bluuebunny/crossref_metadata_2025 huggingface dataset:
Accessing environmental time series data in R from Sensor Observation Services with ease
Authors: Nüst Daniel , Jürrens Eike H. , Gräler Benedikt , Jirka Simon
Published: March 2020

Time series data of in-situ measurements is the key to many environmental studies. The first challenge in any analysis typically arises when the data needs to be imported into the analysis framework. Standardisation is one way to lower this burden. Unfortunately, relevant interoperability standards might be challenging for non-IT experts as long as they are not dealt with behind the scenes of a client application. One standard to provide access to environmental time series data is the Sensor Observation Service (SOS, ) specification published by the Open Geospatial Consortium (OGC). SOS instances are currently used in a broad range of applications such as hydrology, air quality monitoring, and ocean sciences. Data sets provided via an SOS interface can be found around the globe from Europe to New Zealand.

The R package sos4R (Nüst et al., 2011) is an extension package for the R environment for statistical computing and visualization (), which has been demonstrated a a powerful tools for conducting and communicating geospatial research (cf. Pebesma et al., 2012; ). sos4R comprises a client that can connect to an SOS server. The user can use it to query data from SOS instances using simple R function calls. It provides a convenience layer for R users to integrate observation data from data access servers compliant with the SOS standard without any knowledge about the underlying technical standards. To further improve the usability for non-SOS experts, a recent update to sos4R includes a set of wrapper functions, which remove complexity and technical language specific to OGC specifications. This update also features specific consideration of the OGC SOS 2.0 Hydrology Profile and thereby opens up a new scientific domain.

In our presentation we illustrate use cases and examples building upon sos4R easing the access of time series data in an R and Shiny () context. We demonstrate how the abstraction provided in the client library makes sensor observation data for accessible and further show how sos4R allows the seamless integration of distributed observations data, i.e., across organisational boundaries, into transparent and reproducible data analysis workflows.

References

Nüst D., Stasch C., Pebesma E. (2011) Connecting R to the Sensor Web. In: Geertman S., Reinhardt W., Toppen F. (eds) Advancing Geoinformation Science for a Changing World. Lecture Notes in Geoinformation and Cartography, Springer.

Pebesma, E., Nüst, D., & Bivand, R. (2012). The R software environment in reproducible geoscientific research. Eos, Transactions American Geophysical Union, 93(16), 163–163.
WISDOM Calibration and Data Processing Pipeline for the ExoMars 2020 Mission
Authors: Plettemeier Dirk , Statz Christoph , Lu Yun , Benedix Wolf-Stefan , Hegler Sebastian , Herve Yann , Oudart Nicolas , Legall Alice , Corbel Charlotte , Hamran Svein-Erik , Ciarletti Valerie
Published: March 2020

The WISDOM instrument is part of the 2020 ESA-Roscosmos ExoMars Rosalind-Franklin rover payload. It is a fully-polarimetric ground penetrating RADAR (GPR) operating as a stepped-frequency continuous-wave radar at frequencies between 500 MHz and 3 GHz yielding a centimetric resolution and a penetration depth of about 3 m in Martian soil. WISDOMs primary scientific objective is the detailed characterization the material distribution of the Martian subsurface as a contribution to the search for evidence of present and past life.

WISDOM  works by transmitting electromagnetic waves in the observable zone of the subsurface below the antenna. The transfer function of the observed zone is then recovered from the received signal. The processing of the WISDOM data involves several calibration steps, where environment and temperature as well as instrument influences are compensated in order to obtain interpretable results. The data processing involves several filters that are designed to extract and quantify features of interest w.r.t. the surface and subsurface. Calibration and processing are implemented in the WISDOM Data Processing Framework (WDPF). It can be operated manually (via GUI integration) as well as automatically as part of the ROCC processing pipeline yielding comparable and reproducible results from automatic and manual processing of WISDOM data. The capabilities of WDPF are validated on laboratory and field measurements performed with the WISDOM instrument.
Tectonic evolution of the East Vietnam-Southwest Borneo margin breakup
Authors: Chang Sung-Ping , Pubellier Manuel , Delescluse Matthias , Nirrengarten Michael , Mohn Geoffroy , Chamot-Rooke Nicolas , Qiu Yan
Published: March 2020

We investigate the extensional processes occurring during the rifting of a marginal basin to use long-streamer multichannel seismic transects across the entire southwestern South China Sea (SCS). The basin is characterized by space and time propagating breakup followed by seafloor spreading during Cenozoic. Stretching and thinning of the continental crust were accompanied by ubiquitous large extensional detachment faults. In the proximal E Vietnam margin, rifted basins are filled with lower syn-rift sedimentation (syn-rift I). These sediments pinch out towards the distal margin. On the conjugate NW Borneo margin, the same coeval syn-rift I is truncated at the top, suggesting a period of crustal uplift affecting solely the southern margin. To illustrate the pre-breakup geometries of the southwestern SCS margins, we restore two conjugate sections near the first oceanic magnetic anomaly (20.1 Ma, C6n). The result highlights a thick pre-breakup succession (syn-rift II) offset slightly by several seaward-dipping normal faults above the exhumed basement. The magmatism intruded this hyper-extended basin and proceeded to break up the continental lithosphere eventually. The COT configuration not only illustrates asymmetrical hyper-extension but also appears in map view to have a rhombic shape controlled by N-S abrupt segments and E-W hyper-extended ones. The spatial variation of the crustal structures suggests an initial N-S extension contemporaneous with the first phase of seafloor spreading in the eastern SCS. The extensional direction significantly changed later (circa 23Ma) to NW-SE in relation to a well-documented ridge jump. Interestingly, this change in the direction of opening is coeval with the collision and the counterclockwise rotation in Borneo, thus suggesting that those events are linked. Therefore, we propose that collision was responsible for significant change in the far-field stress and influenced the extensional regime in the SCS.
Attributing Chinese Hydrological Extreme EventsAttributing Chinese Hydrological Extreme Events
Authors: Tett Simon ,   The CSSP China Event Attribution Team
Published: March 2020

In 2018 & 2019 China was impacted by three extreme hydrological events. Heavy rainfall in Central China during summer 2018, heavy summer rainfall in south eastern China during 2019 and a severe drought in Yunnan in May/June of 2019. Using the Hadley Centre’s state-of-the-art attribution system the role of anthropogenic forcing in the changing risk of these events was studied. The modelling system uses two large ensembles of a 60 km resolution atmospheric model driven with sea-surface temperatures(SST), sea-ice and a package of different forcings. One ensemble  uses observed SSTs and natural and human forcings while the other uses pre-industrialised SSTs and natural forcings.  The studies were done in two week-long workshops held in China which aimed to train early career researchers to carry out event attribution studies. The methodologies used in all studies were similar. In all three cases, anthropogenic forcing reduced the risk of heavy rainfall and increased the risk of drought.  Changes in risk for the three events are surprisingly large with the probability of the  Yunnan drought increasing by a factor of 14, the probability of the summer 2019 heavy rainfall declining by a factor of four, and the probability of the summer 2018 rainfall event declining by a half.  Aerosol induced circulation changes in the model are the likely reason for these changes.
The response of Northern Hemisphere polar lows to2climate change in a 25 km high-resolution global climate model
Authors: Shaffrey Len , Bresson Helene , Hodges Kevin , Zappa Giuseppe
Published: March 2020

Polar lows are small, intense cyclones that form at high latitudes during winter. Their high wind speeds and heavy precipitation can have substantial impacts on shipping, coastal communities and infrastructure. However, climate models typically have low resolutions and therefore poorly simulate Polar Lows. This reduces the conﬁdence that can be placed in future projections of extreme high latitude weather and associated risks.

In this study, Polar Lows are assessed for the ﬁrst time in a high-resolution (25 km) global climate atmosphere-only model, N512 HadGEM3-GA3, for both present-day and future RCP 8.5 climate scenarios. Using an objective tracking algorithm, the representation of Polar Lows in the N512 HadGEM3-GA3 present-day simulation is found to agree reasonably well the NCEP-CFS reanalysis. RCP8.5 scenario conditions are generated by adding SST changes between 1990-2010 and 2090-2110 from the RCP8.5 experiments with the HadGEM2-ES model to observed SSTs from the present-day climate. In the RCP8.5 N512 HadGEM-GA3 simulations, the number of Northern Hemisphere Polar Lows are projected to substantially decrease (by over 60%) by the end of the 21st century, which is largely due to an increase in atmospheric static stability. However, new regions of Polar Low activity along the northern Russian coastlines are found where the Arctic sea ice is projected to retreat.
Using Data From Personal Weather Stations to Improive Precipitation Estimation and Interpolation
Authors: Seidel Jochen , El Hachem Abbas , Bárdossy András
Published: March 2020

The number of private meteorological stations with data available online through the internet is increasing gradually in many parts of the world. The purpose of this study is to investigate the applicability of these data for the spatial interpolation of precipitation for high intensity events of different durations. Due to unknown biases of the observations, rainfall amounts of the secondary network are not considered directly. Instead, only their temporal order is assumed to be correct. The crucial step is to find the stations with informative measurements. This is done in two steps, first by selecting the locations using time series of indicators of high precipitation amounts. The remaining stations are checked whether they fit into the spatial pattern of the other stations. Thus it is assumed that the percentiles at the secondary network accurate. These percentiles are then translated to precipitation amounts using the distribution functions which were interpolated using the weather service data only. The suggested procedure was tested for the State of Baden-Württemberg in Germany. A detailed cross validation of the interpolation was carried out for aggregated precipitation amounts of 1, 3, 6, 12 and 24 hours. For each aggregations, nearly 200 intense events were evaluated. The results show that filtering the secondary observations is necessary, the interpolation error after filtering and data transformation decreases significantly. The biggest improvement is achieved for the shortest time aggregations.
Modeling the redox potential during the infiltration in a recharge pond located in the Llobregat river basin
Authors: Rodriguez-Escales Paula , Barba Carme , Sanchez-Vila Xavier , Folch Albert
Published: March 2020

Redox potential measurements are a sink of multiple processes and factors related to the hydrochemistry of a water.  Normally, by themselves, they do not provide enough information to describe all the processes occurring in a system and they are considered only as “an indicator” that combined with a more detailed hydrochemistry can provide information of the driving processes. There are different reasons why these measurement are not quantitatively valid. First of all, sampling plays an important role. The most common method to determine Eh in groundwater is by using an Eh probe and a cell flow, which implies, by itself, mixing of waters. On the other hand, the Eh reproducibility is also conditioned by the amount of processes considered in a numerical model. Eh depends on several geochemical processes, which at the same time, they are depending on flow and heat transport. The last achievements in sensoring science has allowed to develop sensor probes that allows the Eh measurements in a non-invasive and a continuous way.

Considering this, in this work we have monitored intensively an infiltration pond (in the context of Managed Aquifer Recharge) in order to develop a proper model to reproduce the Eh. The monitoring was based in the use of non-invasive Eh probes, which registered the Eh every 15 min during a year. During that year, four hydrochemical campaigns were also developed in order to quantify the hydrochemistry of the site. On the other hand, the model considered the flow of the system, the heat transport and a set of geochemical processes which were also depending on temperature. The main processes were the generation of organic matter in the own system, the oxidation of organic carbon using different TEAPs, nitrification and different secondary geochemical processes related, specially, to iron and manganese geochemistry.
Hydraulic fracture oscillations in response to strong impulse
Authors: Pasternak Elena , Dyskin Arcady
Published: March 2020

Hydraulic fractures and the natural fractures in rock masses are closed by the in-situ compressive stress such that their opposite faces are in contact either with each other or with the proppant in hydraulic fractures or with gouge in the natural fractures. Subsequently, a pressure increase can produce negligible deformation in already closed fractures as compared to the deformation associated with the opening caused by sufficiently large tensile stress. This suggests a simple model of closed fracture as a bilinear spring with a certain stiffness in tension and a very high (potentially infinite) stiffness in compression. Therefore the oscillations of fractures can be reduced to the oscillations of a bilinear oscillator or impact oscillator [1] when the compressive stiffness considerably exceeds the tensile one. We use the simplest model of the impact oscillator with preload representing the action of the in-situ compressive stress. Based on this model, two sets of multiple resonances are identified and the reaction to impulsive load is determined. The harmonics of free oscillations are calculated. The knowledge of the first two harmonics is sufficient to recover the tensile stiffness and hence identify the geometric parameters of the fracture. The results of the research contribute to the development of the methods of fracture reconstruction and the hydraulic fracture monitoring.

Dyskin, A.V., E. Pasternak and E. Pelinovsky, 2012. Periodic motions and resonances of impact oscillators. Journal of Sound and Vibration 331(12) 2856-2873. ISBN/ISSN 0022-460X, 04/06/2012.

Acknowledgements. The authors acknowledge support from the Australian Research Council through project DP190103260. AVD acknowledges the support from the School of Civil and Transportation, Faculty of Engineering, Beijing University of Civil Engineering and Architecture.
New insights of Tripoli and “Calcare di Base” Formations from Caltanissetta (Sicily) and Rossano (Calabria) Basins: a detailed geochemical, sedimentological and bio-cyclostratigraphical study.
Authors: Tzevahirtzian Athina , Blanc-Valleron Marie-Madeleine , Rouchy Jean-Marie , Caruso Antonio
Published: March 2020

A detailed biostratigraphical and cyclostratigraphical study provided the opportunity of cycle-by-cycle correlations between sections from the marginal and deep areas of the Caltanissetta Basin (Sicily), and the northern Calabrian Rossano Basin. All the sections were compared with the Falconara-Gibliscemi composite section. We present new mineralogical and geochemical data on the transition from Tripoli to Calcare di Base (CdB), based on the study of several field sections. The outcrops display good record of the paleoceanographical changes that affected the Mediterranean Sea during the transition from slightly restricted conditions to the onset of the Mediterranean Salinity Crisis (MSC). This approach permitted to better constrain depositional conditions and highlighted a new palaeogeographical pattern characterized by separated sub-basins. The sedimentological and geochemical parameters of these basins introduced a different and diachronous response to the global constraints of the MSC. Our preliminary results display already evidences of paleoenvironmental changes: (1) a lithological transition passing from the Tripoli’s triplet (grey marls, reddish laminites and diatomites) to the complex carbonates of CdB; (2) the appearance of evaporite pseudomorphs implying early stage diagenesis; (3) the presence of sulphur-rich deposits involving process of bacterial sulphate reduction. The local transition from the uppermost part of the Tripoli cycles to the CdB reflects the worsening of the marine connections, leading to the individualisation of semi-closed settings where the marine inputs were not great enough to balance the effects of the climate fluctuations and especially of the evaporation/precipitation budget.
Water well logging and automatic log interpretation technology
Authors: Manstein Yuri , Alsynbaev Kamil
Published: March 2020

The presented work is fully practical. Hydrogeological (water) well logging is very different from a petroleum well logging in terms of equipment and budget. A water uplift well cost is quite low, and it is not make a big economic sense to use automatic well logging systems for it. Hence, a lot of engineers are trying to "invent" their own resistivity logging tools or just use a conventional AMNB equipment for surface electrical prospecting to explore the water wells. It is feasible, because a water depth and, consequently, the logging cable length is usually limited by 200 m, it is not hard to pull the cable manually. Such a solution is very cheap and easy to implement. However, the process of logging take time and includes hundreds of steps. So, errors in the process is often.

The aim of this work is to adapt electric resistivity imaging system SibEr for well logging, simplify the logging process and create the possibility for a well drilling team to make the well logging themselves, including the recommendation of the filter installation depth.

The solution includes:

- Hardware: well logging cable with 32 (24) takeouts at the bottom hole end with 20 cm spacing;

- Embedded software for resistivity and induced polarization data acquisition;

- Data processing software to create the logging report with diagrams and suggested filter intervals.

 
Control of karst areas on space-time dynamics of floods, by combining annual and event-based analyses
Authors: Le Mesnil Martin , Charlier Jean-Baptiste , Moussa Roger , Caballero Yvan , Dörfliger Nathalie
Published: March 2020

The study of flood risks requires a better understanding of the hydrological response of catchments, by identifying the drivers responsible for their variability, such as seasonal and regional rainfall patterns, initial catchment conditions and geology. Many catchments are not conservative, mainly due to Interbasin Groundwater Flows (IGF), that limits the application of traditional water balances methods on a regional scale. The role of karst areas on IGF is highly suspected to promote particular hydrological processes that change the annual water budgets as well as flood event dynamics.

The aim of our work is to assess the impact of IGF in karst and non-karst catchments of medium size (100-500 km²), on annual water budgets and flood dynamics. To this end, we developed a two-step methodology, applied on 120 elementary catchment in France, for which daily rainfall and runoff time series of several decades were available.

First, the traditional annual water budget method of L’vovich was adapted to non-conservative catchments, including an explicit term of IGF, as well as hydrograph decomposition. Results show that IGF occurrence is linked to the presence of karst areas, and that it affects both flood and baseflow components, sometimes in a very significant way. Second, a flood event analysis was conducted using a hydrograph characterization, including the analysis of lateral losses and gains on reaches delimited by 2 stations. The variability of these parameters was then studied as a function of seasonal and regional rainfall patterns, initial catchment conditions, and geology. Results show that geology (with the presence of karst areas) affect all parameters (flood shape and lateral exchanges), while rainfall pattern and initial catchment conditions mainly influence the flood dynamics.

Globally, our results show that, in addition to classical drivers (rainfall & initial catchment conditions), the spatial variability of flood pattern and dynamics is highly influenced by geology and notably karst areas. This study brings ways to improve the efficiency of hydrological models, by including IGF as a specific process. Results are also interesting in terms of extension to ungauged basins, as IGF occurrence is linked to the occurrence of karst areas.
Climate Change effects on the River Discharge in Bulgaria
Authors: Mavrova-Guirguinova Maria
Published: March 2020

The impact of future climate change under IPCC scenarios RCP4.5 and RCP8.5 on hydrological regimes in plain catchments up to 650 m high and in mountainous areas of Bulgaria is discussed. A hydrological simulation models (TUWmodel) were calibrated on recorded data and ‘forced’ in the selected scenarios with precipitation and air temperature data from ALADIN 5.2, a local version of the French global atmospheric model ARPEGE, downscaled to a grid of 12 km. Simulations for the future periods 2013-2042, 2021-2050 and 2071-2100 are compared to the flows in the reference period 1976-2005.

Results indicate increased seasonality of flows, with noticeably drier summers and increase of river discharge in winter. In most of the cases the analysis of extreme events suggests significant increases in the frequency of both high‐ and low‐flow events. The change in the extreme runoff with a large repetition period required for the design of flood protection structures and systems has been investigated in regions with different mechanisms for flood generation. With the push of RCP4.5 or RCP8.5 scenarios the significant increase in flood peaks is observed in most of the river basins. There is a general trend of decreasing runoff with a 95% probability of exceedance.
Simulating an abrupt termination of the Holocene African Humid period using an optimised configuration of HadCM3
Authors: Hopcroft Peter , Valdes Paul , Ingram William , Ivanovic Ruza
Published: March 2020

The Holocene ’greening’ and subsequent, possibly abrupt desertification of the Sahara is a fascinating example of natural environmental change. It was driven by a gradual decline in summer insolation but with land-atmosphere coupling by vegetation likely providing additional reinforcing feedbacks. However, the majority of general circulation models (GCMs) cannot produce enough precipitation to sustain a ’Green’ Sahara, and the transient evolution through the Holocene has therefore only been studied with a few models. We present a suite of transient simulations with the coupled atmosphere-ocean GCM HadCM3, the CMIP3 version of the Met Office’s Hadley Centre model. These simulations cover the Holocene from 10,000 years before present, and optionally include recently developed optimisations of the atmospheric convection and dynamic vegetation parameterisations. In the model run with both optimisations, HadCM3 shows a convincing ‘greening’ for the first time. This is followed by a series of abrupt oscillations in vegetation cover and hydrology, that culminates in an abrupt collapse at around 6000 years before present. We compare the behaviour in four model versions and make a detailed evaluation with available geological evidence. Our results show that the stability of climate models is determined by chosen parameter values and formulations. We conclude that novel methods of inferring suitable model state-space regions using both present day observations and palaeoclimate reconstructions are needed.
Origin and propagation of sedimentary sequences throughout the Escanilla fluvial routing system (South Pyrenean foreland basin)
Authors: Valero Luis , Beamud Elisabet , Garcés Miguel , Vinyoles Andreu , Sharma Nikhil , Watkins Stephen E. , Tremblin Maxime , Puigdefàbregas Cai , Guillocheau François , Whitakker Alex C. , López-Blanco Miguel , Arbués Pau , Castelltort Sébastien
Published: March 2020

During middle Eocene, the Escanilla fluvial system transported and deposited material from East to West in the southern Pyrenees foreland basin. The paleogeography and sedimentology of the source to sink system is well established. The temporal framework is made of scattered low resolution magnetostratigraphies, and a robust temporal framework in the most distal (Olson) and most proximal (Sis) parts of the system. We built a new high resolution magnetostratigraphy from the middle part of the system, the Lascuarre section. The correlation of Lascuarre with the high resolution magnetostratigraphies and the integration of these data with other available chronological constraints results into a robust complete temporal framework from source to sink.

Sedimentological analyses of the Lascuarre section allow recognizing a set of sedimentary sequences throughout the record. Here we present the result of the analyses, and discuss the relative weight of the different forcing. Particularly, we elucidate the role of tectonics in relation to subsidence distribution patterns, and also the distinct expression of climate. Eventually, we identify and explore the signal propagation mechanisms of climate aberrations and of quasi-regular orbital variations along the routing system.
New onshore/offshore evidence of the Messinian Erosion Surface from key areas: the Ibiza-Balearic Promontory and the Orosei-Eastern Sardinian margin
Authors: Maillard Agnès , Gaullier Virginie , Lézin Carine , Chanier Frank , Odonne Francis , Lofi Johanna
Published: March 2020

As the Messinian sea-level drawdown associated with the Messinian Salinity Crisis is still questioned, we propose to show that the widely spread erosion surface affecting the Mediterranean margins is indeed linked to an exondation demonstrated from offshore and onshore data.

Our study presents for the first time a comprehensive onshore to offshore correlation of the Messinian erosional surface, and it is focused on small drainage systems or interfluve areas, outside of evaporite basins or incised canyons, where the Messinian erosion had not yet been studied previously: around Ibiza on the Balearic Promontory and around Orosei on the Eastern Sardinian margin, Tyrrhenian Basin, both areas where new offshore data were recently acquired. We show that the late Messinian erosion formed in subaerial settings, as testified by evidence of continentalization events, and attests for a regression phase that was correlated from the offshore continental slopes to the onshore paleo-platforms in both areas. Characteristics of this erosion in both study areas strengthen the scenario with at least one important low-stand sea-level for the Messinian Salinity Crisis with evaporites subbasins lying at different depths and possibly disconnected.
The impacts of long-term, high intensity N addition on the chemical composition of soil organic matter in a boreal forest
Authors: Hasegawa Shun , Marshall John , Näsholm Torgny , Bonner Mark
Published: March 2020

The intense use of fertilisers for agricultural and forest management purposes as well as atmospheric nitrogen (N) deposition has changed ecosystem stoichiometry in some parts of the planet, drawing great attention to the long-term impacts of N additions on carbon (C) sequestration. Soil organic matters (SOMs) are the major sink of C in terrestrial ecosystems and hence it is essential to understand the impacts of N addition on SOM not only quantitatively but also qualitatively. In temperate and boreal forests, chronic N addition generally suppresses SOM decomposition and increases C accumulation. The potential mechanisms for this have long been discussed and yet to be unearthed.

Here, we examined the impacts of long-term N addition on the chemical composition of SOMs in boreal forests situated in northern Sweden under two vegetation types (Norway spruce or Scots pine) and a range of N addition regimes where N addition rates varied between 3 and 70 kg N ha-1 year-1, duration between 12 and 32 years and total added amount between 50 and 2000 kg N ha-1. Soil samples were collected from the organic layer (litter and humus layers) and analysed for the chemical composition of SOMs using two metrics: pyrolysis gas chromatography–mass spectrometry (GC/MS) and solid-state 13C nuclear magnetic resonance spectroscopy (13C-NMR).

We found that the chemical composition of SOMs shifted with soil C:N ratios regardless of vegetation types, or duration and rates of N addition. Preliminary results suggest that the observed shift in chemical composition in SOMs may have been attributed to altered decomposition of lignin and carbohydrate-derived compounds. This was in line with previous research conducted in the same study sites that demonstrated added-N enhanced non-enzymatic brown-rot lignin oxidation relative to enzymatic white-lot lignin mineralisation. Here, the comprehensive examination of SOM chemical composition demonstrates altered molecular characteristics of SOMs with soil C:N conditions. This may help us to elucidate the mechanisms by which N addition alters the balance of decomposition and accumulation of SOMs.
On the development and operationalization of an impact-based forecasting system to support early action for river floods in Zambia
Authors: Giodini Stefania , Teklesadik Aklilu , Visser Jannis , Canavan Orla , Bwalya Innocent , Amuron Irene , van den Homberg Marc
Published: March 2020

Flooding in Zambia occurs on almost an annual basis greatly affecting the livelihoods of communities. Early action is crucial to mitigate the impact of flooding but needs to be guided by an early warning that is credible and actionable, linked to situational awareness based on data.  The 510 data team at the Netherlands Red Cross has been working together with the Red Cross Red Crescent Climate Centre, Zambia Red Cross Society, Water Resources Management Authority (WARMA) and Zambia Disaster Management and Mitigation Unit (DMMU) to develop a data driven early warning system to support impact based early action implementation. The system has been co-designed with the relevant local stakeholders and  integrates a hydrological model with a vulnerability capacity assessment based on secondary data for the whole country at the highest level of possible granularity (district level). A threshold based trigger model has been developed together with local decision makers to activate the system with a lead time up to 7 days. The system is being integrated in the Emergency Operation Centre operated by Zambia's DMMU as a part of the country standard early action protocol. This paper describes the system design, results from the first activations and lessons learned. 
Soil Moisture Retrievals from Unmanned Aerial Systems (UAS)
Authors: zhuang ruodan , Manfreda Salvatore , Zeng Yijian , Su Zhongbo , Romano Nunzio , Ben Dor Eyal , Maltese Antonino , Capodici Fulvio , Paruta Antonio , Nasta Paolo , Francos Nicolas , Ciraolo Giuseppe , Szabó Brigitta , Mészáros János , Petropoulos George P.
Published: March 2020

Quantification of the spatial and temporal behavior of soil moisture is vital for understanding water availability in agriculture, ecosystems research, river basin hydrology and water resources management. Unmanned Aerial Systems (UAS) offer a great potential in monitoring this parameter at sub-meter level and at relatively low cost. The standardization of operational procedures for soil moisture monitoring with UAS can be beneficial to understanding and quantify the quality of retrieved soil moisture (e.g., from different platforms and sensors).

In this study, soil moisture retrieved from UAS using different retrieval algorithms was compared to collocated ground measurements. The thermal inertia model builds upon the dependence of the thermal diffusion on soil moisture. The soil thermal inertia is quantified by processing visible and near-infrared (VIS-NIR) and thermal infrared (TIR) images, acquired at two different times of a day. The temperature–vegetation trapezoidal model is also used to map soil moisture over vegetated pixels. This trapezoidal model depicts the soil moisture dependence of the surface energy balance. The comparison of the two algorithms helps define a preliminary standard procedure for retrieving soil moisture with UAS.

As a case study, a typical cropland area with olive orchard, cherry and walnut trees in the region of Monteforte Cilento (Italy, Salerno) is used, where optical and thermal images and in situ data were simultaneously acquired. In the Alento observatory, long-term studies on vadose zone hydrology have been conducting across a range of spatial scales. Our findings provide an important contribution towards improving our knowledge on evaluating the ability of UAS to map soil moisture, in support of sustainable natural resources management and climate change studies.

This research is a part of EU COST-Action “HARMONIOUS: Harmonization of UAS techniques for agricultural and natural ecosystems monitoring”.

Keywords: soil moisture, Unmanned Aerial Systems, thermal inertia, HARMONIOUS
Dipole strength during the Matuyama-Brunhes reversal reconstructed from the deconvolution of magnetic and climatic modulation of 10Be/9Be records
Authors: Egli Ramon , Savranskaia Tatiana , Valet Jean-Pierre , Bassinot Franck , Meynadier Laure , Simon Quentin , Bourlès Didier , Thouveny Nicolas
Published: March 2020

The global production rate of the cosmogenic isotope 10Be by cosmic ray spallation is modulated by the activity of the sun and the intensity of the far-reaching component of the Earth magnetic field, which is in turn dominated by the dipolar term. Therefore, sedimentary 10Be records can be used to reconstruct past variations of the geomagnetic dipole moment. However, several environmental factors affect the transfer of 10Be atoms from the high atmosphere and soils, where it is produced, to the sediment, introducing a significant climatic modulation that can, in worst cases, completely obscure the paleomagnetic signal. These factors include variations of the continental runoff, oceanic circulation, sediment fluxes, and sediment scavenging effi­ciency. The latter is largely removed by normalizing the 10Be record with the concentration of authigenic 9Be, which is accumulated by sediment particles in the same manner as the cosmo­genic isotope. Even with this correction in place, individual 10Be/9Be records are significantly influenced by climate, to the point that only major geomagnetic events, such as the MB reversal, can be recognized. We present a model, which, for the first time, enables to deconvolve, at least partially, the climatic and magnetic components of 10Be/9Be records on a set of cores from the Atlantic, Indian, and Pacific Ocean. The climatic modulation is composed of an additive term, which reflects Be recycling through diagenetic release from sediments, and a multiplicative term, which is dominated by oceanic current patterns. Knowledge of these terms enables to remove, at least partially, site-specific environmental effects, obtaining a corrected 10Be/9Be stack that can be inverted to reconstruct variations of the dipole moment during the last geomagnetic reversal.
Measuring night-time urban heat island. Still a pending issue
Authors: Roca Josep , Arellano Blanca
Published: March 2020

The study of urban heat island (UHI) is of great relevance in the context of climate change (CC) and global warming. Cities accumulate heat in urban land covers as well as in built infrastructures, representing true islands of heat in relation to their rural environment, less urbanized. The literature on urban climate has highlighted the singular importance of night UHI phenomenon. It is during the night that the effects of UHI become more apparent, due to the low cooling capacity of urban construction materials and is during nighttime that temperatures can cause higher health risks, leading to the aggravation of negative impacts on people’s health and comfort in extreme events such as heat waves becoming more and more frequent and lasting longer. However, the study of nocturnal UHIs is still poorly developed, due to the structural problems regarding the availability of land surface and air temperature data for night time.

Traditional methods for obtaining nocturnal UHI have been directed either to extrapolation of data from weather stations, or obtaining air temperatures through urban transects. In the first case, the lack of weather stations in urban landscapes makes it extremely difficult to obtain data to extrapolate and propose models at a detailed resolution scale. In the second case, there is a manifest difficulty in obtaining data simultaneously and significantly representative of urban and rural zones. Another used methodology for measuring the nocturnal UHI is remote sensing from MODIS images, but the greatest limitation about this method is the low resolution, therefore it is clear the need for open source databases with better or higher resolution to quantify the night surface temperature.

This paper aims to develop a model for nocturnal UHI analysing several areas of Alta and Baja California as well as in the Mediterranean Coast, using data from the Landsat thermal bands (with an spatial resolution of 30 square meters per pixel) and contrasting Landsat's very limited nighttime images with daytime ones. The contrast allows the construction of “cooling” models of the LST based on geographical characteristics (longitude, latitude, distance to the sea, DTM, slope, orientation, etc.) and urban-spatial parameters (land uses and land covers), which are likely to be extrapolated to different time periods.
Myco-phytoremediation of mercury polluted soils in Ghana and Burkina Faso
Authors: Blagodatsky Sergey , Ehret Miriam , Rasche Frank , Hutter Imke , Birner Regina , Dzomeku Beloved , Neya Oble , Cadisch Georg , Wünsche Jens
Published: March 2020

Unregulated surface gold mining contributes to deforestation and land degradation in Ghana and Burkina Faso (West Africa). In addition, small-scale gold mining uses a technology for gold amalgamation that pollutes the environment with mercury (Hg) and adversely affects human health. In the framework of the recently started Mercury-AMF-project we aim to reduce the environmental damage caused by mercury used in gold mining in Ghana and Burkina Faso. This will be achieved by developing and implementing novel arbuscular mycorrhizal fungi (AMF) - plant systems as a strategy to reclaim mercury-contaminated sites. The cultivation of pioneer plants on contaminated soils can reduce the mercury pollution. Symbiotic mycorrhizal associations of those plants may strengthen the potential to remediate Hg-contaminated soils.

The implementation of the project is based on the following specific activities:

Characterization of the arbuscular mycorrhizal fungus (AMF) candidates in the soils of Ghana and Burkina Faso;

Development of prototype AMF plant systems as an innovative strategy for the remediation of Hg-contaminated sites;

Testing of mycophytoextraction methods to reduce the Hg soil concentration below threshold values;

Examination of the return of Hg-contaminated sites to agricultural use and the promotion of sustainable land management in gold mining regions;

Set-up of modelling approaches for the efficiency of mycophytoextraction methods and Hg plant uptake;

Exploration and communication of institutional and socio-economic framework conditions for the introduction of AMF plant systems.

During the first year of the project soil and plant sampling campaigns in Ghana and Burkina Faso were organised for screening the AMF-candidates capable for symbiosis with local plant species and tolerant to the mercury pollution. Clarification of possible mechanisms of phytoremediation is the next essential component of the research: several pathways of decontamination are possible including phytostabilization, phytovolatilization and phytoextraction. Based on the first results, field experimental trials with new AMF-plant systems will be established.
Geophysical mapping of soil texture variability in the root zone to improve modelling of the water and nutrient flow.
Authors: Madsen Kim Schwartz , Iversen Bo Vangsø , Børgesen Christen Duus
Published: March 2020

Modelling is often used to acquire information on water and nutrient fluxes within and out of the root zone. The models require detailed information on the spatial variability of soil hydraulic properties derived from soil texture and other soil characteristics using pedotransfer functions (PTFs). Soil texture can vary considerably within a field and is cumbersome and expensive to map in details using traditionally measurements in the laboratory. The electrical conductivity (EC) of the soil have shown to correlate with its textural composition.

This study investigates the ability of electromagnetic induction (EMI) methods to predict clay content in three soil layers of the root zone. As the clay fraction often is a main predictor in PTFs predicting soil hydraulic properties this parameter is of high interest. EMI and soil textural surveys on four Danish agricultural fields with varying textural composition were used. Sampling density varied between 0.5 and 38 points per hectare. The EMI data was gathered with a Dualem21 instrument with a sampling density 200-3000 points per hectare. The EC values were used together with the measured values of the clay content creating a statistical relationship between the two variables. Co-kriging of the clay content from the textural sampling points with the EC as auxiliary variable produces clay content maps of the fields. Unused (80%) texture points were used for validation. EMI-predicted clay content maps and clay content maps based on the survey were compared. The two sets of soil texture maps are used as predictors for PTF models to predict soil hydraulic properties as input in field-scale root zone modelling.

The comparisons between EC and clay content show some degree of correlation with an R2 in the range of 0.55 to 0.80 for the four fields. The field with the highest average clay content showed the best relationship between the two parameters. Co-kriging with EC decreased mean error by 0.016 to 0.52 and RMSE by 0.04 to 1.80 between observed and predicted clay maps.
Simulating snow instability in complex terrain
Authors: Richter Bettina , van Herwijnen Alec , Rotach Mathias W. , Schweizer Jürg
Published: March 2020

Numerical snow cover models are increasingly used in operational avalanche forecasting. While these models can provide snow stratigraphy and some snow instability information, their full potential is not yet exploited in forecasting. We investigated, how well the snow cover model Alpine3D simulated spatial and temporal variations in snow instability. Therefore, simulations were performed in highly varying complex terrain for the winter season 2016-2017 in the region of Davos, Switzerland for an area of about 21 km x 21 km. Alpine3D was forced with data from several automatic weather stations within the region, which were interpolated to a resolution of 100 m. To reproduce observed spatial variability, we scaled precipitation input with snow height measurements derived with airborne laser scanning. For comparison, we also simulated the snowpack without scaling. The simulation with scaling precipitation showed significantly higher spatial variability in modeled snow instability than the simulation without scaling. However, when information was aggregated to aspect and elevation dependent information for the whole region, as it is done for operational forecasting, this variability vanished and scaling precipitation seems unnecessary. At the beginning of the season and towards the end, snow instability depended on aspect, while in the winter months December to March, differences between different aspects were small. The simulations with scaling precipitation revealed a strong influence of snow depth on snow instability, although the various snow instability criteria provided inconsistent results. Simulated profiles, which were classified as rather favourable were rated as rather unstable and vice versa. A comparison to traditional snow profiles shows that snow stratigraphy was reproduced well, but assessing snow instability from stratigraphy alone is not feasible.
Planning for LOTOS: A New LOwer Troposphere Observing System
Authors: Hock Terry , Weckwerth Tammy , Oncley Steve , Brown William , Grubišić Vanda , Lee Wen-Chau
Published: March 2020

The National Center for Atmospheric Research Earth Observing Laboratory (EOL) proposes to develop the LOwer Troposphere Observing System (LOTOS), a new integrated sensor network that offers the potential for transformative understanding of the lower atmosphere and its coupling to the Earth's surface. 

 

The LOTOS sensor network is designed to allow simultaneous and coordinated sampling both vertically, through the atmospheric planetary boundary layer, and horizontally, across the surrounding landscape, focusing on the land-atmosphere interface and its coupling with the overlying free troposphere. The core of LOTOS will be a portable integrated network of up to five nodes, each consisting of a profiling suite of instruments surrounded by up to fifteen flux measuring towers. LOTOS will provide an integrated set of measurements needed to address outstanding scientific challenges related to processes within the atmospheric surface layer, boundary layer, and lower troposphere. LOTOS will also enable novel quantification of exchanges of biogeochemical and climate-relevant gases from microscale up to regional scale. 

 

LOTOS’ uniqueness lies in its ability to simultaneously sample both horizontally and vertically as an integrated system, but also in its flexibility to be easily relocated as a portable field-deployable system suitable for addressing a wide range of research needs. LOTOS will provide real-time data quality control, combine measurements from a variety of sensors into integrated data products, and provide real-time data displays. It is envisioned that LOTOS will become part of the deployable NSF Lower Atmosphere Observing Facilities (LAOF) and thus be available to a broad base of NSF users from both observational and modeling communities. LOTOS offers the potential for transformative understanding of the Earth and its atmosphere as a coupled system. This presentation will describe the background, motivation, plan, and timeline for the LOTOS’ proposed development.