bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing temperatures and fruit phenology – Comparing spatio-temporal trends for apple and pear in Belgium
Authors: Drepper Bianca , Gobin Anne , Verjans Wim , Van Orshoven Jos
Published: March 2020

For several cultivars of Malus domestica (apple) and Pyrus communis (pear), records of seven decades (1950-2019) from the Research Centre for Fruit in north-east Belgium revealed that flowering occurred on average 9.5 (apple) and 11.5 (pear) days earlier following dormancy periods (October to April) that were warmer than the average (Drepper et al., 2020). However, the relationship between winter temperature and flowering date is not linear and relative delays of flowering following the warmest winters suggest that increasing temperatures before and after dormancy break (so-called chilling and forcing periods) have respectively delaying or advancing effects on the time of flowering of fruit trees in temperate regions (Drepper et al., 2020).

Well calibrated phenological models are potentially usable to support decision-making regarding (new) orchard locations, cultivar selection and frost mitigation measures. To this end a dynamic chill model was coupled to a growing degree day forcing model, calibrated and validated to the local cultivars for the Research Centre’s conditions. The combined model was applied for apple and pear on a 5km X 5km grid covering the region of Flanders in Belgium and run based on observed temperatures since 1950 from the Belgian Meteorological Institute on the one hand and regionally downscaled and adjusted temperature projections from the CORDEX project for the near future (up to 2060) on the other hand. This temporal horizon is farm practice driven and covers the lifespan of orchards planted in 2020.

The results (forthcoming) allow to investigate spatial patterns of (i) date of start of flowering, (ii) the occurrence of frost during sensitive stages around the flowering time, (iii) timing of dormancy break as well as (iv) its interaction with forcing completion.    

 

Drepper, Bianca, Anne Gobin, Serge Remy, and Jos Van Orshoven. “Comparing Apple and Pear Phenology and Model Performance: What Seven Decades of Observations Reveal.” Agronomy 10, no. 1 (January 4, 2020): 73. https://doi.org/10.3390/agronomy10010073.

 
Particulate Monitoring and Evaluation of the Low-cost Sensors Performance at the Middle East
Authors: Alshehri Yasser , Alghamdi Mansour , Khoder Mamdouh , Almehmadi Fahd , Bamuneef Amer , Moathen Rayan , Stenchikov Georgiy
Published: March 2020

Key Words:
Air Quality; Air Pollution Monitoring; Low-Cost Sensors; Reference Methods, Microsensors, Experimental Campaign
 
Abstract:

Air quality in the Middle East (ME) is strongly affected by desert dust besides anthropogenic pollutants. The health hazards associated with particulate matter (PM) are the most severe in this desert region. The enhancement of Air quality monitoring is needed to implement abatement strategies and stimulate environmental awareness among citizens. Several techniques are used to monitor PM concentration. The air quality monitoring stations (AQMS) equipped with certified instrumentation is the most reliable option. However, AQMSs are quite expensive and require regular maintenance. Another option is low-cost sensors (LCS) that seen as innovative tools for future smart cities. They are cost-effective and allow to increase the spatial coverage of air-quality measurements as the number of conventional AQMS is generally quite small, so the current density of the monitoring stations in the Middle East is low.

In this work, we evaluated the PM air-quality climatology in the major cities in Saudi Arabia (Jeddah, Riyadh, and Dammam) for four years between 2016 and continued until 2020. We used the measurement data that were conducted by the Saudi Authority for Industrial Cities and Technology Zones (MODON) using certified reference AQMS installed inside the suburban areas of the three major cities in Saudi Arabia. Also, we tested the performance of the five LCS systems for eight months, starting in May 2019 and continued until January 2020. For this purpose, we set AQMS with the PM reference instrumentation (based on beta-ray absorption) side-by-side with five different LCS systems (based on light scattering) in the industrial part of Jeddah city. We collected, filtered, validated PM data, and applied standard measurement and calibration procedures.

The AQMS measurements show that in Summer, the daily mean PM concentrations exceed the World Health Organization (WHO) limits for PM2.5 and PM10 almost every day in Jeddah, Riyadh, and Dammam. The WHO limits are also frequently violated in the winter months. The AQMS measurements reliably show dust storm spikes when PM pollution is extremely high while all the LCSs fail to capture these severe events. We found that LCS and AQMS PM measurements are poorly correlated in Summer, but show slightly better results in fair-weather Winter days when humidity and temperature are low. But they still cannot capture severe dust events.
Characteristics of natural radiation background at the Callio Lab (Finland) performed within the BSUIN project
Authors: Kisiel Jan , Polaczek-Grelik Kinga , Szkliniarz Katarzyna , Walencik-Łata Agata , Joutsenvaara Jari , Puputti Hannah , Holma Marko , Enquist Timo
Published: March 2020

The BSUIN (Baltic Sea Underground Innovation Network) aims to enhance the accessibility of the underground laboratories in the Baltic Sea region for innovation, business and science. One of the BSUIN project activities is characterization of natural background radiation (NBR) in underground facilities. In this talk results from NBR measurements performed in Callio Lab, Pyhäsalmi, Finland, at the depth of 4100 m w.e. will be presented. The in-situ gamma spectra were collected with the use of  HPGe semiconductor spectrometer, whereas the  concentration of radon were measured with RAD7 electronic detector. In addition, the water and rock samples were taken for laboratory analysis in Institute of Physics, University of Silesia, Poland. The concentration radioisotopes in water samples were performed by using a liquid scintillation α/β counter (LSC) and α-particle spectrometry, while the concentration of radioisotopes in rock samples were performed by using laboratory gamma ray spectrometry and also α-particle spectrometry.
Subsea Water Isotope Sensors: A novel tool for continuous and in-situ analysis
Authors: Grilli Roberto , Blouzon Camillle
Published: March 2020

The isotopic composition of seawater represents an important fingerprint of water masses, containing information about conditions during their formation and evolution. Following the spatial and temporal variability of either δD or δ18O of water in the ocean will provide a direct link to the freshwater cycle, allowing to discriminate between different water masses, such as the one coming from glacier and sea ice melting, freshwater rivers and precipitations.

Information from physical parameters (e.g. temperature and salinity) are not always enough for identifying the undergoing processes, and current knowledge of water isotopes or noble gases in the ocean remains very poor due to scarcity of measurements obtained from discrete sampling followed by laboratory analysis.

Here we present a novel in-situ Membrane Inlet Laser Spectroscopy (MILS) sensor which is currently under development. The sensor will provide simultaneous and continuous measurements of water isotopes (both δD and δ18O, expected precision of ~0.05‰) and will be adapted for deployment from vessels, through boreholes into the ice shelves, and to be integrated in autonomous underwater vehicles (AUVs). The instrument will run on batteries, with an autonomy of ~12h.

From 2021, the MILS sensor will be ready for field deployments, particular in the Southern Ocean, where high resolution water isotope data inside ice shelf cavities could be coupled with modelling approaches for better understanding the processes at work in ocean - ice shelf interactions, and better constraint the ice melting processes in Antarctica, which remains today a major challenge.
Towards an artificial carbohydrates supply on Earth
Authors: Dinger Florian , Platt Ulrich
Published: March 2020

How to feed a growing global population in a secure and sustainable way? The conventional, biogenic agriculture has yet failed to provide a reliable concept which circumvents its severe environmental externalities — such as the massive use of land area, water for irrigation, fertiliser, pesticides, herbicides, and fossil fuel. In contrast, the artificial synthesis of carbohydrates from atmospheric carbon dioxide, water, and renewable energy would allow not only for a highly reliable production without those externalities, but would also allow to increase the agricultural capacities of our planet by several orders of magnitude. All required technology is either commercially available or at least developed on a lab-scale. No directed research has, however, yet been conducted towards an industry-scale carbohydrate synthesis because the biogenic carbohydrate production was economically more competitive. Taking the environmental and socioeconomic externalities of the conventional sugar production into account, this economical narrative has to be questioned. We estimate the production costs of artificial sugar at ~1 €/kg. While the today’s spot market price for conventional sugar is about ~0.3 €/kg, we estimate its total costs (including external costs) at >0.9 €/kg in humid regions and >2 €/kg in semi-arid regions. Accordingly, artificial sugar appears already today to be the less expensive way of production. The artificial sugar production allows in principle also for a subsequent synthesis of other carbohydrates such as starch as well as of fats. These synthetic products could be used as a feedstock to microorganisms, fungi, insects, or livestock in order to enhance also the sustainability of the biogenic production of, e.g., proteins.
On the origin of apparently negative minimum susceptibilities of hematite single crystals calculated from low-field anisotropy of magnetic susceptibility
Authors: Jezek Josef , Chadima Martin , Hrouda Frantisek
Published: March 2020

As shown in the literature several times, the calculation of the anisotropy of magnetic susceptibility (AMS) of hematite single crystals using standard linear AMS theory reveals that the calculated minimum principal susceptibility is parallel to the crystallographic c-axis, but is negative, which is however not due to diamagnetism as evidenced by direct measurements of susceptibility along the principal directions.

Susceptibility of a few hematite single crystals from Minas Gerais, Brazil, was measured in 320 directions using a special 3D rotator and the measurements were processed through AMS calculation by means of standard linear theory and through constructing contour diagram in equal-area projection. In addition, the deviations of the measured directional susceptibilities from the directional susceptibilities calculated from the fitted AMS tensor were calculated. The crystals show extremely high anisotropy, the susceptibility measured along the basal plane is several hundred to several thousand times higher than that along the c-axis and the AMS ellipsoids are very oblate, nearly rotational. The contour diagrams show relatively simple patterns of directional susceptibilities, similar to those of the second-rank tensor. However, the calculated AMS ellipsoids are slightly more eccentric than is the surface connecting the directional susceptibility values. The present study is assessing whether, realizing that the susceptibility along the c-axis is about three orders lower than that along the basal plane and taking into account the directional distribution of the fitting errors, one can ascribe the existence of the negative minimum susceptibilities calculated through standard linear theory to imperfect techniques of second-rank tensor fitting rather than to complicated magnetization mechanisms.  
Galactic cosmic ray induced ionisation on Venus and its effect on cloud droplet stability
Authors: Airey Martin , Harrison Giles , Aplin Karen , Pfrang Christian
Published: March 2020

Galactic cosmic rays are ubiquitous in solar system atmospheres. On Venus, the altitude of peak ion production due to cosmic rays (the Pfotzer-Regener maximum) occurs at ~63 km, within the optically thick region of the upper clouds. This indicates the possibility of electrical effects on droplets within Venusian clouds. Motivated by this, our VENI (Venusian Electricity, Nephology, and Ionisation) project explores effects of galactic cosmic ray (GCR) induced ionisation on cloud droplets in circumstances with relevance to Venus’ atmosphere. Charge is known to lower the critical supersaturation required for cloud droplets to form; slightly larger droplets are stable at lower saturation ratios if sufficiently charged. Condensation of gas directly onto ions is also potentially possible on Venus if the atmosphere is sufficiently supersaturated. GCRs and the secondary charged particles they produce are therefore anticipated to affect cloud droplet behaviour on Venus.

Experiments have been conducted using electrically isolated droplets, through levitation in a standing acoustic wave. The droplets are monitored with a high-magnification CCD camera to determine their evaporation rate and charge. The charge is measured both by the deflection in an electric field and by passing the droplet through a custom-built induction ring. A relationship between the evaporation rate and charge of the droplets is found to be consistent with theory, allowing droplet lifetime to be predicted for a given charge. Further experiments using sulphuric acid droplets in a carbon dioxide environment offer more direct relevance to the Venusian environment and cosmic ray enhancement due to solar energetic particles (SEPs) in space weather events will be simulated using a corona source.
Convection in future winter storms over northern Europe
Authors: Berthou Segolene , Kendon Elizabeth , Roberts Malcolm , Vanniere Benoit
Published: March 2020

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Gravity wave excitation during the coastal transition of an extreme katabatic flow in Antarctica
Authors: Vignon Étienne , Picard Ghislain , Durán-Alarcón Claudio , Alexander Simon P. , Gallée Hubert , Berne Alexis
Published: March 2020

The offshore extent of Antarctic katabatic winds exert a strong control on sea ice production and the formation of polynyas. In this study, we combine ground-based remotely-sensed and meteorological measurements at Dumont d’Urville (DDU) station, satellite images and simulations with the WRF model to analyze a major katabatic wind event in Adélie Land. Once developed over the slope of the ice sheet, the katabatic flow experiences an abrupt transition near the coastal edge. The transition consists in a sharp increase in the boundary layer depth, a sudden decrease in wind speed and a decrease in Froude number from 3.5 to 0.3. This so-called ‘katabatic jump’ visually manifests as a turbulent ‘wall’ of blowing snow in which updrafts exceed 5 m s −1 . The wall reaches heights of 1000 m and its horizontal extent along the coast is more than 400 km. By destabilizing the boundary-layer downstream, the jump favors the trapping of a gravity wave train  with an horizontal wavelength of 10.5 km. The trapped gravity waves exert a drag that significantly slows down the low-level outflow. Moreover, atmospheric rotors form below the first wave crests. The wind speed record measured at DDU in 2017 (58.5 m s −1 ) is due to the vertical advection of momentum by a rotor. A statistical analysis of observations at DDU reveals that katabatic jumps and low-level trapped gravity waves occur frequently over coastal Adélie Land. It emphasizes the important role of such phenomena in the coastal Antarctic dynamics.
Waves and sea-level rise induced flooding in the Maldives
Authors: Amores Angel , Marcos Marta , Pedreros Rodrigo , Le Cozannet Gonéri , Lecacheux Sophie , Rohmer Jérémy , Hinkel Jochen , Gussmann Geronimo , van der Pol Thomas , Shareef Ali
Published: March 2020

The Maldives, located in the Indian Ocean, are the paradigm of low-lying coral-reef islands where adaptation to climate change is essential. Besides the mean sea level rise in this region, that is expected to be around 1 m by the end of the century according to the last IPCC report, these islands are exposed to one of the largest swells in terms of significant wave height and peak period. In this study we characterize, using the output of global wind-wave models forced by wind fields from the CMIP5 ensemble delivered by CSIRO, the present conditions and future projections of the waves around the Maldivian archipelago, as well as the return periods for the predominant swell directions. We then propagate extreme waves inside the domain using WaveWatch III model run onto a high-resolution grid (down to 500 m at the coast). Finally, we evaluate the coastal impacts of extreme swell waves in two strategic case study islands with different exposures and where land reclamation and different adaptation solutions have been/are being done. To do so, we propagate waves using SWASH model with rising mean sea level towards the shoreline and assess the flooding extend under different conditions. This kind of studies are essential to help the policy makers in defining the most accurate and appropriate adaptation strategies.
Remote Sensing of Particulate Matter Air Quality using Geostationary and low earth orbiting satellite data
Authors: Christopher Sundar , Xue Zhixin , Gupta Pawan
Published: March 2020

Satellite imagery over the last several decades have provided spectacular views of dust storms, biomass burning smoke, and pollution aerosols near and far downwind of source regions. However, the effect on tropospheric aerosols near the surface is perhaps the most pressing issue, especially PM2.5 which is particulate matter with aerodynamic diameters less than 2.5 µm. In fact, the Global Burden of Disease (GBD) project of the Institute for Health Metrics and Evaluation (IHME) ranks ambient PM2.5 as the 6th-highest risk factor for early death. Also, the World Health Organization assessments indicate that more than 2 million deaths occur each year due to outdoor and indoor air pollution and more than half of this population lives in developing nations. Traditionally, PM2.5 is measured from ground-based instruments such as the Tapered Element Oscillating Microbalance (TEOM). Even though some nations have a good network of ground monitors they still cannot provide adequate coverage especially in regions that are not well populated. In most countries, monitoring is probably not a priority and measurements could vary from non-existent to very few monitors although recently there is a proliferation of low-cost sensors. However, it is indeed promising that the number of ground monitors have increased over the last decade and there are nearly 4000 monitors across the globe for which data are publicly available. The research community has long recognized that ground monitors alone are inadequate for providing a global picture of PM2.5 especially since a vast of population centers have no ground-monitoring networks. Therefore, other data sets are used to fill the gaps and complement the ground monitors. Satellite data by far offers the best solution for monitoring global air quality at spatial and temporal scales that are not possible by other means. Converting the column AOD to surface PM2.5 has been a subject of numerous studies and methods range from simple liner regression to complex statistical methods and machine learning approaches. We will use low earth orbiting and geostationary data sets coupled with meteorological data sets and ancillary information to demonstrate the progress and potential of satellite data for estimating PM2.5.

 
The implementation of Community Microwave Emission Model (CMEM) as the observation operator in TerrsysMP-PDAF
Authors: Lv Shaoning , Poll Stefan , Schalge Bernd , Garfias Pablo , Simmer Clemens
Published: March 2020

Studies with satellite-based passive microwave L-band observations have been fostered strongly by the launch of NASA's Soil Moisture Active Passive (SMAP) satellite on January 31, 2015 (Entekhabi et al. 2010), which complements and extends the observations at L-band by the ESA's Soil Moisture Ocean Salinity (SMOS) mission in orbit since 2009 (Kerr et al. 2001, Mecklenburg et al. 2012, Lievens et al. 2014). SMOS and SMAP data assimilation studies started during their pre- and post-launch period. Flores et al. (2012) used an Ensemble Kalman Filter to constrain the uncertainties of the simulated soil moisture fields from physical-based hydrological models. Our work intends to explore the use and value of passive L-band satellite observations for ensemble-based data assimilation with fully-coupled terrestrial system models for mesoscale catchments. An observation operator for satellite-based passive microwave (PMW) observations based on the community microwave emission model (CMEM) (de Rosnay et al. 2009, Drusch et al. 2009) has been modified, applied and tested in an ideal case developed within the FOR2131 (Schalge et al. 2016) with the coupled subsurface-land surface-atmosphere simulation platform TerrSysMP (Shrestha et al. 2014), which couples ParFlow (subsurface), Community Land Model (CLM, surface), and COSMO (atmosphere). We achieve the development of a satellite simulator for passive L-band observations of the satellite missions SMAP and SMOS and its adaptation to the ideal case, and the lower-resolution TerrSysMP model applied for data assimilation (TerrSysMP-PDAF).
Elevation-dependent warming in the tropical and subtropical Andes
Authors: Bonfim Osmar , Mortarini Luca , Toro Ivan , Palazzi Elisa
Published: March 2020
Components of Impact Plasma: Velocity and Temperature
Authors: Kočiščák Samuel , Fredriksen Åshild , DeLuca Michael , Pavlů Jiří , Sternovsky Zoltan
Published: March 2020

Impact ionization is a process of plasma generation upon hypervelocity impact of a small body (e.g., interplanetary dust grain) onto a solid surface.  Such process may play an important role in astrochemistry. Understanding the plasma generation, we can clarify the interpretation of proclaimed dust impact detections onto antenna-equipped space experiments, which have become widely popular in the recent years.

We present the data gained in charge generation and collection experiments conducted at the University of Colorado IMPACT hypervelocity dust accelerator facility. The impacts are of sub-micrometer cosmic dust simulants onto a metal target in the range of velocities between 1 and 50 km/s. We discuss measured charge collection on a microsecond scale as well as aggregated results of electron and ion drift velocities and temperatures and specifically their dependence on the velocity of the impactor.
Developing an Autonomous Hovercraft for Benthic Surveying in Very Shallow Waters
Authors: Troup Meghan , Barclay David , Hatcher Matthew
Published: March 2020

Benthic surveys in very shallow water (< 1 meter) are often carried out by remote sensing methods such as LiDAR, satellite imagery, and aerial photography, or by written observations paired with GPS point measurements and underwater video. Remote sensing can be helpful for large scale mapping endeavors, but the optical methods commonly used are limited in their effectiveness by cloud cover and water clarity. In situ surveys are often carried out manually and can therefore be quite inefficient. A proposed alternative method of small scale, high resolution mapping is an autonomous, amphibious hovercraft, fitted with high frequency single-beam and side-scan sonar instruments. A hovercraft can move seamlessly from land to water which allows for convenient and simple deployment. The sonar instruments are attached to a boat-shaped outrigger hull that can be raised and lowered automatically, enabling data collection in water as shallow as 10 cm. These data are used to extract seafloor characteristics in order to create detailed maps of the research area that include information such as sediment type, presence and extent of flora and fauna, and small-scale bathymetry.
Simulation–optimization model for optimum water allocation between environmental and agricultural demand using a coupled WEAP-MODFLOW model: Application in Miyandoab plain, Urmia basin, Iran
Authors: Dehghanipour Amirhossein , Schoups Gerrit , Zahabiyoun Bagher
Published: March 2020

In this study, we developed a simulation-optimization model for optimum water allocation to meet environmental flow requirements and agricultural demand. The simulation model consists of three modules: a hydrologic module, an agronomic module, and an economic module. The hydrologic module is based on a dynamic coupling of WEAP and MODFLOW, and includes water balances for the crop root zone, the surface water system, and the underlying aquifer. The agronomic module simulates the effect of deficit irrigation on crop yield response in each growth stage, while the economic module calculates the net benefit of crop production. The optimization model contains two objective functions, one related to agricultural production and the other related to environmental flows. These conflicting objective functions are maximized using the Multi-Objective Particle Swarm Optimization algorithm. Decision variables include crop acreages, minimum environmental flow requirements in the river, and the degree of deficit irrigation. We applied the simulation-optimization model to the irrigated Miyandoab plain in the semi-arid northwest of Iran, for the historical period 1984 to 2013. There is competition between irrigation demands in the plain and environmental flow requirements to downstream Lake Urmia, which has been shrinking in recent years due to decreased inflows. Our results quantify what the (Pareto) trade-off looks like between meeting environmental and agricultural water demand in the region. We find that historical water allocations were suboptimal and that both agricultural and environmental benefits can be increased by better management of cropping decisions, deficit irrigation, and environmental flow requirements. We further show that increased groundwater use for irrigation can partly alleviate the trade-off, but that it leads to significant declines in groundwater levels due to the relatively small specific yield of the aquifer.
Wave Propagation and Global Implications of Magnetopause Surface Eigenmodes
Authors: Archer Martin , Hartinger Michael , Plaschke Ferdinand , Rastaetter Lutz
Published: March 2020

Using global magnetohydrodynamic simulations we investigate the recently discovered eigenmode of the magnetopause surface – the natural response of the boundary to impulsive solar wind transients. We show that following the directly driven motion of the magnetopause by a pressure pulse, decaying oscillations of the boundary follow in agreement with theoretical predications and previous simulations of the magnetopause surface eigenmode. Across the equatorial magnetosphere these oscillations originate at the subsolar point and maintain a near-constant frequency through all local times, though into the flanks a secondary higher-frequency signal emerges consistent with the expectations of Kelvin-Helmholtz generated surface waves. Focusing only on the eigenmode shows its amplitude grows with local time away from the subsolar point, with the waves showing no azimuthal propagation in the region 9-15h MLT – surprising given the convecting effect downtail of the magnetosheath flow.  In the noon-midnight meridian the eigenmode is confined to the dayside magnetosphere. Comparing these results to MHD theory, we propose how the structure of the magnetopause surface eigenmode is determined by the properties of the magnetospheric system and how it may influence global dynamics during impulsive events.
Evidence of shallow lithosphere and crust in the western continental margin of India through modeling of gravity data
Authors: Chouhan Avinash Kumar , Choudhury Pallabee , Pal Sanjit Kumar
Published: March 2020

The seismically active western continental margin of India (WCMI) comprises of the three pericratonic rifts (Kachchh, Cambay, and Narmada) and the Saurashtra uplift that has been formed during the northward trek of the Indian plate. In the present study, forward and inverse modeling of the Bouguer anomaly have been done to calculate the topographical variation of the Moho and Lithosphere-Asthenosphere boundary (LAB). Inversion is implemented over the band-pass (cut-off wavelength 100 and 200 km) and low-pass (cut-off wavelength 200 km) filtered Bouguer anomaly with the assumption of constant density contrast between the Moho and LAB interfaces. Results of the inversion reveal significant variation of the Moho and LAB depths over the WCMI that vary between (1) 33-42 km and 82-124 km in the Kachchh rift, (2) 34-42 km and 68-110 km in the Cambay rift and north Gujarat, (3) 36-44 km and 80-95 in the Narmada rift and south Gujarat and (4) 34-41 km and 85-135 km in the Saurashtra peninsula, respectively. Using the present results of the Moho and LAB depths as constraint, forward modeling has been performed over the band-pass filtered (cut-off wavelength of 100 and 500 km) Bouguer anomaly. The result of forward modeling reveals that the magmatic underplating layer is enveloping the entire crust of the WCMI which indicates that the whole region has been affected by the Reunion hotspot volcanic activity. A thin lithosphere beneath the Cambay and Kachchh rift has been observed which expedited the eruption of volcanic material through the pre-existing rift zones. The Cambay rift is the zone of high geothermal gradient where LAB is upwarped and both the signatures indicate the existence of partial melting condition at a shallow depth that is also confirmed by recent seismological studies. 
Tropical cyclones and climate change: Recent results and uncertainties
Authors: Camargo Suzana , Lee Chia-Ying , Sobel Adam , Tippett Michael
Published: March 2020

Here I will describe recent results on the influence of climate change on tropical cyclones (TC) using the Columbia Hazard (CHAZ) model. Using environmental conditions from reanalysis and climate models and a statistical-dynamical downscaling methodology (Lee et al. 2018), CHAZ generates synthetic TCs that can be used to analyze TC risk.  I will first discuss the current knowledge and uncertainties in TC frequency projections. Then I will present our recent projections on TC frequency using CHAZ. Focusing on the North Atlantic, I will finish by discussing how we can use a combination of observations, high-resolution models and CHAZ synthetic TCs in the historical period to inform the reliability of the models' TC frequency projections. 

Reference:

Lee, C.-Y., M.K. Tippett, A.H. Sobel, and S.J. Camargo, 2018. An environmentally forced tropical cyclone hazard model. J. Adv. Model. Earth Sys., 10, doi: 10.1002/2017MS001186.
Classification of glaciers during summer in Southern Rocky Mountain Trench using surface albedo and temperature anomalies
Authors: Naeimi Ali , Sharp Martin
Published: March 2020

Under most atmospheric conditions, the albedo and temperature of surface snow and ice are two of the main influences on the energy budget for glacier melting. Given that surface albedo and temperature are linked, knowing where and when negative albedo and positive surface temperature anomalies coincide is important for identifying locations and time periods in which anomalously high rates of surface melting are likely. We used measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA's AQUA and TERRA satellites to map the albedo and surface temperature of snow and ice  on glaciers in the of Southern Rocky Mountain Trench ecoregion in the summer months (June-August) from 2000 to 2018. We use these data to identify specific regions and time periods in which low albedo and high surface temperature coincide since these conditions are likely to support anomalously high rates of surface melting. We also use these data to identify regions/periods in which albedo is particularly low while surface temperature is average or low, since such conditions suggest localized and/or short-term decoupling between the two parameters. We found anomalously low albedo and average/low temperature consistently at multiple glaciers during time periods when there were major forest fire events. We suggest the low albedo results from deposition of pyrogenic carbon from forest fires. We found that, on average, ~25% of the glaciers in the region experienced increasingly negative albedo anomalies and increasingly positive temperature anomalies in summer months from 2000 to 2018. However, we also found that for ~45% of the glaciers that are small, there was a poor correlation between the timing of albedo and temperature anomalies. Our results indicate that the correlation between albedo and temperature was weaker for the small glaciers, and identify specific glaciers that are likely the most vulnerable to climate warming.
Modeling particle precipitation and effects on the ionospheric conductivity
Authors: Yu Yiqun , Tian Xingbin , Zhu Minghui , Pr Shreedevi
Published: March 2020

Particle precipitation originated from the magnetosphere provides important energy source to the upper atmosphere, leading to ionization and enhancement of conductivity, which in turn changes the electric potential in the MI system to influence the plasma convection in the magnetosphere. In this study, we simulate ring current particle precipitation caused by several important loss mechanisms, including electron precipitation due to whistler wave scattering, ion precipitation due to EMIC wave diffusion and field line curvature scattering. These physical mechanisms are implemented in the kinetic ring current model via diffusion equation with associated pitch angle diffusion coefficients. The precipitation is subsequently input to a two-stream transport model at the top of ionosphere in order to examine its impact on the ionsopheric conductivity. It is found that during intense storm time, electron precipitation of tens of keV dominates in the dawn sector and leads to significant enhancement of conductivity at low altitudes. On the other hand, proton precipitation on the nightside mostly occurs for energy below 10 keV, and contributes to ionization above 100 km, resulting in enhancement of conductivity there. Consequently, the height profile of both Pedersen and Hall conductivity exhibits two layers, potentially complicating the current closure in the ionosphere system.
Experimental Study on the Evolution of River Water Quality and Riverbank Percolation Water Quality under Reclaimed Water Replenishment
Authors: guo zhongfang , pan chengzhong
Published: March 2020

Due to the intensified influence of human activities, Yongding river presents a sharp decrease in water quantity and a trend of continuous deterioration of water environment, and the ecological environment is seriously damaged. Under this background, Yongding river ecological reconstruction project needs to be carried out urgently, and ecological water replenishment mode needs to be determined urgently. In order to explore the influence of multi-water source ecological replenishment mode on the evolution of river water quality and riverbank percolation water quality, this study conducted a simulation experiment to explore the influence of flow rate, temperature and soil percolation on reclaimed water replenishment water quality. The results show that the increase of flow velocity is beneficial to the degradation of pollutants. Compared with high temperature, the degradation capacity of pollutants at low temperature is significantly better than that at high temperature, indicating that low temperature is beneficial to the improvement of reclaimed water quality to some extent. Some water quality indexes of riverbank leachate improved to some extent, but the water passing through the soil was slightly eutrophication due to the aggregation and adsorption of river bottom sediments. The final results show that the velocity of flow has the greatest influence on the quality index of regenerated water.
Pruning intensity of street trees and associated effects on ecosystem services
Authors: Cheng Su-Ting , Wei Shuo
Published: March 2020

Urban street trees provide multiple ecosystem services to city residents. In the Taipei city of Taiwan, street tree pruning is periodically applied due to disastrous prevention of typhoons or storms. To understand how pruning intensity affects the value of ecosystem services, we evaluated the changes of ecosystem services provided by a total of 87,014 street trees in Taipei in terms of pollution removal, carbon storage, gross carbon sequestration, and runoff avoidance. The current status of each ecosystem service was calculated using i-Tree Eco developed by US Forest Service based on the street tree inventory conducted by Parks and Street Lights Office, Taipei City Government during 2015 to 2017. Inventory information included tree species, diameter at breast height (DBH), tree height, and their locations. To simulate pruning intensity from 10% to 100%, we adjusted the crown missing rate from the current canopy cover estimated by DBH and tree height and quantified their associated effects on the ecosystem services. Then, for comparison purposes, each ecosystem service was transformed into monetary values using US market value of water, carbon, air pollution removal, and electricity. Our analysis showed that the Taipei street trees currently hold a relatively stable age structure with lower risk of disease or pest outbreak. These trees were estimated to deliver ecosystem services of equivalent value of 5.6 million USD, to which 4.97 million USD was contributed by carbon storage. Based on the pruning intensity simulation, we suggest a 20% or lower pruning intensity considering street trees’ impairment and physiology, to maximize the ecosystem service values. We also recommend landscape managers to monitor and assess the growth and health of the street trees to promote sustainable development in the Taipei city.
Comprehensive insights into metabolic potentials and engineered applications of two novel simultaneous aerobic denitrification and phosphorus removal bacteria, Achromobacter sp. GAD3 and Agrobacterium sp. LAD9
Authors: Liu Shufeng , Chen Qian , Liu Sitong , Ni Jinren
Published: March 2020

Bacteria capable of simultaneous aerobic denitrification and phosphorus removal (SADPR) are promising for the establishment of novel one-stage wastewater treatment systems. Nevertheless, insights into the metabolic potentials and engineered applications of SADPR-related bacteria are limited. Firstly, comprehensive metabolic models of two efficient SADPR bacteria, Achromobacter sp. GAD3 and Agrobacterium sp. LAD9, were obtained by high-throughput genome sequencing. With succinate as the preferred carbon source, both strains employed a complete TCA cycle as the major carbon metabolism for potentials of various organic acids and complex carbon oxidation. Complete and truncated aerobic denitrification routes were confirmed in GAD3 and LAD9, respectively, facilitated by all the major components of the electron transfer chain via oxidative phosphorylation. Comparative genome analysis revealed distinctive ecological niches involved in denitrification among different phylogenetic clades within Achromobacter and Agrobacterium. Excellent phosphorus removal capacities were contributed by inorganic phosphate uptake, polyphosphate synthesis and phosphonate metabolism. Additionally, the physiology of GAD3/LAD9 is different from that displayed by most available polyphosphate accumulating organisms, and reveals both strains to be more versatile, carrying out potentials for diverse organics degradation and outstanding SADPR capacity within a single organism. Secondly, both GAD3 and LAD9 were successfully applied for bioaugmented treatment of municipal wastewater in a pilot-scale sequencing batch reactor. At an appropriate COD/N ratio of 8, the bioaugmentation system exhibited stable and excellent carbon and nutrients removal, the averaged effluent concentrations of COD, NH4+-N, TN and TP were 20.6, 0.69, 14.1 and 0.40 mg/L, respectively, which could meet the first class requirement of the National Municipal Wastewater Discharge Standards of China (COD < 50 mg/L, TN < 15 mg/L, TP < 0.5 mg/L). Clone library and real-time polymerase chain reaction analysis revealed that the introduced bacteria greatly improved the structure of original microbial community and facilitated their aerobic nutrients removal capacities. This proposed emerging technology was shown to be an alternative technology to establish new wastewater treatment systems and upgrade or retrofit conventional systems from secondary-level to tertiary-level.
Numerical investigation of frictional heating effect on the earthquake faulting based on the Ruina- and Chester-Higgs- models
Authors: Gao Yaqi , Shi Baoping
Published: March 2020

Rate- and state-dependent friction laws (RSF laws) are empirical laws derived from laboratory experiments related to rock friction. They have been used to quantitatively describe complex fault friction processes. With a combination of the RSF laws and the McKenzie-Brune frictional heat generation model, we have studied the effects of frictional heating processs on the fault strength variation and temporal evolution of temperature based on the spring-slider-fault system subjected to Ruina and Chester-Higgs RSF laws. The system equations are solved efficiently by Dormand-Prince method with adaptive steps. First, with a comparison to the Ruina- model in which the temperature effect due to frictional heating on frictional strength is neglected, the numerical results show that the fault will be unstable slightly earlier for the Chester-Higgs- model in which the temperature effect due to frictional heating on frictional strength is taken into consideration, which indicates that the rise of temperature caused by frictional heating can lead to a slight time advance of fault instability. Second, by contrast with Ruina- model, the frictional strength will keep a little bit higher for the Chester-Higgs- model when the fault sliding at high speed, indicating that frictional heat can strengthen faults to a certain extent. Third, the simulation results also suggest that, at the same rupture velocity, the temperature change for the Chester-Higgs- model is much smaller than that given by the Ruina- model, indicating that frictional heat can also restrain the sharp rise of temperature on fault surface. In addition, under the same parameters and initial conditions, the seismic occurrence time giving by the Chester-Higgs- model is obviously shorter than that by the Ruina- model, indicating that a significant effect of friction heating generated on entire fault temporal evolution could greatly reduce the seismic recurrence time. Correspondingly, both static stress drop and total slip resulted from the Chester-Higgs- model is also smaller than that from the Ruina- model, respectively.
Recent advances in GNSS-A observation technology and networks and latest observation results around Japan Islands
Authors: Yokota Yusuke , Ishikawa Tadashi , Watanabe Shun-ichi , Nakamura Yuto
Published: March 2020

Our research group has been studying advanced GNSS-A (Global Navigation Satellite System – Acoustic ranging combination) technique over two decades. In recent years, detection sensitivity of GNSS-A observations has been sophisticated by improving the accuracy and frequency of analysis technology and acoustic systems [e.g., Yokota et al., 2018, MGR; Ishikawa et al., in prep]. The current observation frequency is more than 4 times/year, the observation accuracy for each observation is less than 2 cm, and it can detect a steady deformation rate of 1 cm/year or less and an unsteady fluctuation of 5 cm or less. Also, efforts are being made to strengthen the observation network.

GNSS-A observations for the 2011 Tohoku-oki earthquake and its postseismic field revealed the details of the crustal deformation field on the Japan Trench side [Sato et al., 2011, Science; Watanabe et al., 2014, GRL]. The long-term observation data in the Nankai Trough region revealed the strain accumulation process at the interseismic period [Yokota et al., 2016, Nature; Watanabe et al., 2018, JGR; Nishimura et al., 2018, Geosphere]. Furthermore, detection and monitoring of large-scale slow slip events (SSEs) in the shallow part of the Nankai Trough was achieved by recent sensitivity improvements [Yokota & Ishikawa, 2020, Science Advances]. The detected postseismic fields, coupling condition and shallow SSEs contain universal features that should be shared in many subduction zones. Here, along with the latest observations, we discuss spatial and temporal relationships of these events, strain accumulations and releases along subduction zones around Japan by GNSS-A and its impact on slow earthquake science.

Recently, because of the need for continuous monitoring a shallow SSE, the monitoring ability of GNSS-A was also investigated. It was confirmed that relatively large-scale shallow SSE (surface deformation: > 5 cm) could be monitored. However, the ability to determine the time constant of an SSE is poor. For monitoring the detail of an SSE, it is essential to improve the observation frequency in the future. Here, we also discuss the technical issues to be considered and their solution plans (e.g., new platform and system).
High-Resolution Simulation of Hydraulic Structures in a Typhoon Induced Urban Flood Event
Authors: Cui Yunsong , Liang Qiuhua , Wang Gang , Zeng Jian , Hu Jinchun
Published: March 2020

Due to climate change and rapid urbanization, urban flooding has become one of the major natural hazards threatening the safety of people and their properties and affecting the overall sustainability of cities across the globe, especially developing countries such as China. Flood modelling has now provided an indispensable tool to support urban flood risk assessment and management, and inform the planning of cities that are more resilient to flooding.

Hydraulic structures, e.g. regulation gates and pumping stations, play an important role in urban flood risk management. However, direct simulation of these hydraulic structures is not a current practice in 2D urban flood modelling. This work presents and applies a robust numerical approach to directly simulate the effects of hydraulic structures in a 2D high-resolution urban flood model. An additional computational module is developed and fully coupled to a GPU-accelerated finite volume shock-capturing urban flood model to directly simulate the highly transient flood waves through hydraulic structures. The improved flood model is applied to  reproduce a flood event induced by Typhoon “Lekima” in 2019 in Yuhuan, Zhejiang Province, China. At 3m resolution, the model is able to simulate the complete process of the flood event in nearly 3.5 times faster than real time, demonstrating the efficiency and robustness of the new fully coupled model for high-resolution food modelling in cities. Further simulations are performed to systemically investigate the effect of hydraulic structures and different operational regulations on flood dynamics and associated risks, demonstrating the importance of directly considering hydraulic structures and their operations in 2D high-resolution urban flood modelling.