bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil erosion in Austria – National calculations using regional data delivering local results for the ÖPUL programme
Authors: Schmaltz Elmar , Dersch Georg , Weinberger Christine , Krammer Carmen , Strauss Peter
Published: March 2020

Empirical models, such as the Revised Universal Soil Loss Equation (RUSLE) are in use since the 1950s to estimate the mean annual soil loss for single agricultural fields or spatially-distributed for larger areas (municipalities, regions or states). A particular focus on the computation of the RUSLE lies in the calculation of the respective factors on which the equation is built on and represent the erosivity of rainfall events, the erodibility of soils, the topography and land management. However, the RUSLE is highly susceptible to large errors in the prediction of the erosion rates of single agricultural parcels, due to the high variability of these factors in large areas (e.g. on national scale).

In this study, we present a parcel-sharp erosion map for the entire territory of Austria. We discuss frequent error sources of the factor computations and their consequences for the representativeness of erosion maps at nation-scale. Based on our results we discuss furthermore regional erosion hotspots and evaluate nationally funded management practices for soil erosion reduction as they are defined in the Austrian programme for an environmentally responsible agriculture (ÖPUL).

Since our approach depicts a novelty for Austria, we further describe opportunities for analysis of our results and highlight potential sources of errors, as well as regional and legal discrepancies of the distribution of national funds for soil conservation.
Long-term change monitoring of natural grasslands ecosystem in support of SDG 15.3.1
Authors: Tarantino Cristina , Adamo Maria , Blonda Palma
Published: March 2020

Assessing and maintaining the conservation of natural and semi-natural grassland ecosystems is one of the most important actions of the Biodiversity Strategy by the European Commission.

The present study focuses on the detection of long-term changes, from 1990 to 2018, of natural grasslands ecosystem, at local scale, in the “Murgia Alta”, a National Park as well as a Natura 2000 protected area, Southern Italy. The study site represents one of the largest areas for the conservation of such ecosystem in Italy. It is under pressure and in danger of destruction due to soil graining for agricultural intensification, illegal expansion of extraction sites, fires and land abandonment with consequent biodiversity loss.

Land Cover (LC) changes and class trends are one of the measures (sub-indicator) required for the implementation of the Sustainable Development Goals (SDG) 15.3.1 Indicator (“Proportion of land that is degraded over total land area”) of the Agenda 2030 by United Nations.

Multisource/multiresolution free available satellite data (visible, near infrared and short wave infrared spectral bands) were considered. Historical images from Landsat (4 images per year, one per season) were analyzed to produce different LC multiclass maps for 1990, 2001, 2004, 2011 and 2018 at 30 m spatial resolution, with an automatic data-driven classifier (Support Vector Machine). For 2018 Sentinel-2 data, 10 m spatial resolution, were also considered.

The mean value of the Overall Accuracies obtained for the LC maps from Landsat was 95%. Similar value was obtained in the last year from Sentinel-2.

Then natural grassland layer was extracted from those maps to analyze the trend of the grasslands ecosystem over time. The findings obtained indicate a total loss in the extension of the ecosystem of about 18% from 1990 to 2018. The major decrease (26%) occurred in 1990-2001. Then a modest decrease followed up to 2004 (year of institution of the National Park). Finally a slight increase probably due to land abandonment followed to fire events was quantified after 2004.

From the comparison of the different LC maps obtained, the decrease of natural grasslands resulted mainly due to transformation into agricultural areas.

In addition, these results are consistent with those obtained using Corine Land Cover maps available for the same period although at a coarser scale.

The SDG sub-indicator was evaluated inside the protected area and in a buffer, 10 km, area around. This sub-measure, which can be evaluated from time-series of satellite free data, can support long-term monitoring of protected area and can be used not only for the resilience evaluation of the study site to climate changes but also for the evaluation of conservation policies and as input to scenario modelling.
Urban preparedness for critical infrastructures disruptions from an end user perspective
Authors: Sandholz Simone , Sett Dominic
Published: March 2020

Critical infrastructures, such as energy, water and ICT supply are the backbone of societies. Especially in urban contexts, peoples’ dependency on the increasingly complex and interdependent network of critical infrastructures is daunting. However, a majority of inhabitants is rather unaware of related implications and risks, leaving individuals largely unprepared and highly vulnerable to potential critical infrastructure disruptions or failures. This is particularly true for developed countries with high supply security.

In addition, current discourses on safe and affordable operations of CI are mostly limited to the engineered part such as roads or electricity lines while hardly dealing with the soft components, namely coping capacities to overcome potential outages. With more frequent and intense occurrence of natural hazards the combination of CI complexity, dependency and unawareness poses a growing threat to urban populations with major implications for local disaster management actors and emergency services.

Based on comprehensive literature and policy analyses and this contribution will elaborate on challenges and opportunities of reducing natural hazards’ impacts on urban areas by extending assessments of critical infrastructure exposure to “soft” components, focusing on impacts on end users. Data from a major household survey conducted in a German city will be used to present and discuss damage impact types, their interlinkages as well as potential pathways towards risk reduction.
Determinants of Mollusk Abundance in Quaternary cores of Po Basin, Italy
Authors: Kowalewski Michał , Nawrot Rafał , Scarponi Daniele , Azzarone Michele
Published: March 2020

Absolute abundance of fossils observed in cores and outcrops can be governed by extrinsic processes (e.g., net accumulation rates, intensity of taphonomic processes, post-mortem transport), intrinsic determinants of shell production rates (e.g., fecundity, spawning frequency, growth patterns), or some combination of those interdependent factors. Understanding the role of drivers of fossil abundance can enhance stratigraphic and biological interpretations of the fossil record. To assess the importance of extrinsic and intrinsic processes for fossil mollusks, we used a total of over 400 samples (each representing a 10-cm core interval and ∼0.375 dm3 of sediment) derived from 12 cores from the late Quaternary sedimentary succession of the Po basin (Italy). The results indicate that although extrinsic factors such as compaction, net accumulation rates, and sequence stratigraphic context are to some degree controlling mollusk abundance in the cores, they cannot account for extremely shell-rich deposits. The results suggest instead that shell-rich core intervals record, primarily, episodes of high shell production rates. First, samples with very high shell density (> 4000 specimens per dm3) were characterized by extremely low evenness reflecting dominance by one super-abundant species, typically a small r-selective species capable of an explosive population growth (Lentidium mediterraneum and Ecrobia ventrosa). Second, a taphonomic test supported further the biological (R-hardparts model) rather than sedimentological (R-sediment model) origin of very dense shell concentrations: the quality of shell preservation correlates positively with shell density as predicted by R-hardparts model. The results suggest that intervals of high abundance of mollusk shells in cores record intervals of high biological productivity driven by opportunistic shelly species from lower trophic levels. Integrative studies of facies architecture, sequence stratigraphy, and paleontological data can help to differentiate biologically and physically produced fossil concentrations thus allowing for more informed ecological interpretations of the fossil record.
Environmental, biological and human drivers of the dieback of an evergreen Mediterranean forest
Authors: De Angelis Paolo , Liberati Dario , Giuliarelli Diego , Oreti Loredana , Vannini Andrea
Published: March 2020

Forests play a key role in the climate system thanks to their large carbon uptake and storage. On the other hand, forests are vulnerable to climate extremes and pest attacks, causing early tree mortality which in turn could reduce their carbon uptake capacity.

Early tree mortality is often associated to a complex interaction of predisposing stress factors (poor site quality, unfavourable stand conditions), inciting factors (frost, drought, mechanical damage) and contributing factors (fungi, insect borers).

In this context, the aim of the present work was to investigate the processes underlying the tree mortality observed in an evergreen mixed forest stand dominated by Quercus ilex, located in the Circeo National Park (central Italy).

The forest has the typical structure of an old-coppice not more managed (actual rotation time about 2 times that the normal), and was recently (2016) affected by an outbreak of Asian ambrosia beetle (Xylosandrus compactus) and Granulate ambrosia beetle (Xylosandrus crassiusculus) that caused an extensive trees crown browning. In 2019, plots were set in the area to monitor the beetle population dynamic and their impact on tree mortality. In each plot, species, dimension (DBH), stage of dieback, stem origin (resprouts after coppicing or from seed), presence of epicormic shoots and subcortical fungi stroma, were recorded for each woody plant.

The plot survey revealed a high frequency of stems classified in a declining stage or dead, on average 42% of the standing stems, with significant differences among the species: 97%, 85%, 74% and 47% for Arbutus unedo, Quercus ilex, Phyllirea latifolia and Fraxinus ornus respectively.

The higher stem mortality of Q. ilex was recorded in the smaller diameter classes, suggesting that the self-thinning process played an important role on the observed mortality as typical in the old not more managed coppices.

To disentangle the role of the interruption of the management from the climatic and biological drivers, time trends on NDVI index were constrained with the duration of the summer dry seasons and comparing our forest with similar Q. ilex forest coppices in the region and regularly managed.

Furthermore, the contribution of recent ambrosia beetles attack was assessed identifying the presence of twigs with signs of previous beetle attack on healthy, declining and dead plants.

Our findings point towards complex tree mortality dynamics, in which the competition generated by the stand abandonment predisposed the forest to the insect attack, leading to the general decline of the forest stand.
Offsets among ice core derived CO2 reconstructions covering the Holocene and Last Interglacial
Authors: Nehrbass-Ahles Christoph , Schmitt Jochen , Bereiter Bernhard , Eggleston Sarah , Mächler Lars , Silva Lucas , Stocker Thomas , Fischer Hubertus
Published: March 2020

There is a general consensus in the scientific community that Greenlandic ice cores do not allow for reconstruction of past atmospheric carbon dioxide (CO2) concentrations due to artifacts likely caused by in-situ production of excess CO2 from both organic and inorganic carbon compounds within the ice archive. In the case of Antarctic ice cores such processes are thought to be insignificant, making Antarctic ice cores the only direct archive of past atmospheric CO2 concentrations beyond modern observations. However, with increasing numbers of high-precision CO2 reconstructions from multiple Antarctic ice cores – mostly covering specific time intervals during the last 130 ka – it has become evident that offsets in CO2 are not unique to Greenland ice cores. Over the last decade evidence is mounting that small systematic offsets of typically 2-10 ppm exist among different Antarctic CO2 records covering the same time period. Because CO2 is well-mixed within the atmosphere different ice cores should agree with each other within their measurement uncertainty, independent of the ice core drilling site. The unambiguous detection of such offsets between different ice cores is only possible in the absence of strong atmospheric trends, such as during interglacial periods. Here, we take a closer look at CO2 offsets among records available for the Holocene and the Last Interglacial and investigate their long-term evolution. We present unpublished CO2 data from multiple ice cores, including Talos Dome and EPICA Dome C, and discuss possible offset producing mechanisms. We speculate that Antarctic ice cores are also subject to slowly progressing in-situ production of CO2 over many millennia, similar to Greenlandic ice cores, however to a much smaller extent and limited to about 10 ppm. We further note a tendency for higher offsets in the case of high accumulation sites. Despite all possible mechanisms that have the potential to alter CO2 concentrations within the ice archive, we highlight that the overall integrity of the ice core-based CO2 reconstruction is not in question, as all records generally share the same common signal. However, the absolute CO2 levels should be interpreted with care and in light of such potential offsets.
Large magnitude earthquakes of late Holocene age in the Precambrian of Finnmark, Northern Norway
Authors: Olesen Odleiv , Olsen Lars , Gibbons Steven , Kværna Tormod , Ruud Bent Ole , Johansen Tor Arne
Published: March 2020

The 80 km long Stuoragurra postglacial fault occurs within the c. 5 km wide Precambrian Mironjavri-Sværholt Fault Zone in the northern Fennoscandian Shield. Deep seismic profiling and drilling show that the fault dips at an angle of 30-40° to the southeast. The reverse fault can be traced down to a depth of c. 2.5 km on the reflection seismic profile. A total of c. 100 earthquakes has been registered along the fault between 1991 and 2019. Recordings at the ARCES seismic array in Karasjok c. 40 km to the SE of the fault and other seismic stations in northern Norway and Finland have been utilized. The maximum moment magnitude is 4.0. The Stuoragurra fault constitutes the Norwegian part of the larger Lapland province of postglacial faults extending southwards into northern Finland and northern Sweden. The formation of these faults has previously been associated with the deglaciation of the last inland ice. Trenching of different sections of the fault and radiocarbon dating of buried and deformed organic material reveal, however, a late Holocene age (between c. 700 and 4000 years before present at three separate fault segments). The reverse displacement of c. 9 m and segment lengths of 9-12 km of the two southernmost fault segments indicate a moment magnitude of c. 7. The results from this study indicate that the maximum magnitude of future earthquakes in Fennoscandia can be significantly larger than the existing estimate of c. 6.
Multidecadal changes in ENSO properties in the recharge oscillator conceptual model
Authors: Crespo Lander R. , Rodriguez-Fonseca Belen , Polo Irene , Keenlyside Noel , Dommenget Dietmar
Published: March 2020

We use a simple conceptual recharge oscillator model for the tropical Pacific to identify multidecadal changes in El Niño-Southern Oscillation (ENSO) statistics and dynamics during the observational record. The model, defined by only two variables, sea surface temperature (SST) and warm water volume (WWV), is fitted to the observations for the period 1901-2010. The variability of ENSO has increased during the 20th century. The model simulates similar changes in variance of SST and WWV. The cross-correlation between SST and WWV also shows significant changes during the observational record. From the 1970s onwards, both observations and model output show that the SST drives WWV anomalies with a lead-time of 10 months and the WWV feedbacks onto the SST with a lead-time of about 8 months. The latter is reminiscent of a recharge-discharge mechanism of the upper ocean heat content. Before the 1970s only the impact of SST on WWV, through implied wind changes, is observed and is reproduced by the model. The periodicity of ENSO has also changed; ENSO has become more frequent changing from a 7-yr periodicity in the beginning of 20th century to a 5-yr periodicity in the recent decades. We find that the full recharge-discharge mechanism of the equatorial upper ocean heat content that characterizes the dynamics of the ReOsc model is only observed from the 1970s onwards and is likely to be a consequence of a stronger observed coupling between WWV and SST and of the leading role of the thermocline feedback. The degrading quality in the observations for earlier periods can also partly explain the decadal changes in the ENSO interactions. We find that the Atlantic Multidecadal Variability and global warming can partly explain the observed and simulated multidecadal changes in ENSO properties.
Global distribution and temporal patterns of fire on peatlands
Authors: de Waard Farina , Barthelmes Alexandra , Joosten Hans
Published: March 2020

Peatland ecosystems provide critical ecosystem-services such as water and carbon storage and harbor unique biodiversity. Once ignited, peat fires may burn uncontrollably for weeks or months resulting in rapid ecosystem degradation and excessive CO2- Emissions. Despite the impact of peat fires on ecosystem services and climate, peatland fire regimes remain poorly characterized for many parts of the world. Here we investigate the global occurrence of peatland fires over the last two decades.

We estimate the global extent of peatland fires from 2009 to 2018 and identify drivers of variability and trends using a global peatland map (Global Peatland Database /Greifswald Mire Centre 2019), active fire detections from the Moderate Resolution imaging Spectroradiometer (MODIS), and several fire regime and climate anomaly-datasets. The data were used to delineate 14 ‘Peatland Fire Regions’ (PFR).

Our results indicate that between 2009 and 2018 globally 553,950 km² of peatland have been affected by fire (7.88 % of the global peatland area), whereas patterns and trends are widely differing. The extent of fire-affected area in the PFRs of Boreal North America and Boreal Eurasia both exceeded 80,000 km², which for both areas accounts for ~3.5 % of the peatland area. In the same time, over 120,000 km² were affected in both Central Asia and Equatorial Asia, i.e. ~23 % of their respective peatland area.

Northern peatlands are rather subject to natural fires and fire incidence is mostly driven by climate anomalies like droughts. Large peaks in fire occurrence in Boreal North America and Boreal Eurasia were correlated with higher temperatures and less rain. The strong linkage of inter-annual fire variability to temperature anomalies suggests that in these regions fire frequency and intensity may increase in future.

In tropical regions, particularly those of Africa and Asia, peatland fires tended to occur on degraded peatlands and fires occurred often multiple times on the same site during our study period. While inter-annual variability in fire occurrence was strongly determined by climate, the long term trends in these regions are dominated by human land management. In Africa the fire affected peatland area was rather constant over the years and fires had the highest return frequency, which reflects the widespread culture of burning in land reclamation and agriculture.

Southern/Equatorial Asia and to some extent South America showed peaks correlated with ENSO associated drought events, leading to the largest fire-affected peatland area in just one year in the Equatorial Asia region of 50,900 km² (in 2015).
Reactive nitrogen fluxes and scavenging patterns through sequential sampling over Mathura, India.
Authors: Chaturvedi Mudita , Kulshrestha Umesh
Published: March 2020

In recent years, reactive nitrogen concentration and potentiality has been of environmental concern. India being the second largest populated country in world, huge amount of NH3+ emissions are expected from various activities of humans, agriculture and individual sources. This work has been carried out to calculate wet deposition fluxes of Nr species in rain water and to understand their scavenging behaviour at a typical residential site under semiarid tropical region. For this purpose, sequential sampling of rain events has been performed for determining Nr levels during monsoon 2015 and 2016. Samples were analysed for reactive nitrogen species. The wet deposition flux was observed to be 2.13 kg ha-1year-1 for NH4+-N and 3.62 kg ha-1year-1 for NO3- -N in 2015. However, significant increase in NO3--N was observed in 2016 where as there was no remarkable change for NH4+. This clearly indicates towards dynamic behaviour pattern showing sources of reactive nitrogen in air over the region. Scavenging patterns confirmed the presence of NH4NO3 showing co-variations of NH4+ and NO3- along with the rainfall intensity. Thereby, confirming the possible forms in which these Nr species are being deposited over the study area.
Response of a coastal lagoon sediment budget to extreme events and climate change implications: The case of the Bay of Cadiz
Authors: LeBlanc Madeline , Plomaritis Theocharis , Lopez-Ruiz Alejandro
Published: March 2020

Climate change has resulted in increased storminess and sea-level change that affects the morphodynamics of bays worldwide, impacting both the ecosystem and local infrastructure. This study explores the impact of differing storm winds on the sediment budget of the Bay of Cadiz. The Bay of Cadiz is a highly altered coastal lagoon located in Southwest Spain surrounded by ports, navigation channels, and urban developments and is of high socioeconomic and environmental importance. The human interactions with the bay have already caused morphological impacts, which could be exacerbated by increased storminess. Potential impacts on the sediment budget of the Bay of Cadiz will be modeled using a Delft3D model previously calibrated and tested using field data from December 2011 to January 2012. The model will consider a variety of storm wind scenarios and observe their impacts on sediment transport within the bay, identifying sources and sinks. This will help to estimate the potential impacts of climate change and increased storminess on the bay and the surrounding areas.
Enabling and demonstrating SI traceability of ECVs and climate data records: the role of a national metrology institute
Authors: Fox Nigel , Green Paul , Nightingale Joanne , Woolliams Emma
Published: March 2020

The need for SI traceability to ensure integrity and trust in the Essential Climate Variables (ECVs) and the services and information derived from them, is well established. However, the means to achieve and demonstrate this in a universally-consistent manner globally and between variables, particularly for the complex bio-geophysical variables that make up many of the ECVs, is challenging.

 

National Physical Laboratory (NPL), the UK national metrology institute, has, over the last three decades, established a comprehensive research programme to extend traditional underpinning laboratory-based capabilities to meet the needs of a wide range of Earth Observation and climate applications. These have included:

both bespoke and tailored standards together with methods for the calibration of remote-sensing instruments (including pre-flight calibration of satellite sensors),

field measurements in the worlds Forests, Oceans, Deserts and the atmosphere

development of metrological methods to assess and describe uncertainties, end to end (sensor to user-relevant information)

most recently, extending to the development of a satellite to establish SI traceability from orbit as part of the ESA EarthWatch programme.

 

To build the necessary skills, capacity and trust within the community, NPL has established a close dialogue with EO/climate community experts and built international partnerships through active participation in international bodies such as CEOS & GEO. This has led to a close working relationship with ESA and other European national and international space agencies to provide metrological support across a wide range of projects.

 

This paper will discuss the criticality of SI traceability to providing trust in globally-relevant environmental & climate datasets and illustrate how it is being achieved through case studies, such as:

the ESA Fiducial Reference Measurement (FRM) projects,

establishment of SI-traceable reference test-sites for satellite calibration and validation

novel infrastructure to calibrate and characterise optical satellite sensors

and efforts to harmonise their in-flight radiometric gain.

 

NPL plays a lead role in the recently created European Metrology Network for Climate and Ocean and is keen to continue to ensure its efforts and research program address the priorities of the EO and climate community and will welcome input on future research directions.
Estimating the Vegetation phenology Time of recovery after a critical perturbation from Landsat time series within the frame of a Bayesian Harmonic model
Authors: vicario saverio , adamo Maria , tarantino Cristina , blonda palma
Published: March 2020

In Murgia Alta National Park the repeated fire perturb the stability of the environment and it s capacity to be a carbon sink. Thanks to the Landsat archive we can observed change in phenology t over the two decade (2000-2019). Unfortunately the phenological signal extracted from Landsat time series bear several uncertainties caused by missing data and error in atmospheric correction that makes difficult to reconstruct the trajectory of each pixel. Applying a Bayesian Harmonic model we can obtain not only expected values for the vegetation index time series but also confidence interval both for vegetation index and derived statistics. We took the phenological statistical framework of the Ecological Functional Attributes (EFA) to obtain annual statics and evaluate the time of recovery to obtain EFA with no statistical difference from the pre-perturbation time.

The results highlighted that only of subset of burned forest recover EFA values after 10 years of critical events. In particular the values of intra year variability tend to be higher due to the different trajectory of young shoots. The burned grassland time of recovery is much shorter given that the vast majority of pixel recover pre-event EFA in less than 4 year.
Decade of permafrost thaw in a subarctic palsa mire alters carbon fluxes without affecting net carbon balance
Authors: Olid Carolina , Klaminder Jonatan , Monteux Sylvain , Johansson Margareta , Dorrepaal Ellen
Published: March 2020

Snow depth increases observed in some artic regions and its insulations effects have led to a winter-warming of permafrost-containing peatlands. Permafrost thaw and the temperature-dependent decomposition of previously frozen carbon (C) is currently considered as one of the most important feedbacks between the artic and the global climate system. However, the magnitude of this feedback remains uncertain because winter effects are rarely integrated and predicted from mechanisms active in both surface (young) and thawing deep (old) peat layers.

Laboratory incubation studies of permafrost soils, in situ carbon flux measurements in ecosystem-scale permafrost thaw experiments, or measurements made across naturally degrading permafrost gradients have been used to improve our knowledge about the net effects of winter-warming in permafrost C storage. The results from these studies, however, are biased by imprecision in long-term (decadal to millennial) effects due to the short time scale of the experiments. Gradient studies may show longer-term responses but suffer from uncertainties because measurements are usually taken during the summer, thus ignoring the long cold season. The need for robust estimates of the long-term effect of permafrost thaw on the net C balance, which integrates year-round C fluxes sets the basis of this study.

Here, we quantified the effects of long-term in situ permafrost thaw in the net C balance of a permafrost-containing peatland subjected to a 10-years snow manipulation experiment. In short, we used a peat age modelling approach to quantify the effect of winter-warming on net ecosystem production as well as on the underlying changes in surface C inputs and losses along the whole peat continuum. Contrary to our hypothesis, winter-warming did not affect the net ecosystem production regardless of the increased old C losses. This minimum overall effect is due to the strong reduction on the young C losses from the upper active layer associated to the new water saturated conditions and the decline in bryophytes. Our findings highlight the need to incorporate long-term year-round responses in C fluxes when estimating the net effect of winter-warming on permafrost C storage. We also demonstrate that thaw-induced changes in moisture conditions and plant communities are key factors to predicting future climate change feedbacks between the artic soil C pool and the global climate system.
Towards a time-gated Raman spectrometer with VIS-NIR SPAD camera for stand-off planetary surface exploration
Authors: Ciaffoni Luca , Matousek Pavel , Sedgwick Iain , Waltham Nick
Published: March 2020

Single-photon avalanche diode (SPAD) arrays are solid-state detectors that offer imaging capabilities at the level of individual photons. Very recently, time-gated cameras based on solid-state CMOS SPAD technology have been proposed for improving the performance and field applicability of Raman spectrometers for on-surface planetary geoscience through addressing the largely unmet challenge of suppression of fluorescence interference in highly fluorescent rocks (e.g. minerals containing phosphate, one of the chemical nutrients thought to be essential for life).

The effectiveness of Raman SPAD cameras currently proposed in the literature, however, is at present restricted to a small subset of samples and regimes of operations. This is largely owed to two main limitations. Firstly, their performance is optimised only for the VIS spectral region (typically around 532 nm), where the fluorescence issue tends to be exacerbated due to increased likelihood of electronic excitation for most molecular species compared to Raman excitation above 775 nm. Secondly, their 2D architecture is limited to few pixel rows, which reduces their light-gathering capability and consequently the detection performance of the Raman spectrometer.

We present the preliminary work towards the development of a novel time-gated Raman spectrometer that relies on a large format NIR-optimised SPAD camera prototype with time resolution better than 200 ps. This technology promises to deliver unsurpassed dual-wavelength Raman detection capabilities that would be transformative for stand-off sample analysis in surface exploration of Mars and Icy moons.

A performance analysis model for predicting the fluorescence and ambient light suppression performance levels in relation to the properties of various samples, environmental conditions and specifications of the laser and camera is presented, followed by the preliminary designs of the SPAD camera module and Raman spectrometer.
ACTRIS efforts for Sentinel 5 Precursor validation
Authors: Mona Lucia , Papagiannopoulus Nikolaos , Pappalardo Gelsomina , Wandinger Ulla , D'Amico Giuseppe , Amiridis Vassilis , Arboledas Lucas-Alados , Nicolae Doina , Apituley Arnoud , O'Connor Ewan , Pressler Jana
Published: March 2020

The Sentinel 5 Precursor products, call for an accurate validation. Europe can be nowadays regarded as a leader in ground-based vertical profiling observations. ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) is an EC funded infrastructure integrating European ground-based stations equipped with advanced atmospheric equipment. Among these, EARLINET (European Aerosol Research Lidar NETwork) and Cloudnet are well-established networks providing vertical profiles of aerosol and clouds with high vertical and temporal resolution. A network of ground-based stations has the ability to provide the spatio-temporal development of aerosol and cloud fields and offers a unique opportunity for the validation of observations from space. In this project, state-of-the-art instrumentations for observing aerosol and clouds will be used for validation purposes: multi-wavelength lidar (EARLINET) and Doppler cloud radar (Cloudnet).

Characterization of aerosol and cloud fields over the stations is provided by the use of EARLINET and Cloudnet data. Additional information is provided by AERONET data where available. Differences will be reported as a function of aerosol load, aerosol and cloud height, aerosol type, cloud type and underneath surface.

First results of validation efforts performed within ACTRIS in terms of a quantitative evaluation of the accuracy of S5P aerosol and cloud products will be reported. This activity is done under the EC-ACTS: Earlinet and Cloudnet - Aerosol and Clouds Teams for Sentinel-5P Validation unfunded project, which comprises 3 EARLINET/Cloudnet stations [Potenza (IT), Leipzig (DE) and Cabauw (NL)]; 3 EARLINET stations [Granada (ES), Athens (GR) and Bucharest (RO)] and 2 Cloudnet sites [Mace Head (IE) and Sodankylä (FI)].

In particular, the first results will be about the S5P Aerosol Layer Height (mandatory product) and Aerosol Optical Depth (optional product) and whenever available the AAI-based columnar Aerosol Type product.
The challenge of sensor selection, long term-sensor operation and data evaluation in inter- -institutional long term monitoring projects (lessons learned in the MOSES project)
Authors: Fischer Philipp , Friedrich Madlen , Brand Markus , Koedel Uta , Dietrich Peter , Brix Holger , Kerschke Dorit , Bussmann Ingeborg
Published: March 2020

Measuring environmental variables over longer times in coastal marine environments is a challenge in regard to sensor maintenance and data processing of continuously produced comprehensive datasets. In the project “MOSES” (Modular Observation Solutions for Earth Systems), this procedure became even more complicated because seven large Helmholtz centers from the research field Earth and Environment (E&E) within the framework of the German Ministery of Educatiopn and Research (BMBF) work together to design and construct a large scale monitoring network across earth compartments to study the effects of short-term events on long term environmental trends. This requires the development of robust and standardized automated data acquisition and processing routines, to ensure reliable, accure and precise data.

Here, the results of two intercomparison workshops on senor accuracy and precicion for selected environmental variables are presented. Environmental sensors which were to be used in MOSES campaigns on hydrological extremes (floods and draughts) in the Elbe catchment and the adjacent coastal areas in the North Sea in 2019 to 2020 were compared for selected parameters (temperature, salinity, chlorophyll-A, turbidity and methane) in the same experimentally controlled water body, assuming that all sensors provide comparable data. Results were analyzed with respect to individual sensor accuracy and precision related to an “assumed” real value as well as with respect to a cost versus accuracy/precision index for measuring specific environmental data. The results show, that accuracy and precision of sensors do not necessarily correlate with the price of the sensors and that low cost sensors may provide the same or even higher accuracy and precision values as even the highest price sensor types.
Downscaling of L-Band microwave using Sentinel-3 land surface temperature
Authors: Al Bitar Ahmad , Ojha Nitu , Corbari Chiara , Merlin Olivier , Kerr Yann , Mancini Marco
Published: March 2020

Downscaling of L-Band microwave using Sentinel-3 land surface temperature

A large number of agricultural and water management applications require sub-kilometric frequent revisit surface Soil Moisture (SM) observations. L-band passive radiometer acquisitions are especially suited for soil moisture retrieval since they are less susceptible to attenuation by vegetation than active methods and are less sensitive to surface roughness than C or X – bands. However, while providing a 3 days global coverage for ascending and descending orbits with the currently available missions (SMOS/SMAP) the spatial resolution of the space-borne L-band radiometers is of ~40 km. Downscaling technics have been extensively used to increase the resolution of the SM products by combining data from optical (Merlin et al. 2012) and SAR sensors (Tomer et al. 2015). Here, we use land surface temperature data from the Sentinel-3 sensors to disaggregate the SMOS SM product into the DISPATCH algorithm. DISPATCH is based on the link between the evaporative efficiency and the SM (Merlin et al. 2010). The exercices is applied over Italy and compared to in-situ SM observations and model outputs over two sites in Northern and southrn Italy (Chiese and Capitanata). The algorithm is run using  MODIS and the Sentinel-3 data for a comparative results. The potential of the combined use of Sentienl-3/MODIS and SMOS/SMAP is also investigate. The current study extends the application of an existing algorithm to new operational data from the Copernicus programe while accessing the advantages and ceavates. 
Latitudinal distributions of 234Th in the upper western Indian Ocean
Authors: Kim Suk Hyun , Kim Intae , Lee Hyunmi
Published: March 2020

We conducted an onboard measurement of dissolved- and particulate 234Th in seawater of upper Indian Ocean. The study region covers the meridional section of upper (<500 m depth) Indian Ocean (3⁰N to 15⁰S at 67⁰E in July 2017, and 5⁰S to 13⁰S at 60⁰E and 5⁰S to 24⁰S 67⁰E in April 2018). Dissolved and particulate (>1.2 μm) 234Th ranged 0.8 – 2.7 dpm L-1 and 0.05 – 0.7 dpm L-1, respectively. In July 2017, the large deficiency of dissolved 234Th were consistently observed at ~50m depth where the subsurface chlorophyll maximum (SCM) present, along the entire section (5⁰S to 13⁰S). After then, the 234Th/238U were almost ~1 in ≥100 m depths. In contrast, in April 2018, the significant deficits of dissolved 234Th were observed in entire upper water columns, 0 – 200m depths. This difference in distribution patterns between two years appears to be related to the annual-/seasonal- variations of SCM patterns. In 2018, SCM were shown in 70 – 80 m depths near equator (5⁰S degree), and gradually deepens in lower latitude (SCM presents in 130 m depths in 24⁰S). Interestingly, the unusually lowest dissolved 234Th (and very low particulate 234Th also,) were observed in 5⁰S 60⁰E, near the Seychelles–Chagos thermocline ridge (SCTR) region. There are two hypotheses to explain this extremely lower concentrations of 234Th. The one is that the large input of lithogenic particles from SCTR, seems to be due to largest 234Th removal in the water column of extremely shallow area (<300 m of bottom depth). The other is that unusually strong eastward currents (>1 m/s of zonal velocity, based on ADCP observations) can laterally transport the 234Th. In this presentation, we will also present the preliminary results of vertical export fluxes of some particulate trace elements (Al, Fe, Mn, Cu, Zn, Ni, Pb, and etc.) in the upper Indian Ocean estimated by using this 234Th tracer.
Investigating the Earthquake Cycle along Marmara Sea Region of North Anatolian Fault by means of seismo-geodetic observations
Authors: Ozener Haluk , Aktug Bahadir , Yilmaz Onur , Sabuncu Asli , Gelin Bengisu , Uçan Kaan Alper , Turgut Bulent , Batur Maryna
Published: March 2020

Since 1766, the North Anatolian Fault Zone in the Marmara Sea has not generated a Mw=7.0 earthquake. In the Marmara Sea, three different segments are located having ~25 mm slip rates and ~10 mm slip deficit per year. The faulting mechanism within the Marmara Sea has capability of generating earthquakes larger than Mw7.0. We are continuously monitoring this critical region with more than 30 seismo-geodetic stations equipped with 100 Hz sampling seismographs and 1 Hz sampling GPS receivers, in order to detect fast and slow tectonic motions in and around the Marmara Sea at temporal and spatial scale from milliseconds to years and from centimeters to tens of kilometers.

The data obtained during this study provides us to identify the slip deficit along the fault, the segmentation of fault, the interaction between slip-deficit and background seismicity. Besides, these data also contribute to identify the pre-seismic seismo-geodetic behavior and co-seismic slip when Mw=7.0 type of earthquakes occurs.
Unexpected segregation patterns in high speed granular flows
Authors: Valance Alexandre , Delannay Renaud , Neveu Aurelien
Published: March 2020

Classically, for free surface flows of binary granular mixture, large particles migrate at the top of the flow while small ones percolate to the bottom. The key mechanisms at the origin of this segregation behavior have been identified as a combination of squeeze expulsion and kinetic sieving (Savage & Lun J. Fluid Mech. 1988). In this case, the segregation process is governed by the gravity. We discovered here by means of numerical simulations a new segregation pattern in high speed granular flows where size segregation is driven mostly by granular temperature gradients rather than gravity, which highlight the complexity of providing a complete description of segregation processes.

High speed granular flows are obtained by means of discrete numerical simulations (DEM) in a confined geometry with lateral frictional side-walls. Recently, Brodu et al. (Phys. Rev. E 2013, J. Fluid Mech. 2015) highlighted that this confined geometry allows to produce steady and fully-developed flows at relatively high angles of inclination, including a rich and broad variety of new regimes. In particular, they showed the existence of supported regimes, characterized by a dense and cold (in terms of granular temperature) core floating over a dilute and highly agitated layer of grains, accompanied with longitudinal convection rolls.

We performed extensive numerical simulations within this geometry with binary mixture of spheres with a given size ratio of 2. We analyzed segregation patterns of steady and fully-developed flows for inclination angles ranging from 18° to 50° and various mixture proportions of large particles ranging from 0 to 100%. We evidenced a new segregation pattern that emerge in the supported flow regimes: large particles no longer accumulate in the upper layers of the flow but are trapped in the dense core and localized at the center of the convection rolls. The strong temperature gradients that develop between the dense core and the surrounding dilute layer seem to govern the segregation mechanism. The accumulation of large particles in the dense core, which is the fastest region of the flow, also tends to enhance the total mass flux in comparison with similar mono-disperse flows.
Airborne mapping and in situ validation of European land surface temperature using the NASA-JPL HyTES sensor. Results from the 2019 European NET-Sense Campaign in support of the Copernicus High Priority Candidate satellite mission development.
Authors: Wooster Martin , Johnson James , Dowling Tom , de Jong Mark , Grosvenor Mark , Langsdale Mary , Hook Simon , Eng Bjorn , Johnson William , Rivera Gerardo , Hulley Glynn , Schüttemeyer Dirk , Koetz Benjamin
Published: March 2020

The NASA ESA Temperature Sensing Experiment (NET-Sense) is a NASA and ESA funded campaign in support of the Copernicus Land Surface Temperature Monitoring (LSTM) satellite mission.

The LSTM mission would carry a calibrated, high spatial-temporal resolution thermal infrared imager whose data would be used to provide the land-surface temperature information required for such applications as evapotranspiration estimation at the European field-scale. The LSTM mission responds to priority requirements of the agricultural user community for improving sustainable agricultural productivity in a world of increasing water scarcity and variability.

As part of the effort to LSTM mission development effort, the first non-US flights of NASA JPL’s state-of-the-art Hyperspectral Thermal Emission Spectrometer (HyTES) were conducted on a UK research aircraft in both the UK and Italy in June and July 2019. HyTES is an airborne thermal hyperspectral imager providing extremely high quality and radiometrically precise infrared radiances within 256 spectral channels across the spectral range 7.5 to 12 µm, with the primary aim to map LST and surface spectral emissivity. Flights in Italy were accompanied by the HyPLANT and TASI instruments, operated by FZ-Juelich, Germany installed aboard a second aircraft from CzechGlobe (CZ).

We provide an overview of the NET-Sense campaign, example results from HyTES and comparisons to in situ LST and surface spectral emissivity data collected co-incident with the aircraft overflights using tower-mounted radiometers and portable FTIR spectrometers adapted for the purpose. We explain the integration of NET-Sense into the broader science strategy for the LSTM mission, and highlight planned activities for the coming years, including NET-Sense 2020 European campaign plans.
Simultaneous detection of lightning flashes by MMIA-ASIM and Colombia Lightning Mapping Array
Authors: López Jesús Alberto , Montanyà Joan , van der Velde Oscar , Fabró Ferran , Navarro Javier , Reglero Víctor , Chanrion Olivier , Neubert Torsten , Dimitriadou Krystallia , Østgaard Nikolai
Published: March 2020

Since April 2018, the Atmosphere-Space Interactions Monitor (ASIM) has been in operation on board the International Space Station (ISS). ASIM is composed of the Modular X-and Gamma Ray Sensor (MXGS) as well as a multispectral and high resolution array of photometers and cameras, called the Modular Multispectral Imaging Array (MMIA). These instruments allow us to investigate Terrestrial Gamma-Flashes, Transient Luminous Events and their interactions with thunderstorms and lightning flashes.

The Colombia Lightning Mapping Array (COL-LMA), operational since 2017, is the first VHF range network installed and working in a tropical region, and can contribute to the electrical understanding of thunderstorms and lightning leader processes associated with high energy phenomena in the upper atmosphere.

This work employs data from the MMIA array to investigate optical emission patterns at different bands (337 nm, 180-230 nm and 777.4 nm) caused by lightning leader development and cloud-to-ground flashes, derived from the COL-LMA and LINET network respectively. All cases are also correlated with optical observation from the Lightning Imaging Sensor (LIS) on board the ISS, and the Geostationary Lightning Mapper sensor on the GOES-R satellite.

The region of study is defined by the high detection-efficiency area of the COL-LMA around the Magdalena river valley. MMIA-ASIM information since July 2019 corresponding to passes over this tropical region has been analysed.