bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of the Subantarctic Mode Water in the Southern Ocean
Authors: Hong Yu
Published: March 2024

Powerful westerlies in the Southern Ocean drive the Antarctic Circumpolar Current (ACC), the northward Ekman flow, and the associate upwelling of the Circumpolar Deep Water (CDW). The upwelled CDW is transported northward by the Ekman flow. Upon reaching the north side of the Subantarctic Front (SAF), these waters undergo intensive vertical mixing driven by cooling of the atmosphere in winter, forming the Subantarctic Mode Water (SAMW) with vertically homogenous properties. The SAMW is then transported eastward with the ACC and northward with the subtropical gyre, completing the ventilation of the Southern Hemisphere oceans. As a part of the upper limb of the Southern Ocean overturning circulation, the formation and transport of the SAMW play essential roles in the heat, freshwater, carbon, oxygen, and nutrient budgets both regionally and globally. Changes in its physical properties also provide good indications of global climate change. The SAMW has significant natural variability on different time scales, mainly regulated by factors such as sea surface buoyancy flux, the Ekman transport and pumping, and eddies. Under global warming, research has presented different conclusions regarding changes in the volume and properties of the SAMW, hindering our further understanding of its climate impacts.By analyzing gridded Argo observations in the past decades and future warming model simulation from the Coupled Model Intercomparison Project (CMIP), we found that the volume of the SAMW is generally decreasing. This volume decreasing is mainly determined by the change in surface buoyancy flux. The volume of the SAMW slowly increases after the radiative forcing stabilized in the future warming simulation. We also found there is an opposite change in volume between different density layers, representing changes in properties of the SAMW. The opposite volume change is mainly determined by the change in the depth and position of the winter deep mixed layer. Meanwhile, the observed average temperature and salinity of the SAMW in the South Indian Ocean are increasing. But the freshening in the formation area and the southward shift of the isopycnal surfaces weaken the trend of the average temperature and salinity increase of the SAMW. In future warming simulations, the cooling and freshening on the isopycnal surfaces cause the minimum warming and strong freshening in the depth of SAMW. These conclusions deepen our understanding of the evolution of the SAMW in the Southern Ocean and its underlying physical mechanisms, providing a new perspective on the climate response and impact of water masses in the Southern Ocean.
Building the software, data and training foundations to support Australia’s climate simulator (ACCESS-NRI)
Authors: Druken Kelsey , Heerdegen Aidan , Beucher Romain , Edberg Roger , Bateman Natalia , Allen Victoria , Carouge Claire , Dix Martin , Nettelbeck Heidi , Hogg Andy
Published: March 2024

ACCESS-NRI is a national research infrastructure (NRI) established to support the Australian Community Climate and Earth System Simulator, or ACCESS. The ACCESS suite of software and data outputs are essential tools used to simulate past and future climate, weather and Earth systems and to support research and decision making within Australia. ACCESS-NRI's mission is to build an open collaborative infrastructure that will accelerate research in Earth system, climate and weather modelling as well as enable new research not currently possible. The facility brings together skills in software development, high-performance computing, data management and analysis to enhance the ACCESS modelling framework, making it easier to use and lowering the barrier for innovation.   

To improve usability and uptake of this complex modelling framework, the software, data and training program is comprised of 3 teams that focus on providing open and transparent processes for the development, release, and user training of the ACCESS models, tools and data. This presentation will provide an overview of the program’s establishment over the first 18 months as a new facility. This includes enabling reproducible build and deployment workflows, supporting tools to analyse and evaluate model output, data management and development of training tools and materials. Core to all capabilities across the organisation is openness and community engagement in our open development and decision-making processes. This presentation will also discuss the critical infrastructure foundations we have built to support this engagement and advance the impact of ACCESS. 

ACCESS became a National Research Infrastructure (NRI) facility through funding from the Australian Government’s National Collaborative Research Infrastructure Strategy (NCRIS) Program and officially launched in June 2022. This facility is a major collaborative undertaking between the Bureau of Meteorology, CSIRO and five Australian universities, in collaboration with national and international partners. 
Assessing Sediment Delivery from Catchment Areas to Coastal Ecosystems in the Pacific Islands: A Study in an Urban Context
Authors: Jorquera Eliana , Rodriguez Jose Fernando , Saco Patricia Mabel , Quijano Baron Juan Pablo , Breda Angelo , Sandi Steven , Verdon-Kidd Danielle , Nelson Filomena
Published: March 2024

Coastal mangroves provide vital habitats for marine and coastal ecosystems while also stabilising coastlines, preventing erosion and mitigating the impact of storms. Sea-level rise poses a significant threat to these areas, causing submergence, vegetation changes, and hydrodynamic alterations. Sediment accretion can attenuate the effects of sea-level rise by promoting sedimentation. Mangroves trap sediments with their roots, which gradually create soil layers. The balance between soil accretion and sea-level rise will determine the mangrove's ability to adapt and survive. It is, therefore, crucial to determine the amount of water and sediments produced in the tributary catchment that reaches mangrove areas.Moata'a is an urban village on the Upolu Island of Samoa, comprising around 300 to 500 households. It is home to a mangrove wetland that has been negatively impacted by human activities such as urban expansion, uncontrolled extraction of natural resources, pollution, and modification of input flows and tidal regime. Furthermore, Moata'a is susceptible to extreme weather conditions such as tropical cyclones, floods, and droughts, which may worsen as a result of climate change.The amount of water and sediments that flow into the Moata'a mangrove area is influenced by the Vaisigano River. Moata'a is situated in the Vaisigano River's floodplain region, one of the primary rivers on Upolu Island. The Vaisigano River catchment is characterised by a hilly terrain covered with forests and a narrow coastline. During significant flooding events, water is transferred from the Vaisigano to the Moata'a catchment. Significant sediments can be discharged into the mangrove areas in these extreme circumstances.This contribution presents a hydro-sedimentological assessment of the Moata’a’s mangrove catchment. The Soil & Water Assessment Tool (SWAT) was used to quantify the amount of water and sediment generated in the Moata’a’s catchment and the water and sediments produced by the Vaisigano catchment that are transferred to Moata’a’s mangroves during extreme events.
Comprehensive Analysis of Ground-Level Ozone Pollution in Arizona: Source Attribution, Dynamics, and Cross-Border Transport
Authors: Guo Yafang , Arellano Avelino
Published: March 2024

Ground-level ozone (O3) pollution is a persistent environmental concern despite substantial reductions in anthropogenic emissions over the past decade. This study delves into the specific case of Arizona, United States, a region marked by elevated O3 concentrations and designated non-attainment areas by the U.S. Environmental Protection Agency. Additionally, we explore the contributions of distinct O3 sources to overall levels, employing a tagging technique within the WRF-Chem model and the MOZART gas chemistry mechanism. This methodology allows us to attribute the sources of nitrogen oxides (NOx), with a particular emphasis on contributions from anthropogenic, fire, and biogenic emissions. Furthermore, our investigation employs the model to trace the transport of O3 and its precursors (NO2, VOC) from surrounding states and Mexico, contributing valuable insights into the complex dynamics of O3 pollution in the region.
Antifeedant biomarkers in Cretaceous sediments from the North Sudetic Basin, Poland
Authors: Goryl Magdalena , Marynowski Leszek , Simoneit Bernd R.T.
Published: March 2024

The Late Cretaceous succession of siliciclastic sediment from the Czerna Formation in the North Sudetic Basin (SW Poland) consists of sandstones, dark grey mudstones and shales with coal intercalations. Samples of dark grey mudstone with lignite fragments from the inoperative sandstone quarry in Rakowice Małe, and samples of coals and siltstones from the sandstone quarry in Wartowice, were selected for gas chromatography-mass spectrometry analyses. All samples were thermally immature (the mean vitrinite reflectance (Rr) values did not exceed 0.45%).The samples contained phenolic abietans, including ferruginol and chamaecidin, which act as a defence mechanism against insect and microbial attack in coniferous trees (e.g., Gonzalez, 2015). Therefore, these compounds are widespread in extant coniferous trees (Simoneit et al., 2021) and can be identified in the geological record through their primary and diagenetic products. For instance, ferruginol (natural product), along with its derivatives: simonellite and retene, are present in the Cretaceous sedimentary rocks of the North Sudetic Basin. Another compound identified in the investigated samples is bergamotan. Perry et al. (2003) found that two derivatives of this compound were responsible for the insect antifeedant activity. Moreover, some of the identified compounds, such as chamazulene, are known in medical science for their anti-inflammatory properties (Safayhi et al., 1994).The presence of natural products with antifeedant activity against insects in Cretaceous samples suggests that plants had developed host defence mechanisms tens of millions of years ago. AcknowledgementsThe authors acknowledge financial support from the Polish National Science Centre (grant 2018/31/N/ST10/01646 to MG). ReferencesGonzalez, M.A., 2015. Aromatic abietane diterpenoids: Their biological activity and synthesis. Natural Product Reports 32, 684–704.Perry, N. B., Burgess, E. J., Foster, L. M., Gerard, P. J. (2003). Insect antifeedant sesquiterpene acetals from the liverwort Lepidolaena clavigera. Tetrahedron Letters 44(8), 1651–1653.Safayhi, H., Sabieraj, J., Sailer, E. R., Ammon, H. P. (1994). Chamazulene: An antioxidant-type inhibitor of leukotriene B4 formation. Planta Medica. 60 (5), 410–3. Simoneit, B. R. T., Rybicki, M., Goryl, M., Bucha, M., Otto, A., Marynowski, L. (2021). Monoterpenylabietenoids, novel biomarkers from extant and fossil Taxodioideae and rocks. Organic Geochemistry, 154, 104172.
The Northward Expansion of the Tibetan Plateau: Topographic Evidence from the Bogda Mountains—Junggar Basin Coupling system, Northwest China
Authors: Duan Mengyue , Neubauer Franz , Robl Jörg , Zhou Xiaohu , Liebl Moritz
Published: March 2024

Distinct Mountain–Basin coupling systems were formed during the expansion of the Tibetan Plateau into the surrounding low elevation regions in the north, northeast and east. In this study, we focus on the topographic features of the Bogda Mountains–Southern Junggar Basin coupling system on the north of the Tibeau Plateau, which influenced by the N-S orthogonal shortening caused by the uplift of the Tibetan Plateau and northward propagation of deformation away from the India-Asia collision zone. We mainly quantify the influence of uplift of the Tibetan Plateau on the formation of the Bogda Mountains–Junggar Basin coupling system by fluvial geomorphologic analysis based on the digital elevation model analysis and the optically stimulated luminescence (OSL) dating on the Dalongkou river terraces on the northern slope of Bogda Mountains. Together, these morphological analyses show that the high normalized steepness index (ksn) and knickpoints mainly distributed in the western Bogda Mountains. The normalized steepness index (ksn) gradually decreased from west to east, which indicated that the tectonic activity of the western Bogda Mountains is higher. The compiled low-temperature thermochronology data of the Bogda Mountains show a younging trend from west to east, which indicates that the western Bogda uplift started earlier than in eastern Bogda. The difference of the χ values on both sides of the Bogda Mountains is similar, which means the drainage divide of the Bogda Mountains is stable. There are five river terraces distributed on both side of the Dalongkou River. The optically stimulated luminescence (OSL) dating results show that the ages of the T2 river terrace, T3 river terrace, T4 river terrace of the Dalongkou river are 6.2±1.3 ka, 13.1±1.7 ka, and 14.2±2.5 ka, respectively. The incision rate of the Dalongkou river increases upstream from ~1.22 mm/yr close to the southern Junggar Basin, to ~2.1 mm/yr, and to ~6.33 mm/yr in front of the higher Bogda Mountains, which means that the uplift rate of the Dalongkou river increases upstream. We propose a model of upbending of central Bogda Mts. by ongoing Holocene folding, with an inflection point close to the southern boundary to the Junggar Basin. By comparing the geomorphological features of the Bogda Mountains with the North Tianshan Mountains, we conclude that the tectonic uplift intensity gradually decreased from the North Tianshan Mountains to the Bogda Mountain, as well as the gradual accelerated uplift rate of the Bogda Mountains, are influenced by the N-S orthogonal shortening caused by the uplift of the Tibetan Plateau, which is gradually decreasing from west to east.
Evaluation of the River Discharge Considering Interaction of Surface water and Groundwater in the Yeongsan-Seomjin River in the Republic of Korea Using DWAT (Dynamic Water Resources Assessment Tool, DWAT)
Authors: Jang Cheolhee , Kim Deokhwan , Choi Jeonghyeon , Shin Hyoungsub , Kim Hyeonjun
Published: March 2024

The availability of water resources generally refers to the volume of total water resources on the surface, sub-surface, and soil. For a precise assessment of the availability of water resources, it is necessary to secure the accuracy of meteorological forecasts such as precipitation and temperature forecasting and to be able to accurately evaluate the volume of invisible water resources under the surface. Metropolitan areas around large rivers can use water stably even in the event of a drought, but the upstream areas with small and medium-sized rivers are vulnerable to water supply stability in drought season. Therefore, highly reliable evaluation and prediction of river discharge is necessary to prepare comprehensive solutions such as efficient operation of water supply facilities and optimal use of available water resources during drought season.  In this study, river discharge was evaluated for 20-16 standard basins in the Yeongsan-Seomjin river basins, respectively, among major river basins in the republic of Korea. The Dynamic Water resources Assessment Tool (DWAT) was used as a assessment model. DWAT is a water resources assessment tool that can be used free of charge worldwide and can be applied to small and medium-sized river basins for water resource planning and management that considers surface water as well as groundwater and water usage for various purposes. The calibration period was set from 2012 to 2019, and the validation period was set from 2020 to 2021. In addition, simulation accuracy was calculated through a 1:1 comparison of observed and simulated discharge data based on the calibration point, and model efficiency (Nash Sutcliffe Efficiency, NSE)
Impacts of projected Arctic sea ice loss on daily weather patterns over North America
Authors: Gervais Melissa , Sun Lantao , Deser Clara
Published: March 2024

Future Arctic sea ice loss has a known impact on Arctic Amplification (AA) and mean atmospheric circulation. Furthermore, several studies have shown it leads to a decreased variance in temperature over North America. In this study, we analyze results from two fully-coupled Community Earth System Model (CESM) Whole Atmosphere Community Climate Model (WACCM4) simulations with sea ice nudged to either the ensemble mean of WACCM historical runs averaged over the 1980-1999 period for the control (CTL) or projected RCP8.5 values over the 2080-2099 period for the experiment (EXP). Dominant large-scale meteorological patterns (LSMPs) are then identified using self-organizing maps applied to winter daily 500 hPa geopotential height anomalies (𝑍′500) over North America. We investigate how sea ice loss (EXP-CTL) impacts the frequency of these LSMPs and, through composite analysis, the sensible weather associated with them. We find differences in LSMP frequency but no change in residency time indicating there is no stagnation of the flow with sea ice loss. Sea ice loss also acts to de-amplify and/or shift the 𝑍′500 that characterize these LSMPs and their associated anomalies in potential temperature  at 850hPa. Impacts on precipitation anomalies are more localized and consistent with changes in anomalous sea level pressure. With this LSMP framework we provide new mechanistic insights,  demonstrating a role for thermodynamic, dynamic and diabatic processes in sea ice impacts on atmospheric variability. Understanding these processes from a synoptic perspective is critical as some LSMPs play an outsized role in producing the mean response to Arctic sea ice loss.
Inversion tectonics and dual decollements in southwestern Taiwan: implication from a dense seismic array
Authors: Wang Wei-Hau , Lin Yi-Shen , Huang Wei-Cheng , Wen Strong
Published: March 2024

We employed dense seismic arrays to reveal the seismogenic zones beneath the foreland basin and the foothills in southwestern Taiwan. We used EqTransformer to pick earthquakes and P and S wave arrival time, GaMMA to associate earthquakes, and NonLinLoc to locate the earthquakes. Our results show that the thin-skinned thrust belts were mostly locked above a shallow decollement at a depth of ca. 6 km. Below it, a foreland-dipping seismogenic belt extends from the base of the shallow decollement to a depth of about 15 km, the deep decollement, beneath the coastal plain. We interpret this westward-dipping seismogenic belt as a passive roof duplex by inversion of the pre-existing graben-and-horst structure sliding along a ductile shear zone at a depth of 15 km during the ongoing orogeny.
Two extremes: Investigating the impact of the co-occurrence of medicanes and marine heatwaves in the Mediterranean Sea.
Authors: Uba Kenechukwu , Hamdeno Manal , Barth Alexander , Alvera-Azcárate Aida
Published: March 2024

The oceans are steadily warming, which affects global weather and climate and leads to an increase in extreme events such as storms, hurricanes and marine heatwaves (MHWs). Future warming scenarios predict an increase in the frequency and intensity of such events. In the Mediterranean region, both extratropical cyclones and occasional Mediterranean hurricanes (medicanes) occur, causing considerable damage to infrastructure and major socio-economic losses in coastal regions. Using ERA-5 atmospheric reanalysis data and satellite-derived sea surface temperatures (SST), this study looks at medicanes that occurred between 2011 and 2023 and examines their characteristics and impacts on the water column. The interaction with simultaneous MHWs in the Mediterranean is also investigated. A total of 15 medicanes occurred during the study period. Of these, 5 occurred in the western Mediterranean (WMed), mainly in November; 9 in the central Mediterranean and Ionian (CMed) between September and December, two of which terminated in the eastern basin; and 1 event was localised entirely in the eastern Mediterranean (EMed) in October. During the study period, 2014 recorded the highest number of medicanes with three events. One event, Ilona, occurred in January in the WMed, while the other two events, Qendresa and Xandra, occurred in November in the CMed and WMed respectively. Two events took place in both 2020 and 2021. In 2020, both Ianos in September and Elaina in December were in the CMed. In 2021, the CMed and WMed witnessed the passage of Apollo in October and Blas in November respectively. In the 15 medicanes, the mean sea level pressure (MSLP) was between 988 and 1005 hPa, while the wind speeds (Ws) were between 17 and 23 m/s. Among the events, Ilona in January 2014 had the lowest MSLP and highest Ws and the lowest associated MSLP anomaly. Of the 15 events, 11 (73%) were associated with anomalously high sea surface temperatures (SSTA) and five of these SSTAs were defined as MHW events. Moreover, the high SST anomalies were observed three or more days before the onset of these medicanes, which may have contributed to the intensification of the passing storms and amplified their impact through air-sea heat exchange. In turn, the medicanes were also observed to influence the MHWs, as the heat released from the ocean during the medicanes prevented the MHWs from deepening beyond the surface layer, demonstrating a dynamic interplay between these events. In summary, as the oceans warm, medicanes and MHWs in the Mediterranean increase, with complex interactions determining their behavior and impacts. Understanding these dynamics is crucial for predicting and mitigating the impacts of these events on marine ecosystems and coastal regions. 
Tritium Leakage Traces the Path of Cesium from Fukushima Daiichi Nuclear Power Plant into the Ocean
Authors: Onda Yuichi , Sato Hikaru , Tsumune Daisuke
Published: March 2024

Reducing the release of radionuclides into the environment is crucial for decommissioning nuclear facilities and post-accident remediation. After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, a seawall was constructed to minimize the direct discharge of Cs-137-contaminated groundwater into the ocean. Despite this measure, unexplained seasonal variations in Cs-137 emissions continued. Notably, between 2013 and 2014, groundwater leaks from treated water storage tanks at the site led to detectable levels of tritium (H-3) in the groundwater moving downslope from the plant. Our study, conducted over 2015-2021, utilizes a watershed hydrologic tracer approach to identify the marine sources of Cs-137 and explore the underlying causes of its seasonal fluctuation.We analyzed H-3 in FDNPP groundwater and drainage channel K, known for high Cs-137 concentrations. By correlating this data with Cs-137 levels and runoff in the channel, we deduced the proportion of surface to total flow, identifying the main sources of Cs-137 and its seasonal variability. The surface flow, indicated by H-3 presence and further subdivided by effective rainfall analysis, revealed that the flow through the plant buildings was heavily contaminated with Cs-137, constituting the primary runoff source. We found that Cs-137 concentrations in basal flow are influenced by temperature, while those in surface flow respond to rainfall.These insights are crucial for effective cleanup strategies at FDNPP and demonstrate the broader applicability of using leakage H-3 as a tracer to identify sources of radioactive and chemical pollutants from terrestrial to marine environments in similar scenarios.
Ninety years of shoreline change at Narrabeen Beach (Australia) from sub-daily to decadal time scales
Authors: Harley Mitchell , Ibaceta Raimundo , Splinter Kristen , Turner Ian
Published: March 2024

Narrabeen Beach is 3.6 km-long embayed sandy beach located in southeast Australia on the northern beaches of Sydney. It is well known in the coastal research community for its long-term beach monitoring program, that was commenced in 1976 by Prof. Andy Short and has continued uninterrupted until the present day. This program has led to a number of groundbreaking research advances, including the Wright and Short morphodynamic beach state model, embayed beach rotation and links to climate cycles like the El Niño/Southern Oscillation.This presentation will present a significant extension of this monitoring program through the inclusion of advanced shoreline monitoring techniques. These techniques include: historical aerial photographs, airborne and fixed Lidar, UAV, satellite-derived shorelines (CoastSat), Argus coastal imaging and CoastSnap citizen science. This large dataset (comprising over 1 million data points) enables an unprecedented look at shoreline change in dynamic, wave-dominated environments on time scales from sub-daily to decadal. The talk will showcase new research derived from this dataset, including data-driven forecast models of shoreline erosion and insights on long-term coastal change. Finally, links to accessing this open-source dataset will be described.
Bipolar ice core constraints on the variability of the Brewer-Dobson Circulation during climate transitions
Authors: Geng Lei , Jiang Zhuang , Alexander Becky
Published: March 2024

The Brewer-Dobson circulation is the global atmospheric overturning circulation and regulates global mass and energy redistributions in the stratosphere as well as mass exchange between the troposphere and the stratosphere. Through transporting O3 to the troposphere and redistributing O3 in the stratosphere that influence surface UV-B radiation, the Brewer-Dobson circulation also plays an critical role in atmospheric oxidation capacity which matters for air quality, greenhouse gas removal and climate change. While many studies have assessed changes in the Brewer-Dobson circulation in the past few decades and in the future in response to greenhouse gas warming, that how Brewer-Dobson circulation has changed in the past climate is poorly constrained and limited modelling studies reached opposite results on the strength of the Brewer-Dobson circulation in the last glacial maximum (LGM). Atmospheric nitrate O-17 excess signal is sensitive to O3 abundance, and the latter is influenced by the strength of the Brewer-Dobson circulation especially during climate transitions (e.g., the glacial-interglacial cycle and the abrupt climate events). By comparing the nitrate O-17 excess records from the GISP2 and WAIS divide ice cores, we find a coherent changes in the O-17 excess signal from the LGM to the Holocene, suggesting a stronger Brewer-Dobson circulation in the LGM. In addition, during abrupt climate changes (i.e., the D-O events in Greenland and the corresponding AIM events in Antarctica), there is an apparent difference in the changes of O-17 excess in response to temperature in Greenland and Antarctica, a result implies that the Brewer-Dobson circulation should be enhanced when Greenland cools. These results are consistent with earlier model studies, but are in conflict with recent model work which predicts a weakened Brewer-Dobson circulation in the LGM. Specific mechanisms driving the response of the Brewer-Dobson circulation to past climate changes remains to be explored.
Optimizing rapid access englacial sampling location to date deep radiostratigraphy for old ice
Authors: Singh Shivangini , Young Duncan , Yan Shuai , Ng Gregory , Buhl Dillon , Vega Gonzalez Alejandra , Kerr Megan , Greenbaum Jamin , Kempf Scott , Blankenship Donald
Published: March 2024

The Center for Oldest Ice Exploration (COLDEX) aims to unearth a stratigraphically intact ice core record going back to 1.5 million years. The target area is the corridor between South Pole and the southern flank of Dome A. While our current survey has yielded dated stratigraphy extending to 93.9 thousand years ago across the region, a significant portion of the stratigraphy remains undated. Our approach has involved leveraging englacial connections with existing ice cores and dust loggers, yet much of the stratigraphy awaits dating. Rapid ice access tools are capable of sampling the ice sheet using far fewer resources as compared to conventional drilling. By optimizing the site for such sampling, we can preemptively maximize the information that can be extracted eventually.Our study’s objective in selecting a rapid ice access site is twofold: firstly, to maximize the age-depth scale extraction by dating the hitherto undateable deeper isochrones, and secondly, to strategically sample the pervasive basal layer in the survey region to understand its role in preserving old ice. To achieve an optimal age-depth scale extraction, we aim to target sites containing a larger portion of undated stratigraphy while maintaining the optimum resolution to understand ice age dust cycles. For instance, Ice Diver, a melt probe by COLDEX, houses an optical dust logger capable of counting ice age dust cycles.Previous research (e.g., Chung et al., 2023) indicates that a basal layer identified through radar sounding may exhibit a distinct flow regime compared to the stratigraphic portion of the ice sheet column. Accessing this layer in advance could provide insights into the interface between the echo-free zone and stratigraphic ice, thereby refining our understanding of current ice sheet models and how to exploit them in the pursuit of old ice. An ideal access site would facilitate quick sampling without requiring deep drilling to reach the basal layer. Our aim is to reconcile these methodologies by identifying the most suitable site(s) for deploying such probes or drills.
On the Combination of Physical Parameterization Schemes for Tropical Cyclone Track and Intensity Forecasts in the Context of Uncertainty
Authors: Wang Xuan , Tan Zhe-Min
Published: March 2024

The selection of physical parameterization schemes for tropical cyclone (TC) forecasts has required a substantial amount of effort. In general, the evaluation of physical parameterization schemes and their combined performance was based solely on the deterministic forecast, which had inherent limitations in representing the overall performance of physical parameterization schemes due to the model uncertainty. This study introduces an uncertainty-informed framework of evaluating and selecting the combination of physical parameterization schemes for TC forecasts, based on the ensemble forecast that could include the model uncertainty roles. The performance ranking of the scheme combination based on the ensemble mean error is found to be distinct from that based on the deterministic forecast error. Moreover, differences in both ensemble mean errors and ensemble spreads for various scheme combinations highlight the importance of considering two metrics concurrently, i.e., via the quality of the forecast distribution as a whole, to assess the forecast performance. Consequently, the ensemble Continuous Ranked Probability Score (eCRPS) is used to quantify the performance of the scheme combinations, and it is demonstrated that the performance is more comprehensive than that in the deterministic context. Finally, the well-performed scheme combination for the forecasts of six intense TCs is chosen from the evaluated schemes in the context of model uncertainty, based on the overall quality of TC track and intensity forecast distributions.
Overview and Outcome of the NASA Marine Oil Spill Thickness (MOST) Project
Authors: Jones Cathleen , Monaldo Francis , DeChamps Benjamin , Di Pinto Lisa , Garcia-Pineda Oscar , Graettinger George , Helfrich Sean , Holt Benjamin , Johansson Malin , Quigley Cornelius , Ramirez Ellen , Staples Gordon , Tulis Dana
Published: March 2024

In 2018, NASA funded a project to develop and mature automated oil spill detection and thickness estimates from synthetic aperture radar (SAR) and optical imagery, based on focused field testing combined with in situ oil sampling and airborne imaging with the UAVSAR L-band SAR.  The goal was to implement these new algorithms and databases in a semi-automatic system that NOAA uses operationally to detect and assess oil spills and post-storm offshore damage and debris.  The study's field validation site was the Coal Oil Point seep field, an area of natural seep activity located in the Santa Barbara channel, California, which leaks approximately 100 barrels of crude oil per day.  There were three campaigns to collect calibration/validation data, in May 2021, October 2021, and June 2022, during which UAVSAR overflew boat crews collecting optical images from a drone and some water samples for thickness and viscosity analysis.  The data was combined with available satellite SAR and optical imagery collected around the same time and used to develop an algorithm for classifying oil by relative thickness based upon contrast with clean ocean.  One algorithm is tailored for Sentinel-1 data and uses Machine Learning (ML) methods, and the other is an analytical analysis that can be applied to any radar frequency's data.  The data acquired in June 2022 has been used additionally to evaluate differentiation of mineral oil slicks from low wind radar-dark areas using a series of rapid repeat SAR images. In this talk, the study, data collections, and developed algorithms and methods will be presented.
Estimating Biomass in the Lithosphere: A Machine Learning Approach
Authors: Zhao Wenyu , Zhangzhou Johnny
Published: March 2024

Research on sampling and analysis of fluids and rocks within both continental and oceanic crusts has revealed a significant portion of Earth's prokaryotic biomass residing in the rock-hosted biosphere, extending to depths of several kilometers. This deep subsurface life within the lithosphere may host a substantial amount of Earth's biomass. However, more constrained estimates of this biomass are still lacking. In this study, we first determine the habitable volume of the lithospheric biosphere and then estimate its potential biomass. Temperature, a critical factor influencing the limits of life, is considered the primary focus in this context. We employ a machine learning approach to estimate the habitable volume of the lithosphere above the 122°C isotherm, which is considered the upper limit for prokaryotic life. Our methodology involves selecting a range of geophysical and geological features that are thought to impact geothermal gradients. These include Moho depth, lithosphere-asthenosphere boundary (LAB) depth, topography, susceptibility, tectonic units, gravity mean curvature, vertical magnetic field, and distances to ridges, trenches, transform faults, young rifts, and volcanoes, as well as P-wave and S-wave velocities in the crust. We used a Gradient Boosted Regression Tree algorithm to develop two models correlating geothermal gradients in continental and oceanic settings with these geophysical and geological features. The models were applied to a binned grid with a 0.5° x 0.5° resolution, enabling the estimation of the depth to the 122°C isotherm for each grid based on the machine learning model's predictions of geothermal gradients. Our results reveal substantial habitable volumes within the lithosphere. The habitable volume in the continental crust may account for about 7% of the total crustal volume, while in the oceanic crust, it could be around 5%. Given the cell density range of 102 to 106 cells per gram in oceanic rocks and 102 to 104 cells per gram in continental rocks, along with an estimated carbon mass of 2x10-14 grams per cell, the lithospheric biomass is estimated to be between 0.008 and 33.2 Gt Carbon. For context, the biomass found in plants and marine microbes is estimated to be around 450 Gt Carbon and 2.9 Gt Carbon, respectively.
Mid-latitude Electric Field Response during Isolated Substorms: Effects of SCW Location and Shielding
Authors: Hayashi Moe , Yoshikawa Akimasa , Fujimoto Akiko
Published: March 2024

The substorm current wedge (SCW) characterizes the current system during substorms. The high-latitude electric field associated with the SCW penetrates toward mid- and low-latitudes. Various case studies have reported that the penetration electric field becomes stronger with the region-1 (R1) sense SCW, while the region-2 (R2) sense SCW shields the electric field. However, the statistical properties of the penetration electric field remain unclear. Moreover, the detailed relationship between the SCW's location and the electric field has been seldom examined. In this study, using substorms that occurred from 2010 to 2013, we evaluated the effects of shielding and statistically investigated its impact on the mid-latitude electric field using the following methods. We determined the temporal development of the SCW structure from the north-south and east-west components of the ground magnetic field and evaluated the effect of shielding, based on the magnitude of the R1/R2 SCW by AMPARE. We then analyzed the relation between these and the direction and magnitude of the electric field from Kyushu University’s FM-CW radar at midlatitude. The results show that, when the R1 SCW is more dominant, a westward electric field is observed in the center of the SCW and an eastward electric field is observed on the outside. The magnitude of those electric fields depends on the scale of the substorms. When the R2 SCW is comparable to the R1 SCW, these electric fields are shielded or overshielded, resulting in a smaller magnitude or opposite direction of the electric field. These findings suggest that the strength of the R2 SCW and the location of the SCW are the major contributors to the penetrating electric field.
Using the LIMS with Lithology (LILY) Database to Probe IODP Density, Porosity, and P-Wave Velocity Data
Authors: Acton Gary , Childress Laurel , Percuoco Vincent
Published: March 2024

We use the LIMS With LithologY (LILY) database compiled by Childress et al. (https://zenodo.org/records/8408297) to examine relationships between physical properties and the lithology of marine drill cores collected by the International Ocean Discovery Program (IODP) and its precursor program between 2009 and 2019. Within LILY, lithologic information such as the principal lithologic name and the major and minor lithologic modifiers, along with other metadata, have been added to each of the more than 34 million observations from the standard data available in IODP’s LIMS Database, which is accessible through the LIMS Online Reports (LORE) portal (web.iodp.tamu.edu/LORE/). The ability to compare and combine descriptive lithologic information across expeditions and to integrate these descriptions with multisensor track and discrete sample measurements allows for a wealth of scientific investigation not possible under the original data structure. One of the obvious values of LILY is the ability to characterize the basic physical, chemical, and magnetic properties of different lithologies from a very large number of observations. As an example of this, we compute grain densities for all available lithologies using the Moisture and Density (MAD) density data from over 24,000 measurements. Once the grain densities are known, then the bulk densities can be used to determine porosity. This is important because besides the over 24,000 MAD bulk densities, there are 3.7 million gamma ray attenuation (GRA) bulk densities measured by the Whole Round Multi-Sensor Logger (WRMSL). Comparison of MAD and GRA bulk densities permits biases in the GRA density dataset to be corrected. These corrected GRA bulk densities are then used to compute a new high-resolution porosity dataset (https://zenodo.org/records/10001855). We further merge this large bulk density and porosity dataset with the P-wave velocity data from a P-wave Logger that is part of WRMSL, a P-wave Caliper, and P-wave Bayonets to characterize lithologic-dependent relationships between density, porosity, and P-wave velocity.
Permafrost and Climate Change: Carbon Cycle Feedbacks From the Warming Arctic
Authors: Schuur Edward (Ted) ,   Permafrost Carbon Network
Published: March 2024

Rapid Arctic environmental change affects the entire Earth system as thawing permafrost ecosystems release greenhouse gases to the atmosphere. The permafrost soil carbon pool contains three times as much carbon as in the atmosphere, with 1440-1600 Pg C known, and another ~960 Pg C in other deep sediments and subsea. The permafrost region contains 50% of the soil carbon found in all other Earth’s biomes (0-3m) in only 15% of the global soil area, and this is likely a minimum. Understanding how much permafrost carbon will be released, over what time frame, and what the relative emissions of carbon dioxide and methane will be is key for understanding the impact on global climate. In addition, the response of vegetation in a warming climate has the potential to offset at least some of the accelerating feedback to the climate from permafrost carbon. Temperature, organic carbon, and ground ice are key regulators for determining the impact of permafrost ecosystems on the global carbon cycle. Together, these encompass services of permafrost relevant to global society as well as to the people living in the region and help to determine the landscape-level response of this region to a changing climate.Nine scenarios of cumulative net carbon dioxide and methane emissions over this century were developed to encompass the full range permafrost carbon emissions projections linked to global and Arctic warming. These cumulative permafrost carbon emission scenarios range from 55 to 230 Pg C (C-CO2-equivalent units) and represent future Arctic carbon emissions that can be compared relative to national-level emissions that are the focus of climate change mitigation conversations. This helps to place these scenarios alongside policy conversations aimed at reducing national greenhouse gas emissions. Many of the modeled climate change trajectories where mitigation of human carbon emissions leads to various global temperature targets do not necessarily contain all of the detailed information for the Arctic carbon cycle as compared to the projections reviewed here. In this way, it can be helpful to view potential Arctic carbon emissions as the equivalent of an additional large industrialized nation of carbon emissions that must be accounted for in order to reach specific temperature targets. Arctic carbon emissions accelerate climate change, adding 10-15% to future fossil fuel emissions, potentially decreasing the land carbon sink by 33-50%. Accounting for these additional greenhouse gas emissions will help to slow climate change and potentially avoid Arctic carbon cycle surprises from abrupt thaw and other threshold events.  
Research on new methods and equipment for seismological monitoring of glaciers on the Qinghai-Tibet Plateau
Authors: Gamez Richard , Zou Lei
Published: March 2024

Solid Earth Sciences：SE07 Faults and Earthquakes: Networks, Precursors, Monitoring Systems and Numerical Modelling TechniquesResearch on new methods and equipment for seismological monitoring of glaciers on the Qinghai-Tibet PlateauLei Zou1, Richard Games2, ……1 SmartSolo Inc., China2 SmartSolo Inc., Huston, USAAbstract: Glacier seismology combines the advantages of glaciology and seismology to form a young interdisciplinary subject. Icequakes are vibrations produced during the movement and breakup of glaciers, ranging from small squeaks to sudden ruptures or slides equivalent to earthquakes (MW7). According to the location and mechanism of icequake occurrence, icequakes can be divided into five types: surface fissures, stick-slip movement, iceberg calving, subglacial flow, and hydraulic fracturing. In addition to traditional seismological methods, icequake research can also be conducted using multidisciplinary methods such as GPS, numerical simulation, and glacier physical properties. Icequake research can further explore the occurrence process and risk assessment of ice avalanches. We review advances in glacier seismology.Our users use SmartSolo scientific instruments to successfully analyze ice avalanche events through vibration signals by observing multi-parameter glacier environment and climate changes, combined with seismological observation instruments. Provide a new and effective monitoring method for glacier seismic monitoring. It enriches the process observation and risk assessment methods of ice avalanche occurrence, and the combination of multiple parameters further improves the accuracy and effectiveness of ice avalanche event monitoring.
The exceedance of physiologically relevant thresholds in South Asia
Authors: Monteiro Joy , Justine Jenix , Shah Hardik , Rao Neethi
Published: March 2024

Since the pioneering work in the early 2000s, there has been interest in the climate science community in using the compounding effects of heat and humidity (in the form of wet-bulb temperatures or other meteorological indices such as heat index) to understand health risks due to thermal stress on humans. For instance it has been suggested that the combination of high heat and humidity was responsible for the high mortality observed during the 2015 heatwaves in South Asia. However, assessing health impacts of temperature and humidity is challenging in South Asia since the health data required for epidemiological work is rarely available or reliable for robust analyses.Using quality-controlled surface observations, we show that the humidity (or equivalently, wet-bulb temperatures) was in fact lower during most high impact heatwaves in South Asia -- the daily maximum was very close to its monthly mean value whereas the daily minimum dropped to much lower values. We show that this is due to a deeper boundary layer which dilutes the near-surface water vapour concentrations. Therefore, our analysis suggests that one-dimensional indices such as wet-bulb temperature may not be accurate in predicting health risks across the wide variety of meteorological conditions that South Asia experiences.Using recent experimental results that demonstrate that hazardous conditions can occur at lower humidity values, we show that thresholds derived from these experiments produce a more realistic spatial and temporal distribution of hazardous conditions in South Asia as compared to wet-bulb temperatures alone. Furthermore, we show that hazardous exposure during the day extends to times not usually considered hazardous in public health messaging. Our results suggest that physiological thresholds provide a complementary way to assess health risk due to heat along with epidemiological regression studies.