bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a swath-to-swath sea-ice drift product for the Copernicus Imaging Microwave Radiometer (CIMR) mission.
Authors: Lavergne Thomas , Piñol Solé Montserrat , Down Emily , Donlon Craig
Published: March 2021

Across spatial and temporal scales, sea-ice motion has implications on ship navigation, the sea-ice thickness distribution, sea ice export to lower latitudes and re-circulation in the polar seas, among others. Satellite remote sensing is an effective way to monitor sea-ice drift globally and daily, especially using the wide swaths of passive microwave missions. Since the late 1990s, many algorithms and products have been developed for this task. Here, we investigate how processing sea-ice drift vectors from the intersection of individual swaths of the Advanced Microwave Scanning Radiometer 2 (AMSR2) mission compares to today’s status-quo (processing from daily averaged maps of brightness temperature).

We document that the “swath-to-swath” (S2S) approach results in many more (two orders of magnitude) sea-ice drift vectors than the “daily-maps” (DM) approach. These S2S vectors also validate better when compared to trajectories of on-ice drifters. For example, the RMSE of the 24 hour Arctic sea-ice drift is 0.9 km for S2S vectors, and 1.3 km for DM vectors from the 36.5 GHz imagery of AMSR2.

Through a series of experiments with actual AMSR2 data and simulated Copernicus Imaging Microwave Radiometer (CIMR) data, we study the impact that geo-location uncertainty and imaging resolution have on the accuracy of the sea-ice drift vectors. We conclude by recommending that a “swath-to-swath” approach is adopted for the future operational Level-2 sea-ice drift product of the CIMR mission. We outline some potential next steps towards further improving the algorithms, and making the user community ready to fully take advantage of such a product.

This work is currently under revision at EGU The Cryosphere as https://tc.copernicus.org/preprints/tc-2020-332/
Building damage impact forecasting for winter windstorms in Switzerland
Authors: Röösli Thomas , Bresch David N.
Published: March 2021

Weather extremes can have high socio-economic impacts. Better impact forecasting and preventive action help to reduce these impacts. In Switzerland, the winter windstorms caused high building damage, felled trees and interrupted traffic and power. Events such as Burglind-Eleanor in January 2018 are a learning opportunity for weather warnings, risk modelling and decision-making.

We have developed and implemented an operational impact forecasting system for building damage due to wind events in Switzerland. We use the ensemble weather forecast of wind gusts produced by the national meteorological agency MeteoSwiss. We couple this hazard information with a spatially explicit impact model (CLIMADA) for building damages due to winter windstorms. Each day, the impact forecasting system publishes a probabilistic forecast of the expected building damages on a spatial grid.

This system produces promising results for major historical storms when compared to aggregated daily building insurance claims data from a public building insurer of the canton of Zurich. The daily impact forecasts were qualitatively categorized as (1) successful (2) miss or (3) false alarm. The impacts of windstorm Burglind-Eleanor and five other winter windstorms were forecasted reasonably well, with four successful forecasts, one miss and one false alarm.

 The building damage due to smaller storm extremes was not as successfully forecasted. Thunderstorms are not as well forecasted with 2 days’ lead time and as a result the impact forecasting system produces more misses and false alarms outside the winter storm season. For the Alpine-specific southerly Foehn winds, the impact forecasts produce many false alarms, probably caused by an overestimation of wind gusts in the weather forecast.

The forecasting system can be used to improve weather warnings and allocate resources and staff in the claims handling process of building insurances. This will help to improve recovery time and costs to institutions and individuals. The open-source code and open meteorological data makes this implementation transferable to other hazard types and other geographical regions.
3D basin and petroleum system modelling in the North Sea Central Graben - a Dutch, German, Danish cross-border study
Authors: Lutz Rüdiger , Nelskamp Susanne , Mathiesen Anders , Schovsbo Niels Hemmingsen , Ladage Stefan , Britze Peter
Published: March 2021

A Geological Analysis and Resource Assessment of selected Hydrocarbon Systems (GARAH) is carried out as part of the overarching GeoERA project. Here, we report results on the first public 3D basin and petroleum system model developed in a cross-border area of the Dutch, Danish and German North Sea Central Graben. This pilot study reconstructs the thermal history, maturity and petroleum generation of potential Lower, Middle and Upper Jurassic source rocks and assesses potential unconventional resources in a first phase. The 3D pilot study incorporates new aggregated and combined layers of the three countries. Results of the study feed back into the 3DGEO-EU project of GeoERA.

Eight key horizons covering the whole German Central Graben and parts of the Dutch and Danish North Sea Central Graben were selected for building the stratigraphic and geological framework of the 3D basin and petroleum system model. The model includes depth and thickness maps of important stratigraphic units as well as the main salt structures. Petrophysical parameters, generalized facies information and organic geochemical data from well reports are assigned to the different key geological layers. Further, the model is calibrated with temperature and maturity data from selected offshore wells as well as from publications. The time span from the Late Permian to the Present is represented by the model, including the most important erosional phases related to large-scale tectonic events during the Late Jurassic to Late Cretaceous. Additionally, salt movement through time expressed as diapirs and pillows is considered within the 3D basin and petroleum system model. Simulations depict that unconventional petroleum resources (oil and natural gas) are present in varying amounts in the source rocks across all three countries.

This is a part of an ongoing EU Horizon 2020 GeoERA project (The GARAH, H2020 grant #731166 lead by GEUS).
Double-diffusive depletion of layers in hydrothermal systems
Authors: Le Reun Thomas , Hewitt Duncan
Published: March 2021

In hydrothermal systems, the circulation of water through the porous matrix is strongly influenced by the joint effects of heat and salinity. Because of phase separation, layers of different salinities and temperature are thought to form, but their stability or their typical lifetime remains unclear. Moreover, the dynamics of heat transport across such a layered system is considerably enriched by double diffusive effects due to the slower diffusion of salinity relative to heat. Here, we study numerically the time evolution of an ideal two-layer configuration where a heavy layer of warm and salty water is overlain by a light layer of cold and fresh water. Thermal convection quickly develops in each layer and maintains a thin diffusive interface between the layers. There is long-standing controversy on the temporal evolution of such a system. Although Griffiths (1981) found experimentally that the sharp interface seemed to persist indefinitely, Schoofs & Hansen (2000) reported via numerical simulations systematic depletion and vanishing of the layers. We resolve this apparently inconsistency. In our simulations, we find systematic depletion of the two-layer initial condition in all cases. However, the timescale over which it occurs depends strongly on the ratio between salinity and temperature contributions to density. When salinity is weakly stabilising, thermal convection and layers are maintained over (very long) diffusive timescales. When salt is strongly stabilising, however, convection becomes quiescent over much shorter times and the sharp interface between layers is quickly diffused away. We determine scalings on the lifetime of the layers in both regimes as a function of the governing parameters.
First results after the deployment of a subsea geodetic monitoring system
Authors: Adam Pierre-François , Olivier Nathalie , Jaouen David
Published: March 2021

Geodetic networks at sea are necessary to monitor active faults and the long term displacement of tectonic plates. iXblue has developed a new integrated subsea monitoring system: Canopus

The Canopus transponders are enable to regularly measure precisely the distance between the transponders that are in acoustic line of sight. The measurement are stored in a memory inside each beacon and can be collected from surface using acoustic modem. In collaboration with the IUEM, and in the framework of ERC Focus project, 8 Canopus beacons were deployed at each side of the North Alfeo Fault in Sicilia for a  4 years monitoring program. To prepare the deployment, a first experiment took place in Brest Bay in July 2019, and a second one in La Ciotat Bay in September 2020. Thanks to Delph subsea positioning software, simulations enable to confirm acoustic line of sight between beacons considering the local bathymetry, the sound velocity profile and the height of the transponders above the seabed. The final deployment took place in October 2020.  We present here the series of test and  simulations conducted before the final deployment and the first results after deployment.
The hemispheric asymmetry of ionospheric lunitidal signatures during Sudden Stratospheric Warmings in the eastern Asian and American sectors
Authors: Liu Jing , Zhang Donghe , Goncharenko Larisa , Zhang Shun-Rong , He Maosheng , Hao Yongqiang , Xiao Zuo
Published: March 2021

During Sudden Stratospheric Warming events, the ionosphere exhibits phase-shifted semi-diurnal perturbations, which are typically attributed to vertical coupling associated with the semi-diurnal lunar tide (M2). Our understanding of ionospheric responses to M2 is limited. This study focuses on fundamental vertical coupling processes associated with the latitudinal extent and hemispheric asymmetry of ionospheric M2 signatures, using total electron content data from the eastern Asian and American sectors. Our results illustrate that the asymmetry maximizes at around 15°N and 20°S magnetic latitudes. In the southern hemisphere, the M2-like signatures extend deep into midlatitude and, in the American sector, encounter the Weddell Sea Anomaly. The M2 amplitude is larger in the northern hemisphere and such asymmetry is more distinct in the eastern Asian sector. The hemispheric asymmetry of M2 signatures in the low latitude can be primarily explained by the trans-equatorial wind modulation of the equatorial plasma fountain. Other physical processes could also be relevant, including hemispheric asymmetry of the M2 below the F region, the ambient thermospheric composition and ionospheric plasma distribution, and the geomagnetic field configuration.
Virtual user engagement methods for working with stakeholders in China 
Authors: Oakes Rosie , New Stacey , Weeks Jennifer , Golding Nicola , Hewitt Chris , Dunbar Tyrone
Published: March 2021

 

Climate services provide information to help better manage climate-related risks and opportunities in different sectors around the world. This requires work at the interface between scientific research and decision-making. Studies have found that climate services are most effective when they are co-developed and co-produced with the intended users of the services. To achieve this, climate service developments often involve scientists engaging with users and potential users, which traditionally has been most productive face-to-face, at least in the early stages of engagement and co-development to build relationships.  

In March 2020, the COVID-19 pandemic dramatically restricted face-to-face engagement, particularly for international activities. Climate service providers and users had to suddenly adapt and find methods to engage with each other virtually. Here we discuss the software and methods that are being used to ensure that provider-user engagement could continue, despite international travel restrictions, with a specific focus on working with users in China as part of the Climate Science for Services Partnership China project; a collaboration between the UK Met Office and other UK partners, the China Meteorological Administration, and the Institute of Atmospheric Physics. Using examples from work on food security with the agriculture sector in Northeast China, we will showcase different climate service prototype products, such as brochures, information packs, and comic book storylines which are helping us to engage with and understand the requirements of multiple audiences despite the lack of in-person engagement.  

Through this work, we have discovered additional benefits to virtual engagement, such as more frequent interactions with users, the ability to involve participants who wouldn’t usually be able to travel to attend events, and new metrics for evaluating climate services. These benefits will likely make virtual provider-user engagement a more common tool for developing and refining climate services with international partners in the future. We hope that the tools and methods presented here will help other climate service providers to conduct productive virtual provider-user engagement in the future, both in China and in other countries around the world. 
Copernicus satellites for supporting irrigation and water management in Australia: the COALA H2020 Project.
Authors: D Urso Guido , De Michele Carlo , Francesco Vuolo , Alfonso Calera , Anna Osann , Ryu Dongryeol , Graciela Metternicht
Published: March 2021

COALA is a project funded by the Horizon 2020 program of the European Union with the aim of developing Copernicus Earth Observation-based information services for irrigation and nutrient management in Australia, building on consolidated experience of past EU projects and existing operational irrigation advisory services. Earth Observation-based services can provide “diagnostic” data and information relevant for integrated input management of irrigation water and nutrients, from subplot level to irrigation scheme or river basin levels.

COALA, started on January 2020, is developing Copernicus-based information service for the Australian agricultural systems, based on strong collaboration with Academic Australian institutions and business players. COALA services will provide to farmers, irrigation organisation and basin authorities information about crops development, water and nutrient status, irrigated areas by means of innovative algorithms based on Sentinel Earth Observation data, which will be accessed by means of the new cloud platforms (DIAS) of Copernicus. In-situ and other source of data, such as ground soil moisture probes, meteorological stations and Numerical Weather Prediction models, will be used to improve the information provided to the final users.

The advancements beyond the state of art of COALA methodologies for managing irrigation are:

COALA will demonstrate that Copernicus data and new DIAS infrastructure can greatly improve the availability of a multi-scale information product shared by the different levels of users. The innovative approach achieves a "converging loop procedure" between water authority, irrigation infrastructure operation and farmers, enabling transparency in all the decision taken at all levels and improving the accuracy of estimation of actual water use.

https://www.coalaproject.eu/
Practical recommendations on how to combat discriminatory work environments in the geosciences
Authors: Popp Andrea L. , Hall Caitlyn A. , Yilmaz Yeliz A.
Published: March 2021

Even as discussions about the need for diverse, equal, and inclusive work environments have increased in recent years, discriminatory and hostile work climates are sadly still widespread within academia. Discriminatory and hostile working conditions negatively affect science and scientists at the individual, community, institutional, and societal levels, ultimately causing researchers mental health issues and hampering scientific progress. Those most affected by abusive research environments are early-career scientists of underprivileged, historically oppressed, and underrepresented groups. Thus, one step to increase diversity and equality within geosciences is to combat discriminatory work environments. While the burden of addressing hostile working conditions should not be on those experiencing bullying and discrimination, guidance and support are needed until we see real systemic change. To help make a change, we provide ten concrete strategies for all scientists experiencing any form of discrimination to overcome an unhealthy research environment (Popp et al., 2020).

 

References

Popp, A.L., Hall, C.A. and Yilmaz, Y.A. (2020) How to combat bullying and discrimination in the geosciences, Eos, 101, https://doi.org/10.1029/2020EO151914
Seasonality of Polar Warming in Climates with Very High Carbon Dioxide.
Authors: Henry Matthew , Vallis Geoffrey
Published: March 2021

Observations of warm past climates and projections of future climate change show that the Arctic warms more than the global mean, particularly during winter months. Past warm climates such as the early Eocene had above-freezing Arctic continental temperatures year-round. In this work, we show that an enhanced increase of Arctic continental winter temperatures with increased greenhouse gases is a robust consequence of the smaller surface heat capacity of land (compared to ocean), without recourse to other processes or feedbacks. We use a General Circulation Model (GCM) with no clouds or sea ice and a simple representation of land. The equator-to-pole surface temperature gradient falls with increasing CO2, but this is only a near-surface phenomenon and occurs with little change in total meridional heat transport. The high-latitude land has about twice as much warming in winter than in summer, whereas high-latitude ocean has very little seasonality in warming. A surface energy balance model shows how the combination of the smaller surface heat capacity of land and the nonlinearity of the temperature dependence of surface longwave emission gives rise to the seasonality of land surface temperature change. The atmospheric temperature change is surface-enhanced in winter as the atmosphere is near radiative-advective equilibrium, but more vertically homogeneous in summer as the Arctic land gets warm enough to trigger convection. While changes in clouds, sea ice and ocean heat transport undoubtedly play a role in high latitude warming, these results show that surface-enhanced atmospheric temperature change and enhanced land surface temperature change in winter can happen in their absence for very basic and robust reasons.
Minerals of Bolshoi Semiachik geothermal fields (Central Kamchatka, Russia)
Authors: Zhitova Elena , Ismagilova Rezeda , Sergeeva Anastasia , Nazarova Maria , Nuzhdaev Anton , Kuznetsov Ruslan , Bolshakov Ilya , Bukhanova Daria
Published: March 2021

The volcanic complex Bolshoi Semiachik is characterized by intensive hydrothermal activity which is expressed by presence of thermal fields with gas-steam jets (T up to ~ 140 ºC), boiling pots (T up to ~ 100 ºC), warm lakes (T up to ~ 90 ºC) and ground (T up to ~ 97 ºC) . The circulating hydrothermal solution is rich in ammonium, sulfate and locally in carbonate. To date, little is known about surface mineralogy that occurs at the geothermal fields of the volcanic complex Bolshoi Semiachik. The major geological expeditions were carried out there in the 1960`s, and there was also some additional research carried out in the 1980`s. The study of minerals occurring at the surface of geothermal fields is relevant for planetary science since similar minerals are suggested for Mars and Europa (Jupiter moon) and geochemistry since such environments of mineral formation are very specific.

In the summer 2020 the expedition of the Institute of volcanology and seismology has been organized in order to monitor thermal fields and to conduct mineral and water samples for study. Here we report the first data on mineral identification of processed samples (at about 50). At that moment, minerals have been identified by powder X-ray diffraction and electron-microprobe analyses.

The surface of Bolshoi Semiachik geothermal fields is covered by clay minerals with montmorillonite that is rich in disseminated pyrite being the most abundant. Among salt minerals the common phases are sulfates: halotrichite-, copiapite and voltaite-group minerals, alunogen, gypsum and native sulphur. The SiO2 polymorphs: tridymite, cristobalite are also found at the geothermal field surface. In the zone called Central Crater chalcantite has been found in association with rhomboclase and tridymite. Some samples with zeolite-group mineral - laumontite were also found, which at the moment is identified less reliably. The central (high temperature) part of deposits around steam-gas jet is composed of dickite in association with sulphur and quartz covered by alunogen and halotrichite efflorescent. The rim (at about 1 meter from the center) is composed of smectites, marcasite and natroalunite. This zonation is likely caused by pH which is lower at the central part where the steam unloads and increases at the peripheral area around the steam-gas jet.

Acknowledgment. The study has been supported by RFBR project # 20-35-70008. We are grateful to Volcanoes of Kamchatka for letting us to conduct the field works at Bolshoi Semiachik thermal fields. Experimental works on mineral identification have been carried out using Analytical Centre of IViS and Research Park of SPbU.
Foreshocks of the terrestrial planets: Simulations of kinetic effects
Authors: Kallio Esa , Jarvinen Riku , Gupta Shashikant , Pulkkinen Tuija
Published: March 2021

Planetary foreshocks and magnetosheaths are regions which include many small-scale kinetic processes. Therefore, terrestrial planets Mercury, Venus, Earth and Mars provide interesting laboratories to investigate how the kinetic effects depend on the properties of the solar wind and on the properties of the planet.

The kinetic effects can be investigated with a 3D hybrid model where ions are modelled as particles accelerated by the Lorentz force. Recent studies based on our parallel hybrid model have shown that the simulation has an adequate spatial resolution to investigate, in detail, the ion 3D velocity distributions and the properties of the ULF waves at the foreshocks of Mercury, Venus and Mars.  

In this presentation, we focus on the simulated 3D ion velocity distributions at various sites around terrestrial planetary bodies and discuss their role near the planets, especially at the foreshocks. We also introduce methods to automatically analyze basic properties of the ion velocity distributions in the simulation.
 Weather regimes in South East Asia: connections with synoptic phenomena and high impact weather
Authors: Howard Emma , Gonzalez Paula , Thomas Simon , Frame Thomas , Martinez-Alvarado Oscar , Methven John , Woolnough Steven
Published: March 2021

 

A tiered set of weather regimes describing variability in 850 hPa winds in South East Asia (SEA) is presented and compared to a corresponding non-tiered set of weather regimes. The tiered regimes are calculated in two parts: the first tier computed by applying EOF/K-means clustering on a planetary scale domain which partitioning seasonal variation and ENSO, and the second tier obtained by EOF/K-means clustering on a smaller SE Asia regional domain, partitioning the synoptic variability within each of the first tier regimes. This identifies synoptic weather phenomena with multi-day persistence. In contrast, the un-tiered (“flat”) clustering approach uses a standard EOF/K-means classification in the regional domain without conditional dependence on large-scale, with the number of regimes set to match the tiered regimes.  

These regimes are used to study the likelihood of extreme precipitation depending on synoptic circulation. We consider the conditional probability depending on regime type of synoptic weather events including cold surges, phases of the MJO and BSISO, tropical cyclones, Borneo Vortices and equatorial waves. We then study the regime-conditioned probability of high percentile TRMM precipitation. We find that a perfect regime forecast would have greater skill than the GloSEA5 precipitation forecast for lead times longer than approximately one week. The tiered regimes distinguish a greater fraction of considered modes of variability, while the flat regimes better distinguish the precipitation variability.  

The predictability of these regimes will be discussed in a separate presentation, titled “Weather regimes in South East Asia: Sub-seasonal predictability of the regimes and the associated high impact weather” and presented by Paula Gonzalez. 
Estimation of earthquakes location errors distribution for LUMINEOS local seismic network in Poland. 
Authors: Kokowski Jakub , Rudziński Łukasz
Published: March 2021

Estimation of hypocenter location errors  is not a simple task. These errors are influenced by many factors. The most important are: the quality of velocity model, the configuration of stations in the observation network and the noise level recorded at stations. While the network configuration affects the error distribution in a deterministic manner, the noise level is largely random. It means that the uncertainties cannot be determined in a deterministic way and only statistical approach can be used. There are several methods for estimating location errors for particular seismic network. Some techniques use synthetic seismograms to calculate the detection range related to each station. However, this approach requires very precise knowledge of the geological model, which is not always possible. Instead, in this work we present a different approach, which uses only phase data for events included in the catalog. In this method, the detection range for each station is estimated using the detection probability (Schorlemmer & Woessner, 2008) used for both P- and S- waves first arrivals. The usefulness of this approach is discussed assuming the shape of  LUMINEOS seismic network which operates in the Legnica-Głogów Copper District (LGCD), Poland. In the LGCD region seismic activity is related to three deep underground copper mines. Every year thousand of seismic events with magnitudes up to M4.0 are registered here. Some of them are followed by tragic mining collapses and are widely felt by local residents.
Arable soil surface status as a factor affecting the quality of soil properties detection based on remote or proximal sensing technologies
Authors: Prudnikova Elena , Savin Igor , Vindeker Gretelerika
Published: March 2021

Due to short wavelengths, optical remote sensing data provides information about the properties of very thin soil surface layer. This is especially crucial for arable soils as their surface experiences intense impact of agricultural practices and natural conditions. In temperate zone atmospheric precipitation is one of the main natural factors affecting the surface state of arable soils. It causes the breakdown of soil surface aggregates and the redistribution of formed soil material resulting in surface sealing and the formation of soil crust.

We studied the properties of soil crust and its impact on the detection of soil properties on arable soils of European part of Russia.

Our research showed that the properties of soil surface crust (texture, mineralogical composition, organic matter content, content of microelements, spectral reflectance) differed from the properties of the rest of arable horizon. That discrepancy negatively impacted the performance and reproducibility of the models developed for the detection of arable soil properties and their monitoring on the basis of optical remote sensing data.

We found that the performance of the models for the detection of soil fertility indicators based on Sentinel-2 data varied depending on the acquisition date. Optimal dates were different for different fertility indicators. Introduction of information on soil surface state (% of crust and shadows/cracks) at different acquisition dates as predictors in the models developed based on Sentinel-2 data allowed improving their performance and stability.

Therefore, soil surface state is an important factor which should be considered when developing models for the detection and monitoring of arable soil properties based on optical remote sensing data or proximal sensing of soil surface. Usage of laboratory soil spectra libraries instead of field spectral data leads to less precise prediction models.

The research was supported by the Ministry of science and higher education of Russia (agreement No 075-15-2020-909), and RUDN University Strategic Academic Leadership Program.
History Matching for parameter tuning: the Lorenz96 model as a case study
Authors: Lguensat Redouane , Deshayes Julie , Balaji Venkatramani
Published: March 2021

A major cause of earth system model discrepancies result from processes that are missed or are incorrectly represented in the model's equations. Despite the increasing number of collected observations, reducing parametric uncertainties is still an enourmous challenge.

The process of relying on experience and intuition to find good sets of parameters, commonly referred to as "parameter tuning" keeps having a central role in the roadmaps followed by dozens of modeling groups involved in community efforts such as the Coupled Model Intercomparison Project (CMIP). 

In this work, we study a tool from the Uncertainty Quantification community that started recently to draw attention in climate modeling: History Matching also referred to as "Iterative Refocussing".

The core idea of History Matching is to run several simulations with different set of parameters and then use observed data to rule-out any parameter settings which are "implausible". Since climate simulation models are computationally heavy and do not allow testing every possible parameter setting, we employ an emulator that can be a cheap and accurate replacement. Here a machine learning algorithm, namely, Gaussian Process Regression is used for the emulating step. History Matching is then a good example where the recent advances in machine learning can be of high interest to climate modeling.

We investigate History Matching on a toy model: the two-layer Lorenz96, and share our findings about the challenges and opportunities of using this technique. We also discuss the use of this technique for realistic ocean models such as NEMO.
Structural Controls on Himalayan Glacial Lake Expansion
Authors: Peacey Matthew , Holt Tom , Glasser Neil , Reynolds John
Published: March 2021

As glaciers in the Himalaya have lost mass, their proglacial lakes have expanded. Despite increasing interest in hazard assessment and mitigation of Glacial Lake Outburst Floods (GLOFs) over more than the last two decades, the role of glacier structures in controlling patterns and rates of glacier recession, and subsequently of lake expansion, have not yet been investigated in detail. This study aims to identify and map glacier structures over a 20-year period and investigate their significance in ice front recession. Four glacial lakes and their associated debris-covered glaciers have been examined in the Everest Region of Nepal and China: Imja Tsho, Tsho Rolpa, Lumdin Tsho, and Dang Pu Tsho. Lake area was mapped between 2000 and 2020 using images acquired from Landsat 5/7/8 and Sentinel 2. Discrete glacier flow units were identified and specific structures were digitised using the finest-resolution panchromatic bands. We reveal a distinct pattern of transverse features across each glacier that can be related to ice frontal position through time. While this is not the only controlling factor contributing towards ice front recession from lake-terminating glaciers in the Himalaya, it is clear that pre-existing structures influence the ice front shape and are involved in ice front deterioration. These observations could be used to indicate future ice front positions and behaviour, and rates of glacier recession and of lake expansion.  This would also enable GLOF hazard assessments to include more detailed glaciological factors and help in the recognition of such legacy structures in the behaviour of stagnant debris-covered ice masses that are part of terminal moraine complexes.
ALARM  Project -multi-hAzard monitoring andearLy wARning systeM-
Authors: Soler Manuel , Brenot Hugues , Biondi Riccardo , Bannister Daniel , Grewe Volker , Bolic Tanjia , García-Heras Javier
Published: March 2021

We present the SESAR funded project ALARM. The overall objective of ALARM is to develop a prototype global multi-hazard monitoring and Early Warning System for different hazards affecting aviation. Continuous global Earth observations from satellite, ground-based systems, and atmospheric forecasts will be used to feed models capable of observing and predicting (nowcasting/forecasting) the displacement of particles in suspension and gas derived from natural hazards (volcanic ash and SO2, dust clouds from sandstorms, and smoke from a forest fire); severe weather situations such as deep convection and extreme weather; exposure to increased levels of solar radiation during flight; and environmental hotspots potentially contributing to global warming in a large extent. Specifically, the aim is to enhance situational awareness of all stakeholders in case of multiple hazard crisis by facilitating the transfer of required relevant information to end-users, presenting such information in a user-friendly manner to ATM stakeholders. In summary, anticipating severe hazards and fostering better decision-making.

ALARM will enhance an existing alert system –– with additional observations coming from geostationary satellites, improving the capabilities of observing natural hazards such as volcanic ash, SO2 plumes, sandstorms, and forest fire.

ALARM will tailor alert products (based on observations from satellites) of volcanic ash, SO2 plumes, sandstorms, and forest fire to aviation stakeholders, including its severity, geographical location, and altitude.

ALARM will develop nowcasting [up to 2 hours] and short-term forecasting [up to 6 hours] of SO2 plumes at a regional scale.

ALARM will develop nowcasting [up to 2 hours] and short-term forecasting [up to 6 hours] of severe thunderstorms at a local scale (airport).

ALARM will develop short-term forecasting [up to 6 hours] and medium-term forecasting [up to 48 hours] of climatic hotspots at a European scale.

ALARM will draft the requirements of all these alert products to be included in the SWIM Yellow profile.

 
Long-term monitoring of vegetation and hydrology in headwater catchments and the difficulties to embrace data-oriented and process-oriented approaches
Authors: Hauhs Michael , Meesenburg Henning , Lange Holger
Published: March 2021

In the Bramke valley (western Harz mountains, North Germany), three forested headwater catchments have been monitored since decades. A broad range of observables relevant to forestry, hydrology, hydrochemistry and ecosystem research allows to compare different approaches to environmental monitoring; each of them has its own set of relevant observables. The basic temporal resolution is daily for hydrometeorology and bi-weekly for streamwater chemistry; standing biomass of the Norway spruce stands is measured every couple of years.

Tree growth (site index) has changed between and within rotation periods (of up to 129 years); changes in soil nutrient pools are typical variables used to explain this nonstationary forest growth when the spatial-temporal scales match. In hydrology, transport mechanisms of water and solutes through catchment soils are used to model and predict runoff and its chemistry. Given the homogeneity of the area in terms of geology, soils and topography as well as climate, differences between the catchments in the Bramke valley are mostly related to forestry variables. The catchments exhibit long-term changes and spatial gradients related to atmospheric deposition, management and changing climate. After providing a short multivariate summary of the dataset, we present several nonlinear metrics suitable to detect and quantify subtle changes and to describe different behavior, both between different variables from the same catchment, as well as for the same variable across catchments.

Soil water potential and solution chemistry are further links between forestry and hydrology. However, at Lange Bramke, similar to other catchment studies, the evaluation of these data sets has not converged to a consistent, realistic model at the catchment scale. We hypothesize that this lack of model integration is due to theoretical rather than technical limits. A possible representation of these limits might be phrased in a category theory approach.
Observed and CMIP-simulated links between North Atlantic climatological winter jet latitude and inter-annual to decadal ocean-atmosphere coupling
Authors: Bracegirdle Thomas , Lu Hua , Robson Jon
Published: March 2021

Decadal variability in indices of North Atlantic (NA) atmospheric circulation plays a major role in changing climate over western Europe. However, reproducing characteristics of this variability in climate models presents a major challenge. Climate models broadly exhibit weaker-than-observed multi-decadal variability in atmospheric circulation indices. A prominent explanation for this is that model-simulated links between anomalous sea-surface temperatures (SSTs) and atmospheric variability are too weak. The dominant mode of basin-wide NA SST variability is Atlantic multi-decadal variability (AMV), which on multi-decadal timescales is expressed more strongly over the NA sub-polar gyre (SPG). SSTs over the SPG region (SSTSPG) are therefore the main focus here.

Studies to date have shown that variability in the North Atlantic Oscillation (NAO) exhibits strongest correlations with AMV indices in late winter, but the reasons for this are not clear. Here we show that this stronger late-winter correlation is particularly clear for SSTSPG and coincides with a climatological equatorward shift of the eddy-driven NA westerly jet from early-to-late winter. To help gain dynamical insight, indices of eddy-driven jet latitude (JLI) and speed (JSI) were correlated with SSTSPG and it was found that they exhibit more pronounced early-to-late winter shifts in correlations than for the NAO; In particular,  correlations strengthen from early-to-late winter for JLI while weaken for JSI. Our results suggest that the jet-SSTSPG linkages progress through winter from JSI dominant in early winter to JLI dominant in late winter.

CMIP5 and CMIP6 models were then evaluated for representation of these observed characteristics in ocean-atmosphere linkages. Consistent with the observed sub-seasonal links between climatological jet latitude and atmosphere-ocean correlation strength, CMIP models with larger equatorward jet biases exhibit weaker JSI-SSTSPG correlations and stronger JLI-SSTSPG correlations. A pronounced early-winter equatorward bias in jet latitude in CMIP models could partially explain the weaker-than observed linkage between SSTs and atmospheric variability.  
Reduced global warming from CMIP6 projections when weighting models by performance and independence
Authors: Brunner Lukas , Pendergrass Angeline G. , Lehner Flavio , Merrifield Anna L. , Lorenz Ruth , Knutti Reto
Published: March 2021

To extract reliable estimates of future warming and related uncertainties from multi model ensembles such as CMIP6, the spread in their projections is often translated into probabilistic estimates such as the mean and likely range. Here, we use a model weighting approach, which accounts for the CMIP6 models' historical performance as well as their interdependence, to calculate constrained distributions of global mean temperature change.

We investigate the skill of our approach in a perfect model test framework, where we use previous-generation CMIP5 models as pseudo-observations in the historical period. The performance of the distribution weighted in the abovementioned manner with respect to matching the pseudo-observations in the future is then evaluated, and we find a mean increase in skill of about 17 % compared with the unweighted distribution. In addition, we show that our independence metric correctly clusters models known to be similar based on a CMIP6 “family tree”, which enables the application of a weighting based on the degree of inter-model dependence.

We then apply the weighting approach, based on two observational estimates, to constrain CMIP6 projections. Our results show a reduction in the projected mean warmingbecause some CMIP6 models with high future warming receive systematically lower performance weights. The mean of end-of-century warming (2081–2100 relative to 1995–2014) for SSP5-8.5 with weighting is 3.7°C, compared with 4.1°C without weighting; the likely (66%) uncertainty range is 3.1 to 4.6°C, which equates to a 13 % decrease in spread.
Spectral induced polarization of the plant root: Experiments and numerical modeling.
Authors: Tsukanov Kuzma , Schwartz Nimrod
Published: March 2021

Exploration of plant roots and monitoring their conditions during growth is of great importance. A promising method for the non-invasive investigation of plant roots is spectral induced polarization (SIP). To enhance understanding of the mechanism controlling the plant root’s induced polarization response, we have conducted a series of experiments and constructed a physical-based numerical model. We measured the SIP signal of wheat root grown in the nutrient solution. The experiments have demonstrated a relationship between the SIP parameters (chargeability and relaxation time) and the root biomass and surface area. Monitoring the SIP response of roots poisoned by cyanide has revealed that the root polarization source is the cell membrane potential. In addition, we modeled plant root as a collection of 2-dimensional individual cells surrounded by an electrolyte. The SIP signal was calculated based on the numerical solution of the Poisson-Nernst-Planck equation. The model has supported the experimental results with the correlation between the magnitude of polarization and the root surface area. According to the model, the root polarization magnitude is related to the root’s external surface area. The polarization length scale is the root’s diameter, not the cell diameter. Based on these results and data from the literature, we suggest that at the low-frequency range associated with the SIP method, passing the current through the plant results in polarization of the individual cells, a relatively high polarization and relaxation time that is related to the cell length. On the other hand, injecting current to the growing medium results in the polarization of the external surface area of the root and polarization length scale related to the root diameter.
Accuracy assessment of the joint CloudSat-CALIPSO global cloud amount based on the bootstrap confidence intervals
Authors: Kotarba Andrzej , Solecki Mateusz
Published: March 2021

Vertically-resolved cloud amount is essential for understanding the Earth’s radiation budget. Joint CloudSat-CALIPSO, lidar-radar cloud climatology remains the only dataset providing such information globally. However, a specific sampling scheme (pencil-like swath, 16-day revisit) introduces an uncertainty to CloudSat-CALIPSO cloud amounts. In the research we assess those uncertainties in terms of a bootstrap confidence intervals. Five years (2006-2011) of the 2B-GEOPROF-LIDAR (version P2_R05) cloud product was examined, accounting for  typical spatial resolutions of a global grids (1.0°, 2.5°, 5.0°, 10.0°), four confidence levels of confidence interval (0.85, 0.90, 0.95, 0.99), and three time scales of mean cloud amount (annual, seasonal, monthly). Results proved that cloud amount accuracy of 1%, or 5%, is not achievable with the dataset, assuming a 5-year mean cloud amount, high (>0.95) confidence level, and fine spatial resolution (1º–2.5º). The 1% requirement was only met by ~6.5% of atmospheric volumes at 1º and 2.5º, while more tolerant criterion (5%) was met by 22.5% volumes at 1º, or 48.9% at 2.5º resolution. In order to have at least 99% of volumes meeting an accuracy criterion, the criterion itself would have to be lowered to ~20% for 1º data, or to ~8% for 2.5º data. Study also quantified the relation between confidence interval width, and spatial resolution, confidence level, number of observations. Cloud regime (mean cloud amount, and standard deviation of cloud amount) was found the most important factor impacting the width of confidence interval. The research has been funded by the National Science Institute of Poland grant no. UMO-2017/25/B/ST10/01787. This research has been supported in part by PL-Grid Infrastructure (a computing resources).
Return period analysis to assess the long-term impact of climate change on olive sector in Andalusia, Spain - results from the Med-Gold project
Authors: Gratsea Myrto , Varotsos Konstantinos , Lopez-Nevado Javier , Lopez-Feria Silvia , Giannakopoulos Christos
Published: March 2021

Return period analysis to assess the long-term impact of climate change on olive sector in Andalusia, Spain - results from the Med-Gold project

M. Gratsea1, K. V. Varotsos1, J. López-Nevado2, S. López-Feria2, C. Giannakopoulos1

1 Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Greece

2 DCOOP Sociedad Cooperativa, Andalusia, Spain

 Abstract

Med-Gold project, aims to develop climate services for olive, grape and durum wheat crops, which are the hallmarks of the Mediterranean food system. The generated climate related information at different timescales will be exploited by the end-users for operational decision-making. The objective of this study is to employ the return period method for communicating the effect of climate change on the olive crops in the long-term in Andalusia, which is one of the most important olive growing areas worldwide. Therefore, return periods of bad years in terms of olive yield and olive fly risk are being calculated for the reference period 1971-2000 and for the near (2031-2060) and distant future (2071-2100) under the RCP4.5 and RCP8.5 emission scenarios using an ensemble of five bias-corrected Regional Climate Models. The identification of the bad years - and the corresponding thresholds - is based on observational data from five monitoring stations in Andalusia (Malaga, Granada, Sevilla, Cordoba and Jaen) and the role of certain meteorological parameters (precipitation, temperature, relative humidity) is investigated. The results indicate an overall tendency for increased occurrence probability of bad years in terms of yield due to future higher temperatures and decreased precipitation. The impact is more pronounced towards the end of the century and under the RCP8.5 future emission scenario.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776467.