bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the influence of urban form on the spatial pattern of precipitation
Authors: Lu Yanle , Li Qi , Yu Zhou , Albertson John , Chen Xiaodong , Chen Haonan , Pendergrass Angeline , Hu Leiqiu
Published: February 2023

Urban areas are known to modify the spatial pattern of precipitation climatology. Existing observational evidence suggests that precipitation can be enhanced downwind of a city, albeit other locations of precipitation enhancement have also been reported. Among the proposed mechanisms that modify the precipitation, the thermodynamic and aerodynamic processes in the urban lower atmosphere interact with the synoptic conditions and could play a key role in determining the resulting spatial variability of precipitation. In addition, these processes are intricately shaped by urban form characteristics, such as the spatial extent of the impervious land. This study aims to unravel how different urban forms impact the spatial organizations of precipitation climatology under different synoptic conditions. We use the Multi-Radar Multi-Sensor (MRMS) quantitative precipitation estimation data products and analyze the hourly precipitation maps for a selected set of cities across the continental United States from the years 2015 to 2021. Results suggest that a statistically significant downwind enhancement of precipitation does exist in about four-fifths of these cities, while the magnitude is comparable to previous findings. Additionally, we find that the precipitation distribution tends to be more clustered for higher wind speed; the location for precipitation maxima is located closer to the city center under low synoptic winds but shifts towards the urban-rural interface under high wind conditions. The magnitude of downwind precipitation enhancement is highly dependent on wind directions and is positively correlated with the city size for the south, southwest, and west directions. This study provides observational proof through a cross-city analysis that the spatial pattern of urban precipitation can be attributed to the modified atmospheric processes by distinct urban forms.
Atmosphere-mediated response of the Southern Hemisphere hydroclimate in simulations of spontaneous Dansgaard-Oeschger-like oscillations
Authors: Trombini Irene , Weitzel Nils , Racky Muriel , Valdes Paul , Rehfeld Kira
Published: February 2023

Dansgaard-Oeschger (DO) events are the most iconic mode of millennial-scale variability during the last glacial period. The manifestation of DO events outside the North Atlantic region and mechanisms responsible for the propagation of the North Atlantic signal across the globe are still little understood. Propagation of DO events to the Southern Hemisphere (SH) has first been explained by oceanic processes, that result in a muted and delayed signal in the Antarctic ice core record, known as Antarctic Isotope Maxima (AIM). Recent ice core-based reconstructions found an additional short-timescale response (years-to-decades, compared to centuries for the oceanic processes) in phase with the climate changes in Greenland. This fast response has been interpreted as the result of atmospheric transport processes. Shifts in the intertropical convergence zone and SH mid-latitude westerlies are seen as mediators of this response.Here, we investigate the propagation of abrupt climate changes in the North Atlantic region to the SH in general circulation model simulations with spontaneous DO-like oscillations under glacial conditions. We study the relative timing of changes in temperature, hydroclimate, and atmospheric circulation and compare our results with ice core and speleothem based reconstructions. In the simulations, the timing of changes in different elements of the climate system varies on a continuum of timescales from months to centuries. This indicates the existence of more complex propagation mechanisms than the simple separation into an atmospheric and an oceanic mode. Our work emphasizes that future analysis of simulations of DO-like events should focus not just on the mechanisms responsible for the spontaneous oscillations but also on the spatio-temporal fingerprint of the oscillations across the globe.
Atmosphere-ionosphere coupling following the Tonga eruption: global multi-scale ionospheric effects
Authors: Zhang Shun-Rong , Aa Ercha , Vierinen Juha , Erickson Phil , Goncharenko Larisa , Coster Anthea , Wang Wenbin , Qian Liying
Published: February 2023

The submarine volcanic eruption at Tonga on 15 January 2022 was a devastated geohazardous rated as VEI (Volcanic Explosivity Index) 5-6, which was the most powerful since the 1883 Krakatoa VEI 6 eruption. The release of enormous amounts of energy into the atmosphere triggered significant geophysical disturbances. In this presentation, we provide various upper atmospheric observations to demonstrate local, regional, and global ionospheric disturbances, including TID global propagation with the most intense, persistent, and consistent wave mode at 300-350 m/s phase speed , EIA deformation and x-cross pattern of EIA crest evolution, equatorial irregularities and bubbles, substantial plasma density depletion. Timing of these and many other observed ionospheric responses was consistent with the Lamb wave arrival, despite of other waves including acoustic and gravity waves as well as tsunami waves were also present in specific regions.  The eruption-excited atmospheric waves produced not only TID global propagation but also modulated the wind dynamos in both E and F regions, driving electrodynamic changes closely associated with EIA and EPBs phenomena at equatorial and low latitudes. These results suggested a new vertical coupling channel through which the intense atmospheric surface disturbance processes can produce far-reaching and long-lasting geospace impacts.
Impact of evaporation in Yangtze River Valley on heat stress in North China
Authors: Bu Lulei , Zuo Zhiyan
Published: February 2023

In North China (NC), heat stress, which can be quantitatively characterized by wet-bulb globe temperature (WBGT), is closely related to specific humidity. This study focuses on the total days for NC averaged daily maximum WBGT exceeding 26°C (WGBT26) per summer (June to August) from 1979 to 2017. Rather than local precipitation or evaporation in NC, the NC WBGT26 is significantly related to the nonlocal evaporation around the Yangtze River Valley (YR). The abnormal positive evaporated water vapor in YR, associated with abnormal water vapor flux from south to north at 925 hPa, is continuously transported to NC in the above-normal WBGT26 years. Such an abnormal “evaporation and transportation” process can significantly increase the water vapor in NC and therefore enhance WBGT26. The evaporation in YR peaks in mid to late July and is closely associated with the occurrence days for daily maximum WBGT exceeding 26°C and maximum daily mean specific humidity at 925 hPa in summer. The main driver for the strongest YR evaporation anomaly from July 15th to August 15th is the simultaneous surface air temperature rather than the simultaneous or earlier soil moisture, precipitation, and vapor pressure deficit (VPD) anomaly. This condition is due to the continuously abundant soil moisture in the YR from April to September. The results of this study provide new ideas for studying heat stress in NC, indicating that nonlocal land-atmosphere interactions are crucial.
Investigating the effectiveness of Nature-Based Solutions (NBS) for climate change adaptation: The case study of Aa of Weerijs catchment, The Netherlands.
Authors: Nazar Irfan , Ali Muhammad Haris , Bertini Claudia , Popescu Ioana , Jonoski Andreja , van Andel Schalk Jan
Published: February 2023

Anthropogenic Climate Change has caused an increase in frequency, intensity and impact of hydro-meteorological-hazards (HMHs) such as floods, droughts, wildfires, and sea level rise. Prior to the 21st century, most policies and strategies to deal with water-related climate risks were based on conventional or grey solutions without considering Nature-Based Solutions (NBS) as potential measures. In the recent past, NBS has gained prominence over conventional measures, in the long run, owing to multi-functionality, flexibility, and cost-effectiveness, providing inter-related and multi-scale benefits to deal with water-related climate hazards.However, the efficiency and robustness of NBS are still under question because of the lack of specialized models and tools to assess them throughout the life cycle and under varying climate patterns. A solid framework of Key Performance Indicators is needed to progress further in promoting NBS at larger scales.In this study, we have explored a set of potential NBS for the Aa of Weerijs catchment, in the Netherlands, which is currently under water stress. The performance of NBS to deal with water-stress-related challenges in the catchment is investigated using a fully distributed physical coupled MIKE SHE-MIKE11 model previously developed. A different set of scales and extents and combinations of NBS have been modelled in the MIKE SHE model of the catchment, ranging from wetlands, detention ponds and river meandering. The performance of NBS is evaluated both for the present and for future climate change conditions, using two sets of climate change projections, the KNMI ’14 scenarios, developed by the Koninklijk Nederlands Meteorologisch Instituut (KNMI), and the RCP 6.0 and RCP 8.5 scenarios, provided by Copernicus.To assess the performance of each NBS set-up and support informed decision-making for stakeholders, a suite of defined KPIs, including surface and groundwater availability in the catchment, water stress ratio, and soil moisture deficit index, is being calculated for each NBS simulation run and used for comparison with base results.The study results are intended to support NBS impact evaluation as an adaptation strategy for the long term.
Automatic Classification of THEMIS All-Sky Images via Self-Supervised Semi-Supervised Learning
Authors: Johnson Jeremiah , Ozturk Dogacan , Connor Hyunju , Hampton Donald , Blandin Matthew , Keesee Amy
Published: February 2023

Dynamic interactions between the solar wind and the magnetosphere give rise to dramatic auroral forms that have been instrumental in the ground-based study of magnetospheric dynamics. The general mechanism of aurora types and their large-scale patterns are well-known, but the morphology of small- to meso-scale auroral forms observed in all-sky imagers and their relation to magnetospheric dynamics  and the coupling of the magnetosphere to the upper atmosphere remain in question. Machine learning has the potential to provide answers to these questions, but most existing auroral image data lack the ground-truth labels required for supervised learning and conventional statistical analyses. To mitigate this issue, we propose a novel self-supervised semi-supervised algorithm to automatically label the THEMIS all-sky image database. Specifically, we adapt the self-supervised Simple framework for Contrastive Learning of Representations (SimCLR) algorithm to learn latent representations of THEMIS all-sky images. These representations are finetuned using a small set of manually labeled data from the Oslo Aurora THEMIS (OATH) dataset, after which semi-supervised classification is used to train a classifier, beginning by training on the manually labeled OATH dataset and gradually incorporating the classifier’s most confident predictions on unlabeled data into the training dataset as ground-truth. We demonstrate that (a) classifiers fit to the learned representations of the manually labeled images achieve state–of–the–art performance, improving the classification accuracy by almost 10% over the current benchmark on labeled data; and (b) our model’s learned representations naturally cluster into more clusters than manually assigned categories, suggesting that existing categorizations are coarse and may obscure important connections between auroral types and their drivers. Finally, we introduce AuroraClick, a citizen science project with the goal of manually annotating a large representative sample of THEMIS all-sky images for the validation of our current models and the training of future models.  
Thermodynamic integration via Replica Exchange Hamiltonian Monte Carlo for faster sampling and model comparison
Authors: M. Ndiwago Damian , Nijzink Remko , Ley Christophe , J. Schymanski Stanislaus , S. Hale Jack
Published: February 2023

Hydrologists often need to choose between competing hypotheses or weight the predictions of different models when averaging models. Several criteria for choosing and weighting models have been developed, which balance model complexity and goodness of fit by penalising the number of model parameters. The penalty is explicit for information theory approaches or implicit for Bayesian model selection based on marginal likelihood and, by extension, the Bayes factor. The Bayes factor is the ratio of the marginal likelihoods of two competing models. Also, the Bayes factor can be used for non-nested models in contrast to information-theoretic approaches. However, marginal likelihood estimation is computationally intensive and slow for dynamic models with multiple modes. This study uses Replica Exchange Hamiltonian Monte Carlo and thermodynamic integration for fast, simultaneous calculation of marginal likelihood and parameter identification of dynamic rainfall-runoff models. Using synthetic data, the method selected the true model in our numerical experiments. The technique was also applied to real data from Magela Creek in Australia. The selected model was not the model with the highest or lowest number of parameters for real data. The method is implemented using the differentiable programming software ''TensorFlow Probability". This implementation can be applied to other types of models for fast simultaneous parameter estimation and model comparison.
Microstructural controls on seismicity distribution in simulated fault gouges
Authors: Niemeijer Andre R. , Korkolis Evangelos , Mishra Tanmaya , Elbertsen Rens , Jop Beunen , Pires de Vasconselos Ivan
Published: February 2023

In order to make seismic hazard estimates, it is necessary to assume some distribution of the number of earthquakes of a certain magnitude, i.e. a Gutenberg-Richter distribution. This is true for both natural seismicity as well as induced seismicity, but in both cases the number of historical earthquakes at the tail end of the distribution (i.e. the largest ones) is limited and often the maximum possible magnitude is unknown. In contrast, in a laboratory setting the maximum size of an unstable slip event (“stick-slip” or laboratory earthquake) is controlled by the size of the sample and the imposed stress. In our rotary shear apparatus, we can theoretically achieve unlimited fault displacement which allows us to produce earthquake-like distributions with thousands to tens of thousands event.In this presentation, I will present results from experiments on simulated fault gouges which show unstable frictional behaviour at room temperature conditions. The results show that the event size distribution can change spontaneously, without any changes in the boundary conditions. Observations of fault gouge material after the experiment, suggest that wear of the granular material generates alternative surfaces for slip, which changes the macroscopic behaviour. Interestingly, the change in event size distribution is reversable, presumably because the fine-grained layers become disturbed with ongoing shear. In an attempt to simulate the macroscopic behaviour, we have, for the first time, measured the rate-and-state frictional (RSF) properties on single grain contacts. Using these values in a numerical model for seismic slip (so-called “seismic cycle simulator”), we obtain maximum stress drops that are comparable to those obtained in the experiments, but with some differences. The differences are most likely due to the fact that the grains in our simulated fault are affected wear in previous slip events, which should change their RSF parameters. In addition, the normal stress at each individual grain contact is unknown in the experiment and could vary significantly from event to event.  This latter difference between model and experiment can be overcome by using a discrete element method with contact-scale RSF properties to simulate slip.
Foundational women in planetary geomorphology: Some contributions in fluvial, aeolian, and (cryo)volcanic subdisciplines
Authors: Burr Devon , Diniega Serina , Quick Lynnae , Gardner-Vandy Kathryn , Rivera-Hernandez Frances
Published: February 2023

As detailed in a recent journal publication by the authors of this abstract, women have made significant contributions in the fluvial, aeolian, and (cryo)volcanic subdisciplines of planetary geomorphology, despite undeserved challenges to their participation. Some women—in particular, women of color—are highlighted in this work to show a part of these foundational contributions. As the latter half of the 20th century was a revolutionary time for terrestrial geomorphology and the inception of the discipline of planetary geomorphology, we focused our research into these contributions on women scientists who were working during this time. We also focused on women working in our scientific subdisciplines so that we could provide proper context for their work. These contributions have occurred both as discoveries in terrestrial geomorphology leading to follow-on discoveries in planetary geomorphology and through serving as educators and role models. With women increasingly achieving positions of influence both in the geo- and planetary sciences as in American society, this research allows us to celebrate these contributions of women and particularly women of color while looking forward to a more complete record of their past contributions and greater future achievements.
A Simple yet Correct Theory for the Formation of Magnetic Switchbacks Observed by Parker Solar Probe
Authors: Toth Gabor
Published: February 2023

Magnetic switchbacks are rapid high amplitude reversals of the radialmagnetic field in the solar wind that do not involve a heliosphericcurrent sheet crossing. First seen sporadically in the seventies inMariner and Helios data, switchbacks were later observed by theUlysses spacecraft beyond 1 au and have been recently identified as atypical component of solar wind fluctuations in the inner heliosphereby the Parker Solar Probe spacecraft. We provide a simple yetpredictive theory for the formation of these magnetic reversals: theswitchbacks are produced by the shear of circularly polarized Alfvenwaves by a transversely varying radial wave propagation velocity.  Thewave speed can be modulated by variations in bulk velocity, radialmagnetic field, density or any combination of these.  We provide ananalytic expression for the magnetic field variation as a function ofthe wave velocity shear, establish the necessary and sufficientconditions for the formation of switchbacks and show that themechanism works in a realistic solar wind scenario. The suggestedmechanism is in full agreement with Parker Solar Probe observations,including the shape of the switchbacks, the correlations of thecomponents of the magnetic field, and the dependence of variousquantities on radial distance.  We show conclusively that this is thefundamental process that creates switchbacks.
Mechanochemical Destruction of Per-and Polyfluoroalkyl Substances in four Aqueous Film Forming Foam Formulations using amended Silica Sand and Potassium Hydroxide
Authors: Turner Lauren P. , Patch David J. , Kueper Bernard H. , Weber Kela P.
Published: February 2023

Per- and polyfluoroalkyl substances (PFAS) are a diverse group of manmade, fluorinated organic chemicals that gained notoriety for their diverse application, widespread distribution in the environment and toxicity. One of the main sources of PFAS to the environment is through aqueous film forming foam (AFFF), intended for use on fuel fires. AFFF may enter the environment through system testing, training activities, emergency use or accidental release. When AFFF enters the environment PFAS readily adsorb to porous media through hydrophobic and electrostatic interactions. As a result, PFAS impacted porous media may act as a long-term source of contamination to groundwater, potentially influencing water resources and human health. There is a demand for effective treatment of PFAS impacted porous media. Ball milling has emerged as a potential treatment option for PFAS, however, the viability of treating AFFF impacted porous media has been seldom explored. In this work four AFFF formulations were amended onto silica sand and milled without and with the use of potassium hydroxide (KOH) as a co-milling reagent. Six hour milling trials were conducted using a planetary ball mill with stainless steel grinding media. Significant destruction of perfluorosulfonic acids, perfluorocarboxylic acids (PFCAs), fluorotelomer sulfonates, fluorotelomer betaines and fluorotelomer sulfonamido betaines was observed. With the use of KOH as a co-milling reagent the total PFAS destruction percentage in all four AFFFs exceeded 90%. Greater destruction of PFAS was observed in fluorotelomer dominant AFFFs when compared to perfluoroalkyl acid dominant AFFFs. PFCAs and soluble fluoride were identified as destruction byproducts. KOH as a co-milling reagent had the effect of reducing PFCA byproduct formation and increasing fluoride recovery in three of four AFFFs. Fluoride recoveries indicate PFAS molecule defluorination occurs by ball milling. When PFAS in AFFF is compared to PFAS destruction in single analyte trials, less destruction is observed, displaying the necessity of evaluating realistic AFFF contamination events over single or multi analyte mixtures.
New data on the geology and characteristics of erionite in New Zealand
Authors: Patel Janki P. , Brook Martin , Gualtieri Alessandro F. , Kah Melanie , Hamilton Ayrton
Published: February 2023

Erionite is a naturally occurring zeolite originating from hydrothermal alteration or diagenesis of volcanic rocks. Typically, the two main types of rock in which erionite occurs are basalt and tuff. Erionite generally displays a fibrous morphology, and as with asbestos fibre exposure, respirable fibrous erionite has been linked to cases of malignant mesothelioma. Notably, fibrous erionite appears to be comparable or even more carcinogenic than the six regulated asbestos minerals. The first health issues regarding erionite exposure were observed in Cappadocia (Turkey), and more recently, occupational exposure issues have emerged in the USA. The International Agency for Research on Cancer (IARC) has classified erionite as a Group 1 carcinogen. Nevertheless, undisturbed erionite fibres are not thought to pose a risk to human health. In New Zealand, erionite has been found in surface rock exposures at numerous locations throughout both the North and South Islands, including (from north to south) Kaipara, Auckland, Taupo Volcanic Zone, Banks Peninsula, and the Moeraki coast. Due to the carcinogenic nature of erionite, understanding the distribution and character of the mineral fibres in New Zealand is pivotal. This investigation into erionite in New Zealand is being undertaken using optical and electron microscopy, X-ray powder diffraction and Raman spectroscopy to identify erionite and other zeolites occurring alongside the mineral. Notable examples identified so far include woolly erionite in vesicles within rhyolitic rock in the Canterbury region of the South Island, and asbestiform erionite in the Waitakere Group Volcanics in the Auckland region, of the North Island. Further research is currently ongoing to further delineate the geological occurrence and characterise the mineralogy and chemistry of all erionite samples from New Zealand in an attempt to outline the crystal chemistry of erionite from New Zealand and the related environmental risk hazards.
Mycorrhizal fungi alleviate acidification-induced phosphorus limitation: Evidence from a decade-long field experiment of simulated acid deposition in a tropical forest in south China
Authors: Hu Yuanliu , Chen Ji , Deng Qi
Published: February 2023

Tropical forests in southern China have been suffering high level of acid rain in recent decades, which may alter soil phosphorus (P) supply capacity and thus affect ecosystem productivity. We conducted a 10-yr field experiment of simulated acid rain (SAR) to examine how acidification impacts seasonal changes of soil P fractions in a tropical forest with highly-acidic soils in south China. The results showed that SAR significantly reduced soil P bioavailability, with increased occluded P pool but reduced the other more labile P pools in the dry season. The decreased soil P bioavailability was primarily related to the repressed P desorption capacity and enhanced P sorption during soil acidification, which regulated by acid-activated soil iron/aluminum minerals and soil organic matter. However, in the wet season, SAR did not change microbial P, soluble P and labile organic P pools. Different from the decline of microbial abundance in the dry season, SAR increased ectomycorrhizal fungi and its ratio to arbuscular mycorrhiza fungi in the wet season, which significantly stimulated phosphomonoesterase activities and likely promoted the dissolution of occluded P. Our results suggest that, even in already highly-acidic soils, the acidification-induced P limitation could be alleviated by stimulating ectomycorrhizal fungi and phosphomonoesterase activities. The differential responses and microbial controls of seasonal soil P transformation revealed here should be implemented into ecosystem biogeochemical model for predicting plant productivity under future acid deposition scenarios.
Effect of snow-to-rain transition on precipitation partitioning in a mountainous catchment: insights from geophysics-informed hydrologic modeling
Authors: Chen Hang , Niu Qifei
Published: February 2023

In snow-dominated regions, snowmelt water plays a critical role in recharging the subsurface and generating streamflow. With a changing climate, the fraction of annual precipitation that falls as snow will probably decline. Rainfall and snowmelt water have different interactions with the subsurface and potentially vegetation, thus affecting the partitioning of precipitation into subsurface storage and streamflow. Currently, our understanding of how snow-to-rain transition affects this hydrologic partitioning in mountainous catchments is still limited. To take the best management practices for climate change adaptation, it is of critical importance to study how a catchment responds to such environmental disturbances.In this study, we use the geophysics-informed hydrologic modeling to study the effect of snow-to-rain transition on hydrologic partitioning in a snow-dominated mountainous catchment in Idaho, USA. In the modeling, the subsurface structure was extracted from velocity map obtained from seismic refraction tests. Many studies has highlighted the importance of the heterogeneous subsurface in water partitioning in catchments, but accurate characterizations with traditional field techniques such as drilling are challenging. The hydrologic model developed from geophysical results is then calibrated with historical hydrometeorological measurements. Two climate change scenarios are designed to study the impact of warming on streamflow generation and water storage. In Scenario 1, a uniform warming is considered throughout the year, and an air temperature increase (+2.5 °C) is applied to change the phase of precipitation. In scenario 2, warming is only applied to the snow season (i.e., from December to April). The numerical modeling results show that a uniform warming (scenario 1) significantly promotes evapotranspiration (ET), and streamflow becomes less productive. Warming in the snow season only (scenario 2) induces an earlier, flashier streamflow but the partitioning of precipitation between storage and streamflow is not significantly changed. Compared to simulation results from traditional hydrologic modeling (without the heterogeneous deep subsurface), geophysics-informed hydrologic modeling reveals the importance of water storage in the fractured bedrock in response to the climate change.
Quantifying the Channel Networks of Fan-Shaped Landforms on Mars
Authors: Gezovich Luke , Plink-Bjorklund Piret , Henry Jack
Published: February 2023

            River deltas and fluvial fans are both fan-shaped landforms that contain complex channel networks. Fan shaped landforms have also been identified on Mars at Jezero, Eberswalde, and Gale craters among many other locations. A principal distinction between these two landforms is that only deltas systematically form along the shorelines of a standing body of water. Fluvial fans may form along a body of water, but can also form hundreds of kilometers inland. It is thus crucial to be able to accurately distinguish between deltas and fluvial fans for the purposes of mapping paleo-shorelines on planetary bodies and understanding paleoclimates. In this work, we apply multiple quantitative methods on Martian fan-shaped landform channel networks to map channel networks to differentiate fluvial fans from river deltas on Mars. We quantify differences in channel bifurcation and divergence angles due to channel crossovers. We also measure changes in channel reach length between bifurcation and divergence nodes. Differences in channel networks occur because fluvial fans are built by channel bed aggradation and channel avulsion. River deltas are constructed by both mouth bar growth and consequent channel bifurcations, as well as infrequent avulsions. In river deltas on Earth, channel bifurcations form at an angle of approximately 72°. Channel lengths and widths in river deltas decrease downstream with increases in successive channel bifurcations. On the contrary, fluvial fan avulsions generate smaller divergence angles and down-fan channel narrowing is not necessarily linked to divergence nodes. This project applies Earth derived channel network mapping techniques to Martian fan-shaped landforms and demonstrates that this methodology is applicable on Mars. Preliminary analysis of the channel network of the Jezero crater landform suggests that it resembles a fluvial fan and not a delta. Conversely, preliminary analysis of the Eberswalde crater channel network suggests that the landform here does resemble an Earth river delta. Our results indicate that fan-shaped channel networks can and must be carefully assessed. This is especially true if the presence of deltas is used for the estimation of the location of paleo-shorelines on planetary bodies, as only deltas regularly form at shorelines. Alternatively, additional evidence is required to identify paleo-shorelines as fluvial fans may also form along shorelines. On Earth, fluvial fans are less sensitive to sea-level rise and coastal hazards than deltas and thus react differently from deltas due to changing sea levels.
Novel methods for determining the 14C age of microbially assimilated soil carbon
Authors: Finstad Kari , Nuccio Erin , Grant Katherine , Pett-Ridge Jennifer , McFarlane Karis
Published: February 2023

Soils are a significant component of the Earth’s carbon (C) cycle, yet a mechanistic understanding of what controls the turnover of this large C pool remains elusive. Microbial respiration of organic C accounts for roughly half of the total CO2 production from soils, though limited options exist for accurately identifying the source of C assimilated by microbial communities. Currently, radiocarbon (14C) analysis of evolved CO2 from soil incubations is the most common laboratory method for this, however they can introduce artifacts due to sample disruption and processing and can take months to produce sufficient CO2 for analysis. We present novel extraction methods which allow for the direct 14C analysis of microbial biomolecules and compare the results to laboratory incubations. Preliminary results suggest that in the upper 50 cm soil depths, the Δ14C from incubations is indistinguishable from that of extracted microbial biomass. Below 50 cm, the Δ14C of the microbial biomass is more depleted than that of the incubations, either due to the stimulation of labile C decomposition in the incubations, or the inclusion of biomolecules from non-living cells in the biomass extractions. Work is ongoing to identify the source of the extracted biomass pool and additional methods for isolating specific, short-lived biomolecules such as RNA, are underway to unambiguously determine the Δ14C of organic molecules being assimilated by active microbial communities.
Foundation AI Models for Science
Authors: Maskey Manil , Ramachandran Rahul , Lee Tsengdar , Ganti Raghu
Published: February 2023

Foundation Models (FM) are AI models that are designed to replace a task or an application specific model. These FM can be applied to many different downstream applications. These FM are trained using self supervised techniques and can be built on any type of sequence data. The use of self supervised learning removes the hurdle for developing a large labeled dataset for training. Most FM use transformer architecture utilizes the notion of self attention which allows the network to model the influence of distant data points to each other both in space and time. The FM models exhibit emergent properties that are induced from the data. FM can be an important tool for science. The scale of these models results in better performance for different downstream applications and these applications show better accuracy over models built from scratch. FM drastically reduces the cost of entry to build different downstream applications both in time and effort. FM for selected science datasets such as optical satellite data, can accelerate applications ranging from data quality monitoring, feature detection and prediction. FM can make it easier to infuse AI into scientific research by removing the training data bottleneck and increasing the use of science data.
­­Carbon Costs of Plant Nutrient Acquisition Improve Present-Day Carbon Cycle Estimates and Limit CO2 Fertilization Effect
Authors: Braghiere Renato K. , Fisher Joshua , Allen Kara , Brzostek Edward , Shi Mingie , Yang Xiaojuan , Ricciuto Daniel , Fisher Rosie , Zhu Qing , Phillips Richard , Sulman Benjamin , Steidinger Brian , Soudzilovskaia Nadejda , Liang Jing , Peay Kabir , Crowther Thomas
Published: February 2023

Most Earth system models (ESMs) do not explicitly represent the carbon (C) costs of plant nutrient acquisition, which leads to uncertainty in predictions of the current and future constraints to the land C sink. While plants acquire nutrients through different uptake pathways, such as from mycorrhizae, direct root uptake, retranslocation from senescing tissues, and biological fixation in the case of nitrogen (N), they usually have different associated C costs. Determining the amount of nutrients acquired through each uptake pathway and the associated C cost could increase understanding of the global C and nutrient cycles, as well as the predictive skills of ESMs.Here, we integrate a plant productivity-optimizing nutrient (N and phosphorus (P)) acquisition model (Fixation & Uptake of Nutrients, FUN) into the Energy Exascale Earth System (E3SM) Land Model (ELM) to simulate the global C and nutrient cycles (Braghiere et al., 2022). We benchmarked the model with observations (in-situ, remotely sensed, and integrated using artificial intelligence), and other ESMs from CMIP6; we found significant improvements in present C cycle variables estimates. We also examine the impact of mycorrhizal spatial distributions on the global C cycle, since most plant species predominantly associate with a single type of mycorrhizal fungi and uncertainties in mycorrhizal distributions are non-trivial, with current estimates disagreeing in up to 50% over 40% of the land area (Braghiere et al., 2021). Global Net Primary Productivity (NPP) is reduced by 20% with N costs and 50% with NP costs, while modeled and observed nutrient limitation agreement increases when N and P are considered together. Even though NPP has been growing globally in response to increasing CO2, as soil nutrient progressively becomes more limiting, the costs to NPP for nutrient acquisition have increased at a faster rate. This suggests that nutrient acquisition will increasingly demand a higher portion of assimilated C to support the same productivity.Braghiere, et al. (2022) doi.org/10.1029/2022MS003204Braghiere, et al. (2021) doi.org/10.1029/2021GL094514
Evaluation of continental-scale ensemble hydrological forecasts from Environment and Climate Change Canada: a comparison with forecasts from the Global Flood Awareness System (GloFAS)
Authors: Fortin Vincent , Innocenti Silvia , Gaborit Étienne , Durnford Dorothy , Keita Setigui , Bruxer Jacob , Boucher Marie-Amélie , Harrigan Shaun , Zsoter Ervin , Dimitrijevic Milena , Sévigny Caroline , O'Brien Nicole , Gervasi Natalie
Published: February 2023

Environment and Climate Change Canada (ECCC) is in the process of deploying a continental-scale hydrological prediction system known as the National Surface and River Prediction System (NSRPS). Operating at a resolution of 30 arc seconds, NSRPS currently generates Ensemble Streamflow Predictions (ESPs) for over four million grid points. Issued once per day, the ensemble is composed of twenty members and provides 16-day forecasts. NSRPS differs from other hydrological forecasting systems in operational use in Canada by being continental in scope and by relying on an Earth System Modelling (ESM) approach for prediction. In order to assess the value of forecasts issued by NSRPS, a comparison is performed with a similar ESP system available over all of Canada: the Global Flood Awareness System (GloFAS) from the European Centre for Medium-Range Weather Forecasts (ECMWF). The evaluation focusses on the Great Lakes and St. Lawrence watershed as well as the Nelson and Churchill watersheds, each over one million km² in size. 393 streamflow stations are identified where NSRPS and GloFAS agree on the watershed delineation. The comparison is limited to the Spring, Summer and Fall of 2022 due to NSRPS forecast data availability. For most stations, NSRPS performs better than GloFAS in terms of Continuous Ranked Probability Score (CRPS), but the median of the potential CRPS across the 393 stations is very similar for days 3-16. Both systems suffer from a lack of spread, particularly for short lead times, but the problem is slightly more acute for GloFAS. Bayesian Model Averaging (BMA) is explored in order to obtain calibrated probabilistic forecasts that perform better than both NSRPS and GloFAS. 
Introduction to GEMS version two air pollutants retrieval algorithm
Authors: Hong Hyunkee , Park Junsung , Lee Hanlim , Lee Wonjin , Kim deokrae , Kim Jhoon , Lee Dongwon
Published: February 2023

Geostationary Environment Monitoring Spectrometer (GEMS), the world's first geostationary environmental senor onboard Geo-Kompsat 2B, was launched in February, 2020 to monitor atmospheric pollutants (such as -> e.g. Aerosol properties, Nitrogen dioxide, Sulphur dioxide, Formaldehyde and Ozone) with high temporal and spatial resolution over ASIA. Environmental Satellite Center (ESC) of National Institute of Environmental Research has distributed these data since March, 2021 after in-orbit test was completed. We performed the accuracy validation of GEMS atmospheric pollutants retrieval algorithm using other environmental satellite (such as TROPOMI, OMPS, etc.) and ground-based measurements (such as Pandora, Max-DOAS, etc.) data through GEMS Map of Air Pollution (GMAP) and Satellite Integrated Joint monitoring of Air Quality (SIJAQ) campaign. We validated the accuracy of GEMS atmospheric-pollutants-retrieval algorithm using the data from other environmental satellites (e.g. TROPOMI, OMPS, etc.) and ground-based measurements data (e.g. Pandora, Max-DOAS, etc.).After that, we improved the accuracy of retrieval algorithm and released GEMS version two data in November last year. In this version two data, we found improvements needed in a priori data, cloud data, and surface reflectance data. In this present study, we introduce the difference and improvements GEMS version two and one data.
Magmatic response to the subduction initiation of Early Cretaceous Nidar Ophiolite Complex, eastern Ladakh, NW Himalaya
Authors: Imayama Takeshi , Sato Akinori , Dutta Dripta , Kaneda Yasuaki , Watanabe Shota , Hasegawa Takeshi , Minami Masayo , Wakasugi Yuki , Wakaki Shigeyuki , Keewook Yi
Published: February 2023

Early Cretaceous Nidar Ophiolite Complex (NOC, eastern Ladakh) is associated with the north-dipping supra-subduction of the Neo-Tethyan Ocean along the Indus suture zone. The supra-subduction zone ophiolite formed in the forearc setting records the magmatic response to the subduction initiation, but the magmatic evolution in the NOC is poorly constrained. The low-Ti gabbros have low SiO2 in whole-rock composition and high Mg# in clinopyroxene. They also record highly depleted magma In contrast, dolerites and basalts have relatively higher SiO2 in whole-rock composition and lower Mg# in clinopyroxene, with flat REE patterns accompanied by fractional crystallization. Significant variation in Yb content relative to Tb/Yb ratio also supports fractional crystallization from gabbros to basalts. In Th/Yb-Nb/Yb diagram, all samples plot in the region from the MORB type to the island arc tholeiite. The Nd-Sr isotopes and high Ba/La ratio suggest that the NOC was originally derived from a single depleted mantle source similar to the MORB and was subsequently affected by hydrothermal alteration, resulting in greenschist- to lower amphibolite-facies overprint to form albite, actinolite, epidote and chlorite. Detrital zircon U-Pb ages from volcanic sediments associated with the NOC concentrated at ca. 136 Ma, representing the timing of the main magmatic phase in the NOC. Our data, combined with the geochronological and geochemical data in previous studies, suggest that the low-Ti, highly depleted magma in the NOC was firstly generated at extensional spreading in the upper plate during subduction initiation, and then changed to island arc tholeiite composition with the development of the subduction zone during Early Cretaceous.
The COllaborative Carbon Column Observing Network COCCON: Showcasing GHG observations at the COCCON Tsukuba site
Authors: Frey Matthias Max , Morino Isamu , Ohyama Hirofumi , Hori Akihiro , Dubravica Darko , Hase Frank
Published: February 2023

Greenhouse gases (GHGs) play a crucial role regarding global warming. Therefore, precise and accurate observations of anthropogenic GHGs, especially carbon dioxide and methane, are of utmost importance for the estimation of their emission strengths, flux changes and long-term monitoring. Satellite observations are well suited for this task as they provide global coverage. However, like all measurements these need to be validated.The COllaborative Carbon Column Observing Network (COCCON) performs ground-based observations to retrieve column-averaged dry air mole fractions of GHGs (XGAS) with reference precision. The instrument used by the network is the EM27/SUN, a solar-viewing Fourier Transform infrared (FTIR) spectrometer. COCCON data are of high accuracy as COCCON uses species dependent airmass-independent and airmass-dependent adjustments for tying the XGAS products to TCCCON (Total Carbon Column Observing Network) and thereby to the World Meteorological Organization (WMO) reference scale. Moreover, instrument specific characteristics are measured for each COCCON spectrometer, and taken into account in the data analysis.Here we first introduce the COCCON network in general and summarize its capabilities for various challenges including satellite and model validation, long-term observation of GHGs, and local and regional GHG source emission strength estimations. By example of the COCCON Tsukuba station we highlight in detail its usefulness for the above-mentioned applications.
Recent Trend of Cold Winters Followed by Hot Summers in South Korea due to the Combined Effects of the Warm Western Tropical Pacific and North Atlantic in Spring
Authors: Myoung Boksoon
Published: February 2023

This study finds a significant negative correlation between the December–February mean surface temperature (Ts_DJF) and the following June–August mean surface temperature (Ts_JJA) in South Korea for the period 1991–2017. This indicates that colder winters tend to precede hotter summers with extreme seasonality, while mild winters generally precede mild summers. This winter-to-summer association can be attributed to persistent atmospheric circulation anomalies on the Eurasian continent during the preceding winter and spring characterized by cyclonic circulations in Europe and East Asia and anti-cyclonic circulation in the Arctic regions. Resembling a negative Arctic Oscillation (AO) pattern combined with a negative Polar/Eurasia (PE) pattern, these atmospheric patterns tend to cause colder winters in South Korea and to increase the springtime sea surface temperatures in the western tropical Pacific (WTP) and in the North Atlantic (tripole pattern, NATRI). High WTP and NATRI values induce summertime anti-cyclonic circulations and then hotter summers in Korea with different pathways, the former via northward Rossby wave propagation in response to strong convection over a warm Philippine Sea and the latter via both extratropical Rossby wave propagation from the North Atlantic to East Asia and tropical connections from the tropical Atlantic to the Indian Ocean and then increased summer precipitation in South Asia. Under the opposite conditions (e.g., positive AO and PE phases in winter and negative WTP and NATRI), mild summers are preceded by mild winters. Since the early 1990s, the aforementioned atmospheric circulation anomalies during winter have shown greater persistence, creating the negative correlation between Ts_DJF and Ts_JJA. These findings provide useful information for the long-lead prediction of summer temperatures and heat waves in South Korea.