bluuebunny/crossref_metadata_2025 huggingface dataset:
Landscape rejuvenation controlled by neotectonic fault reactivation on Norway’s post-glacial rifted margin
Authors: McDermott Jeni , Redfield Tim
Published: March 2020

The sharp, asymmetric ‘Great Escarpment’ of southwestern Norway mimics landforms commonly associated with fault-controlled ‘footwall uplift’ mountain ranges, bringing into question whether climate-driven erosion and consequent mass redistribution can generate kilometer scale topographic relief, or if tectonic forces are required instead.  Here we report on patterns of relief and fluvial incision in a region characterized by glacial sculpting, rapid isostatic uplift, and a well-established brittle template of normal faults.

The Surna valley (Surnadalen) of mid-southern Norway is a SW-NE striking wide, alluvial, U-shaped valley whose SW margin defines part of the Great Escarpment. Surnadalen displays clear morphometric asymmetry: its inland (SE) side is defined by high elevation (>1000 m) and well-developed drainage networks that display clear evidence of alpine glacial carving, while its seaward side is lower (~500 m) and has neither developed drainage networks nor evidence for valley glaciers. Inland drainages display a distinct set of aligned knickzones that maintain characteristics inconsistent with transient fluvial response to deglaciation. Incision occurs across fluvial process zones with no correlation to drainage area, suggesting regional forcing rather than catchment-scale drivers. Both lithology and structure are nearly identical across greater Surnadalen, and no change in rock type or erodibility correlate with the incision zones. Incision is axially asymmetric: All knickzones occur at the base of the ‘Great Escarpment,’ and the Tjellefonna Fault Zone (TFZ), a strand of a regionally important fault complex, projects into Surnadalen’s axis and aligns directly with the knickzone trace. The depth of incision decays from SW to NE in the direction of propagation of the TFZ tip at a mathematically predictable rate. We interpret the knickzone alignment to reflect active normal fault control over incision localization and depth. The depth and morphology of incision suggests Surnadal’s incision survived multiple glacial cycles. This interpretation implies that Norway’s ancestral structural template continues to impose a fundamental control over the creation and maintenance of the Great Escarpment. Although fault reactivation is not the result of regional tectonic extension, but rather is likely the product of erosion-induced shifting of loads, the pre-existing margin architecture appears to dominate the isostatic response to erosion.
A new particle–by –particle hot plate technique for measurement of precipitation rate, snow density and visibility
Authors: Rees Karlie , Garrett Timothy , Singh Dhiraj , Pardyjak Eric , Reaburn Allan
Published: March 2020

The diameter, mass and density of individual falling snowflakes is being measured automatically in Salt Lake City, Utah using a new device called the  Differential Emissivity Imaging Disdrometer (DEID). Hydrometeor properties are obtained from the DEID using a temperature-controlled hotplate to melt and evaporate hydrometeors and a thermal camera based upon the large difference in thermal emissivity between water and the aluminum hotplate. The density of each particle is calculated from the initial effective diameter imaged by the thermal camera and the individual particle mass, by assuming conservation of energy for heat transfer from the plate to the melted droplet and measuring the time taken for evaporation. Simultaneously recorded Multi-Angle Snowflake Camera (MASC) imagery provides hydrometeor types. These data are revealing detailed structures of snowfall density suited for avalanche studies, atmospheric precipitation rate, snow water equivalent and visibility, and size, and the mass and density distributions of individual particles. Results are generally consistent with past studies by e.g. Marshall and Palmer, Marshall and Gunn and Locatelli and Hobbs. However, order one million particles can be collected in a single storm cycle, so the range of particle collected and the statistical validity of the analyses is providing new insights into the nature of frozen precipitation.
Development of performance indicators for Water-energy-food security and its application in Latin America and the Caribbean
Authors: Mahlknecht Jürgen , Gonzalez Ramon , Loge Frank
Published: March 2020

Understanding water-energy-food interrelatedness and interdependencies (WEF Nexus) over environmental resources can result in improved water, energy, and food security by integrating management and governance across sectors and scales, reducing tradeoffs, and building synergies, overall promoting sustainability and a transition to green economy. One of the most relevant research areas on the Nexus is the development of indexes to assess the performance of the three sectors and their interlinkages. These tools are essential to understanding the Nexus concept and to determine areas for improvement, especially in developing countries. To evaluate the WEF Nexus for a developing region, namely Latin America and the Caribbean (LAC), two approaches are proposed to evaluate water, energy and food security at intra-country level. First, a composite diagram was developed for LAC countries and subregions that considers three key indicators per sector: availability, access, and sustainability of the sector’s resources. Second, an analysis was performed for selected countries using internal factors that represent the most important interrelationships that exist within the WEF Nexus. The results show that access to food in LAC is relatively low in comparison to other developing regions. Regarding renewable energy sources, with the exception of some countries, the region’s share (including hydroelectricity) in electricity production is low. Water resources represent the most vulnerable sector for food and energy development of the countries (water for food, and water for energy), as well as the need to implement green infrastructure for sustainable water production (food for water).
Integrated dynamic interactive models of ore-magmatic concentres in Uzbekistan
Authors: Sidorova Irina
Published: March 2020

This study was made with complex geophysical and geological observations by the DSS-MRW seismic reflection and refraction profiles, which cross Uzbekistan. The aim of our study was to reveal new features, which are characteristic of the upper mantle rocks, related to morphology of bodies, their physical properties, consisting mainly in their contrasting values for contiguous blocks, and general increased velocity and density of the rocks they contain.  The methodology of establishment of integrated dynamic interactive models on ore-magmatic concentres consists of two consecutive stages including: 1) the methodology of integrated geological-geophysical processing and interpretation of potential fields and seismic profiles cross cutting ore-magmatic concentres; 2) the methodology of creation of a united interactive 3-D model in ArcGIS in combination with materials of remote sensing. Each of these stages is divided into more detailed sub-stages. During the study of the deep structure of ore-magmatic concentres, the first step is the integrated methodology of the processing and interpretation of potential fields. It is mainly orientated at the identification of positions of geometric borders of the division of mediums determined by the data of seismic exploration of preferably deep seismic sounding. Our experiences shows  that the use of these potential fields for the area zoning of the territory, identification of the depth of manifestation of isolated blocks and their density may significantly affect the interpretation of seismic exploration data. Therefore, the implementation of the method-based interpretation of data of gravitational and magnetic fields preceding, the stage of the construction of the integrated model enables a more complete use of opportunities of these methods. Anomalous objects are isolated in the Earth crust on the basis of the interpretation of potential fields using the methods of the solution of direct and inverse tasks. An integrated interpretation of potential fields enablers the maximal use of information available in this field for the analysis of the deep structure. The processing of data is an important integrated part of the whole process of development of the 3-D model of the ore-magmatic concentre within the frames of the GIS project. New regional features have been revealed: they include peculiarities of the Earth's crust's deep geological structure and spatial distribution of deposits; they are contact areas of the Earth's crust geoblocks with anomalously high and low seismic and density parameters. Mapping of these zones helps select new ways in the search for mineral deposits.

 
Paleoseismological trenching of the eastern Rhine Graben Boundary Fault: the Ettlingen segment
Authors: Reicherter Klaus , Baize Stephane , Hürtgen Jochen , Cinti Francesca , Rockwell Tom K. , Jomard Herve , Seitz Gordon , Ritter Joachim
Published: March 2020

Paleoseismic data on the eastern central Rhine Graben Boundary Fault, as part of the Upper Rhine Graben (URG) fault system, revealed Holocene earthquake activity with surface rupturing faults. The URG is one of the most seismically active areas in the stable continental interiors of Central Europe north of the Alps. We opened the first paleoseismic trenches N of Basel and S of Frankfurt along the ca. 300 km long eastern Rhine Graben Boundary Fault (RGBF). After extensive shallow geophysical and morphotectonic investigations and analyses, we discovered that the eastern central RGBF consists of several parallel fault strands that are marked by topographic steps, by varying hydrogeologic conditions, moisture content and by geophysical anomalies in the subsurface (GPR and ERT data). Some of the scarps close to the alluvial plain of the river Rhine have been identified as erosional features. We opened six trenches perpendicular and parallel to the second topographic scarp and strand of the main RGBF in Ettlingen area. Trenching the main RGBF was precluded due to forest cover and the presence of big blocks of rock in the colluvium at the base of the slope (red Triassic sandstones). Trenches were up to 20 m in length and 2 m in width, and up to 3 m in depth. None of the trenches reached the Triassic Buntsandstein “basement”, and all exposed Pleistocene and Holocene strata. Some strata are interpreted as blocky/gravelly colluvium of the Glacial periods, Loess, redeposited gleyey Loess, soli-/gelifluction layers and deposits and organic paleosols. Most of these layers are clearly displaced by faults and downthrown to the west, although some strata appear to warp or fold over faults. Massive liquefaction and periglacial features have been found, the relation to the sedimentary sequences in the trenches need to be elaborated in future. The process is interpreted to be instantaneous, as massive colluvium is placed against clayey/silty Loess deposits, and therefore we attribute these displacements to earthquake-related faulting. Creep along the strand can be ruled out. The displacement on free faces is on the order of 30 – 50 cm per event vertically, and considerable horizontal offset (ca. 2 m), and we found evidence for two of such events. Applying the commonly used empirical relationships, these findings are interpreted as two events with a magnitude M larger than 6. These results show the bias between the seismogenic landforms (scarps, hanging valleys, triangular facets, etc.) in the eastern UGR margin and seismicity recorded by seismic stations in the area, as currently most of the activity is found in the southern URG near Freiburg. Our findings contribute significantly to the completeness of the earthquake history in the eastern central URG.
Interactions and feedbacks between water availability and domestic consumption in São Paulo Metropolitan Area
Authors: Souza Felipe , Gesualdo Gabriela , Sivapalan Murugesu , Mendiondo Eduardo
Published: March 2020

Water supply in large cities has challenged governments and water authorities because of the complexity involved in meeting water demands. The traditional challenges stem from the seasonality of precipitation and population growth. Although water resources management strategies assume potential scenarios for water demand growth to design water infrastructure, unexpected changes in the hydrological cycle may cause shocks to urban water supply systems and generate unanticipated patterns of consumption, such as occurred during the water crisis experienced by the São Paulo Metropolitan Area (SPMA) from 2014 to 2016. This work explores the coevolution of the coupled human-water system variables associated with the water supply system within the SPMA, from the late twentieth century to the present, to explain how water demand has influenced water availability, and vice-versa, in particular for the Cantareira Reservoir System. The challenges facing the human-water system in the region are of critical importance, given that it supplies water to more than 9 million people, and it supports economic activities that represent 12% of Brazil’s Gross Domestic Product. The analysis reveals that hydrological shifts are responsible for major structural transformations and they also have led to changes in domestic consumption. We conclude that modelling the interactions and feedbacks between water availability and consumption can provide more realistic storylines to implement strategies to address water scarcity than merely considering long-term demand scenarios, as it is normally done. In addition, policies implemented to promote water savings can have different responses at sub-regional scales and this can be explored also in the context of long-term scenarios.
Towards making karst hydrologic models more user-friendly – The integration of the LuKARS model into FREEWAT
Authors: Bittner Daniel , Rychlik Ayla , Klöffel Tobias , Leuteritz Anna , Disse Markus , Chiogna Gabriele
Published: March 2020

Modeling karst spring discharge while considering potential impacts of land use changes in a recharge area is a crucial task for water resource managers worldwide. Generally, such models are based on sophisticated mathematical functions developed and applied by researchers and their complex nature does not allow an intuitive applicability. To overcome this limitation and to make these models applicable for stakeholders, they need to be integrated in an applicable and open source framework that can be used by water managers without losing the original and full modeling functionalities.

In our work, we introduce a user-friendly modeling environment by integrating the recently proposed LuKARS (Land use change modeling in KARSt systems) model into FREEWAT (FREE and Open Source Software Tools for WATer Resource Management). LuKARS is a lumped, rainfall-discharge model for karst systems that considers impacts of land use changes by changing the area of a so-called hydrotope, representing a landscape unit with homogeneous soil and land use properties. FREEWAT provides an open source toolkit for water resource management that is implemented as a plugin in QGIS. The integration of LuKARS benefits from QGIS’ mapping, visualization and geospatial manipulation capabilities. The plugin of FREEWAT provides a modular concept of pre- and post-processing tools that facilitate the setup, calibration, analysis, storage and sharing of a LuKARS model.
Assessment of long-term stability of inductive conductivity sensors at Argo floats
Authors: Nezlin Nikolay , Halverson Mark , Leconte Jean-Michel , Shkvorets Igor , Siegel Eric , Zhang Rui , Johnson Greg
Published: March 2020

This study analyses accuracy and stability of salinity measurements collected by four Argo autonomous drifters with RBR Ltd. inductive conductivity sensors operating in the Pacific Ocean during the recent 2-4 years. Inductive sensors have advantages over traditionally used electrode-type cells due to their better resistance to surface contamination and low power requirements, resulting in more robust and accurate measurements and extended float lifetimes.  Proper assessment of the quality of the data collected by autonomous drifters is challenging due to lack of reference information. An important part of Argo program is the Delayed-Mode Quality Control process including salinity drift analysis and correction using the ‘Owens-Wong Calibration’ (OWC) method based on objective mapping of available reference data. This method, however, can misinterpret imperfect reference data as sensor drift. In this study, analyzing OWC output we introduce a combination of visualization methods focused on the locations where reference data can be treated as problematic. These methods include the analysis of spatial locations of the ‘profile correction factor’ along the float trajectory, comparing reference salinity fields calculated by the OWC method to additional reference sources (climatologies) and comparative analysis of different floats operating in the same area using the same reference datasets. The results demonstrate high level of stability of inductive conductivity cells on Argo floats, making them promising alternative for traditionally used Argo float CTDs equipped with electrode-type conductivity sensors.

 
Mechanisms of Extensional Strain Localization: An Example from Cordilleran Metamorphic Core Complexes
Authors: Levy Drew , Zuza Andrew
Published: March 2020

Crustal extension is a fundamental process in plate tectonics, and understanding its driving mechanisms is critical to our understanding the role of extensional deformation in the evolution of the Earth’s continents. How and why extension localizes into narrow belts versus being distributed across wide orogens remains enigmatic. Here we investigate extensional strain localization in the North American Cordillera (NAC) and Basin and Range province, where early phases of high magnitude strain (>100%) were fairly localized along a ~2500-km long belt of metamorphic core complexes, and subsequent late-stage low-magnitude strain appears to be fairly distributed across the 500-600-km width of the Great Basin. Various forces compete to drive intracontinental extension in the western United States, and we present field-based case studies of the Central NAC core complexes—the Ruby-East Humboldt, Snake Range, and Albion-Raft River-Grouse Creek—to explore strain localization due to plate-boundary stresses, internal body forces (GPE), and/or crustal rheology including thermal weakening from pervasive magmatism. The studied core complexes consist of significant syn-kinematic intrusions, and we demonstrate how the composition, volume and age (i.e., duration and relative timing) of these intrusions affected strain rates. Through a combination of new and synthesized U-Pb geochronology, 40Ar/39Ar thermochronology and electron backscatter diffraction (EBSD) analysis we link transient thermal and rheological evolution of the crust with deformation mechanisms from grain to outcrop to regional scales.  More broadly, we discuss the mechanisms and modes of crustal extension during orogenesis, and whether extension in active orogens is a transient response to modulate GPE gradients, or a precursor to orogenic collapse.
The Change of Aerodynamic Parameters over Beijing Urban Area during 1991-2018
Authors: Liu Xiaoman
Published: March 2020

       Higher and denser building groups are the most concentrated reflection of urbanization on the underlying surface reconstruction. With the continuous city expanding, urban wind field structure was changed, also the aerodynamic parameters dependent on. Based on observational data (slow-response) collected at 15 levels on Beijing 325m meteorological tower from 1991-2018, time and vertical trends of atmospheric stability, wind direction, wind speed, aerodynamic parameters were analyzed. Through Sen's slope, Mann-Kendall trend test and mutation analysis, we believe that urbanization has made a significant influence on local meteorological condition, and all the above variables mutated around the year of 1999. Before 1999, the proportion of neutral and unstable conditions declined with a trend of -0.63% and -2.0% per year respectively, and increased with a trend of +0.08% and +0.06% per year after 1999. As for wind direction, the dominant wind direction below 47m turned from southwest/northwest before 1999 to southeast after 1999, while above 47m remain unchanged as southeast, reflecting that the action range of urban impact is clearly distinguished from that of atmospheric background field. In terms of wind speed, the annual mean value trended to decrease at -0.0019m/s per year, and vertical wind speed trended to increased with height (per meter) at m/s per year, which reflected the continuous enhancement of attenuation effect of complex underlying on the near-ground wind speed. Furthermore, we found that although there was indeed a weaken tendency for wind speed in Beijing urban areas, but near neutral wind speed maintained a growth trend under 140m during 1999-2018. It was possible the deal with urban wake effect, wind field structure mutation or turbulence effect. Aerodynamic parameters  and d have undergone significant changes during the peak stage of urbanization, and tended to develop steadily with a 7-years fluctuations trend after that. In the past 28 years, d has increased from 1.34m in 1991 to 26.19m in 2018, while  has decreased from 2.75m to 1.02m. This is due to the fact that the increase of buildings average height is the result of roughness superposition. If the 7-year fluctuations trend continues, d of Beijing urban area will soon enter the next uplift period, during which the wind speed may increase slightly under nearly neutral conditions, and the cleaning effect on the pollution may be gradually enhanced.

 
Influence of Pacific meridional mode on ENSO evolution and predictability: asymmetric modulation and ocean preconditioning
Authors: Fan Hanjie , Huang Bohua , Yang Song
Published: March 2020

This study investigates the mechanisms for the Pacific meridional mode (PMM) to influence the development of an ENSO event and its seasonal predictability. To examine the relative importance of several factors that might modulate the efficiency of the PMM influence, we conduct a series of prediction experiments to selected ENSO events with different intensity from a long simulation of the Community Earth System Model (CESM). Using the same coupled model, each of the ensemble prediction is conducted from slightly different ocean initial states but under a common prescribed PMM surface heat flux forcing. In general, the matched PMM forcing to ENSO, i.e., a positive (negative) PMM prior to an El Niño (a La Niña), plays an enhancing role while a mismatched PMM forcing plays a damping role. For the matched PMM-ENSO events, the positive PMM exerts greater influence than its negative counterpart does, with stronger enhancement of positive PMM events on an El Niño than that of negative PMM events on a La Niña. This asymmetry in ENSO influence largely originates from the intensity asymmetry between the positive and negative PMM events in the tropics, which can be explained by the nonlinearity in the growth and equatorward propagation of the PMM-related SST and surface zonal wind anomalies through both wind-evaporation-SST (WES) feedback and summer deep convection (SDC) response. Furthermore, the response of ENSO to an imposed PMM forcing is modulated by the preconditioning of the upper ocean heat content, which provides the memory for the coupled low-frequency evolution in the tropical Pacific.
The effect of iron content on dehydration kinetics of talc
Authors: Yi Li , Zhang Ruixin , Yang Siyu
Published: March 2020

    Subduction zone is a distinct activity structure of hypocenter distribution of earthquakes. Hydrous minerals are involved in the chemical and physical activities in subduction zones. As a widely distributed hydrous mineral in shallow depths, talc has potential significance in various fault activities, and its dehydration reaction may be an important cause of the earthquake. Iron is a main element of the earth's crust, and the iron contents of hydrous minerals have a large impact on melting point, the rheological strength physical and chemical properties of the rocks. As a common hydrous mineral, the iron content of talc is not uniform; therefore, it is very important to study the dehydration kinetics of talc with different iron content.

    The dehydration reaction of three different iron contents talc was studied by means of synchronous thermal analysis, high temperature and high pressure differential thermal experiment and in-situ synchrotron X-ray diffraction experiment. Data of synchronous thermal analysis was calculated by Flynn-Wall-Ozawa (FWO). The activation energies of different iron content talc were calculated as 359.8 kJ/mol（FeO：0.4wt%），368.2.0 kJ/mol（FeO：2.0wt％），belonging to the second-order reaction. Data of in-situ synchrotron X-ray diffraction experiment was fitted by Avrami equation, E=350 kJ/mol（FeO：2.0wt％），n=1.67. The dehydration of talc followed random nucleation and growth mechanism. High content of iron obviously resulted in lower dehydration temperature.

  The release rate of talc dehydration fluid was 2.3E-05 to 6.1E-06 obtained by in-situ synchrotron X-ray diffraction experiment，it could lead to local overpressure induced rock brittle fracture. The supercritical fluid produced by the dehydration of talc in the subduction zone further attenuates the rock, resulting in local overpressure, which eventually leads to rock failure. The results suggested that the dehydration of different iron contents of talc may occur at the different depth around hundreds of kilometers, so the study was significant to our understanding of the genetic mechanism of earthquakes in the subduction zone.
Chemical composition and light absorption of brown carbon emitted from residential coal combustion in China
Authors: Song Jianzhong , Li Meiju , Fan Xingjun , Peng Peng'an
Published: March 2020

Brown carbon (BrC) is a type of light-absorbing organic compounds with a high capacity to absorb light in the low-wavelength visible and near-ultraviolet regions, which is ubiquitous in atmospheric aerosols, rainwater, and cloudwater samples. BrC can not only alter the light absorption and radiative forcing of aerosols but can also influence the formation of cloud condensation nuclei; therefore, it has a potential impact on atmospheric chemistry and climate change. Numerous studies have demonstrated that combustion processes are significant sources of atmospheric BrC, however most of these studies were focused on the emissions of biomass burning. Knowledge of primary BrC from coal combustion is still limited. In the study, smoke particles emitted from the combustion of residential coals with different geological maturity were collected in a combustion system. Then BrC fractions, including water soluble organic carbon (WSOC), water soluble humic-like substances (HULISw), alkaline soluble organic carbon (ASOC) and methanol soluble organic carbon (MSOC) were extracted and characterized for their abundances, chemical, and light absorption properties.

 

Our results showed that the abundance and light absorption of the coal combustion-derived BrC fractions were strongly dependent on the extraction methods used and the coal maturity. The abundances of MSOC fraction was significantly higher than WSOC and ASOC fractions and even higher than the sum of WSOC and ASOC, indicating that most organic compounds in smoke particles were soluble in pure methanol. The WSOC and MSOC fractions from the combustion of low maturity coal had relatively low SUVA254 and MAE365 values, indicated that they had relatively low levels of aromatic structures and light absorption.

 

The WSOC and MSOC fractions were characterized by ultrahigh-resolution mass spectrometry. The results showed that S-containing compounds (CHOS and CHONS) are found to be the dominant components of the WSOC, whereas CHO and CHON compounds make a great contribution to the MSOC samples. Noted that a greater abundance of S-containing compounds was found in the smoke produced from coal combustion compared to biomass burning and atmospheric samples, indicated that coal combustion could be an important source of atmospheric S-containing compounds in certain areas. The findings also suggest that organic molecules with a high aromaticity index and low polarity showed stronger light absorption. In summary, our study indicated that coal combustion is a potential source of atmospheric BrC and their abundance, chemical, and light absorption were strongly dependent on the extraction methods used and the coal maturity.
An improvement in accuracy and spatiotemporal continuity of the MODIS precipitable water vapor product based on a data fusion approach
Authors: Li Xueying , Long Di
Published: March 2020

Precipitable water vapor (PWV) is one of the key variables in the water and energy cycles, whereas current PWV products are subject to spatiotemporal discontinuity, low accuracy, and/or coarse resolution. Based on two widely used global PWV products, i.e., satellite-based MODIS and reanalysis-based ERA5 products, here we propose a data fusion approach to generate PWV maps of spatiotemporal continuity and high resolution (0.01°, daily) for the Upper Brahmaputra River (UBR, referred to as the Yarlung Zangbo River in China) basin in the Tibetan Plateau (TP) during the monsoon period (May‒September) from 2007‒2013. Results show that the fused PWV estimates have good agreement with ground-based PWV measurements from eight GPS stations (correlation coefficient = 0.87‒0.97, overall bias = -0.35‒1.78 mm, and root mean square error = 1.17‒2.04 mm), which greatly improve the accuracy of the MODIS PWV product. The high-resolution fused PWV maps provide detailed spatial variations which are generally consistent with those from the MODIS estimates under confident clear conditions and ERA5. During the monsoon period from 2007‒2013, monthly average PWV estimates across the UBR basin vary from ~6 to ~12 mm, and for each month high PWV values are found mainly along the UBR valley and at the basin outlet. The developed data fusion approach maximizes the potential of satellite and reanalysis-based PWV products for monitoring PWV and can be extended to other data available sources and study regions. The generated PWV estimates are highly valuable in understanding the water and energy cycles and retrieving atmospheric and surface variables for the south TP and its downstream areas.
Sediments of the Wala catchment and reservoir, Jordan: Geochemical analysis
Authors: Tarawneh Esraa , Bridge Jonathan , Macdonald Neil
Published: March 2020

This study reports data from field sampling of catchment and reservoir bed sediments undertaken in October 2013 in the Wala catchment, Jordan, and findings of geochemical analysis of the sediments. The primary aim of this study is to investigate the relationship between sediments from different locations within the catchment and those deposited within the reservoir. This is set within the overall context of an attempt to rationalise the use of modelling in a data-poor environment. Can targeted, limited acquisition of geochemical information within a logistically challenging environment add value to existing datasets in respect of ground truth for model predictions of sediment provenance within the catchment? Channel bed sediments were collected from sub-catchment outlets throughout the Wala catchment and shallow cores (c. 500 mm) extracted from three locations around the Wala reservoir. XRF and particle size analysis were performed on all samples and the data analysed in respect of mineralogical and pollutant geochemical signatures. Contrary to evidence from temperate lake studies, there was no strong record of discrete event-driven deposition at the Wala, likely due to reworking of sediments during high-flow recharge events following complete draw-down of the reservoir in the highly intermittent hydrological setting. Pollutant geochemistry shows variations consistent with patterns of land-use in the catchment, with levels of Pb, Co, Cu and Cr associated with urbanised regions in the north and west of the region. Sampled concentrations, particularly those of the reservoir sediments, are typically below thresholds for environmental health concern. However, combined with the modelled bias in flow and sediment inputs from this region (driven by asymmetric rainfall distribution), this emphasises a potential concern for future management of water quality and protection of groundwater during aquifer recharge.
Factors controlling the latent and sensible heat fluxes over Erhai Lake under different atmospheric surface layer stability conditions
Authors: Meng Xiaoni , Liu Huizhi
Published: March 2020

The stratification of atmospheric surface layer (ASL) plays an important role in regulating the water vapour and heat exchange across lake-air interface. Based on one-year data measured by Eddy Covariance (EC) technique over Erhai Lake in 2015, the ASL stability (ζ) was divided into six ranges, including unstable, weakly unstable, near-neutral(unstable side), near-neutral(stable side), weakly stable, and stable range. The characteristic of ASL stability conditions and factors controlling the latent (LE) and sensible (H) heat fluxes under different stability conditions were analyzed in this study. The stability conditions of Erhai Lake have noticeably seasonal and diurnal variation, which the near-neutral and (weakly)stable stratification usually occurred before July with frequency of 51.7% and 23.3%, respectively, but most of the (weakly)unstable stratification was observed since July with frequency of 59.8%. Large evaporation occurred even in stable atmospheric conditions, due to the coupled effects of relative larger lake-air vapor pressure difference and wind speed. The relative controls of LE and H by different atmospheric variables are largely dependent on the stability conditions. In stable and unstable range, LE is closely correlated with vapour pressure difference, whereas in weakly unstable to weakly stable range, LE is primarily controlled by wind speed. H is related to wind speed and lake-air temperature difference under stable conditions, but shows no obvious relationship under unstable conditions.
Development of drop freezing ice nucleation chamber (FINC), validation using lignin, and application to organic matter samples
Authors: Miller Anna , Brennan Killian , Wieder Jörg , Mignani Claudia , Zipori Assaf , Borduas-Dedekind Nadine
Published: March 2020

Aerosol-cloud interactions are a source of high uncertainties in predicting future climate. One important aerosol-cloud interaction is ice nucleation of supercooled liquid water droplets caused by ice nucleating particles (INPs). Predicting the distribution and concentration of INPs is a challenge because of their spatial and temporal heterogeneity in source, number, and composition. Organic aerosols are particularly diverse and complex in chemical and physical composition and can be highly ice active to varying degrees. Here we present the development of our drop Freezing Ice Nucleation Chamber (FINC) for the quantification of INP concentration of aerosol in the immersion freezing mode. As part of the development and validation of FINC, we show results from an intercomparison using lignin as a comparison standard with three other drop-freezing instruments (ETH’s Drop Freezing Ice Nucleation counter Zurich (DRINCZ), University of Basel’s LED-based Ice Nucleation Detection Apparatus (LINDA), and Weizmann Institute’s Supercooled Droplet Observation of Microarray (WISDOM)). In addition, we present here preliminary findings of FINC’s application for determining predictors of the ice nucleating ability of organic matter, using several standards and field-collected samples of dissolved organic matter as a proxy for organic aerosol emitted from natural waters. These methods and results can aid in the community’s search for predictors and parameterizations of organic aerosol induced ice nucleation.
Effect of vertical parameterization of a missing daytime source of HONO on concentrations of HONO, O3 and secondary organic aerosols in eastern China
Authors: Guo Yitian , An Junling , Zhang Jingwei , Qu Yu
Published: March 2020

Unexpectedly high daytime concentrations of nitrous acid (HONO) measured by field observations cannot be explained by theoretical calculations, implying that there may be a missing source of HONO in the daytime (Pmissing). The value of Pmissing near the ground (PGmissing) is different from that measured higher in the atmosphere (PHmissing) according to previous field studies, but the contribution of the vertical Pmissing profile in the atmospheric boundary layer (ABL) to air quality remains unknown. We derived a new formula PGmissing = 0.180 × J(NO2) [ppb s-1] based on field measurements near the ground, where J(NO2) is the photolysis frequency of NO2, and used the value of PHmissing inferred from Zeppelin measurements in the troposphere to parameterize Pmissing in the ABL. This parameterization was incorporated into the Weather Research and Forecasting model with Chemistry (WRF-Chem) to quantify the vertical effects of Pmissing on the concentrations of HONO, O3 and secondary organic aerosols (SOAs) in eastern China. Our results showed that PGmissing and PHmissing together further narrowed the gap between the simulations and observations, leading to a daytime increase in HONO concentrations of about 160 ppt near the ground compared with PGmissing only, an increase in the daytime concentrations of O3 of 8–37 ppb within the ABL in almost all of the studied domain in summer (1–19 ppb in winter and 4–21 ppb in autumn) and the largest hourly increase in the concentration of SOAs of 22.5 (18.6) μg m-3 in winter (summer). The results indicated that HONO sources near the ground have a limited effect on the HONO concentrations in the upper ABL even in summer in the presence of strong convective activities, while the HONO increase in the upper ABL can affect the concentration of HONO near the ground. When PGmissing was inserted into each model layer in the ABL, the concentrations of HONO higher in the atmosphere were substantially overestimated, suggesting that observations of the vertical distribution of HONO in the ABL are required in polluted areas.
Surface water resources assessment in Peru through SWAT hydrological model
Authors: Asurza Véliz Flavio Alexander , Traverso-Yucra Kevin Arnold , Lavado-Casimiro Waldo Sven , Felipe-Obando Oscar , Montesinos-Cáceres Cristian Albert , Llauca-Soto Harold Omar
Published: March 2020

Surface water resources in Peru show high spatio-temporal variability, being the prediction of streamflow at ungauged sites, one of the fundamental challenges today.  This research presents a methodology for regional parameter estimation at national scale using SWAT (Soil and Water Assessment Tools) model, with the goal of estimating the streamflow for three hydrographic regions in Peru: the Pacific, Titicaca and Amazonas. Hydrological models were calibrated using observed discharge data which is sparse and poorly distributed over Peru. In this context, we design a regional parameter estimation following the next steps: i) First, a regionalization of 3394 hydrological response units (HRU) in the whole country were built through Ward’s hierarchical cluster criterion, in which 14 calibration regions were defined. ii) A calibration procedure to obtain the best calibration parameters was made with Non-dominated Sorting Genetic Algorithm (NSGA-II) optimization using the Kling-Gupta (KGE) and Nash Sutcliffe Logarithmic (LogNSE) statistics. A total of 31 hydrological stations were selected to calibration and validation procedure with the condition of leaving at least one in each region defined at point i) iii) Using the physical similarity approach, each set of calibrated parameters was averaged in each region to get the regional parameter sets.

The Pacific drainage was grouped into 6 regions, in which the results of daily flows estimations showed a good performance (KGE varies between -0.89 and 0.79) with some exceptions in the central zone; and acceptable results in the low- flow estimation (logNSE varies between -1.66 and 0.82), whose performance declines in some stations in northern and southern areas. On the other hand, the Amazon and Titicaca drainages regions were grouped into 7 and 1 region respectively. The calibration in the Amazon resulted in a very good performance in the Andean part (KGE> 0.5 and LogNse> 0.3), however in the north (region shared with Ecuador), the results are moderately satisfactory (KGE varies 0.0 and 0.4). In the Titicaca region, very acceptable KGE calibration values ​​were obtained (KGE> 0.75, LogNSE> 0.6). This first stage of the research will allow evaluating the climate change impacts on the water resources availability in Peru.
Residual Mass Severity Index (RMSI) – a duration free method to characterise droughts
Authors: Afroz Rounak , Sharma Ashish , Johnson Fiona
Published: March 2020

The complexity of representing droughts has led to many drought indices being developed. A common aspect for many of these indices, however, is the need to adopt a predefined time period, over which a drought is characterized. Therefore, to declare a catchment as drought-impacted, 6, 12 or 24-month SPI are required. Actual water allocations, however, are required at all times and are thus duration free; a concept well described by the well-known residual mass curve. Here we propose a new framework to characterize drought, termed as the Residual Mass Severity Index (RMSI). As the name suggests, the RMSI defines drought based on the magnitude of the residual mass in any location which is calculated by performing a water balance using a prescribed demand. Demand here is adopted as the median monthly precipitation for the region. Water shortages only become significant when there is a sustained deficit compared to this demand. The above described residual mass is standardized to formulate the RMSI across Australia. The new RMSI has been validated against established drought indices (such as the SPI) to highlight the advantages of a duration-free drought index.

RMSI provides a simple method of assessing sustained and severe drought anomalies which is important with expected increases in water scarcity due to anthropogenic climate change. We demonstrate that RMSI can be used as a tool to evaluate the performance of General Circulation Models (GMCs) in representing the sustainability of water resource systems as a product of resilience, reliability, and vulnerability (RRV) of the system. Future projections of drought from GCMs which perform well in representing RMSI in the RRV context in the historical climate are then compared to drought projections from the full CMIP5 ensemble.

Keywords: Drought, Residual Mass Curve, SPI, RRV, Climate Change, CMIP5 GCMs
A classification and predictive model of the complex REE mineral system
Authors: Babaie Hassan , Davarpanah Armita
Published: March 2020

We model the intermittent, non-linear interactions and feedback loops of the complex rare earth elements (REE) mineral system applying the self-organized criticality concept.  Our semantic knowledge model (REE_MinSys ontology) represents dynamic primary and secondary processes that occur over a wide range of spatial and temporal scales and produce the emergent REE deposits and their geometry, tonnage, and grade. These include the scale-invariant, out-of-equilibrium geodynamic and magmatic processes that lead to the formation of orthomagmatic (carbonatite, alkaline igneous rocks) and syn- and post-magmatic hydrothermal REE deposits. The ontology also represents the redistribution of the REE from these primary ores by metamorphic fluids and/or post-depositional surface and supergene processes in sedimentary basins, fluvial channels, coast areas, and/or regolith around or above them. The ontology applies concepts of the complex systems theory to represent the spatial and spatio-temporal elements of the REE mineral system such as source, driver, threshold barriers, trigger, avalanche, conduit, relaxation, critical point attractor, and self-organization for the alkaline igneous, Iron oxide (subcategory of IOCG), hydrothermal, marine placers, alluvial placers (including paleo-placers), phosphorite, laterite, and ion-adsorption clays REE deposits. The ontology is instantiated with diverse data drawn from globally-distributed types of well-studied small to giant REE deposits to build the REE_MinSys knowledge base. Users can query the data in the knowledge base to extract explicit and inferred facts in each type of REE deposit, for example by asking: “Which rare earth elements are in REE phosphate deposits?”; “Which rare earth elements are largely explored in REE placer deposits?”  Data from the knowledge base will be divided into training and testing sets after they are preprocessed and trends and data patterns are identified through data analytical procedures. The training and test datasets will be used to build models applying machine learning algorithms to predict potential REE deposits of different kinds in unexposed or covered areas.
Seismic evidence for the subduction of North China Block to Yangtze Block beneath Tongbai-Dabie Orogenic belt
Authors: Zheng Hongwei
Published: March 2020

The Tongbai-Dabie Orogenic belt formed in the Middle-to-Late Triassic through a collision between the Yangtze Block (YB) and North China Block (NCB) and is a key component of the Central Orogen of China, which is famous on the most extensive high and ultrahigh pressure (HP/UHP) metamorphic zone in the world and marks the irregular suture between the YB and NCB. It is an ideal place to study the ancient orogenic processes between collided continents. In this study, we used a large number of P-wave arrival times recorded by portable and permanent seismic stations to reveal the structure of the crust and upper mantle beneath the Tongbai-Dabie orogenic belt and its adjacent region. Our images show the south-dipping high-velocity anomalies beneath the Tongbai-Dabie orogenic belt and the east-dipping high-velocity anomalies beneath the Tanlu Fault, which represent the southeastward subducted NCB in Mesozoic. While a huge high-velocity anomaly beneath the Wudang Moutin region extending down to 250 km is possible the ancient lithosphere of the Yangtze Craton remnant since the Paleoproterozoic. The northward subducted YB is only limited in the Eastern Dabie terrane and Yangtze foreland. Break-off retained Paleo-Tethyan oceanic slab are revealed at depths from the upper mantle 250 to 400 km. The structure of the crust and upper mantle suggests that the southeastward subduction of NCB resulted in the collision of NCB with YB.
Seasonal Evolution Features of Water Transport in the Lembeh strait of North Sulawesi
Authors: Zhang Junpeng , Pan Aijun , Kuang Fangfang , Jing Chunsheng , Hasanudin Muh , Kusmanto Edi , Sutisna Deny
Published: March 2020

A three-dimensional baroclinic nonlinear numerical model is employed to investigate the seasonal evolution features of water transport in the Lembeh Strait of north Sulawesi. In general, the direction of water flow in the strait is oriented northward with a maximum volume of about 4x10-3Sv in August. Interestingly, the volume transport will decrease to nearly zero from November to January. Water transport is mainly controlled by seasonally changed monsoon forcing. The large-scale ocean circulation nearby North Sulawesi is weaker during November-January and stronger from July to September. In addition, the source of water bypasses the Lembeh Strait in different seasons is diagnosed and testified by tracer-release experiments. It suggests that most of the water through the narrow channel is emanated from the southern off the Strait, not only the surface water, but also the deep water brought by the upwelling and the internal tides.