bluuebunny/crossref_metadata_2025 huggingface dataset:
A new predictor for tsunami runup
Authors: Wronna Martin , Kânoğlu Utku , Baptista Maria Ana
Published: March 2020

We present a new Tsunami Runup Predictor (TRP). The TRP includes the length of the beach slope, the length of the accelerating phase of the wave plus the amplitude ratio for leading depression waves.

We use numerical and analytical tools to compute the runup for a dataset of 210 initial tsunami waveforms. In our tests, the slope angle of the beach varies between 1 and 5 degrees and the distance of the initial wave to the coast varies between 50 and 360 km. The results show a high correlation between the TRP and the dimensionless runup, enabling the definition of an empirical formula to predict the runup.

We further test the empirical formula using a set of past events with field data. The comparison of the empirical estimates with the runup measurements of post-tsunami surveys gives promising results.

The TRP allows estimating the tsunami runup in real-time once the offshore waveform is known.

The capacity to predict the maximum runup along the coast in real-time and include it in routine operations of Tsunami Early Warning Systems will constitute an enormous advance.

The authors would like to acknowledge the financial support  FCT through project UIDB/50019/2020 – IDL.
The mean state and variability of the North Atlantic circulation: a perspective from ocean reanalyses
Authors: Jackson Laura , Dubois Clotilde , Forget Gael , Haines Keith , Harrison Matt , Iovino Dorotea , Kohl Armin , Mignac Davi , Masina Ssimona , Peterson Drew , Piecuch Christopher , Roberts Chris , Robson Jon , Storto Andrea , Toyoda Takahiro , Valdivieso Maria , Wilson Chris , Wang Yiguo , Zuo Hao
Published: March 2020

The observational network around the North Atlantic has improved significantly over the last few decades with the advent of Argo and satellite observations, and the more recent efforts to monitor the Atlantic Meridional Overturning Circulation (AMOC) using arrays such as RAPID and OSNAP. These have shown decadal timescale changes across the North Atlantic including in heat content, heat transport and the circulation. 

However there are still significant gaps in the observational coverage, and significant uncertainties around some observational products. Ocean reanalyses integrate the observations with a dynamically consistent ocean model and are potentially tools that can be used to understand the observed changes. However the suitability of the reanalyses for the task must also be assessed.
We use an ensemble of global ocean reanalyses in comparison with observations in order to examine the mean state and interannual-decadal variability of the North Atlantic ocean since 1993. We assess how well the reanalyses are able to capture different processes and whether any understanding can be inferred. In particular we look at ocean heat content, transports, the AMOC and gyre strengths, water masses and convection. 

 
The 1513 Monte Crenone Rock Avalanche. Numerical model and geomorphological analysis
Authors: De Pedrini Alessandro , Ambrosi Christian , Scapozza Cristian
Published: March 2020

The Monte Crenone rock avalanche of 30 September 1513 is one of the most catastrophic natural events in Switzerland and throughout the Alps. The enormous mass of rock that broke away from the western slope of Pizzo Magn or Monte Crenone, estimated at 50-90 million cubic metres, caused the complete damming of the course of the Brenno river, leading to the formation of a basin that extended from Biasca to the Castello di Serravalle in Semione (De Antoni et al. 2016). On 20 May 1515 the basin formed behind the dam overflowed, giving rise to a wave of more than 10 meters high that led to devastation in the territories downstream to reach Lake Maggiore (Scapozza et al. 2015).

In this project, we analyze the dynamics of the 1513 rock avalanche, trying to reconstruct the event through a numerical model, calculated with the software RAMMS::Debrisflow (RApid Mass Movement Simulation) provided by the Federal Institute for the Study of Snow and Avalanches (SLF/WSL).

The realization of the numerical model was preceded by the reconstruction of the topography before the landslide. This first phase of work, included a geological survey of the landslide body, the analysis of digital data (orthophotos, digital topographic maps, shaded model derived from swissALTI3D) and the collection of previous historical data.

The observation of the stratigraphic data obtained from the 701.27, 701.30 and 701.31 boreholes (part of the geotechnical studies for the Chiasso-San Gottardo highway) of the GESPOS database (GEstione Sondaggi, POzzi e Sorgenti) of the Institute of Earth Sciences SUPSI was essential to understand the landslide body thickness and volume in the deposition zone.

From the first phase of data collection and interpretation, we then moved on to the actual reconstruction of the digital model of the terrain before the landslide. This operation was carried out using ESRI's ArcGIS software, which made it possible recreating multiple models of the pre-event topography and thus finding the most realistic solution applicable to the subsequent RAMMS model.
Evaluation of the University of Victoria Earth System Climate Model version 2.10 (UVic ESCM 2.10)
Authors: Mengis Nadine , Keller David P. , MacDougall Andrew , Eby Michael , Wright Nesha , Meissner Katrin J. , Oschlies Andreas , Schmittner Andreas , Matthews H. Damon , Zickfeld Kirsten
Published: March 2020

The University of Victoria Earth system climate model of intermediate complexity has been a useful tool in recent assessments of long-term climate changes including paleo-climate modelling. Since the last official release of the UVic ESCM 2.9, and the two official updates during the last decade, a lot of model development has taken place in multiple groups. The new version 2.10 of the University of Victoria Earth System Climate Model (UVic ESCM), to be used in the 6th phase of the coupled model intercomparison project (CMIP6), presented here combines and brings together multiple model developments and new components that have taken place since the last official release of the model. To set the foundation of its use, we here describe the UVic ESCM 2.10 and evaluate results from transient historical simulations against observational data. We find that the UVic ESCM 2.10 is capable of reproducing well changes in historical temperature and carbon fluxes, as well as the spatial distribution of many ocean tracers, including temperature, salinity, phosphate and nitrate. This is connected to a good representation of ocean physical properties. For the moment, there remain biases in ocean alkalinity and dissolved inorganic carbon, which will be addressed in the next updates to the model.
Identifying opportunities for sustainable phosphorus management in Northern Ireland with substance flow analysis
Authors: Rothwell Shane , Forber Kirsty , Johnson Chris , Doody Donnacha , Withers Paul
Published: March 2020

In common with most national agricultural systems, phosphorus (P) inputs are essential for production of crops and livestock in Northern Ireland (NI). However, the negative environmental impacts on their aquatic environments of inappropriate P management both in agriculture and the wider food system are widely acknowledged. Recent gains in reducing P loading to fresh waters through regulatory intervention are now reversing (Northern Ireland Environmental Statistics Report, DAERA 2018) suggesting the need for additional approaches that improve the sustainability of P use in the NI food system. Such approaches should ensure that P entering the food system (e.g. as food, fertilisers and animal feed) is efficiently recycled back into the system to ‘close the P cycle’, and thus reduce the demand for imported P. Furthermore, minimising P losses from different stages of the food system are critical to mitigating negative environmental impacts. To effectively achieve this, the flows, stores and losses of P within the food system must first be understood. Here, we report on a P substance flow analysis (SFA) undertaken for NI for the year 2017, that provided a focus to empower stakeholders to explore options to change P stewardship in the NI food system. Total P import to the NI food system in 2017 as food, feed, fertiliser and chemical P was 19096 t (10.21 kg person-1 yr-1), total P exports were 8097 t (4.33 kg person-1 yr-1) leaving a system surplus of 10999 t (5.88 kg person-1 yr-1). Of this surplus, 923 t of P (0.49 kg person-1 yr-1 or 8%) was consumed in food by the population of NI, 7959 t (72%) accumulated in agricultural soil as excess application, 1528 t (14%) were lost to fresh and coastal waters and 1189 t (11%) were disposed in landfill, demonstrating the current imbalance of P use in NI. This P SFA model created a framework of understanding to engage key stakeholders, in scenario analysis, to explore opportunities for improving the sustainability of P use in the NI food system.
Recent Progress and Plans for Improvement of ILRS Infrastructure and Data Product Delivery
Authors: Pearlman Michael R. , Noll Carey , Pavlis Erricos , Otsubo Toshimichi , Torre Jean-Marie , Schreiber Ulrich , Kirchner Georg , Steindorfer Michael Steindorfer
Published: March 2020

The International Laser Ranging Service (ILRS) is improving its services through network expansion and continuous upgrades of its modeling and analysis approaches. New ground stations are being deployed with higher repetition rate systems, more efficient detection, and increased automation; new technologies are also being adopted at some of its legacy stations. In addition, the roster of tracking missions is rapidly expanding. The top priority for the Service continues to be its contribution to the reference frame development, but of increasing importance is also the tracking of GNSS satellites, including the anticipated deployment of the new GPS III constellation over this decade. These requirements are being reflected in new system designs and updates. Stations are also being adapted to accommodate ground and space-time synchronization. A few stations continue with their lunar laser ranging activities while several others have begun testing their ability to do lunar ranging in the future. About a dozen stations are active in space-debris tracking for studies of orbital dynamics and reentry predictions. New tools and procedures have been implemented to improve the quality of SLR data and derived products, and to expedite the resolution of engineering issues. Work also continues on the design and building of improved retroreflector targets to maximize data quality and quantity.

 This paper will give an overview of activities underway within the Service, paths forward and presently envisioned, and current issues and challenges.
VENM: An Algorithm to Accurately Calculate Neutral Slopes and Gradients
Authors: Groeskamp Sjoerd , Barker Paul , McDougall Trevor , Abernathey Ryan , Griffies Stephen
Published: March 2020

Mesoscale eddies stir along the neutral plane, and the resulting neutral diffusion is a fundamental aspect of subgrid-scale tracer transport in ocean models. Calculating neutral diffusion traditionally involves calculating neutral slopes and three-dimensional tracer gradients. The calculation of the neutral slope traditionally occurs by computing the ratio of the horizontal to vertical locally referenced potential density derivative. However, this approach is problematic in regions of weak vertical stratification, prompting the use of a variety of ad hoc regularization methods that can lead to rather nonphysical dependencies for the resulting neutral tracer gradients.

Here we introduce VENM; a search algorithm that requires no ad hoc regularization and significantly improves the numerical accuracy of calculating neutral slopes, neutral tracer gradients, and associated neutral diffusive fluxes. We compare and contrast VENM against a more traditional method, using an independent objective neutrality condition combined with estimates of spurious diffusion, heat transport, and water mass transformation rates. VENM is more accurate, both physically and numerically, and should form the basis for future efforts involving neutral diffusion calculations from observations and possibly numerical model simulations.
Archeomagnetic studies of fired ceramics from Sakhtysh-I and Sakhtysh -II settlements (Ivanovo Region, Russia)
Authors: Pilipenko Olga , Nachasova Inga , Tsetlin Yuri , Filina Eugeniya
Published: March 2020

With the goal to obtain new data of geomagnetic field intensity in the Bronze Age in the Eastern Europe the arheomagnetic study of fired ceramic samples from the settlements Sakhtysh-I and Sakhtysh - II were done. The settlements Sakhtysh-I and Sakhtysh -II are placed in Teikovo district of the Ivanovo region of Russia (56о48′ N, 40о33′ E). Archeological excavations of ancient ceramics were carried out by the Upper Volga Archeological Expedition of the Institute of Archeology RAS. The studied collection of pottery fragments belongs to three cultures: the Fatyanovo, the Fatyanoid (or the Fatyanivo-like) and the Textile ceramics culture.  The composition of the ferromagnetic fraction presented in the studied archaeological samples have been performed by the complex of standards petromagnetic methods. The thermomagnetic analysis (TMA) in dependence of the saturation magnetic moment on temperature and determination of the Curie points were carry out. Thus based on TMA one can conclude that the main carrier of the magnetisation of the samples is relatively resistant to heat maghemite. The size of grains lies in a pseudo single domain area. The determination of the ancient magnetic field intensity was carried out by modified Thellier method.  Based on the carbon-isotope dating the age of pottery fragments corresponds to the ~ 2000-700 years BC, and we can construct a curve of paleointensity variations of the geomagnetic field from the age.  The data obtained for this period can provide new information about variations of the geomagnetic field intensity during the Bronze Age, which will make it possible to specify the character of changes in geomagnetic field. Earlier for the time interval II millennium BC a certain amount of the geomagnetic field intensity data were obtained in the Russian Plain region. Due to the uncertainty of the dating, these data allowed us to evaluate only the general features of geomagnetic  field intensity variations.  Rapid sharp changes in field intensity occurred with an increase in the average level of the field intensity compared with the level in the previous two millennia. This work was supported by the Russian Foundation for Basic Research, project no. 19-55-18006 and the State task of the Schmidt Institute of Physics of the Earth RAS.
Analysis of the impact of biomass burning emissions on global ozone production in the upper troposphere with MOCAGE CTM and IAGOS airborne data.
Authors: Cussac Martin , Marécal Virginie , Thouret Valérie , Josse Béatrice
Published: March 2020

The UTLS (Upper Troposphere/Lower Stratosphere) is a key layer of the atmosphere as its chemical composition impacts both the troposphere and the stratosphere, and therefore plays a significant role in the climate system. Ozone at this altitude for instance plays a great role on surface temperature. Unlike in the stratosphere; it can be produced from the photolysis of precursors originating in the troposphere; mainly nitrous oxides (NOx) and carbon monoxide (CO) at this pressure range. Biomass burning emissions in particular are likely to play a significant role in the quantities of these species in the upper troposphere and thus impacting ozone balance. This effect is investigated thanks to the global chemistry transport model MOCAGE. Because of the strong vertical gradients in this layer of the atmosphere, well resolved in-situ observation dataset are valuable for model evaluation. As of measurements used to validate MOCAGE results, IAGOS in-situ measurements from equipped commercial aircraft were chosen for their fine vertical resolution as well as their wide geographical coverage. Using both of these tools, upper tropospheric air composition is studied, with a focus on ozone precursors and production linked to biomass burning emissions.

Firstly is investigated the direct impact of biomass burning emissions on CO concentration in the upper troposphere, as it is both a good tracer of wildfire plumes in the atmosphere and it plays a role in the upper troposphere chemical balance. For this purpose MOCAGE simulations spaning over the year of 2013 where biomass burning emissions were turned on and off are compared to estimate a contribution to upper tropospheric CO. These simulations were validated using all the available data from the IAGOS database. It was found that biomass burning impacted CO levels globally, with the strongest enhancement happening above the most emitting areas (equatorial Africa and the Boreal forests). The importance of a fast vertical transport pathway above the fires was also highlighted with the possible occurrence of pyroconvection in addition to deep convection. Secondly, other chemical species related to ozone production were looked upon. Peroxyacetyl Nitrates (PAN) for instance were found to be impacted by biomass burning as it is a product of NOx oxidation as well as the main "reservoir" specie for NOx in the upper troposphere. Ultimately, ozone production resulting from biomass burning emissions is investigated, both in biomass burning plumes encountered by IAGOS aircraft, and on a more global scale using the MOCAGE simulations.
Lidar observations of volcanic aerosol over the UK since June 2019
Authors: Vaughan Geraint , Wareing David , Ricketts Hugo
Published: March 2020

On 22 June 2019, the Raikoke volcano in the Kuril Islands erupted, sending a plume of ask and sulphur dioxide into the stratosphere. A Raman lidar system at Capel Dewi, UK (52.4°N, 4.1°W) has been used to measure the extent and optical depth of the stratospheric aerosol layer following the eruption. The lidar was modified to give it much enhanced sensitivity in the elastic channel, allowing measurements up to 25 km, but the Raman channel is only sensitive to the troposphere. Therefore, backscatter ratio profiles were derived by comparison with aerosol-free profiles derived from nearby radiosondes, corrected for aerosol extinction. Small amounts of stratospheric aerosol were measured prior to the arrival of the volcanic cloud, probably from pyroconvection over Canada. Volcanic ash began to arrive as a thin layer at 14 km late on 3 July, extending over the following month to fill the stratosphere below around 19 km. Aerosol optical depths reached around 0.03 by mid-August and continued at this level for the remainder of the year. The location of peak backscatter varied considerably but was generally around 15 km. However, on one notable occasion on August 25, a layer around 300 m thick with peak lidar backscatter ratio around 1.5 was observed as high as 21 km.
New constraints on the pre-Alpine evolution of the Austroalpine basement: A LA-ICP-MS U/Pb zircon study on the Schladming nappe
Authors: Haas Isabella , Kurz Walter , Gallhofer Daniela , Hauzenberger Christoph
Published: March 2020

The crystalline basement of the Schladming Nappe, Eastern Alps, is part of the Silvretta-Seckau Nappe system. It consists mainly of ortho- and paragneisses which were intruded by slightly overprinted granites and granodiorites. On top of the basement a sedimentary cover (e.g. Rannach Formation) containing quartzites and meta-conglomerates is usually developed.

In the last decade the Schladming Nappe has not stirred interest as there is no precise geochronological data available and the metagranitoids are assumed to be part of the widespread magmatic intrusions connected to the Variscian orogeny. These general presumptions will be examined by new U/Pb zircon data in order to complete the knowledge of the pre-Alpine and Alpine magmatic and tectonic evolution of the Schladming nappe system. Additionally, major and trace elements geochemistry will provide information on the origin and evolution of the magmatic source.

In order to better define the sedimentary cover sequence a provenance study including dating of detrital zircons is undertaken. By dating these detrital zircons, the minimum deposition ages of the sedimentary precursor rocks as well as information about the paleogeographic positions of these units will be obtained.
Transient signs in bedrock rivers of the southernmost Brazilian and Uruguayan shields
Authors: Cardoso Junior Marcio , Santos da Silveira Ariane , Rodrigues de Vargas Mateus , Marques Teixeira de Oliveira José Manuel , Lôndero Vinicius , Eloy Barbosa Dante Vinicius , Bertoldi de Oliveira Luiz Felipe , Ferreira Alves Lucas Gabriel , Cambri Fredere Aline
Published: March 2020

The Earth’s surface is a result of tectonic and erosional processes shaping landscapes and preserving transient signs of different evolutionary stages. These transient signs are produced by a gradual adjustment of rivers to an equilibrium stage through channel incision and uplift. The processes effects have different magnitudes according to lithologic contrasts and base level changes that combined influence in disequilibrium phases of bedrock rivers. A integrate study of geomorphic indices in bedrock rivers of the southernmost Brazilian and Uruguayan Shields is developed to identify key signs of transience associated to those surface process and compared between the contrasting drainage basins results. These indices are combined to published thermochronology ages to build a landscape evolution model of these shields. The study area is essentially composed by igneous-metamorphic rocks of Precambrian ages of the Dom Feliciano Belt amalgamated during the Proterozoic-Phanerozoic boundary in the Brasiliano Orogeny. Digital elevation models are used to extract geomorphic indices through interactive MATLAB tools and compared the erosional stages and uplifted regions. This study reveals lineament structures signatures aligned with knickpoints as indicator of the suture zones of distinct terranes in the area. These terranes also feature different erosional stages according to hypsometric results. Thermochronological data support the tectonic framework of three uplift phases starting by the exhumation of western terranes during Devonian ages. A second stage is connected to an uplift preceding the Pangea breakup with the reactivation of Brasiliano Orogeny lineaments. And, the third phase is associated with plate flexural responses of the adjacent oceanic crust during the Cenozoic Era. Finally, the evolutionary model shows strong transient signs in the north region of the studied area indicating a locus of a possible stronger uplift process. In this part of the Dom Feliciano Belt all exhumation phase are evidenced by transient signs of disequilibrium. Differently, the southern region in the Uruguayan Shield shows a more denudated landscape with more mature stages of erosional process.
Flow-dependent sub-seasonal forecast skill for Atlantic-European weather regimes
Authors: Büeler Dominik , Quinting Julian F. , Wandel Jan , Grams Christian M.
Published: March 2020

The continuous increase of computational power and improvement of numerical weather prediction systems in recent decades has allowed extending the operational weather forecast horizon into sub-seasonal time scales (10 – 60 days). On these scales, quasi-stationary, persistent, and recurrent large-scale flow patterns, so-called weather regimes, explain most of the regional surface weather variability and are thus of primary interest in sub-seasonal forecasting for the respective region. Here, we assess the skill of sub-seasonal reforecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) for predicting 7 year-round weather regimes in the Atlantic-European region. We primarily show that forecast skill considerably differs for different flow situations and seasons. We further elucidate the effect of model calibration on forecast skill: simply removing the model bias is shown to hardly affect and for some flow situations even reduce forecast skill, which indicates that flow-dependent model calibration techniques might be more useful for sub-seasonal weather regime forecasts. Finally, we give an outlook on how lower-frequency climate modes such as the stratospheric polar vortex as well as midlatitude synoptic-scale activity such as warm conveyor belts may enhance or dilute flow-dependent forecast skill.
Provenance of the Paleozoic-Mesozoic siliciclastic rocks of the Istanbul Zone: Constraints on the location of the Rheic suture in Turkey
Authors: Akdoğan Remziye , Hu Xiumian , Okay Aral I. , Topuz Gültekin
Published: March 2020

The Istanbul Zone (NW Turkey) is regarded as the eastward elongation of Avalonia in Central Europe. Its Paleozoic stratigraphy is characterized by continuous sedimentation from Early Ordovician to Late Carboniferous. However, the Intra-Pontide Suture between the Istanbul and Sakarya zones is regarded as a Neotethyan Suture representing an oceanic domain of Permo-Triassic to Cretaceous age. Here, we present U-Pb ages and Lu-Hf isotopic compositions of the detrital zircons from the Upper Silurian-Lower Devonian, Upper Carboniferous, Permian and Upper Triassic sandstones of the Istanbul Zone. Detrital zircon ages from the Upper Silurian-Lower Devonian sandstone are dominated by Mesoproterozoic zircons (1950-900 Ma), with subordinate peaks at the latest Neoproterozoic to Silurian and Mid-Archean (2850-2750 Ma) confirming its Avalonian affinity. Detrital zircons from Carboniferous to Triassic sandstones yielded a major peak at Carboniferous-Early Permian (360-270 Ma) and a minor peak at Late Neoproterozoic-Cambrian (700-480 Ma) while Mesoproterozoic zircons become insignificant. The εHf (t) values of the detrital zircon grains from Upper Silurian-Lower Devonian, Upper Carboniferous, and Upper Triassic sandstones exhibit a wide range from -21.3 to +11.7, and over 62% of zircon grains have negative values, suggesting mixing derivation of both mantle and crustal melts. Apart from the Permo-Triassic magmatism, the Istanbul Zone is devoid of Carboniferous igneous and metamorphic events. Therefore, abundant Carboniferous zircons and disappearance of the Mesoproterozoic zircons in the Carboniferous to Upper Triassic clastic rocks of the  Istanbul Zone require juxtaposition with a continental domain similar to the Sakarya and Rhodope‐Strandja zones, which are characterized by widespread Carboniferous magmatism. We suggest that the Intra-Pontide Suture probably represents trace of the Rheic Suture in Turkey, along which Avalonia and Armorica collided during Early Carboniferous.

Key words: Intra-Pontide Suture, Istanbul Zone, Rheic Suture, detrital zircon, U-Pb ages, provenance, Hf isotopes
Compaction versus reactive flow: How does melt fraction change in crustal mush reservoirs?
Authors: Hu Haiyang , Jackson Matthew
Published: March 2020

Chemical differentiation requires the relative motion of melt and crystals during multicomponent phase change.  Compaction is often invoked as the mechanism that allows this in crystal rich ‘mush’ reservoirs.  Compaction is a term used broadly to describe the coupled processes of buoyancy-driven melt flow through permeable crystalline matrix and matrix deformation in response to the extraction or accumulation of melt.  One key challenge to melt segregation models that invoke compaction is that textural evidence for crystal deformation in the residual material left after melt extraction is largely absent (Holness, 2018).

Here, we test the relative contribution of compaction and reactive flow to melt fraction change in crustal mush reservoirs using a modified version of the reactive flow model of (Solano et al., 2014).  Reactive flow changes melt, solid and bulk composition and is essential to chemical differentiation in crustal mush reservoirs but has been largely neglected in models of melt segregation.  We find that melt fraction changes in response to reactive flow can be as important as those caused by compaction, irrespective of the phase behaviour tested.  That compaction may account for only half the melt fraction change observed in mush reservoirs could help to explain why textural evidence for mush deformation remains enigmatic.

 

References
Holness, M. B. (2018). Melt segregation from silicic crystal mushes: a critical appraisal of possible mechanisms and their microstructural record. Contributions to Mineralogy and Petrology, 173(6):48.
Solano, J. M. S., Jackson, M. D., Sparks, R. S. J., and Blundy, J. (2014). Evolution of major and trace element composition during melt migration through crystalline mush: Implications for chemical differentiation in the crust. American Journal of Science, 314(5):895–939.

 
Climate change impacts on the water, energy, and food nexus: a global quantitative assessment
Authors: Merks Joreen , Yalew Seleshi , Ludwig Fulco
Published: March 2020

Understanding the global interactions between water, energy and food production under climate change is crucial to identify arising synergies and conflicts between these sectors. Existing literature mainly focuses on the water-energy-food (WEF) nexus at a case study level as well as at policy and decision making level. Global quantitative assessments of the WEF nexus are still limited. Quantifying the nexus is challenging because it requires a framework which includes knowledge from three different fields. This becomes even more complex if we want to incorporate future climate projections and look at a global scale.

Two approaches can be followed to quantify the WEF nexus. One is to use an integrated assessment model, a model that includes modules for water, energy and food. Another approach is to use separate cutting edge models from each field and bring these different model outputs together. The Inter Sectoral Impact Model Intercomparison Project (ISIMIP) gives us the opportunity to apply this second approach. In ISIMIP, many model groups provide impact model data for a variety of sectors with the same climate forcing and climate scenarios on a global scale. This means we can not only use data from the water, energy and food sectors, but we can also use multiple models per sector. This approach allows us to use unique insights from the sectoral inter-comparison studies and see their implications for the WEF nexus.  

This study aims to identify WEF nexus ‘hot spots’ and how they might change in the future. Here we want to focus on locations where WEF conflicts might arise as well as spots with high development potential. We do this by, first, looking at global spatially distributed demand and supply model data per sector finding areas of surplus and deficit. Second, we combine them into several maps displaying integrated WEF nexus hot spots and their progression into the future. This study is meant to create a better global understanding of the interactions between water, energy and food sectors and how they will develop over time. The resulting maps identify regions of conflict or synergy, and can be used not only as a basis for future studies assessing resource conflicts but also as an indicator of where to harness arising opportunities.
Elastic geobarometry of multiphase inclusions
Authors: Musiyachenko Kira , Murri Mara , Angel Ross John , Prencipe Mauro , Alvaro Matteo , van Schrojenstein Lantman Hugo
Published: March 2020

Elastic geobarometry allows one to recover the PT entrapment conditions of a host-inclusion pair from measurements of the residual pressure of the inclusion which develops upon exhumation due to differences of its thermo-elastic properties from the host (Angel et al., 2015). At the present, calculations assume that the inclusion is a single phase. For a soft inclusion in a stiffer host, the volume change of a free inclusion crystal would be greater than that of the host, which leads to the inclusions being compressed into a smaller volume than expected and thus positive inclusion pressures. Conversely, an inclusion stiffer than the host should develop a negative pressure.

Rutile-in-garnet would be a good candidate for elastic geobarometry because of its common occurrence in high-pressure high-temperature (HP-HT) metamorphic rocks, its simple structure and chemistry and its broad PT stability field. However, recent work by Zaffiro et al. (2019) demonstrated that rutile trapped in garnet should always exhibit negative pressure upon exhumation because rutile is stiffer than garnet, making this pair unsuitable for elastic geobarometry.

Nevertheless, rutile inclusions in garnets from the Pohorje eclogite seem to challenge this thermodynamic prediction. Rutile inclusions show no Raman peak shifts relative to free crystals within the measurement error, despite there being strain birefringence in the garnet host around the rutile which indicates the relaxation of stressed inclusions. High resolution 3D Raman mapping on one of these rutile inclusions revealed the presence of tiny (2-3 µm thick) amphibole crystals located between the garnet and rutile, with the amphibole occupying about 25-30% of the volume of the inclusion. The presence of this amount of amphibole lowers the bulk modulus of the composite inclusion (rutile + amphibole) to less than the bulk modulus of the garnet, hence leading to pressurization of the inclusions upon exhumation. This study shows that careful characterization of host inclusion systems, linked to thermodynamic modelling, is thus necessary to interpret residual pressures (Pinc) in terms of entrapment conditions.

This project has received funding from the European Research Council under the H2020 research and innovation program (N. 714936 TRUE DEPTHS to M. Alvaro).

References:

Angel R.J. et al. 2015. J. Metamorph. Geol., 33(8), 801-813.

Zaffiro G. et al. 2019.  Mineralogical Magazine, 83(3), 339-347.
Ruminations of the Urban Climate Field and Hopes for the Future
Authors: brazel anthony
Published: March 2020

In the recent book entitled Urban Climates (2017) by T. Oke, G. Mills, A. Christen and J. A. Voogt, there is an Epilogue section on the History of Urban Climatology (pp 454-459) which states its scientific study dates from the early 19th century (as we know, from Luke Howard’s famous works) and can be divided into four periods of activity: (a) before 1930, pioneering climatographies of selected cities and weather elements, (b) 1930-1965, the growth of micro- and local climatology of climate differentiation and new field techniques, (c) 1965 to ca. 2000, explosive increase in research interest, closer links to meteorology and emergence of physically-based models of the urban atmosphere, and (d) 2000 and beyond, a maturing of the science into a predictive science, a period called one of consolidation and prediction.   With a proliferation of interests, new entities were formed during (d) – e.g., the International Association for Urban Climate and the Board on the Urban Environment of the AMS. They are dedicated to furthering scientific work in the urban climate and meteorology field and fostering cooperation between all interested scientists and practitioners. Through experiencing period (c) and now (d) with colleagues, students, administrators, practitioners, and the public (although now as an emeritus faculty in geography and urban planning) and being exposed to these organizations, it is this latter mission of the urban climate community I would like to highlight. It is a hope that the cooperative spirit of world  scientists and practitioners is further intensified (e.g, through CitiesIPCC and other academic and applied entities) in order to achieve major global-to-local solutions for our world cities. Technologies are exploding; the hope is that there is a concomitant explosion of practice.
Permeability of growing sea ice - observations, modelling and some implications for thinning Arctic sea ice
Authors: Maus Sönke
Published: March 2020

The permeability of sea ice is an important property with regard to the role of sea ice in the earth system. It controls fluid flow within sea ice, and thus processes like melt pond drainage, desalination and to some degree heat fluxes between the ocean and the atmosphere. It also impacts the role of sea ice in hosting sea ice algae and organisms, and the uptake and release of nutrients and pollutants from Arctic surface waters. However, as it is difficult to measure in the field, observations of sea ice permeability are sparse and vary, even for similar porosity, over orders of magnitude. Here I present progress on this topic in three directions. First, I present results from numerical simulations of the permeability of young sea ice based on 3-d X-ray microtomographic images (XRT). These results provide a relationship between permeability and brine porosity of young columnar sea ice for the porosity range 2 to 25 %. The simulations also show that this ice type is permeable and electrically conducting down to a porosity of 2 %, considerably lower than what has been proposed in previous work. Second, the XRT-based simulations are compared to predictions based on a novel crystal growth modelling approach, finding good agreement. Third, the permeability model provides a relationship between sea ice growth velocity and permeability. Based on this relationshiop interesting aspects of the growth of permeable sea ice can be deduced: The predictions consistently explain observations of the onset of convection from growing sea ice. They also allow for an evaluation of expected permeability changes for a thinning sea ice cover in a warmer climate. As the model is strictly valid for growing and cooling sea ice, the results are mostly relevant for sea ice desalination processes during winter. Modelling permeability of summer ice (and melt pond drainage) will require more observations of the pore space evolution in warming sea ice, for which the present results can be considered as a resonable starting point.
Retrieving H2O/HDO above clouds using TROPOMI SWIR measurements
Authors: Schneider Andreas , Borsdorff Tobias , aan de Brugh Joost , Lorente Delgado Alba , Landgraf Jochen
Published: March 2020

The current scientific H2O/HDO data product from short-wave infrared reflectance measurements by the Tropospheric Monitoring Instrument (TROPOMI) is retrieved using a profile-scaling approach with a forward model which ignores scattering. Since water is too dark in the short-wave infrared, the coverage is limited to clear-sky scenes over land. Clouds are relatively bright in this spectral region, thus retrievals over low clouds will greatly enlarge the coverage. To do so, retrievals using a forward model which accounts for scattering and fitting effective cloud parameters additionally to the trace gases are examined. Inferred effective cloud parameters are compared with measurements by the Visible Infrared Imaging Radiometer Suite (VIIRS) to optimise the cloud model. Furthermore, the impact on the validation of the retrieved H2O/HDO columns with collocated measurements by the Total Carbon Column Observing Network (TCCON) is discussed.
Sudden Stratospheric Warmings - The Role of Radiation Revealed Through an Energy Budget Analysis
Authors: Bloxam Kevin
Published: March 2020

Sudden stratospheric warmings (SSWs) are impressive events that occur in the winter hemisphere's polar stratosphere and are capable of producing temperature anomalies upwards of +50 degrees within a matter of days. While much work has been dedicated towards determining how SSWs occur and their ability to interact with the underlying troposphere, one under-explored aspect of SSWs is the role of radiation. Using a radiative transfer model and an energy budget analysis for distinct layers of the stratosphere, this work accounts for the radiative contribution to the removal of the anomalous energy associated with SSWs. In total, 19 events are investigated over the 1979-2016 period. This work reveals that in the absence of dynamical heating following major SSWs, longwave radiative cooling dominates and often results in a strong negative temperature anomaly. The stratospheric temperature change driven by the radiative cooling is characterized by an exponential decay of the temperature anomaly with an increasing e-folding time of 6.3 ± 2.6 to 21.6 ± 8.3 days from the upper to lower stratosphere. This work also demonstrates a negligible impact that water vapour and ozone have on the longwave and shortwave radiative heating rates during SSWs when the concentrations of these gases are perturbed from their climatological state.
Hard to measure, hard to model: Using information theory to understand turbulent heat fluxes
Authors: Bennett Andrew , Nijssen Bart
Published: March 2020

Measurements and models constitute the core modes of understanding environmental processes, where a major paradigm of doing science involves confronting hypotheses (represented by models) with data from measurements. Of course, both models and measurements involve uncertainties which can make reasoning about the validity of our hypotheses difficult. This difficulty is exemplified in the study of turbulent heat fluxes where measurements made by eddy-covariance towers often have energy balance gaps and simple regression models often outperform the most sophisticated physically-based models. Our study addresses these issues by identifying the conditions in which either or both models and measurements break down as well as identify potential reasons for these breakdowns.

We use the Structure for Unifying Multiple Modeling Alternatives (SUMMA) to develop an ensemble of models representing multiple hypotheses about how turbulent heat fluxes are generated and compare them against measurements from FluxNet towers at a number of hydro-climatically diverse sites. We evaluate the models against the measurements using both traditional error measures as well as with a general framework based on information theory and conditional probabilities. Extending this base analysis, we compute conditional mutual information of the modeled and observed relationships between turbulent heat fluxes and other meteorological variables (such as shortwave radiation, air temperature, and humidity). This allows us to go further than traditional error measures to explore how well the modeled relationships match the observed, providing a proxy for process correctness. We perform this analysis for a variety of conditions. We first analyze how much information the meteorological variables provide to the observed heat fluxes to estimate the robustness of the measurements. We then compare this with the amount of information that the meteorological variables provide to the simulations to determine whether there are significant deviations between the shared information from the simulations to the observations. This analysis is used to provide recommendations for post processing observations as well as identifying possible process deficiencies in our models.
Argo Beyond 2020: Towards a global, full-depth multidisciplinary array
Authors: Wijffels Susan , Suga Toshio , Roemmich Dean ,   Argo Steering Team
Published: March 2020

Starting in 2000, Argo reached global coverage in 2007 and has sustained a globally distributed array of ~ 3000 profiling floats for almost two decades. This Argo array delivers ocean temperature and salinity profiles from the sea surface to 2000 dbar roughly 300km apart every 10 days in realtime. Just as the present Argo array originated from an opportunistic mix of developments in both technology and data management, a new step-change in global ocean observing is now possible. Advances in platform and sensor technologies presents a new opportunity to (i) improve Argo’s global reach and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems – all within the context of a comprehensive Argo data system. Each of these enhancements are evolving along a path from experimental deployments to regional pilot arrays to global implementation.The ultimate objective is to implement a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System. The integrated system will deliver enhanced operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities.
Concentration-discharge relationships vary among hydrological events, reflecting differences in event characteristics
Authors: Knapp Julia , von Freyberg Jana , Studer Björn , Kiewiet Leonie , Kirchner James
Published: March 2020

Studying the response of streamwater chemistry to changes in discharge can improve our understanding of how catchments store and release water and solutes. Previous studies have determined concentration-discharge (cQ) relationships from long-term, low-frequency data for many different solutes. These analyses, however, provide little insight into the coupling of solute concentrations and flow during individual hydrologic events. Although intra-event cQ relationships have been determined for selected solutes and storm events, they have rarely been investigated across a wide range of solutes and over extended periods of time. Thus, little is known about how intra-event and longer-term cQ relationships may differ, potentially providing different perspectives on processes regulating transport through the landscape.

We present cQ relationships of 14 different solutes, ranging from major ions to trace metals, as well as electrical conductivity, in the Swiss Erlenbach catchment (0.7 km2). From a 2-year time series of sub-hourly solute concentration measurements, we determined long-term cQ relationships for each solute. We compared these to cQ relationships spanning the hydrograph recessions of 30 individual events. Solutes sharing the same dominant water sources exhibited similar behavior. Groundwater-sourced solutes exhibited dilution patterns, and their long-term cQ behavior was representative of their cQ behavior during hydrologic events. Other solutes, however, exhibited highly variable cQ behavior from one event to the next, and very different cQ patterns at intra-event and longer-term time scales. This was particularly true for trace metals as well as atmospherically derived and/or biologically active solutes. Most of the observed event-to-event variability in cQ behavior could be explained by factors such as catchment wetness, season, event size, input concentrations, and event-water contributions. These relationships help to clarify how the release of solutes depends on their catchment sources and pathways. Our analysis thus provides insight into controls on solute variations at the hydrologic event scale.