bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of mineral dust scattering properties simulated by the spheroid and irregular-hexahedral models
Authors: Chang Yuyang , Hu Qiaoyun , Goloub Philippe
Published: February 2023

Monitoring of the vertical structure of airborne mineral dust, the most abundant aerosol species in the atmosphere, is a significant task for lidar measurements. However, due to the complex morphology and large range of particle size, precise modeling of scattering properties of dust aerosol, particularly for the backward direction, is needed to link lidar measurements to particle microphysical properties. In this study, we investigate two scattering models for non-spherical dust aerosol simulation: the Spheroid model (Dubovik et al., 2006) and the Irregular-Hexahedral model (Saito et al., 2021). The Spheroid model characterizes non-spherical particles as a mixture of spheroids, while the latter utilizes an ensemble of 20 irregular hexahedral particles. Previous studies have proved their feasibilities of simulating the scattering properties of coarse non-spherical particles. Nevertheless, there is a lack of direct comparison between the two models, especially the capability of simulating backward lidar measurements.In this regard, firstly, a comprehensive sensitivity study was conducted to compare the sensitivities of particle scattering properties produced respectively by the two models to the change of particle microphysical properties. The particle microphysical properties are characterized by bimodal lognormal size distributions and wavelength independent refractive index (RI) to mimic mineral dust aerosols. Preliminary results show the two models produce same variation tendencies of scattering properties as RI and the fine-mode volume fraction (FVF) change. However, discrepancy between the two models increases with the increase of FVF. Particularly, the spectral depolarization ratio produced by the Irregular-Hexahedral model is evidently larger than that by the Spheroid model. Furthermore, backscattering properties produced by the Irregular-Hexahedral model show larger sensitivity to particle imaginary part of the RI. In the second step, we are going to investigate how these differences influence the retrieval of dust aerosol microphysical properties from the measurements of multi-wavelength Mie-Raman-polarization lidars by incorporating the models into BOREAL (Basic algOrithm for REtrieval of Aerosol with Lidar) (Chang et al., 2022). Scenarios of different types of dust aerosols (pure, polluted, fresh, transported, etc.) will be identified and used for the retrieval and a better understanding of the retrieval differences will be gained based on both specific case studies and statistical analysis.
Quantifying long-term vs short-term uplift and exhumation of the Calabrian Arc - insights into the underlying driving mechanisms
Authors: Villamizar-Escalante Nicolas , Friedrichs Bjarne , von Hagke Christoph
Published: February 2023

Distinguishing the drivers that control mountain building, such as tectonic, climatic, and geodynamic forces of rock uplift at different time scales, forms the basis to understand landscape evolution through time.In this study, we quantify the Cenozoic rock uplift and landscape evolution of the Calabrian Arc, located above the subducting Ionian-oceanic lithosphere in Southern Italy. Here, the Cenozoic rock uplift history has been strongly influenced by the retreat of the Ionian slab southwards, in which the Calabro-Ionian subduction zone shows a roll-back process that has been ongoing since Paleogene times. Some authors have linked rock uplift in the Calabrian arc to (i) tearing of the slab and subsequent toroidal mantle circulation, followed by vertical motion triggered by the detachment of the Ionian slab as a product of elastic rebound, controlling the last exhumation episodes followed by rapid uplift rates in the southern section of the Calabrian arc. (ii) In contrast, others argue that the vertical motion of the slab could also be related to mantle dynamics caused by roll-back inducing mantle upwelling around the Ionian slab edge. (iii) Third, based on thermochronological data, it has been claimed that base-level changes produced by climate change influence the last stage of exhumation. In order to evaluate the possible role of the different driving forces, we present a new compilation of the long-term (low-temperature thermochronology) and short-term uplift and exhumation data (uplift terraces-derived) in combination with new geomorphological data. We focus on three different tectonic blocks (Sila Massif, Serre-Aspromonte Massif and Peloritani Mountains), where the exhumation rates varied from north to south, with the highest long-term exhumation rates to the south (~1 km/Ma). The data is supported by the geomorphological analysis, which agrees with high values of Ksn mean (>250)  in the south and central section but contradicts the surprisingly high Ksn mean values (>250) in the north section. We discuss the landscape history on the long-short term and the possible geodynamic factors that could control the evolution of the Calabrian arc.
Identifying wastewater pollutants from pharmaceutical residues and xenobiotic contaminants in Indian secondary cities
Authors: Kumar Shubham , Tripathi Indra Mani , Mohapatra Pranab Kumar
Published: February 2023

Emerging contaminants are becoming more prevalent in the environment. The consequences of emerging contaminants on the urban environment and living being's health are poorly understood by society. Pharmaceutical compound removal is not considered in designing a conventional sewage treatment facility. Instead, they were primarily concerned with organic and bacterial removal. Molecules containing xenobiotics whose physicochemical characteristics, such as small molecular size, water solubility, ionizability and volatility, make it challenging to identify, quantify, and degrade these complex chemicals. In the present study, we will take samples from Surface Water (SW) and Wastewater Treatment Plants (WTP) in the fast-growing Indian secondary cities (Bhopal, Bhuj and Kozhikode). We use analytical methods, including High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC) coupled with Mass Spectrometry (MS) to identify these compounds. The mentioned techniques have the potential to characterise complex environmental chemicals at low concentrations. In addition, Wetlands Construction can be an alternative and affordable technology for emerging compound treatment that performs satisfactorily for a variety of sewage types, including domestic sewage and wastewater. Our study identifies the contaminants present in the environment and the most popular analytical techniques for identifying and quantifying these compounds. We also present some potential solutions for the treatment of compounds by fusing several other technologies. This shows that in order to lessen or stop the deposition of these compounds into the environment, sewage treatment technologies need to be investigated and combined.
Evaluation of Greenland extreme snow melting patterns and their synoptic drivers
Authors: Bonsoms Josep , Oliva Marc , López-Moreno Juan Ignacio
Published: February 2023

 Greenland Ice Sheet (GrIS) snow melting rates have drastically increased since the 1990s, with relevant implications in the entire ecosystem. According to climate projections, extreme weather events will potentially increase in the coming decades over the GrIS. Thus, it is necessary to analyze the past temporal evolution of GrIS extreme melting patterns, as well as their climate drivers. This work analyzes the GrIS summer extreme snow melting spatiotemporal evolution and trends (1990 to 2021). Further, we determine the contribution of synoptic weather types that drive extreme snow melting events. Results evidence that the frequency, magnitude, and the relative contribution of extreme snow melting to the total summer snow melting differs depending on the GrIS sector. Maximum extreme snow melting days per season are observed in western GrIS, whereas minimums are observed in northern sectors. The average extreme snow melting during summer is non-statistically significant increasing in the entire GrIS, which is consistent with the increase of the average snow melting for the same temporal period. Extreme snow melting days as well as the contribution of extreme snow melting to the total snow melting per season show an upward trend, except in the central and northern zones. The analysis of twenty summer circulation weather types reveals that extreme snow melting episodes for most of the GrIS sectors are mainly explained by a few synoptic systems; characterized by a high-pressure system located in central, southern, and eastern GrIS. During these synoptic episodes, stable weather conditions prevail, and the energy available for snow melting is mainly controlled by positive shortwave radiation heat fluxes leading to positive 850 hPa air temperature anomalies. Results presented in this work are relevant for a better understanding of extreme weather events over GrIS within a changing climate context.
Grapevine agronomic responses to different water regimes south of Tunisia
Authors: ElGhoul Leila , Wassar Fatma , El Mokh Fathia , Nagaz Kamel
Published: February 2023

Water scarcity is a limiting factor for agricultural development. Accordingly, the improvement of its efficiency is indispensable through the application of adequate irrigation strategies including deficit irrigation. In this context this work was undertaken. A field experiment have been carried out in Beni Khdache, south of Tunisia on grapevines to evaluate the agronomic responses, in terms of crop development, yield, yield quality and water productivity, under different water regimes. The first treatment (T100) consisted in delivering to the crop 100% of the ETc. The other two treatments (T75 and T50) consisted in delivering only 75 and 50% of the total real needs of the crop respectively. The fourth treatment (T0) was irrigated according to the farmer's recommendations. The results show a significant effect of the deficit irrigation on the vegetative growth of the grapevines in terms of berry weight. This difference had later a significant impact on the final yield. The highest yield (14t/ha) was found with full irrigation (T100). The farmer's method led to a significant drop in yield (40%) compared to the full irrigation treatment. Trees under water deficit (T75, T50) responded with an accumulation of sugars (17.3 °Brix and 16.8° Brix respectively) and a slight decrease in fruit acidity (3.9 and 3.8 respectively) compared to the T100 treatment (15°Brix,4) .  The difference in irrigation water productivity of the grapevines obtained with the deficit irrigation treatments (T75, T50) is not significant compared to that of T100.  The low water productivity was observed for the T0 and T75 treatments (1.9kg/m3 and 2.4 kg/ m3 respectively), while the highest values were obtained with the T50 and T100 treatments (2.8 kg/m3 and 2.6 kg/m3). These results indicate that full irrigation (T100) seems to be an adequate irrigation strategy for grapevine production under Tunisian arid conditions. Under water scarcity conditions, deficit irrigation with a 25% reduction in inputs (T75) is recommended for grapevine management. The T75 deficit irrigation treatment allows to save large amounts of irrigation water (25%) and to improve water productivity but accepting a certain yield drop.Keywords: Full irrigation, deficit irrigation, grapevine, yield, water productivity, arid environment, farmer's practices
Machine learning-based drivers of present and future inter-annual variability in air-sea CO2 fluxes
Authors: Couespel Damien , Tjiputra Jerry , Johannsen Klaus , Vaittinada Ayar Pradeebane , Jensen Bjørnar
Published: February 2023

The inter-annual variability of the air-sea CO2 flux, is non-negligible, can modulate the global warming signal, yet it is poorly represented in Earth Systems Models (ESMs). ESMs are highly sophisticated and computationally demanding, which makes it challenging to perform dedicated experiments to investigate the key drivers of the CO2 flux variability across different spatial and temporal scales. Machine leaning methods can objectively and systematically explore large datasets, ensuring physically meaningful results. Here, we show that a Kernel Ridge Regression can reconstruct the present and future CO2 flux variability in five ESMs. Surface concentration of dissolved inorganic carbon (DIC) and alkalinity emerge as the critical drivers, but the former is projected to play a lesser role due to decreasing vertical gradient. Our results demonstrate a new approach to efficiently interpret the massive datasets produced by ESMs and at the same time offer guidance into future model development and monitoring strategies to constrain the CO2 flux.
Improving the Balloon-borne Ice Cloud Particle Imager (B-ICI)
Authors: Stenszky János , Kuhn Thomas
Published: February 2023

Atmospheric constituents, such as aerosols and clouds, greatly affect theradiative properties of the atmosphere. Clouds play a substantial role in thisradiative balance. To better understand the contribution of cirrus clouds im-proved modelling and in-situ observations are needed.For further improving current climate-modelling parameters, accurate pa-rameterization of these clouds are required. From in-situ measurements, thesize distribution of cirrus ice particles, their concentration and shape param-eters can be determined. This can be achieved with the iBalloon-borne IceCloud particle Imager (B-ICI). Campaigns done with the B-ICI and resultingparameetrizations have contributed to more accurate characterization of cirrusclouds.The B-ICI is collecting and imaging ice particles with a pixel resolutionof 1,65 µm/pixel. With detailed image analysis at this accuracy particles >20µm can be distinguished, dimensions and concentration can be derived, andparticles can be sorted according to their shape. An improved version of B-ICIis currently being developed. This new version of the instrument is primarilyimproving image quality to enable easier and more automated image processing.Secondarily, changes in the design will reduce the weight of the instrumentand simplify the method for sampling of ice particles. A more light-weightinstrument will allow adding other sensors. In particular, an optical particlecounter to measure aerosol and small ice particles will be added to the B-ICI.This addition of an optical particle counter will result in more accurate sizedistributions in addition of providing complementary aerosol measurements. Inthis paper, we will highlight these changes and improvements in the B-ICI set-up.
Do interactions between litter-feeders and endogeic earthworms impact soil organic matter content and its forms? Results of a microcosm experiment
Authors: D'Hervilly Camille , Frouz Jan
Published: February 2023

Soil saprophagous fauna strongly impacts litter decomposition through its modification of microbial communities and activity. However, soil fauna is very diverse, with different feeding strategies. For example, arthropods such as woodlice and millipedes and epigeic earthworms (litter-feeders) are known to feed on the litter layer, while endogeic earthworms feed on organic particles mixed with the soil mineral layer. Distinct fauna may have a very different impact on the final forms of the soil organic matter. They could act synergistically as endogeic earthworms may require the fragmentation and incorporation of litter into the soil by litter-feeders to access their food. We performed a three-months microcosm experiment in which we tested the effect of litter fragmentation and presence of litter-feeders (isopods or epigeic earthworms of Dendrodrilus rubidus species) on the survival and change in biomass of endogeic earthworms (of Aporrectodea caliginosa species). We also tested whether different combinations of fauna and litter fragmentation affect microbial biomass and respiration, and the forms of the soil organic matter. We used a recent post mining soil, to create a stressful environment with poor food resources for the endogeic species. The hypotheses were that endogeic earthworms would be positively affected by the fragmentation and mixing of litter with the soil, whether it would be done manually or by epigeic earthworms or isopods, and that this would impact soil properties. First results showed no decrease in the biomass of A. caliginosa in any of the treatments. A. caliginosa was able to consume the alder litter added at the soil surface at a similar rate than the epigeic D. rubidus, even without previous fragmentation and in the absence of litter-feeders. A loss of carbon through respiration and an increase of dissolved organic carbon content in the soil were associated with the presence of epigeic earthworms, while an increase in soil microbial biomass carbon was induced only by endogeic earthworms when litter was added at the soil surface. Nitrates content was increased when both types of earthworms were present. Interestingly, endogeic earthworms had an opposite impact on microbial biomass and dissolved organic carbon content when litter was mixed in small pieces with the soil or added at the soil surface. First conclusions are that though the endogeic earthworm A. caliginosa do not seem to require a first fragmentation of the litter to access it, the final effect on decomposition differ according to the other fauna present and to the fragmentation of the litter. Analyses of the forms of the organic matter in the different treatments will allow to determine how this impacted the incorporation of organic matter into the soil.
Forensic Analysis of Urban Flood using Ensemble Hydrologic Modeling
Authors: Peñaloza-Rueda Xóchitl , Centeno-Álvarez Juan Carlos , Courty Laurent G.
Published: February 2023

In the night of 6 to 7 of September 2022, the Tula River in the municipality of Tula de Allende, Mexico, reached its highest level in living memory, flooding the city. More than 31000 peoples were affected and 17 patients at the local hospital died. The Tula river catchment upstream of the city is complex, with four dams, three natural tributaries, and being the outlet of the drainage system of the urban area of Mexico City. Most of those reaches have patchy, inexistent or unreliable hydrometric records, complicating the task of understanding the causes of the flooding.To circumvent those issues related to hydrometric records, in this study we employ an ensemble hydrologic modeling to reproduce the event and shed light on the relative contribution of each tributary to the flood in Tula de Allende. The considered ensemble will comprise ensembles of the catchment parameters and hydrographs coming from the Valley of Mexico. The aim is to obtain an ensemble of hydrographs, from which those that are closest to observed data will be selected, followed by an uncertainty analysis. This methodology is expected to provide reliable hydrological results to be used as an input of a hydrodynamic model to further the analysis of the event.
Chronology of Himalayan valley fills: a key to assessing the fluvial geomorphic response to climate change
Authors: Chauhan Vaishanavi , Mandal Sanjay Kumar , Jaiswal Manoj K
Published: February 2023

Fluvial landforms reflect a balance between tectonics, climate, and their interaction through erosion and sediment deposition. The occurrence of thick valley fills straddling the major Himalayan rivers testify an imbalance between sediment supply and river transport capacity. Whether the aggradation is related to enhanced sediment supply or reduced stream capacity is a matter of debate. The changes in runoff can qualitatively be determined from the paleoclimatic records but the changes in hillslope sediment supply are more difficult to measure and often remain speculative. In-situ produced cosmogenic nuclide inventories in fluvial sediments provide an estimate of catchment-averaged erosion rates. When applied to chronologically-constrained valley fill sediments, this method has the potential to provide paleo-erosion rate and, by implication, sediment discharge from the catchment hillslopes. The paleoerosion rate data in conjunction with the chronology of valley aggradation and paleoclimatic proxy records would allow assessing the impact of monsoon rainfall change on both the hillslope erosion rates and transport capacity of streams. We have applied this approach to the ~90-m thick Beas River valley fills that are exposed near the town of Kullu in Himachal Pradesh, northwestern India. Here, we present preliminary sediment depositional ages determined using the OSL and IRSL methods. Our new luminescence ages suggest that the aggradation of exposed deposits occurred between ̴ 155± 36.99 ka and 58.61± 12.98 ka. These ages when compared with other Himalayan River valleys, indicate a much older and prolonged phase of aggradation. We speculate that the observed discrepancy in depositional ages indicates that either the deposition began significantly earlier in the Beas river valley pointing towards the diachronous valley filling within the Himalaya or the river has incised at a comparably faster rate, resulting in the excavation of older valley fill deposits. We also observed a potential linkage between the terrace formation and monsoon variability where the existing aggradation phase correlates well with the higher rainfall trend when compared with the existing paleoclimate records. The results from our study are in well agreement with already existing depositional age models from other river valleys of Himalayas. 
Organisational preparedness for the physical risks of climate change in the UK
Authors: Dookie Denyse S. , Conway Declan , Dessai Suraje
Published: February 2023

Understanding local perceptions of preparedness, risk and response to climate change is important for effective adaptation-focused actions and policy design. While there have been national surveys of the public’s concern, organisational perspectives are less studied. This research presents findings of a national survey of UK-based organisations’ perceptions about adapting to a changing climate. The survey covers awareness among organisations of climate change, its physical risks and how organisations are taking action to prepare for perceived risks. Administered in spring 2021, our survey summarises the insights of 2,400 respondents in roles related to organisational planning. The majority of respondents (69%) were from the private sector, while others came from public health authorities, local authorities, public educational establishments, and third sector or charitable organisations. 58% of respondents identified the effects of climate change as a concern. While the survey results support a picture of UK organisations taking steps to prepare for similar extreme weather events in the future, action is strongly informed by dealing with the effects of extremes already experienced. There is a much lower proportion of organisations taking measures to deal with the physical risks of future climate change. In terms of future action, organisations perceived a strong role for leadership from government and collective responsibilities for adaptation, signalling a need to recognise this in efforts to promote adaptation. These findings, though UK-centric, provide insight to societal responses, options and pathways, especially at the organisational level for the less widely studied private sector, as noted in IPCC AR6 WGII Chapter 13: Europe. 
A suitable time-dependent conditional probability for Pacific strong earthquakes
Authors: Fidani Cristiano
Published: February 2023

Statistical analyses of NOAA POES data have recently evidenced electron burst losses 1.5-3.5 h before strong earthquakes in the West Pacific and 55-59 h before strong earthquakes in East Pacific. The conditional probability of a strong seismic event after an ionospheric loss event was calculated depicting possible scenarios in both areas. It presented a geohazard risk reduction initiative that can gain valuable preparation time by adopting a probabilistic short-term warning a few hours prior, especially for tsunamis in those dangerous areas. As electron losses were detected in the same region both for West and East Pacific earthquakes, the probability of a strong event in the West Pacific would be first considered and vanish in less than 4 h. Then, after considering the seismic activity, a statistical evaluation of a disastrous event for the East Pacific coast is generated, so defining a time-dependent increase in conditional probability.
A Review on the Water-Energy-Food-Ecosystems Nexus Research in the Mediterranean: Evolution, Gaps and Applications
Authors: Lucca Enrico , El Jeitany Jérôme , Castelli Giulio , Pacetti Tommaso , Bresci Elena , Caporali Enrica
Published: February 2023

Over the last few years, the Water-Energy-Food (WEF) Nexus has been brought forward by scientists as a novel way of analysing the interconnectedness of global resources systems, and by policy makers as an approach to achieving water, food and energy security while preserving the environment.  Implementing such an integrated thinking is crucial for the Mediterranean, a region characterised by increasing demand for food and energy, and vulnerable to water scarcity, impact of climate change and degradation of natural ecosystems.  Through an integrative review of scientific literature, we examined the evolution of Nexus research in the Mediterranean in terms of critical interlinkages being investigated, explored topics, methods and scales of analysis, and context of operationalizations. The 136 reviewed articles revealed that (a) water-energy interlinkages dominates Nexus research in the Mediterranean, driven by the need of satisfying water demands for drinking and irrigation through energy-intensive water resources; (b) the expansion of Nexus thinking to additional components is mostly limited to assessing the impact of Nexus sectors on the physical environment and the climate, without capturing feedback dynamics; (c) there are only few Nexus studies working  at the entire Mediterranean scale which would provide a much needed contextual setting to the impact of isolated case studies; (d) there is promising evidence that Nexus research in the Mediterranean is going beyond the biophysical dimension to encompass socio-economic interactions and governance aspects; yet, (e) their analysis often remain segregated in silos because of a limited integration of methods across disciplines; (f) Sustainable Technology and Natural Resources Management are the key drivers of Nexus research operationalization and would  benefit from an harmonisation to coherently advance Nexus implementation in the Mediterranean region. This review concludes that Nexus research in the Mediterranean would benefit from an integration of the knowledge developed so far in multi-scale, multi-sector, and multi-dimensional frameworks, which would be capable of supporting technological, socio-economic and governance interventions.
On Relationship Between EIT Waves, Solar Winds and CMEs Phenomena
Authors: Verma Virendra
Published: February 2023

In the present paper, we have studied the relationship between the Extreme Ultraviolet Imaging Telescope (EIT) waves phenomena with solar flares, coronal holes, solar winds, and coronal mass ejections (CMEs) events. The EIT/ SOHO instrument recorded 176 EIT events during the above period (March 25, 1997-June 17, 1998) and the EIT waves list was published by Thompson & Myers (2009). After temporal matching of EIT wave events with CMEs phenomena, we find that corresponding to 58 EIT wave events, no CMEs events were recorded and thus we excluded 58 EIT wave events from the present study. Out of 176 EIT wave events, only 106 are accompanied by CMEs phenomena. The correlation study of the speed of EIT wave events and CMEs events of 106  events shows poor correlation r= 0.32, indicating that the EIT waves and CMEs events do not have a common mechanism of origin, and also indicate that some other factor is working in the formation of  CMEs from EIT waves. Further, We have also matched the spatial matching EIT wave sources as indicated by Thomson & Myers (2009) with CHs and flares and found that CMEs appear to be associated with EIT wave phenomena and CHs.  Earlier Verma & Pande (1989), Verma (1998) indicated that the CMEs may have been produced by some mechanism, in which the mass ejected by solar flares or active prominences, gets connected with the open magnetic lines of CHs (source of high-speed solar wind streams) and moves along them to appear as CMEs. Most recently Verma & Mittal (2019)  proposed a  methodology to understand the origin of CMEs through magnetic reconnection of   CHs open magnetic field and solar flares.  In the present paper, we proposed a scenario/ 2-dimensional model, in which the origin of CMEs through reconnection of EIT waves and solar winds coming from the CHs and also found that the calculated CMEs velocity after reconnection of EIT waves and solar winds coming from the CHs are in very close to the observed CMEs linear velocity. We also calculated the value of the correlation coefficient between the observed linear velocity of CME events and the calculated value of CMEs velocity after reconnection and found the value as r=0.884. The value of correlation as r=0.884 is excellent and supports the proposed methodology.  Finally, we have also discussed the relationship of EIT wave phenomena with other solar phenomena, in view of the latest scenario of solar heliophysics phenomena.References:Thompson, B. J. & Myers, D. C. (2009) APJS, 183, 225.Verma, V. K. & Pande, M. C. (1989) Proc. IAU Colloq. 104 Solar and Stellar Flares (Poster Papers), Stanford University, Stanford, USA, p.239.Verma, V. K.(1998) Journal of Geophysical Indian Union, 2, 65.Verma, V. K. & Mittal, N.(2019) Astronomy Letters, 45, 164-176.
Design flood estimation for flood disaster Resilient bridges exposed to climate change
Authors: Kumar Rakesh
Published: February 2023

Flood disaster resilient design of the bridges is the lifeline of the transport infrastructure. Design of flood disaster resilient bridges is the major requirement for construction of the main highways and railway networks as well as for developing the transport networks in hilly regions and remote areas. Inadequate hydrologic and hydraulic design of the bridges results in failure of the bridges and during the current rainy season, a number of bridges were washed away in the India and other parts of the world, mainly due to it. In the present era, the construction technology is in fairly well advanced state and a major challenge associated in construction of the disaster resilient bridge infrastructure is to estimate the accurate design flood and using it for determination of the highest flood level (HFL) of the bridges incorporating the growing climate-change-induced threats of the intensifying extreme weather events. In this research, a procedure for design flood estimation for the bridges will be developed based on the L-moments approach of flood frequency analysis and its superiority will be demonstrated over the existing procedures. The data will be screened using the discordancy measure (Di) in terms of the L-moments. Homogeneity of the region will be tested using the L-moments based heterogeneity measure, H. For computing the heterogeneity measure H, 500 simulations will be  performed using the four parameter Kappa distribution. Comparative regional flood frequency analysis studies ill be performed using the L-moments based frequency distributions: viz. Extreme value, General extreme value, Logistic, Generalized logistic, Normal, Generalized normal, Uniform, Pearson Type-III, Exponential, Generalized Pareto, Kappa, and five parameter Wakeby. Based on the L-moment ratio diagram and Zidist -statistic criteria, the robust distribution will be identified and design flood will be estimated using the robust frequency distribution. Effect of climate change will be studied using the CMIP-5 scenarios and the fixed percentage increases in the design flood. The research will create a climate-resilience-centred procedure leading to policy framework comprising of exhaustive methodology, guidelines and tools for design of flood disaster resilient bridges for the road and railway networks to make the transport infrastructure more resilient in the face of future climate change induced uncertainties of the extreme rainfall events.
Generating self-labeled geological datasets for semantic segmentation using pretrained GANs
Authors: Ferreira Ivan , Koeshidayatullah Ardiansyah
Published: February 2023

Recent advancement in deep generative models (GANs) has brought the attention of many researchers to explore the feasibility of using realistic synthetic data as (i) a digital twin of the original dataset and (ii) a new approach to augment the original dataset. Previous works highlighted that GANs can replicate both esthetical and statistical characteristics of datasets, up to the point of being indistinguishable from real samples, even when being examined by domain experts. In addition, the weights learned during the unsupervised training of these generative models are useful to further extract specific features of interest from the given dataset. In geosciences, many computer vision tasks are related to semantic segmentation, from pore quantification to fossil characterization. In such a task, the labeling process becomes the main limiting point, being both time-consuming and requiring domain experts. Hence, in this study, we repurpose GANs to obtain self-labeled geological datasets for semantic segmentation to be readily applicable in geological machine learning workflows. In this work, we used trained style-based GANs of foraminifera specimens, ooids, and mudstones. Our experiments show that with one or a few labels, we can successfully generate self-labeled and synthetic datasets featuring the labels of interest. This achievement is pivotal in geosciences in exploring the idea of GANs for one-shot and few-shot segmentation and in minimizing the efforts of manual labeling for segmentation requiring domain experts. 
Warm Temperature Anomalies Associated with Snowfall in Antarctica
Authors: Servettaz Aymeric , Agosta Cécile , Kittel Christoph , Orsi Anaïs
Published: February 2023

Antarctica, the coldest and driest continent, is home to the largest ice sheet. A common feature of polar regions is the warming associated with snowfall, as moist oceanic air and cloud cover contribute to increase the surface temperature. Consequently, the ice accumulated onto the ice sheet is deposited under unusually warm conditions. Here we use the polar-oriented atmospheric model MAR to study the statistical difference between average and snowfall-weighted temperatures. Most of Antarctica experiences a warming scaling with snowfall, although with strongest warming at sites with usually low accumulation. Heavier snowfalls in winter contribute to cool the snowfall-weighted temperature, but this effect is overwritten by the warming associated with atmospheric perturbations responsible for snowfall, which particularly contrast with the extremely cold conditions in winter. Disturbance in apparent annual temperature cycle and interannual variability may have major implications for water isotopes, which are deposited with snowfall and commonly used for paleo-temperature reconstructions.
A Geostationary View of a Liquid water Path Adjustment dependence on Cloud Regime
Authors: Smalley Kevin , Lebsock Mathew
Published: February 2023

Aerosol-cloud-interactions remain a large climate uncertainty; especially uncertain is the liquid water path (LWP) adjustment to varying aerosol concentrations in stratocumulus (StCu). Large-eddy simulations (LES) have found that the LWP response of StCu to aerosol can be either positive or negative depending on the cloud regime, whereas climate models simulate uniformly positive correlations. Observations of the real-world evolution of LWP in varying aerosol environments are needed to resolve the nature of the correlation between LWP and aerosol. We address this by analyzing a large ensemble of parcel trajectories over the southeast Pacific within the GOES-16 field of regard. Preliminary results are consistent with LES, showing consistent regime dependent evolution of the LWP depending on the initial cloud state, with LWP generally decreasing with varying number concentrations (N). However, LWP generally increases at low N, potentially supporting LES conclusions showing a cloud-regime dependence. To investigate this further, we will further condition observations by MERRA-2 large-scale environmental variables (e.g. estimated inversion strength, moisture, and boundary-layer decoupling). We expect environmental differences will correlate with the differences between changes in LWP at low and high N.
Analytical framework to model seismic signals from fluid particle collisions in hydrodynamic simulations of glacier melt water
Authors: Turner Ross J. , Magyar Jared , Cook Sue , Reading Anya M.
Published: February 2023

We present an analytic framework to model seismic body waves due to supraglacial, englacial or subglacial flows in solid ice based on a smoothed particle hydrodynamic (SPH) simulation. Consisting of two parts, i) hydrodynamic modelling and ii) seismic wave propagation, the flexible framework allows for a pre-existing fluid simulation to be supplied to generate synthetic seismic signals. The field of glacier-related seismology has seen rapid development in recent years, with an expanded availability of passive seismic datasets that contain records of seismic disturbances generated by glacier processes. Some of these processes, such as basal slip and crevasse propagation, have mechanisms with plate tectonic deformation counterparts, however, many glacier signals are generated by moving melt water. This contribution aims to inform the interpretation of such signals.Our approach tracks the trajectories of fluid particles near the water-ice interface, as recorded in standard simulation outputs, to create a catalogue describing the energetics of each collision. We illustrate the capability of this framework using four end-member cases of water flow along surface channels with different geometries. Seismic signals are simulated at a variety of locations around the channel based on the impulse of the database of simulated collisions. We consider the change in character of the seismic waveforms by modelling frequency-dependent attenuation and weak dispersion in the glacial ice, in addition to the standard geometric spreading. The acceleration time series produced in this work are invariant to the temporal and spatial resolution of the hydrodynamic simulation, provided more than some minimum resolution is used. These time series may be converted to velocity or displacement for comparison with observed seismic signals.Investigating the seismic waves generated for our four channel geometries, we find distinct waveform envelope shapes with different first and later amplitude peaks matching initial and subsequent collisions of the melt water surge with the supraglacial channel walls. The change in waveform character with distance is also captured such that the character attributes due to the process and the those due to the propagation effects may be understood. The flexibility inherent in the model framework will allow for the generation of the seismic signals from simulations of a variety of different water flow geometries including simple 3D channels into and through a glacier. We make the code available as an open source resource for the polar geophysics community with the aim of adding to the toolbox of available approaches to inform the potential future seismic monitoring of melt water movement and related glacier processes.
Causes of the extremely low solar radiation in the 2021 growing season over southeastern Tibetan Plateau and its impact on vegetation growth
Authors: He Yanyi , Yang Kun , Ren Yanghang , Zou Mijun , Yuan Xu , Tang Wenjun
Published: February 2023

The Tibetan Plateau (TP), known as the ‘Third Pole’ region, is one of the most sensitive places to global climate change, which possesses the highest surface incident solar radiation (SSR) in China. In the 2021 growing season, i.e., May to September, southeastern Tibetan Plateau (SETP) registered a widespread and extremely low SSR since 1950 with approximately -18.65 W/m2 of regional mean anomaly relative to 1950-1979 mean. Through the analyses using observations, reanalysis and CMIP6 model simulations, the extremely low SSR event in 2021 is mainly attributed to more clouds and abundant atmospheric moisture caused by anomalous southerlies from the Bay of Bengal. The existence of abnormal south winds could increase the probability ratio of such low SSR events like 2021 to be 9.25 (95% CI: 6.56-19.02). Anthropogenic aerosols and GHGs-induced warming might increase the probability of such SSR events to be a factor of 4.70 (95% CI: 1.66-15.49) and 1.66 (95% CI: 1.01-6.59), respectively. As a result, the extremely low SSR event could significantly reduce local gross primary productivity in the 2021 growing season over SETP, especially in the humid eastern SETP where SSR has a stronger impact on vegetation photosynthesis.
Uncovering the Intrinsic Intensity-Size Relationship of Tropical Cyclones
Authors: Sun Jie , Cai Ming , Liu Guosheng , Yan Ruikai , Zhang Da-Lin
Published: February 2023

The central theme of this study is to explore if and how the intensity of a tropical cyclone (TC) is related to its size. This subject has puzzled atmospheric scientists since the work of Depperman (1947) but the existence of this relationship still remains elusive. The improved understanding of the intensity-size relationship of TCs will help coastal communities to prepare for the maximum potential damage as both the intensity and size have important impacts on wind damages, storm surges, and flooding. This study considers 33 years (1988–2020) of TC records of maximum surface winds and radii of maximum and gale-force winds over the North Atlantic Basin derived from the Extended Best Track Dataset. Analysis of these TC records reveals a robust positive correlation between loss of earth and relative angular momentum. This finding together with the inspiration from the seminal work of Emanuel and his collaborators leads us to combine absolute angular momentum and its frictional loss as a radially invariant quantity, referred to as “effective absolute angular momentum” (eAAM), for radial profiles of TC surface winds. It is demonstrated that the eAAM model can reproduce the observed complex intensity-size relationship of TCs, which can be further reduced to a quasi-linear one after factoring out the angular momentum loss and the radius of maximum surface winds. The findings of this study would not only advance our understanding of the complex TC intensity-size relation, but also allow for operational assessments of TC severity and potential damage just using its outer wind information.
Constraining ocean carbon sink projections in CMIP6 models
Authors: Tjiputra Jerry , Bourgeois Timothée , Goris Nadine , Vaittinada Ayar Pradeebane , Schwinger Jörg , Johannsen Klaus
Published: February 2023

Understanding and limiting the spread of ocean carbon sink projections are crucial to effectively guide the development of climate mitigation policies, determine accurate future carbon budget and subsequently climate change. The North Atlantic and the Southern Ocean are two of the most intense sink regions for anthropogenic CO2 emissions, while the tropical Pacific is the largest outgassing system. Nevertheless, CMIP6 models simulate growing inter-model spread in future carbon fluxes in these regions. In this study, we apply an emergent constraint approach to reduce the projections uncertainties under the high-CO2 future scenario. The efficiency of surface-to-deep transport of anthropogenic carbon is commonly identified as the key mechanisms driving the systematic inter-model spread in high latitude regions. For the North Atlantic region, we further use a genetic algorithm to optimize our identified emergent constraint relationship by isolating the region where contemporary model bias strongly correlates with the projection spread. The interior biogeochemical state is key for constraining the future tropical Pacific CO2 flux. Our study consolidates the importance of improving representations of anthropogenic carbon ventilation mechanisms in models and sustaining carbon and watermass monitoring network in these regions to improve the fidelity of future model projections.
Combining Bayesian Neural Networks with explainable AI techniques for trustworthy probabilistic post-processing
Authors: Clare Mariana , Ben Bouallegue Zied , Chantry Matthew , Leutbecher Martin , Haiden Thomas
Published: February 2023

The large data volumes available in weather forecasting make post-processing an attractive field for applying machine learning. In turn, novel statistical machine learning methods that can be used to generate uncertainty information from a deterministic forecast are of great interest to forecast users, especially given the computational cost of running high resolution ensembles. In this work, we show how one such method, a Bayesian Neural Network (BNN), can be used to post-process a single global high resolution forecast for 2m temperature. This methodology improves both the accuracy of the forecast and adds uncertainty information, by predicting the distribution of the forecast error relative to its own analysis.Here we assess both model and data uncertainty using two different BNN approaches. In the first approach, the BNN’s parameters are defined to be distributions rather than deterministic parameters, thereby generating an ensemble of models that can be used to quantify model uncertainty. In the second approach, the BNN remains deterministic but predicts a distribution rather than a deterministic output thereby quantifying data uncertainty. Our BNN results are benchmarked against simpler statistical methods, as well as statistics from the ECMWF operational ensemble.Finally, in order to add trustworthiness to the BNN predictions, we apply an explainable AI technique (Layerwise Relevance Propagation) so as to understand whether the variables on which the BNN bases its prediction are physically reasonable or whether it is instead learning spurious correlations.
Global warming beyond 1.5–2⁰C multiplies the rainforests' tipping risk
Authors: Singh Chandrakant , van der Ent Ruud , Fetzer Ingo , Wang-Erlandsson Lan
Published: February 2023

Tropical rainforests invest in their root systems to store soil moisture from water-rich periods for use in water-scarce periods. An inadequate root-zone soil moisture storage predisposes or forces these forest ecosystems to transition to a savanna-like state, devoid of their native structure and functions. Yet changes in soil moisture storage and its influence on the rainforest ecosystems under future climate change remain uncertain. Using a mass-balance-based (empirical) understanding of root zone storage capacity, we assess the future state of the rainforests and the forest-savanna transition risk in South America and Africa. For this, we analyse the hydroclimatic estimates of 33 Earth System Models under four different shared socioeconomic pathway scenarios (i.e., SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). We find that by the end of the 21st century, nearly one-third of the total forest area will be influenced by climate change. Furthermore, beyond 1.5-2⁰C warming, ecosystem recovery reduces gradually, whereas the forest-savanna transition risk increases several folds. For Amazon, this risk can grow by about 1.5-6 times compared to its immediate lower warming scenario, whereas for Congo, this risk growth is not substantial (0.7-1.65 times). The insight from this study underscores the urgent need to limit global surface temperatures below the Paris agreement.