bluuebunny/crossref_metadata_2025 huggingface dataset:
Cautions blasting in vicinity of underground laboratories
Authors: Szumny Marcin , Fuławka Krzysztof , Mertuszka Piotr
Published: March 2020

Development of the new mining technologies is inherently connected with scientific researches. In many cases, there must be done in very specific and demanding conditions what is possible in underground laboratories only. These facilities can be located in tunnels or chambers deep below the surface. In this kind of underground objects very specific and sophisticated scientific devices are often used. Modern technical equipment is frequently very sensitive and must be protected from various undesirable factors e.g. vibrations. During the lifetime of some underground facilities, located in the hard rocks there  could be the necessity to perform works where explosives have to be applied. One of the unwanted effects of explosives usage in rock is generation of the seismic waves.Vibrations inducted by seismic wavescan generate additional seismic load on the support of the underground facility and damage sensitive scientific devices. In this kind of blasting works, called caution blasting, there are strict restrictions for maximum vibration level that cannot be exceeded. In these kind of situations there must be used explosives and technologies that ensure fulfilling these kinds demands and restrictions. In this paper, prepared in the framework of in The Baltic Sea Underground Innovation Network (BSUIN) project, there are shown some solutions that could be applied during blasting works perform in the vicinity of protected facilities.
Forecasting North America Winter Surface Air Temperature Using Machine Learning Methods
Authors: Qian Qifeng , Jia Xiaojing , Lin Hai
Published: March 2020

Two machine learning (ML) models (Support Vector Regression and Extreme Gradient Boosting; SVR and XGBoost hereafter) have been developed to perform seasonal forecast for the winter (December–January–February, DJF) surface air temperature (SAT) in North America (NA) in this study. The seasonal forecast skills of the two ML models are evaluated in a cross-validated fashion. Forecast results from one Linear Regression (LR and hereafter) model and two Canadian dynamic climate models are used for the purpose of a comparison. In the take-one-out hindcast experiment, the two ML models and the LR model show reasonable seasonal forecast skills for the winter SAT in NA. Comparing to the two Canadian dynamic models, the two ML models and the LR model have better forecast skill for the winter SAT over the central NA which mainly get contribution of a skillful forecast of the second Empirical Orthogonal Function (EOF) mode of winter SAT over NA. In general, the SVR model and XGBoost model hindcasts show better forecast performances than LR model. However, the LR model shows less dependence on the size of the training dataset than SVR and XGBoost models. In the real forecast experiments during the period 2011-2017, compared to the two Canadian dynamic climate models, the two ML models clearly improve the forecast skill of winter SAT over northern and central NA. The results of this study suggest that ML models may provide real-time supplementary forecast tools to improve the forecast skill and may operationally facilitate the seasonal forecast of the winter climate of NA. 
A new coupled modeling system developed for Arctic sea ice simulation and prediction
Authors: Yang Chao-Yuan , Liu Jiping , Xu Shiming
Published: March 2020

Arctic sea ice has experienced dramatic changes for the past few decades. Recent changes in the properties of Arctic sea ice have posed significant challenges to the research community to provide sea ice predictions. To improve our capability to predict Arctic sea ice and climate, we have developed a coupled atmosphere-sea ice-ocean model configured for the Arctic with sufficient flexibility. The Los Alamos sea ice model is coupled with the Weather Research and Forecasting (WRF) Model and the Regional Ocean Modeling System (ROMS) within the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system. A series of sensitivity experiments with different physics options have been performed to determine the ‘optimal’ physics configuration that provides reasonable simulation of Arctic sea ice.

It is well known that dynamic models used to predict Arctic sea ice at short-term periods strongly depend on model initial conditions. Thus, a data assimilation that integrates sea ice observations to generate realistic and skillful model initialization is needed to improve predictive skill of Arctic sea ice. Parallel Data Assimilation Framework has been implemented into the new modeling system to assimilate SSMIS sea ice concentration, and CyroSat-2 and SMOS sea ice thickness using a localized error subspace transform ensemble Kalman filter (LESTKF). We have conducted Arctic sea ice predictions for the melting seasons of 2017 and 2018. Predictions with improved initial sea ice states show reasonably accurate sea ice evolution and small biases in the minimum sea ice extent.

Storms-induced ocean surface waves are capable of breaking pack ice into smaller floes and changing the sea ice melting rate. We have also coupled the Simulating Wave Nearshore (SWAN) with above atmosphere-sea ice-ocean coupled system and examined the impacts of wave-ice interactions on sea ice simulation. Preliminary results suggest ocean waves have direct and indirect impacts on sea ice. Direct impacts are the fracturing of ice pack and indirect impacts the change of ocean thermo-structure through the wave breaking.
Effects of litter manipulation on soil biochemical processes: A global meta-analysis
Authors: He Keyi , Feng Jiguang , Zhu Biao
Published: March 2020

Global changes can alter the quantity and quality of above-and below-ground inputs, which will affect soil carbon (C) dynamics and nutrient cycles. The effects of detritus from above- and below-ground are not entirely uniform. Although numerous experiments have been conducted, the general patterns of how litter manipulation affect soil biochemical processes and whether such effects varied among changes in above- and below-ground inputs remain unclear.

Here, we conducted a meta-analysis of 2181 observations from 216 published studies to examine the responses of belowground processes to manipulated above- and below-ground litter alterations.Our results showed that, across all studies, litter manipulation generally had significant effects on soil moisture, but had minor effects on soil temperature and pH. Litter addition generally stimulated C and nutrient cycle, and microbial variables, whereas removal of litter, root and both of them generally suppressed or did not change these processes. Specifically, litter addition significantly increased soil respiration (Rs) and soil organic carbon (SOC) content in the mineral soil by 24.5% and 6.2%, respectively. Litter removal, root removal, and no inputs (removal of both litter and root) reduced Rs by 23.6%, 38.1%, and 50.2%, respectively. Litter removal and no inputs on average decreased SOC content in the mineral soil by 19% and 22.8%, respectively, but such negative effect did not occur under root removal. This suggests that aboveground litter may be more valid in soil C stabilization than roots within a relatively short period. In addition, manipulation level also regulated the responses of SOC, Rs and MBC to litter alterations. The direction of litter manipulation effects on multiple variables are basically similar among ecosystem types.

Overall, our findings provide a reference for assessing the impact of primary productivity growth on C and nutrient cycling in terrestrial ecosystems under global changes, and highlight that the effects of aboveground litters and roots should be separately incorporated into soil C models.
Transpolar arcs under a long-duration radial IMF interval: A case study
Authors: Park Jong-Sun , Shi Quan Qi , Nowada Motoharu , Shue Jih-Hong , Kim Khan-Hyuk , Lee Dong-Hun , Zong Qiu-Gang , Degeling Alexander W. , Tian An Min , Pitkänen Timo , Zhang Yongliang , Rae I. Jonathan , Bai Shichen , Yao Shutao
Published: March 2020

Although the responses of the transpolar arcs (TPAs) to the north-south or dawn-dusk interplanetary magnetic field (IMF) orientations are relatively well known, the effects of the Sun-Earth IMF component on the TPA formation are still poorly understood. On 29 October 2005, the IMF pointed nearly earthward over seven hours from 08:20 to 15:40 UT. In this time interval, the Defense Meteorological Satellite Program (DMSP) satellite and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite observed two clear TPA structures (one near the magnetic pole and the other near the dawnside auroral oval) in the northern hemisphere and one clear TPA structure in the dawnside southern hemisphere. Precipitating particle data reveal that the TPA in the southern hemisphere and that near the dawnside auroral oval in the northern hemisphere are associated with precipitating electrons and ions, but the TPA near the magnetic pole in the northern hemisphere is associated with electron-only precipitation. These observational results imply that the formation of TPAs is not limited to northward IMF conditions and that the TPAs could be located not only on open field lines connected to the northward draped IMFs over one hemisphere magnetopause, but also on closed field lines rooted on both hemispheres even under the radial IMF conditions.
Setting up of the Indian Tsunami Early Warning System (ITEWS): National and International Interactions for the Success of ITEWS
Authors: Gupta Harsh
Published: March 2020

The 26 December 2004 Sumatra earthquake of Mw 9.2 and the resultant tsunami that claimed over 2,50,000 human lives is probably the most destructive natural disaster of the 21st Century so far. Although the science of tsunami warning had advanced sufficiently by that time, with several tsunami warning centers operating in various oceans, no such system existed for the Indian Ocean. Here we present the discussions and interactions held in India and globally to convince setting up of ITEWS. False tsunami alarms subsequent to 26 December 2004 earthquake had developed a sense of scientific disbelief in the public and to a certain extent in Government of India. We demonstrated to the national and international community that there are only two stretches of faults that could host tsunamigenic earthquakes as far as the India Ocean is concerned. These are: 1) a stretch of some 4000 km of a fault segment extending from Sumatra to Andaman Islands and 2) an area of about 500 km radius off the Makaran Coast in the Arabian Sea. And if we cover these two areas with ocean bottom pressure recorders, the problem of false alarms would be reduced to a large- extant. This plan was finally agreed to and necessary financial, logistic and technical support was made available. The setting up of the ITEWS started in middle 2005 and was completed in August 2007. It has performed very efficiently since then. Over the past ~ 8 years, it monitored ~ 500 M ≥ 6.5 and provided advisories. As against the requirement placed by IOC of issuing an advisory in 10 to 15 minutes time, ITEWS has been doing it in ~ 8 minutes. Since its inception in 2007, no false alarm has been issued and it is rated among the best in the world.

IOC has designated ITEWS as the Regional Tsunami advisory Provider (TSP) Indian Ocean Regional Tsunami Center.
Millennial scale land subsidence history along the southern China coast
Authors: Xiong Haixian , Zong Yongqiang
Published: March 2020

Estimation of coastal land subsidence rates due to GIA and tectonic factors on millennial scale has become an urgent task for the hazard assessment of future rising sea level. Whilst geophysical simulation is a promising approach, the modeling uncertainty is still difficult to constrain due to the lack of accurate sea-level data. Another practical approach is based on the present elevations of paleo indicative landforms of known ages, such as coastal terraces and MIS5e marine sediments. However, this method also suffers from uncertainties associated with the measurements of landform relicts. In order to obtain a robust estimation of long-term coastal subsidence rates along the southern China coast, an active economic zone vulnerable to future sea-level rise, this study applies a statistical method to determining the high-probability land subsidence histories of six coastal sectors (the Yangtze Delta, Fujian & Taiwan Strait, Han River Delta, East Guangdong, Pearl River Delta, and West Guangdong & Hainan Island) over the past six millennia. The land subsidence histories of the six sites are produced by comparing their RSL histories reconstructed from qualified sea-level index points (SLIPs) with those of the Malay Peninsula, based on the assumption that the Malay Peninsula has been tectonically stable. Therefore, the RSL history at each site is considered as a function of eustatic sea-level change, global GIA (e.g. ocean siphoning), local GIA (e.g. coastal levering) and tectonic movement. Therefore, a subtraction of RSL histories between the China sites and the Malay Peninsula will result in land vertical movement trends consisting of both the local GIA and tectonic components. The result shows that the coast of southern China has been undergoing linear land subsidence over the past 6000 years. The subsidence rates of the six sites average at about 1.2±0.1 mm/yr, with the highest rate of 2.1±0.1 mm/yr in the Han River Delta and the lowest rate of 0.5±0.1 mm/yr in West Guangdong & Hainan Island. In order to separate the tectonic subsidence rate from the local GIA rate for each site, outputs of GIA models (a 3D Earth model HetM-LHL140 coupled with ICE-6G_C) for China and the Malay Peninsula were obtained. The result suggests that the local GIA component (mainly coastal levering) might have accounted for half of the land subsidence along the China coast over the past 6000 years. This estimation of long-term land subsidence rates should form an integral part of the hazard assessment for the coastal communities in China.
Deducing the role of eolian dust sedimentation during soil forming periods on mineral magnetic records and its implications for paleoclimate reconstructions
Authors: Jordanova Diana , Jordanova Neli
Published: March 2020

Obtaining reliable global and regional records of the past climatic changes during the glacial Pleistocene is of prime importance for building up consistent climate models of the near and far future. Magnetic signature along sequences of alternating loess and (paleo)soil units from the terrestrial environments is considered as semi-continuous record of climate change in the geological past. However, soil formation in aeolian landscapes may occur under different and changing conditions of dust sedimentation. Viewing from this standpoint the depth variations of several rock magnetic characteristics along profiles of Holocene soils from low Danube area allowed us to establish a set of criteria for identification of the past regimes of aeolian sedimentation persisted during the soil forming periods. A conceptual model for the time evolution of the grain size of the pedogenic magnetic fraction  with soil depth is proposed,  which is build upon  the mechanism of soil formation – accretional or  stable land surfaces,  or a combination of the two. According to the proposed conceptual model, discrimination between accretional soils and soils developed without dust additions during soil forming period can be done. Accretional soils are characterized by parallel changes in grain size sensitive magnetic proxies. Soils, developed at stable landscape conditions show gradation of the depths at which maximum enhancement of various proxies occurs with deepest occurrence of the maximum in frequency dependent magnetic susceptibility, followed by depth of maximum anhysteretic susceptibility and the normalized anhysteretic to isothermal remanence acquired at 100mT field. It is shown that the mean coercivity of the pedogenic component of accretional soils is higher than that of soils developed without eolian input at equal temperature conditions because of the soils’ thermal gradient and different depths, at which pedogenic minerals form in the two settings.
Impact of tropical ocean SSTs on the variability and predictable components of seasonal atmospheric circulation in the North Atlantic – European area
Authors: Ivasić Sara , Herceg Bulić Ivana
Published: March 2020

Atmospheric variability and predictable components over North Atlantic-European area were analyzed using an atmospheric general circulation model of intermediate complexity (ICTP AGCM). In order to extract individual modes of variability occurring in the ensemble of numerical simulations, EOF analysis was applied onto the fields of the 200 hPa geopotential height and total precipitation. The same variables were selected for the signal-to-noise optimal patterns method, which identifies the patterns that maximize the signal-to-noise ratio, following Straus et al. (2003).

To detect the potential impact of tropical ocean SSTs, five experiments based on a 35-member ensemble of simulations for the 1855 – 2010 period were conducted. Each experiment was forced with observed SST anomalies prescribed in different ocean areas: the experiment with climatological SSTs (i.e. no SST forcing), SST anomalies prescribed globally, SST forcing prescribed in the entire tropical zone, SST forcing constrained to the tropical Atlantic, and the experiment with SST forcing constrained to the tropical Pacific.

SST forcing impacts the interannual variability of the geopotential height and total precipitation, represented with EOF1 and EOF2 patterns, only in the frequency of occurrence of a certain atmospheric mode. In the winter season the first EOF pattern projects onto the NAO, while the second EOF pattern projects onto the Atlantic ridge.

The signal-to-noise optimal patterns method has shown that the optimal patterns and signal-to-noise ratio are affected by the boundary forcing of the oceans.
Influence of Near Real-Time Green Vegetation Fraction Data on the Numerical Weather Prediction in WRF over North China
Authors: Lu Bing , Zhong Ji-Qin , Wang Wei , Tang Shi-Hao , Zheng Zhao-Jun
Published: March 2020

Green vegetation fraction (GVF) has a prominent influence on the partitioning of surface sensible and latent heat fluxes in numerical weather prediction models. However, the multi-year monthly GVF climatology, which is the most commonly-used representation of vegetation states in models, has limited ability to capture the real-time vegetation status. In our study, a near real-time (NRT) GVF dataset generated from 8-day composite of the normalized difference vegetation index (NDVI) is compared with the 10-year averaged monthly GVF provided by the Weather Research and Forecasting (WRF) model. We examine the annual and inter-annual variability of the GVF over North China in details. Many differences of the GVF between the two datasets are found over the dryland cropland and grassland areas. Two experiments using different GVF datasets are performed to assess the impact of the GVF on the forecasts of screen-level temperature and humidity for one year. The results show that using the NRT GVF can lead to a widespread reduction of 2-m temperature in the order of 0.5 ℃, and an increase of 2-m humidity during the warm season. An evaluation against in-situ observations displays an overall positive impact on the near surface parameter forecasts. Over the dryland cropland and grassland areas, a quantitative validation shows that the root mean square errors of 24-h forecasts decline by 9%, 10% and 6% for 2-m temperature, 2-m specific humidity and 10-m wind speed, respectively, in May of 2012. Our study demonstrates that the NRT GVF can provide a more realistic representation of vegetation state which in turn helps to improve the short-range forecasts in the arid and semiarid regions of North China.
Use of laser spectroscopy to evaluate the influence of soil storage on N2O emission
Authors: Ding Yang , Heiling Maria , Zaman Mohammad , Resch Christian , Dercon Gerd , Heng Lee Kheng
Published: March 2020

Accurate measurements of nitrous oxide (N2O) fluxes from soils are necessary to understand dynamic changes in soil nitrogen cycles. Laboratory incubation experiments provide a controlled condition to measure these N2O fluxes. Before incubation experiments, soils are often stored at certain conditions to minimize the microbial activities. However, the effect of soil storage on N2O emission has been poorly studied. A laboratory incubation experiment was conducted using disturbed soils to study the storage effect. The soil was sieved to 2mm and the following four treatments were tested: fresh undisturbed (FU), fresh sieved (FS), fridge stored at 4ºC (ST), and stored at room temperature after drying (PI). After soil samples were brought to 60% water-filled pore space (WFPS), 15N labelled urea (1 At%) was applied at the rate of 50 mg N kg-1 soil and the soil was incubated at room temperature (23 ºC). The N2O fluxes were measured for 7 weeks using off-axis integrated cavity output spectroscopy (OA-ICOS, Los Gatos Research, California, USA). Cumulative N2O fluxes and Keeling plot intercepts (δ15N source) were calculated. The results showed that soil storage has a significant effect on N2O emission. Over the 7-week period, ST produced the highest cumulative N2O emissions (2.70 µg N g-1 soil) as well as the largest amount of N derived from fertiliser (Ndff) (1.4 µg N g-1 soil). FU produced the lowest cumulative N2O emissions (1.0 µg N g-1 soil) but the largest amount of N derived from soil (Ndfs) (0.6 µg N g-1 soil). The daily N2O fluxes of FS and FU declined rapidly after the peak emissions, but the fluxes of PI and ST fluctuated after the peaks. These results indicate that soil storage affects microbial processes and therefore N2O emissions. Our results suggest using fresh soil to avoid storage effects. If this is not possible the effect of soil storage should be considered before the experiment.  
Statistical prediction of 20th century European summer temperatures based on ERA20c reanalysis data
Authors: Pyrina Maria , Wagner Sebastian , Zorita Eduardo
Published: March 2020

An alternative to dynamical seasonal prediction of European climate is statistical modeling. Statistical modeling is an appealing and computationally effective approach for producing seasonal forecasts by exploiting the physical connections between the predictand variable and the predictors. We assess the seasonal predictability of summer European 2m temperature (T2m) using canonical correlation analysis. Seasonal means of spring Soil Moisture (SM), Sea Level Pressure (SLP) and Sea Surface Temperature (SST) are used as predictors of mean summer T2m. For SSTs, we test the potential predictability of T2m using three different regions. These regions include what we define as: Extratropical North Atlantic (ENA), Tropical North Atlantic (TNA), and North Atlantic (NA). The predictability is explored in the ERA20c reanalysis and in comprehensive Earth System Model (ESM) fields. The results are provided for the European domain on a horizontal grid of 1°x1° degrees.

In order to identify the local T2m predictability related to the different predictor variables, we first built Univariate Linear Regression models, one for every predictor. The regression models are calibrated and validated during 1902-1950 and a prediction is provided for the periods 1951-1998, 1951-2004, and 1951-2008, respectively. The resulting correlation maps between the original and the predicted T2m anomalies showed that for the predictor variables SLP, SM, and SSTENA the results of the experiments using ESM data share similar T2m predictability patterns with the results of the experiments using reanalysis data. Most prominent disagreements between the predictability patterns resulting from ESMs and from ERA20c refers to the T2m prediction that utilizes tropical SSTs. SM is identified as the most important predictor for the summer European temperature predictability.

The ERA20c data show that the SM predictor field can be used for the T2m prediction over most of our study region west of 15° E and that the ENA SSTs can be used for the prediction over Europe east of 15° E. The resulting gridded correlation coefficients vary between 0.3 and 0.5. These results are not sensitive to the prediction period and to the number of Canonical Coefficients used in the regression model. Our approach complements existing numerical seasonal forecast frameworks and can be implemented for ensemble prediction studies.
Study of the wet bulb in drip irrigation in stratified soils using HYDRUS
Authors: Roldán Cañas José , Zapata Sierra Antonio Jesús , Reyes Requena Rafael , Moreno Pérez María Fátima
Published: March 2020

The “enarenado” (sand-covering soil) is a technique used in greenhouses located in the southeast of Spain that consists of placing a layer of soil between 20 and 40 cm above the original material, a thin layer of organic matter and above it a layer of sand of about 5 to 10 cm.

It is necessary to know the shape of the wet bulb produced by the emitters for a correct design and management of the drip irrigation systems. In stratified soils, as in the case of “enarenado” soils, the distribution of water can change substantially with respect to the case of homogeneous soils. The objective of this work is to present the methodology of data acquisition and the actions carried out so far to obtain a model that precisely defines the evolution of humidity in wet bulbs generated in “enarenado” soils characteristic of intensive horticultural crops.

The tests have been carried out at the facilities of the IFAPA Center La Mojonera, Almería, SE Spain. The textures of the added soils are sandy loam and clay loam, representative of the horticultural crops of Almeria. The crop was pepper , Mazo variety, planted on September 15, 2018 in the two selected greenhouses. The irrigation is automatic, with drippers of nominal flow Qn = 3 l / h, self-compensating, anti-drainage of Netafim. Irrigation control is carried out using classic tensiometers with built-in pressure transducer.

The humidity has been measured at 10 points distributed around a dripper, 7 probes at 5 cm deep in the added soil layer and 3 probes at 18 cm depth, near the original soil layer. The sensor used is TE5 Decagon. The plantation frame coincides with that of the drippers, Sg = 50 cm and Sr = 120 cm, for this reason the probes were placed up to half of the plantation frame.

The data collected show a small variation in humidity over time. That is, the added soil, with a clayey texture, quickly redistributes moisture and the probes register very small variations.

Once the values specified in the methodology have been measured, the theoretical humidity retention curves of greenhouse soils have been calibrated. With the data collected, the system has been simulated by completing the fields that the Hydrus model needs. This operation has been specified in the definition of a simple, multi-layered 3D model. In general, the model predicts moisture behavior well in the conditions set.
Impacts of land use change and climatic effects on streamflow in the Chinese Loess Plateau: a meta-analysis
Authors: Chen Hao , Fleskens Luuk , Baartman Jantiene , Wang Fei , Moolenaar Simon , Ritsema Coen
Published: March 2020

Abstract: Land use and climate change are recognized as two major drivers affecting surface streamflow. On the Chinese Loess Plateau, implementation of several land restoration projects has changed land cover in recent decades. The main objectives of this study were to understand how streamflow evolved on the Loess Plateau and how land use and climate change have contributed to this change. In this study, we selected 22 hydrological modelling studies covering 25 different watersheds in the Loess Plateau and we performed a meta-analysis by using the hydrological and metrological data collected from these studies. The results indicate a streamflow decrease in 41 of a total of 52 case studies whereas precipitation change was found to be non-significant in the majority of the cases. Streamflow reduction was estimated to be -0.46mm/year by meta-analysis across all case studies. Land use change was estimated to have 63.52% impact on the streamflow reduction whereas climate change accounted for 36.48% of the impact. Using meta-regression, an increasing soil and water conservation area was found to be positively correlated to streamflow reduction. We conclude that in the Chinese Loess Plateau, streamflow shows a decreasing trend and land restoration is the major cause of this reduction. To the knowledge of the authors, this is the first study that estimates streamflow dynamics across many watersheds on the entire Loess Plateau.
Carbon dioxide and methane RemoTeC retrievals from GOSAT (2009-2019) and GOSAT-2 (2019)
Authors: Haun Markus , Suto Hiroshi , Butz André
Published: March 2020

The Japanese Greenhouse gases Observing SATellite (GOSAT), in orbit since January 2009, and its successor GOSAT-2, in orbit since October 2018, are dedicated to enhancing our knowledge of the carbon cycle. We use our RemoTeC full-physics algorithm to infer atmospheric concentrations and auxiliary parameters from the measured solar SWIR radiances backscattered at the earth´s atmosphere and surface. Accuracy requirements are a major challenge for these space-based measurements of column-averaged dry-air mole fractions of carbon dioxide and methane (XCO2 and XCH4).

Here we present 1) a consolidated ten years GOSAT XCO2 and XCH4 dataset and 2) first results for GOSAT-2 XCO2 and XCH4 retrievals. For GOSAT, 4.8 % of all measurements pass our cloud filter, based on the O2 A-band signal and several quality filters. For validation and bias-correction, we use collocated measurements from ground-based stations of the Total Carbon Column Observing Network (TCCON). The dataset shows a scatter of well below 1 %. For GOSAT-2, we are able to reliably process measurements in land nadir and ocean glint geometry. In addition to the retrieval windows implemented for GOSAT, we use the spectral ranges at 4290 - 4328 cm-1 and 4354 - 4441 cm-1 to retrieve carbon monoxide and nitrous oxide concentrations. We evaluate instrument performance and precision by comparing XCO2 and XCH4 retrievals to both collocated GOSAT and ground-based TCCON measurements.
Estimation of potential surface ponding in agriculture using UAV-SfM
Authors: Straffelini Eugenio , Chen Xuewei , Cucchiaro Sara , Michieli Sofia , Chen Jianping , Tarolli Paolo
Published: March 2020

Among the environmental problems that could affect agriculture, one of the most critical is ponding. Ponding is the water storage on the surfaces in concavities or small depressions, due to soil saturation. It can seriously affect crops and the management of agricultural landscapes. It is caused by prolonged rainfall events, soil type, or by wrong mechanization practices. Indeed, the increased pressure of heavy machinery can cause topsoil compaction or a subsoil hard pan directly under the ploughing depth, inducing run-off, soil loss and waterlogging. In order to better understand this issue, and therefore provide suitable solutions to reduce ponding risk, it is necessary to represent in details the surface morphology. In the last decade, a range of new remote-sensing techniques have led to a dramatic increase in terrain information, providing new opportunities for a better understanding of Earth surface processes based on geomorphic signatures. Among these, the Unmanned Aerial Vehicles (UAVs) combined with the Structure-from-Motion (SfM) photogrammetry technique represent undoubtedly the most interesting advance in the Earth observation and understanding of Earth surface processes. UAV-acquired imagery may provide a low-cost, rapid, and flexible alternative to airborne LiDAR for geomorphological mapping.

In this work UAV-SfM data are used to obtain high-resolution Digital Terrain Model (DTM) useful to analyze and evaluate the risks of water ponding at farm level in a mid-size agricultural Mediterranean catchment in northern Italy. Intensive photogrammetric surveys were carried out using a UAV while a GNSS in RTK (Real-Time Kinematic) mode was used to collect Ground Control Points (GCPs) and Check Points (CPs), fundamental for georeferencing process and SfM error analysis. The potential water depth was calculated using the Relative Elevation Attribute (REA) algorithm, a methodology successfully used in other contexts (Tarolli et al. 2019). The detection of more pronounced concavities and convexities allowed an estimation and mapping of the potential ponding conditions, thus providing a useful indication for a better environmental management in agriculture.

 

References

Tarolli, P, Cavalli, M., Masin, R., (2019). High-resolution morphologic characterization of conservation agriculture. Catena, 172, 846–856, doi: 10.1016/j.catena.2018.08.026
Quasi-stationary current sheets of the solar origin in the heliosphere
Authors: Kislov Roman
Published: March 2020

The solar magnetic field (SMF) has historically been considered as dipole in order to build models of the radially expanding corona, that is, the solar wind in the solar minimum. The simplified approach suggests the existence of only one quasi-stationary current sheet (QCS) of solar origin in the heliosphere, namely, the heliospheric current sheet (HCS). However, the SMF becomes more complicated over the solar cycle, comprising higher-order components. The overlapping of the dipole and multipole components of the SMF suggests a formation of more than one QCS in the corona, which may expand further to the heliosphere. We study the impact of the quadrupole and octupole harmonics of the SMF on the formation and spatial characteristics of QCSs, building a stationary axisymmetric MHD model of QCSs in the heliosphere. It is shown that if the dipole component dominates, a single QCS appears in the solar wind at low heliolatitudes as the classic HCS. In other cases, the number of QCSs varies from one to three, depending on the relative input of the quadrupole and octupole components. QCSs possess a conic form and may occur at a wide variety of heliolatitudes. The existence of QCSs opens wide opportunities for explanations of puzzling observations of cosmic rays and energetic particles in the heliosphere and, at the same time, raises a risk of misinterpretation of in situ crossings of QCSs because of mixing up the HCS and higherheliolatitude QCSs, which can be significantly disturbed in the dynamical solar wind.
The teleconnection between the Siberian snow-albedo feedback and the spring East Asian dust cycle : based on Last Millennium Ensemble
Authors: Liu Heng
Published: March 2020

According to the reanalysis data of recent years, the Siberian snow-albedo feedback is found to play a crucial role on the spring East Asian dust cycle by influence local energy budget and circulation. By analyzing the CESM Last Millennium Ensemble conducted by National Center for Atmospheric Research (NCAR), we found that the spring East Asian dust burden is significantly correlated with the snow-albedo over Siberia during the past millennium. The correlation coefficient between the snow depth over Siberia and the East Asian dust burden reaches to 0.56. The cloud fraction over Siberia is also correlated with the dust burden with a coefficient of 0.40. The Siberian snow cover reflects shortwave radiation and cools down the lower and middle troposphere, which leads to more clouds and snows occurring over Siberia. The increased cloud cover therefore reflects more shortwave to cool down the surface as a positive feedback. The cooling of lower troposphere over Siberia induces cyclonic wind anomalies around the region, enhances the westerly winds over the East Asian deserts which locate on the south side of Siberia and finally promotes the East Asian dust cycle.
The influence of the brittle-ductile transition zone on aftershock and foreshock occurrence
Authors: Petrillo Giuseppe , Landes François , Lippiello Eugenio , Rosso Alberto
Published: March 2020

The organization in time, space and energy of aftershocks is characterized by scaling behaviors with exponents which are quite universal. At the same time, deviations from the universal behavior are sometimes observed and they have been proposed as a tool to discriminate aftershock from foreshock occurrence. Here we show that the change in rheological behavior of the crust with increasing depth, from velocity weakening to velocity strengthening, represents a viable mechanism to explain statistical features of both aftershocks and foreshocks. More precisely, we present a model of the seismic fault described as a velocity weakening elastic layer elastically coupled to a velocity strengthening visco-elastic layer. The model has only two parameters: one controls the degree of heterogeneities of the static friction force and the other quantifies the stress transferred between the two layers. We show that the statistical properties of aftershocks in instrumental catalogs are recovered at a quantitative level without any fine-tuning. This robustness provides a justification for the universality of aftershock phenomenological laws and supports our modelling assumptions. We also find that synthetic foreshocks mimic those observed in instrumental catalogs, opening the way for subtle forecasting tools.
The range of flow structures fitting Jupiter's asymmetric gravity field
Authors: Duer Keren , Galanti Eli , Kaspi Yohai
Published: March 2020

Jupiter's North-South asymmetric gravity field, measured by the Juno spacecraft, allowed estimating the depth of the zonal jets trough the relation between the measured density anomaly and the flow. This analysis was based on a combination of all four measured odd gravity harmonics, so the direct effect of each of them on the flow profile has not been investigated. Moreover, past calculations assumed that the cloud-level zonal wind maintains its meridional structure with depth; However, the Juno microwave radiometer measurements imply that a vertically dependent meridional profile might be more suitable, due to the reasonable relation between the Nadir brightness temperature profile and the zonal wind. In this study, we analyze in detail the possible range of structures of Jupiter’s deep jet-streams, fitting each of the Juno's measured asymmetric gravity harmonics. Specifically, we examine the possible vertical structure of Jupiter’s deep jet streams, different meridional structures of the cloud-level zonal wind and depth-dependent meridional profile compatible with the Nadir temperature tendency. We find that each odd gravity harmonic constrains the flow at a different depth, with J3 being the most dominant at depths below 3000 km, where the electrical conductivity becomes significant. J5 is the most restrictive harmonic overall, and J9 does not constrain the flow at all if the other odd harmonics are within the measurement range. Deep flow profiles constructed from perturbations to the cloud-level winds allow a more extensive range of solutions, yet when the patterns differ substantially from the cloud-level observed wind profile, the ability to match the gravity data reduces significantly. Random zonal wind profiles, unconnected to the cloud-level profile allow almost no solutions for the gravity data, and only 1% of the tested wind profiles yield any solution. Overall, we find that while interior wind profiles that diverge considerably from those at the cloud-level are possible, they are statistically unlikely. Finally, we find that meridional smoothing of the wind with depth, according to the Juno MWR brightness temperature profile, still allows fitting the measured gravity signal within the uncertainty range.
Impacts of conservation agriculture on soil nitrogen pools and microbial physiology
Authors: Schnecker Jörg , Bodner Gernot
Published: March 2020

Conservation or regenerative agriculture, i.e. reduction of mechanical soil disturbance, introduction of crop rotations, and especially cover crops as a form of natural soil amendment, has been shown to increase soil organic matter contents as well as soil health. One mechanism behind the increase in organic carbon under regenerative agriculture could be an increase in microbial biomass, as well as an enhanced carbon use efficiency (CUE) of the soil microorganisms in these systems. Such changes in microbial biomass and activity could also influence soil nitrogen (N) cycling. Here we show first results of on-farm research at four sites in Austria comparing crop fields under regenerative agriculture practices with conventional practices, and nearby perennial grasslands at each site. The four sites span different climate gradients, soil types and textures.

Soil organic carbon (SOC) content ranged from 1 to 2.3% in the agricultural soils and was significantly higher under regenerative management compared to conventional practices in two out of four sites. SOC contents in perennial grasslands were up to 5% and always higher than in agricultural fields. Extractable organic carbon was similar in the two agricultural fields of the respective site, while grasslands diverged. Microbial biomass carbon was highest in grasslands at all sites and significantly higher in fields under regenerative agriculture compared to conventional agriculture at three out of four sites.

Total nitrogen was highest in perennial grasslands at all sites, and similar in regenerative and conventional fields. The form of N however differed between soils under conventional and regenerative agriculture. Dissolved N, expressed per g total N was significantly higher or tended to be higher in conventional compared to regenerative agricultural fields. From this dissolved pool a higher proportion was in inorganic N forms that are more prone to leaching and gaseous loss compared to organic N forms. In soils from regenerative agricultural fields a higher proportion of the total N was found in the microbial biomass. This pool is considered to be highly dynamic, but also protected against losses. Less N in dissolved and inorganic form as well as a higher proportion of N in the microbial biomass indicates that the N cycle is more closed in soils managed regeneratively versus conventional.

A greater importance of the microbial biomass could also have effects on soil C cycling. Higher microbial biomass is often related to increased carbon use efficiency, which in turn could indicate increased soil carbon sequestration. The already mentioned results will thus be discussed with further measurements of microbial respiration, growth and CUE.
A meta-analysis of ecosystem services values of European floodplains: database setup and case study application
Authors: Perosa Francesca , Fanger Sami , Zingraff-Hamed Aude , Disse Markus
Published: March 2020

The concept of ecosystem services (ES) can help to build a bridge between hydrology, nature, and society. In recent decades, Europe experienced severe catastrophic flood events. Simultaneously, the Floods Directive calls for the inclusion of ES as additional decisional support in flood management. In order to implement flood risk prevention while maximizing the benefits of nature to the society, a better understanding of the floodplains’ ES is required.

The study on the added value of floodplains in Europe has the aim to provide scientific support and answers to the following questions:

What are the most frequent ES in European flooding areas’ ecosystems? What are the differences and trends of investigated ES among the European countries?

Which environmental and societal factors are significant to explain the monetary value of floodplains’ ES in areas where no studies haven’t been conducted yet?

Can ES be used in real case studies to support decision-making in the field of flood risk management?

To answer these questions, a database containing ES studies and their assessed results in the last 20 years was set up and enriched with freely available geo-physical (e.g. land cover) and socio-economic (e.g. population) data. A meta-regression analysis is then applied to the ES values with the aim of extracting a value-transfer function for areas that haven’t been investigated yet. This allows estimating the ES monetary values of proposed floodplain restoration measures in different pilot areas of the Danube River Basin. The work done will help to prove the profitability of nature-based solutions to decision-makers and stakeholders affected by flood risk.
Lower Danube loess - a crucial palaeoclimatic archive for the last glacial cycle in Southeast Europe
Authors: Pötter Stephan , Bösken Janina , Obreht Igor , Schulte Philipp , Veres Daniel , Hambach Ulrich , Zeeden Christian , Marković Slobodan , Lehmkuhl Frank
Published: March 2020

The vast Pleistocene aeolian sediments of the Lower Danube Basin are an important archive of Quaternary palaeoclimate dynamics in Southeast Europe. The intercalation of loess layers and fossil soils, so called loess-palaeosol sequences (LPS) are interpreted as the results of oscillating climate phases in the past. However, the characteristics of these LPS vary quite strongly, since they are influenced by various factors. Those factors are mainly the (palaeo-) climate, the (palaeo-) relief and the availability of source material, which differ notably, even at a regional scale. Taken that into account, it is crucial to consider local characteristics while comparing data from different LPS.

Against this backdrop, we compare two LPS from the dry Bărăgan steppe area in southeast Romania: Vlasca (VLA) and Balta Alba Kurgan (BAK). The two sections are approx. 100 km afar and developed under different geomorphic and climatic situations, resulting in varying accumulation rates and post-depositional alterations. Vlasca is a natural exposure on the left bank of the Danube River, whereas BAK is situated in a road cut, approx. 15 km south of the Carpathian bending. The two sites show remarkable differences concerning accumulation rates, grain size, colour, geochemical characteristics as well as magnetic properties, which are interpreted as the results of sediment availability, depositional milieu and especially post-depositional alterations. The variations and the commonalities are used, together with the chronological framework, to better understand the palaeoclimatic evolution of the Lower Danube Basin within the last glacial cycle and to gauge possible ramifications of palaeoclimatic variations on the migration of modern humans.
Bimodal distribution of the solar wind using data from ACE spacecraft.
Authors: Larrodera Carlos , Cid Consuelo
Published: March 2020

The main goal of this work is to separate the behavior of the two types of quiet solar wind at 1 AU: fast and slow.
Our approach is a bi-Gaussian distribution function, formed by the addition of two Gaussian distribution functions, where each one represents one type of wind. We check our approach by fitting the bi-Gaussian to data from ACE spacecraft. We use level 2 data measured during solar cycles 23 and 24 of different solar wind parameters, including proton speed, proton temperature, density and magnetic field. Our results show that the approach is fine and only transient events departs from the proposed function. Moreover, we can show bi modal behavior of the solar wind at 1 AU, not only for the proton speed, but also for the other analyzed parameters. We also check the solar cycle dependence of the different fitting parameters.