bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential Greenhouse Gas emissions reductions from simple changes to residential showering
Authors: Liang Xiaohong , Kenway Steven , Bors Julijana , Radion Andrew , Pamminger Francis
Published: February 2023

As part of the Net Zero Carbon Water Cycle Program (NZCWCP) for Victoria state in Australia, we have sought to understand the potential to reduce household energy consumption and related Greenhouse Gas (GHG) emissions by influencing water use. Digital metering data disaggregated into 57 million discrete water usage events across 105 households at a resolution of 10 millilitres at 10 second intervals from June 2017 to March 2020, from a previous Yarra Valley Water (Melbourne, Australia) study, was analysed, together with the dynamic relationship between the multiple energy sources (natural gas, grid electricity, solar) used to heat water for showers in each hour of the day. Water-related energy (WRE) use, including water desalination and treatment, pumping, heating, wastewater collection and treatment, comprised 12.6% of Australia’s primary energy use in 2019. Water heating (by natural gas and electricity) comprised the largest component of WRE use for across residential, commercial, and industrial sectors. Furthermore, 69% of Victoria’s total water usage was by residential customers in 2020-2021. WRE GHG emissions were around 3.8% of Victoria’s total GHG emissions in 2018. Showers (~50% of residential WRE), system losses (~27% of residential WRE), and clothes washers (~9% of residential WRE) are the three largest components of WRE consumption. The main objective of this work is the creation of industry-accessible tools to improve knowledge and management options from the understanding of reductions in cost and GHG emissions from household showering WRE use. Potential options considered, to reduce water and energy use, as well as associated GHG emissions and customer utility bills, include (a) behaviour management such as water and energy pricing to change time of use behaviours, and (b) the adoption of efficient shower head improvements. Shower WRE and GHG emissions were found able to be strongly impacted by small changes in daily routines. GHG emissions reduction from showering could be reduced up to 20 (in summer) - 22% (in winter) by shifting demand time of showering or replacing residential showerheads. Extrapolated to state and Australian scales, reductions in water usage could be up to 14 GL (Victoria) and 144 GL (Australia), and reductions in GHG emissions 1,600 ktCO2eq (Victoria) and 17,300 ktCO2eq (Australia). It provides fundamental new information which could inform a suite of new management options to impact water-related energy from showers, and related GHG emissions and customer water and energy cost.
3D MHD Modeling of Interplanetary Solar Wind Using Self-Consistent Boundary Condition Obtained from Multiple Observations and Machine Learning
Authors: Shen Fang , Yang Yi , Feng Xueshang
Published: February 2023

Three-dimensional (3-d) magnetohydrodynamics (MHD) modeling is a key method for studying the interplanetary solar wind. In this article, In this paper, we introduce a new 3-d MHD solar wind model driven by the self-consistent boundary condition obtained from multiple observations and Artificial Neural Network (ANN) machine learning technique. At the inner boundary, the magnetic field is derived using the magnetogram and potential field source surface extrapolation; the electron density is derived from the polarized brightness (pB) observations, the velocity can be deduced by an ANN using both the magnetogram and pB observations, and the temperature is derived from the magnetic field and electron density by a self-consistent method. Then, the 3-d interplanetary solar wind from CR2057 to CR2062 are modeled by the new model with the self-consistent boundary conditions. The modeling results present various observational characteristics at different latitudes, and are in good agreement with both the OMNI and Ulysses observations.
East Africa's elusive LAB
Authors: Bastow Ian , Rooney Tyrone
Published: February 2023

A consensus has emerged over the past two decades that significant extension at crustal depths in the northern East African Rift is achieved not by ductile stretching but by magma intrusion. The implications of this for crustal structure and Moho architecture have all been the focus of intense study. East Africa's deep convecting mantle has also been the focus of intense research, with most workers now accepting of the super-plume model over traditional 'Morgan' plumes (albeit with some ongoing discussion concerning the precise internal architecture of the superplume).  In contrast, our understanding of East Africa's lithospheric mantle and, in particular, the depth to the lithosphere-asthenosphere boundary (LAB), remains remarkably poor.  For example, some studies have postulated that no lithospheric mantle exists below large parts of Afar and the Ethiopian rift where magma-assisted rifting is now underway; others have argued to the contrary, asserting that a melt-rich lithospheric mantle is essential to explain first order observations including mantle seismic anisotropy, and the depth at which melts last re-equilibrated with the mantle prior to eruption. Here we will review some of the seismological and petrological evidence that has featured in this debate, including critically assessing the efficacy of different seismological techniques for determining LAB depth in magmatic versus non-magmatic sectors of the EAR.  We show that petrology contributes strongly to the EAR LAB debate, with the added benefit that it allows the assessment of plate thickness through time.  Finally, we look to recent observations from the Turkana Depression, where a lithosphere thinned during multiple, superposed episodes of rifting, offers the chance to assess lithosphere-asthenosphere interactions in more detail than can be achieved elsewhere along the rift.
Context studies of Parker Solar Probe and Solar Orbiter flybys using synthetic in-situ and remote-sensing observations
Authors: Szente Judit , van der Holst Bartholomeus , Landi Enrico
Published: February 2023

We use the Space Weather Modeling Framework's Alfvén Wave Solar atmosphere Model to simualte the origin and evolution of solar wind plasma during multiple SO and PSP flybys.   Synthetic spectral and narrow band imaging, synthetic spectra and in-situ plasma data are used to study the heating and acceleration of the coronal plasma and solar wind in the inner heliosphere. We identify large scale structures the spacecrafts pass through: current sheet crossings, plasmas of different origins. When data is available we simultaneously simulate non-equilibrium ionization of minor heavy ions in the solar wind along the SO trajectory and study how the plasma charge states represent the different origins of solar wind and also how the out-of-equilibrium charge states change the synthetic remote sensing observations compared to using equilibrium assumptions. 
A Study of Ephemeral Wetland Types According to Water Level Changes in Lava Forests
Authors: Park Minji , Kwak Sangeun , Yang Ju-eun , Park Eun-ha , Lee Bora , Seol Ara
Published: February 2023

Jeju Island is a basalt volcanic island located in Korea, and lava forests are distributed in the east and west of the island. Wetlands play a more significant role in lava forest than other forests, due to high volume of underground water as a result of high rainfall permeability rates averaging 67%. In particular, the lava forests of eastern Jeju Island is designated as a protected Ramsar wetland, featuring both a few permanent wetlands and several ephemeral wetlands. Notably, ephemeral wetlands show higher species diversity than permanent wetlands. A study was conducted to understand the types of ephemeral wetlands and investigate the characteristics. Water level sensors were installed in five wetlands for three years beginning in 2020. A three-type classification system was created: rugged topography with many large stones (Wetland ‘Type A’), concave topographies (Wetland ‘Type B’), and sedimentary topographies (Wetland ‘Type C’). The highest water levels were recorded in 2020 at all study sites. ‘Type A’ had the highest water levels (1.5m; 2.7m) before quickly draining (2.9mm/h; 5mm/h), and was the first to zero out. ‘Type B’ achieved the mid-range of recorded water levels (0.7m; 0.8m), and drain rate (1.3mm/h; 1.4mm/h). ‘Type C’ had the lowest highest water level (0.4 m), and the slowest drain rate (0.8 mm/h). In the same 2020 observation period, water levels were maintained at 0.1m for both Type A wetlands were maintained for 72 days and 40 days, ‘Type B’ for 111 days and 92 days, and ‘Type C’ for 221 days. The submersion period during which wetlands were submerged decreased by 7% in 0.1m water level and 19% in 0.25m water level in 2021 compared to 2020, and 37% in 0.1m water level and 42% in 0.25m water level in 2022 compared to 2020. Additionally, there was no observed difference in total annual precipitation in 2020 and 2021, but there was variation in maximum daily rainfall. In 2022, the total annual precipitation was 35% lower than in 2020. Therefore, ephemeral wetland environment change every year, as the amount of level of ephemeral wetlands seems to be affected not only by both total annual precipitation and but also by how concentrated rainfall is within shorter time periods. These factors have a significant impact on the distribution of rare and special plants and the diversity of herbaceous species distributed by the wetland types.
Large-scale estimation of surficial sediment size in alpine landforms using UAV photogrammetry and machine learning.
Authors: Zegers Gerardo , Garces Alex , Hayashi Masaki
Published: February 2023

Accurate estimation of surficial sediment size in alpine landforms such as talus slopes, rock glaciers, and moraines is crucial for understanding geomorphologic processes and predicting the potential impact of natural hazards. Traditional methods for measuring sediment size in these environments can be time-consuming and labor-intensive. Additionally, they are usually applied to selected areas and are rarely used to cover larger areas, making the development of more efficient approaches essential. This study presents a new method for estimating large-scale surficial sediment size based on unmanned aerial vehicle (UAV) photogrammetry and combining SediNet and PebbleCountAuto image analysis methods. SediNet is a configurable machine-learning framework for estimating either (or both) continuous and categorical variables from a photographic image of clastic sediment. SediNet can achieve subpixel resolutions because the dimensions of the grains aren't being measured directly. However, site-specific sediment sizes are necessary to train this model. On the other hand, PebbleCountAuto does not require any site calibration by using segmentation methods to delimitate the grains automatically and provide a full grain-size distribution. Our proposed methodology trains the SediNet model using the sediment sizes outputs of the PebbleCountAuto method. Our study area is the upper part of the Lake O'Hara watershed in the Canadian Rockies, composed of talus slopes and a large ice-cored moraine. We performed two types of UAV flights; high-altitude flights (~100 m height) to cover the whole study area with medium-to-high resolution orthomosaic (pixel resolution 3 cm) and low-altitude flights (~25 m height) at smaller patches to achieve high-resolution orthomosaic (pixel resolution 5-8 mm). First, the sediment size was estimated in the high-resolution patches with the PebbleCountAuto method. Then, these results were used to train the SediNet model and generate a large-scale sediment size estimation. Our results show that this combination of methods is a reliable and efficient approach for accurately estimating sediment sizes in alpine landforms. The use of UAV photogrammetry allows for the rapid and cost-effective collection of high-resolution imagery, while the combination of SediNet and PebbleCountAuto provides robust estimates of sediment size over large areas. This new method can improve our understanding of geomorphologic processes and hazard assessment in these environments.
Calcification response of Emiliania huxleyi under calcite and aragonite sea
Authors: Wang Han , Ruiz-Pino Diana , Gardin Silvia , Probert Ian , Langer Gerald
Published: February 2023

The magnesium/calcium ratio of seawater has oscillated throughout the geological time between aragonite seas (>2) and calcite seas (<2), which strongly influenced coccolithophores biocalcification, along with the variation of ocean temperature and pH. Here we proposed to analyze in a concomitant way the effect of temperature and pH together with Mg/Ca on coccolithophores. In this study, we cultured Emiliania huxleyi (RCC963) under a range of Mg/Ca ratios (Mg/Ca: 0.2, 1, 5), temperature (15℃, 21.5℃, 28℃) and pH (7.4, 7.8, 8.2) to evaluate the cell adaption and calcification sensitivity by measuring the growth rate(μ), Photosystem Ⅱ efficiency (Fv/Fm), calcification rate and coccolith morphology. We have found that in the calcite sea, E. huxleyi is more vulnerable to changes of temperature and pH than it is in the aragonite sea. The coccolith morphology also supports the different response to the Mg/Ca ratio variation where more malformed and incomplete coccoliths were observed with the decreasing of temperature and pH. Further exploration is needed to understand the multi-changes in environmental parameters in the distribution of Mg in coccoliths of E. huxleyi and morphogenesis. 
Competing climate feedbacks of ice sheet freshwater discharge in a warming world
Authors: Li Dawei , DeConto Robert , Pollard David
Published: February 2023

Earth's polar ice sheets are projected to undergo significant retreat in the coming centuries if anthropogenic warming were to continue unabated, injecting freshwater stored on land over millennia into oceans and raise the global mean sea level. Ice sheet freshwater flux alters the status of ocean stratification and ocean-atmosphere heat exchange, inducing oceanic surface cooling and subsurface warming, hence an impact on the global climate. How the climate effects of ice sheet freshwater would feedback to influence the retreat of ice sheets, however, remains unsettled. Here we develop a two-way coupled climate-ice sheet modeling tool to assess the interactions between retreating polar ice sheets and the climate, considering a variety of greenhouse gas emission scenarios and modeled climate sensitivities. Results from coupled ice sheet-climate modeling show that ice sheet-ocean interactions give rise to multi-centennial oscillations in ocean temperatures around Antarctica, which would make it challenging to isolate anthropogenic signals from observational data. Future projections unveil both positive and negative feedbacks associated with freshwater discharge from the Antarctic Ice Sheet, while the net effect is scenario-dependent. The West Antarctic Ice Sheet collapses in high-emission scenarios, but the process is slowed significantly by cooling induced by ice sheet freshwater flux.
The Atmospheric Waves Experiment
Authors: Pautet Pierre-Dominique , Taylor Michael John , Zhao Yucheng , Forbes Jeffrey , Fritts David , Eckermann Stephen , Liu Han-Li , Snively Jonathan , Janches Diego , Lamborn Burt , Latvakovski Harri , Syrstad Erik
Published: February 2023

The Atmospheric Waves Experiment (AWE) is a new NASA mission aimed at investigating the effects of tropospheric weather on space weather. An Advanced Mesospheric Temperature Mapper (AMTM) airglow imager will be deployed on the International Space Station (ISS) in December 2023. This proven instrument will map the nighttime mesospheric temperature at the altitude of the hydroxyl (OH) layer (~87 km) during two years, providing 2D gravity wave (GW) fields over a 600 km field-of-view, every second.Four state-of-the-art models will also help achieving the three science objectives:Quantify the seasonal and regional variabilities and influences of GWs near the mesopause,
Identify the dominant dynamical processes controlling GWs observed near the mesopause,
Estimate the wider role of GWs in the Ionosphere-Thermosphere-Mesosphere (ITM).
This presentation will give an overview of the AWE mission and describe the future data levels using synthetic images.
Mapping of traffic emissions from a busy road in a rural village using gaseous perfluorocarbon tracers
Authors: Matthews James , Khan Anwar , Shallcross Dudley
Published: February 2023

The exposure of populations to toxic traffic emissions is an important concern and significant research effort has been put into measuring and modelling exposure to traffic related pollutants within urban areas. It is also the case that busy trunk roads can pass through villages and towns subjecting those populations to both particulates and pollutant gases. Often, smaller villages in urban areas have complex topographies and provide a different environment to cities with regard to pollutant dynamics. Perfluorocarbon (PFC) trace gases are useful to measure the flow of gases within an area [1]. PFCs are inert, non-depositing and non-toxic and can be detected at low levels using sufficiently sensitive mass spectrometers and preconcentration devices [2]. To understand the passage of gaseous pollutants from a busy road passing through a rural village in Southern England, PFCs were released from a fixed and a moving source and sampled in several locations downwind.Eight experiments occurred over three different measurement periods, three in June 2021, two in February 2022 and two in May 2022, covering different times of day and meteorological and road conditions. In each experiment, perfluoromethylcyclohexane was released from a fixed position approximately 400 m downwind of the road (July, Feb) or on the road west of the village (May) for 15 minutes, while 1,3-perfluorodimethylcyclohexane was released from the passenger side of a moving vehicle travelling with the flow of traffic through the village. 30-minute Tedlar bag samples were collected in up to 10 locations, some of these locations also measured PM10, PM2.5 and PM1 using an Alphasense N3 optical particle sensor. Bag samples were stored separately from release equipment and transported to Bristol University School of Chemistry for analysis using the methodology described in [3].Wind directions during the experiments were south westerly and westerly. The highest tracer concentrations from the moving source were often measured within a bus stop roadside in the centre of the village, whereas the static release was highest at a residential roadside sample on the western side of the village. Two samples were taken roadside in a church yard and at the top of the spire, the moving release was consistently higher at ground level, but from the stationary release the tracer was predominantly higher in concentration at roof height.  [1] Shallcross, D. E. et al. 2009. Atmospheric Science Letters, 10(2), 59-65.[2] Simmonds, P. G. et al .1995. Analytical Chemistry, 67(4), 717-723.[3] Matthews, J. C. et al. 2020. Boundary-Layer Meteorology, 175(1), 113-134.
Attribution of the 2022 extratropical storm Fiona
Authors: Malinina Elizaveta , Gillett Nathan
Published: February 2023

In late September 2022, the Atlantic Hurricane Fiona transitioned to an extratropical cyclone making a landfall in the Canadian Atlantic provinces and setting a new national lowest pressure record. The insured damage from the resulting windstorm and flooding is estimated to be 800 million CAD (600 million USD).In this study, we analyze the maximum daily near-surface wind speeds in Atlantic Canada using reanalysis and CMIP6 HighResMIP data. According to our preliminary results from ERA5 reanalysis, the 2022 Fiona wind speeds were the highest in Atlantic Canada since 1950, with an estimated return period of 500 years. Additionally, using HighResMIP data from the models with a spatial resolution exceeding 56x56 km, we compare the wind speeds in the current climate with those from 1950-1969 and in 2031-2050 under the highres-future scenario, similar to RCP8.5. While currently in Atlantic Canada, there is no statistically significant increase in the maximum daily wind speeds in comparison to 1950-1969 climate, the increase in the mid-21st century wind speeds in comparison to the 1950-1969 period is statistically significant with the 2022 event being 3.8 times more likely. We apply similar analysis to the data from CAM5 model as well as to the CMIP6 precipitation data in the region.
Isotope diffusion in ice enhanced by vein-water flow
Authors: Ng Felix
Published: February 2023

Diffusive smoothing of signals on the water stable isotopes in ice sheets limits the climatic information retrievable from these ice-core proxies. Previous theories explained how, in polycrystalline ice below the firn, fast diffusion in the network of intergranular water veins short-circuits the slow diffusion in crystal grains to cause “excess diffusion”, enhancing the signal smoothing rate above that implied by self-diffusion in ice monocrystals. However, the controls of excess diffusion remain poorly understood. I show that vein-water flow amplifies excess diffusion, by altering the three-dimensional field of isotope concentrations and isotope transfer between the veins and crystals. The rate of signal smoothing depends not only on temperature, vein and grain sizes, and signal wavelength, but also on vein-water flow velocity, which can increase the rate by 1 to 2 orders of magnitude. This modulation can significantly impact signal smoothing at ice-core sites in Greenland and Antarctica, as demonstrated by simulations for the GRIP and EPICA Dome C sites, which show sensitive modulation of their diffusion-length profiles when vein-water flow velocities reach ~ 101–102 m yr–1. Thus vein-flow mediated excess diffusion may help explain the mismatch between modelled and spectrally-derived diffusion lengths in other ice cores. I also show that excess diffusion biases the spectral estimation of diffusion lengths from isotopic signals and the reconstruction of surface temperature from diffusion-length profiles. These findings caution against using the single-crystal isotopic diffusivity to represent the bulk-ice diffusivity. The need to predict excess diffusion in ice cores calls for extensive study of isotope records for its occurrence and better understanding of vein-scale hydrology in ice sheets.
Characteristic Times for Radiation Belt Drift Phase Mixing
Authors: Lejosne Solène , Albert Jay M.
Published: February 2023

One of the key assumptions of radiation belt modeling based on a three-dimensional Fokker-Planck equation is that trapped particle fluxes do not depend on the drift phase (i.e., the azimuthal angle, or magnetic local time, MLT). It is usually considered that MLT-dependent structures (such as particle injection signatures and subsequent drift echoes) are rapidly smoothed out by drift phase mixing. Yet, the characteristic times for radiation belt drift phase mixing are not well known.In this presentation, we show the existence of a naturally occurring phase mixing process in the presence of field fluctuations. This process complements the observational phase mixing due to the finite resolution of the measuring instrument.We present a first quantification for the characteristic time of natural phase mixing and we discuss the implications in terms of radiation belt modeling.
Isotopic composition as a tracer of different source contributions to stream flow in the glacierized catchments of Central Asia
Authors: Saidaliyeva Zarina , Shahgedanova Maria , Yapiyev Vadim , Wade Andrew , Akbarov Fakhriddin , Esenaman Mukhammed , Kapitsa Vassiliy , Kassatkin Nikolay , Kayumova Diliorom , Rakhimov Ilkhomiddin , Satylkanov Rysbek , Sayakbaev Daniyar , Severskiy Igor , Petrov Maksim , Usubaliev Ryskul , Umirzakov Gulomjon
Published: February 2023

The mountains of Central Asia are water towers servicing the arid downstream regions and maintaining irrigation and food production. There are several sources of runoff: liquid precipitation, snowpack, glacier ice, ground ice (including rock glaciers and permafrost), and ground water. The relative contributions of different water sources to stream flow are poorly quantified and its improved understanding will reduce uncertainty in hydrological modelling and projections of changes in water resources. In 2019-21, an extensive sampling programme was conducted to quantify the relative contributions of water sources to stream flow in the Tien Shan and Pamir-Alai using stable water isotope tracers (SWI) of oxygen and hydrogen. Samples of the event-based precipitation, river discharge taken daily or twice-daily at the designated sampling points and every fortnight along the river courses, and water sources were collected in the glacierized catchments in Kazakhstan (Ulken Almaty and Kishi Almaty catchments), Kyrgyzstan (Ala-Archa and Chon-Kyzyl Suu), Tajikistan (Varzob and Kafornihon), and Uzbekistan (Chirchik). The samples were processed using Picarro isotope analyser. A data set of SWI ratios from approximately 6000 samples has been produced and analysed. It is the first comprehensive SWI database in Central Asia contributing to understanding of regional and global isoscapes and water resources. The local meteoric water line (LMWL) was developed from the event-based precipitation samples. It is approximated as δD = 7.6δ18O + 8.7. The values of SWI in precipitation exhibit a clear annual cycle and depend on precipitation type (rain, snow, and mixed). The derived seasonal SWI values are different from those available from the Water Isotopes Database being nearly twice as high in winter. Snow, glacier ice and permafrost exhibit distinct isotopic signatures although these vary between the basins. Glacier ice in the Chirchik basin appears to be more depleted than elsewhere. Rock glaciers were sampled in the Ulken Almaty basin showing SWI ratios similar to those of glacier ice but both are distinct from permafrost. These results point at the feasibility of the application of the mixing model and end-member mixing analysis approaches to the partitioning of runoff and quantifying relative contributions of different water sources in the Tien Shan and Pamir-Alai. This is a policy-relevant task under the conditions of climate change.
Changes in Tree height–diameter allometry for temperate forests: A large periodical observational study
Authors: Kim Moonil , Park Taejin , Ko Youngjin , Choi Go-Mi , Lee Woo-Kyun
Published: February 2023

Forest biomass is used as a representative factor for forest size, forest maturity, and forest productivity, so quantitative evaluation is very important not only for management and harvest but also for the evaluation of ecosystem functions and services including CO2 absorption. The allometric equation is a method of estimating the value of each part through the relative growth rate of plants and is a methodology widely used from the past to the present. Recently, studies have shown that the relative growth system of trees is changing due to the increase in CO2 concentration in the atmosphere and the resulting climate change, raising the need to review the previously developed relative growth and coefficients. In this study, the height-DBH relative growth relationships of four major tree species in Korea [(Pinus densiflora (PD), Larix kaempferi (LK), Quercus variabilis (QV), and Quercus mongolica (QM)] were analyzed using the 5―7th NFI data. Furthermore, these results were compared with the present yield table from the national institute for forest science. As a result of the analysis, it was found that the expected height value for the same DBH increased as the NFI progresses. For example, as a result of model analysis, the expected height for PD, LK, QV, and QM for DBH 25cm were 12.48, 19.17, 14.47, and 13.19m in the 5th NFI data, respectively. From the 7th NFI data, they were estimated as 13.61 (+9.1%), 21.58 (+12.7%), 15.76 (+8.9%), and 13.93 m (+5.6%), respectively. These results indicate that the current growth of major tree species in South Korean forests is more active in height growth than in diameter growth under climate change when compared with the height-DBH development trends by tree species identified through past survey data.
Sea animals promote carbonyl sulfide (OCS) emissions from Antarctic tundra
Authors: Zhang Wanying , Zhu Renbin , Jiao Yi , Rhew Robert C. , Sun Bowen , Rinnan Riikka , Zhou Zeming
Published: February 2023

Carbonyl sulfide (OCS), the most abundant atmospheric sulfur-carrying gas, can contribute to regulating Earth’s radiative balance through forming sulfate aerosols. The bryophyte-dominated tundra lying over the ice-free Antarctica is an important terrestrial carbon sink and provides colonies for sea animals, such as penguins and seals, which remains hitherto unexplored concerning OCS biogeochemistry. Here, we measured OCS fluxes from the Antarctic tundra and coupled their fluxes to soil biogeochemical properties to explore OCS production and degradation processes. The bryophyte-dominated normal upland tundra was an OCS sink at -0.97 ± 0.57 pmol m-2 s-1, resulting from both bryophytes and OCS-metabolizing enzymes (e.g., carbon anhydrase, nitrogenase) secreted by soil microbes, such as Acidobacteria, Verrucomicrobia, Chloroflexi, and Mortierellomycota. In comparison, tundra within sea animal colonies was an OCS source up to 1.35 ± 0.38 pmol m-2 s-1, due to the input of organosulfur from sea animals and the animal-induced anaerobic soil environment, which promoted simultaneous abiotic OCS production in soil, and outweighed the biogenic OCS uptake by bryophytes and soil microbes. Furthermore, sea animal colonization shaped the soil microenvironment, affecting nutrient levels, pH and moisture, which may have reduced the abundances of OCS-metabolizing microbes and thereby OCS degradation and further unveiled concurrent OCS production. Basic calculation suggested that sea animals contribute about 107 metric tons yr-1 of OCS-S to the atmosphere. The strength of this OCS source is expected to increase in response to Antarctic warming. Overall, tundra ecosystems are important interfaces for OCS exchange and sea animals exert an impact on the sulfur cycle in coastal Antarctica.
Fuzzy c-mean clustering joint inversion of magnetotelluric (MT) and gravity data-sets using unstructured tetrahedral meshes
Authors: Kangazian Mitra , Farquharson Colin
Published: February 2023

Minimum-structure, or Occam’s, style of inversion deals with the fundamental non-uniqueness of the inverse problem by finding the simplest Earth model that reproduces the observations. As an additional consequence of this approach, minimum-structure inversion is also reliable and robust. Because of these reasons, it has been extensively utilized in mineral and petroleum exploration problems, and lithospheric studies. The method has been adapted and extended in many ways to obtain more reliable and realistic models of the Earth’s subsurface. Joint inversion of geophysical data-sets is one of the most important extensions of minimum-structure inversion. This method can reduce the non-uniqueness of the inverse problem by combing two, or more, different geophysical data-sets in a single inverse problem. Different geophysical methods have different sensitivity to different physical properties, hence, it is hoped that the null space for one type of data can be spanned by the other.Joint inversion algorithms can be divided into two main categories, structural-based and petrophysical-based joint inversion methods, depending on the coupling measure used between the physical property models. We have adopted the fuzzy c-mean (FCM) clustering technique which is a petrophysical-based method to jointly invert MT and gravity data-sets. The optimization of this method is not as challenging as for structural-based approaches. We have also performed constrained FCM clustering for independent MT and gravity inversions to compare the constructed models of this method with the joint inversion, and independent MT and gravity inversions. The FCM clustering method makes effective use of statistical petrophysical data which may exist in complex geological structures, or can be anticipated, to encourage the inverted physical property values to move towards the a priori petrophysical data as target clusters.The capabilities of the joint and constrained FCM clustering inversion are evaluated on synthetic and real examples. The constructed density and conductivity models from the joint inversion have a more plausible representation of the true model’s geometry and have a reasonable range of the recovered physical property values compared to the independent constrained FCM clustering technique and independent unconstrained MT and gravity inversions.Keywords: Fuzzy c-mean clustering, Gravity, Joint inverse problem, MT, Unstructured tetrahedral mesh
An Idealized Study of Cold Air Outbreaks
Authors: Papazian Karen , Kirtman Ben
Published: February 2023

Cold air outbreaks (CAOs) have large societal and environmental impacts, such as agricultural losses, infrastructure damage, changes in atmospheric circulation, etc. As the Earth experiences a climate crisis, the focus on CAOs has been diminishing, but extreme CAOs continue to occur which society is gravely underprepared for. This study looks to explore how CAOs evolve in a changing climate through idealized modeling. In addition to climate modeling, observational data is used to compare the current dynamics of CAOs to that expected in a climate change scenario. Observational data from the NCEP-NCAR Reanalysis project is used in addition to model simulations from the Community Atmospheric Model - version 5 (CAM5), of the NCAR Community Earth System Model v1 (CESM1). In the model simulations, this study prescribes sea surface temperature to a fully ocean-covered planet, an aquaplanet simulation. These differing surface temperature gradients were chosen to resemble potential global climate change scenarios and extreme climate change scenarios. The use of aquaplanet simulations creates an idealized environment conducive of understanding the mechanisms of CAOs. As the pole to equator surface temperature gradient is eliminated, echoing an extreme climate change scenario where the poles warm more than the TR, CAOs continue to be present. With these differing aquaplanet simulations this study aims to further understand the physical mechanisms of CAOs, and the role dynamics plays in their frequency and intensity.
Assessing soil carbon cycling as a function of intercropped maize-forage systems and nitrogen rates using 13C natural abundance
Authors: Vieira da Mota Neto Laudelino , Valadares Galdos Marcelo , Eliodoro Costa Vladimir , Antonio Rosolem Ciro
Published: February 2023

Intercropping maize along with forages fertilized with N can potentially increase soil carbon sequestration, contributing to climate change mitigation. However, there is a lack of knowledge if the input of new C sources in this production system impacts the cycling of the original soil C and SOM fractions, especially in tropical soils. To investigate this, soil samples were taken up to 80 cm depth from a 7-year experiment where ruzigrass (Urochloa ruziziensis), palisadegrass (Urochloa brizantha) and Guinea grass (Megathyrsus maximus) were intercropped with maize fertilized with (270 kg N ha-1) or without N. In these samples, SOM was fractionated by size into particulate (POM) and mineral-associated (MAOM) organic matter and submitted to 13C natural abundance measurements. Intercropping with Guinea grass reduced the δ13C values in comparison to ruzigrass and palisadegrass, especially under N fertilization. Forage grasses reduced the δ13C values up to 40cm, indicating the contribution of the grasses for the cycling of the original carbon of the soil. Nitrogen supply increased the contribution of C from the grasses to the POM fraction if compared to the no N application. Further, 13C  in POM at 0-10 and 10-20 cm differed from deeper layers, probably due the above- and belowground C inputs on the uppermost soil layers. Under N supply, Guinea grass lowered the δ13C value, which did not occur in the palisade and ruzigrass treatments. In contrast to POM, the δ13C values of MAOM decreased in all depths, with the highest change at the uppermost soil layer. Our findings showed that intercropping influenced the cycling of total C and SOM fractions , with differences in the soil profile. However, only Guinea grass changed δ13C values under N supply.
Cenozoic and Late Cretaceous Apparent Polar Wander of the Pacific Plate: Implications for True Polar Wander and Global Plate Motion Circuits
Authors: Gordon Richard , Woodworth Daniel , Gaastra Kevin
Published: February 2023

The apparent polar wander (APW) path of the Pacific plate during Cenozoic and Late Cretaceous time has important paleogeographic, global tectonic, geodynamic, and paleoclimatic implications. Here we present recent progress on our assessment of Pacific plate APW with a focus on new poles determined from analysis of the skewness of marine magnetic anomalies due to seafloor spreading, which produces high precision paleomagnetic poles.Our recent and new results include paleomagnetic poles for chron C24r (57–54 Ma; Woodworth et al. 2023), chron 21n (48−46 Ma; Woodworth et al. in preparation), chron 27r (63−62 Ma; Gaastra et al., in preparation), and chron 30n−31n (69−66 Ma; Ritchey et al., in preparation).  The new chron 24r pole extends the northward progression of the 69–58 Ma track in the previously determined Pacific plate apparent polar wander path beyond the southern end of the 46–10 Ma track, which is now extended by our chron 21n pole.  That the two tracks overshoot one another implies either a brief interval during which the Pacific plate moved substantially and rapidly southward relative to a mantle reference frame or to an episode of true polar wander (TPW, the re-orientation of the solid Earth relative to the spin axis).  The reconstructed plate geometry and relative plate motions are inconsistent with ancient plate driving forces having been capable of driving the plate southward.  Considering our results together with drill-core paleomagnetic paleolatitudes, we find that the most likely explanation is a ≈7° episode of TPW between ≈54 Ma and ≈50 Ma.  The new high precision paleomagnetic poles for the Pacific plate, when compared with continental paleomagnetic results from Torsvik et al. (2012) reconstructed to a common frame of reference, allow an updated test of two plate motion circuits relating the Pacific plate to the circum-Pacific continents. Analysis of the plate-motion circuit through Antarctica (or through Australia) continues to indicate a significant paleomagnetic misfit that increases with age during Cenozoic time up to a maximum of ≈7−8° at ≈50 Ma. Analysis of the fixed hotspot circuit indicates a smaller insignificant misfit of up to ≈5° that also increases with age.If the plate circuit through Antarctica is flawed, as indicated by the paleomagnetic results, any or all of the following may have contributed to the flaw: (1) intraplate deformation (cf., Kreemer & Gordon, 2014), (2) unrecognized diffuse oceanic plate boundaries (e.g., Gordon & Stein, 1992), (3) motion between East and West Antarctica not localized across mid-ocean ridge segments, and (4) horizontal extension across large expanses of submerged continental area in the south Pacific (e.g., Sutherland et al., 2020).
Assessing Air-sea CO2 Flux Products with Constraints from Atmospheric Inverse Analyses
Authors: Suntharalingam Parv , Chen Zhaohui , Shutler Jamie , Watson Andrew
Published: February 2023

Oceanic uptake of atmospheric CO2 has been estimated to remove ~25% of  global anthropogenic emissions in recent decades (1990-2020), and this flux displays significant decadal variability (Global Carbon Budget: Friedlingstein et al. 2022). Key contributors to this ocean CO2 flux estimate are data products derived from interpolated surface ocean pCO2 measurements combined with air-sea gas-exchange parameterizations.  Although derived from a common surface ocean CO2 database (Surface Ocean CO2 Atlas (SOCAT), Bakker et al. 2016), these data products display variations on regional and global scales due to differences in their underlying construction methodologies. Here we assess three widely cited air-sea CO2 flux products, namely, Landschutzer et al. (2016), Roedenbeck et al. (2014) and Watson et al. (2020).  Our assessment uses the GEOSChem-LETKF data assimilation system (Chen et al. 2020), together with atmospheric CO2 observations from the NOAA-ESRL global network of surface sites (Obspack_CO2_Globalviewplus, 2020).  The individual air-sea flux products are implemented as alternative representations of the ocean prior flux, and we derive optimized estimates of surface CO2 fluxes in a set of atmospheric inverse analyses with the GEOSChem-LETKF system. We assess the performance of the individual ocean flux products on regional and global scales using a range of metrics derived from the atmospheric inversions including model concentration bias, CO2 flux error reduction, and comparison to independent atmospheric measurements from surface sites and aircraft. We also compare the derived posterior ocean fluxes to estimates from global ocean biogeochemistry models and discuss the implications for closure of the global carbon budget.
Is the AMOC connected across all latitudes?
Authors: Rapanague María Jesús , Putrasahan Dian , Marotzke Jochem
Published: February 2023

The Atlantic Meridional Overturning Circulation (AMOC) is fundamental for the northward transport of heat and the vertical transport of carbon from the surface to the deep ocean in the North Atlantic Ocean, influencing the climate at both local and global scales. However, the mechanisms underlying the AMOC variability are still poorly understood, because of the lack of long-term observations and the challenge of representing key processes in standard climate models. Furthermore, assumptions widely accepted for several decades have re-entered the debate in recent years, such as the AMOC meridional coherence and the role of deep convection in the Labrador Sea in driving the AMOC variability and deepwater formation. New modeling and observational studies suggest that the overturning variability is not coherent between subtropical and subpolar latitudes on interannual to decadal scales and that climate models systematically exaggerate the importance of the Labrador Sea, pointing toward other regions like the Irminger Sea and the Nordic Sea as better candidates for deepwater formation.In this study, we aim to critically assess the long-held notion of meridional coherence in the AMOC, using output from high- and very-high-resolution model simulations. Specifically, we investigate how the meridional coherence of the AMOC changes when increasing model resolution, via spectral analysis of the MPI-ESM1.2 control simulations with resolutions of 1°, 0.4°, and 0.1°. Preliminary analysis using lead-lag time correlations indicates a high correlation and meridional coherence between the AMOC strength and mixed layer depth variability in the Labrador Sea for the coarsest resolution. However, when increasing the resolution this relationship disappears, and the AMOC is instead better related to overflow changes in the Denmark Strait and in the Nordic Seas. Additionally, the meridional coherence of the AMOC becomes unclear.
Breakdown coefficients of multiplicative cascades having asymmetrically distributed generators with bounded essential range
Authors: Aguilar Flores César , Carsteanu Alin Andrei
Published: February 2023

In previous work [Aguilar Flores et al., Stoch. Environ. Res. Risk Assess. (2021) 35: 1681-1687], distributional convergence of breakdown coefficients (BDCs) to symmetric probability distribution functions of weights in discrete-scale multiplicative cascades has been shown. Asymmetric weights distributions, however, cannot become the limiting functions of symmetric BDC distributions. A procedure has been devised and is presented herein for the computation of the limiting distributions in the aforementioned cases, involving a convolution that is identified with the first-level BDCs probability distribution, and thereby can be used for the purpose of model validation in otherwise non-ergodic single realizations of multiplicative cascade models.
Formation of secondary organic aerosols under various UV light intensities in a smog chamber
Authors: Lee Jae Young , Kim Hyun , Kim Jungdo , Jung Heon Young
Published: February 2023

The presence of anthropogenic organic compounds in aerosols can affect climate by altering the hygroscopicity of the aerosols and their behaviors as cloud condensation nuclei. Due to their importance, characteristics of atmospheric organic aerosols and their mixtures have been studied.Among atmospheric organic aerosols, secondary organic aerosols (SOA) have not been well known. However, understanding on the chemical and photochemical properties of SOA is necessary to forecast the concentration of ultrafine particles more accurately. One of the important factors affecting the formation of SOA is the intensity of light. The stronger the intensity of light, the more the photochemical reactions, and thus the more the SOA formation. Thus, in this study, we examined how the formation of secondary organic aerosols can be changed under various UV light intensity.  For this study, we used a smog chamber (1mm1.7m) with a Teflon or Tedlar bag used as a reactor. To provide ozone and clean air into the chamber, zero air generator (8301 LC, EcoTech, Australia) and gas dilution calibrator (Serinus CAL, EcoTech, Australia) were used. To detect ozone, NOx and particulate matters, ozone analyzer (Serinus 10, EcoTech, Australia), NOx analyzer (Serinus 40, EcoTech, Australia) and scanning mobility particle sizer (3938 Series, TSI, USA) were used, respectively. Input gas wasa mixture of NO, NO2, ozone and toluene, and set temperature varies from 25 to 26 C. 22 lamps (Philps TL-40W) were used for UV light sources, and the intensity was set by controlling 22 lamps. According to our investigations, the concentration of SOA with the strongest UV lights was more than three times higher than that without UV lights. As a result of the SOA formation, the concentration of NOx was decreased while the concentration of ozone was increased. We also found that the ratio of NOx and toluene affects the concentrations of SOA in the chamber experiments.AcknowledgmentsThis study was supported by the National Research Foundation of Korea (grant number NRF-2021R1C1C1013350).