bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sea Ice Tracking System (SITU): A Community Tool for the Arctic and Antarctic
Authors: Tremblay Bruno , Pfirman Stephanie , Campbell Garrett , Newton Robert , Meier Walt
Published: March 2020

The Sea Ice Tracking System (SITU), formerly known as the IceTracker or Lagrangian Ice Tracking System, has been expanded to include new functions facilitating a wide range of new applications (http://icemotion.labs.nsidc.org/SITU/). Ice motion vectors are calculated from an optimal interpolation of satellite-derived, free-drift and buoy drift estimates (Polar Pathfinder dataset, version 4, https://nsidc.org/data/nsidc-0116; International Arctic Buoy Program, http://iabp.apl.washington.edu/; NCEP/NCAR reanalysis, https://www.esrl.noaa.gov/). SITU now calculates forward and backward trajectories of Antarctic as well as Arctic sea ice from 1979 to 2018 and incorporates basin-wide contextual information including timeseries of bathymetry, ice concentration, ice age, ice motion, air temperature, pressure, and wind speed, along the tracks. A new animated background option allows users to visualize these basin-wide changing environmental conditions as the tracking progresses. SITU can be used by researchers, educators, local and indigenous communities, policy and planning professionals, and industries.  For instance, geologists can use SITU to determine the provenance of sediment transported by sea-ice and deposited at an ocean core site; biologists can identify source region of biomass transported by sea-ice and seeding algal bloom in a given sea, or overlay bear and birds tracks over ice conditions or ice types animated in the background; coastal communities can backtrack ice to reveal age, origin and other factors that influence habitats of ice-associated species; people planning future expeditions can review recent ice conditions along potential cruise tracks, historians can compare current air temperatures, wind conditions, and ice concentration with past expeditions; students can learn about sea ice motion in the Arctic or compare recent ice drift (Tara or MOSAIC) with that of the epic expedition of Nansen. A new Eulerian option allows users to see changing conditions at one point over the full satellite record (1978 to present). This Eulerian depiction reveals variability as well as trends, and can provide context for data retrieved from a mooring, sediment trap, or sediment core. Publically hosted on the NSIDC Labs webpage, data can be downloaded graphically or in spreadsheet format for deeper analysis.
Dynamic retrieval of informative inputs for multi-sector reservoir policy design with diverse spatio-temporal objective scales
Authors: Zaniolo Marta , Giuliani Matteo , Block Paul , Castelletti Andrea
Published: March 2020

Advances in monitoring and forecasting water availability at various time and spatial scales offer a cost-effective opportunity to enhance water system flexibility and resilience. By enriching the basic information system traditionally used to design reservoir operating policies (i.e., time index and reservoir storage) with additional inputs regarding future water availability, operators can better anticipate and prepare for the onset of extreme hydrologic conditions (wet or dry years). Numerous candidate hydro-meteorological variables and forecasts may potentially be included in the operation design, however, and the best input set for a given problem is not always evident a priori. Additionally, for multi-purpose systems, the most appropriate information set and policy shape likely changes according to the objective tradeoff. 
In this work, we contribute a novel Machine Learning approach to link an Input Variable Selection routine with a multi-objective Direct Policy Search framework in order to retrieve the best policy input set online (i.e., while learning the policy) and Pareto-dynamically. The selected policy search routine is the Neuro-Evolutionary Multi-Objective Direct Policy Search (NEMODPS) which generates flexible policy shapes adaptive to changes in the policy input set. This approach is demonstrated for the lower Omo River basin, in southern Ethiopia, where regulation of the recently constructed Gibe III megadam must strike a balance between hydroelectricity generation, large scale irrigation, and ecosystem services downstream.
We develop a dataset of candidate policy inputs comprising streamflow and precipitation forecasts at multiple spatial and temporal scales, from days to months ahead. Long term (season-ahead) forecasts are conditioned on well-recognized climatic oscillations in the region. Specifically, Artificial Intelligence tools are used to detect relevant anomalies in gridded global climatic datasets of sea-surface temperature, sea-level pressure and geopotential height, which are used as predictors for a multi-variate non-linear forecast model.  Moreover, we analyze how varying objectives – and tradeoffs therein – benefit from different information.
Results suggest that informing water system operations with appropriate information can reduce conflicts between water uses, especially in extreme years when a basic policy is particularly inefficient.
Overriding-plate deformation during micro-continent accretion
Authors: Erdős Zoltán , Huismans Ritske S. , Faccenna Claudio
Published: March 2020

Both divergent and convergent plate boundaries had been studied extensively throughout the last five decades. Among a host of other aspects came the realization, that given the right circumstances, a broad extensional basin can form behind a convergent plate boundary. The exact mechanisms triggering back-arc extension and why they are episodic, lasting only for tens of millions of years is still debated. The absolute and relative velocities of the plates, the age of the subducting oceanic plate and the inherited rheological properties of the back-arc lithosphere are all thought to be key players, shaping the dynamics of the fore-arc - back-arc systems.

Here we use 2D mantle scale plane-strain thermo-mechanical model experiments to investigate how the accretion of small continental crustal terrains onto the overriding plate affect the dynamics of the subducting slab and the deformation of the overriding plate.

Our results suggest that slab-retreat and back-arc extension can be achieved through the combination of slow convergence and micro-continent accretion. Back-arc extension during fast convergence is also possible through the subsequent accretion of more than one micro-continental terrain. Moreover, even the accretion of one such terrain can produce short (1-5 My) episodes of extension-contraction-quiescence in the overriding plate. These episodes are connected to slab break-off events, slab-interaction with upper mantle phase-change boundaries and variations in slab-pull due varying slab thickness.

Our model experiments also result in complex structures in the overriding plate where discrete outcrops from a single oceanic basin are preserved on the surface hundreds of kilometres apart. This indicates that in nature a simple accretion scenario could produce a surface geological record that is difficult to decipher. Our results compare favourably to observations from the Aegean back-arc basin.
Delimitating functional zones at municipal or county level in China based on a spatial optimization and simulation coupling approach
Authors: Li Dan , Qiao Jigang , Zhang Yihan
Published: March 2020

Territory spatial planning is a guide and blueprint for future territorial development in China. It means to form a scientific, rational, intensive, and efficient spatial protection and development pattern in territory space. The first task according to the government is to delimitate the functional zones of ecology, agriculture, urban zones, and delineation of ecological protection red lines, permanent basic farmland boundaries, and urban development boundaries ("three zones and three lines"). Currently China used a resource and environment carrying capacity and land space development suitability evaluation ("double evaluations") to complete the delimitation task. However, the process of these evaluations and demarcation is relatively complicated, high-level human intervention, and the operability is not strong, therefore it is not practically at municipal or county level. We proposed a new delineation framework, methods, and software tools for the delimitation work, based on a spatial optimization and simulation coupling approach, and is verified by an example in Guangzhou, a super metropolis city in China. It shows that this method can rapidly and efficiently delimit urban ecological and agricultural zones based on regional geographic background conditions, by using an ant colony intelligent optimization algorithm, and using a cellular automata model to delineate compact urban zones. Compared with the "three zones" division plan in the "Guangzhou Land and Space Master Plan (2018-2035) Draft" which is published by local government, the delimitated functional zones by proposed method can meet the quantitative requirements of the draft, while providing more detailed and realistic spatial pattern of the three functional zones, which can be very useful for municipal and county level territory spatial planning work.
Unrest episodes at Alcedo and Cerro Azul (Galapagos) revealed by InSAR data and geodetic modelling
Authors: Galetto Federico , Hooper Andrew , Bagnardi Marco
Published: March 2020

Western Galápagos calderas experienced repeated eruptive and non-eruptive unrest in the last decades, only partially studied. Here we investigated, using the Synthetic Aperture Radar Interferometry (InSAR) and geodetic modelling, the eruptive and the non-eruptive unrest episodes occurred in two of the less studied calderas of the western Galápagos: Alcedo and Cerro Azul. Alcedo underwent repeated non-eruptive unrest from 2007 to 2011, while Cerro Azul experienced an unrest, from 2007 to 2008, culminated in two eruptive phases from May 29th to June 11th 2008. Results highlight how Alcedo experienced two episodes of uplift due to new magma injections in its shallow magma reservoir, separated by an episode with a limited lateral propagation of magma, probably interrupted for the lack of new magma supply in the magma reservoir. Results also hint to a possible relationship between these short-term unrest episodes and the longer-term process of resurgence at Alcedo. As for Cerro Azul, we overcame unwrapping errors affecting some of the InSAR data of Cerro Azul by proposing a new method, based on the wrapped phase differences among nearby pixels, to invert the wrapped phase directly. Our results highlight how the eruption was preceded by long-term pre-eruptive inflation (October 2007 – April 2008). During the first eruptive phase, most of the magma responsible for the inflation fed the lateral propagation of a radial dike, which caused a first deflation of the magmatic reservoir. During the second eruptive phase, the further lateral propagation of the dike fed a radial eruptive fissure at the base of the edifice, causing further deflation of the magmatic reservoir. From the first to the second eruptive phase, the radial dike changed its strike propagating towards a topographic low between Cerro Azul and Sierra Negra. An increase in magma supply from the reservoir to the dike promoted the further lateral propagation of the dike, confirming the importance of a continuous supply of magma in the propagation of a dike. 
Application of QMRA to MAR operations for safe agricultural reuse and marine recreational impacts in coastal areas
Authors: Masciopinto Costantino , Vurro Michele , Lorusso Nicola , Santoro Domenico , Haas Charles N.
Published: March 2020

The Municipality of Fasano (Puglia, Italy), i.e. owning one of 32 managed aquifer recharge (MAR) sites in operation in the Puglia region, has pioneered the reuse of tertiary-treated municipal effluent for both soil irrigations and the containment of seawater intrusion via groundwater recharge by ditches.

In this work, quantitative microbial risk assessment (QMRA) methodologies have been applied to assess the degree of safety associated with such integrated practices by assessing the risks for public health resulting from the exposure to the reclaimed water. Escherichia coli (E.coli) dose-response model was used in this work since the pathogenic E.coli is reported to potentially occur in reclaimed water obtained from treated municipal effluents. The target count of pathogens ingested during swimming or inoculated by contaminated (uncooked) vegetables and fruits, was determined from the Monte Carlo Markov Chain (MCMC) Bayesian procedure applied to the results obtained from a monitoring campaign carried out in 2019. An optimization routine was applied in order to determine the most probable target pathogen count by minimizing the number of water samplings. The monitoring positions along the coast were defined by means of mathematical modeling, which highlighted the preferential pathways followed by pathogens when released into the fractured aquifer at a recharge operation flow rate of 10-30 L/s.

QMRA results indicated a negligible risk impact (12% probability of 0.4 infections per year) for soil irrigation practices and no impact on the seawater quality as a result of the additional treatment barrier provided by the so-called "soil-aquifer treatment" during the pathogen transport through the fractures of groundwater.

 
Application of Raman spectroscopy for understanding the mineralogical composition of ancient copper slags (Timna, Israel)
Authors: Culka Adam , Natherová Vendula , Jehlička Jan , Ettler Vojtěch
Published: March 2020

Prehistoric slags (Late Bronze Age to early Iron Age, ca. 1300 – 1000 BC) from copper metallurgy were sampled at the archaeological site no.2 in Timna, Israel. A classical combination of analytical methods for this kind of samples (optical and scanning electron microscopy, X-ray diffraction analysis, and electron microprobe analysis) was complemented with Raman microspectroscopy.

Raman microspectroscopy is a strong tool for phase or mineral identification in general, and when coupled with the methods for determination of the chemical composition such as electron probe microanalysis, it provides a comprehensive phase description of the sample. Slags are generally composed of both crystalline and amorphous glass-like phases and include metals, intermetallic compounds and alloys, sulfides, oxides, silicates, silicate glasses and carbonaceous fuel residues. With the exception of pure metals and their respective alloys, all these phases can be theoretically analyzed using Raman microspectroscopy. However, laser-induced fluorescence can become a major issue, owing to a presence of many different metallic elements. Selection of appropriate laser excitation wavelength can reduce the amount of fluorescence. Using Raman microspectroscopy it was possible to identify major silicate phases such as olivine (fayalite) and clinopyroxene (hedenbergite). Using this technique the crystallinity of iron oxides was identified and magnetite and hematite were differentiated. Despite the fact that Cu sulphides have simple Raman spectra with only few diagnostic bands, digenite and chalcopyrite were confirmed in the Timna slags. This study was supported by the Czech Science Foundation project (GAČR 19-18513S). The sampling campaign was carried out in the framework of Erasmus+ Mobility exchange programme between Charles University, Prague, Czech Republic (CUNI) and Hebrew University in Jerusalem, Israel (HUJI).   
Natural and induced radioactive nuclides in the soils of forest and long fallow lands of the background and polluted territories of Kaluga region of the Russian Federation.
Authors: Kononets Olga , Shcheglov Alexey , Tsvetnova Olga
Published: March 2020

The level of contamination with the natural (K-40, Th-232, Ra-226) and induced (Cs-137) radioactive nuclides of the following forest soils(pine- trees, fir-trees, birch-trees) and of the long fallow ecological systems at the polluted (southern part) and not polluted (northern part) territories of Kaluga region of the Russian Federation, was evaluated in 2017. The analysis showed that the specific activity of the natural radioactive nuclides Ra-226 and Th-232 is low and it changes insignificantly in the soils' profile of the studied ecological systems. Higher levels of K-40 are registered, reaching the maximum in the long fallow soils, which arises from a heavier granulometric composition of the differences that were formed here. In general the density of soil contamination with the natural radioactive nuclides in various ecological systems varies: 3,14-11,70 for Ra-226, 0,33-3,22 for Th-232 and 3,52-94,19 kBq/m2 for K-40, which corresponds to the background indexes  and complies with the regional lithological features of the territory. The density of the soils contamination with Cs-137 varies from 60.8 to 273,8 kBq/m2 at the polluted territories(it does not exceed 3 kBq/m2 at the background territories). Among the studied ecological systems the forest ones (especially coniferous) are the most contaminated with Cs-137, the long fallow ecological systems are the least contaminated with Cs-137. In comparison with the initial period starting with the precipitation in 1986, the density of soils' contamination with Cs-137 has presently decreased by more than 3 times in average. However this index still significantly exceeds the admissible level of 37kBq/m2. Cs-137contributes most significantly into the summary specific activity of the soils and gives the power of the  equivalent absorbed dose for the  ecological systems of the polluted territories. K-40 provides this effect for the background territories.
Abiotic and biotic drivers of ecosystem development – results from Chicken Creek Catchment
Authors: Gerwin Werner , Schaaf Wolfgang
Published: March 2020

15 years of initial ecosystem development have been observed in the artificial Chicken Creek Catchment in Eastern Germany (State of Brandenburg). The 6 ha site was constructed in 2004/05 as a watershed within a post-mining landscape and was left for an unmanaged primary succession. The number of plant species increased quickly during the first years parallel to an increasing groundwater table within the catchment. In 2014 a total of about 180 vascular plants were identified in this young ecosystem.

During its development vegetation differentiated according to morphological and soil related conditions. The semiaquatic part around a small pond developed differently compared to the upper, terrestrial part. In this terrestrial part Robinia pseudoacacia L. early occurred as a pioneer tree species. Large surface areas, however, remained open land areas without tree or shrub vegetation. Robinia as a N-fixing tree species accumulates nitrogen in its litter layer at the soil surface which influences the further vegetation development in these parts of the catchment.

Furthermore, Robinia together with other tree species contributed obviously to a significant groundwater lowering in the constructed catchment area. This decrease of the groundwater tables in the study area was intensified by two extremely dry summer seasons (2018 and 2019). As a result, the overall composition of the vegetation in the terrestrial part of the catchment changed slightly indicating dryer conditions particularly for herbaceous plants.

Initial abiotic site conditions (geomorphology and soil conditions) in combination with external abiotic drivers (amount of precipitation) shaped the development of plant communities. Vice versa, the occurrence of plant species with specific functionality (N-fixation and high water consumption) contributes to a further spatial differentiation of the vegetation composition. The constructed Chicken Creek catchment as an artificial landscape unit allows for detailed insights into these ecological differentiation processes of the initial developmental ecosystem phase.
Comparison of paradigmatic gravity wave models for ocean and atmosphere
Authors: Harlander Uwe
Published: March 2020

It appears that oceanographers and meteorologists have different pictures in their minds when they speak about internal waves. The reason might be that in both communities different paradigmatic gravity wave models based on different simplifying assumptions are in use.  For the oceanographer, internal wave beams are rather common, a feature virtually unknown to the atmospheric scientist.  In contrast, wave packets traveling upwards in the atmosphere is the standard picture for the meteorologist.  The mathematical origin of such a different view is that for time harmonic waves, the underlying boundary value problem for internal waves in the ocean is hyperbolic but elliptic for atmospheric flows.

In the present paper we discuss the consequences that result from these two different types of boundary value problems. Wave focusing is a rather 
generic process for hyperbolic problems and we argue that the latter should also be of interest to meteorologists in view of new findings that indeed 
a significant part of the internal waves in the atmosphere travel downward. We further apply some of our findings to new laboratory data on inertial modes arguing that an additional shear flow leads to an elliptic boundary value problem and beam-like wave fields, typical for the inertial waves without a shear flow, become mode-like.       
Quantifying uncertainty in decadal ocean heat uptake due to intrinsic ocean variability
Authors: Sinha Bablu , Megann Alex , Penduff Thierry , Molines Jean-Marc , Drijfhout Sybren
Published: March 2020

Remarkably, global surface warming since 1850 has not proceeded monotonically, but has consisted of a series of decadal timescale slowdowns (hiatus periods) followed by surges. Knowledge of a mechanism to explain these fluctuations would greatly aid development and testing of near term climate forecasts. Here we evaluate the influence of ocean intrinsic variability on global ocean heat uptake and hence the rate of global surface warming, using a 50-member ensemble of eddy-permitting ocean general circulation model simulations (OCCIPUT ensemble) forced with identical surface atmospheric condition for the period 1960-2015. Air-sea heat flux, integrated zonally and accumulated with latitude provides a useful measure of ocean heat uptake. We plot the ensemble mean difference of this quantity between 2000-2009 (hiatus) and 1990-1999 (surge). OCCIPUT suggests that the 2000s saw increased ocean heat uptake of ~0.32 W m-2compared to the 1990s and that the increased uptake was shared between the tropics and the high latitudes. OCCIPUT shows that intrinsic ocean variability modifies the mean ocean heat uptake change by up to 0.05 W m-2or ±15%. Moreover composite analysis of the ensemble members with the most extreme individual decadal heat uptake changes pinpoints the southern and northern high latitudes as the regions where intrinsic variability plays a large role: tropical heat uptake change is largely fixed by the surface forcing. The western boundary currents and the Antarctic Circumpolar Current (i.e. eddy rich regions) are responsible for the range of simulated ocean heat uptake, with the North Pacific exhibiting a particularly strong signal. The origin of this North Pacific signal is traced to decadal timescale latitudinal excursions of the Kuroshio western boundary current.
Induction Magnetometer transported by UAV for power lines monitoring
Authors: Korepanov Valery , Pronenko Vira , Dudkin Fedir , Prystai Andrii
Published: March 2020

Assessment of a power lines condition is an important task for all countries. It includes GPS mapping of the: 1) wire breaks; 2) places of the increased current leakage, for example corona detection; 3) degree of wires sagging between power line towers; 4) location and conditions of the power line towers; 5) vegetation encroachment along a power line corridor.  Considering that power line currents, including leakage currents, create strong magnetic field, use of magnetometers in the range from DC to sound frequencies for the solution of tasks 1-4 is highly prospective. At the same time, it is possible the control of the vegetation critical proximity to a power line adjacent zone by the increased leakage current (threats of the increased leakage current or breakdown to a tree crown). Thus the task 5 also can be solved.

The goal of the present report is to introduce the new design of miniature low-weight three-component sensor for measurement of alternative vector magnetic field onboard UAV – induction magnetometer (IM) - with autonomous system including two-component tiltmeter and GPS antenna inside in order to obtain precise measurement timing, UAV coordinates and altitude during movement. These data are stored in the SD memory card. Construction details, tests results and technical specifications of this IM for are presented.
CURAE – bridging the gap between regional CMEMS forecasts and coastal high-resolution applications
Authors: Mestres Marc , Pein Johannes , Espino Manuel , Schulz-Stellenfleth Johannes , Hansen Lars Boye , Staneva Joanna , Sánchez-Arcilla Agustín
Published: March 2020

The sustainable management of coastal areas with limited natural resources and subject to high anthropogenic pressures, based on complete forecast and analysis systems, is one of the main concerns of coastal authorities. Paradoxically, current oceanographic operational predictions are often insufficient to provide a good description of these regions due to low resolution/accuracy, the omission of relevant land-sea interactions, and the inadequate inclusion in the models of physical processes specific to the coastal fringe.

The CURAE project bridges this gap between the regional scales and the local coastal needs by establishing a 2-way connection between the existing CMEMS products and an innovative coastal information system (required by coastal water managers and littoral users alike) that considers hydro-morphodynamic interactions in an operational manner. The paper will present a new set of robust downscaling and coupling tools that have been developed to enhance the coastal dimension of present CMEMS products. The main advances refer to coastal processes not commonly incorporated in oceanographic predictions and that interact with the shelf sea, including the continental discharge in terms of water, sediment and nutrient fluxes.

The project is focused on two hydrodynamically contrasting sites with different uses (aquaculture and dredging) that demonstrate the added value and potential of CMEMS for coastal applications. The first case is the semi-enclosed microtidal Fangar Bay in the Ebro Delta (Spanish Mediterranean), in which bivalve farming coexists with tourism and nutrient- and sediment-laden freshwater discharges from rice fields in a hydrodynamically weak environment interacting with active domain geometries. The second study case is the macrotidal Wadden Sea/German Bight estuaries area, with concentrated plus distributed land discharge and significant dredging activities required for port operations. To ensure that the tools and conclusions derived from the project are as generic as possible, different numerical approaches (structured vs. unstructured grids) have been applied at each site and will be compared and discussed in the paper. The obtained results illustrate the benefits of quantitative forecasts for the healthy functioning of coastal systems, while proving the potential of CMEMS for supporting sustainable interventions in the coastal zone. The obtained advances are encouraging from scientific and application standpoints and underpin the need for a high-resolution coastal extension of CMEMS.
Upscaling laboratory measurements: Quantifying the role of hydrothermal alteration in creating geothermal and epithermal mineral resources
Authors: Heap Michael , Gravley Darren , Kennedy Ben , Gilg Albert , Bertolett Elisabeth , Barker Shaun
Published: March 2020

Hydrothermal fluids can alter the chemical and physical properties of the materials through which they pass and can therefore modify the efficiency of fluid circulation. The role of hydrothermal alteration in the development of geothermal and epithermal mineral resources, systems that require the efficient hydrothermal circulation provided by fracture networks, is investigated here from a petrophysical standpoint using samples collected from a well exposed and variably altered palaeo-hydrothermal system hosted in the Ohakuri ignimbrite deposit in the Taupō Volcanic Zone (New Zealand). Our new laboratory data show that, although quartz and adularia precipitation reduces matrix porosity and permeability, it increases the uniaxial compressive strength, Young’s modulus, and propensity for brittle behaviour. The fractures formed in highly altered rocks containing quartz and adularia are also more planar than those formed in their less altered counterparts. All of these factors combine to enhance the likelihood that a silicified rock-mass will host permeability-enhancing fractures. Indeed, the highly altered silicified rocks of the Ohakuri ignimbrite deposit are much more fractured than less altered outcrops. By contrast, smectite alteration at the margins of the hydrothermal system does not significantly increase strength or Young’s modulus, or significantly decrease permeability, and creates a relatively unfractured rock-mass. Using our new laboratory data, we provide permeability modelling that shows that the equivalent permeability of a silicified rock-mass will be higher than that of a less altered rock-mass or a rock-mass characterised by smectite alteration, the latter of which provides a low-permeability cap required for an economically viable hydrothermal resource. Our new data show, using a petrophysical approach, how hydrothermal alteration can produce rock-masses that are both suitable for geothermal energy exploitation (high-permeability reservoir and low-permeability cap) and more likely to host high-grade epithermal mineral veins, such as gold and silver (localised fluid flow).
Secondary Organic Aerosol Formation from Chinese Cooking Emission
Authors: Guo Song , Wang Hui , Zhu Wenfei , Zhang Zirui , Chen Zheng , Tang Rongzhi , Shen Ruizhe , Wang Tiantian , Yu Ying , Tan Rui , Hu Min
Published: March 2020

Organic aerosol (OA) constitutes a significant fraction of the atmospheric fine particulate matter that influences both air quality and climate. Secondary organic aerosol (SOA), which is formed through photo-oxidation of organic vapors in the atmosphere, is a major component of OA. There are some studies indicating the major role of Chinese cooking emissions in SOA formation in China. However, SOA formation is complex and uncertain.

In this study, we investigate the primary emission and secondary formation from Chinese cooking. The cooking ways include stir-fry, fry, and deep fry. The dishes were stir-fired shredded cabbage, fried Tofu, Kung Pao Chicken, and fired Chicken. Besides, different kinds of oils were fried to investigate the effect of oil on emission. The cooking emission was diluted and exposed a range concentration of oxidants (O3 and OH) in the Go-PAM. Two SMPS were used to measure particle number concentrations before and after oxidation. A DMA-CPMA-CPC system was used to obtain the size resolved particle density, and together with particle number concentration, primary and secondary particle mass concentrations were calculated. One ptr-MS was used to measure primary VOCs concentration, and one Aerodyne VOCUS was deployed to measure the VOCs after PAM. An AMS was used to measure the secondary particles. Our results showed that the SOA/POA ratios varied significantly from 5-35, depending on cooking ways. The emission stir-fired shredded cabbage has largest SOA/POA ratio of 35, followed by fried Tofu (22), Kung Pao Chicken (16), and fried chicken (5). The O:C ratio increased from 0.12~0.26 of cooking POA to 0.40~0.52 of cooking SOA. Our results suggest Chinese cooking contributes significantly to ambient not only primary particles but secondary particles.
Impact of spatial resolution and interpolation schemes of precipitation data on hydrological modeling
Authors: Hohmann Clara , Oh Sungmin , Kirchengast Gottfried , Foelsche Ulrich , Rieger Wolfgang
Published: March 2020

Hydrological modelling depends strongly on precipitation input. Especially, to simulate very localized heavy precipitation events, models require precipitation information with a high spatial and temporal resolution. In order to study the influence of precipitation station densities and interpolation schemes on hydrological model performance, we use gauge data from the highly dense station network WegnerNet (www.wegenernet.org). The WegenerNet is located in the southeastern Alpine forelands of Austria. It measures precipitation and other meteorological variables at a 5-min time sampling with about 150 climate stations in an area of about 22 km x 16 km (i.e ~ one station per 2 km²). We complement these data by the operational networks of the Austrian weather and hydrographic services (ZAMG and AHYD), leading to a total of 158 stations.

This highly dense station network permits us to analyze the precipitation data uncertainty for specific short and long duration events over the lower Styrian Raab catchment (about 500 km²) and its sub-catchments (about 10 to 50 km²). For modeling, we employ the process-based model WaSiM (www.wasim.ch) with a 100 m x 100 m spatial and a 30 minutes temporal resolution. We calibrated the model with all 158 precipitation stations and inverse distance weighting (IDW) interpolation scheme; this simulation is used as our reference run (Ref-158). We performed further simulations with only stations from ZAMG, the 5-Stations case, also include the stations from AHYD (adding another 3 stations), the 8-Stations case, and step by step including stations from the WegenerNet, the 16-Stations, 32-Stations and 64-Stations cases. For each simulation, we compared three interpolation schemes: two IDW setups and Thiessen polygons. Our study focuses on short duration, local extremes (convective events in 2009, 2010, 2011), but for comparison also includes long duration frontal extreme events.

Our results suggest that for the runoff simulation with dense precipitation stations (Ref-158) the effect of the interpolation scheme is negligible. By contrast, modeling with low-resolution precipitation data obtained from less than 10 stations, the interpolation scheme leads to deviations of over 20% in terms of peak flow. These deviations are especially pronounced for the short duration events. For the total Styrian Raab catchment, the 32-Stations case is as good as the Ref-158 case, independent of the interpolation scheme (mostly smaller than 10% deviation). For the long duration events and the IDW interpolation scheme even, the 5-Stations case is sufficient. For the smaller catchments, the peak flow is much more event-dependent. More stations do not necessarily lead to less deviation to the reference and no clear under- or over-estimation is visible.
The mechanism of 60-year and 15-year Arctic climate oscillations in climate model INM-CM5-0
Authors: Volodin Evgeny
Published: March 2020

Natural variability of Arctic climate is studied on the basis of preindustrial run with climate model INM-CM5-0.  The length of run is 1200 years. Temperature in Arctic shows significant peaks at periods of 60 and 15 years. Model climate oscillations are studied using technique of calculation of energy generation and impact to phase change.

60-year oscillation is generated mainly by advection of Atlantic water to Arctic ocean. Anomaly of oceanic currents associated with the oscillation are generated by gradients of density. Before warm phase there is negative anomaly of density near coasts and continental slope. This leads to enhancing of Atlantic water inflow to Arctic ocean, warming, increasing of density near slope and turning to negative phase of oscillation. Cyclonic vorticity over warm Bartents and Kara seas leads to wind currents that enhance inflow of Atlantic water to Arctic.

15-year oscillation is also generated by advection of Atlantic water to Arctic ocean, but anomalies of currents are generated mainly by wind stress. Before warm Arctic we have cold and fresh North Atlantic, that leads to positive NAO, it induces wind currents that transport more Atlantic water to Arctic ocean. This leads to Arctic warming, decrease of NAO and turn to opposite phase of oscillation. Warming of North Atlantic happens 3-4 years after maximum of Arctic warming. The response of Atlantic meridional streamfunction to the oscillation is studied.

"Ideal model" potential predictability experiments started from synthetic state preceding warm Arctic (cold and fresh North Atlantic) show that this oscillation can be predicted for time interval up to 10 years.
Image Regression Classification of Air Quality by Convolutional Neural Network
Authors: Kow Pu-Yun , Chang Li-Chiu , Chang Fi-John
Published: March 2020

As living standards have improved, people have been increasingly concerned about air pollution problems. Taiwan also faces the same problem, especially in the southern region. Thus, it is a crucial task to rapidly provide reliable information of air quality. This study intends to classify air quality images into, for example, “high pollution”, “moderate pollution”, or “low pollution” categories in areas of interest. In this work, we consider achieving a finer classification of air quality, i.e., more categories like 5-6 categories. To achieve our goal, we propose a hybrid model (CNN-FC) that integrates the convolutional neural network (CNN) and a fully-connected neural network for classifying the concentrations of PM2.5 and PM10 as well as the air quality index (AQI). Despite being implemented in many fields, the regression classification has, however, been rarely applied to air pollution problems. The image regression classification is useful to air pollution research, especially when some of the (more sophisticated) air quality detectors are malfunctioning. The hourly air quality datasets collected at Station Linyuan of Kaohsiung City in southern Taiwan form the case study for evaluating the applicability and reliability of the proposed CNN-FC approach. A total of 3549 datasets that contain the images (photos) and monitored data of PM2.5, PM10, and AQI are used to train and validate the constructed model. The proposed CNN-FC approach is employed to perform image regression classification by extracting important characteristics from images. The results demonstrate that the proposed CNN-FC model can provide a practical and reliable approach to creating an accurate image regression classification. The main breakthrough of this study is the image classification of several pollutants only using a single shallow CNN-FC model.

Keywords: PM2.5 forecast; image classification; Deep learning; Convolutional neural network; Fully-connected neural network; Taiwan

 
Holocene 6000-yr climate cycles in temperate and sub-tropical SST records – a cosmic ray connection?
Authors: Asten Michael
Published: March 2020

Temperature cycles with periods > 2000 yr, including peaks of order 6000 yr, has been reported in 14C proxy records in sediments for Fennoscandia (Olsen et al, 2005) and in glacier geochemistry for the Greenland ice-sheet (Mayewski et al, 1997, 2004).  Similar spectral peaks are also seen in 14C and 10Be isotopes in Greenland GRIP ice-cores (Xapsos, 2009); these cycles have been attributed to solar sunspot activity (Solanki et al, 2004). Complicating the question of existence of global millennial cycles, a comparison of d18O data in ice cores for Greenland (NGRIP) and Antarctica (EDML) has shown that for events prior to the Last Glacial Maximum (LGM), variations on the scale of 2-6kyr are markedly stronger in northern hemisphere records, associated with ice dynamics and Dansgaard–Oeschger (D-O) and Heinrich events (EPICA, 2006).

This paper discusses ocean sediment cores from three temperate zone and sub-tropical sites which provide sea-surface temperature (SST) histories using the UK37 proxy.  The available time spans are 20, 70 and 136 ka.  This study restricts the three records to 0-20ka thus avoiding complexities of D-O and Heinrich events, and of the associated phase changes between hemispheres which have been discussed by EPICA (2006).  We apply Lomb-Scargle spectral analysis and find that all three sediment SST records (Okinawa Trough, Murray Canyon south of South Australia, and Iberian Margin) show a high-confidence 6000 yr period spectral peak for the time span 0-20ka; we may conclude that this post-LGM peak is unlikely to be related to glacial-epoch ice dynamics.  The same 6000 yr spectral peak also shows in 0-20ka EDML d18O data from EPICA (2006).

The three SST records also show spectral peaks in the range 1000 to 3500 yr periods. The high-resolution Okinawa Trough shows a clear 2300 yr (Hallstatt) peak and the Iberian Margin similarly.  The peak is visible on southern hemisphere Murray Canyon data but is of doubtful significance.  A unique feature of the Iberian Margin data is a strong 3400 yr spectral peak.  This peak is also visible but much weaker on the other SST records, and on the 0-20ka EPICA d18O data.   We hypothesize the strong peak for the Iberian Margin is a consequence of effects of ocean and ice dynamics in the north Atlantic.

Similar spectral analysis of limited 10Be data from McCracken et al 2013, (available length limited to 0-10ka) supports the hypothesis that millennial cycles in temperature (especially the 6000 yr and 2300 yr periods) are global and associated with cosmic ray/solar magnetic activity.  This is in contrast with the longer Milankovich cycles which are well established as being primarily related to forcing associated with variable solar insolation.
Interaction between the Boreal Spring and Summer Tropical Atlantic Interannual Variability Modes
Authors: Martín-Rey Marta , Pelegrí Jose Luis , Sánchez-Gómez Emilia , Cassou Christophe
Published: March 2020

Traditionally, the interannual Tropical Atlantic variability (TAV) is thought to be governed by two air-sea coupled modes denoted as Meridional Mode (MM) and Equatorial Mode (EM), peaking in boreal spring and summer respectively. Several studies have proposed a possible connection between the MM and EM, but without reaching a consensus about its frequency, type and associated mechanisms. Remarkably, recent findings brought to light decadal changes in the structure, intensity and teleconnections of the EM along the observational record. In particular, new overlooked equatorial modes called ‘non-canonical EM’ and ‘Horse-Shoe mode’ have been reported, which exhibit significant sea surface temperature anomalies in the north tropical Atlantic region. This gives robustness to the connection between the boreal spring and summer interannual modes.

Here, using observational and CMIP6 model datasets, we demonstrate the existence of distinct interannual modes in the tropical Atlantic basin along the record. Furthermore, the emergence of these modes is not stationary on time and varies from some decades to the others.  In this study, using observations and coupled climate models we explore the connection between the MM and EM to generate the diverse of tropical Atlantic variability reported in previous works. Moreover, the air-sea mechanisms and ocean dynamics involved in the evolution of these modes and the role of the mean state in the connection between them is assessed.
Northern Hemisphere temperature to precipitation relationships during the last Glacial from pollen records and climate simulations
Authors: Sommani Anna , Weitzel Nils , Rehfeld Kira
Published: March 2020

The hydrological response to radiative forcing is less understood than the thermal one: many climate models have difficulties in simulating seasonal rainfall and its variability. Indeed, future precipitation projections are much more uncertain than those of temperature. However, confident projections of precipitation are of crucial importance, particularly for highly populated regions where agriculture strongly relies on seasonal rainfall, such as South and Central Asia.

Instrumental data from Eurasia show a negative correlation between temperature and precipitation on short timescales (10-3 to 100 years). However, on longer timescales (101 to 103 years), proxy data covering the Holocene show a positive correlation between temperature and precipitation. Climate models in contrast simulate a negative correlation on all timescales. To extend previous estimates to longer time scales, we focus on the last Glacial period, characterized by colder temperature than the Holocene as well as pronounced millennial-scale climate fluctuations in the Northern Hemisphere.

We reconstruct temperature and precipitation from four high resolution pollen records at mid-latitudes in the Northern Hemisphere. The estimates are compared with climate simulations. The chosen proxy sites cover the East and West coasts of both the Eurasian and North American continent. We employ four different statistical reconstruction methods to assess validity and biases of each method. The differences between reconstructed and simulated temperature-precipitation relationships as well as the zonal structure of orbital- and millennial-scale variations are examined. In particular, we explore the thermodynamic and dynamic contributions to the inferred relationships between temperature and precipitation.
Impact of Feedstock on Biochar Surface Properties: Practical Application of Boehm’s and Potentiometric Titration
Authors: Tomczyk Agnieszka , Szewczuk-Karpisz Katarzyna , Sokołowska Zofia , Kercheva Milena , Dimitrov Emil
Published: March 2020

Biochar is a material created through the pyrolysis of different kind of biomass. On the basis of last research reports, it was found, that the kind of used biomass influences on surface properties of biochar. These properties are of key importance in effectiveness of biochar as a soil sorbent.

The experiments were carried out using three biochars derived from: tobacco, sweet corn cobs and vineyard which are produced by the "double-barrel" method.

The aim of the research was an investigation the effects of feedstock kind on surface properties of biochar. The characteristics of selected surface properties of biochar included the determination of: functional group content by Boehm's acid-base titration method; determination of the variable surface charge and distribution of surface functional groups from potentiometric titration.

Biochar samples exhibit a high variable surface charge (Q) and content of surface functional groups. Tobacco has the highest Q and content of acidic groups, while sweet corn cobs - the lowest one. Variable surface charge provides information about the quantity of surface functional groups. The distribution of surface functional groups exhibits the existence of 3 peaks, which indicate the presence of acidic groups (carboxylic, lactonic and phenolic).

The biochar from tobacco, vineyard or sweet corn cobs possessed merit for the improvement pollution removal from soil.

Research was conducted under the project "Water in soil - satellite monitoring and improving the retention using biochar" no. BIOSTRATEG3/345940/7/NCBR/2017 which was financed by Polish National Centre for Research and Development in the framework of "Environment, agriculture and forestry" - BIOSTRATEG strategic R&D programme