bluuebunny/crossref_metadata_2025 huggingface dataset:
Trade-offs, synergies and economic relationships among ecosystem services
Authors: Sone Jullian , Gesualdo Gabriela , Rosalem Lívia , Oliveira Paulo , Wendland Edson
Published: March 2020

All land uses provide ecosystem services (ES), which have been depleted due to the lack of soil conservation practices along with the intensive use of land for meeting the water-energy-food nexus demand. The economic incentive is a first step towards attracting farmers’ interest in protecting and conserving ES. Farmers, stakeholders, and decision-makers need to understand the value and importance of watershed services through a straightforward cost-effective analysis of conserving and/or protecting them. Economic feasibility affects the volunteer enrolment in payment for ecosystem services (PES) programmes for adopting soil conservation practices in rural areas; nonetheless, it is still poorly understood regarding investments in ES restoration and preservation. There is very little information on the restoration of water provisioning in rural basins that participated in PES programmes. Additionally, most studies focus on programmes for one specific type of landowner, putting aside the plurality of landowners in the basin. It undermines PES programmes implementation when assessing individual preferences and willingness to pay. Thus, we aim to compare costs and benefits from incentivising soil conservation practices and forest restoration in a rural basin through a cost-benefit analysis and quantitative improvements of water provision and soil erosion control; moreover, we will use hydrological and economic-decision models to asses the uncertainties from the relationship between soil conservation practices and watershed services under climate change. The Guariroba River Basin (36,200 ha), located on the rural side of Campo Grande city ‒ Brazil, currently provides 34% of the drinking water demand in the urban area — once provided about 50% — since converting native Cerrado vegetation of the basin for cattle farming has led to a decrease in water provisioning due to soil degradation and, consequently, reservoir siltation. In 2009, the city hall launched a PES Programme called ‘Manancial Vivo’ (MVP). In this context, it is fundamental to understand how uncertainties in the input data, economic models structure, and parameters estimation are consistently integrated into hydro-economic models. By this, we will assess different hydro-economic scenarios of water availability to understand uncertainties and hydrological trade-offs. We expect to respond to some questions: whether the Brazilian PES programme model is environmentally and economically adequate; how water-food-energy insecurity nexus affects PES policies; and what role PES plays in building resilience to water supply systems and helping people to adapt to climate change effects.
Neotectonic deformation in the Southwestern Tian Shan, Western China: evidence from paleomagnetic study of Quaternary sediments from the Mingyaole Anticline
Authors: Qiao Qingqing
Published: March 2020

This paleomagnetic study is located at the north-west extremity of the Tarim Basin and has aimed to constrain the style of Neotectonic deformation where indentation of the Pamir Orogen into the southward-verging Tian Shan frontal zone has produced a complex zone of thrusting, folding and strike-slip. Sampling focused on two Pliocene to Pleistocene sedimentary formations folded across the Mingyaole Anticline, the major structural feature between the two frontal zones, has yielded well-grouped characteristic remanent magnetizations at 18 of 24 sites and a positive fold test. Together with fabric evidence, the results indicate a probable post-depositional detrital origin for the remanence. The results show that only small inter-locational vertical-axis rotations have occurred within the Kashi-Atushi fold and thrust system since the Miocene and imply that the Kashi depression has behaved as a quasi-rigid block. A common 15-30º counterclockwise (CCW) rotation relative to Eurasia since the Miocene of the Kashi Depression and the bordering Tian Shan range proves to be unrelated to the right lateral motion along the Talas-Ferghana intracontinental transform fault to the north west. This contrast is provisionally interpreted as taking place along a transfer fault between different segments of the thrust belt. Ongoing CCW rotation of the Tarim Basin is interpreted as a regional response to impingement by northward movement of the larger Tibetan Block to the south east.
Single-Crystal Structure Refinement of Presolar Silicon Carbide
Authors: McKenzie Warren , Dera Przemyslaw
Published: March 2020

Presolar silicon carbide, identified by anomalous 12C/13C, have long been the only direct physical sampling of asymptotic giant branch stars and Type-II supernovae (SNII) ejecta. The bulk of non-novae grains form in the dust clouds of 1-3M☉ carbon stars in the thermally pulsing asymptotic giant branch (AGB) phase of their life. While these grains have been extensively studied for their unique isotopic signature characteristic of their exotic origin and trace gasses carrying the s-process and r-process nucleosynthetic signature, to date studies on their structures of presolar grains have been limited to electron diffraction surveys using transmission electron microscopy. We present high-resolution single-crystal structural refinement of presolar silicon carbides determined using data synchrotron x-ray diffraction data collected at Advanced Photon Source. Preservation and resolvability of the circumstellar pressure/temperature regime was determined with an examination of nanostrain states in several grains of presolar silicon carbide. By accounting for the environment present at (1) circumstellar formation, (2) interstellar transport, and (3) asteroidal and meteoritic storage and shock environments we hope to open a new opportunity to directly study the limits of our theoretical understanding of stellar structures.
Application of multi-sensor unmanned aerial system for identification of hydrothermal alteration zones
Authors: Choi Yosoon , Baek Jieun , Suh Jangwon , Kim Sung-Min
Published: March 2020

In this study, we proposed a method to utilize a multi-sensor Unmanned Aerial System (UAS) for exploration of hydrothermal alteration zones. This study selected an area (10m × 20m) composed mainly of the andesite and located on the coast, with wide outcrops and well-developed structural and mineralization elements. Multi-sensor (visible, multispectral, thermal, magnetic) data were acquired in the study area using UAS, and were studied using machine learning techniques. For utilizing the machine learning techniques, we applied the stratified random method to sample 1000 training data in the hydrothermal zone and 1000 training data in the non-hydrothermal zone identified through the field survey. The 2000 training data sets created for supervised learning were first classified into 1500 for training and 500 for testing. Then, 1500 for training were classified into 1200 for training and 300 for validation. The training and validation data for machine learning were generated in five sets to enable cross-validation. Five types of machine learning techniques were applied to the training data sets: k-Nearest Neighbors (k-NN), Decision Tree (DT), Random Forest (RF), Support Vector Machine (SVM), and Deep Neural Network (DNN). As a result of integrated analysis of multi-sensor data using five types of machine learning techniques, RF and SVM techniques showed high classification accuracy of about 90%. Moreover, performing integrated analysis using multi-sensor data showed relatively higher classification accuracy in all five machine learning techniques than analyzing magnetic sensing data or single optical sensing data only.
Application of an Integrated Assessment Model (IAM) to for strategic scale delta assessment of socio-ecological risk: Supporting Policy in Coastal Bangladesh
Authors: Hutton Craig , Nicholls Robert , Chapman Alex , Marcinko Charlotte , Rahman Munsur , Haque Anisul , Harfoot Andrew , Hazra Sugata , Salehin Maskfiq
Published: March 2020

There is growing recognition that new approaches, underpinned by more system-oriented decision support tools, will be required to facilitate development compatible with the Sustainable Development Goals (SDGs) and to prevent the risk of dangerous socio-environmental breakdown. We demonstrate the potential of Integrated Assessment Models (IAMs) to inform strategic policy decision making at a regional level, helping to understand key trade-offs as well as indirect or unintended impacts. The stakeholder co-produced Delta Dynamic Emulator Model (ΔDIEM) model is applied to the southwest coastal zone (pop. 14m) where high rates of extreme poverty prevail. The model integrates biophysical drivers, ecosystem services and community level household wellbeing, and in this work is applied an behalf of the Planning Commission of the Government of Bangladesh in order to assess strategic risk in coastal Bangladesh (2050) and particularly to support the Bangladesh Delta Plan 2100. The intervention we investigated included i) A proposed extensive polder network in the south-central region of coastal Bangladesh ii) Strategic development of a chronically waterlogged area of the delta. In both areas we highlight insights on implications of biophysical drivers on poverty, livelihoods and inequality as well as on risk transfer between regions and populations associated with implementation. In doing so we critically assess IAMs’ growing potential to ask and explore key questions and scenarios about the functioning of integrated biophysical and socioeconomic systems. Finally, we point to ongoing applications of the model in West Bengal
COSMIC-2 Status and GNSS Radio Occultation Results
Authors: Weiss Jan-Peter , Xia-Serafino Wei
Published: March 2020

We present status and atmospheric retrieval results for the FORMOSAT-7/COSMIC-2 (COSMIC-2) mission. COSMIC-2 mission jointly managed by NOAA and Taiwan's National Space Organization (NSPO) and consists of six satellites launched on June 25, 2019 into a 24-degree inclination orbit. The primary payload is the JPL developed Tri-GNSS Radio-occultation System (TGRS). Tracking data from two upward looking precise orbit determination antennas are used for orbit and clock determination as well as ionospheric total electron content retrieval. Two limb-viewing radio occultation antennas provide more than 4000 daily profiles of the neutral atmosphere (e.g. bending angle, refractivity and temperature) from typically 60 km to 1 km above the Earth's surface. The secondary payloads are the Ion Velocity Meter (IVM) and tri-band Radio Frequency Beacon (RFB). The UCAR data processing center receives level-0 data from a set of downlink stations and processes them into higher level weather and space weather products in near real-time and post-processing modes. Products are transferred in near real-time to NOAA, NSPO, and operational weather centers worldwide. In this presentation we summarize mission/instrument status and summarize science results from the cal/val and initial operating phases of the mission. Results presented will include geographic coverage, neutral atmosphere profile quality and impacts on numerical weather prediction, as well as space weather product evaluation. We conclude with future activities and timelines.
How essential of the balance between large and small scale features to reproduce precipitation during a sudden sharp turn from drought to flood
Authors: Ma Yuanyuan
Published: March 2020

Sudden turn from drought to flood (STDF) is a unique representation of intra-seasonal extreme events and occurs frequently. However, it is notoriously difficult to represent in climate simulations due to the accumulation of model errors. This study uses a regional climate model (RCM) with different initialization and nudging schemes to explore effective approaches for capturing a STDF event. Results show that the conventional continuous integration with single initialization cannot reproduce the STDF event, while nudging or re-initialization can. Furthermore, spectral nudging and re-initialization outperform the conventional continuous simulation in reproducing precipitation features, but grid nudging induces the largest biases for precipitation though it has the smallest biases for other meteorological elements. Scale separation analysis shows that the large-scale features of the conventional continuous simulation drift far from the actual fields and force erroneous small-scale features, whereas the nudging and re-initialization successfully prevent the model from drifting away from the forcing fields at large-scales. The different performance for simulating precipitation among spectral nudging, re-initialization and grid nudging can be attributed to that the former two methods generate their own small-scale information via the RCM, while grid nudging over-suppresses the small-scale information while retaining the large-scale features. The difference in small-scale features affects the simulation of different moisture fluxes and convergences, as well as clouds, and then results in diverse precipitation. These results illustrate that both the consistency with large-scale features and the local variability from small-scale features are both robust factors for reproducing precipitation features during extreme events using RCMs.
Time series 30m resolution leaf area index estimation and vegetation change monitoring in Saihanba, China
Authors: Zhou Hongmin , Zhang Guodong , Wang Changjing , Wang Jindi
Published: March 2020

Leaf area index (LAI) is one of the most important biophysical variables for regulating the physiological processes of vegetation canopy. Time series high-resolution LAI data is critical for vegetation growth monitoring, surface process simulation and global change research. However, there are no high-resolution LAI data products that are continuous in time and space. In this paper, we use MODIS LAI products and Landsat surface reflectance data to generate time series high-resolution LAI datasets from 2000 to 2018 in Saihanba based on the ensemble kalman filter, and uses time-series LAI data to monitor surface vegetation changes according to the Prophet model. Firstly, the multi-step Savitzky–Golay filtering algorithm is used to smooth the MODIS LAI data, and the upper envelope of time series LAI is generated. A dynamic model is constructed according to the trend of LAI upper envelope to provide the short-range forecast of LAI. Then the ground measured LAI data and the corresponding Landsat reflectance data are used to train a Back Propagation neural network. High-resolution LAI data from BP model is used to update the dynamic model in real time to generate high-resolution time series LAI data based on EnKF. Finally, the time series LAI data is used as the input of Prophet deep learning model to obtain the LAI time series prediction values of a certain year. Comparing the prediction results with the LAI of current year, the correlation coefficient and the root mean square error distribution maps can be obtained, a support vector machine method is used to classify the disturbed pixels and the normal pixels. The LAI time series estimation has a high accuracy of R²larger than 0.90, and RMSE less than 0.54. The disturbance monitoring results indicate that vegetation in 2009, 2010, 2013, 2014, 2015, 2017 is seriously disturbed, Variation of meteorological conditions and deforest contributes heavily to the disturbance.
Irrigated sugarbeet yield, water use and water use efficiency responses to tillage practices
Authors: Jabro Jay , Stevens Bart , Iversen bill , Allen brett , Sainju Upendra
Published: March 2020

Better management practices have been used to increase soil water storage and reduce evaporation from the soil surface to optimize crop water use efficiency (WUE) in irrigated agriculture. A field study was conducted to evaluate the effect of  conventional tillage (CT), No-till (NT) and strip tillage (ST) practices on yield, water use (WU) and WUE of sugarbeet (Beta vulgaris L.) on a clay loam soil under over-head sprinkler irrigation system in the northern Great Plains. Tillage treatments were replicated five times in a randomized block design. Seasonal WU and WUE for sugarbeet root and sucrose yield were determined for the 2018 and 2019 growing seasons according to the water balance and WUE equations under three tillage practices. Results showed that no significant differences due to tillage treatment were found for crop WU, root yield, sucrose yield, and WUE for sugarbeet root and sucrose in 2018 and 2019 growing seasons. In 2019, the average value of WU across three tillage systems (616 mm) was significantly greater relative to 2018 (468 mm) due to atypical large rainfalls (218mm) occurred in September of 2019. Consequently, WUE values for both root and sucrose yield in 2019 under CT, NT, and ST were significantly greater than those in 2018. While NT and ST practices are promising alternative to CT for agricultural production in this region, further research is needed prior to making any recommendation.
High-resolution constraints on LAB structure at the Blanco transform
Authors: Hawley William , Gaherty James
Published: March 2020

Detailed knowledge of the seismic structure, fabric, and dynamics that surround the oceanic LAB continue to be refined through offshore seismic studies. Previous high-resolution studies in the Pacific basin far from plate boundaries show asthenospheric fabric that aligns neither with the lithospheric fabric (the paleo-spreading direction) nor with absolute plate motion, but rather in between. Here we present preliminary results from the Blanco Transform and Cascadia Initiative experiments, investigating the structure of the Juan de Fuca and Pacific plates on either side of the Blanco Transform. We measure ambient-noise and teleseismic Rayleigh-wave phase velocities, and solve for the period-dependent azimuthal anisotropy on either side of the transform. We will contextualize and interpret the fabrics based on mantle flow inferred from these previous Pacific basin studies. 
New Connections Between Tropical Dynamics and Lower Stratospheric Chemistry
Authors: Wilka Catherine , Solomon Susan , Cronin Timothy , Kinnison Douglas , Garcia Rolando
Published: March 2020

Matsuno-Gill circulations arising from tropospheric heating have been widely studied in tropical meteorology, but their impact on stratospheric chemistry and composition has seldom been explicitly evaluated. We show how anticyclonic Rossby wave gyres that form near the tropopause due to equatorially-symmetric Matsuno-Gill heating in near-equinox months provide a mechanism to influence chemistry in the tropical and subtropical upper-troposphere/lower-stratosphere (UTLS). This heating both generates anticyclonic flow in the lower stratosphere, which entrains extratropical air from higher latitudes deeper into the tropics of both hemispheres, and induces cooling in this already cold region. These two aspects of the circulation combine to allow heterogeneous chlorine activation on the surface of sulfuric acid aerosols to proceed rapidly. We use reanalysis to show that these Matsuno-Gill heating and wind response patterns are present in the months of interest, and then demonstrate that, in the WACCM model, they can substantially influence the distributions of species related to chlorine activation such as ClO and NO2. This provides a potential target for future tropical UTLS observation campaigns, and demonstrates a previously unrecognized mechanism in near-equinox months for dynamical influences on the spatial structures of atmospheric composition changes in this region. 
Using UAV and drilling to detect Quaternary activity of the Zhuozishan West Piedmont Fault, provides insight into the structural development of the Wuhai Basin and Northwestern Ordos Block, China
Authors: Liang Kuan , Ma Baoqi , Tian Qinjian
Published: March 2020

The Wuhai Basin is in the northwestern corner of the Ordos Block. Analyzing the geometry, and kinematic and dynamic characteristics of the boundary fault, the Zhuozishan West Piedmont Fault (ZWPF), will elucidate the regional tectonic environment and guide earthquake prevention and disaster reduction projects. Six presentative sites were selected for topographic measurements, from northern, middle and southern parts. Displacements of the ZWPF were calculated by measuring the top surface elevation of a widely distributed lacustrine layer in the footwall from outcrops at the sites (using UAV), and in the hanging wall from boreholes. The vertical slip rate of the ZWPF was then calculated based on the displacement and age of the lacustrine layer. Three to four normal fault-controlled terraces have developed on the footwall of the ZWPF, and the top surface of the lacustrine layer is at 1092–1132 m elevation. Data from boreholes showed that the top surface of the lacustrine layer is at an elevation of 1042–1063 m in the hanging wall. Vertical slip rates since 70 ka were estimated as 0.5±0.2 to 1.0±0.2 mm/a. The highest rate of vertical slip was observed at Fenghuang Ridge, in the central part of the fault system, and the vertical slip rate reduced to the south. In the northern Wuhai Basin, normal faulting still controls the piedmont landscape. However, NW-SE trending reverse faults and secondary folding have resulted from dextral strike-slip movement of the fault. The Wuhai Basin developed as a dextral-tensional negative flower structure. This study indicated that stress conditions of the northwestern margin of the Ordos Block include NE–SW compression and NW–SE extension, and an S-shaped rift zone has dominated the scale, structure, and evolution of the Yinchuan, Wuhai and Hetao Basins, and the active mode of faulting in these basins.
Introduction to A Regional Coupled Forecasting System
Authors: Li Mingkui , Zhang Shaoqing
Published: March 2020

A regional coupled prediction system for the Asia-Pacific area (AP-RCP) has been established. The AP-RCP system consists of WRF-ROMS (Weather Research and Forecast and Regional Ocean Model System) coupled models combined with local observing information through dynamically downscaling coupled data assimilation. The system generates 18-day atmospheric and oceanic environment forecasts on a daily quasi-operational schedule at Qingdao Pilot National Laboratory for Marine Science and Technology (QNLM). The AP-RCP system mainly includes 2 different coupled model resolutions: 27km WRF coupled with 9km ROMS, and 9km WRF coupled with 3km ROMS. This study evaluates the impact of enhancing coupled model resolution on the extended-range forecasts, focusing on forecasts of typhoon onset, and improved precipitation and typhoon intensity forecasts. Results show that enhancing coupled model resolution is a necessary step to realize the extended-range predictability of the atmosphere and ocean environmental conditions that include a plenty of local details. The next challenges include improving the planetary boundary physics and the representation of air-sea and air-land interactions when the model can resolve the kilometer or sub-kilometer processes.
Stable and Unstable Shear in Altered Downgoing Slabs: Predicted Strain Localization in Magnesian Carbonates and Wadati-Benioff Seismicity
Authors: Prakash Abhishek , Holyoke III Caleb W , Kelemen Peter B , Lamb William M , Kirby Stephen H , Kronenberg Andreas K
Published: March 2020

Seismicity of subduction zones at upper-mantle depths is commonly explained by dehydration reactions of serpentine and hydrous silicates and reductions in effective pressure. However, the conditions of Wadati-Benioff zone seismicity do not strictly correspond to temperatures and depths of serpentine dehydration, and there is no independent evidence that seawater penetrates the lithosphere to form serpentine at depths >30km below the seafloor. Altered lithosphere may contain magnesian carbonates in addition to hydrous silicates, both at the top of plates, where CO2 of seawater reacts with mantle rocks and at the base of plates where CO2 is introduced by mantle plumes.

Adapting the thermal softening model of Kelemen and Hirth (2007), we model the strain localization and shear heating within magnesite horizons embedded within an olivine host using flow laws determined experimentally for dislocation creep and diffusion creep of the carbonate layer and olivine host (Hirth and Kohlstedt, 2003; Holyoke et al., 2014). Strain rates predicted within carbonate-rich layers of downgoing slabs are much higher than those of the surrounding olivine at all conditions. However, shearing may be either stable or unstable depending on the relative rates of shear heating and conductive heat loss from the shear zone. Localized strain rates reach a steady state when shear heating and heat flow are balanced, while unstable strain rates are calculated where shear heating exceeds heat flow. Modeled strain rates accelerate to 10+1 s-1, as temperatures reach melting conditions, and stresses drop, corresponding to a seismic event. Applications of this model to the double Benioff zones of the NE Japan trench predict unstable seismic shear for both upper and lower seismic zones to subduction depths of ~300 km. For cold downgoing slabs, such as the Tonga subduction system, unstable seismic shear is predicted for carbonate horizons of altered downgoing slabs to depths exceeding 400 km.
Building regression models to estimate tree traits influential to slope stability
Authors: Lee Hsin-Tien , Song Guo-Zhang M. , Chang Li-Wan , Chen Cang-wei , Hu Hung-Yen
Published: March 2020

ABSTRACT     The above-ground (shoot) system of trees can affect slope stability through effects of infiltration facilitation, surcharge and wind loading. The amount of stem flow that infiltrates into soils is determined by diameter at root collar (DRC) of trees. Tree weight (surcharge) is a function of their heights (H) and diameters at breast height (DBH). Wind loading is related to crown area (CA) of trees. To save efforts for measuring all of these traits, we aimed to build regression models which allow researchers to estimate the other three traits with DBH. The study site was located in the Lienhuachih Forest Dynamics Plot, central Taiwan. DBH, DRC, CA and H of 20-30 individuals for the 18 most dominant tree species were measures. Trees which have been snapped off were excluded. Results showed that the regression models between DRC and DBH were linear. The models of CA against DBH and H against DBH was best built with allometric models, indicating that CA and H stop to increase with DBH once DBH reach to a certain size. In terms of model performance, the models of DRC against DBH was best (r2= 0.48- 0.97), followed by those of H against DBH (r2= 0.32- 0.89). The relatively poor performance of CA against DBH models (r2= 0.15- 0.93), especially for light-demanding tree species, indicated the need of incorporating light environment (i.e. crown illumination index) into regression analysis.

 

Key word：allomeric model, broad-leaved forest, diameters at breast height, landslide, Lienhuachih
Real-time Japanese nearshore wave prediction for one-week later using GMDH and global wave forecast data
Authors: Kim Sooyoul , Chiyonobu Keishiro , Mase Hajime , Takeda Masahide
Published: March 2020

The present study addresses how one-week later nearshore wave heights and periods are predicted by using a machine learning technique and global wave forecast data. For the machine learning technique, Group Method of Data Handling (GMDH) is used. The GMDH uses computer-based mathematical modeling of multi-parametric regression characterized by fully automatic structural and parametric optimization first introduced by Ivankhnenko (1971). The algorithm of GMDH can be described by a self-selecting procedure deriving a multi-order polynomial to predict an accurate output. Since its procedure is similar to a feed-forward transformation, the algorithm is called a Polynomial Neural Network (Onwubolu, 2016).

For the global wave forecast data, the datasets released by the Japan Meteorological Agency (JMA), National Oceanic and Atmospheric Administration (NOAA), and European Centre for Medium-Range Weather Forecasts (ECMWF). The global wave forecasts are generally available every 6 hours, with forecast out 180 hours in the future. However, since timely available forecasts are produced on synoptic scaled calculation domains, a consistent level of predictive accuracy at specific locations along Japanese coasts cannot be expected from the viewpoint of spatial resolution.

The present study aims to aid harbor and marine construction by establishing a nearshore wave prediction model for 14 stations around Japan that forecast up to one week in the future.

When the GMDH-based wave model uses the input data of global wave data by NOAA and ECMWF, the estimations of significant wave heights agreed well with observations. On the other hand, a combination of JMA and ECMWF wave data gave a good performance for significant wave periods. Since the present method transforms global wave prediction data into local nearshore waves by GMDH, it is possible at any concerned location where the nearshore wave observations can be obtained for the training of GMDH.
The three-dimensional ionospheric tomography in Japan by using the adaptive Kalman Filter algorithm
Authors: Song Rui , Hattori Katsumi , Yoshino Chie
Published: March 2020

  The three-dimensional (3-D) tomographic inversion is a crucial technique for imaging the ionospheric electron distributions (IEDs) on both the horizontal and vertical directions based on the total electron content (TEC) data. In this study, a regional 3-D tomography was realized in Japan using the Kalman Filter (KF) algorithm. In addition, to deduce the divergences, the adaptive Sage-Husa KF (SHKF) was proposed to determine the unknown priori information of the noise covariance encountered in the conventional KF (CKF). From this base, slant TEC (STEC) data observed by 55 GPS (Global Positioning System) receivers in the years of 2013 and 2018 was selected for IED reconstructions with the resolution 1º×1º×30 km in latitude, longitude and altitude, respectively. As for the ionospheric diurnal and annual variations, by comparing the F2 layer peak electron density (NmF2) simulated by SHKF, CKF, and the International Reference Ionosphere (IRI) model with the observed values detected by 4 Japanese ionosondes (Okinawa, Yamagawa, Kokubunji, and Wakkanai) during April 3-9, 2018 and 2013, the Root-Mean-Square-Error (RMSE) and co-releation index (ρ) were adopted to evaluate the simulated effciency. Results showed that the least RMSE (0.3084 in 2018, 0.5397 in 2013) and the best ρ values (0.9517 in 2018, 0.9896 in 2013) were both given by the SHKF-CIT method. Then, seasonal characteristics were implemented on January 02, March 20, June 14 and September 24, 2018, where the variations of northern EIA, winter and semiannual anomalies were accurately captured by the SHFK method. Meanwhile, the recalculated TEC values as well as the inverted vertical profiles manifested that SHKF-based tomography was outperformed the other methods. In the end, taking a strong geomagnetic storm happened on 26 August, 2018 as an example, both the meridional and latitudinal (along 135°E and 35°N, respectively) IEDs displayed more significant promotions than IRI model, and the results indicates that the IED around Japan developed by SHKF-based tomography is promising for the ionospheric studies and practical applications.
Layout optimization for a large offshore wind farm using Genetic Algorithm
Authors: Reddy K Narender , Roy S Baidya
Published: March 2020

Wind Farm Layout Optimization Problem (WFLOP) is an important issue to be addressed when installing a large wind farm. Many studies have focused on the WFLOP but only for a limited number of turbines (10 – 100 turbines) and idealized wind speed distributions. In this study, we apply the Genetic Algorithm (GA) to solve the WFLOP for large wind farms using real wind data.

The study site is the Palk Strait located between India and Sri Lanka. This site is considered to be one of the two potential hotspots of offshore wind in India. An interesting feature of the site is that the winds here are dominated by two major monsoons: southwesterly summer monsoon (June-September) and northeasterly winter monsoon (November to January). As a consequence, the wind directions do not drastically change, unlike other sites which can have winds distributed over 360o. This allowed us to design a wind farm with a 5D X 3D spacing, where 5D is in the dominant wind direction and 3D is in the transverse direction (D- rotor diameter of the turbine - 150 m in this study).

Jensen wake model is used to calculate the wake losses. The optimization of the layout using GA involves building a population of layouts at each generation. This population consists of, the best layouts of the previous generation, crossovers or offspring from the best layouts of the previous generation and few mutated layouts. The best layout at each generation is assessed using the fitness or objective functions that consist of annual power production by the layout, cost incurred by layout per unit power produced, and the efficiency of the layout. GA mimics the natural selection process observed in nature, which can be summarised as survival of the fittest. At each generation, the layouts performing the best would enter the next generation where a new population is created from the best performing layouts.

GA is used to produce 3 different optimal layouts as described below. Results show that:

A ~5GW layout – has 738 turbines, producing 2.37 GW of power at an efficiency of 0.79

Layout along the coast – has 1091 turbines, producing 3.665 GW of power at an efficiency of 0.82.

Layout for the total area – has 2612 turbines, producing 7.82 GW of power at an efficiency of 0.74.

Thus, placing the turbines along the coast is more efficient as it makes the maximum use of the available wind energy and it would be cost-effective as well by placing the turbines closer to the shores.

Wind energy is growing at an unprecedented rate in India. Easily accessible terrestrial resources are almost saturated and offshore is the new frontier. This study can play an important role in the offshore expansion of renewables in India.
Paleomagnetic and rock magnetic investigation in marine sediments, Nankai Trough, offshore Cape Muroto
Authors: Kars Myriam , Fukuta Tetsuya , Becker Carina
Published: March 2020

The Nankai Trough is an accretionary complex which extends over several thousands of kilometers along the Japanese Pacific coast. Many ocean scientific drilling expeditions have taken place in this zone to better understand the mechanisms of big earthquakes and generation of devastating tsunamis. Offshore Cape Muroto, Shikoku Island, is one of investigated zones. A recent International Ocean Discovery Program (IODP) expedition (IODP Expedition 370) in the area has focused on the temperature limit of life in deep subseafloor sediments. Here we present paleomagnetic and rock magnetic preliminary results on two neighboring sites in this zone drilled during two former Ocean Drilling Program (ODP) legs: Site 808 of ODP Leg 131 and Site 1174 of ODP Leg 190. At all sites, shipboard magnetostratigraphy was challenging because of a strong diagenetic alteration of the magnetic mineral assemblages. Four main downcore magnetic zones, characterized by specific magnetic properties and mineralogy, are identified. At Site 808, catagenesis of the organic matter has been proposed to explain the downcore rock magnetic properties. This explanation however could not stand for Site 1174. We present here a first attempt of a comparative paleomagnetic and rock magnetic study in high temperature marine sediments, off Cape Muroto.
Spatial and Temporal Patterns of Soil and Bedrock Groundwater Age and Age Tracer Concentration on Soil-Mantled Mountainous Hillslopes
Authors: Gardner W. Payton
Published: March 2020

The volume and scale of mountain-block groundwater circulation plays an important role in watershed hydrologic function; carbon, geochemical and nutrient budgets; and response to climate change.  However, mountain block groundwater remains one of the least understood components of the hydrologic cycle.  In this project, we investigate the role of bedrock groundwater circulation on groundwater age and isotopic tracer concentration on soil-mantled mountainous hillslopes.  We perform numerical modeling of variably saturated soil, saprolite and bedrock groundwater flow, groundwater age, and transport of a suite of environmental tracers including stable isotopes of water, tritium, dissolved CFC’s and SF6.  We use these models to investigate patterns of bed-rock groundwater circulation, and the distribution as well as integrated discharge of groundwater age and tracer concentration.  We identify first order processes controlling the spatial distribution and volume of groundwater circulation on hillslopes, the partitioning between slope parallel through-flow versus bedrock recharge, and the resulting hillslope age and tracer dynamics. Monte-Carlo simulations are used to evaluate the relative role of topography, soil characteristics, underlying lithology and antecedent moisture conditions in governing the age and tracer distribution. The basic relationships derived provide new insight into the role of bedrock groundwater recharge and discharge on hillslope age and tracer distribution.  Model results are compared with observed patterns of water level and stable isotopes measured in soil and bedrock groundwater on hillslopes in west-central Montana, United States. These results can be used to help hydrogeologists develop better conceptual models and estimates of bedrock groundwater circulation in upland catchments and its role in watershed hydrologic and biogeochemical function.
Cluster analysis of ultrafine particle size distribution based on long-term measurement at SORPES in Yangtze River Delta of China
Authors: Chen Liangduo
Published: March 2020

This work presents an overview of more than 3-year measurements of ultrafine particle size distributions (PSD, 6-800 nm) at a sub-urban site, the Station for Observing Regional Processes of the Earth System (SORPES) located in Nanjing, Yangtze River Delta of China. For the purpose of understanding the temporal variations as well as the source of ultrafine particles, k-means cluster analysis was applied and seven clusters were finally separated from the PSD data set. PSD spectra, hourly and seasonal frequencies of occurrence, the data of pollutant gases, PM2.5 and chemical composition, as well as metrological parameters were used to define and interpret each cluster. In general, four clusters (i.e. C1, C2, C3, and C4) were related with new particle formation (NPF) and growth, but they were at different stages or with different intensity, accounting for 20.4% of total PSD data; One (i.e. C5) was attributed to clean regional background, with high level of relative humidity, accounting for 37.9% of total data; Two clusters (i.e. C6 and C7) were polluted clusters, accounting for 41.6% of total data. Two extremely polluted episodes in C6 and C7, respectively, one was caused by fossil fuel combustion and another was caused by biomass burning, were selected as case study. The PSD of two polluted episodes was totally different, even though the mass concentration was similar. The associations between each clusters were analyzed, showing that the contribution of NPF to pollution and the conversion between clean and pollution because of accumulation and wet deposition.
The 2016 Mw 7.8 Kaikoura earthquake and its relationship to tremors.
Authors: Romanet Pierre , Aden-Antoniow Florent , Ide Satoshi
Published: March 2020

The relationship between slow earthquake and regular earthquake is fundamental question in seismology. It was already shown that some slow slip event may have led to some megathrust event. In return, passing surface wave from earthquake may also trigger tremors and slow slip event. Documenting these possible triggering effects between slow and fast events is of primary importance to understand them.

In this study we will focus more particularly on Marlborough region, in a region that was subject to the Mw 7.8 2016 Kaikoura earthquake. Two years before Kaikoura earthquake, we observed a Northeast to Southwest migration of tremors, getting closer to the hypocenter of Kaikoura earthquake. Despite being speculative, this may indicate that a slow slip event is happening shortly before Kaikoura earthquake, which is also supported by a small signal in two GPS stations nearby. After the earthquake, the rate of tremors increased in the region. Studying the relationship between tremors and the Kaikoura earthquake may provide some information on the role of the subduction in the region, as well as provide a new documented interaction of slow earthquakes with a crustal earthquake.

To detect and locate tremors, we use broadband and shortband velocity traces from the GeoNet network. The traces are bandpass filtered between 2-8Hz, and transform into envelope. Then we apply a classic cross-correlation technic to detect and locate the events. To remove unexpected events (i.e.: earthquakes), we used a criteria base on seismic energy and duration. Finally, we manually check each velocity traces and spectrograms.
The rheology of talc at high P-T conditions with implications for subduction-zone dynamics
Authors: Boneh Yuval , Pec Matej , Hirth Greg
Published: March 2020

Subduction-zone dynamics, kinematics, and seismicity are strongly affected by the rheology of hydrous phyllosilicates. Although there is growing evidence for hydrous minerals in the subducting plate, mantle wedge, and the interface between the plates, we are continuing to learn more about the rheological behavior of phyllosilicates at the relevant pressures. Talc is stable to depths of ≈100 km and has been found in fault rocks and subduction-zones mélanges as the product of metasomatism and/or mineral breakdown (e.g., breakdown of antigorite). The frictional strength of talc under low to intermediate pressures (up to ~400 MPa) was studied and demonstrated some of the mineral’s unique rheology; however, there is a lack of data for pressures of P > 0.5 GPa. Here we present the first rheological and microstructural analysis of experimentally deformed talc under pressure and temperature conditions relevant for the rheology of a subducted slab or mantle wedge.

We analyzed the mechanical and microstructural evolution of 15 samples of natural talc cylinders deformed using a high P-T deformation ‘Griggs’ type apparatus. We used natural samples comprise of >98 % talc and analyzed the post-mortem microstructure and chemistry of the samples using optical microscopy, scanning electron microscopy, and electron microprobe. The experiments were performed at confining pressures from 0.5 to 2 GPa and temperatures of 25 to 700°C; all within the talc stability field. Results show that the strength of talc at 25°C or 400°C is pressure-dependent up to the highest pressure tested (2 GPa). This behavior is attributed to brittle/semi-brittle mechanisms. At higher temperatures (500-700° C) and above a pressure threshold the strength becomes independent of pressure (e.g., when P > 1 GPa at T = 600 ° C), indicating that dilatant cracking is suppressed at these pressures. However, microstructural analysis indicates that fracturing is evident in all samples at all conditions examined. Interestingly, samples deformed at higher temperatures (>600°C) show more localized deformation. A synthesis of results from this study and previously published studies demonstrate that the strength of talc only becomes temperature-dependent at higher pressures. It is suggested that an increasing P-T geotherm of a subducted slab is likely to induce weakening and localization of talc-rich layers with possible implications for the mechanism to induce/hinder regional seismicity and affect the plate-coupling between the subducted and riding plates.   
Land-atmosphere feedbacks reduce positive albedo forcing of afforestation
Authors: Cerasoli Sara , Yin Jun , Porporato Amilcare
Published: March 2020

Thanks to their carbon uptake potential, which produces a negative radiative forcing, forests are considered a major natural mitigation strategy for global warming. Because of their relatively low albedo, however, previous assessments have shown that the effectiveness of afforestation rapidly decreases with latitude. Here, we revisit the problem by taking land-atmosphere feedbacks into account and especially the impact of vegetation on the timing of cloud formation and the probability of convective precipitation. Using a soil-plant-atmosphere continuum model coupled to a mixed layer model of the atmospheric boundary layer (ABL), we explore variations in the local surface energy balance and diurnal evolution as a function of biomes and latitude. We show that the increased evapotranspiration from forests causes an anticipation in the crossing between the ABL and the lifting condensation level a phenomenon that can lead to earlier cloud formation. This provides an extra cooling effect, which counterbalances the positive forcing of land-surface albedo. As a result, the negative effects of albedo changes appear less limiting, making afforestation a more viable strategy in a wider range of latitudes.  
The seasonal correlation between atmospheric water vapor and aerosol extinction and the relationship between aerosol, NO2, SO2 and water vapor during haze pollution in Qingdao, China
Authors: Ren Hongmei , Li Ang , Hu Zhaokun , Huang Yeyuan , Xu Jin , Xie Pinhua
Published: March 2020

MAX-DOAS observations was carried out from March 1, 2019 to December 31, 2019 in Qingdao, China, to measure the O4, NO2, SO2 and H2O absorption, to retrieve AOD and the troposphere vertical column concentration of NO2, SO2 and H2O.We use PriAM algorithm which based on the optimal estimation to calculating volume mixing ratio profile of trace gases, aerosol and water vapor during 0 ~ 4 km. The correlation between AOD and H2O VCD was analyzed in every month, the results showed that the AOD and H2O VCD has good linear relationship in each month., illustrate the increase of water vapor concentration will lead to the increase of moisture absorption of aerosol. The seasonal variation of the four seasonal correlation slopes in the order of summer < autumn < spring < winter. The influence of concentration change of NO2 VCD, SO2 VCD, H2O VCD and AOD is discussed in a haze episodes occurred in December 2019. Discovery that the H2O VCD and AOD was increased at the same time in the haze pollution incident, but with the increase of water vapor concentration, the concentration of NO2 and SO2 decreases, indicated that due to the increase of concentration of water vapor, NO2 and SO2 heterogeneous reaction will happen to generate nitrate and sulfate aerosols, so that the concentration of NO2 and SO2 concentration was decreased. The relationship between NO2, SO2, AOD and water vapor mixing ratio of 50m, 200m, 400m and 600m during haze pollution period was also studied, and it was indicated that phenomenon aerosol extinction increased with the increase of water vapor mixing ratio, while NO2 and SO2, on the contrary, were more obvious at 50m and 200m near the ground.