bluuebunny/crossref_metadata_2025 huggingface dataset:
Advancing Precipitation Measurements from the NASA TROPICS Mission.
Authors: Kidd Chris , Matsui Toshi , Blackwell William , Braun Scott , Leslie Robert , Griffith Zach
Published: February 2023

A major challenge for measuring precipitation from space is the need to properly capture the spatial and temporal variability of precipitation. This requires that all available observations from precipitation-capable sensors are exploited. Passive microwave sensors are fundamental in providing reliable observations since they relate to the precipitation particles themselves. Passive microwave sounding instruments have been developed for cubesats, such as for the Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission. The TROPICS pathfinder was launched in June 2021 into a polar orbit, carrying the TROPICS Millimeter-wave Sounder (TMS) with frequencies ranging from 91.655 to 204.8 GHz. The Precipitation Retrieval and Profiling Scheme (PRPS) has been adapted for use with the TMS based upon a 4-channel ATMS-DPR a priori database. This surrogate database is built upon coincident observations from the NPP and NOAA-20 ATMS sensors and the precipitation retrievals from the GPM DPR. The main limitation of the current database is that it is limited to just four closely matched channels, one at 89/91 GHz and the three around the 183.31 GHz water vapour absorption lines. The limited number of TMS vs DPR observations early in the mission precluded their use to generate a viable database: however, a reasonable number of coincident observations are now available to provide an insight into the use of the full range of TMS channels in the retrieval scheme. A total of about 1200 coincident TROPICS/GPM overpasses are available since launch, providing about 2 million matched footprints. Comparisons between the full 12-channel TMS database and the 4-channel ATMS database show a good degree of improvement, although refinement of channel weighting is deemed necessary, not least due to the high inter-channel correlations present within the 118 and 183 GHz channel groups. However, validation of the resulting precipitation products against the IMERG precipitation product indicate that the retrievals from the TMS are comparable as those from similar cross-track sounding instruments (such as GPROF retrievals from the MHS and ATMS).
Evaluating the risk of cumulative impacts in the Mediterranean Sea using a Random Forest model
Authors: Bianconi Angelica , Furlan Elisa , Simeoni Christian , Pham Vuong , Vascon Sebastiano , Critto Andrea , Marcomini Antonio
Published: February 2023

Marine coastal ecosystems (MCEs) are of vital importance for human health and well-being. However, their ecological condition is increasingly threatened by multiple risks induced by the complex interplay between endogenic (e.g. coastal development, shipping traffic) and exogenic (e.g. changes in sea surface temperature, waves, sea level, etc.) pressures. Assessing cumulative impacts resulting from this dynamic interplay is a major challenge to achieve Sustainable Development Goals and biodiversity targets, as well as to drive ecosystem-based management in marine coastal areas. To this aim, a Machine Learning model (i.e. Random Forest - RF), integrating heterogenous data on multiple pressures and ecosystems’ health and biodiversity, was developed to support the evaluation of risk scenarios affecting seagrasses condition and their services capacity within the Mediterranean Sea. The RF model was trained, validated and tested by exploiting data collected from different open-source data platforms (e.g. Copernicus Services) for the baseline 2017. Moreover, based on the designed RF model, future scenario analysis was performed by integrating projections from climate numerical models for sea surface temperature and salinity under the 2050 and 2100 timeframes. Particularly, under the baseline scenario, the model performance achieved an overall accuracy of about 82%. Overall, the results of the analysis showed that the ecological condition and services capacity of seagrass meadows (i.e. spatial distribution, Shannon index, carbon sequestration) are mainly threatened by human-related pressures linked to coastal development (e.g. distance from main urban centres), as well as to changes in nutrient concentration and sea surface temperature. This result also emerged from the scenario analysis, highlighting a decrease in seagrass coverage and related services capacity, in both 2050 and 2100 timeframes. The developed model provides useful predictive insight on possible future ecosystem conditions in response to multiple pressures, supporting marine managers and planners towards more effective ecosystem-based adaptation and management measures in MCEs.
Multidisciplinary reconstruction of the flood episode of September 1793
Authors: Gimenez-Font Pablo , Barriendos Josep , Olcina Jorge , Barriendos Mariano , Balasch Josep Carles , Tuset Jordi
Published: February 2023

Climate variability conditioned by the effects of climate change justifies the study of past periods in order to identify and characterise episodes of high severity and low frequency. The increase in the irregularity of the precipitation regime in some regions justifies the study of these events for a better assessment of their occurrence in the immediate future. In this regard, the climatic framework of the Maldà Oscillation (1760-1800) offers hydrometeorological anomalies of low frequency and high severity, especially in the dimension of catastrophic floods. One of the episodes that occurred in this period affected the region of the present-day Valencian Community, on the eastern coast of the Iberian Peninsula, between 6 and 8 September 1793.The aim of this work is to reconstruct, in as much detail as possible, the meteorological and hydrological behaviour of an extraordinary rainfall event. At the same time, it also aims to reconstruct the impacts caused on human activity. In order to achieve this objective, data from old instrumental meteorological observation and the result of an extensive collection of information from historical documentary sources are used. Although the meteorological data are scarce, they allow the synoptic characterisation of the episode. The hydrological approach of the episode is only qualitative, but it allows the identification of the affected river basins and the occurrence of river floods and overflows. The social impacts of the episode are significant and occurred due to the exceptional nature of the episode. For example, the overflowing of the top of a hydraulic dam built at the end of the 16th century (Tibi dam, 43 metres above the river course). Despite the presence of hydraulic infrastructures that were able to control the floods, there were numerous catastrophic damages that are represented in a detailed thematic cartography. During 3 days of flooding, 7 river basins belonging to the Júcar and Segura hydrographic demarcations were affected, with 11 towns and villages suffering catastrophic damages. Likewise, the social response to these events is analyzed, basically characterized by the celebration of religious ceremonies.
Interdependence among subregional crop production affects global crop failure risk
Authors: Feng Sifang , Zscheischler Jakob , Hao Zengchao , Bevacqua Emanuele
Published: February 2023

Synchronous crop failure among multiple breadbaskets worldwide, a typical spatially compound event, may amplify threats to the global food system and food security and has been a growing concern among the scientific community in recent years. While the risk of simultaneous crop loss across multiple breadbasket regions has been analyzed, to date, little is known about how interdependence among regional crop production affects aggregated crop failure at the global scale. Quantifying the impact of dependencies among breadbasket regions on global food production and assessing how the dynamic of spatially compounding crop failures is simulated by climate and crop models is essential for informing the modeling of global food security risk. In this study, focusing on different crop types, we quantify the influence of dependence between crop production of individual regions on global aggregated crop yield based on the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) dataset. We find that spatial dependence between regional crop yields may aggravate global crop deficits and identify a characteristic spatial scale beyond which the dependence between crop production in different regions vanishes. Our results provide valuable information for designing risk strategies for food security at the suited scale.
Southwestward tilting of the Ordos Loess Plateau, central China: topographic response to India-Asia convergence deduced from drainage systems
Authors: Duan Mengyue , Neubauer Franz , Robl Jörg , Zhou Xiaohu , Liebl Moritz , Argentin Anne-Laure , Dong Yunpeng , Boekhout Flora
Published: February 2023

The Ordos Loess Plateau with its iconic fluvial incision pattern represents an uplifted but internally stable plateau crustal block on the eastern fringe of the Tibetan Plateau. The Ordos Loess Plateau deeply incised river landscapes and hence its inaccessibility helped to protect ancient China from invading nomads from the north. The Ordos Block is internally free of seismicity but its boundaries feature severe high-magnitude earthquakes. Due to the ongoing India-Asia convergence, the northeastward expansion of the Tibetan Plateau leading to the eastward lateral extrusion of fault-bounded blocks. The Ordos Loess Plateau is part of one of these blocks and is still affected by lateral eastward motion along crustal scale faults and large surface uplift from Late Miocene to present. In this study, we investigated the effect of fault activity on the morphological evolution of the Ordos Loess Plateau. To quantify the effect of uplift gradients on the drainage systems, we investigated topographic patterns and landform metrics through field surveys and topographic analysis based on digital elevation models. Field surveys show that the southern boundary of the Ordos Loess Plateau to the Weihe Graben is still tectonically active (evidence for faulting in quaternary sediments). We found that the drainage is consistently directed towards the Weihe Graben in the southeast. Fluvial channels are in a state of morphological disequilibrium, with steep channel segments towards the Weihe Graben and meandering low gradient rivers in the central Ordos Loess Plateau. Over substantial portions, the shape of the longitudinal channel profile in the Ordos Loess Plateau is straight and deviates from usual graded longitudinal channel profiles. We further found that the degree of erosion and plateau incision is pronounced in the eastern part of the Ordos Loess Plateau, while the southwestern part is less incised. The drainage network indicated that the drainage basins are tilted toward the Liupanshan Mountains overthrust in the southwest. We conclude that the far-field influence of the Cenozoic uplift of the Tibetan Plateau activated the southwestern and southern boundary faults around the Ordos Loess Plateau. The drainage systems reorganized to a principal southern flow direction and thereby progressively incised in the Ordos Loess Plateau, causing severe soil erosion.
Kinematics at the Muragl rock glacier in Switzerland
Authors: Cathomen Sandro , Junghardt Johann , Gärtner-Roer Isabelle
Published: February 2023

To determine the influence of climate warming on permafrost, creep velocities of rock glaciers are a reliable measure, as they indirectly reflect the thermal conditions of a rock glacier. In this study, the kinematic and morphological characteristics of Muragl rock glacier in Switzerland were investigated using UAV images from 2015 and 2022, and correlations to changing ground surface and air temperatures over the same period were examined. Data collection was performed using repeated UAV surveys, annual terrestrial surveying, and continuous logging of ground surface temperatures. The collected data sets from the different methods were compared and tested for similar patterns in the rock glacier kinematics. The comparison of the UAV surveys and the terrestrial measurements showed heterogeneous patterns of the landform and agree with previous investigations. The central part of the rock glacier and the northern outburst lobe show higher velocities than the rest of the landform. Locally, creep velocities of up to 13.61m in seven years were calculated and the mass movements in the model of the creep behavior displayed surface changes up to 4m. The velocities of the individual years showed correlations with the average temperature measured in Switzerland. The change of the creep velocity during the mild and snow-poor winter of 2019/2020 was particularly recognizable. Furthermore, the creep velocities at Muragl rock glacier are relatively high in comparison to other rock glaciers in the region. Additionally, correlations between rising average temperatures in Switzerland, ground surface temperatures and the creep velocity at the Muragl rock glacier were clearly recognizable. The results of this study are advantageous to describe sensitivies of the cryosphere.
Flocculation of trace metals from boreal acid sulphate soils over an estuarine gradient
Authors: Virtasalo Joonas , Österholm Peter , Asmala Eero
Published: February 2023

Among the most important processes affecting the global biogeochemical cycles of carbon, nutrients and trace metals is the physicochemical transformation of terrestrial dissolved and colloidal material into suspended particles in estuaries. The gradient of increasing salinity and pH towards seawater induces the flocculation of riverine dissolved organic matter to the particulate form, providing a mechanism for the capture of dissolved metals to the newly formed particles. The role of pH is particularly relevant in the context of acid sulphate (AS) soils that can generate extremely low pH conditions and high soluble trace metal concentrations in river waters.This study investigated organic matter flocculation, and trace metal (Al, Fe, Co, Mn and Cu) association with the newly formed organic particles, by the mixing of natural acidic river water and synthetic seawater in the laboratory. River water was collected from the Laihianjoki and Sulvanjoki rivers that are among the most AS-soil-impacted rivers in Finland and Europe. Continuous bucket experiments with an in situ LISST-100X particle size distribution analyser and YSI EXO2 multiparameter water quality sonde were run to simulate the development of suspended particle pool over the local salinity gradient from 0 to 6. Jar experiments with discrete salinity treatments were carried out to investigate metal behaviour with the collection of flocculated material on glassfibre filters. The filter samples were subjected to persulfate digestion of organic particles and metal oxyhydroxides (pH <2.3) and the digestion supernatants were analysed for metal concentrations by ICP-MS.It was found that Al and Fe were strongly transferred to the particle pool and captured in large (>80 µm) organic flocs already in the lowest salinity range from 0 to 2, with a slightly lower transfer rate at higher salinities. The increasing concentration of small (median 11 µm) flocculi particles above pH ca. 5.5 (salinity 1 in Laihianjoki, salinity 2 in Sulvanjoki) indicate that the precipitation of Al and Fe oxyhydroxides contributed to the particle pool as a minor component. Co and Mn were weakly associated with organic complexes and relatively persistent in solution; however, the transfer of Co to the particle pool was roughly twice of that of Mn, indicating at least partial decoupling of Co from Mn oxyhydroxide precipitation. Cu to a significant proportion (<60 %) was bound to organic particles in the acidic and humic-rich rivers, and this proportion did not change significantly during mixing with seawater. The findings of this study demonstrate that salinity and pH in the estuarine mixing are important controls for the seaward transport and environmental impacts of metal loading from boreal AS-soil-impacted rivers.
The record of the Middle Eocene Climate Optimum in the carbonate platforms of the South Pyrenean Basin (Santo Domingo, External Sierras)
Authors: Garcés Miguel , López-Blanco Miguel , Silva Roi , Juvany Philemon , Arbués Pau , Pueyo Emilio , Beamud Elisabet
Published: February 2023

The Middle Eocene Climate Optimum (MECO) was a 0.5 Myr warming interval that punctuated the long-term cooling trend of the middle to late Eocene. It has been identified worldwide by a gradual negative shift of the dO18 followed by a sharp return to the cooling trend. The peak warming at about 40 Ma coincides in some records with a sharp negative excursion of the d13C, which suggested a relation of the warming event with a transient increase of pCO2. Results from various records also point to increased seasonality and chemical weathering of the source area in coincidence with the MECO.The interval of the MECO is stratigraphically well constrained in the south-central Pyrenees, from the Graus-Trempto the Aínsa and Jaca basins thanks to previous biostratigraphic and magnetostratigraphic investigations. During this period, the south-Pyrenean foreland formed a narrow and shallow elongated basin connected to the west to the Atlantic Ocean. Here we present a record of the MECO in the carbonate platform succession (the Santo Domingo Member of the Arguis Fm.), that accumulated on the Iberian foreland margin, currently outcropping along the External Sierras (the frontal thrust sheet of the southern Pyrenees). Polished samples were micro-drilled to analyse the d18O and d13C isotopes ratios separately from the mud fraction and shells of different species of larger benthic foraminifera. The results show trends of the d18O from the mud fraction that parallel the global ocean isotope signature but with values that are offset towards more negative values (-4‰). There, the influence of the continental waters in the isotopic signal was possibly amplified by the restricted marine paleogeographic context.  Results from fossil shells gave values significantly different from the mud fraction: d18O from Nummulites shells were consistently offset towards more positive values compared to mud, which could indicate a different fractionation pathway or, alternatively, a preferred diagenetic alteration of fossil fragments. A sharp negative excursion of the d13C was identified in coincidence with the negative d18O peak, marking the location of the MECO. Noticeably, a short-lived entry of siliciclastics that replaced carbonate deposition is recorded at the time of the MECO peak, a feature comparable to what is documented in other sections of the eastern Jaca Basin, where a rapid pulse of deltaic sediments (Sabiñánigo sandstone) are embedded within a thick marine marl succession. Our observations agree with a scenario of perturbation of the hydrological cycle and transient increase of sediment discharge from the continent in coincidence with the MECO.
Regionalized design rainfall curves for Greece
Authors: Iliopoulou Theano , Koutsoyiannis Demetris , Koukouvinos Antonis , Malamos Nikolaos , Tepetidis Nikolaos , Markantonis David , Dimitriadis Panayiotis , Mamassis Nikos
Published: February 2023

We perform a large-scale assessment of the probabilistic behaviour of rainfall extremes over the Greek territory aiming to construct a national model for design rainfall. To this aim, we employ multiple sources of rainfall data: from long-term daily records to samples of multi-scale annual maxima, reanalysis rainfall products and satellite information. We identify suitable probability distributions for the multi-scale rainfall extremes useful for design rainfall estimation and regionalize their parameters over Greece using two-dimensional multivariate smoothing techniques. Unique insights are derived regarding the spatio-temporal variability of extreme rainfall over the Greek area, notable for its highly variable topography and climate.
Perturbation of ice sheet surface stress via basal lubrication
Authors: Rines Joshua , Lai Yao , Wang Yongji
Published: February 2023

Surface meltwater on the Greenland Ice Sheet (GrIS) can lubricate the bottom of the ice sheet via surface-to-bed pathways, such as moulins and vertical hydrofracture. The basal lubrication reduces the friction between the ice and the bed, which leads to perturbations in the velocity, strain rate, and stress fields that are felt laterally away from the location of the basal water as well as through the entire thickness of the ice column up to the surface.  In some instances, the induced surface stress may be sufficient to break new cracks, leaving the GrIS more vulnerable to rapid lake drainage via hydrofracture.  It is therefore important to understand the dominant physical parameters which control the magnitude and spatial extent (i.e. the coupling lengthscale) of stress perturbations induced by the basal meltwater lubrication.  To constrain the importance of surface slope, bed slope, and ice thickness as controls on this stress response, we used a 2D simulation of Stokes flow over a slippery patch with various basal boundary conditions, simulating the presence of meltwater lubrication.  We found that the magnitude of the stress response scales with the surface slope while the coupling lengthscale scales with the ice thickness.  This indicates that inland ice may experience a weaker but longer-range stress perturbation in response to water lubrication at the bed.
Modeling global vegetation processes and hyperspectral canopy radiative transfer using CliMA Land
Authors: Wang Yujie , Braghiere Renato , Bloom Anthony , Frankenberg Christian
Published: February 2023

Recent progress in satellite observations has provided unprecedented opportunities to monitor vegetation activity at global scale. However, a major challenge in fully utilizing remotely sensed data to constrain land surface models (LSMs) lies in inconsistencies between simulated and observed quantities. For example, gross primary productivity (GPP) and transpiration (T) that traditional LSMs simulate are not directly measurable from space, although they can be inferred from spaceborne observations using assumptions that are inconsistent with those LSMs. In comparison, canopy reflectance and fluorescence spectra that satellites can detect are not modeled by traditional LSMs. To bridge these quantities, we presented an overview of the next generation land model developed within the Climate Modeling Alliance (CliMA), and simulated global GPP, T, and hyperspectral canopy radiative transfer (RT; 400--2500 nm for reflectance, 640--850 nm for fluorescence) at hourly time step and 1 degree spatially resolution using CliMA Land. CliMA Land predicts vegetation indices and outgoing radiances, including solar-induced chlorophyll fluorescence (SIF), normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and near infrared reflectance of vegetation (NIRv) for any given sun-sensor geometry. The modeled spatial patterns of CliMA Land GPP, T, SIF, NDVI, EVI, and NIRv correlate significantly with existing data-driven products (mean R2 = 0.777 for 9 products). CliMA Land would be also useful in high temporal resolution simulations, e.g., providing insights into when GPP, SIF, and NIRv diverge.
Sediment dynamics related to the triggering of debris flows in different alpine watersheds
Authors: Kaitna Roland , Aigner Philipp , Bernardi Tazio , Wagner Philipp , Kuschel Erik , Zangerl Christian , Hrachowitz Markus , Sklar Leonard
Published: February 2023

Debris flows initiate by a critical combination of abundant sediment, steep inclination, and water. The latter is mostly provided by rainfall that can lead to landslides at the hillslope or along the channel and/or erosion and bulking of sediment due to increased runoff. Location of sediment sources and channel recharge are related to short- and long-term geomorphological processes within the watershed. Up to now, there are only a few studies investigating sediment dynamics in high alpine watersheds that are regularly affected by debris flows. In this contribution we report of our ongoing efforts to monitor sediment dynamics and debris-flow activity in three very different watersheds in the Austrian Alps. We use a combination of remote sensing and in-channel monitoring techniques including UAV, air-borne and terrestrial laser scanning before and after debris-flow events. We find that debris-flows frequency and volumes are strongly related to movement rates of landslides present in the watershed. At high movement rates, most of the channel refill occurs within the time scale of hours. In the absence of active landslides, debris-flow activity is limited by rainfall-triggered embankment failures along the channel and continuous transfer of hillslope sediment into the channel. In the steepest and smallest monitored watershed, active landslides and continuous surface erosion from landslide scars leads to a high frequency of debris flows of all magnitudes, even in the absence of rainfall. Our study shall provide the basis for a more complete modeling framework for a better prediction of debris flows now and in a future climate. 
Physical Disturbances to Soil Homogenize Bacterial Communities via Dispersal and Selection within Microaggregate Fractions
Authors: West Jaimie , Lauer Joseph , Herrick Bradley , Whitman Thea
Published: February 2023

Soil aggregation physically protects soil organic matter and promotes soil carbon persistence through microaggregate formation and organo-mineral associations, in concert with soil microbial community activity. Soil aggregates are sensitive to physical disturbances due to management, bioturbation, and intrinsic factors like root growth and freeze-thaw cycles, all of which affect soil microhabitat conditions, resource availability, and microbial interactions. Using 16S rRNA gene sequencing, we explored how tillage in agricultural systems and Amynthas spp. earthworm bioturbation in woodland systems affected the bacterial community composition of different soil microaggregate fractions (free in the soil vs. occluded within macroaggregates) isolated via wet sieving. We then inferred ecological community assembly processes using phylogenetic distance and community dissimilarity metrics in a null-modelling approach. Our results suggest that mixing disturbances homogenized bacterial communities, as quantified by increased compositional similarity across both within-plot and between-plot scales. Findings also indicate increased influences of homogenizing dispersal and homogeneous selection. Contrary to our hypothesis, we did not find major distinctions between the communities of the free and occluded microaggregate fractions. In the agricultural tillage system, this suggests that soil microaggregates may shift between these operationally defined fractions following crop senescence and seasonal changes. In the woodland bioturbation system, microaggregate results reflect biogenic aggregate formation, which is distinct from the pedogenic aggregate processes that may differentiate the free and occluded microaggregate pools. This study improves our understanding of microbial community responses to soil disturbance, and thus the potential mechanisms through which physical disturbances affect soil carbon persistence.
Observations of energetic particles at interplanetary shocks with Solar Orbiter
Authors: Trotta Domenico , Horbury Timothy , Hietala Heli , Dresing Nina , Vainio Rami , Kilpua Emilia , Dimmock Andrew , Blanco-Cano Xochitl , Lario David , Koval Andriy , Wimmer-Schweingruber Robert , Berger Lars , Yang Liu
Published: February 2023

Interplanetary (IP) shocks are important sites of particle acceleration in the Heliosphere and can be observed in-situ utilizing spacecraft measurements. Such observations are crucial to address important aspects of energy conversion for a variety of astrophysical systems.Under this point of view, Solar Orbiter provides observations of interplanetary shocks at different locations in the inner heliosphere with unprecedented time and energy resolution in the suprathermal (usually above 50 keV) energy range. We present a comprehensive identification of such shocks, highlighting their typical parameters.We then study a strong shock showing novel dispersive signals in the suprathermal particle fluxes observed by the Solar Orbiter SupraThermal Electron and Proton sensor. These are probably due to irregular injection of particles to suprathermal energies along the shock front, as inferred using the Solar Orbiter in-situ observations and self-consistent, kinetic modelling of the shock transition.
Infra-AUV Project – Provision of measurement traceability for sound and vibration measurements in the very low frequency range.
Authors: Ceranna Lars ,   InfraAUV-Project-Team
Published: February 2023

Metrology – the science of measurement – has an important role in all fields of science and technology. Core concepts of measurement traceability and measurement uncertainty are vital for measurements to be physically meaningful and for data to be quantified with known levels of confidence. Metrology considerations begin with primary measurement standards; the definitive realisation of a particular quantity that underpins all subsequent measurements of that quantity. Primary standards for sound pressure and acceleration have long been established but historically, have not extend to the relevant frequency ranges in many geophysical applications utilizing seismic, infrasonic, and hydroacoustic technologies, including IMS applications. A European research project called Infra-AUV has recently developed new primary measurement standards for infrasound and for low-frequency seismic measurements, as well as the means to transfer these to enable the calibration of sensors in the field, as required at stations in the IMS network. New calibration capabilities and application-focussed case studies emerging from the Infra-AUV project will therefore be presented, together with the potential consequences and benefits for users of such sensor systems. 
Can Normalizing Flows make Uncertainty Quantification Practical for Time-Lapse Seismic Monitoring
Authors: Sun Changxiao , Malcolm Alison , Kumar Rajiv
Published: February 2023

Due to the nonlinearity of inversion as well as the noise in the data, seismic inversion results certainly have uncertainties. Whether quantifying these uncertainties is useful depends at least in part on the computational cost of computing them.  Bayesian techniques dominate uncertainty quantification for seismic inversion.  The goal of these methods is to estimate the probability distribution of the model parameters given the observed data. The Markov Chain Monte Carlo algorithm is widely employed for approximating the posterior distribution. However, generating the posterior samples by combining the prior and the likelihood is intractable for large problems and challenging for smaller problems. We apply a machine learning method called normalizing flows, which consists of a series of invertible and differentiable transformations, as an alternative to the sampling-based methods. In our work, the normalizing flows method is combined with full waveform inversion(FWI) using a numerically exact local solver to quantify the uncertainty of time-lapse changes. We integrate uncertainty quantification(UQ) and FWI by estimating UQ on the images generated by FWI making it computationally practical. In this way, a reasonable posterior probability distribution is directly predicted and produced by transforming from a normal distribution, measuring the amount and spread of variation in FWI images by sample mean and standard deviation. In our numerical results, the method for calculating the posterior distribution of the model is verified to be practical and advantageous in terms of effectiveness.
Investigation of 3D-effects for UV/vis satellite observations of volcanic plumes
Authors: Wagner Thomas , Warnach Simon , Beirle Steffen , Bobrowski Nicole , Puķīte Janis , Roberts Tjarda , Surl Luke , Theys Nicolas
Published: February 2023

Usually, horizontally homogenous atmospheric properties are assumed for the analysis of satellite observations of atmospheric trace gases. While for most atmospheric quations, this simplification causes only small to moderate errors, for the observation of volcanic plumes this neglecting 3D effects can lead to very large errors. These errors (3D effects) can become especially important for satellite observations with high spatial resolution like TROPOMI on Sentinel-5 Precursor.Different 3D effects were recently investigated for volcanic plumes by Wagner et al. (2022). It was found that especially the so-called light mixing effect can lead to a strong underestimation of the true trace gas amount of volcanic plumes if 1D atmospheric properties were assumed in the retrieval. For strong absorbers like SO2, the underestimation can further be increased by the saturation effect. In that study, different 3D effects were separately studied for idealised plumes.Here we investigate the combined 3D effects for realistic volcanic plumes using radiative transfer simulations. We focus on two scenarios: first on observations of the ascending part of the plume above a volcano and second on the horizontally advected plume at a distance from the volcanic vent. In addition to the 3D effect of the volcanic plume (trace gases and aerosols), also the influence of the surface elevation is investigated. Wagner, T., Warnach, S., Beirle, S., Bobrowski, N., Jost, A., Puķīte, J., and Theys, N.: Investigation of 3D-effects for UV/vis satellite and ground based observations of volcanic plumes, Atmos. Meas. Tech. Discuss. [preprint], https://doi.org/10.5194/amt-2022-253, in review, 2022.
Optimal geometry for reference frame rotation transformation using VLBI-GNSS space-tie onboard Galileo satellites
Authors: Sert Hakan , Hugentobler Urs , Karatekin Ozgur , Dehant Veronique
Published: February 2023

Each space geodetic technique realizes its own technique-specific terrestrial frame. Combining the individual techniques requires the links between those frames such as the local tie vectors. Co-location of different geodetic techniques on Earth orbiting satellites offers the unique opportunity of continuously measure ‘space-ties’ which can have a critical role for achieving the Global Geodetic Observing System (GGOS) goal of 1mm accuracy and 0.1mm/year stability of the Terrestrial Reference Frame (ITRF).We simulate Very Long Baseline Interferometry (VLBI) observations of a broadband VLBI transmitter (VT) onboard Galileo satellites to evaluate the contribution of such a VT space-tie on the rotation transformation between the VLBI and GNSS frames. We investigate the contribution of a VT as space tie by evaluating the formal precision of orientation parameters between the VLBI and GNSS frames using different ground stations/baselines to find the observation geometry for the rotation transformation.
Advancements in RUC Snow Model for Implementation in the Regional Application of the Unified Forecasting System (UFS)
Authors: Smirnova Tatiana , Kliewer Anton , He Siwei , Benjamin Stan
Published: February 2023

RUC land surface model (LSM) was designed for short-range weather predictions with an emphasis on severe weather. The model has been operational at NCEP since 1998. Currently it is utilized in the operational WRF-based Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) regional models. Being available to the world WRF community, RUC LSM is also used as a land-surface component in operational weather prediction models in Austria, New Zealand and Switzerland.At present time, RUC LSM is being tested in the regional application of the UFS-based Rapid Refresh FV3 Standalone (RRFS) model to replace operational RAP and HRRR at NCEP.RUC LSM has improved and matured over the years. The unique feature of this land-surface model is continuous evolution of soil/snow states within moderately coupled land data assimilation (MCLDA). To avoid possible drifts, this feature requires high skill from RUC LSM as well as accurate atmospheric forcing. Continuous snow cycling includes the following snow state variables: snow cover fraction, snow depth, snow water equivalent and snow temperature. To avoid possible inaccuracies in the location of cycled snow on the ground, snow depth is corrected daily using 4-km IMS snow cover information. Work is also underway to further improve RUC snow model for better surface predictions over snow-covered areas. RUC snow model uses “mosaic” approach to account for subgrid variability of snow cover. Within this approach, snow-covered and snow-free portions of the grid cells are treated separately in the solution of energy and moisture budgets. Thus, snow cover fraction becomes a critical parameter, and modifications to its computation have been developed and tested in the RRFS retrospective experiments. Results from these validation experiments will be presented at the meeting.
The Seasonal and Diurnal Variation of Water Vapor as Observed by the Emirates Mars Infrared Spectrometer (EMIRS)
Authors: Smith Michael , Badri Khalid , Atwood Samuel , Edwards Christopher , Christensen Philip , Wolff Michael
Published: February 2023

Thermal infrared spectra taken by the Emirates Mars Infrared Spectrometer (EMIRS) enable the retrieval of atmospheric temperature profiles from near the surface to ~40 km, and the column abundance of dust aerosols, water ice clouds, and water vapor. A constrained linear inversion retrieval routine that includes multiple scattering has been developed and optimized for this purpose. The unique, high-altitude orbit of the Emirates Mars Mission (EMM) enables sampling of all local times over a wide range of latitudes and longitudes over a short sub-seasonal timescale of less than two weeks. Observations from the Science Phase of EMM cover most of Mars Year (MY) 36, beginning at Ls=49° and now extend into the aphelion season of MY 37. In this presentation we provide a brief overview of the EMIRS retrievals followed by a description of the seasonal and diurnal variations of the retrieved water vapor column abundance.
Global patterns of tree wood density
Authors: Yang Hui , Benson Vitus , Zhang Yahai , Son Rackhun , Wang Siyuan , Zhang Weijie , Zhang Yuzhen , Robin Claire , Schepaschenko Dmitry , Karaszewski Zbigniew , Krzysztof Sterenczak , Moreno-Martínez Álvaro , Nabais Cristina , Ibanez Thomas , Vieilledent Ghislain , Weber Ulrich , Carvalhais Nuno
Published: February 2023

Wood density is an emergent property resultant of tree growth strategies modulated by local edapho-climatic and stand development conditions. It is associated with the biomechanical support of trees and hydraulic conductivity or safety, directly and indirectly influencing a range of ecological processes, including, among others, tree growth, tree resistance to disturbances, and mortality. Tree wood density is also crucial for assessing vegetation carbon stocks by supporting the link between a volumetric retrieval and a mass estimate. Earlier studies based on tree-level wood density measurements have reported significant relationships between wood density, environmental conditions, and tree growth strategies. However, these were either regionally focused or suffering from data availability, lacking a representative large-scale and spatially explicit representation of factors influencing tree wood density. This study collects and collates information from several sources to construct a global database of 28,822 tree-level wood density measurements alongside with a wide set of climate, soils, topography, and Earth observation covariates to support the development of statistical models for wood density. The dataset, consisting of more than 3,000 global covariates, is used for training different machine learning models, including random forest model (RF), light gradient boosting model (LGBM), extreme gradient boosting model (XGBoost), and bagged trees models. The experimental design considers six cross-validation approaches: either random 5-fold; according to two sets of climate classifications, land cover types, ecozones, or latitudinal ranges. Model performances are assessed with the coefficient of determination (R2) and Root-mean-square errors (RMSE) when predicting an independent test subset of wood density. The top ten models show a prominent performance (R2 > 0.67 and RMSE < 0.09), and their ensemble mean, and standard deviation are considered the best estimation and uncertainty in wood density predictions, respectively. Systematic underestimation biases are observed around the low northern latitudes (0º-20ºN), primarily due to the lack of wood density measurements. Further analysis of sources of uncertainties and their quantification support the generation of a global quantitative and spatially explicit representation of wood density. The ecological interpretation and quantitative assessment of global wood density, and associated uncertainties aim to contribute to improving predictions of vegetation biomass and inferring ecosystem resistance under current and future climate scenarios.
Integration of Seismic and Quasi-Static Signals for Improved Volcanic Monitoring
Authors: Carthy Joe , Vásquez Castillo Alejandra , Titos Manuel , Zuccarello Luciano , Cannovò Flavio , Benitez M. Carmen
Published: February 2023

The time scale of ground displacement at volcanoes varies between short, sub second seismic events, to days, months or even years. This study is focused on data from seismic and GNSS stations located around Mount Etna. The GNSS and seismic stations operate at different time scales. Data from these different time scales is extracted and combined in order to better understand the subsurface dynamics. The overall aim of this research is to improve volcanic forecasting and monitoring. It does this in a novel way by applying signal processing and machine learning techniques to the rich dataset.
Mount Etna offers an interesting case study as it is a widely monitored volcano with a variety of sensors and with a rich pool of data to analyse. Additionally the volcanic dynamics at Mount Etna are complex. This is a volcano where there is a variety of different sub-surface dynamics due to the movement of both deep and shallow magma. This allows for rich insights to be drawn through the combination of different signal types.
This study looks at combining the information obtained from the seismic array at Mount Etna, with the information obtained from various GNSS stations on the volcano. The seismic array has been able to capture ground velocity data in the frequency range 0.025 Hz to 50 Hz from a range of stations at different locations across the volcano. The GNSS stations measure ground displacement with a sampling frequency of 1 Hz, and they allow for longer term ground dynamic analysis.
We analyse different seismic events, and relate the type and number of the seismic events to the long term ground deformation that we see in the recorded GNSS data. Where links between the two signal types have been identified, research is ongoing to establish a direct connection with known volcanic activity on Mount Etna. This will help establish what the relationship that we are seeing signifies. This integration of data from different types of sensors is a significant step into bridging the gap between seismic and quasi-static ground displacement at active volcanoes and should open the path toward more in depth volcanic monitoring and forecasting.
Understanding the impact of agricultural activity in groundwater by water isotopes and dual isotope of dissolved nitrate
Authors: Sanyal Prasanta , Samantaray Santrupta , Mandal Ritwick
Published: February 2023

In general, availability of groundwater have shaped human settlement and land-use patterns by providing water for the people living in an area. However, anthropogenic activities including the agricultural practice impacted the quality and quantity of groundwater significantly. Therefore, it is crucial to monitor and quantify the human impact, and to find pathways towards more sustainable use of groundwater. The Hindon basin in the north-west part of Indo-Gangetic plain in India which once witnessed the Indus valley civilisation, now negatively affected by human influences. The river basin covers an area of ca. 7000 km2 and is inhabited by more than 10 million people. The catchment of the Hindon river hosts sugar mills, paper mills, textile industry and intensified agricultural activities. The land-use pattern data shows that 66% of land is utilised for agriculture including orchards, 15% is used for settlements, 0.5% for industrial purposes, and less than 2% of the basin area has forest cover which is of poor quality. The main crops in the area is sugarcane, and urea is used extensively in the agricultural field. The run-off of nutrients and agrichemicals from the fields deteriorating the water quality, making the Hindon one of the most polluted stretches in the Indo-Gangetic plain.To quantify the impact of agricultural activities in groundwater, water isotopes (δ2H and δ18O) and dual isotopes of dissolved nitrate (δ15N and δ18O) been measured in groundwater. The water isotope data suggest that impact in groundwater is so severe that the canal water, sourced from the glacier melt of the Himalaya, which pass of though the basin is recharging into the groundwater. The dual isotopes of nitrate suggest that the dissolved nitrate which is much above the WHO prescribed limit is mostly sourced from the fertilizer urea. Our result suggests that for sustainability, a multi-crop agricultural practice with less demanding water crop with reduction of use of urea is the need of the hour.
Rapid Detection Of Debris Flows Using Synthetic Aperture Radar: A Coherence-Based Methodology
Authors: Mantovani Matteo , Crema Stefano , Bossi Giulia , Ceccotto Federica , Marcato Gianluca , Pasuto Alessandro
Published: February 2023

The ability to detect and map landslides triggered by intense rainfall in quasi-real time is essential to mitigate their impact and for effective crisis management. The manipulation of space-borne synthetic aperture radar (SAR) images has proven to be one of the most valuable and inalienable asset for this type of investigation. In mountainous areas, morphological variations, related to surface processes and activated by forceful meteorological events, can be usually detected by applying three type of approaches: amplitude-based methods, phase-coherence-based methods and polarimetric techniques. This study present a rapid, effective and straightforward coherence-based methodology which, using just three SAR images, can detect the activation of debris flows with a latency solely related to the repeat cycle of the SAR mission. The technique has been tested in the Italian Dolomites using the dataset of European Space Agency’s mission Sentinel-1, showing promising results. This research is carried out in the framework of Project VAILAND, a joint research agreement funded by the Veneto Region (Italy).