bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring controls on the spatial distribution of bedrock exposure in a mixed bedrock-alluvial river system
Authors: Guirro Mel , Hodge Rebecca , Clubb Fiona , Turnbull-Lloyd Laura
Published: February 2023

In mixed bedrock-alluvial river systems, the riverbed sediment cover depends on interactions between sediment supply, channel morphology and flow characteristics. The controls and dynamics of bedrock exposure are not well understood due to the complexity of interactions between hydraulics and sediment processes. These processes constantly modify the spatial location of bedrock and alluvial reaches over a timescale of hundreds of years. This study aims to understand how channel and sediment properties affect the spatial distribution of bedrock exposure in mixed bedrock and alluvial systems using a combination of numerical modelling and field data. The River Carron in the Scottish Highlands was chosen as the study area as it is a mixed bedrock-alluvial river system with available data on the percentage of sediment cover along the main channel. A numerical model – Network Sediment Transporter from Landlab – was used to simulate sediment transport and track sediment parcels in the River Carron. The river network is represented as a graph made up of nodes and links, in which links are reaches of 100 m. The model was updated to simulate sediment input in every timestep and to calculate the percentage of sediment cover in each reach. A sensitivity analysis of the model was peformed to evaluate how the input parameter values of initial sediment cover, flow depth, grain size, sediment input, and timestep length affect the sediment cover when the simulations achieved a steady state. Field data on topography, bankfull depth and width and grain size were used to estimate initial model input values. We ran the model in spin-up time to freely adjust parameters such as the spatial distribution of bed sediment grain size. The percentage of sediment cover resulting from the model was compared with field data. Scenarios were created by modifying sediment input, flow depth and grain size parameter values in the simulations to determine how these parameters affect the spatial distribution of bedrock exposure of the system. We found that the model did not represent the mixed bedrock-alluvial reaches, as it mostly separated the reaches into either 100% bedrock or 100% alluvial reaches. Numerical modelling is a useful approach to explore controls on the spatial distribution of bedrock exposure, given that data, particularly temporal data, from bedrock rivers are still scarce.
Assessing soil erosion and sediment flux using 137Cs within topographically complex landscapes of Prairie Pothole Region of Canada
Authors: Zarrinabadi Ehsan , Lobb David A.
Published: February 2023

Soil erosion and associated land degradation, accelerated by anthropogenic activities, are serious worldwide environmental problems that can reduce crop productivity and cause on- and off-site damages resulting from sediment transport and deposition. A common feature of the agriculture-dominated landscape of the Prairie Pothole Region in western Canada is depressional wetlands (typically 10 to 20, small seasonal to permanent waterbodies per square kilometer).  These wetlandscapes are fragile agro-ecosystems that have been disturbed and impacted through human-induced soil erosion, receiving influxes of sediment and associated constituents (e.g., phosphorus, organic carbon and pesticides) from the surrounding local and regional sources (e.g., cultivated fields). The general objective of this study was to estimate the severity of soil loss and sedimentation rates, and sediment flux from surrounding cultivated fields into wetlands. The study area included two sub-watersheds in the Prairie Provinces of Manitoba and Alberta, within the Canadian portion of the Prairie Pothole Region. Soil and sediment cores were collected along multiple transects from the uppermost portion of each catchment to the central area of the wetland.  Transects were distributed within catchments to capture the variability resulting from the topographic complexity. The results of this study demonstrated high rates of soil loss in the upper slope and middle slope positions, and high rates of deposition in lower slope and foot slope positions of wetlandscapes. Furthermore, the areal average of transect data provided sediment delivery ratio estimates of 57% for Manitoba and 35% for Alberta, which indicates that a relatively high amount of the mobilized sediment was exported beyond the cultivated fields towards the wetlands, mostly deposited in riparian areas.
Toward Climate Smart and Sustainable cities: Integrated Urban System Methodology and Key Performance Indicators
Authors: Baklanov Alexander ,   WMO IUS and U4SSC Expert Teams
Published: February 2023

Accelerating growth of urban populations has become a driving force of human development, especially in developing countries. Crowded cities are centres of creativity and economic progress; however, extreme weather conditions, flooding, water quality, air pollution and other hazards create substantial vulnerability and challenges in the urban environment.The third United Nations Conference on Housing and Sustainable Urban Development (HABITAT III) in October 2016 adopted the New Urban Agenda (United Nations, 2017), which brings into focus urban resilience, climate and environment sustainability, and disaster risk management. Following the event at the United Nations Economic and Social Council, efforts are required from WMO to consolidate its input to the revision of the New Urban Agenda (NUA) and support urban related activities in a comprehensive manner. Urban development is now a cornerstone of the United Nations 2030 Sustainable Development Goals. It has its own sustainable development goal (SDG 11): Make cities inclusive, safe, resilient and sustainable.To support implementation of urban activities the WMO inter-programme Urban Expert Team under the Commission for Atmospheric Sciences and Commission for Basic Systems (2018) supported by a dedicated team of urban focal points in the Secretariat developed the Guidance on Integrated Urban Hydro-Meteorological, Climate and Environmental Services (IUS). The needs for integrated urban services (IUS) include information for short-term preparedness (e.g. hazard response and early warning systems), longer-term planning (e.g. adaptation and mitigation to climate change) and support for day-to-day operations (e.g. water resources). The aim is to build urban systems and services that meet the special needs of cities through a combination of dense observation networks, high-resolution forecasts, multi-hazard early warning systems, disaster management plans and climate services. This approach gives cities the tools they need to reduce emissions, build thriving and resilient communities and implement the UN Sustainable Development Goals.WMO with its urban cross-cutting approach is involved in joint UN urban activities for development of and implementation of NUA and SDG 11 with a number of external partners, e.g. UN-Habitat, WHO, ITU, GEO, International Association for Urban Climate (IAUC), etc. The IUS methodology is integrated into more broad Multi-Agency UN system U4SSC: United for Smart Sustainable Cities and its key performance indicators (KPIs) for smart sustainable cities.This presentation provides an overview of the current efforts towards future IUSs on urbanization under climate change undertaken by the WMO and UN international initiatives for building climate smart, sustainable and resilient cities.
Multiple criteria-based assessments of Nature-Based Solutions for flood management: a review
Authors: Gallois Lorette , van den Homberg Marc , Cinelli Marco
Published: February 2023

Increased flooding frequency and intensity threaten vulnerable populations’ lives and livelihoods worldwide. Fitting into the preparedness and mitigation phases of the Disaster Risk Management framework used by humanitarian and conservation organisations, Nature-Based Solutions (NBS) have been advanced as effective alternatives to traditional grey infrastructures in order to mitigate flooding impacts. By reproducing natural processes, NBS have shown to provide multiple environmental, social, and economic benefits in addition to their technical performance in mitigating floods. However, a framework to systematically assess these co-benefits is not readily available, which is an obstacle to the effective implementation of NBS on a larger scale. This paper develops such a framework using a Systematic Literature Review (SLR) based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) method. The framework includes a set of descriptors to characterize and analyse NBS consistently. These include:Type of NBS;
Type of protection area (coastal, urban, rural, mountainous, riverine);
Provided environmental/technical/social/economic benefits;
Location of applicability;
Scale of implementation;
Inclusion of stakeholders’ preferences for NBS implementation.
The  SLR is shaped using a combination of scholarly literature (via Web of Science) and grey literature from reputable organizations in the NBS domain and beyond, including the WWF Nature-based Solutions Accelerator, the United Nations Office for Disaster Reduction, the Disaster Risk Management Knowledge Centre, and the Geneva Environment Network. The resulting framework can support decision-making and facilitates the deployment of sustainable infrastructure. The Red Cross Red Crescent Movement and WWF will test the framework in a case study in the Zambezi river basin in Zambia.
Preliminary Results from Comprehensive Seismic and Geodetic Observations Around the Caucasus Region
Authors: Güvercin Sezim Ezgi , Pavlovich Mironov Alexey , Özarpacı Seda , Karabulut Hayrullah , Milyukov Vadim , Ergintav Semih , Zabcı Cengiz , Konca Ali Özgün , Dogan Uğur , Dyagilev Ruslan , Mikhailovich Steblov Grigory , Yıldıran Eda
Published: February 2023

The active deformation and shortening in the Caucasus region are predominantly driven by the collision of Arabian and Eurasian plates where significant differences in the surface uplift, large basins, variations on the plate motion rates along the convergence are observed. To the west of the region the lack of sub-crustal seismic activity, low velocity anomalies in tomographic images and the decreased rate of shortening imply that western Caucasus has different kinematics compared to its east. Previous studies suggested that either slab detachment or lithospheric delamination is responsible for the complex deformation beneath the Caucasus. Large uncertainties due to sparse and non-uniform data coverage for local and regional tomography studies, diffuse seismicity, significant crustal thickness variations and strain field lead to poor understanding on the formation and active deformation of this fold and thrust belt. In this study, we aim to obtain a joint database collected from Turkey and Russia between 2007 and 2020. A waveform data base is created from 37 stations in Russia and more than 60 stations in Turkey. An improved seismicity catalog is built including relocated earthquakes with more than 100 stations. The crustal thickness map of the study region is updated by receiver function analysis using stations both from Turkey and Russia covering the Greater Caucasus. A high resolution Pn tomographic model is computed to determine velocity perturbations in uppermost mantle. The data from GNSS (Global Navigation Satellite System) stations both in Turkey and Russia are processed together for the first time and used to map the updated strain field. The new strain field is correlated with the crustal stress orientations from earthquake source mechanisms. New block models are determined for the Caucasus region in order to better estimate the block boundaries and related slip rates. By the improved azimuthal coverage of the seismic and geodetic stations the uncertainties of vertical and horizontal earthquake locations and the velocity field are reduced, thus; a reliable source for the geometry and kinematics of the faults in the Caucasus region is obtained. With the improved seismological and geodetic observations, reliable inferences on the seismic hazard and earthquake potential is expected for the region.  
Propagation of SH waves in 2-D random media: from ballistic to diffusive behavior
Authors: Celorio Malcon , Chaljub Emmanuel , Margerin Ludovic , Stehly Laurent
Published: February 2023

Random inhomogeneities in the earth can highly influence the characteristics of propagating seismic waves. They exist at all scales and can become an important source of epistemic uncertainty in the ground motion estimation. Despite several works have evaluated these effects, few of them have verified the accuracy of their numerical solutions or controlled the propagation regime they were simulating. In this work we present a comprehensive study of SH wave propagation in 2D random media, which covers from ballistic to diffusive behaviors. In order to understand and identify the interaction of these regimes, we analyzed the coherent and incoherent components of the wavefield. The random media consist in correlated density and velocity fluctuations described by von Kármán autocorrelation function with a Hurst coefficient of 0.25 and a correlation length a=500 m. The Birch correlation coefficient which relates density to velocity fluctuations takes 4 possible values between 0.5 and 1, and the standard deviation of the perturbations is either 5% or 10%. Spectral element simulations of SH wave propagation excited by a plane wave are performed for normalized wavenumbers (ka) up to 5. By measuring the amplitude decay of the coherent wave we obtain the scattering attenuation, which is then compared with theoretical predictions from the mean field theory. Similarly, mean intensities from synthetic waveforms are also compared with those from radiative transfer theory. Both sets of comparisons show excellent agreement between numerical and theoretical predictions. Addionally, we perform statistical analyses on the fluctuations of the ballistic peak which exhibits a transition from log-normal to exponential distribution. These two types of distribution characterize the ballistic and diffusive behaviors, respectively, which means that after certain propagation distances the quasi-ballistic peak is composed mainly by multiply-diffused components. Such critical distance is of the order of the scattering mean free path and offers an alternative method to measure this parameter. Finally, we pay particular attention on the attenuation of the quasi-ballistic peak, which in the forward scattering regime appears to decay exponentially over a length scale known as the transport mean free path.
Luminescence chronology and thermometry studies of plant opal phytoliths
Authors: Spencer Joel , Sanderson David
Published: February 2023

In this work we have been investigating the luminescence properties of plant opal phytoliths to assess their suitability for determination of age and/or thermometric information from soil and sediment sequences. Opal phytoliths, or bio-opal, form when monosilicic acid from soil-waters is taken up by plants and chemically altered to silica, producing intra- or extra- cellular structures that give grasses and stems their strength. Opal phytoliths are usually considered to be non-crystalline and referred to as silica mineraloid structures, with ~4-9% water, <5% other elements, and specific gravity ranging from ~1.5-2.3. They are known to be resistant to degradation and hence preserved in soil or sediment even after decomposition of organic matter. Our earlier work examined a <2.37 g/cm3 density fraction in parallel with quartz grains from samples collected from fluvial terraces and soil pits on Konza Prairie Biological Station native tall grass prairie a few km from Kansas State University. We observed generally similar luminescence characteristics from the phytolith fractions to quartz, with bright blue optically stimulated luminescence (OSL) signals and good single-aliquot regenerative-dose characteristics. In two hours the OSL signal is ~90% bleached by white light, whereas red fluorescence lab lighting has a negligible effect over the same exposure time. Thermoluminescence (TL) data suggested the presence of feldspatic-like minerals or perhaps thermal degradation of the phytoliths during TL measurement; the phytolith fractions were also stimulated by low-temperature infrared stimulated luminescence (IRSL50) perhaps also indicating presence of contaminant minerals. Initial SEM analyses identify what appear to be weathered silica grains, but also highly weathered, pitted concretions with silicate-like structures according to element mapping but actual mineral identification is presently unclear.Most recently we have begun analyzing samples collected from a suite of stratified paleosols from the mid-continent stream type-site of Claussen, Mill Creek, Wabaunsee County, Kansas. This site has documented phytolith examples and a radiocarbon framework. We are continuing luminescence characterization studies, incorporating screening of prepared fractions with SEM and IRSL50 evaluation, and pulsed time domain analysis measurements are being explored.We think luminescence from opal phytoliths shows great promise as an alternative target to quartz or feldspar, but moreover as a sensitive recorder of climatic change or fire exposure on plant communities. This presentation will review our earlier work on phytoliths and discuss most recent findings from the Claussen site.
The Integrated Carbon Observation System (ICOS) - Standardised observations for science and societies
Authors: Kutsch Werner Leo ,   ICOS Research Infrastructure Team
Published: February 2023

To understand, predict and mitigate climate change, it is crucial to have long-term and standardised measurements of greenhouse gas concentrations in the atmosphere and their fluxes between atmosphere, land and oceans. The Integrated Carbon Observation System, is a distributed European Research Infrastructure which provides high-precision and highly standardised observations from more than 170 stations  from three domains: Atmosphere, Ecosystem and Ocean. ICOS covers currently 16 European countries.  All ICOS data is made available by the ICOS Carbon Portal, first in near-real time (within 24h when possible), and after further quality control as domain specific annual releases. The data flow follows the Findable, Accessible, Interoperable, Reusable (FAIR) principles.ICOS data have shown the importance of sustainable long-term observations to understand inter-annual variations, trends and extreme events. They show climate and antropogenic feedback on the carbon cycle and ecosystem-specific responses to disturbances. ICOS data are very useful for good practise guidelines on maintaining or enhancing ecosystem carbon sinks and, thus, might also be an important tool for monitoring and verifying respective policies. Further societal impact is generated by using ICOS data for verification of fossil fuel emission reductions and guiding cities towards climate neutrality.  
Spatio-temporal localization of seismicity in relation to large earthquakes
Authors: Zaliapin Ilya , Ben-Zion Yehuda
Published: February 2023

Progressive localization of deformation may signify a regional preparation process leading to large earthquakes [Ben-Zion & Zaliapin, GJI, 2020; Kato & Ben-Zion, Nat Rev Earth Environ. 2021]. The localization framework describes the evolution from distributed failures in a rock volume to localized system-size events. Ben-Zion & Zaliapin (2020) documented robust cycles of localization and de-localization of background earthquakes with M > 2 in Southern California that precede the M7 earthquakes within 2-4 years. This analysis has been done on regional scale, without posterior selection of the examined areas (e.g., around epicenters of large events). Similar results are observed before M7.8 earthquakes in Alaska using background seismicity with M > 4, and in laboratory acoustic emission experiments.In this work we examine spatial characteristics of the localization process, identifying sub-regions that are responsible for the observed localization and delocalization. The analysis focuses on relative (with respect to other areas) changes in the background intensity. On sub decadal temporal scale, the observed relative seismic activity tends to concentrate on and switch between several subsets of the regional fault network. Within 2-10 years prior to a large event, there is relative activation in a large volume that not necessarily include the impending epicenter. This is followed by a prominent deactivation 2-3 years prior to a large event, reminiscent of the “Mogi donut”, potentially reflecting a transition to aseismic or small events. Some regions may experience multiple activation episodes before a large earthquake. The results emphasize the importance of examining small-magnitude events and joint analyses of seismic and geodetic data.References:Ben-Zion, Y. and I. Zaliapin (2020) Localization and coalescence of seismicity before large earthquakes. Geophysical Journal International, 223(1), 561-583. doi:10.1093/gji/ggaa315
Kato, A. and Y. Ben-Zion (2021) The generation of large earthquakes. Nat Rev Earth Environ 2, 26–39 https://doi.org/10.1038/s43017-020-00108-w
 
Marine Biomass Regeneration: Simple Modelling of Large-Scale Ocean Carbon Dioxide Removal
Authors: Baltas Elisavet , Katavouta Anna , Hunt Hugh
Published: February 2023

Effective and large-scale atmospheric carbon capture is essential in limiting global warming to within 1.5 degrees Celsius as outlined by the Paris Agreement. The oceans make up two thirds of the Earth’s surface and already absorb approximately a quarter of anthropogenic emissions annually, therefore it is imperative to maximise their carbon sequestration ability through large-scale Carbon Dioxide Removal (CDR). One technique that aims to improve the efficiency of oceanic carbon uptake is Marine Biomass Regeneration (MBR), otherwise known as Ocean Iron Fertilisation (OIF). MBR is grounded on evidence that the introduction of certain key nutrients to nutrient depleted areas of the ocean can enhance primary productivity and regenerate ocean biomass, which then acts as a carbon sink. The ocean’s ability to circulate nutrients has been hindered by the over-exploitation of whales, which naturally regulate oceanic nutrient levels by feeding at a depth of 150-200m and defecating at the ocean surface through the whale cycle. Their faeces are rich in nutrients such as nitrates, phosphates and iron, and act as a natural fertiliser. It will take decades to restore the whale population to pre-whaling numbers, therefore, to catalyse the biomass regeneration of oceans, it is proposed that artificial whale faeces are deployed to mimic the whale cycle. A two-dimensional carbon and heat cycling box model with meridional overturning circulation is extended, to include biological processes and nutrient cycling. This model has previously been used to carry out climate projections, by investigating the ocean’s carbon and thermal response to annual anthropogenic emissions, but there has been no investigation on how the changing meridional overturning circulation impacts the biological carbon pump. A simple nutrient-phytoplankton-zooplankton (NPZ) biological model is introduced to model the impact of macronutrient concentrations on phytoplankton and zooplankton growth. Further to this, some basic parameterisations for iron cycling will be added, based off the iron box models of Parekh et al. (2004) and Lefèvre and Watson (1999).  Using the extended model, it will be possible to undertake MBR experiments with different nutrient ratios and concentrations, mimicking the whale cycle, and investigate the impact these parameters have on the oceanic carbon and heat uptake and distribution from anthropogenic carbon emissions. The model also accounts for slower meridional overturning with increased ocean warming, which allows for the investigation of the effect of slower circulation on the biological carbon pump, primary productivity and nutrient distribution.
Comparison of thermal conditions in different intra- and inter-urban structures of different Balkan cities during the summer period
Authors: Dunjic Jelena , Savić Stevan , Milošević Dragan
Published: February 2023

Intensive urbanization and climate change are issues that are affecting majority of the urban areas around the world. Traditional artificial materials that are dominant in most of the cities are enhancing thermal stress that is very pronounced in the summertime especially in urban areas.  Different local and micro locations develop their own specific thermal conditions according to type of the materials that are dominant in the area. Green areas can contribute to improving thermal conditions of the area, but there is few in situ measurements to support those statements.The main aim of the study is to investigate if there are intra- and inter-urban differences or similarities in thermal conditions in cities of different sizes and climate types. Micro-climate conditions (Ta, RH, v and Tg, 1 min. temporal resolution) were assessed using the in situ measurements with Kestrel 5400 Heat Stress Trackers in urban areas during the summer period. The measurement campaigns were conducted in five cities located in three Balkan countries: Serbia (Belgrade and Novi Sad), Bosnia and Herzegovina (Banja Luka and Trebinje), and Slovenia (Ljubljana). The first results indicate that there are significant differences in micro-climatological conditions of different local climate zones within the cities, which confirms that there are intra- and inter-urban differences within the cities and are related to the level of urbanization and presence of natural areas. For example, in Belgrade measurements show that differences in air temperature between densely built-up areas (LCZs 2 and 8) and green areas (LCZs A and B) are up to 7 ºC. Significant differences among the same LCZ are also recorded, depending on the level of shade provided by the urban configuration. Similar results are recorded in other cities where the measurements were performed. The results also show that shade and short- and long-wave radiation plays the most important role when it comes to reducing the outdoor thermal stress. The results are in good accordance with the previous studies that also reported more comfortable conditions in less built-up local climate zones with higher amount of greenery. This kind of assessments contribute to creating more sustainable urban environments that are resilient to climate change and increased thermal stress and extreme events in urban areas.
Microseismicity of the Macquarie Ridge Complex
Authors: Rawlinson Nicholas , Winder Tom , Tkalcic Hrvoje , Stock Joann , Coffin Mike
Published: February 2023

The Macquarie Ridge Complex (situated on the Australian – Pacific plate boundary, in the southwest Pacific Ocean) constitutes a unique geological site, being the only location on Earth where ‘normal’ oceanic crust protrudes above sea level within the ocean basin in which it formed. This raises fundamental questions, including what facilitates the obduction of oceanic crust in this locality (crucial for fully understanding the context around much-studied ophiolite complexes such as the Samail, Oman), and the conditions which led to the largest strike-slip earthquake of the 20th Century (Mw 8.2; May 23 1989).To begin to answer these questions, an array of broadband ocean-bottom and land seismometers was deployed on and around Macquarie Island between October 2020 and February 2022. In this presentation, we summarise the data that were collected – and challenges faced – and show a preliminary catalogue of microseismicity for the duration of the deployment, generated using QuakeMigrate software. QuakeMigrate uses a waveform-based approach to earthquake detection and location, with advantages including improved performance in the presence of heterogeneous noise sources, during intense seismic swarms with small inter-event times, and in automating the processing of large quantities of continuous seismic data. Sophisticated time-domain algorithms allow us to maintain an appropriate detection threshold despite strongly varying noise levels (in the world’s stormiest ocean), varying numbers of operational stations, and in the presence of significant clipping issues on the ocean-bottom instruments’ horizontal channels.We search for temporal variations in earthquake rates, and compute relative relocations (using GrowClust software) to produce high-resolution images of the faults on which the seismicity occurs. These results are interpreted in the context of the location of the most recent large earthquakes on this segment of the plate boundary, and together with complementary geophysical parameters including geodetic measurements and submarine and subaerial fault mapping.
An updated observational record of Davis Strait ocean transports, 2004-2017
Authors: Lenetsky Jed , Lee Craig , Richards Clark , Jahn Alexandra
Published: February 2023

The Davis Strait, located in Southern Baffin Bay between Greenland and the Canadian Arctic Archipelago, is a key gateway of oceanic exchange between the Arctic and North Atlantic Oceans. Large fluxes of fresh Arctic Waters through the Davis Strait potentially influence deep-water formation in the Labrador Sea, with implications for the strength of the Atlantic Meridional Overturning Circulation. From 2004-2017, and 2020-present, ocean temperatures, salinities, and velocities have been measured along a moored array spanning the entire strait, allowing for ocean transports to be assessed over both the continental shelves and central channel. Here we will present new data from 2011-2017, extending the previously published data for 2004-2010. Furthermore, the whole record has been updated, filling spatial and short temporal data gaps using average temperature, salinity, and velocity sections from high resolution Seaglider surveys from 2004 to 2010. These updated volume, freshwater, and watermass transports will increase understanding of changing oceanic conditions in Baffin Bay, as well as local and remote physical mechanisms that govern the Davis Strait throughflow on synoptic to interannual timescales.
EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days
Authors: Widemann Thomas , Straume Anne Grete , Ocampo Adriana , Voirin Thomas , Carter Lynn , Hensley Scott , Bruzzone Lorenzo , Helbert Joern , Vandaele Ann Carine , Marcq Emmanuel , Dumoulin Caroline
Published: February 2023

EnVision was selected as ESA’s 5th M-class mission, targeting a launch in the early 2030s. The mission is a partnership between ESA and NASA, where NASA provides the Synthetic Aperture Radar payload. The scientific objective of EnVision is to provide a holistic view of the planet from its inner core to its upper atmosphere. The mission phase B1 started in December 2021 to complete trade-offs, consolidate requirements, interfaces and system specifications. Phase B1 will be concluded with the Mission Adoption Review planned in fall 2023, followed by Mission Adoption in 2024. To meet its science objectives, the EnVision mission needs to return a significant volume of science data to Earth, with a large distance-to-Earth dynamic range (from 0.3 to 1.7 AU), from a low Venus polar orbit, in the hot Venus environment (exacerbated by the operation of highly dissipative units), while operating three spectrometers in an almost cryogenic level environment. This needs to be achieved within constraints on the spacecraft mass as well as Agency programmatic boundaries. Achieving the science objectives under these multiple constraints without oversizing the spacecraft calls for a careful planning of science operations, making the science planning strategy a critical driver in the design of the whole mission, against which the spacecraft and ground segment are then sized.The payload reference operations scenario simulation demonstrates that all identified surface targets can be imaged with VenSAR, with a performance fully compliant with the science requirements. The first two cycles allow imaging once 80% of the identified Regions of Interest (RoIs) at 30 m resolution. The following two cycles are mostly devoted to 2nd observations of these areas for stereo-topography mapping and the two last cycles to 3rd observations of the “activity” type. Dual polarization and high resolution SAR observations can be performed at any longitude at least once across the 6 cycles. Our strategy is to obtain the widest range of data types that enables us to put the highest resolution datasets into regional and global context. Similarly, understanding atmospheric processes requires a combination of global-scale mapping with targeted observations resolving smaller-scale processes.
Assessing the impact of urban heat islands on the risks and costs of temperature-related mortality
Authors: Huang Wan Ting Katty , Masselot Pierre , Bou-Zeid Elie , Fatichi Simone , Paschalis Athanasios , Sun Ting , Gasparrini Antonio , Manoli Gabriele
Published: February 2023

Ambient temperatures have an impact on human health, with unfavourably warm and cold conditions both associated with elevated mortality risk. By modulating the temperature in urban environments, urban heat islands (UHIs) can therefore both amplify the impact of heat and offer protection against cold weather. In this study, we quantify the impact of UHI on human mortality at 500m resolution for 85 European cities using air temperature simulations and age-dependent epidemiological temperature-mortality relationships for each city. On an annual basis, UHIs have weak net protective effects for most cities examined. This is due to the prevalence of cold to mild days in these cities when an increase in temperature is associated with slight reductions in mortality risk. On a daily basis, however, UHIs induce the greatest impact during heat extreme days, with a median of 39% increase in risk compared to a 7% reduction during cold extreme days. A valuation of such mortality risk reveals that the annual cost of UHI-related heat mortality is comparable to air pollution-related mortality costs as well as transit costs. Cities with Arid climates and Temperate Dry Summer climates in Southern Europe tend to experience the greatest protective UHI effects during cold extreme weather and the least adverse effect during heat extremes, while cities with Cold climates in Eastern and Northern Europe tend to benefit the least during cold extremes. Annually, the net impact of UHI is most strongly correlated with each city’s vulnerability to heat and cold and the ratio of warm vs. cold days in a year.
Coastal Sea State Uncertainty From a Triple Collocation Analysis of Observations During the Sentinel-6 Michael Freilich – Jason-3 Tandem Phase Experiment
Authors: Timmermans Ben , Gommenginger Christine , Banks Chris
Published: February 2023

The growing satellite record of sea state observations is becoming increasingly important for climate change research, to improve ocean and weather forecasts and to inform climate change mitigation and investment strategies. In this context, coastal processes and impacts are of particular concern, driving a yet stronger research imperative. The Copernicus Sentinel-6 Michael Freilich (S6-MF) mission was launched in November 2020 by the European Space Agency to succeed Jason-3 (J3) as the long term satellite altimetry reference mission. S6-MF commissioning involved a unique 12-month Tandem Experiment during which S6-MF flew approximately 30 seconds behind J3 on the same ground tracks, resulting in an unprecedented global dataset of quasi-simultaneous collocated altimeter sea state measurements in Low-Resolution Mode (LRM) and Synthetic Aperture Radar (SAR) mode.In this work, this unique dataset is examined to evaluate uncertainties in altimeter significant wave height (Hs) observations from the two missions in different operating modes and different sea state conditions. A particular focus is placed on the evaluation of uncertainties in the coastal zone by exploiting the large number of moored buoys located near the coast of the U.S. S6-MF and J3 data are compared with buoy measurements and reanalysis data using, amongst other methods, triple collocation (TC) analysis. Attention is paid to both the collocation methodology and possible correlation of random errors. Results indicate that, over both global and coastal oceans, J3 and S6-MF Low-Resolution Hs are almost identical, with near-zero bias, low RMS difference and very high correlation. This very high correlation precludes the use of triple collocation to the J3/S6-MF-SAR/buoy triplets. Comparing S6-MF SAR with J3 LRM and buoys confirms the positive sea-state dependent bias in SAR Hs. Triple collocation of J3, S6-MF and buoys reveals the sensitivity of measurement uncertainty to collocation criteria, particular in coastal areas. Further, we show how sea state dependence of measurement uncertainty varies between oceanic and coastal settings. In general, we find that steeper spatial gradients of sea state typically associated with coastal regions can hamper interpretation of TC analyses without undue consideration. These findings demonstrate the value of the Tandem Experiment to evaluate uncertainty and provide evidence of the stability and/or enhancements of new mission data contributing to the growing satellite climate record.
Tracking the evolution of spheromak flux ropes in ambient interplanetary magnetic field and plasma environments.
Authors: Asvestari Eleanna , Rindlisbacher Tobias , Pomoell Jens , Kilpua Emilia , Sarkar Ranadeep
Published: February 2023

Interplanetary magnetic clouds with flux rope structures are an essential ingredient of space weather models. The main aim is to reconstruct their magnetic field topology and plasma properties and track their evolution in space and time. This has led to the implementation of a variety of flux rope configurations in magnetohydrodynamic models, with spheromak, modified spheromak, and more general toroidal flux ropes being commonly used.  The spheromak implementation in EUHFORIA (EUropean Heliospheric FORecasting Information Asset) brought to light different manifestations in the simulation domain of a phenomenon called the spheromak tilting (instability). The latter is caused by a torque that is exerted on the spheromak when its magnetic moment forms an angle with the ambient field. The torque forces the spheromak to rotate until it reaches a state of reduced magnetic potential energy. This is a simplified description of the fact that the Lorentz force exerted by the ambient magnetic field on the toroidal currents in the spheromak has in general a rotational component, resulting in a net-torque. As not only spheromaks but also other types of flux ropes carry toroidal currents, these should experience a torque as well. To what extent it affects their evolution is a matter of a game of forces. Being thus able to track the evolution (the position, orientation, etc.) of flux ropes is crucial. We have developed a tool to perform such a tracking for the spheromak implementation in EUHFORIA. The tool uses magnetic field and plasma threshold criteria to locate the spheromak and estimate its magnetic moment. It was originally developed and applied to spheromaks inserted in synthetic uniform ambient plasma and unipolar ambient fields that are realistic only locally along the spheromak trajectories. Since its initial development, the tool has been further improved and made capable of dealing with more realistic ambient field scenarios, containing current sheets and high-speed streams. 
Response of the Greenland Ice Sheet to temperature overshoot scenarios
Authors: Petrini Michele , Goelzer Heiko , Langebroek Petra , Rahlves Charlotte , Schwinger Jörg
Published: February 2023

As there is no evidence for the implementation of sufficiently ambitious global CO2 emission reductions, it is very unlikely that we will be able to keep the global mean warming at the end of the century below the 1.5 C limit set in the Paris Agreement. However, the development of CO2 removal techniques could potentially allow us to reach the 1.5 C target after a period of temperature overshoot, by offsetting past and current high levels of emissions with net-negative emissions in the future. To assess the effectiveness and the risks associated to such mitigation options, we need to better understand the impact of temperature overshoot scenarios on various components of the Earth System.  
Here, we focus on the Greenland Ice Sheet. We force an ice-sheet model (CISM2) with Surface Mass Balance (SMB) from an ensemble of 400 years-long idealized overshoot simulations, carried out with the Norwegian Earth System Model NorESM2. The SMB, which is calculated in NorESM2 using an energy balance scheme at multiple elevation classes, is downscaled during runtime to the ice-sheet model grid, thus allowing to account explicitly for the SMB-height feedback. In this presentation, we will assess the sea-level contribution of the Greenland Ice Sheet for overshoot pathways, compared to reference pathways without overshoot. Moreover, we will assess the impact of individual processes, such as the SMB-height feedback and the ocean-driven mass loss at marine-terminating margins, on the sea-level contribution of the Greenland Ice Sheet.  
Shallow deformation of the Mw 4.9 Khonj earthquake (6 January 2017) in the Zagros Simply Folded Belt, Iran
Authors: Fathian Aram , Tolomei Cristiano , H. Shugar Dan , Salvi Stefano , Reicherter Klaus
Published: February 2023

On 6 January 2017, an Mw 4.9 earthquake occurred c. 40 km northeast of the city of Khonj, in the Simply Folded Belt (SFB) of the Zagros, southwestern Iran. Using the JAXA ALOS-2 PALSAR as well as the Copernicus Sentinel-1 SAR images, we applied two-pass Interferometric Synthetic Aperture Radar (InSAR) to acquire the corresponding surface deformation of the Khonj earthquake. The fault plane solutions confirm the thrust mechanism for the earthquake that has a shallow depth of 5 km resulting in a subtle, permanent surface deformation visible through InSAR displacement maps. Concentric fringes on the interferograms in both ascending and descending geometries indicate the rupture has not reached the surface; nonetheless, they indicate shallow seismic deformation within the Zagros SFB. The Khonj earthquake is one of the smallest events with a discernible InSAR deformation field of c. 5–10 cm in the satellite line-of-sight (LOS). The epicenter of the earthquake is located in a plain between the northwestern and southeastern hinges of the Qul Qul and Nahreh anticlines. The source modeling from the InSAR data quantifies an NW-SE-striking fault either dipping to the northeast or the southwest. This shallow event is aligned with a zone in which the only documented surface ruptures in the Zagros—i.e., the Furg and Qir-Karzin earthquakes—are located.
Diurnal to interannual variability in Cabauw simulated by the ECLand land surface model
Authors: Fróis Luís , Miranda Pedro M. A. , Dutra Emanuel
Published: February 2023

Land surface plays a fundamental role in the earth system, mediating the water, energy and carbon fluxes between the land and the atmosphere. The land surface physical and biophysical processes act on time scales ranging from sub-daily to decades with relevant impacts from weather forecasts to climate change. However, there are very few available in-situ observations of land surface state and fluxes extending for several years to decades, limiting an integrated validation of the models on the different time scales. The long time series of Cabauw (Netherlands) observations provides a unique opportunity to evaluate land surface processes and their representation in land surface model at time scales ranging from sub-diurnal to interannual. In this study, we take advantage of the uniqueness of Cabauw observational record to investigate the performance of the ECMWF land surface model ECLand for the period 2001-2020 (20 years). Emphasis is given to the summer season and to evaporation and evaporative fraction. An idealized simulation without canopy resistance is performed along with other model configurations with changes to the constraints of canopy resistance (soil moisture availability and atmospheric humidity deficit) and the vertical discretization of the soil layers.Observational uncertainties impact the surface energy budget closure. For example, the model shows a large overestimation of the ground heat flux diurnal cycle. However, part of this can be attributed to observational uncertainties associated with the sinking of the temperature sensors.  The default configuration of ECLand shows an underestimation of latent heat and evaporative fraction, which can be partially attributed to the model’s representation of canopy resistance. The increased vertical discretization of the soil layers has a neutral impact on the simulated turbulent fluxes, showing an improved representation of near-surface soil temperature. Our results show limitations in the representation of the summer interannual variability of the turbulent fluxes. These are associated with the representation of extreme events (droughts) and are not fully addressed in any of the model configurations tested. These results suggest that other processes relevant to the representation of evaporation in dryness stress conditions need to be further investigated.This work was developed in the framework of the project NextGEMS funded through the European Union’s Horizon 2020 research and innovation program under the grant agreement number 101003470. Luis Frois was funded by the FCT Grant 2020.08478.BD. The authors also acknowledge the financial support of the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020- IDL.
Reversible-Jump, Markov-Chain Monte Carlo seismic tomographic inversion for anisotropic structure in subduction zones
Authors: Del Piccolo Gianmarco , VanderBeek Brandon , Faccenda Manuele , Morelli Andrea , Byrnes Joseph
Published: February 2023

The implementation of stochastic methods in seismic tomography arises as a response to the limitations introduced by traditional non-linear optimization solvers. Since tomographic problems are generally ill-conditioned, additional constraints on the model are set in the misfit function, and the weight given to each minimization term has a level of arbitrariness; different solutions are obtained with different choices for the damping/smoothing factors. Non-linear optimization solvers are based on a perturbative approach which linearizes the forward modelling locally around a reference model, updated at each iteration until convergence. These methods need the evaluation of the derivatives of the predictions with respect to the parameters of the model, which is not always an easy task, and they generally do not provide the uncertainties associated with the solution model.The Reversible-Jump Markov-Chain Monte Carlo is a stochastic method which performs a random walk in the model space sampling the posterior probability distribution associated with the model in the light of the observations. This method is a trans-dimensional Metropolis-Hastings where the number of parameters used to represent the continuous fields (as interpolation nodes) is treated as a parameter itself of the inversion, as the positions of the nodes. Using statistical estimators on the ensemble of models produced by the algorithm it is possible to extract a reference model, typically as an average of the ensemble. With this method no regularization is needed, and uncertainty can be estimated using the ensemble of models sampled. The limitations of non-linear optimization solvers are overcome at the cost of an increase in the computational time required.The presented applications of this method involve seismic tomography in subduction zones, where the anisotropic component of the seismic velocity field is relevant, and the inversion of seismological data could provide an interesting insight into the dynamics of these regions. 