bluuebunny/crossref_metadata_2025 huggingface dataset:
Tsunamigenesis Revisited
Authors: Moore James , Hubbard Judith , Felix Raquel , Lythgoe Karen , Switzer Adam
Published: March 2020

When modelling tsunamis and assessing tsunami hazard, it is frequently necessary to make simplifying assumptions in order to reduce the problem to one which is computationally tractable within a reasonable period of time. In this paper, we examine the key factors controlling the generation of the initial sea surface wave and present a series of clear and simple guidelines for real-world problems. We also provide number of computational resources (a tsunami loader) which may be utilised with existing tsunami propagation codes (e.g. COMCOT) to modify the initial sea-surface way, where necessary.

 

Most tsunami modelling codes operate under the assumption that the initial sea surface wave is identical to the seafloor perturbation. Yet this is only true for large tsunami sources (Kajiura 1963). With our tsunami loader we model the tsunamigensis process and the formation of the initial sea-surface wave. Critically, the diffusive effect of the water column above the deforming seafloor is accurately addressed, which can result in a substantial decrease in the energy in the initial sea-surface wave.

 

For example, let us consider a rectangular uplifting patch on the seafloor, at a depth of 4km. For a 4x4km square patch, the diffusive effect will result in an energy reduction of 90%. Even if one of those dimensions is 100 times larger, such that we have a relatively large 400x4 km uplifting region, the energy reduction is still 70%. We find the shortest dimension of the uplifting patch provides a strong control on the energy of the initial sea-surface wave, and consequential tsunami. If we move to a 40x40 km square patch we find the reduction is now 20%, and 400x40 km patch is now a relatively modest, but non-negligible 12%.

 

We also include other effects such as the time-dependence of seafloor deformation, which also reduces the potential tsunami energy, and horizontal advection of topography, which conversely increases the potential tsunami energy, in our analysis of the tsunamigenesis process. Currently implemented for fault sources, we are working to include landslide and volcanic sources.
Extraction of Rural Building Damage due to Earthquake using Remote Sensing Imagery
Authors: Li Shaodan , Tang Hong
Published: March 2020

In all kinds of natural disasters, earthquake is regarded as one of the greatest natural disaster in the world, and it seriously threats human's lives and properties. In the actual scene of earthquake disasters, the types of pre-earthquake satellite images available in the affected area are various, and they are from different sensors. However, the current researches on multi-source satellite image building recognition are not sufficient. In addition, when extracting building damage information, we can only determine whether the building is collapsed using the post-earthquake satellite images. Even the images have the sub-meter resolution, the identification of lightly damaged buildings is still a challenge. In order to solve the above problems, in this paper, we will use the post-earthquake UAV images and the pre-earthquake satellite images to extract the building damage information in rural areas of Sichuan, China. In particular, the main research contents of this paper are as follows:

(1) According to the color feature of UAV images and the shape feature from point cloud data, we divide the building damage into four types: intact buildings, slightly damaged buildings, partially collapsed buildings and completely collapsed buildings, and give the rules of damage grades. In particular, the Chinese restaurant franchise model, which simultaneously fuses the color and shape features, is proposed to detect the earthquake-triggered roof-holes. Based on the roof-holes, the type of slightly damaged buildings is identificated.

(2) At present, the model of building extraction from remote sensing images is suitable for an image, that is, for different images, the model needs to learn its model parameters again. In this paper, based on the generalized Chinese restaurant franchise (gCRF) model, we introduce the morphological profiles to propose the gCRF_MBI model. In the residential regions, the buildings are extracted by fusing the spatial information and the morphological profiles in the gCRF_MBI model.

(3) The visual attention model selects the regions of interest from the complex scenes by simulating the visual attention mechanism of biological objects, which is similar to the extraction of residential regions from remote sensing images. In this paper, based on the basic principle of the spectral residual approach, we utilize the approach to extract the latent residential regions from remote sensing images, and we analyze the effects of different band combinations and different threshold methods on the extraction of residential regions.
Trace metal and nutrient fluxes into Arctic ocean by largest Siberian rivers (ArcticFlux)
Authors: Efimov Vasilii , Chalov Sergey , Magritsky Dmitry , Tsyplenkov Anatolii , Efimova Liudmila , Kasimov Nikolay
Published: March 2020

Trace metal and nutrient fluxes into Arctic ocean by largest Siberian rivers (ArcticFlux)

Precise estimates of river runoff are one the most challenging fields of river hydrology. Quantitative assessment of the fluxes of suspended and, especially, bed load, as well as their correlation with the flow dissolved loads remains weekly studied with a crucial need of in-situ observations, especially in large rivers.

The project is focused on semi-empirical and modeling study of flows, concentrations, modes and loads of trace metals and nutrients fluxes of the major rivers of Arctic. Monitoring stations were organized at the outlets of largest Siberian rivers: Ob, Yenisei, Lena, Kolyma, which transport more than 60 % of the water flow from the Russian Arctic. Observations were made for high and low water regime periods on the regular basis, and the total number of samples today exceeds 210. For each sample analyses were made for trace metals (68 elements), nutrients and dissolved and suspended organic carbon matter content both in dissolved and particulate (suspended and bed loads) forms. These samples can determine annual and seasonal distribution to 70% of the chemical elements and substances, carried by large rivers of the Russian Arctic into the Arctic Ocean.

For more accurate flux assessment, a new sampling technique was used. It allows to determine all components of the dissolved, suspended and, especially, bed load along the river section and includes sampling at 3-5 verticals on different depth. As a result, it is possible to determine the variability of the fluxes along the width of the section. As an example, concentrations of suspended sediments on the left and right banks of the Kolyma River differ in 6-7 times (up to70 mg / dm3) and there are significant differences in Ni, Fe, Al, Cu, and Pb fluxes. Heterogeneity in the distribution of sediment and chemical flow across the width of the rivers arise due to the inflow of tributaries and as a result of permafrost melting and wave erosion of the banks. The study of the intensity of bank erosion and sedimentation at the outlets of Arctic rivers both in the field and according to remote sensing data is a significant part of the project. Based on the modeling techniques and application of erosion models for all four Arctic catchments it will also focus on the novel quantitative assessment of bank and catchment erosion contribution into chemical and sediment loads.

The project concept is considered as a part of Marine component of Pan-Eurasian program (PEEX) and builds a bridge to integrate PEEX marine components with the existing terrestrial/atmospheric PEEX

The reported study was funded by RFBR according to the research project 18-05-60219
Social tipping dynamics for stabilizing Earth’s climate by 2050
Authors: Otto Ilona M. , Donges Jonathan
Published: March 2020

Safely achieving the goals of the Paris Climate Agreement requires a world-wide transformation to carbon-neutral societies within the next 30 years. Accelerated technological progress and policy implementations are required to deliver emissions reductions at rates sufficiently fast to avoid crossing dangerous tipping points in the Earth’s climate system. Here, we discuss and evaluate the potential of social tipping interventions (STIs) that can activate contagious processes of rapidly spreading technologies, behaviors, social norms and structural reorganization within their functional domains that we refer to as social tipping elements (STEs). STEs are subdomains of the planetary socio-economic system where the required disruptive change may take place and lead to a sufficiently fast reduction in anthropogenic greenhouse gas emissions. The results are based on online expert elicitation, a subsequent expert workshop, and a literature review. The social tipping interventions that could trigger the tipping of STE subsystems include (i) removing fossil fuel subsidies and incentivizing decentralized energy generation (STE1: energy production and storage systems), (ii) building carbon-neutral cities (STE2: human settlements), (iii) divesting from assets linked to fossil fuels (STE3: financial markets), (iv) revealing the moral implications of fossil fuels (STE4: norms and value systems), (v) strengthening climate education and engagement (STE5: education system) and (vi) disclosing information on greenhouse gas emissions (STE6: information feedbacks). Our research reveals important areas of focus for larger-scale empirical and modeling efforts to better understand the potentials of harnessing social tipping dynamics for climate change mitigation.
Advanced mobile-DOAS techniuqes for locating and identifying urban area emission sources
Authors: Hu Zhaokun , Li Ang , Xie Pinhua
Published: March 2020

Pollutant concentration distribution and emission are important ways to understand regional pollution. To investigate the distribution characteristics and identify individual sources rapidly, a new mobile passive differential optical absorption spectroscopy (DOAS) instrument has been developed, which set two angle telescopes (90°,30°) to receive the scattered light respectively, and set two mechanical shutters to switch the optical path quickly in the mobile platform. The instrument collected the zenith scattered light in the UV or visible region and it was used to derive the vertical column density of trace gases above the measurement route. The slant column density in two different viewing directions were detected, and combined with the geometric approximation, the vertical column density of trace gas was obtained. After obtaining the column concentration distribution, the data were analyzed by semi variance analysis combined with geographical information. Monte Carlo simulation was used to reconstruct the high spatial resolution pollutant concentration distribution, combined the wind field data during the observation, the high spatial resolution emission flux in the area can be quickly obtained. A field experiment was performed in Beijing and some industrial area. The distribution information of vertical column density along the route in Beijing was derived, the concentration distribution of NO2 at 200m *200m resolution and the 0.01° *0.01°resolution emission flux data are obtained further. The new mobile multi light DOAS instrument were operated on a car. The NO2 column density spatial distribution and the emission flux spatial distribution are obtained with the maximum value of 8.57×1016 molec./cm2 and 34.8 ug/m2/s over the Beijing fifth ring road area. The scheme can provide a new method to verify pollutant concentration distribution and emission inventory.
Spatial variations of stochastic noise properties of GNSS time series
Authors: Fernandes Rui , He Xiaoxing , Montillet Jean-Philippe , Bos Machiel , Melbourne Tim , Jiang Weiping , Zhou Feng
Published: March 2020

The analysis of daily position Global Navigation Satellite System (GNSS) time series provides information about various geophysical processes that are shaping the Earth’s crust. The goodness of fit of a trajectory model to these observations is an indication of our understanding of these phenomena. However, the fit also depends on the noise levels in the time series and in this study we investigate for 568 GNSS stations across North America the noise properties, its relation with the choice of trajectory model and if there exists a relationship with the type of monuments. We use the time series of two processing centers, namely the Central Washington University (CWU) and the New Mexico Tech (NMT), which process the data using two different complete processing strategies.

We demonstrate that mismodelling slow slip events within the geodetic time series increases the percentage of selecting the Random-Walk + Flicker + White noise (RW+FN+WN) as the optimal noise model for the horizontal components, especially when the Akaike Information Criterion is used. Furthermore, the analysis of the spatial distribution of the RW component (in the FN+WN+RW) around North America takes place at stations mostly localised around tectonic active areas such as the Cascadia subduction zone (Pacific Northwest) or the San Andreas fault (South California) and coastal areas. It is in these areas that most shallow and drilled-braced monuments are also located. Therefore, the comparison of monument type with observed noise level should also take into account its location which mostly has been neglected in previous studies. In addition, the General Gauss-Markov (GGM) with white noise (GGM+WN) is often selected for the Concrete Pier monument especially on the Up component which indicates that the very long time series are experiencing this flattening of the power spectrum at low frequency. Finally, the amplitude of the white noise is larger for the Roof-Top/Chimney (RTC) type than for the other monument’s types. With a varying seasonal signal computed using a Wiener filter, the results show that RTC monuments have larger values in the East and North components, whereas the deep-drilled brace monuments have larger values on the vertical component.
Efficiency of Urban Drainage Networks: A Case Study in Seoul
Authors: Hwang Junshik , Seo Yongwon , Choi Hyun Il
Published: March 2020

The efficiency of urban drainage networks are very important within the framework of flood mitigation planning. This study suggests a methodology to evaluate the efficiency of urban drainage networks. Gibbs’s model was applied to 237 catchments in Seoul. If the parameter β is less than 100, it is regards as an inefficient network. Otherwise, it is an efficient network. The results show number of catchments with lower β is greater than with higher β. This is contradictory to common sense that urban drainage networks are efficient. Identifying the efficiency of an urban drainage networks suggest potential flood reduction by an alternative method, which is related to a layout of the networks.
Escalating risk and pronounced inter-regional differences in exposure to natural hazards due to development patterns in the United States
Authors: Iglesias Virginia , Travis William
Published: March 2020

Combined, earthquakes, fires, floods, tornados and hurricanes are the most prominent natural disturbances in the United States that endanger human lives and result in substantial costs to society. Between 2006 and 2016, property and crop damage due to these hazards increased from ~5.4 to ~ 14.6 billion USD, with the record number of billion-dollar losses set in 2017. Unprecedented impacts and escalating costs highlight the imperative for better understanding of risk, which emerges from the coupling of disturbance probability and the exposure and adaptive capabilities of local communities. This study harmonizes earthquake, fire, flood, tornado and hurricanehazard data with fine-resolution annual settlement information to assess how risk due to changes in exposure has varied over the past 40 years across the contiguous U.S.Natural hazard risk assessments have been historically hindered by scale mismatches, poor characterization of property exposure and spatially-variable accuracy of the built environment. To overcome these limitations, we combined hazard occurrence data to create an integrated hazard map and employed gridded settlement layers from the Historical Settlement Data Compilation for the U.S. (HISDAC-US) derived from cadastral and housing data compiled in the Zillow Transaction and Assessment Dataset (ZTRAX) to map exposure. HISDAC-US describes the built environment of most of the country back to 1810 at fine temporal and spatial granularity. Trends in density of structures and built-up land were estimated for hazardous and non-hazardous areas (i.e., top and bottom 10% highest and lowest probabilities of a given hazard, respectively) as well temporal dynamics of risk at the subregional-, regional- and continental-scales.  Results suggest a monotonic increase in risk to all hazards as well as pronounced and rising spatial variability in exposure, pointing to long-standing institutional issues around equity and social justice. By assessing exposure at fine spatial resolution, with high temporal accuracy, and over long periods, we reliably identified populations at risk, and evaluated the development trajectories that lead to higher vulnerability to natural hazards.
Two diode lasers with different wavelengths resonantly pumped Er:YAG ceramic single-frequency laser
Authors: Wang Lei , Mao Yefei , Lin Miaomiao , Zhang Fengrui
Published: March 2020

Single-frequency solid-state lasers have important applications in laser remote sensing, such as Doppler lidar, differential absorption lidar (DIAL), gravitational wave detection and so on. In recent ten years, highly stable and narrow spectrum single-frequency Q-switched 1.6 μm lasers are widely applied in coherent Doppler wind detection liar and CH4 DIAL. For applications in space-based wind lidar and DIAL, high output energy of the lasers is essential. In order to obtain a single-frequency laser with high energy, a common method is to inject a stable single-frequency seed laser into a high-energy Q-switched slave laser. Energy upconversion is the main factor which affects the energy enhancement of Er:YAG laser at 1.6μm. We report a Er:YAG ceramic single-frequency pulsed laser at 1645nm dual-end-pumped by two diode lasers with different wavelengths. Compared to a laser pumped by the two same wavelength diode lasers, the laser has higher slope efficiency because the energy upconversion is weakened. Otherwise, ceramic materials have many advantages compared with single crystals, such as ease of fabrication large-size ceramic material, short fabrication time, low cost and good thermo-mechanical properties. Uniform dopant can be realized in ceramic materials, which are much tougher and stronger than single crystals. All the advantages of ceramic materials mentioned above contribute to scalability to high energy laser. In this letter, we report a single frequency pulse ceramic laser with output energy of more than 10 mJ and pulse-width of more than 150 ns at a repetition rate of 500 Hz, which is pumped by two diode lasers with the wavelengths of 1470 nm and 1532 nm, respectively. This single-frequency pulse laser is a potential candidate as a seed laser for a slab laser amplifier system, which is an ideal source for space-based DIAL and Doppler wind lidar.
Long-term impact of nitrogen addition on the carbon balance of a boreal pine forest in Northern Sweden
Authors: Zhao Peng , Chi Jinshu , Nilsson Mats , Ottosson.Lofvenius Mikaell , Linder Sune , Lundmark Tomas , Marshall John , Näsholm Torgny , Peichl Matthias
Published: March 2020

Nitrogen (N) added through atmospheric deposition or as fertilizer in boreal forests may alter their carbon (C) sequestration potential and sensitivity to climatic changes. While previous studies have primarily explored the responses of individual ecosystem components such as stem biomass production and soil carbon changes following N addition, the long-term impacts of N addition on the ecosystem-scale C balance of boreal forests still remain unclear. Here, we use data from eddy-covariance measurements in a fertilized Scots pine (Pinus sylvestris L.) forest (i.e. 16 ha receiving 100 and 50 kg N ha-1 yr-1 since 2006 and 2012, respectively) and an adjacent unfertilized control stand in boreal Sweden to investigate how one decade of N addition affected the net ecosystem productivity (NEP), gross primary production (GPP) and ecosystem respiration (ER) over five fertilization years (2015-2019). Results showed that N fertilization increased GPP in all five years with by 18% at average to 1183±41 g C m-2 yr-1 in the N-fertilized stand compared to 1003±56 g C m-2 yr-1 in the control stand. ER was also increased from 744±29 g C m-2 yr-1 in the control stand to 875±37 g C m-2 yr-1 in the fertilized stand. As a result, fertilization increased NEP from 259±28 g C m-2 yr-1 in the control stand to 308±20 g C m-2 yr-1 in the N-fertilized stand. Our results further suggested that the annual NEP was similar between stands during years with normal weather conditions (2015-2016) while NEP diverged due to a larger reduction in the control stand in years with environmental constraints (i.e. a cool summer in 2017 and droughts in 2018 and 2019). These findings indicate that enhanced N input to boreal forests increases and stabilizes their C sequestration potential under future climate conditions.
Fault Fictions: Systematic biases in the conceptualization of fault zone architecture
Authors: Shipton Zoe , Roberts Jen , Comrie Emma , Kremer Yannick , Rebecca Lunn , Jonathan Caine
Published: March 2020

Mental models are a human’s internal representation of the real world and have an important role in the way a human understands and reasons about uncertainties, explores potential options, and makes decisions. However, they are susceptible to biases. Issues associated with mental models have not yet received much attention in geosciences, yet systematic biases can affect the scientific process of any geological investigation; from the inception of how the problem is viewed, through selection of appropriate hypotheses and data collection/processing methods, to the conceptualisation and communication of results. This presentation draws on findings from cognitive science and system dynamics, with knowledge and experiences of field geology, to consider the limitations and biases presented by mental models in geoscience, and their effect on predictions of the physical properties of faults in particular. We highlight a number of biases specific to geological investigations and propose strategies for debiasing. Doing so will enhance how multiple data sources can be brought together, and minimise controllable geological uncertainty to develop more robust geological models. Critically, we argue that there is a need for standardised procedures that guard against biases, permitting data from multiple studies to be combined and communication of assumptions to be made. While we use faults to illustrate potential biases in mental models and the implications of these biases, our findings can be applied across the geoscience discipline.
Barley ideotyping for the adaptation to heat stress in the Mediterranean basin. A bibliometric search approach
Authors: Fricano Agostino , Mica Erica , Battaglia Raffaella , Tondelli Alessandro , Schillaci Calogero , Perego Alessia
Published: March 2020

Barley is a widespread crop in the Mediterranean area and in temperate climates. Barley impact in the food chain is very important for its value as food and feed. The societal demand is for more productive varieties, which can be able to cope with the current and future climate scenarios. Change in climate is expected to result in more adverse conditions for the barley growth and alter land suitability in its growing regions, such as the Mediterranean basin. In this context, laboratory and modelling activities for the so-called “in silico ideotyping” can be effectively carried out to design new germplasms and to define optimal field management practices. As a first step to reach this objective, we collate the available scientific research about the identification of optimal phenotypic traits for the adaptation to harsh environments. In the framework of the GENDIBAR project (Utilization of local genetic diversity for studying barley adaptation to harsh environments and for pre-breeding; PRIMA European Funding Programme), a bibliometric analysis was carried out in the SCOPUS database with the aim to find published papers about barley adaptation in relation to changing climate. The initial query was (barley AND climate AND adaptation); it contained few keywords and resulted in less than 200 publications. By adding (barley AND ideotyping OR barley AND phenotyping), the search reached 450 records. The most comprehensive search was achieved by adding another OR condition (Barley AND future climate OR climate change) that yielded more than 1000 results. Although these records seemed relevant, a deeper analysis showed that less than 5% of these studies are of real interest and moreover the manual screening of the abstracts of all records will require around a month of work. The second query represents a compromise between the simplest query (barley AND climate AND adaptation) and the last query made by three conditions bonded together. This literature search approach highlighted the results of manipulative experiments and modelling studies for deriving phenotyping and agronomic traits to address in-silico ideotyping design. However, the search outcome suggests that there is a gap of knowledge about the barley phenotypic traits needed to cope with climate change in the semi-arid and arid regions of the Mediterranean basin. This approach is expected to further provide useful information for the development of land suitability models, as well as for barley breeding.
Baseflow measurement and analysis of Nakdong River in South Korea
Authors: Kim Ryoungeun , Kim Sangdan
Published: March 2020

The Nakdong River is the longest river in Korea with watersheds throughout the Yeongnam region of Korea, and plays an important role as a water source for agricultural water, water supply and industrial water. There is a growing recognition that baseflow measurements are important for effective water management in these large watersheds. To effectively quantify baseflow, specific conductance (SC) data is used, the most effective parameter collected continuously. The baseflow is effectively measured by using SC data and watershed information such as runoff and precipitation for tank model and soil and water assessment tool (SWAT). Our results show that a management approach that considers surface water as well as subsurface water as a resource is important for the effective management of current and future water resources.

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2019R1A2C1003114).
Land Atmosphere Feedback Observatory (LAFO) and heterogeneous terrain in its footprint
Authors: Rajtschan Verena , Späth Florian , Streck Thilo , Wulfmeyer Volker
Published: March 2020

Soil, land cover and the lower atmosphere form the land atmosphere system. The feedbacks in this system are nonlinear, because of two-way coupling between single variables such as soil moisture and precipitation. A detailed characterization of fluxes and feedbacks within and between the different compartments is essential to improve our understanding of the land atmosphere system. To investigate these fluxes and feedbacks the Land Atmosphere Feedback Observatory (LAFO) was established at the experimental station “Heidfeldhof” of the University of Hohenheim in 2018. LAFO applies a novel synergy of eddy covariance stations, vegetation measurements, and innovative scanning lidar systems. The measurements are comprehensive, highly resolved and very precise, so that new parameterizations of land-atmosphere exchange processes between soil/vegetation and the lower troposphere for model systems can be developed, implemented, and tested.

LAFO is situated in heterogeneous cropland with nearby urban areas and forests. The heterogeneous terrain forms a complex land atmosphere system. A footprint analysis of eddy covariance data from 2019 enables us to better characterize our site.  Here we present LAFO, its concept and first results on a footprint analysis of the eddy covariance data.
Early Holocene presences of Norway spruce (Picea abies L. Karst.) at high latitudes in Norway and Sweden: the genetic story of up to 9550 year old spruce clones in the Scandinavian mountains
Authors: Nota Kevin , Parducci Laura
Published: March 2020

The survival of boreal trees in ice-free cryptic refugia’s at high latitudes during the Last Glacial Maximum has been subjected to a long-standing debate. Norway spruce (Picea abies L. Karst) is generally believed to have recolonised Scandinavia from the east. Spruce appears for the first time in the pollen assemblages in central Sweden around 3000 years before present (yr BP), however, a growing body of macrofossil and genetic evidence suggested that spruce might have survived in ice-free areas around the Norwegian shore or closer to the Weichselian ice sheet than previously thought. These satellite populations may have contributed to the recolonisation of Scandinavia from the west and may be ancestors to the ancient (up to 9550-year-old) but still living clonal spruce trees occurring today in the Scandinavian mountains (e. g. Old Tjikko and Old Rasmus). Genetic research has shown that modern P. abies contain two sequence variants for the maternal inherited mitochondrial mh05 fragment across its Eurasian distribution, of which one is unique to Scandinavia. The Scandinavian variant shows the highest frequency in western Scandinavia and its modern distribution suggests that it was already present before the last glacial period. The Scandinavian variant was also detected in lake sediment dating back to 10300 yr BP at Trøndelag in Central Norway (63°N).

 We are using sensitive melting curve qPCR assay and high-throughput sequencing to detect the presence of the Scandinavian variant in several sediment cores covering Scandinavia and north-east & southern Russia. So far, the qPCR melting curve assay detected the Scandinavian variant in peat sediment from northern Finland (~52,000 – 42,000 yr BP), in lake sediments in central Sweden and central Norway (~10,000 – 900 yr BP) and in southern Sweden (~12000 – 11000 yr BP), which is far earlier than currently believed. Additional lakes are being processed and samples positive for the Scandinavian variant will be sequenced to confirm sequence identity. We are also conducting population genetic analysis of the ancient clonal spruce stands to see how these trees are related to the modern spruce forest and weather they have contributed to the recolonization of Scandinavia. The results of this study will increase our understanding of the post glacial colonisation of P. abies in Scandinavia after the Last Glacial Maximum.
Active subglacial volcanism in West Antarctica as assessed by airborne geophysics: Distribution and context
Authors: Blankenship Donald , Quatini Enrica , Young Duncan
Published: March 2020

A combination of aerogeophysics, seismic observations and direct observation from ice cores and subglacial sampling has revealed at least 21 sites under the West Antarctic Ice sheet consistent with active volcanism (where active is defined as volcanism that has interacted with the current manifestation of the West Antarctic Ice Sheet). Coverage of these datasets is heterogenous, potentially biasing the apparent distribution of these features. Also, the products of volcanic activity under thinner ice characterized by relatively fast flow are more prone to erosion and removal by the ice sheet, and therefore potentially underrepresented. Unsurprisingly, the sites of active subglacial volcanism we have identified often overlap with areas of relatively thick ice and slow ice surface flow, both of which are critical conditions for the preservation of volcanic records. Overall, we find the majority of active subglacial volcanic sites in West Antarctica concentrate strongly along the crustal thickness gradients bounding the central West Antarctic Rift System, complemented by intra-rift sites associated with the Amundsen Sea to Siple Coast lithospheric transition.
Beyond Normality: Estimation of Near-Bed Sediment Concentrations Accounting for Asymmetric Distribution and Spatial Influence of Turbulence Coherent Structures
Authors: Tsai Christina , Wu Kuan-Ting
Published: March 2020

Abstract

Recent experiments have established that the sediment particle motion, especially for particles near the bed, may not follow the normal (Fickian) diffusion behavior. To modify the diffusion equation where the fluctuation velocity is based on the normal distribution, this investigation hypothesizes that the fluctuation velocity based on bivariate probability distributions and particle-bed collision in open channel can provide some physical insight into the particle diffusion behavior. The distribution of fluctuation velocity is obtained using the Gram-Charlier expansion which considers the first four statistical moments of turbulent fluctuation velocity. The correlation between two-dimensional fluctuation velocities is modeled by performing Monte Carlo simulations. Besides, the uniform momentum zones (UMZ) are further identified and consequently the spatial locations of the edges that demarcate UMZs can be estimated. Once UMZs in the turbulent boundary layers can be characterized, the streamwise momentum deficit, and occurrences of ejection events and sweep events in the vicinity of UMZ edges under different Reynolds numbers can be simulated. The spatial influence of turbulent coherent structures on sediment particle trajectory can be demonstrated.
Overdeepened glacial basins as archives for Pleistocene glaciation history and subglacial processes: Results from scientific drilling in the Northern Alpine Foreland
Authors: Buechi Marius W. , Deplazes Gaudenz , Gegg Lukas , Madritsch Herfried , Anselmetti Flavio S.
Published: March 2020

Overdeepened glacial basins are excellent archives for the Quaternary glaciation history and the landscape evolution of the Alps. While they are common large-scale glacial features in many inner-Alpine and foreland settings, most of these basins remain underexplored as challenging drilling operations into 10s to 100s of meters of unconsolidated sediment are required to access the sedimentary record.

We currently investigate some of the most prominent overdeepened glacial basins between the Aare and Rhine Rivers in Northern Switzerland with a multi-method approach –  including geophysical methods and scientific drilling – to characterise the geometry, sedimentary infill and age of these glacial basins. The focus of this research is on 1) extracting and refining the Middle to Late Pleistocene glaciation history of Northern Switzerland, and 2) identifying the mechanisms and controls of overdeepening subglacial erosion by characterizing former ice-contacts in the basin fills using micro- to macroscale sedimentological tools.
Development of Podzols in relation to Jenny's soil formation factors
Authors: Törmänen Tiina , Lindroos Antti-Jussi , Ilvesniemi Hannu , Starr Mike
Published: March 2020

Podzols are considered to be the most common upland forest soil type in Finland. However, there have only been a few studies that have examined the degree of podsolization in Finnish soils. More detailed information about this dominating process in our soils can be utilized in other kinds of environmental research such as the impacts of climate change, carbon and nutrient cycling, and the degradation of soil and water systems.

We studied how the intensity of podsolization is related to Jenny’s classic five soil formation factors: climate, parent material, topography, biotic and time. The degree of podzolization of 86 soil profiles distributed over the whole of Finland was described using four podzolization indices: E-horizon thickness, B-horizon rubification, profile Al+Fe oxide eluviation-illuviation, and their sum (Podzolization Development Index, PDI). The soil profiles, selected out of over 600 soil profiles in a national database, met the World Reference Base for Soil Resources (WRB) criteria for them to be classified as Podzols. The relationship between the podzolization indices and a number of site and soil variables (continuous and categorical) describing Jenny’s soil formation factors were then evaluated. While podzolization intensity was found to be related to soil profile age, elevation, longitude, forest site type, aspect, Sphagnum moss cover and B-horizon texture, the individual relationships were weak. However, looking at the combined effect of all the variables using Partial Least Squares regression analysis, which is unaffected by multicollinearity among the predictor variables, nearly 70% of the measured PDI index could be explained.
Survey on early career travel support shows geographic, career stage, and indigenous status inequality in access to polar science events
Authors: Savaglia Valentina , Bradley Alice , Höfer Juan , Eayrs Clare
Published: March 2020

The Association of Polar Early Career Scientists is an international organization with membership representing 70 countries. Members are mostly graduate students and post-docs, though 29% are early career professionals in other polar-related career tracks. A survey was sent in summer 2019 to APECS members and polar science community members asking about travel support needs and how respondents’ recent travel was funded. Participants described the perceived availability of different types and sources of travel funding. Availability of travel awards and the expectation that early career researchers would pay for their meeting-related travel out of personal funds varies widely between countries, career stage and indigenous status. Substantially higher travel support is often needed to support participants from countries outside the US, Canada, and Northern Europe because of both the higher cost of traveling to typical meeting destinations coupled with lower availability of supplemental or full travel support. This presentation will cover the international patterns in early career travel funding, the utility of travel advances and the importance of making funding decisions eaerly enough for ECRs as a way to promote diversity in polar sciences.
Risk analysis approach for tipping cascades and domino effects in the Earth system under global warming
Authors: Donges Jonathan , Wunderling Nico , Kurths Jürgen , Winkelmann Ricarda
Published: March 2020

Tipping elements in the Earth's climate system are continental-scale subsystems that are characterized by a threshold behavior with potentially large short- to long-term impacts on human societies. It has been suggested that these include biosphere components (e.g. the Amazon rainforest and coral reefs), cryosphere components (e.g. the Greenland and Antarctic ice sheets) and large-scale atmospheric and oceanic circulations (e.g. the AMOC, ENSO and Indian summer monsoon). Interactions and feedbacks of climate tipping elements via various processes could increase the likelihood of crossing tipping points under a given level of global warming and interaction strength. However, studying these potential domino effects and tipping cascades with process-detailed state-of-the-art Earth system models is difficult so far, because relevant tipping elements are often not represented and uncertainties in their properties and interactions are large.

To bridge this current gap in the model hierarchy, we present a risk analysis approach based on a paradigmatic model of interacting tipping elements that propagates uncertainties in interaction structure, sign and strength as well as critical thresholds and other parameters via large Monte Carlo ensembles. Our approach allows to study the likelihood of domino effects and tipping cascades to emerge due to pairwise interactions and feedbacks to global mean temperature. We apply our approach to a subset of five potential tipping elements (Greenland and West Antarctic ice sheets, AMOC, Amazon rainforest and ENSO) with known parameter uncertainty estimates and find that their interactions overall tend to be destabilizing. The presented framework is flexible and can be adapted to study the interaction effects of other or additional tipping elements and more detailed submodels for describing their individual dynamics.
Assessing climate impacts on English economic growth (1645–1740): an econometric approach
Authors: Martinez-Gonzalez José Luis
Published: March 2020

British pre-industrial economic growth has traditionally been analysed from the Malthusian point of view and other more optimistic approaches, but in many cases, ignoring environmental factors. This article explores the inclusion of the climate in this general debate, focusing on one of the colder periods of the last 500 years, known as the Maunder Minimum. The provisional results suggest that climate change and the resulting adaptations may have influenced the start of the English Agricultural Revolution, the Energy Transition and the European Divergence. However, from an econometric point of view these results are not fully conclusive, making it necessary to continue working with better primary sources and other alternative methodologies.
Multi-objective optimization of ecosystem services in an agricultural intensive watershed
Authors: Kong Lingqiao
Published: March 2020

The complex trade-offs of ecosystem services make ecosystem management difficult to achieve win-win goals, especially in a watershed with intensive agriculture. Although a lot of research has been carried out on the types, characteristics and harmonized measures of ecosystem service trade-offs, how to achieve synergistic gain through effective land use management still lacks quantitative Optimization. Combined with models of land use optimization and spatially assessment of ecosystem services, the study build a multi-objective function and a land use optimization method to realize maximization of the total benefit based on the characteristics of ecosystem service trade-off and the driving factors in the Dongting Lake watershed， which is one of the priority areas for ecological protection in China and is also agricultural intensive. First we quantitatively model the water purification service, sediment reduction service and agricultural production using field observation and spatial models of ecosystem services, then the integrated response characteristics of multi-objectives are analyzed according to different land use scenarios based on driven mechanism of ecosystem service trade-offs. Finally the way of optimizing land use allocation and synergetic development of multiple ecosystem services in the watershed is proposed to provide quantitative means for regional land use optimization.
Drought Management Plans in Spain: Are we improving the way we manage drought?
Authors: Urquijo Reguera Julia , Gómez Villarino María Teresa , De Stefano Lucia
Published: March 2020

Droughts affect all the socio-economic sectors and can have negative impacts on the environment. They are expected to increase in frequency and severity due to climate change, which makes their effective management a policy priority. Drought Management Plans (DMPs) are considered to be a key instrument to deal with drought in a proactive way, as they establish a framework for coordinated action when drought sets in. The development of DMPs is still incipient worldwide and the evaluation of their quality and performance is still very limited. In Spain, DMPs at river basin level were first approved in 2007. Following the legal obligation set in the Spanish law, those DMPs were revised after 10 years and a new version was approved in 2018. In order to analyze the adequacy, pertinence and utility of those plans, we developed a protocol based on content analysis for evaluating the DMPs of the eight river basins that are managed by the Spanish Central Government. We set the evaluation criteria using official guidelines and scientific literature on drought preparedness and we compared the first and the second round of DMPs to identify the main improvements, gaps and challenges. The comparison was both qualitative and quantitative, through the establishment of quality criteria/indicators.

The analysis showed that the scope and content of the DMPs is more homogeneous and consistent in 2018 than in 2007. Some aspects have clearly improved between the two planning periods, like the distinction between drought and water scarcity, the definition of indices to trigger different levels of drought alert and the inclusion of measures for drought management and coordination. Other issues still need further improvements, especially those related to the analysis of drought impacts, the assessment of vulnerability and the ex-post evaluation of DPM performance.

The DMPs developed for the Júcar and Segura river basins, both located in the Mediterranean region and prone to severe droughts, received the highest score according to our assessment criteria. All the DMPs show some improvements between 2007 and 2018, but the largest increase corresponds to the Duero river basin while the least is for the Júcar.
Observational constraints for European climate projections
Authors: Qasmi Saïd , Ribes Aurélien , Douville Hervé
Published: March 2020

Observational constraints involve the combined use of models and observations in order to assess their consistency, and aim to reduce the uncertainty on future climate using past information. Several constraints are investigated with the CMIP5 models and re-examined in the light of newly available CMIP6 data. This includes constraints based on detection-attribution approaches and physically-based constraints, in particular those related to the water cycle (e.g. soil moisture, clouds, snow cover). A wide range of methods is used to provide a probabilistic description of future changes address the issue of combining together multi-model ensembles of projections, and a large number of observational constraints. Uncertainty quantification techniques are used to assess the sensitivity of the results (i) to the used method and (ii) to the internal variability.