bluuebunny/crossref_metadata_2025 huggingface dataset:
Clarify the dependency of controlling factors in DOC transport in small mountainous rivers by redundancy analysis
Authors: Liu En-Ru , Shih Yu-Ting , Lee Li-Chin
Published: March 2020

Dissolved organic carbon (DOC) serves as one of the major energy sources in aquatic ecosystems, which is an important pathway connecting terrestrial and marine carbon reservoirs. DOC transport at catchment scale is recognized as being regulated by runoff, slope, soil organic carbon (SOC), biome, and wetland proportion; however, the controls in subtropical small mountainous rivers (SMRs) is rarely discovered before. This study investigated DOC export in 19 catchments in northern Taiwan supplemented with landscape and land use dataset to characterize the controlling factors of DOC transport. Meanwhile, the principle component analysis (PCA) and redundancy analysis (RDA) are applied to untangle the dependence of the controlling factors. Results showed that DOC concentration in Taiwan is very low at approx. 0.8 mg L-1, yet the annual DOC yields of the 19 catchments is around 25.23 kg ha-1 yr-1, which is much higher than the global mean (14.4–19.3 kg-C ha-1 yr-1). PCA and RDA shows that the human activities and landscape can explain 87% and 77% of the explained variance, yet runoff play an independent role in DOC transport.  Excluding the overlap, human activities and landscape only accounts for 15 % and 5% of the explained variance, respectively. The overlap between the two components are as high as 72%, indicating the two components could not be separated subjectively. Conclusively, DOC export is mostly dominated by human activities and landscape together, which suggests that they should be considered simultaneously. Besides, DOC yield is positively correlated with streamflow and SOC, but negatively correlated with slope gradient. Our study suggests that interpretation of spatial variation in DOC export should address the overlap between human activities and landscape, which can help predicting the ungauged catchments in catchment management.
Drone based visual inspections, Infrared Thermography investigations and GPR surveys of the Roman masonry bridge Ponte Lucano, Tivoli, Italy
Authors: Ludeno Giovanni , Biscarini Chiara , Catapano Ilaria , Cavalagli Nicola , Pepe Francesco Ascanio , Ubertini Filippo
Published: March 2020

The objective of this study is to evaluate the cooperative use of non-destructive contactless diagnostic technologies as a tool to enhance the amount of information useful to assess historical assets’ structural and material degradation. The case study regards the Ponte Lucano structure in Tivoli (Italy) a Roman bridge located along the Aniene River, the largest tributary of the Tiber. It can be considered as an emblematic iconic structure in synthetizing the needs of structural consolidation and monument conservation. The bridge is, indeed, affected by hydraulic risk due to the floods of Aniene river.

Unmanned aerial (UAV) 3D photogrammetric surveys were carried out to perform visual inspections accounting for those bridge portions that are difficult to be reached directly. Hence, infrared thermography (IRT) and ground penetrating radar (GPR) surveys were considered as complementary technologies useful to obtain information about surface and subsurface structural features [1], [2]. The IRT analysis w characterized the thermal profile of the bridge and detected its most humid parts. The GPR investigations were performed to improve knowledge of the bridge subsurface structure.

The results of the analysis demonstrate that, the integration of mentioned diagnostic tools, provide information about the degradation state of the stones and its causes, as well as regarding the evolution of the structure from its construction up to the present configurations. In particular, UAV 3D photogrammetry allowed a very detailed digital map of the bridge, covering almost every part of the structure and revealing precious informations, among which chromatic properties and size characteristics of the bridge areas which are not directly accessible by a human operator. IRT results corroborated the hypothesis that the present degradation condition of the Ponte Lucano is mainly a result of the water retention within its materials. GPR images, provided information about the internal stratification of the materials of the bridge and allowed the localization of two buried arch structures, allegedly located in the northern bank and at the Plautii Mausoleum, whose presence confirms the historical-bibliographical hypothesis about the bridge building processes.

[1] Meola, C. Infrared thermography of masonry structures. Infrared Physics and Technology 2007; 49(3 SPEC. ISS.), 228-233.

[2] Daniels D.J. Ground Penetrating Radar. In IEE Radar, Sonar and Navigation Series 15; IEE: London, UK, 2004.
Climatic imprint in the mechanical properties of ice sheets and its effect on ice flow: Observations from South Pole and EPICA Dome C ice cores
Authors: Martin Carlos , Conway Howard , Koutnik Michelle , Ritz Catherine , Bauska Thomas , Drews Reinhard , Ershadi M. Reza
Published: March 2020

The climatic conditions over ice sheets at the time of snow deposition and compaction imprint distinctive crystallographic properties to the resulting ice. As the snow gets buried, its macroscopic structure evolves due to vertical compression but retains traces of the climatic imprint that generate distinctive mechanical, thermal and optical properties. Because climate alternates between glaciar periods, that are colder and dustier, and interglacial periods, the ice sheets are composed from layers with alternating mechanical properties. Here we compare ice core dust content and crystal orientation fabrics, from the ice core records, with englacial vertical strain-rates, measured with a phase-sensitive radar (ApRES), at South Pole and EPICA Dome C ice cores. Similarly to previous observations, we show that ice deposited during glacial periods develops stronger crystal orientation fabrics. In addition, we show that ice deposited during glacial periods is harder to vertically compress and horizontally extend, up to about 3 times, but softer to shear. These variations in mechanical properties are typically ignored in ice-flow modelling but they could be critical to interpret ice core records. Also, we show that the changes in crystal orientation fabrics due to transitions from interglacial to glacial conditions can be detected by phase-sensitive radar. This information can be used to constrain age-depth in future ice-core locations.
On the determination of low degree harmonics by combining SLR with GRACE / GRACE-FO
Authors: Koenig Rolf , Schreiner Patrick , Dahle Christoph
Published: March 2020

Today's state-of-the-art gravity missions GRACE and GRACE-FO monitor the Earth's gravitational field in high temporal and spatial resolution. The resulting time series of gravitational fields serves various geophysical applications. It is however recommended to replace the C(2,0) coefficients, which describe the change of the Earth's oblateness, by those determined by Satellite Laser Ranging (SLR) to geodetic satellites. There are also discussions ongoing on the C(2,1), S(2,1) and C(3,0) coefficients. Current research shows that a combination of GRACE and GRACE-FO with SLR can lead to an improvement of the determination of the low degree coefficients in view of certain geophysical applications. This contribution gives an insight into the recent research at the Helmholtz Center Potsdam - German Research Center for Geosciences (GFZ) on various methods for the multi-technique combination on normal equation level and discusses the effects on the low degree spherical harmonics.
Integrated geophysical imaging of a solid waste landfill (Greater London, UK)
Authors: Watlet Arnaud , Inauen Cornelia , Dashwood Ben , Whiteley Jim , Creusel Tiphanie , Isunza Manrique Itzel , Caterina David , Scott Duncan , Chambers Jonathan
Published: March 2020

In recent years, increased pressure on land use has underscored the need for characterisation of waste composition and distribution in old landfills. In some cases, a lack of information about waste types and potential leachate migration may also pose risks to the environment. Additionally, the emerging potential for retrieving raw materials from old landfills via enhanced landfill mining has further driven the need for developing better informed landfill inventories. Characterising landfills traditionally relies on two main sources of information: historical reports and ground truth data. However, historical reports on old landfills are not always available or are often incomplete, and relying only on ground truth data (drilling or trenching) is costly and requires extrapolation of, and interpolation between, sparse point-data. Geophysical techniques provide an additional, complementary way for characterising landfills, and a means of non-invasively gathering volumetric information on large portions of the surveyed area. Although, in many cases, the complexity and heterogeneity of the internal structure of the landfill makes it difficult to rely on measurements of one single geophysical property alone.

Here, we present an integrated geophysical survey conducted at a landfill site in the Greater London area. The site consists of a former sand, gravel and clay quarry, which was utilised as a solid waste landfill from the 1940s. The landfill was progressively filled with domestic and commercial waste, reaching a peak in activity in the late 1960s and 1970s. Since the landfill has ceased to operate, the site is now relatively flat, covered by grass and used for horse grazing. Our geophysical campaign comprised a combination of several geophysical techniques including rapid mapping (Electromagnetic Induction, EMI; Magnetometry) and profiling techniques (Electrical Resistivity Tomography, ERT; Induced Polarization; IP; Multichannel Analysis of Surface Waves, MASW). The results show a strong contrast in geophysical character between the eastern and the western side of the surveyed area, attributed to a significant change in waste composition. The geophysical results are compared with two intrusive sampling campaigns comprising a series of boreholes, trial pits and Cone Penetration Tests (CPT). Correlating these ground truth data with the geophysical results allows the identification of different geophysical properties related to distinct waste types, from which it is possible to outline zones of similar waste composition within the landfill site.
INTEGRATION OF GNSS-GPS NETWORKS (cGPS) FOR OBTAINING STRESS AND STRAIN MODELS FOR THE SPINA REGION (SOUTH OF THE IBERIAN PENINSULA AND NORTH AFRICA)
Authors: Pérez-Peña Alejandro , Fernández-Ros Alberto , Rosado Belen , De Gil Amós , Prates Gonzalo , Garate Jorge , Berrocoso Manuel
Published: March 2020

Nowadays, both, the number of observations and the accuracy of satellite-based geodesic measurements, like GNSS, have increased. Therefore, GNSS provides more data as displacement values and velocities. This paper demonstrates that GNSS data analysis is a powerful tool to study geodynamic processes.

In this study, the analyzed GNSS data correspond to continuously recorded GPS (CGPS) stations, what we call the SPINA network. These stations are located in a region called Ibero-Maghrebian which includes the southern areas of the Iberian Peninsula and northern Africa.

The CGPS stations are included in the following organizations: RENEP (National Network of Permanent Stations), RAP (Andalusian Positioning Network), the Murcia Region CGPS Networks, ERVA (Valencian Reference Stations Network), IGN (National Geographic Institute) and the network TOPOIBERIA. The velocity was obtained in two steps: (1) preprocessing position time-series data of daily GPS measurements and (2) applying a combined model using the weighted least-squares method.

The prior knowledge of the crustal strain rate tensor provides a description of geodynamic processes such as the fault strain accumulation.

Based on the distribution of the GNSS stations, several grid sizes were tested to identify the best resolution. A Python script was used to compute the full two-dimensional velocity gradient tensor by means of inverting the GNSS velocities. The tensorial analysis provides different aspects of deformation, such as the maximum shear strain rate, including its direction, and the dilatation strain rate. These parameters can be used to characterize the mechanism of the current deformation.

Based on the computations from the GNSS-data model of components of horizontal deformations, the rates of both principal, values and axes, of the Earth’s crust deformation were found. Deformations measured in the Ibero-Maghrebian region with GPS could be interpreted in terms of either elastic loading or ductile deformation.
Laboratory experiments for analysing the impact of herbaceous vegetation on riverbank erosion
Authors: Toth Elena , Guerrero Massimo , Gragnano Carmine Gerardo , Domeneghetti Alessio , D'Agostino Daniela
Published: March 2020

Planting of herbaceous vegetation on riverbanks is a measure for reducing river flooding occurrence, through the protection of the bank face from fluvial erosion. In fact, mitigating the erosive action of the water flow and improving soil resistance by increasing the strength of the bank material with their roots, such nature-based solution reduces the risk of local and shallow instability mechanisms that may lead to the collapse of levees and riverbanks during flood events.

While there is nowadays a wide experience on the use of vegetation over hill slopes and other ‘mainly dry’ soil conditions, a carefully calibrated design approach to understand the vegetation impact inside the river bed and banks, under flood flow forcing, represents a much less explored research field, which is investigated in the Open Air Lab-Italy in the EU H2020 project OPERANDUM. To address this important and complex problem, a combined use of laboratory experiments, site monitoring and numerical analysis is required to improve actual procedures and standards.

In the present work, the principal focus is on the design, preparation and deployment of the laboratory activities, extremely rare in the literature, with a discussion on the first experimental findings and observations. A set of experiments in a recirculating, tilting hydraulic flume are designed and implemented, in order to gain, in a controlled environment, information on the influence of the vegetation on both hydraulic and erosive processes.

During the experimental tests, water flow depth and velocity are monitored through UPV Ultrasound Velocity Profilers and Particle Tracking Velocimetry, in order to estimate the tangential stress at the soil-water interface. The main challenge resulted to be the estimation of the volumes of soil eroded during the experiments, due to the very limited quantities that are eroded and to the particularly fine-grained texture of the soil (that was collected from a real embankment of the river Panaro, reference case for the Open Air Lab).

The laboratory experiments allowed to compare the impact of different flow regimes (varying the channel slope, different flow velocity fields were tested) over soils vegetated with both shallow-rooted and deep-rooted perennial herbaceous species, and the results will successively help to analyse the hydraulic and erosive processes on the riverbanks, where such vegetation cover will be installed.
Investigating mantle melting temperatures on Earth, Mars and the Moon using Al-in-olivine thermometry
Authors: Jennings Eleanor , Buisman Iris , Coull Peter
Published: March 2020

Al-in-olivine thermometry, based upon the temperature-dependent solubility of Al in the olivine crystal structure [1], has become a widely adopted method to investigate the crystallisation temperatures of primitive mantle melts on Earth [2]. The thermometer is calibrated using the Al contents of co-existing olivine and spinel: these phases are on or near the liquidus of primitive magmas, so the thermometer should access liquidus temperatures of mantle melts, thereby constraining the minimum mantle melting temperature. CFB-associated primitive melts have average olivine crystallisation temperatures well in excess of MORB, and back-calculation to the potential temperature of their mantle source regions suggests mantle thermal anomalies of several hundred degrees [3].

Whilst mantle thermal anomalies are moderately well-understood on Earth, relatively little is known about the melting conditions in the mantles of the Moon and Mars that led to the production of Maria basalts and Martian surface basalts and associated volcanic activity. Several samples returned from the Moon and basaltic meteorites from Mars (shergottites) are primitive and rich in both olivine and spinel, so would appear ideal samples for the application of Al-in-olivine thermometry to unravel their respective mantle melting conditions and, more generally, the thermal structures of those planetary interiors. In this study, we present preliminary investigations into a) five Apollo 12 primitive lunar basalts, and b) two olivine-phyric shergottites. We find that pervasive shock features make the trace Al concentrations of shergottitic olivines difficult to use, because high Al concentrations are associated with a fine micron to sub-micron network of K-rich melt veins, suggestive of fluid-mediated melt transport. On the other hand, olivine phenocrysts in all five lunar samples yield clear trends in Al contents and are excellent targets for Al-in-olivine studies. We present preliminary thermal results, as well as a newly-calibrated set of relevant thermodynamic parameters needed for back-calculating lunar melting temperatures. A fully quantitative assessment of lunar maria liquidus temperatures is, however, currently hampered by the limited calibration range of the Al-in-olivine thermometer and the unconstrained effect of high spinel TiO2 contents on the results.

[1] Coogan, L. A., Saunders, A. D. & Wilson, R. N. Chem. Geol. 368, 1–10 (2014).

[2] Trela, J. et al. Nat. Geosci. 10, 451–456 (2017).

[3] Jennings, E. S., Gibson, S. A. & Maclennan, J. Chem. Geol. 529, 119287 (2019).
Last Glacial multi-decadal to millennial-scale precipitation variability inferred from Puerto Rican speleothems
Authors: Warken Sophie , Vieten Rolf , Winter Amos , Spötl Christoph , Miller Thomas , Frank Norbert , Jochum Klaus Peter , Mielke Aaron , Schandl Jonas , Schröder-Ritzrau Andrea , Mangini Augusto , Scholz Denis
Published: March 2020

The high sensitivity of climate variability to the mean position of the intertropical convergence zone at different time scales is well known. However, due to a lack of absolutely dated high-resolution proxy records, the long-term changes in the tropical Atlantic oceanic and atmospheric circulation system prior to the late Holocene are still not well constrained. Paleo climate reconstructions and model studies suggest a very complex response of the northern hemispheric tropical rain belts in the western tropical Atlantic depending on the nature of the forcing, surface type and surrounding continent-ocean configuration.

Here we present a high resolution multi-proxy speleothem record from Cueva Larga (Puerto Rico) covering the last Glacial between 46 and 15 ka BP. Precise 230Th/U-dating reveals growth rates between 50 up to more than 1000 µm/year which allow for the investigation of multi-decadal to millennial scale variability in the stable isotope (δ18O and δ13C) and elemental records.

The analysed proxies document a pronounced response of regional precipitation to abrupt centennial to millennial scale climatic excursions across the last Glacial, such as Heinrich Stadials and Dansgaard/Oeschger oscillations. Here, we observe a strong agreement between our paleo-precipitation reconstruction and climate proxy records which are indicative of the strength of the Atlantic meridional overturning circulation and northern hemispheric temperature changes. The coherence of speleothem δ18O values with sedimentary 231Pa/230Th also on sub-millennial timescales supports a persistent link of regional precipitation variability to ocean circulation variability. Spectral analysis further suggests that multi-decadal to centennial variability persisted in the western tropical Atlantic hydro-climate not only during stadial and interstadial conditions, but also during the last Glacial maximum, supporting the hypothesis that the Atlantic low-latitude regions respond to internal modes of climate variability on these time scales regardless of the global climate state.

The compilation of our dataset from Puerto Rico with other paleo-precipitation records allows for the reconstruction of past changes in position, strength and extent of the intertropical convergence zone in the western tropical Atlantic and reveal the existence of spatio-temporal gradients in response to millennial to orbital climate change.
Aeolus / ALADIN data analysis in Korea
Authors: Shin Hyemin , Ahn Myoung-Hwan , Kim Jisoo , Chung Chu-Yong
Published: March 2020

The assimilation of the Atmospheric Laser Doppler Instrument (ALADIN) wind profile data is expected to play a significant role in improving the skills of numerical weather prediction model. In this study, we analyze the Aeolus/ALADIN data over Korea region using data obtained by radiosonde, dropsonde and the ground based windprofiler. In addition, we analyze data by comparing with atmospheric movement vector (AMV) derived from the Geostationary Korea Multi Purpose Satellite -2A (GK-2A). The ALADIN wind data within the 150 km from the radiosonde/dropsonde/windprofiler station and within ±60 minutes to their observation time are collocated. The AMV data having the closest altitude to the ALADIN altitude are compared, within the 150 km from the ALADIN observation. With the limited number of collocated data obtained from August 29th to September 1th, 2019, the comparison results show a rather large discrepancy. In case of the radiosonde, RMSD is estimated to be 2.50 m/s and 2.67 m/s in the Rayleigh channel and the Mie channel, respectively. In case of the AMV, the error statistics varies significantly with the quality index of AMV data. When the quality index of 0.8 is applied to the AMV data, RMSD for the infrared AMV is about 3.36 m/s. In the conference, comparison results of all instruments along with the extended time period are going to be presented.
Ignoring spatial dependence misestimates flood risk at the European scale
Authors: Nguyen Viet Dung , Metin Ayse Duha , Alfieri Lorenzo , Vorogushyn Sergiy , Merz Bruno
Published: March 2020

Flooding is a major problem worldwide causing many fatalities and economic losses. The quantification of flood risk can be difficult for large spatial scales due to its spatial variability. The traditional risk assessment approaches assuming unrealistic spatial homogeneity of flood return period for the entire catchment are often used and hence in many cases lead to misleading results especially for large-scale applications. In this study, we aim at investigating the influences of spatial dependence in flood risk estimation over national and continental scales by comparing the assessments under three spatial dependence assumptions: modelled dependence (MD), complete dependence (CD) and complete independence (CI) of flow return periods. In order to achieve the aim, we develop a copula-based model representing the dependence structure of annual maximum stream flow (AMS) at 507 stations (with basin area > 500km2) across Europe and use it to generate long-term (10000 years) spatially coherent AMS at these locations. The generated series at multiple sites are then used for estimating associated flood loss considering two levels (with and without) of flood protection. The flood risk is estimated and aggregated for the representative 3 regions (England, Germany and Europe) and for the three dependence assumptions considering also the role of tail dependence of the used copulas. The results highlight that ignoring spatial dependence misestimates flood risk. The deviation from the modelled risk (under-/over-estimation) depends differently on the assumptions of spatial dependence, tail dependence, flood protection level and spatial scales. For example, under CD assumption for 200-year return period and considering flood protection, approximately 2.5-, 3- and 3.5-fold overestimation of flood risk in England, Germany and Europe, respectively, is found.
Climate driven mobility of the early humans in SW Asia: Preliminary evidence from Iranian Stalagmites
Authors: Sharifi Arash , Pourmand Ali , Sevag Mehterian , Swart Peter , Peterson Larry , A. K. Lahijani Hamid
Published: March 2020

The dynamic interaction between synoptic systems across the Iranian Plateau in West Asia has made this region highly sensitive to climate change.   Early human migration routes in the region from Africa to Eurasia are marked by Paleolithic sites and provide a unique opportunity to study the impact of climate variability on early human mobility and settlement. Preliminary results are based on δ18O and elemental time series from three stalagmites in central-northwest Iran with robust U-Th chronology over the last 450,00 years The data raise the possibility that the Iranian Plateau experienced several episodes of wet conditions during the Paleolithic period. This is in line with findings from a compilation of independent proxy records of lake sediment in northwest Iran and loess deposits in northeast Iran. The fluctuation of Mn abundance and δ18O values in these stalagmites correlate with the Greenland ice core record (NGRIP) and coincide with periods of high solar intensity in the northern hemisphere. These early results indicate wet conditions may have prevailed over the Iranian Plateau during marine isotope stages MIS5a,b, MIS5c, MIS5e, MIS6b, MIS6d-e and most likely also during stages MIS3-4 and MIS7a. Early human occupation of the Southern Caucasus, Zagros, and the Near East regions coincides with the upper Pleistocene wet periods. The co-variability between the proxy data from these speleothems and solar insolation at 30°N suggests that early human settlements/occupations may have been more prevalent along coastal regions of the Near East during dry climate episodes.
Vertically Driven Dynamics and Magmatism of Rapid Subduction Initiation in the Western Pacific
Authors: Maunder Ben , Goes Saskia , Prytulak Julie , Reagan Mark
Published: March 2020

Plate tectonics requires the formation of plate boundaries. Particularly important is the enigmatic initiation of subduction: the sliding of one plate below the other, and the primary driver of plate tectonics. A continuous, in situ record of subduction initiation was recovered by the International Ocean Discovery Program Expedition 352, which drilled a segment of the fore-arc of the Izu-Bonin-Mariana subduction system, revealing a distinct magmatic progression with a rapid timescale (approximately 1 million years). Here, using numerical models, we demonstrate that these observations cannot be produced by previously proposed horizontal external forcing. Instead a geodynamic evolution that is dominated by internal, vertical forces produces both the temporal and spatial distribution of magmatic products, and progresses to self-sustained subduction. Such a primarily internally driven initiation event is necessarily whole-plate scale and the rock sequence generated (also found along the Tethyan margin) may be considered as a smoking gun for this type of event.
Global climate model evaluation and selection using the interactive tool GCMeval
Authors: Parding Kajsa , Landgren Oskar A. , Dobler Andreas , McSweeney Carol F. , Benestad Rasmus E. , Erlandsen Helene B. , Mezghani Abdelkader , Gregow Hilppa , Räty Olle , Viktor Elisabeth , El Zohbi Juliane , Bøssing Christensen Ole , Loukos Harilaos
Published: March 2020

We present the interactive web application GCMeval, available at https://gcmeval.met.no. The tool is a useful resource for climate services by illustrating how model selection affects representation of future climate change. GCMeval was developed in a co-design process engaging users. Based on a thorough analysis of user demands, needs and capabilities, two different user groups were defined: Data users with lots of experience with data processing and Product users with a strong focus on information products. The available data, information, and user interface in GCMeval are tailored to the requirements of the data users.

In the tool, the user can select all or a subset of models from the CMIP5 and CMIP6 ensembles and assign weights to different regions, seasons, climate variables, and skill scores. The tool provides visualizations of the spread of future changes in temperature and precipitation which allows the user to study how the sub-ensemble fits in relation to the full multi-model ensemble and to compare climate model results for different regions of the world. A ranking of individual model performance for recent past climate is also provided. The tool can be used to aid in model selection for climate or impact studies, or to illustrate how an already existing selection represents the range of possible future climate outcomes.
Invigoration of Indian Ocean zonal circulation drove Pleistocene eastern African aridification
Authors: van der Lubbe Jeroen , Hall Ian , Barker Steven , Hemming Sidney , Just Janna , Baars Tim , Joordens Josephine , Starr Aidan , 361 Scientists Expedition
Published: March 2020

The coupled ocean-atmosphere circulation of the Indian Ocean Dipole (IOD) controls monsoon rainfall in eastern Africa and southeast Asia at seasonal to decadal time-scale. In years when the dipole is particularly active, it can lead to catastrophic floods and droughts. A growing body of evidence suggests that IOD variability influenced the continental hydroclimate also at longer timescales in the past and thus may have affected human evolution.  However, long-term continuous high-resolution well-dated records have so far been unavailable to test this hypothesis. In 2016, long-term continuous deep-sea sediment cores have been recovered from the Davie Ridge in the Mozambique Channel during Expedition 361 ‘Southern African Climates’ as part of the International Ocean Discovery Program (IODP).

Here, we present a more than seven million-year-long multi-proxy record of Mozambique Channel Throughflow (MCT), which is tightly coupled to IOD variability; defined here as the zonal sea surface temperature gradient (ΔSST) between the Indo-Pacific warm pool (IPWP) and the Arabian Sea. We show that the MCT was relatively weak and steady until 2.1 million years ago (Ma), when it started to significantly accelerate with progressively increasing glacial-interglacial amplitude, culminating in high flow speeds from 0.8 Ma onwards. The invigoration of MCT activity coincided with increasing zonal ΔSST, which fuels the atmospheric Walker Cell circulation along the tropical Indian Ocean.  Our results demonstrate that the overall intensification of the Indian Ocean Walker Cell amplified the coupled ocean-atmosphere Indian Ocean zonal circulation at orbital time-scales, which agrees with the heightened glacial continental aridity recorded in other eastern African climate proxy records. We argue that the corresponding progressively drier glacials alternated with relative humid interglacials, providing the climatic-environmental setting –varying at seasonal to orbital timescales- for speciation and global expansion of our genus Homo after 2.1 Ma.
Detecting change in Landsat time series with BFAST in the eastern Hindu Kush region
Authors: Khan Saeed Akhtar , Sass Oliver , Samimi Cyrus
Published: March 2020

Environmental change is a trigger of land use change and possibly for migration in the eastern Hindu Kush mountains. Vegetation along the river valleys has undergone alterations by the impact of geomorphological processes and flood dynamics, but little research has been carried out to detect and map these changes. This study aims to close research gaps by detecting change within Landsat time series for the eastern Hindu Kush region.

The study area is approximately 25000 km² large and located in the highlands of northern Pakistan and eastern Afghanistan. It is part of upper Indus basin and is prone to natural hazards such as floods, glacial lake outbursts and landslides.

The opening of the United States Geological Survey (USGS) Landsat data archive in 2008 led to the development of several satellite image-based time series methods for change detection. Among them, Breaks For Additive Seasonal and Trend (BFAST) was developed in 2010 to detect changes in both trend and seasonal components of the time series. The BFAST tool iteratively decomposes the time series into trend, seasonal and remainder components. The changes in the trend component denote abrupt and gradual changes while changes in seasonal component represent phenological changes.  

In this study we use Landsat data in time series analysis to detect change by using BFAST. All available Surface reflectance derived data is accessed from the Landsat data archive of USGS (World Reference System-2, Path 151 and Row 35) for the years 1988 to 2019. Data is acquired from the corresponding scenes of Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI). It is processed to Landsat Level-2 Surface Reflectance Product by USGS and therefore has already undergone geo-referencing, atmospheric correction and detection of clouds and shadow. Data have spatial and temporal resolutions of 30 m and 16 days respectively.

The BFAST approach was first tested on locations with a known history of change (e.g. floods) and then scaled up to the whole study area. The magnitude and timing of the change was detected and mapped for the study area. We expect that the findings of the research will benefit future local and regional risk studies.
Implementing FAIR in a Collaborative Data Management Framework
Authors: Schäfer Angela , Anselm Norbert , Eilers Janik , Frickenhaus Stephan , Gerchow Peter , Glöckner Frank Oliver , Haas Antonie , Herrarte Isabel , Koppe Roland , Macario Ana , Schäfer-Neth Christian , Silva Brenner , Fischer Philipp
Published: March 2020

Today's fast digital growth made data the most essential tool for scientific progress in Earth Systems Science. Hence, we strive to assemble a modular research infrastructure comprising a collection of tools and services that allow researchers to turn big data into scientific outcomes.

Major roadblocks are (i) the increasing number and complexity of research platforms, devices, and sensors, (ii) the heterogeneous project-driven requirements towards, e. g., satellite data, sensor monitoring, quality assessment and control, processing, analysis and visualization, and (iii) the demand for near real time analyses.

These requirements have led us to build a generic and cost-effective framework O2A (Observation to Archive) to enable, control, and access the flow of sensor observations to archives and repositories.

By establishing O2A within major cooperative projects like MOSES and Digital Earth in the research field Earth and Environment of the German Helmholtz Association, we extend research data management services, computing powers, and skills to connect with the evolving software and storage services for data science. This fully supports the typical scientific workflow from its very beginning to its very end, that is, from data acquisition to final data publication. 

The key modules of O2A's digital research infrastructure established by AWI to enable Digital Earth Science are implementing the FAIR principles:

Sensor Web, to register sensor applications and capture controlled meta data before and alongside any measurement in the field

Data ingest, allowing researchers to feed data into storage systems and processing pipelines in a prepared and documented way, at best in controlled NRT data streams

Dashboards, allowing researchers to find and access data and share and collaborate among partners

Workspace, enabling researchers to access and use data with research software in a cloud-based virtualized infrastructure that allows researchers to analyse massive amounts of data on the spot

Archiving and publishing data via repositories and Digital Object Identifiers (DOI).
Carto PMAi : a measurement campaign to evaluate the exposition of the workers and the general population to the EMP of interest
Authors: Leocat Erell , Deneuvillers Christine , Richard Patrick
Published: March 2020

The French Ministry of Health, Ministry of Labor and Ministry of Environment are faced with the emerging issue of cleavage fragment particles with same chemical composition as actinolite asbestos in aggregates used in road pavement. In 2015, the National Agency for Food, Environmental and Occupational Health and Safety (ANSES) published a literature review on the health effect of these non asbestiform particles. The conclusion is that any study can show the evidence of risk absence related to these particles.

After this first report, the French government mandated the national agency to conduct a research on the emission source of EMPs of interest (EMPi; ANSES, 2017). These particles correspond to the asbestiform and non-asbestiform varieties of the six regulated asbestos minerals and to four other mineral fibers. The agency recommends following the precaution principle by applicating the asbestos regulation to these whole particles. It also recommends leading a measurement campaign for exploring the potential exposure of workers and general population to EMPi during some construction activities.

In this context, the three ministries asked in 2017 the Professional Organization for Risk Prevention in Building and Public Work Sector (OPPBTP) to coordinate a project on EMPi, based on the requirements of the ANSES second report. This national project, called Carto PMAi, addresses the potential exposure of populations to EMPi, in order to provide reliable data to the three ministries to set up legal provisions. The first step is to build reliable protocols to measure EMPi in materials and in the air. Several national scientific organisms and asbestos testing laboratories take part at this phase that includes interlaboratory comparisons. The second phase is the measurement campaign in construction areas, including quarries and earthwork in natural environment.
Big Data for flood management: Realising the benefits for developing countries
Authors: Bhattacharya Mis Namrata
Published: March 2020

Agenda 2030 goal 11 commits towards making disaster risk reduction an integral part of sustainable social and economic development. Flooding poses some of the most serious challenges in front of developing nations by hitting hardest to the most vulnerable. Focussing on the urban poor, frequently at highest risk are characterised by inadequate housing, lack of services and infrastructure with high population growth and spatial expansion in dense, lower quality urban structures. Use of big data from within these low-quality urban settlement areas can be a useful step forward in generating information to have a better understanding of their vulnerabilities. Big data for resilience is a recent field of research which offers tremendous potential for increasing disaster resilience especially in the context of social resilience. This research focusses to unleash the unrealised opportunities of big data through the differential social and economic frames that can contribute towards better-targeted information generation in disaster management. The scoping study aims to contribute to the understanding of the potential of big data in developing particularly in low-income countries to empower the vulnerable population against natural hazards such as floods. Recognising the potential of providing real-time and long-term information for emergency management in flood-affected large urban settlements this research concentrates on flood hazard and use of remotely sensed data (NASA, TRMM, LANDSAT) as the big data source for quick disaster response (and recovery) in targeted areas. The research question for the scoping study is: Can big data source provide real-time and long- term information to improve emergency disaster management in urban settlements against floods in developing countries?  Previous research has identified several potentials that big data has on faster response to the affected population but few attempts have been made to integrate the factors to develop an aggregated conceptual output . An international review of multi-discipline research, grey literature, grass-root projects, and emerging online social discourse will appraise the concepts and scope of big data to highlight the four objectives of the research and answer the specific questions around existing and future potentials of big data, operationalising and capacity building by agencies, risk associated and prospects of maximising impact. The research proposes a concept design for undertaking a thematic review of existing secondary data sources which will  be used to provide a holistic picture of how big data can support in resilience through technological change within the specific scope of social and environmental contexts of developing countries. The implications of the study lie in the system integration and understanding of the socio-economics, political, legal and ethical contexts essential for investment decision making for strategic impact and resilience-building in developing nations.
Damage simulator - a tool to explore the effects of flood risk drivers on the development of flood damage in Switzerland
Authors: Brughelli Mattia , Fehlmann Anna , Mertin Mirjam , Zischg Andreas , Mosimann Markus , Martius Olivia , Keiler Margreth
Published: March 2020

Flood risk assessment and the design of risk reduction strategies often neglect the influence of socio-economic development on future exposure and vulnerability to floods and their development over time. Flood risks will increase or decrease depending on proactive adaptations of both households and government. A cooperation between household and government is therefore essential and may be reached by encouraging a constructive flood risk dialog. To overcome communication barriers, ease knowledge transfer between stakeholders and allow an integral rise in flood risk awareness the web-based tool “Flood damage simulator” is introduced.

As a communication and awareness-raising instrument for flood risk management, the tool is directed at various user groups such as policy makers, local authorities, spatial planners as well as researchers. The tool offers scenarios which represent the magnitude of flood damages to be expected today and show possible trends in the near future. Furthermore, it is possible to customize a user defined scenario in which the key flood risk drivers exposure, vulnerability and flood extension can be individually adapted, thus breaking down a complex topic in more comprehensible subunits. Generated knowledge and awareness might promote proactive adaptation of both households and government leading to a reduction of flood risk.
Multidimensional context for extreme analysis of daily streamflow, rainfall and accumulated rainfall across USA
Authors: Nezi Maria , Tsoukalas Ioannis , Ntigkakis Charalampos , Efstratiadis Andreas
Published: March 2020

Statistical analysis of rainfall and runoff extremes plays a crucial role in hydrological design and flood risk management. Usually this analysis is performed separately for the two processes of interest, thus ignoring their dependencies, which appear at multiple temporal scales. Actually, the generation of a flood strongly depends on soil moisture conditions, which in turn depends on past rainfall. Using daily rainfall and runoff data from about 400 catchments in USA, retrieved from the MOPEX repository, we investigate the statistical behavior of the corresponding annual rainfall and streamflow maxima, also accounting for the influence of antecedent soil moisture conditions. The latter are quantified by means of accumulated daily rainfall at various aggregation scales (i.e., from 5 up to 30 days) before each extreme rainfall and streamflow event. Analysis of maxima is employed by fitting the Generalized Extreme Value (GEV) distribution, using the L-moments method for extracting the associated parameters (shape, scale, location). Significant attention is paid for ensuring statistically consistent estimations of the shape parameter, which is empirically adjusted in order to minimize the influence of sample uncertainty. Finally, we seek for the possible correlations among the derived parameter values and hydroclimatic characteristics of the studied basins, and also depict their spatial distribution across USA.
The contribution of numerical models to our understanding of the Phanerozoic CO2 history
Authors: Godderis Yves , Donnadieu Yannick
Published: March 2020

Our understanding of the geological regulation of the carbon cycle has been deeply influenced by the contribution of Bob Berner with his well-known model GEOCARB. Here, we will present a fundamentally different carbon cycle model that explicitly accounts for the effect of the paleogeography using physically based climate simulations and using 22 continental configurations spanning the whole Phanerozoic (GEOCLIM, geoclimmodel.wordpress.com). We will show that several key features of the Phanerozoic climate can be simply explained by the modulation of the carbon cycle by continental drift with the notable exception of the Late Paleozoic Ice Age, which is explained by the intense weathering of the Hercynian mountain range. In particular, the continental drift may have strongly impacted the runoff intensity as well as the weathering flux during the transition from the hot Early Cambrian world to the colder Ordovician world. Another fascinating example is the large atmospheric CO2 decrease simulated during the Triassic owing to the northward drift of Pangea exposing large continental area to humid sub-tropics and boosting continental weathering. Conversely, our model fails to reproduce the climatic trend of the last 100 Ma. This is due to the highly dispersed continental configurations of the last 100 Ma that optimize the consumption of CO2 through continental weathering. This discrepancy may be reduced if we account for a larger influence of the Earth degassing flux on the atmospheric CO2 evolution, which could come from the increase contribution of the pelagic component on the oceanic crust on the global carbonate flux and from the many sub-marine LIPs occurring during the Late Cretaceous.

 
Optimizing large-eddy simulations for investigating the energy-balance closure problem at typical flux measurement heights
Authors: Wanner Luise , De Roo Frederik , Mauder Matthias
Published: March 2020

The eddy-covariance method generally underestimates sensible and latent heat fluxes, resulting in an energy-balance gap from 10 % to even 30 % across sites worldwide. In contrast to single-tower eddy-covariance measurements, large-eddy simulations (LES) provide information on a 3D array of grid points and can capture atmospheric processes such as secondary circulations on all relevant scales, which makes them a powerful tool to investigate this problem. In order to compare LES results to field measurements at 20 m height from the CHEESEHEAD (Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors) campaign, a LES-setup that provides comparability to the measurements at these low levels is necessary. However, former LES studies have shown that the energy balance is almost closed near the surface, which does not reflect the energy-balance gap in measurements. One possible reason might be the common use of prescribed surface fluxes that cannot adapt to changes in surface temperature and moisture, which would allow for the self-reinforcement of secondary circulations. Therefore, we set up an idealized study, in which we compare the performance of the land-surface and plant-canopy models implemented in PALM to the use of prescribed surface fluxes above homogeneous forest and grassland ecosystems under different atmospheric conditions with respect to realistic energy-balance closure behavior. Furthermore, we evaluate the performance of a dynamic subgrid-scale model, as well as an alternative to the Monin-Obukhov similarity theory (Banerjee et al. 2015, Q. J. R. Met. Soc.).