bluuebunny/crossref_metadata_2025 huggingface dataset:
Elastic full-wave field simulation in 3D tunnel space using a variable staggered-grid finite-difference method in cylindrical coordinates
Authors: Zheng Yunpeng , Cheng Fei , Liu Jiangping
Published: February 2023

Tunnel advance detection technology is an important method for determining the structure of a complex geological body in front of the tunnel face. Among the tunnel advance detection technologies, the seismic method is one of the most accurate methods with long detection distances. In seismic tunnel advance detection, the cylindrical configuration aggravates the complexity of the wave field in the tunnel space and significantly influences the accuracy of the detection results. Thus, it is crucial to simulate an accurate seismic full-wave field of the tunnel space and to understand the propagation and wave-field characteristics of individual seismic waves for seismic tunnel advance detection. Usually, in 3D Cartesian coordinates, the tunnel wall is approximated with a staircase boundary, but it is not sufficiently accurate in shape and generates numerical dispersion in the simulation, especially in the presence of surface waves. Therefore, we developed a variable staggered-grid finite-difference method in cylindrical coordinates to simulate the elastic full-wave field in a 3D tunnel space. Setting free-surface boundary conditions solves the propagation of surface waves on the tunnel wall and face. The free-surface boundary condition was validated by comparing the simulated seismic records with the finite element method. The interference of the instability and discontinuity of the pole axis in the seismic wave field simulation was eliminated using our method. Using this scheme, we simulated the elastic full-wave field of three geological bodies in front of the tunnel face, including the vertical interface, inclined interface, and karst cave. The results of the three models show that the excitation near the tunnel face is more conducive to the detection of geological bodies. Compared with the simulation results in Cartesian coordinates, the results in cylindrical coordinates show that numerical dispersion is negligible and conclude that a higher signal-to-noise ratio and more accurate seismic wave field can be simulated with cylindrical coordinates in the tunnel space. The new method can also be used as an accurate elastic wave propagator for reverse-time migration and full-waveform inversion under tunnel-observing geometries. Our simulation method provides theoretical and practical guidance for analyzing and interpreting seismic wave fields in tunnel advance detection.
Astronomical calibration of the Paleocene-Eocene Thermal Maximum on the Atlantic Coastal Plain
Authors: Li Mingsong , Bralower Timothy , Kump Lee , Self-Trail Jean , Zachos James , Rush William , Robinson Marci
Published: February 2023

The chronology of the Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) remains disputed, hampering complete understanding of the possible trigger mechanisms of this event. Here we present an astrochronology for the PETM carbon isotope excursion from Howards Tract, Maryland a paleoshelf environment, on the mid-Atlantic Coastal Plain. Statistical evaluation of variations in calcium content and magnetic susceptibility indicates astronomical forcing was involved and the PETM onset lasted about 6 kyr. The astrochronology and Earth system modeling suggest that the PETM onset occurred at an extreme in precession during a maximum in eccentricity, thus favoring high temperatures, indicating that astronomical forcing could have played a role in triggering the event. Ca content data on the paleo-shelf, along with other marine records, support the notion that a carbonate saturation overshoot followed global ocean acidification during the PETM.
A strong pulsing nature of negative recoil leaders accompanied by regular trains of microsecond-scale pulses
Authors: Kolmašová Ivana , Scholten Olaf , Santolik Ondřej , Hare Brian M. , Liu Ningyu Y. , Dwyer Joseph R. , Lán Radek
Published: February 2023

A presence of regular sequences of microsecond-scale pulses has been occasionally reported in the lightning literature for more than forty years. Due to a fine time resolution of modern electromagnetic receivers, the properties of these pulse trains are now well described. Nevertheless, the conditions for their occurrence are still not understood, and the information needed for their proper modelling is not sufficient.  To contribute to this effort, we report for the first time properties of negative recoil stepped leaders accompanied by regular trains of microsecond-scale pulses simultaneously seen by the broadband magnetic loop antenna SLAVIA (Shielded Loop Antenna with a Versatile Integrated Amplifier; 5 kHz-90 MHz), and the radio telescope LOFAR (Low Frequency Array; 30-80MHz). We investigate four pulse trains that occurred during complicated intracloud flashes on 18 June 2021, when heavy thunderstorms hit Netherlands.The pulses within the trains are unipolar, a few microseconds wide with an inter-pulse interval of about ten microseconds. The pulse trains last from 100 µs to 800 µs. After a careful time alignment of both magnetic field and LOFAR time series, we found that the broadband pulses perfectly match with regularly distributed and relatively isolated bursts of VHF sources localized by the LOFAR impulsive imager. All trains were generated by negative recoil stepped leaders propagating downward (two events) or upward (two events) at altitudes between 5.5 km and 8.5 km. Their tracks were formed by positive leaders occurring within the same flash several hundreds of milliseconds previously. The peak powers of VHF sources seen by the LOFAR electric antennas closest to the investigated discharges were about one order of magnitude higher than the power of signals emitted by normal negative leaders. These stepped recoil leaders propagate at a relatively low speed of about 2-5x10^6 m/s, when similar recoil leaders often reach speeds of 10^7 m/s. The velocity and inter-pulse intervals decrease towards the end of trains.We show that observed pulse trains are due to stepping recoil leaders. However, we consider this strong pulsing nature of the examined recoil leaders to be quite unusual. The physical mechanism giving rise to the energetic VHF bursts and accompanying regular microsecond-scale pulses remains unclear.
South Asian summer monsoon enhanced by the uplift of Iranian Plateau in Middle Miocene
Authors: Zuo Meng , Sun Yong , Zhao Yan , Ramstein Gilles , Ding Lin , Zhou Tianjun
Published: February 2023

The South Asian summer monsoon (SASM) remarkably strengthened during the Middle Miocene (16-11 Ma), coincident with the rapid uplifts of the Iranian Plateau (IP) and the Himalaya (HM). Although the development of the SASM has long been linked to the topographic changes in the Tibetan Plateau (TP) region, the effects of the HM and IP uplift are still vigorously debated, and the underlying mechanisms remain unclear. Based on Middle Miocene paleogeography, we employ the fully coupled earth system model CESM to perform a set of topographic sensitivity experiments with altered altitudes of the IP and the HM. Our simulations reproduce the strengthening of the SASM in northwestern India and over the Arabian Sea, largely attributing to the thermal effect of the IP uplift. The elevated IP insulates the warm and moist airs from the westerlies in the south of the IP and produces a low-level cyclonic circulation around the IP, which leads to the convergence of the warm and moist air in the northwestern India and triggers positive feedback between the moist convection and the large-scale monsoon circulation, further enhancing the monsoonal precipitation. Whereas the HM uplift produces orographic precipitation without favorable circulation adjustment for the SASM. We thus interpret the intensification of the Middle Miocene SASM in the western part of the South Asia as a response to the IP uplift while the subtle SASM change in eastern India reflects the effects of the HM uplift.
The carbon cost of mitigating air pollutant emissions from coal-fired power plants in China
Authors: Zhang Pengfei , Feng Kuishuang , Yan Li , Guo Yaqin , Gao Bei , Li1 Jiashuo
Published: February 2023

With the largest pollution-intensive coal-fired power plant (CFPP) fleet in the world, China has widely distributed air pollutant control devices (APCDs) to improve air quality. These APCDs are effective in mitigating air pollutants, at the same time, consume substantial carbon-intensive electricity from CFPPs. Nevertheless, the carbon cost of clean coal-fired power remains unexplored. Therefore, by collecting plant-level information, we quantified CO2 emissions induced by APCDs’ power consumption from China’s CFPPs. We show that from 2000 to 2020, CO2 emissions induced by APCDs in China’s CFPPs increased from 1.48 Mt to 51.7 Mt, and the ratio of power consumed by the APCDs to the total power generation increased from 0.12% to 1.19%. In 2020, the wet limestone-gypsum flue gas desulfurization device dominated the carbon emissions with a percentage of 80%, followed by the dust removal device’s 13% and denitration device’s 7%, respectively. Scenario analysis demonstrates that Inner Mongolia, Shanxi, and Shandong are the hotspots of APCD CO2 emissions in the future. The lifetime of CFPPs is an important factor affecting the scale of future APCD CO2 emissions. Our study underscores the urgency of a comprehensive assessment of environmental policies and urges the necessity of synergetic management of air pollutants and carbon emissions.
Towards more realistic modelling of tropospheric NO2 with WRF-Chem using fine-tuned temporal emission profiles
Authors: Kuhn Leon , Beirle Steffen , Kumar Vinod , Osipov Sergey , Pozzer Andrea , Bösch Tim , Kumar Rajesh , Wagner Thomas
Published: February 2023

NO2 is an important air pollutant and has been recognized for its hazardous impact on human health. Although routine in-situ measurements of NO2 are available in many regions of the earth, models for regional chemistry and transport (RCT) are often used to predict trace gas concentrations where no direct measurements are available. An important aspect of realistic NO2 modelling is to use accurate NOx emissions with high temporal resolution. The standard practice is to use a monthly or yearly resolved emission inventory in combination with sector-specific hourly emission weights (“temporal profiles”) in order to simulate diurnal, weekly, and seasonal emission patterns. Temporal profiles are typically derived from empirical data, e.g. car counts on highways, and have been known to improve RCT simulations significantly. Nonetheless, in comparison against in-situ measurements, simulated NO2 concentrations are usually too low at daytime and too high at nighttime, with relative deviations of up to 50 %. This hints towards faulty temporal emission profiles.We present a novel method to determine improved temporal emission profiles for NOx emissions in a WRF-Chem simulation for May 2019 in central Europe. The temporal profiles are determined in an iterative procedure that consists of running the simulation, comparing the simulated NOx concentrations to in-situ reference measurements, and adjusting the hourly temporal profiles to compensate deviations between simulation and reference values. In a subsequent intercomparison of model results with observational datasets (surface concentrations from in-situ measurements, tropospheric vertical column densities from the TROPOMI satellite instrument, and concentration profiles from MAX-DOAS retrievals), we validate our simulation results. In particular, the typical NO2 underestimation at noontime is resolved and the monthly average of simulated vertical column densities deviates less than 7% from the TROPOMI reference data.
Higher climate sensitivities weaken negative climate feedbacks of terrestrial ecosystem through carbon sequestration and nitrous oxide emissions
Authors: Gong Cheng , Caldararu Silvia , Engel Jan , Nabel Julia , Zaehle Sönke
Published: February 2023

Terrestrial ecosystem acts as important carbon dioxide (CO2) sinks and nitrous oxide (N2O) sources. Ecosystem green-house-gas fluxes could further lead to a climate feedback, which are highly correlated with the C-N coupling. However, magnitudes of such composited feedbacks as well as contributions by individual ecological processes remained certain uncertainties. Here, we applied a terrestrial biosphere model QUINCY with fully C-N-coupling to comprehensively examine responses of CO2 and N2O fluxes to future climate changes and quantify contributions by individual processes. Our results showed that the trade-offs in CO2 and N2O still led a negative feedback (-3386.9 Tg CO2 yr-1) averaged over 2050-2100 under the SSP 5-8.5 scenario relative to SSP 1-2.6 scenario, however, which varies from -1761.7 Tg CO2 yr-1 to -5012.1 CO2 yr-1 with a high or low climate sensitivity to CO2 increases.  Further process analysis showed that the CO2 fertilization effects on ecosystem climate feedbacks were equivalent for high and low climate sensitivity, but the higher climate sensitivity led to less carbon sequestration on tropical plants as well as higher N2O emissions. The climate feedbacks attributed to individual soil processes, including decomposition, nitrification, denitrification and nitrogen biological fixation, were also comprehensively quantified. This finding suggests that reducing the uncertainties in climate sensitivity estimates could be of great significance to better predict future terrestrial ecosystem green-house-gas fluxes as well as corresponding climate feedbacks.
Soil moisture and temperature dynamics in juvenile and mature forest as a result of tree growth, hydrometeorological forcings, and drought.
Authors: Rabbai Andrea , Wendt Doris E. , Curioni Giulio , Quick Susan E. , MacKenzie A. Robert , Hannah David M. , Kettridge Nicholas , Ullah Sami , Hart Kris M. , Krause Stefan
Published: February 2023

Afforestation, as one of the major drivers of land cover change, has the potential to provide a wide range of ecosystem services (ES). Aside from carbon sequestration, it can improve hydrological regulation by increasing soil water storage capacity and reducing surface water runoff.  However, afforested areas are rarely studied at the appropriate time scale to determine when changes in soil hydrological processes occur as the forest grows. This study investigates the seasonal soil moisture and temperature dynamics, as well as the event-based responses to precipitation events and dry periods between a mature and juvenile forest ecosystem over a 5-year time period. Generally, soil moisture was higher in the juvenile forest than in the mature forest, indicating less physiological water demand. However, following the 2018 drought, soil moisture dynamics in the growing juvenile plantation began to match those of the mature forest, owing to canopy development and possibly also to internal resilience mechanisms of the young forest to external perturbations. On the other hand, soil temperature dynamics in the juvenile plantation followed air temperature patterns closely, indicating lower thermal regulation capacity compared to the mature forest. While our findings reveal that an aggrading juvenile plantation achieves mature forest soil moisture dynamics at an early stage, well before maturity, this was not the case for soil temperature. Our results shed light on long-term trends of seasonal and event-based responses of soil moisture and temperatures in different-aged forest systems, which can be used to inform future assessments of hydrological and ecosystem responses to disturbances and forest management.
High time resolution PM 10 chemical composition of urban city influenced by industry and North-African dust outbreaks in SW Europe
Authors: de la Rosa Jesus , Sánchez de la Campa Ana M , Sánchez-Rodas Daniel A
Published: February 2023

In this work, we present the results of high time resolution PM10 chemical composition using online XRF spectrometer (Xact 625i) in the city of Huelva (SW of Spain) in September 2021-september 2022. The sampling was performed at the Campus monitoring station, which is belonging to Air Quality Network of the junta de Andalucía in the western part of the city of Huelva. Since 1970, Population is submitted to the hourly impact of industrial plumes related to Cu-metallurgy, phosphate production and petrochemical complex.A total of 30 elements were analyzed in an hourly resolution. Moreover, other on-line pollutants were analyzed (N, BC, SO2, NO2, O3 and PM10). To compare the results obtained by Xact 625i to conventional chemical procedures using ICP-MS, ICPOES, IC and TOT, daily chemical composition of PM10 was characterized every 4 days during one year of sampling.The results have shown how the impact of the industry occurs in the city of Huelva around 20% of the days every year. Days with poor air quality are influenced by the simultaneous impact of industry and North African air masses.Nucleation of PM is synchronous with elements related to industrial activity (SO2, As, Cu, Bi, Se, Pb, Ni, Zn and P). Another source of nucleation is traffic (BC, NO2, Sn and Sb ). The highest concentrations of mineral dust are related to north African outbreak air masses Two elements (Si +Al) may contribute more than the daily limit value for this pollutant (50 µg m-3).
Mapping moulins on the southwestern Greenland Ice Sheet
Authors: Wang Yuhan , Yang Kang , Liu Jinyu , Zhang Wensong , Man Mengtian , Chen Dinghua
Published: February 2023

Moulins are vertical meltwater pathways formed by hydro-fracturing of crevasses or supraglacial lakes. On the southwestern Greenland Ice Sheet (GrIS), moulins can efficiently drain surface meltwater into the ice sheet, drive subglacial drainage system development, control variations in subglacial water pressure, and eventually influence ice motion. Thereby, moulins are essential to understand the connection between supraglacial, englacial and subglacial drainage systems. However, most of existing studies focused on moulins in small areas or short time periods, leaving moulin spatiotemporal variations still unclear. In this study, we extracted moulins on the southwestern GrIS from 2016 to 2021 using multi-temporal Sentinel-2 satellite images and ArcticDEM, and analyzed their interannual spatiotemporal variations. Results show that: (1) Moulin distribution varies significantly in different years. In general, moulin numbers increase linearly with the rise of accumulative annual meltwater runoff, while the terminal supraglacial lake numbers decreased exponentially. (2) The annual moulin distribution can affect the distributions in subsequent years, and the smaller the intervals, the stronger the effect. (3) There are significant variations in the meltwater runoff draining into the ice sheet in different years, especially in high elevation region (>1600 m).
Effect of thermal damage on capturing fracture signal of high temperature sandstone subjected to cooling shock from the coal fire control project
Authors: Ge Shaokun , Shi Bobo , Zhang Shuai , Deng Jinchang , Wu Chunlei
Published: February 2023

In the coal fire control project, the multiple water injections used to extinguish coal fires and the coal fires that reignite can cause many forms of ground collapse to occur, threatening project safety. Therefore, studying the thermal damage and capturing disaster signals of sandstone, a main weight bearer in coal measure strata, exposed to heating-cooling, cycles is critical to ensure the engineering safety. In this work, the coal-measure sandstones from Urumqi, Xinjiang and Yulin, Shaanxi, China, were collected. For the sandstones from Urumqi, China (Type A sandstone), the samples were first heated to 800 °C, and cooled using water, heated to a setting temperature (100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C and 800 °C), and cooled using water again. The ultrasonic p-wave velocity, density and water absorption of the sandstones were tested. Uniaxial compression tests and shear tests were conducted on the sandstones. The thermal damage in sandstones were analysed using rock energy theory. For the sandstones from Yulin, China (Type B sandstone), the X-ray diffraction test, scanning electron microscope test and uniaxial compression experiment with AE monitoring were carried out for the raw sandstone and the sandstone exposed to 800 °C and water cooling twice (cooling shock sandstone), respectively. The results show that, for the type A sandstone, compared with the mechanical strength of the sandstone at room temperature, the mechanical strength of the sandstone exposed to 800 °C for the first time is decreased by less than 20%. When the sandstone is exposed to high temperature again, the critical threshold temperature is 400 °C. When the temperature exceeds 400 °C, the thermal damage aggravated again and the mechanical strength rapidly degraded. For the type B sandstone, the results showed that the crack density and volume of cooling shock sandstone increased by 8.79% and 2.69%, respectively, and p-wave velocity decreased by 51.83%, compared with those of the raw sandstone. The mechanical strength of cooling shock sandstone decreased, including a 50.68% reduction in elastic modulus. The AE attenuation coefficient α=(1-Ec/E0) /kc, related to the elastic modulus and the crack change rate, was derived, which providing an approach to count the attenuation of AE signal caused by thermal damage for cooling shock sandstone. Increasing the preamplifier amplification factor is feasible to improve the accuracy for monitoring the fracture of cooling shock sandstone in coal-fire control project.
Is the North Atlantic modulating wintertime influence of NAO on Europe temperatures?
Authors: Piskozub Jacek
Published: February 2023

Winter (December-March) temperatures in most Europe is strongly correlated with the zonal circulation index of the Atlantic sector, North Atlantic Oscillation (NAO), regardless of which from its several available definitions to choose. However, the variability of this index also has a distinct multi-decade component, which makes it difficult to study trends of several decades. In addition, the NAO index itself is also significantly positively correlated with the global anthropogenic forcing and with the global temperature itself. Therefore, using purely statistical methods, it is not easy to distinguish the influence of zonal circulation variability from the trend resulting from the increasing forcing of greenhouse gases when examining the variability of winter temperatures in Europe.Because of the prevailing western circulation, wintertime temperature in Europe should dpend on the intensity of the western circulation (NAO) as well as the sea surface temperature (SST) of the ocean (indexed by AMO – Atlantic Multidecadal Oscillation). However winter is the only season when there is no statistically significant correlation of AMO and temperatures in Europe. This surprising result had no explanation until the recent discovery of the northern shift of synoptic systems correlated with AMO. This could offer a “Bjerknes compensation” type of effect where the ocean circulation modifies the atmospheric one, making the air masses arriving in winter to Europe sourced in areas of the same SST, regardless of AMO (or general warming of the North Atlantic).This study uses the data on SST and pressure fields as well as the NAO and AMO, together with an index if temperatures of Poland (as a proxy of Central Europe) in order to throw light on the relationship. The results confirm the existence of a “Bjerknes compensation” mechanism as well as suggest a dependence of wintertime NAO on the greenhouse forcing (visible in their significant correlation), caused most probably by the recently discovered strengthening of wintertime jet stream over the North Atlantic. This relationship can have important impact on future winter temperatures in a large part of Europe and therefore its possible mechanisms should be the point of further research. This work been performed as a part of the SURETY project , funded by Polish National Science Centre (NCN), contract 2021/41/B/ST10/00946. 
ModE-RA - the Modern Era Reanalysis
Authors: Franke Jörg , Veronika Valler , Hand Ralf , Samakinwa Eric , Burgdorf Angela-Maria , Lundstad Elin , Brugnara Yuri , Hövel Laura , Brönnimann Stefan
Published: February 2023

The Modern Era Reanalysis (ModE-RA) extends current re-analysis back until the year 1420 CE at monthly resolution. It combines our understanding of physics coming from an ensemble of atmospheric model simulations with all available direct and indirect climate observations of monthly to annual resolution. A 20-member ensemble of atmospheric model simulations (ModE-Sim) driven by an ensemble of external forcings and an ensemble of new sea surface temperature reconstructions serves as a prior estimate of the possible climate states at each assimilation time step. After the entire simulations were completed, we assimilated multiple data sources using an offline Kalman filtering technique. We include up to ~100000 monthly to annual observations per year. These consist of thousands of existing and newly digitised instrumental measurements of temperature, precipitation, wet days per months, and pressure, including measurements made on ships over the ocean and in harbours. Earliest instrumental station data go back to the year 1658. Additionally, we collected and digitised climate information from historical documents, including phenological data. These are especially valuable for the autumn, winter and spring season and go back to the year 1420. Finally, we assimilate annually resolved climate proxies. The vast majority are tree-ring observations, which represent growing season conditions on the continents. In otherwise data sparse regions, we supplemented ice and coral data at high latitudes and the tropical oceans, respectively. ModE-RA offers especially  insides into interannual to multidecadal variability such as phases of accelerated warming, monsoon strength or subtropical droughts as well as rare events such as volcanic eruptions. 
IRiS: a professional telescope at the service of students
Authors: Jammart Emmanuelle , Basa Stéphane , Mille Bertille , Lemee Lisa , Marchand Lou-Eva , Marciaux Clément , Chiev Emily , Houari Mazir
Published: February 2023

Sup’sciences is a group of around ten students of 11th and 12th level, chosen among volunteers in the Lycée Branly (Dreux, France). We talk about scientific projects and scientific research. This year we study the space with IRiS. We also went to the National Museum of Natural History and we invited the scientist we met there for a conference. It can help for our orientation because we deal with the scientific approach and we can see different jobs related to science.IRiS (French acronym for Initiation to Astronomical Research for Students) is a semi-professional telescope built for students to perform astronomical observations. It is located in the Haute-Provence Observatory (OHP), near Saint-Michel-l'Observatoire in the Southern French Alps. The telescope is controlled at distance using a web page, which is very simple to use (a simple one-hour training for the teacher in charge of the class is sufficient). The individual pictures are taken using filters (near-infrared to ultraviolet).We applied for a first project in scholar year 2021-2022. The idea was to make a celestial trip and discover nice objects in the deep sky. First of all, the students were invited to visit the historical astronomical observatory in Paris downtown, to discover ancient instruments and discuss with a famous astrophysicist, Françoise Combes. On January 3rd, 2022, we made our first observation night. The telescope first was focused on the Orion constellation and, by trials and errors, we succeeded to make great images, particularly the Horsehead Nebula. We met a second time, on February 2nd, 2022, but the wind cancelled the observation night before all observations. The students took advantage of this evening to analyze and combine the first session images, in order to make colored compositions.For the scholar year 2022-2023, a new project was accepted by the IRiS team. We would like to focus now on planets. As IRiS allows only imaging deep sky objects, we will use it to observe exoplanets transits in front of their star by measuring its transitory luminosity diminution. Unfortunately, the telescope’s camera broke down just before our night and we have to wait. Meanwhile, we got in touch with a local astronomy association. Our first observation night, allotted to Moon and Solar System planets observation, was cancelled because of the bad weather, but another night is planned in January.
Zonally Asymmetric Response of Southern Ocean Heat Content to Wind, Heat and Freshwater Forcing at Multi-decadal Time Scales
Authors: Hague Mark , Gruber Nicolas , Münnich Matthias
Published: February 2023

Since it was recognised that the Southern Ocean plays a crucial role in global climate, the region has generally been understood in a zonally symmetric framework. While this simplification has provided valuable insight, recent work suggests that significant zonal asymmetries exist in several key parameters such as SST, mixed layer depth and air-sea CO2 flux. This is true both for the mean state and for changes at multiple time scales. Of particular interest here are changes in ocean heat content (ΔOHC) over the past three decades. Using an eddy-permitting ocean model forced by ERA5 reanalysis, we find significant asymmetries in ΔOHC both within and north of the ACC, which is robustly reflected in a suite of hindcast and reanalysis models, as well as observation based temperature reconstructions. In our model, asymmetry stems largely from a southward displacement of ΔOHC in the Indian basin, where warming occurs primarily within ACC, as opposed to north of it in the Atlantic and Pacific. However, significant asymmetries are also found within the sea ice zone south of 60o S, where the Ross Sea warms to a much greater degree than other basins. In order to better understand the sources of this asymmetric warming, we run several model experiments which decompose the total OHC into components originating from wind, heat and freshwater flux changes. We find roughly equal contributions from wind and surface heat flux north of the ACC, with asymmetric changes in the westerlies driving anomalous convergence of heat. Within and south of the ACC all three forcings play an important role, although this depends strongly on the basin. Overall, we conclude that much of the asymmetries in ΔOHC originate from asymmetries in the surface flux changes, with an important secondary role played by variability in the mean state. These findings have two important implications. First, studies which only consider zonally averaged quantities will likely mask significant variability, and therefore miss important regional and local processes. Second, the impact of multi-decadal climate variability on the Southern Ocean is not manifested in a zonally symmetric fashion, which may have important implications for future changes. 
The spatio-temporal dynamics of the relationship between gross primary productivity and solar induced chlorophyll fluorescence across the agricultural ecosystem of India
Authors: Behera Subhrasita , Dutta Debsunder
Published: February 2023

Food security is dependent on agriculture as such prediction and monitoring of crop yield is of essential importance. Crop productivity primarily depends upon its potential to transmute light energy to sugar through photosynthesis and the total amount of carbon fixed by this process is coined as Gross Primary Production (GPP). Therefore, a reliable estimation of GPP is a vital step toward crop monitoring. Typically, accurate quantification of GPP at various spatial and temporal scales through the light use efficiency models remains challenging. Novel remote sensing methods such as Solar Induced chlorophyll Fluorescence (SIF) is a direct probe into the photosynthetic machinery and has been demonstrated to be a much better indicator of primary production compared to traditional vegetation indices. SIF has also been demonstrated to be a proxy for GPP as well as estimating crop productivity. However, most studies focus on homogeneous crop areas across the globe by using satellite or ground-based SIF concurrently with flux tower GPP. In this study, we examine how well satellite-based SIF products can monitor the GPP and crop productivity across the heterogeneous cropping system of India. Linear correlation analysis is carried out to analyse the relationship between FLUXCOM GPP with Global Ozone Monitoring Experiment-2 (GOME-2) SIF and TROPOspheric Monitoring Instrument (TROPOMI) SIF at different spatio-temporal scales. The results indicate a significant pixel-wise correlation at 8 daily and monthly scales across the crop area of India. However, a weak linear correlation is found between GPP and SIF at yearly scale. From the analysis of TROPOMI SIF and GOME-2 SIF, we find that TROPOMI SIF has a higher potential to predict GPP across the crop area of India. To explore the spatial and temporal variability in GPP and SIF relationship, we used GPP/SIF ratio as an indicative parameter. The maximum GPP/SIF values occurred in September and October. We found the seasonal pattern of GPP/SIF ratio following the seasonal dynamics of Leaf area index (LAI, canopy structural metric). During peak growing season GPP/SIF was positively corelated to short wave radiation and moisture availability, but during the early growing season it mostly dependent on soil moisture. Our results will enhance the understanding of the mechanisms of the link between GPP and SIF. 
Walking around the geopark of Cabo de Gata-Níjar- Spain
Authors: Cantos José Miguel
Published: February 2023

Walking around your place and doing some field work is essential to know and learn in Geoscience, especially considering that my students and I live next to the Cabo de Gata-Níjar Geopark. The teachers of the biology and geology department plan outdoor activities within the curriculum for our students every year:- All first level students in high school are invited to visit the botanical garden and the volcanoes house in Rodalquilar, both located in the heart of our Geopark.- All third level students must go walking to the beach “El Algarrobico” to research about the coast, with previous stops in some geological and botanical spots.- All fourth level students can visit the gypsum caves in the karst of Sorbas, a unique protected natural land close to big quarries.- Our older students in first level of bachellor go for walks outside our school with the collaboration of physical education teacher. Besides they are invited to participate in the local phase of geology olympiads, at the University of Almería for a weekend.
Macroscopic root water uptake modelling using High-Throughput Screening (HTS) systems: Design and Validation
Authors: Puig Sirera Angela , Bonzi Lorenzo , Hamouda Fatma , Sbrana Andrea , Remorini Damiano , Cotrozzi Lorenzo , Rallo Giovanni
Published: February 2023

Climate change and intensive agriculture are responsible for the increasing frequency and intensity of abiotic stresses generating conditions of water scarcity. Currently, there is the need to select and release, in a short time, plants adaptable to the current and future environmental conditions and resistant to biotic and/or abiotic stress. This study presents the design and validation of a High-Throughput Screening (HTS) system for the continuous and simultaneous monitoring of the plant stress response to drought in a semi-controlled environment.Structurally, the HTS-system is formed by three hardware segments to detect with high-frequency the agrometeorological variables (i.e., atmometry), the weights (i.e., gravimetry), and the soil water content (SWC) (i.e., time domain reflectometry, TDR) of sixteen pots in which the medicinal crop Salvia officinalis L (sage) was grown. Two irrigation treatments, one based on full irrigation and the second on soil water deficit conditions, were applied following a feedback control irrigation scheduling protocol, and an automated micro-irrigation system was designed to manage them.The system was able to model the sage water stress function following the root water uptake (RWU) macroscopic approach. The threshold of soil water status below which crop water stress occurred was also identified. The gravimetric-based daily evapotranspiration (ETc act) and the time domain reflectometry (TDR) -based RWU rates showed a high correlation, which allowed validating the RWU indicators based on soil moisture sensors to estimate the ETc act fluxes.Keywords. Agro-hydrological modelling, high-throughput systems; root water uptake; sage; water stress function
Seismic signature of carbonate fault rocks changes with changing petrophysical properties: insights from unmigrated seismic forward modelling
Authors: Tomassi Andrea , Trippetta Fabio , de Franco Roberto
Published: February 2023

The most common method of detecting subsurface structures on continental and marine surfaces is seismic imaging. Although technological advancements have been made, seismic analysis of carbonates remains challenging due to their strong petrophysical heterogeneity, which becomes more challenging when faults are incorporated. This work aims to produce unmigrated forward-seismic models to grasp the deformation behavior of carbonate-bearing fault systems and the related seismic response changes. The porous and faulted carbonates outcropping at the Majella Massif (central Italy) are here used as case study as an analogue of carbonate ramp reservoirs exploited worldwide. Field and laboratory petrophysical data of fault rocks collected at increasing distances from the fault planes show a damage zone/fault core architecture characterized by a decreasing porosity and an increase in shear modulus moving from host rocks towards fault planes. Starting from these observations, unmigrated stacked seismic models have been built simulating fault zones with both increased and decreased porosities with respect to the host rocks. Fault zones with lower porosity than the host rock show slight diffraction hyperbolas, while the diffractive component is pronounced in seismic images of fault rocks with higher porosity than the host rock. Such hyperbolas can be enhanced or weakened by modifying the dip angle of the fault plane or the width of the damage zone but a key role seems to be played by the decreased porosity. The existence of diffraction hyperbolas in unmigrated seismic models is then interpreted as evidence of a damage zone characterized by larger porosity compared to the host rock. Migrated stacked sections would not provide any evidence of increased porosity in the damage zone due to loss of information about the diffractive component resulting from the processing. Consequently, the absence of diffraction hyperbolas in actual unmigrated seismic images is suggested to be related to a decreased porosity in the fault zone. This can be related to cataclasis and solution/cementation of the damage zone rocks as observed in the study area, and related to confining stress acting at depth or fracture filling that counteracts the fracture-related increase in secondary porosity. On the other hand, diffraction hyperbolas in unmigrated seismic images can represent a clue of the presence of large-porosity fault zones.
Gravitational curvatures for a tesseroid and spherical shell with arbitrary order polynomial density
Authors: Deng Xiao-Le
Published: February 2023

In recent years, high-order gravitational potential gradients and variable density models are the potential research topics in gravity field modeling. This paper focuses on the variable density model for gravitational curvatures (or gravity curvatures, third-order derivatives of gravitational potential) of a tesseroid and spherical shell in the spatial domain of gravity field modeling. In this contribution, the general formula of the gravitational curvatures of a tesseroid with arbitrary order polynomial density is derived. The general expressions for gravitational effects up to the gravitational curvatures of a spherical shell with arbitrary order polynomial density are derived when the computation point is located above, inside, and below the spherical shell. The influence of the computation point's height and latitude on gravitational curvatures with the polynomial density up to fourth order is numerically investigated using tesseroids to discretize a spherical shell. Numerical results reveal that the near-zone problem exists for the fourth-order polynomial density of the gravitational curvatures, i.e., relative errors in log10 scale of gravitational curvatures are large than 0 below the height of about 50 km by a grid size of 15'x15'. The polar-singularity problem does not occur for the gravitational curvatures with polynomial density up to fourth order because of the Cartesian integral kernels of the tesseroid. The density variation can be revealed in the absolute errors as the superposition effects of Laplace parameters of gravitational curvatures other than the relative errors. The derived expressions are examples of the high-order gravitational potential gradients of the mass body with variable density in the spatial domain, which will provide the theoretical basis for future applications of gravity field modeling in geodesy and geophysics. This study is supported by the Alexander von Humboldt Foundation in Germany. 
Sand flux in a desert site of Mongolia
Authors: Munkhtsetseg Erdenebayar , Shinoda Masato , Gillies John , Shao Yaping
Published: February 2023

Mongolia experiences frequent dust and sand storms, particularly in the spring. As a result, this country losses a huge amount of top soils, which triggers land degradation and desertification. We measured sand flux of 2 consecutive dust storm cases occured in 2011 using BSNE (Big Spring Number Eight) sand traps installed at the Bulgan meteorological station in the Gobi area .Vertical gradients for the sand mass (flux) demonstrated 3 typical patterns:a) sand flux increases with height when there is a transported sand from the areas distanced away from the study site
b) sand flux is constant vertically in the days following dust sand storm (DSS)
c) sand flux declines exponentially with the height when DSS occur at the site.
Among these three typical patterns, we investigated the c) pattern to quantify the amount of eroded soil during the on-site dust emissions of dust storm event (DSS) at the site. The DSS was largely associated with the increased friction velocity excluding some cases those are related to a short time-span of rainfall even though underlain by dry soil surface etc. Furthermore, we estimated a saltation height, Zq, which was much greater (30 cm) than the other reported findings (3-10 cm).Keywords: sand flux patterns, saltation height, sand traps, Mongolia
Analysis of the Feasibility of a low-cost DAQ for EM-38Detection and Mapping
Authors: Hamouda Fatma , Bonzi Lorenzo , Provenzano Giuseppe , Puig-Sirera Àngela , Sbrana Andrea , Remorini Damiano , Rallo Giovanni
Published: February 2023

Abstract. The EM-38 is a Handheld Electrical Magnetic Induction (EMI) device, non-invasive and commonly used for monitoring salinity, mapping bulk soil properties, and evaluating soil nutrient status. The measured data is an electrical conductivity, [mS/m], which was referred to a representative soil volume of 1.0-1.5 m depth and 2.0 m width.The Data AcQuisition (DAQ) system for EM-38 (Geonics Inc.) conductivity meter, used for recording the spatial variability of the soil bulk electrical conductivity (EC), is expensive, according to the proprietary software, and do not provide detailed, modifiable circuit schematics.To address these issues, we developed an easy-to-use, modifiable, and inexpensive data acquisition (DAQ) system for EC data recording and spatializing. In particular, this work investigates the feasibility of using a low-cost open-source DAQ system to be installed on an EM-38 conductivity meter (Geonics Inc.). This DAQ system is based on Raspberry Pi and allows collecting speed and position of the EM-38 device by carrying it on a specific designed sled system.The EM-38 data (± 200mV) were acquired by A/D converter 24 bit and GPS data ($GPGGA, $GPRMC [NMEA 0183]) were obtained by serial input RS232. The Data logger (Raspberry Pi 4) stored the acquired data and transferred it to the server using an internet connection (Router 4G). The control Firmware has been written in Python language. To ensure the accuracy and reliability of the collected data, the system has been evaluated and tested in well-known open-filed (CIRAAA-a reserch center of the University of Pisa), where the spatial variability of the main soil physical properties (i.e. soil texture, organic matter, electrical conductivity) are known.The performance has been evaluated by comparing the data string with the one generated by a professional DAQ system. The latter includes a CR1000 data logger (Campbell Scientific) to control and store the EC data and integrats a GPS receiver (GPS16X-HVS, Garmin Inc.) which provides the position, velocity, and timing information.First results allowed to approve the possibility to extract the analogical signal from the device, which is strongly responsive to the variation of the physical properties of the soil environment. Moreover, the device is able to estimate accurately the spatial patterns of the investigated soil physical properties. Keywords: Precision farming, Zoning, EMI sensors, soil bulk electrical conductivity, open source DAQ
Jupiter’s 3.3-micron CH4 polar brightening: Retrieval of methane effective temperature in the jovian auroral regions using Juno/JIRAM data
Authors: Castagnoli Chiara , Dinelli Bianca Maria , Altieri Francesca , Migliorini Alessandra , Mura Alessandro , Adriani Alberto , Sordini Roberto , Tosi Federico , Noschese Raffaella , Piccioni Giuseppe , Moriconi Maria Luisa , Grassi Davide , Cicchetti Andrea , Moirano Alessandro , Filacchione Gianrico , Sidoni Giuseppe , Plainaki Christina , Scarica Pietro , Turrini Diego
Published: February 2023

Despite the multiple evidence of the diffuse presence of methane in Jupiter’s auroral regions, the mechanisms leading to the CH4 brightening observed both from ground- and space-based platforms are not yet fully understood. During the first NASA/Juno’s orbit, the on-board imager/spectrometer JIRAM (Jovian Infrared Auroral Mapper) detected the 3.3-µm methane emission on both Jupiter’s poles. The signal was found to be mostly confined within the main auroral ovals, although the lack of spectral coverage over 80°S prevented a deep investigation of the southern methane spot. The CH4 polar emissions at 3.3 µm are likely originated by non-thermal excitation mechanisms occurring above the 1 µbar level, such as auroral particle precipitation and/or Joule heating. However, aurorally driven upwelling of methane inside the main oval might also explain the enhanced concentrations of CH4 observed at the jovian poles. To address this controversy, we derive the effective temperature of methane in Jupiter’s auroral regions, which is a key information to understand the origin of the detected fluorescence. The goal is achieved by exploring three Juno’s orbits and focusing on the spectra with the highest methane emissions and the smallest contribution from other auroral features due to H3+. JIRAM measurements from the first perijove are used to investigate the northern methane brightening, while observations from perijoves 7 and 8 are examined for its southern counterpart. The analysis reveals similar temperatures in the north- and south-polar spots, mainly ranging between 400 K and 670 K.  