bluuebunny/crossref_metadata_2025 huggingface dataset:
Proposing a typology of nature-based solutions for strengthening resilience of Central Vietnamese cities – First findings from the GreenCityLabHue project
Authors: Scheuer Sebastian , Jache Jessica , Rösler Kora , Tuan Anh Tran , Ngoc Tung Nguyen , Vu Minh Nguyen , Quang Huy Nguyen , Thi Binh Minh Hoang , Konopatzki Patrick , Stolpe Fabian , Sumfleth Luca , Zschiesche Michael , Haase Dagmar
Published: March 2020

Idea and Objectives: This case study presents first findings of the GreenCityLabHue project. The project aims at implementing an urban learning lab in the city of Hue, Vietnam, for the participatory identification and implementation of innovative nature-based solutions for the protection and improvement of urban ecosystem services and climate change adaptation. We will present urgent environmental and societal challenges for the city of Hue, including the estimated impacts of climate change and resulting disaster risks. Subsequently, we will discuss elements of the green-blue infrastructure to tackle these risks in a sustainable and environmentally just manner in the context of a proposed typology of nature-based solutions. This typology specifically shifts the focus from a European perspective towards nature-based solutions that are locally relevant to strengthen the resilience of Hue and comparable cities in Central Vietnam and/or South-East Asia.

Background: Vietnam is a country that faces multiple challenges. It is a country that experiences rapid urban growth, with an estimated 50% of citizens living in urban areas by 2030 up from 35%, resulting in urban expansion that necessitates safeguarding urban ecosystem services, e.g., for the protection of human health and human well-being. Vietnam is also heavily affected by climate change. Particularly in Central Vietnam, cities face increasing risks of flooding, storms, and temperature extremes.

By providing multifunctional ecosystem services and diverse benefits, nature-based solutions—and in particular green-blue infrastructure elements—may help to address the aforementioned environmental and societal challenges in a sustainable and integrative manner, e.g., for maintaining air quality, stormwater mitigation, climate regulation, and improving environmental equity.

Hue is the capital of the Thua Thien-Hue province, located in Central Vietnam on the banks of the Perfume River. It has a population of approximately half a million people, represents a touristic and educational hotspot, and is rated a “top priority city” by the Vietnamese government. In Hue, first steps that consider strengthening the green-blue infrastructure were devised in form of the Hue GrEEEn City Action Plan. However, a more holistic urban planning approach that also addresses challenges related to climate change is still lacking.
Towards impact-based communication during emergencies: Development of site-specific warning services in Catalonia
Authors: Landaverde Erika , Sempere-Torres Daniel , Berenguer Marc
Published: March 2020

Early warning systems are a critical element for flood risk reduction. If properly designed and disseminated, flood warnings can empower citizens and communities at risk by enhancing their preparedness and their response capacity during a flood event to reduce the possibility of personal injury or loss of life. Nevertheless, the reported situations where citizens did not react to warnings keep increasing, regardless if timely warnings were issued in the area. Receiving an official flood warning is not enough to guarantee appropriate proactive responses and self-protective behaviours from citizens during weather-related emergencies.

Flood warnings should aim to communicate clear and relevant local information on how floods might have an impact on citizens and what actions they can do to ensure their safety. Site-Specific Warnings (SSWs) are proposed as a step towards impact-based communication for citizens during weather-related emergencies.  The SSWs aim to translate meteorological and hydrological hazards into location-specific impacts and thus, propose appropriate local self-protection actions using local vulnerability and exposure information.

In this work, a prototype of SSWs has been developed for previously defined vulnerable points in the city of Blanes, Spain. As part of the first stage of implementation, a mobile app has been designed to serve as a risk communication platform during emergencies. The SSW app can inform users in real-time, the current warning level of vulnerable sites in the city on Blanes and the appropriate protective actions to be performed by citizens on each location to minimize consequences. Further components are the capability of users receiving official messages from authorities regarding a site risk level and the possibility of linking the SSW app to tailor-made multi-hazard early warning system platforms for operational authorities.

Finally, by moving towards warnings that can help citizens respond appropriately and effectively during a crisis, SSWs could play a central role in promoting a shift on how societies and authorities currently deal with weather-induced emergencies and their associated impacts.
Strong changes in the relationship between storage and discharge during a period of thawing soils and climate warming in Northern Sweden
Authors: Hinzman Alexa , Sjöberg Ylva , Lyon Steve , Ploum Stefan , van der Velde Ype
Published: March 2020

The Arctic is warming at an unprecedented rate. This warming affects not just ecosystems, but also permafrost, landscape configuration, and water availability in watersheds. One relatively under researched process is how seasonally frozen soils and changes thereof affect the water cycle. As frozen soils thaw, flow pathways within a catchment open, allowing for enhanced hydrologic connectivity between groundwater and rivers. As the connectivity of flow paths increase, the storage-discharge relationship of a watershed changes, which can be perceived within a hydrograph. More specifically, previous studies hypothesized that storage-discharge relationships are relatively linear when soils are frozen and become increasingly non-linear as the landscape thaws.

The objective of our research is to expand on the assumption that soil thaw leads to increasingly non-linear storage-discharge relationships by quantifying trends and spatio-temporal differences of this relationship. We will present our analysis of sixteen watersheds within Northern Sweden throughout the years of 1951 and 2018. We focus on spring and summer storage-discharge relationships and show how they are affected by preceding winter conditions.

We found a clear increase in non-linearity of the storage-discharge relationship over time for all catchments with twelve out of sixteen watersheds (75%) having a statistically significant increase in non-linearity. For twelve watersheds, spring relationships were significantly more linear compared to summer, which supports the hypothesis that seasonally frozen soils have less hydrological connectivity leading to more linear storage-discharge relationships. Winter conditions that allow deep soil frost lead to more linear storage-discharge relationships for ten watersheds. Overall, we show that thawing soil leads to a more non-linear storage-discharge relationship which implies river runoff in the Arctic becomes more unpredictable.
A brisk local uncertainty estimator for hydrologic simulations and predictions (Blue Cat)
Authors: Koutsoyiannis Demetris , Montanari Alberto
Published: March 2020

We propose a brisk method for uncertainty estimation in hydrology which maximizes the probabilistic efficiency of the estimated confidence bands over the whole range of the predicted variables. It is an innovative approach framed within the blueprint we proposed in 2012 for stochastic physically-based modelling of hydrological systems. We present the theoretical foundation which proves that global uncertainty can be estimated with an integrated approach by tallying the empirical joint distribution of predictions and predictands in the calibration phase. We also theoretically prove the capability of the method to correct the bias and to fit heteroscedastic uncertainty for any probability distribution of the modelled variable. The method allows the incorporation of physical understanding of the modelled process along with its sources of uncertainty. We present an application to a toy case to prove the capability of the method to correct the bias and the entire distribution function of the predicting model. We also present a case study of a real world catchment. We prepare open source software to allow reproducibility of the results and replicability to other catchments. We term the new approach with the acronym BLUE CAT: Brisk Local Uncertainty Estimation by Conditioning And Tallying.
Association of chorus waves and source/seed electrons with the enhancement of relativistic electrons in the outer Van Allen belt
Authors: Nasi Afroditi , Daglis Ioannis A. , Katsavrias Christos , Li Wen
Published: March 2020

Local acceleration driven by whistler-mode chorus waves is fundamentally important for the acceleration of seed electrons in the outer radiation belt to relativistic energies. Τhis mechanism strongly depends on substorm activity and on the source electron population injected by the substorms into the inner magnetosphere. In our work we use Van Allen Probes data to investigate the features of source electrons, seed electrons and chorus waves for events of enhancement versus events of depletion of relativistic electrons in the outer Van Allen belt. To that end we calculate the electron phase space density (PSD) for five values of the first adiabatic invariant corresponding to source and seed electrons, and we perform a superposed epoch analysis of 28 geomagnetic disturbance events, out of which, 20 result in enhancement and 8 in depletion of relativistic electron PSD. Our results indicate that events resulting in significant enhancement of relativistic electron PSD in the outer radiation belt are characterized by statistically stronger and more prolonged storm and substorm activity, leading to more efficient injections of source but mostly seed electrons to the inner magnetosphere, and also to more pronounced and long-lasting chorus and Pc5 wave activity. The effect of these parameters in the acceleration of electrons seems to be determined by the abundance of seed electrons at the region of L*=4-5.
Climate of the Reformation: droughts and anomalous weather in the 1500s-1510s in Europe
Authors: Kiss Andrea , Barriendos Mariano , Brázdil Rudolf , Camenisch Chantal , Enzi Silvia , Olinski Piotr , Pribyl Kathleen , Retsö Dag
Published: March 2020

In the 1500s-1510s an unusually high number of significant droughts in Central and Western, and partly in Southern Europe; the years 1502-1504, 1506-1507, 1513-1514 and 1516-1518 were dry particularly in Central and Western Europe. Droughts, interspersed with wet years marked even by significant floods and other weather-related extremes, and frequent hard winters were mainly responsible for the reduced or poor crop and hay harvests in multiple years. These circumstances, in combination with other socio-economic factors, contributed to the increased social tension of the period, manifesting itself in major peasant uprisings, and might have acted as a catalyst in the timing and rapid spread of the Reformation.

The first part of the presentation is concentrated on the reconstruction and spatial-temporal analysis of the droughts (and hard winters) using documentary evidence – in comparison with the tree-ring based hydroclimate reconstruction (OWDA: Cook et al. 2015) and the multiproxy-based reconstruction of Central European precipitation (Pauling et al. 2006).

The most significant groups of socio-economic consequences are analysed in the second part of the presentation, with special emphasis on discussing the possible cumulative effects of the anomalous weather conditions during the period on the ongoing transformation of the late-medieval society and economy and the Reformation itself.
Tritium-Helium Dating of Groundwater in a Fractured and Karstified Carbonate Rock Aquifer
Authors: Osenbrück Karsten , Fünfgeld Freya , Sültenfuss Jürgen , Blackwell Nia , Grathwohl Peter
Published: March 2020

Fractured and karstified aquifers are often vulnerable to pollution by nitrate or other anthropogenic compounds. Therefore, a better understanding of the flow and transport processes in these aquifers is imperative for effective drinking water management. In this study, we used the analysis of tritium and tritiogenic helium-3 concentrations to estimate the residence and exposure time of nitrate transported in a fractured groundwater system of the Upper Muschelkalk in southwest Germany.

The recharge area is characterised by elevated nitrate concentrations of up to 60 mg/L which are in accordance with dominating agricultural landuse in the catchment. Further along the groundwater flow direction a significant decrease in dissolved oxygen as well as nitrate concentrations to values close to the detection limit is observed.

Tritium/3He ages were found to be in the range of zero to forty years. However, in the fractured aquifer the age tracers were most probably affected by mixing and exchange processes that might change the concentration as well as the ratio of tritium and helium-3 in addition to radioactive decay. Therefore, we investigated the impact of different transport processes such as mixing of water parcels at fracture joints or exchange between mobile water on fractures and the pore matrix using forward convolution approaches for both isotopes separately.

In combination with hydrochemical, multi-isotopic, petrographical, and molecular biological data, the groundwater residence time data was intended to gain crucial insight into the processes and limiting factors of autotrophic denitrification found within the Muschelkalk aquifer.
The fast evolution of the Tazones Lighthouse landslide (N Spain): multidisciplinary 3D monitoring between 2018 and 2019
Authors: Domínguez-Cuesta María José , González-Pumariega Pelayo , Valenzuela Pablo , López-Fernández Carlos , Herrera Fernando , Mora Manuel , Meléndez Mónica , Marigil Miguel Ángel , Espadas Carlos , Cuervas-Mons José , Pando Luis , Jiménez-Sánchez Montserrat
Published: March 2020

The Tazones Lighthouse landslide is an active mass movement affecting a stretch of the Cantabrian Coast (N Spain), characterized by the presence of almost vertical rocky cliffs developed on Jurassic rocks. The area is being monitored since 2018 when irreversible structural damages appeared in a building located in the surroundings of the lighthouse because of the fast evolution of the landslide.

 

On June 2018, the first 24 topographic marks were installed by the COSINES Project researchers and 10 more were set up on December of that year, after the appearance of new cracks. Since then, monthly monitoring campaigns have been carried out by total station to gauge the displacement of the 34 mentioned marks and 4 additional control points. One of the control marks was lost, between January and February 2019, due to the fast evolution of the movement. Monitoring has been complemented by the elaboration of detailed digital terrain models through drone flights carried out in November 2018 and November 2019. In addition, precipitation data registered on the rainfall gauges of the surroundings have been collected.

 

This contribution presents the recent fast evolution of the Tazones Lighthouse landslide, affecting an area about 70.000 m2 and characterized by relevant horizontal and vertical displacements. Since the beginning of the 3D monitoring, the 50% of the marks have moved more than 1 meter and 34% of them have moved more than 2 meters, one of them exceeding 14 meters of displacement.

The detailed digital terrain models have allowed quantifying the volume of mobilized mass over a year from the main head of the movement, located 110 meters above sea level. Moreover, the comparison of these data with precipitation records has led to relate the evolution of the displacement with the rainfall, being able to establish a very good correlation between precipitation distribution and movement acceleration.
Democratizing ocean technology: low-cost innovations in underwater robotics
Authors: Chua Allison , MacNeill Aaron , Wallace Douglas
Published: March 2020

In comparison to the ocean’s immense volume and diversity of research areas, the number of sensors required to make the majority of desired measurements is quite small. This inequality of supply and demand elevates prices, adding further barriers for developing nations or fledgling research programs with smaller budgets attempting ocean science. Our work aims to demonstrate the potential of combining commercially available, open-source products to create inexpensive, configurable, and user-friendly platforms that can be adapted for underwater navigation and integration with most commercial oceanographic sensors.

Specifically, we will highlight modifications made to a Blue Robotics BlueROV2, which we have configured for various missions including vertical profiling of a coastal fjord and three-dimensional mapping of crude oil spills. The BlueROV2 offers an easily modified platform for physical mounting of sensors and streaming of sensor data via its onboard computer, a Raspberry Pi. Our custom circuit board is “sensor-agnostic”, powering sensors from a common source (the ROV battery) and using an Arduino that accepts analog or digital sensor inputs, allowing us to choose from a wide range of sensors. Physical modifications make use of inexpensive, readily available materials, and range from simple plastic brackets for small sensors to a skid for a sensor with half the ROV’s original weight, which utilizes pop bottles for buoyancy.

While products such as Pixhawk, Raspberry Pi, Arduino, and BlueROV have inspired hobbyists and youth around the world, they paradoxically have not been as widely embraced in the academic community, who perhaps remain unaware of their research potential. Thus, while there has yet to be an analogous push to develop inexpensive, small, power-efficient, and open-source sensors, these platforms offer exciting opportunities to build a new generation of oceanographic tools with measurement abilities far exceeding those of their predecessors. We are at an ocean technology tipping point, and, as MacGyver says, “With a little bit of imagination, anything is possible.”
Impact of climate change in Mediterranean river basins: relation between droughts, vegetation and reduction of waterdischarge
Authors: Labrousse Camille , Ludwig Wolfgang , Lacquement Guillaume , Sadaoui Mahrez
Published: March 2020

Abstract:

The Languedoc-Roussillon region is a Mediterranean area located Southern France and composed of 6 main coastal river catchments about 1000 to 4800 km2 each and discharging to the Gulf of Lion. A first study investigating evidences of climatic changes in the river basins showed a significant reduction of the waterdischarge of 20 % in average in the whole area during the period 1965-2004 (40 years).By including the most recent years (up to 2018), the time series demonstrate that the decline in water discharge still continues and could consequently have been reduced by more than 40% since the years 1960. Thus, understanding the relation and effect of climatic changes on hydrology is essential for the development of water resource strategies.

In this study, we examine and analyse the long-term dynamics of the drought indices as climatic parameters and the impact of their changes on the 6 coastal river waterdischarge at the annual and seasonal scales. ­­­We investigate the meteorological, and agricultural droughts as well as the vegetation density’s evolution through time and compute statistical analysis to understand the linkage with the reduction of waterdischarge. First results show a trend toward dryer years as well as a strong correlation between mean annual hydrological variations and drought indices.
Automatic classification of seismo-volcanic signals at La Soufrière of Guadeloupe
Authors: Falcin Alexis , Metaxian Jean-Philippe , Mars Jérôme , Stutzmann Eléonore , Moretti Roberto , Komorowski Jean-Christophe
Published: March 2020

Seismic activity at La Soufrière volcano of Guadeloupe is composed of various transient signals, which are classified manually by the Observatoire Volcanologique et Sismologique de Guadeloupe (OVSG-IPGP) considering waveforms recorded at several stations. Although five main types of signals are recognized in the data analysis by the observatory (Moretti et al., 2020), only three main classes readily distinguishable on seismic traces during the daily analytical protocol have been catalogued: Volcano-Tectonic events, Long-Period events and Nested events, each related to a distinct physical process.

Automatic classification of seismo-volcanic signals of La Soufrière was performed by using an architecture based on supervised learning, available at github.com/malfante/AAA. Seismic waveforms are transformed into a large set of features (34 features for each representation domain) computed from three representation domain of the signal (time, frequency, quefrency). The resulting vectors of features are then used for the modeling. We are using the Random Forest Classifier algorithm from the scikit-learn library.

At first, we trained the model with the dataset given by the OVSG consisting of 845 available labeled events (542 VT, 217 nested and 86 LP) recorded in the period 2013-2018. We obtained an average classification rate of 72 %. We determined that the VT class includes a variety of signals covering the LP, Nested and VT classes. Reviewing in details the waveforms and the spectral characteristics of the signals belonging to the 3 classes we then introduced Hybrid events and also defined a monochromatic class (so-called Tornillo) of LP signals, thus matching the full description of signals provided in Moretti et al. (2020).

Then, using the new information, a new model was trained with 5 classes and tested. We obtained a much better classification average rate of 84 %. The classification is excellent for Nested events (93 % of accuracy and precision) and Tornillo events (93% of accuracy and precision). The classification of VT events (90% accuracy, 89% precision) and LP events (86% accuracy, 82% precision) were also very good. The most difficult class to recognize is the Hybrid class (64 % accuracy, 69 % precision). Hybrid events are often mixed with VT and LP events. This may be explained by the nature of this class and the physical process that includes both a fracturing and a resonating component with different modal frequencies.

Machine learning is a powerful tool to handle large datasets. From a dataset built manually, the processing we applied allowed to obtain a reliable automatic classification by refining class definitions. This has important implications for observatory data processing during unrest and eruptive activity.
Decadal Variability of Precipitation Extremes over India
Authors: Mandraha Shivanand , Ray Sujata
Published: March 2020

The occurrence of extreme precipitation events is a severe concern to any nation due to its socio-economic impacts. In this study, spatiotemporal variability of precipitation extremes was analyzed over the Indian sub-continent using the quantile perturbation method (QPM). QPM is a non-parametric method that requires very few assumptions. The gridded data of precipitation with 0.5 × 0.5-degree resolution CRU (Climate Research Unit, University of East Anglia, UK) and 117 years (1901-2017) data set has been used. The result shows that the initial decade (1910s to 1940s) and the recent decade (1990s to 2000s) are the decades when significant anomalies found in most of India. The northeast part of India shows positive anomalies while the central region and northern region show negative anomalies in the 1910s. In the period of 1930-1940s central India shows positive anomalies, and the northern region shows negative anomalies. Significant positive anomalies found in the west part of southern India in the period of 1950-1960s. In the period of 1960-2000s, the northern region shows positive anomalies. Indo-Gangetic plain and central India have negative anomalies while the western part shows positive anomalies in the 2000s in most of the grid. To partially address the reason behind the perturbation correlation analysis has been applied between extreme precipitation anomaly and Indian Ocean Dipole. Results show a moderately negative correlation found in most of the eastern and north-eastern regions of India, while a positive correlation found in some northern and southern parts of India. Analysis suggests that Indian Ocean sea surface temperature might be the main driver for the decadal perturbations in precipitation extremes.
The Role of Gases in an Arsenic Contaminated Aquifer
Authors: Lightfoot Alexandra , Brennwald Matthias , Kipfer Rolf
Published: March 2020

Arsenic (As) contamination of groundwater remains a problem for many of the river deltaic areas in South-East Asia; where concentrations regularly exceed the 10μ/L currently recommended by the Word Health Organization. The focus of this study, is to determine noble and reactive gases in groundwaters at a location where As mobilisation is active, to constrain the sites hydrology in such a highly reducing environment. The small village of Van Phuc, Vietnam, presents an ideal opportunity for such research as is it well studied and accessible, however As dynamics here are still not well understood.

Gas concentrations in 21 wells at varying depths and locations were analysed in Van Phuc with the miniRUEDI, a portable mass spectrometer capable of measuring noble gases: He, Ar, Kr, and reactive gases: CO2, CH4, N2 and O2. Water samples were additionally taken in copper tubes for later analysis, in an effort to date the groundwater using the 3He ingrowth method. Dating such samples is particularly difficult in environments such as Van Phuc, where Methane tends to oversaturate and foster in-situ degassing of the groundwater.

First results show a progressive depletion of the atmospheric gases (Ar, Kr and N2) with increasing CH4 concentrations. He, shows the opposite behaviour such that it increases in concentration as CH4 approaches in-situ saturation within the groundwater. The conceptual picture these results indicate, is that the production of Methane bubbles reduces the hydraulic conductivity in the aquifer; allowing enough time for He to accumulate, whilst simultaneously depleting Ar, Kr and N2 in the groundwater as a result of their partitioning into the free CH4 gas phase, which is subsequently degassed.
The importance of lithology and throw rate on bedrock river behaviour and evolution in the Gediz (Alaşehir) Graben, Turkey.
Authors: Boulton Sarah , Whittaker Alexander , Kent Emiko , Alcicek M. Cihat , Fabel Derek
Published: March 2020

The Gediz (Alaşehir) Graben is located in the highly tectonically active and seismogenic region of Western Turkey, which has been experiencing high-angle normal faulting since ~ 2 Ma.  Rivers upstream of the normal fault-bounded graben each contain a lithologic knickpoint related to the change in bedrock geology (from soft sediments to hard metamorphic rocks) and a non-lithologic knickpoint, caused by an increase in fault slip rate at ~ 0.8 Ma.  Therefore, this system represents an ideal natural laboratory to investigate the relative roles of bedrock lithology / rock strength and rates of faulting on the behaviour and evolution of bedrock river systems. Our results show that metamorphic rocks in the catchments are 2-3 times harder than the sedimentary rocks. Stream power increases downstream reaching local maxima upstream of the fault within the metamorphic bedrock but declines rapidly once softer sedimentary rocks are encountered. We also demonstrate a positive correlation between throw rate and stream power in the metamorphic rocks characteristic of rivers obeying a detachment-limited model of erosion. In sedimentary rocks stream powers are invariant with throw rate but do scale with the river’s sediment transport capacity. We also present new Be10 denudation rates that show correlations with calculated stream power and fault throw rates. This study demonstrates that the strength of underlying bedrock is a major influence on river evolution and that the nature of the underlying lithology profoundly influences the way in which the river behaves.
Sedimentary evolution of a bedrock-conditioned incised valley since the Last Glacial Maximum: the Ría de Arousa (NW Spain)
Authors: Cartelle Víctor , García-Gil Soledad , García-Moreiras Iria , Muñoz-Sobrino Castor , Martínez-Carreño Natalia
Published: March 2020

Coastal sedimentary environments are dynamic systems in continuous change responding to different temporal and spatial scales. Their sedimentary record offers invaluable data to unveil the effect of different drivers, such as relative sea-level rise, on their evolution.

The Ría de Arousa is located on the Atlantic coast of Galicia (NW Spain) and represents the largest of the so-called “Galician Rias”, with a total area of 230 km2. It corresponds to a mesotidal tide-dominated incised valley characterized by a complex physiography with numerous smaller bays, islands and peninsulas.

The identification of elements of sedimentary architecture was used to study the sedimentary evolution of this incised valley since the Last Glacial Maximum (ca 20 kyr BP to present). This approach was based on the combined analysis of seismic and sedimentary facies, complemented with radiocarbon, geochemical and pollen data.

During the lowstand of the Last Glacial Maximum, a river basin occupied the deep axial valley whose physiography was controlled by the rocky basement morphology and the presence of preserved older sedimentary units. The postglacial transgression changed the base level of rivers, flooding the valley and leading to the formation of an estuary. Facies distribution during this phase (Late Pleistocene) was characterized by large tidal sandbanks and sandflats in the outer area and a bayhead delta at the river mouths. As the transgression proceeded, during the Early Holocene, the system evolved into a tide-dominated estuary. Tidal sandbanks and sandflats occupied large extensions in the axis of the valley, flanked by mudflats. The presence of a small group of islands in the middle area of the incised valley gave way to the existence of an ancient strait during most of the postglacial transgression (Late Pleistocene and Holocene), modulating the relative influence of hydrodynamic conditions and probably leading to tidal currents amplification due to the local morphological narrowing. These structural highs favored the formation of a rock-bounded tidal inlet in the middle of the valley, characterized by scarce deposition and erosional processes.

During the Middle and the Late Holocene, most of the incised valley became drowned, and wave influence increased. A wave ravinement surface is identified, which was developed around 8 cal kyr BP coeval with the initiation of large storm fans associated with rocky barriers.

Finally, a maximum flooding surface is recognized at ca 5 cal kyr BP while the slow rise of sea level forced river mouths to retreat to its present position and marine processes became dominant in the basin.
PoPEx - An adaptative importance sampler for the categorical inverse problem
Authors: Renard Philippe , Jäggli Christoph , Dagasan Yasin , Juda Przemyslaw , Straubhaar Julien
Published: March 2020

One challenge in stochastic hydrogeological modeling is to solve the inverse problem when the parameter fields take a discrete set of values. This typically occurs when considering different rock types having a large contrast in parameter values. Situations of this kind are particulary hard because the usual techniques based on derivatives (sensitivity coefficients) or covariances are inefficient. In this presentation, we will present the Posterior Population Expansion (PoPEx) method. It is an ensemble based technique designed to identify categorical parameter fields in a Bayesian perspective. The method generates iteratively an ensemble of categorical fields using any geostatistical technique and evaluates their likelihood values.To illustrate the method, we will employ a multiple-points statistic technique, but the approach is general. During the inversion process, the relation between observed state variables and parameter values is derived from the ensemble and used to constrain the generation of the next categorical fields. The method is shown to be more efficient than more classical Markov chain Monte Carlo approaches and to provide accurate uncertainty estimates on a set of examples. As the algorithm still requires to compute the likelihood for a significant number of fields, we also explore how Generative Adversarial Networks could be used to accelerate PoPEx by predicting rapidly the misfit.
Comparing Assimilation of Soil Moisture and C-band Backscatter in High Resolution Land Surface Model
Authors: Sun Leqiang , Belair Stéphane , Carrera Marco , Bilodeau Bernard
Published: March 2020

Canadian Space Agency (CSA) has recently started receiving and processing the images from the recently launched C-band RADARSAT Constellation Mission (RCM). The backscatter and soil moisture retrievals products from the previously launched RADARSAT-2 agree well with both in-situ measurements and surface soil moisture modeled with land surface model Soil, Vegetation, and Snow (SVS). RCM will provide those products at an even better spatial coverage and temporal resolution. In preparation of the potential operational application of RCM products in Canadian Meteorological Center (CMC), this paper presents the scenarios of assimilating either soil moisture retrieval or outright backscatter signal in a 100-meter resolution version of the Canadian Land Data Assimilation System (CaLDAS) on field scale with time interval of three hours. The soil moisture retrieval map was synthesized by extrapolating the regression relationship between in-situ measurements and open loop model output based on soil texture lookup table. Based on this, the backscatter map was then generated with the surface roughness retrieved from RADARSAT-2 images using a modified Integral Equation Model (IEM) model. Bias correction was applied to the Ensemble Kalman filter (EnKF) to mitigate the impact of nonlinear errors introduced by multi-sourced perturbations. Initial results show that the assimilation of backscatter is as effective as assimilating soil moisture retrievals. Compared to open loop, both can improve the analysis of surface moisture, particularly in terms of reducing bias.  
From soil degradation to restoration via soil microorganisms
Authors: Coban Oksana , de Deyn Gerlinde , van der Ploeg Martine
Published: March 2020

Soil, the living skin of the Earth, provides ecosystem services critical for life: soil acts as a water filter and a growing medium, offers habitat for billions of organisms, and supplies most of the antibiotics. In places, it may take a hundred years to form one cm of soil, but it can be degraded only in a few years or less by a number of natural and anthropogenic factors, including climate change. Presently, one third of all land is degraded to some extent, and fertile soil is lost every year. Droughts are becoming more common, also in humid climates, and the combination of erratic weather patterns with an increased pressure on land by human activities leads to soil degradation. Soil degradation results in a loss of fertile topsoil, thereby altering the soil hydrology completely. As the consequences, soil water holding capacity decreases, hydrophobicity increases, and more runoff is observed, that leads to further soil degradation. Thus, soil hydrology is the key for a healthy functioning topsoil/soil ecosystem. We are in urgent need for novel solutions for improving soil hydraulic properties that will lead to restoration of degraded soils.

In this study we investigate a possibility of restoring degraded soil using microorganisms. The hypothesis is that microorganisms can improve soil hydraulic properties such as infiltration and water retention, and reduce hydrophobicity that will facilitate further ecosystem restoration. Such strategy is based on combining the research fields of microbiology and soil physics that to date have hardly been combined. To test this hypothesis, we have inoculated sandy soil with a bacterium Bacillus mycoides and then measured its hydraulic properties using evaporation and pressure plate methods. We have also made efforts of standardizing this methodology by testing incubation time and inoculum concentrations on the hydraulic properties of the soil. Evaluation of an effect of bacteria addition on the soil water holding capacities and unsaturated water conductivity have been conducted as a comparison between inoculated soil and uninoculated (control). Results of this ongoing study will be presented here.
Effective Radiative Forcing and Adjustments in CMIP6
Authors: Smith Christopher , Kramer Ryan , Myhre Gunnar , Alterskjær Kari , Collins Bill , Pincus Robert , Forster Piers ,   RFMIP modelling groups
Published: March 2020

The effective radiative forcing, which includes the instantaneous forcing plus adjustments from the atmsophere and surface, as emerged as the key metric of evaluating human and natural influence on the climate. We evaluate effective radiative forcing and atmospheric adjustments in 13 contemporary climate models that are participating in CMIP6 and have contributed to the Radiative Forcing Model Intercomparison Project (RFMIP). Present-day (2014) global mean anthropogenic forcing relative to pre-industrial (1850) from climate models stands at 1.97 (± 0.26) W m-2, comprised of 1.80 (± 0.11) W m-2 from CO2, 1.07 (± 0.21) W m-2 from other well-mixed greenhouse gases, -1.04 (± 0.23) W m-2 from aerosols and -0.08 (± 0.14) W m-2 from land use change. Quoted ranges are one standard deviation across model best estimates, and 90% confidence in the reported forcings, due to internal variability, is typically within 0.1 W m-2. The majority of the remaining 0.17 W m-2 is likely to be from ozone. As determined in previous studies, cancellation of tropospheric and surface adjustments means that the "traditional" stratospherically adjusted radiative forcing is approximately equal to ERF for greenhouse gas forcing, but not for aerosols, and consequentially, not for the anthropogenic total forcing. The spread of present-day aerosol forcing has narrowed compared to CMIP5 models to the range of -0.63 to -1.37 W m-2, with a less negative mean. The spread in CO2 forcing has also narrowed in CMIP6 compared to CMIP5, which may be a consequence of improving radiative transfer parameterisations. We also find that present-day aerosol forcing is uncorrelated with equilibrium climate sensitivity. Therefore, there is no evidence to suggest that the higher climate sensitivity in many CMIP6 models is a consequence of stronger negative present-day aerosol forcing.
Model intercomparison of idealized global deforestation experiments
Authors: Brovkin Victor , Boysen Lena , Pongratz Julia , Vuichard Nicolas , Peylin Philippe , Lawrence David
Published: March 2020

We present first results of idealized deforestation experiment designed within the Land Use Model Intercomparison Project (LUMIP). In order to obtain a robust signal-to-noise ratio and to harmonize deforestation implementation across participating ESMs, global forest extent is linearly decreased by 20 million km2 for the 30% of most forested grid cells over a period of 50 years starting from pre-industrial climate conditions. This experimental setup is in favor of predominantly tropical deforestation patterns, however, there is also substantial boreal deforestation. In this experiment, atmospheric and oceanic physical processes respond to large-scale deforestation while other forcings such as atmospheric CO2 concentration and aerosol load are kept constant at the pre-industrial level.

First analysis of results from ESMs participating in the LUMIP experiments reveal a general cooling trend in response to deforestation, although a spread in an amplitude of response is substantial. In boreal region there is significant cooling effect, presumably due to an increase in surface albedo, while tropical deforestation results in a regional warming in most of models. A sensitivity of temperature change per forest fraction change on a grid cell level, ∂T/∂F, likely could be used as a generic response for any forest change scenario, although it is complicated by mixing together local and non-local effects. We also quantified so-called “zero effect latitude” at which forest cover change does not have pronounced biogeophysical effect. It is located in northern subtropics in most models.

Analyses of ensemble-members of three models (MPI-ESM1.2-LR, IPSL-CM6A-LR, and CESM2) indicate that the “time of emergence” of climate response, when signal becomes larger than a noise, is quite different among the models. However, when we compare the “deforested fraction of emergence”, the model responses become much more coherent. Biomass and soil carbon storages are decreasing with time, and their “time of emergence” is much shorter comparing to the temperature and precipitation. More results of biogeophysical and biogeochemical responses to deforestation will be presented.
EMODnet Bathymetry – further developing a high resolution digital bathymetry for European seas
Authors: Schaap Dick M. A. , Schmitt Thierry
Published: March 2020

Access to marine data is a key issue for the EU Marine Strategy Framework Directive and the EU Marine Knowledge 2020 agenda and includes the European Marine Observation and Data Network (EMODnet) initiative. EMODnet aims at assembling European marine data, data products and metadata from diverse sources in a uniform way.

The EMODnet Bathymetry project is active since 2008 and has developed Digital Terrain Models (DTM) for the European seas, which are published at a regular interval, each time improving quality and precision, and expanding functionalities for viewing, using, and downloading. The DTMs are produced from survey and aggregated data sets that are referenced with metadata adopting the SeaDataNet Catalogue services. SeaDataNet is a network of major oceanographic data centres around the European seas that manage, operate and further develop a pan-European infrastructure for marine and ocean data management. The latest EMODnet Bathymetry DTM release also includes Satellite Derived Bathymetry and has a grid resolution of 1/16 arcminute (circa 125 meters), covering all European sea regions. Use has been made of circa 9400 gathered survey datasets, composite DTMs and SDB bathymetry. Catalogues and the EMODnet DTM are published at the dedicated EMODnet Bathymetry portal including a versatile DTM viewing and downloading service.  

As part of the expansion and innovation, more focus has been directed towards bathymetry for near coastal waters and coastal zones. And Satellite Derived Bathymetry data have been produced and included to fill gaps in coverage of the coastal zones. The Bathymetry Viewing and Download service has been upgraded to provide a multi-resolution map and including versatile 3D viewing. Moreover, best-estimates have been determined of the European coastline for a range of tidal levels (HAT, MHW, MSL, Chart Datum, LAT), thereby making use of a tidal model for Europe. In addition, a Quality Index layer has been formulated with indicators derived from the source data and which can be queried in the The Bathymetry Viewing and Download service. Finally, extra functonality has been added to the mechanism for downloading DTM tiles in various formats and special high-resolution DTMs for interesting areas.  

This results in many users visiting the portal, browsing the DTM Viewer, downloading the DTM tiles and making use of the OGC Web services for using the EMODnet Bathymetry in their applications.

The presentation will highlight key details of the EMODnet Bathymetry DTM production process and the Bathymetry portal with its extensive functionality.
Reducing urban new particle formation as a plausible solution to mitigate particulate air pollution in Beijing and other Chinese megacities
Authors: Kulmala Markku , Dada Lubna , Bianchi Federico , Yan Chao ,   Aerosol and Haze Laboratory Team
Published: March 2020

With multi- and interdisciplinary approaches we show that atmospheric secondary particles are the dominating contributor to haze formation in terms of aerosol number, surface area and mass. Supported by our comprehensive observations in Beijing during 15 January 2018– 15 January 2020, we show that 80–90% of the aerosol mass (PM2.5) was formed via atmospheric reactions during the haze days and over 65% of the number concentration of haze particles resulted from urban new particle formation (NPF). Furthermore, the haze formation was much faster when the subsequent growth of newly formed particles was enhanced (rapid growth). We found that since the direct emissions of primary particles in Beijing has gone down significantly within recent years, all present-day haze episodes we preceded by a urban NPF event. We are also able to show that reducing the subsequent growth of freshly formed particles by a factor of 3-5 would delay the buildup of haze episodes by 1–3 days. Actually, this delay will decrease the length of each haze episode and the number of annual haze days could be approximately halved. The improvement can be achieved with targeted reduction of NPF precursors, mainly dimethyl amine, ammonia and further reductions of SO2 emissions. Furthermore, reduction of anthropogenic VOC and nitrate emissions will slow down the growth rate of newly-formed particles and consequently reduce the haze formation. Our results show that the presence of haze decreases both boundary layer height and urban heat island intensity, which will further enhance haze particle number and mass concentrations over large spatial scales.

 
MicroPulse DIAL (MPD) ground-based network for Thermodynamic Profiling in the Lower Troposphere
Authors: Spuler Scott , Stillwell Robert , Hayman Matt , Weckwerth Tammy , Repasky Kevin
Published: March 2020

The National Center for Atmospheric Research and Montana State University have developed a 5-unit ground-based test network of MicroPulse Differential Absorption Lidar (MPD) instruments to continuously measure high-vertical-resolution water vapor profiles in the lower atmosphere. These diode-laser-based instruments are accurate, low-cost, operate unattended, do not require external calibration, and eye-safe – all key features to enable larger 'national-scale' networks needed to characterize atmospheric moisture variability, which influences important processes related to weather and climate.  Enhancements to the water vapor MPD architecture have been recently developed that enable quantitative aerosol measurements and atmospheric temperature profiling by simultaneously measuring O2 absorption and aerosol backscatter ratio. This combination of measurements allows for the first DIAL measurements of atmospheric temperature with useful accuracy. The MPD has been demonstrated to provide continuous, range-resolved measurements of atmospheric thermodynamic variables, water vapor and temperature, and quantitative measurements of aerosol scattering from a high spectral resolution (HSRL) channel.  Thus, a network of these instruments shows promise to provide atmospheric profiling capabilities needed by both the climate and weather forecasting research communities.