquel , Oliveira Sérgio C. , Trigo Ricardo M.
Published: March 2022

It is expected that landslide events will occur more frequently, throughout the century, as a direct consequence of climate change. The main triggering factor, over Portugal mainland, is extreme precipitation. Thus, the aim of this study relied on the assessment of the projected future changes in the extreme precipitation over Portugal mainland and quantifying the correlation between extreme rainfall events and landslide events through Rainfall Triggering Thresholds (RTT). This methodology was applied for two specific locations within two Portuguese areas of great geomorphological interest.

To evaluate the possible projected changes in the extreme precipitation, we used the Iberia02 dataset and the EURO-CORDEX models’ runs at a 0.11º spatial resolution. First, it was analyzed the models’ performance to simulate extreme values in the precipitation series. The simulated precipitation relied on RCM-GCM models’ runs, from EURO-CORDEX, and a Multimodel ensemble mean. The extreme precipitation assessment relied on the values associated to the highest percentiles, and to the values associated to the RTTs’ percentiles. To evaluate the possible future changes of the precipitation series, both at the most representative percentiles and RTTs’ percentiles, a comparison was made between the simulated values from EURO-CORDEX historical runs (1971-2000) and the simulated values from EURO-CORDEX future runs (2071-2100), considering two emission scenarios: RCP 4.5 and RCP 8.5. In the models’ performance, the Multimodel ensemble mean appeared to be within the best representing models. As for the projected changes in the extreme precipitation for the end of the century, when following the RCP 4.5 scenario, most models projected an increase in the extreme values, whereas, when following the RCP 8.5 scenario, most models projected a decrease in the extreme values.  

 

Acknowledgements

This work was financed by national funds through FCT–Portuguese Foundation for Science and Technology, I.P., under the framework of the project BeSafeSlide (PTDC/GES-AMB/30052/2017)
Intra-annual sediment dynamic assessment in the Wei River Basin, China, using the AIC functional-structural connectivity index
Authors: Wu Zhenni , Baartman Jantiene , Nunes João , López-Vicente Manuel
Published: March 2022

Hydrological and sediment dynamics have changed a lot on the Chinese Loess Plateau during the last six decades due to large scale land use changes and numerous water regulation actions. Understanding the mechanism of sediment transport change and its effects is of great importance to food and environmental security. Computer-implemented numerical approaches are useful to map and assess spatio-temporal patterns in sediment dynamics. This study evaluates monthly and annual sediment connectivity in the Wei River Basin (134,800 km2) at the basin and sub-basin scales using the aggregated index of sediment connectivity (AIC). For the first time, this index is applied on this relatively large regional scale. The two objectives are to (1) evaluate the performance of the AIC at the regional scale and (2) analyse the role played by each input in the sediment patterns over the months of the year. The Jing sub-basin shows the highest sediment connectivity, while the Beiluo sub-basin has the lowest sediment connectivity on average, due to better ecological restoration in Beiluo sub-basin. Within the year, sediment connectivity is highest in April and lowest in January, due to the rainfall regime and land cover variations. Among the inputs of the AIC, the rainfall factor has the highest effect on sediment connectivity, implying that functional connectivity (graded by rainfall and soil cover) dominates over sediment dynamic more effectively than structural connectivity (mainly determined by topography and soil permeability). This study provides one of the first large-scale estimates of spatial and temporal sediment connectivity, which can be further employed to implement regional ecological construction and catchment management.
Pervasive melt migration in hot continental crust – numerical models
Authors: Maierová Petra , Hasalová Pavlína , Schulmann Karel , Štípská Pavla
Published: March 2022

The common view of melt transport in the continental crust involves an initial stage of percolation along grain boundaries, melt segregation into leucosomes and dykes, coalescence of small melt conduits into larger ones and quick nearly vertical melt flow leading to formation of plutons. An entirely different style of melt migration was described in the Bohemian Massif, eastern European Variscan belt. There, a sequence of metaigneous migmatites was described where veins are lacking, leucosomes are rare and relics of melt are spread along grain boundaries. Textural, geochemical and compositional variations in these rocks show that they formed due to equilibration with melt coming from an external source, and that pervasive flow along grain boundaries was the dominant mechanism of melt transport.

The question arises, at what conditions this style of melt transport can operate and what consequences the different styles of melt transport have on the crustal-scale tectonics. We address this question by means of a 2D crustal-scale model of two-phase flow using the code ASPECT (aspect.geodynamics.org). The system of pores through which the melt flows is not resolved in our model and it is described only by its permeability. A low permeability describes material with pores along grain boundaries while a high permeability corresponds to a system of leucosomes, dykes or cracks

For different material properties and thermal conditions we obtain different styles of melt migration and characteristics of the modeled crust. The melt can form a diffuse zone in the lower–middle crust, km-scale waves of high melt fraction gathering into sub-vertical channels, or a horizontal zone with high melt fraction in the middle crust. The lower crust is depleted and the middle crust is enriched in incompatible elements, and composition of the middle crust typically shows km-scale variations. The compositional variations are obtained even in the models with low permeability that corresponds to the melt percolation along grain boundaries, in agreement with the characteristics of the Bohemian migmatites.
First results from the SO/PHI instrument on Solar Orbiter
Authors: Solanki Sami Khan , Blanco Julian , Kahil Fatima , Loeschl Philipp , Strecker Hanna , Hirzberger Johann , Orozco Suárez David , Del Toro Iniesta Jose Carlos , Woch Joachim , Gandorfer Achim , Alvarez-Herrero Alberto , Appourchaux Thierry , Volkmer Reiner
Published: March 2022

The ESA/NASA Solar Orbiter mission, launched in February 2020, has just completed its cruise phase. During its nominal mission, it will explore the Sun and heliosphere from close up and from out of the ecliptic plane. It aims to address the overarching questions of how the Sun creates and controls the heliosphere, and why solar activity changes with time. Among the instruments onboard Solar Orbiter  is the Polarimetric and Helioseismic Imager (SO/PHI), which is the first magnetograph to leave the Sun-Earth line and to observe the Sun from different directions. Already during the cruise phase of Solar Orbiter, SO/PHI has provided a few glimpses of its capabilities, including the excellent quality of the data. In spite of the very limited amount of data gathered during cruise, a few interesting results have already been obtained. A selection of such results will be presented.

 
10 years of characterization of the troposphere in the East Antarctic plateau region using a ground-based Fourier transform spectroradiometer
Authors: Bianchini Giovanni , De Pas Marco , Di Natale Gianluca , Prevedelli Marco , Palchetti Luca
Published: March 2022

Since December 2011 the Radiation Explorer in the Far Infrared (REFIR) Fourier trasform spectroradiometer has been operating continuously from the Italian-French station Concordia, in the Dome C region, Antarctica,  providing a decade long dataset of spectrally resolved atmospheric downwelling radiances in the mid/far-infrared range.

In 2016 The Dome C Tropospheric Observatory (DOCTOR) project was established with the aim to recalibrate and reorganize the full time series of REFIR spectra in order to provide a homogeneous dataset, and to make it available to the scientific community.

A further objective of the DOCTOR project has been to integrate the REFIR spectroradiometer with a Lidar sensor to provide coincident, colocated measurements of tropospheric backscatter profiles.

The downwelling radiance spectra are processed with a retrieval code which is capable to provide vertical profiles of tropospheric temperature and water vapor. The availability of coincident backscatter profiles permits to improve the performance of the retrieval in cloudy sky conditions, providing the vertical structure of clouds which is not easily inferred from the spectra alone.

The resulting observation repository will provide a relevant source of information about tropospheric trends in a region, the East Antarctic plateau, which is sparsely covered by ground-based measurements.
Impacts of recent calving events on upstream flow of Pine Island Glacier and modelling of potential future scenarios
Authors: Sun Sainan , Gudmundsson Hilmar
Published: March 2022

Several calving events have recently occurred on the ice shelf of Pine Island Glacier, which have lead to significant retreat of the ice front by several km. Here we investigate the impact of the 2017 and 2020 calving events on upstream flow and on ice-flux across the grounding line, and quantify the impacts of potential future calving events of similar size. Using the Úa ice-sheet model, we conduct series of inversions for ice rheological parameters and basal sliding conditions prior to observed calving events, and then deactivate areas lost. In general agreement with Joughin et al (2021), we find that the calving events had the potential to cause changes in upstream velocity of similar magnitude as observed. Nevertheless, it appears that at least some of the observed velocity changes may equally be ascribed to modifications over time in the structural rigidity of the ice-shelf margins, which in our numerical simulations is reflected in significant changes over time in inverse estimates of ice-rheology parameters in those areas. For simulations of the near-future response of Pine Island Glacier to similar-sized calving events it can be argued that any distinction between loss of buttressing due to near-front marginal weakening and calving may be immaterial, as both processes appear to happen in tandem, and both lead to similar loss of ice-shelf buttressing. 
Production of Terrestrial Gamma-ray Flashes During the Early Stages of Lightning Flashes
Authors: Lindanger Anders , Skeie Chris A. , Marisaldi Martino , Bjørge-Engeland Ingrid , Østgaard Nikolai , Mezentsev Andrey , Sarria David , Lehtinen Nikolai , Reglero Victor , Chanrion Olivier , Neubert Torsten
Published: March 2022

Terrestrial Gamma-ray Flashes (TGFs) are short emissions of high-energy photons associated with thunderstorms. Since their discovery, it has been clear that they are associated with lightning, and several case studies have shown that the TGFs are produced in the initial phase of the lightning flash. However, it has not been tested whether this is true in general. Here we present such study using the largest TGF sample available to date from the RHESSI, Fermi, AGILE, ASIM catalogs, combined with ground-based radio lightning detection data. Based on stacking analysis of the TGFs and associated lightning activity, together with the high temporal resolution of the optical data from the ASIM photometers, we show that, indeed, TGFs are produced at the beginning of lightning flashes. We also find that the detected sferic activity from the source locations in many cases is enhanced during ~150 - 750 ms following the TGFs, as also reported in Omar et al. (2014) and Smith et al. (2016). This enhanced activity is not present in a randomly-selected sample of flashes, suggesting it is a characteristic property of a significant fraction of flashes that start with a TGF.

The study is submitted to JGR Atmospheres.

Omar et al. (2014), Characterizing the TGF-lightning relationship using ENTLN, AGU Fall Meeting 2014, Abstract AE31A-3388.

Smith et al. (2016), doi:10.1002/2016JD025395.
Linking statistical, hydrodynamic and machine learning models for assessment of compound floods
Authors: Olbert Agnieszka Indiana , Nash Stephen , Comer Joanne , Hartnett Michael
Published: March 2022

Many large population centres are located along estuaries where freshwater flows merge with tidally-driven sea water. In these intertidal zones the river water levels are directly affected by the upstream flow and the downstream coastal conditions. Naturally, such coastal zones can be vulnerable to flood events both from a single driver or several drivers acting in a combination. The compound coastal floods levels may generate extreme impacts even if hazards from individual drivers in isolation would be unlikely. Moreover, the complexity of compound flooding is exacerbated by the presence of interactions (e.g. tide and surge) or dependencies between drivers (e.g. river discharge and surge). To fully understand the multi-driver flood dynamics, the multiple drivers and their impacts need to be assessed in an integrated manner.

In this study the statistical and hydrodynamic models are linked to determine probabilities of multiple-driver flood events and associated risks. Cork City on the south coast of Ireland, frequently subject to complex coastal-fluvial flooding is used as a study case.  The research shows that in Cork Harbour and estuary, the tide-surge interactions have a damping effect on the total water level while dependencies between the surge residual and river flow amplify the risk of flooding. The study also shows that for the most accurate assessment of flood hazard, these phenomena need to be accounted for in the joint probability analysis. From a range of uni- and multivariate scenarios, the multivariate joint exceedance probability AND scenario that includes dependence between multiple drivers represents the most realistic representation of flood probabilities. The outputs from the statistical analysis were used to force the hydrodynamic model of Cork City floodplains. The MNS_Flood model was found to be a robust tool for mapping coastal flood hazards in tidally active river channels. Ultimately, the model results were used to build a machine-learning-based flood forecasting tool. A range of machine learning algorithms were tested to explore relationships between the flood drivers and the resulting spatially variable inundation patterns.

The information derived from the integrated statistical, hydrodynamic and machine learning tools can provide a significant support for short-term early-warning applications as well as for the long-term flood management.
Guidance on optimal vertical covariance localization based on a convection-permitting 1000-member ensemble
Authors: Necker Tobias , Hinger David , Weissmann Martin , Miyoshi Takemasa
Published: March 2022

Appropriate localization is crucial for the success of ensemble data assimilation systems. Localization mitigates sampling errors and damps long-range spurious correlations, which arise from modeling background error covariances using small ensembles. However, finding the best localization function and scale is challenging. Recent studies showed that an optimal localization can depend on various factors such as the atmospheric conditions, the variable of interest, ensemble size, or observation type. Our goal is to improve localization for convective scale data assimilation based on a convection-permitting 1000-member ensemble simulation. The data set covers several forecasts in a high-impact weather period in summer 2016 (Necker et al. 2020a & 2020b). Our latest study aims at finding optimal localization functions and scales in the vertical. We focus on 40-member subsamples and assume the 1000-member ensemble covariance as truth. We estimate optimal localization length scales based on the often-applied Gaspari-Cohn function. Furthermore, we compare the performance of different tapering functions including an exponential-shaped function. The first results indicate that other tapering functions can outperform the Gaspari-Cohn function in the vertical. Optimal localization scales strongly vary between different weather situations. Overall, our analysis assesses covariances and localization between different variables and/or observations covering both model and observation space. This experimental design enables general conclusions independent of a specific data assimilation algorithm.
Quantifying uncertainties in observational datasets over the Carpathian region
Authors: Kalmár Tímea , Kristóf Erzsébet , Hollós Roland , Pieczka Ildikó , Pongrácz Rita
Published: March 2022

Gridded observational datasets are often used for the evaluation of climate simulations. However, uncertainty originating from the selection of observations is as important as the uncertainty of regional climate models. In this study, we introduce a novel evaluation method assessing the uncertainty of observational datasets. For this, various metrics i.e. relative difference and root-mean-square error are also used, and statistical techniques i.e. correlation analysis and permutation test were carried out. We focused on the Carpathian region, which is located in eastern-central Europe. The method is applied to the observational datasets CarpatClim and E-OBS for 2010 – the wettest year in the region since the beginning of the regular measurements. For the comprehensive analysis, not only precipitation and temperature were used, but also geographic variables (elevation, the variability of elevation, and the effect of station density). The evaluation method can be applied to other datasets, different time periods and geographical areas, moreover, it is also appropriate to find errors and shortcomings in the datasets. Based on our findings, CarpatClim is wetter over the whole region (mostly over mountains) than E-OBS. The temperature fields are similar in the two datasets, however, E-OBS is a little warmer than CarpatClim over the mountainous areas. The results show that precipitation depends on station density, while the most important variable for temperature is elevation. The study points out that the choice of reference could have an important effect on the validation of climate simulations and therefore it is essential to take observational uncertainty into account. 
Wind generates seismic noise at Sos Enattos, Sardinia, potential site for the Einstein Telescope.
Authors: Ensing Josiah
Published: March 2022

Seismic noise above 2 Hz band would interfere with the lower frequency output from 3rd generation gravitational wave interferometers.
Sos Enattos, Sardinia, is a potential site for the future Einstein Telescope, which will be built hundreds of meters underground. To characterise one aspect of the seismic field at this potential site, I examined trends in wind speed, direction, and seismic noise. Elevated seismic energy across a broad range of frequencies occurs when wind speeds are higher. At frequencies below 1 Hz, sources appear to be regional (ocean generated microseisms). At 1-50Hz, local sources dominate. Deeper, the effects of local wind-generated noise are reduced and masked by other noise sources.
Identifying the impact of reservoirs on the flow regime across Great Britain 
Authors: Salwey Saskia , Coxon Gemma , Pianosi Francesca , Hutton Christopher , Singer Michael
Published: March 2022

Reservoirs play a vital role in the supply and management of water resources around the world. In Great Britain, reservoir operations are largely determined by the local water company, and there is very little national-scale information available to quantify their impact on river flows. Consequently, large-scale hydrological modelling and data analyses often focus on ‘natural’ or ‘near-natural’ catchments. To support the long-term resilience of water supply and the environment under changing climate and demand, it is essential that we understand where, when and how reservoirs are leading to deviations from a natural flow regime. This will help inform and validate advancements in the large-scale simulation of reservoir-impacted catchments, as well as deepening our understanding of how reservoir operations influence streamflow behaviour.

Due to the age and location of reservoirs across Great Britain, there is a distinct lack of upstream or pre-construction flow timeseries. As a result, we cannot use standard approaches – such as indicators of hydrological alteration- which base analysis on the pre-and-post construction flow regimes. To fill this gap, we define a suite of hydrological signatures and compare observed streamflow timeseries from 1980- 2015 across 166 reservoir catchments and 112 near-natural catchments in Great Britain. We use signatures, characterizing the water balance, flow duration curve and low flow regime, to identify differences in streamflow between these two groups of catchments, and attribute alterations to upstream reservoir operation. We find that gauges with a reservoir upstream are more likely to induce runoff deficits exceeding total PET, and that routine reservoir releases lead to plateaus in the flow duration curve. By defining two new reservoir-based catchment descriptors, our results show that the degree of flow regulation at a gauge depends on the upstream storage capacity and the contributing area of upstream reservoirs. Such descriptors begin to identify thresholds below which the influence of reservoirs is indistinguishable, and help to characterise the extent of reservoir influence across Great Britain.

This analysis highlights groups of reservoir-impacted catchments which cannot be represented by a natural regime. It is in these locations that advancements in large-scale hydrological modelling are crucial for water resource simulation, and that the influence of reservoir operations on the flow regime must be accounted for.
Early warning system for forest fires in Greece: developments and upgrades in the frame of Climpact project
Authors: Kotroni Vassiliki , Giannaros Theodore , Dragozi Eleni , Lagouvardos Kostas , Bezes Antonis , Koletsis Ioannis
Published: March 2022

The METEO unit of the National Observatory of Athens has developed and applies a set of operational services that employ state-of-the-art observational and modeling techniques with the aim to assist both the citizens and the authorities in better preventing, addressing, and ultimately mitigating the adverse impacts of forest fires. The early warning system platform, which has been initially developed in the frame of DISARM project, had been upgraded with improved functionalities in the frame of the CLIMPACT project, a flagship initiative on climate change to coordinate a Pan-Hellenic network of institutions.

The presentation focuses on the description of the system that encompasses the following pillars:

(a) Forecasting of forest fire danger: four widely used indices (Canadian Fire Weather Index - CFWI, Modified Nesterov, Fosberg and Haines) are operationally calculated for the next 3 days at 6kmx6km and 2kmx2km spatial resolution based on 3 state-of-the-art numerical weather prediction models (WRF, Bolam, Moloch). Especially for CFWI the fire danger thresholds have been adapted to the fire environment of Greece;

(b) Real time monitoring of the fire weather conditions: The monitoring is based on the online network of meteorological stations operated by the METEO Unit of NOA that includes ~450 stations across Greece. Fire weather monitoring also includes the daily estimation of landscape flammability using as a proxy the dead fuel moisture content (DFMC). DFMC is calculated using a physically based fuel moisture model and weather station data.

(c) IRIS a rapid response system for fire spread forecasting:  WRF-ARW NWP model and FIRE two-dimensional fire spread model are applied, along with a prototype high-resolution geospatial dataset for the representation of fuels, in a fully-coupled mode in order to account for the two-way interaction between fire and the atmosphere . Major upgrades of the IRIS system achieved in the frame of CLIMPACT include the online calculation of dead fuel moisture, the increase of spatial resolution (40mx40m pixels) of the prototype fuel model for Greece, and the delivery of a forecast guidancewhich includes the categorization (using a 7-level scale) of forest fires based on the forecasted behavioral characteristics.
Rising and settling velocities of macroplastic foils
Authors: Kuizenga Boaz , van Emmerik Tim , Waldschläger Kryss , Kooi Merel
Published: March 2022

Plastics accumulate in the environment due to inadequate waste management, and the durability of the material. A better understanding of fundamental plastic behaviour in the aquatic environment is essential to estimate transport and accumulation, which can be used for monitoring, prevention and reduction strategies. An important process for fate models is the vertical transport of particles, for which the rising and settling velocity are crucial variables. Several studies have described these for microplastics (<0.5 cm) using observations and models. For macroplastics (>0.5 cm) however, such data are scarce. In this study, the rising and settling behaviour of three polymer types (PET, PP, and PE) commonly found in the environment was investigated. The plastic particles were foils of different sizes and shapes. A new method for releasing rising plastics without interfering the flow and disturbing the column was used. Observational data were used to test the performance of four models, including one developed in this study, for estimating the settling and rising velocity based on the properties of the plastic particles. These models were validated using the data obtained in this study, as well as data from another study on plastic rising and settling rates. The newly introduced foil velocity model gave the best results (R² = 0.96 and 0.29 for both data sets, respectively). This model has the potential to estimate the rising and settling velocity of plastic foils, and should be further investigated using additional observational data. The results of our work can be used to further explore the vertical distribution of plastics in rivers, lakes and oceans, which is crucial for improving future efforts to monitor and reduce plastics.
Towards imaging dehydration reactions in the downgoing Nazca plate with local earthquake tomography
Authors: Hassan Nazia , Sippl Christian
Published: March 2022

Intermediate-depth earthquakes in many subduction zones occur in two distinct layers, forming an upper and a lower seismic zone separated vertically by an aseismic or weakly seismic region. These Double Seismic Zones (DSZs) have been related to dehydration reactions in the downgoing crust and mantle lithosphere. Notably, intermediate-depth seismicity in Northern Chile shows a pattern of intraslab seismicity which is quite different from a conventional DSZ. Here, two parallel seismicity planes are present in the updip part of the slab, but at a depth of ∼80–90 km, there is a sharp transition to a highly seismogenic volume of 25–30 km thickness, which corresponds to a closing of the gap between the two seismicity planes.

While such an observation is unique to Northern Chile, understanding the processes behind the formation of this feature should provide important constraints on the mineral processes that govern seismicity in DSZs as well as the role and involvement of fluids. As seismic velocities contain important information about mineralogy and fluid content, we aim at a high-resolution characterization of the seismic wavespeeds of the Northern Chile subduction zone, mainly focusing on the downgoing Nazca slab. We use the seismicity catalog of Sippl et al. (2018) that contains >100,000 earthquakes and 1,200,404 P- and 688,904 S-phase picks for the years 2007 to 2014 to perform local earthquake tomography using the FMTOMO algorithm (Rawlinson et. al., 2006). Data from the seismic stations of the permanent IPOC (Integrated Plate boundary Observatory Chile) deployment in the Northern Chile forearc form the backbone of the dataset, but are complemented by several temporary deployments that span shorter time sequences.

We will present first 3D models of P- and S-wavespeeds from the Northern Chile forearc between about 19°S and 23°S, using a subset of the earthquake catalog mentioned above, as well as images of ray coverage, relocated seismicity and synthetic resolution tests.

The presented seismic velocity distribution will eventually be compared with theoretical wavespeeds that are forward calculated assuming different mineralogical compositions in order to narrow the range of possible reactions that may be occurring at depth.
Relative tropospheric delay fields by GNSS, InSAR and NWP models in an Alpine Region
Authors: Shehaj Endrit , Frey Othmar , Moeller Gregor , Aichinger-Rosenberger Matthias , Geiger Alain , Rothacher Markus
Published: March 2022

Atmospheric interaction with microwaves causes refraction as well as delays of electromagnetic signals. Although the effects are the same for all microwave signals including GNSS and radar, different spatio-temporal sampling of the tropospheric delays, different frequencies resulting in different phase sensitivity to path delays changes, as well as different processing strategies, assumptions and algorithms may lead to differences in the quantified tropospheric estimates. In case of GNSS, the most typical troposphere-related product is the zenith total delay - quantified after the mapping of all GNSS slant delays in the zenith direction. On the other side, double-difference tropospheric slant delays in persistent scatterer interferometry can be obtained in an iterative manner by isolating and subsequently adding the unwrapped low spatial frequency components of the phase residuals to update the estimate of the tropospheric phase. The updated tropospheric phase is then subtracted before the next iteration of point-wise regression-based estimations of topographic corrections and surface displacements. This iterative process is repeated for all scatterers with acceptable standard deviation of the phase residuals until convergence is reached. For comparison of the different tropospheric delays, the spatio-temporal characteristics of GNSS and InSAR observations must be considered. In this work, we use statistical interpolation methods to collocate the GNSS ZTDs with the InSAR measurements. Moreover, as another external (independent) observation we consider 3D fields of numerical weather models, which are integrated in the slant direction to produce (relative) tropospheric delay maps.

As a case study, an alpine region in the Valais area, Switzerland has been selected, which is an interesting scenario due to the high variability of the refractive index over complex terrain. A relatively dense GNSS network, as well as an interferometric time series of Synthetic Aperture Radar (SAR) images are available for the time span of 2008-2013. After introducing the available observations into the collocation approach, we perform the comparison and evaluation of the different tropospheric delays. In addition, we address the following two questions: How should the correct signal part be considered when modeling tropospheric delays using collocation? What is the effect of the GNSS network in terms of size and resolution? This work is an effort in understanding the different estimated/modeled delays, and it aims to set a baseline and a framework for the fusion of GNSS and InSAR tropospheric delays for the monitoring of the atmospheric state over complex terrain.
Tracking ecogeomorphologic states in renaturalized wetlands in Portugal
Authors: Carrasco A. Rita , Sousa Ana I.
Published: March 2022

Wetland restoration has become a fundamental part of the EU strategy for biodiversity and climate action. Far from the long-lasting experience of Central Europe, many of the Southern European countries are still in the early stages of wetland restoration, renaturalization or realignment. Indeed, the passive wetland restoration strategy based on the reconversion of abandoned salt pans to wetlands became popular in Portugal over the last decade. In such period we estimate that only 30 ha of natural/passive and managed renaturalization have been conducted in the two main coastal lagoons of Portugal, Ria Formosa and Ria de Aveiro, with a potential for upscaling close to 400 ha.

In this study, we analyzed the long-term lateral adjustment of renaturalized wetlands based on remote sensing data. During ten years of natural evolution, we identified four main ecogeomorphologic states in these environments: (1) hydrodynamic readjustment and sediment infilling; (2) channelization; (3) mud or sand flats construction/destruction and pioneer vegetation colonization; and (4) vertical accretion and replacement of the tidal flat by the low marsh. The morphological development of the tidal flat (and its colonization by primary producers) was relative fast, occurring in the first 1-2 years after renaturalization, whereas the development of a bimodal interface between tidal flat and low marsh occurred at slower rates (colonization with pioneer vegetation started ~ 3 years after renaturalization). Saltmarsh areas increase at rates ranging between 500 and 1 000 m2/year in the surveyed salt pans. The degree of habitat formation and ecological succession (and services delivery) has been relatively fast, but the full benefits remain to be realized. Currently, there is no effective management strategy for renaturalized wetlands in Portugal, meaning there are no standard indicators to benchmark the success of observed and conducted interventions. The past adopted renaturalization imposed low initial costs, but long-term losses are likely, as most of them might not be a sustainable long-term solution to cope with sea-level rise and carbon accumulation.

There is now a strong environmental and policy momentum to renaturalize new areas and actively restore wetlands in Portugal. With that in mind overcomes the pressing need for interdisciplinary research on restored wetlands adjustment, merging observations and resilience assessment schemes, as well as the development of biogemorphologic indicators of evolution (including ecological successions) after renaturalization/restoration interventions. Also, interdisciplinary research (from natural and social sciences) must be combined with national and regional management plans and policies.