bluuebunny/crossref_metadata_2025 huggingface dataset:
Peak water in observed glacier-fed streamflow time series
Authors: Stahl Kerstin , van Tiel Marit , Moore R. Dan
Published: March 2021

Glacier peak water describes the initial increasing and subsequent decreasing trend of glacier melt water as a response to global warming. The phenomenon might encourage excessive water use that cannot be sustained in the long-term. Knowing magnitude and time scale of its effect on streamflow trends and changes in partly glacierized catchments is therefore needed. This comparative regional study examined August streamflow records from 1976-2015 in the European Alps, Norway, Western Canada, and Alaska. It aimed to detect whether and when a peak was reached or passed and how strong decreasing post-peak streamflow trends were. A one-peak hypothesis could not be confirmed in many of the records and the variability of individual series' detected peaks and trends is large. Some common patterns in the timing of peaks and general trend directions in the records could be generalized. These suggest: a peak early in the period in Western Canada followed by mostly declining streamflow trends, pre-peak conditions in Alaska resulting in mostly positive streamflow trends, variable peaks in Norway and the Alps from the mid-1990s on with differences for low and highly glacierized catchments. Trends and peaks in climate-variability corrected August streamflow broadly related to phases of regional glacier retreat, but local variability is more complex.  Only weak systematic deviations were found related to catchment characteristics. This multi-record and multi-region comparison of streamflow observations suggests that knowledge on a regional phenomenon will need to be complemented with local monitoring and modelling to provide useful information for water resources planning.
ENSO teleconnections in an ensemble of CORDEX-CORE regional simulations
Authors: Torres-Alavez Abraham , Kucharski Fred , Coppola Erika , Castro Lorena
Published: March 2021

Using high-spatial-resolution regional simulations from the global program, Coordinated Regional Climate Downscaling Experiment-Coordinated Output for Regional Evaluations (CORDEX-CORE), we examine the capability of regional climate models (RCMs) to represent the El Niño–Southern Oscillation (ENSO) precipitation and surface air temperature teleconnections during boreal winter (December-February). This study uses CORDEX-CORE simulations for the period 1975-2004 with two RCMs, the RegCM4 and REMO, driven by three General Circulation Models (GCMs) from phase 5 of the Coupled Model Inter-comparison Project (CMIP5). The RCM simulations were run at a 25-km grid spacing over Africa, Central and North America, South Asia and South America.

The teleconnection patterns are calculated in the reanalysis data (observations), and these results are compared to those of the ensemble and individual simulations of both the GCM and RCM. Linear regression is used to calculate the teleconnection patterns and a permutation test is applied to calculate the statistical significance of the regression coefficients. Results show that overall, the ENSO signal from the GCMs is preserved in the ensemble and the individual RCM simulations over most of the regions analyzed. These reproduced most of the observed regional responses to ENSO forcing and showing teleconnection signals statistically significant at the 95% level. Furthermore, in some cases, the ensemble and individual simulations of RCMs improve the spatial pattern and the amplitude of the ENSO precipitation response of the GCMs, particularly over southern Africa, the Arabian-Asian region, and the region composed of Mexico and the southern United States. These results show the potential value of the GCM-RCM downscaling systems not only in the context of climate change research but also for seasonal to annual prediction.
Sedimentary signature of past West Antarctic Ice Sheet and ocean dynamics from deep sea drill cores in the Amundsen Sea (IODP Expedition 379)
Authors: Robinson Delaney E. , Wellner Julia S. , Gohl Karsten , Reinardy Benedict T.I. ,   IODP Expedition 379 Scientists
Published: March 2021

Modern observations of the West Antarctic Ice Sheet (WAIS) show relatively warm ocean water causing negative changes in ice-sheet mass. The largest ice mass loss in the WAIS occurs in the Amundsen Sea region, where warm water flows onto the shelf and melts the marine-based ice shelves, a process with the potential to lead to full collapse of the WAIS. Geologic records from similar and warmer climate conditions than today are required to understand the role of changes affecting the Amundsen Sea drainage sector in steering past WAIS dynamics. International Ocean Discovery Program (IODP) Expedition 379 successfully recovered sediment drill cores from two sites on the continental rise in the Amundsen Sea, West Antarctica. Both sites are located on a large sediment drift that provides a continuous, long-term record of glacial history in a drainage basin that is fed exclusively by the WAIS. Sediments at both sites are associated with depositional processes related to glacial extent on the shelf. Repeated alternations of two major facies groups composed of dark-gray laminated silty clay and massive/bioturbated greenish-gray, clast-bearing mud are interpreted to represent cycles of glacial and interglacial periods. High-resolution sedimentological analyses define characteristics that vary within the two broad sedimentary facies, helping provide constraints on depositional processes of the sediments and controlling WAIS dynamics.

Detailed investigations were conducted on Miocene to Pliocene strata using grain size and shape analysis, combined with X-Ray Fluorescence data and computer tomography scans, as well as detailed thin section analysis. Laminated silty clay intervals contain consistently fine-grained sediments dominated by terrigenous components that were supplied by downslope transport during glacial periods. Massive/bioturbated muds with ice rafted debris (IRD) display variable grain size trends accompanied by changes in particular elemental ratios indicating increased supply of biogenic components and possibly reduced delivery of terrigenous detritus during interglacial periods. The boundaries between massive, interglacial facies and laminated, glacial facies are usually sharp; although occasionally, a more gradual interglacial-glacial transition is observed. Different sedimentation patterns suggest fluctuations in downslope transport and bottom current intensities that are connected to ice sheet extent on the West Antarctic continental shelf. Further analysis may reveal facies characteristics that vary with glacial-interglacial cycles and allow improved interpretation of past WAIS dynamics and Southern Ocean circulation.
Hydromulches as a possible alternative to herbicides in organic woody crops.
Authors: Moreno Valencia Marta María , Villena Jaime , González-Mora Sara , Atance Concepción , Ortega Carlos , Ruiz-Orejón Antonio , Campos Juan A. , Moreno Carmen
Published: March 2021

One of the main problems associated to woody crops is the weed control. This activity is mainly done by the application of herbicides and repetitive tillage, with the consequent environmental problems in the first case and the progressive soil erosion and fuel fossil consumption in the second one. Plastic mulches, mainly composed of polyethylene, are also used for this purpose, but they are mostly employed in vegetable crops. Additionally, weed control is especially complicated in young woody crops, which are very sensitive to phytotoxicities derived from herbicides and the use of machinery can damage the tree trunks, and also in established plantations, mainly in intensively managed orchards. Besides, all these problems are especially pronounced in organic farming, where the use of chemical herbicides are not allowed.

For this purpose, three mixtures based on by-products derived from the agricultural sector, mixed with a binder and recycled paper paste and applied in liquid form on the ground with subsequent solidification (hydromulch) were evaluated, focused on the effect on weed control in an intensive almond crop and in young olive trees grown in big containers. Controls included manual weeding and no-weeding treatments.

In summary, and a basis for future tests, hydromulches exerted an acceptable weed control, although weeds can emerge through cracks in continuous formation, and especially when the material is softened by water. These preliminary results position hydromulches as an interesting alternative to herbicides and the conventional machinery and plastic mulches widely used.

Keywords: hydromulches, weed control, organic farming.

Acknowledgements: Project RTA2015-00047-C05-03 - INIA (Spanish Ministry of Economy and Competitiveness).
The Glacial Geomorphology of central-Patagonia (44 – 46°S): glacier dynamics within and beyond the austral Andes
Authors: Cooper Emma-Louise , Thorndycraft Varyl , Davies Bethan , Palmer Adrian , García Juan-Luis
Published: March 2021

The former Patagonian Ice Sheet (PIS, 38 – 56°S) was one of the largest ice masses to develop in the Southern Hemisphere. Its formation was uniquely influenced by the Southern Westerly Winds (SWWs) colliding with the Andean Cordillera, generating a marked West-East precipitation gradient. Variability in the strength and position of the SWWs is thought to have played a significant role in ice sheet dynamics. In particular, understanding of the timing of palaeo-glacier fluctuations is required to elucidate the role of these regional climate drivers on ice retreat. However, in order to fully understand the structure and pace of deglacial ice fluctuations, detailed glacial geomorphological reconstructions must be completed.

During deglaciation, as the PIS retreated from local Last Glacial Maxima positions, large proglacial lakes formed east of the austral Andes, ice-dammed by the Andean Cordillera. In central-Patagonia (44 – 46°S) during the final stages of deglaciation, these ice-dammed lakes drained to the west, through the Andean Cordillera, opening new drainage corridors towards the Pacific Ocean. As a result, the floors of these valleys are now exposed subaerially, preserving a complex suite of glacial and glaciolacustrine landform assemblages. Moreover, as most of the region is now ice-free, excluding smaller mountain ice caps such as Queulat (44.4°S, ~2000 m a.s.l) more recent Holocene geomorphology has also been exposed. These landforms possess the potential to yield new insights into the style and manner of regional ice retreat, during the transition from large terrestrial ice-lobes, to smaller mountain glaciers and ice caps.

We mapped seven terrestrial palaeo-ice lobes of the PIS: the Río Pico (~44.2°S), Río Cisnes (~44.6°S), Lago Plata-Fontana (~44.8°S), Río El Toqui (~45°S), Lago Coyt/Río Ñirehuao (~45.3°S), Simpson/Paso Coyhaique (~45.5°S) and Balmaceda (~46°S) lobes. Mapping was then extended west, into the Andean Cordillera. Landforms were mapped using ESRI™ DigitalGlobe World (1-2 m) and Sentinel-2 (10 m) imagery, verified with field surveys. These new data build on previous work in the area. To date, over 60,000 ice-marginal, ice-contact, subglacial, glaciolacustrine and glaciofluvial landforms have been mapped across a ~70,000km2 area of the Andean Cordillera and adjacent valleys. When combined with robust geochronological reconstructions, these data possess the potential to inform on the role of the SWWs, versus local topography, and ice-marginal processes in regulating the structure and rate of regional deglaciation.
Greek National Map of Soil Organic Carbon
Authors: Triantakonstantis Dimitris , Detsikas Spyros
Published: March 2021

Soil organic carbon (SOC) is the carbon that remains in the soil after the partial decomposition of any material produced by living organisms. It is an essential parameter for agricultural production, the potential sequestration of CO₂ in soil and a vital soil function for global carbon cycle. However, a vast potential of soil carbon is removed from agricultural soils due to non-sustainable soil management practices. Mapping SOC and its changes over time and space is highly valuable for estimating the CO₂ emissions and effects of climate change to the environment. In the present work, the Greek National Map of SOC is presented calculating the SOC stock in 30 arc-seconds spatial resolution using the Global Soil Partnership and Food and Agriculture Organization of the United Nations (FAO) guidelines for SOC mapping. The presented methodology considers the reference framework of the SCORPAN model for digital soil mapping, which can predict SOC stocks in correspondence with soil forming factors. Among the key variables used for estimating SOC stocks are environmental covariates such as climate and meteorological data, thematic maps, digital terrain data, geomorphometry and soil data. Data mining and geostatistical techniques (random forests, support vector machines, regression-kriging) are used to estimate the SOC stocks. Internal and external map accuracy is used to evaluate the performance of the Greek National SOC map. Accuracy of FAO’s methodology was examined herein using different modelling approaches. As indicated in the results, the most accurate map was produced by the random forest technique and an accuracy of FAC2=0.968, RMSE=0.322 and r=0.756. The main findings are also discussed herein covering aspects relevant to the method implementation, validation and feasibility of operational implementation.

Keywords: soil organic carbon, climate change, soil management practices, Greek National Map
Monitoring Arctic and high-latitude wildfires in 2019 and 2020
Authors: Parrington Mark , McCarty Jessica , Smith Thomas , Turetsky Merritt , Di Giuseppe Francesca , Vitolo Claudia , Garrigues Sebastien , Ades Melanie , Agusti-Panareda Anna , Barre Jerome , Engelen Richard , Flemming Johannes , Inness Antje , Kipling Zak , Peuch Vincent-Henri , Wooster Martin , Zhang Tianran , De Jong Mark , Vamborg Freja
Published: March 2021

The boreal summers of 2019 and 2020 were witness to extensive high northern latitude wildfire activity, most notably within the Arctic Circle across eastern Russia. Near-real-time monitoring of the wildfire activity, based on satellite observations of active fires, showed widespread and persistent fires at a scale that had not been observed in the previous years that satellite observations are available. The European Centre for Medium-Range Weather Forecasts (ECMWF) through its operation of, and contribution to, different Copernicus Services is in a unique position to provide detailed information to monitor high-latitude wildfire activity, including their evolution and potential impacts, when they occur. Fire weather forecasts from the Copernicus Emergency Management Service (CEMS), and surface climate anomalies from the Copernicus Climate Change Service (C3S) both provide context to the environmental conditions required for wildfires to persist. Analyses based on observations of fire radiative power, along with analyses and forecasts of associated atmospheric pollutants, from the Copernicus Atmosphere Monitoring Service (CAMS) aid in quantifying the scale and intensity in near-real-time and the subsequent atmospheric impacts. We present an analysis of Arctic and high northern latitude wildfires during the summers of 2019 and 2020, reviewing the underlying meteorological/climatological conditions, the estimated emissions and transport of smoke constituents over the Arctic Ocean. We will show that the different datasets, while being relatively independent, show a strong correspondence and provide a wealth of information required to monitor and provide context for wildfire activity.
Earthquake ruptures tied to long-lived plate interface deformation 
Authors: Cubas Nadaya , Agard Philippe , Tissandier Roxane
Published: March 2021

Predicting the spatial extent of mega-earthquakes is an essential ingredient of earthquake hazard assessment. In subduction zones, this prediction mostly relies on geodetic observations of interseismic coupling. However, such models face spatial resolution issues and are of little help to predict full or partial ruptures of highly locked patches. Coupling models are interpreted in the framework of the rate-and-state friction laws. However, these models are too idealized to take into account the effects of a geometrically or rheologically complex plate interface. In this study, we show, from the critical taper theory and a mechanical analysis of the topography, that all recent mega-earthquakes of the Chilean subduction zone are surrounded by distributed interplate deformation emanating from either underplating or basal erosion. This long-lived plate interface deformation builds up stresses ultimately leading to earthquake nucleation. Earthquakes then propagate along a relatively smooth surface and are stopped by segments of heterogeneously distributed deformation. Our results are consistent with long-term features of the subduction margin, with observed short-term deformation as well as physical parameters of recovered subducted fragments. They also provide an explanation for the apparent mechanical segmentation of the megathrust, reconciling many seemingly contradictory observations on the short- and long-term deformation. Consequently, we propose that earthquake segmentation relates to the distribution of deformation along the plate interface and that slip deficit patterns reflect the along-dip and along-strike distribution of the plate interface deformation. Topography would therefore mirror plate interface deformation and could serve to improve earthquake rupture prediction.
Remote Sensing and Citizen science supporting irrigation monitoring in the Capitanata Irrigation Consortium (Italy)
Authors: Corbari Chiara , Paciolla Nicola , Ben Charfi Imen , Woods Mel
Published: March 2021

In different ways, Citizen Science and Remote Sensing (RS) have been recently developing as innovative and inclusive ways to improve data gathering and the comprehension of many environmental biophysical processes. In this framework, the GROW Observatory has been promoting the individual farmer awareness in agriculture as a counterpart to the ever-developing frequency and accuracy of RS products.

In this analysis, 456 on-ground sensors from the GROW Observatory have been deployed in the Capitanata Irrigation Consortium (Apulia, Italy), with the aim of measuring the components of the water cycle with a dense, high-resolution pattern. The possibility of channelling these data into a high-resolution, plant-oriented Irrigation Water Need (IWN) parameter has been investigated, as a counterpart of coarser-resolution, spatially distributed monitoring powered by remote sensing and hydrological modelling.

The instruments have the possibility of measuring three main variables: Surface Soil Moisture (at a maximum depth of 5 cm), Air temperature and Solar Illuminance (measured a few centimetres above ground). The monitoring period is July-October 2019, contemplating a wide range of different cultivation regimes.

Irrigation water needs estimates has been obtained both in a point-wise (plant-oriented) and field-wise (spatial) format, in order to derive an irrigation water management tool. IWN and Surface Soil Moisture data are also employed in inferring back actual irrigation information from on-ground and RS data. These estimates have then be compared with observed data.

Intermediate measure of Surface Soil Moisture, Air Temperature and radiation (by the Solar Illuminance proxy) have also been compared both with local measurements (those of and eddy-covariance station in place) and RS products from Sentinel and Landsat. Furthermore, Solar Illuminance data have been processed to extract a Leaf Area Index (LAI) product, also comparable with satellite estimates. These comparisons have been conducted through spatial and temporal correlations between the ground-gathered and remotely-sensed data.

The potentiality and also the limitations of these low-cost instruments are presented and discussed.
Multiple-point geostatistical reconstruction of GPR reflection data
Authors: Zhang Chongmin , Gravey Mathieu , Irving James , Mariethoz Gregoire
Published: March 2021

A common challenge in reflection GPR data processing and analysis is the reconstruction of missing traces. Gap filling, for example, may be needed to fill-in data where they could not be recorded in the field in order to produce a uniform trace spacing that is important for Fourier- or finite-difference-based migration methods. Similarly, field GPR data recorded in continuous mode with an uneven trace spacing are usually needed at a regular spacing for subsequent visualization and imaging. Finally, we may wish to increase the spatial resolution of a GPR dataset through “super-resolution”, whereby new traces are simulated between the existing ones in order to improve the interpretability of the data. A common challenge in these various applications is the need to interpolate a variable that has a complex, non-smooth behavior.

A number of interpolation methods have been proposed for filling in missing GPR traces over the past decades. The majority of these, however, tend to produce overly smooth and unrealistic results. Here, we present a data reconstruction strategy based on the QuickSampling (QS) multiple-point geostatistical method. With this approach, GPR traces are simulated via sequential conditional simulation based on patterns that are observed in nearby high-resolution data (training images). To evaluate the potential of our approach, we apply it to a variety of field 2D GPR datasets. Results indicate that the QS method provides an effective means of simulating missing GPR traces in a highly realistic manner.
Estimating rice water requirements in the Lis Valley (Portugal) using remote sensing platforms: preliminary results for the 2020 cultivation season
Authors: G. Jorge Romeu , P. de Lima Isabel , L.M.P. de Lima João
Published: March 2021

In irrigated agricultural areas, where the availability of water for irrigation does not rely on any water storage, water management requires special attention, in particular under large annual and inter-annual variability in the hydrological regime and the uncertainty of climate change. The inherent increased vulnerability of the agro-ecosystem, makes the monitoring of crop conditions and water requirements a valuable tool for improving water use efficiency and, therefore, crop yields.

This presentation focus on one such agricultural area, located in the Lis Valley (Centre of Portugal), which is a rather vulnerable area also facing drainage and salinity problems. The study aims at contributing to better characterizing the temporal and spatial distribution of rice water requirements during the growing season. Irrigation water sources are the Lis River and its tributaries, which discharges depend directly from precipitation. The most important problems of water distribution in the Lis Valley irrigation district are water shortage and poor water quality in the dry summer period, aggravated by limitations of the irrigation and drainage systems that date back to the end of the 1950’s.

We report preliminary results on using remote sensing data to better understand rice cropping local conditions, obtained within project GO Lis (PDR2020-101-030913) and project MEDWATERICE (PRIMA/0006/2018). Rice irrigation is traditionally conducted applying continuous flooding, which requires much more irrigation water than non-ponded crops, and therefore needs special attention. In particular, data obtained from satellite Sentinel-2A land surface imagery are compared with data obtained using an unmanned aerial vehicle (UAV). Data for rice cultivated areas during the 2020 cultivation season, together with weather and crop parameters, are used to calculate biophysical indicators and indices of water stress in the vegetation. Actual crop evapotranspiration was appraised with remote sensing based estimates of the crop coefficient (Kc) and used to assess rice water requirements. Procedures and methodologies to estimate Kc were tested, namely those based on vegetation indices such as the Normalized Difference Vegetation Index (NDVI). Results are discussed bearing in mind the usefulness of the diverse tools, based on different resolution data (Sentinel-2A and UAV), for improving the understanding of the impacts of irrigation practices on crop yield and main challenges of rice production and water management in the Lis Valley irrigation district.
Improving nowcasting and forecasting of the Sun-to-Belts space weather chain through the H2020 SafeSpace project
Authors: Daglis Ioannis A. , Bourdarie Sebastien , Cueto Rodriguez Juan , Darrouzet Fabien , Lavraud Benoit , Poedts Stefaan , Sandberg Ingmar , Santolik Ondrej ,   SafeSpace Team
Published: March 2021

The H2020 SafeSpace project aims at advancing space weather nowcasting and forecasting capabilities and, ultimately, at contributing to the safety of space assets. This will be achieved through the synergy of five well-established space weather models covering the complete Sun – interplanetary space – Earth’s magnetosphere – radiation belts chain. The combined use of these models will enable the delivery of a sophisticated model of the Van Allen electron belt and of a prototype space weather service of tailored particle radiation indicators. Moreover, it will enable forecast capabilities with a target lead time of 2 to 4 days, which is a tremendous advance from current forecasts that are limited to lead times of a few hours. SafeSpace will improve radiation belt modelling through the incorporation into the Salammbô model of magnetospheric processes and parameters of critical importance to radiation belt dynamics. Furthermore, solar and interplanetary conditions will be used as initial conditions to drive the advanced radiation belt model and to provide the link to the solar origin and the interplanetary drivers of space weather. This approach will culminate in a prototype early warning system for detrimental space weather events, which will include indicators of particle radiation of use to space industry and spacecraft operators. Indicator values will be generated by the advanced radiation belt model and the performance of the prototype service will be evaluated in collaboration with space industry stakeholders. The work leading to this paper has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870437 for the SafeSpace (Radiation Belt Environmental Indicators for the Safety of Space Assets) project.
Statistical Analysis of Madden-Julian Events Using Time Series Indices.
Authors: Minjares Mónica , Barreiro Marcelo , Corral Álvaro
Published: March 2021

The Madden-Julian Oscillation (MJO) is the dominant mode in the tropical atmosphere on sub-seasonal time scales, with a strong influence on the tropical weather and impacts on higher latitudes. Although it is an in depth-studied phenomenon, its intensification and attenuation mechanisms are not fully understood. The purpose of this communication is to analyse the statistics of MJO events using the Wheeler and Hendon index.
In our framework an MJO event takes place when the amplitude of the index is above a threshold for a certain number of days, depending on the averaging of the signal. With this, we define the maximum amplitude of an event, its duration and its size which is the sum of the amplitudes along the duration of an event.
We then analyse how the statistical properties change under variations in the definition of events. We further explore whether the tails of the event distributions are heavy tailed. As MJO interacts with other phenomena and has impacts on higher latitudes we compare the statistics of the MJO with other atmospheric indices. These statistical analyses may contribute to the knowledge of the intensification and attenuation processes that constitute the basic dynamics of the MJO.
Towards a better understanding of the role of glacier retreat and permafrost degradation in triggering secondary lahars
Authors: Frimberger Theresa , Andrade Daniel , Krautblatter Michael
Published: March 2021

As everywhere in the Andes, tropical glaciers have been rapidly retreating since several decades. The glaciers of Cotopaxi volcano, Ecuador, have been reduced in area by about 50% since 1976 (Cáceres, 2017). The Cotopaxi is mostly famous for its capacity to produce massive lahars during volcanic eruptions, but comparably smaller, secondary lahars generated in post-eruptive periods by heavy rainfall occur more frequently on the volcano’s flanks. However, since a few years, secondary lahars that originate in proglacial areas without any clear trigger mechanism are recorded at Cotopaxi. This raises the question of whether there exists a process-based link between the occurrence of secondary lahars and the retreat of cold-based glaciers with accompanied permafrost degradation in the former subglacial frozen pyroclastic material over the following years and decades.

Here, we present the data obtained from laboratory-calibrated Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) conducted near the glacier margin between 5000 and 5300 m asl, which provide a better understanding of frozen/unfrozen conditions and the structure of the subsurface. In addition, data loggers have been recording surface air temperatures close to the glacier since May 2018. Our measurements show that permafrost cannot develop under current thermal conditions, but high electrical resistivities at depths of 10-20 m correspond to calibrated rock temperatures below 0 °C. The detected frozen lenses may act as detachment planes of periglacial secondary lahars in pyroclastic material recently exposed by glacier retreat.

 

Cáceres, B. (2017). Goal workshop 2017 Mexico 135 Evolución de los glaciares del Ecuador durante los últimos 60 años y su relación con el cambio climático. Conference paper: The role of Geosciences to societal development: A German-Latin American Perspective. GOAL Geo-Network of Latin American-German Alumini. P. 149. México: UANL-Monterrey-México.
Using an Urban Building Energy Modelling Towards a Carbon-Neutral Neighbourhood: A case study of Dublin Ireland
Authors: Buckley Niall , Mill s Gerald , Reinhart Christoph
Published: March 2021

The EU’s Green Deal has a goal of a climate-neutral Europe by 2050. Achieving this goal will require a comprehensive set of actions across all economic sectors, especially the building sector, which currently accounts for 40% of the energy consumed.  Residential energy use is a significant contributor, much of it due to the poorly insulated building stock. Making a ‘just transition’ to more energy-efficient cities requires a spatial approach that can address the correspondence of poor housing and people and the potential for energy innovation at a neighbourhood-scale. In this study, a geographic database of building archetypes is developed for use by the Urban Modelling Interface (Umi) to perform simulations of urban energy use intensity and test the efficacy of energy policies. Umi is applied to a neighbourhood of residential buildings in Dublin (Ireland), many of which perform poorly. Simulated annual energy use intensity is evaluated favourably using energy performance certificate data. Umi is used subsequently to design and test the efficacy of district-level energy policies; the results indicate that the most cost-effective mix of envelope retrofit and onsite energy production to achieve the Green Deal’s target of 60% reduction in greenhouse gas emissions by 2030 and 100% by 2050. The methodology shown here employs data and software that is publicly available for many EU countries.
The new Mediterranean Sea analysis and forecasting system including tides: description and validation
Authors: Clementi Emanuela , Goglio Anna Chiara , Aydogdu Ali , Pistoia Jenny , Escudier Romain , Drudi Massimiliano , Grandi Alessandro , Mariani Antonio , Lyubartsev Vladislav , Lecci Rita , Cretí Sergio , Masina Simona , Coppini Giovanni , Pinardi Nadia
Published: March 2021

The Mediterranean Analysis and Forecasting System operationally produces analyses and 10 days forecasts of the main physical parameters for the entire Mediterranean Sea and its Atlantic Ocean adjacent areas in the framework of the Copernicus Marine Environment Monitoring Service (CMEMS).

The system is composed by the hydrodynamic model NEMO (Nucleus for European Modelling of the Ocean) 2-way coupled with the third-generation wave model WW3 (WaveWatchIII) and forced by ECMWF (European Centre for Medium-range Weather Forecasts) atmospheric fields. The forecast initial conditions are produced by the OceanVar, a 3D variational data assimilation system which daily assimilates Sea Level Anomaly, vertical profiles of Temperature and Salinity from ARGO and XBT (upon availbility) observations. Moreover a heat flux correction using satellite SST is imposed.

The system has been recently upgraded by including tidal waves, so that the tidal potential is calculated across the domain for the Mediterranean Sea 8 major constituents: M2, S2, N2, K2, K1, O1, P1, Q1. In addition, tidal forcing is applied along the lateral boundaries in the Atlantic Ocean by means of tidal elevation estimated using the FES2014 global tidal model and tidal currents evaluated using TUGO (Toulouse Unstructured Grid Ocean) model. Moreover the data assimilation scheme now accounts for the tidal signal in the altimeter tracks.

The system has been validated comparing model results with satellite and in situ observations. A specific harmonic analysis has been performed comparing model sea level amplitudes and phases with respect to: tide gauges, TPXO global tidal model and literature, showing an overall good skill of all the considered tidal constituents. Moreover the ability of the system to predict sea level has been evaluated comparing the model solutions with respect to tide gauges in areas where recent extreme events occurred such as Venice Lagoon “Acqua Alta” in November 2019, Western Mediterranean Sea during Gloria storm in January 2020, Ionian Sea during Medicane Ianos in September 2020.
Modeling earthquake occurrence and recurrence for supercycles and clusters
Authors: Neely James , Salditch Leah , Stein Seth , Spencer Bruce
Published: March 2021

Long records often show large earthquakes occurring in supercycles—temporal clusters of seismicity, cumulative displacement, and cumulative strain release separated by less active intervals. Presently used earthquake recurrence models do not account for the time dependence and clustering. Poisson models assume that earthquake recurrence is time-independent, but seismicity studies have shown that time is needed to accumulate strain along a fault before another large earthquake. Seismic cycle/renewal models account for this time-dependence but assume that all strain is released after large earthquakes and fail to replicate clustered earthquake behavior. The resulting probability estimates for recurrence of the next earthquake thus depend crucially on whether the cluster is treated as ongoing or over.

In this study, we have reformulated our previously developed Long-Term Fault Memory (LTFM) earthquake model as a Markov process to better quantify long-term earthquake behavior and the probability of future earthquakes. In the LTFM model, the probability of a large earthquake reflects accumulated strain rather than elapsed time. The probability increases with accumulated strain (and time) until an earthquake happens, after which the probability decreases, but not necessarily to zero. This simple, strain-driven recurrence model yields realistic sequences of large earthquakes with periods of elevated activity followed by longer quiescence. Using the Markov formulation, we explore long-term earthquake behavior and how to use paleoseismic records to better estimate the recurrence and probability of future large earthquakes.
Revisiting Hotspots and Continental Breakup – Updating the Classical Three-arm Model
Authors: Stein Carol , Stein Seth , Gallahue Molly , Elling Reece
Published: March 2021

In two classic papers, Burke and Dewey (1973) and Dewey and Burke (1974) proposed that continental rifting begins at hotspots - domal uplifts with associated magmatism - from which three rift arms extend. Rift arms from different hotspots link up to form new plate boundaries along which the continent breaks up, generating a new ocean basin and leaving failed arms termed aulacogens within the continent.  In subsequent studies, hotspots became increasingly viewed as manifestations of deeper upwellings or plumes, which were the primary cause of continental rifting. We revisit this conceptual model and find that it remains useful, though some aspects require updates based on subsequent results.  Many three-arm systems identified by Burke and Dewey (1973) are now recognized to be or have been boundaries of transient microplates accommodating motion between diverging major plates. Present-day examples include the East African Rift system and the Sinai microplate.  Older examples include rifts associated with the opening of the South Atlantic in the Mesozoic and the North Atlantic Ocean over the last 200 Ma,  rifts in the southern U.S associated with the breakup of Rodinia, and intracontinental rifts formed within India during the breakup of Gondwanaland. The microplates form as continents break up, and are kinematically distinct from the neighboring plates, in that they move separately. Ultimately, the microplates are incorporated into one of the major plates, leaving identifiable fossil features on land and/or offshore. In many cases the boundaries of microplates during continental breakup are located on preexisting zones of weakness and influenced by pre-existing fabric, including older collisional zones. Hotspots play at most a secondary role in continental breakup, in that most of the associated volcanism reflects plate divergence, so three-arm junction points may not reflect localized upwelling of a deep  mantle plume.
Interplay between tectonic inheritance and salt tectonics in the tectono-sedimentary evolution of the Sahel basin (eastern Tunisia): implications for hydrocarbon prospectivity
Authors: Belkhiria Wajdi , Boussiga Haifa , Hamdi Nasr Imen , Amiri Adnen , Inoubli Mohamed Hédi
Published: March 2021

The Sahel basin in eastern Tunisia has been subject for hydrocarbon exploration since the early fifties. Despite the presence of a working petroleum system in the area, most of the drilled wells were dry or encountered oil shows that failed to give commercial flow rates. A better understanding of the tectono-sedimentary evolution of the Sahel basin is of great importance for future hydrocarbon prospectivity. In this contribution, we present integration of 2D seismic reflection profiles, exploration wells and new acquired gravity data. These subsurface data reveal that the Sahel basin developed as a passive margin during Jurassic-Early Cretaceous times and was later inverted during the Cenozoic Alpine orogeny. The occurrence of Triassic age evaporites and shales deposited during the Pangea breakup played a fundamental role in the structural style and tectono-sedimentary evolution of the study area. Seismic and gravity data revealed jointly important deep-seated extensional faults, almost along E-W and few along NNE–SSW and NW-SE directions, delimiting horsts and grabens structures. These syn-rift extensional faults controlled deposition, facies distribution and thicknesses of the Jurassic and Early cretaceous series. Most of these inherited deep-seated normal and transform faults are ornamented by different types of salt-related structures. The first phase of salt rising was initiated mainly along these syn-extensional faults in the Late Jurassic forming salt domes and continued into the Early and Late Cretaceous leading to salt-related diapir structures. During this period, the salt diapirism was accompanied by the development of salt withdrawal minibasins, characterized important growth strata due the differential subsidence. These areas represent important immediate kitchen areas to the salt-related structures. The later Late Cretaceous - Cenozoic shortening phases induced preferential rejuvenation of the diapiric structures and led to the inversion of former graben/half-graben structures and ultimately to vertical salt welds along salt ridges. These salt structures represent key elements that remains largely undrilled in the Sahel basin. Our results improve the understanding of salt growth in eastern Tunisia and consequently greatly impact the hydrocarbon prospectivity in the area.
Comparing onshore and offshore volumes of large igneous provinces associated with passive continental margins 
Authors: Stein Seth , Gallahue Molly , Stein Carol , Rooney Tyrone , Gomez-Patron Andie
Published: March 2021

The rifting of continents can lead to the initiation of seafloor spreading and the formation of passive margins. Magma-rich passive margins, which are defined as being underlain by enormous volumes of igneous rocks, are often associated with large igneous provinces (LIPs). However, the relationship between the igneous units found along these magma-rich passive margins, rifting processes, and LIPs is poorly understood.

We have developed the VOLMIR (VOLcanic passive Margin Igneous Rocks) dataset to investigate these relationships. VOLMIR is based on seismic reflection profiles in which the volumes and geometries of both shallow seaward dipping reflector (SDR) and deeper high velocity lower crustal (HVLC) units can be measured. We find a relatively consistent ratio of SDR to HVLC volumes, with SDR volumes about one third that of HVLC. This consistency suggests that the units are related during formation and may be used to provide insight into how such units form during continental rifting and breakup. Presumably, as magmas rise and erupt to the surface to form SDRs, the remaining high-density residuum or cumulate becomes the HVLC. The volumes of SDR units are moderately positively correlated with distance from the Euler pole, and weakly negatively correlated with distance from the nearest hotspot, suggesting that lithospheric processes play more of a role in late-stage continental rifting and breakup than hotspot/mantle plume processes.

The Mid- and South Atlantic Ocean breakups, and the resulting offshore volcanic passive margins, are temporally and spatially associated with the Central Atlantic Magmatic Province (CAMP) and Paraná-Etendeka LIP. Using VOLMIR, we estimate the amount of igneous material in the offshore volcanic passive and compare it to estimates for the adjacent on-land LIPs. The results indicate that a significant volume of volcanics exist in the offshore passive margins, increasing the inferred amount of volcanic output associated with the LIPs. Further studies will provide insight into the relationship between offshore passive margins and on-land LIPs, and perhaps provide further understanding on the role of magmatism in rifting processes.
Direct Aquatic Application of Crushed Dolomite Reduces CO2 Evasion in an Acidified River
Authors: Sterling Shannon , Nickerson Nick , Halfyard Edmund , Hart Kristin , Mallyon Deirdre , McCavour Caitlin , Rotteveel Lobke
Published: March 2021

Acidified rivers may have increased CO2 emissions because their low pH transforms inorganic carbon in the form of bicarbonate anions to CO2, which can evade to the atmosphere, thus interrupting the delivery inorganic carbon to the oceans, a key flux in the long-term carbonate silicate cycle. Enhanced weathering (EW) is a carbon dioxide removal (CDR) strategy aiming to increase drawdown of atmospheric CO2 through accelerated carbonation weathering of crushed minerals with targeted carbonate sequestration in oceanic stores. To date, EW research has been focused on terrestrial application of crushed minerals, and the CDR capability of enhancing weathering via addition of crushed minerals to rivers from lime dosers is essentially unexplored. Lime dosers have been used for decades to directly deposit crushed carbonate rock to rivers as a function of river flow in Norway and Nova Scotia, Canada, yet their potential as a CDR tool has yet to be verified in the field. In this study, we adapt CO2 flux sensors (eosFD) designed for soils to be deployed in rivers. We conducted field trials on the Killag River, Nova Scotia, upstream and downstream of a lime doser over a period of six weeks in the autumn of 2020. Preliminary analysis shows elevated CO2 evasion rates upstream of the lime doser and decreased evasion rates downstream. Aside from flood waves, CO2 evasion at the downstream (treated) site is reduced to almost zero for extended periods of time. Next steps are to identify whether the reduced CO2 evasion is due to CO2 drawdown via increased carbonation weathering of the crushed dolomite or through reduced CO2 evasion due to increased pH, or from a combination of the two processes. The results of this study may have implications for carbon credit programs for acidification mitigation and may encourage more widespread use of enhanced weathering as a CDR tool in rivers.
Probabilistic precipitation nowcast for flash flooding purposes across Australia: verification of a new version of Short-Term Ensemble Prediction System (STEPS)
Authors: Velasco-Forero Carlos , Pudashine Jayaram , Curtis Mark , Seed Alan
Published: March 2021

Short-term precipitation forecast plays a vital role for minimizing the adverse effects of heavy precipitation events such as flash flooding.  Radar rainfall nowcasting techniques based on statistical extrapolations are used to overcome current limitations of precipitation forecasts from numerical weather models, as they provide high spatial and temporal resolutions forecasts within minutes of the observation time. Among various algorithms, the Short-Term Ensemble Prediction System (STEPS) provides rainfall fields nowcasts in a probabilistic sense by accounting the uncertainty in the precipitation forecasts by means of ensembles, with spatial and temporal characteristic very similar to those in the observed radar rainfall fields. The Australian Bureau of Meteorology uses STEPS to generate ensembles of forecast rainfall ensembles in real-time from its extensive weather radar network. 

In this study, results of a large probabilistic verification exercise to a new version of STEPS (hereafter named STEPS-3) are reported. An extensive dataset of more than 47000 individual 5-minute radar rainfall fields (the equivalent of more than 163 days of rain) from ten weather radars across Australia (covering tropical to mid-latitude regions) were used to generate (and verify) 96-member rainfall ensembles nowcasts with up to a 90-minute lead time. STEPS-3 was found to be more than 15-times faster in delivering results compared with previous version of STEPS and an open-source algorithm called pySTEPS. Interestingly, significant variations were observed in the quality of predictions and verification results from one radar to other, from one event to other, depending on the characteristics and location of the radar, nature of the rainfall event, accumulation threshold and lead time. For example, CRPS and RMSE of ensembles of 5-min rainfall forecasts for radars located in mid-latitude regions are better (lower) than those ones from radars located in tropical areas for all lead-times. Also, rainfall fields from S-band radars seem to produce rainfall forecasts able to successfully identify extreme rainfall events for lead times up to 10 minutes longer than those produced using C-band radar datasets for the same rain rate thresholds. Some details of the new STEPS-3 version, case studies and examples of the verification results will be presented. 