bluuebunny/crossref_metadata_2025 huggingface dataset:
Considering local network characteristics and environmental conditions improves rainfall estimates from commercial microwave links in Sri Lanka
Authors: Walraven Bas , Overeem Aart , Leijnse Hidde , Coenders Miriam , Hut Rolf , van der Valk Luuk , Uijlenhoet Remko
Published: March 2022

To improve rainfall monitoring from Commercial Microwave Links (CMLs) in a (sub)tropical climate, we adjust several parameters in the open-source R package RAINLINK that is used to retrieve rainfall rates from signal attenuation in cellular telecommunication networks.

These parameters related to local CML network characteristics (lower frequencies, longer link paths, quasi-linear k-R relation) and to environmental conditions (large spatial rainfall variability, convective rainfall) are considered to improve rainfall estimations across Sri Lanka. The analysis is based on data from ~1100 link paths for a 3-4 month period. The resulting rainfall depth maps are validated with multiple rain gauges across Sri Lanka at the hourly and daily time scale, and compared with space-borne weather radar data. 

Until now, the majority of efforts to provide rainfall estimates from CMLs have focused on temperate climates, in Western Europe, where there generally is good coverage from weather radars and a fairly dense network of rain gauges. However, the greatest potential for this ‘opportunistic’ source of rainfall estimation lies in those regions that lack traditional surface rainfall observations, most notably low- to middle income countries, and mountainous areas, where rain gauges are scarce or poorly maintained, and weather radars are largely unavailable.

With this study we further highlight the potential for CMLs to provide high-resolution space-time rainfall observations in the tropics for use in a wide range of hydrometeorological applications, such as forecasting rainfall-induced natural hazards (flash floods, landslides) and validating satellite rainfall products.
Insights into the role of geology in human occupation strategies in Bronze Age Sardinia (Italy)
Authors: Mariani Guido Stefano , Brandolini Filippo , Melis Rita Teresa
Published: March 2022

The geological substrate and its landforms, as main providers of natural resources, have a clear influence on landscape management practices The landscape evolution of the island of Sardinia (Italy) during the Holocene has strongly influenced the populations settled there, especially during the Bronze Age. We constructed a map of the land units in the southwestern corner of Sardinia and compared them with the distribution of known Bronze Age megalithic towers called nuraghes. Our aim is to understand which factors represent relevant criteria for settlement and try to infer possible causes.

The vast majority of nuraghes are located in proximity to river networks at low and mid elevations. Most densely settled areas also show the highest landscape diversity with a variety of land units much higher than the rest of the territory. Another potential factor affecting the location choice for nuraghes is the presence of elevated outcrops, which provide the advantage of a raised position and of stable foundations. The interaction of human dispersal patterns with landscape features can provide useful information on the sustenance strategies of past communities. It can therefore be interesting to consider the combined effect of geodiversity and landscape diversity in order to build more accurate dispersal models.
Preliminary results of metal content analysis in the outdoor air of Berlin using an impactor prototype optimised for TXRF analysis
Authors: Crazzolara Claudio , Waldschläger Ulrich , Held Andreas
Published: March 2022

Air pollution is responsible for a major part of environmental-related health impacts on humans. Aerosol particles in the inhalable size range account for the largest contribution. To improve air quality with targeted measures, it is necessary to precisely identify and minimise the emission sources of airborne particles. Data with high temporal resolution on the size fractionated chemical composition is of great value in this context, as it allows conclusions to be drawn about the emission sources of the particles.

Conventionally conducted filter samplings with subsequent chemical analysis of the collected aerosol particles usually cannot provide high time resolution, as the analytical methods used so far require a minimum amount of sample material.

Here, the development of a measurement approach that analyses aerosol particles using Total Reflection X-ray Fluorescence (TXRF) is presented. TXRF analysis is based on the reflection of a shallow incident X-ray beam on a reflective sample carrier loaded with aerosol particles. A high detection sensitivity for elements of high atomic numbers with a minimum sample quantity required characterises this method.

Particle collection is conducted by means of an impactor optimised for the measurement geometry of the TXRF spectrometer. Aerosol size fractions are deposited directly on the TXRF sample carrier for subsequent analysis. TXRF analysis can be performed by a compact tabletop device, which is also portable for use in the field directly after particle collection.

The coupling of a commercially available cascade impactor with a TXRF spectrometer has shown a high potential of this method. We further improve this by developing a cascade impactor specifically optimised for a TXRF spectrometer, in order to achieve the lowest possible detection limits. In our contribution, we present first TXRF analysis results of particles collected from outdoor air in Berlin using a prototype cascade impactor and outline the advantages as well as the challenges of this analytical approach.
Results of the MOCAST+ study on a quantum gravimetry mission
Authors: Migliaccio Federica , Batsukh Khulan , Benciolini Giovanni Battista , Braitenberg Carla , Koç Öykü , Mottini Sergio , Pastorutti Alberto , Pivetta Tommaso , Reguzzoni Mirko , Rosi Gabriele , Rossi Lorenzo , Sorrentino Fiodor , Tino Guglielmo Maria , Vitti Alfonso
Published: March 2022

MOCAST+ (MOnitoring mass variations by Cold Atom Sensors and Time measures) is a recently concluded study funded by the Italian Space Agency (ASl) and jointly carried out by several Italian research groups, focusing on a gravimetry mission based on quantum technology.

In the past twenty years, space missions like GRACE and GRACE-FO have formed a well-organized user community tracking the Earth mass movement to study environmental changes on a global scale using data from satellite measurements. In fact, monitoring global parameters underlying climate change, water resources, flooding, melting of ice masses and the corresponding global sea level rise is of paramount importance, since remote sensing of the changes of the Earth gravitational field provides basic data on, e.g., geodynamics, earthquakes, hydrology or ice sheets changes.

Since classical sensors have reached a high level of maturity with a limited potential for further improvement, a large interest has developed in novel technologies based on quantum technologies and quantum sensing. These technologies promise to offer higher sensitivity and drift-free measurements, and higher absolute accuracy for terrestrial as well as space missions, thus giving direct access to more precise long-term measurements and comparisons.

Europe is at the forefront of quantum technologies, and activities towards the deployment of pathfinder quantum gravimetry mission within this decade are being funded at various levels. Looking at a time frame beyond the present decade, in the MOCAST+ study we have analyzed the performance of a quantum enhanced payload consisting of a Cold Atom Interferometer based on strontium atoms and acting as a gravity gradiometer, plus an optical frequency measurement using an ultra-stable laser, in order to also provide time measurements. The main goals of the study were to define the level of accuracy which can be expected from such a payload and the level of accuracy which is needed in order to detect and monitor phenomena identified in the Scientific Challenges of the ESA Living Planet Program, in particular Cryosphere, Ocean and Solid Earth.

We will present the results of the study in terms of proposed payload, mission profile and preliminary platform design, results of end-to-end simulations and assessment of the impact of the proposed mission for geophysical applications.
The effect of utilization of the Theistareykir (N-Iceland) high temperature field on the natural geothermal surface manifestations and groundwater composition
Authors: Galeczka Iwona , Óskarsson Finnbogi , Clark Deirdre , Kristinsson Sigurður Garðar , Ólafsson Magnús , Óladóttir Auður Agla , Ingimarsson Heimir , Nielsen Steinþór , Sigurðardóttir Ásgerður K.
Published: March 2022

The global framework of the Paris Agreement aims for rapid reduction of GHG emissions to keep the global average temperature below 2 °C above pre-industrial levels. Renewables including geothermal are crucial in transition from a current carbon intensive to carbon neutral or carbon negative energy sources. Although considered as green and sustainable, the subsurface pressure changes caused by thermal fluid extraction might affect the spatial distribution and content of surface manifestations, e.g., fumaroles and may disturb the groundwaters system in the area. As such monitoring of natural features and groundwaters during the geothermal utilization is crucial in the sustainable management of the power plant and it contributes to the understanding of the hydrothermal system through its production lifetime. The aim of this study is to assess the possible effect of the Theistareykir power plant operation on the fumaroles and groundwater chemical composition.

The deep exploration wells in Theistareykir drilled in 2002-2012 confirmed predicted downhole temperatures of >300 °C and high energy generation capacity of the field. The production drilling in 2016-2017 and construction of the power plant carried out in 2015-2017 resulted in a 45 MWe production unit that started commercial operation in 2017. In 2018 a second 45 MWe unit was added increasing the total power output to 90 MWe. Today 12 production and 2 reinjection wells are in use. The results of the continuous fumarole monitoring within the geothermal field since 2012, show no substantial differences in the gases’ concentrations. The current temperature of the reservoir based on the gas geothermometers is similar to the one obtained during the exploration stage (270-315 °C). The fumaroles located in the center and eastern parts of the production field show a continuous decrease in H2S and H2 since 2015, before commencement of the power plant. The concentrations of the elements of concern such as As, Al, Cu, Zn, Cd, Pb, Cr, Ni in groundwaters show no major variations since monitoring first began in 2011. Furthermore, they have not exceeded limits established by the Icelandic directive for surface waters to protect sensitive biota. Even though the absence of noticeable changes in the compositions of the fumaroles and groundwater indicate that the production that started in 2017/18 has currently not posed an environmental threat, observations made in the other production fields suggest that this can be expected in the future. 
Reservoir triggered seismicity in tectonically stable and seismically active areas of Vietnam
Authors: Lizurek Grzegorz , Leptokaropoulos Konstantinos , Staszek Monika , Nowaczyńska Izabela , Tymińska Anna
Published: March 2022

Water reservoirs play important role in energy production in Vietnam. Numerous dams were designed and built for hydropower plants and water storage during the wet season and its release during dry season. They were built in a different tectonic settings. We present our experience of several years of monitoring and research on two sites: first, tectonic active area of Lai Chau (North Vietnam) and relatively stable area of Song Tranh in Central Vietnam. We observed different seismicity patterns in this areas. Area of active tectonics in Lai Chau was less active in terms of reservoir triggering, while almost aseismic area of Song Tranh was highly active after reservoir impoundment. We proved, that this activity was related with seasonal water level changes in reservoir. Moreover, low water period during service works was proved to be more active and with significantly higher seismic hazard than during initial production regime and after the refilling. It suggests that decrease of water level and following pore-pressure change destabilize minor faults being closer to failure, than main faults in the area. We also found multiplet events triggered on minor normal faults in shallow depth despite the strike-slip regime of regional tectonic stress field. On the other hand in the active area of Lai Chau we observed triggering both on existing active strike-slip faults and minor normal fault discontinuities. However, the difference between seismic activity parameters before and after impoundment except spatial distribution directly after first filling didn’t differ substantially. We can conclude, that in stable tectonic setting triggering effect is clear and related with pore-pressure changes caused by reservoir water level fluctuations, which is main seismogenic factor. On the other hand in active seismic area reservoir water level fluctuation seems to be too small to significantly influence seismic activity in the long term.

This work was partially supported by the research project no. 2017/27/B/ST10/01267, funded by the National Science Centre, Poland under the agreement no. UMO-2017/27/B/ST10/01267 (GL and IN) and partially supported by the research project no. 2021/41/B/ST10/02618, funded by the National Science Centre, Poland under the agreement no. UMO-2021/41/B/ST10/02618 (GL and AT) and partially by National Statutory Activity of the Ministry of Education and Science of Poland No 3841/E-41/S/2022 (MS)
High Temperature ATES in combination with power-to-heat: maximizing renewable energy use for a local energy system
Authors: Beernink Stijn , van der Roest Els , van der Hoek Jan Peter , Hartog Niels , Bloemendal Martin
Published: March 2022

To reduce worldwide greenhouse gas (GHG) emissions, fossil fuels are being replaced by renewable energy in a rapid tempo. As a result, the energy system becomes more decentralized with e.g. PV systems as a source for local multi-energy systems, with aim to become as self-sustainable as possible. This is challenging because these systems often rely on an intermittent energy source (production mainly in summer), which is not aligned with energy demand (mainly in winter). One solution for this problem is the combination of power-to-heat (PtH) with High Temperature Aquifer Thermal Energy Storage (HT-ATES), which allows for flexible and effective utilisation and storage of available green electricity to match the availability and demand of sustainable electricity. Currently, insights in the practical potential of this solution and methods for effective integration of PtH and HT-ATES in multi-energy systems are lacking. Therefore, we assessed methods to improve the integration and control of a HT-ATES system and tested varying ways of integration for a local decentralized multi-energy system. To this end, we expanded and integrated a multi-energy system model with a numerical hydro-thermal model to dynamically simulate the functioning of the integrated HT-ATES. The impact of key design parameters (heat pump size, storage temperature, cut-off temperature) on overall energy performance and the effect of different methods for integration of the local energy system were simulated and analysed. 

Results show that the integration of HT-ATES with PtH allows for providing the local energy system with 100% of the yearly heat demand with a 25% smaller heat pump than without HT-ATES. Also, compared to Pth without storage, the yearly energy use pattern changes dramatically to match the availability of renewable electricity. An inventive mode of operation was designed which allows for lowering the threshold temperature of the HT-ATES by an innovative integration of the heat pump. This mode of operation increases the HT-ATES performance and decreases the overall costs of heat production. Overall, this study shows that the integration of HT-ATES in a multi-energy system is suitable to cost-effectively match annual heat demand and supply, and to increase local sustainable energy use. Solutions like these show high potential to decentralize energy production/use, to decrease pressure on the power grid and to increase total renewable energy use.
Calibrating the WSA velocity in EUHFORIA based on PSP observations
Authors: Samara Evangelia , Arge Charles N. , Pinto Rui F. , Poedts Stefaan , Magdalenic Jasmina , Rodriguez Luciano
Published: March 2022

Coronal models, usually extending between the solar photosphere and ~30 Rs, are an integral part of many space weather forecasting tools. They reconstruct the magnetic field in the solar corona and provide the necessary plasma conditions for initiating heliospheric models such as EUHFORIA or Enlil. A big gap in literature is identified when it comes to the validation of such models because of lack of observations, especially in situ. Nevertheless, the launch of the Parker Solar Probe (PSP) has provided, for the first time, in situ observations very close to the Sun that can help with the evaluation of such models. In this work, we aim to calibrate the Wang-Sheeley-Arge (WSA) semi-empirical formula used in EUHFORIA for the reconstruction of plasma and magnetic parameters at 0.1 AU. We exploit PSP in situ measurements between 0.1 – 0.4 AU obtained from the first 8 perihelia. We show how a parametric study of the WSA formula influences the velocity and density distributions very close to the Sun, how the modeled distributions are compared to PSP observations and present the relevant forecasting results at PSP and Earth.
Climate transitions during the Late Glacial and the Early Holocene reconstructed from moraine records in the Austrian Alps
Authors: Braumann Sandra M. , Schaefer Joerg M. , Neuhuber Stephanie , Fiebig Markus
Published: March 2022

Glaciers provide an excellent natural laboratory for reconstructing the climate of the past as they respond sensitively to climate oscillations with advance or retreat. Therefore, we study glacier systems and their behavior during the transition from colder to warmer climate episodes in glaciated valleys of the Silvretta Massif in the Austrian Alps.  

Using a combination of geomorphological mapping and beryllium-10 surface exposure dating, we reconstruct ice extents of the past and find that glaciers stabilized during the Pre-Bølling to Bølling transition (14.4 ± 1.0 ka, n=3), during the Younger Dryas (ca. 12.9-11.7 ka; n=7), and during the earliest Holocene (ca. 12-10 ka; n=2). The first, (pre)-Bølling age group indicates a stable ice margin that postdates the Gschnitz stadial (ca. 17-16 ka) and predates the Younger Dryas. It shows that local inner-alpine glaciers prevailed until the onset of the Bølling warm phase (ca. 14.6 ka) or possibly even into the Bølling. The second Younger Dryas age group captures the spatial and temporal fine structure of glacier retreat during the Egesen stadial prior to Holocene warming. It evidences ice surface lowering of several tens of meters throughout the Younger Dryas, which is indicative of milder climate conditions at the end of the stadial compared to its beginning. The third age group falls into a period of substantial warming, the Younger Dryas-Holocene transition. The deposition of moraines during a period of abrupt warming implies centennial-scale cold snaps that were probably caused by feedback in the climate system. An explanation proposed in the Younger Dryas-Holocene context is the deglaciation of ice sheets in the Northern hemisphere and resulting freshwater input into the Atlantic ocean, which in turn slowed down ocean circulations and thus reduced heat transport toward (Northern) Europe.

The new geochronologies synthesized with pre-existing moraine records from the Silvretta Massif show that the transition from glacial to interglacial climate conditions occurred within a few centuries and illustrate the sensitive response of Silvretta glaciers to abrupt warming events in the past. Our ice-margin reconstructions provide an example of the response of glaciers and the climate system in a warming world.
Formation of olivine veins by dehydration during viscously deforming serpentinite: a numerical study
Authors: Schmalholz Stefan Markus , Moulas Evangelos , Räss Ludovic , Müntener Othmar
Published: March 2022

The dehydration of serpentinite during subduction and the associated formation of dehydration veins is an important process for the global water cycle and the dynamics of the subducting plate. Field observations suggest that olivine veins can form by dehydration during viscous shear deformation of serpentinite. However, this hypothesis of olivine vein formation, involving the coupling of rock deformation, dehydration reactions and fluid flow, has not been tested and quantified by hydro-mechanical-chemical (HMC) models. Here, we present a new two-dimensional HMC numerical model to test whether olivine veins can form by dehydration during viscous shearing of serpentinite. The applied numerical algorithm is based on the pseudo-transient finite difference method. We consider the simple reaction antigorite + brucite = forsterite + water. Volumetric deformation is viscoelastic and shear deformation is viscous with a shear viscosity that is an exponential function of porosity. In the initial model configuration, total and fluid pressures are homogeneous and in the antigorite stability field. Small, initial perturbations in porosity, and hence in viscosity, cause pressure perturbations during far-field simple shearing. During shearing, the fluid pressure can locally decrease and reach the thermodynamic pressure required for the dehydration reaction, so that dehydration is triggered locally. The simulations show that dehydration veins form during progressive shearing and grow in a direction parallel to the maximum principal stress. During the dehydration the porosity can increase locally from 2% (initial value) to more than 50% inside the dehydration vein. The numerical model allows quantifying the mechanisms and variables that control the evolution of porosity and fluid pressure. We show that the porosity evolution is controlled by three mechanisms: (1) volumetric deformation of the porous solid, (2) temporal variation of the solid density and (3) mass transfer during the dehydration reaction. We quantify the evolution of the fluid pressure that is controlled by five variables and processes: (1) the total pressure of the porous rock, (2) elastic effects of the total volumetric deformation, (3) the temporal variation of porosity, (4) the temporal variation of solid density and (5) mass transfer during the dehydration reaction. This model supports the observation-based hypothesis of the formation of olivine veins due to dehydration during viscous shearing of serpentinite. More generally, our HMC model provides quantitative insights into the evolution of porosity, and hence dynamic permeability, fluid pressure and mass transfer during dehydration reactions in deforming rock.
Assessment of seasonal forecasts for reservoir operation in South Korea
Authors: Lee Yongshin , Pianosi Francesca , Rico-Ramirez Miguel , Peñuela Andres
Published: March 2022

Increased intensity and frequency of extreme weather events predicted in a warmer climate can cause damages to human life, properties and the natural environment. Also, these changes pose significant challenges to water resources management. For example, in South-Korea, there were prolonged droughts lasting more than 3 years from 2013 to 2015 whereas, record-breaking monsoon caused severe flood damages in 2020.  Nowadays the construction of new water infrastructure such as large reservoirs is almost impossible in many developed countries due to social and environmental objections and therefore the operation of existing reservoirs is extremely important. In order to improve the performance of reservoir operations, we need to make better use of reliable weather forecasting information.

There have been noteworthy advances in seasonal climate forecasts over the last decade. Seasonal forecasts are long-term meteorological forecasts (1 to 7 months) that could be a game changer in reservoir operation and adaptation to climate change once it is demonstrated that they provide reliable information in the water sector. However, so far seasonal forecasts have never been used in practice and simulation experiments similar to those reported in the scientific literature for other regions, such as Europe or the US, have not been conducted for South Korea.

Therefore, assessing the value of seasonal forecasts in reservoir operation is highly significant matter. In this study, we will try to demonstrate their value by comparing, via model simulation, the use of forecasts with the use of diverse scenarios, including deterministic low inflow scenarios (or worst cases), Ensemble Streamflow Prediction (ESP) and perfect forecast conditions (where observations are used in place of forecasts). The analysis will be carried out for 6 different reservoirs having different catchment sizes  from 95.4km2 to 1,584km2 to determine any link between forecasts value and catchment characteristics and draw general guidelines for future forecasts use. The results from each scenario will be compared in terms of ‘skill’, representing the forecast accuracy, and ‘value’, representing the final effect on reservoir operation such as water resources availability and flood prediction. This study aims at understanding how valuable the seasonal forecasts can be and how to apply them to have better performance in practice.
Processes of interannual internal variability of the CO2 flux at the air-sea interface in IPSLCM6A
Authors: Menary Matthew , Mignot Juliette , Bopp Laurent , Kwiatkowski Lester
Published: March 2022

In order to improve our ability to predict the near-term evolution of climate, it may be important to accurately predict the evolution of atmospheric CO2, and thus carbon sinks. Following on from process-driven improvements of decadal predictions in physical oceanography, we focus on improving our understanding of the internal processes and variables driving CO2 uptake by the North Atlantic ocean. Specifically, we use the CMIP6 model IPSLCM6A to investigate the drivers of ocean-atmosphere CO2 flux variability in the North Atlantic subpolar gyre (NA SPG) on seasonal to decadal timescales. We find that DpCO2 (CO2 partial pressure difference between atmosphere and ocean) variability dominates over sea surface temperature (SST) and sea surface salinity (SSS) variability on all timescales within the NA SPG. Meanwhile, at the ice-edge, there are significant roles for both ice concentration and surface winds in driving the overall CO2 flux changes. Investigating the interannual DpCO2 variability further, we find that this variability is itself driven largely by variability in simulated mixed layer depths in the northern SPG. On the other hand, SSTs show an important contribution to DpCO2 variability in the southern SPG and on longer (decadal) timescales. Initial extensions into a multi-model context show similar results. By determining the key regions and processes important for skilful decadal predictions of ocean-atmosphere CO2 fluxes, we aim to both improve confidence in these predictions as well as highlight key targets for climate model improvement. 
Geochemistry of ash leachates during the 2021 eruption of Cumbre Vieja volcano, La Palma, Canary Islands
Authors: Rodríguez Fátima , Pérez Nemesio M. , Amonte Cecilia , Martín-Lorenzo Alba , Melián Gladys V. , Coldwell Beverly C. , Pankhurst Matthew J. , Asensio-Ramos María , Hernández Pedro A. , Padrón Eleazar
Published: March 2022

On September 19, 2021, a new eruption began at the west flank of Cumbre Vieja volcano (La Palma, Canary Islands), after an inter-eruptive period of 50 years from the previous eruption (Teneguía, October 1971). The 2021 event was a fissure and powerful strombolian eruption with a magnitude VEI=3 and it has been considered as the most important eruption of Europe during the last 75 years in terms of the significant amount of SO2 released and the serious damage caused by the lava flows.

In this work we report the leachate analyses of volcanic ash from the beginning of the eruption, focused on determining the relationship between chemical composition of water‐soluble components adhering to volcanic ash and the volcano’s activity episodes. A total of 5 main control sites or ash-collecting stations were established and ash was picked up in a daily basis. These were located around the main eruptive vents at different distances. Water-extractable concentrations of the samples leached at 1:25 for 2 hours were analyzed by ion chromatography (Cl-, SO42-, F-, Br-, NO3-, Na+, Ca2+, Mg2+, K+) and ICP-MS (Li, B, Al, Si, Sr, Ba, Fe, Ti, Cu, Sb, Rb, Ni, Co, Cd, V). The most abundant components in the leachates were SO42- for the anions and Na+ for the cations, with mean concentrations of 854 and 455 mg/kg, respectively. The results showed the following trend, in decreasing order of abundance: SO4-2>Na+>Cl->F->Ca2+>Al3+>K+>Mg2+. Fluoride, an element of primary concern for human and animal health, showed a range of 16 and 733 mg/kg and an average of 239 mg/kg, which is relatively higher than global median value (129 mg/kg). The S/Cl molar ratio in the ash leachate presented a ranged of values from 0.16 to 5.9 and the observed values > 3.0 seems to be related to ash-rich phases of the eruption. Preliminary results show significant temporal variations in ash leachate compositions, revealing changes in the eruption dynamics.
Daily mapping of global surface temperature reveals intensified local extremes of Surface Urban Heat Island
Authors: Mentaschi Lorenzo , Duveiller Grégory , Zulian Grazia , Corbane Christina , Pesaresi Martino , Maes Joachim , Stocchino Alessandro , Feyen Luc
Published: March 2022

Urban temperatures are generally higher in cities than in their non-urbanized surroundings, both during day and night. This phenomenon, known as the Urban Heat Island effect, represents a hazard, as it exacerbates heat-related illnesses and mortality. Its intensity can be estimated from remote sensing retrievals of Land Surface Temperature (LST), and in such conditions it is usually referred to as Surface Urban Heat Island (SUHI). Past global studies analyzed this phenomenon in terms of urban and/or annual/seasonal means, but the impact on human health depend on short-term heat stress experienced locally. On the other hand, local studies are often performed on time-limited and not always representative empirical cases, employ different types of measurements and methodologies, making them difficult to intercompare. Moreover, they cover extensively a few developed areas, such as Northern America, Europe and Eastern Asia, leading to a knowledge gap with respect to less studied regions.

To fill this gap, here we developed a high resolution (1 km) dataset of observations of day and night SUHI based on 18 years of MODIS Aqua imagery, which offers an unprecedented insight into the short-time and short-range behavior of the Urban Heat Island. Our results show that 3-day SUHI extremes are on average more than twice as high as the warm-season median SUHI, with local exceedances up to 10 K, and with hotspots of intense heat and relatively cooler areas are clearly observable within the same city. Furthermore, over this period, SUHI extremes have increased more rapidly than warm-season medians, and averaged worldwide are now 1.04 K or 31% higher compared to 2003. This can be linked with increasing urbanization, more frequent heatwaves, and greening of the earth, processes that are all expected to continue in the coming decades.

These data provide clear evidence of the importance of high space-time resolution in studying the Urban Heat Island and the threat it poses. They can be used in a range of applications, from the day-by-day assessment of urban heat, to the calibration of models of the urban climate (Mentaschi et al., 2022).

 

References

Mentaschi, L., Duveiller, G., Zulian, G., Corbane, C., Pesaresi, M., Maes, J., Stocchino, A. and Feyen, L.: Global long-term mapping of surface temperature shows intensified intra-city urban heat island extremes, Glob. Environ. Chang., 72, 102441, doi:10.1016/j.gloenvcha.2021.102441, 2022.

 
PV and wind power simulation with ERA5 and ERA5-land – a multi-country analysis
Authors: Gruber Katharina , Ramirez Camargo Luis , Schmidt Johannes
Published: March 2022

Climate data sets are widely used for renewable power simulation. While previous generations of global reanalysis data including MERRA-2 and ERA-Interim have been widely assessed for their suitability to simulate variable renewable power systems, more recent datasets such as ERA5 and ERA5-Land lack validation, particularly in regions outside of Europe.

Here, we assess the accuracy and bias of wind power simulation using ERA5 wind speeds in Brazil and New Zealand as well as solar photovoltaic power simulation accuracy using ERA5-Land solar radiation and temperature data in Chile. We compare the performance of ERA5 and ERA5-Land to MERRA-2 based renewable power generation. The reference data sets are capacity factors derived from data measured at individual installations in each country and the performance indicators include the pearson’s correlation coefficient, mean bias error (MBE) and root mean square error (RMSE). For wind power simulation, we also assess a bias correction method using the Global Wind Atlas.

Since models applying the resulting datasets are based on different spatial and temporal scales, we also aim at finding a relation between the spatial and temporal resolution and simulation quality. We assess the simulation results applying spatial aggregation ranging from individual installations to the country level and temporal aggregation varying from hours to months. This aids to evaluate the reliability of the simulated renewable power generation time series on various spatiotemporal scales for future simulation efforts.

Overall, we find that both datasets, ERA5 and ERA5-Land, perform well in wind and solar photovoltaic power simulations. For wind power simulation, ERA5 shows improved performance compared to MERRA-2 based wind power simulation, while for solar photovoltaic the improvements of ERA5-Land compared to MERRA-2 are minor. Correlation of wind power generation is around 0.8 without correction and MBEs around -0.1. Mean bias correction with the Global Wind Atlas does not consistently improve simulation results. For the solar photovoltaic power simulation, we find correlations above 0.75, while the MBE is between -0.05 and 0.1.
Searching for the origin of plate tectonics, leaving no grain unturned 
Authors: Bercovici David
Published: March 2022

The physical cause, or origin, or generation of plate tectonics, especially how it arises from a convecting mantle on Earth (and not apparently on our solar system's other terrestrial planets) is one of the big questions in geophysics, and has  haunted (or taunted) the author  for the last 30+ years.  Although he's tried to drive the question to basic physical causes for plate boundary formation in a cold stiff lithosphere,  he's certainly taken his share of wrong turns.  His earliest attempts to understand these processes from fluid lab experiments (while a postdoc at WHOI) only achieved (1) making gallons of fluids that look much like mucus, and (2) proof that he was a lousy experimentalist.  But in the intervening decades, he's burrowed deeper into smaller and smaller scales to understand how microscale physics of mineral grains influence plate boundary formation at large scales.  This led to the most recent theory of grain damage that allows for formation of weak boundaries, corresponds to field and laboratory observations of mylonitic behavior, and has applications from the onset of early plate tectonics, to passive margin collapse, to slab segmentation and necking.   The most recent theory incorporates how mineral phases (olivine and pyroxene) mix with each other at the grain scale, and this has allowed a close comparison to new rock deformation experiments on grain mixing and shear localization, which opens up many new questions and predictions for more experiments and observations.  
Differences between lowlands and highlands in terms of compound wind-precipitation events
Authors: Müller Miloslav , Kašpar Marek , Křížová Milada
Published: March 2022

Extreme precipitation events are associated with cyclones, atmospheric fronts or convective storms which produce high winds as well. This fact increases the probability of compound wind-precipitation events. Such events can cause even more damage than single precipitation and wind events because, for example, soil moisture makes trees less stable. The joint effect is even more significant in case of solid precipitation due to snow accumulations on trees. However, as the orographic precipitation enhancement increases mainly cold-season precipitation totals in highlands, the altitude makes the difference in the seasonal distribution of precipitation in Czechia. Thus, the local lowlands and highlands also partly differ in terms of the frequency of compound wind-precipitation events. We present this fact on data series of maximum daily wind gusts, daily precipitation totals and inter-diurnal increases in show depth from the period 1961 – 2020 at selected Czech weather stations, located in various altitudes. Extreme events are defined by the method of percentiles; frequencies of compound events are evaluated in comparison to the stochastic frequencies.
Estimating the future sea level rise contribution of Thwaites glacier, Antarctica, using an uncertainty quantification approach
Authors: Rosier Sebastian , Gudmundsson Hilmar
Published: March 2022

Thwaites Glacier in West Antarctica may be the single largest contributor to sea level rise in the coming centuries, but existing projections over such timescales are highly uncertain. A number of factors contribute to this uncertainty and robust predictions involve many complex processes through the interaction between ice, ocean and atmosphere. Here, we use the Úa ice-flow model in conjunction with an uncertainty quantification approach to provide uncertainty estimates for the future (100 years’ time scale) mass loss from Thwaites, and the relative contribution of individual model parameters to that uncertainty. In a first step, we simulate Thwaites glacier from 1997 to present day for a wide variety of uncertain model parameters and compare key outputs from each simulation to observations.  Using a Bayesian probability framework we sample the model parameter space, using informed priors, to build up a model emulator, allowing us to provide uncertainty estimates for a range of future emission scenarios. We show how this framework can be used to quantify the relative contribution of each model parameter to the total variance in our estimation of the future mass loss from the area. This, furthermore, allows us to make clear quantitative statements about different sources of uncertainty, for example, those related to external forcing parameterizations (e.g. surface mass balance) as compared to uncertainties in ice-flow parameters (e.g. basal sliding).    
DIY Neutron detection: Boron-based Large-scale Observation of Soil Moisture (BLOSM) 
Authors: van de Giesen Nick , van Amelrooij Edward
Published: March 2022

The ratio between slow or thermal (<2.2 km/s) and fast (>2.2 km/s) neutrons is known to be a good measure of the amount of water present in a radius of about 300m from the measurement. COSMOS detectors use this principle and measure neutrons by means of the helium isotope 3He. COSMOS has been in use for some time now and its large-scale observations are central to bridging the scaling gap between direct gravimetric observation of soil moisture (<<1m2) and the scale at which soil moisture is represented in hydrological models and satellite observations (>100m2). The main sources of 3He were nuclear warheads. The fortunate demise of nuclear weapons has had the less fortunate consequence that 3He has become expensive, leading to a search for more affordable alternatives.

Here, we present laboratory results of a boron-based neutron detector called BLOSM. About 20% of naturally occurring boron is 10B, which has a large cross-section for thermal neutrons. When 10B absorbs a neutron, it decays into lithium and alpha particles. Alpha particles can then be detected by ZnS(Ar), which sends out UV photons. Because real-estate is at a premium for most neutron detection applications, most boron detectors are based on relatively expensive enriched boron with >99% 10B. In hydrology, space is usually less of an issue, so one innovation here is that we use natural boron in a detector that is simply a bit larger than one based on enriched boron but much cheaper. A second innovation, put forward by Jeroen Plomp of the Delft Reactor Institute, are wavelength shifting fibers that capture UV photons by downshifting the wavelength to green. Green photons have a wider angle of total internal reflection and tend to stay in the fiber until they exit at the end. Here, a third innovation comes into play, inspired by Spencer Axani's $100 muon detector, namely the use of simple electronics and silicon photon multipliers (SiPMs).

Because we want to know the ratio between fast and slow neutrons, we need two detectors, one that just counts the thermal neutrons that continuously zap around and through us, and one covered by a moderator that slows down faster neutrons to thermal levels, so that they can be detected. Presently, we can build two detectors for about EU 1000. We expect that after the development of some custom electronics, this will come down to around EU 500. Ideally, we would like to build a network of these detectors in Africa in conjunction with the TAHMO network (www.tahmo.org).
Solid-phase extraction of aquatic organic matter: loading-dependent chemical fractionation and self-assembly
Authors: Kong Xianyu , Jendrossek Thomas , Ludwichowski Kai-Uwe , Marx Ute , Koch Boris
Published: March 2022

Dissolved organic matter (DOM) is an important component in marine and freshwater environments and plays a fundamental role in global biogeochemical cycles. In the past, optical and molecular-level analytical techniques evolved and improved our mechanistic understanding about DOM fluxes. For most molecular chemical techniques, sample desalting and enrichment is a prerequisite. Solid-phase extraction (SPE) has been widely applied for concentrating and desalting DOM. The major aim of this study was to constrain the influence of sorbent loading on the composition of DOM extracts. Here we show that increased loading resulted in reduced extraction efficiencies of dissolved organic carbon (DOC), fluorescence and absorbance, and polar organic substances. Loading-dependent optical and chemical fractionation induced by altered adsorption characteristics of the sorbent surface (PPL) and increased multilayer adsorption (DOM self-assembly) can fundamentally affect biogeochemical interpretations, such as the source of organic matter. Online fluorescence monitoring of the permeate flow allowed to empirically model the extraction process, and to assess the degree of variability introduced by changing the sorbent loading in the extraction procedure. Our study emphasizes that it is crucial for sample comparison to keep the relative DOC loading (DOCload [wt%]) on the sorbent always similar to avoid chemical fractionation.
Recycling Etna volcanic ash for the production of ceramic materials
Authors: Belfiore Cristina Maria , Viccaro Marco
Published: March 2022

The presence of active volcanoes often influences human life both in terms of health impact and socio-economic consequences. Explosive eruptions can release into the atmosphere huge quantities of ashes which then fall to the ground, causing many inconveniences to communities living and working in close proximity to the volcano. A further problem is represented by the high costs that the involved administrations (Civil Protection or Municipalities) of the interested areas must face whenever this material, considered as waste, needs to be collected and disposed of in landfill.

To overcome this problem, it would be suitable to find ‘‘end of waste” alternatives for volcanic ash as raw material in the productive sectors, e.g., in building materials (tiles, bricks, mortars, concretes, etc.). A paradigm shift leading to consider ashes no longer as a waste but a resource.

This contribution deals with an experimental study aimed at assessing the possible re-use of volcanic ash as temper in the manufacture of ceramic tiles. Volcanic ashes recently erupted by Mount Etna volcano in Sicily (Southern Italy), one of the most active basaltic volcanoes in the world, have been here chosen as case study for such a purpose. Ceramic test-tiles were manufactured by mixing volcanic ash with a calcareous clayey raw material, by using specific proportions of clay/temper. In order to assess the quality of the products, the tiles underwent several physical–mechanical tests including: a) water absorption; b) bending resistance; c) impact resistance; d) resistance to deep abrasion; e) thermal shock resistance; f) frost resistance; and g) accelerated aging test by salt crystallization (Belfiore et al. 2020). The obtained results have been then compared with those of a reference product manufactured by using another volcanic material known as azolo (i.e., finely ground basalt) for a long time on the market. Our data demonstrate how basaltic ash recovering through this methodological approach is highly promising in the sector of building materials.

Reference

Belfiore C.M., Amato C., Pezzino A., Viccaro M., 2020. An end of waste alternative for volcanic ash: A resource in the manufacture of ceramic tiles. Construction and Building Materials, 263, 120118, doi: 10.1016/j.conbuildmat.2020.120118
Evaluation of the new TOA radiation fields in the CM SAF CLARA-A3 Climate Data Record.
Authors: Clerbaux Nicolas , Akkermans Tom
Published: March 2022

The Climate Monitoring SAF (CM SAF) of EUMETSAT is finalizing the third version of the CLoud Albedo and RAdiation based on AVHRR climate data record (CLARA-A3). This new version will cover the 1979-2020 time period and will provide the Top-of-Atmosphere (TOA) radiative fluxes as new products.  

Although the Clouds and the Earth’s Radiant Energy System (CERES) products are acknowledged to be the golden standard w.r.t. TOA radiative flux data records, two limitations can be identified: (1) the products are relatively recent, e.g. starting in year 2000 for the EBAF product, and (2) the products have a relatively coarse spatial resolution of 1°x1° (lat-lon equal angle grid). The products developed within CM SAF aim to bridge these gaps, respectively by (1) a prolongation back in time to the late 1970s and (2) by increasing the spatial resolution to 0.25°x0.25°. A third advantage of the new CDRs lies in their synergy and compatibility with the other CDRs from the CM SAF CLARA product family (cloud mask and other cloud parameters, surface radiation, surface albedo, etc.) sharing common algorithms and processing chains.

The CLARA-A3 data record has been completed but not yet released, and hence we can present a validation of daily and monthly Reflected Solar Flux (RSF) and Outgoing Longwave Radiation (OLR). CLARA-A3 performance is assessed in terms of bias, regional uncertainty (spatial RMSE), and stability. This is done primarily with the relatively recent CERES and GERB broadband-based reference products, and additionally also with long-term data records such as from HIRS, ERA-5, ISCCP, and ESA-CCI to assess the stability throughout the entire data record. Overall, the performance is within the expected target requirements. Regional uncertainty is however related to the number and of observations per day and their local time, which are both variable throughout the AVHRR and MetOp constellation history.