bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of the megacity’s growth over the hydrological cycle of the Bogotá basin (Colombia) using distributed model
Authors: Romero Claudia P , Frances Felix
Published: March 2020

According to United Nations, the world population in 2050 will reach 9.7 billion and it is expected that 68% will live in urban centers. An important part of the urban population in Latin America is concentrated in megacities such as Mexico City and Sao Paulo, which currently have more than 20 million inhabitants. Buenos Aires, Rio de Janeiro, Lima and Bogotá are now megacities under development. This accelerated process of urbanization entails effects on the demand of the natural resources and the impulse of the environmental negative effects related to the contamination of soil, air and water.

The megacity of Bogotá and its metropolitan area includes more than 10 million inhabitants being the higher population density of Colombia. Being the country’s capital city, it is the core of its economic development and it is currently one of the main business centers of South America.

From an environmental perspective Bogotá basin becomes a territory with high water vulnerability. The accelerated population increase (it has doubled during the last four decades), has caused, among others, high water resources demand. The industrial concentration in this territory has also affected both surface and subsurface water quality, causing an increase in the purification costs.

The objective of this study is to analyze the influence in the water cycle of the urban growth of the city of Bogotá in the last forty years. In this period the Bogotá river basin was modeled for the years 1985, 2005 and 2014, using the TETIS distributed hydrological simulation model. Results allow to identify the alterations in the basin water balance induced by changes in land use during the period of analysis.Por favor inserte su resumen HTML aquí.
The significance of wave–current interaction on modelled wave fields in the Baltic Sea
Authors: Kanarik Hedi , Tuomi Laura , Björkqvist Jan-Victor , Kärnä Tuomas , Westerlund Antti
Published: March 2020

Currents in the Baltic Sea are relatively weak and are thus often expected to have a negligible effect on sea surface waves. To evaluate the magnitude of wave–current interactions in the Baltic Sea, we ran the third generation wave model WAM with and without surface currents from the 3D hydrodynamical model Nemo4. The results showed that the currents have a notable effect on wave field only on rare occasions and that the effects are largest in coastal areas of the Baltic Proper, most notably in the western Gotland Basin, and the Gulf of Finland. The simulations showed that the currents in the Baltic Sea can cause differences of significant wave height up to tens of centimeters. More notable effect was the change in the peak of the wave spectrum from swell to wind driven waves and vice versa in some occasions. In our study we mostly focus on the events of strong wave–current interactions in the northern Baltic Proper and Gulf of Finland as we have measured wave spectra available from these locations. From the comparison with wave buoy measurements we see that implementing surface currents slightly improves the modelled peak period in the Gulf of Finland. The Gulf of Finland is of special interest also because a group of ADCP’s were installed close to the wave buoy. The current measurements from these devices can therefore be used to evaluate the accuracy of the currents in the hydrodynamical model.
Solar radio burst interference index dedicated to GNSS single and double frequency users
Authors: Chevalier Jean-Marie , Bergeot Nicolas , Defraigne Pascale , Marque Christophe , Pinat Elisa
Published: March 2020

Intense solar radio bursts (SRBs) emitted at L-band frequencies are a source of radio frequency interference for Global Navigation Satellite Systems (GNSS) by inducing a noise increase in GNSS measurements, and hence degrading the carrier-to-noise density (C/N0). Such space weather events are critical for GNSS-based applications requiring real-time high-precision positioning.

Since 2015, the Royal Observatory of Belgium (ROB) monitors in near real-time the C/N0 observations from the European Permanent Network (EPN). The monitoring allows to detect accurately the general fades of C/N0 due to SRBs over Europe as from 1 dB-Hz. It provides in near real-time a quantification of the GNSS signal reception fade for the L1 C/A and L2 P(Y) signals and notifies civilian single and double frequency users with a 4-level index corresponding to the potential impact on their applications. This service is part of the real-time monitoring service of the PECASUS project of the International Civil Aviation Organization (ICAO) which started end of 2019.

Results of this 5-year monitoring will be discussed, including the 3 SRBs of 2015 and 2017, together with the new developments toward a global index using the International GNSS Service (IGS) network. In addition, we will show how the SRB monitoring is sometimes interfered by GPS flex power campaigns on the satellites from blocks IIR-M and IIF, and how it is mitigated . The routine and transient GPS flex power campaigns will be presented in terms of C/N0 variations for the EPN and IGS networks.
Sediment failure of St. Pierre Slope: new insights of failure mechanisms and slope instability due to the 1929 Grand Banks Earthquake
Authors: Schulten Irena , Mosher David , Piper David , Krastel Sebastian , MacKillop Kevin
Published: March 2020

The 1929 Grand Banks submarine landslide was triggered by a Mw 7.2 strike slip earthquake on the southwestern Grand Banks of Newfoundland. Studies following the event by several decades were the first to recognize that slope failure can cause tsunamis. These studies identified St. Pierre Slope as the main failure area and showed widespread, shallow (<25 m-thick), translational and possibly retrogressive sediment failures occurred predominately in >1700 m water depth (mwd). It seems unlikely this style of failure in deep water generated a tsunami that had >13 m of run-up along the coast of Newfoundland. The objective of this study is to identify possible alternative tsunami source mechanisms and pre-conditioning factors that may have led to sediment instability. These objectives are addressed using a comprehensive data set of multiscale 2D seismic reflection, multibeam swath bathymetry and laboratory geomechanical test data. Results show numerous reflection offsets within the Quaternary section of the slope underneath modern seafloor escarpments (750-2300 mwd).  These offsets appear down to 550 m below seafloor (mbsf) and are interpreted as low angle (~17°), planar-normal faults of <100 m-high vertical and ~330 m of horizontal displacement. The faults are interpreted as part of a massive (~560 km³) complex slump with evidence for multiple décollements (250 mbsf & 400-550 mbsf) and slumping in at least two directions. Infinite slope stability analysis using peak ground acceleration (PGA) indicates that a combination of earthquake loading and the presence of geomechanical weak layers are needed to explain the slope failure. At St. Pierre Slope, the analysis of sediment cores shows that geomechanical weak layers form as a consequence of underconsolidation in connection with excess pore pressures that are related to: 1) high sedimentation rates, 2) instantaneous deposition of mass transport deposits (MTD’s) and sandy turbidites, and 3) the presence of gas. The décollements of the slump are associated with MTD’s and sediment waves that likely form weak layers. The layers of sediment waves are assumed to consist of sorted silts or fine sands and are therefore likely to be susceptible to excess pore pressure development during earthquake loading. Excess pore pressure development results in reduced effective stress and higher potential for instability. It is interpreted, therefore, that the 1929 earthquake triggered displacement of a 550 m-thick slump with ~100 m of vertical seafloor displacement. This instantaneous displacement of the slump in 750 mwd with a seafloor volume displacement of 70 to 130 km² is likely a more effective source for tsunami generation than the translational, shallow (<25 m) failures in deeper water.
Inoculation of bacteria for the amelioration of sandy soil under drought
Authors: Angulo Fernández Violeta Carmen , Hefting Mariet , Kowalchuk George
Published: March 2020

Soil degradation represents a pressing worldwide problem that is being accelerated by processes of erosion, depletion of soil organic matter, soil compaction, acidification, salinization, and drought. Soil microorganisms can influence soil aggregation via a range of mechanisms such as the production of exopolysaccharides and other extracellular matrix polymers such those involved in biofilm formation. In this study, we south to use bacteria harboring specific traits to enhance soil aggregation. To this end, 120 bacterial strains were isolated from an experiment field under drought conditions and tested for their ability to grow under drought, salinity tolerance, rapid growth, biofilm, and exopolysacharides production. Based upon this trait assessment, 24 strains were further tested at two moisture levels for their ability to impact soil structure after 8 weeks of incubation at 25ºC. The mean weight diameter (MWD) of water-stable aggregates and carbohydrates were determined for treated soils. Three strains were shown to impact soil aggregate properties at the higher moisture content: one affiliated with Bacillus niacini, one affiliated with Paenarthrobacter nitroguajacolicus and one of unclear classification. The first of these strains also affected soil structure at the lower moisture level. This B. niacini strain also increased the carbohydrate content of the soil, as did two other strains, related to B. wiedmannii and B. aryabhattai, respectively. However, no positive correlation was observed between the MWD and the production of carbohydrates in soil. Our results suggest that soil inoculation with specific microbial strains can improve soil structure.
Girls into Geoscience - Ireland
Authors: Wallace Elspeth , McAuliffe Fergus , Blowick Aoife , McNamara Maria , Morris Emma , Owen Amanda , Boulton Sarah , Fisher Jodie
Published: March 2020

The geosciences are an undeniably male-dominated sector (80/20 male/female in 2008). This has led to a loss of female talent and lack of diversity within the sector. Retention of female students in the geosciences is highest where students can identify with same gender career/industry leaders (Hernandez et al., Geosphere, Vol. 14,6, 2018), yet with few obvious female role models, poor female student retention has become a self-perpetuating problem. Girls into Geoscience was instigated in Plymouth in 2014 to interrupt this cycle. Girls around the ages of 16-17 and with any level of geoscience knowledge were invited to Plymouth to be introduced to the subject by leading females in the geoscience field. The annual event has proven so successful that it has now been taken up in Ireland.

Girls into Geoscience – Ireland (GiGie) is now at the end of its second year, having run three successful events across Ireland. GiGie has taken the form of day-long events which incorporate workshops, talks, networking and field-trip style elements. These events have been hosted in academic institutions and rotate annually to reach multiple areas of Ireland which often have limited access to STEM activities. So far, events have been hosted in Cork, Galway and Dublin. 100% of participants at the Cork event fed back that they were more likely to study geoscience, and similarly 83% of participants in Galway were now more likely to consider studying geosciences. 100% of Galway participants also had an increased understanding of geoscience careers, which is important considering the negative perceptions that are commonly attributed to careers in the geosciences. Suggestions from the events in Cork and Galway led us to incorporate a field-trip style element to the day, which was run for the first time in Dublin. The future of GiGie is bright. A planned expansion of the programme could lead to its most successful year yet. Across in the UK, expansion is also in action with further events taking place in Scotland, and a junior event being developed in Leicester. Gender balance is far from equal yet, but change is happening. We look forward to seeing Girls into Geoscience flourish.

“I loved (that) it was for girls. (It) made me feel more confident and that its possible to do science as a girl” – Participant, Cork.
Water as a critical zone currency: linking water storage and age to root uptake and biogeochemical transport
Authors: Kuppel Sylvain , Braud Isabelle , Goddéris Yves , Muddu Sekhar , Riotte Jean , Ruiz Laurent
Published: March 2020

Efforts to grasp hydrological functioning in landscapes have gradually been evolving from inferring when water output fluxes respond to precipitation and energy inputs in catchments, towards tracking down which water is present in the different flow pathways of the critical zone (CZ). In the CZ where almost all terrestrial life developed, quantifying water storage and age (residence times in stores and transit times in fluxes) is key to the understanding of how water is i) available to supply root uptake, ii) in interaction with regolith minerals and biota, and iii) a medium for solute transport. We propose an approach to characterize the dynamics and non-linearities of CZ functioning first by mapping time-varying transit times of water exiting as plant transpiration as well as soil evaporation and stream discharge, against the corresponding water storage states. This picture is then extended by assessing the resulting relationships between hydrological states and patterns of nutrient concentration in, and export out of, the critical zone. This analysis considers several spatial scales, from the hillslope to the whole catchment. To this end, we use simulations from a cascade of spatially-distributed numerical tools: a process-based ecohydrological model – accounting for the coupling between energy balance, critical zone hydrology and vegetation dynamics, and a modular chemical weathering model – simulating dissolution/precipitation rates of mineral phases based on kinetics laws. We particularly focus on the long-term experimental tropical catchment of Mule Hole in Peninsular India (part of both the Indian Kabini CZ observatory and the French CZ observatory network OZCAR), with a highly seasonal hydroclimate and deep unsaturated profile, and where extensive hydrometric and chemical datasets are available for model calibration and evaluation. We discuss the interplay between distinctively mobilized critical zone compartments for each output flux, and the time-varying spatial organization of flow pathways.
The extreme Greenland melt season of 2019 in a 16-year time series of surface energy balance at the Kangerlussuaq transect
Authors: Kuipers Munneke Peter , Reijmer Carleen , Smeets Paul , van den Broeke Michiel
Published: March 2020

In 2019, the Kangerlussuaq transect has experienced a record surface melt season at some stations, exceeding even the melt seasons of 2010 and 2012. We demonstrate that net radiation has been driving the high surface melt rates especially in the higher parts of the transect.

Since 2003, continuous measurements of the surface energy budget are made in a transect of four automatic weather stations, spanning the ablation area close to the ice edge to the accumulation are of the Greenland Ice Sheet. All available data have been homogenized and corrected, and an unprecedented time series of surface energy budget is presented here, including meltwater production. In this contribution, the melt season of 2019 is put into the longer-term context, and precise atmospheric drivers of the melt are exposed.

Sixteen years of data clearly reveal the inland and upward expansion of the ablation area. The weather station closest to the equilibrium line (S9) shows a clear and distinct reduction in albedo, and a relatively strong increase in surface melt, which has started to exceed accumulation during the period of observation. Photographs of the area around S9 show that the surface has undergone major changes between 2003 and 2019, now featuring many surface hydrological features that were completely absent in 2003.

These changes have important implications for the hydrology of the surface, the near-surface, and the underlying firn. A firn model calculation reveals that the entire firn column has been heating by several degrees Celsius in the percolation zone, due to refreezing of meltwater. Sudden, stepwise warming is seen in extreme melt seasons like 2019.
Wave-resonance fingerprint in the 2010 summer: a modelling experiment
Authors: Di Capua Giorgia , Kornhuber Kai , Rousi Eftychia , Sparrow Sarah , Wallom David , Coumou Dim
Published: March 2020

Summer 2010 was characterized by two contemporaneous extreme events: the Russian heat wave and the Pakistan flood. Several studies have shown a link between the two events, and Quasi-Resonant Amplification (QRA) has been suggested as an atmosphere-dynamic mechanism leading to the anomalous wavy circulation pattern which connected both extremes. Here, we aim at reproducing the 2010 circulation conditions in the Northern Hemisphere by obtaining a large ensemble of simulations from the Weather@home project within climateprediction.net (CPDN). We identify those ensemble members exhibiting a specific latitudinal temperature profile characterised by amplified high-latitude land warming (QRA - fingerprint) and investigate their surface temperature and upper level circulation properties. We show that when the QRA - fingerprint is present, the mid-latitude circulation bears similar characteristics to those observed in the 2010 summer: hot temperatures over European Russia and a wavy pattern in the upper-tropospheric meridional winds. As temperature profiles are projected to become increasingly similar to the QRA-fingerprint under future emission scenarios, these results provide further evidence that high latitude warming might favour persistent surface weather in the mid-latitudes.
Modelling study on the formation of pockets of open cells in marine stratocumulus cloud during CLARIFY
Authors: Simpson Emma , Choularton Tom
Published: March 2020

Due to the wide spread nature of marine stratocumulus cloud they have a significant impact on the Earth’s radiation budget. Such clouds are sensitive to the presence of aerosol, which can promote the break-up of a cloud deck into pockets of open cell convection (POC). The transition from a cloud deck to pockets of open cells changes the overall cloud albedo thus affecting the Earth’s radiation budget. The representation of stratocumulus cloud and the transition to POCs is poorly represented in current climate and weather models. This study aims to improve understanding of this process using extensive in-situ measurements made during the CLARIFY campaign of stratocumulus cloud decks, transition areas between overcast and open cell cloud structures as well as areas of POCs, to inform and compare to large-eddy simulations.

A variety of different aerosol situations occurred during CLARIFY, combinations of polluted/clean boundary layer and polluted/clean conditions above the cloud layer. Large-eddy simulations are conducted to investigate the sensitivity of clouds to changes in the observed aerosol conditions with a particular focus on whether or not the change in aerosol initiates cloud breakup.

The MetOffice NERC Cloud model (MONC) is used to preform the large-eddy simulations and employs the CASIM cloud microphysics scheme which includes activation of aerosol particles to cloud drops. Such a model set-up allows direct interaction between aerosols and clouds. Observations from CLARIFY are used to initialise and evaluate model simulations.
Detection of methane enhancements over the Eastern United States with improved TROPOMI retrievals
Authors: Lorente Alba , Borsdorff Tobias , aan de Brugh Joost , Butz Andre , Kumar Sha Mahesh , Langerock Bavo , F. Lunt Mark , Dammers Enrico , Hasekamp Otto , Landgraf Jochen
Published: March 2020

The TROPOspheric Monitoring Instrument (TROPOMI) aboard of the Sentinel 5 Precursor (S5P) has provided methane measurements for more than two years. The high accuracy together with the exceptional spatial resolution (7 x 7 km2, 7 x 5.2 km2 since August 2019) and temporal coverage (daily) of TROPOMI provides a unique perspective on local to regional methane enhancements. In this contribution, we discuss observations of enhanced methane concentrations over the United States. We analyse in detail temporal and spatial variability of methane over wetlands and agricultural areas along the Mississippi river and in Florida. To understand the observed CH4 anomalies regarding both natural and anthropogenic sources and transport at regional scales, we support our analysis with simulations from the GEOS-Chem atmospheric chemistry and transport model. We also investigate the possibility to use other datasets as a proxy for CH4 emissions (e.g. NO2 for agricultural areas, land surface temperature for wetlands). These results are based on an improved TROPOMI methane product that features among others a new bias correction that is fully independent of any reference measurements. The verification of the TROPOMI XCH4 data with ground-based measurements by the TCCON network yields a station-to-station variability of the XCH4 error below 10 ppb, in agreement with the comparison with the proxy methane product from the Japanese GOSAT and GOSAT-2 missions. The improved TROPOMI methane product is planned as a future update of the operational TROPOMI processor.

 

 
The National Data Centre Preparedness Exercise NPE 2019 - Scenario design and expert technical analyses
Authors: Ross J. Ole , Gestermann Nicolai , Gaebler Peter , Ceranna Lars
Published: March 2020

For detection of non-compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT) the global International Monitoring System (IMS) is being built up and nearly complete. The IMS is designed to detect and identify nuclear explosions through their seismic, hydroacoustic, infrasound, and radionuclide signature. The IMS data are collected, processed to analysis products, and distributed to the signatory states by the International Data Centre (IDC) in Vienna. The member states themselves may operate National Data Centers (NDC) giving technical advice concerning CTBT verification to their government. NDC Preparedness Exercises (NPE) are regularly performed to practice the verification procedures for the detection of nuclear explosions in the framework of CTBT monitoring. The NPE 2019 scenario was developed in close cooperation between the Italian NDC-RN (ENEA) and the German NDC (BGR). The fictitious state RAETIA announced a reactor incident with release of unspecified radionuclides into the atmosphere. Simulated concentrations of particulate and noble gas isotopes at IMS stations were given to the participants. The task was to check the consistency with the announcement and to serach for waveform events in the potential source region of the radioisotopes. In a next step, the fictitious neighbour state EASTRIA provided further national (synthetic) measurements and requested assistance from IDC with so called Expert Technical Analysis (ETA) about the origin of those traces. The presentation shows aspects of scenario design, event selection, and forward amospheric transport modelling as well as radionuclide and seismological analyses.   
Painting Science in Helsinki
Authors: Buenrostro Mazon Stephany , Lauri Anniina , Duplissy Ella Maria , Lampilahti Janne , Makkonen Risto , Mielonen Tero , Pulkkinen Maija , Rantala Maikki , Riuttanen Laura , Ruuskanen Taina
Published: March 2020

We took science to the streets of Helsinki using urban art in order to foster communication between scientists and the general public.

Researchers from the Institute for Atmospheric and Earth System Research (INAR) and Finnish Meteorological Institute, together with artists from Helsinki Urban Art co-designed a public mural that joined climate research, art and literary characters of Alice in Wonderland. The Climate Wall illustrates the 1.5°C and 4°C pathways and highlights the need for a transition from a greenhouse-gas spewing caterpillar into a sustainable butterfly. The wall includes the hashtag #ScienceInHelsinki and INAR’s twitter handle inviting passers-by to ask scientists questions anytime.

The design of the mural was a joint effort, from posing the starting question, “what is the key message we want to deliver?”, to the final imagery used on the wall (and some actual painting!). Methods used for the co-design process included in-person workshops, a facebook group, and online virtual ‘whiteboards’, which resulted in a collateral result of this project: how scientists and artists can work together effectively.

The Climate Wall was inaugurated in a public event at Helsinki Central Library Oodi auditorium in December 2019 with a short presentation, a panel discussion with some of the scientists and artists, and a children’s workshop (“The Art of Asking Questions”).

The project took place from May 2019 until the mural’s completion on October 2019, and was funded by the Finnish Arts Promotion Center (Taike).
Characterizing sown biodiverse pastures using remote sensing data with machine learning
Authors: Morais Tiago G. , Vilar Pedro , Jongen Marjan , Rodrigues Nuno R. , Gama Ivo , Domingos Tiago , Teixeira Ricardo F.M.
Published: March 2020

In Portugal, beef cattle are commonly fed with a mixture of grazing and forages/concentrate feed. Sown biodiverse permanent pastures rich in legumes (SBP) were introduced to provide quality animal feed and offset concentrate consumption. SBP also sequester large amounts of carbon in soils. They use biodiversity to promote pasture productivity, supporting a more than doubling in sustainable stocking rate, with several potential environmental co-benefits besides carbon sequestration in soils.
Here, we develop and test the combination of remote sensing and machine learning approaches to predict the most relevant production parameters of plant and soil. For the plants, we included pasture yield, nitrogen and phosphorus content, and species composition (legumes, grasses and forbs). In the soil, we included soil organic matter content, as well as nitrogen and phosphorus content. For soils, hyperspectral data were obtained in the laboratory using previously collected soil samples (in near-infrared wavelengths). Remotely sensed multispectral data was acquired from the Sentinel-2 satellite. We also calculated several vegetation indexes. The machine learning algorithms used were artificial neural networks and random forests regressions. We used data collected in late winter/spring from 14 farms (more than 150 data samples) located in the Alentejo region, Portugal.
The models demonstrated a good prediction capacity with r-squared (r2) higher than in 0.70 for most of the variables and both spectral datasets. Estimation error decreases with proximity of the spectral data acquisition, i.e. error is lower using hyperspectral datasets than Sentinel-2 data. Further, results not shown systematic overestimation and/or underestimation. The fit is particularly accurate for yield and organic matter, higher than 0.80. Soil organic matter content has the lowest standard estimation error (3 g/kg soil – average SOM: 20 g/kg soil), while the legumes fraction has the highest estimation error (20% legumes fraction).
Results show that a move towards automated monitoring (combining proximal or remote sensing data and machine learning methods) can lead to expedited and low-cost methods for mapping and assessment of variables in sown biodiverse pastures.
First hints for the influence of planetary waves on extreme temperature events with a focus on Bavaria and the Alpine Region
Authors: Laux Dominik , Küchelbacher Lisa , Wüst Sabine , Bittner Michael
Published: March 2020

Planetary waves are global scale waves in the atmosphere, which mainly dominate the atmospheric circulation in mid latitudes. It is discussed whether planetary wave activity increases due to the decrease of the meridional temperature gradient between the equator and the pole. As a result, large-scale weather patterns in mid latitudes should change, leading to a change in the occurrence of extreme weather events.

In order to analyze whether the occurrence of extreme temperature events has already changed, an algorithm was developed that identifies extreme temperature events in ERA5 temperature data from 1979 to 2019 in different height levels (1000hPa – 1hPa). We analyze the occurrence frequency of extreme temperature events in mid latitudes of the Northern Hemisphere as well as in Bavaria and in the Alpine region. To relate changes in the occurrence of extreme temperature events to possible changes of the planetary wave activity, we use the so-called dynamic activity index (DAI), which is operationally derived from ERA reanalysis temperature data at DLR.

In the troposphere, our analyses show that the occurrence frequency of heat events increases whereas the opposite holds for cold events. This is consistent with the expected effect of increasing average temperatures on the occurrence frequency of extreme temperature events. In the stratosphere, however, we observe an increase of cold events and a constant number of heat events. We conclude that tropospheric and stratospheric driving factors for the occurrence of extreme temperature events differ. The stratospheric development can be explained by increasing planetary wave activity as it is deduced from the DAI.

This work received funding from the Bavarian State Ministry of the Environment and Consumer Protection.
Integrating tri-stereo Pleiades images with infrared satellite data to monitor volcanoes: the 2019 Stromboli eruption
Authors: Ganci Gaetana , Bilotta Giuseppe , Calvari Sonia , Cappello Annalisa , Corradino Claudia , Del Negro Ciro
Published: March 2020

The 3 July 2019 explosive paroxysm at Stromboli volcano (Italy) caused severe concern in the local population and media, and killed one tourist hiking the volcano. The great explosion formed a 4-km-high eruptive cloud, and its partial collapse ignited the dry vegetation and caused hot rock avalanches spreading along the northern slope to the sea and triggering a small tsunami wave. This paroxysm was followed by 56 days of lava flow effusion, and another explosive paroxysm occurred on 28 August 2019. Also this explosive event caused an eruptive column of about 4 km and hot avalanches spreading on the north flank of the volcano and on the sea surface. Here we use effusion rate time-series derived from MODIS and SLSTR data to follow the different thermal phases of this eruption and compute the dense rock equivalent volume emitted. At the same time we computed four digital elevation models from Pleiades triplets acquired on June, July, August and October 2019 in order to map the morphological changes occurred during the eruption. By differencing pre, syn and post eruptive topographies we computed the bulk lava volume at the different stages. Combining tri-stereo Pleiades results with MODIS and SLSTR ones, beside giving insights in the characterization of volcanic deposits, provides important constraints in the conversion between radiant heat flux and TADR, and demonstrates the powerful merging capability of multi-platform remote sensing data.
Proactive Drought and Extreme Event Preparedness: Seasonal Climate Forecasts offer Benefit for Decision Making in Water Management in Semi-arid Regions
Authors: Portele Tanja , Lorenz Christof , Laux Patrick , Kunstmann Harald
Published: March 2020

Semi-arid regions are the regions mostly affected by drought. In these climatically sensitive regions, the frequency and intensity of drought and hot extremes is projected to increase. With increasing precipitation variability in semi-arid regions, sustainable water management is required. Proactive drought and extreme event preparedness, as well as damage mitigation could be provided by the use of seasonal climate forecasts. However, their probabilistic nature, the lack of clear action derivations and institutional conservatism impedes their application in decision making of the water management sector. Using the latest global seasonal climate forecast product (SEAS5) at 35 km resolution and 7 months forecast horizon of the European Centre for Medium-Range Weather Forecasts, we show that seasonal-forecast-based actions offer potential economic benefit and allow for climate proofing in semi-arid regions in the case of drought and extreme events. Our analysis includes 7 semi-arid, in parts highly managed river basins with extents from tens of thousands to millions of square kilometers in Africa, Asia and South America. The value of the forecast-based action is derived from the skill measures of hit (worthy action) and false alarm (action in vain) rate and is related to economic expenses through ratios of associated costs and losses of an early action. For water management policies, forecast probability triggers for early action plans can be offered based on expense minimization and event maximization criteria. Our results show that even high lead times and long accumulation periods attain value for a range of users and cost-loss situations. For example, in the case of extreme wet conditions (monthly precipitation above 90th percentile), seasonal-forecast-based action in 5 out of 7 regions can still achieve more than 50 % of saved expenses of a perfect forecast at 6 months in advance. The utility of seasonal forecasts strongly depends on the user, the cost-loss situation, the region and the concrete application. In general, seasonal forecasts allow decision makers to save expenses, and to adapt to and mitigate damages of extreme events related to climate change.
Exit jet in a narrow Pyrenean valley: the Aure Valley 2018 field experiment
Authors: Paci Alexandre , Jiménez Maria Antonia , Cuxart Joan , Lothon Marie , Clary Olivier , Seity Yann , Martinez-Villagrasa Daniel , Dabas Alain , Rieutord Thomas , Román-Cascón Carlos
Published: March 2020

A field experiment took place from July to October 2018 in a narrow valley of the central Pyrenees in order to study local flows and their impacts.
This field experiment is a joint effort by CNRM, Laboratoire d'Aerologie and University of the Balearic Islands. It emerged from a recent numerical study done by the University of the Balearic Islands (Jiménez et al. 2019).
This study suggests that under clear-sky conditions a jet forms in the valley and can be observed several kilometers away from the valley exit.

Several instruments including a Doppler scanning lidar and three meteorological stations were deployed on the main site at the valley exit, where the jet maximum is expected, and on two other sites up valley. Data from the Atmospheric Research Center (part of the Pyrenean Platform for the Observation of the Atmosphere P2OA) in Lannemezan are also used. They include radio-soundings specifically planned for the field experiment. This instrumented platform of Laboratoire d'Aerologie, located about 10 km away from the valley exit, is an important asset for the project.

An overview of the field experiment as well as the valley exit jet main features will be presented. A comparison with outputs from the NWP model AROME will be also shown.
How reservoir regulation modifies the regional terrestrial-atmospheric water cycle: Incorporation of a reservoir network module into a fully-coupled hydrological-atmospheric model
Authors: Wei Jianhui , Dong Ningpeng , Arnault Joël , Fersch Benjamin , Wagner Sven , Zhang Zhenyu , Laux Patrick , Yang Chuanguo , Yang Qianya , Yu Zhongbo , Kunstmann Harald
Published: March 2020

The regional terrestrial-atmospheric water cycle is strongly altered by human activities. Among them, reservoir regulation is a way to spatially and temporally allocate the water resources in a basin for the purpose of, for example, flood control, agriculture development, ecosystem maintenance. However, it is still not well understood how the reservoir regulation modifies the regional terrestrial-atmospheric water cycle. To address this question, this study employs a fully-coupled regional Earth system modelling system WRF-HMS, which has a closed description of the water cycle in a ground-soil-vegetation-atmosphere continuum. A process-based reservoir regulation module is for the first time now implemented into WRF-HMS, which allows to represent reservoir regulation in one seamless atmosphere-hydrology modeling system. In addition, an online budget analysis of atmospheric moisture is implemented into WRF-HMS, so that the impact of reservoir regulation on the atmospheric branch of the water cycle is quantitatively analyzed. Our study focuses on the basin of the largest fresh water lake in China, the Poyang Lake basin. Four simulations with a horizontal resolution of 10 km are conducted for the investigation period of 1979 to 1986: the standalone HMS with/without the reservoir regulation module and the fully-coupled WRF-HMS with/without the reservoir regulation module. For the standalone simulations, the basin-averaged, multi-year mean results show that incorporating reservoir regulation leads to an increased evapotranspiration, a wetter soil, and a higher groundwater level. In addition, the interactions among river water, unsaturated zone, and groundwater are enhanced as well. Overall, the reservoir-enabled HMS model improves the streamflow simulation over the Poyang Lake basin on daily and monthly scales than the reservoir-disabled HMS model. For the fully coupled simulations, our preliminary results show that incorporating reservoir regulation also modifies the regional atmospheric branch of the water cycle, for example, moistening planetary boundary layer due to the enhanced evapotranspiration. Details about the results of the fully-coupled simulations will be presented in the conference.
Solubility of magnetite-hematite assemblages in slab-derived saline fluids
Authors: Tiraboschi Carla , Sanchez-Valle Carmen
Published: March 2020

In subduction zones, aqueous fluids derived from devolatilization processes of the oceanic lithosphere and its sedimentary cover, are major vectors of mass transfer from the slab to the mantle wedge and contribute to the recycling of elements and to their geochemical cycles. In this setting, assessing the mobility of redox sensitive elements, such as iron, can provide useful insights on the oxygen fugacity conditions of slab-derived fluid. However, the amount of iron mobilized by deep aqueous fluids and melts, is still poorly constrained.

We experimentally investigate the solubility of magnetite-hematite assemblages in water-saturated haplogranitic liquids, which represent the felsic melt produced by subducted eclogites. Experiments were conducted at 1 GPa and temperature ranging from 700 to 900 °C employing a piston cylinder apparatus. Single gold capsules were loaded with natural hematite, magnetite and synthetic haplogranite (Na0.56K0.38Al0.95Si5.19O12.2). Two sets of experiments were conducted: one with H2O-only fluids and the second one adding a 1.5 m H2O–NaCl solution. The capsule was kept frozen during welding to ensure no water loss. After quench, the presence of H2O in the quenched haplogranite glass was checked by Raman spectroscopy, while major elements were determined by microprobe analysis.

Preliminary results indicate that a significant amount of Fe is released from magnetite and hematite in hydrous melts, even at relatively low-pressure conditions. At 1 GPa the FeOtot quenched in the haplogranite glass ranges from 0.60 wt% at 700 °C, to 1.87 wt% at 900 °C. In the presence of NaCl, we observed an increase in the amount of iron quenched in the glass (e.g., at 800 °C from 1.04 wt% to 1.56 wt% of FeOtot). Our results suggest that hydrous melts can effectively mobilize iron even at low-pressure conditions and represent a valid agent for the cycling of iron from the subducting slab to the mantle wedge.
GammaEDU: an innovative tool for sensitizing society to natural radioactivity
Authors: Albéri Matteo , Bottardi Carlo , Chiarelli Enrico , Raptis Kassandra Giulia Cristina , Serafini Andrea , Strati Virginia , Mantovani Fabio
Published: March 2020

Environmental radioactivity is all around us, but the perception of the hazard deriving from this phenomenon is often altered by widespread negative feelings, misconceptions and the shortage of didactic paths dealing effectively with the topic. Ingenious methods for promoting knowledge exchange between researchers, general public and students are increasingly in demand. Traditional physics lessons need to embrace new smart technological tools more familiar to new generations.

We developed a powerful and stand-alone portable detection system called GammaEDU. This device operates autonomously to quantify the presence of radioactive elements in the environment through the detection of gamma rays emitted by their decays and can exchange data with users’ mobile devices via Bluetooth wireless connection.

Through the easy to use GammaEDU Android app the layman operator visualizes in real time the gamma ray spectrum acquired by the detector. The main spectrum structures are automatically highlighted by the software, which allows to take the GPS coordinates and shoot a picture of the surrounding environment. An automatic algorithm processes the acquired spectrum on-board, obtaining the estimated abundances of the different radioisotopes. The data are saved in a KMZ file reporting the measurement results ready to be visualized in a Google Earth and shared on cloud services or social-media applications.

GammaEDU was successfully tested during several educational activities to explore in-situ environmental radioactivity with the general public and with university and lower-level students. Thematic maps of natural radioactivity were created and found to be an effective educational tool for heightening awareness of natural hazards and break out of traditional communication approaches.
What’s that Floating in my Soup? Characterisation and Handling of Floating Debris in the Great Pacific Garbage Patch
Authors: Sulu-Gambari Fatimah , Egger Matthias , Lebreton Laurent
Published: March 2020

There is extensive documentation of plastic debris in the marine environment [1]. Citizen science programs and tracking apps have been used more recently in the collection of data on plastics in marine settings [1]. These programs, however, are focussed on debris collected from beach cleanups and coastal environments. Large debris currently afloat in ocean garbage patches, which contribute significantly to marine plastic pollution, are less well-characterised. Buoyant plastics accumulate offshore in the five ocean gyres, the largest of which is the Great Pacific Garbage Patch (GPGP) in the North Pacific Ocean. There, they are seen floating in a loosely concentrated ‘soup’. Over time they degrade in saltwater, under UV radiation, with the help of wind and wave action. They also serve as substrates for trace metal and organic pollutant adsorption, as well as the growth of microbial consortia and larger potentially invasive organisms. There is currently limited data collection on sources of large floating plastics in ocean gyres. Majority of data collected on plastics in the garbage patches is based on trawled sampling techniques that exclude objects larger than 0.5m [2]. Large debris are important for elucidation of the overall mass of plastic in the patches. We know that 8% of the GPGP is comprised of microplastics and thus larger objects constitute the greater fraction of the total plastic mass [2], which we know little about. It is important to understand what types of debris accumulate in the patches, their land-/marine-based origins and the locations from which they enter the ocean. Where the debris is produced and what practices (commercial, cultural, industrial) contribute to their accumulation in the garbage patches is also pivotal data that needs to be collected. This information, coupled to data on how long the plastics persist and how well they persevere in the marine environment, is necessary for creating effective and efficient mitigation strategies.

 

References

[1] Jambeck, J. R. & Johnsen, K. Citizen-Based Litter and Marine Debris Data Collection and Mapping. Computing in Science & Engineering, 17, 20-26 (2015).

[2] Lebreton, L. et al. 2018. Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic. Scientific Reports, 8, 4666 (2018).
Changes in the location of the nucleation point of slip events on ancient normal faults
Authors: Delogkos Efstratios , Childs Conrad , Manzocchi Tom , Walsh John
Published: March 2020

The lack of an unambiguous method for determining the propagation direction of slip events on faults over significant time periods limits our understanding of the long-term stability of fault slip propagation directions. A geological means for determining the propagation direction of slip events during the growth of faults is provided by mutually cross-cutting faults and bed-parallel slip-surfaces in the Ptolemais Basin, northern Greece.

In the Kardia lignite mine, Ptolemais Basin, bed-parallel slip surfaces intermittently offset the Quaternary faults as they grew to form discontinuities on otherwise continuous fault surfaces. Subsequent fault slip increments bypassed these discontinuities to re-establish a continuous fault trace and leave an associated ‘dead’ splay. The geometry and displacement distributions at these fault/bed-parallel slip intersections record the fault displacement at the time of bed-parallel slip and whether the next fault slip increment had an upwards or downwards component to its local propagation vector.

A database (N = 88) of slip propagation directions and fault throws was derived from continuous mapping of mine faces during lignite extraction over an eight year period. The data demonstrate a clear relationship between slip propagation direction and the accumulation of fault displacement on individual faults. During the early stages of fault growth, slip events propagated almost exclusively upwards through the mined sequence, but later stages of growth are marked by slip events showing both upward and downward components of propagation. The data therefore demonstrate that the location of the point of initiation of fault slip events on these Quaternary faults varied over the fault surfaces as the faults grew.

The emergence of systematic results from our analyses suggests that cross-cutting relationships between other synchronously active structures (e.g. conjugate faults) can provide a robust means for determining the propagation directions of slip events on ancient faults at outcrop.
Uncertainty in aerosol radiative forcing impacts the simulated global monsoon in the 20th century
Authors: Turner Andrew , Shonk Jonathan , Wilcox Laura , Dittus Andrea , Hawkins Ed
Published: March 2020

Anthropogenic aerosols are dominant drivers of historical monsoon rainfall change.  However, large uncertainties in the radiative forcing associated with anthropogenic aerosol emissions, and the dynamical response to this forcing, lead to uncertainty in the simulated monsoon response.  We use historical simulations in which aerosol emissions are scaled by factors from 0.2 to 1.5 to explore the monsoon sensitivity to aerosol forcing uncertainty (−0.3 W m−2 to −1.6 W m−2).  Hemispheric asymmetry in emissions generates a strong relationship between scaling factor and both hemispheric temperature contrast and meridional location of tropical rainfall.  Increasing the  scaling from 0.2 to 1.5 reduces the global monsoon area by 3% and the global monsoon intensity by 2% over 1950–2014, and changes the dominant influence on the 1950–1980 monsoon rainfall trend from greenhouse gas to aerosol.   Regionally, aerosol scaling has a pronounced effect on Northern Hemisphere monsoon rainfall.