bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dynamic History of the Saharan Desert revealed by 11 Million Years of Exported Dust
Authors: Crocker Anya , Naafs B. David , Westerhold Thomas , James Rachael , Cooper Matthew , Röhl Ursula , Pancost Richard , Osborne Colin , Beerling David , Wilson Paul
Published: March 2020

The Sahara is the largest hot desert on Earth and the source of about half of the world’s atmospheric dust which acts to fertilize the Atlantic Ocean and Amazon Basin. The timing and cause of Saharan desert inception are vigorously debated, but northern Africa is widely suggested to have dried progressively with global cooling through the late Cenozoic, favoring both desert and C4-grassland savanna expansion. We present a wide range of data, encompassing sediment geochemistry and grain size distributions, plant wax isotopic signatures and lithogenic radiogenic isotopes to explore when and why desert conditions were established on North Africa. Our work on North Atlantic deep-sea sediments reveals persistent waxing and waning of Saharan dust input, with astronomically forced aridity in the interior of northern Africa more than three times earlier than the widely invoked date for the onset of desert conditions and no major changes in dust source regions over the last 11 Myr. This result strongly suggests that the Saharan desert is older and more dynamic than previously documented. Our data also challenge suggestions of a simple long-term escalation of northern African aridity driving an associated grassland expansion and provide a new framework from which to assess floral and faunal evolutionary outcomes on Africa, including the expansion of the C4-savanna ecosystem and the development of our hominid ancestors.  
A merged CryoSat-2 Sentinel-3 freeboard product, its sensitivity to weather events, and what it can tell us about Ku-band radar penetration
Authors: Lawrence Isobel , Armitage Tom , Shepherd Andrew , Tsamados Michel
Published: March 2020

The co-existence of satellite missions provides a unique opportunity for making novel observations not possible with a single satellite. Here we process data from CryoSat-2, Sentinel-3A and Sentinel-3B satellites for the 2018-19 and 2019-20 winters. Basin-average radar freeboards from Sentinel-3A/B are shown to agree with CryoSat-2 to within 3mm. A merged product is developed combining data from the CryoSat-2 and Sentinel 3A/B missions, permitting basin-wide observations of Arctic sea-level anomaly and radar freeboard at synoptic time-scales. A comparison of 9-day radar freeboard variability with snowfall data from ERA5 reanalysis reveals a strong positive correlation over first-year ice, a result which appears to contradict traditional assumptions of Ku-band radar penetration of snow. A detailed spatial analysis including a comparison of freeboard before and after the passage of storms reveals for the first time the ability to detect synoptic scale weather events in the satellite radar freeboard record.
What drives the isotopic composition of vapor, precipitation and surface snow in a coastal site of East Anrctica: Adelie Land
Authors: Leroy-Dos Santos Christophe , Landais Amaelle , Fourre Elise , Agosta Cecile , Casado Mathieu , Orsi Anais , Aufresne Gregoire , Jossoud Olivier , Prié Frederic
Published: March 2020

Studying the drivers of the water stable isotopic composition at coastal Antarctic sites is useful for the interpretation of coastal ice-core signal or the analysis of recent mass balance evolution. In addition to the classical fingerprint of temperature, the water isotopic composition in water vapor and snow carries a fingerprint of the humidity transport pathway, from evaporation to precipitation. Blowing snow in very windy coastal regions is also expected to carry a particular signature affected by snow-air exchanges as observed for surface snow on the East Antarctic plateau.

Since November 2018, we have been continuously measuring the water stable isotopic composition of vapor at Dumont D’Urville station (Adélie Land) using laser spectrometers in addition to isotopic composition of precipitation, blowing snow and surface snow samples. We present here the full 2019 data series. We focus on the two main weather regimes, in summer and winter, that affect the local hydrological cycle. In summer, temperature and specific humidity signals are characterized by large diurnal cycles due to katabatic winds. Winter variability is largely influenced by large scale synoptic events. We also investigate a few specific cases of precipitation/sublimation and compare two summer periods with opposite sea-ice conditions.
Spatio-temporal dynamics of flood regulating ecosystem services in the Arno river basin, Italy
Authors: Mori Stefano , Pacetti Tommaso , Brandimarte Luigia , Caporali Enrica
Published: March 2020

Human activities can strongly influence the capacity of ecosystems to provide flood regulating ecosystem services (ES). Therefore, the effects of land use alteration, population migration and urbanization are key aspects to be considered when dealing with flood management. This study aims at analyzing the spatio‑temporal dynamics of flood regulating ES to support watershed management planning. The spatial explicit analysis of flood regulating ES is carried out with SWAT - Soil and Water Assessment Tool, using daily meteorological data between 2000 and 2014. Two indicators are elaborated in order to evaluate the retention capacity of each land use setting and to map the ES supply. Demand quantification is obtained from the information derived by the existing flood management plans (i.e. PAI-Piano per l’Assetto Idrogeologico and PGRA-Piano di Gestione del Rischio Alluvioni) which contain the identification and the perimeter of hydraulic hazard classes. Supply and demand data are then merged in order to obtain budget maps of flood regulating ES and their evolution from 1960 up to 2012 (1960, 1990, 2000 and 2012). The results show that both the demand and the supply of ecosystem services change during the time. With the increasing urbanization, the demand values have grown in the Arno floodplains, where residential, industrial and commercial zones are located. At the same time, land use changes (e.g. intensive agriculture) have caused negative effects on water regulation supply. This work shows the advantages of assessing flood regulating ES to improve flood regulation in the Arno river basin and provide a sound base of knowledge to identify floods prevention and mitigation measures.
Hands-On Demonstrations for Natural Hazards
Authors: Malamud Bruce D. , Taylor Faith
Published: March 2020

Here we present several teaching demonstrations and hands-on activities for natural hazards. Many methods exist to actively involve students and local community participants, particularly when numbers are large, so that teaching is not just `receiving of information' via monologue talks and using powerpoint. These methods include (a) breaking up into small group discussions, (b) group ‘role playing’ exercises, (c) serious games, (d) hands-on activities, and (e) class demonstrations. This paper concentrates on the latter and includes demos/activities for (a) earthquakes, (b) landslides, (c) tsunamis, (d) volcanoes and (e) weather. Natural hazards demonstrations/activities presented here are mostly inexpensive, have been used in front of large university classes and smaller `break-out groups', and are also appropriate for secondary-school students, university students, and local community communications. We have found that as a teaching tool, students and community participants often become much interested and more excited about what they are learning if use is made of these 5-10 minute class demonstrations or activities, even if only peripherally related to the subject at hand. Resultant discussion with questions and comments by students keeps both the students and the lecturer motivated and intrigued about the subjects being discussed. Days, weeks, and months later, the students remember these `demonstrations', but to set these up takes time, effort, and resources of equipment, although not necessarily a large amount of the latter.
Potentially catastrophic precipitation events and associated weather types in the western Mediterranean area
Authors: Insua-Costa Damián , Miguez-Macho Gonzalo , Lemus-Canovas Marc , Llasat María Carmen
Published: March 2020

The western Mediterranean region (WMR) often suffers from the devastating effects of flooding, caused by enormous rain accumulations that sometimes resemble the values produced by tropical systems. The ensuing socio-economic impact is so high that some of these extreme precipitation events are remembered and studied for decades. The main underlying reason for the high frequency of flooding in the WMR is that its precipitation regime presents a strong seasonality, with a maximum in late autumn associated with the development of strong convective situations that give rise to relatively short but intense periods of rain.

Here, we use the MESCAN precipitation analysis to detect daily heavy precipitation events in the WMR for the period 1980-2015. We consider a particular day as extreme if the precipitation for that day exceeds a threshold, which is based on normalized daily precipitation anomalies combined with a constant value.  The selected events are ranked according to their magnitude, defined on the basis of the amount and intensity of rain as well as the total extent affected. We then associate a weather pattern to each detected event. The methodology used to classify extreme days by weather types is based on a principal component analysis (PCA) approach. Specifically, we apply a PCA to a temporal mode matrix of 500 hPa geopotential height and mean sea level pressure, both obtained from ERA-5 reanalysis data. Our results show that the atmospheric configurations leading to torrential rainfall in the WMR are very reduced and recurrent; only four weather types are present in most of the extreme days. One of the main novelties of this study is that we can distinguish between more and less intense cases, so we were able to ascertain that only two of these four weather types are responsible for the majority of the most severe cases.
The 2019 July Stromboli volcano paroxysm event: contribution of infrasound to the Volcanic Ash Advisory Centers
Authors: Marchetti Emanuele , Ripepe Maurizio , Le Pichon Alexis , Listowski Constantino , Ceranna Lars , Hupe Patrick , Pilger Christoph , Matos Sandro , Wallenstein Nicolau , Mialle Pierrick , Hereil Philippe
Published: March 2020

With the advent of civil aviation and growth in air traffic, the problem of volcanic ash encounter has become an issue of importance as a prompt response to volcanic eruptions is required to mitigate the impact of the volcanic hazard on aviation. Many volcanoes worldwide are poorly monitored, and most of the time notifications of volcanic eruptions are reported mainly based on satellite observations or visual observations. Among ground-based volcano monitoring techniques, infrasound is the only one capable of detecting explosive eruptions from distances of thousands of kilometers. On July 3 and August 28, 2019, two paroxysmal explosions occurred at Stromboli volcano. The events, that are similar in terms of energy and size to the peak explosive activity reported historically for the volcano, produced a significant emission of scoria, bombs and lapilli, that affected the whole island and fed an eruptive column that rose almost 5 km above the volcano. The collapse of the eruptive column also produced pyroclastic flows along the Sciara del Fuoco, a sector collapse on the northern flank of the volcano.

Being one of the best-monitored volcanoes of the world, the 2019 Stromboli paroxysmal explosions were observed in real-time and Civil Protection procedures started immediately. However, notification to the Toulouse Volcanic Ash Advisory Centre (VAAC) was not automated, and the VAA was issued only long after the event occurrence. The two explosions produced infrasound signals that were detected by several infrasound stations as far as Norway (IS37, 3380 km) and Azores islands (IS42, 3530 km). Despite of the latency due to the propagation time, infrasound-based notification arrays precedes the Volcanic Ash Advisories (VAAs) issued by Toulouse VACC. Following the same procedure applied for the Volcano Information System developed in the framework of the ARISE project, we show how infrasound array analysis could allow automatic, near-real-time identification of these eruptions with timely reliable source information. We highlight the need for an integration of the CTBT IMS infrasound network with local and regional infrasound arrays capable of providing a timely early warning to VAACs. This study opens new perspectives in volcano monitoring and could represent, in the future, an efficient tool in supporting VAACs activity.
Permafrost degradation monitoring by InSAR at different spatial resolution in Sanjiangyuan region, China
Authors: Ma Deying , Motagh Mahdi , Liu Guoxiang
Published: March 2020

Sanjiangyuan, as the Chinese ‘water tank’, is located in Qinghai province, China. It is the fountainhead of yellow river, Yangzi river and Lancang river. Therefore, it’s extraordinary valuable to the environment of China and Asia. The continuous permafrost spreads widely in this area. With the global warming process, the degradation of permafrost becomes faster and consequently changes the distribution of vegetation and hydrological cycle.

In this study, we use Persistent Scatterer InSAR (PSI) technique to efficiently detect the seasonal settlement around Elin lake and Zhaling lake, which are the main parts of Sanjiangyuan region. The subsidence was analyzed by processing 56 Sentinel-1 SAR images from 2015 to 2019 using SNAP and StaMPS. The results were then inverted to derive the corresponding active layer thickness over this region. Moreover, in order to investigate the detailed influence of degradation on infrastructures, we analyzed 3m resolution TerraSAR-X images in StripMap mode from May to October 2015 to get the heterogeneous subsidence along the Gonghe-Yushu road. Results indicate mean subsidence rates exceeding 4 cm/yr along the Gonghe-Yushu road .

 

 
Sharing EGU Conferences with Colleagues
Authors: Moran Alison
Published: March 2020

Science in Tomorrow’s Classroom: Sharing EGU Conferences with Colleagues

 

Alison Moran

Alden High School

13190 Park St

Alden, NY USA 14004

amoran@aldenschools.org

 

The European Geoscience Union was founded in 2002.  It began and continues to host conferences in 2004 and have graciously funded teachers from all over the world to attend by paying their conference fee, as well as giving a stipend to pay for some of the cost.  Their yearly conference attendance is approximately 15,000 scientists from all over the world.  While attending the conference one learns about new and continued trends seen in the field of Geoscience.  Every session had some take-away for teachers to use in their classroom or help with understanding of the curriculum.

 

I have attended two of these conferences have given me a wealth of information to use in my classroom.  I have taken activities from the conference and used them in my classroom; as well as passed this information along to my fellow colleagues.  During department meetings or superintendent conference days I would use this time to collaborate with colleagues and share activities.  I have incorporated many of the activities in my curriculum with positive feedback.  We as teachers need to collaborate with the science world to help our students achieve

 

The benefit of this is seen by the student’s ability to teach each other as well as the motivation to do more active learning.  I have seen better grades with using these activities with my students. 
Eemian environmental changes recorded in the north located lakes (N Poland and Germany) - subfossil Cladocera data
Authors: Niska Monika , Hrynowiecka Anna , Mirosław-Grabowska Joanna , Borner Andreas , Sokołowski Robert
Published: March 2020

In the current study the result of subfossil Cladocera analysis of the lake sediments from tree sites: Hinterste Mühle (H-M) (NE Germany), Rzecino (NW Poland) and Łęczyce (N Poland) of the Eemian Interglacial and the inferred environmental alterations are presented. The aim of the study was to reconstruct and compare the development of Eemian lakes located within the north of Poland and Germany as determined on the basis of the changes in subfossil Cladocera composition in the context of local conditions, climate change and natural evolutionary processes.

The studied reservoirs, fully developed during the Eemian Interglacial, were formed at the end of Late Saalian (MIS 6) and Early Eemian. The Hinterste Mühle profile is located in Mecklenburg-Western Pomerania. The site lies in the southeastern edge of the gravel pit, at about 48 m a.s.l. The Rzecino paleolake is located in the West Pomerania Lakeland (NW Poland), at an elevation of 104.5 m a.s.l. The Łęczyce palaeolake is located in northern Poland, on the northern slope of the Łeba river valley.

The subfossil Cladocera fauna from the H-M palaeolake is represented by 14 species belonging to three families. Three of them belong to a benthic group inhabiting mainly the bottom sediments, one to the open water zone, while the remaining species the dominant group occur among aquatic plants. Such a species composition marks a shallow water body or the littoral, macrophyte zone of a deeper lake. The Cladoceran fauna of deposits from the Rzecino paleolake are represented by 22 species that belong to four families. The majority of the remains consist of Chydoridae and Bosminidae. In the deposits, the ephippial eggs of the Daphnia longispina group, Ceriodaphnia spp., Chydorus spp., and Bosmina spp. are also identified. The subfossil cladoceran fauna of sediments in the Łęczyce profile is represented by 18 species that belong to four families. Most of the remains belong to the family of Chydoridae (13). Such species composition points to a deeper reservoir with a developed littoral zone with macrophytes.

Summing up, a similar pattern was observed in the research paleolakes related to the beginning of the existing of the lakes, their full development and ending time, different from the paleolakes found in the south, related to the location and more intense contact with cool air masses from Northern Europe.
Does the application of multiple hydrological models improve seasonal streamflow forecasting skill?
Authors: Klein Bastian , Pechlivanidis Ilias , Arnal Louise , Crochemore Louise , Meissner Dennis , Frielingsdorf Barbara
Published: March 2020

Many sectors, such as hydropower, agriculture, water supply and waterway transport, need information about the possible evolution of meteorological and hydrological conditions in the next weeks and months to optimize their decision processes on a long term. With increasing availability of meteorological seasonal forecasts, hydrological seasonal forecasting systems have been developed all over the world in the last years. Many of them are running in operational mode. On European scale the European Flood Awareness System EFAS and SMHI are operationally providing seasonal streamflow forecasts. In the context of the EU-Horizon2020 project IMPREX additionally a national scale forecasting system for German waterways operated by BfG was available for the analysis of seasonal forecasts from multiple hydrological models.

Statistical post processing tools could be used to estimate the predictive uncertainty of the forecasted variable from deterministic / ensemble forecasts of a single / multi-model forecasting system. Raw forecasts shouldn’t be used directly by users without statistical post-processing because of various biases. To assess the added potential benefit of the application of a hydrological multi-model ensemble, the forecasting systems from EFAS, SMHI and BfG were forced by re-forecasts of the ECMWF’s Seasonal Forecast System 4 and the resulting seasonal streamflow forecasts have been verified for 24 gauges across Central Europe. Additionally two statistical forecasting methods - Ensemble Model Output Statistics EMOS and Bayesian Model Averaging BMA - have been applied to post-process the forecasts.

Overall, seasonal flow forecast skill is limited in Central Europe before and after post-processing with a current predictability of 1-2 months. The results of the multi-model analysis indicate that post-processing of raw forecasts is necessary when observations are used as reference. Post-processing improves forecast skill significantly for all gauges, lead times and seasons. The multi-model combination of all models showed the highest skill compared to the skill of the raw forecasts and the skill of the post-processed results of the individual models, i.e. the application of several hydrological models for the same region improves skill, due to the different model strengths.
A global attribution study on historical heat-related mortality impacts attributed to climate change.
Authors: Vicedo Cabrera Ana Maria , Sera Francesco , Schneider dos Santos Rochelle , Tobias Aurelio , Astrom Christopher , Guo Yuming , Honda Yasushi , Delucca Anna , Hondula David , Ibarreta Dolores , Huber Veronika , Gasparrini Antonio
Published: March 2020

On behalf of the Multi-Country Multi-City Collaborative (MCC) Research Network.

Background & Aim: Climate change is considered the most important environmental threat to human health. Substantial mortality and morbidity burden have been directly or indirectly attributed to climate-sensitive environmental stressors. However, limited quantitative evidence exists on how much of this burden can be attributed to man-made influences on climate. In this large health attribution study, we aimed at quantifying the proportion of excess heat-related mortality attributed to anthropogenic climate change in recent decades across 626 locations across 41 countries in various regions of the world included in MCC database.

Methods: We first estimated the location-specific heat-mortality associations through two-stage time-series analyses with quasi-Poisson regression with distributed lag non-linear models and multivariate multilevel meta-regression using observed data. We then quantified the heat-related excess mortality in each location using daily modelled series derived from historical (factual) and preindustrial control (counterfactual) simulations from 5 general circulation models (ISIMIP2b database) in the period between 1991 and 2019. We finally computed the proportion of heat-related excess mortality attributable to anthropogenic influences as the difference between the two scenarios, with associated measures of uncertainty.

Results: We found a steep increase in level of warming, expressed as the difference in annual average temperature between scenarios, with an average increase of 1.0°C (from 0.7°C  to 1.2°C) across the 626 locations between 1991 and 2019. Overall excess heat-mortality fractions of 1.92% [95% confidence interval: 0.41, 3.25] and 1.28% [0.20, 2.50] were estimated under the factual and counterfactual scenarios, respectively, with an overall difference of 0.76% [0.25,1.74]. This translates to 33% of historical heat-excess mortality that can be attributed to anthropogenic climate change. Larger proportions were found in North America (46%), Central America (47%), South America (43%), South Africa (48%), Middle-East Asia (61%), South East-Asia (50%) and Australia (42%), although highly imprecise in most of cases.

Conclusions: Our findings suggest that current warming driven by anthropogenic influences is already responsible for a considerable proportion of the heat-related mortality burden. These results stress the importance of strengthening current mitigation strategies to reduce further warming of the planet and related health impacts.
Effect of Drought and Recovery on Grazing Animal, Microbial, and Fungal Response in a Diverse Multi-Crop Rotation
Authors: Landblom Douglas , Senturklu Songul
Published: March 2020

Beef cattle grazing, soil microbial respiration, and Rhizobia spp. populations serve important roles in soil nutrient cycling and during periods of drought, when abnormal precipitation declines, forage production for animal grazing and performance are negatively impacted. Soil nutrient availability is essential for adequate crop production and extended drought reduces soil microbial activity and therefore nutrient cycling. During the 2017 growing season between April and October in the northern Great Plains region of the USA, effective precipitation for crop production and animal grazing was severely reduced due an exceptional drought as classified by the US Drought Monitor. At the NDSU – Dickinson Research Extension Center, Dickinson, North Dakota, USA, a long-term integrated system that includes yearling steer grazing within a diverse multi-crop rotation (spring wheat, cover crop, corn, pea-barley intercrop, and sunflower). Within the rotation of cash and forage crops, beef cattle graze the pea-barley, corn, and cover crop (13-specie) within the rotation and is being utilized to monitor the effects of animal, microbial and fungal activity over time and space in the crop and animal production system. Nitrogen fertilizer has been replaced in the system by soil microbial and fungal activity (Potential Mineralizable Nitrogen: 8.4 mg N/kg) such that for each 1% increase in SOM there is a corresponding increase of 18.8 kg of potential nitrogen mineralized per ha. Animal grazing days are severely reduced when precipitation is inadequate for soil microbial respiration to occur. What is even more concerning, when relying on microbial activity to supply plant nutrients, is recovery time for microbial activity to fully recover from exceptional drought as was the case in this research project. Compared to the 2016 crop production year that preceded the 2017 drought, cover crop (13-specie), pea-barley, and corn yields were reduced 86, 33, and 64% during the 2017 drought. This decline in crop production reduced the number of days of grazing by an average 50% and average daily gains were also reduced. Steer average daily gains were 1.05 0.95, and 0.83 kg/steer/day in 2017 when grazing pea-barley, corn, and cover crop, respectively. For this research that relies on soil derived plant nutrients soil analysis for microbial and Rhizobia spp. biomass began recovery in 2018 and continued into 2019 as evidenced by large percentage increases in organism biomass; however, complete production recovery did not occur by the end of the 2019 grazing season in which days of grazing were reduced compared to the 2016 grazing season. Biological animal, crop, microbial, fungal, and nutrient replacement recovery will be presented in the poster.
How Coherent are Flux Variations in the Outer Van Allen Radiation Belt?
Authors: Walton Samuel , Forsyth Colin , Rae Iain Jonathan , Watt Clare , Horne Richard , Thompson Rhys , Rodger Craig , Clilverd Mark , Walach Maria
Published: March 2020

The electron population inside Earth’s outer radiation belt is highly variable and typically linked to geomagnetic activity such as storms and substorms. These variations can differ with radial distance, such that the fluxes at the outer boundary are different from those in the heart of the belt. Using data from the Proton Electron Telescope (PET) on board NASA’s Solar Anomalous Magnetospheric Particle Explorer (SAMPEX), we have examined the correlation between electron fluxes at all L's within the radiation belts for a range of geomagnetic conditions, as well as longer-term averages. Our analysis shows that fluxes at L≈2-4 and L≈4-10 are well correlated within these regions, with coefficients in excess of 80%, however, the correlation between these two regions is low. These correlations vary between storm-times and quiet-times. We examine whether, and to what extent this correlation is related to the level of enhancement of the outer radiation belt during geomagnetic storms, and whether the plasmapause plays any role defining the different regions of correlated flux.
Radar-based rainfall nowcasting for flash flood hazard assessment: recent results at regional and Continental scales
Authors: Berenguer Marc , Park Shinju , Sempere-Torres Daniel
Published: March 2020

Radar rainfall estimates and nowcasts have been used in Catalonia (NE Spain) for real-time flash flood hazard nowcasting based on the basin-aggregated rainfall for several years. This approach has been further developed within the European Projects ERICHA (www.ericha.eu) and ANYWHERE (www.anywhere-h2020.eu), where it has been demonstrated to monitor flash floods in real time in several locations and at different spatial scales (from regional to Continental coverage).

The work summarizes the main results of the recent projects, analysing the performance of the flash flood nowcasting system. The results obtained on recent events  show the main advantages and some of the limitations of the system.
Sedimentary DNA analyses decipher past and present aquatic plant diversity in Siberian and Tibetan lakes
Authors: Stoof-Leichsenring Kathleen R. , Liu Sisi , Jia Weihan , Epp Laura S. , Li Kai , Pestryakova Luidmila A. , Herzschuh Ulrike
Published: March 2020

In recent decades Arctic and Alpine terrestrial ecosystems experienced an increase in aquatic plant biomass due to global warming, which motivates the investigation of aquatic plant diversity in High Arctic and Alpine regions, whereof so far only sparse data exist. Aquatic plants are important primary producers, food resource and supply habitat structure and thus have been widely used to infer the ecological status of modern lakes. Identification of past aquatic plants using macrofossil records only partly reflects the past community structure due to differences in spatial distribution, preservation and seed abundance of taxa. Thus, in our study we applied sedimentary DNA analyses to detect aquatic plant diversity in modern surface samples of over 200 lakes from various localities across Northern, Eastern and Central Siberia and the Tibetan plateau and selected lake core samples (covering Holocene timescales) from these regions. We applied metabarcoding of the trnL marker and used Illumina technology for NGS amplicon sequencing of PCR products and performed OBITools pipeline for bioinformatic analyses and taxonomic assignment. Firstly, our study aims to evaluate if the trnL marker typically used for detecting terrestrial plant diversity can deliver valuable information on the composition of aquatic plants. Secondly, we will use ordination analyses to test which environmental variables (e.g. lake water depth, pH and conductivity) shape the diversity of genetically detected aquatic plants. Thirdly, we will analyze past genetic aquatic plant diversity from Holocene lake cores and compare it with the modern genetic data set to reconstruct putative drivers of past diversity changes. So far, we identified free-floating (Nymphoides, Ceratophyllum), submerged (Potamogeton sp.), wetland taxa (Caltha, Carex, Juncus) and bryophytes (Sphagnum) in modern and past genetic data sets. Further statistical analyses are pending and will be finalized and presented at EGU.
ITCZ-MIP: Understanding ITCZ width and its impacts on climate and circulation
Authors: Pendergrass Angeline , Watt-Meyer Oliver , Byrne Michael , Maher Penelope , Webb Mark , Schiro Kathleen , Su Hui
Published: March 2020

The intertropical convergence zone (ITCZ) is a band of intense rainfall near the equator that dominates tropical climate. Recent work has demonstrated that most climate models predict a narrowing of the ITCZ under global warming and this narrowing may act as a control on global precipitation (Byrne et al., 2018). Observations suggest that a narrowing of the ITCZ has already occurred (Wodzicki and Rapp, 2016). However, a firm theoretical understanding of what sets ITCZ width is still lacking and an understanding of how ITCZ width influences circulation and climate elsewhere is only beginning to be developed (e.g. Watt-Meyer and Frierson, 2019). Theoretical advances to date have been tested in an idealized gray-radiation model and across comprehensive coupled atmosphere-ocean models. We have begun an effort to systematically test theories of ITCZ width at an intermediate level of complexity: in aquaplanets with full radiation schemes but no seasonal cycle. Our approach is to use a slab ocean boundary condition to ensure energy conservation but at the same time constrain global mean surface temperatures to be similar across a small set of models. By imposing idealized q-flux profiles of heating in the deep tropics and cooling elsewhere, we vary ITCZ width. We also perform instantaneous CO2 quadrupling experiments to test the response to greenhouse gas forcing. Results from the protocol development and proof of concept phase of the effort, including simulations from three climate models, show changes in ITCZ width of up to 40% that are roughly linear in forcing. In these experiments, ITCZ width has substantial effects on global climate and circulation, including the strength of the ITCZ, global-mean temperature, and the Hadley cell. 
Implementation of an Impact-based Forecast System in Barbados
Authors: Kucera Paul
Published: March 2020

An operational Impact-based Forecast System (IBFS) has been established in Barbados through a series of implementation workshops, training sessions, and decision support application development.  UCAR/COMET collaborated with local partners and stakeholders including the Barbados Meteorological Service (BMS), Barbados Department of Emergency Management, (DEM), and the Caribbean Institute of Meteorology and Hydrology (CIMH) to develop the IBFS.  The project has been implemented in phases over a two-year period.  The phases include identifying the hazards, impacts, risks through stakeholder workshops; developing new standard operating procedures; adapting software tools to include the IBFS framework; training of stakeholders; testing and evaluation of system using case studies; and development of documentation for public outreach.  The system is expected to be operational in June 2020.  The presentation will provide an overview of the Barbados IBFS and lessons learned during the project.
Seasonal forecast of water resources over the Euro-Mediterranean region
Authors: Dayon Gildas , Besson François , Soubeyroux Jean-Michel , Viel Chrisitian , Marson Paola
Published: March 2020

In the framework of the MEDSCOPE project, a forecasting chain is developed at Météo-France for hydrological long term predictions over the Euro-Mediterranean region, from one month up to seven months. This new prototype is based on the Météo-France System 6 global seasonal forecast system. Atmospheric forecasts are interpolated to 5.5 km and corrected by the statistical method ADAMONT using the UERRA regional atmospheric reanalysis as reference. These high resolution forecasts drive the physically-based model SURFEX coupled to CTRIP providing seasonal forecasts of surface variables : river discharges, soil wetness indices, snow water equivalent.

A forecast using the climatology (ESP approach) has been produced on the period 1993-2016. It is use to explore the sources of predictability in the different watersheds (Ebro, Po, Rhône). Predictability is mostly coming from the snow pack built during the winter and the soil moisture evolution in spring and summer. A hindcast on the period 1993-2016 is produced to assess the added value of the seasonal forecast compared to the climatology for the end-users in agriculture and energy.
Hemispheric asymmetry of the ionospheric variation during major sudden stratospheric warming events
Authors: Zhang Donghe , Liu Jing
Published: March 2020

The hemispheric asymmetry of the ionospheric variation in the American sector (45°N~45°S, MLAT; 80°~60°W) is studied with total electron content (TEC) data during major sudden stratospheric warming events. The amplitude (AM2) and relative strength (RSM2) of the semi-diurnal lunar tidal component (M2) of TEC are analyzed. RSM2 is the ratio between the energy of M2 and the energy of all the studied tidal components. The magnitudes of AM2 and RSM2 exhibit clear hemispheric and latitudinal variations. The AM2 in the north of the magnetic equator tends to occur at lower magnetic latitudes than the AM2 in the south of the magnetic equator. The RSM2 exhibits similar features as the AM2 but the difference is more distinct. We suggest that such hemispheric asymmetry of M2 parameters is related to the hemispheric asymmetry of the EIA and the latitudinal variation of the amplitude of the solar tidal components in winter.
Root traits as key proxies to unravel plant and ecosystem functioning: entities, trait selection and outlook
Authors: Rewald Boris , Freschet Grégoire T. , Roumet Catherine , Stokes Alexia , Weemstra Monique , Bardgett Richard D. , Bengough A. Glyn , Comas Louise H. , De Deyn Gerlinde B. , Johnson David , Klimešová Jitka , Lukac Martin , McCormack M. Luke , Meier Ina C. , Pagès Loïc , Poorter Hendrik , Prieto Ivan , Wurzburger Nina , Zadworny Marcin
Published: March 2020

Root systems show a tremendous diversity both between and within species, suggesting a large variability in plant functioning and effects on ecosystem properties and processes. In recent decades, developments in many areas of root research have brought considerable advances in our understanding of root traits and their contribution to plant and ecosystem functioning. However, despite major progress, a comprehensive overview—bridging research fields—is lacking. Furthermore, considerable uncertainties exist in the identification of root entities, and the selection and standardized measurement of traits. Here, we provide a comprehensive overview on root entities, exemplify recent advances in our understanding of both theoretical and demonstrated relationships between root traits and plant or ecosystem functioning, discuss trait-trait relationships and hierarchies among traits, and critically assess current strengths and gaps in our knowledge.
From perched high elevation surfaces to sediment entering the foreland: the dynamics of erosion, deformation and landscape evolution in the Argentine Precordillera
Authors: Hoke Gregory , Val Pedro , Ruetenik Gregory , Moucha Robert
Published: March 2020

The geomorphic processes that control temporal and spatial patterns of erosion, sediment storage and evacuation in an active mountain range (source) have a direct impact on how the signal of tectonics and climate, are recorded in the adjacent sedimentary basins (sinks). Stream power based numerical models of landscape evolution predict strong time lags between rock uplift and waves of erosion in the foreland, but this is difficult to test without proper resolution between source and sink signals..  Confirmation of model results is typically gleaned through observations that are either snapshots of processes in modern systems, or inversion of the stratigraphic record to decipher what occurred in the uplands. While cosmogenic nuclide derived, catchment wide erosion rates in the modern rivers provide a snapshot of processes happening in the last thousands of years, thermochronmeters average over the ≥ millions of years it takes a rock to ascend from the closure isotherm to the Earth’s surface,making it difficult, if not impossible to capture a minimally time averaged signal of the geomorphic system in the stratigraphic record. Paleoerosion rates from the residual cosmogenic nuclide concentration of buried sediments offer a means to bridge the gap in resolution. 

 

This study combines numerical modeling and cosmogenic nuclide paleoerosion rates in the Argentine Precordillera to build a rich picture of how this foreland basin system, from the hinterland through the foreland basin evolves in time and space. Our modeling shows that the dynamics of wedge-top basin formation behind a rising, and then subsequently inactive range have profound and systematic effects on the geomorphic signals both upstream and downstream of the wedge-top basin. Downstream, it is clear that there are strong, million year time lags in the uplift-triggered erosive pulse and spatial controls on where the sediment delivered to the foreland is sourced. Upstream, aggradation in the wedge top leads to the development of a wave of low erosion into the hinterland that results in the creation of perched surfaces coeval to erosive pulses downstream. In the Argentine Precordillera at 30°S an 8 Ma record of paleoerosion rates from the wedge top and foreland basin deposits along with detrital zircons provenance in the foreland largely verifies the predictions of the numerical modeling. Similarly, upstream of the wedge-top basin, there are concordant knickpoints and large, broad planation surfaces perched some 1500 m above the floor of wedge top as predicted by the low erosion wave pulse. Our combination of numerical modeling and paleoerosion rates capture the dynamic evolution of mountain range at million to thousand year timescales. 
Cropland expansion and productivity reduction in Malawi monitored by using Satellite data
Authors: Li Chengxiu , Dash Jadu
Published: March 2020

With rising demand for food in Sub-Saharan Africa (SSA), cropland expansion represents the main strategy to boost agricultural production. However, cropland expansion is not a sustainable form of agricultural development as there is limited arable land and increasing soil degradation in SSA. Cropland expansion needs to be monitored in order to focus intervention and propose alternatives. In this study, we monitor agriculture expansion over the past decades across Malawi using Landsat satellite data and explore factors that can explain expansion using Malawi integrated household survey data. The preliminary results showed that cropland expansion has widely occurred across the country, and the newly expanded croplands have higher productivity compared to the croplands with long cultivation history. We also found that estate agricultural land contributes to 40% of the expanded area and the level of irrigation is negatively correlated to expansion, being the dominant factors that are associated with expansion in Malawi. The results will further help to offer localized information for policy making and to develop strategies for conserving land.

 
A climatology of dust episodes in the broader Mediterranean Basin using satellite MODIS C6.1 and OMI OMAERUV data
Authors: Hatzianastassiou Nikos , Gavrouzou Maria , Gkikas Antonis , Mihalopoulos Nikos
Published: March 2020

Aerosols, due to their interaction primary with the shortwave, but also with the longwave radiation, constitute a significant climate component, and at the same time an important, but still uncertain, factor of the contemporary climatic change. Apart from radiation, aerosols also interact with clouds, acting as Cloud Condensation Nuclei (CCN) and/or Ice Nuclei (IN), modifying the cloud optical and physical properties like cloud albedo, extent, lifetime or precipitation producing ability. Hence, it is also expected that high loads of specific aerosol types, such as desert dust, can induce even stronger effects on the above mentioned cloud properties.

More specifically, dust aerosols, which are inserted in the atmosphere mainly from the great world deserts, represent the major global aerosol component. These aerosols can remain suspended in the air and travel for several days, reaching areas far away from their sources. The Mediterranean Basin (MB), which is one of the most responsive regions to climate change, due to its location (nearby the Sahara desert in North Africa and the deserts of Middle East), is frequently affected from massive and extended dust transport. Because of the potentially significant role of these dust episodes, and their seasonal and inter-annual variability, they are worth to be studied and monitored through time.

In the present study, a modified version of a satellite algorithm, which is fully described by Gavrouzou et al. in another study of this conference, is used for the determination of strong and extreme dust episodes in the Mediterranean Basin over the period 2005-2018. The algorithm, using MODIS C6.1 spectral Aerosol Optical Depth (AOD) and OMI OMAERUV Aerosol Index (AI) as input data, ran on a daily and an 1°x1° pixel level basis and determined the occurrence and intensity of dust episodes whenever the AI is greater than 1 and the Angstrom Exponent (AE), which is calculated from spectral AOD data, is lower than 0.4. Any day is characterized as an episodic one when the dust optical depth (DOD) exceeds a computed threshold value (mean value plus two or four standard deviations for strong and extreme episodes, respectively) on at least 30 pixels of the study area. According to the algorithm results, 148 dust episode days (104 strong and 44 extreme) are found during the 2005-2018 period in the Mediterranean Basin. Most of the episodes occur in July (27 strong- and 3 extreme-episode days) and April (25 strong- and 6 extreme-episode days) while dust episodes are not detected at all in November and December. It is also found that in April, March and May take place the highest number of extreme MB episodes (23 out of the total 44 ones).
Effects of prescribed burning on soil fertility and carbon dynamics in pre-littoral Mediterranean mountain pastures
Authors: Manjón-Cabeza José , Ibáñez Mercedes , Rodríguez Antonio , Broncano Maria Josep , Plaixats Josepa , Sebastià Maria Teresa
Published: March 2020

 Prescribed burning is a management tool used in the last years to prevent the invasion of woody vegetation in pastureland, decreasing the risk of extensive wildfires in vulnerable areas. Nevertheless, the effect of this practice in the soil is not yet fully understood, and more information is needed to ameliorate management practices. In order to understand how prescribed fire affect soil fertility, and the carbon (C) and nitrogen (N) cycles in pastures invaded by shrubs in Mediterranean areas, we carried out an experiment in Montseny, an acidic pre-littoral mountain range northern Barcelona (NE Iberian Peninsula). This area has experienced a decrease in traditional sheep stocks and therefore pastures endure strong shrub encroachment. We wanted to know: 1) what are the effects of prescribed burning on soil fertility in acidic Mediterranean pastures? and 2) are there legacy effects of the previous vegetation patches on the soil C and N cycles after prescribed burning? To answer those questions, we sampled soils before and after prescribed burning of a pasture heavily invaded by shrubs. Soils were sampled under six canopy types: Erica scoparia-dominated patches, Calluna vulgaris-dominated patches, Cytisus scoparius-dominated patches, Pteridium aquilinum-dominated patches and Cladonia-dominated biological crusts. The exact soil sampling point was recorded by a highly precise GPS, and each point resampled few days and six months after burning. As expected, soil fertility parameters varied with burning, including losses in soil phosphorus and nitrogen. In addition, several soil C and N parameters responded to the previous vegetation patches, including shifts in soil C and N concentration.