bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of crevasses on surface energy balance at an alpine glacier
Authors: Lin Dongqi , Katurji Marwan , Purdie Heather
Published: February 2023

Observations worldwide have shown that glaciers are receding. Thinning snow cover can result in crevasses becoming exposed at the glacier surface for longer time periods. Crevasses can increase surface roughness, change the surface wind flow fields, and impact the air temperatures within and outside the crevasses (Purdie et al., 2022). Therefore, more can be learnt about regarding the impact of crevasses on energy exchange with glacier atmospheric boundary layer. In order to understand and investigate the atmosphere-crevasse energy exchange, we carried out numerical Large Eddy Simulation (LES) experiments using the PALM model system 6.0 with crevasse-resolving grid spacings less than 1 m. The PALM model system 6.0 has been used for atmosphere and marine boundary layer studies to understand complex processes of atmospheric dynamics and energy balance. Our preliminary results show that the air inside a crevasse does not cool as fast as the air outside a crevasse resulting in net warming from the crevasse relative to the glacier surface. These results agree with the field study conducted at Tasman Glacier (Purdie et al., 2022), and confirm that crevasses could lead to heat storage and increased melting. During the daytime, air temperature inside a crevasse could be 1 °C higher than the air above the glacier surface. After sunset, the presence of the crevasse entrains and traps the warm air such that the centre of the crevasse could still be warmer than the glacier surface during the first half of the evening.  During windy evenings, our results show that turbulent heat exchange associated with eddy entrainment leads to exchange of air mass between the crevasse and the glacier surface, which then causes glacier surface warming. Our preliminary simulations only included one crevasse, while future work will include a field of crevasses to investigate the impact of crevasses in a more realistic environment. This study highlights the importance of including crevasses energy balance in glacier modelling, neglecting which would lead to significant bias in snow melt and mass balance estimations. Reference:Purdie, H., et al. (2022). "Variability in the vertical temperature profile within crevasses at an alpine glacier." Journal of Glaciology: 1-5.
Web Based Tectonic Hazard Monitoring: A case study of 2020 Elazig Earthquake
Authors: Shafapourtehrany Mahyat , vardar Egehan , Havazli Emre , Ozturk Gokalp , Ozener Haluk
Published: February 2023

The 1500km long, EW directional North Anatolian Fault Zone (NAFZ), and the 700km long, SSW directional East Anatolian Fault Zone (EAFZ) are the major geophysical features in Turkey. They are formed where the Eurasian, Anatolian, and Arabian plates meet. Both faults have produced devastating earthquakes (M>6) throughout history and are still actively deforming and threatening populous areas. Even though individual studies focus on the NAFZ and EAFZ, none of them offer a method for continuous monitoring. In this study, we are taking advantage of the Interferometric Synthetic Aperture Radar (InSAR) method and adopting the Small BAseline Subset (SBAS) time series approach to map deformation over large swaths (hundreds of km). We developed a web-based, automated system that takes publicly available Sentinel-1 SAR images and generates deformation maps. We chose the Elazig region as our pilot study area because of the destructive M6.7 earthquake that occurred in January 2020. Our initial results capture the co-seismic deformation coherently and also provide insights into pre-seismic and post-seismic deformation characteristics. Our goal is to provide the scientific community with accurate and easy-to-interpret deformation maps, without needing advanced remote sensing knowledge.
Using Equivalent Horton-Strahler Ratios to Predict Extreme Events in Colombian Andes Catchments
Authors: Bedoya-Soto Juan Mauricio , Ocampo-Zapata Heli Steven
Published: February 2023

The frequency and severity of extreme hydrometeorological events in the Colombian Andes have increased due to the combined effects of climate change and climate variability, with the El Niño-Southern Oscillation (ENSO) being the main contributor. To address this issue and improve hydrologic and hydraulic infrastructure designs, it is necessary to develop better tools for accurately predicting the impact of these events. Hydrological scaling and similarity, based on relatively simple mathematical laws, can synthetically translate the high heterogeneity of hydrological processes into equations that are particularly useful in ungauged catchments, a widespread problem in the Colombian Andes. This research proposes the use of specific hydrological scaling tools, including the Geomorphological Instantaneous Unit Hydrograph (GIUH) and the equivalent Horton-Strahler (H-S) ratios, to calculate peak flows. These ratios express the self-similarity of channels and basins, independent of the threshold area for channel initiation, which the classical bifurcation ratio (RB), length ratio (RL), and area ratio (RA) depend on. Using digital elevation model (DEM) data from NASA's ALOS-PALSAR mission, which provides terrain elevation at a resolution of 12.5m x 12.5m, we analyzed regional patterns of extreme event scaling on various slopes of the Andes Mountains (Colombia) using the GIUH/equivalent H-S theory. With this DEM data, we developed a methodology for automatically extracting the equivalent H-S (RBe, RLe, RAe) in several catchments of the Western, Central, and Eastern ranges that compose the Colombian Andes, while simultaneously validating the self-similarity assumption of their channel networks. Our results highlight the importance of the equivalent H-S ratios as self-similarity indices and regional indicators of the intrinsic relationship between geomorphology and hydrology in the Colombian Andes and their usefulness for hydrological design engineering purposes.
Melt Production beneath subduction zones: Using numerical models to evaluate melt production under batch and fractional melt conditions
Authors: Burkett Francesca , Conder James
Published: February 2023

Melt production at subduction zones depends on numerous variables, including mineral composition, water content, age of the plate, dip angle of the plate subducting, rate of convergence, age of the slab, and forearc dimensions. To evaluate the importance of individual variables and their interaction with each other, we constructed 2D numerical models of subduction, tracking temperature, mantle flow, and melt production. This project examines differences in batch and fractional melting sensitivity to the changes of the different variables. Variables include modal clinopyroxene (cpx) and its exhaustion, mantle hydration, dip angle, convergence rate, and forearc depth. Models tracked total melt as parameters were altered. For this project, the dip angle of the slab varied from 45 to 60°, rate of the slab between 20 and 90 km/Myr, age of the plate between 20 and 90 Myr, forearc depth between 40-50 km, and hydration between 0.01 and 0.1 wt%. The slab age and initial modal cpx levels are held constant throughout all the trials at 60 Myr and 15%, respectively. With batch melting, melting peaks for models set with hydration content > 0.1%, a dip angle at 60°, the highest convergence rates, and the youngest ages. Melting decreases with greater ages and lower convergence rates. In both fractional and batch melting, increasing the hydration leads to an increase in melt production overall. For fractional melting with hydration less than 0.05wt%, the difference in amount of melt compared to batch melting is negligible. At greater initial hydration the difference becomes greater with less produced under fractional melting. Changes in forearc extent also affect total melt with longer forearcs resulting in less melt than shorter ones. Additionally, we explored the effects of permeability on the melt production. Most notably, a secondary region of melt begins to form for when permeability is about 0.02 or greater. The secondary region encompasses melting above the harzburgite solidus. While two melting regions were nearly always observed under batch melt conditions, typically only one region of melting was observed under fractional melt conditions. In both cases, hydration and the dip of subducting slab have the most effect on melt production, while the convergence rate and the depth of the forearc have a smaller effect on melt production.
A bottom-up approach for exploring the role of humidity in high heat-related mortality events: A Multi-City, Multi-Country study
Authors: Sivaraj Sidharth , Lüthi Samuel , Lo Eunice , Vicedo-Cabrera Ana Maria
Published: February 2023

Although studies based on physiological models have repeatedly shown that high humidity levels lead to stronger heat stress in humans, findings from epidemiological studies have remained inconclusive on the matter till date. We aim to employ a ‘bottom-up’ strategy of identifying key drivers of compound events to explore the role played by humidity in high heat-related mortality events, spanning across multiple cities in multiple countries. We used daily data on all-cause mortality, mean temperature and mean relative humidity from 11 cities across the world and applied state-of-the-art epidemiological models to compute the daily observed total mortality counts attributable to heat (i.e., limited to days with average temperature exceeding the ‘temperature of minimum mortality’ (MMT) in each city). Each of these days with mean temperature exceeding MMT is considered as an ’event’ and events with highest mortality counts attributable to heat from multiple cities are analysed in a 2D scatter plot of the corresponding percentile rank of temperature and humidity observed during those events. The frequency of such high impact events in the temperature-humidity percentile space across multiple cities, categorised into sub-groups based on the temperature and humidity climatology of the cities, was then studied. It was observed that close to 90% of the high impact events occurred during high temperature (> 90th percentile) and non-high humid (<50th percentile) conditions. The events of high severity, where humidity conditions were comparatively high (> 50th percentile), were mostly representative of cities with prevailing high humidity conditions on average during the warmest months, when compared across all the cities. Based on our preliminary findings, there is no conclusive evidence that high humidity conditions were prevalent during high heat-mortality impact events, but further analysis incorporating more cities and other climatological variables of interests such as absolute humidity, wet-bulb globe temperature etc. are planned. This novel framework provides valuable insights into the role of humidity in heat stress mortality and can be generalised to address other similar complex research questions in environmental epidemiology.
Modeling population-level controls on soil microbial turnover across scales
Authors: Georgiou Katerina , Guseva Ksenia , Pett-Ridge Jennifer , Kaiser Christina
Published: February 2023

Soil is organizationally complex and spatially heterogeneous with exceptional microbial diversity that varies in time and space. Hotspots of microbial activity are prevalent, yet they are patchy and periodic and it remains intractable to represent this level of detail in macro-scale soil microbial models. Most macro-scale microbial models have, therefore, been focused on exploring theory and capturing select processes in a simplified way. However, effective equations that account for population- and community-level controls may be needed to suitably capture emergent feedbacks at macro-scales. In this study, we explore the effective relationships that emerge between spatially aggregated carbon pools in a micro-scale soil model with competition and space constraints. Specifically, we use an individual-based, spatially explicit model to simulate the response of soil microbes to a range of scenarios with increasing carbon inputs, including spatially-uniform (homogeneous) and spatially-clumped (heterogeneous) increases, where the input flux integrated over the total area is the same in both scenarios. The latter is meant to mimic hotspots of carbon inputs, for example, in the rhizosphere or near preferential flow paths. We find that competition between microbes and the probability of invasion from neighboring microsites plays a critical role in emergent density-dependent dynamics of microbial growth and turnover. Our study elucidates the role of population-level controls on microbial turnover at macro-scales, and motivates careful consideration of scale-dependent model representations. 
Analysis of compound river flood and heavy rainfall events for a development of combined flood maps
Authors: Simon Felix , Mudersbach Christoph
Published: February 2023

Heavy rainfall events and urban flash floods pose a high risk potential for humans and the environment, as a concrete prediction of the regional impacts is difficult. The effects of heavy rainfall events and urban flash floods depend, among other things, on the characteristics of the respective affected area - such as land use, soil type or topographical factors - but also on prior conditions, especially the pre-rainfall index. River floods also pose a similarly high risk, even if they can be predicted more precisely than heavy rainfall events - especially in larger river systems - and thus a more focused flood risk management can be carried out. If these events overlap in the form of compound flooding from river floods and heavy rainfall, the hazards and the risk to people and the environment increase significantly. This was shown in particular by the flood disaster in July 2021 in Rhineland-Palatinate and North Rhine-Westphalia in Germany.Investigations are carried out into the joint occurrence of river floods and heavy rainfall. Discharge data from various stream gauges in North Rhine-Westphalia (Germany) and precipitation data from radar data of the German Weather Service as well as ERA5-Land reanalysis data of the ECMWF are used for this purpose. First, the respective single events are identified and analysed with regard to various statistical parameters. Then the analysis of the compound events is carried out, considering only events that are identical in time and space. To take this into account, simultaneous series are formed from the time series available. Since not all catchments are equally at risk from compound river flood and heavy rainfall events, one focus is on determining vulnerable areas. Here, various characteristic attributes of the catchments but also weather conditions, such as the pre-rainfall index, are considered. It turns out that special attention must be paid to small to medium-sized catchments and to areas with steep and narrow valleys.Furthermore, the joint occurrence probability of river floods and heavy rainfall is determined. This is done with archimedean copula functions. A statement on the joint probability of occurrence of river floods and heavy rainfall has not yet been included in practice or in standards but should be adopted for the correct determination of hazards and risks. Furthermore, based on the analyses carried out, a proposal for the preparation of flood hazard maps by compound river floods and heavy rainfall is presented.
On the atmospheric background for the occurrence of three heat wave types in East China
Authors: Xie Wenxin
Published: February 2023

Compared with daytime (occurring only in daytime) and nighttime (occurring only in nighttime) heat waves (HWs), daytime-nighttime compound HWs (occurring simultaneously in daytime and nighttime) are highlighted to exert much severer impacts especially on human health. However, the physical mechanisms underlying compound HWs are poorly understood. Based on the observed maximum and minimum temperatures and NCEP/ NCAR reanalysis data, this article addressed the physical processes for the occurrence of compound HWs in East China, where compound HWs occur most frequently across China. Comparisons with those related to daytime or nighttime HWs were also performed. The results indicate that the occurrences of three HW types are all associated with anticyclonic circulation anomalies from the upper troposphere to the lower troposphere, whereas their locations and intensities determine the configuration of atmospheric conditions for different categories of HWs. The resultant less (more) cloud cover and humidity as well as increased downward shortwave (longwave) radiation at the surface favor the warming of daytime (nighttime), conducive to the occurrence of daytime (nighttime) HWs. The combination of above conditions associated with daytime and nighttime HWs, which helps the persistence of high temperatures from daytime to nighttime, benefits the occurrence of compound HWs. In addition, nighttime and compound HWs occur with the northwestward extension of the western Pacific subtropical high (WPSH), while it stays in the climatological location for the occurrence of daytime HWs. Further investigation suggests that daytime (nighttime) HWs are accompanied with an upper-tropospheric meridional (zonal) wave train propagating downstream from western Siberia (the east to the Caspian Sea). In comparison, the wave train related to compound HWs shares the mixed features of daytime and nighttime HWs, characterized by a meridional wave propagation from the Scandinavian Peninsula to East China and then a zonal propagation toward the western Pacific.
Regional ecotypes structure biogeography of Amazon forest drought resilience and vulnerability
Authors: Chen Shuli , Stark Scott , Nobre Antonio , Cuartas Luz , Amore Diogo , Restrepo-Coupe Natalia , Smith Marielle , Chitra-Tarak Rutuja , Ko Hongseok , Nelson Bruce , Saleska Scott
Published: February 2023

Amazonia contains the most extensive tropical forests on Earth, but the role of the region as a carbon appears to be declining. Increasing deforestation, fire and climate change-associated increases in drought, threaten to push forests past a tipping point. However, forests are complex, exhibiting drought responses indicative of both resilience (photosynthetic “greening”) and vulnerability (browning and tree mortality) that are difficult to explain by climate variation alone. Still needed is a framework for understanding and predicting how different regions will respond to different kinds of future drought. Here, we combine remotely-sensed photosynthetic vegetation indices (enhanced vegetation index, EVI, corrected for sun-sensor geometry; and solar-induced chlorophyll fluorescence, SIF) with ground-based tree demography to test recent ecological hypotheses about forest drought resilience and vulnerability for different forest ecotypes across the basin, defined by their water-table depth, soil fertility and vegetation characteristics. In high-fertility southern Amazonia, drought response was importantly structured by water-table depth, with resilient greening in shallow-water-table-forests (where greater water availability heightened responsiveness to excess sunlight) contrasting with vulnerability (“browning” and excess tree mortality) over deeper water tables. Notably, shallow-water-table-forest resilience weakened as droughts lengthened. By contrast, low-fertility northern Amazonia, with slower-growing but drought-hardy trees (or tall trees, with deep-rooted water access), supported more drought-resilient forests independent of water-table depth. This work reveals a new biogeography of forest drought response that provides a framework for conservation decisions and improved prediction of heterogeneous forest responses to future climate changes, but warns that longer/more frequent droughts undermine these multiple ecohydrological strategies of Amazon forest resilience.
One year of MLT dynamics over central and northern Peru from SIMONe systems
Authors: Conte Federico , Chau Jorge , Yiğit Erdal , Suclupe José , Kuyeng Karim , Rodríguez Rodolfo
Published: February 2023

One year of Spread spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) measurements are analyzed and compared for the first time between two low-latitude locations in Peru: Jicamarca (12°S, 77°W) and Piura (5°S, 80°W). Investigation of the mean horizontal winds and tides reveals that mesosphere and lower thermosphere (MLT) planetary-scale dynamics are similar between these two locations, although differences can be seen in some tidal components, e.g., the diurnal tide. On the other hand, monthly median values of the 4-hour, 4-km momentum fluxes indicate that the mesoscale dynamics differ significantly between Jicamarca and Piura. These differences are particularly evident during the (southern hemisphere’s) summertime in the zonal component, where a strong acceleration of the background wind by westward-propagating gravity waves (GWs) is observed at all altitudes (80-100 km) only over Piura. The latter finding observationally confirms the previous studies based on model simulations indicating that the directions of the GW drag and the background wind coincide in the low-latitude MLT [Yiğit & Medvedev, 2017].
Relaxation of water-filled blisters via flow through the subglacial drainage system
Authors: Lai Ching-Yao , Stevens Laura , Behn Mark , Das Sarah
Published: February 2023

The drainage efficiency of the subglacial water system evolves during the melt season. However, direct measurement of drainage efficiency under 1000-meters thick ice is challenging. We previously demonstrated that surface observations of rapid lake drainage induced uplifts can be used to assess subglacial transmissivity beneath the ice sheet. When a lake drains, the water reaches the interface between the ice and bed and forms a water-filled blister. This water then drains through the subglacial drainage system. In this study, we use mathematical models to examine the behavior of surface uplift relaxation resulting from different types of drainage systems, including a laminar water sheet, a turbulent water sheet, and a turbulent subglacial channel. Combined with surface GPS observations of five lakes, we showed that the model can be used to study the evolution of subglacial drainage efficiency.
A study on classification and monitoring of marine debris using multi-spectral images and deep learning
Authors: Jeong You Chul , Lee Jong-Seok , Shin Jisun , Jo Young-Heon
Published: February 2023

Marine environmental issues due to marine debris are worldwide phenomena. According to a press release from the Ministry of Oceans and Fisheries of Korea, marine waste collection from the coastal area increased yearly. In 2020, it collected 1.38 million tons, about 45% more than in 2018. To remove them, they were collected and monitored through field monitoring systems. However, it is very inefficient in terms of time and cost. Therefore, the remote sensing approach can be suited for classifying and investigating marine waste dumped in coastal areas. Previous studies have classified marine waste by combining remote sensing based on RGB images and artificial intelligence. However, actual marine waste is often damaged, or its shape is difficult to recognize through RGB images. This study was conducted to classify various wastes using multi-spectral camera and a convolution neural network (CNN) model. We first trained and tested CNN model using three wastes, such as a brown paper box, an orange-colored buoy, and a blue plastic basket with different spectral characteristics in the land environment. Then, we conducted the classification of marine waste using CNN model and multi-spectral images taken with Uncrewed Aerial Systems (UAS) in the marine environment around Socheongcho-Ocean Research Station (S-ORS). The CNN model were trained using 1,452 seawater and 1,319 clear plastic images around the S-ORS with 128 x 128-pixel size. We calculated precision, recall, f1-score, and accuracy, suggesting that the CNN model could be used to classify various marine wastes in the various ocean environment. Overall, these results can provide useful information for marine waste monitoring.
Extreme compositional diversity among rocky exoplanets
Authors: Sossi Paolo , Carmichael Lukas , Hakim Kaustubh
Published: February 2023

To date, more than 5000 exoplanets have been discovered, of which roughly 1800 are thought to be rocky on the basis of mass and radius measurements. However, the resulting densities are degenerate with respect to the compositions of these planets, necessitating other constraints. Of these, the most readily available is the composition of the host star (e.g. Adibekyan et al. 2021). On this basis, the compositions of rocky exoplanetary mantles are expected to be similar to those found in our own Solar System (e.g. Putirka and Rarick, 2019; Spargaaren et al. 2022). Here, we evaluate this conclusion by examining stellar compositions in the system Fe-O-Mg-Si-Ca-Al for F- and G-type stars in the Hypatia and GALAH databases. In reducing the multidimensionality of the dataset, we apply a Principal Component Analysis (PCA) to identify the prevailing chemical trends among the stellar population. We find that the first principal component describes the positive correlation among major element abundances, though O abundance increases less markedly with Fe than those of metals. Therefore, increasing metallicity (as defined by Fe/H) results in an increase in the metal/oxygen ratio of the star. Consequently, the core mass fraction of rocky planets around such stars cannot be treated as a free parameter. Instead, we predict compositions of hypothetical Earth-like planets (i.e., assuming planet/star chemical fractionation equivalent to Earth/Sun) and show that planets around low metallicity stars can be coreless, while those orbiting high metallicity stars should have Fe-free mantles and abundant Si in their cores.
Comparison between empirical and physically-based thresholds for the occurrence of shallow landslides in hillslopes with clayey soils of Northern Italian Apennines
Authors: Bordoni Massimiliano , Pavanello Margherita , Vivaldi Valerio , Meisina Claudia
Published: February 2023

Rainfall thresholds define the conditions leading to the triggering of shallow landslides over wide areas. They can be empirical, which exploit past rainfall data and landslide inventories, or physically-based, which integrate slope physical–hydrological modeling and stability analyses.A comparison between these two types of thresholds was performed in this work, using data acquired in hillslopes characterized by clayey soils of Oltrepò Pavese (Northern Italian Apennines), to evaluate their reliability. Empirical thresholds were reconstructed based on rainfalls and landslides triggering events collected from 2000 to 2018. The same rainfall events were implemented in a physically-based model of a representative test-site susceptible to shallow landslides, considerino different antecedent pore-water pressures, chosen according to the analysis of field hydrological monitoring data.Soil hydrological conditions have a primary role on predisposing or preventing slope failures. In clayey soils of Oltrepò Pavese area, cold and wet months are the most susceptible periods, due to the permanence of saturated or close-to-saturation soil conditions. The lower the pore-water pressure is at the beginning of an event, the higher the amount of rain required to trigger shallow failures is. Physically-based thresholds provide a better reliability in discriminating the events which could or could not trigger slope failures than empirical thresholds. The latter provide a significant number of false positives, due to neglecting the antecedent soil hydrological conditions. These results represent a fundamental basis for the choice of the best thresholds to be implemented in a reliable early warning system.
Magmatic arc compositions governed by climate change: A biogeodynamic perspective from the Eastern Equatorial Pacific
Authors: Errázuriz-Henao Carlos , Gómez-Tuena Arturo , Parolari Mattia , Weber Marion
Published: February 2023

Magmatic arcs modulate global climate over geological timescales through outgassing and rock weathering, but recognizing the fingerprints of climate change in arc magmas remains challenging. Based on a detailed reconstruction of oceanographic, atmospheric, and climatic processes since the middle Miocene, as well as an extensive geochemical database of Miocene and active arc-front magmas from the Trans-Mexican Volcanic Belt, Central American Volcanic Arc, and the North Andean Colombian Arc we developed a conceptual framework by which biogeochemical proxies in oceanic sediments can be tracked down to the composition of arc magmas. Using this framework, we show that the well-documented increases in biologically mediated authigenic Ba and U contents of seafloor sediments from the Eastern Equatorial Pacific (EEP) at the onset of the so-called “carbonate crash” (12–9 Ma) were triggered by an escalation in biological productivity and an augmented efficiency of respiratory carbon storage. We suggest that the temporal modification of the oceanic carbon cycle was regulated by the synchronous formation of three wind-powered seasonal upwellings systems —Tehuantepec, Papagayo, and Panama— that developed in the context of steepening meridional temperature gradients, intensified atmospheric circulation and global climate cooling since the Middle Miocene. Sediments deposited in the context of these newly established upwelling systems became anomalously enriched in authigenic U and Ba not only in comparison to older sediments, but also with respect to geographically adjacent areas of the EEP where vigorous upwellings are absent. These peculiar environmental conditions thus produce a heterogeneous ocean floor that upon subduction and eventual interaction with the mantle wedge creates arc volcanoes with compositional fluctuations that mimic those of the ocean sediments. These findings indicate that the oceanographic and biogeochemical effects of climate change can be engraved on the continental crust and mantle.
AI for Climate Adaptation?
Authors: Neset Tina-Simone , Vrotsou Katerina , Navarra Carlo , Schück Fredrik , Greve Villaro Clara , Mateo Edström Magnus , Rydholm Caroline
Published: February 2023

In October 2021, the Swedish Meteorological and Hydrological Institute launched a novel national system for impact-based weather warnings, moving from the traditional format for meteorological, hydrological, and oceanographic warnings towards an assessment process that includes collaboration and consultation with regional stakeholders on the impacts that certain weather events would have for a specific geographic area and time frame. As part of this new system, local and regional administrative efforts are made to create assessment-support documentation drawing on local knowledge and providing support ahead of and during extreme weather events. We present initial results from the ongoing research project ‘AI4ClimateAdaptation’ (https://liu.se/en/research/ai4climateadaptation), which explores the potential of employing AI-based image and text analysis to support the process and evaluate the precision of impact-based weather warnings. The project collects image and text data appropriate for subsequent use in AI-based analysis from citizen science campaigns and social media. The presentation focuses on the concept of integrating AI-based text and image analysis with the processes of the warning system, as well as the barriers and enablers that are identified by local, regional, and national stakeholders related to the role of AI in weather warning systems. We further discuss to what extent data and knowledge on historical extreme weather events can be integrated with local and regional climate adaptation efforts, and whether these efforts could bridge the divide between long-term adaptation strategies and short-term response measures related to extreme weather events. The results of this study are expected to contribute to the national system for impact-based weather warnings and to increase resilience to extreme climate-related weather events.
Tracking transcription in soil microbial communities during the Birch Effect
Authors: Chuckran Peter , Firestone Mary , Nicolas Alexa M. , Sieradzki Ella T. , Pett-Ridge Jennifer , Blazewicz Stephen
Published: February 2023

In drought affected ecosystems, a large portion of the annually respired CO2 from soil may occur in the short period following the first rain event after drought. This process, where the rewetting of dry soil results in a pulse of CO­2, is commonly known as the Birch Effect. This pulse of activity influences the stability and persistence of soil carbon which, considering the large and growing extent of dryland and drought-impacted ecosystems, may have far reaching implications. It’s been shown that the consumption of the compounds driving the Birch Effect varies temporally and that different taxa grow over the course of wet-up; however, the transcriptional response of specific taxa during wet-up, and their associated characteristics, has not been fully explored.  In this study we map metatranscriptomes against metagenome-assembled genomes (MAGs) in order to assess the transcriptional response of taxa to wet-up at 0, 3, 24, 48, 72, and 168 h post rewetting. We found distinct temporal response patterns that were often conserved on the family-level. Based on response patterns, we grouped genomes into early, mid, and late responders. The average transcriptional profile of MAGs within these different response types did not vary substantially from each other. Instead, for a majority of MAGs, we found shifts in the transcriptional profile of functional genes over time. Together, these findings suggest that much of the temporal dynamics of microbial transcription during the Birch Effect are controlled by differences in within-taxa response time as opposed to stark differences in functional gene transcription between response groups.
From Archaea to the atmosphere: linking above and belowground communities to scale methane and isotopic emissions across the Arctic
Authors: Varner Ruth , Crill Patrick , Kuhn McKenzie , Cronin Dylan , Palace Michael , McCalley Carmody , Burke Sophia , Deng Jia , Saleska Scott , Rich Virginia ,   A2A and EMERGE project teams
Published: February 2023

High latitude peatlands are a significant source of atmospheric methane. Production, consumption and emission rates are spatially and temporally heterogeneous, resulting in a wide range of global estimates for the atmospheric budget of methane. Increasing temperatures in Arctic regions cause degradation of underlying permafrost, changing hydrology, vegetation and microbial communities, but the consequences of this for methane cycling, including stable methane isotopes, are poorly understood. We provide evidence of direct linkages between below ground methanogen communities and above ground plant communities that can be remotely sensed and used in model simulations to effectively predict methane and isotopic fluxes across the landscape. Combining remote sensing with biogeochemical modeling can be used to predict methane dynamics, including the fraction derived from hydrogenotrophic versus acetoclastic microbial methanogenesis. Applying this approach across heterogeneous discontinuous permafrost peatlands enables us to accurately predict isotopic emissions, which will help constrain the global role of Arctic methane emissions.
Unfolding the role of active/break spells in compound hot and dry extremes (CHDE) in India
Authors: Malik Iqura , Mishra Vimal
Published: February 2023

AbstractThe co-occurrence of temperature and precipitation extremes can have profound consequences than either individual extremes. The role of increasing warm spells in increasing CHDEs has been studied in various studies, but the role of active and break spells on CHDEs during monsoon has not been studied. As a result, in this study, we investigated the fraction of CHDEs in both active and break spells in India. We used copula and threshold-based methodology to characterize CHDE to investigate the uncertainty in the frequency of CHDEs during active and break spells. We also looked at how CHDEs in two different spells will impact society differently. We further investigated the changes in CHDEs to future projections of active-break spells of the Indian Summer Monsoon. The findings of the study may help to mitigate the severe impacts of compound hot and dry extremes in the future.Keywords: Climate change, Compound extremes, active spells, dry spells
A near-vertical slab tear in southeastern Solomon Islands
Authors: Cheng Ching-Yu , Ku Chin-Shang , Kuo Yu-Ting , Kuo-Chen Hao , Huang Bor-Shouh , Chen Yue-Gau
Published: February 2023

Mw 6.3 and 6.0 earthquakes occurred on January 27 and 29 in 2020 in the southeastern Solomon Islands which is one of the most seismically active areas in the southern Pacific. To investigate the seismogenic mechanism and structure of the southeastern Solomon Islands, we locate the foreshocks-main-shock-aftershocks sequence of two moderate earthquakes recorded by the regional seismic network. In this study, we establish the new database and locate earthquakes for analyzing the seismogenic structures and deriving the new regional 1D velocity model. Based on the special distribution of the foreshock-aftershock sequence, the interaction of subduction and transform zones between the Pacific and the Australia Plates leads to the near-vertical dip-slip tear structure in the southeastern Solomon Islands. Confirmed with PREM and the new 1D velocity model for testing the robustness of the earthquake locations, the seismic gap at depths from 25 to 35 km is observed as the “jelly sandwich” rheology. In addition, seismic events with large-amplitude, high-frequency signals could be observed in the fore-arc area is due to waves that guided by the subducted Australia plate. In order to improve the capability of earthquake detection, we generate templates from foreshocks-aftershocks sequence to detect repeating or near-repeating seismicity. Our study provides unprecedented seismic data and velocity model for the study area that could benefit understanding detailed structure beneath the region and promoting the initial reference model for locating earthquakes and seismic tomography.
Towards reducing uncertainties of global evapotranspiration due to the energy balance closure gap in flux tower data
Authors: Zhang Weijie , Nelson Jacob A. , Miralles Diego G. , Poyatos Rafeal , Reichstein Markus , Jung Martin
Published: February 2023

Accurate quantification of evapotranspiration (ET) is crucial for understanding variability in the global water cycle, yet state-of-the-art estimates of ET derived from models and remote sensing products contain large uncertainties. Taking the advantage of extensive eddy covariance measurements and machine learning algorithms, ET can be upscaled from globally distributed in-situ observations by combining them with global meteorological and satellite data (e.g., FLUXCOM ensembles, Jung et al., 2019). However, eddy covariance measurements suffer from well-known energy balance non-closure problems, and those uncertainties are further propagated to the global ET estimates. Here, we first estimate the energy balance non-closure within dynamic sliding windows for flux tower site, then we compute correction factors for ET measurements following different hypothesis (that assign errors to latent and/or sensible heat fluxes) according to insights from large eddy simulation studies. Then energy balance closure corrected ET data are used in FLUXCOM to estimate global ET. The upscaled ET then is evaluated by comparison with water-balance-drived ET at the catchment level. This comparison helps to determine the most consistent correction of ET for different regions and conditions. By providing improved global ET estimates, water-related studies can be further facilitated, and model parameterizations can be further optimized to address the challenges posed by climate change on ecosystems and water resources.
Interdependent effects of injection volume and rate on fault slip behavior: A large-scale numerical study
Authors: Mandal Riddhi , Lui Semechah
Published: February 2023

Various injection parameters have been shown to pose significant effects on human-induced seismicity due to a variety of activities such as wastewater injection, carbon storage and geothermal energy production. In this study, we used numerical modeling to investigate how different injection parameters, namely injected volume and injection rate, affect the behavior of faults in the context of fluid-induced seismicity. We tested a large model space (4500 simulations) and modeled injection cases with both spatially homogenous and heterogenous pore-pressure perturbations. Simulation results showed that the two parameters can have various impacts on fault behavior, and that in some cases their effects are interconnected. We discovered that aseismic slip plays a significant role in altering the timing of triggered earthquakes and has lasting impacts on future seismic activity. Moreover, we found that increasing the injection rate tends to increase the size of the triggered cluster of earthquakes, while increasing the injection volume increase the overall rate of earthquakes. We find that spatial heterogeneity has qualitatively similar effects as compared to spatially homogenous cases, with a few quantitative differences. Lastly, we also performed a case study of an injection scenario based on realistic values of pore-pressure diffusion and injection operations in Oklahoma, and we found that for an injection duration of one year, the pore pressure on the faults in the region does not go back to zero even after 70 years and can cause earthquakes years after the end of injection, perturbing the seismic cycles for ~200 years. Our work has potential important implications for safe operation of injection processes which can reduce the risk of seismic hazards.
Analysis Of Glacial Lake And Basinal Topographic Dynamics And Associated Hazards In Brahmaputra Basin, The Water Tower Of India
Authors: Goswami Ajanta , Nahak Tapas , Kumar Shashi Gaurav
Published: February 2023

India has 20 river basins, 12 major and 8 medium and small, with 1869 b.c.m of annual water resource potential. River basins have unequal water resources. Brahmaputra and Barak rivers provide 586 bcm of India's 1869 bcm annual water resource potential (which is roughly 32% of the total potential). These 'Water Tower of India' contains one-third of India's water. Brahmaputra basin, which covers India's NE, has the most water per person. The region has over 13000 cu.m./year per capita, well above Falkenmark's 1700 cu.m. Above the national average of 1544 cu. m.Region has most hydropower potential. Only 3% of the NER's 31,857 MW hydropower potential has been used for human purposes (Brahmaputra Board, 2000), compared to 16% nationally. The NE's hydropower potential is 80% in Arunachal Pradesh (32 percent of the national potential).The Indian government proposed 162 new hydroelectric projects in 16 states, 62 of which are in the Northeast. Most rivers are interstate. This water resource's sustainability is important for population and biodiversity. High-altitude glacial lakes can unleash fury downstream.These Indian water bodies pose many dangers to the region's ethnic tribes. Between 1990 and 2009, climate change increased glacial lake area in the eastern Himalaya. Only China, Nepal, Pakistan, and Bhutan have recorded more than 50 glacial lake outbursts in the HKH.Arunachal Pradesh has 1600 high-altitude lakes. 60 hydropower projects downstream of glacial lakes have been commissioned or proposed.This study maps the glacial lakes of Arunachal Himalaya from the 1980s to the present and examines their dynamism. Morphometric and morphotectonic analysis is used to study the basin's response to flash floods and other hydrometeorological hazards. The interesting results obtained out of glacial lakes dynamics study and the morphometry/morphotectonic analysis of the Brahmaputra basins will be presented in the conference, which is completed new and unreported. 
New Land- vs. Ocean based Global Mean Temperature Reconstructions reveal high consistency except for early 20th Century Ocean Cold Anomaly
Authors: Sippel Sebastian , Meinshausen Nicolai , Fischer Erich , Humphrey Vincent , Rohde Robert A. , de Vries Iris , Knutti Reto
Published: February 2023

Global mean surface air temperature (GSAT) is a key diagnostic for understanding and constraining historical climate variability and change, and for climate policy. Yet, global temperature estimates (1) are usually based on blending sea surface temperatures (SST) with near-surface air temperature over land (LSAT), and (2) contain many missing values due to incomplete coverage in the historical record. While these issues are usually accounted for in model-observation comparisons, elucidating the consistency of LSAT and SST records, and their contribution to GSAT variability and change, remains difficult.Here, we present a set of new GSAT reconstructions based separately on either the historical LSAT or SST record. The method is based on regularized linear regression models trained on climate model simulations to optimally predict GSAT from the climate model’s LSAT or SST patterns, respectively. We then predict GSAT from the HadSST4 and CRUTEM5 observational data, respectively, for each month from January 1850 up to December 2020.We demonstrate that the land- or ocean based GSAT estimates show very similar variability and long-term changes, both in the early (1850-1900) as well as in the late record (post-1950). For example, GSAT of the past decade (2011-2020) increased by 1.15°C (LSAT-based) and 1.17°C (SST-based) relative to an early reference period (1850-1900), which is both well within IPCC AR6 estimates.However, the GSAT estimates show pronounced disagreement in the early 20th century (1900 up to around 1930), when the SST-based GSAT estimates appear on average around 0.3°C colder than the LSAT-based estimates. Decadal changes in the LSAT-based estimates are well explained by the multi-model mean of CMIP6 simulations driven with historical forcings, thus implying only a small role of unforced decadal global variability. In contrast, the SST-based estimate highlights pronounced variability during the early 20th century cold anomaly, which may be related to concerns about instrumental cold biases in SST measurements, but overall reasons for the disagreement remain unclear. Further analysis based on physical reasoning, climate models, and proxy reconstructions, indicates that the ocean data may indeed be implausibly cold.In conclusion, our methodology and results may help to constrain the magnitude of early 20th century warming, and thus to better understand and attribute decadal climate variability.