bluuebunny/crossref_metadata_2025 huggingface dataset:
Coastal dynamics in middle-south Vietnam during a transition period of Asian monsoon, characterized by HF radar measurements and numerical modeling
Authors: Tran Thanh Huyen , To Duy Thai , Sentchev Alexei
Published: February 2023

The middle southern coasts of Vietnam (11-15ºN) are featured by a large upwelling in summer which is governed by various physical processes i.e. regional circulations, monsoonal wind, and tidal rectification. Through the HF radar measurements acquired during April-May, 2019, a transition period of the Asian monsoon, three prominent patterns of local circulation have been revealed: a northern current intrusion as a result of South China Sea Western Boundary Currents (SCSWBC); a strong southeast jet occurring at ~30km from the coast; and a seaward current appearing for several days. In order to acquire a better understanding of the regional hydrodynamics, a 3D circulation model SYMPHONIE was run covering the measurement periods of HF radar and AWAC. Sea surface current (SSC) time series obtained from HF radar and AWAC were found to be strongly correlated (R=0.58, RMSE=0.10, MAE=0.07 for u- and R=0.72, RMSE=0.13, MAE=0.11 for v-components) (Fig 1). Three subdomains (nearshore, middle-range and far-range) have been identified within the radar coverage region for detailed analysis and comparison with the model. The comparison revealed that during the first 20 days, when the SE wind prevailed, the model does not seem to capture well the variability of SSC (Fig 2). However, when the wind changed to S-SW direction, the model results show a good agreement with HF radar measurements. Besides, an eddy forming near the coast on April 16 has been well represented by both model and HF radar (Fig 3). The uncertainty of modeled velocity fields can result from the uncertainty in forcing fields. Thus, the next step of our research will be to optimize the forcing field (i.e., wind) using HF radar data with an expectation to achieve better model results of SSC variability. Figure 1 Comparison of SSC time series from  HF radar (black solid line) and AWAC (red asterisk points)Figure 2 Space averaged U- and V-velocity components of SSC from SYMPHONIE model (dash line) and HF radar measurements (solid line) in three subdomains: nearshore (a, d); middle range (b, e) ; and far range (c, f). Wind vector during the measurement period (g).Figure 3 An eddy in SYMPHONIE model simulation (left)  and HF radar measurements (right) on  April 16, 2019. Color scale represents curl of surface velocity superimposed by SSC vectors. Isobaths are shown by black lines.
Study on the effective disaster risk management and communication for resilient community
Authors: Chuang Mo-Hsiung , Ma Kuo-Chen , Tan Yih-Chi
Published: February 2023

This 27th United Nations Climate Change Conference clearly pointed out that global warming is progressing. The threat of climate change and extreme disasters will increase rapidly, and the risk of community disasters will increase significantly. Therefore, effective disaster risk management and risk communication can enable community residents in disaster potential areas to understand disaster risks and build disaster prevention organizations, which has become a Practitioner in Disaster Risk Management. This study aims to explore training methods for resilient Communities. These include community environment diagnosis map making, including natural disaster risk and vulnerability discussion and disaster prevention map drawing, and secondly, how to train resilient community to conduct disaster risk control and disaster management measures before or during disaster events and recovery periods. Finally, combine the geographic information of the public sector and volunteers to conduct public-private cooperation to build disaster risk management and practice with resilient communities as the key players.
Root shrinkage and its mechanisms: why context matter
Authors: Di Bert Sara , Carminati Andrea , Duddek Patrick , Benard Pascal , Papadopoulou Konstantina
Published: February 2023

Modeling plant responses to drought over short-to long-term is crucial under rising global warming threats. Roots form the critical gateway between a plant and its water sources in the soil, yet their connection with the soil is still poorly understood. As the soil dries, roots shrink gradually disconnecting from the surrounding soil. This progressive reduction of root-soil contact interrupts the liquid-phase continuity and limits the water movement. The importance of the loss of contact between soil and roots depends on the water potential at which this occurs. If roots lose contact at potential close or beyond the wilting point, when the low soil hydraulic conductivity is already limiting, the loss of contact might not be as important. But if this occurs in still relatively wet conditions, it might trigger an earlier limitation of root water uptake.Currently, it is known at what water potential roots lose contact with the soil. Furthermore, we expect that this critical water potential is not unique, but it depends on soil properties, soil particle size and porosity, and root properties, such as root hair density and mucilage production.Here we present an analysis to identify and quantify the forces that bind the soil to the root for different soil textures. We estimate the adhesive forces that hold roots in contact with the soil and that counteract root shrinkage caused by decreasing water potential and cells losing turgor. The ingredients of our analysis are: root hairs, capillary forces and mucilage elastic properties. Thresholds of gap formation at the root-soil interface are identified for varying soil particle size and porosity and for varying root hair density and mucilage elastic properties.This analysis shows that root-soil contact dynamics do not depend only on the root cell turgor loss point, but also on soil properties, and helps to identify the mechanisms impacting the hydraulic continuity across the root-soil interface.
Microseismic triggering by small sinusoidal stress perturbations at the laboratory scale
Authors: Colledge Martin , Aubry Jérôme , Chanard Kristel , Pétrélis François , Duverger Clara , Bollinger Laurent , Schubnel Alexandre
Published: February 2023

Small transient stress perturbations are prone to trigger (micro)seismicity. In the Earth's crust, these stress perturbations can be caused by various sources such as the passage of seismic waves, tidal forcing, or hydrological seasonal loads. A better understanding of the dynamic of earthquake triggering by transient stress perturbations is essential to improve our understanding of earthquake physics and our consideration of seismic hazard.Here, we study an experimental sandstone-gouge-filled fault system that undergoes creep with combined far field loading and periodic stress perturbations at crustal pressure conditions. This complex loading is analogous to the loading experienced by faults in the natural setting.Microseismicity — in the form of acoustic emissions (AE) — strains, and stresses, are continuously recorded to study the response of the system as a function of loading rate, amplitude, and frequency of a periodic stress perturbation. The observed temporal distributions of the AEs disagree with the theoretical results of a Coulomb failure model considering both constant loading and oscillation-induced strain rates. This implies that the stress perturbations are of shorter period than the nucleation time of the AEs of the system. A susceptibility of the system’s AE response to confinement pressure amplitude is estimated, which highlights a linear relation between confinement pressure amplitude and the AE response amplitude, observations which are consistent with recent higher frequency experimental results on dynamic triggering.The magnitude-frequency distribution of AEs is also computed. The Gutenberg-Richter b-value oscillates with the stress perturbations, the amplitude of the b-value oscillations increasing with the amplitude of the stress perturbations, as observed in natural catalogues with large stress oscillations. Our experiments may complement our understanding of the influence of low inertia stress phenomena on the distribution of seismicity, such as observations of dynamic triggering and seismicity modulation by solid earth tides or seasonal loading.
Observationally constrained analysis of sulfur species in the marine troposphere
Authors: Bian Huisheng , Chin Mian , Colarco Peter , Liu Mingxu , Tronstad Lund Marianne , Matshi Hitoshi , Penner Joyce , Wang Hailong , Zhang Kai , Zhu Jialei
Published: February 2023

The NASA Earth Venture Suborbital (EVS-2) Atmospheric Tomography Mission (ATom) provided rich gas and aerosol measurements over the global oceans. In this study, we investigate the sulfur species of dimethyl sulfide (DMS), sulfur dioxide (SO2), methane sulfonic acid (MSA), and sulfate (SO4) that were measured during the ATom aircraft campaigns and simulated by five AeroCom models. This study focuses on remote regions over the Pacific, Atlantic, and Southern Oceans from near the surface to ~12 km altitude and covers all four seasons. We examine the vertical and seasonal variations of these sulfur species over tropical, mid-, and high latitude regions in both hemispheres. We identify their origins from land versus ocean and from anthropogenic versus natural sources with sensitivity studies by applying tagged tracers linking to emission types and regions. Using the GEOS model, we also investigate impact of cloud simulation (i.e., one-moment bulk cloud module, 1MOM vs two-moment cloud microphysics module, 2MOM) on the sulfur cycle and identify critical mechanisms of cloud impact by performing process-level budget analyses. Generally, SO4 has a better model-observation agreement than DMS, SO2 and MSA, and there are much larger DMS simulated concentrations close to the sea surface than measured, indicating all model DMS emissions may be too high. Anthropogenic emissions are the dominant source (44-60% of the total amount) for atmospheric SO4 simulated along ATom flight tracks in almost every altitude, followed by volcanic eruptions (18-33%) and oceanic sources (16-28%). GEOS SO4 simulations differ significantly between the 1MOM and 2MOM cloud schemes, with the sulfate chemical production via aqueous phase reactions seeming to be the critical process.
Assessing the impact of climate change and anthropogenic factors on future salinization of a low-lying coastal groundwater system (Northwestern Germany)
Authors: Seibert Stephan L. , Greskowiak Janek , Karrasch Leena , Siebenhüner Bernd , Oude Essink Gualbert H.P. , van Engelen Joeri , Massmann Gudrun
Published: February 2023

Coastal fresh groundwater reservoirs are often threatened by different salinization processes. Anthropogenic drivers for salinization include groundwater abstraction, land cultivation and artificial drainage. Global climate change, which modifies groundwater recharge patterns and results in sea-level rise, presents another important process enhancing groundwater salinization.A good understanding regarding the physical behaviour of coastal groundwater systems is needed for sustainable management, including the development of effective counter measures to antagonize future groundwater salinization. At present, however, such knowledge is incomplete.The aim of this study was to clarify the role of important factors expected to affect future groundwater salinization of low-lying coastal groundwater systems, namely sea-level rise, varying groundwater recharge and abstraction rates, changing drainage and river levels as well as land subsidence. A novel numerical 3-D variable-density groundwater flow and salt transport modeling approach was developed for this purpose, using Northwestern Germany as case study. To systematically evaluate the role of the individual salinization factors, separate model variants were employed.We found that sea-level rise causes strongest salinization, particularly close to the coastline. Lifting of drainage levels results in freshening of the marsh areas, while a decrease of drainage levels amplifies salinization. Variation of groundwater recharge patterns and abstraction rates have least impact on regional groundwater salinization. As the system is not at steady-state, autonomous salinization will continue into the future and contribute a significant portion of salt loads until the end of the 21st century. Findings and implications of this study may be relevant to similar low-lying coastal groundwater systems around the world.
Unravelling the origin of the atmospheric moisture deficit that leads to droughts
Authors: Gimeno-Sotelo Luis , Sorí Rogert , Vázquez Marta , Nieto Raquel , Vicente-Serrano Sergio M. , Gimeno Luis
Published: February 2023

Drought is the main natural hazard at the planetary scale and although this is a very complex phenomenon that involves many aspects of the hydrological cycle, there is always a deficit of precipitation compared to usual, understanding usual as climatological. This deficit can occur essentially for three reasons, either because there is less moisture available in the air column or because there is less atmospheric instability that forces air to rise, or for both reasons simultaneously. As the existing local humidity in the air column is mostly insufficient to justify precipitation, less humidity available for precipitation implies a deficit in the moisture which reaches the site in question. Therefore, on a global scale, moisture transport deficits lead to the occurrence of droughts.In a first approximation, this humidity can have two origins, or comes directly from the ocean, or is subsequently recycled from the continents themselves. The processes that control the evaporation over oceans or the continents as well as the moisture transport are very different, and there is a variable relationship between the oceanic and terrestrial origin of precipitation both globally and regionally. In a second approximation, the main sources of humidity at a global level are those regions where evaporation greatly exceeds precipitation over them, which mainly occurs in the subtropical oceans, some inland seas, and the two continental areas known as green oceans, the Amazon and the Congo basins.It is known where the humidity coming from the whole ocean or the whole continent precipitates, as well as the sinks of the humidity that comes from these large individual sources. It has also been studied how anomalous moisture transport affects droughts in specific regions, but the probability of occurrence of droughts at a planetary scale on continental areas given a deficit of the moisture transported from the global oceanic area, the global continental area, and each of these major sources has not been fully evaluated. Here we make use of a Lagrangian approach widely used and checked, which consists of estimating how much precipitation comes from the humidity arriving from a specific moisture source and enables to reveal the origin of the atmospheric moisture deficit underlying the occurrence of droughts. 
How to overcome different limitations in estimating plant diversity via spectral diversity?
Authors: Rossi Christian , Hauser Leon , Gholizadeh Hamed
Published: February 2023

Technological advances in optical remote sensing, which measures the electromagnetic radiation reflected by an object at various wavelengths, allow for efficient and relatively inexpensive collection of baseline data related to biodiversity. In particular, spectral diversity—the variability in remotely sensed spectral reflectance data obtained from plant communities—has emerged as a valuable proxy for different facets of biodiversity, such as plant taxonomic, phylogenetic and functional diversity. However, successful estimation of plant diversity using spectral diversity is negatively impacted by several factors, including: i) limited or coarse spatial resolution of remote sensing data, ii) changes in remotely sensed reflectance data over time, and iii) weak linkages between species counts and spectral diversity in agricultural landscapes. To overcome these limitations, we present three novel spectral diversity approaches: i) a subpixel spectral diversity approach, ii) a multi-temporal spectral diversity approach, and iii) an object-based spectral diversity approach. Here, we provide different case studies using these three spectral diversity approaches to quantify plant diversity in two distinct grassland ecosystems: an agricultural landscape in the Swiss Alps and a tallgrass prairie in Oklahoma, U.S.
Global Projections of Flash Drought in a Warming Climate
Authors: Christian Jordan , Martin Elinor , Basara Jeffrey , Furtado Jason , Otkin Jason , Lowman Lauren , Hunt Eric , Mishra Vimal , Xiao Xiangming
Published: February 2023

As global population continues to rise, the associated demand for agriculture is expected to significantly increase over the next several decades. Furthermore, projected increases in climate variability due to global climate change will impact the cropland expansion and agricultural intensification required to meet the demand in the coming decades. Flash drought presents a unique challenge within the realm of weather and climate extremes. Given their rapid development, drought mitigation strategies are challenging to implement during flash drought because these events often develop with limited warning, while leading to wide-ranging impacts across the land surface. As such, this study seeks to address two key questions on flash drought: 1) What are the trends in flash drought frequency across the globe in a warming climate and 2) how does the risk to cropland from flash drought change in the future? These questions are addressed by identifying flash drought events from six CMIP6 models using the standardized evaporative stress ratio (SESR) and soil moisture. Historical simulations capture the period spanning 1850-2014, while three scenarios are used to project flash drought development under different socioeconomic pathways and radiative forcing levels for the years 2015-2100 (SSP126, SSP245, and SSP585). We find that flash drought occurrence is expected to increase globally among all scenarios, with the sharpest increases seen in scenarios with higher radiative forcing and greater fossil fuel usage. Regionally, the largest projected increases in flash drought occurrence are in Europe and the Amazon. Flash drought risk over cropland is expected to increase globally, with the largest increases projected across North America (change in annual risk from 32% in 2015 to 49% in 2100) and Europe (32% to 53%) in the most extreme SSP585 scenario. Following conservative and medium scenarios compared to high end scenarios indicates a notable reduction in annual flash drought risk over cropland.
Response of soil organic matter turnover to soil salinization and climate warming
Authors: Wang Shang , Razavi Bahar , Spielvogel Sandra , Blagodatskaya Evgenia
Published: February 2023

Climate change is turning soil salinization into a global problem due to the increasing frequency and severity of coastal salt and brackish water ingress. How increasing salinity affects microbial metabolic activity and its consequences for matter and energy turnover under climate warming remain unclear. Thus, we conducted a lab incubation experiment to explore the interactive effects of salinization and warming on microbial and enzymatic functional traits related to the CO2 (matter) and heat (energy) losses in the course of glucose metabolism.Soil from coastal grassland was artificially salinized to, middle (2.06 mS cm-1) and high (3.45 mS cm-1) levels by gradually adding salt solution, while the soil with ambient salinity (0.49 mS cm-1) was defined as control. Effect of realistic warming (+2 ℃) on CO2 emission and heat release from soil amended with glucose was estimated by the respirometer Respicond V and microcalorimeter TAM Air, respectively. Energy and carbon use efficiency, calorespirometric ratio, microbial growth parameters and enzyme kinetics were determined in the salinity gradient.Despite cumulative CO2 emission and heat release were not affected by soil salinity, we observed gradual delay in glucose induced respiration (GIR) and heat release with the increasing salinity level. In contrast, warming facilitated both GIR and heat release, and increased the cumulative CO2 by 8-14%, but had no effect on the cumulative heat.Before glucose addition, high salinity greatly reduced the C-acquiring enzyme activities (β-D-glucosidase, cellobiohydrolase) by 17-39% compared with control, while an activity of the P-acquiring enzyme (acid phosphomonoesterase) notably increased by 24 and 82% under middle and high salinity, respectively. In soil activated with glucose, high salinity greatly increased the activities of both C- and P-acquiring enzymes up to 74 and 30%, respectively, compared with control. Surprisingly, irrespectively of microbial activation by glucose, the N-acquiring enzyme activity (leucine aminopeptidase) was not affected by salinity.The interactive effect of soil salinity and climate warming on the fate of soil organic matter, energy and carbon use efficiency, calorespirometric ratio and microbial community will be discussed in our presentation.
The Atlantic meridional overturning circulation at 35N from deep moorings, floats, and satellite altimeter
Authors: Le Bras Isabela , Willis Joshua , Fenty Ian
Published: February 2023

From 2004 to 2014, the Line W moorings measured a 0.7 Sv/yr slowing of the Deep Western Boundary Current (DWBC) offshore of Cape Cod, Massachusetts. Here, we combine these deep mooring observations with float and satellite altimeter data and find that this DWBC change corresponded to a slowing of the cross-basin Atlantic Meridional Overturning Circulation (AMOC) of about 0.3 Sv/yr. Our AMOC transport time series corresponds well with the ECCO state estimate, particularly when the Line W mooring data influences our reconstruction of upper ocean volume fluxes. We compare our 35N time series with a similar time series at 41N as well as with the 26N RAPID AMOC, and find AMOC declines across datasets during this time period. The relative magnitudes of these declines are consistent with interdecadal variability originating in the Labrador Sea. We find that though our integrated overturning estimate agrees well with ECCO, the structure of the deep flow differs substantially. While we cannot rule out a decreasing AMOC trend during the 20th century, we find that natural variability is too large to detect a net AMOC decrease in direct observations or the ECCO ocean model since 2004.
A revised Greenland ice-core chronology for the last 3800 years: the GICC2
Authors: Sinnl Giulia , Winstrup Mai , Erhardt Tobias , Cook Eliza , Jensen Camilla , Svensson Anders , Vinther Bo , Muscheler Raimund , Rasmussen Sune
Published: February 2023

Ice-core timescales are vital for our understanding of the past climate; hence they should be updated whenever significant amounts of new data become available. Here, the Greenland ice-core chronology GICC05 was revised for the last 3835 years by synchronizing six deep ice-cores and three shallow ice-cores from the central Greenland ice sheet. A new method was applied by combining automated counting of annual layers on multiple parallel proxies and manual fine-tuning. A layer-counting bias was found in all ice cores because of site-specific signal disturbances, therefore the manual comparison of all ice cores was deemed necessary to increase timescale accuracy. After examining sources of error and their correlation lengths, the uncertainty rate was quantified to be one year per century.The new timescale, called GICC21, is younger than GICC05 by about 13 years at 3835 years ago. The most recent 800 years are largely unaffected by the revision. Between 800 and 2000 years ago, the offset between timescales increases steadily, with the steepest offset occurring between 800 and 1100 years ago. Moreover, offset-oscillations of about 5 years around the average are observed between 2500 and 3800 years ago. The non-linear offset behavior is attributed to previous mismatches of volcanic eruptions, to the much more extensive data set available to this study, and to the finer resolution of the new ice-core ammonium matching. By analysis of the common variations of cosmogenic radionuclides, the new ice-core timescale is found to be in alignment with the IntCal20 curve.
V07 Reprocessing of Global Precipitation Measurement (GPM) Mission Data Suite
Authors: Stocker Erich Franz , Kwiatkowski John , Kelley Owen
Published: February 2023

Periodic reprocessing of the complete GPM data suite is an integral part of thescience processing strategy for the GPM mission. The first publicly available data was identified by the data product version V04 in 2014. In 2017 product version V05 for the radiometer products and in 2018 V06 for the radar products were completed.This reprocessing cycle extended the radar data  back to the TRMM era (1997) and radiometer data back to 1987.  It also officially integrated a considerable amount of earlier data into the GPM data suite. Reprocessing cycle V07 began at the end of 2021 with the radar based data and completed in May 2022 with all the radiometer data. The V07 version had significant changes in radar data because of a change in the Ka radar scanning strategy in May 2018 that allowed the Ka radar to cover the  entire swath of the Ku radar. This allowed dual frequency retrieval across the entire Ku swath rather than just in the interior.  The GPROF precipitation retrieval for the radiometers reverted back to a probablistic output. This presentation will summarize these major changes as well as other algorithm changes that improved the precipitation retrieval.  It will  also present other data that the mission makes available to users. 
Understanding storm-time multi-scale ionospheric structures at mid-latitudes
Authors: Aa Ercha , Zhang Shun-Rong , Erickson Philip , Coster Anthea , Goncharenko Larisa
Published: February 2023

The storm-time mid-latitude ionosphere is an important interface in the global geospace dynamic system, which is characterized by energy and momentum ingests at the auroral/polar latitudes. This interface is affected by these high-latitude processes while being adjacent to expanded low-latitude electrodynamic/dynamic disturbances.  In particular, the mid-latitude and subauroral ionosphere can exhibit far more complicated multi-scale density/flow structures and disturbances than might otherwise be expected during geospace storms, such as large-scale and medium-scale traveling ionospheric disturbances (TIDs), storm-enhanced density (SED) plume, and subauroral polarization stream (SAPS). This presentation will describe some recent storm-time observations of these multi-scale ionospheric structures as well as discuss the underlying magnetosphere-ionosphere-thermosphere drivers. These observations provide some new scenarios to advance the current understanding of mid-latitude and subauroral dynamic processes at both large-scale and meso-scale levels.
Long-Term Forecasting of Environment variables of MERRA2 based on Transformers
Authors: Lee Tsengdar , Roy Sujit , Kumar Ankur , Ramachandran Rahul , Nair Udaysankar
Published: February 2023

Transformers in general have shown great promise in the sequence modeling. Recently proposed vision transformer (ViT) by Dosovitskiy et al. has shown optimal performance in image recogining [1]. Fourier Neural operator based token mixer transformers keeping ViT as backbone was proposed by Guibas et. al. has been used for predicting wind and precipitation on ERA5 dataset[2,3]. Following the previous work, we trained the Fourcastnet from scratch on the MERRA2 data set with 3 verticle levels (z450, z500, z550) and 11 variables (adding u, v, and temp). We trained on data from 2005 to 2015 and made predictions by providing the initial conditions from 2017. The prediction was made for 7 days in advance. For the first 24 hours model prediction, mean correlation was 0.998. Root mean squared error (RMSE) 6 hours prediction was 8.779 and for 24 hours was 19.581 on a scale range of -575.6 to 330.6. The model was further tested on 11 variables on the same training data to evaluate prediction of major events like Hurricane. Initial condition for category 5 Hurricane Sep 28, 2016 – Oct 10, 2016 was given to the model. The model was able to predict the hurricane for 18 hours. Further work will be done in order to tune to model and increase more environment variables from MERRA2 to make the prediction more robust and for a longer period.References:1. Dosovitskiy, A., Beyer, L., Kolesnikov, A., Weissenborn, D., Zhai, X., Unterthiner, T., Dehghani, M., Minderer, M., Heigold,G., Gelly, S. and Uszkoreit, J., 2020. An image is worth 16x16 words: Transformers for image recognition at scale. arXivpreprint arXiv:2010.11929.2. Guibas, J., Mardani, M., Li, Z., Tao, A., Anandkumar, A. and Catanzaro, B., 2021, September. Efficient Token Mixing forTransformers via Adaptive Fourier Neural Operators. In International Conference on Learning Representations3. Pathak, J., Subramanian, S., Harrington, P., Raja, S., Chattopadhyay, A., Mardani, M., Kurth, T., Hall, D., Li, Z.,Azizzadenesheli, K. and Hassanzadeh, P., 2022. Fourcastnet: A global data-driven high-resolution weather model usingadaptive fourier neural operators. arXiv preprint arXiv:2202.11214.
Airless body surface weathering by dielectric breakdown
Authors: Jordan Andrew , MacLeod Morgan
Published: February 2023

A number of studies have suggested that dielectric breakdown weathering (“sparking”) may occur on airless bodies in the Solar System. To experience dielectric breakdown, a regolith must be exposed to a sufficiently high fluence of energetic charged particles (>1010 cm-2), and this fluence must be deposited on a timescale less than the regolith’s discharging timescale, which increases with decreasing temperature. Consequently, dielectric breakdown occurs in regolith that is both cold and exposed to high fluxes of solar energetic particles (SEPs) or radiation belt particles. If breakdown occurs, then it causes space weathering by melting and vaporizing microscopic channels through regolith near the surface. We describe our recent experimental, observational, and theoretical work investigating where dielectric breakdown may be an important space weathering process. In the inner Solar System, airless bodies are exposed sporadically to SEP events with high fluences. At 1 AU, the flux of SEPs is nearly isotropic, and thus they may cause dielectric breakdown over the coldest (<120 K) regions of the Moon’s nightside. We present observational evidence for this nightside process and the results of preliminary experiments investigating its microscopic effects. In addition, we briefly discuss the possibility that dielectric breakdown weathering also occurs on Mercury, the moons of Mars, and some asteroids.In the outer Solar System, where the fluxes of SEP events are significantly reduced, dielectric breakdown is more likely to be caused by radiation belts. In particular, moons in Jupiter’s radiation belts are exposed to the highest continuous fluxes of energetic charged particles in the Solar System. Furthermore, Jupiter’s radiation belts have caused dielectric breakdown in spacecraft dielectrics. We describe the range of evidence showing that dielectric breakdown may occur on some of the Galilean moons (Io, Europa, and Ganymede) and Jupiter’s four innermost moons (Amalthea, Thebe, Adrastea, and Metis).
Evolution of the lithospheric mantle beneath Eastern Dharwar craton of Southern India: constraints from peridotite xenoliths from P3 kimberlite pipe of the Wajrakarur
Authors: Daimi Zeeshan , Dongre Ashish
Published: February 2023

Even though the southern Indian Dharwar craton hosts several kimberlites, lamproite, and lamprophyre fields of the Mesoproterozoic age, mantle-derived peridotitic xenoliths are very rare and are often highly altered and poorly preserved. Due to these constraints, xenolith-based direct mantle investigations have been limited beneath the Indian cratons. In this study, we report extensive geochemical analyses on peridotite xenoliths from the P3 kimberlite pipe of the Wajrakarur kimberlite field from the Eastern Dharwar craton (EDC). With the help of major and trace element compositions of the garnets and clinopyroxenes, this study aims to characterize the mantle below EDC and to comment on its evolution.During this study, 57 peridotite xenoliths were identified. P-T estimates were carried out using garnet compositions. Based on the vertical distribution of garnets on a projected depth, it is observed that the upper part of the lithosphere is composed mostly of lherzolites(G9) with few harzburgites (G10), whereas the base of the lithosphere is dominated by Ti-Metasomatized garnets(G11).Garnet compositions show an anomaly in the TiO2 content, which is marked by a sudden increase in TiO2 at ~160 km of depth. This depth coincides with an increased concentration of G11 garnets. Zr/Hf vs Ti/Eu plot for garnets shows that carbonatitic and kimberlitic fluids are involved in metasomatizing the SCLM. The Mg# and Cr# values suggest that the lithosphere gets more depleted with increasing depth. Clinopyroxene compositions show the presence of two types. Type 1 is enriched in LREE than the Type 2 clinopyroxenes showing the metasomatic enrichment.The depth range of the studied peridotite xenoliths indicates sampling of the mantle from ~170 to 190 km of depth, indicating a 190 km thick LAB at 1.1 Ga. However, geophysical studies show a present-day estimate of a ~110 to 120 km thick lithosphere. This further indicates about 70-80 km of delamination of the lithospheric keel in post-Mesoproterozoic times. Such large-scale delamination of the lithosphere might be possible due to the increased frequency of mantle plumes, convective erosion, and the heavily metasomatized nature of the SCLM.
The Emission and Physicochemical Properties of Light-Absorbing Carbonaceous Particles at A Cold-Climate Site
Authors: Li Houjie , Ariya Parisa
Published: February 2023

Aerosols have drawn great scientific interests in the past decades dur to their essential roles in the nucleation of ice, clouds, radiation budget and climate change. Light-absorbing carbonaceous particles (LACs), including black carbon (BC) and brown carbon (BrC), are important radiatively-active aerosols in the atmosphere. In this research, we will present the emissions and physicochemical properties of BC and BrC particles. We will try to figure out the contribution of BC and BrC respectively, by combining results from instrument measurement (photoacoustic extinctiometer and aethalometer) and the analysis of aerosol samples collected on filters (UV/vis spectrometry and LC-TOF-MS). In the end, we would like to show the impacts of LACs in cold-climate sites, comparing with warm-climate sites. 
Interspecific interaction and species identity effects on water uptake of beech and spruce trees by using stable isotope labelling
Authors: Kinzinger Laura Lee , Mach Judith , Haberstroh Simon , Dubbert Maren , Weiler Markus , Orlowski Natalie , Werner Christiane
Published: February 2023

Understanding the interactions within the soil-plant-atmosphere-continuum becomes more important considering the eco- and hydrological impacts of climate change. Especially stand specific flow pathways and the characteristic timescales of water movement potentially provide important information on drought resilience of different forest ecosystems. This study analysed tree stand specific water uptake dynamics through water stable isotopy at high temporal resolution for two isotopic labelling events (7mm with δ2H +1000 ‰ and 23mm with δ2H +800‰) during the 2022 drought in south-west Germany. Measurements in pure and mixed tree stands of European beech (Fagus sylvatica, n=18) and Norway spruce (Picea abies, n=18) included sap flow, in-situ water isotopy of soil and xylem water, radial stem growth and microclimatic conditions. Our central hypothesis is that species identity and water competition between tree species are major drivers for ecohydrological flux dynamics. The results of the two labelling events showed differences in label water uptake of the two tree species and the transit times of the label in the system. The labelling events showed different transit times in the tree xylem depending on the label intensity. P. abies showed a slightly higher uptake of shallow soil water label in mixed stands than in pure patches. When labelled water infiltrated into deeper soil layers water was taken up faster by F. sylvatica in mixed forest patches than in pure forest patches and showed a generally slower uptake in P. abies than in F. sylvatica. The faster response time in water uptake during the second labelling was supported through an increase in measured sap flux and modelled branch water potential. Those dynamics of water isotopy measured in a high temporal resolution allow for a better understanding of root water uptake dynamics and water use strategies but also show species interaction effects on ecohydrological fluxes.
Machine Learning-based Probabilistic Precipitation Estimation with the GOES-16 Advanced Baseline Imager
Authors: Upadhyaya Shruti A. , Kirstetter Pierre-Emmanuel , Kuligowski Robert J.
Published: February 2023

This study introduces a new machine learning-based probabilistic quantitative precipitation estimate (PQPE) retrieval that uses observations from the GOES-16 Advanced Baseline Imager (ABI) across the CONUS at 5 min temporal resolution and ~2 km spatial resolution. It is developed and evaluated using the Ground Validation Multi-Radar/Multi-Sensor (GV-MRMS) system as a benchmark, and features Convolutional Neural Network (CNN) machine learning. Key advances include (1) the design of a three-dimensional CNN model to retrieve the distribution of precipitation rate instead of a single deterministic value; (2) a comprehensive set of predictors based on spatio-temporal information from infrared ABI channels and complemented by environmental conditions from Numerical Weather Prediction (NWP) models; and (3) using probabilities of occurrence for different precipitation type (e.g., convective and stratiform), retrieved from a separate machine learning  model as predictors in the CNN model. Precipitation type predictors allow a single model to be used seamlessly for all precipitation types. The analysis reveals that combining predictors based on satellite and NWP data leads to improved performance, with the greatest improvement in the stratiform precipitation type. The use of probabilities of precipitation type as predictors contributes significantly to the improved performance of the quantitative precipitation retrievals. Furthermore, improvements in conditional biases are demonstrated for all precipitation rates when compared to a deterministic CNN model.
GIS-FSLAM-FORM: A QGIS plugin for fa t probabilistic susceptibility assessment of rainfall-induced landslides at regional scale
Authors: Cui Hongzhi , Hürlimann Marcel , Medina Vicente , Ji Jian
Published: February 2023

Landslide susceptibility analysis is the necessary procedure for timely discovering and locking potential sources of slope instabilities in natural terrain areas. The infinite slope model is broadly applied for evaluating the shallow landslide susceptibility coupling the geotechnical and geological parameters with a hydrological model. Because rainfall is one of the major factors inducing landslides, the calculation of the water table and pore water pressure is an important task in our approach. To assess appropriately the most susceptible areas, we propose a new framework for regional slope stability based on probabilistic analysis by combining a hydromechanical model, which couples the Fast Shallow Landslide Assessment Model (FSLAM) and reliability method. A user-friendly software based on the open-source geographic information system (QGIS) platform called the GIS-FSLAM-FORM plugin adopting the Python programming language was designed and developed. Accounting for the potential uncertainties of geotechnical parameters (in particular effective cohesion and friction of soil or root strength), the horizontal hydraulic conductivity, as well as the soil depth. Our now approach is emphasized for its simple hydrologic model and its high computation efficiency. To consider the probabilistic information of the FSLAM incorporating the infinite slope, the first-order reliability method (FORM) is presented during the analysis although inevitably involving iterative computing. The developed plugin using physically-based modelling can directly provide several regional hazard index distribution maps, such as the factor of safety (FoS), reliability index (RI), and failure probability (Pf).
Global-scale reductions in free tropospheric ozone in 2020-2022 associated with decreased pollution due to COVID-19 and impact on trends
Authors: Ziemke Jerry , Kramarova Natalya , Frith Stacey , Huang Liang-Kang
Published: February 2023

NASA satellite measurements show that ozone reductions throughout the Northern Hemisphere (NH) free troposphere reported for spring-summer 2020 during the COronaVIrus Disease 2019 (COVID-19) pandemic have occurred again in spring-summer 2021.  The satellite measurements show that tropospheric column ozone (TCO) (mostly representative of the free troposphere) for 20oN-60oN during spring-summer for both 2020 and 2021 averaged ~3 Dobson Units (DU) (or ~7-8%) below normal.  These ozone reductions in 2020 and 2021 were the lowest over the 2005-2021 record.  We also include satellite measurements of tropospheric NO2 that exhibit reductions of ~10-20% in the NH in early spring-to-summer 2020 and 2021, suggesting that reduced pollution was the main cause for the low anomalies in NH TCO in 2020 and 2021.  Reductions of TCO ~2 DU (7 %) are also measured in the Southern Hemisphere in austral summer but are not associated with reduced NO2.  We also extend our analyses to show that year 2022 spring-summer anomalies in NH tropospheric NO2 and free tropospheric ozone from the satellite measurements still remained below pre-COVID levels. 
Lessons Learned in V07 IMERG
Authors: Huffman George , Bolvin David , Joyce Robert , Nelkin Eric , Tan Jackson
Published: February 2023

The Global Precipitation Measurement (GPM) mission combines passive microwave (PMW) and infrared (IR) satellite data, together with other data to create the Integrated Multi-satellitE Retrievals for (IMERG) precipitation product on a (nearly) global 0.1° half-hour grid.  Experience with Version 06 datasets revealed deficiencies that the algorithm team has addressed in creating the new Version 07 datasets.Input precipitation estimates from the Goddard Profiling (GPROF) algorithm (which retrieves precipitation from passive microwave sensor data), the GPM Combined Radar-Radiometer Algorithm (CORRA), and the new Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks–Dynamic Infrared Rain Rate (PDIR) algorithm (retrieving precipitation from IR data) all represent advances over the V06 inputs.  For V07, several issues have been addressed, and many algorithm improvements have been implemented.  These include refining the Kalman filter to approximately preserve the local histogram of precipitation rates (Scheme for Histogram Adjustment with Ranked Precipitation Estimates in the Neighborhood, or SHARPEN), and applying the Kalman filter even when a PMW overpass occurs.  Furthermore, a long-standing bug in the geolocation that shifted grid values 0.1° to the east in the latitude band 70°N-S has been corrected.  Other changes in V07 include a hierarchical selection among motion vector sources to address deficiencies in the precipitation propagation near orography, an update to the precipitation phase specification for improved consistency with current inputs, and climatological adjustment of the near-real-time Early and Late Runs to the Final Run (which includes monthly precipitation gauge analyses).  Extensive development work was directed at unexpected biases in the V06 products, leading to 1) calibrations that now employ the entire swath widths of CORRA and GPROF GPM Microwave Imager (GMI) precipitation estimates (rather than spatially coincident data), and 2) coarsening the CORRA resolution to approximately match the GPROF-GMI footprint scale.  The latter provides more consistent histograms for building the calibrations.It is anticipated that the retrospective analysis for V07 will be well underway at the time of the meeting.  Changes between V06 and V07 will illustrate the cumulative result of the improvements implemented in V07.  The current status of processing and plans for future development will also be discussed.
Natural production of nitrate by groundwater nitrification in New Zealand karst springs
Authors: Stewart Michael , Hickey Chris , Moreau Magali , Thomas Joseph , Young Roger
Published: February 2023

The objective of this work is to understand the sources of nitrate in Te Waikoropupū Springs (‘the springs’) in New Zealand, and thereby contribute to their preservation. Previous work has shed light on the recharge sources of water to the springs (Stewart and Thomas, 2008), and nitrate mass balance based on this recharge model reveals the nitrate values in the recharge waters when they reach the springs. The major recharge source (from pristine forest on karst uplands) delivers much more nitrate to the springs than expected from measurements on water in its recharge area. This excess nitrate is attributed to nitrification (following mineralisation of organic-N) within the oxic karst groundwater system as the water flows to the springs.Nitrification (bacterial conversion of ammonium to nitrate) is widespread in soils, unsaturated zones and oxic groundwater systems. Evidence showing natural production of nitrate by nitrification in the current system is given by: (1) Total nitrogen measurements: If organic-N is converted to nitrate-N along the flowpath from the Karst Uplands to the springs, there must be input of 5 kg/ha/yr of organic-N from the recharge area of 170 km2. This is within the range found by McGroddy et al. (2008) for first order streams from pristine forests in NZ. (2) 15N and 18O measurements: Nitrification produces nitrate with low values of the isotope ratios as observed for the springs, whereas denitrification would cause high values which are not observed. (3) Scientific literature: Recent papers have reported nitrification as a previously unrecognised source of nitrate in oxic karst systems. For example: Musgrove et al. (2016) showed that groundwater nitrate concentrations in the Edwards Aquifer were higher than those in the surface water recharge. They concluded that nitrification within the aquifer is the source of the extra nitrate in the groundwater.ReferencesMcGroddy, M.E., Baisden, W.T., Hedin, L.O. 2008. Global Biogeochemical Cycles 22, GB1026.Musgrove, M., Opsahl, S.P., Mahler, B.J., Herrington, C., Sample, L.L., Banta, J.R. 2016.  Science of the Total Environment 568, 457–469.Stewart, M.K., Thomas, J.T. 2008. Hydrology and Earth System Sciences 12(1), 1-19.
Numerical modelling of seismic field record with elastic velocity construction for CO2 sequestration in offshore, South Korea
Authors: Cheong Snons , Kang Moohee , Kim Kyoung Jin
Published: February 2023

To evaluate the feasibility of CO2 sequestration in offshore, South Korea, we studied numerical modelling with elastic velocity model. The CO2 storage candidate is a brine saturated aquifer formation overlain by basalt caprock in the Southern Continental Shelf of Korea. Basalt formation without joint and fracture can seal a storage volume preventing leakage of injected CO2. Result of preliminary two-dimensional seismic exploration estimated that storage potential would be from 42.07 to 143.79 Mt of CO2. The input model include P- and S-wave velocity and density of shallow sediment and vasalt layer. To simulate CO2 injection, we assumed an area of CO2 plume at the interval beneath the depth of basalt formation and artificially decreased P-, S-wave velocities, and density values. Synthesized seismic records are comparable with survey's gather as direct arrival and primary reflections. The ongoing work can be extended on a quantitative verification concerning serveral cased of varying velcoties and densities.