bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of methods for initialization of the Open Global Glacier Model (OGGM)
Authors: van der Laan Larissa , Eis Julia , Förster Kristian , Marzeion Ben
Published: March 2020

 In order to assess glacier mass balance on large temporal and/or spatial scales, numerical modelling is an essential tool, complementing ground observations and remote sensing methods. For a reliable simulation of a glacier’s development over time, knowledge of its initial state is fundamental. Attaining this information entirely through empirical evidence is impossible due to a lack of data, hence the need for alternative, numerical methods. In this study, three methods of varying complexity are applied to initialize the Open Global Glacier Model (OGGM) for 254 glaciers. These glaciers have a minimum of 5 years of in-situ mass balance observations, allowing for direct comparison with modelled values. The initialization methods comprise, in brief, i) a basic spin-up, starting from present-day conditions, running the model for 200 years with a random climate, representative of the period 1900-2000 ii) a cold climate spin-up, allowing the glacier to grow and create a more representative initial condition for e.g. the year 1901 and iii) a synthetic experiment based on present day glacier observations and past climate information, used to generate a large set of physically plausible initial states, which are then evaluated. Using each method, we reconstruct the glaciers’ initial states and set up a forward run from which to extract mass balance values over the time period 1970-2014, used for validation purposes. The overall aim is to identify an initialization approach that can be successfully applied to our current set of 254 glaciers, as well as areas with even sparser data available, expanding the range of scale for glacier modelling.
GEOTRIVIAL PURSUIT: discovering the earth planet
Authors: Misiti Valeria , Riposati Daniela , Di Laura Francesca , Crescimbene Massimo
Published: March 2020

TheEarth is a fascinating place that host wonders such as volcanoes, rivers, deserts and more.Our idea has been that to produce a scientific game named GEOTrivial which is a tool to learn more about the amazing world of geosciences by enjoying.

Based on the enthusiasticfeedback obtained with “Escape Volcano” project (presented last year at the EGU 2019)and the success in the schools where we presented it, the next step encouraged us to develope a new project.

The graphic realization of all elements of the new GeoTrivial game (board, cards, dice) was developed within the INGV by the Laboratorio Grafica e Immagini.

Graphic is a fundamental support for the game production because every elements have been deeply studied creating icons similar to the social ones, to create a familiar connection for people. The use of a particular lettering, that strongly connoted the visual aspects, in the main components of the game, is dictated by the need to create a dominant visual element of the entire project that conveys a sense of dynamism, of freedom, but also lightness.

Basically the game revisit the classic trivial but on the game board volcanoes, epicenters and a drop of water are reported to direct immerse the players on the earth planet science. The game can be played as a team or single player (from 2 to 24 players).The game board is shaped like a 3-spoke wheel. Player begin at the center rolling the die. When the player reach the space then a different player draws the card and reads the question. The player move forward in any direction, but he can never retrace the steps on the same roll. Two player may occupy the same space. There are 4 answers on the card but only one is correct; the opponent team read the question and the answers. Player the land on the center square may choose the color he/they wish the question to be read from. He/they may not know the questions before choosing the color.

The player may continue to roll as long as he keep answering the questions correctly; there is no limit. If the answer is incorrect, then the turn passes to the left. “Roll again” spaces allow to move the die again without answering any questions.

Once the token is complete the player must try to land on the center space where the game started. The opponents decide the category you are to answer from before the look at the card. If the player/s answer the final question successfully he/they win the game.

This new game belongs to an editorial project dedicated by the INGV to education and outreach.

Enjoy!
Electron Flux and Precipitation During ICME Case Studies
Authors: George Harriet E. , Kilpua Emilia , Osmane Adnane , Asikainen Timo , Rodger Craig J. , Kalliokosi Milla , Palmroth Minna
Published: March 2020

Interplanetary coronal mass ejections (ICMEs) can dramatically affect electrons in the outer radiation belt. Electron energy flux and location varies over a range of timescales during these events, depending on ICME characteristics. This highly complex response means that electron flux within the outer radiation belt and precipitation into the upper atmosphere during ICMEs is not yet fully understood. This study analyses the electron response to two ICMEs, which occurred near the maximum of Solar Cycle 24. Both ICMEs had leading shocks and sheaths, followed by magnetic flux ropes in the ejecta. The magnetic field in these flux ropes rotated throughout the events, with opposite rotation in each event. The field rotated from south to north during the first event, while the second event had rotation from north to south. Data from Van Allen Probes were used to study electron flux variation in the outer radiation belt, while POES data were used for electron precipitation into the upper atmosphere. Qualitative analysis of these data was carried out in order to characterise the temporal and spatial variations in electron flux and precipitation throughout these two events, with particular focus on the effects of the sheath and rotating magnetic field in the ICME ejecta. In both events, we observe enhanced precipitation at mid-latitudes during the southward portion of the ejecta, with greater enhancements taking place in lower energy electron populations. By contrast, flux of outer radiation belt electron populations differs significantly between the two ICMEs, highlighting the complexity of the electron flux response to these space weather events.
Tracking Late Quaternary ice sheet dynamics by multi-proxy detrital mineral U-Pb analysis: A case study from the Odyssea contourite, Ross Sea, Antarctica
Authors: Neofitu Roland , Mark Chris , Rebesco Michele , Lucchi Renata Giulia , Douss Nessim , Morigi Caterina , Kelley Sam , Daly J. Stephen
Published: March 2020

Late Quaternary Antarctic ice-sheet instability is recorded by ice-rafted debris (IRD) in mid- to high-latitude marine sediment, especially during marine isotope stages (MIS) 2-3, but drivers of this instability remain enigmatic (Labeyrie et al., 1986). A key step in resolving this puzzle is to determine the location of iceberg calving sites, thus highlighting ice sheet sectors exhibiting repeated instability. Single-grain U-Pb provenance analysis applied to clastic IRD provides a suitable high-resolution tool for this task, and also permits discrimination of continental IRD from volcanic material. The application of multiple proxies (apatite, rutile, and zircon) is critical in order to reduce source area fertility biases: for example, the near exclusive occurrence of zircon in felsic-intermediate igneous rocks (e.g., Hietpas et al., 2010).

Here, we present detrital apatite, zircon, and rutile U-Pb data from samples taken from a gravity core from the Odyssea contourite drift system, located on the margin of the Ross Sea (Rebesco et al., 2018) and deposited during MIS2-3. Contourites are marine clastic sediment deposits forming by along-slope, bottom currents reworking of fine-grained (clay-silt) sediments delivered by down-slope sedimentary processes (e.g. meltwaters, turbidity currents, debris flows). Crucially, contourite targetting eliminates the challenge of distinguishing IRD from coarse (sand-gravel) turbidite material in basin deposits, as ice-sheet instability is also associated with turbidite production at glaciated shelf margins (e.g., Bart et al., 1999).

We couple our analysis with the multi-proxy sediment analyses previously performed by Lucchi et al. (2019). We consider the implications of our data for the advance and retreat of the Antarctic Ice Sheet during MIS 2-3, and discuss the further applicability of our multi-proxy approach around Antarctica.

Bart, P.J, et al., 1999, Journal of Sedimentary Research, v. 69, p. 1276–1289, doi:10.2110/jsr.69.1276.

Hietpas, J, et al., 2010, Geology, v. 38, p. 167–170, doi:10.1130/G30265.1.

Lucchi, R.G, et al., 2019. EGU General Assembly 2019, Vienna April 7th–12th, Geophysical Research Abstracts Vol. 21, EGU2019-10409-1

Rebesco, M, et al., 2018, preliminary results, in POLAR 2018 SCAR/IASC Open Science Conference, v. GG2 Arctic, p. 14133.

Labeyrie, L, et al., 1986, Nature, v. 322, p. 701–706.
On the droplet spectral broadening numerics
Authors: Olesik Michael , Bartman Piotr , Arabas Sylwester , Abade Gustavo , Baumgartner Manuel , Unterstrasser Simon
Published: March 2020

Owing to its key role in determining both the droplet collision probabilities and the radiative-transfer-relevant spectrum characteristics, the evolution of droplet spectral width has long been the focus of cloud modelling studies. Cloud simulations with detailed treatment of droplet microphysics face a twofold challenge in prognosing the droplet spectrum width. First, it is challenging to model and numerically represent the subtleties of condensational growth, even more so when considering the interplay between particle population dynamics and supersaturation fluctuations. Second, the discretisation strategies employed in representing the particle size spectrum and its evolution are characterised by inherent limitations. 

In the poster, we will present results of both Eulerian and Lagrangian numerical representations of spectrum width evolution. In the case of Lagrangian approach, we will discuss the differences in numerical integration procedures between (a) the sophisticated solvers typically used in parcel-model frameworks with moving-sectional spectrum representation and (b) the simpler solvers typically used in mathematically-analogous particle-based (super-droplet) microphysics representations used in multi-dimensional models.

In the case of Eulerian (bin microphysics) approach, we will present condensational growth simulations performed with the MPDATA numerical scheme using the newly developed MPyDATA package (http://github.com/atmos-cloud-sim-uj/MPyDATA/). The MPDATA family of numerical schemes for solving advective transport problems has been in continuous development for almost four decades. MPDATA features a variety of options allowing to pick an algorithm variant appropriate to the problem at hand. We will focus on the importance the MPDATA algorithm variant choice and the grid setup for the resultant numerical diffusion.

In the case of Lagrangian approach, we will present simulations performed using the newly developed PySDM package (https://github.com/atmos-cloud-sim-uj/PySDM) that features a set of cloud microphysics algorithms including condensational growth solvers. In the discussion, we will focus on: (a) the numerical realisability of the Ostwald ripening process (i.e. the growth of larger particles at the expense of water content of the smaller ones) and (b) the numerical approaches available for integrating stochastic fluctuations of ambient thermodynamic properties that drive the water vapour saturation.
Images Time Series Analysis for Land Deformation and Mapping Shallow Landslides based on SENTINEL - 1 and Optical Satellite Images Data: Case Study on Batam Island, Indonesia
Authors: Choanji Tiggi , Jaboyedoff Michel , Derron Marc-Henri , Fei Li , Sun Chunwei
Published: March 2020

As a growing city, Batam Islands has an immense potential to become one of the strategic positions in Southeast Asia. However, as the city developed, it also followed with the deformation and potential areas which has prone to shallow landslides. Using 32 Sentinel-1A Satellite Images Data and 17 years of Optical images data, analysis of time series is conducted using Persistent Scattered Interferometry method and mapped for landslide events in the Islands. As a result, several regions impacted 4 – 10 mm/year of velocity deformation in the center part of the island and several locations simulated to be prone to shallow landslide. So, by coupling method of SAR data and optical images, has giving prominent possibility for detecting and predicting hazard potential in this island.
Assessment of the future climate potential for tourism over Europe using a combination of downscaling approaches and quantitative impact models
Authors: Cardell Maria Francisca , Amengual Arnau , Romero Romualdo
Published: March 2020

Europe and particularly, the Mediterranean countries, are among the most visited tourist destinations worldwide, while it is also recognized as one of the most sensitive regions to climate change. Climate is a key resource and even a limiting factor for many types of tourism. Owing to climate change, modified patterns of atmospheric variables such as temperature, rainfall, relative humidity, hours of sunshine and wind speed will likely affect the suitability of the European destinations for certain outdoor leisure activities.

Perspectives on the future of second-generation climate indices for tourism (CIT) that depend on thermal, aesthetic and physical facets are derived using model projected daily atmospheric data and present climate “observations”. Specifically, daily series of 2-m maximum temperature, accumulated precipitation, 2-m relative humidity, mean cloud cover and 10-m wind speed from ERA-5 reanalysis are used to derive the present climate potential. For projections, the same daily variables have been obtained from a set of regional climate models (RCMs) included in the European CORDEX project, considering the rcp8.5 future emissions scenario. The adoption of a multi-model ensemble strategy allows quantifying the uncertainties arising from the model errors and the GCM-derived boundary conditions. To properly derive CITs at local scale, a quantile–quantile adjustment has been applied to the simulated regional scenarios. The method detects changes in the continuous CIT cumulative distribution functions (CDFs) between the recent past and successive time slices of the simulated climate and applies these changes, once calibrated, to the observed CDFs. 

Assessments on the future climate potential for several types of tourist activities in Europe (i.e., sun, sea and sand (3S) tourism, cycling, cultural, football, golf, nautical and hiking) will be presented by applying suitable quantitative indicators of CIT evolutions adapted to regional contexts. It is expected that such kind of information will ultimately benefit the design of mitigation and adaptation strategies of the tourist sector.
Satellite remote sensing of ice cliff migration
Authors: Altena Bas , Kääb Andreas
Published: March 2020

Ablation patterns on debris-covered glaciers are highly complex and spatially variable, while accessibility is complicated due to steep topography and loose surface debris material. One of the main ablation components on debris-covered glaciers is ice melt on steep ice cliffs and associated cliff migration. When using measurement techniques that operate in absolute coordinates, a main challenge is to separate cliff retreat from the underlying ice movement. In-situ measurements are spatially limited, while giving highly detailed understanding of processes occurring on individual ice cliffs. Drones can extent such detailed measurements to a whole glacier tongue, but are still limited to a few glaciers and measurement times. Here we show how measurements of cliff migration rates towards a regional scale are possible with spaceborne optical instruments. For this study we focus on the Mt. Everest region, specifically the Khumbu Glacier and other glaciers in the surrounding. We use Venμs, a French-Israeli multi-spectral satellite, that provides images at high temporal resolution (a two day repeat), and at high spatial resolution (5m), at this spatial resolution it provides sufficient detail to investigate individual ice cliffs.

Migration of ice cliffs can have a dominant direction, but their shape evolves over time, complicating pattern matching. Similar challenges occur for velocity extraction of the underlying glacier ice, where the shadow casted by ice cliffs is a dominant feature on glacier imagery, thus instead of debris patterns, the velocity estimates have ice cliff migration patterns within. Hence, in order to reduce the interference between both processes we reduce the influence of shadow within the imagery and extract bulk glacier ice velocity. While specific ice cliff features are isolated and tracked. Thus different image tracking techniques are deployed, in order to distinguish one displacement from the other.

The ice-cliff migration can be separated from the general glacier velocity, which results in a regional estimate of ice cliff back wasting, and thus a proxy for clean ice mass-balance of debris-covered glaciers from space. Venμs is a demonstrator satellite, with a limited lifetime and acquisition strategy, but our automatic methodology is generic and can be transferred to, for example, the 10m imagery from Sentinel-2, making regional analysis feasible.
Real neutralization reactions of amines against ammonia by acids in ambient air
Authors: Chen Dihui , Zhu Yujiao , Shen Yanjie , Yao Xiaohong
Published: March 2020

Amines reportedly overwhelm ammonia in generating new particles through neutralizing sulfuric acid vapor even with several orders smaller concentrations of amines against ammonia in ambient air, demonstrating an attractive prospect in adjusting concentrations of amines to adjust aerosol number loadings, alleviate air pollution and manipulate aerosol cooling effects. Due to lack of in-situ observations, real competition of amines against ammonia in ambient air to be neutralized by acids remains poorly understood. Here, successful semi-continuous measurements of gaseous amines and ammonia and their particulate partners in marine atmospheres reveal that atmospheric trimethylamine (TMAgas) unable to compete with NH3gas and to form particulate trimethylaminium (TMAH+), but the particulate TMA (TMAparticulate) is detectable and comparable to TMAgas under NH3gas <1.0 µg m-3. Contradictory to the common knowledge, the preexisting TMAparticulate is largely depleted in strong SO2 plumes with abundant acids and even depleted NH3gas. A two-aerosol-phase transfer concept model is proposed to interpret the new findings, but no single-phase acid-base neutralization reactions can. In contrast, observational evidences confirm that gaseous dimethylamine (DMAgas) plus particulate dimethylaminium (DMAH+) overwhelmingly exist as DMAH+ under atmospheric NH3 (NH3gas) <0.3 µg m-3 versus DMAgas under NH3gas >1.8 µg m-3, respectively. The neutralization of DMAgas to form DMAH+ is always enhanced in strong SO2 plumes, almost independent on NH3gas. Thermodynamically, DMAgas may act as a competitor in generating secondary particles only under low NH3gas or in SO2 plumes.
Multi-phase development of the Porcupine Basin during the rifting of the North-Atlantic
Authors: Lymer Gaël , Roche Vincent , Saqab Muhammad , Childs Conrad , Walsh John
Published: March 2020

The hyper-extended Porcupine Basin, offshore southwest Ireland, is a component of the Eastern North Atlantic rifted continental margin. The basin developed following multiple rifting phases with different extension directions between the Late-Palaeozoic and the Cenozoic. The present-day north-south trend of the Porcupine Basin developed during the main Middle-Jurassic to Lower-Cretaceous rifting phase, which is interpreted to have overprinted earlier extension directions. In this study, we outline the tectono-stratigraphic architecture and the kinematics of the Porcupine Basin derived from seismic interpretation and fault analysis of multiple 2D and 3D seismic datasets.

Our ongoing work identifies different fault networks with distinctive orientations and ages, confirming multiple rifting phases of the basin. The older faults identified strike NE/SW and offset the top of the Jurassic basement and the oldest syn-tectonic sequences. The younger faults strike N/S, offset the whole syn-tectonic stratigraphic sequence and bound the present-day tilted blocks of thinned continental crust. Interactions between these two main generations of faults created strong lateral variability in the geometry of the fault-bounded blocks. In addition, our interpretations highlight strong segmentation along the axis of the basin, evidenced by changes in the structural architecture of the faults along the flanks of the basin, and by rapid changes in the depth to the Jurassic basement from one segment to another. This segmentation occurs across several lineaments that are orthogonal to the main N-S direction of the tilted blocks observed along the flanks of the basin, and that are also observed in the central parts of the basin with gravity data and by the compartmentalisation of sedimentary depocenters. We interpret these lineaments as transfer zones that can be related to the kinematics of the basin. These zones may have accommodated either temporal or spatial changes in the directions of extension, or a stepped variation in E-W extension along the axis of the basin.

Our results help to better understand the controls on the geometry and kinematics of fault systems within the Porcupine Basin, and to better evaluate the structural evolution of the Porcupine Basin and its significance in the broader context of the North Atlantic rifting.
Thermokinetic characteristics of coal spontaneous combustion of Jurassic coal from China
Authors: Zhao Jingyu , Deng Jun , Kang Furu , Song JiaJia
Published: March 2020

Jurassic coal samples from two coal mines were selected for oxidative thermal energy experiments. By using a temperature-programmed experimental system, the variation of gaseous products was obtained, and the changes in thermal energy release with temperature were measured. Thermokinetic parameters, such as apparent activation energy (Ea) and pre-exponential factor (A), of the coal samples under four different heating rates, were determined by thermogravimetric analyzer. The results showed that during the low-temperature oxidation stage, the index gas (CO) used to characterize the spontaneous combustion state of the coal body was roughly the same as the temperature curve of the two samples with the temperature change, but the critical temperature was different. The WD sample produced less CO gas. However, the maximum and minimum exothermic strengths of the two samples showed similar to temperature change curves. The characteristic temperatures for coal were discovered using different heating rates. For the WD sample, the characteristic temperature varied according to the heating rate. For the same type of sample, the TG and DTG curves lagged with an increase in heating rate. Characteristic temperatures T1−T5 had an increasing tendency with an increase in heating rate. As one of the integral methods, Coats-Redfern integral method was adopted to capture the thermokinetic parameters of the samples. The straight line fitting by this method was higher. The heating rate conditions increased from 2 to 15 °C min-1 when the oxygen concentration was 21 vol%, the apparent activation energy of the samples decreased with an increase in the heating rate.
Water-soluble organic matter and enzymatic activity of urban soils of Rostov aglomeration
Authors: Sergey Gorbov , Pavel Skripnikov , Olga Bezuglova
Published: March 2020

Soil water-soluble organic matter (WSOM) is the most dynamic and least stable component of humus. It takes a direct part both in leading soil processes and in the formation of effective soil fertility. Its components are involved in the creation of a water-resistant structure, also exhibit physiological activity, and be of service as energy material by microorganisms. The total content of organic matter in the soils of the Rostov agglomeration varies widely: from 1.5 to 7.0%. Long-term studies of soils of the Rostov agglomeration forest-park zones showed that the organic carbon content in these soils increases under tree vegetation. This is due to changes in microclimate conditions and the associated longer period of vegetation of herbaceous vegetation. The WSOM content was obtained by summing the results of cold and hot extraction in natural soils. Its gradually decreases with depth repeating the profile dynamics of the organic carbon content in general. The surface horizons of native chernozems in a forest park and in a virgin land have the highest content of WSOM. It can be concluded that the WSOM pool is directly proportional to the stock of incoming plant residues. The maximum of extracellular enzymes activity was obtained in upper most biogenic soil horizons in the natural city soils. The highest activity was record for the enzyme, which is responsible for the nitrogen cycle (arginine-aminopeptidase (Agr)) and for the phosphorus cycle (acid phosphatase (Pho)). The enzymes activity decreases down the soil profile. 

For anthropogenically transformed soils, the WSOM profile distribution indicates a peculiar two-member structure of soil profile. The transformed upper urbiс horizons was demonstrate the absence of any patterns in its distribution. In the buried horizons of Technosols, were have the same profile trends and the same absolute values of the organic carbon content such us presented in native chernozems. Despite the high humus content in natural soils (5–7%), most of it is strongly associated with calcium ions. As a result, WSOM has values not exceeding 0.14% of the soil as a whole, or 4% in terms of organic carbon. For the urban horizons of anthropogenically transformed soils, WSOM values are not exceeding 0.04% of the soil, or about 2% in terms of organic carbon. The inversions of enzyme activity are often observed in anthropogenically transformed soils. The enzymatic activity is higher in buried humus-accumulative horizons of urbostratozems than in overlying horizons of the urbic. 
Global and free geospatial datasets for the study of floods, droughts and human societies
Authors: Lindersson Sara , Brandimarte Luigia , Mård Johanna , Di Baldassarre Giuliano
Published: March 2020

The availability of planetary-scale geospatial datasets that can support the study of water-related disasters in the Anthropocene is rapidly growing. We review over hundred global and free datasets allowing spatiotemporal analyses of floods, droughts and their interactions with human societies. The purpose of structuring a data collection for a broad range of variables is to foster data exchange and illustrate research opportunities across scientific disciplines.

Our collection of datasets confirms that the availability of geospatial data capturing hydrological hazards and exposure is far more mature than those capturing vulnerability aspects. We do not only highlight data applications by listing a selection of recent studies exploiting these global datasets, but also discuss challenges associated with using these datasets in comparative studies.  Specific discussion points include spatiotemporal resolution and coverage, inequalities of geographic representation, omission of detailed information at large scales, data consistency and accessibility, and dependencies between the datasets prohibiting interaction studies.
New insights into the Evaluation of Financial Impact of Earthquakes in France: Benefits for Compensation and Prevention
Authors: Tinard Pierre , Rey Julien , Monfort-Climent Daniel , Imtiaz Afifa , Hoste-Colomer Roser , Negulescu Caterina , Gehl Pierre
Published: March 2020

Models designed to estimate financial impact of earthquake for France are usually poorly constrained and mostly consist of sub-models of either pan-European or Caribbean models for respectively French mainland and Lesser Antilles territories. Even if those turnkey models produce first order estimation for quantifying the impact of an earthquake, they lack of in-situ studies to take into account the specificities of French territories on the overall workflow of modeling especially on hazard, vulnerability and loss estimation. Consequently, these models can’t be used with a high confidence in order to estimate the overall exposure of France in relation to not yet occurred but plausible earthquakes.

BRGM, as the French geological survey institute, and CCR, as the French State owned public reinsurance company, are both deeply concerned in a better understanding of the consequences of natural disasters occurring in France. Thus, since 2014, BRGM and CCR have been collaborating, amongst other projects, to develop a new consistent and reliable earthquake impact model for the French mainland and overseas territories covered by the specific French Natural Disasters Compensation Scheme.

This model encompasses a complete modeling chain from hazard to loss estimation. It consists in performing damage scenarios in order to evaluate the financial consequences for compensable insured property on buildings for a given seismic source, defined deterministically or probabilistically. To date, the model evaluates the consequences of seismic events for almost all kind of buildings in France: dwellings (houses and apartments), retail trade, professional and technical business services and industrial facilities. The seismic hazard is estimated deterministically for reference events by region but also probabilistically by generating stochastic earthquake dataset calibrated on the French seismic historical activity. Specific vulnerability assessments have been performed providing hazard to damage relationships specifically calibrated on French buildings.

The model can been used to estimate the consequences of real event such as the unusual M5.2 shallow earthquake occurred in November 2019 in France, providing fast estimation of its impact. The model, using the stochastic earthquake generator, allows us to estimate the exposure of French territories to earthquake providing indicators to support prevention actions led by the French government in the most exposed areas. Some of these indicators are already available throughout dedicated platform to insurances companies and public authorities and should be supporting State decision-makers and local authorities for prevention action such as retrofitting of buildings or adapting building codes.
Internal variability of surface solar radiation and associated PV production
Authors: Folini Doris
Published: March 2020

Results on the statistical properties of internal variability of annual mean surface solar radiation (SSR) and associated decadal scale trends are presented, following in part Folini et al. 2017 (doi:10.1002/2016JD025869). Estimates are based on 43 pre-industrial control (piControl) experiments of the Coupled Model Intercomparison Project Phase 5 (CMIP5). Trends are shown to depend strongly on geographical region and on whether they are quantified in absolute units or relative to the long term mean SSR. Providing one map for absolute and one map for relative trends is sufficient, as approximate analytical relations are shown to hold between trends of different length and likelihood and the standard deviation of the underlying SSR time series. Comparison with present-day observations and inter-model spread suggest an average uncertainty of these estimates of about 30%.  Intermodel spread suggests that regional uncertainties can be up to about three times larger or smaller. Using the model by Crook et al. 2011 (doi:10.1039/C1EE01495A) to translate SSR into PV production, associated internal variability of photo voltaic (PV) energy production is inferred. Results suggest that it is plausible for PV production to change by several per cent over a decade just because of internal variability.
The hydrological response of soil water storage capacity to human activities: A case study in the upper Yangtze River Basin, China
Authors: Zhang Xiaojing , Liu Pan , Xu Chong-Yu
Published: March 2020

The intensification of climate change and human activities can lead to non-stationarity of hydrological model parameters, which in turn affects the correctness of model simulation results. Previous studies mainly focus on impacts of climate change, while catchment hydrological responses to human activities require detailed investigation for sustainable water management. This study evaluates anthropogenic impacts on soil water storage capacity of the upper Yangtze River Basin by representing hydrological parameters as functions of human activity indicators. The Xinanjiang (XAJ) model is used since its parameter WM accounts for soil water storage capacity. In this study, time-variations of WM are identified by the split-sample calibration based on dynamic programming (SSC-DP). The variations are further related to ten indicators of human activities from five aspects: population, gross domestic product, farming, irrigation and reservoir construction. Then, the proposed WM functional form is selected by comparing the performance of a set of parameter functions of the identified human activity indicators during the validation period. The study shows that WM increases in 1976-2000, while a relatively high relationship is detected between WM and some indicators such as agricultural acreage, population and reservoir construction. It is further demonstrated that agricultural population has the greatest impact on soil water storage capacity and its linear functional form for WM is validated to be effective in 2001-2010 with best streamflow simulation, especially for low streamflow. These results can help understand the hydrological response to the increasing human development and contribute to adaptive development strategies for future water resource management.
Approximate expansions for water infiltration into dual permeability soils
Authors: Lassabatere Laurent , Di prima Simone , Iovino Massimo , Bagarello Vincenzo , Angulo-Jaramillo Rafael
Published: March 2020

The understanding of hydrological processes requires the investigation of preferential flows. In particular, the infiltration compartment is strongly affected by preferential flows. Recently, Lassabatere et al. (2014) proposed a model for the analytical modelling of the infiltration impacted by preferential flow. These authors extended the model developed by Haverkamp et al. (1994) for single permeability soils to the case of dual permeability soils. However, this model remains implicit, requiring an inversion procedure for the quantification of the bulk cumulative infiltration. Such an implicit feature prevents from direct computation and may annoy any fellow who wants a direct and simple computation procedure. In this paper, we develop two approximate expansions for both transient and steady states. For that, we use the expansions proposed by Haverkamp et al. (1994) for single permeability systems. These expansions are written for each compartment of the dual permeability soils, i.e. the matrix and the fast-flow regions and are combined for the computation of the bulk infiltration. After formulation of these expansions, these are assessed in terms of their capability to accurately reproduce the complete implicit model. Their validity time intervals are also determined and discussed. The main limitation for the use of these expansions results from the fact that the time intervals that define the transient and steady states are contrasted between the matrix and the fast-flow regions. However, some domain of validity can be defined allowing the use of these approximate expansions.

Haverkamp, R., Ross, P. J., Smettem, K. R. J. and Parlange, J. Y.: 3-Dimensional analysis of infiltration from the disc infiltrometer .2. Physically-based infiltration equation, Water Resour. Res., 30(11), 2931–2935, 1994.

Lassabatere, L., Angulo-Jaramillo, R., Soria-Ugalde, J. M., Simunek, J. and Haverkamp, R.: Numerical evaluation of a set of analytical infiltration equations, Water Resour. Res., 45, W12415, doi:doi:10.1029/2009WR007941, 2009.
Ecophysiological Responses of desert shrub to rainfall addition for Reaumurica soongorica in desert ecosystem
Authors: Li Wei , Zhang Cicheng
Published: March 2020

Desert environments are characterized by limited and highly variable rainfall, which is an intermittent source of water critical to the evolution of the structure and functioning of desert ecosystems. The present study was to assess the effects of different amounts of rainfall received through discrete rainfall events and of the ecophysiological responses for Reaumurica soongorica along multiple average precipitation (MAP) gradient. A field experiment was performed under seven simulated rainfall amounts (0 - 40 mm) with Reaumurica soongorica at respective High-P (120 mm), Middle-P (67 mm), and Low-P (35 mm) sites along middle and lower reach of Heihe River Basin in July, 2015. Pre-dawn plant water potential (ψpd), the rates of photosynthesis and stomatal conductance were measured synchronously. Results showed that: photosynthetic response of R.soongorica to rainfall pulse was significant different. The mean daily leaf gas exchange and maximum photosynthesis rate (Pn-max) of R.soongorica were decreased obviously with decreasing MAP. Vapour pressure deficit (VPD) was the predominant factor for gas exchange limiting. Under the control of VPD, stomatal conductance was pregressively reduced with decreasing ψpd, which was functioned as limiting Pn-max and further increasing water use efficiency (WUE). However, when MAP was declined below 35 mm, the response of stomatal conductance to ψpd was weakened, from which Pn-max began to increase again. 2 to 4 days hystereric response of R.soongorica ψpd to various rainfall events was found in High-P. Stomatal conductance was then increased linearly with increasing ψpd, from which Pn-max was also enhanced linearly. While weakly response of ψpd to similar rainfall events was observed in Low-P, where stomatal conductance and Pn-max was maintained stable after rain. Mentioned above, the effective rainfall pluse, induced by obvious physiological response of R. soongorica, was 3.63-6.73 mm and 6.73-10.09 mm for Linze and Ejina, respective. Our results provided comprehensively understanding in the consequences of long-term variability in rainfall for the physiology of desert plants and species dynamics in desert ecosystems.
Use of turbidity measurements to monitor suspended sediment loads on the Congo River
Authors: Mushi Catherine , Ndomba Preksedis Marko , Neal Jeffrey , Beya Jules , Trigg Mark
Published: March 2020

Recent mapping of sediment sources and erosion processes in the Congo basin show that sediment loads may be higher than previously estimated. Stark temporal changes in water turbidity in some of the tributaries observed by satellite images over the past 25 years indicate a need for closer monitoring of sediment load transported in the River. Turbidity sensors present an attractive option for sediment monitoring due to their ability to provide automated continuous time series data for estimation of suspended sediment concentration and suspended sediment fluxes in rivers; an attribute that is particularly important for remote rivers like the Congo. Continuous in-situ turbidity measurements were made using an OBS-501 turbidity sensor at the Kutu Moke monitoring site on the Kasai River, a major tributary of the Congo River between July 2018 and August 2019. The sensor infers turbidity by detecting the intensity of light scattered from suspended particles in water. We explore a field calibration of turbidity measurements with over 120 simultaneous suspended sediment concentration (SSC) measurements for the same period. Sediment loads estimated using high frequency turbidity data measurements (hourly) are then compared to loads estimated using classical sediment rating curves to establish if the turbidity provides a better representation of the suspended sediment load.
Regional differences in processes controlling Arctic sea ice floe size distribution in Chukchi Sea, East Siberian and Fram Strait during pre-ponding season
Authors: Wang Yanan , Hwang Byongjun , Basu Rajlaxmi , Ren Jinchang
Published: March 2020

The floe size distribution (FSD) is important to the physical and biological processes in the marginal ice zone (MIZ). The FSD is controlled by ice advection, thermodynamics (lateral melting), and dynamics (winds, tides, currents and ocean swell). These thermodynamic and dynamic conditions are different between the western Arctic (e.g., Chukchi and Beaufort Seas) and the eastern Arctic (e.g., Fram Strait). For example, the MIZ in the western Arctic is strongly influenced by a warm ocean due to enhanced sea-ice albedo feedback, while the MIZ in the eastern Arctic is strongly influenced by ocean swell. We hypothesise that this regional difference can affect the FSD differently between the two regions. To address the hypothesis, we analysed the FSD data derived the images from MEDEA and synthetic aperture radar (SAR) TerraSAR-X in Chukchi Sea, East Siberian Sea and Fram Strait. Our results show that the FSD in Chukchi Sea the most dynamic as it contains a larger percentage of smaller floes and undergoes a greater interannual variability in the FSD compared to East Siberian Sea and Fram Strait. In particular, the FSD in Chukchi Sea shows a notable change before and after 2012. This change is likely attributed to the severe storm occurred in early August 2012 and the presence of thinner ice in this region.
Spatial prediction of landslides for the Wanzhou District (China) applying a hybrid intelligent method based on random forest and cluster algorithms
Authors: Guo Zizheng , Yin Kunlong , Chen Lixia , Zhou Chao
Published: March 2020

In the Three Gorges Reservoir area of China, landslides have caused considerable losses of lives, environmental and social economy during the last decade. Hence, landslide susceptibility mapping is an urgent task that could help local decision makers in disaster risk assessment and management. This study aims at generating a regional landslide susceptibility map for the Wanzhou District in the Three Gorges Reservoir (China), based on random forest (RT) and cluster algorithms. Specifically, our objectives mainly include: (i) comparing the performances among different machine learning approaches, and (ii) validating the accuracy of a novel susceptibility reclassification method which used cluster algorithm. First, nine GIS-based thematic maps presenting landslide causal factors were prepared, including elevation, slope angle, aspect, lithology, land use, topographic wetness index (TWI), distance to rivers, distance to roads, and distance to geological structures. Total 441 landslides in a landslide inventory map were divided into two subsets: 75% landslides were used as training data, and 25% landslides were validation data. To establish the hybrid intelligent method, random forest was employed to calculate the landslide occurrence probability at every raster cell whereas the cluster algorithm was used to perform landslide susceptibility zonation. The analysis results of receiver operating characteristic (ROC) curve pointed out the prediction performance of random forest was 92.8%, better than that obtained from popular artificial neural network (ANN) (81.9%) and support vector machine (84.7%) models. Meanwhile, compared with traditional GIS-based reclassification methods, in the susceptibility zonation map obtained from cluster algorithm, more historical landslides distributed in the high susceptibility zones. Hence, the proposed approach is a promising tool for spatial prediction of landslides at the study area.
Uplift history of the Western Ecuadorian Andes: new constraints from low-temperature thermochronology
Authors: Margirier Audrey , Reiners Peter , Casado Ismael , Thomson Stuart , Alvarado Alexandra , Strecker Manfred
Published: March 2020

The Cenozoic growth of the Ecuadorian Andes has been strongly influenced by the compressional reactivation of inherited crustal anisotropies, strike-slip faulting and uplift, and the erosional effects of a wet tropical climate superposed on the deforming orogen. Some authors have linked uplift in the Western Cordillera to the interaction between the South American Plate and the subduction of the oceanic Carnegie Ridge. However, recent studies have alternatively suggested that the tectonic evolution of a northward-escaping crustal sliver in western Ecuador along the Pallatanga strike-slip zone may equally well explain mountain building and topographic growth in this region. While the importance of the Pallatanga Fault has been recognized in the context of seismic hazards, its long-term impact on the development of topography and relief has not been explored in detail. To evaluate the possible roles of oceanic ridge subduction and/or strike-slip motion in prompting the growth of the Western Cordillera, we present new thermochronological data to constrain the deformational history of the Western Cordillera at different latitudes. We focus on two sites in the vicinity of the Pallatanga strike-slip fault (3°S and 1°30’S) and a location farther to the north (0°30’N). Our apatite and zircon (U-Th-Sm)/He dates range from 26.0 ± 0.4 Ma to 3.9 ± 0.1 Ma and from 23.7 ± 0.3 to 5.9 ± 0.1 Ma, respectively. The three sampled sites record a clear age-elevation relationship. The inverse modeling of apatite and zircon (U-Th-Sm)/He dates and upcoming apatite fission-track data is expected to provide new constraints on the recent uplift and exhumation history of the Western Ecuadorian Andes and thus furnish information on the paleo-geographical evolution of the northern Andes.
Methane distribution at high spatial resolution in North Sea estuaries
Authors: Bussmann Ingeborg , Brix Holger , Fischer Philipp , Flöser Götz
Published: March 2020

Rivers are suspected to be a main suppliers of greenhouse gases (methane and carbon dioxide) to coastal seas, while the role of the interjacent tidal flats is still ambiguous. In this study we investigated the role of the Elbe and Weser estuaries as source of methane to the North Sea. We used high spatially resolved methane measurements from an underway degassing system and subsequent analysis with cavity ring down spectroscopy. Thus, a high-resolution representation of the methane distribution in surface waters as well as of hydrographic parameters was obtained for several cruises with two ships in 2019. For most areas, riverine methane was simply diluted by seawater, overlain by a strong tidal signal. However, on several occasions unexpectedly high methane concentrations were observed. Further detailed analysis will elucidate the role of riverine versus tidal impact on coastal North Sea methane fluxes.
Large variations in volcanic aerosol forcing efficiency due to eruption source parameters and rapid adjustments
Authors: Marshall Lauren , Smith Christopher , Forster Piers , Aubry Thomas , Schmidt Anja
Published: March 2020

The relationship between volcanic stratospheric aerosol optical depth (SAOD) and volcanic forcing is key to quantify the climate impacts of volcanic eruptions. In their fifth assessment report, the Intergovernmental Panel on Climate Change uses a single scaling factor between volcanic SAOD and effective radiative forcing (ERF) based on climate model simulations of the 1991 Mt. Pinatubo eruption, which may not be appropriate for eruptions of different magnitudes. Using a large-ensemble of aerosol-chemistry-climate simulations of eruptions with different SO2 emissions, latitudes, emission altitudes and seasons, we find that the effective radiative forcing is on average 21% less than the instantaneous radiative forcing, predominantly due to a positive shortwave cloud adjustment.  In our model, the volcanic SAOD to ERF relationship is non-unique and depends strongly on eruption latitude and season. We recommend a power law fit in the form of ERF = -15.1 × SAOD0.88 to convert SAOD (in the range of 0.01-0.7) to ERF.