bluuebunny/crossref_metadata_2025 huggingface dataset:
Not every large glacial episode lowers valley bottoms: inisghts from the cave systems of the Tatra Mts (the Western Carpathians)
Authors: Szczygieł Jacek , Hercman Helena , Hoke Gregory , Gąsiorowski Michał , Błaszczyk Marcin , Sobczyk Artur
Published: March 2021

The Tatra mountains, the northernmost portion of the Central Western Carpathians, host a stunning alpine landscape despite an average elevation that rises 1.4 km above the surrounding lowlands. Regional geomorphology studies on both sides of the range correlate various landforms interpreted to be glacial in origin with all each of the eight major Alpine glacial  events based largely landscape position, and in some cases geochronologic constraints. This regional relative chronology assumes that wet-based mountain glaciers are efficient agents of erosion and each successive glaciation lowered the valleys within the Tatra. While the tendency of subsequent glaciations to obscure evidence of previous events makes it difficult to study the work done by past glacial episodes, the cave networks on the northern side of the Tatra offer a way to evaluate the amount and timing of valley lowering with U-series dating of speleothems. Epiphreatic and paleophreatic caves that developed near the water table and dried out as valley deepening occurred can serve as excellent recorders of the valley incision history.

Speleothems were collected from a number of cave levels present throughout the northern Tatra, of which only a subset were suitable for U-series geochronology. The oldest speleothems collected in active epiphreatic passages on the valley bottom level from each valley are consistently between 284-325 ka (MIS 8-9). This shows that the modern karst drainage system of the Tatra was established prior to the late Middle Pleistocene, and the cave conduits changed to epiphreatic or vadose conditions between 280 and 330 ka. Since the lowest cave level is at or below the modern valley floor, we can conclude that no valley incision occurred after ~330 ka, which includes both the penultimate and last glaciations periods. Clearly, the regional glacial chronologies in the Tatra must be reassessed. The implications of our findings demonstrate that the assumption of successive valley lowering should not be assumed and that even the extensive MIS2 glaciation did not result in valley lowering despite its size.
Noise maps complexity in regards of environmental properties
Authors: Dellong David , Le Courtois Florent , Boutonnier Jean-Michel , Kinda Bazile G.
Published: March 2021

Maps of underwater noise generated by shipping activity became a useful tool to support international regulations on marine environments. They are used to infer the risk of impact on biodiversity. Maps are performed by 1) computing the emitted noise levels from ships, 2) propagating the acoustic signal in the environment and 3) using localized measurements to validate the results. Because of mismatches in environmental data and a limited number of measurements, noise maps remain highly uncertain.

In this work, the uncertainty of the noise maps is investigated through the potential complexity of soundscape. The acoustic signal at each receiving cell is computed from the convolution of the source of the ships by the transmission losses of the environment. Complexity is mapped by computing Shannon's entropy of the transmission losses for each receiver. High entropy areas only reflect high shipping densities and favorable acoustic propagation properties of the local environment. Low entropy areas reflect: low shipping density and/or poor acoustic propagation properties. An area with high shipping densities and poor acoustic propagation properties will still have low entropy values.

Entropy maps allow classifying areas depending on their environmental features. Thus, scenarios of uncertainty are defined. Results highlight the necessity to consider the diversity of the environmental properties in support of the production of noise maps. The methodology could help in optimizing spatial and temporal resolution of map computations, as well as optimizing acoustic monitoring strategies.
Soil quality indicators across different agro-ecological zones of Mt. Kilimanjaro, Tanzania
Authors: Kimaro Jerome , Treydte Anna , Huwe Bernd , Bogner Christina
Published: March 2021

Introduction The agroecosystems at the southern slope of Mt. Kilimanjaro have been an important resource for the provision of ecosystem services, in particular food production. However, their potential is increasingly threatened by a rapid change in agricultural land use and its future sustainability remains uncertain. Various efforts to achieve sustainable management of agroecosystems have not been successful and therefore there is a risk of land degradation and poverty. This problem is attributed to a lack of knowledge about the actual causes and extent of the problem among local farmers, extension officers and researchers, thus limiting decision options on the selection of appropriate adaptation measures. 

Goals Therefore, we conducted a study to determine how changes in traditional farming systems affect soil quality within the agroecosystem at the southern slopes of Mt. Kilimanjaro. 

Material and Methods We measured C, N, P, soil texture, bulk density and the cation exchange capacity (CEC) in 24 plots across major agro-ecological zones (mainly related to elevation) and in two farming systems (maize and agroforestry).

Results We found that sand content increased, clay content and bulk density decreased with increasing elevation. C content was slightly lower in maize compared to agroforestry (-0.88%), but not N and P. C and N contents increased in the upper compared to the lower elevation zones (3.8% and 0.3%, respectively), while P decreased by 19 mg/kg. The content of cations from CEC showed a heterogeneous picture. The largest difference was the decrease of Ca and Mg in the upper elevation zone (-1191 mg/kg and -458 mg/kg, respectively).

Conclusions Soils in the agroecosystems of Mt. Kilimanjaro differ in their properties which implies that crop yield and quality could be higher on some plots than others. Therefore, the vulnerability to food insecurity and efforts required to improve soil quality could vary locally. The use of soil quality indicators would benefit both farmers and extension officers as a decision-making tool to identify suitable locations for crops, achieve precise use of production inputs and manipulate crop calendars.
Climate change effects on sub-daily extreme precipitation over Europe and the role of natural variability
Authors: Poschlod Benjamin , Ludwig Ralf
Published: March 2021

Sub-daily precipitation extremes over Europe induce hazards such as mass movements and floods. These hazards are impacting the society in terms of financial losses, which is of great interest for insurance companies. The occurrence probability of heavy rainfall events is often assessed by calculating rainfall return periods. Though, these estimations are governed by uncertainties due to the natural variability of the climate system.

Here, we quantify the range of sub-daily extreme precipitation due to natural variability within the single model initial-condition large ensemble featuring 50 members of the Canadian regional climate model, version 5 (CRCM5) under the high-emission scenario Representative Concentration Pathway 8.5. Therefore, we calculate 10-year return levels of sub-daily precipitation for hourly to 24-hourly aggregations in a European domain for each of the 50 ensemble members. The analysis is carried out for four time periods covering 1980 to 2099: the reference period (1980 – 2009) and three future periods (2010 – 2039, 2040 – 2069, 2070 – 2099).

 

We find that the rainfall intensities of the 10-year return levels increase by 5 – 9 % on areal average for every future 30-year period. There, short-duration rainfall intensities increase to a greater extent than longer-duration rainfall intensities. Natural variability as uncertainty source is quantified as the range between the median of the 50 members and the 5th and 95th quantile, respectively. This spread is between -16 % – 20 % for hourly duration and -13 % – 17 % for 24-hourly duration.

 

These findings highlight the large impact of natural variability on the estimation of extreme precipitation return levels. This database also allows us to identify regions in Europe, where future median extreme precipitation exceeds the 95th quantile of the reference period. These regions of significant changes are in northern Europe, central Europe and the eastern part of the Mediterranean.
Future Gravity Mission Concepts for Sustained Observation of Mass Transport in the Earth System
Authors: Pail Roland
Published: March 2021

Next Generation Gravity Missions are expected to enhance our knowledge of mass transport processes in the Earth system, establishing their products applicable to new scientific fields and serving societal needs. Compared to the current situation (GRACE Follow-On), a significant step forward to increase spatial and temporal resolution can only be achieved by new mission concepts, complemented by improved instrumentation and tailored processing strategies.

In extensive numerical closed-loop mission simulations studies, different mission concepts have been studied in detail, with emphasis on orbit design and resulting spatial-temporal ground track pattern, enhances processing and parameterization strategies, and improved post-processing/filtering strategies. Promising candidates for a next-generation gravity mission are double-pair and multi-pair constellations of GRACE/GRACE-FO-type satellites, as they are currently jointly studied by ESA and NASA. An alternative concept is high-precision ranging between high- and low-flying satellites. Since such a constellation observes mainly the radial component of gravity-induced orbit perturbations, the error structure is close to isotropic, which significantly reduces artefacts of along-track ranging formations. This high-low concept was proposed as ESA Earth Explorer 10 mission MOBILE and is currently further studies under the name MARVEL by the French space agency. Additionally, we evaluate the potential of a hybridization of electro-static and cold-atom accelerometers in order to improve the accelerometer performance in the low-frequency range.

In this contribution, based on full-fledged numerical closed-loop simulations with realistic error assumptions regarding their key payload, different mission constellations (in-line single-pair, Bender double-pair, multi-pairs, precise high-low tracking) are assessed and compared. Their overall performance, dealiasing potential, and recovery performance of short-periodic gravity signals are analyzed, in view of their capabilities to retrieve gravity field information with short latencies to be used for societally relevant service applications, such as water management, groundwater monitoring, and forecasting of droughts and floods.
Mapping hedgerow gaps and fostering positive environmental behaviours through a combination of citizen scientists and artificial intelligence
Authors: Parsons Katie , Wolstenholme Josh
Published: March 2021

To meet CO2 reduction targets, the UK aims to plant c1.5 billion trees by 2050. Gaps within thousands of miles of hedgerows across the country are potentially suitable planting sites, but the extent of gaps and suitability for replanting are currently unknown. Maximising the potential growth of hedgerows however appears to receive relatively little attention compared with wide area tree planting. Hedgerow gaps present the opportunity for tree planting, contributing towards the annual tree-planting goals and net-zero CO2 plan as part of Defra’s 25-year objectives (HM Government, 2018), without requiring extensive land change.

Our ambitions of fostering a greener society and meeting net zero goals is heavily reliant on ensuring that children and youth are engaged with environmental concerns and have the right skills and knowledge for future careers. This project has been engaging with youth organisations to enhance their environmental and digital knowledge, whilst combining their input with state-of-the-art artificial-intelligence approaches. The open dataset created with public contributions will inform planting decisions whilst educating young people and citizens. The aligned education programme will provide resources detailing how new planting will drawdown CO2, reduce flood risk and increase biodiversity availability, ultimately fostering the participants as agents of change in addressing the climate crisis. 

Citizens will be trained in hedgerow surveying techniques, with focus on both remote sensing/geographic information systems applications (GIS) and field surveying - enabling contributions from home (during COVID) as well as encouraging outdoor activity and learning. Through a series of surveys and tasks, citizens are able to utilise a smartphone device (or similar) to contribute new data into an open survey on hedgerow characteristics, simple field experimental measurements and images/videos, all whilst utilising the GPS built into the device. The objectives of the project are two-fold: first, data collected by citizens will be used to refine an existing deep learning model trained to identify hedgerow gaps from high-resolution earth observation imagery. Second, to encourage citizens to learn about and take ownership of their local environment, contributing to the fostering of a nation of climate champions.
Location, location, location – Considering local neighborhood when analyzing large samples of UK catchments
Authors: Kiraz Melike , Wagener Thorsten , Coxon Gemma
Published: March 2021

Studying large samples of catchments has been an effective means for comparative hydrology as it provides a wide range of hydrological conditions which can be used to learn similarities and differences between places. Such analyses typically include an attempt to organize catchments along some gradient (e.g. climate) or in clusters (e.g. geology) using catchment descriptors (e.g. an aridity index). Various past studies have pointed to the problem that available catchment descriptors are often not sufficient to capture hydrologically relevant catchment behaviours. It is further widely acknowledged that the water balance of many catchments is not closed. Several hypotheses for the causes of this lack of closed water balance are stated in literature.

If we assume that the dominant control on water balance is climate, then catchments’ water balances should change smoothly in space (since the climate varies smoothly). If they do not, then something else must be controlling this behaviour. We expect that size, location and geology might play important role in the water balances of UK catchments. We aim to study the differences in water balance between catchments to understand the role of catchment location. We test different hypotheses while considering the local neighborhood of 669 UK catchments from the CAMELS-GB dataset.
Crustal contamination and hybridization of an embryonic oceanic crust during the Red Sea rifting: An example from the Tihama Asir igneous complex, Saudi Arabia
Authors: Basch Valentin , Sanfilippo Alessio , Vigliotti Luigi , Langone Antonio , Rasul Najeeb , AlNomani Salem , AlTharowi Ali , Jerais Adel , Ligi Marco
Published: March 2021

The Red Sea rift system represents the best case study of the rift-to-drift history, i.e., the transition from a continental to an oceanic rift and the formation of passive margins. Although the onset of seafloor spreading has been constrained by geophysical observations to 5 Ma in the southern Red Sea, recent studies have suggested that MORB-type melts were intruded within the extended continental crust already during the early stages of rifting. We present here a petro-geochemical investigation of gabbroic bodies and associated basaltic intrusions from the Tihama Asir igneous complex, which formed as part of the intense magmatism that occurred during early Red Sea continental rifting. The most primitive olivine gabbros present modal, bulk and mineral compositions consistent with formation from MORB-type parental melts, but more evolved gabbros and oxide gabbros show saturation of phlogopite and define a geochemical evolution that progressively diverges from that of lower oceanic crust at mid-ocean ridges. Indeed, the Tihama Asir evolved gabbros are characterized by enrichments in LREE and highly incompatible elements (Rb, Ba, U, Th, Nb, Sr, K), suggesting hybridization of a MORB-type parental melt through a process of progressive assimilation of continental crust during the emplacement of gabbroic bodies. Additionally, the gabbros are associated with basaltic dike swarms intruded into the extending continental crust. The basalts show enrichments in LREE and highly incompatible elements similar to the gabbros, suggesting that they formed from melts extracted from the hybridized gabbroic crystal mush. This indicates that the Red Sea oceanization started before the onset of seafloor spreading, and that the cold continental crust was partially assimilated and replaced by hot gabbroic bodies since the early stages of continental rifting.
INtergenerational Stories of Erosion and Coastal community Understanding of REsilience ‘INSECURE’
Authors: Parsons Katie , Halstead Florence , Jones Lisa
Published: March 2021

The Holderness has some of the most rapidly eroding coastline in the world, with sections of cliff retreating >10m per year. These rates are due, in large part, to the soft composition of the boulder clay cliffs, but rates are accelerating rapidly in response to climate drivers, particularly storminess and sea-level rise, which is increasing wave loading.

Withernsea High is a local community school situated close to the eroding cliffs and thus the school students see the day-to-day effects of their changing coastline.  Many of these pupils live within the communities that have ongoing threats of retreating cliffs, with many properties already lost into the sea.

The INSECURE project has used a matrix of participatory research methods to explore how young people engage, examine and understand coastal change within the context of their place within communities. Students were engaged in an education programme to skill them with knowledge and capability to capture their stories and the narratives of their communities. As such this study has been fully youth-led and participants have collected a suite of intergenerational stories from members of the community and the long-term impacts of coastal change. After analysing their data, the young people are using their voice to retell these stories using a variety of creative storytelling methods in order to re-engage their audiences. The outputs are a range of creative short stories, poems and photographs that enable these stories to be told through the eyes of youth.

The outcomes of this project will raise awareness and understanding of coastal change and how communities live with these natural processes that are being exacerbated by climate change and will also measure the impact of the project in addressing climate change knowledge and fostering engagement with the environment and broader social action within the communities.
Southern high latitude vegetation change across the Drake Passage region linked to prolonged intervals of climate cooling during the early Oligocene
Authors: Thompson Nick , Salzmann Ulrich , López Quirós Adrián , Escutia Carlota , Bijl Peter , Hoem Frida , Etourneau Johan , Sicre Marie-Alexandrine , Roignant Sabine , Amoo Michael
Published: March 2021

The possible causes of the onset of Antarctic glaciation around the Eocene-Oligocene Transition (EOT), approximately 34 million years ago (~34Ma), are poorly understood. Uncertainties particularly remain over the role of the Drake Passage opening on the development of the Antarctic Circumpolar Current (ACC), and how this affected both marine and terrestrial environments. A major obstacle in understanding the role of the opening Drake Passage and ACC in Cenozoic climate changes has been the lack of continuous records spanning the EOT from the region. Here we present new palynomorph data from ODP Leg 113 Site 696 Hole B, recording changes in terrestrial environments and paleoclimate across the EOT. The sporomorph assemblage reveals the presence of Nothofagus-dominated forests with secondary Podocarpaceae and an understory of angiosperms and cryptogams growing across much of the Northern Antarctic Peninsula and South Orkney Microcontinent during the late Eocene (~37.60-34.95 Ma). Palaeoclimate reconstructions show that these forests grew under wet temperate conditions, with mean annual temperature and precipitation around 12°C and 1650mm, respectively. Today, similar temperate Nothofagus-dominated mixed-podocarp forests occur in the temperate Valdivian region of southern Chile. At the onset of the EOT, the palynomorph assemblage indicates an unusual expansion of gymnosperms and cryptogams, accompanied by a rapid increase in taxa diversity between ca. 34 and 32 Ma. Sporomorph based climate reconstructions do not provide evidence for an abrupt cooling at the EOT but reveal the onset of prolonged cooling phases throughout the early Oligocene. A contemporaneous increase in reworked Mesozoic sporomorphs at the EOT is likely to be linked to frequent glacial advances from the Antarctic Peninsula and South Orkney Microcontinent, although iceberg-rafted debris from Antarctica cannot be ruled out. We conclude that climate instability and glacial related disturbance at the onset of the EOT facilitated the suppression of Nothofagus and the expansion of a more diverse vegetation with many pioneer taxa that were able to quickly colonise during glacial retreat cycles.
Evaluation of agricultural-related extreme events in hindcast COSMO-CLM simulations over Central Europe 
Authors: Zhang Huan , Tölle Merja
Published: March 2021

Convection-permitting regional climate model simulations may serve as driving data for crop and dynamic vegetation models. It is thus possible to generate physically consistent scenarios for the future-concerning effects of climate change on crop yields and pollinators. Here, we performed convection-permitting hindcast simulations with the regional climate model COSMO5.0-CLM16 (CCLM) from 1980 to 2015 with a spin-up starting at 1979. The model was driven with hourly ERA5 data, which is the latest climate reanalysis product by ECMWF and directly downscaled to 3 km horizontal resolution over central Europe. The land-use classes are described by ECOCLIMAP, and the soil type and depth by HWSD. The evaluation is carried out in terms of temperature, precipitation, and extreme weather indices, comparing CCLM output with the gridded observational dataset HYRAS from the German Weather Service. While CCLM inherits a warm/cold and dry/wet summer/winter bias found in its parent model, it reproduces the main features of the present climate of the study domain, including the distribution, the seasonal mean climate patterns, and probability density distributions. The bias for precipitation ranges between ±20 % and the bias for temperature between ±1 °C compared to the observations over most of the regions. This is in the range of the bias between observational data. Furthermore, the model catches extreme weather events related to droughts, floods, heat/cold waves, and agriculture-specific events. The results highlight the possibility to directly downscale ERA5 data with regional climate models avoiding the multiple nesting approach and high computational costs. This study adds confidence to convection-permitting climate simulations of future changes in agricultural extreme events.
An unsupervised learning approach to identifying blocking events: the case of European summer
Authors: Thomas Carl , Voulgarakis Apostolos , Lim Gerald , Haigh Joanna , Nowack Peer
Published: March 2021

Atmospheric blocking events are mid-latitude weather patterns, which obstruct the usual path of the polar jet stream. Several blocking indices (BIs) have been developed to study blocking patterns and their associated trends, but these show significant seasonal and regional differences. Despite being central features of mid-latitude synoptic-scale weather, there is no well-defined historical dataset of blocking events. Here, we introduce a new blocking index using self-organizing maps (SOMs), an unsupervised machine learning approach, and compare its detection skill to some of the most widely applied BIs. To enable this intercomparison, we first create a new ground truth time series classification of European blocking based on expert judgement. We then demonstrate that our method (SOM-BI) has several key advantages over previous BIs because it exploits all the spatial information provided in the input data and avoids the need for arbitrary thresholds. Using ERA5 reanalysis data (1979-2019), we find that the SOM-BI identifies blocking events with a higher precision and recall than other BIs. We present a case study of the 2003 European heat wave and highlight that well-defined groups of SOM nodes can be an effective tool to reliably and accurately diagnose such weather events. This contrasts with the way SOMs are commonly used, where an individual SOM node can be wrongly assumed to represent a weather pattern. We also evaluate the SOM-BI performance on about 100 years of climate model data from a preindustrial simulation with the new UK Earth System Model (UK-ESM1). For the model data, all blocking detection methods have lower skill than for the ERA5 reanalysis, but SOM-BI performs significantly better than the conventional indices. This shows that our method can be effectively applied to climate models to develop our understanding of how climate change will affect regional blocking characteristics. Overall, our results demonstrate the significant potential for unsupervised learning to complement the study of blocking events in both reanalysis and climate modelling contexts.
Atmosphere-Ocean compound heat wave events in the Eastern Mediterranean
Authors: Behr Lorine , Petalas Stamatis , Jaeger Moritz , Xoplaki Elena , Tragou Elina , Gogou Alexandra , Zervakis Vassilis
Published: March 2021

Mediterranean marine heat waves (MHW) can be defined as abrupt but prolonged, discrete and anomalously warm water events that last for five or more days and exceed temperatures warmer than the 99th percentile (Darmaraki et al. 2019). Like their atmospheric counterpart, Mediterranean MHW have already increased in intensity, frequency and duration - a trend projected to continue under anthropogenic climate change. Recent observations of MHW demonstrated a strong influence of these extreme climatic events on marine organisms, including mass mortalities and shifts in species ranges but also economic impacts on fisheries and aquaculture. MHW can be caused by a combination of atmospheric and oceanic processes and depend on the specific season and location of occurrence. However, the main triggers are generally still not well understood and the current knowledge is largely based on these reported regional impacts. This work focuses on historical (1985 – 2014) atmospheric and marine heat waves in a high resolution CMIP6 model as well as a fully three-dimensional oceanographic hindcast of the interconnected Eastern Mediterranean – Black Sea system. We detect the atmospheric and marine heatwaves and investigate the triggering, compound/concurrent effect of the atmosphere on marine heat waves in the Eastern Mediterranean. For the analysis of atmospheric heat waves, we follow the methodology of Kuglitsch et al. (2010). We use Eastern Mediterranean atmospheric model and ERA-Interim reanalysis to calculate daily maximum (TX) and minimum (TN) air temperatures as well as to set temperature thresholds to estimate the beginning and end of the heat wave events. We identify MHWs from daily sea surface temperatures, applying the approach of Darmaraki et al. (2019). Furthermore, we calculate the heat wave frequency, duration and intensity. The two pairs of datasets are then compared with respect to the spatio-temporal occurrence of heat waves in the atmosphere and ocean, in an effort to reveal feedbacks between the two spheres which would characterize the events as compound. Finally, we estimate a threshold at which an atmospheric heat wave triggers a marine heat wave, and thus a compound event.
Simulations of Föhn in Antarctica with WRF for the Antarctic Mesoscale Prediction System AMPS
Authors: Kirchgaessner Amélie , King John , Gadian Alan , Anderson Phil
Published: March 2021

We examine the representation of Föhn events across the Antarctic Peninsula Mountains during 2011 as they were observed in measurements by an Automatic Weather Station, and in simulations with the Weather Research and Forecasting Model (WRF) as run for the Antarctic Mesoscale Prediction System (AMPS). On the Larsen Ice Shelf (LIS) in the lee of this mountain range Föhn winds are thought to provide the atmospheric conditions for significant warming over the ice shelf thus leading to the initial firn densification and subsequently providing the melt water for hydrofracturing. This process has led to the dramatic collapse of huge parts of the LIS in 1995 and 2002 respectively.

Measurements obtained at a crest AWS on the Avery Plateau (AV), and the analysis of conditions upstream using the Froude number help to put observations at CP into a wider context. We find that, while the model generally simulates meteorological parameters very well, and shows good skills in capturing the occurrence, frequency and duration of Föhn events realistically, it underestimates the temperature increase and the humidity decrease during the Föhn significantly, and may thus underestimate the contribution of Föhn to driving surface melt on the LIS.

Our results indicate that the misrepresentation of cloud properties and particularly the absence of mixed phase clouds in AMPS, affects the quality of weather simulation under normal conditions to some extent, and to a larger extent the model’s capability to simulate the strength of Föhn conditions - and thus their contribution to driving surface melt on the LIS - adequately. Most importantly our data show that Föhn conditions can raise the air temperature to above freezing, and thus trigger melt/sublimation even in winter.
An open source Matlab package for stochastic data analysis in the context of Fokker-Plank Equation and Integral Fluctuation Theorem
Authors: Fuchs André , Kharche Swapnil , Wächter Matthias , Peinke Joachim
Published: March 2021

We present a user-friendly open-source Matlab package for stochastic data analysis. This package enables to perform a standard analysis of given timeseries like scaling analysis of structure functions and energy spectral density, estimation of correlation functions or investigation of the PDF’s of increments including Castaing fits. Also, this package can be used to extract the stochastic equations describing scale-dependent processes, such as the cascade process in turbulent flows, through Fokker-Planck equations and concepts of non-equilibrium stochastic thermodynamics. This stochastic treatment of scale-dependent processes has the potential for a new way to link to fluctuation theorems of non-equilibrium stochastic thermodynamics and extreme events (small scale intermittency, structures of rogue waves). 

The development of this user-friendly package greatly enhances the practicability and availability of this method, which allows a comprehensive statistical description in terms of the complexity of time series. It can also be used by researchers outside of the field of turbulence for the analysis of data with turbulent like complexity, including ocean gravity waves, stock prices and inertial particles in direct numerical simulations. Support is available: github.com/andre-fuchs-uni-oldenburg/OPEN FPE IFT, where questions can be posted and generally receive quick responses from the authors.

This package was developed by the research group Turbulence, Wind energy and Stochastics (TWiSt) at the Carl von Ossietzky University of Oldenburg. We acknowledge funding by Volkswagen Foundation. 
Corona point discharges from grounded rods under high background electric field
Authors: Arcanjo Marcelo , Montanyà Joan , Lorenzo Victor , Pineda Nicolau
Published: March 2021

During the formation of thunderclouds, simultaneous macrophysical and microphysical processes cause the separation of charges inside the cloud, forming the electrical structure of storm clouds. As a result of that, the electric field at the ground level can change significantly. Irregularities on the surfaces of grounded structures can provide conditions for corona discharges that generate ions and form a space charge layer at ground level.

In this work, we investigate the features of corona point discharges from grounded conductive rods installed in three different sites. In all of them, we measured current along the grounded rod under high background electric field conditions or during its fast changes caused by lightning strikes. The current signals reveal pulses with a fast rise time (tens of nanoseconds) and slow decay (hundreds of nanoseconds), with polarity compatible with the background electric field. Comparing laboratory experiments with the results in the field, we observed that positive discharges required a lower electric field threshold than negative discharges. Their pulse frequency is also equivalent to one-tenth of the pulse frequency of negative discharges, for a similar electric field level.

In one of the sites, one current sensor coupled to a grounded rod, 1.5 m above a roof, was installed in a site located at an altitude of 2525 m, near a ski-station. We observed a large number of events, and we were able to correlate the frequency of the pulses with the electric field, as well as evaluate the effect of the wind on the discharges. In the other two sites, the rods were placed near the ground and on the roof of a conventional building. Pulses were registered on some occasions when there was lightning activity nearby, either before or after lightning events. Previous works on this topic correlate the electric field with the average current flow, and on this work, we evaluate the pulse frequency and electric field. This investigation is relevant for understanding the production of corona and space charges from high structures.
Three-dimensional numerical modelling of site effects in the Palatine Hill, Roman Forum, and Coliseum archaeological area
Authors: Razzano Roberto , Moscatelli Massimiliano , Pagliaroli Alessandro , Mancini Marco , Stigliano Francesco , Lanzo Giuseppe
Published: March 2021

In this work we analyzed the three-dimensional seismic site response of the Central Archaeological Area of Rome, which includes the Palatine Hill, Roman Forum, and Coliseum area. The study area is characterized by complex site conditions (stratigraphy, dynamic properties, surficial and buried morphology, etc). Detailed three-dimensional large-scale model was built in order to evaluate site response using dynamic numerical modelling approach. The explicit finite‐difference code FLAC3D (ITASCA Consulting group Inc., 2017) was used for numerical simulations.

The area of Rome is affected by earthquakes from different seismogenic districts: (1) the central Apennine mountain chain, located about 90–130km east of Rome (M = 6.7–7.0); (2) the Colli Albani volcanic area located 20km to the south of the city (M=5.5); and (3) the Rome area itself characterized by rare, shallow, low-magnitude events (M < 5). Both artificial and natural accelerograms were then simulated to be compatible with the reference spectra associated to the three earthquake scenarios.

This study highlights the role of local geological and geotechnical conditions producing amplification of seismic ground motion. The analyses show maximum amplification factors, defined in terms of Housner Intensity ratio for three periods range (0.1-0.5; 0.5-1.0 and 1.0-2.0), as high as 2.2–2.4 over the period range of 0.1–1.0 s. Such values can be significantly relevant for the monumental and archaeological heritage of this area, as many are highly vulnerable due to their great age. Physical phenomena controlling site response are discussed on the basis of buried and surficial morphology and lithostratigraphic conditions.  Finally, microzonation maps are produced in order to ascertain the seismic hazard of the examined area and, consequently, to assess possible parameters for seismic retrofitting of the monuments.
Subduction dynamics, tectonics, and dynamic topography in the Banda-Java subduction zone
Authors: Husson Laurent , Riel Nicolas , Aribowo Sonny , Authemayou Christine , Natawidjaja Danny Hilman , Kaus Boris , de Gelder Gino , Pedoja Kevin
Published: March 2021

At the far end of the Tethyan realm, the Indo-Australian plate subducts in the Java and Banda trenches. Across the trench, a checkerboard-like distribution of continental and oceanic units sets the geodynamic stage since the Australian continent docked into the subduction zone a few Myr ago: to the East, the Australian continent now subducts and collides with the mostly oceanic Wallacea while to the West, the Indian oceanic plate subducts underneath continental Sundaland. We hypothesize that this fast and transient geodynamic regime explains many observations that characterize the region over the last few Myr: slab rollback and formation of the Banda arc, subsidence of the Weber superdeep seafloor to more than 7000 m, back-arc thrusting in Flores, dynamic subsidence in Sundaland and Sahul, and controversial slab tearing underneath Timor. We set out to model subduction dynamics accounting for the complex assemblage of plates in a real-Earth perspective, using the fast thermo-mechanical code LaMEM that allows dealing with complex setups. Our results predict the winding of the subduction zone around Papua, ultimately retreating into the Banda embayment, thereby causing the extreme dynamic subsidence of the Banda seafloor. Geometrical consistency imposes coeval slab tearing underneath Timor while the slab rolls back. The formation of the Flores backthrust quickly follows Australian collision with Wallacea and propagates westward in continental Sundaland. Shortening rates quickly drop tenfold while entering Sundaland, in Java, in agreement with kinematic and structural observations. In the geologically near future, the back-arc thrust is predicted to reverse the subduction polarity, Wallacea being on the brink to subduct southward underneath Australia. Last, transient mantle flow expectedly causes dynamic subsidence in Sahul and Sundaland, thereby profoundly remodeling the physiography of the entire region.
Stability of current Antarctica grounding lines
Authors: Benoît Urruty , Olivier Gagliardini , Fabien Gillet-Chaulet
Published: March 2021

Global warming has a huge impact on the different climatic components. In Antarctica, small changes on the ice-sheet or the ocean may drive the continent to some large instabilities. At a certain threshold, a tipping point might be crossed and the ice-sheet might retreat faster and irreversibly. The TiPACCs (Tipping Points in Antarctic Climate Components) project aims to a better understanding of the tipping points of Antarctica, both in the ocean and in the glaciers.  3 different ice-flow models (Elmer/Ice, PISM, and Ua) are used in the project.  This study is focusing on the Elmer/Ice model to determine and characterize tipping points for its grounding lines. In this presentation, the most famous instability of Antarctica, the Marine Ice-Sheet Instability (MISI), will be investigated. The goal is to define the stability regime of the current Antarctic ice-sheet. For this purpose, multiple initial states have been created.  The Elmer/Ice model uses the inverse method as it has been done in InitMIP-Antarctica (Seroussi et al. 2019) to define initial states. A common initial state for the three TiPACCs models has been defined by the use of common datasets and parameters. The melt at the base of the ice-shelf is defined by the PICO parametrization (Reese, 2016) which permits to define the melting per basins with a box model. Then, perturbations of basalt melt are be applied by modifying the ocean far-field temperature and salinity. The stability of the current grounding line is evaluated by calculating the grounding line migration for the different ice-shelf. The experiments are driven by a small but numerically significant perturbation to observe a retreat of the grounding line. If the grounding line is moving backward when removing the perturbation, then we can conclude that it is stable. Otherwise, if the grounding line is continuing its retreat then it is unstable.

 
Revisiting the Malvinas Current upper circulation and water masses using a HR ocean reanalysis
Authors: Artana Camila , Provost Christine , Poli Léa , Ferrari Ramiro , Lellouche Jean-Michel
Published: March 2021

We use 25 years of ocean reanalysis to revisit the Malvinas Current, a major route of Antarctic Intermediate Waters, from the South (Drake Passage) to the North (Brazil-Malvinas Confluence) from the synoptic to interannual time scales. The MC mean surface velocity structure evolves as the geometry of the continental slope changes. Over the Malvinas Plateau, the slope is gentle, the MC is rather wide and is organized in two jets. As the slope steepens further north, the jets narrow, intensify and merge at 45°S. The MC appears as stable current over the 25 years connecting two of the major regions with high eddy kinetic energy (Drake Passage and the Brazil Malvinas Confluence). The MC plays a minor role in the velocity variations observed at the confluence at seasonal and interannual scales. Velocity variations at the confluence are related with changes in the intensity of the Brazil Current (BC), in particular, the summer intensification (+15 cm/s at the surface) of the BC (34°-36°S over the slope) advects into a winter intensification and southward displacement of the BC overshoot (40/44°S-54°W).  

The Malvinas Plateau is a key region for eddy activity dissipation and for water mass properties modification. Winter deep mixed layers occasionally reach 600 m south of 50°S on the Malvinas Plateau, and show large interannual variations. We compute the volume transport in the layer associated with the Subantarctic Surface Waters (SASW), Subantarctic Mode Waters (SAMW) and Antarctic Intermediate waters (AAIW) over sections spanning the 55 -41°S latitudinal range. The transport time series along the Patagonian slope have a mean of 27.1+- 0.1 Sv and a standard deviation decreasing from south (51°S) to north (45°S) from 4.6 and 3.4 Sv. Variations of SASW/SAMW/AAIW transport are small at the seasonal scale; in contrast, the transport times series vary over a range of 5 Sv at the interannual scale.  In general the transport time series covary and show an absolute minimum in 2004 of the order of 23+-2 Sv. This minimum was associated with a unique southward displacement of the BC overshoot leading to a blocking event at 48°S disconnecting the MC from its source in March, followed by a feeding event in May supplying polar waters reducing the SASW/SAMW/AAIW layer volume. Over the 25 years there is a significant freshening trend and no trend in volume transport. 
Flow duration curves focusing on flood runoff in relation to different distributions of soil and geology in mountainous basins in Japan
Authors: Fujimura Kazumasa , Yanagawa Aki , Iseri Yoshihiko , Murakami Masahiro , Kanae Shinjiro , Okada Shoji
Published: March 2021

The behaviors of flood runoff are related to the soil and geological conditions of basin as well as rainfall, basin scale, and topography. However, the effects of surface conditions on flood runoff in natural basins have not been sufficiently investigated until now. Under the situation of an increasing frequency of disasters due to heavy rainfall, it is important to clarify the contribution of basin conditions to flood runoff to enable flood control planning. The aim of this study is to investigate the relationship between flow duration curves mainly for flood runoff and the areal ratios of different types of soil and geology in the basin. We selected eight mountainous basins with areas from 103 to 331 km2, located in regions of different topographical, geological, and climatological conditions in Japan. The one percentile flow duration curves out of more than 14 years at hourly time steps are used for evaluation. To clarify the properties of flow duration curves, the discharge into the dams, which means the runoff from basins, is shown as runoff height ( Q ), and are normalized, the highest value being, by dividing by the maximum runoff height (Qmax). The flow duration curves are approximated as straight lines on the log-log graph, and the relationships between the slopes and the areal ratios of the different types of soil and geology are shown as scatter plot graphs. The results indicate that the slope of flow duration curves focusing on flood runoff have correlations and significant differences with the areas of (a) Brown Forest soils, and (b) Neogene rock formation, and with the (c) the Andosols/volcanic rock formation ratio.
Re-thinking “Smart City” – transferring urban climate research into city planning processes
Authors: Fallmann Joachim , Schipper Hans , Emeis Stefan , Barra Marc , Tost Holger
Published: March 2021

With more and more people residing in cities globally, urban areas are particularly vulnerable to climate change. It is therefore important, that the principles of climate-resilient city planning are reflected in the planning phase already. A discussion of adaptation measures requires a holistic understanding of the complex urban environment, and necessarily has to involve cross-scale interactions, both spatially and temporally. This work examines the term “Smart City” with regard to its suitability for the definition of sustainable urban planning based on urban climate studies over the past decade and own modelling work. Existing literature is assessed from a meteorological perspective in order to answer the question how results from these studies can be linked to architectural design of future urban areas. It has been long understood that measures such as urban greening, or so-called "Nature Based Solutions", are able to dampen excess heat and help reducing energetic costs. As numerous studies show however, integrating vegetation in the urban landscape shares a double role in regional adaptation to climate change due to both cooling effect and air pollution control. Using the state-of-the-art chemical transport model MECO(n) coupled to the urban canopy parametrisation TERRA_URB, we simulated a case study for the Rhine-Main metropolitan region in Germany, highlighting mutual unwanted relationships in modern city planning. Hence, we oppose the so-called compact city approach to an urban greening scenario with regard to the potential for both heat island mitigation and air quality.