bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the effect of spatial correlation on loss estimation in catastrophe models – a case study for Italy 
Authors: Stripajova Svetlana , Schiappapietra Erika , Pazak Peter , Douglas John , Trendafiloski Goran
Published: March 2022

Catastrophe models are very important tool to provide proper assessment and financial management of earthquake-related emergencies, which still create the largest protection gap across all other perils. Earthquake catastrophe models contain three main components: earthquake hazard, vulnerability and exposure. Simulating spatially-distributed ground-motion fields within either deterministic or probabilistic seismic hazard assessments poses a major challenge when site-related financial protection products are required. Several authors have demonstrated that the spatial correlation of earthquake ground-motion is period-, regionally- and scenario-dependent, so that the implementation of a unique correlation model may represent an oversimplification.

In this framework, we have established a joint research project between the University of Strathclyde and Impact Forecasting, Aon’s catastrophe model development centre of excellence, in order to advance the understanding of spatial correlations within the catastrophe modelling process. We developed correlation models for northern, central and southern Italian regions using both ad hoc and existing ground-motion models calibrated on different databases. Thereafter, we performed both deterministic scenario and event-based probabilistic hazard and risk assessments for Italy using the 2020 European Seismic Hazard and Risk Models. We employed the OpenQuake-engine for our calculations, which is an open-source tool suitable for accounting for the spatial correlation of earthquake ground-motion residuals. The results demonstrate the importance of considering not only the ground-motion spatial correlation, but also its associated uncertainty in risk analyses. Our findings have implications for (re)insurance companies evaluating the risk to high-value civil engineering infrastructures.
Long Term Ecological Monitoring of Large Scale Solar Parks in the UK
Authors: Montag Hannah , Clarkson Tom
Published: March 2022

There is currently a total of 750 large scale solar parks (>5MW) in the UK, with an installed capacity of approximately 7.3GW; this is likely to cover an area of land of around 14,500 ha. While the planning process for such developments is currently geared towards increasing biodiversity gain, there remains a large discrepancy between the way that solar farms are managed and the actual ecological enhancement achieved. With large scale solar parks being a critical part of meeting the targets within the Paris Agreement, it becomes increasingly important to understand how the construction of solar parks impacts local wildlife, where biodiversity net gain can be achieved and the obstacles in the way of maximising this biodiversity net gain.

This talk offers a perspective from a practitioner’s point of view; Clarkson & Woods have carried out ecological monitoring of over 100 operational solar farms since 2016, and have collated an extensive database of botanical data from operational solar arrays. We will present this botanical data based on over 2,000 recorded botanical quadrats and look at how various factors affect botanical diversity including land management approach, age of array and location of quadrat. A discussion of some of the obstacles and potential solutions to maximising biodiversity net gain will be presented based on our knowledge of solar farms in the UK.
Shrinkage-swelling effect on mass transfer through a pore-scale model of the biopore - matrix interface coupling Discrete Element and Finite Volume
Authors: Pires Barbosa Luis Alfredo , Gerke Horst H.
Published: March 2022

Biopore walls are often coated with exudates and finer soil particles such that the soil in the vicinity displays altered hydro-mechanical properties resulting in distinct wettability, permeability and diffusivity when compared to the soil matrix. The mechanical properties in the coating surface (i.e. stiffness and pore structure) may change rapidly during wetting or drying, thus affecting the biopore-matrix mass exchange of water and solutes during preferential flow and local non-equilibrium dynamics.

Since the combined effects of hydro-mechanical properties on the soil structure dynamics are still poorly explored, we developed a cohesive structural model of the biopore - soil matrix interface and varied particle size and stiffness (i.e. Young’s modulus) in Discrete Element Method (DEM). Pore Finite Volume (PFV) was coupled in order to simulate water and air phases during pore scale drainage in 3D. Thus, the model take into account structural responses (i.e. deformations and stresses) during the change from saturated to funicular state. Considering water tension surface constant (0.0728 Pa) and the spherical particles perfectly wettable, four coated surfaces were simulated using a combination of particle radius of 0.1 and 0.2 mm and Young’s modulus of 700 GPa and 1100 GPa. The soil matrix particle properties were constant with radius of 0.3 mm and Young’s modulus of 700 GPa. Lateral drainage was simulated by decreasing the pressure head at the external coated surface, then the air phase invaded soil matrix in direction to the coated area. The retention curve showed higher dependence on particle size rather than particle stiffness. Simulated drainage started relatively slow followed by a rapid saturation decrement. For smaller particles with coated surfaces, the change from slow to rapid drainage was observed twice, for the soil matrix and for coated biopore surfaces. The shrinkage behavior was linear during slow drainage followed by swelling effect in rapid saturation decrement. With the combination of smaller particles and higher Young’s modulus, the plastic deformation and water retention was higher. This coupled effect of heterogeneous mechanical properties on shrinkage-swelling dynamic of biopore-matrix mass exchange bring about a new approach for more complex and realistic models.
A real-time classification method for pipeline monitoring combining Distributed Acoustic Sensing and Distributed Temperature and Strain Sensing
Authors: Huynh Camille , Jestin Camille , Hibert Clément , Malet Jean-Philippe , Lanticq Vincent , Clément Pierre
Published: March 2022

Distributed Fiber Optic Systems (DFOSs) refer to an ensemble of innovative technology that turns an optical fiber into a vast network of hundreds to thousands equally spaced sensors. According to the nature of the sensor, one can be sensitive to acoustic vibration (Distributed Acoustic Sensing, DAS) or to strain and temperature variation (Distributed Temperature and Strain Sensing, DTSS). DAS systems are well suited to detect short-term events in contrast to DTSS systems, which are intended to prevent long-term events. A combination of these two systems appears to be a good way to prevent against most possible events that can appear along an infrastructure. Furthermore, DFOS systems allow the interrogation of long profiles with very dense spatial and temporal sampling. Handling such amounts of data then appears as a challenge when trying to identify a threat along the structure. Machine learning solutions then proves their relevance for robust, fast and efficient acoustical event classification.

The goal of our study is to develop a method to handle, in real time, acquired data from these two DFOSs, classify them according to the nature of their origin and trigger an alarm if required. We mainly focus on major threats that jeopardize the integrity of pipelines. Our database contains leaks, landslides, and third-party intrusion (footsteps, excavations, drillings, etc.) simulated and measured at FEBUS Optics test bench in South-West France. Water and air leaks were simulated using electrovalves of several diameters (1mm, 3mm and 5mm), and landslides with a plate whose inclination was controlled by 4 cylinders. These data were acquired under controlled conditions in a small-scale model of pipeline (around 20m long) along different fiber optic cables installed along the structure.

Our method relies on several tools. A Machine Learning algorithm called Random Forest is used to pre-classify the DAS signal. Our implementation of this algorithm works in flow for a real time event identification. For DTSS signal, a simple threshold is used to detect if a strain or temperature variation occurs. Both results are then gathered and analyzed using a decisional table to return a classification result. According to the potential threat represented by its identified class, the event is considered as dangerous or not. Using this method, we obtain good results with a good classification rate (threat/non-threat) of 93%, compared to 87% if the DAS is used without the DTSS. We have noticed that the combination of both devices enables a better classification, especially for landslides hard to detect with the DAS. This combination enables to dramatically reduce the part of undetected threats from 16% to 4%.
Structural and geothermal changes mapped by drone-based photogrammetry and thermal infrared during the 2021 volcanic crisis of Vulcano Island, Sicily 
Authors: Müller Daniel , Pisciotta Antonino , Walter Thomas R.
Published: March 2022

Vulcano is an active volcanic island located in the south-central sector of the Aeolian Archipelago (Tyrrhenian Sea, Italy). The most recent active edifice is the La Fossa crater located in the center of the island, neighboring the main settlement Vulcano Porto. Its eruptive history is characterized by frequent transitions from phreatomagmatic to minor magmatic activity. The last eruption occurred in 1888–90 with strong phreatic (“Vulcanian”) eruption pulses. During the last decades, it has undergone several periods of volcanic unrest, accompanied by increasing degassing, rising fumarole temperatures, changing gas compositions, or increasing groundwater- and soil temperatures. Major unrest periods were reported in the 1920s, 1940s, and 1990s. Here we report on the ongoing crisis that initiated in September 2021. Rapidly increasing degassing levels and fumarole temperatures, accompanied by seismic activity and surface deformation were detected and monitored by the monitoring network (INGV bulletin reports). The fast evolution and dynamics of the crisis caused authorities to raise the alert level to orange and led to temporary evacuations in Vulcano Porto. We monitored this crisis from the beginning by monthly drone-based optical and thermal infrared overflights. The drone data was processed by using the Structure-from-Motion approach, allowing to generate spatially dense optical and thermal infrared maps. This way we captured the response of the hydrothermal system at the surface in great detail, were able to monitor the spatio-temporal evolution of the high-temperature fumarole field but also associated mean and low-temperature anomalies of diffuse degassing areas. We compared observations to a previous study considering in detail the structure and thermal expression of the La Fossa fumarole field, and the hydrothermal alteration associated (Müller et al., 2021, JVGR). Major aspects of changes observed at the surface during the crisis that could be constrained are (i) an increase of fumarole temperatures, (ii) the development of new fumarole vents, (iii) the evolution of a thermal aureole surrounding the major fumarole field at a distance, and (iv) the formation of a net-shaped thermal anomaly network. Changes are presented on a spatial and temporal scale and highlight the dynamics of degassing systems at the surface with implications for volcanic monitoring and hydrothermal alteration research and suggest that unrest is detectable at fumaroles but also at diffuse degassing zones elsewhere affecting a larger region of the La Fossa cone. 
Submerged beachrock: A tool for reconstructing relative sea level change example from Tekirdag coastline, Sea of Marmara, Turkey
Authors: Tarı Ufuk , Sunal Gürsel , Özcan Orkan , Yaltırak Cenk
Published: March 2022

The beachrock formations represent a significant paleo-environmental proxy because they can record both the vertical and the horizontal evolution of the coastline. They have been used to assess Holocene coastline evolution and crustally induced relative sea level (RSL) change, notably in the Sea of Marmara. In this study, we report existence of the less known submerged beachrocks in the nearshore coastal area of Tekirdag city (Altinova), the northern Sea of Marmara. The beachrocks found in the Tekirdag coastline are locally spread, parallel to the coastline with an extend of about 5 km and at depths ranging from -2 to 0m below present sea level. The beachrock is defined by a calcite-cemented shoreline sandstone. The cement mineralogy and morphology of the beachrocks are indicative of the diagenetic environment, and therefore the examination of the cement characteristics and microstratigraphy can allow identify the type of cement and spatial relationship between the past shoreline and beachrock formation zone.

The Tekirdag coastal area is located in the western Marmara Region. The western coasts of the Marmara Region include a number of natural features inherited from their coastal evolution. Besides, relative sea level change during late Quaternary in this region and its vicinity are generally not homogeneous as a result of the tectonic activity controlled by the North Anatolian Fault Zone (NAFZ) which played a crucial role in the coastline evolution at different periods of the region.

The aim of our study to reconstruct the shoreline modification using beachrocks in the study area. For this purpose, we coupled a series of methodologies for the paleo-environmental and geomorphological study of the coastal zone and the shallow submarine area, which included: a) coring from submerged beachrocks, b) petrographic and microstratigraphic analyses of cementation, c) monitoring of underwater beachrocks and coastal zone by drone and e) dating the formation of beachrocks. Through our analyses we aim to better contribute the use of beachrocks as accurate proxies for the RSL variation in the study area.

 
Correlating deformation events onshore and offshore in superimposed rift basins: the Lossiemouth Fault Zone, Inner Moray Firth Basin, Scotland
Authors: Tamas Alexandra , Holdsworth Robert E. , Underhill John R. , Tamas Dan M. , Dempsey Edward D. , McCarthy Dave , McCaffrey Ken J.W. , Selby David
Published: March 2022

The separation and characterisation of different deformation events in superimposed basins can be challenging due to the effects of overprinting and/or fault reactivation, combined with a lack of detailed geological or geophysical data. This study shows how an onshore study can be enhanced using a targeted interpretation of contiguous structures offshore imaged by seismic reflection data.

Two deformation events, including unambiguous evidence of fault reactivation, are recognised in the onshore part of the Lossiemouth Fault Zone (LFZ), southern-central Inner Moray Firth Basin. The basin is thought to record a history of (possibly) Permian to Cenozoic deformation, but it is commonly difficult to conclusively define the age of faulting and fault reactivation. However, structures in Permo-Triassic strata onshore outcrops show no evidence of growth geometries and new interpretation of seismic reflection profiles offshore reveals that Permo-Triassic fills are widely characterised by subsidence and passive infill of post-Variscan palaeotopography. We propose that sequences of reactivated faulting observed onshore and offshore can be correlated and can be shown in the latter domain to be early Jurassic-late Cretaceous, followed by localised Cenozoic reactivation. The workflow used here can be adapted to characterise deformation events in other superimposed rift basins with contiguous onshore surface-offshore subsurface expressions.
Nickel and Cobalt incorporation in aragonite as a function of mineral growth rate
Authors: Brazier Jean-Michel , Mavromatis Vasileios
Published: March 2022

The chemical and isotopic compositions of carbonates minerals allow to reconstruct the composition of the reactive solutions at the time of their formations and are thus of first importance for paleoenvironmental reconstruction over geological time. In this regard, a huge effort was addressed during the last five decades to study the incorporation, and the associated mechanisms, of traces elements in carbonates minerals. Deciphering the effect of particular physical or chemical parameters on the incorporation of traces in natural CaCO3 is not straightforward and in this respect, experimental studies under highly controlled conditions can provide important insight into our understanding of the chemical signatures of natural samples. In this study, we experimentally investigated the incorporation of Ni and Co in aragonite as a function of mineral growth rate using the constant addition technique at 25°C and 1 bar pCO2. Our results show a linear correlation between the distribution coefficients of Ni and Co and the mineral growth rate suggesting that the latter is likely an important parameter controlling the Ni and Co incorporation in aragonite. In both cases, the distribution coefficients of Ni and Co (i.e., DNi and DCo, respectively) between aragonite and the reactive solution are always lower than unity and increase with increasing growth rate following the trend of incorporation of elements incompatible with the host mineral structure. Based on the dependency of DNi and DCo with the saturation indices (SI) of the reactive solution with respect to aragonite, it was possible to estimate a distribution coefficient at equilibrium for both Ni and Co. These experimental values are several orders of magnitude lower than the theoretically estimated ones in the literature. Furthermore, as for other incompatibles elements the correlation between SI and DNi and DCo point toward the importance of the defect sites in the incorporation of these two elements in aragonite. Finally, our results suggest that DNi and DCoin aragonite could be used to rebuild the saturation state of the reactive solution.
Impact of recent ground thermal changes on the hydrology of a Tibetan catchment and implications for lake level changes
Authors: Martin Léo , Westermann Sebastian , Magni Michele , Brun Fanny , Fiddes Joel , Lei Yanbin , Kraaijenbrink Philip , Mathys Tamara , Immerzeel Walter
Published: March 2022

Ground thermal regime of high mountain catchments impacts the partition between infiltration and runoff, latent and sensible heat fluxes, frozen and liquid subsurface water and the presence (or absence) of permafrost. In the context of global warming, hydrological modifications associated to ground thermal changes are of critical importance for extensive headwater regions such as the Qinghai-Tibet Plateau (QTP) and the Himalayas, which are major water towers of the world. Improving our ability to quantify these changes is therefore a key scientific challenge both regarding basic science and continental-scale water resource management. Many watersheds of the QTP have seen their hydrologic budget modified over the last decades as evidenced by strong lake level variations observed in endorheic basins. Yet, the role of ground thermal changes in these variations has not been assessed.

Lake Paiku (central Himalayas, southern TP) has exhibited important level decreases since the 70s and thus offers the possibility to test the potential role of ground thermal changes and permafrost thaw on these hydrologic changes. We present distributed ground thermo-hydric simulations covering the watershed over the last four decades to discuss their implications on the lake level changes. We use the Cryogrid model to simulate the surface energy balance, snow pack dynamics and the ground thermo-hydric regime while accounting for the phase changes and the soil water budget. Because the surface radiative, sensible and latent heat fluxes in alpine environments are strongly dependent on the physiography, the model is forced with distributed downscaled forcing data produced with the TOPOSCALE model to account for this spatial variability. Simulated surface conditions are evaluated against meteorological data acquired within the basin, ground surface temperature loggers and remotely sensed surface temperatures. The simulations show that, contrary to large scale estimates of permafrost occurrence probability, an significant part of the basin is underlaid by permafrost (>20%). We also show that over the 1980-2020 period, ground temperature warmed up by 1.5 to 2°C per centuries. The permafrost limit rose from 5100 to 5300 m asl (in 40 years). Unfrozen surface conditions increased by around 25 days per century and evaporation increasing by +22% over the period. To represent the impact of these changes on the lake level, we included them in a simple hydrological budget calculation including the contribution of glacier melt and lake evaporation. This approach shows that ground thermo-hydric changes in the catchment have significantly contributed to the lake level changes. These first results highlight the potential of thermo-hydric simulation to better quantify hydrological changes to come in the QTP.
Mesoscale weather systems and their interactions with windfarms: A study for the Kattegat.
Authors: Neirynck Jérôme , Stoffelen Ad , Meyers Johan , van Lipzig Nicole
Published: March 2022

Before an off-shore wind farm is built a thorough resource assessment of all available locations for the farm needs to be performed. Since the power extraction of a wind farm depends on the cube of the wind speed even the mesoscale variability in the wind speed plays an important role in the resource assessment of a wind farm. In order to study mesoscale systems that occur in the vicinity of off-shore wind farms we've set up a convection permitting simulation in COSMO-CLM for the Kattegat sea strait. The Kattegat is particularly interesting since it is an area which features a very irregularly shaped coastline and pronounced coastal effects. Centrally located in the Kattegat lays the 400 MW Anholt wind farm. Operational data of the Anholt wind farm and scatterometer data of the Kattegat are used to validate our simulation. A relatively good agreement between observations and the model output has been found. A variety of mesoscale systems has been identified, both in unstable (e.g. a downburst) as in stable (e.g. gravity waves) conditions. The wind speed variability on temporal scales and on spatial scales over the Kattegat has been investigated. The interactions of the Anholt wind farm with these systems have been investigated using the COSMO-CLM model which incorporates the Fitch wind farm parametrisation. This research is part of a larger project aiming at developing a fast and accurate resource planning and forecasting platform for off-shore wind farms. More information about this project can be found on freewind-project.eu.
Current and future Exposure of Critical Infrastructure to Coastal Flooding in Rostock, Germany
Authors: Fehling Dorothee , Arns Arne , Vafeidis Athanasios
Published: March 2022

We assess the exposure of Critical Infrastructure (CI) to storm surge flooding in the city of Rostock, Germany. The city endured two severe storm surges in 2006 and 2017 that caused the flooding of a main road in the city centre and proved the existing coastal protection measures to be insufficient regarding future sea-level rise (SLR). Using the hydrodynamic model Delft3D-FLOW, we simulate severe storm surge flooding under SLR scenarios of + 30 cm, + 50 cm, + 80 cm and + 100 cm and assess the extent to which CI in the city is affected. Our results show that Rostock’s city harbour (german: Stadthafen) and the adjacent primary road are highly exposed to coastal flooding in all scenarios. Furthermore, transport infrastructure, such as road and railway networks, as well as fire stations are potentially at risk of getting flooded. Besides direct monetary damage, flooding can cause so-called “cascading effects” which are damages that are directly linked to the flooding but occur outside of the directly affected areas. Hence, the cut-off of the primary road can lead to sensitive time loss during emergency situations. The results also indicate that the train connection between Hamburg and large parts of the federal state of Mecklenburg-West Pomerania could fail due to flooding, already in the + 30 cm scenario.
Our study does not account for impacts on the electricity grid as relevant data are not openly available because of data sensitivity. However, electricity data would lead to an improved assessment of the magnitude of the cascading effects more accurately.
We conclude that the critical infrastructure of the city of Rostock is not sufficiently protected against storm surges in the future and emphasise the importance of the plans of the federal state of Mecklenburg-West Pomerania to build new coastal protection measures until the year 2030.
An experimental study on the displacement of large wood in river channels
Authors: Panici Diego , Bennett Georgina
Published: March 2022

Large wood is an essential component of river systems, often considered as the third leg of riverine fluxes (together with water and sediment). Large wood can provide beneficial effects to river restoration and natural flood management (NFM) measures. At the same time, large wood can obstruct bridge openings and increase risk of failure to structures and risk of flooding to adjacent areas. The transport of large wood in rivers crucially affects all the above processes, but to date the importance of factors affecting displacement of large wood in rivers is still poorly understood. Past theories postulated that flow secondary cells may drive large wood trajectories, but have never been confirmed. In this work, we experimentally tested at the flume scale the hydrodynamic factors influencing the displacement of large wood at the river surface. Results showed that past theories were inconclusive, whereas large wood elements tend to follow well-defined trajectories mostly driven by localised changes of the flow velocity. Furthermore, large wood elements are very sensitive to changes in their trajectories at the onset of motion, although are much less prone to change once motion has fully developed. The results from this work will pave the way for better-defined motion models of floating large wood, and will be used to test and calibrate smart sensors for field-based applications.
Last Glacial Maximum Hydro-climate and Cyclone Characteristics in the Levant: A Regional Modelling Perspective
Authors: Ludwig Patrick , Hochman Assaf
Published: March 2022

Proxy-based hydro-climatic reconstructions over the Levant suggest enhanced water availability during the Last Glacial Maximum (LGM) compared to present-day conditions. To date, the governing hypothesis is that additional water availability may be directly linked to increased Cyprus Low frequency and intensity over the region. However, this paradigm has not been tested in a modelling framework. With this aim, we analyzed results from a
weather type classification algorithm and regional climate simulations. The weather type classification is applied to ERA5 Reanalysis data for present-day (1979-2018) and two PMIP3/PMIP4 pre-industrial and LGM model runs. Dynamical downscaling of the two models with the regional WRF model shows that the present hydro-climate can largely be reproduced. Our simulations suggest that both evaporation and precipitation were lower in the LGM compared to pre-industrial conditions, and that their relative changes can thus most likely explain the additional water availability during that time. Indeed, evaporation in the eastern Mediterranean is reduced to a higher degree (~-33%) as compared to precipitation (~-20%) during the LGM. Particularly, lower evaporation during LGM summer may have sustained the year-round wetter conditions in the Levant. In addition, we find significant changes in Cyprus Low characteristics for the LGM. The simulated daily precipitation associated with Cyprus Lows is significantly lower than pre-industrial values (reduction of 26 - 29%), whereas the wind intensity is stronger (increase of 7 - 8%). Finally, a significant increase in Cyprus Low frequency during LGM winter is likely (+22%). Indeed, our findings are in line with a plethora of proxy-based reconstructions, and provide a reinterpretation of the driving mechanism of water availability, i.e., strong changes in evaporation rather than precipitation. This study places projected hydro-climatic drying of the Levant in a long timescale perspective. As such, it improves our understanding of the physical processes influencing the hydrological cycle in this vulnerable region, situated on the border between sub-tropical and mid-latitude climatic zones.
Characterising simulated changes of jet streams since the Last Glacial Maximum
Authors: Schoch Patrizia , Baudouin Jean-Philippe , Weitzel Nils , Kapsch Marie , Kleinen Thomas , Rehfeld Kira
Published: March 2022

Jet streams control hydroclimate variability in the mid-latitudes with important impacts on water availability and human societies. According to future projections, global warming will change jet stream characteristics, including its mean position. Variability of these characteristics on hourly-to-daily timescales is key to understanding the mid-latitudes circulation. Therefore, most analysis methods of present-day jet streams are designed for 6-hourly data. By modelling the climate since the Last Glacial Maximum, we can investigate the long-term drivers of jet stream characteristics. However, for transient simulations of the last deglaciation, 3d wind fields are only archived with a monthly resolution due to storage limitations. Hence, jet variability at shorter timescales cannot be identified, and established methods can’t be used.

Here, we study to what extent changes of jet stream characteristics can be inferred from monthly wind fields. Therefore, we compare latitudinal jet stream positions, strength, tilt and their variability from daily and monthly wind fields in reanalysis data and for LGM and PI simulations. We test three different methods to construct jet stream typologies and metrics. This comparison identifies to which extend these jet stream characteristics can be robustly studied from monthly wind fields. In addition, our analysis assesses the added value of archived daily data for future research. Once the limitations of monthly wind output are known, jet stream characteristics in transient simulations of the last deglaciation can be analysed. This analysis provides new insights on jet stream changes on decadal-to-orbital timescales and identifies the factors controlling these changes.
U-Net Segmentation for the Detection of Convective Cold Pools From Cloud and Rainfall Fields
Authors: Höller Jannik , Härter Jan O. , Fiévet Romain
Published: March 2022

Cold pools are known to mediate the interactions between convective rain cells. Cold pool dynamics thus constitutes an important organizing mechanism for thunderstorms, in particular mesoscale convective systems and extreme rainfall events. Unfortunately, the observational detection of cold pools on a large scale has so far been hampered by the lack of relevant large-scale near-surface data. Unlike in numerical studies, where high-resolution near-surface fields of relevant quantities such as virtual temperature and winds are available and frequently used to detect cold pools, in observational studies cold pools are mainly identified based on surface time series. Since research vessels or weather stations measure these time series locally, the characterization of cold pools from observations is limited to regional or station-based studies. To eventually enable studies on a global scale, we here develop and evaluate a methodology for the detection of cold pools that relies only on data that (i) is globally available and (ii) has high spatio-temporal resolution. We trained convolutional neural networks to segment cold pools in cloud and rainfall fields from high-resolution cloud resolving simulation output. Such data is not only available from simulations, but also from geostationary satellites that fulfill both (i) and (ii). The networks feature a U-Net architecture, a common choice for image segmentation due to its strength in learning spatial correlations at different scales. Based on cloud and rainfall fields only, the trained networks systematically identify cold pool pixels in the simulation output. Our methodology may thus open for reliable global cold pool detection from space-borne sensors. As it also provides information on the spatial extent and the relative positioning of cold pools over time, our method may offer new insight into the role of cold pools in convective organization.
Predicting natural ventilation potential in idealised urban neighbourhoods across Chinese climate zones
Authors: Xie Xiaoxiong , Luo Zhiwen , Grimmond Sue , Sun Ting , Blunn Lewis
Published: March 2022

Natural ventilation is widely used for low-carbon building design. Its potential is influenced largely by the building’s micrometeorological context. Traditionally, weather data used in building energy simulation are observed at rural sites which are far from the site of interest and not representative of the area’s surroundings. Here we combine the Surface Urban Energy and Water Balance Scheme (SUEWS) and the building energy simulation tool, EnergyPlus, to predict the natural ventilation potential (NVP) in buildings located in urban areas in five representative Chinese cities in different climate zones. The meteorological data required by EnergyPlus (e.g. air temperature, relative humidity, wind speed profile) are modelled by SUEWS. The dense urban areas (building fraction λP = 0.6) have an overall warmer and less windy environment compared to rural areas. In summer, the urban-rural natural ventilation hour differences are -3% to -85% (cf. rural) across all climates, while in spring/autumn differences are -25% to 42%. The method is intended to improve the accuracy of NVP prediction using EnergyPlus in cities.
Nanoplastics measurements in Northern and Southern Polar Ice
Authors: Materić Dušan , Kjær Helle Astrid , Vallelonga Paul , Tison Jean-Louis , Röckmann Thomas , Holzinger Rupert
Published: March 2022

It has been established that various anthropogenic contaminants have already reached all the world’s pristine locations, including the polar regions. While some of those contaminants, such as lead and soot, are decreasing in the environment, thanks to international regulations, other novel contaminants emerge. Plastic pollution has been shown as a durable novel pollutant, and, since recently, smaller and smaller plastics particles have been identified in various environments (air, water and soil). Considerable research already exists measuring the plastics in the 5 mm to micrometre size range (microplastics). However, far less is known about the plastics debris that fragmented to the sub-micrometre size (nanoplastics). As these small particles are light, it is expected that they have already reached the most remote places on Earth, e.g. transported across the globe by air movement. In this work, we used a novel method based on Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry (TD-PTR-MS) to detect and measure nanoplastics of different types in the water sampled from a Greenland firn core (T2015-A5) and a sea ice core from Antarctica. We identify polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), and Tire wear nanoparticles in the 14 m deep Greenland firn core and PE, PP and PET in sea ice from Antarctica. Nanoplastics mass concentrations were on average 13.2 ng/mL for Greenland firn samples and 52.3 ng/mL for Antarctic sea ice. We further discuss the possible sources of nanoplastics that we found at these remote locations, which likely involve complex processes of plastic circulation (emission from both land and sea surface, atmospheric and marine circulation).
Sensitivities of simulated atmospheric CH4 concentrations in the ICON-ART Limited Area Mode
Authors: Mamtimin Buhalqem , Roth Franziska , Sunkisala Anusha , Förstner Jochen , Reinert Daniel , Kaiser-Weiss Andrea
Published: March 2022

We conducted CH4 simulations for Europe by using the ICON (ICOsahedral Non-hydrostatic)-ART (Aerosols and Reactive Trace gases) model and emissions from EDGAR.

With respect to the forecast of CH4 in Limited Area Mode (Europe, 6.5 x 6.5 km), the model requires as accurate as possible initial and boundary atmospheric conditions. While the intial data denote here the state of the atmosphere at the start of the model run, the boundary conditions shall denote the data in the lateral boundary zone where the model is forced by the meteorological and CH4 concentration data out side the domain.

The meteorological conditions can be obtained, for example,  from both the DWD's operational numerical weather prediction output or from Copernicus. The Copernicus Atmosphere Monitoring Service (CAMS) provides the necessary boundary CH4 data for the ICON-ART run in Limited Area Mode. The  CH4 initial concentrations can be obtained from Copernicus or from a previous ICON-ART simulation run (e.g., the 24 h CH4 forecast from the previous day).

This way, ICON-ART in Limited Area Mode (LAM) allows for a flexible choice of boundary data and respective sensitivity testing. 

To combine the meteorological data of the ICON with the CH4 concentration data of CAMS as forcing data at the boundary, the CAMS data has to be provided on the same horizontal grid and the same vertical model levels as the ICON data. Since CAMS uses a vertical coordinate of a hybrid sigma-pressure system, the data has, in addition to the horizontal interpolation, to be interpolated vertically to the height based SLEVE coordinate system of ICON.

Also, the EDGAR emission datasets are interpolated to the target ICON grid. Both interpolations are characterized with respect introducing uncertainties.

Thirdly, variation in meteorological conditions is simulated by running ensembles in the ICON-ART LAM.

In this work, the ICON-ART CH4 simulation setup forced by ICON meteorology and CAMS CH4 boundary data is shown to be a useful method to simulate the CH4 atmospheric concentrations at the regional scale and for the purposes of regional atmospheric inversions.

This work has been supported by the project Prototype system for a Copernicus CO2 service (COCO2).

 
Forecasting and mitigating natural hazards with remote and in-situ monitoring 
Authors: Lau Rachael , Segui Carolina , Handwerger Al , Chaney Nate , Veveakis Manolis
Published: March 2022

Fast disasters happen slowly. Two of the most notorious “rapid-onset” disasters – earthquakes and landslides – have a common dependency on a single determining parameter known as the Gruntfest number. Deep-seated landslides, seemingly rapid-onset to the naked eye, have historically been monitored with in-situ monitors and borehole sampling to understand conditions within the shear band. These in-situ monitoring techniques, however, are high-cost and labor-intensive. As satellite data and resources expand, remote sensing has become a more cost-effective and realistic option for monitoring gradual ground deformation caused by the creep of a deep-seated landslide. Differential interferometric synthetic aperture radar (InSAR), specifically, can be used to measure displacements on the Earth’s surface with precision to a few centimeters or less. Here we use InSAR and pre-existing borehole data for the Canillo landslide in Andorra to characterize the evolution of temperature and thereby the Gruntfest number from August 2018-December 2021. Our results reinforce the characteristic models for deep-seated landslides in Segui et. al (2020), suggesting that there exists a critical Gruntfest value where the landslide is catastrophically unstable. Given the anticipated increase in extreme climate with climate change, we expect it to become more frequent for landslides to reach this critical Gruntfest value, therefore necessitating a more robust analysis of the evolution of the Gruntfest number and the overall destabilization process for future work.
Sensitivity of Alpine glaciers to anthropogenic atmospheric forcings
Authors: Clauzel Léo , Gilbert Adrien , Ménégoz Martin , Gagliardini Olivier
Published: March 2022

European Alpine glaciers have strongly shrunk over the last 150 years in response to climate warming. Glacier retreat is expected to persist and even intensify in future projections. This work aims at evaluating how much of the glacier retreat can be attributed to anthropogenic atmospheric forcings. For this purpose, we quantify the evolution of the Argentière glacier in the Mont Blanc area under different climate reconstructions over the period 1850-present. The different reconstructions are extracted from 4 ensemble experiments conducted with the IPSL-CM6-LR General Circulation Model (GCM), excluding and including natural and anthropogenic atmospheric forcings. These 6-member experiments are statistically corrected and downscaled with a quantile mapping approach that ensures consistent long term tendencies and precipitation-temperature relationship. These data feed a three-dimensional ice flow model coupled with a surface mass balance model to simulate changes in the glacier geometry over time. Over 1850-2014, historical simulations show a significant warming whereas there is no clear trend of precipitation at the annual scale. The glacier appears to be highly sensitive to individual anthropogenic forcings, with a glacier volume loss around 45% in the greenhouse gases-only experiment and a growth of about 5% in the aerosols-only experiment in 2014 relative to 1850, compared to the 32% volume loss over the same period in the historical experiment. Moreover, the natural-only experiment reveals the great impact of anthropogenic forcings with a much lower volume loss of about 10%. The latter also confirms that the end of the Little Ice Age would have occurred even without human activities. Finally, the simulations highlight a strong influence of natural internal variability and show that Argentiere Glacier definitively left its possible natural pathway only during the last decade.
Generalizing flood damage mechanism processes of MC Type houses by developing comprehensive flood damage estimation method for Teesta River Basin, Bangladesh 
Authors: Haque Shammi , Ikeuchi Koji , Shrestha Badri Bhakta , Minamide Masashi
Published: March 2022

Flood is one of the most devastating natural disasters. The damages of flood usually vary with the consideration of different factors (depth, duration, velocity, materials of infrastructures) of flooding. Therefore, flood damage estimation is a complex process. Most of previous studies considered only flood depth in developing flood damage functions for residential houses. However, the consideration of other flood parameters such as flood duration and flood velocity are also crucial to estimate flood damage more reliably. Therefore, this study aimed to consider various flood parameters such as flood depth, flood duration, and flood velocity in development of flood damage functions for residential houses.  In this study, the Teesta River Basin in Bangladesh was chosen as the study area. A detailed household questionnaire survey was conducted in flood-affected areas of Lalmonirhat and Rangpur districts (administrative unit of Bangladesh) to collect data of 2017 and 2019 flood events.  Most of the houses in the surveyed flood-affected areas are composed of mud base and side wall of corrugated iron sheets (called “MC type”). For each house, the questionnaire aimed to identify the flood information (flood depth, flood duration, the qualitative representation of flood velocity), household structure information (area, plinth height, ceiling height), structural damage mechanism and the required amount of material with labor work to repair the damage after each flood event. Using the survey data, we have developed depth-damage functions for MC type of house by considering different flood velocity and flood duration combinations. The newly developed depth-damage functions can generalize thresholds of flood depth, flood velocity and flood duration that are responsible for specific type of structural damages (mud removal from the base, mud removal from the base together with side wall instability, full structure instability) of MC type house. Finally, a grid-based approach through the integration of new depth-damage functions with hydrologic-hydraulic model (RRI) and Nays2DFlood Solver (iRIC software) simulation results has been developed to estimate the total flood damage for MC type houses in flood-affected areas of the Teesta River Basin. This comprehensive method can be easily used to derive the depth-damage functions and estimation of total damage for other types of houses if enough surveyed data can be obtained from the field.

Keywords: Flood damage estimation, Depth-damage function, MC type house, Hydrologic-hydraulic model
Local trends of snow water equivalents in the Alps
Authors: Schellander Harald , Winkler Michael , Tilg Anna-Maria
Published: March 2022

The spatial and temporal snow mass variation is clearly indicated as knowledge gap by the “IPCC Special Report on the Ocean and Cryosphere in a Changing Climate”, thus impeding current efforts to quantify historic and future trends. This is especially true for the Alps, which are very rich in snow depth (HS) records (both in number and length), but notoriously lack the same for snow water equivalent (SWE) observations.

The ∆SNOW model - freely available as part of the R-package “nixmass” - improved by temporally varying density parameters (cf. EGU22-2326), is used to estimate SWE at more than 2000 stations with continuous, daily HS records in and around the Alps from flatlands to very high Alpine regions with 130 stations above 2000 m.

In this contribution first results of a trend analysis of historical SWE observations of this very large number of stations is presented. The very high station density and large elevation range covered opens the opportunity for a climatologically detailed and elevation dependent analysis of historic trends of seasonal mean and peak SWE at an unprecedented local scale.
The Origin of Tropospheric Air Masses and related transport processes infer from FTIR measurements and Model Simulations in Western Pacific Region and South America
Authors: Sun Xiaoyu , Palm Mathias , Notholt Justus
Published: March 2022

The Western Pacific Region has some of the highest sea surface temperatures in the world, described as the Tropical Warm Pool (TWP). It plays a major role in the troposphere-stratosphere exchange and, the chemical composition in the TWP will greatly affect that in the Tropical Tropopause Layer (TTL) and therefore the stratosphere. The FTIR station in Koror, Palau (7.5°N, 134°E) is the only FTIR site in the Warm Pool, which was installed as part of the EU-project StratoClim in 2016. The FTIR station in Paramaribo, Suriname (5.8°N, 55°W) was established as part of the EU-program STAR in 2004. The measurement site in Burgos, Philippines (18.5°N, 120.65°E) (Velazco et al., 2017a) just beside the Warm Pool was installed in 2016. Our analysis of FTIR methane measurements at Palau from 11/2018 – 06/2021 and at Suriname from 01/2017 – 05/2021 with the GEOS-Chem model simulations give some insights into transport processes and the origin of air mass in the TWP. The NDACC retrieved CH4 has good sensitivity to the troposphere and stratosphere. Tropospheric and stratospheric XCH4 are analyzed separately based on the FTIR measurements. Simulations of CH4 from the GEOS-Chem model are used to be compared with the measurements from two tropical sites. The position of the Chemical Equator (Hamilton et al., 2008) calculated from the GEOS-Chem model simulations and FLEXPART are used to investigate the seasonal variations of the CH4 measurements from FTIR.