bluuebunny/crossref_metadata_2025 huggingface dataset:
Past trends in Australian rainfall: internally generated or human-caused?
Authors: Fahrenbach Nora , Bollasina Massimo , Samset Bjorn , Cowan Tim , Ekman Annica
Published: February 2023

The expectations of the public and policymakers for accurate climate projections have grown with improvements in climate models. Internal variability, however, poses an inherent limit on climate predictability and, thus, accurate future climate projections of temperature and precipitation. This challenge is further amplified at a regional scale where internal variability can even dominate over forced anthropogenic climate change. In this study, we focused on the contribution of decadal climate variability and anthropogenic forcing (greenhouse gases and aerosols) on past precipitation changes over Australia since the 1970s. Using observational data, we find that the variance explained on decadal to multi-decadal timescales is comparable to that on sub-decadal scales across Australia, underlining the importance of examining Australian trends in the context of variability. While decadal and longer precipitation trends over Australia’s east coast are dominated by internal variability, significant drying trends in the austral winter (June to August) over southwest Western Australia and wettening trends in summer (December to February) over northwest Australia are evident. We further disentangle the influence of internal variability from that of different anthropogenic forcing agents on these trends using simulations from the CESM2 Large Ensemble and idealised anthropogenic aerosol simulations from PDRMIP (Precipitation Driver Response Model Intercomparison Project). Our findings provide additional evidence for the significant role of internal variability on regional climate change and also underline the importance of a focused dialogue between scientists, policymakers and the public to ensure realistic expectations for regional future climate projections.
Exploring the 4D scales of eco-geomorphic interactions along a river corridor using repeat UAV Laser Scanning (UAV-LS), multispectral imagery, and a functional traits framework.
Authors: Tomsett Chris , Leyland Julian
Published: February 2023

The importance of vegetation within the river corridor is well known and has been subject to a considerable body of research. The interactions between riparian vegetation and river morphology are typically complex, co-dependent, highly dynamic, and vary across both spatial and temporal scales. Vegetation diversity can typically be attributed to fluvial influences such as flood regimes and morphology, whilst simultaneously influencing the flow of water and sediment transport. However, adequately capturing the spatial and temporal complexity of vegetation characteristics has been a considerable challenge, and so a number of unresolved questions with regard to the spatial and temporal interactions of vegetation and river flow remain.Within this research, we seek to establish the relationship between vegetation presence and geomorphic response over 2 years of data collection on a 1 km stretch of the River Teme in the United Kingdom. Functional vegetation traits of different plant forms relevant to hydrological research are extracted using UAV based laser scanning and multispectral imagery. These traits are then upscaled to reach scale functional group classifications, whereby they can be compared to geomorphic change occurring throughout the reach. Our framework moves beyond typical species level classification, as vegetation is instead grouped on the potential geomorphic impact that it may have due to their characteristics. Such methods are beginning to be established in fluvial research, but are often constrained by the need for extensive ground surveying or they focus on how traits vary in response to fluvial controls.Our results show six distinct functional groups are obtained from a mix of laser scanning and imagery data, before being upscaled across the study area with a classification accuracy of 80% using random forest methods. Plant structure was subsequently used to assess spatially varying and seasonal changes in excess vegetative drag based on reference flow depths across the study site during a peak flow event. These variations could be used to assess the aggregated geomorphic response of the system based on flow conditions and vegetation type, and begin to unpick different feedbacks between them. Such methods could be used on similar river systems, to improve wider reach classifications using both airborne laser scanning and imagery, as well as in different geomorphic research where there is interactions between flows and vegetation.
Response of the ozone chemistry to changes in emissions over the Catalonia region
Authors: Badia Alba , Vidal Veronica , Ventura Sergi , Curcoll Roger , Segura Ricard , Villalba Gara
Published: February 2023

Tropospheric ozone (O3) is an important surface pollutant in urban areas with complex formation mechanisms that depend on the atmospheric chemistry composition and meteorological factors. The severe reduction in anthropogenic emissions during the COVID-19 pandemic can serve to further our understanding of the photochemical mechanisms that lead to O3 formation to provide guidance for policy aiming to reduce air pollution. In this study we use the air quality model WRF-Chem coupled with the urban canopy model BEP-BEM to investigate changes in the ozone chemistry over the Metropolitan Area of Barcelona (AMB) and its atmospheric plume northward, which is responsible for the highest number of hourly O3 exceedances in Spain. The aim is to investigate the response of the ozone chemistry to changes in precursor emissions. Results show that with the reduction in emissions: 1) the ozone chemistry formation tends to go to the NOx-limited or transition regimes, however urban areas over highly polluted areas are still in the VOC-limited regime, 2) the reduced O3 production is overwhelmed by the less nitric oxide (NO) titration resulting in a net increase of O3 concentration (up to 20 %) in the afternoon, 3) the increase in maximum O3 (up to 6%) during the lockdown could be attributed to an enhancement in the atmospheric oxidation capacity, 4) ozone and odd oxygen (Ox) maximum levels generally decrease (up to 4 %) in the relaxation period with a reduced atmospheric oxidation capacity (AOC), indicating an improvement of the air quality, and, 5) changes in ozone concentrations in the AMB contribute to the pollution plume along the S–N valley to the Pyrenees. Our results indicates that a protocol with strict measures to control NOx emissions, without cutting significantly anthropogenic sources of VOCs (e.g. for power plants and heavy industry) is essential for O3 abatement plans. In addition, our results show that the design of a mitigation strategy to reduce O3 cannot be related only on emissions reductions because ozone chemistry depends on several other factors (AOC, ozone regimes, local meteorology, transport).
Assessing the potential of low transmissivity aquifers for ATES systems: a case study in Flanders (Belgium)
Authors: Tas Luka , Simpson David , Hermans Thomas
Published: February 2023

The Member States of the European Union pledged to reduce greenhouse gas emissions by 80-95% by 2050. Shallow geothermal systems might substantially contribute by providing heating and cooling in a sustainable way through seasonally storing heat and cold in the shallow ground (<200m). When the minimum yield to install a cost-effective aquifer thermal energy storage (ATES) system cannot be met, borehole thermal energy storage (BTES), relying mostly on the thermal conductivity of the ground, is proposed. However, for large-scale applications, this requires the installation of hundreds of boreholes which entails a large cost and high disturbance of the underground. In such cases, ATES systems can nevertheless become interesting. In this contribution, we present a case study performed on a Ghent University campus, where the feasibility of ATES in an area with a low transmissivity was determined. The maximum yield of the aquifer was estimated  at 5 m³/h through pumping tests. Although this low yield was attributed to the fine grain size of the aquifer, membrane filtering index tests and long-term injection tests revealed that the clogging risk was limited. A groundwater model was used to optimize the well placement while limiting the risk of interactions between the wells resulting in a thermal breakthrough or flooding at the surface. It was shown that a well arrangement in a checkerboard pattern was most effective to reach these objectives. Hence, for large-scale projects, a minimal CO2 output might be reached using a (more cost-effective) ATES system even in low permeable sediments.
Modeling daily urban temperature fields using land use regression approaches
Authors: Burger Moritz , Gubler Moritz , Brönnimann Stefan
Published: February 2023

Detailed knowledge about the intra-urban air temperature variability within a city is crucial for the implementation of adaptation strategies to counteract the negative effects of urban heat stress. Various methods to model urban-rural temperature differences exist, but they often only cover certain periods (heatwave, hot day) or meteorological conditions (sunny and calm) due to computational limitations or limited data availability. Land use regressions, which are usually based on fine scaled measurements and high resolution spatiotemporal data, are one promising method to overcome those limitations and to conduct daily urban temperature fields.In the city of Bern, Switzerland, a very dense urban temperature network (about 1 station per 1.5 km2) is operated since summer 2018. With that detailed information on temperature and publicly available land use and meteorological data, different land use regression types with a differing degree of complexity were tested in the recent past. One main outcome of the application of the method in Bern is an urban temperature dataset that covers the temperature distribution of all nights of the metropolitan area of the summers 2007 to 2022 with a resolution of 50 meters. In this talk, we would like to present the different models applied in Bern, analyze the potential of land use regression approaches in urban climate studies, and discuss possible applications of the dataset regarding urban planning and heat stress studies.
Employing Optical Lightning Data to identify lightning flashes associated to Terrestrial Gamma-ray Flashes
Authors: Köhn Christoph , Heumesser Matthias , Chanrion Olivier , Reglero Victor , Østgaard Nikolai , Christian Hugh , Lang Timothy , Blakeslee Richard , Neubert Torsten
Published: February 2023

Terrestrial gamma-ray flashes (TGFs) are bursts of energetic X- and gamma-rays emitted from thunderstorms and observed by the Atmosphere-Space Interactions Monitor (ASIM) mounted onto the International Space Station (ISS) detecting TGFs and optical signatures of lightning. ISS-LIS (Lightning Imaging Sensor) detects lightning flashes allowing for simultaneous measurements with ASIM. Whilst ASIM measures ~300-400 TGFs per year, ISS-LIS detects ~ 106 annual lightning flashes giving a disproportion of four orders of magnitude. Hence, based on the temporal evolution of lightning flashes and their spatial pattern, we present an algorithm to reduce the number of flashes potentially associated with TGFs by ~90%, and we use the ASIM TGF list to ensure that the resulting flashes are those associated with TGFs and thus benchmark our algorithm. We will compare how the radiance, footprint size and the global distribution of lightning flashes of the reduced set relates to the average of all measured lightning flashes. Finally, we will present a parameter study of our algorithm and discuss which parameters can be tweaked to maximize the reduction efficiency whilst keeping those flashes associated to TGFs. In the future, this algorithm will hence facilitate the search for TGFs in a reduced set of lightning flashes.
Building Earthquake Damage Mapping from Post-event PolSAR Data Based on Polarimetric Decomposition and Texture Features
Authors: Zhai Wei , Bi Yaxin , Zhu Guiyu , Du Jianqing
Published: February 2023

Buildings are the main places for people to live and work as well as the most important economic entities in urban areas. The collapse of buildings caused by destructive earthquakes often caused severe casualties and economic losses. After an earthquake, the assessment of building damage is one of the most important tasks in earthquake emergency response. Accurate assessment of building damage will be essential in making plans of emergency responses. Four-Polarimetric Synthetic Aperture Radar (PolSAR) data has the advantages of Synthetic Aperture Radar (SAR) imaging that is not occluded by sunlight and clouds, it also contains the most abundant information of four polarimetric channels. Due to the large amount of information in PolSAR data, only a single post-earthquake PolSAR image can be used to identify building damage of post-earthquake. It is easy to overestimate the number of collapsed buildings and the damage degree of earthquakes only using a traditional polarimetric decomposition method for PolSAR data. The layout of urban buildings can be diverse. Buildings can stand in parallel in typical SAR imaging with strong scattering features, there are also some oriented standing buildings with lower scattering intensity and with similar scattering characteristics of collapsed buildings, thus these oriented buildings are often misconstrued as collapsed buildings. In this study, we propose a new texture feature, namely mean standard deviation (MSD) index of texture feature based on Gray-level Co-occurrence Matrix (GLCM), to solve the overestimate of damage of buildings, which are caused by earthquakes. The MSD index can be defined as follows:              (1)where ISAR is the intensity image of PolSAR data, and mean (•) and variance (•) represent the calculation of mean values and variance values based on GLCM for (•), respectively. Meanwhile, based on the improved Yamaguchi four-component decomposition method and the MSD index parameter, we develop a solution to identify the damage of buildings only using a single post-earthquake PolSAR image. The Ms7.1 Yushu earthquake, which occurred in Yushu County of China on 14th April, 2010, is used as a study case to carry out the experiment with 75000 undamaged and damaged building samples. With the proposed method, the experimental results show 82.43% identification accuracy for damaged buildings and 80.30% identification accuracy for undamaged buildings. Compared with the traditional polarimetric decomposition method, 66.89% standing buildings are successfully isolated from the mixture of collapsed buildings. Therefore this new method has greatly improved the accuracy and reliability of extracting damage information of buildings.
Soil carbon and nitrogen responses to global change are informed by soil organic matter fractions
Authors: Rocci Katherine S. , Cotrufo M. Francesca
Published: February 2023

As the largest terrestrial carbon (C) pool, the feedbacks of soil C to global environmental change have significant implications for our future climate. It is increasingly recognized that studying solely bulk soil C and nitrogen (N) responses to global change is not sufficient. Because different fractions of soil organic matter (SOM) have distinct controls, they likely respond differently to global changes. To investigate the responses of SOM fractions to global change we must combine data synthesis with mechanistic experiments. We investigated the responses of particulate and mineral-associated organic matter (POM and MAOM) to global change through a global meta-analysis and an increased precipitation experiment. In our meta-analysis we found that POM was more strongly influenced by global change than MAOM and that these fractions responded uniquely to global changes. In particular, increased precipitation caused opposing, but non-significant, responses of POM and MAOM C (decrease and increase, respectively) when investigated with meta-analysis. In investigating POM and MAOM responses to an increased precipitation experiment, we find greater support for changes in plant biomass and diversity driving changes in SOM fractions than changes in microbial necromass. Unique, statistically stronger, and plant- and microbially-informed responses of SOM fractions as compared to bulk SOM suggest these fractions are useful for understanding SOM responses to global change. Altogether, our work provides strong evidence that fractionating SOM into POM and MAOM will help determine whether soil C will feed back positively or negatively to climate change.
An unbiased spatiotemporal fusion approach to generate daily 100 m spatial resolution land surface temperature over a continental scale
Authors: Yu Yi , Renzullo Luigi , Tian Siyuan , Malone Brendan
Published: February 2023

High spatial resolution land surface temperature (LST) (<= 100 m) has a considerable significance for small scale studies like agricultural applications and urban heat island studies. Originally developed for optical data, spatiotemporal fusion methods, such as the widely used Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) and the Enhanced STARFM (ESTARFM), are gradually becoming promising approaches to generate high resolution thermal variables but still have shortcomings, such as an invalid assumption in thermal fields and the accumulation of systematic biases. Hence, we proposed a variant of the ESTARFM algorithm, referred as the unbiased ESTARFM (ubESTARFM), aiming to better accommodate the spatiotemporal approach to thermal studies. We evaluated the results derived from our method and the typical ESTARFM against both in-situ LST and the ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) LST over a continental scale of Australia. The results show that the ubESTARFM has a bias of 2.55 K, unbiased RMSE (ubRMSE) of 2.57 K, and Pearson correlation coefficient (R) of 0.95 against the in-situ LST over 11290 samples at 12 sites, all of which are significantly better than that of the ESTARFM, with a bias of 4.73 K, ubRMSE of 3.80 K and R of 0.92. In the cross-satellite comparison, the ubESTARFM LST has a bias of -1.69 K, ubRMSE of 2.00 K, and R of 0.70 over 43 near clear-sky scenes, while the ESTARFM LST has a bias of 1.79 K, ubRMSE of 2.68 K, and R of 0.59. Overall, the ubESTARFM is able to avoid the accumulation of systematic bias, considerably reduce the deviation of uncertainty, and maintain a good level of correlation with validation datasets compared to the typical ESTARFM algorithm. It is a promising method to integrate reliable numeric values from coarse resolution LST and spatial heterogeneity from fine resolution LST, and may be further coupled with energy balance or radiative transfer models to better enable farm- or regional-scale water management strategy or decision making.
Soil erosion susceptibility assessment in Mediterranean areas by means of soil quality. A test in the Guadalmedina watershed (Málaga,Spain)
Authors: González-Pérez Javier , Sillero-Medina José Antonio , Espinosa-Muñoz Julia , Ruiz-Sinoga José Damián
Published: February 2023

Soil erosion is one of the most relevant environmental problems facing society today. Climate change has a direct impact on these processes through a feedback loop, especially in the Mediterranean region, where the situation is conceived as one of extreme fragility. The increase in extreme rainfall and temperature events, together with differential human land use, are leading to an intense degradation of Mediterranean soils. Therefore, it is essential to determine the levels of susceptibility of the landscape to erosion processes to create new strategies to improve the management of the land and reduce the potential risks that may exist. Specifically, this work has focused on the Guadalmedina watershed, in Malaga (Spain), which is characteristic of the current dynamics of the Mediterranean landscape. For this purpose, a soil quality index based on a multi-criteria analysis of different soil indicators (water, physical and organic) has been applied in this study, using a total of 132 soil samples measured in the laboratory. In addition, the results of this analysis have been contrasted with soil erosion values derived from the application of RUSLE model. From this process, those slopes and fields with the highest water erosion risk values have been identified at the most detailed scale. In general, the lowest soil erosion rates are found in those areas where soil quality indicators show optimal values. Furthermore, the results obtained indicate that organic soil indicators are decisive in the processes of water erosion in the Mediterranean area.
Importance of atmospheric feedbacks in simulating the seasonal cycle of the Antarctic sea ice and its response to perturbations.
Authors: Goosse Hugues , Allende Contador Sofia , Bitz Cecilia M. , Blanchard-Wrigglesworth Edward , Eayrs Clare , Fichefet Thierry , Himmich Kenza , Huot Pierre-Vincent , Klein François , Marchi Sylvain , Massonnet François , Mezzina Bianca , Pelletier Charles , Roach Lettie , Vancoppenolle Martin , van Lipzig Nicole P.M.
Published: February 2023

The seasonal cycle of the Antarctic sea ice extent is largely controlled by the evolution of the insolation received at the top of the atmosphere. However, sea ice processes and feedbacks with the ocean and the atmosphere can modulate this seasonal cycle. Here, the atmospheric feedbacks are quantified in a series of idealized sensitivity experiments performed with an eddy-permitting (1/4°) NEMO-LIM3 Southern Ocean configuration, including a representation of ice shelf cavities, in which the model was either driven by an atmospheric reanalysis or coupled to the COSMO-CLM2 regional atmospheric model. In these experiments, sea ice thermodynamics and dynamics as well as the exchanges with the ocean and atmosphere are strongly perturbed. This perturbation is achieved by modifying snow and ice thermal conductivities, the vertical mixing in the ocean top layers, the effect of freshwater uptake/release upon sea ice growth/melt, ice dynamics and surface albedo. We show that the changes in surface heat fluxes are very different between the configurations driven by the reanalysis and those coupled to the atmosphere. Atmospheric feedbacks enhance the response of the modelled winter ice extent to any of the perturbed processes, and the enhancement is strongest when the albedo is modified. The response of sea ice volume and extent to changes in entrainment of subsurface warm waters to the ocean surface is also greatly amplified by the coupling with the atmosphere. By contrast, the atmospheric feedbacks can damp the impact of the perturbations affecting the heat conductivity through sea ice.
Rapid Intensification and Rapid Weakening of Tropical Cyclones, as represented by the CMCC-CM3 Climate Model
Authors: Scoccimarro Enrico , Peano Daniele
Published: February 2023

Rapid intensification/weakening (RI/RW) refers to a significant increase/decrease in tropical cyclone (TC) intensity over a short period of time. A TC can also undergo multiple RI/RW events during its lifetime, and these events pose a significant challenge for forecasting TC activity. In fact, RW is one major source of large intensity forecasting errors as well as RI. These processes can be associated to particular large-scale conditions, both in terms of atmospheric drivers - such as vertical wind shear or dry air intrusion - and oceanic drivers - such as sea surface temperature (SST) gradient.In this work we aim to verify the ability of the new CMCC-CM3 model (a preliminary version of the General Circulation Model that will take part to the 7th Coupled Model Intercomparison Project - CMIP7 effort) in representing Tropical Cyclone activity with a particular focus on RI and RW. The simulations used in this work have been provided within the EU project BlueAdapt at a 25km horizontal resolution in atmosphere and ocean components, ensuring the representation of realistic TCs both in terms of spatial variability and intensity. Less agreement is found in representing RI/RW timing and duration, but better results are obtained, compared to the previous version of the model CMCC-CM2. The role of the ocean in determining RI and RW is also investigated.
A multi-criteria decision-making tool to identify optimal locations for PV-geothermal systems for Heating and cooling in industrial areas.
Authors: Ramos Escudero Adela , García Gil Isabel , Molina Garcia Angel , García Cascales Maria del Socorro
Published: February 2023

The consequences of climate change and the urgent need in the EU to produce our self-clean energy from renewable resources are rapidly changing the rules. To meet the goal to produce our energy with 45% from the renewable resource for 2030, the diversification of the renewable resources to use to produce our energy is compulsory, and not only from solar and wind. Renewable energy hybrid systems are proven to be the most energy efficient and emissions savers as they take most of the natural resources intermittently, which is usually a drawback for a single renewable energy system.Spain (along with Portugal) accounts for the highest yearly radiation rates, which energy is mainly used to produce electricity. Moreover, in Spain, 31% of the total energy is consumed by industry eminently consumed in Industrial parks, considered energy-consumers hotspots. Therefore, a hybrid PV-geothermal system is proposed as a more efficient system to produce heat and cold from renewables for the industry, both for industrial processes and heating and cooling. However, Spain shows very different orography and climate conditions along its territory, provoking different performance ratios of the proposed hybrid systems. Among the most influential factors affecting these systems' environmental and economic performance are the yearly solar irradiation, the energy demand, and the geothermal resource potential that differ in a spatial component.In this work, a Multicriteria Decision Making (MCDM) tool is created and applied to spatially assess the performance of these systems and identify the optimal zones for PV-geothermal hybrid facilities based on the main spatial environmental factors. The tool is applied in high energy industrial demand areas from the new "Heat map of Spain" (Ecology Transition and demographic challenge Ministry of Spain) and is developed in a GIS environment. The main results expected are the performance indicators of PV-geothermal systems in Spain for the industrial sectors and the selection of the optimal zones of these systems in Spain based on the energy demand, solar irradiation, and geothermal potential.
Oil spill modeling assessment of the 2021 Syrian oil spill using SAR imagery and multi-forcing forecasts
Authors: Keramea Panagiota , Kokkos Nikolaos , Zodiatis George , Sylaios Georgios , Coppini Giovanni , Peña Juan , Benjumeda Herreros Pablo , Sepp-Neves Antonio Augusto , Lardner Robin , Liubartseva Svitlana , Soloviev Dmitry , Scuro Matteo , Nicolaidis Andreas , Viola Fabio
Published: February 2023

Oil spills in the marine field can have serious consequences for ecosystems, the environment, public health, the economy, and communities. Thus, following the spillage of 12,000 tons of crude oil from the fuel tanks of the Baniyas power plant in summer 2021, daily operational oil spill predictions were carried out  to predict the spill transport and fate in the Levantine basin, Eastern Mediterranean, supporting the Regional Marine Pollution Emergency Response Centre for the Mediterranean  (REMPEC) and national response agencies. High frequency met-ocean forecasting data from the Copernicus Marine Monitoring Service (CMEMS), the European Centre for Medium-Range Weather Forecasts (ECMWF), and regional models (SKIRON, CYCOFOS) were used, along with satellite-derived SAR data from EMSA-CSN and optical images from ESA to initiate the oil spill models and to determine the evolution, the extent and coverage of the spillages. Two up-to-date and advanced Lagrangian particle-tracking models, OpenDrift and MEDSLIK were used to assess and evaluate the oil spill predictions, generated by the aforementioned models, under a variety of met-ocean forcings and configurations, indicating the significant role of the high-resolution met-ocean data in the evolution of the oil spill trajectory. A number of quantitative metrics were used to evaluate the ability to adequately reproduce the oil spill spreading, by comparing the SAR observed oil spillages against the models results, in more detail.
Study of the effect of compaction on the hydrodynamic properties of a loamy sand soil for precision agriculture
Authors: Mbarki Yasmin , Gumiere Silvio José
Published: February 2023

Compaction of agricultural soil negatively affects its hydraulic proprieties, leading to water erosion and other negative effects on the quality of the environment. This study focused on the effect of compaction on soil hydrodynamic properties under unsaturated and saturated conditions using the Hydraulic Property Analyzer (HYPROP) system. We studied the impact of five levels of compaction among loam sand soils collected in a potato crop field in northern Québec, Canada. Soil samples were collected, and the soil bulk densities of the artificially compacted samples were developed by increasing the bulk density by 0% (C0), 30% (C30), 40% (C40), 50% (C50), and 70% (C70). First, the saturated hydraulic conductivity of each column was measured using the constant-head method. Soil water retention curve (SWRC) dry-end data and unsaturated hydraulic conductivities were obtained via the implementation and evaluation of the HYPROP evaporation measurement system and WP4-T Dew Point PotentioMeter equipment (METER group, Munich, Germany). Second, the soil microporosity was imaged and quantified using the micro-CT-measured pore-size distribution to visualize and quantify soil pore structures. The imaged soil microporosity was related to the saturated hydraulic conductivity, air permeability, porosity and tortuosity measured of the same samples.  Our results supported the application of the Peters–Durner–Iden (PDI) variant of the bimodal unconstrained van Genuchten model (VGm-b-PDI) for complete SWRC estimation based on the root mean square error (RMSE). The unsaturated hydraulic conductivity matched the PDI variant of the unconstrained van-Genuchten model (VGm-PDI) well. Finally, the preliminary results indicated that soil compaction could strongly influence the hydraulic properties of soil in different ways. The saturated conductivity decreased with increasing soil compaction, and the unsaturated hydraulic conductivity changed very rapidly with the ratio of water to soil. Overall, the HYPROP methodology performed extremely well in terms of the hydraulic behavior of compacted soils.
Lower Ionospheric variation over Europe during the tectonic activity in the area of Thessaly, Greece on March of 2021.
Authors: Contadakis Michael E. , Arabelos Demeter N. , Christos Pikridas , Bitharis Stylianos , Scordilis Emmanuel
Published: February 2023

This is one of a series of papers in which  we investigate the Lower ionospheric variation on the occasion of intense tectonic activity.In the present paper, we investigate the TEC variations during the intense seismic activity in Thessaly, on March 2021 over Europe. The Total Electron Content (TEC) data are been provided by the  Hermes GNSS Network managed by GNSS_QC, AUTH Greece, the HxGN/SmartNet-Greece of Metrica S.A, and the EUREF Network. These data were analysed using Discrete Fourier Analysis in order to investigate the TEC turbulence. The results of this investigation indicate that the High-Frequency limit fo of the ionospheric turbulence content, increases as aproaching the occurrence time of the earthquake, pointing to the earthquake epicenter, in accordane to our previous investigations. We conclude that the Lithosphere Atmosphere Ionosphere Coupling, LAIC, mechanism through acoustic or gravity waves could explain this phenomenology. Keywords: Seismicity, Lower Ionosphere, Ionospheric Turbulence, Brownian Walk, Aegean area.
The Footprint of Growing Stratospheric Transport Contribution in Tropospheric Ozone
Authors: Ma Xiaodan , Huang Jianping , Sprenger Michael , Hegglin Michaela Imelda , Jöckel Patrick , Zhao Tianliang
Published: February 2023

The long-term ozone changes in the middle to upper troposphere, of importance to climate radiative forcing and setting the baseline for tropospheric ozone pollution, are not well quantified from observations in East Asia. In this study, three decades of observations from ozone soundings are examined with meteorological reanalysis data and climate model simulations to characterize regional features in tropospheric ozone and investigate their driving factors along the northwestern Pacific coastal region. A rapid increase in ozone is observed in the middle to upper troposphere over Naha (26 oN), Tsukuba (36 oN), and Sapporo (43 oN) in the warm season during 1990‒2020. Coincidentally, tongue-shaped hotspots with high tropospheric ozone extending from the stratosphere occur during the warm season. The timing for these ozone hotspots shows a time lag from late spring to summer with the increasing latitude of the observation sites. Intensified stratospheric intrusion (i.e., tropopause folding) events and enhanced buildup of ozone abundance in the lowermost stratosphere (likely driven by climate change) are the key factors causing the large increase over this region. With the aid of the chemistry climate model EMAC, the enhanced downward transport of stratospheric ozone into the troposphere is revealed by a surge in the stratospheric ozone tracer in the troposphere.
I'm a Survivor : Acacia trees ability to cope with extremely hot and dry environments
Authors: Uni Daphna , Klein Tamir , Winters Gidon , Sheffer Efrat
Published: February 2023

Among living tree species, Acacia raddiana (Savi) and Acacia tortilis (Forssk), species of the legume family, populate some of the hottest and driest places on Earth. Our research investigates the physiological processes underlying the unique survival of trees in extreme environmental conditions. We measured Acacia trees in their natural habitat together with a controlled experiment under scenarios of drought and low N on a lysimeters system to unravel their water use strategies and growth dynamics. In the field, temperature positively influenced the growth rate of the trees, daily and annual gas-exchange curves showed higher gas exchange during noon and in summer, when temperature and radiation are maximal (44°C, 2000 µmol m-2 s-1), and the air is dry (21% RH). Furthermore, in the controlled experiment, Acacia saplings keep transpiring water (180 g per day), especially at noontime (0.08 gwater/gplant/ min), and therefore continue growing in low soil water content of 5%. These findings suggest a strong potential for acacia trees to contribute to ecosystem carbon sequestration in warming and drying climates.
Quantifying effects of Indian aerosol emissions on regional aerosol abundances, energy balance, and health impacts, using a novel national emission inventory
Authors: Lund Marianne T. , Sahu Saroj K. , Mangaraj Poonam , Samset Bjørn H. , Chowdhury Sourangsu , Myhre Gunnar , Johansen Ane N.
Published: February 2023

After years of rapid growth, India has become a hotspot for emissions of aerosols and their precursors, recently surpassing China in terms of magnitude of SO2 emissions. The resulting high air pollution levels influence climate through interactions with solar radiation, clouds, and the hydrological cycle, and pose one of the greatest environmental threats to public health. Model estimates of these impacts are influenced by the substantial spread that exists between current emission inventories, in terms of both trend and magnitude. Activity and fuel data is heterogeneous and can be challenging to compile, and many emission sources are highly region specific. Hence, inventories need to be based on up-to-date national statistics and detailed sectoral information.Here we use one such inventory for Indian anthropogenic emissions, the recently developed, bottom up SNEII (Sabe National Emission Inventory for India) dataset to simulate and evaluate regional air pollution levels for 2018. SNEII includes a more detailed spatial allocation of point sources of emissions and sectoral disaggregation than many global inventories. The results are compared to estimates using the Community Emission Data System (CEDS) emissions, version 2021, also placing them in the context of the trend over the past decades. For most species, SNEII estimates higher emissions, and we explore the resulting impact of these differences on simulated aerosol abundances, as well as implications for radiative forcing and premature mortality. Finally, we quantify the sectoral contribution to air pollution with a finer breakdown than previously provided, including sectors unique for Indian/South Asian region.  
Study of the origin of soil 222Rn and 220Rn activities in Taylor Valley, Antarctica.
Authors: Ruggiero Livio , Sciarra Alessandra , Tuccimei Paola , Galli Gianfranco , Mazzini Adriano , Mazzoli Claudio , Tartarello Maria Chiara , Florindo Fabio , Wilson Gary , Mattia Martina , Tositti Laura , Morozzi Pietro , Benà Eleonora , Bigi Sabina , Sassi Raffaele , Anderson Jacob , Ciotoli Giancarlo
Published: February 2023

Warming global climate threatens the stability of the polar regions and may result in cascading broad impacts. Studies conducted on permafrost in the Arctic regions indicate that these areas may store almost twice the carbon currently present in the atmosphere. Therefore, permafrost thawing has the potential to magnify the warming effect by doubling the more direct anthropogenic impact from burning of fossil fuels, agriculture and changes in land use. Permafrost thawing may also intensify the Rn transport due to the increase of fluid saturation and permeability of the soil. A detailed study of 222Rn and 220Rn activity levels in polar soils constitutes a starting point to investigate gas migration processes as a function of the thawing permafrost. Although several studies have been carried out in the Arctic regions, there is little data available from the Southern Hemisphere. The Italian – New Zealand “SENECA” project aims to fill this gap and to provide the first evaluations of gas concentrations and emissions from permafrost and/or thawed shallow strata of the Taylor Valley, Antarctica. Taylor Valley is one of the few Antarctic regions that are not covered by ice and therefore is an ideal target for permafrost investigations. Results from our field measurements highlight very low values for 222Rn and higher values for 220Rn, suggesting a shallow source. Usually the measured 222Rn activity values are controlled by the radionuclide content in the soil, the temperature of the soil, the porosity of the soil, and the water content. We applied the Akerblom formula to calculate the radon at equilibrium with the activity concentration of the 226Ra on the collected soil samples, and the presence of 222Rn amounts higher than those naturally produced by the outcropping sediments is detected. These results demonstrate the presence of preferential gas pathways through the permafrost from a deep source. It is the first time that this type of study has been performed in Antarctica and can make a significant contribution to understanding the melting permafrost processes and its implications for the environment. This dataset also represents an important benchmark for future measurements to track the melt progress of Antarctic permafrost.
The Qinghai-Tibet Plateau may have already shifted to carbon source: Evidence from OCO-2 satellite XCO2 observations
Authors: He Wei , Jiang Fei , Ju Weimin , Wang Hengmao , Nguyen Ngoc Tu , Chen Jing M.
Published: February 2023

As one of the most sensitive regions to climate change on the Earth's surface, the Qinghai-Tibet Plateau is experiencing lasting warming, which has been evidenced to enhance surface carbon uptake but also could lead to carbon emission due to accelerated permafrost degradation and ecosystem respiration. Due to the difficulties of limited observations and imperfect modeling techniques, whether the Qinghai-Tibet Plateau is a carbon sink or source has been an ongoing debate. The recent satellite XCO2 Observations could provide some useful constraints on the carbon budget in this region.  Here, based on the recent OCO-2 XCO2 observations and the inversion results from the OCO-2 v10 MIP, we estimated the net biome carbon fluxes for the Qinghai-Tibet Plateau. Our results suggest that this region has become a carbon source (around -0.10 PgC/year) already, which is supported by an upscaling estimate with intensified eddy covariance flux measurements over China. Meanwhile, we found this carbon source signal is not detected by either in-situ CO2 inversions or terrestrial biosphere model simulations. Currently, although some studies based on flux measurements report this region is a carbon sink and even keeps increasing recently, many others hold opposite viewpoints about it. Our result provides an important piece of evidence supporting that the Qinghai-Tibet Plateau becomes a carbon source, albeit additional evidence is needed, especially from in-situ CO2 observations and aerial CO2 observations (e.g., by aircraft, unmanned aerial vehicle, and AirCore). In principle, atmospheric CO2 measurements could provide a more complete picture of the carbon budget in this region compared to discrete and limited eddy flux measurements. In the future, enhanced in-situ and aerial CO2 observations are expected to disentangle the puzzle of this carbon budget issue in this region.
Evaluation and projection of global terrestrial near-surface wind speed based on CMIP6 GCMs
Authors: Shen Cheng , Zha Jinlin , Li Zhibo , Azorin-Molina Cesar , Minola Lorenzo , Chen Deliang
Published: February 2023

We evaluate the performance of Coupled Model Intercomparison Project Phase 6 (CMIP6) models in simulating the observed global terrestrial near-surface wind speed (NSWS) and project its future changes under three different Shared Socioeconomic Pathways (SSPs). Results show that the CESM2 has the best ability in reproducing the observed NSWS trends, although all models examined are generally not doing well. Based on projections of CESM2, the global NSWS will decrease from 2021 to 2100 under all three SSPs. The projected NSWS declines significantly over the north of 20°N, especially across North America, Europe, and the mid-to-high latitudes of Asia; meanwhile, it increases over the south of 20°N. Under SSP585, there would be more light-windy days and fewer strong-windy days than those under SSP245, which leads to a significant global NSWS decline. Robust hemispheric-asymmetric changes in the NSWS could be due to the temperature gradient in the two hemispheres under global warming, with −1.2%, −3.5%, and −4.1% in the Northern Hemisphere, and 0.8%, 1.0%, and 1.5% in the Southern Hemisphere, for the near-term (2021–2040), mid-term (2041–2060), and long-term (2081–2100), respectively.
Understanding the impact of recent crises on the hydropolitics and food security of the Nile River Basin: a discourse analysis
Authors: Castelli Giulio , Bréthaut Christian
Published: February 2023

The Nile is the longest river in Africa and has historically been considered the longest river in the world, north-flowing into the Mediterranean Sea in north-eastern Africa. A research gap is still represented by the analysis of how discourses on food security may have shaped water management, power relationships, and hydro-social dynamics.  The present contribution will focus on three main countries (Egypt, Ethiopia, and Sudan), with a particular focus on some emblematic events that happened in the last years, mainly related to the development of the Grand Ethiopian Renaissance Dam, the Ukrainian War and its impact on food security, and the recognition of the impacts of Climate Change at the Global level.Discourse analysis is developed on a database of official documents generated in recent United Nations General Assemblies and Security Councils, based on the framework developed by Bréthaut et al., 2021. Discourses are defined as formal ways of thinking that can be expressed through language. They represent a way of organizing knowledge that structures the constitution of societal relations through the collective understanding of discursive logic and the acceptance of the discourse as a fact. The analysis of discourses created by different actors involved in a hydropolitical dispute, and the power of such discourses in shaping concepts and practices related to water management, can highlight and identify how hydropolitics evolve, and when, why, and how we can expect opportunities for cooperation, or threats of conflicts over water resources. Bréthaut, C., Ezbakhe, F., McCracken, M., Wolf, A., & Dalton, J. (2021). Exploring discursive hydropolitics: a conceptual framework and research agenda. International Journal of Water Resources Development.
Thermal niche determines marine assemblage change during Early Jurassic warming pulses
Authors: Reddin Carl , Landwehrs Jan , Mathes Gregor , Saupe Erin , Ullmann Clemens , Feulner Georg , Aberhan Martin
Published: February 2023

Marine assemblages are expected to undergo substantial reorganization under anthropogenic climate change but some species may be better situated to track their preferred conditions. Assemblage vulnerability can thus be indicated by the thermal niches of its component species. However, the link between this vulnerability and extinction risk of its species is unclear and cannot yet be tested with modern species since widespread climate-driven extinctions are not yet manifest. To address this gap, we inferred fossil species’ thermal niches based on observed distributions on paleoclimate maps over the hyperthermal pulses of the Late Pliensbachian to Early Toarcian. We tested whether species extirpated from fossil invertebrate assemblages after warming, alongside those species that went extinct, were most likely from the pool of species that could not maintain upper thermal safety margins, in contrast to assemblage immigrants. The fossil record has the potential to reveal unique information about natural system responses to climate change. We discuss how much can it tell us about marine ectotherm vulnerability to extinction under climate change.
Solar Cycle Variation of Energetic Neutral Atoms in the Subsolar Magnetosheath based on IBEX Observations
Authors: Sokol Justyna M. , Starkey Michael , Dayeh Maher , Fuselier Stephen , Petrinec Steve , McComas David , Schwadron Nathan , Szalay Jamey , Ogasawara Keiichi
Published: February 2023

The in-ecliptic solar wind influences the boundaries of the Earth’s magnetosphere, e.g., by controlling the distances of the magnetopause and bow shock. The exospheric neutral hydrogen has been measured up to the Moon’s orbit. The charge exchange between the solar wind protons and the neutral geocoronal hydrogen creates an energetic neutral atom (ENA). The field-of-view of the IBEX-Hi instrument onboard the Interstellar Boundary Explorer (IBEX) encompasses various portions of the Earth’s magnetosphere during the year, including the subsolar point. Recently, Sokół et al. 2021 (ApJ 922 250) reported periodic, solar cycle enhancements of the solar wind dynamic pressure. We study the solar cycle evolution of the H ENA flux in the subsolar magnetosheath based on the IBEX measurements. We observed an enhancement of the ENA flux after the maximum of solar activity. We also analyze how the ENA flux varies with the solar wind parameters. We observe positive correlations with the solar wind dynamic pressure in the energy range from 0.7 to 4.3 keV and also opposite variations in correlation coefficients between the ENA flux and the solar wind speed and density.