bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncertainty in delineation of peatland microcatchments
Authors: Johnston Adam , Shuttleworth Emma , Evans Martin , Allott Tim , Pilkington Michael
Published: March 2022

Microcatchments (<10 ha) are often used to monitor the effect of disturbances or restoration on the hydrological functioning of peatlands. Catchment areas serve as the spatial limits within which fluvial processes are studied and topographic parameters are derived. Digital Elevation Models (DEMs) and Digital Surface Models (DSMs) are used in standard practice to delineate the watershed boundary of microcatchments. These digital representations of topography contain errors, meaning the derived catchment areas have inherent uncertainty. The low-slope and hummock/hollow nature of peatland surfaces mean catchment delineation is particularly sensitive to vertical errors, so understanding the potential effect of uncertainty on the accuracy of catchment delineation is essential to providing a reliable account of peatland microcatchments hydrology.

This paper investigates the sensitivity of catchment delineation to DEM/DSM error for 30 peatland microcatchments across the Peak District National Park, UK. To evaluate the suitability of DSMs for hydrological applications in peatlands, a 0.25m photogrammetric DSM is used and evaluated against a 1m LiDAR DEM. Monte Carlo simulation is applied to produce a range of realisations of the DSM and DEM within their vertical error margins, from which a range of catchment areas are calculated. The variability of the watershed boundaries of each catchment is evaluated in the context of local gradient, difference from mean elevation and extent of gullying, to determine the relationship between terrain characteristics and variability in catchment delineation. Findings will have implications for the generation of catchment areas in peatland hydrology.  
Mediterranean Sea warming, nutrient decline, primary production increase, deoxygenation and acidification during the 21st century from high resolution physical and biogeochemical projections under emission scenarios RCP4.5 and RCP8.5
Authors: Reale Marco , Cossarini Gianpiero , Lazzari Paolo , Lovato Tomas , Bolzon Giorgio , Masina Simona , Solidoro Cosimo , Salon Stefano
Published: March 2022

Eddy-resolving projections of the physical and biogeochemical state of the Mediterranean Sea under the Representative Concentration Pathway (RCP) 4.5 and 8.5 are here analyzed to assess the impacts of climate change on the Mediterranean marine ecosystems in the middle and at the end of the 21st century. The projections were produced through the offline coupling between the physical model MFS16 and the transport-biogeochemical reactor OGSTM-BFM. The analysis shows during the 21st century an overall warming and an increase in the stratification of the water column, resulting in a weakening of the thermohaline circulation of the basin. The biogeochemical projections show a decline in the dissolved nutrients content and organic matter stock of the euphotic and intermediate layers of the basin and an increase in the net primary production and phytoplankton respiration. Moreover, the projected warming of the water column and the increase in the respiration community will drive a quite uniform surface and subsurface reduction in the oxygen concentration. Finally an acidification of the upper and intermediate layers of the basin driven by the CO2 absorption from the atmosphere is projected. All the projected changes are found to be stronger in the eastern part of the Mediterranean basin. 
A Bayesian hierarchical model of channel network dynamics reveals the impact of stream dynamics and connectivity on metapopulation
Authors: Durighetto Nicola , Bertassello Leonardo Enrico , Botter Gianluca
Published: March 2022

The active portion of river networks varies in time thanks to event-based and seasonal cycles of expansion-retraction, mimicking the unsteadyness of the underlying climatic conditions. These rivers constitute a major fraction of the global river network, and are usually referred to as temporary streams.
Channel network dynamics have significant implications in catchment hydrology an beyond, including ecological dispersion, stream metabolism and greenhouse gas emissions. Moreover, temporary streams provide a unique contribution to riverine ecosystems, as they host unique habitats that are capable of promoting biodiversity. Nonetheless, to date the complex ways in which the temporal dynamics of the active portion of a stream network affect ecological processes and ecosystem services are not fully understood. In this contribution, we present a stochastic framework for the coupled simulation temporary stream dynamics and the related occupancy of a metapopulation. The framework combines a stochastic model for the generation of synthetic streamflow time series with the hierarchical structuring of river network dynamics, to enable the simulation of the full spatio-temporal dynamics of the active portion of the stream network under a wide range of climatic settings on the basis of a limited number of physically meaningful parameters. The hierarchical nature of stream dynamics - which postulates that during wetting nodes are activated sequentially  from the most to the least persistent, and deactivated in reverse order during drying - represents a key feature of the approach, as it enables a clear separation between the spatial and temporal dimensions of the problem. The framework is complemented with a stochastic dynamic metapopulation model that simulates the occupancy of a metapopulation on the simulated stream. Our results show that stream intermittency negatively impacts the average occupancy and the probability of extinction of the focus metapopulation. Likewise, the spatial correlation of flow persistency along the network also bears a significant impact on the mean network connectivity and occupancy. This effect is particularly important in drier climates, where most of the network undergoes sporadic and flashy activations, and species dispersal is therefore inhibited by river fragmentation most of the time. The approach offers a robust but parsimonious mathematical framework for the synthetic simulation of the spatio-temporal dynamics of the active stream network under a broad range of climatic and morphological conditions, providing useful insights on  stream expansion and retraction and its ecological significance.
Damage and Dynamic Activity on the Thwaites Glacier Ice Tongue: 2015 to 2021
Authors: Surawy-Stepney Trystan , Hogg Anna E , Cornford Stephen L , Davison Benjamin J
Published: March 2022

The majority of ice mass loss in West Antarctica is due to the ejection of grounded ice into the sea via ice-dynamic processes. Structural changes that impact the flow speed of marine-terminating glaciers can, therefore, impact their contribution to global sea level rise. Thwaites Glacier is among those for which these considerations are particularly important, due to its potential connection to the stability of the West Antarctic ice sheet, and the structural changes that have been observed at its terminus in recent years. However, the interactions between ice structural properties and flow speed are not well established, partly due to the limited availability of coincident observations.

We present weekly ice velocity measurements, derived using Sentinel-1 radar data, showing the recent onset of episodic dynamic variability in the form of two large-magnitude ~30%-45% acceleration/deceleration events between 2017 and 2021, occurring across the majority of the remnant of Thwaites Glacier's floating ice tongue, before a relaxation to the 2015/16 mean speed. Using deep learning methods, we measured a synchronous decrease in the structural integrity of the ice tongue and its eastern shear margin during the study period, and the upstream propagation of these regions of damaged ice. The pattern of change seen in the concurrent damage and ice velocity observations suggests a link between the two, which we explore in the work. The existence of this link is further supported by ice flow modelling, carried out using the BISICLES ice sheet model, in which the spatial pattern and concentration of observed damage are closely reproduced when forced with the observed speed changes.

Our results add to the growing body of evidence that the extent and degree of damaged ice has a significant distributed effect on ice velocity, and further demonstrate that damage processes must be integrated in ice sheet models in order to make accurate predictions of long-term behaviour and sea level contribution.
Theoretical framework for environmental risk assessment due to Natech event
Authors: Giusti Riccardo , Arosio Marcello , Martina Mario
Published: March 2022

Natural hazards pose a significant threat to industrial areas and their surrounding environment, in particular considering that extreme natural events are expected to occur more frequently and exposure will increase due to urbanization growth. A NATECH event is defined as a NAtural hazard triggering TECHnological disasters which could affect people, the environment, other facilities and systems. NATECH research began less than thirty years ago and in the last decade these complex phenomena have been investigated by academia and industry. However, NATECH knowledge and methodology have some gaps that must be filled for better risk prevention and management. In fact, it is mainly focused on technological vulnerability or assessing its occurrence probability, yet possible consequences are only partial investigated. The aim of this study is to develop a theoretical framework to assess the environmental impact on soil and groundwater due to NATECH events triggered by flood. This is accomplished by harmonizing existing algorithms and methods for the natural and technological risk component with the new developed environmental soil and groundwater risk component into a coherent modelling chain. The proposed framework utilizes data from natural driven forces (e.g. flood height and velocity) and their probabilities of occurrence. These driven forces are applied to storage tanks through an existing vulnerability model. In order to evaluate resistance pressures, the model requires tank geometries and hypothetical filling level distribution. In addition, a simplified environmental risk model is applied at site scale depending on the stored product (e.g. gasoline, petroleum, etc.) in order to evaluate an affected area and its potential degree of contamination of soil and groundwater.  The proposed framework is applied to a realistic case study and results and critical points would be discussed. We believe that the general theoretical framework could be adapted to any natural triggering phenomena (e.g. earthquakes, lighting, etc.), in order to assess environmental impacts due to NATECH events.
APENA3 – Methodology and steps for the preparation of three pilot climate adaptation strategies and implementation plans in Ukraine
Authors: Tsompanidis Christos , Krakovska Svitlana , Lolos Theofanis , Sakalis Antonios , Ieremiadi Eleni , Gittelson Alex , Kysil Oksana , Krasnozhon Alla
Published: March 2022

APENA 3 ”Strengthening the capacity of regional and local administrations for implementation and enforcement of EU environmental and climate change legislation and development of infrastructure projects” is an EU-funded project, targeting to effectively raise Ukrainian public authorities capacities at local and regional level in designing and implementing key reforms. The main feature of Component 3 is the development of climate adaptation strategies followed by implementation plans for three Ukrainian Oblasts. Following an evaluation process, the Oblasts of Ivano-Frankivs’ka, L’vivs’ka and Mykolaivs’ka were determined to be the most appropriate in which to undertake the above activities. The first important step, was to identify the sectors of interest in relation to climate change, in Oblast but also National level utilizing the experiences and know-how from Europe and internationally, since the pilot Strategies and Implementation Plans, will be used as a guidance for other Oblasts in the future to elaborate regional climate adaptation planning. The selected sectors include agriculture, forests, biodiversity and ecosystems, water management, fisheries, coastal areas, tourism, critical infrastructure, energy, health, built environment and cultural heritage. The next step in the methodology is the vulnerability and risk assessment. The project team will identify the appropriate climate indices to evaluate vulnerability and risk based on specific climatic impact drivers for the respective sectors. Sensitivity and exposure analysis will follow in order to identify the degree of vulnerability of each sector and geographic area in the three pilot Oblasts. Based on the previous assessment, impacts will be identified and examined in terms of likelihood and severity, guiding the team to determine the risk. The various challenges (stakeholder engagement, sectoral issues identification, collection of climate data etc.) in the use of climate data will be identified and tackled in this stage. Following the preparation of the project’s scientific basis, the Experts team will determine sectoral adaptation thematic pillars, that will include horizontal and location specific measures and actions for the evaluated sectors.
A new conceptual model to explain the mid-Pleistocene transition
Authors: Legrain Etienne , Parrenin Frédéric , Capron Emilie
Published: March 2022

Pleistocene climate is primarily driven by changes of the Earth’s orbital parameters. However, the Mid-Pleistocene Transition (MPT) (~0.8-1.2Myr) which corresponds to a gradual change of interglacial-glacial cyclicity from weak 40kyr climatic cycles to the current strong 100kyr cycles, remains largely unexplained. So far, models only based on orbital forcing were not capable to reproduce this transition, discarding the hypothesis of an orbitally-driven transition. Internal Earth system climate causes were thus explored as primary drivers of the MPT, as a gradual decrease in atmospheric CO2 concentrations or the removal of the regolith beneath the northern hemisphere ice sheets. 
Here we present an improved version of the conceptual model of Parrenin and Paillard (2012) modelling ice volume variations over the past 2Myr. Our model switches between two states, a glaciation state and a deglaciation one, following a threshold mechanism related to the input parameters and the modelled ice volume itself. The modelled ice volume is compared to the ice volume reconstructions inferred from paleodata. 
 We reproduced the MPT using three different models. The “orbital” model which only use orbital forcing parameters as input. The “gradual” model, which is similar to the orbital model plus a continuous drop of a physical parameter in addition to orbital forcing parameters. The “abrupt” model, also similar to the orbital model plus a time-determined abrupt variation of a physical parameter in addition to orbital forcing parameters. 
For the first time, our conceptual model is able to simulate qualitatively the Mid-Pleistocene Transition with only changes in the orbital forcing parameters, reproducing the change in frequency and amplitude of the transition. Moreover, the hypothesis of a coupled influence of orbital forcing and a decreasing deglaciation threshold parameter is by far a better hypothesis than considering an abrupt change regarding our model results. In fact, the “gradual” model contains less parameters and a smaller data-model standard deviation of residuals than the “abrupt” model. Orbital forcing could thus have enabled the Mid-Pleistocene Transition. A combined influence with a decreasing parameter, such atmospheric  CO2 concentration, would have triggered this transition.

References 
Parrenin, F., & Paillard, D. (2012). Terminations VI and VIII (∼ 530 and∼ 720 kyr BP) tell us the importance of obliquity and precession in the triggering of deglaciations. Climate of the Past, 8(6), 2031-2037.
Fitting and extrapolation of transient behaviour in the presence of tipping points
Authors: Ashwin Peter , Bastiaansen Robbin , von der Heydt Anna
Published: March 2022

One of the key problems in climate science is to understand the asymptotic behaviour of a climate model, such as Equilibrium Climate Sensitivity (ECS), from finite time computations of transients of a model that may be complex and realistic. Typically, this is done by fitting to some simpler model and then extrapolating to an asymptotic state. But how do transients behave in the presence of tipping points? More precisely, how much warning can one get of an approaching tipping point? In this work we highlight an illustrative example showing how a good fit of a transient to a simpler model does not necessarily guarantee a good extrapolation, and discuss some other implicit assumptions that may arise when estimating quantities such as ECS.
Satellite investigations of glacial meltwater plumes
Authors: Edwards Laura
Published: March 2022

Calving at marine terminating glaciers accounts for at least 40 % of mass loss from the Greenland ice sheet, the current largest land ice sea level rise (SLR) contributor. Research suggests that glacier meltwater plumes play an important role in glacier calving front retreat and so studying their extent (2D and 3D) and temporal and spatial variability is critical for estimating potential SLR.

This work presents the novel use of satellite synthetic aperture radar (SAR) to study glacial meltwater plume extent and compares this approach to the more standard use of cloud and light-limited multispectral data for observations of plume extent. SAR data have often been used in oceanography to isolate ocean fronts, large-scale upwelling and estuarine plumes but have not thus far been used for studying glacial meltwater plumes. A SAR intensity image is retrieved from the backscatter signal which is a function of wind, wave and current interactions on a water surface, therefore, any ocean or river features which modify these have the potential to be identified within the SAR image. Higher resolution SAR data have more recently become available providing the opportunity to study meltwater plumes which present as an upwelling in the glacier fjord or lake in front of the glacier.

An initial study location of Breiðamerkurjökull glacier and Jökulsárlón proglacial lake, in Iceland, was chosen for the study which will involve fieldwork in 2022 to allow 3D analysis of plumes. This location is logistically easier and less expensive than Greenland yet provides an ideal analogue for study of Greenland glacier meltwater plumes in fjord-ocean systems. This is due to the connection of Jökulsárlón glacial lake water with the North Atlantic Ocean via a channel through which all tidal and residual flows in and out of the lake occur (Brandon et al., 2017) much like a glacier-fjord system in Greenland. Breiðamerkurjökull glacier calving front terminates in Jökulsárlón just like a marine terminating glacier in Greenland terminates in a fjord. Here initial results from quantifying the 2D extent of surface plumes using SAR are presented. 
Sub-hourly sea level quality-controlled dataset to quantify extreme sea levels along the European coasts
Authors: Balić Marijana , Šepić Jadranka , Ćatipović Leon , Čupić Srđan , Kim Jihwan , Međugorac Iva , Omira Rachid , Pellikka Havu , Ruić Krešimir , Vilibić Ivica , Zemunik Petra
Published: March 2022

Extreme sea levels can lead to floods that cause significant damage to coastal infrastructure and put people's lives in danger. These floods are a result of physical processes occurring at various time and space scales, including sub-hourly scales. To estimate the contribution of sub-hourly sea level oscillations to extreme sea levels, raw sea level data from about 300 tide gauge stations along the European coasts, with a sampling resolution of less than 20 minutes, were collected. The data were obtained from: (1) the IOC-SLSMF website (290 stations); (2) National agencies (Portugal, Finland, Croatia –24 stations). Portions of the raw dataset had various data quality issues (i.e., spikes, shifts, drifts) hence quality control procedure was required. Out of range values, values with a 50 cm difference from one neighbouring value or a 30 cm difference from both neighbouring values, were automatically removed. The automatic spike detection procedure was carried out by removing values that differed by three standard deviations from a spline fitted with the least squares method. Following the automatic quality control, all remaining data were visually examined and spurious data were removed manually.

The resulting data set contains sea level data from 2007. to 2021., with an average record length of approximately 7 years, however the length varies from a few months at some stations to 13 years at others. Tide gauges with longer records (>10 years) are based in the Baltic region, France and Spain, whereas the ones with shorter records (<3 years) are mostly based in the Eastern Mediterranean. The Western Mediterranean and western Europe have a high station coverage with records of various lengths. Tide gauges mostly provide data with a one-minute sampling frequency, however, some of them still record on a multi-minute scale (i.e., United Kingdom with 15 minutes and Norway and the Netherlands with 10 minutes sampling frequency).

Preliminary statistical analyses were done, resulting with spatial and temporal distribution of contribution of high-frequency sea level oscillations to total sea level extremes along the European coasts.
How differential biogenic sediment production impact the stratigraphic architecture of carbonate systems: a stratigraphic forward modelling study of Miocene Llucmajor platform. 
Authors: Tella Timothy , Winterleitner Gerd , Mutti Maria
Published: March 2022

Understanding the roles played by biota in the evolution of carbonate architecture requires integrating interdisciplinary datasets due to the complex interplay of biological, oceanographic, mineralogical and ecological factors that create stratigraphic and sedimentological changes in carbonate systems through geologic time. Stratigraphic forward modelling enables this approach by using mathematical equations, algorithms and empirical assumptions to numerically reproduce the processes and factors that acted over geologic time. One of the many factors that strongly influence stratigraphic heterogeneity and architectural evolution of carbonate systems is biogenic carbonate production, whose impact still requires detailed investigation. Hence, in this study we attempted to investigate, using stratigraphic forward modelling, the role of different biogenic sediments in the evolution of carbonate systems geometries using the Llucmajor platform as a reference case study.

We developed several forward models of the coral-dominated Llucmajor platform based on parameters from published outcrop and well data, as well as modern analogues. These models were validated through comparison with published outcrop and well data, leading to the reference model on which several sensitivity analyses were carried out. Carbonate production was modelled by creating five model sediment classes (massive corals, dish corals, reworked grains, and muds, and rhodalgal sediments) to reflect the biotic associations that have been interpreted from outcrops of the platform. These model sediments classes interacted with environmental parameters such as wave agitation, sea level fluctuation and bathymetric modification to produce four lithofacies comparable with the Llucmajor lithofacies: backreef lagoon, reef core, forereef slope and open shelf lithofacies.

By studying, through numerous sensitivity tests, the complex interplay between carbonate production and environmental changes, our results show that: 1) progradation of carbonate systems is strongly influenced by the interaction between the bathymetric profile of the basin and variation of carbonate production alongside accommodation; 2) increased production rate of rhodalgal sediments results in increased progradation of the platform, whereas reduced rhodalgal production rate results in the opposite response; and 3) platform geometry and internal architecture varies significantly according to the interaction of the predominant carbonate producing biotas, such as the production of rhodalgal sediments versus coral sediments.
Determining the vertical scale in videos of lava fountains from gravitational acceleration of single clasts at their zenith
Authors: Loisel Ariane , Llewellin Ed , Tisdale Caroline , Houghton Bruce
Published: March 2022

Videography is a popular tool for monitoring and characterising volcanic eruptions. Video records of lava fountaining episodes allow us to infer eruption parameters such as fountain heights, exit velocities, and pulse durations and frequencies, which may inform us on the subsurface processes that operate within the sub-volcanic plumbing system. However, the evolving shape and size of the natural features surrounding eruptive vent make it difficult to convert pixels in an image to meters in reality, due to the lack of fixed reference points with which to compare dimensions. Here we present a new method for determining the vertical scale in videos of lava fountains. We measure the vertical pixel-position of clasts near their zenith, over successive frames, and convert this to an acceleration. By assuming that the only force acting on single clasts near their zenith is gravity, we use the clast motion to determine the scale – mapping pixels to metres. Geometric considerations around the viewing angle and lens distortions are discussed and corrected for. We validate this method with laboratory experiments using water fountains and vertically projected light plastic balls, which act as analogues for lava fountains and single clasts, respectively. An example of field application is then provided from the 2018 fissure eruption at Kilauea (Hawaii, USA). This approach will be useful to physical volcanologists for monitoring the dynamics of eruptions that produce fountains and/or ballistics from video records, which are becoming increasingly available both from scientific teams and from a wider community of tourists and volcano-enthusiasts.
An ‘extinct’ transform fault hosts fluid flow and methane seepage – implications for understanding the role of transform faults in mid-ocean ridge fluid cycling 
Authors: Waghorn Kate , Argentino Claudio , Vadakkepuliyambatta Sunil , Bünz Stefan , Panieri Giuliana , Plaza-Faverola Andreia
Published: March 2022

The Svyatogor Ridge is the sedimented inside corner high of the Knipovich Ridge – Molloy Transform Fault intersection and despite its mid-ocean ridge system setting, it is host to a well-defined gas hydrate system. There is an extinct transform fault immediately south of the Svyatogor Ridge, which is partially sedimented. Our data suggests that there are distinct locations throughout the area which have elevated heat flow, usually coinciding with evidence of past or present fluid flow.

In particular, we show a site along the flank of the extinct transform fault which hosts a seep-like community associated with enhanced anaerobic methane oxidation in the shallow subsurface. While transform faults and fracture zones are important components of mid-ocean ridge systems, their role in fluid exchange between the lithosphere and hydrosphere remains unclear. High resolution seismic data from the inside corner high area at the Knipovich Ridge – Molloy Transform Fault intersection hints towards the important role the Molloy Transform Fault is playing in the fluid flow system in the area. However, integrated seismic, geochemical and heat flow datasets along the extinct transform fault clearly links the fault to elevated heat flow and fluid seepage, and to sites of gas hydrate accumulation. We posit that this site is a type of hybrid seep-vent style of fluid flow system.
Determining SEP Event Onset Times and Evaluating Their Uncertainty Using a Poisson CUSUM-Bootstrap Hybrid Method
Authors: Palmroos Christian , Dresing Nina , Gieseler Jan , Vainio Rami , Asvestari Eleanna
Published: March 2022

We are examining a new kind of hybrid method for finding SEP (Solar Energetic Particle) event onset times and assessing their uncertainties. Determining these onset times accurately is important because they are needed to relate the in-situ particle measurements to remote-sensing observations of the associated activity phenomena at the Sun. Only by this, can one identify the actual region and acceleration processes that generated the event. Different methods have been used to determine this onset time; however, the most common ones do not provide reasonable uncertainties so far. The method presented here employs a combination of a statistical quality control scheme, the Poisson-CUSUM (cumulative sum) method, and statistical bootstrapping for calculating a distribution of the necessary parameters for the Poisson-CUSUM method.

The CUSUM method is a statistical quality control scheme, used also in many industries, that is designed to give an early warning when the inspected process or variable changes (Page, 1954). Poisson-CUSUM refers to a specific cumulative sum method that assumes that the monitored variable has a Poisson distribution. 

By randomly choosing samples from the particle flux preceding the event, we acquire a distribution of different values for the estimated mean flux and for the standard deviation of the background measurements. These two distributions produce a set of possible onset times via the Poisson-CUSUM method, allowing us to evaluate the uncertainty of an onset time by the precision of our set of candidate onset times, and also to identify the most likely onset time. In addition, we apply the new method to energetic particle observations of the Solar Orbiter spacecraft that come with high energy and time resolution, and perform velocity dispersion analyses. 

 

S. PAGE, CONTINUOUS INSPECTION SCHEMES, Biometrika, Volume 41, Issue 1-2, June 1954, Pages 100–115, https://doi.org/10.1093/biomet/41.1-2.100
Comparative study of two Mediterranean pine forests demonstrates a dominant effects of soil moisture supply over atmospheric VPD in influencing gross primary productivity
Authors: Markos Nikos , Preisler Yakir , Radoglou Kalliopi , Rotenberg Eyal , Yakir Dan
Published: March 2022

Forest grown in semi-arid regions are facing severe drought limitations, nevertheless they are still a considerable component of the global carbon cycle. Drought limitations on ecosystem carbon fluxes can be caused either by limited soil moisture supply, mainly expressed through the soil water content (SWC), or enhanced atmospheric demand, expressed through the atmospheric VPD. However, these two parameters are generally strongly correlated and the distinguish of their differential effects on ecosystem level processes is difficult. While soil water content is mainly affected by the local precipitation patterns, VPD is strongly affected by the air temperature. Both quantities are expected to alter under the current climate change scenarios, but the rise in temperature is expected to result in amplified increased in VPD. The ability to quantify the differential effects of SWC and VPD on ecosystem productivity is, therefore, critical for making predictions about future forest productivity and survival in the Mediterranean region under the ongoing climate change.

In this study we attempt to make a distinction between the impact of soil moisture and VPD on water limitations on GPP in Aleppo pine forests in Greece and in Israel. For the aim of the study, we performed GPP estimates for two Mediterranean sites in the two study sites that differ in water supply and local VPD. The separation of SWC and VPD limitations was achieved by the use of generalized additive models. Our results indicate that the parameter that dominates drought limitations in Aleppo pine is SWC, while VPD has a secondary and lesser effect.

Aleppo pine is a conifer species representing one of the major components of Mediterranean ecosystems, which is, in turn, one of the most vulnerable regions to climate change. The results imply, therefore, that the potentially enhanced increase in VPD, caused by rising temperatures in these regions, is likely to have a limited effect on future carbon fluxes, which will depend more strongly on trends in precipitation pattern.
EnVAR Quality Control and Observation Aggregation for ICON-LAM
Authors: Burba Mareike , Hollborn Stefanie , Ulbrich Sven , Schraff Christoph , Anlauf Harald , Potthast Roland , Knippertz Peter
Published: March 2022

The German Weather Service (DWD) operationally runs an LETKF (Localized Ensemble Kalman Filter) assimilation scheme for the regional weather forecasts with the ICON-LAM (ICON Limited Area Mode) Numerical Weather Prediction model. We investigate the potential of using an EnVAR (Ensemble Variational data assimilation) using the kilometre-scale Ensemble Data Assimilation (KENDA) ensemble. Quality Control (QC) and Observation Aggregation (OA) are essential parts of a data assimilation system. The former ensures that the assimilated observations are likely to be "acceptable", in the sense of technical, physical and statistical properties. The latter reduces the amount of data and computations under the aspect of efficiency, and helps handling redundant or correlated observations.

We show results of assimilation experiments for KENDA and EnVAR using a similar selection of conventional observations after QC and OA, while using a fully dynamic B matrix and no variational QC. The difference of the results of the two algorithms does not only depend on the partially differing implementation of QC and OA, but also due to partially different implementations of the observation operators or even the supported observation types. Important differences to the operational global EnVAR code are e.g. the choice of suitable observation types and the interpolation specification of the first guess to the locations of the observations.

As we use the same code for the EnVAR as in the DWD's global data assimilation scheme, we can potentially assimilate many other observations systems beyond conventional observations. This includes, after some adaptations, a wide range of spaceborne observations. Additionally, it is possible to run a regional EnVAR assimilation and a deterministic forecast with a coarse resolution first guess ensemble. Re-using existing ensembles for the ensemble B matrix might be a computationally efficient way to use a variational algorithm for deterministic forecasts.
Spatiotemporal migration patterns of rivers across the Himalayan foreland basin
Authors: Deshpande Rucha Sanjay , Mandal Sanjay Kumar
Published: March 2022

Rivers are one of the most dynamic features on the Earth's surface. Over time, river channels migrate across its floodplain either gradually or rapidly in response to erosion, accretion, sediment transport, or high-water flow events, respectively. These lateral migrations of the river channel could be detrimental to the human settlements, infrastructure, and ecological elements in the floodplain region. Indo-Gangetic plain is the world's largest alluvial tract, drained by rivers such as Ganga, Brahmaputra, Indus, and their tributaries. Most of these rivers are known to be very dynamic and have the potential of affecting a large population. Previous studies focused on individual rivers to understand the spatiotemporal patterns of channel migration. However, regional-scale analysis becomes necessary to understand the large-scale controls on river dynamics and determine their response to future climate change and anthropogenic activities. This study intends to map and measure migration rates of all the major river channels in the Himalayan foreland basin using Landsat imagery from 1990 to 2020. We generated annual active channel binary masks from Landsat imagery using Google Earth Engine. We delineated the centerline of channels and calculated channel migration rates between consecutive years using the RivMAP toolbox in MATLAB. Here we show that the elevation difference between the river channel and its floodplain acts as a spatial constraint and controls the relationship between channel patterns and migration rates. Channel segments with higher elevation differences correspond to less channel movement and vice versa. Additionally, we explore the effects of anthropogenic activities on river dynamics in the study area.
The Trilogy of Ocean, Climate and Coast: The Urgency and Exigency of Literacy
Authors: Crookall David , Promduangsri Pariphat , Promduangsri Pimnutcha
Published: March 2022

Over the last decade, the use of simulation, games and role-play have been gaining ground in ocean and climate literacy.  This session will describe and outline results from a particularly powerful, but underused, form of experiential learning format, called participatory simulation (PS).  It contains (elements of) game, simulation, role-play, experience, human interaction, decision-making, negotiation, stakeholder engagement, etc.  It is often large scale, open ended, goal and results oriented, free form and data driven.  Debriefing is a crucial component.

It is difficult to separate climate and ocean.  Without the ocean, the Earth would be an unliveable hothouse.  Without climate the ocean would hardly exist.  Our overarching goal, therefore, was to help participants understand the oceans-climate nexus and to become better ocean-climate-literate stakeholders.  The Inter- Oceans-Climate School (IOCS), France, has run two sessions so far (the last was three and a half days spread over three weeks, and the results are encouraging).  In our previous sessions, we welcomed participants from Latin America, Africa, the Middle East, India and Europe.  The IOCS is an official event of the Intergovernmental Oceanographic Commission (IOC) of UNESCO, as part of the UN Decade of Ocean Science for Sustainable Development.

Our presentation will describe the event and analyse results obtained from detailed feedback by participants.  Co-authors include both organizers and participants.  We will endeavour to answer your questions and entice you to participate in an upcoming session.
Evidence of seasonal modulation of seismic sequences in the Azores 
Authors: Lordi Dias Ana Laura , Neves Maria C. , Custódio Susana , Dumont Stephanie
Published: March 2022

This work provides an assessment of cyclical variations in seismicity and their relationship with hydrological disturbances in the Azores Triple Junction, looking in particular for seasonal and inter-annual modulations of the earthquake occurrence rate caused by sea-level anomaly and total wave height variations. The work involves the manipulation and the statistical analysis of the Azores seismic catalogue (considering only oceanic events), from 2008 to 2018. We analyzed the seasonal variations of the ocean seismicity by computing the ratio of Winter/Spring (JFMA) events and Summer/Fall (JASO) events, following demonstrated methodologies applied in previous studies in continental areas such as the New Madrid seismic zone and the Himalayan mountains. The seismicity rates in the Azores are higher during Summer/fall (JASO) and lower during Winter/Spring (JFMA), with a ratio JFMA/JASO significantly lower than 1. Different months were also considered for the Winter/Summer ratio (NDJF/MJJA) to observe if the seasonal pattern is still present and statistically significant. The results show that the seasonal variations are better captured when considering the NDJF/MJJA ratio and regions with higher number of events, such as between the Mid-Atlantic Ridge and Faial and Pico islands. Monte Carlo simulations and the Jack-knife approach confirmed that the probability of observing such a seasonality by chance is less than 1% mainly for magnitudes from M3.2 to M5.0, and is not the consequence of extreme deviations. The connection between the seasonal modulation and the hydrological loads was investigated using the Singular Spectrum Analysis. The principal components of the ocean seismicity rate present a strong correlation with the total wave height, and mainly with the sea-level anomaly, which might be possible triggers of the ocean seismicity rate in the Azores region. The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL. This is a contribution to the RESTLESS project PTDC/CTA-GEF/6674/2020.
A discontinuous Galerkin method for sequences of earthquakes and aseismic slip on multiple faults using unstructured curvilinear grids
Authors: May Dave , Uphoff Carsten , Gabriel Alice-Agnes
Published: March 2022

Simulations of sequences of earthquakes and aseismic slip (SEAS) including more than one fault, complex geometries and elastic heterogeneities are challenging. We present a symmetric interior penalty discontinuous Galerkin (SIPG) method accounting for the complex geometries and heterogeneity of the subsurface. The method accommodates two- and three-dimensional domains, is of arbitrary order, handles sub-element variations in material properties and supports isoparametric elements, i.e. high-order representations of the exterior and interior boundaries and interfaces including intersecting faults.

We provide an open-source reference implementation, Tandem, that utilises highly efficient kernels, is inherently parallel and well suited to perform high resolution simulations on large scale distributed memory architectures. Further flexibility is provided by optionally defining the displacement evaluation via a discrete Green's function, using algorithmically optimal and scalable sparse parallel solvers and preconditioners. We highlight the characteristics of the SIPG formulation via an extensive suite of verification problems (analytic, manufactured and code comparison) for elasto-static and seismic cycle problems. We demonstrate that high-order convergence of the discrete solution can be achieved in space and time for elasto-static and SEAS problems.

Lastly, we apply the method to realistic demonstration models consisting of a 2D SEAS multi-fault scenario on a shallowly-dipping normal fault with four curved splay faults, and a 3D multi-fault scenario of instantaneous displacement due to the 2019 Ridgecrest, CA, earthquake sequence. We exploit the curvilinear geometry representation in both application examples and elucidate the importance of accurate stresses (or displacement gradients) representations on-fault. Our results exploit advantages of both the boundary integral and volumetric methods and is an interesting avenue to pursue in the future for extreme scale 3D SEAS simulations.
Synergizing earth observations and seasonal forecasts within an innovative climate index: the case of forage production in Italy 
Authors: Dal Gesso Sara , Venturini Marco , Petitta Marcello
Published: March 2022

In the agriculture sector, climate-related economic losses have reached an average of €73 bn a year worldwide. It is, hence, of utmost importance to act now to build a climate-resilient agricultural system by forecasting the future climate risk and implementing adaptation actions. Agriculture insurance plays a crucial role in promoting the resilience of the agricultural sector to external shocks, as it covers the production and financial risks of farmers, and related shortfall risks of interconnected stakeholders throughout the food chain. For a climate-proof agriculture, the insurance industry needs to evolve. Offering traditional coverage is becoming insufficient, with climate change unfolding its impact on the severity and frequency of extreme events.

We present a climate service for monitoring and forecasting the climate risk on crop and livestock production tailored to the needs of insurers providing agricultural coverage. The climate service has been developed and validated within the ESA-funded project TERRA - climaTe sERvices for a Resilient Agriculture, thanks to the engagement of key stakeholders in the whole value chain. The service is a risk assessment and monitoring tool based on a climate-enhanced vulnerability index. Such an index seamlessly integrates satellite data, reanalysis products and seasonal forecasts. In particular, it combines the level-2 variables from sentinel 1, 2 and 3, available through the Copernicus Global Land Service, in a unified vulnerability index, that is integrated with the reanalysis products and seasonal forecasts available through the Climate Data Store of the Copernicus Climate Change Service. The climate-enhanced vulnerability index is applied to the specific case of forage production in Italy.
Contribution of local examples of co-evolution of society and hydrology to address current and future challenges of sustainability in the context of the Panta Rhei Book
Authors: Polo María José , Castro Cynthia , Penny Gopal , Gunda Thusdara , Montanari Alberto
Published: March 2022

Impacts and trade-offs between society and hydrological processes cover a wide range of issues, for which climate, geography, environment, cultural context, economy, and society altogether result in largely different coevolution schemes and current scenarios. This work presents a selection of case studies addressing the Panta Rhei Decade’s goals and discussions, that cover representative examples to assess future challenges of sociohydrology to be included in the Panta Rhei Book results. As a follow-up of the work progress presented in previous conferences, we focus now on each storyline to highlight their contribution to the Panta Rhei decade’s work and impact on future reflections, and pathways.

Specifically, some similarities and major divergences are assessed between local cases across geography and topics in a preliminary attempt to identify the key conclusions of this paradigm and the most relevant sectors dealing with socio-hydrological processes now, and in the future. These results pave the line towards the final lessons learnt from this process, to be presented in the XXIst Scientific Assembly of the IAHS.
Evaluation of the AQG-A02 and AQG-B02 absolute quantum gravimeter accuracy
Authors: Glässel Julian , Reich Marvin , Güntner Andreas , Wziontek Hartmut , Falk Reinhard , Rülke Axel
Published: March 2022

Quantum gravimeters measure absolute gravity by the matter-wave interference of ultracold atoms. This poses a promising new alternative technology to the established falling corner cube gravimeters, such as the FG5/X, which currently provide the reference for absolute terrestrial gravimetry. Due to the lack of mechanical components, quantum gravimeters offer advantages in maintenance and allow for continuous operation over extended time periods. Moreover, the fundamental difference in measurement principle could reveal potentially unknown systematic biases in either system.

The iXblue Absolute Quantum Gravimeter (AQG) is the first commercially available instrument of this kind. As one of the early users, BKG and GFZ are evaluating the AQG-A02 and AQG-B02 for performance and future application in routine operations. In autumn 2021, both instruments have for the first time taken part in a comparison, the international comparison of absolute gravimeters WET-CAG2021 at the Geodetic Observatory Wettzell, Germany. Here we present current results based on these measurements, regarding the AQG’s absolute accuracy. Further, we evaluate signal stability from a long-term measurement over 6 weeks.