bluuebunny/crossref_metadata_2025 huggingface dataset:
Representation of model error in convective scale data assimilation
Authors: Janjic Tijana , Zeng Yuefei , de Lozar Alberto , Ruckstuhl Yvonne , Blahak Ulrich , Seifert Axel
Published: March 2020

Model error is one of major contributors to forecast uncertainty. In addition, statistical representations of possible model errors substantially affect the data assimilation results. We investigate variety of methods of taking into account model error in ensemble based convective scale data assimilation. This is done using the operational convection-permitting COSMO model and data assimilation system KENDA of German weather service, for a two-week convective period in May 2016 over Germany. Conventional and radar reflectivity observations are assimilated hourly by the LETKF. For example, to take into account the model error due to unresolved scales and processes, we use the additive noise with samples coming from the difference between high-resolution model run and low-resolution experiment. We compare this technique for assimilation of radar reflectivity data to other methods such as RTPS, warm bubble initialization, stochastic boundary layer perturbation and estimation of parameters. To further improve on additive noise technique, which consists of perturbing each ensemble member with a sample from a given distribution, we propose a more flexible approach in which the model error samples are treated as additional synthetic ensemble members that are used in the update step of data assimilation but are not forecasted. In this way, the rank of the model error covariance matrix can be chosen independently of the ensemble. This altered additive noise method is analyzed as well.
IcePicks: a collaborative database of Greenland outlet glacier termini
Authors: Goliber Sophie , Black Taryn , Catania Ginny
Published: March 2020

Marine-terminating outlet glacier terminus change mapped from satellite and aerial imagery in Greenland is used extensively in understanding how outlet glaciers adjust to climatic changes over a range of time scales. Numerous studies have digitized termini manually, but this process is labor-intensive and may lead to duplication of efforts. Additionally, these studies use different methods to pick the front (e.g. centerline pick, whole delineation, box method), which makes them difficult to compare. At the same time, machine learning techniques are rapidly making progress in their ability to accurately automate the extraction of glacier termini, with promising developments across a number of satellite sensors. However, limitations still exist: in particular, further high-quality manually-digitized training data are needed to make robust automatic picks. Here we present efforts to produce a database of manually digitized terminus picks and an intercomparison of picking techniques to determine errors and best practices for future efforts in digitization. These data will be cleaned, associated with appropriate metadata, and compiled so they can be easily accessed by scientists. Ultimately, these data will be used to create training data for further automatic picking efforts. We hope to solicit further collaboration with members of EGU and encourage those interested to email the authors.
Iceland-Faroe Ridge overflow dynamics, 55-6 ka BP
Authors: Mirzaloo Maryam , Nürnberg Dirk , Kienast Markus , van der Lubbe Jeroen
Published: March 2020

The understanding of the past changes in this critical area of oceanic circulation will be beneficial to predict future climate conditions and their related socio-economic impacts. Sediment cores recovered from the western flank of the Iceland-Faroe Ridge (IFR; P457-905 and -909) provide unique archives to reconstruct changes in the Iceland-Scotland overflow water (ISOW), an important component of the Atlantic Meridional Overturning Circulation (AMOC) over the last 55-6 ka BP. We provide high-resolution records of lithogenic grain-size and XRF bulk chemistry on millennial timescales. The age models of both cores have been constrained by radiocarbon datings of planktonic foraminifera and distinct tephra layers, which include the well-known Faroe-Marine-Ash-Zones (FMAZ) II and III. Both grain-size and XRF bulk chemistry (Zr/Rb and Ti/K) reveal prominent Dansgaard-Oeschger sedimentary cycles, which reflect considerable changes in near-bottom current strength and sediment transport/deposition. The transition between cold Greenland Stadials (GSs) and warm Greenland Interstadials (GIs) occur in typical, recurring sedimentation patterns. The GIs are characterized by relatively strong bottom currents and the transport/deposition of basaltic (Ti-rich) silts from local volcanic sources resembling the modern ocean circulation pattern. In contrast, fine grained felsic (K-rich) sediments were deposited during GSs, when the ISOW was weak. In particular, the Heinrich (like) Stadials HS1 and HS2 stand out as intervals of very fine felsic sediment deposition and hence, slackened bottom currents. The bottom currents appear to progressively strengthen throughout the GIs, and sharply decline towards the GSs. This pattern contrasts with records from north of the IFR, which might be explained by a diminishing contribution of the flow cascading over the IFR. Together, these new records show strong changes in bottom current dynamics related to the Iceland-Scotland overflow, which has a strong influence on the past and modern climate of the North Atlantic Region. However, climate change is an interdisciplinary field of research. HOSST-TOSST transatlantic interdisciplinary research program provides the unique opportunity for constructive communication and collaboration among scientists with different skills filling knowledge gaps and bridging the earth sciences with social and economic disciplines. Such interdisciplinary programs at early stages in an academic career is necessary to move and encourage the new generation of the scientific community toward a tradition of broad‐scale interactions.

 

 

 

 

 

 

 

 

 
Impact of Groundwater Pumping on Flood Potential (FP) in Indian Sub-continental River Basins
Authors: Shah Deep , Mishra Vimal
Published: March 2020

Rapid groundwater depletion is one of the most vital issues related to food and water security in India. However, the crucial role of groundwater pumping and associated policy measures on Flood Potential (FP) in Indian subcontinental river basins remains unexplored. In this study, we examine the impact of groundwater pumping on FP in the Indian subcontinental river basins, having different climatic characteristics. We used Terrestrial Water Storage (TWS) from Gravity recovery climate experiment (GRACE) satellites and precipitation data from the India Meteorological Department (IMD) and Tropical Rainfall Measuring Mission (TRMM) to estimate FP. We estimated the trends of TWS and FP using the nonparametric Mann–Kendall (M-K) method and Sen’s slope method was used to calculate trend magnitudes. We evaluated the results of FP with observed monthly discharge. Moreover, we find a decline in FP in river basins having rapid groundwater depletion. However, no significant change in FP was found for basins where strong policy measures have taken against groundwater pumping.
The IDS Contribution to the ITRF2020: Preliminary results
Authors: Moreaux Guilhem , Lemoine Frank , Capdeville Hugues , Štěpánek Petr , Ferrage Pascale
Published: March 2020

To provide its contribution to the next realization of the International Terrestrial Reference Frame (ITRF2020), the International DORIS Service (IDS) plans to complete the re-analysis of the DORIS data from 1993.0 to 2021.0 by early 2021. In preparation for the development of its contribution, the IDS completed several pilot studies for a better modelling of the solar radiation pressure, to mitigate the effect of the South Atlantic Anomaly on the DORIS receivers, to improve the stability of the DORIS scale. The complete re-analysis is divided in several parts depending on the time evolution of the DORIS constellation and on modelling issues.

IDS Analysis Center contributions for first time period, which corresponds to the observations from the DORIS satellites with the first generation of the DORIS receivers: 1993.0-2002.3 (start of Envisat – first DORIS 2G receiver), are expected by the end of the first quarter of 2020.

After presentation of the status of the main guidelines of the DORIS contribution to the ITRF2020, we will analyze the first time period of the DORIS contribution to ITRF2020 in terms of (1) geocenter and scale solutions; (2) station positions and week-to-week repeatability; (3) EOPs. In addition, we will compare this new DORIS solution with the IDS contribution to ITRF2014. Then, we will present updated results on the latest IDS pilot studies.
Predicting the propagation and interaction of frontal accretionary thrust faults with work optimization
Authors: Cooke Michele , McBeck Jess , Fattaruso Laura
Published: March 2020

This study assesses the ability of work optimization to predict the spatial and temporal initiation of faults. We focus on the growth of flaws that develop into thrust faults at the toe of accretionary prisms because observations from physical laboratory accretion experiments provide rich data with which to validate the models, and the processes of accretionary thrust fault initiation remain unclear. In order to model these systems, we apply new implementations to the fault growth code GROW that improve its prediction of fault interaction using work optimization, including: 1) CPU parallelization, 2) a new growth algorithm that propagates only the most efficient fault in each growth increment, the single run mode, and 3) a new growth algorithm that only considers fault propagation from fault tips that host high sums of modes I and II stress intensity factors, KG, the limiting mode. The single and limiting mode produce the geometries that best match the observed geometries, rather than the previous algorithm that allows all the faults to propagate simultaneously, regardless of KG, the multiple and non-limiting mode. The single limiting models predict that frontal accretionary thrusts initiate at the midpack or shallower depths, consistent with findings of previous studies. The thrusts propagate upward, link with the surface, and then propagate downward and link with the detachment. The backthrust tends to propagate before the forethrust, and then influence the forethrust propagation. This temporal and spatial sequence of faulting arises from the lower compression, higher shear strain, higher Coulomb stress and higher strain energy density that develop near the wedge surface and the inflection of the wedge slope. The models reveal that the final slip distributions do not reliably indicate the initiation location of the faults, in contrast to the assumptions of previous analyses.
The 2019 eruptive phase of Stromboli volcano through multiparametric geophysical observations.
Authors: Orazi Massimo , Giudicepietro Flora , López Carmen , Macedonio Giovanni , Alparone Salvatore , Bianco Francesca , Calvari Sonia , De Cesare Walter , Delle Donne Dario , Di Lieto Bellina , Esposito Antonietta , Peluso Rosario , Privitera Eugenio , Romano Pierdomenico , Scarpato Giovanni , Tramelli Anna
Published: March 2020

In summer 2019, two paroxysmal explosions occurred in Stromboli. The first one occurred on July 3, when the Strombolian ordinary eruptive activity did not show a significant intensification. The explosion formed an eruptive column more than 3 km high. A pyroclastic flow ran down the “Sciara del Fuoco” slope causing a victim and some injuries. Moreover, the pyroclastic flow spread over the sea surface for about one kilometer. On August 28, a second paroxysmal explosion occurred, similar to the previous one. Also in this case the eruption formed an eruptive column of more than 3 km and a pyroclastic flow that expanded along the “Sciara del Fuoco” slope and traveled about 1 km on the sea surface. In the period between the two paroxysms, effusive activity occurred from the summit crater area. The eruptive phase of summer 2019, which began with the paroxysm of 3 July, was not preceded by significant changes in the routinely monitored parameters, such as the hourly frequency (daily average) of the VLP events (typical of Stromboli) and the amplitude of the seismic signal (RSAM). For this reason, we have analyzed the seismic and dilatometric data, which were recorded by the INGV geophysical network in the period November 2018 - September 2019, focusing our attention on other parameters that can give indications on the activity state of the volcano. In particular, we analyzed the data of the broadband seismic stations, equipped with the Guralp CMG40T sensors, and the data of one Sacks-Evertson borehole strainmeter. We defined the "VLP size", which takes into account the waveform of the VLP events, in terms of both amplitude and duration. We also applied time varying Fractal Dimension (FD) analysis to the seismograms of a seismic station close to the crater area and we analyzed the polarization of the same signal. We carried out the polarization analysis both without applying a filter and by filtering the seismic signal in the typical frequency bands of the Stromboli volcanic tremor (1-3 Hz) and of the VLPs (0.5-0.05 Hz). We found that the "VLP size", the FD and the polarization parameters showed significant changes about one month before the paroxysm of July 3. In the short term, we applied an appropriately tuned STA/LTA algorithm to the data of the borehole strainmeter, which is installed on the island at about 2km from the craters, and we obtained an automatic detection of the paroxysmal events 10 and 7.5 minutes before the explosion of July 3 and August 28, respectively.
Pathline Density Distributions in a Null‐Space Monte Carlo Approach to estimate Groundwater Pathways for a Major Water Supply System
Authors: Moeck Christian , Molson John , Schirmer Mario
Published: March 2020

A null‐space Monte‐Carlo (NSMC) approach was applied to assess uncertainty in the calibration of the hydraulic conductivity (K) field for a three‐dimensional groundwater flow model of a major water supply system in Switzerland. Different parameter realizations of the K field are generated by applying the pilot point methodology. Backward particle tracking (PT) was then applied to each calibrated model, and the resulting particles are interpreted as the spatial pathline density distribution of multiple sources. The adopted approach offers advantages over classical PT which does not provide a means for treating uncertainty originating from the incomplete description of the K field. Besides evaluating the effect of uncertainty in the K field on pathline distribution, the importance of the chosen boundary conditions for flow predictions is also investigated by applying a linear uncertainty approach.

Uncertainty in the K field is shown to strongly influence the spatial pathline distribution. Pathline spreading is particularly evident in locations where the information content of the head observations does not sufficiently constrain the estimated parameters. As demonstrated with the linear uncertainty analysis, however, the artificial recharge rates and the pumping well conditions can also significantly affect the model predictions. Explicitly accounting for uncertainty in the boundary conditions is therefore a necessity rather than a choice.

Despite the predictive uncertainty, the pumped drinking water at the study site is most likely dominated by artificially‐infiltrated groundwater originating from the local artificial infiltration canals and ponds. The results suggest that within the well field, the central pumping wells could be extracting regional groundwater, although the probability is relatively low. Nevertheless, a rigorous uncertainty assessment is still required since only a few realizations resulted in flow paths that support the field observations from tracer tests and on-site noble gas measurements to estimate groundwater mixing ratios.

We demonstrate that standard PT approaches without a Monte-Carlo approach will not represent the underlying subsurface uncertainty and will always underestimate well capture zones. While PT based on a single flow simulation can be used as an initial screening tool, model results and hence water resource management decisions should not be based on only one model realization; rather, an uncertainty analysis should be carried out to provide simulations within the range of all likely system states, including uncertainties in the hydraulic K distribution.
Heterogeneous cloud-supercomputing framework for daily seismic noise source inversion
Authors: Gokhberg Alexey , Ermert Laura , Igel Jonas , Fichtner Andreas
Published: March 2020

The study of ambient seismic noise sources and their time- and space-dependent distribution is becoming a crucial component of the real-time monitoring of various geosystems, including active fault zones and volcanoes, as well as geothermal and hydrocarbon reservoirs. In this context, we have previously implemented a combined cloud - HPC infrastructure for production of ambient source maps with high temporal resolution. It covers the entire European continent and the North Atlantic, and is based on seismic data provided by the ORFEUS infrastructure. The solution is based on the Application-as-a-Service concept and includes (1) acquisition of data from distributed ORFEUS data archives, (2) noise source mapping, (3) workflow management, and (4) front-end Web interface to end users.

We present the new results of this ongoing project conducted with support of the Swiss National Supercomputing Centre (CSCS). Our recent goal has been transitioning from mapping the seismic noise sources towards modeling them based on our new method for near real-time finite-frequency ambient seismic noise source inversion. To invert for the power spectral density of the noise source distribution of the secondary microseisms we efficiently forward model global cross-correlation wavefields for any noise distribution. Subsequently, a gradient-based iterative inversion method employing finite-frequency sensitivity kernels is implemented to reduce the misfit between synthetic and observed cross correlations.

During this research we encountered substantial challenges related to the large data volumes and high computational complexity of involved algorithms. We handle these problems by using the CSCS massively parallel heterogeneous supercomputer "Piz Daint". We also apply various specialized numeric techniques which include: (1) using precomputed Green's functions databases generated offline with Axisem and efficiently extracted with Instaseis package and (2) our previously developed high performance package for massive cross correlation of seismograms using GPU accelerators. Furthermore, due to the inherent restrictions of supercomputers, some crucial components of the processing pipeline including the data acquisition and workflow management are deployed on the OpenStack cloud environment. The resulting solution combines the specific advantages of the supercomputer and cloud platforms thus providing a viable distributed platform for the large-scale modeling of seismic noise sources.
Forecasting landslide at slope-scale: past achievements, present challenges and future perspectives
Authors: Intrieri Emanuele , Carlà Tommaso , Gigli Giovanni , Casagli Nicola
Published: March 2020

In general, the most reliable parameters to forecast the occurrence of a landslide are kinematics parameters, such as displacement, velocity and acceleration, since they represent the direct indicator of the stability conditions of a slope. Despite recent advancement in satellite interferometry, the highest temporal resolution, necessary to set up an effective early warning system, are still achievable from ground-based instrumentation.

Within this framework a few methods to forecast the time of failure of landslides at slope-scale have been developed in the last decades and, in many instances, they have been successfully used to prevent casualties and economic losses.

Common applications include public safety situations and open-pit mines, for which accurate warnings are crucial to protect workers and at the same time avoid unnecessary interruptions of the extraction activities.

In this work, a review of the most relevant kinematics-based forecasting methods is presented. Some examples are shown to illustrate the respective advantages, limitations and range of applicability of each method. Future challenges, trends and opportunities provided by technological innovations and scientific advances, also in related fields such as Material Science and Applied Mathematics, are also presented.
Large-scale laboratory experiments on tsunamis generated by submarine volcanic eruptions in a wave basin
Authors: Liu Yibin , Fritz Hermann M.
Published: March 2020

Among the wide spectrum of volcanic tsunamis, the most devastating events have been caused by extremely explosive eruptions, pyroclastic flows and debris avalanches of underwater or near surface volcanos. The 2015 “orange” alert at the Kick ‘em Jenny submarine volcano in the Caribbean Sea highlighted the challenges in characterizing the tsunami waves for a potential submarine volcanic eruption. The 2018 Anak Krakatau eruption and flank collapse generated tsunami resulted in a near water surface setting of the volcanic vents similar to these laboratory experiments and relevant for the remaining and future tsunami hazards.

Source and runup scenarios are physically modeled using generalized Froude similarity in the three dimensional NHERI tsunami wave basin at Oregon State University. A novel volcanic tsunami generator (VTG) was deployed to study submarine volcanic eruptions with varying initial submergence and kinematics. The VTG consists of a telescopic eruptive column with an outer diameter of 1.2 m. The top cap of the pressurized eruptive column is accelerated vertically by eight synchronized 80 mm diameter pneumatic pistons with a stroke of 0.3 m. More than 300 experimental runs have been performed which include around 120 combinations of velocities and water depths. The variable eruption velocities of the VTG can mimic a wide range of processes ranging from relatively slow mud volcanoes and rapid explosive eruptions. The gravitational collapse of the eruptive column represents the potential engulfment and caldera formation. Water surface elevations and onshore runup are recorded by an array of resistance wave gauges and runup gauges. The VTG displacement is measured with an internal linear potentiometer and above and underwater camera recordings. Water surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. The water surface spike from the concentric collision of wave crest is observed under a limited range of Froude numbers. The energy conversion rates from the volcanic eruption to the wave train are quantified for various scenarios. Predictive equations of wave and spike characteristics are obtained and compared with existing linear and non-linear theories. The measured volcanic eruption and tsunami data serve to validate and advance three-dimensional numerical volcanic tsunami prediction models.
The community consultation process leading to the compilation of the 23 Unsolved Problems in Hydrology (UPH)
Authors: Cudennec Christophe , Arheimer Berit , Blöschl Günter , Ramos Maria Helena , Toth Elena
Published: March 2020

This contribution summarizes the steps of, and experiences with, a wide consultation process, led by the International Association of Hydrological Sciences (IAHS) that resulted in a list of 23 major unsolved scientific problems (UPH) in hydrology.

Step 1) Launch of a YouTube video, outlining the purpose of the initiative and its vision.

Step 2) Discussion via a LinkedIn group leading to a total of about 200 contributions and responses.

Steps 3-4) Two ‘in-person’ meetings organised in April 2019 in Vienna: one (Step 3) at the EGU General Assembly (attended by about 60 scientists), in order to solicit additional questions, at the end of which about 260 candidate problems had been compiled; the second one (Step 4) at the Vienna Catchment Science Symposium (VCSS) at the Vienna University of Technology (attended by about 110 scientists), to sort, merge, split, reword and prioritise the proposed questions. Through an iteration of parallel sessions (repeated twice, mixing the participants) and a final plenary voting session, a list of 16 ‘gold‘ and 29 ‘silver‘ questions was identified.

Step 5) Synthesis carried out by a small working group, involving representatives and members of IAHS, IAH, EGU and AGU, to consolidate, interpret and synthesise the questions, as well as to address potential biases in their selection that might have arisen from the composition of the participants at the meetings. The working group also pooled the questions into seven themes for clarity and communication. As a result of the synthesis process, the working group finally listed a set of 23 questions, presented in a community paper with over 200 authors (Blöschl et al., 2019, https://doi.org/10.1080/02626667.2019.1620507).

The UPH initiative is a proof of concept that this kind of broad consultation process is actually feasible, and is well received by the hydrological scientific community. Thus, equally important as the final list, is the community-level learning process of such a consultation, involving a large number of hydrologists and the four main learned societies in the field.

Consultations such as this could and should be repeated in the future for the benefit of our discipline, since providing common research subjects will increase the coherence of the scientific process in hydrology and promote the co-building of scientific strategies and synergy towards accelerated progress in hydrological sciences and applications.

This PICO presentation gives a short overview of the consultation process and of each of the 23 questions, shares the experiences from the process and proposes some possible future steps.
It’s Our Future, Ask Us: Centring Children’s Voice In Geoscience Educational Research
Authors: Neenan Emer Emily , Roche Joseph
Published: March 2020

The world is facing a future of rising temperature, rising sea levels, and rising incidences of natural disasters. Key decisions in environmental, scientific, and educational policy taken now will determine what kind of world today’s schoolchildren will inherit when they come of age in an era of climate change. This paper reflects on the use of Children’s Research Advisory Groups (CRAGs) in geoscience educational research aimed at informing or influencing future policy. Building from the work of Lundy & McEvoy (2009) and Murphy et al. (2013), CRAGs are a method of including and centring children’s voice in geoscience educational research that will affect them. An ongoing mixed methods study of student engagement with and understanding of Earth Science in Irish secondary schools uses CRAGs to include the voices of school students. These CRAGs are convened in three representative schools in the study and comprise students representative in age and demographics of the participants of the study. The CRAGs are consulted at multiple stages, including before the pilot survey and after results are compiled, and their input guides key decisions within the project, including the language used in the survey, the format of the information provided to schools, and the conclusions drawn. This paper will discuss the benefits and challenges of incorporating children’s voices in research, particularly with regard to educational research and research aimed at impacting climate and environmental policies.
The School in the Park. A purpose for our future: 0 km water.
Authors: Paolessi Paola
Published: March 2020

IPSSEOA “via De Gasperi” is a hotel management high school specialized in reception and “enogastronomy” (food and wine). Over 750 students are divided into different sections according to specialization and study for five years. The school is located in Palombara Sabina, in the north east province of Rome, on the edge of a protected area of ​​regional interest, Parco Naturale Regionale dei Monti Lucretili. For several years the school has been carrying out environmental education programs oriented towards sustainability and the acquisition of good environmental habits by students and their families through targeted projects, workshops and excursions.

We believe that an educational institution that trains potential kitchen and hotel managers should have as one of its main purpose the care of people and environment. Therefore, the school year 2019-2020 project focuses on reducing plastic consumption by encouraging the use of public water, which comes from some springs, “Sorgenti Le Capore” in the territory of the Monti Lucretili Park. Students will personally test the goodness of tap water through excursions, workshops, direct observations and analysis of samples. Even the emotional side and the sense of belonging will be solicited, also thanks to the support of associations and entities present in the area. In particular, the "Terraemani" association and the APS (Acqua Pubblica Sabina) organization that manages the public aqueduct will be involved in the project. Then, students will have the opportunity to rationally choose which water to consume, public or bottled water. The challenge will therefore be to promote 0 km water.

Presentation type preference: Poster

 

 
Precipitation trends and ruptures effect on catchment hydrology and water resources availability for agricultural lands under climate change
Authors: Hrour Youness , Thomas Zahra , Fovet Ophélie , Rousseau-Gueutin Pauline , Pichelin Pascal , Sebari Karima
Published: March 2020

Water resources depletion under climate change is a major concern over the world. Mediterranean countries are deeply affected by changes in precipitation intensity, duration and frequency. Such changes lead to decrease in the averaged stream discharge and groundwater recharge consequently decreasing water resources availability. Our research focused on a case study performed in the Loukkos catchment, draining an area of 3730 km², located in the north of Morocco. Trend analysis of 8 to 62 years of precipitations was conducted based on statistical tests at about ten stations over the catchment. 20 to 70 years of temperature and discharge data were also analyzed. The time series were investigated using several non-parametric tests in order to characterize trends, to track down changes and their effect on agricultural land changes at the catchment scale. The present study highlights the impact of climate and catchment hydrology on agricultural practices and water resources used for irrigation. Analysis of precipitation indices showed that the temporal distribution of precipitation in the study area has changed since the 1970s. This change results from a reduction in precipitation, a shift in the hydrological year and a reduction in the number of wet days per year. Severe drought periods appear after the climatic rupture, which occurred around 1971. An increase in the intensity and frequency of droughts, in addition to an increase in the annual and seasonal average temperature (more than 1°C) were observed. Such changes contributed to agricultural practice modifications, with development of irrigated agriculture and later sowing period to adapt to the delay in the onset of the rains. For the future, the use of IPCC/CMIP5 climate projections for the Mediterranean region will help to evaluate how the precipitation indices will evolve. The impact of irrigation on stream discharge and groundwater recharge needs to be considered through agro-hydrological modeling including agricultural trajectory. Such tools will help to strengthen agricultural adaptation strategies and promote resilient farming practices.

Keywords: Precipitation trends, agricultural land use, water use for irrigation, agricultural adaptation strategies.

 
Assessment of the impact of INP and CCN perturbations on mixed-phase cloud microphysics using a spectral-bin model and reference observations
Authors: Lee Junghwa , Seifert Patric , Hashino Tempei , Schrödner Roland , Weger Michael , Senf Fabian , Knoth Oswald
Published: March 2020

Ice- and mixed-phase clouds largely contribute to global precipitation due to their high spatiotemporal coverage. It has been highlighted that aerosol-cloud interaction is a critical factor. However, our current understanding of the complexity of their microphysical properties is still rather limited.  

In this talk, we will discuss the impact of perturbations of the cloud condensation nuclei (CCN) and ice-nucleating particle (INP) on the structure and composition of mixed-phase clouds. The main methods are ground-based observations (i.e., Ka-band polarimetric cloud radar) as well as the spectral-bin microphysical methodology called AMPS (Advanced Microphysics Prediction System). Until now, significant efforts have been underway to improve microphysical processes in AMPS, such as the schemes for immersion freezing and habit prediction. Despite these endeavors, it is still challenging using modeling alone to resolve such complexity of microphysical processes due to many parameterizations and assumptions. In particular, the ice habit prediction system in AMPS is sensitive to the 3-D Eulerian advection scheme. Meanwhile, the Doppler-spectra derived from polarimetric cloud radar enables us to retrieve the hydrometeor habit of the significant signal peak in the Doppler spectrum of mixed-phase clouds. The synergy between the above mentioned advanced modeling approach and state-of-the-art observation techniques are in our study used to evaluate the effects of the CCN and INP perturbations on mixed-phase clouds. 

The steps are as follows. First of all, we will present the evaluation of a case study of a mixed-phase cloud by observation data. In the course of the work, AMPS is coupled with the German weather prediction system COSMO (Consortium for Small-scale Modeling) model. We choose an observation dataset from the ACCEPT (Analysis of the Composition of Clouds with Extended Polarization Techniques) field campaign in Cabauw, Netherlands, which was conducted during fall 2014. Also, we use the radar forward operator CR-SIM (Cloud Resolving Model Radar Simulator) that translates the dataset of simulation output into radar variables. Therefore, we will present direct comparisons between ground-based observation and modeling datasets. In the next step, AMPS is coupled with a simple 1-D dynamic core KiD (Kinematic Driver for microphysics intercomparison), so-called KiD-AMPS. In doing so, we will discuss the comparison with other schemes (i.e., Morrison 2-moment). Finally, in the frame of KiD-AMPS, we will debate the impact of the CCN and INP perturbations on mixed-phase clouds. 
Simulating stable water isotope derived information with the aid of artificial neural network applied on independent multivariate events
Authors: Chamorro Alejandro , Sahraei Amirhossein , Houska Tobias , Breuer Lutz
Published: March 2020

Abstract In recent years, stable isotopes of water have become a well-known tool to investigate runoff generation processes. The proper estimation of stable water isotope concentration dynamics based on a set of independent multivariate variables would allow the quantification of event water fraction in stream water even at times when no direct measurements of isotopes are available. Here we estimate stable water isotope concentrations and derived event water fractions in stream water over 40 precipitation events. A mobile field laboratory was set up to measure high-resolution (20 min) stable isotopes of water by laser spectrometry. Artificial neural networks (ANN) were established to model the same information. We consider precipitation and antecedent wetness hydrometrics such as precipitation depth, precipitation intensity and soil moisture of different depths as independent variables measured in the same high-temporal resolution. An important issue is the reduction of the deviation between observations and simulations in both the training and testing set of the network. In order to minimize this difference, various combinations of variables, dimensionalities of the training and testing sets and ANN architectures are studied. A k-fold cross validation analysis is performed to find the best solution. Further constraints in the iteration procedure are considered to avoid overfitting. The study was carried out in the Schwingbach Environmental Observatory (SEO), Germany. Results indicate a good performance of the optimized model, in which the dynamics of the isotope concentrations and the estimated event water fractions in the stream water were estimated. Compared to a multivariate linear model, the ANN-based model clearly outperformed the estimations showing the smallest deviation. The optimum network consists of 2 hidden nodes with a 5-dimensional input set. This strongly suggests that ANN-based models can be used to estimate and even forecast the dynamics of the isotope concentrations and event water fractions for future precipitation events.
Exploiting Copernicus Climate Change Service (C3S) to assess ongoing and future soil erosion over Italy
Authors: Rianna Guido , Santini Monia , Mancini Marco , Padulano Roberta , Noce Sergio
Published: March 2020

Soil erosion by water greatly affects Italy impacted by 24% of total soil loss of Europe, 33% of agricultural lands exposed, and costs, e.g. for crop production, up to about 600Meuro. Furthermore, expected increases in severity and magnitude of extreme precipitation events could exacerbate such an issue.

In this regard, rainfall information at very fine spatial and temporal resolution represents a key point; unfortunately, weather stations are not spread uniformly across regions and they uncommonly provide free data at sub-daily scale. Moreover, the reliable projections of how rainfall will change in the coming decades are hard to store and manage for non-experts.

In trying to overcome such a gap, Copernicus Climate Change Service (C3S) provides several tools. The C3S is part of the Copernicus Earth Observation Programme and is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission. In particular, Climate Data Store (CDS) hosts rainfall time series for the historical period and most recent decades from observational (E-OBS) and reanalysis (ERA5, ERA5-Land, UERRA) datasets, at (sub) daily time step and with horizontal resolution ranging from 31 km to 5.5 km. For the future, the simulations’ ensemble within EURO-CORDEX (resolution ~12 km, daily time step) are available for robust evaluations, i.e. to consider the uncertainty due to alternative greenhouse gas concentration scenarios and model chain used.

In this context, in the last months, C3S funded the Demo Case SOIL EROSION implemented by the CMCC Foundation and aimed at assessing ongoing and future soil loss by water erosion over Italy. The Demo Case is expected to develop further specific datasets and a web-application by exploiting products and tools also provided by Climate Data Store (CDS) infrastructure.

To assess soil losses, the largely adopted Revised Universal Soil Loss Equation (RUSLE) is selected. Such an empirical equation combines rainfall erosivity (R-factor), evaluated in this case by exploiting datasets in CDS, to soil susceptibility to erosion due to soil intrinsic properties but also to land cover, land management, and topography. Gridded datasets related to R-factor and soil losses will be then made available within the CDS catalog. Moreover, the web application will permit visualizing and retrieving trends and results for specific areas (e.g. NUTS) in the way of maps and graphs. In addition to the "Basic" mode, the Application is expected to support "what-if" analysis ("Advanced" mode) permitting to understand how variations in land use (C-factor) or management practice (P-factor) can influence soil losses at large scale under current and future conditions.
Revealing snow cover dynamics in the Hindu Kush Himalaya over the past decades
Authors: Naegeli Kathrin , Marin Carlo , Premier Valentina , Schwaizer Gabriele , Stengel Martin , Wu Xiaodan , Wunderle Stefan
Published: March 2020

Knowledge about the snow cover distribution is of high importance for climate studies, weather forecast, hydrological investigations, irrigation or tourism, respectively. The Hindu Kush Himalayan (HKH) region covers almost 3.5 million km2 and extends over eight different countries. The region is known as ‘water tower’ as it contains the largest volume of ice and snow outside of the polar ice sheets and it is the source of Asia’s largest rivers. These rivers provide ecosystem services, the basis for livelihoods and most importantly living water for drinking, irrigation, energy production and industry for two billion people, a fourth of the world’s population, living in the mountains and downstream.

The spatio-temporal variability of snow cover in the HKH is high and studies reported average snow-covered area percentage of 10–18%, with greater variability in winter (21–42%) than in summer (2–4%). However, no study systematically investigated snow cover metrics, such as snow cover area percentage (SCA), snow cover duration (SCD) or snow cover onset (SCOD) and melt-out day (SCMD), for the entire region so far. Here, we thus present unique in-sights of regional and sub-regional snow cover dynamics for the HKH based on almost four decades, an exceptionally long and in view of the climate modelling community valuable timeseries, of satellite data obtained within the ESA CCI+ Snow project.

Our results are based on Advanced Very High Resolution Radiometer (AVHRR) data, collected onboard the polar orbiting satellites NOAA-7 to -19, providing daily, global imagery at a spatial resolution of 5 km. Calibrated and geocoded reflectance data and a consistent cloud mask pre-processed and provided by the ESA Cloud_cci project as global 0.05° composites are used. The retrieval of snow extent considers the high reflectance of snow in the visible spectra and the low reflectance values in the short-wave infrared expressed in the Normalized Difference Snow Index (NDSI). Additional thresholds related to topography and land cover are included to derive the fractional snow cover of every pixel. A temporal gap-filling was applied to mitigate the influence of clouds. Reference snow maps from high-resolution optical satellite data as well as in-situ station data were used to validate the time series.
Development of a local nowcast magnetospheric ring current index based on geomagnetic observatory data
Authors: Kervalishvili Guram , Stolle Claudia , Matzka Jürgen
Published: March 2020

The Disturbance storm time (Dst) index is derived using the H-component perturbation on magnetometers from four observatories (Hermanus, Kakioka, Honolulu, and San Juan) near the Sq focus. The Dst index is a quantitative measure of geomagnetic activity (major disturbances are negative) that monitors the intensity of the magnetospheric ring current and it is derived and maintained by WDC Kyoto. The local nowcast index presented here is a geomagnetic index that is derived similarily to the Dst index for the each of the following low and mid-latitude observatories: Tristan da Cunha (South Atlantic, TDC), St. Helena (South Atlantic, SHE), Keetmanshoop (Namibia, KMH), Vassouras (Brazilian, VSS), Gan (Maldives, GAN) and Panagjurishte (Bulgaria, PAG). This local index is developed within the ESA’s SSA SWE G-ESC activity. Here, we assess the influence of the quiet-time Sq estimation on the local ring current index and the correlation of the index with other solar and geophysical parameters.
Out of the Lab, Into the Frying Pan: Understanding the Effect of Natural Groundwater Conditions on Bio-Based Ground Improvement Strategies
Authors: Hall Caitlyn , Rittmann Bruce , van Paassen Leon , Kavazanjian Edward
Published: March 2020

We are developing a biogeochemical model for microbial denitrification-driven ground improvement to account for t the complexities expected in the field, including microbial inhibition and competition. We will use this model to support Microbially Induced Desaturation and Precipitation (MIDP) via denitrification as a bio-based ground improvement strategy alternative considering different treatment recipes and natural groundwater composition. Current ground improvement techniques have limited utility underneath or near existing structures. Developing alternatives is becoming increasingly important as urbanization increases. Large, centralized populations and infrastructure are more vulnerable to threats by natural disasters and geologic hazards such as earthquake-induced liquefaction and flooding. Bio-based ground stabilization techniques may be less disruptive to deploy and monitor, allowing application underneath existing structures. MIDP is a two-stage ground-improvement process in which biogenic gas desaturation provides immediate improvement while calcium carbonate precipitation provides long term stability. MIDP influences the geochemical environment and the hydro-mechanical behavior of soils through biogenic gas production, precipitation of calcium carbonate, and biomass growth. All three components alter the biogeochemical environment and subsurface permeability, thereby affecting the transport of substrates and subsequent product formation. The products of MIDP mitigate liquefaction at the lab-scale. MIDP experimentation and modeling have primarily considered only the use of de-ionized water and simplified water composition. However, denitrifying microorganisms compete with alternative electron acceptors, like sulfate and iron, and are influenced by the environment’s pH and salinity which may impede the MIDP treatment. Our biogeochemical model can predict the products and by-products of MIDP treatment considering realistic groundwater conditions. The results of this model will be used to develop comprehensive treatment plans for upcoming field trials to demonstrate treatment effectiveness and develop best practices for future application.