bluuebunny/crossref_metadata_2025 huggingface dataset:
A review on the spread of prehistoric agriculture from southern China to mainland Southeast Asia
Authors: Gao Yu , Dong Guanghui , Yang Xiaoyan , Chen Fahu
Published: March 2020

The origins and spread of agriculture was one of the milestones in human history. When and how prehistoric agriculture spread to mainland Southeast Asia is highly concerned, which contributed to the formation of modern Austroasiatic in this region. Previous studies mainly focused on the time and route of rice agriculture’s introduction into Southeast Asia while millet agriculture was not paid properly attention. Here we analyze 312 14C dating data yielded from charred seeds of rice (Oryza sativa), foxtail millet (Setaria italica) and broomcorn millet (Panicum miliaceum) from 128 archaeological sites in China and mainland Southeast Asia. The result shows that millet farming was introduced to mainland Southeast Asia in the late third millennium BC and rice farming was in the late second millennium BC. The agriculture of mainland Southeast Asia might originate from three areas, Southwest China, Guangxi-West Guangdong and coastal Fujian. The spread route of ancient agriculture in Southwest China is close to the “Southwest Silk Road” recorded in literature, which infers there was possibly a channel of cultural exchanges on the eastern margin of Tibetan Plateau already in the late Neolithic period, laying the foundation of the Southwest Silk Road later.
Flower Power: flower-strips host bees & sequester carbon in soils
Authors: Vetter Vanessa , Jungkunst Hermann , Schützenmeister Klaus , Buhk Constanze
Published: March 2020

Flower-strips are increasingly recognized as mandatory elements in agricultural landscapes for pollinators to survive. In this study, we raised the hypothesis that flower-strip traits additionally affect biogeochemical cycling towards climate change mitigation. Therefore, we investigated soil carbon and nutrients stocks in paired comparison to adjacent land use and looked at water retention.

Two study farms of 50 ha in southern Germany were sampled once in spring, summer and autumn. The examined flower-strips of both farms were sown in 2011 and are in use since then. Pairwise sampling reduces the influence of the expected high variation in soil parameters. For each pair we sampled 3 depths: topsoil (0-5 cm), plow horizon (20-25 cm) and subsoil (30-35 cm). Different parameters of soil carbon, nitrogen, nutrients and water will be presented with a focus on clay bonded carbon.

Preliminary results indicate that flower-strips significantly increased nitrogen availability, soil carbon stocks and accordingly showed a trend to improve the water storage capacity in the plow horizon. We did not observe a statistically significant effect on nutrient availability.

Provided that these results will be confirmed, flower-strips traits could go beyond the important trait of giving pollinators a home in vast agricultural landscapes. By slightly increasing the amount of flower-strips in these landscapes, a significant increase in carbon sequestration and water retention will be achievable adding to the 4 per mille goal of the UN.
OH reactivity in three major city clusters of China in ozone seasons: insights for regional ozone formation
Authors: Lou Shengrong , Shen Xiangsen , Li Xin , Wang Qian , Liu Shuoying
Published: March 2020

OH radical is the key driver of the photochemical process and closely related to ozone formation. OH reactivity is the quantification of OH radical sink in ambient air. In this study, in-situ OH reactivity measurements are carried out in Shenzhen, Chengdu and Changzhou, three typical cities in major city clusters of China, during their ozone pollution seasons. The measured OH reactivity is ranging from 5~35 s-1 under various meteorological conditions and trace gas concentrations. Aldehydes such as HCHO and acetaldehyde, mainly from the secondary formation of VOCs, are the principal contributors at day time. Primary VOCs such as toluene and biogenic VOCs such as isoprene play different roles in three measurement locations. The missing OH reactivity, which is defined as the OH reactivity that cannot be explained by trace gas measurements, are evaluated by in-situ measurement results as well as an observation-based model. Gas-phase secondary pollutants could be the main source of the missing OH reactivity. The sensitivity tests by the OBM model show ozone production in all areas is mainly VOC-limited but the key precursors of ozone are not identical, leading to different control strategies.
Model evaluation for Heatwaves over South Korea in CMIP6 models
Authors: Oh Ji-Seon , Kim Maeng-Ki , Yu Dae-Geun , Sang Jeong
Published: March 2020

In this study, we defined diagnostic indices to evaluate the CMIP6 models based on the heatwaves mechanisms of Korea presented in previous studies. Based on this, the simulation performance of the model was quantitatively evaluated using Relative Error (RE), Inter-annual Variability Skill-score (IVS), and Correlation Coefficient (CC). The REs in diagnostic indices are still large, especially in heat wave circulation index (HWCI) and Indian summer monsoon rainfall index (IMRI), which is mainly due to weak convective activity bias over the northwestern Pacific Ocean and the northwestern India. However, the IVSs in diagnostic indices have been improved overall in the CMIP6 compared to the CMIP5, especially in the IMRI. The CC between the daily maximum temperature (TMAX) and the diagnostic factors in the model is very higher in HWCI than other indices, indicating that the convective activity over the northwestern Pacific is very important in heat wave in Korea. As a result, the total ranking of the model performance for heatwaves in Korea suggested that EC-Earth3-Veg, EC-Earth3, and UKESM-1-0-LL ranked high in CMIP6.

 

This work was funded by the Korea Meteorological Administration Research and Development Program under Grant KMI(KMI2018-03410)
Wildfires in Europe: the role of land use/land cover changes
Authors: Parente Joana , Tonini Marj , Stamou Zoi , Koutsias Nikos , Pereira Mário
Published: March 2020

Wildfire (WF) has the potential to occur in more than 30% of the worldwide land area, in many different biomes/ecosystems/land cover types, where it is controlled mainly by the environmental drivers such as vegetation structure, meteorological/climate conditions, and human activities. On the other hand, land use/land cover changes (LULCC) are one of the most important global alterations of the environment. In the last decades, Europe registered significant-high fire incidence and LULCC between all land cover classes. In the 2000 – 2018 period, according to the European Forest Fire Information System (EFFIS), Europe was affected by 18 882 WFs which burned 6 887,713 ha. According to CORINE land cover maps, the observed LULCC area in Europe for the same period was of 23,510,075 ha. Recent studies suggested that regional LULCC in the last decades promoted the occurrence of more and larger WF, in some European regions. Therefore, the main objectives of this study were to assessed the LULCC in and around burnt areas (BAs) during the 2000–2018 period. This study benefits from the use of reliable CORINE inventories and EFFIS BA product. A geospatial methodological approach was implemented to identify and quantify LULCC and to characterize the relationship between LULCC and WFs in Europe. This research provides a detailed characterization of the LULCC in and around BAs in Europe, and attempts to contribute to a better management of the landscape, urbanization and wildland-urban interface to reduce related losses in the natural and human system including losses of life, property and assets.
Modelling and mapping global soil information
Authors: Poggio Laura , Moreira de Sousa Luis , Heuvelink Gerard , Kempen Bas , Bai Zhanguo , Turdukulov Ulan , Ruiperez Gonzalez Maria , Ribeiro Eloi , Batjes Niels , van den Bosch Rik
Published: March 2020

Soil information is fundamental for many global applications, such as food security, land degradation, water resources, hydrology, climate change and ecological conservation. To address these diverse needs, it is important to provide free, consistent, easily accessible and standardized soil information. SoilGrids meets these requirements being a  global product supporting global modelling and providing complementary information for the development of regional and national products in data-poor areas. This presentation will focus on the methodological aspects for modelling and mapping of global soil information. We describe the selection of models for global mapping using quantile random forest and recursive feature elimination to obtain a parsimonious model. We also use a refined cross-validation procedure to account for bias caused by spatial differences in sampling density at different depths. SoilGrids also quantifies location-specific uncertainty at global level by computing 90% prediction interval limits. 
Characterizing Hydrological Fluxes of Lesser Himalayan hillslopes
Authors: Nanda Aliva , Sen Sumit
Published: March 2020

Hillslope-scale studies play a vital role in understanding the spatial and temporal dynamics of hydrological fluxes of an ungauged watershed. The linkage between static (i.e. topography, soil properties and landuse) and dynamic (i.e. runoff, soil moisture and temperature) characteristics of a hillslope provides a new insight towards hillslope processes. Thus, two Lesser Himalayan hillslopes of Aglar watershed have been selected in two different landuses (grass-covered and agro-forested) and aspects (south and north). In this study, we analyzed the different hydrological fluxes i.e. rainfall, runoff, soil moisture and soil temperature along with the soil properties to get a holistic understanding of hillslope processes. We used the soil moisture dynamics and soil hydraulic conductivity as the major components to derive the hillslope hydrological connectivity. It was observed that the grassed (GA) hillslope generates less runoff than the agro-forested (AgF) hillslope as the upslope runoff of GA hillslope re-infiltrated in the middle portion due to higher soil hydraulic conductivity and surface resistance. Further, this explains that the runoff contributing areas are located at the lower and upper portions of hillslopes due to the presence of low soil hydraulic conductivity zones.  As both the hillslopes are dominated with Hortonian overland flow, the negative correlation was found between topographic indices (TWI) and soil moisture and positive correlation was noticed between soil hydraulic conductivity. Higher runoff (less infiltration) from AgF hillslope results in a higher negative correlation between TWI and soil moisture in comparison to GA hillslope. This results in a higher rate of change in soil temperature of GA hillslope than the AgF hillslope. After analyzing 40 rainfall events, it was concluded that a temperature drop of more than 2oC was recorded when the average rainfall intensity and event duration exceeds 7.5mm/hr and 7.5hr, respectively. The understanding of covariance of these hydrological fluxes will be used in the future to develop a hillslope-scale conceptual model.
How to promote Geography for Sustainability
Authors: Zhao Wenwu , Fu Bojie , Liu Yanxu
Published: March 2020

Human interactions with Earth systems have accelerated dramatically in recent decades. Human activities are altering the Earth system and exerting significant impacts on the environment, and undermining improvements in human wellbeing and poverty alleviation. In order to secure global prosperity and transform to global sustainability, United Nations launched the 17 Sustainable Development Goals (SDGs) of the 2030 Agenda for Sustainable Development in 2015. The goals include efforts to eradicate extreme poverty and to consolidate efforts to slow climate change and preserve our world environment. The process of implementing the SDGs has created new challenges for policy makers and for the scientific community. Half of the Sustainable Development Goals are related to environment and natural resources. Geographical Science is one of the most important KEY for sustainable development. Geographers have been conducting various experiments and modelling at multi-scales, and tried to identify the relationships between human activities and various earth surface processes, dwell on ecosystem processes and ecosystem services trade off at multi-scale, model the effects of human activity and earth systems, and try to figure out the possible sustainable solutions for regional, national and global developments. It’s time to launch a new journal focus on Geography and Sustainability for the world. That’s why, Faculty of Geographical Science (Beijing Normal University) start to publish the new journal: Geography and Sustainability. The new journal focus on: Geographical processes, Human-Environmental Systems, Ecosystem services and human being, Sustainable development, Geo-data and model for Sustainability. The new journal is also the office journal for IGU Commission on Geography for Future Earth: Coupled Human-Earth Systems for Sustainability.
The effects of anthropogenic heat fluxes on regional meteorology and air quality in typical city clusters of China
Authors: Xie Min , Wang Tijian , Shi Jie , Li Mengmeng , Gao Da , Zhan Chenchao
Published: March 2020

Anthropogenic heat (AH) can affect regional meteorology and air quality. The spatial distributions of AH fluxes in the typical city clusters of China are estimated. Moreover, in order to study their impacts on regional atmospheric environment, these heat fluxes are incorporated into the modified WRF/Chem with the seasonal and the diurnal variation. The modeling results show that AH fluxes over YRD and PRD have been growing in recent years. The high values of AH can reach 113.5 W/m2 in YRD and 60 W/m2 in PRD, respectively. AH fluxes can significantly change the urban meteorology. In YRD, 2-m air temperature (T2) increases by 1.6 °С in January and 1.4°С in July, the planetary boundary layer height (PBLH) rises up by 140m in January and 160m in July, and 10-m wind speed (W10) is intensified by 0.7 m/s in January and 0.5 m/s in July. More moisture can be transported to higher levels, and increase the accumulative precipitation by 15-30% in July of YRD. In PRD, T2 rises up by 1.1°С in January and over 0.5°С in July, the PBLH increases by 120m in January and 90m in July, W10 is enhanced over 0.35 m/s in January and 0.3 m/s in July, and the accumulative precipitation is intensified by 20-40% in July. These changes in meteorology can influence the distribution of air pollutants as well. Due to the increase of PBLH, surface wind speed and upward movement, the concentrations of primary air pollutants decrease near surface and increase at the upper layers over the cities. Chemical effects can play a significant role in ozone changes over the urban areas of YRD, so ozone concentrations increase at surface and decrease at the upper layers. In PRD cities, however, the chemical effects play a significant role in ozone changes in winter, while the vertical movement can be the dominant effect in summer. Thus, ozone concentrations in big cities increase in January, but decrease at the lower layers and increase at the upper layers in July. In all, AH fluxes should not be ignored in urban meteorology and air quality assessments.
Negative Effects of Shrinking Cities and the Dilemma of Their Sustainable Development
Authors: Zhou Guolei
Published: March 2020

Abstract: Urban shrinkage has become a global phenomenon, occurring all over the world. Faced with the reduction of population, shrinking cities will continue to lose the vitality of development, and it is difficult to achieve the past glory. How to realize the sustainable development of shrinking cities will become an important issue, which deserves our in-depth study. We will apply big data to analyze the spatiotemporal changes of the population of shrinking cities. Urban shrinkage will lead to a series of chain reactions, reflected in all aspects of social and economic development. Shops are closing down constantly, and there are very few visitors to the commercial streets at night. Industrial enterprises have moved to other places, and urban employment and financial income have declined sharply. The city's economy will face the risk of collapse. Consequently, the lack of maintenance of infrastructure and public service facilities, the decrease of residents' income and the decrease of residents' happiness lead to the lack of cohesion in urban society. The sustainable development of shrinking cities will face great difficulties. Therefore, we must be aware of the seriousness of this problem and take necessary actions to reduce the negative effects of urban shrinkage.

Key words: Shrinking cities, sustainable development, society, economy
Stable isotopic content of atmospheric precipitation and natural waters in the vicinity of Barentsburg (Svalbard) in 2016-2018.
Authors: Skakun Aleksandra , Ekaykin Alexey , Kozachek Anna , Tchikhachev Kirill , Vladimirova Diana , Verkulich Sergey
Published: March 2020

In 2016–2018, during Russian Arctic Expedition on Svalbard (RAE-S) we have collected the samples of atmospheric precipitation, terrestrial waters, snow and ice on West Spitsbergen island in the vicinity of Grønfjorden. The measurements of stable water isotope content (δ18O and δD) in the atmospheric precipitation collected in Barentsburg has allowed to draw the Local Meteoric Water Line and to analyze the relationship between the isotopic content and air temperature. Aside from this, the d-excess values in precipitation (dexc = δD – 8δ18O) was interpreted as a marker of the moisture source. This fact was confirmed by HYSPLIT modelling of atmospheric moisture. It has been demonstrated that the isotopic content of the surface waters (lakes and rivers on mountain glacier valleys) clearly points to the dominating type of feeding (atmospheric, ground) of these hydrological objects. We have discovered the small annual variability of the isotopic composition of Lake Kongress water during 2 years and defined the sources of water in its tributes: 13 of them have atmospheric source and 9 with ground source. In general, isotopic content of water in the vicinity of Grønfjorden (mean values are: δ18O = –10,3 ‰, δD = –72,5 ‰) is higher than in other regions of Svalbard.
Canal block location optimization for drained peatland restoration
Authors: Urzainqui Iñaki , Laurén Ari , Palviainen Marjo , Hökkä Hannu
Published: March 2020

Building canal or drain blocks is a powerful tool to raise the water table of a drained peatland and to enhance ecosystem restoration. When restoring large areas, the number of blocks becomes limited by the available resources, which raises the following question: in which exact positions should a given number of blocks be placed in order to maximize the water table raise? There is neither a simple nor an analytic answer. The water table response is a complex phenomenon that depends on several factors, such as the topology of the canal network, site topography, peat hydraulic properties, vegetation and meteorological conditions. We developed a new method to position the canal blocks which is based on the combination of a hydrological model and heuristic optimization algorithms. We applied this approach to a large drained peatland area (1100 km2) in Indonesia. Our solution consistently improved the performance of traditional block locating methods, indicating that drained peatland restoration can be made more effective at the same cost by selecting the positions of the blocks using a numerical approach.
Strain patterns of Sichuan and Yunnan, China from GPS data and comparison between seismic and geodetic moment release
Authors: Zhao Jingyang , Wu Yanqiang , Liang Hongbao , Du Kaifu
Published: March 2020

We processed data from ~600 GPS stations, covering the period 1999-2018, to provide new insights into the crustal motion and deformation of Sichuan and Yunnan, China. We used the derived velocity field to evaluate two-dimensional strain rate tensors, and mapped the main, maximum shear, dilatation, east-west and north-south strain rates.The spatial distribution of the main strain rate in the Sichuan-Yunnan region generally shows an orderly deflection. The minimum principal strain rate is northeastward in the west of the Sichuan-Yunnan block boundary, gradually deflects eastward and southeastward toward the east and south, and returns to the northeast direction until the southwestern edge of Sichuan-Yunnan. This reflects the complex tectonic dynamics background of the study area. The high value of the maximum shear strain rate is mainly distributed along the eastern boundary of the Sichuan-Yunnan block, especially near the Xianshuihe-Xiaojiang fault, where the maximum shear strain rate exceeds 4.0 × 10-8 / a. The area strain rate in the study region shows that the areas of compression and expansion are comparable, with weak tensions prevailing in the interior and compression in the marginal areas. The strain rate result also shows that the east-west strain rate component in the southern Sichuan-Yunnan is dominated by positive value, and the north is dominated by negative value. It indicates that the east-west deformation in the south of the Sichuan-Yunnan is dominated by expansion, and in the north is dominated by contraction. The north-south component strain rate shows that there is a significant positive high-value zone in and around the Xianshuihe fault zone, while southern Sichuan-Yunnan is a more significant negative-value zone, and the distribution of negative high-value zones is controlled by the south boundary of the Sichuan-Yunnan block. Based on the fault activity and focal mechanism data, the study area was divided into several seismic source zones. We translated the geodetic strain rates into rates of seismic moment release in each zone and compared them with earthquake catalog-based moment rates, to evaluate the potential of seismic activity of the region. The analysis shows the geodetic strain is completely released seismically for most of the study area. However, for the southern Yunnan，the geodesy-based moment rates are more than 2 times higher than the earthquake-based rates. This result indicates that at least a large earthquake may occur in southern Yunnan in the future.
Prediction of soil organic and inorganic carbon concentrations in Tunisian samples by mid-infrared reflectance spectroscopy using a French national library
Authors: Chevallier Tiphaine , Gomez Cécile , Moulin Patricia , Bouferra Imane , Hmaidi Kaouther , Arrouays Dominique , Jolivet Claudy , Barthès Bernard
Published: March 2020

Mid-Infrared Reflectance Spectroscopy (MIRS, 4000–400 cm-1) is being considered to provide accurate estimations of soil properties, including soil organic carbon (SOC) and soil inorganic carbon (SIC) contents. This has mainly been demonstrated when datasets used to build, validate and test the prediction model originate from the same area A, with similar geopedological conditions. The objective of this study was to analyze how MIRS performed when used to predict SOC and SIC contents, from a calibration database collected over a region A, to predict over a region B, where A and B have no common area and different soil and climate conditions. This study used a French MIRS soil dataset including 2178 soil samples to calibrate SIC and SOC prediction models with partial least squares regression (PLSR), and a Tunisian MIRS soil dataset including 96 soil samples to test them. Our results showed that using the French MIRS soil database i) SOC and SIC of French samples were successfully predicted, ii) SIC of Tunisian samples was also predicted successfully, iii) local calibration significantly improved SOC prediction of Tunisian samples and iv) prediction models seemed more robust for SIC than for SOC. So in future, MIRS might replace, or at least be considered as, a conventional physico-chemical analysis technique, especially when as exhaustive as possible calibration database will become available.
The westernmost Late Miocene-Pliocene volcanic activity in the Vardar Zone (North Macedonia) – geochronology, petrology and geochemistry of Pakoševo, Debrište and Šumovit Greben volcanic centers
Authors: Molnár Kata , Dibacto Stéphane , Lahitte Pierre , Temovski Marjan , Agostini Samuele , Benkó Zsolt , Ionescu Artur , Milevski Ivica , Palcsu László
Published: March 2020

Late Miocene to Pleistocene volcanism within the Vardar zone (North Macedonia) covers a large area, has a wide range in composition and it is largely connected to the tectonic evolution of the South Balkan extensional system, the northern part of the Aegean extensional regime. The scattered potassic to ultrapotassic volcanism developed south from the Scutari-Peć fault zone since 6.57 Ma [1]. The focus of this study is on three volcanic centers located on deep structures or thrust faults along the western part of the Vardar zone, for which there is none to very little geochronological and geochemical data available. Pakoševo and Debrište localities are represented as small remnants of lava flows cropping out at the southern edge of Skopje basin and at the western edge of Tikveš basin, respectively. Šumovit Greben center is considered as part of the Kožuf-Kozjak/Voras massif (6.5-1.8 Ma [1]), and it is located on its westernmost side, at the southern edge of Mariovo basin, which is largely comprised of volcanoclastic sediments. Here we present new eruption ages applying the unspiked Cassignol-Gillot K-Ar technique on groundmass, petrological and geochemical data, supplemented with Sr and Nd isotopes to complement and better understand the Neogene-Quaternary volcanism in the region. Obtaining the eruption ages of these volcanic centers could also help to better constrain the evolution of the sedimentary basins. All of the three centers belong to the shoshonitic series based on their elevated K-content. The oldest center amongst these three localities, as well as other Late Miocene centers within the region, is the trachyandesitic Debrište, which formed at ca. 8.1 Ma, and exhibits the highest Nd isotopic ratios (0.512441-0.512535). The trachybasaltic Pakoševo center formed at ca. 3.8 Ma and, based on its Nd isotopic ratio (0.512260), represents the strongest sign of crustal contamination. The rhyolitic Šumovit Greben center is a composite volcanic structure formed at ca. 3.0-2.7 Ma. Its youngest eruption unit has a slightly larger Nd isotopic ratio (0.512382), representing a less evolved magma at the end of its activity.

This research was funded by the GINOP-2.3.2-15-2016-00009 ‘ICER’ project, the French-Hungarian Cooperation Program TÉT-FR-2018-00018 and the HORIZON 2020 grant N 676564.

References:

[1] Yanev et al., 2008 – Mineralogy and Petrology, 94(1-2), 45-60.
Spatial control of carbon dynamics in soil by microbial decomposer communities
Authors: Pagel Holger , Kriesche Björn , Uksa Marie , Poll Christian , Kandeler Ellen , Schmidt Volker , Streck Thilo
Published: March 2020

Trait-based models have improved the understanding and prediction of soil organic matter dynamics in terrestrial ecosystems. Microscopic observations and pore scale models are now increasingly used to quantify and elucidate the effects of soil heterogeneity on microbial processes. Combining both approaches provides a promising way to accurately capture spatial microbial-physicochemical interactions and to predict overall system behavior. The present study aims to quantify controls on carbon (C) turnover in soil due to the mm-scale spatial distribution of microbial decomposer communities in soil. A new spatially explicit trait-based model (SpatC) has been developed that captures the combined dynamics of microbes and soil organic matter (SOM) by taking into account microbial life-history traits and SOM accessibility. Samples of spatial distributions of microbes at µm-scale resolution were generated using a spatial statistical model based on Log Gaussian Cox Processes which was originally used to analyze distributions of bacterial cells in soil thin sections. These µm-scale distribution patterns were then aggregated to derive distributions of microorganisms at mm-scale. We performed Monte-Carlo simulations with microbial distributions that differ in mm-scale spatial heterogeneity and functional community composition (oligotrophs, copiotrophs and copiotrophic cheaters). Our modelling approach revealed that the spatial distribution of soil microorganisms triggers spatiotemporal patterns of C utilization and microbial succession. Only strong spatial clustering of decomposer communities induces a diffusion limitation of the substrate supply on the microhabitat scale, which significantly reduces the total decomposition of C compounds and the overall microbial growth. However, decomposer communities act as functionally redundant microbial guilds with only slight changes in C utilization. The combined statistical and process-based modelling approach derives distribution patterns of microorganisms at the mm-scale from microbial biogeography at microhabitat scale (µm) and quantifies the emergent macroscopic (cm) microbial and C dynamics. Thus, it effectively links observable process dynamics to the spatial control by microbial communities. Our study highlights a powerful approach that can provide further insights into the biological control of soil organic matter turnover.
Does carbon allocation determine the timing of autumn leaf senescence in deciduous trees?
Authors: Campioli Matteo , Mariën Bertold , Dox Inge
Published: March 2020

Carbon allocation is a crucial process in plants and ecosystems. However, does carbon allocation also impact plant phenology, in particular during autumn? Elucidation of autumn tree phenology is essential as autumn leaf senescence affects leaf nutrient resorption, next year tree growth potential and the seasonal exchange of energy and material (e.g. CO2, H2O, VOCs) between vegetation canopy and the atmosphere. Environmental manipulative experiments clearly show that the onset of leaf senescence in deciduous trees is not only controlled by internal cues but also that is crucially affected by environmental factors. Yet, we have not understood which are the environmental drivers of leaf senescence onset as, for example, day length, temperature, water and nutrient availability, all showed to impact autumn phenology in a given species, sites, years and experimental setting. The knowledge gap around the environmental drivers of leaf senescence might be due to the fact that, up to date, we have investigated autumn dynamics of leaves (carbon sources) but overlooked the autumn activity of branches, stem and roots (carbon sink). Are leaves in autumn needed for the tree if no sinks are active? In other words, is leaf senescence triggered by the cessation of tree growth in autumn? In more detailed, we expected that: (i) in the absence of growth-limiting environmental conditions, tree growth cessation directly controls leaf-senescence onset, and (ii) in the presence of growth-limiting conditions, photoperiod controls leaf-senescence onset – this prevents trees from starting to senesce too early. These hypotheses have been the topic of three years of monitoring and experimental campaigns in different deciduous species and European locations within the ERC project LEAF-FALL, and of ancillary data analysis work. The presentation aims to show key results and the most novel aspect of this line of research.
Short-term precursors of the M=5.5-7.2 earthquakes in South California revealed from the simulated stress-strain state patterns
Authors: Gokhberg Mikhail , Bondur Valery , Garagash Igor , Alekseev Dmitry
Published: March 2020

Since 2009, the stress-strain state of the earth’s crust in South California region is being tracked utilizing the geomechanical model accounting for all the current seismicity. Every new earthquake is treated as a new defect in the Earth's crust, causing the stress-strain state redistribution. Through the continuous stress-strain state update, we found that all the significant earthquakes in the area, including those with M ~ 7 in 2010 and 2019, had been preceded by the anomalies in the strength parameter
Soil cover development in the coastal zones of disappearing lakes
Authors: Słowiński Michał , Kruczkowska Bogusława , Jonczak Jerzy , Słowińska Sandra , Bartczak Arkadiusz , Kramkowski Mateusz , Uzarowicz Łukasz , Tyszkowski Sebastian
Published: March 2020

An increased rate of shallow lakes overgrowth is a commonly observed process in the European lowlands. The transition period from the lake to the peatland state is the most productive phase in the whole evolutionary history of a lake. In this study, we analyze the influence of environmental changes in the Lake Rakutowskie wetlands complex (central Poland) and water level fluctuations on soil cover modifications in the immediate vicinity of the lake.  Multidisciplinary research was conducted in a transect consisting of eight soil profiles. The transformation of soil cover was reconstructed on the basis of detailed studies of soil characteristics, water level fluctuations, radiocarbon dating, etc. Significant acceleration of the lake decline rate is associated not only with natural processes but predominantly with anthropic pressure. The obtained C14dates indicate a very rapid disappearance of the lake. Taking into account the causative factors, the lake will most likely disappear in the next hundreds of years. The contemporary surface of Lake Rakutowskie is several times smaller than in the past, and this is an effect of the influence of natural and anthropogenic factors. Former fibric materials have been transformed into sapric and hemic ones as an effect of soil exsiccation. The next (and last) step in the degradation of organic soils is muck formation. Along with the progressive dehydration and mineralization of organic soils, its physical and chemical properties have deteriorated, which is visible e.g. in soil structure and elemental content, especially TOC and TN. With the disappearance of the lake, larger adjacent areas are subjected to gradual degradation, leading directly to plant cover changes and irreparable landscape modifications.

 
Retention potential analysis of river restoration and floodplain measures in different catchments of Bavaria, Germany
Authors: Neumayer Michael , Teschemacher Sonja , Merk Fabian , Disse Markus
Published: March 2020

Nature-based solutions are an important component of integrated flood mitigation strategies for improving both the protection against hazardous flood events and the ecological conditions of river-floodplain systems. In order to be able to take these types of measures into account in upcoming flood management decisions, it must be possible to reliably estimate their effects on flood events. Therefore, this study focuses on a more general view on the catchment dependent contribution of combined river and floodplain restoration measures to the strengthening of river retention and flood protection. Furthermore, the importance of considering site-specific circumstances (e.g., the superposition of the flood waves of the main river and its tributaries), is evaluated.

The study is based on five investigation areas in Bavaria (Germany) with various topographic properties and different spatial scales (~ 90 – 560 km2). For each catchment, a physically based hydrological model (WaSiM) was coupled with the two-dimensional hydrodynamic model HYDRO_AS-2D by means of direct and diffuse inflow boundary conditions. Five flood events with various rainfall characteristics (advective/convective) and different return periods (5, 20 and 100 years) were generated with WaSiM. The holistic restoration scenarios are implemented by catchment dependent modifications of river channels and floodplains. As the aim of this study is to analyze the maximum possible efficiency of the restoration scenarios, it is assumed that almost the entire floodplain is available for the implementation of these measures. Highly restricted areas (e.g., settlement & industrial areas, important infrastructure) are excluded from this assumption. First results show that the peak discharge attenuations resulting from the restoration measures are exemplarily dependent on the characteristics of the floodplains (e.g., slope and extent) and the volumes of the flood events. It could be shown that the largest peak discharge attenuations (up to 28 %) and retardation (up to 8 h) occur in catchments with relatively flat and wide floodplains in combination with comparatively small flood volumes. Furthermore, the effectiveness of these measures can be considerably affected by local superposition effects with incoming tributaries. These effects can have site and event specific positive or negative impacts on the peak discharges and may not be neglected when planning restoration measures.

Based on these investigations, it is possible to evaluate if catchments are likely to be suitable for river and floodplain restoration in the course of flood management decisions. However, the effectiveness of the measures is always influenced by a combination of many area-specific factors that can only be predicted to a limited extent and therefore requires the modelling of an area.
The relationship between evolution of Frontal Ridge growth and sediment-routing system in the developing marine accretionary prism in offshore Southwest Taiwan
Authors: Liu Ting-Yi , Yang Kenn-Ming , Lin Liang-Fu , Liu Char-Shine
Published: March 2020

Sediment-routing system in a developing marine accretionary prism is highly related to the thrusting and the accompanied fold structures. The main purpose of this study is to investigate how the thrust fault growth had spatially and temporally affected sediment transport paths in the frontal part of the developing accretionary prism in offshore Southwest Taiwan. This study attempts to reveal the lateral change in dipping angle of and displacement along thrust fault and the accompanied variation in trend of the submarine channels by interpreting a grid of seismic section.

 

The Frontal Ridge is the outmost topographic high in the frontal part of the accretionary prism in offshore Southwest Taiwan and has been regarded as the resultant anticlinal fold caused by westward thrusting. The major structural trend of the ridge is NW-SE and the fold tightness with the displacement along the fold-forming thrust decreases southeastward. Beneath the backlimb of the fold, basal boundary of the growth strata can be defined by a major unconformity and the overlying strata wedging westward to the ridge. The backlimb dipping angle is smaller than that of the thrust ramp. While narrow channels appear in the growth strata and parallel to the strike of fault, a wide submarine fan can be observed in the pre-growth strata. In the lower part of the growth strata, upstream of the channels is characterized by several narrow, concentrated and deep-cutting channels younging toward the east. On the other hand, downstream of the narrow channels appears as the distributed channels, which are overlain by the younger narrow and concentrated channels that are running along a synclinal axis in the upper part of the growth strata.

 

We propose that the Frontal Ridge is a manifestation of a shear fault-bend fold in the subsurface and the ridge uplifted first from its northwestern end and propagated toward the southeast. The southeastward propagating fold had strongly affected sediment-routing path and deposition. At each stage, the active thrusting and accompanied piggy-back structure offered the loci for narrow and deep-cutting channels in the upstream areas. On the other hand, in the downstream areas, the channels ran far from pre-existing thrust front and spread out into distributed channels. When the frontal thrust continued to propagate to the southeastern end, the younger channels developed and migrated gradually to be restricted in the synclinal axial area. Meantime, the distributed channels in the original downstream areas would become a part of the folded pre-growth strata underneath the ridge.

 

Key words: Sediment-routing system, accretionary prism, syn-tectonic deposition, Southwest Taiwan
Detection of the deep cavern at the Felsopeteny, Hungary site using seismic ambient noise data
Authors: Kristekova Miriam , Kristek Jozef , Moczo Peter , Labak Peter
Published: March 2020

Nuclear explosions are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Obviously, the CTBT needs robust and comprehensive verification tools to make sure that no nuclear explosion goes undetected. The detection of underground cavity due to nuclear explosions is a primary task for an on-site inspection (OSI) and resonance seismometry. Recently we have developed the finite-frequency-range spectral-power method that makes it possible to use seismic ambient noise recorded at the free surface above an underground cavity for localizing it. In this contribution we present results of application of the method to data recorded at a site of the Great Cavern near Felsopeteny, Hungary.

CTBTO performed several active and passive seismic measurements at the free surface above the Great Cavern in September 2019. Seismic ambient noise was recorded one week continuously at almost 50 stations with interstation distance around 50 m covering area 400 x 400 m.

The oval shaped cavern with a diameter of 28 m located 70 m below the surface was discovered within a clay mine in N-Hungary. The deep basement is composed of Triassic limestone, the cavern is in the overlying Oligocene sandstone formation. As a result of hydrothermal activity in the Pleistocene a cave formed in the limestone which may have collapsed over time. The opening of the deep part of the cave influenced the overlying sandstone formation but the collapse did not reach the surface.

We present the procedure of pre-processing and identification of a position of the cavern based on the recorded seismic ambient noise. We checked robustness of the obtained results. The results demonstrate potential of our methodology for the OSI purposes.
Classification of Mini-catchment typologies for analyzing dominant controls of nutrient dynamic in three Nordic countries
Authors: Hashemi Fatemeh , Pohle Ina , Tornbjerg Henrik , Kyllmar Katarina , Marttila Hannu , Lepistö Ahti , Kronvang Brian
Published: March 2020

Selection of non-point nutrient pollution management and mitigation options in catchments requires in-depth understanding of both spatial and temporal controlling aspects on nutrient dynamics for covering a diversity of factors controlling nutrient transfer to surface waters. Such an understanding can be obtained by analyzing the hysteresis behaviors and export regime in concentration-discharge (c-Q) relationships from the monitoring stations in smaller streams. 
A classification scheme developed by Pohle et al. (2019), including nine different c-Q relationships classes were defined as a combination of export behavior (dilution, neutral, enrichment) and rotational pattern of the hysteresis (clock-wise, no rotation, anti-clockwise). To perform this, the export behavior was assessed based on the theoretical c-Q relationships by checking whether concentrations decrease, increase or do not change with discharge (Mann-Kendall test). The rotational pattern was also determined by comparing concentrations at the rising and the falling limb of the hydrograph (Kruskal-Wallis test).
The classification has been applied to a 8 years record (2010-2017) of daily discharge and discrete nutrient concentration  data from 88 small streams including forms such as - Nitrate, Organic N, Dissolved Reactive Phosphorus and Particulate P  from Denmark, Sweden and Finland. The streams drains catchments with a size ranging from 0.1 km² – 65 km². Additionally similarity in types of c-Q relationships were investigated by multivariate analysis for N and P forms  considering effects of land use, climate, soil type and the size of the catchments  . 
The dilution behavior of the catchments might dominantly be related to arable catchments with low groundwater inputs and with a good direct contact from root zone to the stream (e.g. through tile drains for N) and macropore or surface runoff for P. The constant behavior of the catchments might dominantly be related to dominance of groundwater fed streams in arable or natural catchments and the enrichment behavior might dominantly be found in catchments influenced by point source discharges of nutrients.
This kind of catchments classification can be used for planning of optimal sampling frequencies in monitoring programs, cost-optimal dosing of mitigation options in catchments and inform about expected inertias in catchment responses to management. 
Wave-mean flow interaction, forced triads, and recharge-discharge Processes as noncanonical Hamiltonian Systems
Authors: Blender Richard , Fregin Joscha
Published: March 2020

We consider recharge-discharge processes in a forced wave-mean flow interaction model and in a forced Rossby wave triad. Such processes are common in atmospheric dynamics and are typically modelled by nonlinear oscillators, for example for mid-latitude storms by Ambaum and Novak (2013) and for convective cycles by Yano and Plant (2012). A similar behaviour can be seen in the simulation of a forced wave number triad by Lynch (2009). Here we construct noncanonical Hamiltonian and Nambu representations in three-dimensional phase space for available and prescribed conservation laws during the recharge and discharge regimes. Divergence in phase space is modelled by a pre-factor. The approach allows the design of conservative and forced dynamical systems.
The impact of the Westerlies on the PBL growth and land surface energy balance on the north of the central Himalaya
Authors: Chen Xuelong , Lai Yue , Ma Yaoming
Published: March 2020

The spatial-temporal structure of the Planetary Boundary Layer (PBL) over mountainous areas can be strongly modified by topography. The PBL over the mountainous terrain of the Tibetan Plateau (TP) is more complex than that observed over its flat areas. To date, there have been no detailed analyses which have taken into account the topography effects exerted on PBL growth over the Tibetan Plateau (TP). A clear understanding of the processes involved in the PBL growth and depth over the TP’s mountainous areas is therefore long overdue.
The PBL in the Himalayan region of the Tibetan Plateau (TP) is important to the study of interaction between the area’s topography and synoptic circulation. This study used radiosonde, in-situ measurements and ECMWF ERA5 reanalysis dataset to investigate the vertical structure of the PBL and the land surface energy balance in the Rongbuk Valley on the north of the central Himalaya, and their association with the Westerlies, which control the climate of the Himalaya in winters. Measurements show that the altitude of the PBL’s top in November was the highest of three intensive observation periods (i.e., June, August and November). The PBLs in November appeared to have been influenced by the Westerlies which prevails in this region during the non-monsoon season. We discovered that the deep PBLs seen in November correlate with the downward transmission of the Westerlies to the valley floor (DTWTV). It was found that DTWTV happened in the direction of southwest when the synoptic wind above the valley ridges height blow from southwest, which is parallel to the valley axis. DTWTV happened in the direction of southwest promotes a stronger near-surface wind, smaller aerodynamic resistance, and larger sensible heat flux, which cause PBLs grow high.