bluuebunny/crossref_metadata_2025 huggingface dataset:
An improved rule-based approach to map burned areas using Landsat and Sentinel-2 images
Authors: Kanaropoulos Symeon , Koutsias Nikos
Published: March 2020

This study presents an improvement of an old rule-based semi-automatic method to map burned areas by using multi-temporal Landsat and Seninel-2 images. The rule-based approach consists of a set of rules developed based on spectral properties of burned areas as compared to the pre-fire unburned vegetation and to the spectral signatures of other land cover types found in post-fire satellite scene. Actually, the spectral properties based on which the rules have been developed are presented in two graphs, one that corresponds to spectral signatures plots and the second that corresponds to the histogram data plots. The spectral patterns based on which the rule-based approach has been developed are not always the same. For example, depending on the type of the fire-affected vegetation (e.g. dry vegetation instead of green) the spectral pattern of the SWIR channel that correspond to channel 7 in Landsat 4-7 and 8 is not valid. Instead, there is a similar spectral behaviour but in the SWIR channel that correspond to channel 5 in Landsat 4-7, or channel 6 in Landsat 8. Additionally, the threshold value of 0.10-0.25 of the second rule seems not to be sufficient to cover all variability since there are cases that this value should be higher. Two characteristic examples of the insufficiencies found on the old-rules are concerned in the current analysis, one that presents limitations concerning the rule 5 (Serifos) and one that represents limitations concerning the rule 2 (Portugal). In this study we present a further improvement of the method and also its application to several cases spread out in Greek islands using both Landsat and Sentinel-2 images.
Robust retrieval of surface soil moisture across wide-ranging incidence angles over short crops: for application to NI-SAR
Authors: Kim Seungbum , Liao Tienhao
Published: March 2020

We present our ongoing efforts to deliver surface soil moisture information at agricultural field scales using airborne or satellite synthetic aperture radar (SAR) data through the development and inversion of physical models for forward radar scattering from vegetation surfaces. While the past successful results were validated at 40-deg incidence angle for the Soil Moisture Active passive mission, the current work extends the incidence angle range from 30 to 50 degs so that the algorithm may apply to the future L-band NASA-ISRO SAR (NI-SAR) mission. NI-SAR aims at providing global soil moisture data at 200m resolution every 6 days.

The soil moisture retrievals were validated over agriculture sites in Canadian Prairies using L-band airborne SAR data, where the fields experienced entire crop growth stages and two cycles of wetting and drydowns. The forward models were developed over NI-SAR’s incidence angle range of 30 to 50 degs for individual crops.

The estimates are accurate to unbiased rmse of 0.053, 0.058 and 0.047 m3/m3 in volumetric water content for soybean, wheat, and pasture fields respectively over diverse conditions of vegetation growth and soil wetness. Surface roughness and vegetation amount were retrieved simultaneous to the soil moisture solutions. The roughness estimates are realistic.

There was no significant effect of the local incidence angle on the retrieval performance, most likely because the path length of the radar wave through the vegetation (and therefore extinction of the soil moisture signal) did not vary much with incidence angle. The results are encouraging for successful soil moisture mapping for the NI-SAR mission.
Bare-earth DEM Generation in Urban Areas Based on a Machine Learning Method
Authors: Liu Yinxue , Bates Paul , Neal Jeffery , Yamazaki Dai
Published: March 2020

Precise representation of global terrain is of great significance for estimating global flood risk. As the most vulnerable areas to flooding, urban areas need GDEMs of high quality. However, current Global Digital Elevation Models (GDEMs) are all Digital Surface Models (DSMs) in urban areas, which will cause substantial blockages of flow pathways within flood inundation models. By taking GPS and LIDAR data as terrain observations, errors of popular GDEMs (including SRTM 1” void-filled version DEM - SRTM, Multi-Error-Removed Improved-Terrain DEM - MERIT and TanDEM-X 3” resolution DEM -TDM3) were analysed in seven varied types of cities. It was found that the RMSE of GDEMs errors are in the range of 2.3 m – 7.9 m, and that MERIT and TDM3 both outperformed SRTM. The error comparison between MERIT and TDM3 showed that the most accurate model varied among the studied cities. Generally, error of TDM3 is slightly lower than MERIT, but TDM3 has more extreme errors (absolute value exceeds 15 m). For cities which have experienced rapid development in the past decade, the RMSE of MERIT is lower than that of TDM3, which is mainly caused by the acquisition time difference between these two models. A machine learning method was adopted to estimate MERIT error. Night Time Light, world population density data, Openstreetmap building data, slope, elevation and neighbourhood elevation values from widely available datasets, comprising 14 factors in total, were used in the regression. Models were trained based on single city and combinations of cities, respectively, and then used to estimate error in a target city. By this approach, the RMSE of corrected MERIT can decline by up to 75% with target city trained model, though less significant a reduction of 35% -68% was shown in the combined model with target city excluded in the training data. Further validation via flood simulation showed improvements in terms of both flood extent and inundation depth by the corrected MERIT over the original MERIT, with a validation in small sized city. However, the corrected MERIT was not as good as TDM3 in this case. This method has the potential to generate a better bare-earth global DEM in urban areas, but the sensitive level about the model extrapolative application needs investigation in more study sites.
Study of nitrogen compounds in different atmospheric compartments
Authors: Ghaffar Christelle , Brissy Maxence , Dieme Binta , Lerembourg Martin , Brigante Marcello , Amato Pierre
Published: March 2020

Nitrogen molecules are present in the atmosphere also as inorganic ions (ammonium, nitrate…) and organic (peptides and proteins). Nowadays, there is still poor knowledge concerning the sources and fate of proteins and peptides in the atmosphere. In a larger context aiming at exploring microbial communities’ functioning in the atmosphere, the goal of this study is to examine the atmospheric proteome (peptide and protein contents, sequence, size distribution, biological functions) in the different atmospheric compartment (aerosols, cloud and rain waters).

Aerosols, cloud water and rain samples were collected at remote places nearby Clermont – Ferrand city (France) and from the Mountain “Puy de Dôme” (1465 m asl). Cloud droplet impactors and high volume impingers were used for allowing immediate fixation of the samples, by collecting within a protease inhibitor solution. Samples were filtered (0.22 µm porosity) and the proteins from water were digested using trypsin. The peptides were purified by solid phase extraction (SPE) method, concentrated by lyophilisation and analysed by LC – HRMS and MS². Preliminary results indicate the recurrence of certain small peptides in particular. Some of these most frequently observed peptides were selected as models for photochemical experiments. Briefly, these small peptides were irradiated under solar simulated conditions and products were identified by IC – MS, to assess the impact of such processes on the chemical composition of the atmosphere.

The next step will consist in analysing our observations along with chemical and biological parameters such as biodiversity, transcriptomic profiles, in order to better understand the interaction between microorganisms and atmosphere processes.
Temporal changes of the radiocesium activity concentration in river bottom sediment and suspended sediment in Eastern Japan
Authors: Onda Yuichi , Tang Chen , Gao Xiang , Takeuchi Yukio , Taniguchi Keisuke , Kurihara Momo , Hirose Katsumi
Published: March 2020

We examined the temporal trend of Cs-137 concentration of river sediment and suspended sediment in Eastern Japan areas from September 2011 to January 2017. We used 716 monitoring data by the Ministry of the Environment from 461 sites and applied particle size correction to eliminate the influence of changes in particle size distribution in the concentration of Cs-137.　Also, in some locations, we also compared the activity concentration of suspended sediment and dissolved water in Cs-137 and compared.    The results showed that Cs-137 concentration decreased through the study period in most sites, and the average declining, λ, is about 0.168 in the 2013-2018 period. In some sites increasing trend or larger rate of decline were found, but these locations are limited to lower contaminated catchments (less than 50k Bq/m2). The particle size corrected Kd value of the bottom sediment (Kd ac) shows around 10-4 to 10-5 Kg/L, but varied significantly where the initial catchment inventories are less than 50 kBq/m2. In most sites,  Cs-137 concentration on the particle size corrected Suspended sediment and bottom sediment show similar values, except for some specific sites (such as near the coast, etc).  These data imply that the activity concentration of dissolved Cs is important to control the rate and processes of interaction of dissolved radionuclides with the bottom sediment interface layer in the river environment affected by the Fukushima fallout.
Rossby wave packets associated with extreme precipitation events over Northern-Italy
Authors: Grazzini Federico , Fragkoulidis Georgios , Teubler Franziska , Wirth Volkmar , Craig George
Published: March 2020

Several studies on extreme precipitation events (EPEs) in the alpine area reported, as the main triggering factor, a meridionally elongated upper-level trough (i.e., a breaking Rossby wave) as part of an incoming Rossby wave packet (RWP). In this work, we investigate a vast number of EPEs occurring between 1979 and 2015 in northern-central Italy. The EPEs are subdivided into three categories (Cat1, Cat2, Cat3) according to thermodynamic conditions over the affected region. The three categories do not only differ locally but also in the evolution of precursor RWPs. These differences cannot be solely explained by the apparent seasonality of the flow; therefore, the relevant physical processes in the RWP propagation of each case are further investigated. In particular, we show that RWPs associated with the strongest EPEs, namely the ones falling in Cat2, undergo a substantial amplification over the western N. Atlantic due to anomalous ridge-building two days before the event; arguably due to diabatic heating sources. This type of development induces a downstream trough which is highly effective in focusing water vapour transport towards the main orographic barriers of the Apennines and the Alps. Finally, we identify an increasing trend of water vapour transport over the western N. Atlantic which is likely associated with the observed increase in Cat2 and Cat3 events
Isotopic studies on ore potential granitoid rocks in the Häme belt, Finland
Authors: Kurhila Matti , Tiainen Markku , Huhma Hannu , Mäkitie Hannu
Published: March 2020

The Häme belt in southwestern Finland hosts several types of ore formations. Among others, Cu, Au, W, Li and La mineralizations have been identified. These mineralizations are linked with various types of granitoid rocks within the Paleoproterozoic Svecofennian bedrock. We have studied the granitoids and equivalent hypabyssal rocks by whole-rock geochemistry, U-Pb zircon geochronology and Sm-Nd isotope analysis. Geochemically, the granitoids show a wide range from adakitic to arc-type, implying that they had different source environments. New age data show that different types of granitoids (tonalitic, leucogranitic, granodioritic etc.) were emplaced simultaneously: the samples have ages from 1888 Ma to 1883 Ma and are coeval within the error limits. Nd isotopic results show slightly depleted compositions with initial epsilon values around +1, in line with most of the previously published data. An exception is the Cu-Au bearing Arolanmäki granite, which indicates a juvenile origin with an initial epsilon value of +3.2.

Overall the sources of granitoid magmatism vary considerably, and the overlapping ages indicate either a very rapid sequence or a simultaneous existence of varying types of magmatism. The ages coincide with the main stage of the Svecofenniean orogeny in the area. Later tectonic and hydrothermal activity is demonstrated by <1.80 Ga monazite and titanite ages as well as pegmatites. The granitoid magmatism of the Häme belt is related to several types of ore forming processes. The 1.88 Ga granitoids are hosting Cu-Au and W-Au-deposits, some of them interpreted as porphyric type deposits. The 1.80 Ga pegmatites include several LCT pegmatites hosting Li-deposits. The orogenic gold deposist of the Jokisivu-type in Häme belt have been interpreted to be controlled by the shear zones related to the 1.80 Ga granitoid magmatism. 
Nowcasting lightning during RELAMPAGO
Authors: Ruzanski Evan , Chandrasekar Venkatachalam , Arias Ivan
Published: March 2020

The Remote Sensing of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations (RELAMPAGO) international field campaign occurred June 1, 2018, to April 30, 2019. This campaign was comprised of more than 150 scientists from 10 organizations. Data was collected to investigate different phases of the life cycle of thunderstorms that occur in Argentina to better understand the physical mechanisms that cause the initiation and growth of organized convective systems in some of the most intense storms on the planet. The main focus of the project was to develop new conceptual models for forecasting extreme weather events that will hopefully lead to reductions in future loss of life and property.

This presentation shows the performance of a recently developed model for estimating ice mass aloft, a key component in the atmospheric electrification process, and a method for nowcasting lightning activity using C-band weather radar and Global Lightning Dataset (GLD360) data from RELAMPAGO. This nowcasting method uses a grid-based approach to make specific forecasts of lightning in space and time. The method estimates ice mass aloft in the region where electrification occurs using a numerical optimization approach to essentially reframe a simplified bulk microphysical model into a completely data-driven model. Previous results using WSR-88D S-band radar data in the United States showed that using this model significantly improved nowcasts of first-flash lightning occurrence versus the traditional weather radar-based ice mass estimator as well as using lightning flash-rate density directly.
Effects of climate change on runoff variability in mid-latitude montane basins
Authors: Langhammer Jakub , Bernsteinová Jana
Published: March 2020

The study analyzed long-term changes of runoff variability of headwater montane basins in Central Europe as a response to the effects of climate change and modifications to the environment.

The aim was to compare the patterns of variability of the indicators of hydrologic alteration, derived from long-term time series of daily discharge observations in montane basins with the recent premises of climate change effects on surface runoff dynamics in the Central Europe region. In particular, there were tested the following assumptions: (i) recent climate warming will result in the shifts of the runoff seasonality and distribution and in (ii) higher variability of runoff, displayed by a higher frequency of floods and droughts, while (iii) the indicators of runoff balance will remain without significant changes.

These hypotheses were tested in a set of 8 unregulated montane catchments, spreading over the border mountain ranges of the Czech Republic - the Šumava Mountains (Bohemian Forest), Krušné hory (Ore Mountains), Jizera Mountains, Krkonoše (Giant Mountains), Orlické Mountains and Beskydy Mountains. All basins are of comparable size (30-90 km2), and without significant hydrological regulations. Their west-east geographical distribution allows for tracking the potential effects of the gradient of climate continentality in the Central European region. The uninterrupted time series of daily discharge observations from 1953 to 2018 were used for the analyses at the gauging stations. 

We focused on indicators that reflect the aspects of the runoff regime, that are likely to be affected by the assumed effects of the changing climate. Variety of time series analysis and statistical techniques was applied, including the set of 33 Indicators of hydrologic alteration (IHA), 34 Indicators of Environmental flow components, frequency and distribution of the peak an low flows, statistical testing of significance of changes using Mann-Kendall test, breakpoint analysis, analysis of deficit and surplus volumes and homogeneity testing using Buishand, Petitt and SNHT tests.

The study has identified the significant shifts in the hydrological response of montane basins that are apparent in seasonality, balance, and variability of discharge. The analyses proved (i) changes in runoff response reflecting the timing of the observed changes in air temperatures, (ii) the shift of spring snowmelts towards earlier spring and a corresponding decline of may flows, occurring in all of the investigated regions, (iii) diverging trends of high flows across the basins, (iv) changing dynamics of rainfall-runoff response (v) better sensitivity of indicators, reflecting low magnitude events and (vi) decline of low flow indicators across the basins.
Channelized Antarctic ice shelf melting from high-resolution remote sensing
Authors: Lhermitte Stef , Nederend Jeffrey , Wouters Bert
Published: March 2020

Antarctic mass loss is the largest source of uncertainty in current sea level rise projections. Ice shelf instability plays a key role in this uncertainty as ice shelves are the floating gatekeepers that surround 75% of Antarctica’s coastline and that buttress the contribution of grounded ice to sea level rise. Although basal melting has been identified as one of the key processes for ice shelf instability, the quantitative understanding of this process and how much, how fast it weakens ice shelves is limited as it is determined by fine scale processes (e.g. channelized basal melting) that until recently were difficult to quantify. The recent availability of high-resolution, multi-source satellite imagery (e.g. stereoscopic DEMs from the Reference Elevation Model of Antarctica (REMA) or swath-processing of Cryosat-2), however, offers the opportunity to quantify the role of channelized melting on ice shelf instability across Antarctica.

In this study, we use REMA, Cryosat-2 and IceBridge elevation data to develop high-resolution indicators of basal melt across some major Antarctic ice shelves (Dotson, Pine Island, Larsen C). The methodology consists of processing time series of high-resolution REMA strips in a Lagrangian framework while accounting for tilt and tide corrections.

Comparison of different approaches (e.g. simplified REMA-only approach; combined REMA-Cryosat-2 approach, combined REMA-IceBridge approach) shows that the simplified approach can be applied easily to develop Antarctic wide estimates of basal melting across Antarctica, while the combined REMA-Cryosat-2 shows the highest accuracy. Results of this study, finally, show the potential of using REMA for developing high resolution basal melt products across Antarctica and providing insight in the spatial variability of basal melting due to channelized melting.
Forecasting alpine glacier evolution at the seasonal/multiannual scale
Authors: Chiarle Marta , Paranunzio Roberta , Nigrelli Guido , Mortara Giovanni , Terzago Silvia , von Hardenberg Jost , Cardinali Chiara
Published: March 2020

For application purposes (in particular water resources management and planning) it is crucial to rely on accurate predictions of the evolution of glaciers on short time scales (from seasonal to multi-annual).

This is one of the aims of the MEDSCOPE project in the framework of the ERA4CS initiative: seasonal-to-decadal climate forecasts, produced and downscaled by the project, are used to estimate the evolution of glaciers in selected areas of the Western Italian Alps.

For this purpose, empirical glacier models have been calibrated with historical observational data of glacier front fluctuation and mass balance for five glaciers, characterized by different morphology and topoclimatic setting, in the Western Italian Alps. The models will be forced with the seasonal, downscaled forecasts, in order to assess the added value provided by MEDSCOPE to climate services for water management.
Presenting hydrological and data driven flood simulation-prediction methods to develop a decision-making model
Authors: Zare Mohammad , Schumann Guy , Teferle Felix Norman , Matgen Patrick , Bates Paul D.
Published: March 2020

Flooding is the number one natural disaster in terms of insured and uninsured losses annually. The development of reliable methods for flood simulation have greatly improved our ability to predict floods thereby reducing damages and loss of life in flood-prone regions. However, there is still a lot of room for improvement and innovation to provide better predictions, especially for flash floods, particularly in urban areas  This is addressed in the present study, the goal of which it is to improve simulation and prediction of flash floods and to develop a spatial decision-making model for implementing flood protection measures. In this regard, different approaches for flood simulation and flood protection should be applied. The proposed methodology links flood hazard modeling, remote sensing and machine learning methods. Combining these physical models and data driven methods will result in a more reliable hybrid model that can be employed for prediction of (flash) floods and event analysis. In order to achieve the research goal of present study we: i) add more functionality to a hydrodynamic model code; ii) complement the latter with data driven methods ;iii) develop a spatial decision-making model framework for defining flood protection measures, iv) validate process-based and data driven methods, and finally v) cross-evaluate Light Detection And Radar (LiDAR) topography with available local super-resolution drone data to assess the ability to incorporate local flood defenses into the models. The most important outcome is the creation of valuable flood maps in areas where it matters - while accounting for effects of land use and climate change. This will serve scientists as well as land and risk management authorities with better actionable flood risk information in locations where people and assets are located and in danger. It also develops innovative methodologies for estimating the changing risk from flash floods based on land use scenarios and climate change projections. Moreover, developing spatial multi-criteria decision making (SMCDM) can help decision makers to determine suitable locations and methods for flood protection measures. These methods will be particularly valuable in the context of solving current challenges of accounting for and mitigating flash floods and the effects of climate change.
Pluvial flood catastrophe modelling: a trans-disciplinary approach.
Authors: Karagiorgos Konstantinos , Knos Daniel , Haas Jan , Halldin Sven , Blumenthal Barbara , Pettersson Andreas , Nyberg Lars
Published: March 2020

Pluvial floods are one of the most significant natural hazards in Europe causing severe damage to urban areas. Following the projected increase in extreme precipitation and the ongoing urbanization, these events play an important role in the ongoing flood risk management discussion and provoke serious risk to the public as well as to the insurance sector. However, this type of flood, remains a poorly documented phenomenon. To address this gap, Swedish Pluvial Modelling Analysis and Safety Handling (SPLASH) project aims to develop new methods and types of data that improve the possibility to value flood risk in Swedish municipalities by collaboration between different disciplines.

SPLASH project allows to investigating the impact of heavy precipitation along the entire risk modelling chain, ultimate needed for effective prevention. This study presents a pluvial flood catastrophe modelling framework to identify and assess hazard, exposure and vulnerability in urban context. An integrated approach is adopted by incorporating ‘rainfall-damage’ patterns, flood inundation modelling, vulnerability tools and risk management. The project is developed in the ‘OASIS Loss Modelling Framework’ platform, jointly with end-users from the public sector and the insurance industry.

The Swedish case study indicates that the framework presented can be considered as an important decision making tool, by establishing an area for collaboration between academia; insurance businesses and rescue services, to reduce long-term disaster risk in Sweden.
Atmospheric measurements over oceans on German research vessels
Authors: Kinne Stefan
Published: March 2020

Ground-based remote sensing of atmospheric properties complements satellite remote sensing from space. Hereby the well-defined solar background of ground-based samples offers data of higher accuracy, which help to constrain (needed) assumptions in global data-sets of satellite remote sensing and earth system modeling. With ground monitoring largely limited to land or island surfaces, efforts have been made to add at least a few reference data over oceans with atmospheric remote sensing activities during ship cruises of opportunity. This presentation reports on recent voyages with German Research vessels (i.e. SONNE, MERIAN, METEOR and POLARSTERN) and how samples on these voyages have contributed to a better representation of marine properties for aerosol, trace-gases and clouds. Aside from establishing references for satellite remote sensing and modeling, relationships among different atmospheric properties also offer observational constrains for parametrizations of atmospheric processes in modeling.  
Seasonal analysis of warm extreme events in Serbia from 1949 to 2017
Authors: Tosic Ivana , Putniković Suzana , Tošić Milica
Published: March 2020

Worldwide studies revealed a general increase in frequency and severity of warm extreme temperature events. In this study, extreme temperature events including Heat waves (HWs) are examined. Extreme indices are calculated based on daily maximum temperature (Tx). The following definitions are employed: SU - number of days with Tx > 25 °C, umber of days with Tx > 90th percentile, and WSDI - number of days in intervals of at least six consecutive days for which Tx is higher than the calendar day 90th percentile. Daily values of air temperatures from 11 meteorological stations distributed across Serbia were used for the period 1949–2017.

Trends of extreme temperature events and their frequencies are examined. The period 1949–2017 are characterised by a warming of extreme temperature indices (SU, Tx90, HWs). It is found that maximum air temperatures increased at all stations, but statistically significant at 6 stations in winter, 4 stations in summer and two stations in spring. The average number of SU per station was between 63.1 in Novi Sad to 73.5 in Negotin during the summer season. Significant increase of SU is recorded in summer for 10 out of 11 stations. Positive trends of SU and Tx90 are observed for all stations and seasons, except in Novi Sad. The average number of Tx90 is about 9 for all stations in all seasons. The longest heat waves prevailed in 2012, but the most severe are recorded in 2007. Increasing of warm extreme events in Serbia are in agreement with studies for different regions of the world.
Naturally Occurring Asbestos Assessment, Exposure Prevention Strategies During Construction, and Capping for Long-Term Protection: a California, USA Example
Authors: Kalika Sarah
Published: March 2020

The government of California, in the United States, has created requirements that are intended to protect the public from naturally occurring asbestos (NOA), partly due to the widespread areas in which asbestos minerals (including chrysotile and various amphiboles) are found within the state.Over ten years ago, the California Department of Toxic Substances Control Schools Unit published a thorough set of guidelines for addressing NOA at school construction sites.Their guidance document includes soil sampling procedures and frequency, recommended laboratory analytical testing methods, construction best practices to protect nearby residents from airborne exposures, capping methods to prevent re-exposure to students and public following the completion of the school improvement project, and follow-up procedures to ensure the capping method remains protective.Many of these best practices have been adapted into the construction process for commercial and residential buildings.  In California, protection of air is the regulated by Air Quality Management Districts, who regulate the generation of airborne asbestos as an air pollutant.Additionally, workers who are employed by a company, and working at a job site where asbestos is present, are protected by California Occupational Safety and Health (Cal-OSHA). Cal-OSHA requires varying protective measures to be implemented, based on the amount of asbestos that the worker is exposed to during their time at the construction project.This presentation will review the various regulations and best practices used in California by comparing a school construction project with a commercial office building.
The role of geodiversity in ecosystem development
Authors: Schaaf Wolfgang
Published: March 2020

Besides biodiversity, geodiversity is an important constituent of complex ecosystems. We define geodiversity here mainly as substrate and surface properties and topography.

Especially during initial stages of young ecosystems, the geodiversity of a site or landscape may have a lasting impact on dominating abiotic feedback mechanisms that set the stage for further ecological development.

The Chicken Creek catchment was constructed in the Lusatian mining area as a research platform to study initial ecosystem development at the landscape scale. The 6 ha site was formed as a hillslope with 2 to 3.5 % inclination. Up to 3.5 m of Pleistocene sands were dumped as an aquifer on top of a 1-2 m clay layer. The construction process using large-scale mining machinery resulted in slight differences in substrate properties in different parts of the catchment reflecting the natural variation in overburden material that was used for aquifer construction.

After completion of the construction in 2005, a cross-disciplinary long-term monitoring program was initiated to record major environmental parameters adapted to the development of the site. No amelioration, fertilization or planting was carried out to allow for primary succession.

Time series of environmental data recorded since 2005 revealed that the geodiversity of the initial site affected a number of both abiotic and biotic processes (e.g. surface runoff and erosion intensity, top soil development, colonization by plant functional traits, soil moisture and groundwater patterns, formation of biological soil crusts).

During its first 15 years, the Chicken Creek experimental catchment showed a very dynamic development. Whereas the abiotic geosystem of the first 2-3 years was characterized by heavy erosion and sediment transport, primary succession by invading vegetation and the unexpected formation of soil crusts within only a few years resulted in biotic-abiotic feedbacks that controlled catchment hydrology.

Our data indicate that even minor variations in initial substrate characteristics (e.g. texture) and stochastic single events like thunderstorms can have lasting impacts on the geomorphological, hydrological and biological development of the catchment.
Geophysics data management at the UK Polar Data Centre
Authors: Fremand Alice
Published: March 2020

The UK Polar Data Centre (UK PDC, https://www.bas.ac.uk/data/uk-pdc/) is the focal point for Arctic and Antarctic environmental data management in the UK. Part of the Natural Environmental Research Council’s (NERC) and based at the British Antarctic Survey (BAS), the UK PDC coordinate the management of polar data from UK-funded research and support researchers in complying with national and international data legislation and policy.

Reflecting the multidisciplinary nature of polar science, the datasets handled by the data centre are extremely diverse. Geophysics datasets include bathymetry, aerogravity, aeromagnetics and airborne radar depth soundings.  These data provide information about the seabed topography, the Earth’s geological structure and the ice thickness. The datasets are used in a large variety of scientific research and projects at BAS. For instance, the significant seabed multibeam coverage of the Southern Ocean enables BAS to be a major contributor to multiple international projects such as International Bathymetric Chart of the Southern Ocean (IBCSO) and Seabed 2030. That is why, it is crucial for the UK Polar Data Centre (PDC) to develop robust procedures to manage these data.

In the last few months’, the procedures to preserve, archive and distribute all these data have been revised and updated to comply with the recommendations from the Standing Committee on Antarctic Data Management (SCADM) and the requirements of CoreTrustSeal for a future certification. The goal is to develop standard ways to publish FAIR (Findable, Accessible, Interoperable and Reusable) data and set up workflows for long-term preservation and access to UK PDC holdings.
Effect of potential HONO sources on ROx budgets and SOA and PAN formation in North China in winter
Authors: Zhang Jingwei , An Junling
Published: March 2020

Recent wintertime observations in north China found high concentrations of nitrous acid (HONO), secondary organic aerosols (SOA) and peroxyacetyl nitrate (PAN), especially during heavy haze periods, indicating stronger atmospheric oxidation capacity in winter haze days. Researchers speculated that HONO formation was enhanced in haze days through NO2 heterogeneous reaction on aerosol surfaces, and high concentrations of HONO during daytime further improved SOA and PAN formation.

In this study, the WRF-Chem model updated with six potential HONO sources was used to quantify the impacts of potential HONO sources on the production and loss rates of ROx ( OH+HO2+RO2) radicals, and on the concentrations of SOA and PAN in the Beijing-Tianjin-Hebei (BTH) region of China during wintertime of 2017. HONO simulations were greatly improved after considering the six potential sources, NO2 heterogeneous reactions were the main sources of HONO. HONO photolysis was the key precursors of primary OH while the contribution of O3 photolysis to OH could be neglected, the potential HONO sources remarkably accelerated ROx cycles, significantly improved SOA and PAN simulations, especially in heavy polluted periods. The above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting relevant studies.
Late Orogenic Heating: Slab Breakoff or Slab Rollback?
Authors: Sizova Elena , Hauzenberger Christoph , Fritz Harald , Faryad Shah Wali , Gerya Taras
Published: March 2020

High- to ultrahigh pressure rocks ((U)HP) from some collisional orogens bear evidences of post collisional heating recorded by a β-shaped pressure–temperature–time (P–T–t) path. The post peak pressure heating segment of the P–T–t path, which can be well developed such as in the Bohemian Massif of the Variscan orogenic belt, occurs after the (U)HP rocks are exhumated from mantle depths to various crustal levels. This process is often explained by geologists as a result of mantle delamination or slab breakoff. Based on a two-dimensional coupled petrological–thermomechanical tectono-magmatic numerical model, we demonstrate that slab rollback during ongoing continental subduction can be considered as a possible mechanism responsible for the effective extraction of (ultra)high pressure metamorphic rocks and their later heating. This slab rollback scenario is further compared numerically with the classical continental collision scenario associated with slab breakoff. The mantle upwelling occurring in the experiments with slab breakoff, which is responsible for the heating of the exhumed crustal material, is not directly related to the slab breakoff but can be caused either by slab bending before slab breakoff or by post-breakoff exhumation of the subducted crust.
Organic carbon sorbed to reactive iron minerals released during permafrost collapse
Authors: Patzner Monique S. , Logan Merritt , Mueller Carsten W. , Joss Hanna , Anthony Sara E. , Scholten Thomas , Byrne James M. , Borch Thomas , Kappler Andreas , Bryce Casey
Published: March 2020

The release of vast amounts of organic carbon during thawing of high-latitude permafrost is an urgent issue of global concern, yet it is unclear what controls how much carbon will be released and how fast it will be subsequently metabolized and emitted as greenhouse gases. Binding of organic carbon by iron(III) oxyhydroxide minerals can prevent carbon mobilization and degradation. This “rusty carbon sink” has already been suggested to protect organic carbon in soils overlying intact permafrost. However, the extent to which iron-bound carbon will be mobilized during permafrost thaw is entirely unknown. We have followed the dynamic interactions between iron and carbon across a thaw gradient in Abisko (Sweden), where wetlands are expanding rapidly due to permafrost retreat. Using both bulk (selective extractions, EXAFS) and nanoscale analysis (correlative SEM and nanoSIMS), we found that up to 19.4±0.7% of total organic carbon is associated with reactive iron minerals in palsa underlain by intact permafrost. However, during permafrost collapse, the rusty carbon sink is lost due to more reduced conditions which favour microbial Fe(III) mineral dissolution. This leads to high dissolved Fe(II) (2.93±0.42 mM) and organic carbon concentrations (480.06±34.10 mg/L) in the porewater at the transition of desiccating palsa to waterlogged bog. Additionally, by combining FT-ICR-MS and greenhouse gas analysis both in the field and in laboratory microcosm experiments, we are currently determining the fate of the mobilized organic carbon directly after permafrost collapse. Our findings will improve our understanding of the processes controlling organic carbon turnover in thawing permafrost soils and help to better predict future greenhouse gas emissions.

 
Gully erosion susceptibility modelling for avoided degradation planning
Authors: Le Roux Jay , Van der Waal Bennie
Published: March 2020

Gully erosion can reach alarming dimensions and contribute significantly to soil loss and sediment yield in a catchment.  Since restoration resources are usually limited, strategic information on sensitive and erosion susceptible areas are needed to avoid future degradation.  Although the mapping of areas susceptible to gully formation is not a new concept, this study has potential in the Mzimvubu River Catchment, the only large river network in South Africa without a large reservoir.  The Tsitsa tributary’s catchment, where two large reservoirs are planned, consists of large areas of highly erodible soils with widespread gully erosion evident.  It is important to prevent further gully erosion in the catchment due to the presence of duplex and dispersive soils. Therefore, this study modelled areas that are susceptible to gully development in the Tsitsa River Catchment, as well as estimated the sediment yield potential from the susceptible areas if gully development occurs.  This was achieved by mapping gully-free areas in a GIS that have the same DEM-derived topographical variables, soil associations and land cover than gullied areas, followed by scenario analysis of the potential sediment yield.  More than 30 000 ha (7%) of the catchment is intrinsically susceptible to further gully development, consisting of drainage paths with a large contributing area and erodible duplex soils.  If not protected, these susceptible areas could contribute an additional 300 million m3 of sediment to the river network, reducing the volumes of both reservoirs by more than 50%. 
The Mesozoic granitic magmatism in Haliheiba: implications from geochronology, geochemistry and Hf isotopes
Authors: Wei Wei , Wu Xiyong
Published: March 2020

The Mesozoic granitic magmatism in Haliheiba is poorly understood because of lacking systematic data. Hence, this paper presents petrological observations, zircon U–Pb ages, geochemistry and Hf isotopes for these rocks. These rocks comprise granidiorite and quartz monzonite. Zircon LA-ICP-MS U–Pb dating yields emplacement ages of 247.6 ± 1.1 Ma and 247.0 ± 1.5 Ma for granidiorite and quartz monzonite, respectively. Geochemically, the granidiorite has SiO2 contents of 65.86–67.37 wt% and alkali concentrations of 7.97–8.44 wt%; the quartz monzonite has SiO2 contents of 66.95–67.28 wt% and alkali concentrations of 8.52–8.63 wt%, which belong to calc-alkaline series and are metaluminous rocks. These granitoids are enriched in light rare earth elements (LREEs) with (La/Yb)N values from 5.27 to 12.09 and have slightly to moderately negative Eu anomalies with δEu values from 0.53 to 0.78 in the chondrite-normalized REE diagram. Furthermore, these granitoids are relatively enriched Rb, U, Th, K, and Pb and slightly depleted in Nb, Ta, Ba, Ti, and P in the primitive mantle-normalized spider diagram. The above geochemical signatures reveal that these granites have I-type affinity. Zircon Hf isotope data show that these granitoids possess high positive εHf(t) values from +8.9 to +14.9 and fairly young Hf model ages from 305 to 620 Ma, indicating that they are mainly derived from partial melting of juvenile crustal components. Combined with regional geology, our results indicate that the Triassic magmatism in Haliheiba most likely resulted from the subduction of the Paleo-Asian Ocean beneath the North China Craton. Our results together with regional isotopic data suggest that a significant crustal accretion event occurred during the Neoproterozoic to Paleozoic in the Great Xing’an Range.
Internal Erosion of Soil Pipes: Still More Questions Than Answers
Authors: Wilson Glenn , Bernatek-Jakiel Anita , Nieber John L. , Fox Garey A.
Published: March 2020

Internal erosion of soil pipes can be a very important process in gully erosion as well as other mass failure events such as sinkholes, landslides and levee/dam breaching. Flow through preferential flow paths such as macropores can be rapid enough to exceed the soil critical shear stress and cause detachment of particles from the walls of the flow path, i.e. internal erosion. Development of a soil pipe from enlargement of a macropore results in more rapid flow and thus greater internal erosion, particularly mass failure of aggregates from pipe walls and roofs. If the sediment transport capacity of the pipe is exceeded, the pipe will plug causing back-pressure to build up within the soil pipe, which can foster hillslope instability. However, limited research has been conducted on particle and aggregate detachment within soil pipes as well as transport of sediment through soil pipes. The objective of this paper is to present observations of little known and poorly described processes involved in pipeflow and the resulting internal erosion of soil pipes. Many of the processes involved in internal erosion of soil pipes are assumed based upon processes observed in surface and stream erosion studies but are so poorly quantified for soil pipes that they are yet to be transferable. For example, the role of solution chemistry on sediment detachment from pipe walls has been quantified to a limited extent but little has been done on the effects of seepage forces on particle detachment in pipes and even less done on sediment transport capacity of soil pipes. Recent advances have included: development of suspended sediment and bedload rating curves for soil pipeflows but the results are crude and warrant further study. Quantification of the interactive effects of surface flow in channels with flow through soil pipes below channels on headcut migration and gully widening is in its infancy. Other processes, such as air-entrapment in creating or temporarily plugging pipes, have been suggested as important but lack quantification. These processes and others combine to result in internal erosion of soil pipes but they must be better understood and quantified in order to develop the next generation of soil erosion models and landscape morphology prediction technologies.
Characterising diurnal- and synoptic-timescale changes in urban air quality using Radon-222
Authors: Chambers Scott , Kikaj Dafina , Podstawczyńska Agnieszka , Crawford Jagoda , Williams Alastair
Published: March 2020

Urban air quality is strongly influenced by the atmosphere’s ability to disperse primary emissions and opportunities for secondary pollution formation. In mid- to high-latitude regions that experience enduring winter snow cover or soil freezing, regional subsidence and stagnation associated with persistent anti-cyclonic conditions such as the “Siberian High” can lead to “cold pool” or “persistent inversion” events. These events can result in life-threatening pollution episodes that last for weeks. While often associated with complex topography [1,2], persistent inversion events can also influence the air quality of urban centres in flat, inland regions [3]. This presentation will describe a recently-developed radon-based technique for identifying and characterising synoptic-timescale persistent inversion events, which is proving to be a simple and economical alternative to contemporary meteorological approaches that require regular sonde profiles [1]. Furthermore, key assumptions of the radon-based technique to characterise diurnal-timescale changes in the atmospheric mixing state described by Chambers et al. [4] are violated during persistent inversion conditions. Here we demonstrate how atmospheric class-typing, through successive application of radon-based techniques for identifying synoptic- and diurnal-timescale changes in the atmospheric mixing state, improves understanding of atmospheric controls on urban air quality in non-summer months across the full diurnal cycle. This knowledge translates directly to statistically-robust techniques for assessing public exposure to pollution, and for evaluating the efficacy of pollution mitigation measures. Lastly, we show how atmospheric class-typing can be used to enhance the evaluation of chemical transport models [5].

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[2] Kikaj, D., et al. Atmos. Meas. Tech., 12, 4455–4477, https://doi.org/10.5194/amt-12-4455-2019, 2019.

[3] Chambers, SD and A Podstawczyńska. Atmos. Environ., 219, 117040, https://doi.org/10.1016/j.atmosenv.2019.117040, 2019.

[4] Chambers, S.D., et al. J. Geophys. Res. Atmos. 124, 770–788, https://doi.org/10.1029/2018JD029507, 2019.

[5] Chambers, S.D., et al. Atmosphere 10 (1), 25, doi:10.3390/atmos10010025, 2019.