bluuebunny/crossref_metadata_2025 huggingface dataset:
Techniques involving UV absorption spectroscopy for estimation of structural changes in soil organic matter
Authors: Lepane Viia , Otsep Helen , Szajdak Lech Wojciech , Szczepanski Marek
Published: March 2021

UV spectroscopy is extensively used for the quantitative analysis of natural macromolecules because of simplicity. As a qualitative method it is not very selective. The absorption spectra of organic macromolecules are generally broad bands without distinct peaks decreasing with the increasing wavelength making thus impossible to draw conclusions about exact chemical composition. However certain optical properties enable to obtain information about the organic matter transformation and changes in soils.

In present study soil samples from different depths were investigated by UV spectroscopic methods to measure the absorbance ratios at several wavelengths that could be related to chemical properties of the organic matter, for example the aromaticity, average molecular mass, functional groups, etc. The aim was to study the changes in structural characteristics of humic acids in soil profiles by using their UV absorbance ratios (A254/A436, A280/A350, A470/A664, A254/A354, A254/A204). The top layer of the soil was also characterized by comparing the structure of humic and fulvic acids and unfractionated dissolved organic matter. The spectra and molecular masses were additionally obtained by high performance size exclusion chromatography (HPSEC) with diode array detection.

Our results showed that there is a systematic change in the absorbance ratios at different wavelengths of humic- and fulvic acids and dissolved organic matter spectra in the soil profile that indicates to structural changes in the soil in time. The comparison of all fractions indicated that fulvic acid and unfractionated organic matter are structurally more similar to each other than to humic acid. Although the values obtained by two studied methods (UV spectroscopy and HPSEC) did not give the same values for the absorbance ratios, the correlations are mostly comparable and therefore, both methods can be used to estimate the changes of structural properties in soil.
Understanding the feedback of landuse practices and vegetation change in a Namibian savannah - a model assessment 
Authors: Irob Katja , Tietjen Britta , Balum Niels
Published: March 2021

Changing climatic conditions and unsustainable management strategies associated with biodiversity loss are perceived as major threats to Namibian savannahs. In the past, land-use in Namibia is dominated by livestock-farming as one of the major economic products. However, high grazing pressure led to degrading pastures in many regions in the country. In response, more farmers have recently shifted their land-use strategy from livestock to wildlife-based management, with so far unclear consequences for ecosystem dynamics. 
In this study, the ecohydrological, spatially explicit savanna model EcoHyD (Tietjen et al. 2009, 2010; Lohmann et al. 2012, Guo et al. 2016) was used to assess the impact of different land-use strategies on plant composition and ecosystem properties. The aim was to systematically evaluate the impact of different land-use strategies in terms of animal types and densities on the diversity of major plant groups (shrubs, perennial and annual grasses) and on several ecosystem processes. The results allow for identifying sustainable landuse strategies that avoid degradation and that lead to long-term provision of ecosystem services and economic income. 
We identified typical different functional plant types (PFTs) of the study region and parameterized the model to reflect the local environmental dynamics of the private game reserve Etosha Heights in Namibia. Afterwards, we run the model and assessed the composition and cover of our simulated PFTs, as well as water availability dependent on the land-use scenario. The results are in line with our expectations: they show that total plant cover increases with decreasing stocking rate and that cover and biodiversity are generally higher in browsing scenarios. In addition, we could explore, which PFTs of a given plant group are best adapted to grazing or browsing animals in a certain density. We could also show that perennial grasses benefitted more than shrubs from lower stocking rates. This benefit led to an improved soil water availability to plants, since less water was lost by overland flow, implying also a lower erosion risk. As the model has been applied to a variety of environmental settings regarding climatic conditions but also soil properties, we are confident that this study can serve as  blueprint to assess shifts in land-use also in other savannah systems. 
Open volcanic systems: evidence for deep gas loss
Authors: Collombet Marielle , Burgisser Alain , Colombier Mathieu , Gaunt Elizabeth
Published: March 2021

Previous studies of Vulcanian eruptive products have shown that the respective volcanic conduits were filled for the
most part with low-porosity magma prior to eruption. Comparison with the theoretical porosity distribution
expected from closed-system degassing suggests that gas loss must have taken place at great depth within the
magmatic column. At such high pressures, however, porosities are low enough to rule out traditional gas loss
mechanisms. We tested if channelling, an outgassing mechanism based on bubble connection due to high crystal
content proposed to occur in mushy magma reservoirs, could also happen in volcanic conduits. We reanalysed
phenocryst, microlite, and porosity data from recent eruptions of Merapi volcano, Indonesia, Soufrière Hills
volcano, Montserrat, and Tungurahua volcano, Ecuador. Overall, these magmas had crystal contents high enough
for outgassing to occur by channelling. Gases could be channelled out of the magma columns at various levels
during ascent to yield mostly gas-depleted magma columns prior to explosive behaviour. Such outgassing by
channelling has thus the capacity to influence eruptive style. Depending on the phenocryst content, microlite
growth during ascent can either foster, or impede gas escape by channelling. Considering the pervasive occurrence
of microlites and ensuing high crystal contents in volcanic conduits, the high likelihood of channelling implies that
other outgassing mechanisms might not be as dominant as previously envisioned.
Combining hydroeconomic modelling and bottom-up approaches for climate change adaptation. Application to the Jucar river basin (Spain).
Authors: Pulido-Velazquez Manuel , Marcos-Garcia Patricia , Lopez-Nicolas Antonio , Macian-Sorribes Hector , Rubio-Martin Adria
Published: March 2021

In many regions of the world, such as in the Southern Mediterranean area, water management has been challenging for long; however, climate change could act as an amplification factor and trigger an unprecedented situation. Several approaches have been proposed for the design of adaptation strategies for water resources systems. Although top-down approaches have been traditionally preferred, several authors have pointed out their relative lack of success when it comes to decision making. On the other hand, participative bottom-up approaches have the advantage of involving the stakeholders from the early stages of the strategy development, which could be crucial for the strategy's success. In order to overcome the shortcomings of both approaches and take advantage of their strengths, we propose a mixed bottom-up/top-down approach to define adaptation strategies at basin scale.

First, climate change impact on local water availability (future local inflows) is characterized using a top-down approach. Next, local knowledge is used through a participatory process in a bottom-up approach to foresight future scenarios of evolution of the agricultural sector and define locally relevant adaptation strategies. Each measure is characterized in terms of cost and efficiency. Water demands are characterized using economic demand curves. Finally, we used a hydroeconomic model to integrate the information obtained through top-down and bottom-up approaches to evaluate the net benefit of the different adaptation strategies, and select a socially acceptable and economically efficient program of measures for the climate and socioeconomic scenarios.

This methodology has been applied to the Jucar basin, a highly regulated basin with a fragile equilibrium between available water resources and demands. Climate change is expected to accentuate the current problems. The results show the importance of considering the spatial variability of climate change impacts in the basin. Temperature increase and precipitation decrease would be higher in the basin headwaters than in the coastal area, which conditions future inflows. In relation to adaptation measures, the stakeholders preferred the change from gravity to drip irrigation, the use of non-conventional water resources (wastewater reuse and desalination) and measures related to water governance. Finally, the results obtained from the hydroeconomic model show that, for most of the considered climate scenarios, the selected measures allow a significant reduction of the economic losses in the system.

Acknowledgements: This study has been supported by the ADAPTAMED project (RTI2018-101483-B-I00), funded by the Ministerio de Economia y Competitividad (MINECO) of Spain and with EU FEDER funds.
A global deforestation footprint from production and consumption of primary goods 
Authors: Vacchiano Giorgio , Lahoz Maria Giovanna , Ventrice Alessia , Bagliani Marco
Published: March 2021

Forests make over 30% of global land and perform functions of vital importance for the well-being of humans on Earth. Yet, forest cover is declining due to deforestation  that mainly affect tropical biomes, due to land use changes for agricultural, mining, and urban use to satisfy growing global demands. Globalization of markets and development have in fact raised the pressure on environmental resources by humans, and at least 30% of global deforestation is linked to the production of exported goods. 
We propose here a method to quantify the impact of global trade on forest cover, by assessing the deforestation embodied in the production, trade, and consumption of  forest-risk agricultural products and by-products. from 2000 to 2020. We provide the first estimate of a country-based deforestation footprint, an indicator of the pressure on forest cover by countries that consume goods produced on land previously occupied by forests.
This is a first attempt to systematically and critically address the issue taking into account responsibilities of both exporting and importing countries. Our methods and first assessment can support domestic and international policies aiming at reducing  deforestation through a correct assessment of a country's impact on global forests and their services. 
Magnetostratigraphic dating of late Miocene megalake regressions in Central Eurasia 
Authors: Krijgsman Wout , Palcu Dan , Patina Irina , Șandric Ionuț , Lazarev Sergei , Vasiliev Iuliana , Stoica Marius
Published: March 2021

The largest megalake in the record formed in Eurasia during the late Miocene, when the epicontinental Paratethys Sea became tectonically-trapped and disconnected from the global ocean. The Paratethys megalake was characterized by several episodes of hydrological instability and partial desiccation, but the chronology, magnitude and impacts of these paleoenvironmental crises are poorly known. The Panagia section on the Taman Peninsula of Russia is the only place known to host a continuous sedimentary record of the late Miocene hydrological crises of Paratethys. Paleomagnetic measurements allow the development of a polarity pattern that can be used to date the regression events. The Panagia polarity pattern consists of 17 polarity intervals, 9 of normal polarity and 8 of reversed polarity, plus 4 additional short-term polarity fluctuations, that are inferred to correspond to the 11-7.5 Ma interval. We identified four major regressions that correlate with aridification events, vegetation changes and faunal turnovers in large parts of Europe. Our paleogeographic reconstructions reveal that Paratethys was profoundly transformed during the regression episodes, losing ~1/3 of the water volume and ~70% of its surface during the most extreme events. The remaining water was stored in a central salt-lake and peripheral desalinated basins while vast regions (up to 1.75 million km2) became emerged land, suitable for the development of forest-steppe landscapes. The dry episodes of the megalake match with climate, food-web and landscape changes throughout Eurasia but the exact triggers and mechanisms remain to be resolved.
·         Pattern and time-scale dependencies of temperature-precipitation correlations in the Northern Hemisphere extra-tropics 
Authors: Herzschuh Ulrike , Böhmer Thomas , Cao Xianyong , Herbert Raphael , Dallmeyer Anne , Telford Richard , Kruse Stefan
Published: March 2021

Future precipitation levels under a warming climate remain uncertain because current climate models have largely failed to reproduce observed variations in temperature-precipitation correlations. Our analyses of Holocene proxy-based temperature-precipitation correlations from 1647 Northern Hemisphere extratropical pollen records reveal a significant latitudinal dependence, temporal variations between the early, middle, and late Holocene, and differences between short and long timescales. These proxy-based variations are largely consistent with patterns obtained from transient climate simulations for the Holocene. Temperature-precipitation correlations increase from short to long time-scales. While high latitudes and subtropical monsoon areas show mainly stable positive correlations throughout the Holocene, the mid-latitude pattern is temporally and spatially more variable. In particular, we identified a reversal to negative temperature-precipitation correlations in the eastern North American and European mid-latitudes during the mid-Holocene that mainly related to slowed down westerlies and a switch to moisture-limited convection under a warm climate. We conclude that the effect of climate change on land areas is more complex than the commonly assumed “wetter climate in a warmer world”. Future predictions need to consider that warming related precipitation change is time-scale dependent.
Compiling a chemistry database from Antarctic ice cores records spanning the past 2000 years
Authors: Vladimirova Diana , Thomas Elizabeth , CLIVASH2k on behalf of
Published: March 2021

Trends in sea ice extent and atmospheric circulation around Antarctica have exhibited large variability over recent decades. Direct observations such as satellite data cover the past four decades only. Thus, a comparison with paleoclimate archives is essential to understand the natural and anthropogenic components of these recent changes. We have initiated a data call within CLIVASH2k community (http://pastglobalchanges.org/science/wg/2k-network/projects/clivash) to collect all available sodium (Na+) and sulfate (SO42-) concentration and fluxes from Antarctic ice cores. We aim to improve our understanding of large-scale sea-ice variability and atmospheric circulation over the past 2000 years. In this respect, ice cores are a unique archive.

Here we present the new database, which builds on previous efforts by the PAGES community in gathering snow accumulation (Thomas et al. 2017) and stable water isotope data (Stenni et al. 2017).  To date, 88 published and 14 unpublished records have been submitted, 10 of which span the full 2000 years. The data, especially 2000 years-long records are equally distributed over the Antarctic continent and all coastal regions are well represented.  The new data will allow us to investigate interannual and decadal-to-centennial scale variability in sea ice extent and atmospheric circulation and its regional differences over the past 2000 years.
Impact of soil hydraulic properties on water-soil-plant relations
Authors: Javaux Mathieu , Carminati Andrea
Published: March 2021

Modeling stomatal response to soil drying is of crucial importance for estimating transpiration fluxes. There is a critical need for a better quantification of the impact of soil water limitation on vegetation in order to predict more accurately the impact of climate change on natural ecosystems and adapt agricultural practices.

Recently, we proposed a simple conceptual model, which predicts how soil and plant hydraulics affect transpiration.  This model reconciles soil- and root-based perspectives on drought stress and defines a 3D surface, which represents the maximum possible transpiration rate that can be sustained by a soil-plant system. The shape of this surface shows two distinct zones: a linear zone where the increase of transpiration is proportional to the difference of potential between soil and root and a non linear part in which an increase of E generates a huge decrease of leaf water potential. We show that this nonlinearity is mainly controlled by below ground hydraulic conductance. We hypothesize that plants should avoid this non linear zone by (1) adapting their short term stomatal regulation and (2) ensuring long term coordination between canopy and root hydraulics with growth. It implies that difference in soil hydraulics will lead to contrasted plant hydraulic and structural vegetation properties. Evidences exist at plant scales that this coordination exists. We further discuss how this might affect (agro-)ecosystem-water relations.    
Overcoming the complexity of drought by phasing drought triggers; a case study of Zimbabwe
Authors: Panis Marijke , Teklesadik Aklilu , Powell Mark , Muchena Richard , Muchatiza David
Published: March 2021

Historically droughts are one of the natural hazards in Zimbabwe with a significant impact on community resilience and threaten the livelihood of already vulnerable people. Agricultural activities are the primary source of income, where the dominant rain-fed agriculture is exceptionally vulnerable to climate extremes, reducing the country's agricultural productivity. The Zimbabwe Red Cross targets crop losses as the drought impact to prioritize in the drought impact-based forecasting system.

The Impact-based Forecasting project in Zimbabwe aims to reduce the impact of drought (crop losses) to the community by implementing early actions within sufficient operational lead time. Drought is a slow-onset disaster, and its impact is felt and visible at different moments  the seasonal calendar. This drought impact can be categorized into primary- and secondary impacts. Primary drought impacts are directly linked to rainfall scarcity, such as reduced crop yield and water scarcity. Secondary drought impacts are directly connected to dry conditions, such as food insecurity and epidemics. These temporal differences of impacts ask for drought triggers at various moments in the calendar, leading to a more segmented approach. The segmented approach makes it possible to design the trigger in a way that the drought indicators best linked to the operational early action at that lead time. The first phase has the longest lead time in predicting the impact of a drought using a global climatological indicator (ENSO) first to identify the probability of an El Niño/La Niña year to develop into the next growing season. Secondly, the FEWSNET Food Security Seasonal Outlook can be used as a predictor of the impact of an upcoming drought and of the population exposed to an IPC-Class 3 level. The last phase exists of monitoring biophysical drought indicators over the growing season to predict accurately the effect of a drought with the shortest lead time. The aim of phasing the trigger methodology is to activate low-cost actions when the uncertainty of the impact of a drought is relatively high. By adding more seasonal information to the trigger model over time, the predictive uncertainty reduces.

As a result, the drought trigger methodology we designed can drive the discussion and be the evidence base on the selection of early actions to reduce drought impacts. Next steps in the development of the system are to calculate the forecast skill of the biophysical indicators such as standardized precipitation index (SPI) and Vegetation Condition Index (VCI) soil moisture? linked to the identified prioritized drought impacts and to select corresponding early actions.
Towards a dynamic approach of sequences of coral reef terraces
Authors: Pastier Anne-Morwenn , Malatesta Luca , Huppert Kimberly , Chauveau Denovan
Published: March 2021

Sequences of coral reef terraces result from the interplay between biogenic and clastic sedimentary production, relative sea level (RSL) variations, wave erosion and tectonic forcing. Reefal sequences are gold standard proxies for paleo-sea level and tectonic reconstructions, but their contribution is usually restricted to a bijective approach, correlating the single elevation and age of their inner edge to single sea level stands or coseismic offsets, and reciprocally. The increase of available data, such as coral datings and high resolution topography revealed major deviations from this bijective approach (corals from a single MIS on several terraces, and conversely, or MIS highstands not represented in a sequence).

The Cape Laundi sequence, Sumba island, Indonesia, demonstrates such deviations, with outcrops of corals from MIS 5e on as many as three terraces instead of a single terrace as commonly expected. A preliminar numerical model of coral reef terrace profile has been developed, integrating reef growth, wave erosion, RSL variations and tectonic deformation. The interplay between reef growth rate, tectonic displacements and RSL variations provides a plausible explanation for these numerous occurrences. The low growth rate of this reef appears to prevent coral from  saturating the accommodation space generated during sea level transgression, leading to the preservation of drowned platforms and reefal construction of similar age during regressions.

Preliminary results from numerical modeling reveal complex feedbacks between the processes shaping these morphologies. Tectonic deformation has a major influence on reef development, by favoring reef preservation at high uplift rates and controlling the available accommodation space for reef growth.. By taking into account the numerous feedbacks controlling reef morphology, we can investigate the significance of RSL variations, continuous and punctual rock uplift, biogenic activity, and clastic inputs on coral terrace morphology and chronostratigraphy. Our approach can bring crucial constraints to the rates and frequency of RSL variations. To do so, we further develop our numerical model in order to provide more robust insights on the controls of reefal sequences morphologies. 
A daily to seasonal Arctic sea ice forecasting AI
Authors: Andersson Tom R. , Hosking J. Scott , Krige Eleanor , Pérez-Ortiz Maria , Paige Brooks , Elliott Andrew , Russell Chris , Law Stephen , Jones Daniel C. , Wilkinson Jeremy , Phillips Tony , Tietsche Steffen , Sarojini Beena Balan , Blanchard-Wrigglesworth Ed , Aksenov Yevgeny , Downie Rod
Published: March 2021

Arctic sea ice forecasting is a major scientific effort with fundamental challenges at play. To address such challenges, we have developed a physics-informed, data-driven sea ice forecasting system, IceNet, which outperformed a leading dynamical model (ECMWF SEAS5) in monthly-averaged forecasts of pan-Arctic sea ice concentration. IceNet adopted a U-Net deep learning architecture and was trained on over 2,000 years of CMIP6 climate simulation data. Despite its state-of-the-art seasonal forecasting skill at lead times of 2-6 months, IceNet has two main limitations. First, it could not outperform the dynamical model in short-range (1-month) forecasts. This is partly caused by IceNet operating on monthly-averages, which smears the initial conditions and weather phenomena that can dominate predictability at short time scales. Second, IceNet is afflicted by the ‘spring predictability barrier’ that affects all long range forecasts of summer. This predictability barrier arises primarily due to the importance of melt-season ice thickness conditions on summer sea ice. Here we present our early findings from IceNet2, which attempts to alleviate these issues by operating on daily-averages and including sea ice thickness as an input variable. IceNet2 paves the way for our efforts to aid the Arctic conservation community by developing the first public, operational sea ice forecasting AI.
Looking for the hidden morphological signature of active faults in a Low Strain Rate region: clues from the eastern Kachchh region (NW India) 
Authors: Srivastava Eshaan , Parrino Nicolò , Malik Javed , Pepe Fabrizio , Burrato Pierfrancesco
Published: March 2021

The Kachchh region (NW India), a pericratonic rift basin delimited by E-W trending major thrust faults, is a Low Strain Rate region[PB1] . In this area, the tectonic forcing magnitude is stronger enough to trigger infrequent significant earthquakes but not enough to overprint the climatic forcing signature. As a consequence, the active faults sources of the largest seismic events are largely poorly known and their geomorphic signature is subdued. 

Instrumental and paleoseismological evidence highlights that the eastern part of Kachchh experienced a significant number of seismic events such as the 1819-06-16 Allah Bund earthquake (Mw 7.8, also known as the Rann of Kutch earthquake), the 1956-07-21 Anjar earthquake (Mw 6.1), the 2001-01-26 Bhuj earthquake (Mw 7.6) and the 2006 events (Mw 5.0 and 5.6 earthquake occurred along Island Belt Fault and Gedi fault). 

In this region, the unavailability of useful outcrop information due to a significant climatic overprinting of the fault’s morphological signatures hampers the detection and parametrization of actively deforming faults.

For this reason, in this ongoing work, we propose a multidisciplinary approach, aimed at detecting active geological structures and their related [PB2] surface deformation, which mainly consists of quantitative tectonic geomorphology and paleoseismological analyses and structural interpretation and modelling. Preliminary results are a morphotectonic evolution model and 3D fault model of the study area. Finally, we stress the concept that only a multidisciplinary approach could provide useful information to understand better the highly debated active tectonic framework of the study area.
Carbon stock changes through dryland rehabilitation: a case study from central Jordan’s agro-pastures
Authors: Hall Liam , Haddad Mira , Strohmeier Stefan , Rawashdeh Hamzeh , Bani-Hani Nabeel , Al-Widyan Jafar , Hasan Hazem , Sterk Geert
Published: March 2021

Land cover, productivity and carbon stocks are among the widely acknowledged indicators of the land’s degradation and development status. The indicators’ assess-ability, however, differs across global ecosystems and location. Despite the complexity of carbon stocks, soil carbon in particular is receiving increasing attention for its potential in both climate change mitigation and economic growth in developing carbon markets. 
The degraded drylands of Jordan have been targeted by multiple investment programs to rehabilitate their arid agro-pastures, including through the application of mechanized micro-water harvesting structures combined with the plantation of native shrub seedlings. Whilst both local and remote land cover and biomass change monitoring indicate variable rehabilitation success, the related carbon stock changes remain largely under-investigated and unclear.
An international research consortium designed and implemented a study to investigate the actual and potential future carbon stocks per ecosystem status at an agro-pastoral research site located in central Jordan’s ‘Badia’, considering both conventionally managed (degraded) and rehabilitated lands. Field experiments conducted by scientists and  local and former tribal community collaborators were combined with carbon modeling using RothC. This enabled the development of multiple scenarios considering both natural and enhanced, or human induced, processes; for example, through landscape modification (mechanized micro-water harvesting), vegetation plantation as well as optional soil amendment through biosolids. Preliminary results suggest that the implementation of water harvesting structures leads to a pronounced increase in soil carbon sequestration when compared to baseline conditions of between 15% and 45% over a 5 year period , with work ongoing to quantify the uncertainties around these results. The selected rehabilitation scenarios match the criteria for vast potential upscaling across global drylands. The study outcomes will eventually support a comprehensive ecosystem services valuation approach with (soil) carbon as an integral factor and moving towards reversing degradation and crediting the dry ecosystem’s values beyond their marginal agricultural services.
Nowcasting for urban flash floods in Africa: a machine-learning and satellite-observation based model
Authors: Lugt Dorien , van Hoek Mattijn , Meirink Jan Fokke , van der Kooij Eva
Published: March 2021

On the world’s fastest urbanizing continent, Africa, urban floods are a real and growing problem. Early warning is the first important step in flood risk management. This requires continuous and reliable precipitation measurements and forecasts, which are not always available in African cities.

In this study a nowcasting model based on Convolutional Neural Network (TrajGRU) was developed for short-term, 0-2 hours, precipitation forecast in Ghana, West Africa. The nowcasting model is trained on historical rainfall estimates derived from the MSG-SEVIRI instrument by the Nighttime Infrared Precipitation Estimation (NIPE) model. Input for the model are real-time NIPE MSG-SEVIRI estimates.

The Meteosat Second Generation (MSG) SEVIRI instrument provides high-resolution and short-latency data, covering Europa and Africa. Especially in areas without radar observations, MSG offers unique and relevant information for early warning with respect to fast occurring events such as urban flash floods. Its resolution allows for the retrieval of convective rainfall, often a cause of flash floods in tropical areas.

To assess the performance of the model, we compare our method to current state-of-the-art Lagrangian nowcasting system from the pySTEPS library applied to the NIPE-MSG-SEVIRI data.

The result is an operationally running model for nowcasting two hours ahead with 15 minutes temporal and approximately three kilometer in Ghana (rainsat.net). The method is readily applicable in other regions in Africa.
Navigation in Greece: Developing a methodology for the spatial allocation of emissions
Authors: Fameli Kyriaki - Maria , Papadopoulos Evangelos , Assimakopoulos Vasiliki
Published: March 2021

Due to its complex topography (many islands) and extended coastline, Greece has numerous ports (about 200) which serve both commercial and touristic purposes. Almost 85 of them were in use in 2017. According to the FEI-GREGAA emissions inventory, navigation accounted for the 12% to the annual NOx emissions and by 3% to the PM10 emissions in 2017. Consequently, it is an important source of emissions especially for areas which are close to major ports, such as the Athens basin; because it affects the local air quality (almost 32% of total NOx emissions in Athens for the year 2017 came from shipping).

In this study a comprehensive emissions inventory for the navigation sector was developed covering the period 2006 – 2017 and used as input to a photochemical model study.  The shipping emissions were calculated for each Greek port and ship type based on the ship arrivals. The relevant data for each ship type were provided by Eurostat in seasonal basis. The methodology followed was the Tier 2 approach suggested by the EMEP/EAA emissions inventory guidebook. Harbour (hotelling and manoeuvring) and cruise emissions of both the main and auxiliary engine were calculated for the main pollutants (such as NOx, NMVOCs, CO, etc), particulates (PM10, PM2.5), heavy metals (e.g. Pb, As, Cr, Zn), PCB and HCB.

In Greece the movement of passenger ships is very frequent. Consequently the spatial disaggregation of emissions was carried out with two different methodologies. Emissions from passenger ships were distributed on the ferry lines, as these have been recorded by OpenStreetMap, in which the necessary completion was made in order to cover the itineraries of the ships in all the Greek islands. The emissions from the other ship categories were distributed in the coastal zones around the respective ports, considering the probability of being in the specific zones significant. Finally, a part of the total emissions (10%) was placed in the ports.

Results revealed that in 2017 NOx emissions (27.5 ktonnes) prevailed among other pollutants contributing by 69% to the total maritime emissions, while SOx emissions followed (16%). This is due to the use of diesel fuel. Concerning the annual variation of pollutants for the period 2006 – 2017, it was found that in 2011 there was a significant reduction of emissions compared to 2010 (9,921 ktonnes for NOx and 3,913 ktonnes for sulfur oxides - SOx) while the decrease was lower for the rest pollutants. From 2012 onwards, the results showed a stabilization trend. The majority of pollutant emissions are attributed to the port of Piraeus (3704.7 ktonnes NOx emissions from passenger ships), which is the busiest passenger and commercial port in Greece (20228 passenger ships and 3168 container ships arrived in 2017).
Near-real-time identification of the drivers of deforestation in French Guiana
Authors: Ballere Marie , Mermoz Stephane , Bouvet Alexandre , Koleck Thierry , Le Toan Thuy
Published: March 2021

Tropical forests account more than 50% of recorded terrestrial biodiversity and play an important role in carbon storage and the water cycle. The degradation of tropical forests presents an immediate danger for the global environment and biodiversity. Monitoring of deforestation and understanding its drivers are challenging tasks that are essential to measures of reduction of deforestation.

Many researches have been carried out on the detection of deforestation using remote sensing data, and there are several operational systems that work. Those systems are mostly based on optical data, but they show big delays in detections due to the persistent cloud cover in the tropics. Since 2014, Sentinel-1 provides SAR images every 6 to 12 days, insensitive to cloud cover. Deforestation detection methods based on SAR images have increased and start to be operational (Bouvet et al. 2018, Reiche et al. 2021). They allow for faster and more accurate mapping. For example, Ballere et al. 2021 shows that 80% of gold-mining-related deforestation in French Guiana is first detected by a SAR-based method, before the optical method, most often offset by several months.

However, the detection of disturbances in itself is not sufficient for measures to halt deforestation. Finer et al. 2017 defined a 5 steps protocol in order to help the near-real-time monitoring to be effective, the first step being the detection. Then comes the prioritization of data: this can be done by integrating spatial data such as protected areas or specific areas of interest. The third step is the identification of the drivers. This usually involves human-work.

We present here an automatic method for the identification of the drivers of deforestation in French Guiana (gold mining, urbanization, small-scale agriculture and forest exploitation), and show its results. It is based on geographical and morphological indicators, and makes it possible not to wait for another image after the detection step. The method has the potential to be integrated into an operational system for French Guiana.
Synthetic seismic modeling and inversion for the Oldoinyo Lengai volcanic complex.
Authors: komeazi Abolfazl , Zhang Yi , de Siena Luca , rümpker Georg , Kaus Boris , Reiss Miriam , Castro César , Spang Arne , Hering Philip , Junge Andreas , Baumann Tobias
Published: March 2021

What is the effect of crustal melt accumulation on the seismic wavefield? Can we reproduce the dispersion, scattering and associated stress-anisotropy with modeling tools? By performing numerical experiments of seismic wave propagation in a synthetic and geodynamically-consistent volcanic system we can test our ability to model the seismic wavefield and to reconstruct the target “magma chamber”.

We built a synthetic volcano based on recent seismic observations at the Oldoinyo Lengai volcanic complex. The velocity model  is based on a geodynamic model that provides shear modulus, Poisson's ratio, and density. The isotropic P- and S-wave velocities can be computed directly from these parameters. To test a more realistic depth dependence, we introduced a reference 1D velocity model for Northern Tanzania and expanded this to 3D. Then, we inserted variations in the rock parameters mimicking a magma chamber and resolved it using the Fast Marching Travel Time tomography code.

To further our understanding, we also added  3D anisotropy and random velocity fluctuations to the system, acting both as synthetic input for future applications and testing of seismic techniques (e.g., shear wave splitting analysis) and as noise for the travel time tomography. For the waveform modeling we used the velocity-deviatoric stress-isotropic pressure equations together with perfectly matched layers. Also, we encoded the boundary condition between solid and air in this formulation. The 25 receivers with their real geographic locations were placed for inversion sensitivity analysis. In particular, the ability to reconstruct the magma chamber and the effect of anisotropy and velocity fluctuations at frequencies up to 5 Hz are evaluated. The results are compared with a parallel forward modeling and inversion of synthetic MT data. To confirm our results and as an additional test, we also employ adjoint tomography based on spectral element method to implement a forward waveform modeling and inversion using the tools provided in the SPECFEM3D_Cartesian package.

The results present a better idea of how to construct a realistic synthetic volcano in the future. By combining multiple seismic forward models and inversion approaches, this study yields insights into the sensitivity of the seismic wavefield to geodynamically-consistent volcanic structures.
Exploring ice core sea ice proxies through process-based modelling
Authors: Rhodes Rachael , Yang Xin , Wolff Eric
Published: March 2021

It is important to understand the magnitude and rate of past sea ice changes, as well as their timing relative to abrupt shifts in other components of Earth’s climate system. Furthermore, records of past sea ice over the last few centuries are urgently needed to assess the scale of natural (internal) variability over decadal timescales. By continuously recording past atmospheric composition, polar ice cores have the potential to document changing sea ice conditions if atmospheric chemistry is altered.  Sea salt aerosol, specifically sodium (Na), and bromine enrichment (Brenr, Br/Na enriched relative to seawater ratio) are two ice core sea ice proxies suggested following this premise.

Here we aim to move beyond a conceptual understanding of the controls on Na and Brenr in ice cores by using process-based modelling to test hypotheses. We present results of experiments using a 3D global chemical transport model (p-TOMCAT) that represents marine aerosol emission, transport and deposition. Critically, the complex atmospheric chemistry of bromine is also included allowing us to explore the partitioning of Br between gas and aerosol phases.  
Environmental monitoring of riverine plastic contamination in Asia
Authors: Olsen Marianne , Hurley Rachel , Buenaventura Nina , Eidsvoll David , Braaten Hans Fredrik , Lin Yan , Steindal Eirik , Nizetto Luca , Larssen Thorjørn
Published: March 2021

Rivers have been identified as an important pathway for the release of plastic waste to the oceans, connecting land-based sources to the marine environment. Asian rivers, in particular, have been highlighted by several published studies as contributing a considerable proportion of global macro- and microplastic release. To evaluate this, several parallel projects (ASEANO, SINOPLAST, INOPOL) have commenced environmental monitoring of riverine plastic contamination in China, India, and several ASEAN countries. Monitoring is being undertaken in selected study catchments, which have been identified based on their geographical context and their relevance to global plastic contamination. They include several rivers that have been reported as being amongst the most contaminating systems in the world. Macroplastic flows in the active river channel will be assessed, as well as the role of the riverbank zone in the storage and transport of plastic waste. Monitoring of riverine microplastic contamination will also be included in some countries. The aims of this environmental monitoring is to: i) provide estimates for the flux of plastics to the ocean; ii) identify appropriate and optimum methods for routine monitoring of riverine plastic contamination; iii) supply qualitative and quantitative data on macroplastic flows and contamination to support social science research that is also taking place within these river catchments; and iv) provide data for the calibration and validation of riverine plastic transport models.

This presentation will give an overview of monitoring plans and preliminary findings and experiences from these ongoing projects. This will include a discussion about the ways in which monitoring methods have been adapted to river systems with different morphologies and flow regimes, and to satisfy different research questions across the projects. The complexities associated with undertaking environmental monitoring in large river systems will also be addressed.
A new high resolution Mean Sea Surface (DTU21MSS) for improved sea level monitoring
Authors: Andersen Ole Baltazar , Abulaitijiang Adil , Zhang Shengjun , Rose Stine Kildegaard
Published: March 2021

A new Mean Sea Surface (DTU21MSS) for referencing sea level anomalies from satellite altimetry is presented. The major new advance leading up to the release of this MSS the use of 5 years of Sentinel-3A and an improved 10 years Cryosat-2 LRM+SAR+SARin record including retracked altimetry in Polar regions using the SAMOSA+ physical retracker via the ESA GPOD facility.

A new processing chain with updated editing and data filtering has been implemented. The filtering implies, that the 20Hz sea surface height data are filtered using the Parks-McClellan filter to derive 1Hz. This has a clear advantage over the 1 Hz boxcar filter in not introducing sidelobes degrading the MSS in the 10-40 km wavelength band. Similarly, the use of consistent ocean tide model for the Mean sea surface improves the usage of sun-syncronous satellites in high latitudes.

The presentation will also focus on the difficult issues to consolidating Cryosat-2 and Sentinel-3 onto a past 20 year mean sea surface. This is implemented using simultaneous estimation of the mean, sea level trend and annual and semi-annual variations in sea level.  
Temporal evolution of C stock in soils from the cork oak forest in a post-fire scenario
Authors: Almeida Patricia , Santos Erika S. , Arán Diego , Acácio Vanda , Duarte Inês , Lerma Victoria , Rego Francisco
Published: March 2021

Forest fires are increasing their recurrence, intensity and scale in Portugal, increasing also the vulnerability of this region of Southwestern Europe to the impacts of the climate change. In Portugal, several studies have been focusing the dynamic of cork oak forest after fires from tree level to landscape level. However few information is available about the impact of wildfires in the soil quality, namely C stock, and its evolution. This component of the ecosystem and the evolution of its characteristics can be related with the dynamics of the landscape in the post-fire period and its knowledge can help in the management and rehabilitation of plant-soil system.

Serra do Caldeirão is located in Algarve region (S of Portugal). The soils are classified as Leptosols with low fertility. The landscape is characterized by cork oak forests with shrub cover which is dominated by Cistus species. To assess the distribution of total organic C in the study area, several soil sampling were intersected, on two sampling dates (2012 and 2013), with the vector information of the burned area in 2004. This information was intended to assess the temporal evolution of C concentration, depending on its location in a burnt or non-burnt area.

In general, the burnt areas showed greater variability of C concentrations in soils collected in both the years, with maximum values ​​of 33.0 g/kg for 2012 and 36.5 g/kg for 2013. These maximum values ​​exceed those obtained for soils in non-burnt areas. Despite of this scenario, and independently of the year, no statistically significant differences were found in the C concentrations of the burnt plots and the control plots. For other chemical characteristics (e.g. nutrients), the variations depended on the area. Implementation of post-fire recovery measures and forest management of the areas can justify this variation.

Acknowledgment: This work is co-financed by project REMAS (SOE3/P4/E0954) from Interreg SUDOE 2014-2020 program and is also financed by the FEDER Funds through the Operational Competitiveness Factors Program - COMPETE and by National Funds through FCT - Foundation for Science and Technology within the scope of the project  UID/AGR/04129/2020 (LEAF) and  the project UID/BIA/50027/2019 (CEABN/InBIO).
Small-scale geological mapping on Earth: Setting up guidelines, standards and portrayal rules. Experience from pan-European projects
Authors: Asch Kristine
Published: March 2021

Geological mapping and cartography on Earth encompasses principally the description of the landforms, i.e. geomorphology, the lithology and the age (stratigraphy) of the rocks found at or beneath the Earth’s surface. By interpretation of this information genetic information (process, event and environment) can be derived from the rock units encountered and often is included in geological maps, in particular in larger scale maps.

Mapping agencies and geological survey organisations everywhere have for centuries been developing their own regional or national mapping methods and representation colour sets and symbols to represent the geological information on paper and now in spatial databases and GIS.

BGR and its predecessors has been undertaking geological mapping at both large and small scales since the 19th century and through this has gained considerable mapping experience. This contribution describes the establishment of mapping rules and guidelines for three small-scale European cross-boundary mapping projects implemented through international cooperation: the IGME 5000 (pre-Quaternary) and the IQUAME (Quaternary) projects, and the EMODnet Geology seafloor work-package. The experience gained within the projects in the creation and use of standardised specifications for data models and cartographic aspects such as symbols and colours will be introduced and challenges, advantages and disadvantages  will be discussed.

All three projects include off-shore geological information; in particular these aspects of the marine mapping and cartography may be partly comparable to planetary mapping, since “even with all the technology that we have today -- satellites, buoys, underwater vehicles and ship tracks -- we have better maps of the surface of Mars and the Moon than we do the bottom of the ocean.” [Gene Feldmann, NASA, 10.08.2009].

Thus the experience and results in Earth mapping described may contribute and serve as “good practise” for the benefit of the fascinating new field of planetary mapping.

 