bluuebunny/crossref_metadata_2025 huggingface dataset:
The GPM Operational Radiometer Algorithm - Changes for 2021
Authors: Kummerow Christian , Brown Paula
Published: March 2020

The Global Precipitation Measurement (GPM) mission was launched in February 2014 as a joint mission between JAXA from Japan and NASA from the United States.  GPM carries a state of the art dual-frequency precipitation radar and a multi-channel passive microwave radiometer that acts not only to enhance the radar’s retrieval capability, but also as a reference for a constellation of existing satellites carrying passive microwave sensors.  In May of 2017, GPM released Version 5 of its precipitation products starting with GMI and continuing with the constellation of radiometers.  The precipitation products from these sensors are consistent by design and show relatively minor differences in the mean global sense.  Since this release, the Combined Algorithm hydrometeor profiles have shown good consistency with surface observations and computed brightness temperatures agree reasonably well with GMI observations in precipitating regions.  The same is true for MIRS profiles in non-precipitating regions.  Version 7 of the GPROF code will therefore make use of these operational products to construct it's a-priori databases.  This will allow continuous improvements in the a-priori database as these operational products are reprocessed with newer versions, while allowing the user community to better focus on the algorithm’s error covariance matrix and its validation.  Results from early versions of this algorithm will be presented.  In addition to creating an a-priori database that can be more directly updated with improvement to the raining and non-raining scenes, GPROF is also undertaking steps to improve the orographic representation of snow and a Neural Network based Convective/Stratiform classification of precipitation that will both help improve instantaneous correlations with in-situ observations.
Emissions and chemistry of volatile organic compounds (VOCs) in urban air: important contributions from oxygenated compounds
Authors: Yuan Bin , Wu Caihong , Wang Chaomin , Wang Sihang , Wang Wenjie , Qi Jipeng , Wang Baolin , Lou Shengrong , Wang Hongli , Song Wei , Wang Xinming , Hu Weiwei , Shao Min
Published: March 2020

Volatile organic compounds (VOCs) play central roles in formation of ozone and secondary particles. However, emissions and evolution of VOCs remain uncertain in different environments, including urban regions. A field campaign was conducted at an urban site of Guangzhou in September-November of 2018 to study ozone and particle pollution in this region. VOCs species were measured by both a gas chromatography mass spectrometer (GC-MS/FID) and a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). Another PTR-MS associated with comparative reactivity method (CRM) was used for quantifing OH reactivity in the atmosphere. In total, around 1700 ions were detected in mass spectra of PTR-TOF during this campaign, among of which 438 ions are with noticeable concentrations in the atmosphere. For all of the measured VOCs species, the total average concentrations of oxygenated VOCs was 28.2 ppb, which are significantly higher than other VOCs classes, namely alkanes (19.6 ppb), aromatics (4.4 ppb) and alkenes (2.9 ppb). These oxygenated VOCs contribute large fractions (campaign-average: 28%) of the total measured OH reactivity, which leaves only a small fraction of measured reactivity as “missing”. We will show that primary emission and secondary formation both contribute to the measured OVOCs. These results indicate important roles of OVOCs in emissions and evolution budget of VOCs in the atmosphere.
The potential significance of ericoid mycorrhizal fungi in ombrotrophic peatland biogeochemistry
Authors: Shao Siya , Roulet Nigel , Wu Jianghua
Published: March 2020

Northern peatlands have sequestered a huge amount of carbon through exceptionally low microbial activity which is partly attributed to their nutrient-poor conditions. Evergreen shrubs, a dominant species in ombrotrophic bogs, adapt to this nutrient-poor condition by developing organic nutrient acquisition strategies, mediated by ericoid mycorrhizal association. However, the mycorrhizal symbionts together with nutrient cycling have been omitted in peatland models, precluding our ability to simulate the significance of nutrient limitation in peatlands following environmental changes. To address this issue, we further developed the well-established peatland model MWM by incorporating a mechanistic mycorrhizal fungi model and both nitrogen and phosphorus cycles. The new model was adopted to simulate the fertilization effect on peatlands and evaluated against measurements from the long-term fertilization experiments at Mer Bleue, a raised ombrotrophic bog located in southern Ontario, Canada. The model successfully reproduced the observed dramatic changes with fertilization in mycorrhizal performance, vegetation composition and carbon cycle. Greater availability of inorganic nutrients diminished the role of mycorrhizal fungi in plant nutrient uptake. More assimilated carbon was allocated to shrub growth, which then inhibited the growth of sphagnum moss and ultimately posed a threat to the carbon-sequestration capacity of peatlands. Therefore, mycorrhizal activities, which have been overlooked in past peatland studies, could play a significant role in understanding how peatlands respond to increased nutrient deposition in the future.
Stellar Proton Events and Exoplanetary Habitability
Authors: Atri Dimitra
Published: March 2020

Superflares of energies up to 1038 ergs have been studied from Kepler and Gaia observations, and estimates of their energy and frequency on different types of stars is improving rapidly. Flares with energies up to 1035 ergs occur about once every 2000-3000 years on slow rotating stars like the Sun, but the occurrence rate is ∼ 100 times higher for younger, faster rotating stars of the same class. More than a dozen potentially habitable planets, like Proxima Centauri b and TRAPPIST-1 e, are in close-in configurations and their proximity to the host star makes them highly sensitive to stellar activity. Episodic events such as flares have the potential to cause severe damage to close-in planets, adversely impacting their habitability. Stellar Energetic Particles (SEPs) emanating from Stellar Proton Events (SPEs) cause atmospheric damage (erosion and photochemical changes), and produce secondary particles, which in turn results in enhanced radiation dosage on planetary surfaces. Taking particle spectra from 70 major solar events (observed between 1956 and 2012) as proxy, we use the GEANT4 Monte Carlo model to simulate SPE interactions with exoplanetary atmospheres. We have demonstrated that radiation dose varies significantly with charged particle spectra and an event of a given fluence can have a drastically different effect depending on the spectrum. Our results show that radiation dose can vary by about five orders of magnitude for a given fluence. In terms of shielding, we found that atmospheric depth is a major factor in determining radiation dose on the planetary surface. Radiation dose is reduced by three orders of magnitude corresponding to an increase in the atmospheric depth by an order of magnitude. We found that the planetary magnetic field is an important but a less significant factor compared to atmospheric depth. The dose is reduced by a factor of about thirty corresponding to an increase in the magnetospheric strength by an order of magnitude.
Citizen observers in hydrology – experiences from CrowdWater
Authors: Seibert Jan , Etter Simon , Strobl Barbara , van Meerveld Ilja
Published: March 2020

One possibility to overcome the lack of data in hydrology is to engage the public in hydrological observations. Citizen science projects are potentially useful to complement existing observation networks to obtain spatially distributed streamflow data. Projects, such as CrowdHydrology, have demonstrated that it is possible to engage the public in contributing hydrological observations. However, hydrological citizen science projects have, so far, been based on the use of different kinds of instruments or installations. For stream level observations, this is usually a staff gauge. While it may be relatively easy to install a staff gauge at a few river sites, the need for a physical installation makes it difficult to scale this type of citizen science approach to a large number of sites because these gauges cannot be installed everywhere or by everyone. Here, we present the CrowdWater smartphone app that allows the collection of hydrological data everywhere without any physical installation or specialized instruments. The approach is similar to geocaching, with the difference that instead of finding treasures, hydrological measurement sites can be set up by anyone at any location and these sites can be found by the initiator or other citizen scientists to take additional measurements at a later time. This way time series of observations can be collected. For stream levels, a virtual staff gauge approach is used: a picture of a staff gauge is digitally inserted into a photo of a stream bank or a bridge pillar, and the stream level during a subsequent field visit to that site is compared to the staff gauge on the first picture. For intermittent streams, soil moisture and plastic pollution, qualitative scales are used to enable citizens to report their observations. Participants have already contributed more than 10 000 observations. In this pico-presentation, we report on our experiences after about four years with the CrowdWater project and discuss the use of the app by citizen observers, methods to ensure data quality, and illustrate how these data can be used in hydrological model calibration.
Groundwater storage change in the Jinsha River basin from GRACE, hydrologic models, and in situ data
Authors: Chao Nengfang
Published: March 2020

Groundwater plays a major role in the hydrological processes driven by climate change and human activities, particularly in upper mountainous basins. The Jinsha River Basin (JRB) is the uppermost region of the Yangtze River and the largest hydropower production region in China. With the construction of artificial cascade reservoirs increasing in this region, the annual and seasonal flows are changing and affecting the water cycles. Here, we first infer the groundwater storage changes (GWSC), accounting for sediment transport in JRB, by combining the Gravity Recovery and Climate Experiment (GRACE) mission, hydrologic models and in situ data. The results indicate: (1) the average estimation of the GWSC trend, accounting for sediment transport in JRB, is 0.76±0.10 cm/year during the period 2003–2015, and the contribution of sediment transport accounts for 15%; (2) precipitation (P), evapotranspiration (ET), soil moisture change (SMC), GWSC and land water storage changes (LWSC) show clear seasonal cycles; the interannual trends of LWSC and GWSC increase, but P, runoff (R), surface water storage change (SWSC) and SMC decrease, and ET remains basically unchanged; (3) the main contributor to the increase in LWSC in JRB is GWSC, and the increased GWSC may be dominated by human activities, such as cascade damming, and climate variations (such as snow and glacier melt due to increased temperatures). This study can provide valuable information regarding JRB in China for understanding GWSC patterns and exploring their implications for regional water management.
Patterns in data of extreme droughts/floods and harvest grades derived from historical documents in eastern China during 801–1910
Authors: Hao Zhixin
Published: March 2020

In China, historical documents record a large quantity of information related to climate change and grain harvest. This information can help to explore the impacts of extreme drought or flood on crop production, which can provide implications for the adaptation of agriculture to higher-probability extreme climate in the context of global warming. In this paper, reported extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents were adopted in order to investigate the association between the reported frequency of extreme drought/flood in eastern China and reconstructed poor harvests during 801–1910. The results show that extreme droughts were reported more often in 801–870, 1031–1230, 1481–1530, and 1581–1650 over the whole of eastern China. On a regional scale, extreme droughts were reported more often in 1031–1100, 1441–1490, 1601–1650, and 1831–1880 in the North China Plain, 801–870, 1031–1120, 1161–1220, and 1471–1530 in Jianghuai, and 991–1040, 1091–1150, 1171–1230, 1411–1470, and 1481–1530 in Jiangnan. The grain harvest was reconstructed to be generally poor in 801–940, 1251–1650, and 1841–1910, but the reconstructed harvests were bumper in 951–1250 and 1651–1840, approximately. During the entire period from 801 to 1910, the frequency of reporting of extreme droughts in any subregion of eastern China was significantly associated over the long term with lower reconstructed harvests. The association between reported frequency of extreme floods and reconstructed low harvests appeared to be much weaker, while reconstructed harvest was much worse when extreme drought and extreme flood in different subregions were reported in the same year. The association between reconstructed poor harvests and reported frequency of regional extreme droughts was weak during the warm epoch of 920–1300 but strong during the cold epoch of 1310–1880, which could imply that a warm climate could weaken the impact of extreme drought on poor harvests; yet other historical factors may also contribute to these different patterns extracted from the two datasets.
Centennial to millennial-scale monsoon changes since the last deglaciation linked to solar activities and North Atlantic cooling
Authors: Liu Xingxing , Sun Youbin , Vandenberghe Jef , Cheng Peng , Zhang Xu , Gowan Evan , Lohmann Gerrit , An Zhisheng
Published: March 2020

Rapid monsoon changes since the last deglaciation remain poorly constrained due to the scarcity of geological archives. Here we present a high-resolution scanning X-ray fluorescence (XRF) analysis of a 13.5-m terrace succession on the western Chinese Loess Plateau (CLP) to infer rapid monsoon changes since the last deglaciation. Our results indicate that Rb/Sr and Zr/Rb are sensitive indicators of chemical weathering and wind sorting, respectively, which are further linked to the strength of the East Asia summer monsoon (EASM) and the East Asia winter monsoon (EAWM). During the last deglaciation, two cold intervals of the Heinrich event 1 and Younger Dryas were characterized by intensified winter monsoon and weakened summer monsoon. The EAWM gradually weakened since the beginning of the Holocene, while the EASM remained steady till 9.9 ka and then grew stronger. Both the EASM and EAWM intensity were relatively weak during the middle Holocene, indicate a mid-Holocene climatic optimum. Rb/Sr and Zr/Rb exhibit an anti-phase relationship between the summer and winter monsoon changes on centennial timescale during 16~1 ka BP. Comparison of these monsoon changes with solar activity and North Atlantic cooling events reveals that both factors can lead to abrupt changes on the centennial timescale in the early Holocene. During the late Holocene, North Atlantic cooling became the major forcing of centennial monsoon events.
Evaluation of dynamic properties and seismic performance of reinforced ground using renewable materials
Authors: Shin Seung Won , Ahn Seong Noh , Ryou Jae Eun , Jung Jongwon
Published: March 2020

The awareness of earthquakes increased due to the occurrence of two large scale earthquakes in Gyeongju (M 5.8) and Pohang (M 5.4) earthquakes in Korea. The development of structural design standards is required to reduce structural damage caused by earthquakes. Current seismic analysis for the structural design requires maximum ground acceleration due to earthquakes, which will be influenced by the dynamic properties of the ground. In this study, the dynamic properties of the ground were improved by mixing cement and biopolymer solutions with soils, which will affect the dynamic properties of soils. Thus, the resonant column tests were performed to estimate the improved dynamic properties of soils, and equivalent linear response analysis was conducted to explore the maximum ground acceleration on the ground. Based on the new maximum ground acceleration on the improved soils, the safety of geo-structure was estimated. The results show that the improved soil using cement and biopolymers results in the increased safety factor of the geo-structure.

Acknowledgement 

This work is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 20CTAP-C152100-02). Also, This research was supported by a grant(2018-MOIS31-009) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).

 
Assessment of the Regional Arctic System Model Intra-Annual Ensemble Predictions of Arctic Sea Ice
Authors: Maslowski Wieslaw , Lee Younjoo , Craig Anthony , Seefeldt Mark , Osinski Robert , Cassano John , Clement Kinney Jaclyn
Published: March 2020

The Regional Arctic System Model (RASM) has been developed and used to investigate the past to present evolution of the Arctic climate system and to address increasing demands for Arctic forecasts beyond synoptic time scales. RASM is a fully coupled ice-ocean-atmosphere-land hydrology model configured over the pan-Arctic domain with horizontal resolution of 50 km or 25 km for the atmosphere and land and 9.3 km or 2.4 km for the ocean and sea ice components. As a regional model, RASM requires boundary conditions along its lateral boundaries and in the upper atmosphere, which for simulations of the past to present are derived from global atmospheric reanalyses, such as the National Center for Environmental Predictions (NCEP) Coupled Forecast System version 2 and Reanalysis (CFSv2/CFSR). This dynamical downscaling approach allows comparison of RASM results with observations, in place and time, to diagnose and reduce model biases. This in turn allows a unique capability not available in global weather prediction and Earth system models to produce realistic and physically consistent initial conditions for prediction without data assimilation.

More recently, we have developed a new capability for an intra-annual (up to 6 months) ensemble prediction of the Arctic sea ice and climate using RASM forced with the routinely produced (every 6 hours) NCEP CFSv2 global 9-month forecasts. RASM intra-annual ensemble forecasts have been initialized on the 1st of each month starting in 2019 with forcing for each ensemble member derived from CSFv2 forecasts, 24-hr apart from the month preceding the initial forecast date.  Several key processes and feedbacks will be discussed with regard to their impact on model physics, the representation of initial state and ensemble prediction skill of Arctic sea ice variability at time scales from synoptic to decadal. The skill of RASM ensemble forecasts will be assessed against available satellite observations with reference to reanalysis as well as hindcast data using several metrics, including the standard deviation, root mean square difference, Taylor diagrams and integrated ice-edge error.
A comparative study of multi-scaled high-resolution seismic surveys in shallow marine environments: examples from three sites, offshore Korea
Authors: Kim Young Jun , Cheong Snons , Cukur Deniz , Yoo Dong-Geun
Published: March 2020

In marine seismic surveys, various acquisition systems are used depending on the survey purpose, target depth, survey environment, and conditions. A 3D survey of oil and/or gas exploration, for instance, require large-capacity air-gun arrays and six or more streamers with a minimum length of 6 km. In contrast, a high-resolution seismic survey for the shallow-water geological research and engineering needs a small capacity source such as air-gun, sparker, and boomer, deployed with a single-channel or multi-channel (24-channel) streamers. The main purpose of our seismic survey was to investigate the Quaternary geology and stratigraphy of offshore, Korea. Because the Quaternary is the most recent geological period, our target depth was very shallow at about 50 m below the sea-bottom. We used a high-frequency seismic source including a sparker of 2,000 J capacity or a 60 in3 mini GI-gun and an eight-channel streamer with a 3.125 m group interval or a single-channel streamer that included 96 elements. To compare the resolution of seismic data according to the seismic source, a boomer or sparker systems were used with the single-channel streamer on a small survey ship. The seismic data processing was performed at the Korea Institute of Geoscience and Mineral Resources (KIGAM) with ProMAX, and the data processing and resolution of each survey were compared based on their acquisition systems.
Improvement of evaluation of water age and submarine groundwater discharge: a case study in Daya Bay, China
Authors: Zhang Yan , Wang Xuejing , Li Hailong
Published: March 2020

The water age in coastal waters can be estimated by a simplified formula defined by activity ratio of radium isotopes when neglecting the effects of four factors including recirculated seawater (RSGD), open sea water end-member, sediments and rivers. Although this formula has been widely used, sometimes it is applied without checking the assumptions of neglecting the effects of the above-mentioned four factors. Here an attempt is made to give a generalized formula for estimating water age explicitly incorporating all the above-mentioned effects. The formula is then applied in Daya Bay, China by comprehensively using all the radium quartet (223,224,226,228Ra) data to assess the water age and submarine groundwater discharge (SGD). Data analyses indicate that the factors such as RSGD, open sea water end-member, sediments and rivers should be included in the general radium model when there are various radium sources and their contributions are unknown. It is found that in Daya Bay, neglecting the effects of RSGD underestimates the water age by 25.5-45.7% and neglecting the effects of open sea water end-member overestimates the water age by 120-130%. The SGD-derived fluxes of nutrients and trace elements are significantly higher than those from local rivers. SGD can support approximately 63-70% of the total primary production. Overall, this study emphasizes again the importance of the general radium model and enhances accuracy in estimating water age and SGD. Our results also reveal that SGD significantly influences coastal primary production in Daya Bay and other similar aquatic ecosystems.
Landscape and river self-organization limit the flux of fine particles
Authors: Phillips Colin , Rogéliz Carlos , Horton Daniel , Higgins Jonathan , Packman Aaron
Published: March 2020

Fine particles in rivers comprise a substantial fraction (>50%) of the mass leaving a landscape, while at shorter timescales they represent significant carriers of nutrients and contaminants with the potential to both degrade and enhance aquatic habitats. Predicting fine particle dynamics within rivers remains challenging due to a complex relationship between sediment and water availability from the landscape. This inherent complexity results in watershed-specific understandings of suspended sediment dynamics, typically parameterized as empirical functions of catchment land use, geology, and climate. However, observations of significant fine particle storage within river corridors may indicate that the flux of suspended sediment depends on reach-scale hydraulics. To better understand these dynamics, we synthesized over 40 years of suspended sediment concentration (SSC), hydraulic geometry, river flow, and grainsize data collected by the US Geological Survey from hundreds of rivers spanning a large variety of environments across the continental United States. This data synthesis reveals a strong nonlinear trend between reach-scale hydraulics and the suspended sediment flux, with a secondary dependence on particle properties. The multi-site synthesis reveals that by normalizing the suspended sediment flux by the bankfull shear stress and flux results in a collapse of the observed data onto a single function that describes a self-organizing structure for suspended sediment transport in watersheds. This general relationship indicates strong support for the role of autogenic processes in setting the flux of fine particles and erosion rates of watersheds.
A new weighted MSE loss for wind speed forecasting based on deep learning models
Authors: Chen Xi , Yu Ruyi , Ullah Sajid , Wu Dianming , Liu Min , Huang Yonggui , Gao Hongkai , Jiang Jie , Nie Ning
Published: March 2020

Wind speed forecasting is very important for a lot of real-life applications, especially for controlling and monitoring of wind power plants. Owing to the non-linearity of wind speed time series, it is hard to improve the accuracy of runoff forecasting, especially several days ahead. In order to improve the forecasting performance, many forecasting models have been proposed. Recently, deep learning models have been paid great attention, since they excel the conventional machine learning models. The majority of existing deep learning models take the mean squared error (MSE) loss as the loss function for forecasting. MSE loss is linear. Consequently, it hinders further improvement of forecasting performance over nonlinear wind speed time series data.   
 
In this work, we propose a new weighted MSE loss function for wind speed forecasting based on deep learning. As is well known, the training procedure is dominated by easy-training samples in applications. The domination will cause the ineffectiveness and inefficiency of computation. In the new weighted MSE loss function, loss weights of samples can be automatically reduced, according to the contribution of easy-training samples. Thus, the total loss mainly focuses on hard-training samples. To verify the new loss function, Recurrent Neural Network (RNN), Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) have been used as base models. 
 
A number of experiments have been carried out by using open wind speed time series data collected from China and Unites states to demonstrate the effectiveness of the new loss function with three popular models. The performances of the models have been evaluated through the statistical error measures, such as Mean Absolute Error (MAE). MAE of the proposed weighted MSE loss are at most 55% lower than traditional MSE loss. The experimental results indicate that the new weighted loss function can outperform the popular MSE loss function in wind speed forecasting. 
Spatial Prediction and Hazard Assessment Models of Hillslope Debris Flows at Village-Side Hillslope in Eastern Taiwan
Authors: Chen Tien-Chien , Cheng Chun-Yang , Su Chunya , Yin* Hsiao Yuan
Published: March 2020

This study develops the spatial prediction and hazard assessment models of hillslope type debris flow (HDF) to enhance the prevention and early warning of the HDF disaster to the villages. Induced by serious earthquakes and extreme weather conditions, HDF occurred frequently on the villages-side slopeland in Eastern Taiwan. The small scale HDF are often prone into high damage, because those slopeland is adjacent to the village. Based on this, to develop the spatial prediction and hazard assessment models of HDF is improving the safety of the residents.

This study uses the slope unit concept to establish the proper topographic unit for the spatial analysis. Fisher’s discriminant method is applied to develop the HDF spatial prediction model which consisted in 7 factors achieved from the slope units of metamorphic geology area in Eastern Taiwan. 27 HDF and 27 landslide events were adopted to develop the spatial prediction model, the model as following:

y=-1.144X1-0.993X2-0.049X3+0.622X4+0.353X5+0.57X6+0.478X7

In above equation, y is the discriminant function, X1 is the Average width of watershed, X2 is the Average gradient of the initiation region, X3 is the form factor of the initiation region, X4 is average width of the initiation region, X5 is the Depression ratio of the initiation segment1, X6 is the depression ratio of the transport segment DRT, X7 is the Gradient ratio of the initiation region. If the discriminant function y is greater than 0, a HDF is identified, otherwise a shallow landslide slope is identified. The results showed the overall correct estimation ratio is 88.2% and 85% verification ratio have been achieved in this study. 

The prediction model was then applied to 8 villages in study area, and the results show that 15 HDF have been caught in a total of 19 HDF in 8 village. The capture rate is about 79% and the overall capture rate of HDF and landslide unit is also 85%. In overall, the results show a good applicability of the prediction model in the metamorphic rock.

The project further draw up the hazard assessment model and comparing the result to the real HDF events which investigated by the field survey in 8 villages. Results showed that the potential of real HDF events were mostly classified in medium and high potential levels. Among them, there are 15 HDFs classified in medium and high potential in 19 HDFs. Concluding the results of the potential analysis, the result show a good application tendency in this research.
Development of Web GIS based Surface Soil Erosion Prediction System
Authors: Lee Dongjun , Yang Jae E , Lim Kyoung Jae , Kim Jonggun , Jang Won Seok
Published: March 2020

This study is to develop the Web GIS-based surface soil erosion prediction system that informs soil information such as daily potential soil erosion, soil quality, and best management practices (BMPs). The system involves three functions that are: 1) to predict daily potential soil erosion in the study areas (e.g., Jaun-Cheon, Bukhan-Gang, Namhan-Gang, and Gyoungan-Cheon); 2) to provide the current levels of soil qualities at field scale; 3) to recommend BMPs which can improve soil qualities. This study developed a module based on MUSLE and assessed the availability of the module comparing with the measured data at sample fields (3%, 9% slope). After verification of the module, the Web GIS-based system was developed using a user-friendly interface. The users can obtain the visualized soil erosion information through the interface and compare the amount of soil erosion using the single field or multi-fields analysis tool developed in this study. Moreover, the users can find the current level of soil qualities at fields they selected and gain various applicable BMPs information. The system enables to inform non-experts to soil information without using a complex model and equation. Therefore, the system can play a significant role in recognizing the importance of soil resources and enacting laws relative to soil conservation.
Girls on Ice Switzerland – using immersion to inspire interest in science
Authors: Naegeli Kathrin , Bouscary Chloé , Coch Caroline , Fridrich Anja , Gugerli Rebecca , Habermann Marijke , Hellmann Lena , Kronenberg Marlene , Langhammer Lisbeth , Mollaret Coline , Schaub Yvonne , Schwikowski Margit , Wee Julie , Wenner Michaela
Published: March 2020

Girls on Ice Switzerland runs tuition-free wilderness science expeditions for young women from diverse backgrounds. The glacier expeditions interweave science (e.g. glaciology, geomorphology, environmental aspects), art and mountaineering. Girls on Ice Switzerland does not only intend to transfer scientific knowledge, but also aims on a general understanding of the scientific process, on a mediation of nature experiences and on an enhanced self-confidence and self-evaluation. A combination of inquire-based teaching, experiential learning, and the tangibility of climate change science in the alpine environment provide a unique teaching environment. This particular framework allows to communicate science to non- and potential not-yet-peers, to facilitate insights into the scientific work through hands-on experiences, and to enhance the participants’ general interest in science.

Between 2017 and 2019, Girls on Ice Switzerland organised four glacier expeditions, which were evaluated in detail by pre- and post-inquiry of the participants. Through both quantitative and qualitative methods, the evaluation focused on the (i) perception of science, (ii) scientific knowledge, (iii) critical thinking, (iv) interest in science, (v) self-assessment and self-efficiency and (vi) connection to nature. It showed that the programme overall reached its initially set aims and that it particularly fosters critical thinking, increases physical and intellectual self-confidence and strengthens confidence in women.

Here, we will present the programme Girls on Ice Switzerland, its link to Inspiring Girls Expeditions and the overall philosophy, but also highlight evaluation results that help to optimize the science communication by demanding a clear set of goals for different characteristics of the programme. The unique women-only environment is ideal to encourage young women to start studies within the field of natural sciences and strengthen young female scientists to pursue their academic career.
A large eddy simulation study of the inshore nutrient uplift process: The role of topography
Authors: Wang Zheye , Li Shuang
Published: March 2020

Artificial fish reefs are the underwater structures placed on the ocean floor to simulate some characteristics of natural reefs. The onshore current can be transformed into upwelling under the influence of artificial fish reefs, thus the nutrient at the bottom of the near shore can be raised, which increases the prey of plankton and fish yield. In order to investigate this phenomenon, a 3D large eddy simulation (LES) of the ocean boundary layer was combined with four different types of artificial fish reef terrains (square, convex-fan, isosceles right triangle, concave-fan). In the near surface, almost only the square terrain can uplift the nutrient, which brings about the most uniform nutrient distribution. Based on the size of integral values of nutrient concentration in the upper part of the four reefs, they are listed as follows: square terrain, convex-fan terrain, isosceles right triangle terrain, concave-fan terrain decreases (from largest to smallest). What is more, the integral values of the four terrains reduce exponentially. Because the nutrient flow encounters the square terrain’s vertical plane, it has a larger vertical velocity. Nevertheless, for convex-fan terrain and isosceles right triangle terrain, their slopes are smoothly, resulting in poor lifting effect. Meanwhile, compared with the other three types of terrains, the concave-fan terrain can prevent the overflow of nutrients better. Among those four reefs, it can be found the square-shaped artificial fish reef is the best one for uplifting the nutrient.
GRACE-FO and Swarm integrated data analysis reveals ionospheric disturbances on the accelerometer measurements
Authors: Tzamali Myrto , Peidou Athina , Pagiatakis Spiros
Published: March 2020

Low Earth Orbit (LEO) satellites are subject to numerous disturbances related to the Earth’s upper ionosphere. Perturbations induced by the activity of the electromagnetic field (EM) at the upper ionospheric layers have not been fully understood yet. This study focuses on the disturbances shown on GRACE-FO accelerometer measurements when the EM field was disturbed by an intense geomagnetic storm occurred on August 2018. A thorough analysis of the accelerometer measurements of GRACE-C as well as the magnetic and electric field measurements from Swarm constellation is conducted, to enlighten their impulse-response relationship. We derive the temporal variations of the magnetic field by removing the main static field and we calculate the Poynting vector employing the Swarm magnetic field measurements and electric field data, by implementing rigorous data analyses to analyze the spatiotemporal characteristics of the energy flow of the electromagnetic field. Results show that GRACE-C accelerometer measurements are highly disturbed in the higher latitudes especially near the auroral regions. The signature of the spatial temporal variations of the magnetic field and the Poynting vector demonstrates very similar behaviour with GRACE-C disturbances. Cross wavelet analysis between Poynting vector and GRACE-C accelerometer disturbances shows a very strong coherence. With the two LEO missions, i.e. GRACE-FO and Swarm, orbiting the Earth in very similar orbits, further analysis towards integrating their measurements will enhance our understanding of the interaction of LEO satellites with the space environment and how this interaction is depicted in their measurements.
Isotopic Insights into Methane Production and Emission in Diverse Amazonian Peatlands
Authors: Hoyt Alison , Cadillo-Quiroz Hinsby , Xu Xiaomei , Torn Margaret , Bazán Pacaya Arturo , Jacobs Marie , Shapiama Peña Rony , Ramirez Navarro Diego , Urquiza-Muñoz David , Trumbore Susan
Published: March 2020

Tropical peatlands have the potential to be significant sources of methane (CH4) to the atmosphere but their contribution to the global methane budget remains uncertain. Although much prior work has focused in Southeast Asia, other tropical regions, such as the Congo and the Amazon, have a much wider diversity of peatlands with more variable CH4 emissions. Our work aims to better understand CH4 production and emissions in these diverse peatlands, and how they are controlled by hydrology, geochemistry and vegetation. Using stable isotope and radiocarbon measurements, we assess the production pathway for methanogenesis and its carbon source at sites across the Pastaza-Marañon basin in Peru. As the largest peatland complex in the Amazon, this region is home to many peatland types, from palm swamps to open peatlands to pole forests. We find clear links between site geochemistry, hydrology, and CH4 production. In rain-fed ombrotrophic sites (pH 3-4), we observe low emissions and highly depleted δ13CH4 values (as low as -100‰). The lack of external nutrients and acidic conditions likely limit methanogenesis, and hydrogenotrophic methanogenesis dominates. In more minerotrophic sites (pH 5-6), more enriched methane (-75 to -60‰) suggests a contribution from acetoclastic methanogenesis. Emissions rates are also higher, likely fueled by external nutrient inputs from seasonal flooding. Across sites, modern, vegetation-derived inputs are the dominant carbon source for methanogenesis, with a limited contribution from old peat carbon in some ombrotrophic sites. The strong relationships we observe between peatland hydrology, vegetation, geochemistry and methane emissions will enable future work to upscale methane emissions across the region.
Bedrock Topographic Evolution from Rockfall Erosion
Authors: Beer Alexander R. , Ulizio Thomas P. , Ma Zewei , Fischer Jade , Lamb Michael P.
Published: March 2020

Gravity moves dry grains or blocks downhill in rockslides and rockfall. These mass movements can cause large boulders to saltate and impact with huge energies. Boulder impacts into bedrock surfaces should cause significant bedrock erosion, likely shaping the topography even in the absence of water.  Examples of potential rockfall-driven bedrock landforms include bedrock gullies on steep hillslopes, so-called plinth surfaces on caprock-topped mesa escarpments, and steep impact-crater slopes on planetary surfaces. Although grain impact processes have been incorporated into mechanistic models for fluvial and debris-flow incision, similar models for dry rockfall erosion have yet to be developed.

To explore the potential for dry rockfall to erode bedrock and shape the topography, we set up a discrete, cellular D16 dry grain saltation trajectory model accounting for particle saltation dynamics and evolving topography. We calibrated the model variables (i.e., particle hop angles, distances and velocities) for different grain sizes and hillslope angles using laboratory experiments of dry gravel transport over a tilted foam bed that served as an erodible bedrock analogue. We then explored the calibrated model for a broad range of hillslope angles, grain sizes and bedrock erodibilities.

Both model and experiments predict significant erosion due to rockfall-driven impacts. As the topography develops, alcoves (shell-shaped hollows) form near the upslope end of the model domain. These alcoves eventually overdeepen and fill with talus, preventing further erosion. Farther downslope, topographic feedbacks drive rockfall into incipient channels, which cause those channels to incise resulting in gullies. Overall, our work suggests that dry rockfall can be a significant bedrock incision process, and can lead to gully formation, even for hillslope angles that are significantly less than the angle of repose.
Along-Strike Variation of Halokinesis and Structural Inheritance Along the West African Salt Basin, South Atlantic
Authors: Legeay Etienne , Ringenbach Jean-Claude , Callot Jean-Paul
Published: March 2020

Along the West African margin from Gabon to southern Angola, the Loeme Aptian salt deposited during the late rift break-up process. Following the Atlantic opening, passive margin subsidence, large deltas and dynamic topography triggered and shape gravity tectonic systems. Evaporite deposition occurred during the break-up process, from the rupture of the continental crust to the spreading, thus providing an early inheritance (in term of thickness and geographic distribution of evaporites) for future salt tectonics, which is largely controlled by the genetic domain compartmentalizing the margin, namely the proximal margin, the neck basin, the distal margin, and the outer high and exhumed mantle. Classically, since the mid-90s the gravity gliding system pattern, with the usual triptych extension-translation-compression, has been over-applied along the West African margin. Recent data from Angola show mini-basins in a context of gravity spreading in addition to pure gliding-spreading roll-overs, rafts and diapirs, as well as mini basins developed during the early phase of evolution, and were later on squeezed by the gliding cell. We present here a regional study to compare major internal and external factors controlling halokinesis structural styles and we propose new maps and cross-sections up to 300 km long from onshore to ultra-deep offshore, to describe the main domains and styles across the Gabon, Lower Congo, Kwanza, Benguela and Namibe sub-basins. This work is based on an extensive 2D and 3D seismic reflection data, wells and internal reports. Margin scale cartographic compilation of both pre- and post-salt tectono-sedimentary trends provide elements to constrain both geometries and kinematics. This study documents the spatial and temporal distribution of both the inherited salt controlled basins (i.e. minibasins, salt ridges, etc.) as well as the superimposed gravitational systems, their characteristics and drivers (e.g. gliding, spreading), and by linking them to the genetic domains of the margin to highlight their various roles.
Will human impacts on Alpine geomorphic processes scale up to the depositional record?
Authors: Lane Stuart
Published: March 2020

The Anthropocene is widely described as producing a rupture in the global stratigraphic signature, attributable to human activities. There is no doubt that human activities have introduced new products into the stratigraphic record; and that humans are modifying the geomorphic processes that produce the sediment which then becomes incorporated into that record. The stratigraphic literature is replete with simplistic generalisations of how sediment flux to the continental shelf is changing, such as increasing due to soil erosion or decreasing due to hydropower related sediment flux disconnection. Here we argue that human impacts on geomorphic processes in the Anthropocene are unlikely to be stationary for long enough for them to be seen consistently across the depositional record of many different environments. Illustrating this for a major inner-Alpine drainage basin, the Swiss Rhône, we show that human-driven global climate-change is indeed dramatically altering the geomorphic process regimes of Alpine environments. However, there are three broad reasons why this is unlikely to be seen in the future geological record. First, the geomorphic response that drives increased sediment delivery is transient because of the significant regime changes associated with global climate change impacts. Second, such increases are countered by other human impacts, notably those on sediment flux, which are tending to reduce the connectivity of sediment sources to downstream sediment sinks. Third, human impacts on both sediment sources and connectivity are nonstationary, driven by both exogenous factors (here illustrated by the worldwide economic shock of 2008) and endogenous ones, notably human response to the perceived problems caused by both sediment starvation and sediment over-supply. In geomorphic terms, then, there is a difference between the pervasive nature of Earth system shifts that we see in the pre-Holocene depositional record and the more ephemeral impacts of the Earth system – human coupling associated with the Anthropocene. The extent to which this is the case is likely to vary geographically and temporally as a function of the degree and nature of human impacts on geomorphic processes. Thus, the primary challenge for future prediction will be as much the prediction of the complex and reflexive nature of human response as it will be geomorphic processes themselves.
Vertical profile of suspended sediment concentration in the turbidity maximum zone of the partially stratified Changjiang Estuary
Authors: Li Zhanhai
Published: March 2020

In order to study the vertical profile of suspended sediment concentration (SSC) and its temporal variation in the partially stratified estuaries, the profile of SSC, as well as the profiles of current and salinity were measured over a neap-spring cycle for 16 tidal cycles in April 2012 in the turbidity maximum zone (TMZ) of the North Passage in the Changjiang Estuary. The observations revealed that the TMZ was characterized by high SSCs, strong current velocities and remarkable saltwater intrusion. Both salinity and SSCs could yield strong density stratification which would exert important influence on the shape of SSC profile by damping sediment diffusion. The vertical profiles of SSCs mainly exhibited three typical types, i.e., two-layer structure profile, exponential profile and linear profile, and had significant flood-ebb and neap-spring variation patterns. In a tidal cycle, the two-layer structure profile mainly occurred during the strong stratification periods, and the exponential and linear profiles mainly occurred in the weak stratification periods. About 60% observed SSC profiles belonged to the two-layer structure profile, and 40% observed SSC profiles belonged to the exponential and linear profiles. The formation of the two-layer structure profiles during the latter half of floods and early half of ebbs was attributed to the bottom lateral currents, because it could drive the higher SSC and higher salinity in the deep channel to the south shoal through the bottom water layer. Two new empirical equations for the SSC profiles are proposed. They can predict the linear and exponential profiles accurately, and predict the two-layer structure profile reasonably. Both the exponential and linear SSC profiles had constant diffusion coefficient in the water column, and they can be delineated by a unified equation. Additionally, the bottom lateral currents directed to the south flank during 87% of the survey period, and could enhance the SSC, salinity and water exchanges between the channel and the shoal.