bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification of Rural Areas by Typology : A Case Study of Yunlin & Chiayi, Taiwan
Authors: Yang Hsin , Chang Hsueh-Sheng
Published: March 2020

In the past, Taiwan's spatial planning has focused on the development of urban areas and overlooked rural areas, which has led to difficulty in promoting rural-urban relationships. This study suggests that rural areas should not just be seen as single entities, but as a collection of distinct areas. Since it is becoming important to develop a new spatial planning in Taiwan, this study examines territorial space structure from a regional perspective, with a focus on the development of the rural areas of Yunlin & Chiayi. Consequently, this study aims to classify rural areas by the procedure of typology, in terms of their development dynamics, location, and economic structure, selecting appropriate indicators for each focus of inquiry. The study then uses cluster analysis, accessibility analysis and overlay analysis methods to classify information about these rural areas. This approach will show the differences in their spatial characteristics along with their histories of development through time, as well as the relationship between these rural areas and the overall region in which they are situated. It is hoped that this research will provide a more accurate description than currently exists of the rural areas studied in this paper, and that this information will be a useful resource to those who are developing new plans and policies, so that better integration can occur between urban and rural in Taiwan.
Changes in temperature and heat waves over Africa using observational and reanalysis datasets
Authors: Engdaw Mastawesha Misganaw , Hegerl Gabriele C , Steiner Andrea K.
Published: March 2020

Aiming to provide comprehensive information for climate change at regional level, we assess temperature and heat waves and their spatiotemporal trend and time of emergence over different regions of the African continent.  We analyze observational data of Climate Research Unit Time Series version 4.03 (CRU TS) and the three state-of-the-art reanalysis datasets; European Center for Medium-Range Weather Forecasts Reanalysis 5 (ERA5), National Oceanic Atmospheric Administration’s Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) and the Japanese Meteorological Agency’s 55 years reanalysis (JRA-55). We assess changes in monthly mean temperature and the agreement between observations and reanalyses. Changes in heat waves are analyzed based on reanalysis datasets because of their high temporal resolution. Heat waves are defined using absolute and relative thresholds, the number of summer days, tropical nights, the percentage of days with maximum and mean temperature above the 90th percentile, the warm nights and the warm spell duration index.  The results show increasing trends in monthly mean temperature in all four regions of Africa with different rate of change. A statistically significant trends in heat waves is found in all the regions.  Years of highest heat wave occurrence are identified in 2010 for Northern and Western Africa and 2016 for Eastern and Southern Africa. Minimum-temperature based indices, tropical nights and warm nights, show the highest increase in decadal trends and earliest time of emergence, respectively.

Key words: climate change; temperature; heat waves; time of emergence; reanalysis; Africa
Digital rock physics and laboratory considerations on a high-porosity volcanic rock
Authors: Schepp Laura L. , Ahrens Benedikt , Balcewicz Martin , Duda Mandy , Nehler Mathias , Osorno Maria , Uribe David , Steeb Holger , Nigon Benoit , Stöckhert Ferdinand , Swanson Donald A. , Siegert Mirko , Gurris Marcel , Saenger Erik H.
Published: March 2020

Microtomographic imaging techniques and advanced numerical simulations are combined by digital rock physics (DRP) to obtain effective physical material properties. The numerical results are typically used to complement laboratory investigations with the aim to gain a deeper understanding of physical processes related to transport (e.g. permeability and thermal conductivity) and effective elastic properties (e.g. bulk and shear modulus). The present study focuses on DRP and laboratory techniques applied to a rock called reticulite, which is considered as an end-member material with respect to porosity, stiffness and brittleness of the skeleton. Classical laboratory investigations on effective properties, such as ultrasonic transmission measurements and uniaxial deformation experiments, are very difficult to perform on this class of high-porosity and brittle materials.

Reticulite is a pyroclastic rock formed during intense Hawaiian fountaining events. The open honeycombed network has a porosity of more than 80 % and consists of bubbles that are supported by glassy threads. The natural mineral has a strong analogy to fabricated open-cell foams. By comparing experimental with numerical results and theoretical estimates we demonstrate the potential of digital material methodology with respect to the investigation of porosity, effective elastic properties, thermal conductivity and permeability

We show that the digital rock physics workflow, previously applied to conventional rock types, yields reasonable results for a high-porosity rock and can be adopted for fabricated foam-like materials. Numerically determined effective properties of reticulite are in good agreement with the experimentally determined results. Depending on the fields of application, numerical methods as well as theoretical estimates can become reasonable alternatives to laboratory methods for high porous foam-like materials.
Magmatic evolution in a sedimented margin and implications for lithospheric breakup: insights from high-resolution seismic data from the South China Sea
Authors: Zhang Cuimei , Pang Xiong , Su Ming , Zheng Jinyun , Li Hongbo , Gu Yale , Zhang Jiangyang , Zhao Yanghui
Published: March 2020

The interaction between magmatic and extensional processes related to the formation of rifted margins has been and still is highly debated. The interpretation of magmatic additions, timing of onset and budget of magma during rifting and lithospheric breakup remain controversial and poorly understood. In contrast, the emplacement of magmatic additions in rift systems with high sedimentation rates provides an exceptional perspective towards resolving some of these problems.

In this paper, we present two new high-resolution seismic profiles imaging the complete transition from the hyperextended crust to oceanic crust in the northern South China Sea (SCS). Based on the observation of magma-related structures and the interrelationship with the sedimentary sequence, we define forms and timing of magmatic additions. We show that magmatic activity initiated during necking and then propagated together with the seaward formation of “new” basement , as indicated by the occurrence of sills and laccoliths during hyperextension, and ENE striking cone-shaped volcanos during the final breakup stage before the establishment of an embryonic and then steady-state oceanic crust.

First order estimations of the magmatic budget in order to decipher the magmatic evolution show that it strikingly increased during final hyperextension and the breakup stage and lasted until 23.8 Ma. Thus, magmatic activity continued even after cessation of rifting. This study enables for the first time to provide a semi-quantitative estimate of when, where and how much magma formed during final rifting and breakup at a magma-intermediate margin.
Assessment of PRISMA imaging spectrometer data for the estimation of topsoil properties of agronomic interest at the field scale
Authors: Casa Raffaele , Pignatti Stefano , Pascucci Simone , Ionca Victoria , Mzid Nada , Veretelnikova Irina
Published: March 2020

On the 22 March 2019 the Italian Space Agency (ASI) launched the PRISMA satellite, having onboard a hyperspectral imager covering the 400-2500 nm range with 234 spectral bands and about 10 nm of bandwidth. The ground spatial resolution is 30 m, plus a panchromatic camera with 5 m spatial resolution. One of the potential application areas of this scientific mission is for precision agriculture applications, among which the mapping of field-scale variability of topsoil properties is of particular interest.

PRISMA clear-sky hyperspectral images were acquired in autumn and spring 2019 on the Maccarese farm in Central Italy, in the framework of the PRISCAV project, which is aimed at a first assessment of the PRISMA data. An intensive soil sampling campaign was performed, using a ground sampling scheme adapted to PRISMA and Sentinel-2 spatial resolutions, in the fields where bare soil was exposed at the satellite acquisition dates. Soil texture (clay, silt, sand), carbonates, pH and soil organic carbon (SOC) for the collected soil samples were then determined in the laboratory.

The dataset was then used to test calibration and validation of PLSR (Partial Least Squares Regression) and RF (Random Forest) models developed using PRISMA surface reflectance data. To this aim, several pre-treatment tests were performed, including pan-sharpening at 5 m using PRISMA panchromatic data as well as Sentinel-2 multispectral data.

The results show that the good results could be obtained in particular for clay estimation. The best-performing algorithm for topsoil properties retrieval using PRISMA hyperspectral data was RF algorithm as compared with PLSR.
Potential and Challenges of Investigating Intrinsic Uncertainty of Hydrological Models with Stochastic, Time-Dependent Parameters
Authors: Reichert Peter , Ammann Lorenz , Fenicia Fabrizio
Published: March 2020

The same observed precipitation falling onto seemingly the same initial state of a catchment will not lead to the same streamflow. The following causes are contributing to this non-deterministic behavior: (i) Unobserved spatial heterogeneity and limited time resolution of rainfall and other climatic observations limit the accuracy of observing the true input and other influencing factors. (ii) The knowledge about the initial state of the hydrological system is even more incomplete than about the input. (iii) Temporal changes in catchment properties that are not or not accurately described by the model also affect its response. As the same observed input can lead to different, unobserved internal states that affect streamflow for quite some time after a precipitation event, a description of such a system exclusively by considering input and output errors is not considering all relevant mechanisms. The description of such non-deterministic behavior (at the resolution of input and output observations) requires a stochastic model. To account for this apparent stochasticity of the system while still exactly maintaining mass balances, mass transfer processes should be made stochastic, rather than the mass balance equations. This can easily be done by turning the parameters of a deterministic, hydrological model into stochastic processes in time. As an additional advantage of this approach, the inferred time series of the parameters can be used to find relationships to input and model states that can (and have to) be used to improve the underlying hydrological model. On the other hand, the additional degrees of freedom for parameter estimation can lead to overparameterization, non-identifiability, and even “misuse” of “stochasticity” by “shifting” mechanistic relationships to the time-dependent parameter. These potential drawbacks require a very careful analysis.

In this talk, we will briefly review the methodology of stochastic, time-dependent parameters and investigate the potential and challenges of the suggested approach with a case study. In particular, we will demonstrate how we can learn about model deficits and how to reduce them, how the incautious application of the methodology can lead to (very) poor predictions, and how predictive cross-validation can help identifying whether the time-dependence of the parameters were “misused” to represent relationships that were not considered in the model or whether they can be assumed to represent true randomness.
The azimuth-dependent dispersion curve inversion method to extract 3D anisotropic structure and its application to the eastern Tibetan Plateau
Authors: Liang Chuntao
Published: March 2020

An azimuth-dependent dispersion curve inversion (ADDCI) method is applied to Rayleigh waves to extract 3D velocity and azimuthal anisotropy. The synthetic tests show that the ADDCI method is able to extract azimuthal anisotropy at different depths. The errors of the fast propagation direction (FPD) and the magnitude of the anisotropy (MOA) are less than 10° and 1-2%, respectively. The 3D anisotropic model shows large variations in the FPDs and MOAs with depth and blocks; strong contrasts are observed across major faults, and the average MOA in the crust is approximately 3%. The FPDs are positively correlated with the GPS velocity direction and the strikes of regional faults in most of the blocks. The low-velocity zones (LVZs) in the middle to lower crust are widely observed in the Songpan Ganze Terrence, the north Chuan-Dian block, and surprisingly in the Huayingshan thrust and fold belt. The LVZs in the middle crust are also positively correlated with the low-velocity belt in the uppermost mantle. These observations may suggest that large-scale deformation is coupled vertically from the surface to the uppermost mantle. Crust shortening by the pure shearing process, which involves the thrusting and folding of the upper crust and the lateral extrusion of blocks, may be the major mechanism causing the growth of the eastern Tibetan Plateau.
Coupling of the global hydrodynamic CaMa-Flood model with the ECMWF land surface model HTESSEL.
Authors: Dutra Emanuel , Yamazaki Dai , Mazzetti Cinzia
Published: March 2020

Rivers are a key component of the land hydrological cycle and are crucial in many societal activities and natural hazards. Historically, hydrological modeling has not been tightly associated with numerical weather prediction (NWP) due to the different communities involved, requirements and underlying processes. The increased skill of NWP has led to the uptake of weather forecasts in hydrological models, in particular for flood forecasting. At the same time, developments of Earth System Models (ESM), mainly driven by the climate community have lead to a tight integration of the land hydrological cycle. River discharge is a key quality indicator of the integrated water budget, and its use as a forecast skill metric of NWP has a large potential. Freshwater input to the ocean is also important for the ocean circulation, which becomes increasingly relevant with the current atmosphere-ocean coupling in NWP. Considering all these points, the representation of rivers and floodplains dynamics and their associated impact on inland water evolution is of interest for a wide range of applications currently addressed by global NWP. 

In this study we present the key technical developments to achieve a 1-way and 2-way coupling between the global hydrodynamic CaMa-Flood model and the land surface component of the European Center for Medium-Range Weather Forecasts (ECMWF) HTESSEL. The models coupling followed a single executable strategy, i.e. avoiding external couplers. A coupling interface was developed for CaMa-Flood that is independent from the driving model, while keeping the stand-alone configuration. The coupling is flexible, allowing both models to run at different spatial resolutions. The implementation allows for a flexible integration of the models and independent development, and can be applied to other models.  

The current representation of inland water bodies in HTESSEL (lakes) was driven by their impact in NWP, but without the representation of rivers it was not possible to have a consistent water budget. The coupling of CaMa-Flood allows for an integrated earth system model approach. Several options for the 2-way interaction between CaMa-Flood flooded areas in HTESSEL inland water bodies were investigated. Despite the consistent results, several challenges are identified in the representation of inland water bodies, their variability and impact on water cycle.
A novel application of triple oxygen isotope ratios of speleothems
Authors: sha lijuan , Mahata Sasadhar , Duan Pengzhen , Luz Boaz , Zhang Pu , Baker Jonathan , Zong Baoyun , Ning Youfeng , Ait Brahim Yassine , Zhang Haiwei , Edwards R. Lawrence , Cheng Hai
Published: March 2020

Triple oxygen isotope compositions have become one of critical proxies in characterizing a wide range of geochemical and hydroclimate processes. However, Δ17O (carbonate 17O anomaly) has only been barely used in the last decade because it is difficult to measure δ17O of natural samples to a sufficient precision in order to resolve small natural variability. In this study, we present triple oxygen isotope data from speleothems obtained by an O2-CO2 Pt-catalyzed oxygen-isotope equilibration method. The high precision (9 per meg or better, 1σ SD) of our new speleothem Δ17O data is sufficient to resolve subtle hydroclimatic signals. Based on this method, we established triple-oxygen-isotope records of TON cave in westerly region since the last 135ka, providing the evolution history of water vapor source and water vapor cycle in the orbit-millennium scale atmospheric precipitation in the Central Asia. In addition, the triple-oxygen-isotope records of speleothem from Asian and South American monsoonal regions were established in the key periods, such as glacial and interglacial periods. Our speleothem Δ17O data indicate a 20 per meg difference between Marine Isotope Stage 5d and 5e in samples from Central Asia, suggesting a shift in moisture source and/or fractionation history. Unexpectedly, there were no measurable Δ17O differences between glacial and interglacial samples from both the South American (western Amazon) and Asian (southern China) monsoon domains, implying consistent moisture-source conditions across glacial and interglacial cycles, at least in terms of relative humidity. Speleothem Δ17O data may thus provide new and important constraints for understanding regional and global hydroclimate dynamics.
Fault geometry and dynamics during the 1993-1998 uplift episode in Hengill, SW-Iceland
Authors: Blanck Hanna , Geirsson Halldór , Vogfjörd Kristín , Hjörleifsdóttir Vala
Published: March 2020

The Hengill volcanic complex in SW-Iceland is located on a triple junction where two extensive and one conservative plate boundary meet. An uplift event, possibly caused by a magmatic intrusion, in the 1990ies caused a landrise of 8 cm over the period of 4 years and was accompanied by more than 90.000, mostly very small, earthquakes. We used cross-correlation to improve pick accuracy and applied a relative relocation algorithm to get high resolution earthquake locations of the earthquakes in the direct vicinity of the centre of the uplift. Relocated earthquake location reveal clustering and alignments of earthquakes that are mostly oriented in NNE and ENE direction. Then we recalculated focal mechanisms for the new locations and then use the Quakelook software to select the best fitting focal mechanism. Quakelook calculates a plane that best fits the locations of a cluster of earthquakes which then is compared to the database of possible focal mechanisms that all explain the polarity and amplitude data similar well. The projection of the slip vectors into the fault plane is then used to estimate the average movement along the fault. From the fault dynamics we learn about the stresses activating that fault.

The relocated earthquake distribution shows that the stresses induced by the uplift event must have been small in comparison to the regional stress since the activated faults do not respect the geometry of the uplift source but are rather in agreement to the regional stress field. The uplift did not cause any new breaks in the crust but rather reactivated existing faults which sub-optimally oriented in relation to the uplift.
Drivers of the variability of dimethylsulfonioproprionate (DMSP) and dimethylsulfoxide (DMSO) in the Southern North Sea
Authors: Royer Colin , Borges Alberto V. , Lapeyra Martin Jon , Gypens Nathalie
Published: March 2020

The influence of abiotic and biotic drivers on the concentration of dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) was investigated and compared during two annual cycles in 2016 and 2018 within the Belgian Coastal Zone (BCZ, North Sea) at five fixed stations chosen to cover both the near-offshore gradient and a longitudinal gradient from the stations close to the Scheldt estuary to the most marine stations. Due to differences in light and temperature, significant differences of Chlorophyll a (Chl a) concentrations were observed between the two years with higher values in spring– and, to a lesser extent, in summer 2018 compared to 2016. The higher springtime phytoplankton biomass in 2018 compared to 2016 seemed to be related to better light conditions in early spring coupling with colder winter. Nevertheless, the seasonal and spatial DMS(P,O) patterns were nearly identical in 2016 and 2018. We then tested if the phytoplankton diversity based on genomic data and Chl a concentration could be used to predict the DMS(P,O)p concentration and better understand the observed variability in the field. The phytoplankton composition was characterized with high DMS(P,O) producers (mainly Dinophyceae such as Gymnodinium clade and Prymnesiophyceae with Phaeocystis sp.), occurring in spring, and low DMSP producers (various diatom species), occurring in early spring and in autumn, that influenced the most the DMS(P,O) concentrations observed in our field samples. We were able to estimate the DMSP concentrations with DMSP:Chl a ratio (mmol:g) for the main observed classes but the DMSO concentration was not properly assessed. The ratio used was not enough accurate to reproduce faithfully the interactions between the sulfur compound and the environmental stress.
Influence of regionally warm sea surface on moisture and extreme rainfall in Tsushima Strait during August 2013
Authors: Yamamoto Masaru
Published: March 2020

The present study investigates short-term (four-day) atmospheric response to regionally warm sea surface in Tsushima Strait for two periods (a sunny period, 19-22 August 2013 and a rainy period, 23-26 August 2013) using ensemble WRF simulations with initial condition altered in the presence and absence of an extremely warm SST core. In this presentation, the author focuses on the influence of regionally warm sea surface on moisture and extreme rainfall. The moisture response is quite different between the sunny and rainy periods. Ensemble averaged distribution of time-mean moisture variation induced by a regionally warm sea surface is well correlated with the SST increase during the sunny period. However, it is not clearly correlated with the SST increase during the rainy period when vapor fluctuated because of frequent rainfall. The high SST enhanced time-mean precipitation in the central area of the warm SST core. In the ensemble experiment, the warm SSTs do not always enhance hourly rainfall because the water-vapor concentrations are decreased by prior rainfall events in some members. In a simulation that well reproduces heavy rainfall at Izuhara located in Tsushima Strait in the presence of the warm SST core, high SSTs induced extreme precipitation (~50 mm/h) in the morning. Water vapor decreased after the morning heavy rainfall. The decreased moisture led to low precipitation in the afternoon. In contrast, a low-SST experiment with the warm-SST core removed shows that water-vapor concentrations were higher after weaker morning rainfall, compared to the high SST experiment with the warm core. Because of the high water-vapor concentrations, low SST led to greater precipitation in the afternoon. Thus, when responses of hourly precipitation to SST are investigated, we must consider the temporal water-vapor variation associated with prior rainfall event.
The coupling of dehydration and deformation results in localised fluid flow in the accretionary wedge – a novel study of calcite veins
Authors: Akker Ismay Vénice , Schrank Christoph E. , Jones Michael W.M. , Kewish Cameron M. , Berger Alfons , Herwegh Marco
Published: March 2020

In plate-convergent settings, fluid-saturated sediments dehydrate during subduction. The sediments are subsequently accreted to the upper plate. Along their dehydration-deformation path, the initial unconsolidated soft marine sediments become thick, foliated, impermeable meta-sedimentary sequences. Fluid flow through such ‘non’-porous low-permeability rocks is concentrated in fracture networks, ranging from the mm- to the km-scale. We study the interplay between ductile and brittle deformation processes and fluid flow by investigating calcite veins in slates from the exhumed European Alpine accretionary wedge across scales (µm to km). These slates experienced peak metamorphic temperatures between 200°C and 330°C and represent the transition between the upper aseismic and seismic zone. With the use of Synchrotron X-ray Fluorescence Microscopy (SXFM), we investigate the slates by visualizing trace-element distributions. This technique shows that alternating cycles of slow pressure-dissolution processes and brittle fracturing persist over long time scales. At the micron-scale, pressure solution of the initial carbonate-rich slates is indicated by an enrichment of newly recrystallized phyllosilicates on cleavage planes and in pressure shadows. These ductile deformation features are mutually overprinted by calcite veins (aperture 10 µm), which are nicely visualized with Sr-SXFM maps. Increasing compaction and recrystallization in the slate-rich matrix leads to progressed dehydration resulting in an increased pore fluid pressure and subsequent hydrofracturing. The micron-sized fractures are immediately filled in with minerals, which are oversaturated at that time in the fluid, resulting in the formation of (i) micron-veinlets. Micron-veinlets collect (ii) into mm-cm sized veins, which themselves form (iii) vein arrays and (iv) mega-arrays, respectively at the 50-100 m and 300-400 m scale. This upscaling of fluid pathways indicates a localised fluid transport through the accretionary wedge, which has important implications for the understanding of the mechanical stability of the accretionary wedge and related seismic activity.
Developing High-resolution Air Quality Reanalysis Dataset over China for Years 2013-2018 Based on Ensemble Kalman Filter and Surface Observations from CNEMC
Authors: Kong Lei , Tang Xiao , Zhu Jiang , Wang Zifa , Wu Huangjian , Li Jianjun
Published: March 2020

A six-year long high-resolution Chinese air quality reanalysis datasets (CAQRA) covering the period 2013-2018 has been developed in this study by assimilating over 1000 surface air quality monitoring sites from China National Environmental Monitoring Centre (CNEMC) based on the ensemble Kalman filter (EnKF) and the Nested Air Quality Prediction Modeling System (NAQPMS). This reanalysis provides the surface fields of six conventional air pollutants in China, namely PM2.5, PM10, SO2, NO2, CO and O3, at high spatial (15km×15km) and temporal (1 hour) resolutions. This paper aims to document this dataset by providing the detailed descriptions of the assimilation system and presenting the first validation results for the reanalysis fields of air pollutants in China. A twenty-fold cross validation (CV) method was used to assess the quality of CAQRA. The CV results show that the CAQRA has excellent performances in reproducing the magnitude and variability of the air pollutants in China with the biases (normalized mean bias) of the reanalysis data about -2.6 (-4.9%) μg/m3 for PM2.5, -6.8 (-7.6%) μg/m3 for PM10, -2.0 (-8.5%) μg/m3 for SO2, -2.3 (-6.9%) μg/m3 for NO2, -0.06 (-6.1%) mg/m3 for CO and -2.3 (-4.0%) μg/m3 for O3. The interannual changes of the air quality in China were also well represented by the CAQRA in terms of the six air pollutants. Comparisons with previous datasets of daily PM2.5, SO2 and NO2 concentrations indicate that the CAQRA is more accurate with smaller RMSE values. We also compared our reanalysis dataset to the CAMSRA (The Copernicus Atmosphere Monitoring Service reanalysis) produced by ECMWF (European Centre for Medium-Range Weather Forecasts), which suggests that the CAQRA has higher accuracy in representing the surface air pollutants in China due to the assimilation of surface observations. This reanalysis dataset can provide us comprehensive pictures of the air quality in China from 2013 to 2018 with a complete spatial and temporal coverage, which can be used in the assessment of health impacts of air pollution, validation of model simulations and providing training data for the statistical or AI (Artificial Intelligence) based forecast.
The consideration of storm durations in hydrological frequency analysis and design storm determination
Authors: Yin-Huan Mai , Gene Jiing-Yun
Published: March 2020

     For engineering practice, the determination of design storms mainly applies Intensity-duration-frequency method or revised ranking method with fixed given duration based on the long-term rainfall record. However, this kind of method does not address the influence of storm duration. Both long or short storms are combined together in performing frequency analysis. As a result, in some cases, the peak intensity of short duration design storm might be overestimated by traditional methods. Consequently, how to incorporate the concept of duration to improve current frequency analysis is essential to improve design storms are the two main purposes of this research. With this concern, this study tries to find better definitions of the rainfall characteristics based on different durations, and generate revised design storm in the consideration of more comprehensive rainfall patterns. For the purpose of flood control, this study tries to proposed the improved method based on a conceptual watershed with known drainage capacity. In the watershed, when the runoff exceeds this capacity, the accumulation of the surface runoff will become the flood water, and keep increasing with raining time. Considering this situation, the duration of storm plays an important role in the severity of flooding. For this concern, this study tries to incorporate two parameters, the peak intensity, and time that rainfall exceeds drainage capacity, to indicate the severity of storm. Following, to avoid the under/over-estimation of rainfall intensity without considering the influence of duration, we propose the data weight index to composed design storm by combining different duration rainfall events. More specifically, if the duration of rainfall event is similar to the design storm, the parameters of data will get a higher weight index to shape the rainfall characteristics of design. With this process, we can obtain the suitable parameters for our design storms and compare the risk of flood with any two storms with different duration in a same drainage capacity. Based on the equivalent risk of storms, we could transform the parameters of the rainfall with the same risk level even for different duration. By this way, this study will propose a method of design storms which offers a better application for flood protection plan and management.

 

Keywords: Design storm, Urban rainfall design, Hydrologic frequency analysis
Forecast-informed operation of transboundary water-energy systems: a case study in the lower Mekong River Basin
Authors: Dang Thanh Duc , Chowdhury AFM Kamal , Block Paul , Galelli Stefano
Published: March 2020

The ASEAN economic growth is one of the main factors driving the development of hydropower dams in the lower Mekong River Basin. Recent studies show that the performance of these infrastructures is uncertain and largely affected by both seasonal and inter-annual water availability. During El Niño years, for example, weaker monsoon rainfalls reduce the amount of available hydropower, which must be offset by a deeper reliance on fossil fuels. A potential solution to this problem stands in the idea of informing hydropower operations with seasonal hydro-meteorological forecasts. Here, we explore the value of forecasts through a computational framework consisting of three components. First, we use principal-component regression to predict seasonal cumulated precipitation at multiple sites within the Mekong basin. Second, we harness the information contained in the forecasts to optimize both firm and annual hydropower production of each dam; a result attained by coupling the Variable Infiltration Capacity hydrologic model with a Multi-Objective Evolutionary Algorithm. Third, we use the power system model PowNet to simulate the energy mix of Thailand and Laos, and thereby evaluate the forecast value in terms of reduced CO2 emissions and energy production costs. Modelling results for the period 1995-2004 show that the use of seasonal forecasts reduces annual operating costs and CO2 emissions by at least 10 million USD and 20 million tons, respectively.
Study of temperature, wind speed and tides in the upper atmosphere from optical measurements during the 2017-2019 winter's
Authors: Roman Vasilyev , Olga Zorkaltseva
Published: March 2020

Abstract.The mesosphere and lower thermosphere are the least studied areas of the earth atmosphere. The reason for this is the lack of monitoring. We have the Fabry-Perot interferometer (FPI) installed in middle latitudes of East Siberia in the geophysical observatory of Institute of Solar-Terrestrial Physics SB RAS (51.8N, 103.1E).  The FPI is a unique instrument and has no analogues in Russia.The FPI with a temporal resolution of about 10–15 minutes observes the natural glow of the night atmosphere of 630.0, 557.7 nm and 843 nm, the characteristic heights of these lines are about 250, 100 and 90 km, respectively. In this study, we use data on the behavior of the zonal, meridional component of wind speed and temperature obtained with 557.7 nm line. We analyze the temperature regime and dynamics of the stratospheric polar vortex according to the data of climatic archive - ERA-interim to get the relationship of SSW and wind regime in MLT.  In this study, we consider winter atmosphere in 2017-2019 over East Siberia, namely the period of sudden stratospheric warming. We compared the evolution of stratospheric warming’s with temporary variations in background wind and temperature and tides in the mesosphere and lower thermosphere. It turned out that the sudden stratospheric warming's made a strong effect in upper layers of the atmosphere. During major stratospheric warming's, the zonal and meridional winds reversed and increase in the semidiurnal and thirdrdiurnal tides. Temperature in MLT dramatic drop followed by an increase during sudden stratospheric warming's. Minor sudden stratospheric warming's had a similar (but much lower in intensity) response in the upper atmosphere.

Acknowledgements. Analysis of stratosphere condition in this work was supported by the Russian Science Foundation, project No. 19-77-00009. Analysis of methosphere condition in ths work was supported by Rusian Foundation for Basic Research project No. 18-05-00594. The measurements were carried out on the instrument of Center for Common Use «Angara» [http://ckp-rf.ru/ckp/ 3056]. The authors gratefully acknowledge the access to the ECMWF ERA-Interim.
Application of Python Script in National Geographic Conditions Monitoring Project of China
Authors: Zhai Zhaokun , Liu Jianjun , Gao Yin
Published: March 2020

The geographic conditions monitoring is an important mission in geosciences. Its aim is to study, analyze and describe national conditions in the view of geography. The National Geographic Conditions Monitoring Project of China, based on remote sensing and geospatial information technology, has acquired large-scale and various kinds of geographic data in China, such as remote sensing images, land cover information and geographic conditional elements. The goal of this project is to build National Geographic Conditions Monitoring Database, which is aimed to offer reliable fundamental geoinformation for government decision-making. It plays an important role in natural resources supervision, environmental protection and emergency management. Moreover, it also contributes to the development of geosciences. However, as China is such a huge country, large quantity of data is produced by many institutions and companies. It makes it difficult to finish data quality check manually before importing data into oracle spatial database. Besides, there are many data applications from lots of institutions every year, which also spends plenty of time.

Python is an open source computer programming language. It has the characteristics of friendly, clear syntax and easy to learn. There are large numbers of standard libraries and third-party libraries. Based on python, we developed lots of python scripts for this project. From the viewpoint of geodatabase construction, we developed scripts to check collected data, mainly include directory check, structure check, attribute check and topology check to ensure data is standardized and correct. Spatial analysis and statistical calculation can also be finished rapidly and accurately using python script. For production supply, we also developed scripts which can distribute data from database automatically according to any region.

Tools are critical to the progress and development of science. The application of python scripts improves the efficiency of our work to some extent, which can make sure the project is successfully completed on time every year. Geographic data is obtained that covered all over the country, which contributes to the economic and social development, national strategic decision and planning. The source code of these scripts is public. It also helps to optimize and improve these scripts. I believe open source software will play a greater role in the future. Geoscience will get better and better when geographic data is processed and analyzed using open source software.
Impacts of Stratospheric Intrusion on Surface Ozone over Eastern China
Authors: Wang Wuke
Published: March 2020

Ozone pollution is currently a serious environmental issue in China. Most of studies have attributed the surface ozone pollution over China to the strong photochemical production from anthropogenic sources. As another important source of tropospheric ozone, the stratospheric intrusion (SI), however, has been less concerned. This study investigates the SI events over the Yangtze River Delta in eastern China using the newest ERA5 (the fifth generation of ECMWF atmospheric reanalysis) meteorological and ozone data, the In-service Aircraft for a Global Observing System (IAGOS) ozone profiles and the station-based ground-level ozone measurements. Results indicate that SI plays important roles in spring and summer ozone pollution episodes over the Yangtze River Delta, eastern China. Based on CAM-Chem (the Community Atmosphere Model with Chemistry) and LPDM (Lagrangian Particle Dispersion Modeling) model simulations, we found that deep SIs contribute ~15 ppbv in spring and ~10 ppbv in summer to surface ozone variations in eastern China. A deep SI event occurred in 2018 spring associated with a strong horizontal-trough, which brought ozone-rich air from the stratosphere to the troposphere and resulted in severe surface ozone pollution over the Yangtze River Delta. From 7-year statistics, we found that strong SI events during summer are associated with a cyclonic valley between the South Asian High and the Subtropical High, accompanied by downward fast transport of ozone from the stratosphere to the troposphere. Our results provide important information for surface ozone prediction and control in eastern China.
ULF waves registered with the Ekaterinburg radar: Statistical analysis and case studies
Authors: Chelpanov Maksim , Mager Olga , Mager Pavel , Klimushkin Dmitri
Published: March 2020

A midlatitude coherent decameter radar installed near Ekaterinburg, Russia (EKB radar) has been operating since 2012. It is aimed at monitoring dynamics of the ionosphere–magnetosphere system in Eastern Siberia. A special operation mode is used at the radar to study ULF wave activity: three adjacent beams oriented approximately along the magnetic meridian are surveyed with time resolution of 18 s each. A number of wave observation events registered with the radar was analyzed and discussed in several papers. An overview of the main results from these studies is presented here.

A statistical study of more than 30 waves observed in the nightside ionosphere revealed that in the majority of the cases their frequencies are considerably lower than those of field line resonance (FLR) for appropriate magnetic shells and longitudinal sectors (FLR fundamental frequencies for each case were estimated based on spacecraft data). Thus, these waves cannot be associated with the Alfvén mode. It was assumed that at least part of them should be identified with the drift compressional mode. Indeed, in individual cases oscillations exhibited signatures of this mode: in one of the events a linear dependence of frequency on azimuthal wave number m at a fixed magnetic shell was found. Only the drift compressional mode can feature such dependence in the inner magnetosphere. For two other cases merging of drift compressional and Alfvén modes at some critical value of m was shown. A case of simultaneous spacecraft and radar wave observation accompanied by increases in energetic particle fluxes was shown. A modulation with the frequency of this wave was found for flux intensity of those energetic protons, whose phase velocity is close to that of the wave. This implies that the source of the wave was a drift resonance with the substorm injected protons.
Soil Quality and Health – can it be quantified?
Authors: Hassall Kirsty , Zawadzka Joanna , Milne Alice , Dailey Gordon , Harris Jim , Corstanje Ron , Whitmore Andrew
Published: March 2020

Soil quality and health (SQH) are terms used extensively to characterise soils. However, the exact definitions of quality and health are often qualitative with differing meanings to different stakeholders. Collecting and combining these differing viewpoints is a non-trivial task. In this work, we will discuss how we have used the Bayes Net framework to define a hierarchical structure that enables a subjective concept such as soil quality and health to be quantified from multiple sources of information including diverse sources of expert knowledge and linking this through to national databases.

Information within a Bayes Net is encapsulated through a set of conditional probability tables that describe the conditional dependencies of all variables of interest. It is well known that humans are particularly poor at estimating such probabilities which, when a Bayes Net relies upon experts from differing disciplines and stakeholders from disparate application areas to quantify their beliefs through these conditional probability tables, is often a major limitation to these techniques. Here, we demonstrate an elicitation web app that mitigates some of the difficulties associated with quantifying subjective opinion. Moreover, we show how an inference network of known associations aids in the extraction of information from increasingly subjective sources within the hierarchical framework.
Assessing temperature fingerprints for the Atlantic overturning in the past two millennia
Authors: Ermis Reyhan Shirin , Moffa-Sánchez Paola , Jahn Alexandra , Rehfeld Kira
Published: March 2020

The Atlantic Meridional Overturning Circulation (AMOC) is essential to maintain the temperate climates of Europe and North America. It redistributes heat from the tropics, and stores carbon in the deep ocean. Yet, its variability and evolution are largely unknown due to the lack of long-term direct circulation measurements. Previous studies suggest a connection between the variability of the AMOC strength and a temperature dipole in the North Atlantic. These results suggest a substantial decline in the strength of the overturning at the onset of the industrial era. 

Here we compare temperature reconstructions from four sediment cores in the North Atlantic with model simulations of the Community Earth System Model (CESM1) as well as the Hadley Centre Coupled Model (HadCM3) over the Common Era. By examining the correlation between the surface temperatures in the North Atlantic and the strength of the overturning we test the robustness of previously used temperature fingerprints. Analysing variability in the surface and subsurface temperatures as well as the overturning strength in models we assess possible drivers of variability in ocean circulation. We compare the persistence times and the time scale dependent variability of the AMOC, the surface and ocean temperatures in the model with those in the temperature reconstructions. The sub-surface reconstructions match with the 200m ocean temperatures in persistence times but not with the AMOC in the models. The surface temperatures in the models show persistence times similar to those obtained for the AMOC. However, time scale dependent variabilities in the surface temperatures do not match those found the AMOC. Therefore, temperature fingerprints might not be a reliable basis to reconstruct the ocean overturning strength.

Due to the systematic comparison of two models on different time scales and an assessment of surface to sub-surface temperatures this study could provide new insights into the variability of Atlantic overturning on decadal time scales and beyond.
A diachronous opening of the Iapetus Ocean in the Neoproterozoic
Authors: Robert Boris , Domeier Mathew , Jakob Johannes
Published: March 2020

The late Neoproterozoic is a time interval of dramatic changes affecting the biosphere, the cryosphere and the lithosphere, including the final disaggregation of the supercontinent Rodinia and the formation of Gondwana. The Iapetus Ocean opened during the breakup of Rodinia, i.e. resulting from the separation of the three major continental blocks: Laurentia, Baltica and Amazonia. Protracted continental extension to rifting from 750 to 530 Ma is observed along the involved continental margins and may indicate several ocean openings in addition to the Iapetus Ocean. Breakup timing is still much debated in the literature, as it remains unclear how to best interpret the fragmentary geological record along the rifted margins, and because only few reliable paleomagnetic data are available for this period of time. Three distinct times for the breakup are proposed for Laurentia and Amazonia: at (1) 750-700 Ma, (2) 615-570 Ma and (3) 550-530 Ma. Various terranes are also involved in the opening of the Iapetus Ocean and may have drifted along with or independently of Amazonia.

In this study, we reviewed the geological observations of each of the involved margins and the available paleomagnetic data from 750 to 520 Ma to test these scenarios. Paleomagnetic data from Laurentia and Amazonia-West Africa constrain the breakup age to occur before 575 Ma, discarding the possibility of a late Ediacaran/Early Cambrian opening. Geological observations, better preserved in Laurentia and Baltica, indicate two main phases of (attempted) continental rifting, from 750 to 680 Ma and from 615 to 550 Ma. The second phase is usually interpreted as leading to the breakup of Laurentia, Amazonia and Baltica, as in scenarios (2) and (3). Nevertheless, it cannot easily explain (i) the absence of the Central Iapetus Magmatic Province in West Amazonia, (ii) the dynamics of accreted terranes now observed in South America and (iii) the distinct late Neoproterozoic detrital zircon age population in Phanerozoic sediments along West Amazonia (which are moreover absent in East Laurentia). These observations are better explained by a model wherein Laurentia and Amazonia broke apart during the first rifting phase around 750-680 Ma. In this scenario, the second phase of rifting (615-550 Ma) leads, in the west, to drifting of small terranes southward and toward Amazonia, and in the east, to the final breakup between Laurentia and Baltica.