bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal monitoring of river and lake water surface areas at global scale with deep learning.
Authors: Carbonneau Patrice , Bizzi Simone
Published: February 2023

Much progress has been made over the last decade to build global inventories of freshwater resources. However, existing freshwater inventories are generally produced for a fixed period in time and/or do not discriminate lakes and rivers. The emergence of deep learning methods and Big Data platforms such as Google Earth Engine offers a potential solution. Here we present a unique raster dataset of 6.7 terapixels at a spatial resolution of 10 m produced with a deep learning workflow. This dataset uses Sentinel-2 imagery downloaded from Google Earth Engine to delineate freshwater as separate semantic classes of rivers and lakes. Our study site covers the non-polar globe, 89% of the terrestrial landmass, with repeat surveys for the months of April, July and October 2021. This gives us the first global-scale direct count of lakes larger than 1 hectare as ~7.3 million. Also the repeat surveys allow us to present the first intra-annual ranges for the areas distinctly occupied by rivers and lakes where we find that basins influenced by the Asian summer monsoon (e.g. the Ganges) closely followed by the Amazon display the largest intra-annual range of river area per unit basin area. Finally, we find that whilst maximum of lake water surface occurs in October 2021, the maximum river surface is in July 2021 leading us to conclude that the global maximum occurrences of river water and lake water are not synchronous.
Is destabilisation risk increasing in land carbon sinks?
Authors: Fernández-Martínez Marcos , Peñuelas Josep , Chevallier Frederic , Ciais Philippe , Obersteiner Michael , Rödenbeck Christian , Sardans Jordi , Vicca Sara , Yang Hui , Sitch Stephen , Friedlingstein Pierre , Arora Vivek K. , Goll Daniel , Jain Atul K. , Lombardozzi Danica L. , McGuire Patrick C.
Published: February 2023

Global net biome production (NBP), or net land carbon uptake, has been repeatedly shown to increase during recent decades. However, whether the temporal variability and autocorrelation of NBP has changed during this period remains elusive. Answering this question is particularly relevant given that an increase in both could indicate destabilising C sinks and potentially lead to abrupt changes. We investigated the trends and controls of net land C uptake and its temporal variability and autocorrelation, from 1981 to 2018, using two atmospheric inversion models, the amplitude of the seasonal cycle of atmospheric CO2 derived from nine monitoring stations distributed across the Pacific Ocean, and 12 dynamic global vegetation models. Spatially, we found that plant biodiversity presented a convex parabolic relationship with NBP and its temporal variability at the global scale while nitrogen deposition generally increased annual NBP. We also found that annual NBP and its interdecadal temporal variability globally increased, but temporal autocorrelation decreased. Regions characterized by increasingly variable NBP were usually with warmer and with increasingly variable temperatures, and lower and weaker trends in NBP compared to those where NBP variability did not increase, where NBP became stronger. Annual temperature increase and its increasing temporal variability were the most important drivers of declining NBP and increasingly its variability. Our results show that increasing regional NBP variability can be mostly attributed to climate change.
"Global Deep Soil 2100" network - an update
Authors: Schmidt Michael W. I. ,   Deep Soil 2100
Published: February 2023

“Global Deep Soil 2100” is a network for whole-ecosystem warming experiments. The aim of DeepSoil 2100 is to bring together researchers working on long-term experiments. The year ‘2100’ was chosen because IPCC scenarios run until 2100. We welcome whole ecosystem manipulations, warming down to one meter, with or without other manipulations such as water and carbon dioxide concentrations, and studying responses of plants, soil biogeochemistry, ecology, etc.There are less than a dozen whole-ecosystem warming experiments but not all researchers know about each other. To introduce experiments and involved scientists, we started video meetings end of 2020. This effort brought together experimentalists, modelers and data users into this “whole-ecosystem warming network”, to share practical experience on field experiments, data reporting, discuss observations and results and explore synergies regarding tools, knowledge, and data sharing and interpretation. You can view previous meeting recordings here:  https://tube.switch.ch/channels/ed725365A first workshop to further data compilation and meta analysis and modeling is scheduled for March 2023. Further details and contact can be found on the webpage of the “International Soil Carbon Network”  https://iscn.fluxdata.org/network/partner-networks/deepsoil2100/
Future reversal of warming-enhanced vegetation productivity in the Northern Hemisphere
Authors: Zhang Yichen , Piao Shilong , Sun Yan , Rogers Brendan M. , Li Xiangyi , Lian Xu , Liu Zhihua , Chen Anping , Peñuelas Josep
Published: February 2023

Climatic warming has greatly increased vegetation productivity in the extratropical Northern Hemisphere since the 1980s, but how long this positive relationship will continue remains unknown. Here we show changes in the effect of warming on Northern Hemisphere summer gross primary productivity for 2001–2100 using Earth system model outputs. The correlation between summer gross primary productivity and temperature decreases in temperate and boreal regions by the late twenty-first century, generally becoming significantly negative before 2070 in regions <60° N, though Arctic gross primary productivity continues to increase with further summer warming. The time when the correlation becomes negative is generally later than the time when summer temperature exceeds the optimal temperature for vegetation productivity, suggesting partial mitigation of the negative vegetation impacts of future warming with photosynthetic thermal acclimation. Our findings indicate that vegetation productivity could be impaired by climate change in the twenty-first century, which could negatively impact the global land carbon sink.
Paleoclimatic and paleoenvironmental changes in the Pantanal region during the Holocene based on speleothem records
Authors: Novello Valdir , Ritzau Magdalena , Cruz Francisco , Buehler Janica , Rehfeld Kira
Published: February 2023

The Pantanal is a large region located in the central parts of South America (140,000 km2) with a unique climate and vegetation setting. This region is subjected to seasonal floods, which makes the Pantanal one of the most important wetlands on the planet. In this region occur transitions between different biomes, such as the Amazon Forest, Cerrado (Brazilian Savanna), and Atlantic Forest, located to the North, East, and South of this region, respectively. The area also serves as a moisture pathway for the South American Summer Monsoon (SASM), which connects the Amazon Basin with the La Plata Basin. The two major drainage basins of South America. Due to the complex hydrology of the rivers and lakes of this region, it is necessary to combine multiple proxy archives from different parts of the Pantanal basin to understand its climate and vegetation evolution during the Holocene.Here we present isotope records from stalagmites collected at sites located at the northern and southern borders of the Pantanal. Hiatuses in speleothem deposition during the mid-Holocene identified in several stalagmites indicate overall dry conditions in the region at this period. However, the drier conditions recorded in the northern portion of the basin precede similar conditions in the South by approximately two thousand years. Furthermore, summer insolation seems to drive the intensity of the SASM at the North Pantanal, while its influence is weaker in the southern part. During the late Holocene, this establishes a moisture gradient between a wetter North and drier South. Our record also shows a strong multidecadal to centennial variability, which was probably responsible for the high hydrology complexity of the rivers of the Pantanal, which are subject to seasonal floods and migration of its channels and tributaries.
The contemporary Amazon Forest carbon budget
Authors: Rosan Thais M. , Sitch Stephen , O’Sullivan Michael , Wilson Christopher , Basso Luana S. , Fawcett Dominic , Heinrich Viola A. , Souza Jefferson G. , von Randow Celso , Mercado Lina M. , Gloor Emanuel , Gatti Luciana , Friedlingstein Pierre , Wiltshire Andy , Pongratz Julia , Schwingshackl Clemens , Aragão Luiz E.O.C. ,   TRENDY-v11 Team
Published: February 2023

The Amazon is the largest continuous tropical forest in the world and plays a key role in the global carbon cycle. Human-induced disturbances (e.g., deforestation and wildfires) in combination with climate change have impacted its carbon cycling. However, uncertainties remain on the magnitude of carbon fluxes associated with human-induced disturbances and the old-growth forest sink, and thus the net land carbon balance of the Amazon. Here we synthesize state-of-the-art estimates of the land carbon flux components in the Amazon. To quantify the human-disturbance fluxes from deforestation, land use and land cover changes and degradation, we use a set of bookkeeping models. The annual intact sink was quantified using a set of 16 Dynamic Global Vegetation Models (DGVMs). We then combine the carbon flux estimates from disturbances with the intact sink estimates to provide a bottom-up estimate of the net land carbon flux and compare them alongside top-down estimates from atmospheric model inversions. Between 2010 and 2018, the net land carbon flux in the Brazilian Amazon estimated with the bottom-up approach was -59 (±160) Tg C yr-1 and +36 (±125) Tg C yr-1 with the top-down approach. Despite disagreeing on the sign of the flux, this analysis suggests that the Brazilian Amazon was on average near carbon neutral over the 2010-2018 period, given the large uncertainties underlying both methods. The net land carbon fluxes for the years 2019 and 2020 based on the bottom-up approach were larger than for 2010-2018. This is likely primarily due to direct emissions related to an increase in deforestation although it may possibly be partly caused by a weakening of the forest carbon sink, both in response to deforestation and a warming climate. Spatially, both methodologies agree that the south-eastern Amazon was a net carbon source over the whole study period. These results have important implications for the mitigation potential of Brazilian ecosystems within the goals of the Paris Agreement.  
Drought risk assessment under climate change impacts utilizing CMIP6 climate models in the coastal zone of the Mekong Delta
Authors: Bui Nghia , Pal Indrajit , Chollacoop Nuwong
Published: February 2023

Drought is a natural hazard that occurs every year in the Mekong Delta of Vietnam (MDV). In recent years, drought has become more severe, increasing socio-economic risk. Climate change is one of the primary reasons aggravating the level of drought. Therefore, giving a drought risk assessment that integrates climate change impacts is crucial. This study contributes to a proof-of-concept comprehensive drought risk assessment under the impacts of climate change in the coastal provinces of the MDV. The risk of MDV for climate hazards has been assessed considering three key elements - hazards, exposure, and vulnerability. Three CMIP6 global climate model datasets – MIROC6, CESM2, and CNRM-CM6-1 – and two Shared Socioeconomic Pathways of SSP2-4.5 and SSP5-8.5 are selected to project climate change from 2025 to 2100. The Standardized Precipitation Evapotranspiration Index (SPEI) has been used to assess the future drought hazard. Drought exposure and vulnerability are derived using statistical data on natural and socioeconomic characteristics from provincial statistical yearbooks. The results of this study will benefit policymakers to develop risk management strategies in minimizing the drought risks in the coastal estuarine deltas under the long-term impacts of climate change.
Running web-based model chains via ESA’s Virtual Space Weather Modelling Centre
Authors: Poedts Stefaan ,   VSWMC-P3 team
Published: February 2023

The ESA Virtual Space Weather Modelling Centre (VSWMC) project was defined as a long term project including different successive parts. Parts 1 and 2 were completed in the first 4-5 years and designed and developed a system that enables models and other components to be installed locally or geographically distributed and to be coupled and run remotely from the central system. A first, limited version went operational in May 2019 under the H-ESC umbrella on the ESA SSA SWE Portal. It is similar to CCMC but interactive (no runs on demand) and the models are geographically distributed and coupled over the internet. The goal of the ESA project "Virtual Space Weather Modelling Centre - Part 3" (2019-2022) was to further develop the Virtual Space Weather Modelling Centre, building on the Part 2 prototype system and focusing on the interaction with the ESA SSA SWE system. The objectives and scope of this new project include maintaining the current operational system, the efficient integration of 11 new models and many new model couplings, including daily automated end-to-end (Sun to Earth) simulations, the further development and wider use of the coupling toolkit  and front-end GUI, making the operational system more robust and user-friendly.The 11 new models that have been integrated are Wind-Predict (a global coronal model from CEA, France), the Coupled Thermosphere/Ionosphere Plasmasphere (CTIP) model, Multi-VP (another global coronal model form IRAP/CNRS, France), the BIRA Plasma sphere Model of electron density and temperatures inside and outside the plasmasphere coupled with the ionosphere (BPIM, Belgium), the SNRB  (also named SNB3GEO) model for electron fluxes at geostationary orbit (covering the GOES 15 energy channels >800keV and >2MeV) and the SNGI geomagnetic indices Kp and Dst models (University of Sheffield, UK), the SPARX Solar Energetic Particles transport model (University of Central Lancashire, UK), Spenvis DICTAT tool for s/c internal charging analysis (BISA, Belgium), the Gorgon magnetosphere model (ICL, UK), and the Drag Temperature Model (DTM) and operations-focused whole atmosphere model MCM being developed in the H2020 project SWAMI. Many new couplings have also been implemented which can be used interactively. Moreover, daily runs are implemented of several model chains covering the whole Sun-to-Earth domain. The results of these daily runs are made available to all VSWMC users. We will provide an overview of the state-of-the-art, including the new available model couplings and daily model chain runs, and demonstrate the system.
SuDS+: establishing a new vision for sustainable drainage in delivering sustainable and resilient urban communities
Authors: Starkey Eleanor , Rollason Edward
Published: February 2023

Nature-based Sustainable Drainage Systems (SuDS) have been promoted for enhancing urban drainage, as well as offering additional benefits to urban greening and amenity, and engaging communities in the design and adoption of schemes. However, a lack of data on the efficacy of nature-based options means that schemes often use traditional engineering approaches instead of nature-based designs. Where nature-based options are used, most schemes lack long-term monitoring to understand their effectiveness; interventions are rarely designed to maximise their potential and often underperform once constructed. Existing practices also mean that most schemes are led by technical expertise and hence proceed with token public engagement, and lack support for community acceptance and adoption. This is unsustainable and undermines SuDS as a crucial tool for climate adaptation and sustainable urban development.The SuDS+ approach argues for a radical rethink of the benefits of SuDS, de-prioritising drainage as their primary driver, and instead conceptualising ‘SuDS+’ as a multi-benefit urban development tool with a range of co-, not additional, benefits. In this approach SuDS become a vehicle for enhancing urban design, amenity, and health and wellbeing which can be adapted to meet community needs and aspirations.The SuDS+ project, a 5-year Defra funded study in the Northeast of England, aims to develop and deliver community-centred SuDS, embedding innovation in collaborative design, as well as pushing forward new technologies and approaches for nature-based urban water management, and co-developing our understanding of what and how to monitor interventions to develop a robust evidence-base for the future.This paper outlines the key challenges and how the project will aim to tackle these as a call to reimagine SuDS as a vehicle for delivering greener, healthier, more sustainable, and more resilience urban communities.
Seismicity and active tectonics: New insights from Sikkim Himalaya
Authors: Uthaman Mita , Singh Chandrani , Singh Arun , Dutta Abhisek , Kumar Dubey Arun , Kumar Gaurav
Published: February 2023

The Himalayas, which formed as a result of the impactful collision of the Indian plate with Eurasian plate, is a tectonically complex and seismically active region. It has been a hotspot for many great earthquakes in the past. The continued collision coupled with the complex structural features has led to the persistent seismic activity of the region. The progressive collision led to the formation of distinct tectonic units bounded by thrust faults. The northeastern state of Sikkim in India, which is sandwiched between Nepal and Bhutan in the Himalayas, has been prone to frequent great earthquakes. The deployment of a dense seismic network consisting of 27 broadband seismometers, across Sikkim Himalayas and the northern part of West Bengal, since April 2019 has enabled us to monitor the seismic activity in the study region.Here, we present a study which aims at understanding the seismotectonic activity of the study region using local earthquakes (epicentral distance < 200km) recorded by the network between April 2019 and September 2022. The progressively improved relocation of local earthquakes recorded in the study region shows a diffuse cloud of micro-seismicity concentrated along a diagonal region extending from north of Assam in the southeast to south of Tibet in the northwest. From south to north we have observed clusters of earthquakes with a gradual increase in their hypocentral depths.The upper-crustal earthquakes (~0-25km) are located near the down-dip end of the locked part of the Main Himalayan Thrust (MHT), along which India underplates Tibet. We also observe prominent lower crustal earthquakes at depths greater than 30 km. These earthquakes are possibly originating at the junctions of different blocks in an imbricated crust in response to active shortening. We also observe a mid-crustal seismicity pattern following the DCFZ (Dhubri-Chungthang Fault Zone), supporting observations from earlier studies. Striking variations are observed in the faulting mechanisms and orientation of stress axes along the north-south and east-west profiles, and also with depth. We plan to further investigate if these variations imply the presence of possible segmentation, its depth, extent, surface expression and determine its relation to the geodynamics of the region. Integrating the results obtained from the various studies and interpreting them will help in delineating the seismotectonic activity of the study region. Quality data recorded by the dense network will further complement in enhancing the resolution of the results obtained.
Forecasting of tropospheric parameters using meteorological data and machine learning
Authors: Crocetti Laura , Schartner Matthias , Schindler Konrad , Soja Benedikt
Published: February 2023

Radio signals sent by Global Navigation Satellite System (GNSS) satellites are received by GNSS stations on Earth. The signals get delayed as they propagate through the troposphere, this delay can be measured and thus, tropospheric properties can be estimated.The total tropospheric delay in zenith direction is split into a zenith hydrostatic delay (ZHD) and a zenith wet delay (ZWD). While the ZHD can be modelled analytically with high accuracy, the ZWD is more difficult to model and is therefore typically estimated empirically. Estimating ZWD with high accuracy is important because it is one of the major error sources for GNSS positioning. Furthermore, the ZWD is highly correlated to the water vapour content along the signal path and thus, interesting for GNSS meteorology. Therefore, many studies have investigated new methods to improve state-of-the-art ZWD models. Recently, also machine learning (ML) approaches have been used to create tropospheric delay models. In addition to modelling ZWD, forecasting of ZWD is of great importance. Due to the relation of ZWD to water vapour, accurate ZWD forecasts would be essential for weather forecasting.The aim of this work is to develop a global ML-based model capable of forecasting ZWD for the next 24 hours at any point on Earth. It is trained on ZWDs, provided by the Nevada Geodetic Laboratory,  from over 10'000 GNSS stations and evaluated on ZWDs of 2700 test stations. The model utilizes the geographical location of the GNSS station and meteorological data from the ERA5 data set as its input features. To make hourly ZWD forecasts for the next 24 hours, forecasts of the meteorological data are taken from the Integrated Forecasting System of the European Centre for Medium-Range Weather Forecasts (ECMWF). Preliminary results using Extreme Gradient Boosting (XGBoost) show an average root mean squared error of around 1.5 cm over all testing stations for a forecasting horizon of 24 hours per day.
Tropospheric Ozone Trends in the Arctic
Authors: Law Katharine , Liengaard Hjorth Jens , Pernov Jakob , Whaley Cyndi , Skov Henrik , Collaud Coen Martine , Langner Joakim , Arnold Stephen ,   Arctic tropospheric ozone team
Published: February 2023

Tropospheric ozone, an important air pollutant and short-lived climate forcer, is changing globally with reported increases over emission regions that can influence ozone downwind. Here, ozone trends are examined in the Arctic troposphere, where surface warming is around four times faster than the global mean. Trends at the surface and in the free troposphere are estimated for 1993-2019 using available surface and ozonesonde data. Observed trends are also compared to modelled trends from the Arctic Monitoring Assessment Project (AMAP) multi-model evaluation, where models were run with the same anthropogenic emissions from 1990 to 2015 (Whaley et al., 2022, ACP). Findings include observed increases in annual mean surface ozone at Arctic coastal sites notably driven by increases during winter that are concurrent with decreasing surface carbon monoxide trends. Positive trends are also diagnosed at most high-Arctic ozonesonde sites in the wintertime free troposphere (up to 400 hPa). These ozone increases, which tend to be overestimated by the multi-model median (MMM) trends, are likely to be due to reductions in anthropogenic emission of nitrogen oxides at mid-latitudes leading to less ozone titration and influencing northern hemispheric ozone. Springtime increases are also found at the surface in northern coastal Alaska/Greenland but not in the MMMs. Causes are unknown but may be related to changing Arctic sea-ice or weather patterns affecting ozone sources or sinks. In contrast, surface ozone trends in northern Scandinavia are negative during spring, likely a response to decreasing ozone precursor emissions in Europe. MMM trends are also negative but generally overestimated. Springtime trends in the free troposphere also tend to be negative while summer trends are positive. Changes in ozone precursor emissions, the downward stratospheric ozone flux or general circulation may be contributing to these seasonal variations in the trends. The implications of these reported trends and model behaviour are discussed.
MACIV: a new project on multiscale seismic imaging of Massif Central (France) focusing on recent intraplate volcanism
Authors: Paul Anne , Mordret Aurélien ,   MACIV Team (1, 2, 3, 4)
Published: February 2023

Volcanic hazard is still an issue in the French Massif Central (FMC) because the last eruptions are dated 6700 yrs BP. Indeed, seismic bursts and geodetic uplift related to volcano-magmatic activity have recently been detected in the Eifel region (Germany), which belongs to the same European Cenozoic rift system as the FMC. However, geophysical knowledge of the sources of FMC volcanism is limited to the mantle-plume hypothesis, which dates from the last seismological experiment performed >30 years ago. To improve our knowledge on the deep structures of the FMC and the sources of volcanism, a multidisciplinary team of geophysicists, geologists, and volcanologists has set up the MACIV project, in a context of solid synergy with ongoing and future research initiatives in France and Europe (e.g. AdriaArray). Between 2023-2026, we will deploy several hundreds of seismic instruments in a multiscale configuration to probe the different scales and depths of the FMC volcanic systems with optimal spatial resolution. The entire FMC will be covered with broadband seismic stations in a 2-D array (spacing ~35 km) and three transverse profiles (spacing 5-20 km) for durations of 1.5-3 yrs. These arrays will provide information on the causes of mantle melting at depth, their links with the expression of volcanism at the surface, and the influence of Variscan and Cenozoic lithospheric structures. On a smaller scale, dense large-N arrays of ~650 short-period stations will provide images of the upper crust below the volcanoes and illuminate their plumbing systems. The enhanced earthquake detection power of the dense arrays will illuminate active faults and possible plumbing systems of the youngest volcanoes. The MACIV project will help better evaluate the volcanic hazard and provide a framework for a monitoring strategy scaled to a currently dormant volcanic province. The resulting seismological dataset will be used for years to come to yield essential information on intraplate volcanism.
Factors influencing subseasonal predictability of Northern Eurasian cold spells
Authors: Erner Irene , Karpechko Alexey , Järvinen Heikki
Published: February 2023

The study focuses on identifying potential “windows of opportunity” for the enhanced predictability of extreme events, such as severe Northern Eurasian cold air outbreaks as these events have significant impacts on human health, energy use, agriculture and welfare.  The extended-range predictability of extreme events is closely related to the preceding large-scale circulation patterns and remote teleconnections. To assess the predictability of these events and attribute their causes we use ensemble hindcasts (i.e., reforecasts for dates in the past) from five prediction systems from the S2S database – namely, from the European Centre for Medium‐range Weather Forecasts (ECMWF), the United Kingdom Met Office (UKMO), Météo‐France (CNRM), Bureau of Meteorology (BoM), Japan Meteorological Agency (JMA). These models have long re-forecast periods and big ensemble sizes necessary to establish statistically robust results. Moreover, the comparison of the forecasts from these six models evaluates the ability of modern prediction systems to forecast extreme events well in advance and highlights the main sources of predictability. We subsample the hindcasts into two groups according to their skill to predict an extreme event beyond weather predictability horizon (lead time week 2 and 3) in order to study the systematic relationship between preceding conditions and the onset of extreme events. Next, we evaluate the flow configurations in the initial conditions: the state of the stratospheric polar vortex (SPV), the phase and amplitude of the Madden-Julian Oscillation (MJO) in the tropics, and the weather regimes over the North Atlantic and Europe. This analysis provides a systemic evaluation and understanding of the large-scale patterns that can potentially contribute to the onset of extreme events over Eurasia, therefore, extending their predictability. Our results show that in overall models tend to over-predict cold conditions after certain states of the remote drivers but there is case-to-case variability in the predictability of the individual events. Moreover, this study assesses and compares the results from several state-of-art predicting systems which provides useful information for model developers as well as for forecast users.
Characteristics of Latest Eruption in the Tatun Volcano Group, North Taiwan
Authors: Song Sheng-Rong
Published: February 2023

Volcanic eruptions used to cause huge disasters which usually bring about many fatalities and property damages, especially a big city near the volcanoes. The Taipei metropolitan city is located at the foot of Tatun Volcano Group (TVO), which has been identified as an active volcano. Meanwhile, several volcanic islands are distributed in the offshore of northern Taiwan, which may be the active volcanoes. Thus, the past eruptive behaviors and mechanisms, characteristics of products, volcanic history and activity, etc.Based on the field observations, geomorphologic analyses, characteristics of ejecta, as well as the cases of world volcanoes, the explosive craters distributed in both sides of Chihsingshan volcano were produced by the phreatic eruption. Generally, two models of phreatic eruption have been proposed. One is a deeper hydrothermal system fed by magmatic gases being sealed and produces overpressure sufficient to drive explosive eruptions, and the other where magmatic gases are supplied via open-vent degassing to a near-surface hydrothermal system, vaporizing liquid water which drives the phreatic eruptions. The mechanism of Chihsingshan phreatic eruption is similar to the type I, which has hydrothermal reservoir underneath the volcano. Comparing other types of phreatic eruption in the world, for example, Mt. Ontake (Japan)、Inyo Craters (USA) and Tarawera Rift (New Zealand), they have similar common characteristics, (i) occurred in rifting conditions, (ii) heat source from magma intruded along the faults, (iii) had water body, such as groundwater, lakes or hydrothermal fluids, etc. near the conduit of magma. The geology and mechanism of phreatic eruption in the Chihsingshan volcano is more or less similar to the 2014 phreatic eruption of Mt. Ontake, Japan.
TREAD daTa and pRocesses in sEismic hAzarD: a MSCA-Doctoral Networks project 2023-2027
Authors: Pace Bruno , Benedetti Lucilla , Van Dinther Ylona , Pagani Marco , Marsan David , Gabriel Alice , Ortuno Maria , Di Toro Giulio , Meier Men-Andrin ,   TREAD working group
Published: February 2023

TREAD is a new project funded by the European Commission in the framework of Marie Sklodowska-Curie actions, Horizon Europe Doctoral Networks.
The aim of TREAD is to train a new generation of researchers to tackle the challenges of earthquake forecasting in complex tectonic settings using integrated observations and physics. The TREAD objectives are: (i) to develop a novel integrative approach to seismic hazard analysis in Europe and the Mediterranean from small-scale laboratory experiments to large-scale observations. (ii) to establish physics-based earthquake modelling bridging time scales from millions of years to fractions of a second in complex tectonic settings. (iii) to improve the link between earthquake geology, computational modelling and hazard and risk assessment with a focus on the needs of governments, industry and scientific stakeholders.

To reach these objectives the TREAD consortium comprises 14 academic and 8 non-academic institutions, of which 8 private partners, of high scientific level, from 7 European countries, covering cutting-edge knowledge and expertise in observational, experimental and modelling fields. 11 PhD positions will be available soon.
Alterations of soil organic matter following 130 years of afforestation assessed by molecular markers
Authors: Speckert Tatjana Carina , Wiesenberg Guido Lars Bruno
Published: February 2023

In alpine areas of the European Alps, many of the pastures are no longer economically profitable and are converted into forests (Bolli et al., 2007). Afforestation on former pastures affects soil organic matter (SOM) dynamics through alteration of quality and quantity of root and aboveground biomass litter input. Compared with pasture OM, forest OM is less decomposable and characterized by increased C:N ratio as well as increased lignin concentration (Hiltbrunner et al., 2013). Therefore, it could be expected that long-term afforestation on a centennial scale may have a severe impact on SOM dynamics, an aspect that remains so far unknown as most of the earlier studies focused on successions between 30 and 50 years (Vesterdal et al., 2002).In the current study, we aimed to identify the major sources of SOM in a subalpine afforestation sequence (40-130 years) with Norway spruce (Picea abies L.) on a former pasture in Jaun, Switzerland. Therefore, we combined plant- and microorganism-derived molecular proxies from several compound classes such as free-extractable fatty acids and phospholipid fatty acids.We observed a decline in soil organic carbon (SOC) stock (9.6 ± 1.1 kg m-2) after 55 years and a recovering of the SOC stock 130 years (12.7 ± 0.9 kg m-2) after afforestation. Overall, there is no alteration of the SOC stock in the mineral soil following afforestation of former pasture (13.3 ± 0.9kg m-2) after 130 years. But if we consider the additional SOC stock accumulated in the organic horizons (between 0.8 and 2 kg m-2), the total SOC stock slightly increased, although OM in organic horizons is less stabilized than mineral-bound OM. An increase of the C:N ratio in the Oi-horizon with increasing forest age (40yr: 36.9 ± 2.6; 55yr: 40.9 ± 4.1; 130yr: 42.4 ± 6.6) reflects the alteration in litter quality towards poorly decomposable compounds in older forests. In addition, preliminary results show an increase in the abundance of Gram+ (+3%) and Gram- bacteria (+6%), especially in the young (40yr) forest. Thus, the bacterial community seems to proliferate in the early succession before the fungal-dominated community takes over. Thus, the change in SOM source and quality following afforestation may not result in considerable stock changes, but results in better stability of SOM in the mineral soil.ReferencesBolli, J. C., Rigling, A., Bugmann, H. (2007). The influence of changes in climate and land-use on regeneration dynamics of Norway spruce at the treeline in the Swiss Alps. Silva Fennica, 41, 55.Hiltbrunner, D., Zimmermann, S., Hagedorn, F. (2013). Afforestation with Norway spruce on a subalpine pasture alters carbon dynamics but only moderately affects soil carbon storage. Biogeochemistry, 115, 251-266.Vesterdal, L., Ritter, E., Gundersen, P. (2002). Change in soil organic carbon following afforestation of former arable land. Forest Ecology and Management, 169, 137-147.
S-to-P receiver function analysis in the Alpine-Carpathian-Pannonian system
Authors: Kalmár Dániel , Petrescu Laura , Stipčević Josip , Balázs Attila , Kovács István János ,   the AlpArray Working Group
Published: February 2023

We perform the first, detailed S-to-P receiver function analysis to determine the depth of the lithospheric thickness in the Eastern Alps, Carpathians, and the Pannonian Basin. The Pannonian Basin hosts deep sedimentary depocentres superimposed on a complex basement structure and it is surrounded by mountain belts. The geophysical data on which investigated the lithospheric thickness was derived in the whole Pannonian Basin, are more than 20 years old. The determination and compilation of a new dataset is timely. This work is the first uniform and comprehensive S receiver function study of the Alpine-Carpathian-Pannonian system. We present our detailed workflow from the data download via quality controls to the calculations and interpretations of the S receiver functions in this study.We use data from the temporary seismic networks, the permanent stations of the Hungarian National Seismological network, as well as the permanent seismological stations in neighboring countries for the time range between 0.1.01.2002 and 31.01.2022. Owing to the dense station coverage we can achieve so far unprecedented resolution, altogether 389 seismological stations are used in this study. This enables us to provide new, hitherto unknown information about the lithospheric thickness of the region. We apply two different quality control procedures for the downloaded waveforms and the calculated S receiver functions. S receiver functions are determined by the iterative time domain deconvolution approach.We apply 1D and 2D migration of the S receiver function. We compare our result maps with map from previous geophysical investigation. We show migrated Common Conversion Point cross-sections beneath the Pannonian Basin and Carpathians, and the Eastern Alps–Pannonian Basin transition zone. Furthermore, we would like to provide new information about lithospheric thickness in the eastern part of the investigated region (e.g., Apuseni Mountains, Eastern-, Southern-Carpathians, Moesian Platform and Transylvanian Plateau).Furthermore, we jointly interpret the S receiver function results with the seismic tomography calculations of the P and S wave
Water quality responses under droughts and heatwaves in river basins worldwide
Authors: Graham Duncan , Bierkens Marc , van Vliet Michelle
Published: February 2023

River water quality is strongly affected by droughts and heatwaves worldwide. However, these effects have only been studied in a small number of river basins and regions, mainly in the US, Europe, or Australia. In this study, we analyse the large-scale responses in river water quality under droughts, heatwaves and compound events for 300,000+ water quality monitoring stations worldwide between 1980-2021. We include 16 water quality constituents in the analysis, grouped into general constituents (e.g. water temperature, salinity, dissolved oxygen), biological constituents (e.g. faecal coliform, biochemical oxygen demand) and emerging contaminants (e.g. pesticides and pharmaceuticals). Further, we assess the water quality responses to droughts and heatwaves in relation to climate, land use and level of wastewater treatment. We find a general deterioration in river water quality under droughts and heatwaves globally for most types of water quality constituents, with on average higher water temperatures (+27%), increases in salinity (+23%) and lower concentrations of dissolved oxygen (-17%). We also find that climate type, land use and level of wastewater treatment have a significant effect on the magnitude of water quality responses under droughts and heatwaves. The median increase in river temperature under compound drought-heatwaves strongly depends on climate, with for example higher increases in the Polar climate zone (+4.5°C) compared to the Tropical zone (+2.1°C). Increases in salinity under droughts are on average twice as large in irrigated regions compared to non-irrigated regions. Phosphorus and nitrogen concentrations in rivers can either increase or decrease during drought events, depending on the type of nutrient form (dissolved versus particulate) and land use (urban versus rural). Higher levels of wastewater treatment lead to a stronger reduction in faecal coliform (an indicator of pathogens) during droughts and heatwaves. Compared to previous local and regional-scale analyses, this study provides a more consistent and broader understanding of how droughts and heatwaves affect river water quality. In addition, the results from this study could be used to validate large-scale models of river water quality under droughts and heatwaves.
Managing the water-energy-food-ecosystems nexus under future climate water stress scenarios in the Ebro Basin (Spain)
Authors: Baccour Safa , Albiac Jose , Ward Frank , Kahil Taher , Esteban Encarna , Uche Javier , Calvo Elena
Published: February 2023

Increasing climate water stress and excessive and unbalanced water withdrawals by sectors are triggering substantial water depletion and environmental degradation in arid and semi-arid basins. Addressing the problem requires the integration of sectoral policies based on interdisciplinary knowledge and sustainable management strategies. The Water-Energy-Food-Ecosystems (WEFE) nexus is an innovative and comprehensive tool to guide river basin managers and stakeholders towards sustainable development goals. Several nexus approaches have been advanced for different sectors, basins, and time periods. However, none to date has presented a monthly dynamic optimization framework that includes ecosystems in order to assess the WEFE nexus for entire large basins. The contribution of this paper is to address water related challenges and highlight the gap in users engagement, by presenting the results of the cross-sectoral integration under future climate water stress (CC-2070; CC-2100), and by designing policy interventions to achieve sustainable outcomes. The WEFE nexus is analyzed for the Ebro River basin; first the analysis identifies the trade-offs and synergies among sectors and spatial locations, and then policy interventions under future climate water stress are evaluated for enhancing water, food and energy security, and for ecosystems protection. Findings provide efficient water allocation plans between competing sectors, emphasizing the importance of ecosystem services in maintaining biodiversity under future climate water stress scenarios. The policy analysis offers insights into the synergies between environmental and economic outcomes, although the costs of certain policies could be high for some groups of stakeholders. Results show that irrigation modernization, increasing reservoir storage capacity, and water trading policies provide efficient water use patterns, enlarging basin stream flows, protecting ecosystems and augmenting the private and social benefits. Sustainable agriculture and water storage management are crucial policies that promote food, water, and energy security and ecosystems protection. These critical results from interventions could help decision makers to bring about efficient water allocation planning among sectors, and advance resilience and adaptation to climate water stress. 
Intra- and inter-annual changes in isoprene emission from central Amazonia
Authors: Gomes Alves Eliane , Aquino Santana Raoni , Quaresma Dias-Junior Cléo , Botía Santiago , Taylor Tyeen , Yáñez-Serrano Ana Maria , Kesselmeier Jürgen , Lembo Silveira de Assis Pedro Ivo , Martins Giordane , de Souza Rodrigo , Duvoisin Junior Sergio , Guenther Alex , Gu Dasa , Tsokankunku Anywhere , Sörgel Matthias , Nelson Bruce , Pinto Davieliton , Komiya Shujiro , Weber Bettina , Martins Rosa Diogo ,   Cybelli Barbosa
Published: February 2023

Isoprene emissions are a key component in biosphere-atmosphere interactions, and the most significant global source is the Amazon rainforest. However, intra- and inter-annual variations in biological and environmental factors that regulate isoprene emission from Amazonia are not well understood and, thereby, poorly represented in models. Here, with datasets covering several years of measurements at the Amazon Tall Tower Observatory (ATTO) in central Amazonia, Brazil, we (1) quantified canopy profiles of isoprene mixing ratios across seasons of normal and anomalous years and related them to the main drivers of isoprene emission – solar radiation, temperature, and leaf phenology; (2) evaluated the effect of leaf age on the magnitude of the isoprene emission factor (Es) from different tree species and scaled up to canopy with intra- and inter-annual leaf age distribution derived by a phenocam; and (3) adapted the leaf age algorithm from MEGAN with observed changes in Es across leaf ages. Our results showed that the variability in isoprene mixing ratios was higher between seasons (max. during the dry-to-wet transition seasons) than between years, with values from the extreme 2015 El-niño year not significantly higher than in normal years. In addition, model runs considering in-situ observations of canopy Es and the modification on the leaf age algorithm with leaf-level observations of Es presented considerable improvements in the simulated isoprene flux. This shows that MEGAN estimates of isoprene emission can be improved when biological processes are mechanistically incorporated into the model.  
Space weathering observed on the samples returned from Ryugu
Authors: Noguchi Takaaki ,   the Hayabusa2 Initial Analysis “Sand” Team and the Hayabusa2 Initial Analysis Team Core
Published: February 2023

The samples returned from the near-Earth asteroid (162173) Ryugu by the Hayabusa2 spacecraft provide the first opportunity for laboratory study of space weathering signatures on the most abundant C-type asteroids. Many (about 60%) of them are thought to have experienced high degrees of the aqueous alteration as shown in CI and CM carbonaceous chondrites. Hayabusa2 measured in situ near-infrared reflectance spectra of Ryugu using the NIRS3 spectrometer. The shallow 2.7-µm absorption band in the spectra was interpreted as a signature of thermal metamorphism or solar radiation heating. However, all the investigations of Ryugu grains performed to date show that the Ryugu materials are genetically common to CI chondrites. The Ryugu grains are abundant in phyllosilicates (saponite and serpentine), magnetite, Fe-Ni sulfides, and carbonates. This study about the space weathering of Ryugu grains explains this discrepancy. Ryugu is exposed to the major agents of space weathering of airless bodies. However, the resultant space-weathering products are substantially different from that of the Moon and Itokawa, both of which are composed of anhydrous minerals. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Comparison of space-weathered materials with the run products of a helium irradiation experiment on non-space-weathered grains and of laser irradiation experiments of Murchison CM chondrite shows that the amorphization of phyllosilicates may be caused by solar wind irradiation and the partial melting, by micrometeoroid impact heating. Space weathering likely contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to the weakening of the 2.7-µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7-µm band can signify space weathering-induced surface dehydration, rather than bulk volatile loss.