bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of Snow Cloud Bands to Sea Surface Temperatures over Japan Sea
Authors: Sato Kaito , Inatsu Masaru
Published: March 2024

The response of snow cloud bands to the increase in sea surface temperatures (SSTs) over the Japan Sea was investigated. We focused on a typical snowfall event in Japan by intense cloud bands around a convergence zone on December 25, 2021. After confirming that a regional atmospheric model fairly reproduced the event, we conducted three sensitivity experiments replacing the initial and boundary values with air temperatures and/or SSTs uniformly increasing by 4 K. The results revealed that the model experiment with higher SSTs or lower air temperatures supplied more evaporation to the planetary boundary layer, which encouraged the higher cloud to along the convergence zone. This dominated the transversal mode (T-mode) of cloud bands in the east of the zone, diagnosed by a newly developed technique that discriminates it from the longitudinal mode (L-mode) by means of the absolute value of horizontal advection of hydrometers. In contrast, the experiment with lower SSTs or higher air temperature exhibited wider areas dominated by the L-mode cloud bands over the Japan Sea.
Nitrous oxide (N2O) emissions from a forested closed landfill site
Authors: Fraser-McDonald Alice , Boardman Carl , Gladding Toni , Burnley Stephen , Gauci Vincent
Published: March 2024

Many national governments, organisations and environmental groups have pledged to plant trees in an effort to increase carbon sequestration and mitigate climate change. Tree planting is commonly used as a restoration strategy for former landfill sites, and it is likely that many urban and urban-fringe areas, including closed landfills, will continue to be prioritised for tree planting in the coming years. Trees growing in natural and managed environments have the capacity to act as conduits for the transport of methane (CH4) produced belowground to the atmosphere. This process has also been observed in natural ecosystems for nitrous oxide (N2O) and we examined whether trees growing on closed landfills also mediate N2O emissions to the atmosphere. We investigated whether trees on a closed UK landfill site emitted more N2O than those on a comparable natural site. Measurements were made from stem and soil surfaces over a four-month period using flux chambers and Gas Chromatography. Results were then scaled up and the contributions of N2O stem fluxes to the total surface fluxes in different environments were compared. Analyses showed that stem and soil N2O fluxes from landfill were larger than from trees on the comparable non-landfill site. Tree stem N2O emissions on the former landfill also showed seasonal patterns and decreased with higher sampling positions above ground level. Findings indicated that tree stem N2O emissions accounted for less than 1% of the estimated total landfill surface flux, which was comparable to findings from a mesocosm study, but lower than estimates of the total N2O ecosystem flux in dry and flooded boreal forests (8% and 18%, respectively). Overall, this investigation suggested that trees planted on closed landfill sites may result in additional N2O emissions to the atmosphere, although the tree stem contribution to the total surface flux on the former landfill was a lower magnitude than that of fluxes previously reported from natural forested ecosystems.
A Software Toolkit for Advancing our Understanding of Land Surface Interactions: Recent developments to the SimSphere SVAT model
Authors: Lekka Christina , Petropoulos George P. , Anagnostopoulos Vasileios , Detsikas Spyridon E. , Katsafados Petros , Karympalis Efthimios
Published: March 2024

Mathematical models are widely used today to study the intricate physical processes and interactions among the different components of the Earth’s system. Such models are often used synergistically with Earth Observation (EO) data allowing to derive spatiotemporal estimates of key parameters characterising land surface interactions. This synergy allows combining the horizontal coverage and spectral resolution of EO data with the vertical coverage and fine temporal continuity of those models. SimSphere is a mathematical model belonging to the Soil Vegetation Atmosphere Transfer (SVAT) models. As a software toolkit, it has been developed in Java and it is used either as a stand-alone application or synergistically with EO data. The model use is constantly expanding worldwide both as an educational and as a research tool. Herein we present recent advancements introduced to SimSphere. We have comprehensively tested and updated the model code and added new functionalities which are illustrated herein using a variety of case studies. For example, it presents herein the new functionality that allows it to be applied over complex/heterogeneous landscapes, and this new model capability is demonstrated in experimental settings in various European ecosystems. The present study contributes towards efforts ongoing nowadays by the users' community of the model and is also very timely, given the increasing interest in SimSphere particularly towards the development of EO-based operational products characterising the Earth’s water cycle.  The research presented herein has been conducted in the framework of the project LISTEN-EO (DeveLoping new awareness and Innovative toolS to support efficient waTer rEsources man-agement Exploiting geoinformatiOn technologies), funded by the Hellenic Foundation for Research and Innovation programme (ID 015898). Keywords: SVAT, SimSphere, Earth Observation, land surface interactions, LISTEN-EO
A meta-analysis addressing the effects of eucalypt plantations on soil invertebrate density and diversity
Authors: Juan-Ovejero Raquel , Bartz Marie L.C. , Baretta Dilmar , Sousa José Paulo , Ferreira Verónica
Published: March 2024

Eucalypt plantations may have negative consequences on soil properties, yet a comprehensive understanding of their impact on soil invertebrate communities is lacking. This knowledge gap constrains our ability to unravel the potential effects of these fast-growing plantations on soil functioning. Hence, to analyze the overall impact of eucalypt plantations on soil invertebrates and to determine the main factors influencing these effects, we conducted a meta-analysis of studies comparing eucalypt plantations with different land use types (i.e. native forests, other forestry plantations, croplands, grasslands, integrated production systems, and invasive copses). We assessed their effects on both the density (analyzing 26 studies with 143 comparisons) and diversity (examining 14 studies with 168 comparisons) of soil invertebrate communities. The impact of eucalypt plantations on the density and diversity of soil invertebrate communities did not show statistically significant differences when considering all land use types together. However, the effects of eucalypt plantations on soil invertebrate density and diversity varied based on the specific land use types considered for comparison. The density was lower in eucalypt plantations relative to other forestry plantations but higher than in grasslands and integrated production systems. Contrarily, diversity was lower in eucalypt plantations compared to native forests but higher compared to other forestry plantations. Furthermore, the impacts of eucalypt plantations on soil invertebrates relative to other forestry plantations were influenced by factors such as the type of other forestry plantation (angiosperms versus gymnosperms), mean annual temperature, and annual precipitation of the study sites. These findings suggest that the effects of eucalypt plantations on soil invertebrate communities are context-specific and heavily influenced by the diverse characteristics of the different land use types considered for comparison. Taking into account the specific management practices and environmental conditions within eucalypt plantations and other land use types can provide insight into how alterations in land cover affect soil invertebrate communities.
Constraining the Thickness of the Conductive Portion Europa's Ice Shell using Sparse Radar Echoes
Authors: Schroeder Dustin , Wolfenbarger Natalie , Steinbrügge Gregor
Published: March 2024

Ice penetrating radars are intuitively appealing for probing ice shells because it is perceived as a way to directly imaging the ice/ocean interface or as a way to "picture" and interpret visually the structural  cross-section of the ice. While this approach is significant and can lead to substantial discoveries, it's also likely that many radar sounding measurements will not exhibit these obvious, intuitive features.Here, we address the potential of more subtle radar echoes (or the absence thereof) in providing valuable information. These echoes can impose constraints on ice temperature and thickness, offering insights similar to those obtained from other planetary geophysical methods like gravity science or magnetic induction measurements.In our study, we examine four potential radar signatures: pore-closure, eutectic melt, isolated echo detection, and attenuation horizons. We demonstrate that each of these signatures, by providing observational constraints on either the temperature or the integrated two-way attenuation at a given depth, can help determine the thickness of the conductive portion of Europa's ice shell.By integrating these findings with other geophysical approaches (e.g., gravity, magnetics), radar sounding data can significantly enhance studies and models of the ice-shell interior, even without the direct detection of the ice/ocean interface. 
Improving Flood Mapping Capabilities and Hydrological Model Calibration in India through the Surface Water and Ocean Topography (SWOT) Mission
Authors: Patidar Girish , Indu Jayaluxmi , Karmakar Subhankar
Published: March 2024

Even though altimetry has redefined our understanding of global rivers and lakes, the sparse temporal sampling of altimeters is often a cause of concern for many applications. This study explores the efficiency of temporal sampling offered by the recently launched Surface Water and Ocean Topography (SWOT) mission for hydrological applications over India. In particular, two research hypotheses are being investigated, namely a). Potential of SWOT data for enhancing flood mapping capabilities across India and b) Impact of SWOT-based discharges for calibrating a hydrological model calibration. Toward answering the first hypothesis, we considered a hypothetical launch date for SWOT, generating overpass data based on the mission's spatiotemporal orbital configuration. These overpass data were then compared with flood-affected areas identified in the Indian Flood Inventory (IFI) data to assess SWOT's potential for flood mapping. Results show that the spatio-temporal resolution of SWOT facilitates the monitoring of diverse proportions of Indian districts based on the cycle. More specifically, 0.67%, 15.79%, 29.24%, 45.54%, and 8.06% of Indian districts have one, two, three, four, and more than four observations per SWOT cycle (~21 days), respectively. To evaluate the second hypothesis, namely, the feasibility of SWOT discharge in hydrological model calibration, we created proxy-SWOT data by sampling in-situ data in accordance with the SWOT orbit configuration. Subsequently, errors were introduced into the in-situ gauge data based on recommendations from the SWOT science team. Results are presented over selected case study region of the Mahanadi river basin in India.
Less than 4% of dryland areas will desertify due to climate change.  
Authors: zhang Xinyue , Evans Jason , Burrell Arden
Published: March 2024

Drylands with low biological productivity are more fragile compared with non-drylands, making many human activities within them sensitive to long-term trends. Any negative trend in dryland condition is considered desertification. The Aridity Index, widely used to define drylands, indicates increasing aridity in the drylands over several decades, which has been linked to increasing occurrence of desertification. Future projections show continued increases in aridity due to climate change, suggesting that drylands will expand. However, satellite observations show a general greening of the drylands. Given the past inconsistency between the Aridity Index changes and observed vegetation changes, future evolution of vegetation productivity within the drylands remains an open question. Here we use a data driven approach to estimate the state of vegetation in the drylands and project their future changes. Results shows most of the global drylands are projected to see an increase in vegetation productivity due to climate change through 2050. The general increases are in-part due to CO2 fertilization effects and are in-line with recent trends and continue the past inconsistency with changes in the Aridity Index. Climate change negates the changes in at most 4% of global drylands to produce desertification. These regions include parts of north-east Brazil, Namibia, western Sahel, Horn of Africa and central Asia.
Response of the SMoothed Hybrid sigma-pressure (SMH) coordinate to higher-resolution topographic data in Korean Integrated Model (KIM)
Authors: Kong Hae-Jin , Park Ja-Rin , Nam Hyun
Published: March 2024

Korea Institute of Atmospheric Prediction Systems (KIAPS) has developed a global forecasting system, Korean Integrated Model (KIM) and the model now operates with 12-km horizontal resolution. With plans to develop the numerical model in horizontally and vertically higher resolution, smoothed hybrid sigma-pressure (SMH) coordinate has applied to KIM to cover the influence of the terrain structure. The SMH is proposed to alleviate artificial circulations that horizontal pressure gradients and advection can be appeared along complex surfaces by reducing small-scale components more rapidly with height (Choi and Klemp, 2021). In this research, we focus on the prediction with higher-resolution topography in the SMH coordinate and it is revealed that more realistic data can be utilized than the previous topography adapted in hybrid sigma coordinate. The SMH coordinate could well reflect the steepness and roughness of complex region such as terrains near mountains without stability issue. To investigate the sensitivity to the detailed topographic data, case studies such as heatwave, cold surge and rainfall are dealt with especially in the Korean peninsula consisted of complex terrain. By considering more complex topography, the SMH coordinate performs better in capturing precipitation peak and temperature bias. In addition, it will be discussed that vertical propagation to the upper atmosphere is appropriately controlled due to the SMH coordinate. This study can contribute to the future work on adjusting diffusion coefficient by optimizing the SMH coordinate in much higher resolution.
Recipes for a Hadean Earth
Authors: Mojzsis Stephen J. , Medvegy Anna
Published: March 2024

Silicate+metal worlds like Earth form hot owing to gravitational heating from accretion and differentiation, and intrinsic radioactive decay. Concurrent cooling sets off a chemical and mechanical cascade wherein siderophile elements (Fe+Ni) form a metallic core, and lithophile elements (Mg, Si, Al, Ca, Na, etc.) partition into mantle and siliceous crust. The outcome is a rocky surface beneath an outgassed fluid envelope composed of atmophile elements and compounds (CO2, H2O, H2, etc.). In its first 500 Myr (q.v. Hadean eon), Earth’s crust co-existed with liquid water; it was molded by volcanism, affected by late accretion bombardments and harbored diverse hydrothermal systems. Volcanism and differential buoyancy of the crust mandates the presence of scattered emergent landmasses. Such Hadean surfaces could host diverse (sub-)aqueous where organic chemical ingredients became concentrated to reactivity beneath a dense atmosphere bathed by the active young Sun. Soon after planet formation, it seems proto-biochemical reactions led to full-fledged living biochemistry. We do not know whether the earliest environments for life were ideally suited for its origin, or merely just good enough to accomplish the task. The inferred complexity for even the minimum biological entity means that operative and persistent biochemistry are the most difficult developmental stages to reach.
The impact of climate change on meteorite finds in East Antarctica
Authors: Tollenaar Veronica , Zekollari Harry , Kittel Christophe , Farinotti Daniel , Lhermitte Stef , Debaille Vinciane , Goderis Steven , Claeys Philippe , Joy Katherine Helen , Pattyn Frank
Published: March 2024

Antarctica is the most prolific place on Earth to find meteorites, which provide unique insights in the formation and evolution of our Solar System. Over 60% of all meteorite finds on Earth stem from so-called blue ice areas in the interior of the (East) Antarctic ice sheet. In these blue ice areas, a redirected ice flow and meteorological processes lead to the removal of surface layers. Meteorites once embedded in these layers of ice that are removed become exposed at the surface in high concentrations and are easy to spot in the field thanks to their contrasting dark color on blue ice. However, no meteorites have been found in areas where temperatures are relatively high. The absence of meteorites in these areas is explained by the fact that meteorites warm up under solar radiation, and as such these stones can melt the underlying ice, even when surface temperatures are well below zero. This very local melt causes the meteorite to move vertically downward into in the ice sheet, disappearing from the surface and hence impossible to see by eye and collect. Hence, in a warmer climate, meteorites are more prone to become unrecoverable. Using a data-driven approach, we estimated that with the currently increasing surface temperatures, meteorite loss rates exceed recovery rates multiple times. To estimate this loss rate, we first performed regional climate model simulations, for a low and a high emission scenario, in which blue ice areas are prescribed. Next, we fed this data to a machine learning algorithm that identifies meteorite-rich sites using over 12,000 known meteorite finding locations and their corresponding properties such as ice flow velocity and surface temperature. Until mid-century, projected losses are identical for the emission scenarios, after which losses are reduced for the low emission scenario and nearly constant for the high emission scenario. These meteorite losses demonstrate a (previously unnoticed) climate sensitivity of the interior of the Antarctic ice sheet. With temperatures remaining well below zero, even with several degrees of warming, meteorites are affected even by very minor (decimal) increases of surface temperatures during exceptionally warm events, which are expected to occur more frequently.
The long-lasting exhumation history of the Ötztal-Stubai Complex (Eastern European Alps): New constraints from zircon (U-Th)/He age-elevation profiles and thermo-kinematic modeling
Authors: Hölzer Kyra , Wolff Reinhard , Hetzel Ralf , Dunkl István
Published: March 2024

The Eastern European Alps formed during two orogenic cycles, which took place in the Cretaceous and Cenozoic, respectively. In the Ötztal-Stubai Complex – a thrust sheet of Variscan basement and Permo-Mesozoic cover rocks – the record of the first (Eoalpine) orogeny is well preserved, because during the second (Alpine) orogeny the complex remained largely undeformed. We use new zircon (U-Th)/He (ZHe) ages and thermo-kinematic modeling to constrain the cooling and exhumation history of the central part of the Ötztal-Stubai Complex since the Late Cretaceous. The ZHe ages from two elevation profiles increase over a vertical distance of 1500 m from 56±3 to 69±3 Ma (Stubaital) and from 50±2 to 71±4 Ma (Kaunertal), respectively (Hölzer et al., accepted by Lithosphere). These ZHe ages and few published zircon and apatite fission track ages were used for inverse thermo-kinematic modeling. The modeling results show that the age data are well reproduced with a three-phase exhumation history. A first phase with relatively fast exhumation (~250 m/Myr) during the Late Cretaceous ended at ~70 Ma and is interpreted to reflect the erosion of the Eoalpine mountain belt. As Late Cretaceous normal faults occur at the margins of the Ötztal-Stubai Complex, normal faulting may have also contributed to the exhumation of the study area. Subsequently, a long period with slow exhumation (
Recent developments integrating connected non-lotic and ephemeral water bodies into the Pulse-Shunt Concept
Authors: Maavara Taylor , Aho Kelly , Brinkerhoff Craig , Logozzo Laura , Brown Lee , McDowell William , Raymond Peter
Published: March 2024

River networks have been conceptualized as “leaky pipes” for carbon loss. However, there remains considerable uncertainty regarding where, when, and how carbon loss takes place along the aquatic continuum across hydroclimatic conditions. Recent modelling efforts have been developed to (1) connect river reaches with non- or semi-lotic systems including lakes, reservoirs, floodplains and wetlands, and (2) account for river network connectivity via quantification of ephemeral streamflow. These models, which use techniques such machine learning to scale from local measurements to high-resolution river network data products, enable the quantification of relative carbon loss fluxes in lentic vs. lotic systems across stream orders (“where”) within standardized hydroclimatic scenarios representing the full continua of flows and seasonal conditions possible within a watershed (“when”). These models further quantify carbon uptake via both biomineralization and photomineralization (“how”). We frame findings into an updated conceptual model of the Pulse-Shunt Concept, which builds on the representation of river networks as leaky pipes by correlating the “leakiness” with dependence on flow and stream order. We suggest that lakes and other lentic systems should be considered as reactivity “nodes” interspersed along mostly unreactive or passive river reaches. We additionally discuss how these river network modelling approaches can continue to be improved using sensor networks.
A quantitative analysis of monitoring signals and eruption explosivity
Authors: Contla Hernandez Brenda , Whitehead Melody , Bebbington Mark , Rowe Michael
Published: March 2024

Volcanic hazards are dependent on eruption size and explosivity, thus, the forecasts of these is crucial for emergency management decisions. Monitoring a volcano potentially offers valuable insights to assess when, where, and how explosive a future eruption might be. Data are collected from various monitoring equipment, such as seismometers, tiltmeters, and thermometers, that are installed at different locations and distances, from near-vent to satellite. However, establishing direct links between monitoring signals and even eruption onset remains challenging, especially for volcanoes lacking recent eruptions or without monitoring equipment installed prior to eruption. This challenge extends to eruption explosivity, where establishing links becomes even more difficult.The Global Volcanism Program (GVP) has compiled monitoring data in bulletin reports recorded by observatories and research institutions. These reports start from 1968 and summarise volcanic activity that occurs before, during and after an eruption. Importantly, these reports include descriptions about activity and/or raw data (number of earthquakes, frequencies, plots of the seismic signals or displacements on tiltmeters) from various monitoring equipment, providing a general understanding of precursor activities preceding an eruption. This is potentially key information for forecasting eruption explosivity.This study aims to establish a quantitative link between monitoring signals and eruption explosivity across multiple volcanoes. Data are compiled from 23 volcanoes worldwide, utilising information from the Global Volcanism Program (GVP) database and local volcano observatory reports where accessible. The different descriptions obtained by each class of monitoring equipment—whether seismic, thermal, deformation, SO2 fluxes, or crater alterations—will be statistically categorized and calibrated into predictor variables to be used in machine learning algorithms. We hope to develop a procedure for estimating the explosivity of the next eruption, as a step towards statistically forecasting future eruption styles.
Quantifying the moisture and precipitation sources over Northwest China and investigating the source differences in dry and wet summer seasons
Authors: Qian Peng
Published: March 2024

The northwest China (NWC) is situated in an arid and semi-arid inland, rendering its ecosystem highly susceptible to precipitation changes. Previous studies have revealed the wetting trend and potential moisture sources of the NWC, while not clearly quantified the moisture (water vapor and precipitation) sources and its interannual variability. Here, by performing and analyzing CAM5.1 simulation for 40 years, with a coupled atmospheric water tracer algorithm (AWT), we find that the dominant sources of summer moisture over NWC are from terrestrial sources (81.8% of vapor and 77.4% of precipitation), i.e. from the North Asia (NA), Europe (EUP), southern Tibetan Plateau (STP), and southeastern China (SEC), rather than the oceanic sources. Due to the influence of synoptic patterns, the precipitation-conversion efficiency of water vapor from the southwest airflow (STP and SEC) is higher than that from the northwest airflow (NA and EUP). We also find that despite a general increasing trend in humidification, the fluctuation from relatively dry to wet years still persists in the NWC influenced by the increased transport of moisture from terrestrial sources (NA and STP).
Hydrological connectivity dynamics in a mixed land use lowland catchment drive intra- and inter-annual variation in water quality in an intermittent stream network under drought conditions
Authors: Wang Famin , Tetzlaff Doerthe , Freymueller Jonas , Soulsby Chris
Published: March 2024

This study investigates the spatio-temporal dynamics of water quality in a 70 km2 mixed land use, lowland catchment in NE Germany over a four-year period (2018-2022). During this period with a consistent negative rainfall anomaly compared to the long-term average, the intermittent stream network exhibited three distinct hydrological phases each year, with important implications for water quality. Autumn and early winter featured a connecting phase, where spatially variable stream flows responded to rising water tables following increased rainfall and reduced evapotranspiration. The winter and early spring saw a fully connected phase, marked by increased stream flows throughput the catchment. Late spring and early summer experienced a disconnecting phase as flow gradually reduced and stopped in various parts of the catchment before ceasing altogether. A peat wetland in the centre of the catchment exhibited both the earliest and latest stream flows.Water quality was characteristic of a eutrophic lowland catchment and displayed spatial variations linked to catchment soils and land use. During the connecting phase, stream water quality mirrored that of groundwater and saw mobilization of dissolved organic carbon from wetland areas. In the fully connected phase, stream water became enriched with contributions from soil water and a higher nitrate load from agricultural areas. The disconnecting phase was characterized by lower flows and higher temperatures, contributing to increasingly anoxic conditions which saw nitrate reduction, mobilization of redox elements (Fe and Mn) and release of P. Intermittency caused a transition in stream water quality from hydrological process control in the connecting phase to joint control of hydrological and biogeochemical processes in the fully connected phase and then to biogeochemical process control in the disconnecting phase.Inter-annual water quality variation was associated with hydroclimate and catchment wetness dynamics, involving flushing and accumulation. Considering intermittency as an influencing variable changed the inter-annual characteristics of flow-concentration relationships compared with the previous perennial river stage, especially for nitrate. These findings have significant implications for the ecology and management strategies in similar catchments, highlighting the need to consider the seasonal hydrological phases for effective water quality management and ecological preservation.
Assessing lagged convective-scale weather ensembles for improved flood forecasting in fast-responding catchments 
Authors: Cattoën Céline , Ramos Maria-Helena , Peredo Daniela , Moore Stuart , Carey-Smith Trevor
Published: March 2024

High-resolution ensemble weather forecasts are essential for forecasting floods in complex topography with fast-responding catchments. However, they are computationally expensive. This study explores a cost-effective alternative via the use of time-lagged ensembles, defined as ensemble forecasts from the same model initialised at different times but verifiying at the same time.We evaluate lagged ensemble products, with varying configurations and proportions of lagged members, constructed from convective-scale numerical weather predictions (NWP) ensembles to forecast extreme flood events for fast-responding catchments. We compare four lagged products for two extreme event case studies in France and New Zealand. Lagged NWP ensemble products are used to drive hydrological models and evaluate flood forecasts across a range of performance evaluations based on traditional event-based metrics and user-focused strategies. We construct forecast diagrams and associated metrics based on the Brier Score for varying flood threshold severities to evaluate anticipatory and overly alarmist predictions.  Comparisons with a control burst ensemble (without any lagging) reveal that flood forecasts derived from lagged convective-scale NWP ensembles have the potential to better capture extreme flood events, albeit with some limitations. Benefits vary with time and lagged product configuration, but generally, lagged ensemble products match or surpass their control counterparts, particularly in spread-skill, anticipatory prediction of a severe flood threshold, and consistency of forecasts -- critical to retaining trust from the emergency management sector. However, lagged products tend to increase overly alarmist predictions at early forecast ranges but become a more effective strategy at longer ranges over a larger region.Utilising forecast diagram metrics based on the Brier Score allows the evaluation of multiple basins and ensemble products, incorporating an end-user-focused perspective for decision-making, such as anticipation of flood exceedance thresholds. The results provide valuable insights into lagged convective-scale weather ensembles' potential benefits and limitations in enhancing flood forecasting accuracy and reliability.
An Investigation into the Role of the Ocean for Seasonal Predictability of European Windstorms
Authors: Ng Kelvin S. , Leckebusch Gregor C.
Published: March 2024

Extreme extra-tropical cyclones and related windstorms are the most dangerous and costly meteorological hazards in Europe. The latest state-of-the-art seasonal forecast suites show now usable forecast skill for basic parameters like mean temperature or precipitation for mid-latitude Europe on lead times of up to 4 months (Nov-Feb). One avenue for skilful prediction of extremes is the now-proven forecast skill for large-scale climate modes, as these directly influence extreme windstorms. Improved ability to simulate successfully the relevant large-scale climate patterns like e.g., the North-Atlantic Oscillation, the East-Atlantic pattern, and/or the Scandinavian pattern opens up a prominent route to progress the forecast skill for extreme storms.Nevertheless, recent publications have shown that even in the current model suites, the existing skill for forecasting the frequency or intensity of windstorm tail events, is not fully explained by those dominant large-scale variability patterns. Furthermore, studies revealed a potential connectivity of storm count predictions to stratospheric sudden warming events and also highlighting the influence of atmosphere-ocean coupling. Recent developments in the forecast skill of the upper-ocean heat content and the role of re-emerging temperature anomalies for the European winter climate allow to explore another pathway with potentially predictive power, the role of ocean-atmosphere interaction. Ocean-atmosphere interaction caused e.g., by the NAO have been increasingly recognised but have not been systematically linked to the ability to predict extreme severe windstorms on a seasonal time scale. In this presentation, we will present preliminary results of the role of ocean on the predictability of European windstorms.
Vulnerability functions based on insurance data for wind, precipitation, hail and flood damages for residential and commercial buildings in the Netherlands
Authors: van Ederen Daan , Botzen Wouter , Aerts Jeroen , Lupi Veronica , Scussolini Paolo , de Moel Hans , Gubbels Koos
Published: March 2024

Global warming is changing the climate and causing more frequent extreme weather events, such as floods and precipitation extremes. Future financial losses are expected to rise further due to a continued increase in economic exposure to intensifying extremes. As a result, climate change is recognized as an important source of risk for financial institutions. Insurance companies use natural catastrophe models to estimate the expected climate-related risk (in terms of losses) of their non-life insurance portfolios. Within these models, the vulnerability function describes the susceptibility of objects to  damages from natural hazards, which is of fundamental importance to the sound estimation of natural catastrophe losses. This paper constructs empirically based vulnerability functions for natural catastrophe models that estimate wind, precipitation, hail and flood damages for distinct object classes (i.e., residential and multiple commercial building types). For this, we leverage a unique insurance dataset from Achmea with high quality damage claims for different perils. This dataset contains the claim amount, building reconstruction value, location and multiple building characteristics (e.g., building use and material) at the object level for more than half a million claims over the past 40 years in the Netherlands. The vulnerability functions describe multivariate relationships between the damage ratio of objects and one or multiple natural hazard intensity measures (e.g. wind speeds and direction), primary and secondary modifiers (i.e., building characteristics). In addition, both confidence and prediction intervals are constructed. This study innovates upon the literature by using large samples of high quality damage claims data to estimate vulnerability functions for multiple natural catastrophes and object classes in the Netherlands. Our analysis pays special attention to model assumptions, the goodness-of-fit and uncertainty intervals. The results can serve as inputs for public, academic and open-source natural catastrophe models to facilitate the estimation of accurate natural catastrophe damages now and in the future. 
Radiocarbon Inventories of Switzerland (RICH): Investigations into fossil CO2 emissions from cement factories and urban areas
Authors: Geissbühler Dylan , Laemmel Thomas , Gautschi Philip , Wacker Lukas , Szidat Sönke
Published: March 2024

The RICH (Radiocarbon Inventories of Switzerland) project aims to build the first database and model of the distribution and cycling of 14C at a national scale across the atmosphere, soils, rivers and lakes C pools. The subproject presented here (RICH-Air) will serve to construct complementary monitoring and snapshots approaches of atmospheric 14CO2 measurement in this larger scope.Radiocarbon measurements of atmospheric CO2 provide unique information on its sources and subsequent transport. It allows the apportionment between biogenic and fossil sources, which are close to the contemporary atmospheric background and 14C-free, respectively. The determination of the fossil CO2 fraction in air samples, can be used to identify fossil fuel emission patterns from a local to a regional scale. These efforts can then be used to plan and enforce future CO2 emissions mitigation steps.Presented here are preliminary results from investigations regarding the fossil factor in emissions of 3 Swiss cement factories and the urban area of Bern, Switzerland. The radiocarbon content of emissions were studied in multiple ways:Direct and downwind measurement of 14CO2 emissions at cement factories
Measurement of 14C content in tree leaves around cement factories and the urban area of Bern
The 14CO2 results show that downwind emissions from cement factories are only accurate if the choice of local background is appropriate. Measured values, both direct and indirect, show that the fossil fraction of emissions is at least of 2/3, which is within the theoretical range for cement production. Also, different facilities seem to have contrasting mean fossil content in their emissions, probably due to their individual fuel mix. Finally, leaf samples show a gradient in 14C values, more depleted closer from the source, both for cement factories or the urban area, which is consistent with previous studies.
Dansgaard-Oeschger events in a box ocean model
Authors: Ganopolski Andrey
Published: March 2024

A generic nine-box ocean model (GNOM) is developed to study the stability and variability of the Atlantic Meridional Overturning Circulation (AMOC). Using this model, it is shown that centennial to millennial time scale self-sustained oscillations in AMOC strength and associated climate characteristics resembling temporal dynamics of observed Dansgaard-Oeschger events appear within a certain range of the boundary conditions (temperature and freshwater flux). Adding white noise to the system makes such oscillations more robust, i.e. they occur within a larger area in the phase space of temperature-freshwater forcing. However, regardless of the model’s parameters and boundary conditions, the typical periodicity of such oscillations is about 1000 years, which is much shorter than the typical recurrence time of observed  Dansgaard-Oeschger events. Only after adding an interaction with an additional component, which has a longer internal time scale and mimics the response of the surrounding ice sheets, do much longer self-sustained oscillations of AMOC arise.  
Transforming river morphology over 60 years of urban development 
Authors: Ashmore Peter , Victoria Barlow , John McDonald
Published: March 2024

Urban land development causes changes to river channel form and function and to community relationships and visions of rivers.  The story of urbanization of Highland Creek, Toronto, Canada involves the transformation of the 100km2 watershed from rural to almost 100% urban land-use over 6-7 decades. The unusually rich documentation of the watershed changes allows for understanding of the long-term trajectory of transformation of the channels based on geomorphic principles. It also shows the evolving institutional responses to managing and redesigning the river channels and valleys, and mitigating risks, which can be seen as part of the urbanization of rivers along with the physical response of the river channels. Urbanization has transformed the main channels to an extremely energetic state more like mountain streams despite the low relief terrain of the Toronto region with total stream power increasing by up to 10 times following urbanization. Measurements from historical air photos for multiple epochs over 60 years show that channels have widened progressively by a factor of 4 or 5, with accompanying changes in planform, triggered, in particular, by two or three large flood events, and consistent with hydraulic geometry predictions. The time trajectory and spatial pattern of changes to morphology of reaches that were free to adjust to the increased stream power are well-predicted by land-cover based predictions of stream power using the SPIN watershed analysis tool (Stream Power Index for Networks) which provides a means of predicting possible future changes as well as explaining historical change.  Increases in specific stream power show potentially large increases in bed material particle mobility consistent with observed morphology changes. Freedom to evolve to a new state is partly the result of institutional decisions and vision to set aside valley land in the 1950s to reduce flood damage. In other places the process of urbanization has involved progressive engineering of the channel, reflecting approaches in 1960s and 70s to protect infrastructure and institute an engineering vision of river control which has eliminated fluvial processes of channel development and adjustment. Recent moves to channel restoration using geomorphic design approaches reflect create novel river morphology. Urbanization of channels does not end with land cover change and its physical hydro-geomorphic effects, nor is there a clear end-point and time-span of response that is often claimed in studies of urban fluvial change. Understanding urbanization as an ongoing process of ‘re-storying’ river channels within a socio-geomorphic system is essential to understanding urban river histories and futures, explaining urban river morphology, and recognising the entwined physical and socio-political power and processes that transform urban rivers.  
Process-based analysis of the MJO phase speed error in the coupled NWP model of the UK Met Office: a two-way feedback between the MJO and the diurnal warm layers
Authors: Karlowska Eliza , Matthews Adrian , Webber Benjamin , Graham Tim , Xavier Prince
Published: March 2024

The diurnal cycle of SST (dSST) is influenced by the development of diurnal warm layers in the upper ocean. Observations show that the dSST rectifies intraseasonal SSTs, potentially leading to changes in intraseasonal weather patterns such as the Madden-Julian Oscillation (MJO). Here we analyze 15-day forecast composites of the coupled ocean-atmosphere and the atmosphere-only configurations of the Numerical Weather Prediction (NWP) models of the UK Met Office to show that a strong dSST in the coupled model leads to a faster MJO propagation compared with the atmosphere-only version of the model. A set of experiments using the coupled model was designed to reduce the strength of the dSST by imposing instant vertical mixing in the top 5 and 10 m of the ocean model. On a 15 lead-day time scale, weakening the dSST slows the MJO phase speed in the coupled model. On a 7 lead-day time scale, all coupled model runs display an underlying 5% increase in the MJO phase speed compared to the atmosphere-only model due to the presence of thermodynamic coupling unrelated to the dSST. The MJO phase speed increase due to the dSST is linearly related to the mean tropical dSST at lead day 1 in the coupled model. An additional 4% of the MJO phase speed increase between the control coupled model and the atmosphere-only model on a 7 lead-day timescale can be attributed to the presence of the dSST in the coupled model. Over 15 lead days, the coupled model produces a two-way feedback between the MJO and the dSST. The MJO conditions set the strength of the dSST in the coupled model. Consistent with observations, the dSST in the coupled model rectifies intraseasonal anomalies of SSTs such that stronger dSST leads to positive intraseasonal SST anomalies. The MJO convection response to these SST anomalies peaks 7 days later, and subsequently feeds back onto SST anomalies. The phase relationship between MJO convection, dSST and intraseasonal SST anomalies is consistent with the relationship between dSST and MJO propagation speed. Overall, our experiments demonstrate the importance of high vertical resolution of the upper ocean in predicting the eastward propagation of the MJO in an NWP setting, potentially creating repercussions for seasonal predictions and climate projections should this feedback be unrepresented in the models.
Towards calibration of GNSS receiver hardware delays for improving geodetic reference systems through clock ties. A requirements analysis for developing a GNSS pseudolite transmission chain
Authors: Lăpădat Alexandru Mihai , Kodet Jan , Pany Thomas
Published: March 2024

The growing demand for Earth science applications poses challenges in improving geodetic reference frames. Systematic errors currently restrict the accuracy of these frames because the classical geometric ties between multiple geodetic techniques fall short of sufficiency. Our objective is to identify and analyze the impact of variable GNSS receiver hardware delays (incl. antenna-hardware delays) on carrier-phase time transfer with an accuracy of picoseconds/millimeters. We propose using a ground-based GNSS pseudolite system synchronized to an optical timing system (clock tie) developed at the Geodetic Observatory Wettzell to calibrate the variable hardware delays and facilitate a closure in time between multiple geodetic techniques.This study analyzes the requirements for developing a GNSS pseudolite and its transmission chain. We reformulate the classic iono-free Precise Point Positioning (PPP) mathematical theory to incorporate pseudolite data, separating the known receiver clock error from unknown transceiver hardware delays. The analysis suggests a preference for highly directive and mechanically stable Right Hand Circularly Polarized (RHCP) log periodic or helix transmission antennae. Calibration for Phase Center Offset (PCO), Phase Center Variations (PCVs) and careful installation to minimize multipath are crucial. This results in a carrier-phase observation model with three unknowns: transceiver hardware delays (our focus), frequency-dependent ambiguity terms, and low tropospheric delay influence.Utilizing a USRP-based transmission procedure, we successfully tracked an E1B Galileo signal replica with an in-house developed GNSS software-defined receiver (SDR). The transmission was implemented using two approaches: over-the-air and loopback. The over-the-air transmission was carefully planned using a link budget calculation to ensure that it did not exceed the allowed free-air transmission constraints. Empirical validation ensured a carrier-to-noise ratio (C/N0) below 30dB/Hz near critical public areas. In the loopback approach, the transmitted GNSS signal was fed into the local SDR within the pseudolite, sharing the same Analog-Digital-Converter (ADC)/ Digital-Analog-Converter (DAC)ADC/DAC, clock and local oscillators. In a future stage, this signal is supposed to be compared to a reference signal derived from the optical timing system. In our analysis, we also assessed the stability of the USRP frequency synthesizer, known as Phase Lock Loop (PLL), in the context of high-precision applications, such as real-time kinematic (RTK) positioning. We found that tuning the synthesizer in integer-n mode is crucial in maintaining a stable carrier frequency and achieving a 100% real-time kinematic positioning fixing rate. 