bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of drone borne LiDAR technology for monitoring agricultural biomass and plant growth.
Authors: Trepekli Katerina , Westergaard-Nielsen Andreas , Friborg Thomas
Published: March 2020

With rising demand for increasing the yield potential of agricultural products and for reducing greenhouse gas emissions during food production, strengthening our scientific and technological capacity to monitor crop growth and above ground biomass (AGB) is indispensable to move towards more sustainable management of our agricultural resources. Pivotal to meet this goal is the application of high-throughput field-phenotyping tools such as drone borne Light Detection and Ranging (Lidar) systems for accurate, fine-grained, rapid and labor-saving measurements of vegetation growth parameters. Our objective is to develop and assess a workflow to estimate AGB, leaf area index (LAI), plant height (PH) and volume of a homogeneous and highly dense agricultural field using the capabilities of UAV-Lidar technology. The experimental site is located in Denmark and populated by potato plants. Aerial campaigns and field experiments, including destructive biomass sampling and measurements of LAI and plants’ geometrical characteristics at 1m2 square plots, were performed once per month during the vegetation growth period (May–September 2019). The high resolution (3.6 cm) Canopy Height model (CHM) is generated by first evaluating the performance of different filtering algorithms that separate the ground points from the Lidar-derived point cloud datasets. To extract the geometrical parameters of individual crop plants, we delineate the CHM by applying segmentation directly to the Lidar point cloud rather than segmenting the CHM as an interpolated raster surface. The PH obtained by the Lidar scanner is highly correlated with the field-measured PH (R²=0.89 and RMSE=0.028 m) implying that the point cloud data processing evaluated here is efficient and able to generate serviceably accurate CHMs for agricultural sites with similar vegetation structures. Throughout the observed vegetation growth period, the AGB can be quantified with high accuracy when it is considered to be a function of plant volume (R²=0.81 and RMSE=31.65 %) rather than a function of PH, as the latter approximating an exponential relationship with AGB. Height and density Lidar metrics were more effective in predicting in situ LAI measurements in comparison with remotely sensed LAI calculated directly from Lidar vegetation points following the Beer Lambert law. The predictive frameworks emerging from this approach indicate the applicability of drone borne Lidar systems for obtaining agricultural crop growth parameters in both high spatial and temporal resolution.
Six years of Swarm: instruments and data quality status
Authors: Qamili Enkelejda , Bouffard Jerome , Catapano Filomena , Siemes Christian , Miedzik Jan , Tøffner-Clausen Lars , Buchert Stephan , Trenchi Lorenzo , Stromme Anja , Vogel Pierre
Published: March 2020

The European Space Agency (ESA) Swarm mission, launched in November 2013, continue to provide the best ever survey of the geomagnetic field and its temporal evolution. These high quality measurements of the strength, direction and variation of the magnetic field, together with precise navigation, accelerometer, electric field, plasma density and temperature measurements, are crucial for a better understanding of the Earth’s interior and its environment. This paper will provide an overview of the Swarm Instruments and data quality status and product evolution after six years of operations, focusing on the most significant payload investigations to improve science quality, data validation activities and results along with future validation/calibration plans.
Visualizing transport of microplastic particles on soil surfaces with an advanced-imaging sCMOS camera
Authors: Klee Marcel , Laermanns Hannes , Müller Katharina Luise , Steininger Florian , Bogner Christina
Published: March 2020

The impact of microplastics in different ecosystems has recently become subject of numerous studies. However, the research of the last years has focused mainly on marine ecosystems and neglected terrestrial environments so far. This has led to a substantial lack of knowledge of the transport mechanisms of microplastic in soils and sediments. While first studies in this field investigate the abundance of microplastic in soils, only little is known about surface transport of microplastic particles.
The new approach of time-series analysis acquired by advanced scientific complementary metal–oxide–semiconductor (sCMOS) high-resolution cameras (Hardy et al., 2017, doi:10.1016/ j.catena.2016.11.005) could enhance the understanding of surface transport mechanisms of microplastic. We used a flume-box filled with different materials to trace the movements of fluorescent microplastic particles of 100 µm diameter under artificial irrigation. Furthermore, soil material from the German Wadden Sea was used to trace the run-off transport of microplastic in natural sediments. Here, we present first results on microplastic particle distribution, transport and accumulation as well on macroscopic as on microscopic scales.
A new working group on the Randolph Glacier Inventory (RGI) and its role in future glacier monitoring
Authors: Maussion Fabien , Hock Regine , Paul Frank , Rastner Philipp , Raup Bruce , Zemp Michael
Published: March 2020

The Randolph Glacier Inventory (RGI) is a globally complete collection of digital glacier outlines, excluding the two polar ice sheets. It has become a pillar of glaciological research at global and regional scales, among others for estimates of recent and future glacier changes, glacier mass balance, and glacier contribution to sea-level rise. After its creation in 2012, the dataset’s further development has been coordinated by an IACS Working Group (WG) until 2019. This new WG (2020 - 2023) expands the scope of the previous one with new and updated objectives.

The latest RGI version (V6) was released in July 2017, and several new glacier outline datasets have been generated by the community since then. In the past, the RGI was updated by an ad-hoc manual process, which was effective but labor-intensive. One of the main objectives of the WG is to automate this process as much as possible by incorporating RGI generation tools into the Global Land Ice Measurements from Space (GLIMS) glacier database. Furthermore, the RGI (as of version 6) needs further improvements  to remain useful to the wider scientific community. Examples include data quality (wrong/outdated outlines, ice divides) but also the quality and availability of glacier attributes (hypsometry, glacier type, ...). Additionally, there is a demand for consistent historic glacier outlines (e.g. from the mid-1980s or earlier) to facilitate validation of glacier evolution models or transient mass balance calculations. With this WG, we strive to continuously improve and update the RGI, as well as to lay out a long-term plan for sustainable continuation of the RGI beyond the end of this WG.

In this presentation, we will discuss the current status and future of the RGI, and will engage with the community to encourage participation and feedback.
Narrowing uncertainty on past and future human-induced warming using Kriging
Authors: Ribes Aurélien , Qasmi Saïd , Gillett Nathan
Published: March 2020

Using historical observations to constrain climate projections is an old idea. A variety of approaches, time periods and scales have been used to this purpose. Simultaneously, detection and attribution (D&A) methods have been developed to assess the contribution of subsets of forcings to historical changes, and have also been used to constrain projections. Here, we describe a unified statistical method to constrain the entire forced response pathway of global mean temperature using an adaptation of Kriging. We start by introducing this new statistical approach. Then, we derive consistent observationally-constrained estimates of attributable warming to date for various forcings, attributable warming rate, the response to various scenarios, Transient Climate Response (TCR), and Equilibrium Climate Sensitivity (ECS). Using revised observations of near-surface atmospheric temperature, we estimate a total forced warming of 1.19+/-0.15°C in 2019, with respect to the 1850-1900 baseline. Based on the newly available CMIP6 ensemble, we find that historical observations narrow uncertainty on past and future warming by about 50%, while evidence suggests that the proposed technique is not over-confident. Remarkably, both sides of uncertainty ranges are affected, leading to a 5–95% range for TCR of 1.44–2.35°C. We also compare and discuss the differences between the CMIP5 and CMIP6 ensembles. The proposed method is easily transposable, thus opening the possibility to monitor climate change and narrow uncertainty at the regional scale and/or for different climate variables.
Alleviation of an arctic sea ice bias in a coupled model through modifications of the subgrid scale orographic parameterization
Authors: Gastineau Guillaume , Lott Francois , Mignot Juliette , Hourdin Frederic
Published: March 2020

In the IPSL-CM6A-LR model, the subgrid scale orography (SSO) parameterization imposes at low level a blocked flow drag opposed to the local flow and a lift that is perpendicular to the local flow. We suggest that their tuning impacts of the Arctic sea ice coverage and the large scale oceanic circulation in climate models. In forced atmospheric mode, increasing the blocking and reducing the lift leads to an equatorward shift of the Northern Hemisphere subtropical jet, and a reduction of the mid latitude eddy-driven jet. It improves the simulated variability, with a reduced storm-track, and increased blocking frequency over Greenland and Scandinavia. Second, it contributes to cool the polar low-troposphere in winter. We show that the reduction in eddy activity yields a reduction of the poleward heat fluxes in the low troposphere of the mid-latitudes and polar regions. Transformed Eulerian Mean diagnostics also show that there is a reduction of the low-level eddy-driven subsidence in the polar region consistent with the simulated cooling. The changes are amplified in the coupled model, as the eddy-driven jet shift further south. The low-troposphere polar cooling is further amplified by the temperature and albedo feedbacks in link with the Arctic sea-ice. This corrects the warm winter bias and the lack of sea-ice that were present over the Arctic without changing the SSO parameters. This also impacts the ocean, with an equatorward shift of the Northern Hemisphere oceanic gyre, and a weakening of the AMOC.
Understanding catchment influences on flood generating processes - accounting for correlated attributes
Authors: Stein Lina , Clark Martyn , Pianosi Francesca , Knoben Wouter , Woods Ross
Published: March 2020

Understanding flood generating mechanisms is critical for model development and evaluation. While several studies analyse how catchment attributes influence flood magnitude and duration, very few studies examine how they influence flood generating processes. Based on prior knowledge about runoff behaviour and flood generation, we assume that flood processes depend not only on climate, but also on catchment characteristics such as topography, vegetation and geology. Specifically, we hypothesize that the influence of catchment attributes on flood processes will vary between different climate types. We tested our hypothesis on the CAMELS dataset, a large sample (671) of catchments in the United States. We classified 61,828 flood events into flood process types using a previously published location-independent classification methodology. Then we quantified the importance of both individual attributes (comparing probability distributions of different flood types) and interacting attributes (using random forests). Accumulated local effects allow interpretability of random forest with correlated attributes. Results show that climate attributes most strongly influence the distribution of flood generating processes within a catchment. However, other catchment attributes can be influential, depending on climate type. Based on the subset of influential catchment attributes, a random forest model can predict flood generating processes with high accuracy for most processes and climates, demonstrating capabilities to predict flood processes in ungauged catchments. Some attributes proved less influential than common hydrologic knowledge would suggest and are not informative in predicting flood process distribution.
Partial melting of an enstatite chondrite at 1 GPa: Implications for early planetary differentiation
Authors: Masotta Matteo , Folco Luigi , Ziberna Luca , Myhill Robert
Published: March 2020

We present new time series partial melting experiments performed on a natural enstatite chondrite (EL6), aimed at investigating the textural and geochemical changes induced by silicate-metal equilibration during early planetary differentiation. The starting material of our experiments consisted of small fragments (ca. 50 mg) obtained from the interior of the enstatite chondrite MCY 14005 (MacKay Glacier, Antarctica), collected during the XXX° Italian Expedition in Antarctica (PNRA). Experiments were performed in graphite capsules at a pressure of 1 GPa, at temperature ranging from 1100 to 1300 °C, with run durations from 1 to 24 h. The initial phase assemblage of the enstatite chondrite, mostly composed by granular enstatite and Fe-Ni metal (up to 400 µm in size) with minor amounts of sulphides and plagioclase, undergoes significant changes with increasing temperature and run duration. At 1100 °C, no silicate melt is produced and subsolidus reactions occur at the contact between the metal and silicate phases. At 1200 °C, small amounts of silicate melt are produced at the grain boundaries and enstatite grains in contact with the melt grow Fe-enriched rims. The metal portions are characterized by two immiscible liquid phases that exhibit rounded shapes when in contact with the silicate melt, whereas smaller (micrometric) liquid metal spheres occur isolated within the silicate melt throughout the experimental charges. These features are already observed in the 1 h experiment but become increasingly evident with increasing run duration, and at higher temperatures. In the experiments performed at 1300 °C, the amount of silicate melt increases and new silicate minerals form (olivine and low-Ca-pyroxene).

Enstatite chondrites are characterized by an oxygen isotope composition similar to that of the bulk Earth and Moon, and are considered to have initially formed in the terrestrial planetary zone of the solar nebula. For this reason, they represent a suitable material to investigate the early planetary differentiation processes that occurred in the proto-Earth system. Preliminary results from our experiments indicate that, at the investigated oxygen fugacity (1-2 log units below the IW buffer), the Fe-Si exchange between the metal and silicate phases allows the formation of silicate melt and silicate phases such as olivine and low-Ca-pyroxene. At the same time, the change in shape of the metal grains (increasingly circular/spherical with increasing temperature) and the overall reduction of their number density with increasing experimental time point to rapid aggregation of the metal phase and, possibly, to fast silicate-metal differentiation in small planetesimals.
Cultivation of Stropharia rugosoannulata on rice straw
Authors: jin zhi
Published: March 2020

Cultivation of Stropharia rugosoannulata on rice straw

 

Zhi Jin, Xue-Feng Hu

School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China

 

According to statistics, the annual output of crop straw in China attains more than 900 million tons. A C/N ratio of the straw of grass crops is too high to be bio-degraded rapidly when it returns to fields, adversely affecting the next rotation of crops. Therefore, the straw on the fields after harvesting is often treated with burning in China since the early history. The open-air burning, however, often causes the severe pollution of atmosphere, and has thus been forbidden by the Chinese government. However, the treatment of straw has become a headache problem since then. Stropharia rugosoannulata is one of the top ten mushrooms in the international mushroom market, as well as one of the important edible fungi recommended by the Food and Agriculture Organization of the United Nations to the developing countries. The rice straw, mainly composed of cellulose, hemicellulose, lignin, protein, resin and nutrient elements of Ca, P, K, Fe, Cu, Mn, Zn and Co, provides sufficient nutrients to Stropharia rugosoannulata. A field experiment was conducted to study the feasibility of growth of Stropharia rugosoannulata on fresh rice straw in the suburb of Shanghai after rice was harvested in late 2019. The cultured mycelia of Stropharia rugosoannulata were evenly sprinkled over fresh rice straw, and covered with a thin layer of soil and again with a layer of rice straw. The culture bed was kept at humidity of 70%-75% and temperature of 22°C-28°C. After two months, the sporophores of Stropharia rugosoannulata came out abundantly. This suggests that Stropharia rugosoannulata can grow and produce sporophores on fresh rice straw without addition of any organic manure. The sporophores of Stropharia rugosoannulata are treasures in food and highly enriched in human nutrients, with 25.75% of crude proteins, 2.19% of crude fat, 7.99% of crude fiber, 45.93% of carbohydrates and 16.72% of amino acids, as well as some antioxidants such as flavoniods, saponins and phenols. Moreover, the cellulose, hemicellulose and other non-biodegradable substance in rice straw were highly decomposed after the growth of Stropharia rugosoannulata, thus making it rapidly available to crops when returning to fields. With high content of organic matter and available nutrients, free of toxic heavy metals, the fungal-degraded rice straw is high-quality organic manure and will be chosen to be applied to the organic farming system in Shanghai in the future.
Strain localisation during diffusion creep: influence of grain coarsening and grain boundary sliding
Authors: Wheeler John , Evans Lynn , Gardner Robyn , Piazolo Sandra
Published: March 2020

Diffusion creep and the wet low temperature version, pressure solution, are major deformation mechanisms in the Earth. Pressure solution operates in many metamorphosing systems in the crust and may contribute to slow creep on fault surfaces. Diffusion creep prevails in areas of the upper mantle deforming slowly, and possibly in most of the lower mantle. Both mechanisms contribute to localisation since small grain sizes can deform faster.

However, there has been limited attention paid to the evolution of microstructure during diffusion creep. In some experiments grains coarsen; in some but not all experiments grains remain rather equant. We have developed a grain-scale numerical model for diffusion creep, which indicates that those processes are very important in influencing evolving strength. Our models illustrate three behaviours.

Strain localises along slip surfaces formed by aligned grain boundaries on all scales. This affects overall strength.

Diffusion creep is predicted to produce elongate grains and then the overall aggregate has intense mechanical anisotropy. Thus strength during diffusion creep, and localisation on weak zones, is influenced not just by grain size but by other aspects of microstructure.

Grain coarsening increases grain size and strength. Our most recent work shows how it interacts with ongoing deformation. In particular grain growth can lead to particular grain shapes which are directly related to strain rate, and influence strength. Consequently, understanding localisation during diffusion creep must encompass the effects of diffusion itself, grain boundary sliding and grain coarsening.
On the art of weighting an objective function with heterogeneous datasets
Authors: Pryet Alexandre
Published: March 2020

(Sub)surface hydrological models are more and more integrated, coupling multiple physical, biological and chemical processes. Such models are highly parameterized and most often, prior knowledge on these parameters is loose. Hopefully, such complex models may assimilate rich observation datasets, which constrain model parameters and reduce forecast uncertainties. The inclusion of diverse data types (aka “calibration targets”) within the so called “objective function” deserves particular attention to avoid bias in estimated parameters and forecasts of interest. In the most common approach, the fit between model outputs and data is described with a single objective function composed of the sum of weighted squared residuals between simulated values and their observed counterparts. When the residuals are statistically independent, homoscedastic and can be described with a gaussian probability distribution, the least square estimates obtained through the minimization of the objective function presents numerous advantages. However, when assimilating diverse data types with a model presenting structural error, the above-mentioned hypotheses on model residuals are at best very unlikely and in practice, never matched. Numerous studies investigated the interest of error modeling and data-transformation. Less attention has been paid to the integration of various data types (flows, heads, concentrations, soft data, ...) potentially spanning over several orders of magnitudes and originating from spatially distributed locations (wells, gaging stations, ...) each with contrasting sampling frequency (years, days, hours, ...). A purely formal statistical approach is challenging to put in practice, but the integration of such dataset into a single objective function deserves a relevant weighting strategy. Based on a synthetic model, different weighting strategies are compared based on their ability to reduce predictive bias and uncertainty. We propose an informal but practical formulation of the objective function that may be used for operational groundwater modeling case studies. The approach is eventually illustrated on a real-world case study.
Application of ATR-FTIR spectroscopy for the identification of chemical functional groups in kerogens and fossil resins.
Authors: Chen Yen Yu , Chang Ying Ju
Published: March 2020

Organic matters, such as oil, kerogen, fossil resins have different chemical functional groups. The complexity of chemical functional groups derives from the many sources of original contributing organic matter and long-term chemical and physical changes over geologic time. Fourier transform infrared spectrometer attenuated total reflectance (FTIR-ATR) can quantify the abundance of chemical functional groups and is a sensitive, high resolution and non-destructive analytical technique. The aim of this study was to characterize the spectral behavior and chemical structure of organic matters. In order to correlate organic matters of different types with its infrared spectra. The results show that FTIR-ATR spectra of oil contain intense aliphatic C-H stretching vibration in 2960 cm-1,2925 cm-1,2850 cm-1 region relative to the C–H (CH3) scissoring vibration at 1470 cm-1 and C=C aromatic ring stretching vibration at 1640 cm-1. We apply FTIR-ATR analyses for evaluating oil potential of kerogens. The longest aliphatic chains having the least amount of branching testifying to the highest oil generating potential. The similar locality of fossil resins has a similar chemical vibration ratio of C-H stretching (2925 cm-1,2850 cm-1) and C-H scissoring (1470 cm-1). In consequence, the analysis providing a rapid means of assessing organic matters and oil potential, and it can also rapidly identification the botanical origin of fossil resins.
River dunes under extreme high and low flows: outline of a research project
Authors: Lokin Lieke , Warmink Jord , Hulscher Suzanne
Published: March 2020

In the near future river discharges are expected to become more extreme due to climate change. Both high discharges and low discharges will occur more frequently and become more extreme (Klijn et al., 2015). While during high discharges bedforms grow and result in increased bed roughness resulting in higher flood levels. During extreme low discharges bed material may become immobile. Remaining bedforms are obstacles for waterborne transport, reducing the maximum load each vessel can transport.

Current dune models can describe the growth of the dunes and representative bedform related roughness under high flows and flood waves (Paarlberg et al., 2009). Also steps have been made to implement the processes leading to upper stage plane bed by adding suspended load transport (Naqshband et al., 2016). However, a model resolving the dune evolution though a full flood wave, including a falling stage towards extreme low flows with partly immobile bed, are not available yet.

The evolution of dunes during the falling stage of a flood wave, towards extremely low discharges, is not well understood and therefore cannot be properly predicted. Predictions of dune heights during periods of extreme low discharge can help fairway managers to maintain sufficient depth. To obtain this understanding first a fast dataset of bed level measurements, made by COVADEM on the Rhine river, will be analyzed with special focus on the growth and decrease of bedforms. This analysis will produce a set of parameters, valid for circumstances where immobile bed can occur and will lead to immobile bedforms. This new understanding of bedform development will be combined with the current knowledge on bedform development into an integrated model which can predict dune development from lower stage immobile dunes or flat-bed toward upper stage flat bed and vice versa.

References

Klijn, F, Hegnauer, M., Beersma, J. and Sperna-Weiland, F. (2015). Wat betekenen de nieuwe klimaatscenario’s voor de rivierafvoeren van Rijn en Maas? Samenvatting van onderzoek met GRADE naar implicaties van nieuwe klimaatprojecties voor rivierafvoeren. Deltares, KNMI, Ministerie van Infrastructuur en Milieuw (In Dutch)

Naqshband, S., van Duin, O., Ribberink, J., and Hulscher, S. (2016). Modeling river dune development and dune transition to upper stage plane bed. Earth Surf. Process. Landforms, 41: 323– 335. doi: 10.1002/esp.3789.

Paarlberg, A.J., Dohmen-Janssen, C.M., Hulscher, S.J.M.H. and Termes, A.P.P. (2009). Modeling river dune development using a parameterization of flow separation. Journal of Geophysical Research 114: F01014. DOI:2002JB001785/2007JF000910
Enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques from a 6-year LiDAR monitoring
Authors: Hartmeyer Ingo , Keuschnig Markus , Delleske Robert , Krautblatter Michael , Lang Andreas , Schrott Lothar , Otto Jan-Christoph
Published: March 2020

Abstract. Cirque erosion contributes significantly to mountain denudation and is a key element of glaciated mountain topography. Despite long-standing efforts, rates of rockwall retreat and the proportional contributions of low-, mid- and high magnitude rockfalls have remained poorly constrained. Here, a unique, terrestrial LiDAR-derived rockfall inventory (2011–2017) of two glaciated cirques in the Hohe Tauern Range, Central European Alps, Austria is analysed. The mean cirque wall retreat rate of 1.9 mm a−1 ranks in the top range of reported values and is mainly driven by enhanced rockfall from the lowermost, freshly deglaciated rockwall sections. Retreat rates are significantly elevated over decades subsequent to glacier downwasting. Elongated cirque morphology and recorded cirque wall retreat rates indicate headward erosion is clearly outpacing lateral erosion, most likely due to the cataclinal backwalls, which are prone to large dip-slope failures. The rockfall magnitude-frequency distribution – the first such distribution derived for deglaciating cirques – follows a distinct negative power law over four orders of magnitude. Magnitude-frequency distributions in glacier-proximal and glacier-distal rockwall sections differ significantly due to an increased occurrence of large rockfalls in recently deglaciated areas. In this paper we show how recent climate warming shapes glacial landforms, controls spatiotemporal rockfall variation in glacial environments and indicates a transient signal with decadal scale exhaustion of rockfall activity immediately following deglaciation crucial for future hazard assessments.
Modeling land surface processes over a mountainous rainforest in
Costa Rica using CLM4.5 and CLM5
Authors: Song Jaeyoung , Miller Gretchen R. , Cahill Anthony T. , Aparecido Luiza , Moore Georgianne W.
Published: March 2020

Abstract. This study compares the performance of the Community Land Models (CLM4.5 and CLM5) against tower and ground measurements from a tropical montane rainforest in Costa Rica. The study site receives over 4,000 mm of mean annual precipitation and has high daily levels of relative humidity. The measurement tower is equipped with eddy-covariance and vertical profile systems able to measure various micrometeorological variables, particularly in wet and complex terrain. In this work, results from point-scale simulation for both CLM4.5 and its updated version (CLM5) are compared to observed canopy flux and micro-meteorological data. Both models failed to capture the effects of frequent rainfall events and mountainous topography on the variables of interest (temperatures, leaf wetness, and fluxes). Overall, CLM5 alleviates some errors in CLM4.5 but CLM5 still cannot precisely simulate a number of canopy processes for this forest. Soil, air, and canopy temperatures, as well as leaf wetness, remain too sensitive to incoming solar radiation rates despite updates to the model. As a result, daytime vapor flux and carbon flux are overestimated, and modeled temperature differences between day and night are higher than those observed. Slope effects appear in the measured average diurnal variations of surface albedo and carbon flux, but CLM5 cannot simulate these features. This study suggests that both CLM models still require further improvements concerning energy partitioning processes, such as leaf wetness process, photosynthesis model, and aerodynamic resistance model for wet and mountainous regions.
Using wavelet transform and dynamic time warping to identify the limitations of the CNN model as an air quality forecasting system
Authors: Eslami Ebrahim , Choi Yunsoo , Lops Yannic , Sayeed Alqamah , Salman Ahmed Khan
Published: March 2020

Abstract. As the deep learning algorithm has become a popular data analytic technique, atmospheric scientists should have a balanced perception of its strengths and limitations so that they can provide a powerful analysis of complex data with well-established procedures. Despite the enormous success of the algorithm in numerous applications, certain issues related to its applications in air quality forecasting (AQF) require further analysis and discussion. This study addresses significant limitations of an advanced deep learning algorithm, the convolutional neural network (CNN), in two common applications: (i) a real-time AQF model, and (ii) a post-processing tool in a dynamical AQF model, the Community Multi-scale Air Quality Model (CMAQ). In both cases, the CNN model shows promising accuracy for ozone prediction 24 hours in advance in both the United States and South Korea (with an overall index of agreement exceeding 0.8). For the first case, we use the wavelet transform to determine the reasons behind the poor performance of CNN during the nighttime, cold months, and high ozone episodes. We find that when fine wavelet modes (hourly and daily) are relatively weak or when coarse wavelet modes (weekly) are strong, the CNN model produces less accurate forecasts. For the second case, we use the dynamic time warping (DTW) distance analysis to compare post-processed results with their CMAQ counterparts (as a base model). For CMAQ results that show a consistent DTW distance from the observation, the post-processing approach properly addresses the modeling bias with predicted IOAs exceeding 0.85. When the DTW distance of CMAQ-vs-observation is irregular, the post-processing approach is unlikely to perform satisfactorily. Awareness of the limitations in CNN models will enable scientists to develop more accurate regional or local air quality forecasting systems by identifying the affecting factors in high concentration episodes.
Skill of large-scale seasonal drought impact forecasts
Authors: Sutanto Samuel J. , van der Weert Melati , Blauhut Veit , Van Lanen Henny A. J.
Published: March 2020

Abstract. Forecasting drought impacts is still missing in drought early warning systems that presently do not go beyond hazard forecasting. Therefore, we developed drought impact functions using machine learning approaches (Logistic Regression and Random Forest) to predict drought impacts with a lead-time of 7 months ahead. The skill of the drought impact functions to forecast drought impacts was evaluated using the Brier Skill Score and Relative Operating Characteristic metrics for 5 Cases representing different spatial aggregation and lumping of impacted sectors. For German regions, impact functions developed using Random Forest show a higher discriminative ability to forecast drought impacts than Logistic Regression. Moreover, skill is higher for Cases with higher spatial resolution and less-lumped impacted sectors (Cases 4 and 5), with considerable skill up to 3–4 months ahead.
Stable water isotopes and accumulation rates in the Union Glacier region, Ellsworth Mountains, West Antarctica, over the last 35 years
Authors: Hoffmann Kirstin , Fernandoy Francisco , Meyer Hanno , Thomas Elizabeth R. , Aliaga Marcelo , Tetzner Dieter , Freitag Johannes , Opel Thomas , Arigony-Neto Jorge , Göbel Christian Florian , Jaña Ricardo , Rodríguez Oroz Delia , Tuckwell Rebecca , Ludlow Emily , McConnell Joseph R. , Schneider Christoph
Published: March 2020

Abstract. Antarctica is well known to be highly susceptible to atmospheric and oceanic
warming. However, due to the lack of long-term and in situ meteorological
observations, little is known about the magnitude of the warming and the
meteorological conditions in the intersection region between the Antarctic
Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic
Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the
northern edge of the WAIS. The firn core stable oxygen isotopes and the d excess exhibit no statistically significant trend for the period 1980–2014, suggesting that regional changes in near-surface air temperature and
moisture source variability have been small during the last 35 years.
Backward trajectory modelling revealed the Weddell Sea sector, Coats Land
and Dronning Maud Land (DML) to be the main moisture source regions for the study site throughout
the year. We found that mean annual δ18O (δD) values
in the UG region are negatively correlated with sea ice concentrations (SICs) in the northern Weddell Sea but not influenced by large-scale modes of
climate variability such as the Southern Annular Mode (SAM) and the El
Niño–Southern Oscillation (ENSO). Only mean annual d-excess values show a weak positive correlation with the SAM. On average annual snow accumulation in the UG region amounts to 0.245 m w.e. a−1 in 1980–2014 and has slightly decreased during this period. It
is only weakly related to sea ice conditions in the Weddell Sea sector and
not correlated with SAM and ENSO. We conclude that neither the rapid warming nor the large increases in snow
accumulation observed on the AP and in West Antarctica during the last
decades have extended inland to the Ellsworth Mountains. Hence, the UG
region, although located at the northern edge of the WAIS and relatively
close to the AP, exhibits rather stable climate characteristics similar to
those observed in East Antarctica.
Anti-reflexivity and logophoricity: an account of unexpected reflexivization contrasts
Authors: Varaschin Giuseppe
Published: March 2020

In this article, I will provide an account of unexpected reflexivization contrasts (URCs) which have been problematic for analyses of English reflexives since the early days of Generative Grammar (Jackendoff 1969; Postal 1968; Lakoff 1968). These contrasts were the main motivation for introducing thematic conditions on reflexivization (Jackendoff 1972; Wilkins 1988). I will argue that thematically-based accounts are empirically inadequate and that, when the reflexivity-and-chains approach of Reinhart & Reuland (1993) is paired with an enriched conception of compositionality and a theory of logophoric discourse roles, the problem of URCs can be reduced to the more tractable problem of logophoric reflexives. This, however, requires that logophoric reflexives be seen not as exempt, but as tolerable violations of Condition A (Menuzzi 1999). I will argue that these violations, under adequate circumstances (e.g., when they occur within anti-reflexive predicates), give rise to logophoric interpretations. The unexpected reflexivization contrasts turn out to be a byproduct of the particular animacy requirement logophoric expressions place on their antecedents.
Editorial
Authors: Vigil Carlos Humberto
Published: March 2020

De acuerdo con nuestra actual Ley de Educación Superior, en su artículo 2, la educación superior integra tres funciones: La docencia, la investigación y la proyecci6n social, definiendo la investigación como la búsqueda sistemática y el análisis de nuevos conocimientos para enriquecer la realidad científica y social.
Presencia y concentración de flúor en las marcas de sal distribuidas en El Salvador
Authors: Girón Alvarez Beatriz Eugenia , Márquez Hernández Rhina Violeta , Sermeño Camacho Karla Judith
Published: March 2020

En este estudio de tipo descriptivo, se analizaron 25 muestras de sal obtenidas en los diferentes supermercados, mercados y tiendas de la ciudad de San Salvador. Los análisis químicos de cuantificación de flúor se realizaron en el Laboratorio de Control de Calidad Fisico-Quimico de Medicamentos, Cosméticos y Alimentos del Centro de Investigación y Desarrollo en Salud (CENSALUD), de la Universidad de El Salvador. Con el método de potenciometría por media del aparato electrodo ion específico para flúor marca CRISON, se determine' la concentración del contenido de flúor en cada una de las muestras, dando como resultado un valor en milivoltios. Estos valores, a través de cálculos posteriores se transformaron a una cuantificación en partes por millón mediante una curva patrón previamente obtenida con concentraciones conocidas de flúor (estándares de calibración de Flúor de 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm y 100 ppm) utilizando el método de regresión lineal. La clasificación y análisis de los resultados obtenidos en este estudio se basaron en los valores de flúor en la sal recomendados por la Organización Mundial de la Salud (OMS) los cuales oscilan en un rango de 180 a 220 ppm. Tomando en cuenta esta información, los análisis mostraron que, de las 26 muestras analizadas, 21 se ubicaron por debajo del nivel recomendado por la OMS y los 5 restantes excedieron dicho rango.
Aulas alternativas. Una estrategia de atención educativa a niños y niñas de la zona rural del departamento de la Libertad
Authors: Navas Hurtado Victor Manuel , Pérez Cruz Blanca Margarita , Sermeño Rubén Regalado
Published: March 2020

Aulas Alternativas de Educación Básica en nuestro país, es el nombre que se le ha dado por parte del Ministerio de Educación., a una estrategia de atención educativa, por un solo maestro(a) a dos o más grados que tienen baja matricula en la zona rural y que trabajan en forma simultánea en la misma aula o salón de clase, y a la vez en forma separada por pertenecer los niños y niñas a diferentes grados; fue iniciada en 1996 por el Programa EDUCO. Esta estrategia se apoya en instrumentos curriculares conocidos como Unidades de Aprendizaje. La investigación realizada a finales de 1999 y principios de 2000, tuvo como objetivo evaluar si la aplicación de la estrategia educativa de aulas alternativas contribuye a lograr la calidad del proceso de enseñanza aprendizaje. Se analizó la forma como se realiza la practica educativa en seis escuelas del Departamento de La Libertad que cuentan con las Aulas Alternativas; se determine cuan cerca o lejos se aplica la estrategia de lo planteado por el Ministerio de Educación. Los resultados cuentan con la validez posible y necesaria para que puedan servir de base para revalorar los diferentes aspectos que integran esta estrategia. La estrategia de Aulas Alternativas no se aplicaba totalmente en las Aulas Alternativas en el momento del estudio; entre las Aulas Alternativas y las Regulares no se encontró mayores diferencias en la calidad educativa, cuando en aulas alternativas trabajan con las Unidades de Aprendizaje, predomina el trabajo de grupos, el trabajo ex aula era más frecuente en las Aulas Alternativas al igual que la participación de los diferentes actores del proceso. Entre las conclusiones más significativas del análisis de las Unidades de Aprendizaje, se citan: presentación escrita y grafica muy buena en un 80%, no hacen diferencia entre una actividad básica, practica o de aplicación; no se visualiza graduación en las exigencias de las actividades de aprendizaje; hay contradicción en algunas actividades, algunos contenidos tenían mas enfoques hacia lo urbano que rural, entre otras.
Diagnóstico social para la ejecución de un programa de alfabetización, aprendizaje de oficios y su contribución en la satisfacción de las necesidades básicas
Authors: Mendoza de Yánez Alicia Esperanza
Published: March 2020

De acuerdo a la Constitución de la Republica (1983) la educación básica en El Salvador es una necesidad que debe ser atendida de forma gratuita para todos los ciudadanos. A pesar de las estrategias de ampliación de cobertura y mejora de calidad aun el índice de analfabetismo entre Ia población de 15 años y más asciende a 34.38% en forma general, incrementándose en el área rural donde alcanza un 39.20% y es ahí donde se concentra el 45% de In población con los niveles más bajos de ingreso; por lo que In mayoría de hogares están en situación de pobreza y pobreza extrema. El objetivo principal fue elaborar un diagnóstico de necesidades para implementar Ia estrategia de intervención más adecuada que contribuyera a in satisfacción de las necesidades básicas de una parte de la población del cantón San José las Flores del municipio de Tonacatepeque, al norte del departamento de San Salvador. La muestra fue de 125 personas analfabetas voluntarias para aprender a leer y escribir y aprender un oficio. Esta investigacion-action, se base; en dos principios fundamentales: el de auto-defensa activa y el de auto­abastecitniento económico. En el estudio realizado en el Último semestre del año 2004, se obtuvo que del total de in población el 58% de personas lograron aprender a leer y escribir; un 62% alcanzo un aprendizaje normal de un oficio. Estas personas Llegaron a la conclusión que solo trabajando en conjunto y ayudándose mutuamente puede dársele solución a muchos problemas. Se deben realizar más intervenciones sobre alfabetización y aprendizaje de oficios, to que permitir responder satisfactoriainente a las necesidades básicas de In población.
HYPOGENE ALUNITE FROM THE EL SALVADOR DISTRICT, CHILE, INDICATES POTENTIAL FOR A BLIND PORPHYRY COPPER CENTER
Authors: Hedenquist Jeffrey W. , Watanabe Yasushi , Arribas Antonio
Published: March 2020

Surface samples of hypogene alunite that cement late breccia bodies from the El Salvador porphyry copper district of Chile were recently dated. One alunite sample over the principal Turquoise Gulch porphyry deposit has a 40Ar/39Ar total gas age of 40.64 ± 1.04 Ma, overlapping the age of a late latite intrusion. Two other samples associated with quartz-alunite replacement of rhyolite, ~750 m southwest of the collapse zone over the block cave of the porphyry copper deposit, are distinctly younger, at 38.12 ± 0.66 and 38.04 ± 0.22 Ma (averages of duplicate analyses, with ±2σ errors).

Previously reported U/Pb ages of zircons from 15 Eocene-age diorite, granodiorite, and granite porphyry intrusions have weighted mean ages that range from about 44 to 41 Ma, with peak magmatic flux interpreted at 44 to 43 Ma. Porphyry copper ores in the El Salvador district formed at about the same time as porphyry intrusions, with intrusive centers that migrated in a south-southwest direction, from the small deposits at Cerro Pelado (~44.2 Ma), to Old Camp (~43.6 Ma) and M Gulch-Copper Hill (~43.5–43.1 Ma), to the main ore deposit at Turquoise Gulch (~42 Ma). The granodiorite porphyry intrusions at Turquoise Gulch are associated with ~80% of the known copper ore of the district; they record waning stages of magmatism at 42.5 to 42.0 Ma, followed by weakly altered latite dikes at 41.6 Ma. Molybdenite in quartz veins returned Re-Os ages of 41.8 to 41.2 Ma.

The two alunite samples from our study with coincident dates of ~38 Ma provide evidence for magmatic-hydrothermal activity younger than any recognized to date, consistent with the alteration overprint of quartz-alunite on older muscovite after erosion. This younger activity must have been associated with a blind intrusion, likely located south of the Turquoise Gulch deposit, based on the distribution of alteration minerals, and offset from the zoning associated with the Turquoise Gulch center. Stable isotope values (δ34S, δ18O, δD) of the ~38 Ma alunite indicate a high-temperature hypogene origin, consistent with formation in a lithocap environment that typically is located at shallow levels over and on the shoulders of porphyry copper deposits. Both observations—alteration overprint and markedly younger age of alunite—indicate the potential for porphyry copper mineralization south of Granite Gulch, as much as 1,000 m below the level of the coeval outcropping quartz-alunite replacement, perhaps near ~2,000-m elevation; this is hundreds of meters deeper than the known copper ore of Turquoise Gulch.
Designing Cluster Plots for Sampling Local Plant Species Composition for Biodiversity Management
Authors: Quon Christie , Lam Tzeng-Yih , Lin Ho-Tung
Published: March 2020

Aim of study: Cluster plot designs are widely used in national forest inventory systems to assess current forest resources. By spreading subplots apart, a cluster plot could potentially capture a large variety of local plant species. This aspect has rarely been examined in the past. This study is conducted to understand how design factors of a cluster plot affect estimates of local plant species composition.Area of study: Two large census forest plots in Taiwan and Peninsular Malaysia over 25 ha with different species richness were used.Material and methods: Design factors of a cluster plot were plot configuration (PCONFIG), plot area (PAREA), cluster layout (CLAYOUT), and extent of ground area covered by a cluster (CEXTENT). Jaccard and Sørensen similarity indices were used to compare species compositional similarity between two cluster plot designs. A simulation study was carried out.Main results: Results were consistent among the study sites and similarity indices. PAREA, CLAYOUT, and CEXTENT notably influenced how species composition was sampled. Larger PAREA increased similarity in species composition between two cluster plot designs. Square and rectangle CLAYOUT had the most dissimilar species composition between them. Larger CEXTENT decreased similarity in species composition.Research highlights: We recommend that for CEXTENT ≤ 1000 m2 and PAREA ≤ 500 m2, a cluster plot of rectangle CLAYOUT is preferred for information gain. The study could potentially benefit forest managers designing cluster plots for plant diversity assessment.Keywords: Biodiversity assessment; composition similarity; national forest inventory; species diversity; sampling design; sampling efficiency.Abbreviation used: extent of ground area covered by a cluster (CEXTENT); cluster layout (CLAYOUT); Jaccard similarity index (JAC); plot area (PAREA); plot configuration (PCONFIG); Sørensen similarity index (SOR).