bluuebunny/crossref_metadata_2025 huggingface dataset:
Flood forecast skill for Early Action: Results and Learnings from the development of the Early-Action Protocol for Floods in Uganda
Authors: Ficchì Andrea , Cloke Hannah , Speight Linda , Mulangwa Douglas , Amuron Irene , Ntale Emmanuel , Stephens Liz
Published: March 2021

Global flood forecasting systems are helpful in complementing local resources and in-country data to support humanitarians and trigger early action before an impactful flood occurs. Freely available global flood forecast information from the European Commission’s Global Flood Awareness System (GloFAS, a Copernicus EMS service) is being used by the Uganda Red Cross Society (URCS) alongside in-country knowledge to develop appropriate triggers for early actions for flood preparedness, within the Forecast-based Financing (FbF) initiative. To scale up the first FbF pilot to a national level, in 2020 URCS collaborated with several partners including the Red Cross Red Crescent Climate Centre (RCCC), the Uganda’s Ministry of Water and Environment, through the Directorate of Water Resources Management (DWRM), the Uganda National Meteorological Authority (UNMA), the 510 Global team and the University of Reading, through the UK-supported project Forecasts for Anticipatory Humanitarian Action (FATHUM). The new Early Action Protocol (EAP) for floods, submitted to the IFRC’s validation committee in September 2020, is now under review.

One of the aims of an EAP is to set the triggers for early action, based on forecast skill information, alongside providing a local risk analysis, and describing the early actions, operational procedures, and responsibilities. Working alongside our partners and practitioners in Uganda, we developed a methodology to tailor flood forecast skill analysis to EAP development, that could be potentially useful for humanitarians in other Countries and forecasters engaging with them. The key aim of the analysis is to identify skilful lead times and appropriate triggers for early action based on available operational forecasts, considering action parameters, such as an Action Lifetime of 30 days, and focusing on relevant flood thresholds and skill scores. We analysed the skill of probabilistic flood forecasts from the operational GloFAS (v2.1) system across Uganda against river flow observations and reanalysis data. One of the challenges was to combine operational needs with statistical robustness requirements, using relevant flood thresholds for action. Here we present the results from the analysis carried out for Uganda and the verification workflow, that we plan to make openly available to all practitioners and scientists working on the implementation of forecast-based actions.
Multifractal and joint multifractal analysis of the spatial variability of CO2 emission and other soil properties
Authors: Nogueira Deise Cristina Santos , Paz-González Antonio , Vidal-Vázquez Eva , de Moraes Mário Luiz Teixeira , Júnior José Marques , Montanari Rafael , Pereira Debora Marcondes Bastos , Júnior Newton La Scala , Panosso Alan Rodrigo
Published: March 2021

Soil is a major source and also a sink of CO2. Agricultural management practices influence soil  carbon sequestration. Identification of CO2 emission hotspots may be instrumental in implemented strategies for managing carbon cycling in agricultural soils. We used multifractal analysis to assess the spatial variability of both, soil CO2 emissions and associated soil physico-chemical attributes. The objectives of this study were: i) to characterize patterns of spatial variability of CO2 emissions and related soil properties using single multifractal spectra, and ii) to compare the scale‐dependent relationship between soil CO2 emissions and selected soil attributes by joint multifractal analysis. The study site was an experimental field managed as a sylvopastoral system, located in Selviria, South Mato Grosso state, Brazil. The soil was an Oxisol developed over basalt. Soil CO2 emission, soil water content and soil temperature were measured at 128 points every meter. In addition, soil was sampled at the marked points to analyze clay content, macro and microporosity, air free porosity, magnetic susceptibility, bulk density, and humification index of soil organic matter in absolute values and relative to organic carbon content. The generalized dimension, Dq versus q, and singularity spectra, f(α) versus α, of the spatial distributions of the 11 variables studied showed various degrees of multifractality. In general, the amplitude of the generalized dimension and singularity spectra was much higher for negative than for positive q order statistical moments. Joint multifractal spectra show a positive relationship between the scaling indices of the spatial distributions of CO2 and all of the other soil variables studied. However, contour plots were diagonally oriented for higher values of scaling indices and showed no distinct trend for the lower ones. Joint multifractal analysis corroborates different degrees of association between the scaling indices of CO2 and all of the remaining variables studied. It also showed that CO2 was stronger correlated at multiple scales than at the observation scale. Therefore, single scale analysis may not be sufficient to fully describe relationships between soil testing methods.Our study suggests that soil factors and processes driven the spatial variability of CO2 and the associated variables studied may be not very different.

 
Geospatial analysis of Arctic fires in the MODIS era: 2003–2020
Authors: Smith Thomas , McCarty Jessica , Turetsky Merritt , Parrington Mark
Published: March 2021

MODIS has provided an 18-year continuous record of global fire activity. Here we present a geospatial analysis of MODIS hotspots in the high latitudes of the northern hemisphere from 2003 through to 2020. By combining the hotspot data with multiple land-cover datasets relating to vegetation cover, permafrost, and peat, we investigate boreal and tundra wildfire regimes, including an assessment of a significant northwards shift and increase in fire activity in 2019 and 2020. We focus on the distribution of hotspots on high latitude peatlands and permafrost and the associated difficulties in confirming residual smouldering compustion of peat soils using current remote sensing technology.
Cloud droplet variability in the summertime in the southeast United States: day vs. night
Authors: Bougiatioti Aikaterini , Nenes Athanasios , Lin Jack , Brock Charles , de Gouw Joost , Liao Jin , Middlebrook Ann , Welti Andre
Published: March 2021

During the 2013 Southeast Nexus (SENEX) campaign, in-situ observational data were collected on board the NOAA WP-3D aircraft to study the aerosol-cloud droplet link and examine the sensitivity of the cloud droplet number to aerosol physicochemical parameters. In order to do so, observed aerosol number size distributions, chemical composition and vertical-velocity distributions were introduced into a state-of-the-art cloud droplet parameterization from which cloud droplet number and cloud maximum supersaturations were derived. We find that the standard deviation of the vertical velocity (σw) exhibits significant diurnal variability ranging from 0.16 m s-1 during nighttime to over 1.2 m s-1 during day. Total aerosol number (Na) covaries with σw , with lower values observed during nighttime. The covariance between σw and Na enhances the apparent response of Nd to changes in Na levels by a factor of 5. For the same “cleaner” environments where Na values are limited and not impacted by local sources, the relative response of Nd to σw is almost twice as great during night, compared to the day (24% during day vs. 42% during night). On the other hand, in environment with enhanced concentrations, especially of accumulation-mode particles, the majority of droplet number variability is attributed to changes in total aerosol number rather than changes in σw. Chemical composition is found to on-average have a limited effect on Nd variability (4%). Finally, we identify an upper limit to the number of droplets that can form in clouds which depends only on σw independently from total aerosol number. Doubling σw from 0.2 to 0.3 m s-1increases this limiting droplet number by 52%.When Nd values approach this upper limit the observed droplet variability is driven by σw and, subsequently, by vertical-velocity changes only. Therefore only by using this -σw relationship in regions where velocity-limited conditions are expected, σw can be estimated from retrievals of droplet number and vice versa.
Debris‐flow and anthropogenic disturbance on 10Be concentration in mountain streams with contrasting structural geomorphic connectivity
Authors: Brardinoni Francesco , Grischott Reto , Kober Florian , Morelli Corrado , Christl Marcus
Published: March 2021

This study examines the sensitivity of 10Be concentrations to debris‐flow and anthropogenic perturbations in steep mountain streams of the Eastern Alps, characterized by contrasting structural geomorphic connectivity. Using cosmogenic 10Be as a tracer for functional geomorphic connectivity, we conduct sampling replications across four seasons in Gadria, Strimm and Allitz Creek. Sampling sites encompass a range of structural connectivity configurations, including the conditioning of a sackung, all assessed through a geomorphometric index (IC). By combining information on contemporary depth of erosion and sediment yield, disturbance history and post‐LGM (Last Glacial Maximum) sedimentation rates at the Gadria fan, we constrain the effects of debris‐flow disturbance on 10Be concentrations along Gadria Creek. Here, we argue that bedrock weakening imparted by the sackung promotes high depth of erosion. Consequently, we show that debris flows recruit sediment beyond the critical depth of spallogenic production (e.g., >3m), which in turn, episodically, due to predominantly muogenic production pathways, lowers 10Be concentration by a factor of 4, for over 2 years. In contrast, steady erosion in Strimm Creek yields very stable 10Be concentrations through time. In Allitz Creek, we observe two‐ to fourfold seasonal fluctuations in 10Be concentrations, which we explain as the combined effects of water diversion and hydraulic structures on sediment mixing. We further show that 10Be concentration correlates inversely with the IC index, where sub‐basins characterized by high concentrations (long residence times) exhibit low IC values (structurally disconnected) and vice versa, implying that, over millennial time scales a direct relation exists between functional and structural connectivity, and that the IC index performed as a suitable metric. In terms of landscape evolution, we argue that the sackung, by favouring intense debris‐flow activity across the Holocene, as recorded by the paraglacial sedimentary wave associated with the formation of the Gadria fan, has aided rapid postglacial reshaping of the Gadria source basin, which currently exhibits a topographic signature characteristic of unglaciated debris flow-dominated systems.
The ERATOSTHENES CoE in the PollyNET:First observations of the PollyXT-CYP at Limassol, Cyprus
Authors: Mamouri Rodanthi-Elisavet , Nisantzi Argyro , Engelman Ronny , Bühl Johannes , Seifert Patric , Baars Holger , Yin Zhenping , Hadjimitsis Diofantos , Ansmann Albert
Published: March 2021

A new generation PollyXT lidar system start on 27th of October 2020, continuous operation, at Limassol, Cyprus.

The lidar system will become a key component within the EXCELSIOR H2020 EU Teaming project coordinated by the Cyprus University of Technology. The mission of the EXCELSIOR project is to upgrade the Remote Sensing & Geo-Environment Lab, established within the Faculty of Engineering & Technology of the Cyprus University of Technology, into a sustainable, viable and autonomous Centre of Excellence, called the ERATOSTHENES Center of Excellence (ECoE).

The PollyXT-CYP will be hosted by the ERATOSTHENES CoE for its permanent operation aiming to link the Centre to ACTRIS and PollyNet. Its task will be to document the complex mixture of the different aerosol species and clouds over the Eastern Mediterranean.

The system is continuously running and since the first observations in Limassol, PollyXT-CYP demostrates the complex aerosol conditions over Cyprus. For eaxample, between the 27th of October to the 1st of November 2020, the lidar observed smoke plumes from the extreme wildfires on the west coast of the U.S. The smoke travelled over the Atlantic Ocean and triggered the heterogenous ice formation at the height of 10km. Saharan dust was also detected between 2-5km and liquid clouds were formed on the top of the dust layer.

In this study we will present selected cases of unique atmospheric structures from the first months of continuous operation over Cyprus as well as optical and geometrical properties of the aerosol layers.

The PollyXT-CYP will be a key research infrastructure of the Cyprus Atmospheric Remote Sensing Observatory (CARO). CARO will consist of two high-tech containers housing the PollyXT-CYP lidar and state-of-the art doppler lidar, cloud radar and radiometric equipment which will be used to measure the air quality, the dust transport, and the cloud properties over Cyprus. The CARO is planned to become National Facility of the Republic of Cyprus for Aerosol and Cloud Remote Sensing Observations.

Acknowledgements

The authors acknowledge the EXCELSIOR project that received funding from the European Union [H2020-WIDESPREAD-04-2017:Teaming Phase2] project under grant agreement no. 857510, and from the Republic of Cyprus. CUT team acknowledge the Research and Innovation Foundation of Cyprus for the financial support through the SIROCCO (EXCELLENCE/1216/0217) and AQ-SERVE (INTERGRATED/0916/0016) projects. The PollyXT-CYP was funded by the German Federal Ministry of Education and Research (BMBF) via the PoLiCyTa project.
Reassessing global ice volume: uncertainty and structure in sea level records
Authors: Hibbert Fiona D. , Williams Felicity , Rohling Eelco
Published: March 2021

Geologically recorded sea-level variations represent the sum total of all contributing processes, be it known or unknown, and may thus help in finding the full range of future sea-level rise. Significant sea-level-rise contributions from both northern and southern ice sheets are not unprecedented in the geological record and offer a well-constrained range of natural scenarios from intervals during which ice volumes were similar to or smaller than present (i.e., interglacial periods), to intervals during which total ice volume was greater (i.e., glacial periods).

The last deglaciation is the most recent period of widespread destabilisation and collapse of major continental ice sheets. Records spanning the last deglaciation (as well as the ice volume maxima) are few, fragmentary and seemingly inconsistent (e.g., the timing and magnitude of melt-water pulses), in part due to locational (tectonic and glacio-isostatic) as well as modern analogue considerations (e.g., palaeo-water depth or facies formation depth). We present a new synthesis of sea-level indicators, with particular emphasis on the geological and biological context, as well as the uncertainties of each record. Using this new compilation and the novel application of statistical methods (trans-dimensional change-point analysis, which avoids “overfitting” of noise in the data), we will assess global ice-volume changes, sea-level fluctuations and changes in climate during the last deglaciation. Finally, we discuss the implications of these uncertainties on our ability to constrain past cryosphere changes.
Climate change in the vineyard: perspectives for pest species in the region of Neuchatel
Authors: Schneider Léonard , Comte Valentin , Sneiders Baptiste , Rebetez Martine
Published: March 2021

Global warming increases the need for local climatic studies in wine-producing areas. Winegrowers have to develop strategies to adapt their activities to new climatic conditions and to their various effects on vine culture. Among them, distribution and population dynamics of pest species are likely to change. New species could reach the temperate regions, and some native species could create more damages than previously in the vineyards. In Western Europe, the distribution of the American grapevine leafhopper Scaphoideus titanus has been observed to shift northwards during the last decades (Boudon and Maixner 2007). Plurivoltin species such as the European grapevine moth Lobesia botrana could produce more generations per year (Gutierrez et al. 2018), creating potentially more damages on grapes. To help winegrowers, it is crucial to lead research at local scale, taking into account microclimatic specificities of the vineyards (Mozell and Thach 2014).

 

In this study, we examine temperature trends during the growing season in the region of Neuchatel and their potential impacts on major vine pest species. We focus on the American grapevine leafhopper and on the European grapevine moth. The American grapevine leafhopper is already established in the Lake Geneva area and could soon reach the Neuchatel area, while the European grapevine moth is already present in the Neuchatel vineyard. We use temperature data over the last 40 years (1980-2019) and two climatic scenarios to assess present suitability for pest development and the perspectives for the next decades.

 

 

REFERENCES

Boudon, E. & M. Maixner. 2007. Potential effects of climate change on distribution and activity of insect vectors of grapevine pathogens. In International and multi-disciplinary" Global warming, which potential impacts on the vineyards?".

Gutierrez, A. P., L. Ponti, G. Gilioli & J. Baumgärtner (2018) Climate warming effects on grape and grapevine moth (Lobesia botrana) in the Palearctic region. Agricultural and Forest Entomology, 20, 255-271.

Mozell, M. R. & L. Thach (2014) The impact of climate change on the global wine industry: Challenges & solutions. Wine Economics and Policy, 3, 81-89.

 
Wave-Vortex Interactions in the Submesoscale
Authors: Uncu Jeffrey , Grisouard Nicolas
Published: March 2021

The Surface Water and Ocean Topography (SWOT) mission is the next generation of satellite altimetry, set to launch in early 2022. It will be the first of its kind to provide global sea surface height (SSH) measurements fine enough to begin resolving the submesoscale. In this newly resolvable regime, “slow” flows (jets, vortices…) interact with internal waves by redistributing wave energy to other wave-vectors and frequencies. This introduces the challenge of distinguishing “slow” flows from waves, which is of key importance for inferring ocean circulation, from SSH measurements. I run numerical simulations of the one layer rotating shallow water equations to model the interaction between a single internal tide mode and vortices in (cyclo)geostrophic balance to characterize scattering and map its relevant parameter space. Preliminary results show wave scattering by vortices with Rossby numbers ranging from 0.1-4 that are not explained by the standard methods (frozen-field approximation, ray tracing…) which have been successful in the mesoscale. We find that the Rossby number, the Burger number, and the ratio of the length and velocity scales of the wave and vortex are all necessary to characterize the interaction in submesoscale regimes. Harmonic analysis is used to highlight the direction of the scattered wave energy.
Satellite Detection of Ghost Nets and Plastic Debris in Pacific Atolls
Authors: Ling Yangrong , Biermann Lauren , Manuel Mark , Ramirez Ellen , Coates Austin , Gallagher Megan , Streett Davida
Published: March 2021

Since 2014, the NOAA Satellite Analysis Branch has used high resolution optical satellite imagery in an effort to detect ghost nets (derelict fishing gear) and other large plastic debris in the Pacific Ocean and its atolls in support of clean-up efforts (by the NOAA Pacific Islands Fisheries Science Center, Ocean Voyages Institute, etc.). Until recently, reliable detection has proven challenging. With the application of Worldview imagery matched to in situ information on known net locations, we have been able to extract spectral signatures of floating plastics and use these to detect and identify other instances of plastic debris. Using ENVI’s Spectral Angle Mapper (SAM) target detection method, a number of likely locations of nets/plastics in the Pearl and Hermes atoll in the Northwestern Hawaiian Islands (NWHI) were highlighted. The resulting locations of the 41 debris detections were strikingly similar to the distributions along the coast reported in surveys, and are consistent with those that would be expected due to the seasonal ocean currents. This satellite imagery analysis procedure will be repeated shortly before the next NWHI clean-up effort, which will better enable us to support the removal of ghost nets and other marine plastics, and also assess the accuracy and rapid reproducibility of the technique.
Anisotropic statistics of Lagrangian structure functions and Helmholtz decomposition
Authors: Wang Han , Bühler Oliver
Published: March 2021

Second-order velocity structure functions are commonly estimated from Lagrangian tracer trajectories.  A Helmholtz decomposition of these structure functions, which separates their divergent and rotational components, can indicate the robustness of geostrophic balance at different scales, and serves as a building block for analysis of scale-dependent energy distributions. We present a new method to estimate second-order horizontal velocity structure functions, as well as their Helmholtz decomposition, from sparse data collected by Lagrangian observations.   The novelty compared to existing methods is that we allow for anisotropic statistics in the velocity field as well as in the distribution of the Lagrangian trackers. We conduct the analysis through the lens of azimuthal Fourier expansions, and find Helmholtz decomposition formulae targeted at individual Fourier modes. We also identify an improved statistical angle-weighting technique that generally increases the accuracy of structure function estimations in the presence of anisotropy. The new methods are tested against synthetic data and applied to surface drifter data sets such as LASER and GLAD. Importantly, the new method does not require extra measurements compared to existing methods based on isotropy.
On the Role of Forestry in Climate Change Mitigation
Authors: Appiah Mensah Alex , Petersson Hans , Berndes Göran , Egnell Gustaf , Ellison David , Lundblad Mattias , Lundmark Tomas , Lundström Anders , Stendahl Johan , Wikberg Per-Erik
Published: March 2021

Long-standing debates over the benefits of forest conservation vs. those of substitution and forest resource use continue to occupy attention in Europe and beyond. Moreover, many argue the carbon sequestration benefits of standing forest are greater than those from forest resource use and replanting. To study this question, we generate long-term scenario analyses based on different forest management strategies in Sweden, in particular comparing increasing forest use and increasing land set-asides over 100, 200 and 500 year cycles. We find that the cost of increasing land set-asides is reflected in a significant loss of the carbon benefits created by forest use (substitution and carbon sequestration). We explain this outcome through the loss of additional growth that occurs as forest in land set-asides matures and eventually reaches a steady state. For the Swedish forest, these costs are significant and may amount to the loss (lost opportunity) of annually providing and additional -14 MtCO2e in net annual removals. The EU-based LULUCF carbon accounting framework, however, does not recognize this benefit and thus may effectively encourage land set-asides at the expense of real, measurable forest and forest resource-based climate change mitigation.
The Role of Sublimation on the Surface Mass Balance of the Interior Greenland Ice Sheet
Authors: Dietrich Laura , Steen-Larsen Hans Christian , Agosta Cécile , Fettweis Xavier , Faber Anne-Katrine , Wahl Sonja
Published: March 2021

Precipitation along with sublimation and deposition are the main contributors to the surface mass balance (SMB) in the accumulation area of the Greenland Ice Sheet (GrIS). However, precipitation events are rare and intermittent. In between precipitation events the surface snow continuously undergoes sublimation and deposition. Recent studies imply that these surface exchange processes influence the isotopic composition of the surface snow which is later archived as a climate record in ice cores. In order to understand the possible implications on the recorded climate signal, sublimation needs to be quantified on a local scale.

Here we present simulated SMB components for eight ice core drilling sites on the GrIS using the regional climate model MAR (Modèle Atmosphérique Régional). We validated MAR against in-situ flux observations at the East Greenland Ice Core Project site and found a high sensitivity of sublimation to the downward long wave flux and to the parameterization of the surface roughness length. We propose a surface roughness length optimized for the interior of the GrIS which is supported by our observations.

Our results show that in the GrIS accumulation area the mass turnover via sublimation and deposition can reach the same order of magnitude as precipitation. This highlights the importance of a better understanding of how the climate signal is imprinted in the surface snow isotopic composition.
Underground heritage valorization of camerano's cave in center italy a case of transition towards projects integrating the local community and landscape 
Authors: Pierdicca Roberto , Malinverni Eva Savina , di Stefano Francesco , Pace Giuseppe , Fioretti Ilaria , Galli Andrea , Marcheggiani Ernesto , Paci Francesco
Published: March 2021

Underground4Value is a COST Action (CA18110) aiming at providing adequate cultural, scientific and technical knowledge of the UBH concerning different aspects (i.e. archaeology, geotechnics, history, urban planning, architecture, cultural anthropology, economics, tourism, sustainable development), in a multi-disciplinary context. So far there are 30 participant countries, moreover Tunisia and Mexico.

The overarching idea is supporting Underground Built Heritage (UBH) conservation, valorization, management, and fostering decision-making through community-led development. The main challenge is how to stimulate social innovations in local communities through heritage management approaches.

One of the living lab stemmed by the activities of the Cost Action is in center Italy, where are many other hypogea with different function: water reservoir, military-strategic, food storage, cultural or religious function, mines or quarries. Among them the city of Camerano represents a local heritage and a landmark for its network of connected built underground spaces. The local community's self-initiative and the determination and far-sightedness of the local authority allowed to differentiate the local tourism offer leading to success in terms of tourism attractiveness, with more than 25'000 visitors per year. First reliable records date 1327 AC.

Special attention is given to the digital dimension of Cultural Heritage. An asset for the next decade, in particular after the COVID-19 pandemic. Surveys of the interior environment of the caves were carried out using two laser instruments in different acquisition modes. The use of the static laser scanner requires a longer time for both the acquisition and the subsequent processing phases. The use of a mobile laser scanner, on the other hand, makes it possible to scan and record the underground environment in real time in just a few hours, thus providing a fast and agile solution. This means that it is possible to go more often for constant and rapid monitoring. The integration of spherical photos taken along the route of the caves themselves offers the possibility of creating a virtual reality (VR) tour that can be integrated with a 3D model of the entire underground environment. This allows the caves to be visited from a virtual point of view when they are closed for restoration work or in cases of emergencies, such as pandemic one. 
Observing avalanche dynamics with Distributed Acoustic Sensing
Authors: Fichtner Andreas , Edme Pascal , Paitz Patrick , Lindner Nadja , Hohl Michael , Huguenin Pierre , Sovilla Betty , Roig-Lafon Pere , Surinach Emma , Walter Fabian
Published: March 2021

Avalanche research requires comprehensive measurements of sudden and rapid snow mass movement that is hard to predict. Automatic cameras, radar and infrasound sensors provide valuable observations of avalanche structure and dynamic parameters, such as velocity. Recently, seismic sensors have also gained popularity, because they can monitor avalanche activity over larger spatial scales. Moreover, seismic signals elucidate rheological properties, which can be used to distinguish different types of avalanches and flow regimes. To date, however, seismic instrumentation in avalanche terrain is sparse. This limits the spatial resolution of avalanche details, needed to characterise flow regimes and maximise detection accuracy for avalanche warning.

As an alternative to conventional seismic instrumentation, we propose Distributed Acoustic Sensing (DAS) to measure avalanche-induced ground motion. DAS is based on fibre-optic technology, which has previously been used already for environmental monitoring, e.g., of snow avalanches. Thanks to recent technological advances, modern DAS interrogators allow us to measure dynamic strain along a fibre-optic cable with unprecedented temporal and spatial resolution. It therefore becomes possible to record seismic signals along many kilometres of fibre-optic cables, with a spatial resolution of a few metres, thereby creating large arrays of seismic receivers. We test this approach at an avalanche test site in the Valleé de la Sionne, in the Swiss Alps, using an existing 700 m long fibre-optic cable that is permanently installed underground for the purpose of data transfer of other, independent avalanche measurements.

During winter 2020/2021, we recorded numerous snow avalanches, including several which reached the valley bottom, travelling directly over the cable during runout. The DAS recordings show clear seismic signatures revealing individual flow surges and various phases/modes that may be associated with roll waves and avalanche arrest. We compare our observations to state-of-the-art radar and seismic measurements which ideally complement the DAS data.

Our initial analysis highlights the suitability of DAS-based monitoring and research for avalanches and other hazardous granular flows. Moreover, the clear detectability of avalanche signals using existing fibre-optic infrastructure of telecommunication networks opens the opportunity for unrivalled warning capabilities in Alpine environments.
General Ecosystem Models, moving towards modelling responses and effects of whole ecosystems
Authors: Harfoot Mike , Tittensor Derek , Hoeks Selwyn , Krause Jens , Arneth Almut , Doughty Chris , Abraham Andrew
Published: March 2021

Ecosystems are facing unprecedented pressures as a result of human activities. At the same time, ecology as a discipline is increasingly demanding more mechanistic understanding of what causes observed ecological patterns, in part for the development of the science but also to help mitigate impacts. Here, I will present the Madingley Model (www.madingleymodel.org), a General Ecosystem Model that aims to provide a mechanistic understanding of how ecosystems, on land and in the seas, are structured and how they function, and for how anthropogenic changes might alter that structure and function. I will discuss the model’s current capabilities, how it is being used, and highlight some necessary and exciting future directions for development.
Rupture analysis of the 2020 Petrinja earthquake based on seismological observations
Authors: Causse Mathieu
Published: March 2021

Here, I use seismological observations (~70 broadband stations at distances between 100 and 400 km from the source) to characterize the rupture properties of the Petrinja mainshock (Mw 6.4). First, I perform a spectral analysis of the P-waves to compute the corner frequency. In order to remove the wave propagation effects and isolate the source properties, I use the largest foreshocks and aftershocks (Mw>4) as empirical Green’s functions (EGFs). Assuming a Brune’s source model, the obtained stress drop is ~20 MPa. This rather large value is in agreement with the short rupture length of ~8 km inferred by InSAR data (Ganas et al. 2021). In addition, the weak azimuthal variations of the corner frequencies indicates a bilateral rupture, that is a rupture nucleating close to the fault center. Second, I compute the apparent source time functions (i.e. the source time functions “seen” from any station) using an EGF deconvolution approach. The results indicate an average rupture duration of 5-6 s with weak azimuthal variation of the apparent rupture duration, in agreement with the spectral analysis. Finally, I perform a Bayesian inversion of the apparent source function, in order to obtain a kinematic model of the rupture propagation (slip distribution, rupture velocity). The preliminary results reveal a slow velocity of the rupture propagation. Such a slow rupture velocity associated with a large stress drop has been observed on other faults with slow slip rates (e.g. Causse et al. 2017). This work provides insight on the rupture process of this major event on a poorly documented fault. I am fully open for collaborations to further develop and enrich this study.

References
Causse, M., G. Cultrera, L. Moreau, A. Herrero, E. Schiapappietra and F. Courboulex. Bayesian rupture imaging in a complex medium. The 29 May 2012 Emilia, Northern Italy, earthquake (2017), Geophysical Research Letters, DOI : 10.1002/2017GL074698.
Ganas, A., Elias, P., Valkaniotis, S., Tsironi, V., Karasante, I., Briole, P., 2021, Petrinja earthquake moved crust 10 feet, Temblor, http://doi.org/10.32858/temblor.156
Impact of the Chamoli disaster on flood Plain and water quality along the Himalayan rivers
Authors: Meena Sansar , Chauhan Akshansha , Bhuyan Kushanav , Singh Ramesh P.
Published: March 2021

The Himalayan rivers are glacier-fed and are vulnerable to devastating flash floods caused by damming of landslides and outbreak of glacial lakes. On 7 February 2021, around 10:30 am IST, a huge block of glacier mass broke from the Nanda Ghunti glacier. It is evident from the multi-temporal satellite imageries from Planet Scope that snow dust deposited in the affected area. During the course of the event, a huge amount of debris along with broken glacial fragments flooded the Rishi Ganga river and washed away the Hydropower plants; Rishi Ganga and Tapovan, more than 71 people were killed, and about 100 people are still missing. Detailed analysis of optical and radar data has been carried out to show the impact of the rockslide, changes in the surface characteristics of the source region, flood plains of the river and water quality of the Himalayan rivers (Alaknanda and Ganga). We have used five different indices Modified Normalized difference water index (MNDWI), Normalized difference vegetation index (NDVI), Enhanced vegetation index (EVI), Normalized difference turbidity Index (NDTI), and Normalized difference chlorophyll index (NDCI), that show pronounced changes in water quality and flood plain at the four different sections of the river. The spectral reflectance and backscattering coefficients derived from high-resolution Planet scope and Sentinel 1 SAR data show characteristics behaviour of the flood plain and water quality. Further, we have also found changes in the water quality of several canals after the Chamoli disaster event as the flood gates were closed to stop the deposit of sediments in the canal.
Resolving pre-collapse slope motion at the February 2021 Chamoli rock-ice avalanche via feature tracking of optical satellite imagery
Authors: Van Wyk de Vries Maximillian , Bhushan Shashank , Shean David , Berthier Etienne , Deschamps-Berger César , Gascoin Simon , Jacquemart Mylène , Kääb Andreas , Shugar Dan
Published: March 2021

On the 7th of February 2021, a large rock-ice avalanche triggered a debris flow in Chamoli district, Uttarakhand, India, resulting in over 200 dead or missing and widespread infrastructure damage. The rock-ice avalanche originated from a steep, glacierized north-facing slope with a history of instability, most recently a 2016 ice avalanche. In this work, we assess whether the slope exhibited any precursory displacement prior to collapse. We evaluate monthly slope motion over the 2015 and 2021 period through feature tracking of high-resolution optical satellite imagery from Sentinel-2 (10 m Ground Sampling Distance) and PlanetScope (3-4 m Ground Sampling Distance). Assessing slope displacement of the underlying rock is complicated by the presence of glaciers over a portion of the collapse area, which display surface displacements due to internal ice deformation. We overcome this through tracking the motion over ice-free portions of the slide area, and evaluating the spatial pattern of velocity changes in glaciated areas. Preliminary results show that the rock-ice avalanche bloc slipped over 10 m in the 5 years prior to collapse, with particularly rapid slip occurring in the summer of 2017 and 2018. These results provide insight into the precursory conditions of the deadly rock-ice avalanche, and highlight the potential of high-resolution optical satellite image feature tracking for monitoring the stability of high-risk slopes.
Testing physics and statics based hybrid ETAS models
Authors: Sharma Shubham , Nandan Shyam , Hainzl Sebastian
Published: March 2021

Currently, the Epidemic Type Aftershock Sequence (ETAS) model is state-of-the-art for forecasting aftershocks. However, the under-performance of ETAS in forecasting the spatial distribution of aftershocks following a large earthquake make us adopt alternative approaches for the modelling of the spatial ETAS-kernel. Here we develop a hybrid physics and statics based forecasting model. The model uses stress changes, calculated from inverted slip models of large earthquakes, as the basis of the spatial kernel in the ETAS model in order to get more reliable estimates of spatiotemporal distribution of aftershocks. We evaluate six alternative approaches of stress-based ETAS-kernels and rank their performance against the base ETAS model. In all cases, an expectation maximization (EM) algorithm is used to estimate the ETAS parameters. The model approach has been tested on synthetic data to check if the known parameters can be inverted successfully. We apply the proposed method to forecast aftershocks of mainshocks available in SRCMOD database, which includes 192 mainshocks with magnitudes in the range between 4.1 and 9.2 occurred from 1906 to 2020. The probabilistic earthquake forecasts generated by the hybrid model have been tested using established CSEP test metrics and procedures. We show that the additional stress information, provided to estimate the spatial probability distribution, leads to more reliable spatiotemporal ETAS-forecasts of aftershocks as compared to the base ETAS model.
Impairing pipe-to-stream connectivity in a heavily degraded blanket bog: the results of a pipe outlet blocking trial
Authors: Regensburg Taco , Chapman Pippa , Pilkington Michael , Chandler David , Evans Martin , Holden Joseph
Published: March 2021

As part of the EU-funded MoorLIFE2020 project, we assessed the impact of pipe blocking on the hydrological responses at pipe and stream level in a heavily degraded blanket bog in the Peak District of northern England. The study catchment, Upper North Grain, has a blanket peat cover up to four meters thick at places, with a branching network of deep gullies that incise into the bedrock. Earlier survey work has shown piping to be ubiquitous to the site, with 346 pipe outlets found and a mean frequency of 22.8 km-1 gully bank. Topographic position was an important control on the size and depth of pipe outlets. Pipe outlets on streambanks with signs of headward retreat (head pipes) were significantly larger and closer to the peat surface compared to pipe outlets that issued onto uniform streambank edges (edge pipes). In the context of peatland restoration, managers are keen to understand how these pipes contribute to hydrological responses of streams and associated export of fluvial carbon borne away in stream waters. However, little is known about pipe-to-stream connectivity and whether blocking methods used to impede flow in open ditch networks and gullies also work on pipe networks. Results will be presented on a before-after-control-intervention experiment in which we investigated: 1) whether impeding drainage from pipe networks alters the streamflow response at the catchment outlet; 2) how such intervention affects the hydrological functioning of the pipe network and the surrounding peat; 3) the scale of fluxes of particulate organic carbon (POC) and dissolved organic carbon (DOC) from a head pipe before and after pipe outlet blocking; and 4) whether pipe outlet blocking alters DOC and POC export in streams. Four blocking methods were trialed: peat-plugs, peat and stone, wooden planks, and plastic pilling. Results show that pipe outlet blocking led to new pipe outlets appearing or seepage around blocks within 90 days of blocking. Over a period of 17 months, four individual pipe outlets (2 head and 2 edge) produced 11.3 % of streamflow. Head pipes produced significantly larger peak flows and storm contributions to streamflow compared to edge pipes. A distinctive distance-decay effect of the water table around pipe outlets was observed, with deeper water tables around the outlets of edge pipes. To avoid further erosion in gully edge zones, we propose that future pipe blocking efforts prioritize increasing the residence time of pipe water by forming surface storage higher up in the pipe network. Further results will be presented from ongoing analyses of the effect of pipe blocking on the export of particulate and dissolved organic carbon from pipes and streams.
Revisiting China’s methane emissions from coal sector
Authors: Cui Duo
Published: March 2021

Methane emissions associated with human activities contributes significantly to global climate change. China is the world largest methane emitter and the coal mining sector is the largest contributor. Recent atmospheric inversion by Miller et al. using spaceborne column CH4 concentration measurements inferred that emissions in China rose by more than 1.0 Tg CH4 yr−1 from 2010 to 2017 due to the contribution of fossil fuel, especially from coal sector. Here we revisit methane emissions from the coal sector in China by comparing a sectorial bottom up emission inventory (2005-2019) with the results from another ensemble of CH4 inversions using GOSAT satellite data during 2011-2017. During that period, the bottom up inventory gives an average emission of 17.9 Tg CH4 yr-1 and the median of all inversions of 18.6 Tg CH4 yr-1, with a range of [10.8, 25.6] corresponding to the min-max of all inversions and the use of two gridded maps of emissions to separate the coal sector from total emissions in each inversion grid cell. We confirm the upward trend in methane emissions from the coal sector from 2005 to 2019 observed by Miller et al. In addition, we show that trend accelerated after 2016 as consistently found in the bottom-up inventory and top-down inversions approaches. However, during the period of 2010-2017, the bottom-up inventory and top-down inversions showed opposite trends in emissions. Especially during the period of 2014-2016, emissions from coal sector decreased at a rate of 0.8 Tg CH4 yr-1 using bottom up inventory, while emissions from top-down inversions maintained a relatively high growth rate at 0.4 Tg CH4 yr-1. Suggesting possible underestimation of the emission by bottom up inventories. In addition, we estimates the contribution of abandoned mines to the growth of methane emissions from coal sector was around 20%, we also show a COVID-19 pandemic related sharp dip in methane emission from the coal sector in Feb 2020 and rebound since in April 2020 based on the estimation of monthly bottom-up inventory.
Potential Driving Factors on Surface Solar Radiation Trends over China in Recent Years
Authors: Wang Qiuyan , Zhang Hua , Wild Martin
Published: March 2021

The annual mean surface solar radiation (SSR) trends under all-sky, clear-sky, all-sky-no-aerosol, and clear-sky-no-aerosol conditions as well as their possible causes are analyzed during 2005-2018 over China based on different satellite-retrieved datasets to determine the likely drivers of the trends. The results confirm clouds and aerosols as the major contributors to such all-sky SSR trends over China but playing different roles over sub-regions. Aerosol variations during this period result in a widespread brightening, while cloud effects show opposite trends from south to north. Moreover, aerosols contribute more to the increasing all-sky SSR trends over northern China, while clouds dominate the SSR declines over southern China. A radiative transfer model is used to explore the relative contributions of cloud cover from different cloud types to the all-types-of-cloud-cover-induced (ACC-induced) SSR trends during this period in four typical sub-regions over China. The simulations point out that the decreases in low-cloud-cover (LCC) over the North China Plain are the largest positive contributor of all cloud types to the marked annual and seasonal ACC-induced SSR increases, and the positive contributions from both high-cloud-cover (HCC) and LCC declines in summer and winter greatly contribute to the ACC-induced SSR increases over East China. The contributions from medium-low-cloud-cover (mid-LCC) and LCC variations dominate the ACC-caused SSR trends over southwestern and South China all year round, except for the larger HCC contribution in summer.