bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical analysis of ion composition and effects on EMIC waves in the outer magnetosphere
Authors: Lee Justin , Toledo-Redondo Sergio , Cohen Ian , Turner Drew , Vines Sarah , Allen Robert
Published: March 2022

Ionospheric-originating cold ions are difficult to measure throughout Earth's magnetosphere due to spacecraft charging limiting our ability to measure this low energy population, thus complicating investigations into how these cold ions participate in the growth of electromagnetic ion cyclotron (EMIC) waves. While these cold ion populations pose measurement challenges for most missions, recent event studies have shown that, at times, the Magnetospheric Multiscale (MMS) mission is capable of directly measuring both the low-energy cold populations as well as the hot ion composition, enabling improved understanding of EMIC wave generation, propagation, and wave polarization properties [1, 2, 3, 4]. These studies demonstrated the utility of considering the full ion composition for improving our understanding of different aspects of EMIC waves in the outer magnetosphere. We applied our experience analyzing the combined ion composition and EMIC wave data from event studies and conducted a statistical analysis of MMS datasets during the Prime Mission dayside intervals, with plans to expand the analysis to later mission phases and other magnetospheric regions. Out of approximately 6000 dayside wave intervals identified, around 25% of the intervals also contained simultaneous measurements of the cold ion composition needed to conduct more accurate modeling of linear wave growth in the outer magnetosphere, where the free energy source of EMIC waves may also be modulated by solar wind pressure pulses. This paper will discuss observations and progress on the statistical analysis and possible implications for studies on inner magnetospheric EMIC waves.

References
1.    Vines, S. K., Allen, R. C., Anderson, B. J., Engebretson, M. J., Fuselier, S. A., Russell, C. T., et al. (2019). EMIC Waves in the Outer Magnetosphere: Observations of an Off-Equator Source Region. Geophys. Res. Lett. 46, 5707–5716. doi:10.1029/2019GL082152
2.    Lee, J. H., Turner, D. L., Toledo-Redondo, S., Vines, S. K., Allen, R. C., Fuselier, S. A., et al. (2019). MMS Measurements and Modeling of peculiar Electromagnetic Ion Cyclotron Waves. Geophys. Res. Lett. 46, 11622–11631. doi:10.1029/2019GL085182
3.    Lee, J. H., Turner, D. L., Vines, S. K., Allen, R. C., Toledo-Redondo, S., Bingham, S. T., et al. (2021). Application of Cold and Hot Plasma Composition Measurements to Investigate Impacts on Dusk-Side Electromagnetic Ion Cyclotron Waves. J. Geophys. Res. Space Phys. 126, e2020JA028650. doi:10.1029/2020JA028650
4.    Toledo-Redondo, S., Lee, J. H., Vines, S. K., Turner, D. L., Allen, R. C., André, M., et al. (2021). Kinetic Interaction of Cold and Hot Protons with an Oblique EMIC Wave Near the Dayside Reconnecting Magnetopause. Geophys. Res. Lett. 48, e2021GL092376. doi:10.1029/2021GL092376
Causes of overgrazing in Inner Mongolian grasslands: Searching for deep leverage points of intervention
Authors: Fang Xuening , Wu Jianguo
Published: March 2022

The legendary Mongolian Plateau has faced increasing environmental challenges associated with overgrazing during recent decades, and achieving a sustainability transition for this region needs herders’ participation.  However, why herders let grasslands be overgrazed even after property rights were privatized – “the tragedy of privatization” – remains unclear.  This study aimed to understand the underlying causes of overgrazing by examining the livestock decision-making processes by herders.  Specifically, we investigated herders’ livestock management goals, perceptions of herder-grassland systems, and livestock management strategies by semi-structured interviews in Xilingol, Inner Mongolia.  We found: (1) Herders generally recognized grassland degradation with a decreasing plant species richness and vegetation heigh;  (2) Nearly half of herders were unsatisfied with their current quality of life, especially in terms of income, food security, energy security, and clean water;  (3) Herders recognized the economic benefits and food provisioning services of the grassland, but not overgrazing as an important cause of grassland degradation; (4) Without heavy economic pressures, herders were willing to protect their own grasslands, but over-exploited leased grasslands;  (5) Herders tried to keep a high and stable level of livestock numbers without being able to anticipate climatic and economic fluctuations; and (6) The government’s Forage-Livestock Balance policy was widely resisted by herders.  We conclude that herders’ increasing aspirations for higher living standards, misperceptions about key drivers of grassland degradation, decoupling of herders’ income from grasslands, inability to cope with drought, and ineffective policies together constitute the underlying causes for overgrazing.  Future grassland policies should focus more on the “deep” leverage points of intervention, such as reducing poverty and economic inequality, improving the grassland property system, reconnecting grassland conditions to herder’s wellbeing, and equipping herders with much needed scientific knowledge to manage grasslands in a way that is both economically profitable and ecologically sustainable. 
Analysis of water hyacinth (Eichhornia crassipes) infestation in a river branch using Sentinel-2 satellite data
Authors: P. de Lima Isabel , Gerardo Romeu
Published: March 2022

The worldwide spread of invasive aquatic plants in freshwater environments often leads to serious environmental (including ecological and socio-economic) problems, which requires a deeper knowledge of the extent of infestations (in time and space), and the abundance and propagation rates of aquatic weeds in invaded water systems. In particular, water hyacinth (Eichhornia crassipes) has become a threat to many aquatic environments: by presenting a rapid reproductive capacity; water hyacinth outcompetes other aquatic plant species, forming dense free-floating mats, which in many instances completely cover fresh-water surfaces. The infestation leads to several impacts that are hazardous to aquatic systems, disables human uses of surface waters, and affects hydraulic infrastructures (e.g., waterways, pumping stations). In general, the water hyacinth’s fast growth rate is explained, to a large extent, by eutrophication in water bodies.

This study explores the use of remote sensing tools to characterize the presence of water hyacinth in a river environment, aiming at new insights into the detection, observation, and mapping of this invasive plant using multispectral based vegetation indices and water indices, such as NDVI and NDWI. The study focuses on a small watercourse located in the downstream part of the Mondego River Valley, in Portugal. Multi-temporal data were acquired by multispectral satellite Sentinel-2; the data spatial resolution is 10 m. Results from this study show that the new generation sensors’ data have the potential to better detect the spatial distribution of invasive plant species and temporal dynamic changes in their incursion level, compared to data collected during (traditional) time costly ground-based surveys. The remote sensing approach provides a baseline to inform planners and decision-makers and a framework for developing water hyacinth management and important eradication strategies.
Simulating Pleistocene climate effect on archaic human interbreeding
Authors: Ruan Jiaoyang , Timmermann Axel , Yun Kyung-Sook , Zeller Elke , Lemmon Danielle
Published: March 2022

Genomic data document multiple episodes of interbreeding among Neanderthals, Denisovans and Homo sapiens. When, where and how often the interbreeding between these hominin populations took place remains unclear. Here, we study the Neanderthal-Denisovan admixture during the past 400 thousand years using a novel habitat model that integrates extensive fossil, archeological, and genetic data with unprecedented transient Coupled General Circulation Model simulations of global climate and vegetation. Our Pleistocene hindcast of habitat suitability reveals pronounced climate-driven zonal shifts in the main overlap region of Denisovans and Neanderthals in central Eurasia. These shifts, which influenced timing and intensity of potential interbreeding events, can be attributed to the response of climate and vegetation to past variations in atmospheric CO2 and northern hemisphere ice-sheet volume. Therefore glacial/interglacial climate swings likely played an important role in archaic human gene flow and genetic diversification.
Splash dynamics of aeolian sediment transport
Authors: Kelley Madeline , Swann Christy , Schmeeckle Mark , Walker Ian
Published: March 2022

The aeolian saltation cloud is controlled by the rebound and splash of particles upon impact with the bed. The vertical particle concentration profile and the subsequent reduction in near-bed fluid velocity are intricately linked. However, conceptual and numerical models of the fundamental interactions between the impacting and rebounding particles are often difficult to validate. Currently, sensor capabilities are limited in measuring particle-bed interactions directly. We present a series of wind tunnel experiments using Particle Tracking and Imaging Velocimetry (PTV/PIV) to overcome these measurement limitations by unobtrusively measuring particles in transport under various flow and particle concentration regimes.

Two synchronized high-speed video cameras captured the sand grains in motion. A 2 mm sheet of light from a 7-watt laser diode and an array of high-powered LEDs illuminated the particles. From the PTV data, we calculated the splash event impacts and ejections and trajectory characteristics of the particles in transport over flat and rippled beds. Additionally, a laser particle counter and sediment traps estimated sediment flux, while a pitot tube and sonic anemometer measured flow regimes. A TLS measured ripple dimensions.

We report the results from a set of wind tunnel experiments over flat and rippled beds that includes the direct observations of (1) the splash events across the stoss and lee slope, (2) the spatial variability of the vertical concentration profiles of particles in transport, (3) the impact, rebound, and ejection angles and velocities of splash events during low, moderate and high transport rates. We find the splash events change with transport rate. We find the splash event characteristics change with transport rate. We propose future models to include the transition of particle-to-bed interactions with sediment transport flux.
The timing of unprecedented hydrological drought under climate change
Authors: Satoh Yusuke , Yoshimura Kei , Pokhrel Yadu , Kim Hyungjun , Shiogama Hideo , Yokohata Tokuta , Hanasaki Naota , Wada Yoshihide , Burek Peter , Byers Edward , Müller Schmied Hannes , Garten Dieter , Ostberg Sebastian , Gosling Simon , Boulange Julien , Oki Taikan
Published: March 2022

Droughts that exceed the magnitudes of historical variation ranges could occur increasingly frequently under future climate conditions. However, the time of the emergence of unprecedented drought conditions under climate change has rarely been examined. Here, using multimodel hydrological simulations, we investigate the changes in the frequency of hydrological drought (defined as abnormally low river discharge) under high and low greenhouse gas concentration scenarios and existing water resource management measures and estimate the timing of the first emergence of unprecedented regional drought conditions. When investigating 59 subcontinental-scale regions, the times are detected for 11 and 18 regions under low and high greenhouse gas concentration scenarios, respectively. Three regions (Southwestern South America, Mediterranean Europe, and Northern Africa) exhibit particularly robust and early timings under the high-emission scenario. These three regions are likely to confront unprecedented conditions within the next 30 years with a high likelihood regardless of the emission scenarios. Additionally, the results obtained herein demonstrate the benefits of the lower-emission pathway in reducing the likelihood of emergence. The Paris Agreement goals are shown to be effective in reducing the likelihood to the unlikely level in most regions. However, appropriate and prior adaptation measures are considered indispensable when facing unprecedented drought conditions. The results of this study underscore the importance of improving drought preparedness within the considered time horizons.
From Predictability to Controllability: Control Simulation Experiment (CSE)
Authors: Miyoshi Takemasa , Sun Qiwen , Terasaki Koji , Maejima Yasumitsu
Published: March 2022

The Observing Systems Simulation Experiment (OSSE) is a very powerful and widely applied approach to evaluate observing systems and data assimilation methods in numerical weather prediction (NWP). In the OSSE, we generate a nature run (NR) using a model and simulate observations by sampling the NR. An independent model run with data assimilation of the simulated observations mimics an NWP system, and we compare it with the NR to evaluate the observations and data assimilation method. In this study, we extend the OSSE and design the Control Simulation Experiment (CSE), in which we add perturbations to the NR and try to modify it to a desired state. Investigating what perturbations are effective to avoid a high-impact weather event would be useful to understand the controllability of such an event. Since the weather system is chaotic, and even more so for disturbances, small differences generally lead to big differences, particularly for high-impact weather events. This suggests potentially effective control, i.e., small interventions would lead to big differences for high-impact weather events. The chaos control has been studied extensively in the field of dynamical systems theory, but taking advantage of dynamical instability to avoid certain trajectories has not been a main focus to the best of the authors’ knowledge. We first tested this idea with the Lorenz-63 3-variable model and performed an OSSE with an ensemble Kalman filter (EnKF). We extended the OSSE by adding very small perturbations (only 3% of the observation error) to the NR and found an effective approach to control the trajectory to stay in one side of the Lorenz’s butterfly attractor without shifting to the other. Following the implications and understandings from the Lorenz-63 model experiments, we tested with the Lorenz-96 40-variable model to avoid the occurrences of extreme values, mimicking to avoid extreme events in NWP. Finally, we further extended the idea to test with realistic global and regional NWP models. This presentation will summarize the concept and methodology of CSE with some proof-of-concept demonstrations with the toy models and realistic NWP models. This is an attempt to a potential paradigm change of NWP research from decades of predictability to the new era of controllability.
Fractional Vegetation Cover Dynamics of the dry valleys in Southwest China from 2000 to 2020
Authors: Guo Qiankun , Shan Zhijie , Zhong Ronghua , Duan Xingwu
Published: March 2022

The vegetation cover in China has changed significantly in the past 30 years, however evidence for vegetation cover dynamics in the dry valley region (DVR) is still lacking. This study aimed to detect fractional vegetation cover dynamics in DVR from 2000 to 2020 with MODIS products, and evaluate the effects of precipitation and hydropower construction projects on vegetation cover dynamics. The results showed that: (a) the long-term average annual fractional vegetation cover for the dry valley region, including the dry-hot valleys, dry-warm valleys and dry-temperature valleys were 0.452, 0.426, 0.504 and 0.446, respectively. Significant decreasing trend of annual FVC from 2000 to 2020 was reported for overall dry valley region. Specifically, significant reducing trends were mainly observed in the dry-hot valleys and dry-warm valleys that located in the west-south part of DVR, while significant growing trends in the dry-temperature valleys of the Min and Baishui Rivers; (b) Annual Precipitation and hydropower projects construction are two key factors that contributing to changes in annual FVC for valleys. The present study is probably the first report on vegetation cover dynamics and the effects of influencing factors in DVR of Southwest China, and helpfully for further scientific studies and restoration management practices in DVR, although more detailed studies for the changes of vegetation cover and its mechanism need to be done.
Assessing patterns of future hydrological change for Australia: insights from the National Hydrological projections 
Authors: Bende-Michl Ulrike , Wilson Louise , Sharples Wendy , Oke Alison , Hope Pandora , Matic Vjekoslav , Turner Margot , Khan Zaved , Kociuba Greg , Carrara Elisabetta
Published: March 2022

As one of the world’s driest continents, Australia’s water resources need to be carefully managed to ensure sustainable access to water for livelihoods, human well-being, and ecosystem health. Australia is also a land of extremes from floods to droughts and catastrophic wildfires which are all becoming more frequent and destructive. It is essential to understand future changes in water availability and hydrologic extremes to support the development of mitigation strategies and the planning for water infrastructure and policies. To build this understanding, the Bureau of Meteorology has released the Australian Water Outlook (AWO), a seamless national landscape water service. The AWO includes National Hydrological Projections, as well as seasonal forecast and historical products, all using the Bureau’s Australian Water Landscape Water Balance model (awo.bom.gov.au).

Projection results feature many sources of uncertainty, including how future greenhouse gas emissions will develop, how a changing climate will lead to changes to hydrological features and feedback loops, and the climate and hydrological models used to simulate those changes. Acknowledging these uncertainties, the Bureau's National Hydrological Projections ensemble provides a unique opportunity to examine impacts of future changes on Australia’s hydroclimate and its water resources. It allows nationally consistent impact assessments across multiple spatial and temporal scales. To produce these projections, three bias-correction approaches were used as well as a regional downscaling model. These methods were in turn applied to four global climate models in an operational framework resulting in a nationally consistent future change dataset for climate (rainfall, solar radiation, temperature, and wind) and hydrological (soil moisture, evapotranspiration, and runoff) variables. 

An overview of the National Hydrological Projections methods and results, including a series of 8 regional water resource assessment reports, will be presented. The reports were created to facilitate understanding and use of the data and describe future changes in regional hydrology using a novel storyline approach. The storyline approach is used to improve the communication of plausible impacts to Australia's future water availability. Plausible futures portend a drier climate for large parts of Australia which could pose challenges for future water resource management.
Multi-Spacecraft Observations of Gradual Solar Energetic Particle Events with Enhanced 3He Abundance
Authors: Bucik Radoslav , Mason Glenn M. , Gómez-Herrero Raúl , Dayeh Maher A. , Desai Mihir I. , Hart Samuel T. , Ho George C. , Lario David , Krupar Vratislav , Wimmer-Schweingruber Robert F. , Rodríguez-Pacheco Javier , Asfaw Tilaye T.
Published: March 2022

Suprathermal ions from coronal jets, characterized by enhanced 3He and heavy-ion abundances, are an essential component of the seed population accelerated by coronal mass ejection (CME)-driven shocks in gradual solar energetic particle (GSEP) events. However, the mechanisms through which CME-driven shocks gain access to these suprathermal ions and produce spectral and abundance variations in GSEP events remain largely unexplored. We study GSEP events simultaneously measured on at least two spacecraft, such as ACE, STEREO, and Solar Orbiter, where 3He finite mass peak is measured at least on one spacecraft. This presentation discusses the origin of vastly different abundances and spectral shapes in terms of variable remnant population from preceding impulsive SEP events. Furthermore, with the help of imaging observations from SDO and STEREO, we examine a possible direct contribution from parent active regions of GSEP events.
Progress of developing flood forecasting system by Today’s Earth (TE)
Authors: Ma Wenchao , Ishitsuka Yuta , Takeshima Akira , Hibino Kenshi , Yamazaki Dai , Oki Taikan , Chen Ying-Wen , Satoh Masaki , Shunji Kotsuki , Miyoshi Takemasa , Yamamoto Kosuke , Kachi Misako , Kubota Takuji , Oki Riko , Yoshimura Kei
Published: March 2022

A flood forecasting system (FFS) is widely recognized as essential to protect people’s lives and prosperities. Developing an FFS with high accuracy, longer lead time, and high resolution is the ideal goal, but there are lots of obstacles to achieving this challenge. Here, we would like to introduce our progress in the development of 5-km resolution FFS system in Japan by Today’s Earth (TE) system (Ma et al., 2021). TE was developed by the collaboration between JAXA and The University of Tokyo and is routinely run at https://www.eorc.jaxa.jp/water/index.html. Among various events, we focus on a case study for forecasting Typhoon Hagibis by assessing its forecasting performance. The results showed that this method was accurate in predicting floods at 130 locations, approximately 91.6% of the total of 142 flooded locations, with a lead time of approximately 32.75 h. In terms of precision, these successfully predicted locations accounted for 24.0% of the total of 542 locations under a flood warning. On average, the predicted flood time was approximately 8.53 h earlier than a given dike-break time. Further, we would like to present our current work for developing an FFS with much higher resolution (1 km), with a probabilistic approach by the ensemble method using NEXRA (NICAM-LETKF JAXA Research Analysis, Kotsuki et al. 2017, https://www.eorc.jaxa.jp/theme/NEXRA/) data, and other developing versions of Today’s Earth system of Global scale (https://www.eorc.jaxa.jp/water/).

 

Ma, W., Ishitsuka, Y., Takeshima, A. et al. (2021). Applicability of a nationwide flood forecasting system for Typhoon Hagibis 2019. Sci Rep 11, 10213. https://doi.org/10.1038/s41598-021-89522-8.

Kotsuki S, Miyoshi T, Terasaki K. Lien GY, Kalnay E (2017) Assimilating the global satellite mapping of precipitation data with the Nonhydrostatic Icosahedral Atmospheric Model (NICAM), J. Geophys. Res. Atmos., 122, 631–650. doi: 10.1002/2016JD025355.
Late Quaternary Stratigraphic Features in the Ilan Basin, an Active Tectonic Subsidence Basin in Taiwan
Authors: Su Pin-Ju , Chen Kuan-Yu , Lin Yi-Jung
Published: March 2022

The Ilan Basin, located at the southwestern end of the Okinawa Trough, was mostly believed to be formed due to the expansion of the Okinawa Trough. However, recent marine surveys show that they may not be directly related. On the other hand, existing terrestrial surveys concentrated on the Oligocene to Miocene formations instead of the tectonic activities during the Last Glacial period to Holocene, and contradictions remain in the interpretation of the paleo-environment. This study analyzed 40 cores of Ilan Plain, reconstructed the paleo-sedimentary environment, and interpreted the seismic profiles. We found that the transgression of the Ilan Plain in the Last Glacial period was controlled by tectonic activities. The subsequent main transgression that happened in 17.5 ka and 15~14ka was driven by the rapid sea-level rise after the Last Glacial Maximum and the Melting-water Pulse 1A event. The tectonic subsidence of the Ilan Basin was centered on the deepest part of the basement. The combination of subsidence rate and sediment supply was generally stable before 4,000 years ago, but the subsidence rate has increased significantly since then, and the sediments supply has also been increased. The sediments not only filled the deepest area in the north of Lanyang River but also left the seismic facies of forwarding propagation on the Ilan shelf. In addition, there may be another sinking center in the south before 10 thousand years ago. This study continues to establish the complete sedimentary model of the Ilan Basin and to discuss the timing and causes of the main changes in the sedimentary environment. This study will improve our understanding of the tectonic subsidence model of the Ilan Basin and the sedimentary system in the basins with significant tectonic subsidence.
Exploring the Cascadia slab structure coupling 3D thermomechinal and CPO modeling.
Authors: Fraters Menno , Billen Magali , Naliboff John , Staisch Lydia , Watt Janet
Published: March 2022

The Cascadia Subduction Zone is characterized by young subducting lithosphere, its isolation from other subducting slabs, and its ability to produce megathrust earthquakes (M>9.0) and devastating tsunamis. Due to its high potential hazard and risk, it is also a well-studied subduction zone where modern, diverse and detailed observational datasets are available through the USGS and initiatives like GeoPrisms and EarthScope. These datasets include high quality GPS, onshore and offshore geophysical imaging, magmatic and seismic anisotropy data. These datasets present an opportunity to gain insight into slab structure, tectonic evolution, and present-day seismic hazards. Still, many questions remain about the physical processes that can self-consistently explain all the observations, and better estimate seismic hazards. For example, for the slab, geologic and geophysical data suggest that there may be one or two prominent slab gaps or tears, while tomographic data does not fully constrain the depth extent of the slab. Furthermore, the overriding plate is composed of several different terranes and contain numerous active and slowly moving faults, complicating efforts to accurately constrain variations in the overriding plate present-day stress and deformation rates.

In this study we test whether comparison of observations to model predictions can distinguish between different slab geometries for the Cascadia Subduction Zone. To this end, we have created regional 3D geodynamic models of Cascadia including the Cascadia slab based on the Slab 2.0 dataset. The model setup is built with the Geodynamic World Builder and, and the models are run using the mantle convection and lithospheric dynamics code ASPECT. During the evolution of these models we track the development of the CPO (Crystal Preferred Orientation), so we can compare it against seismic anisotropy data of the region. Our presentation will focus on the preliminary results of these models and demonstrate workflows for linking the model results to surface tectonics.
Using Cd, Ba and Ni isotope systematics as novel biomarkers to decipher Archean microbial metal cycling in the ~3.0 Ga Pongola Supergroup stromatolites
Authors: Hohl Simon V. , Viehmann Sebastian
Published: March 2022

Non-traditional stable isotope systematics of bioactive metals are emerging new tools for studying the biogeochemical cycling of micronutrients in sedimentary archives through deep time. In the case of Ni and Cd, their role as cofactors for biochemical reactions is directly related to enzymatic prosses essential for variable microbial communities. While methanotrophic bacteria incorporate Ni, Cd acts as a cofactor in carbonic anhydrase activity in phototrophic bacteria and matchesnutrient-like concentration patterns complementary to phosphorous in modern open ocean environments. Ba, although not acting as a cofactor in metabolic processes, is accumulated in sedimentary barite via respiration of organic matter and thus traces the extent of microbial activity and heterotrophic remineralization. All three metals follow kinetic isotopic fractionation systematics under trace element-influx limited environmental conditions, and microbial carbonates that form from a fractionated isotope pool in ambient waters have been shown to record these isotope variations through deep time.

We show a combined Ni, Cd and Ba isotope record from the ~3.0 Ga old Pongola supergroup stromatolites from the Kaapvaal Craton (S. Africa) as novel isotope-biomarkers for microbial communities. Strong positive correlated fractionation of authigenic δ138Ba with Ba/Ca and δ112Cd with Cd/P ratios above igneous reference values reveal the presence of phototrophic and heterotrophic microbial communities building up the Pongola stromatolites.

In contrast, subdued δ60Ni isotope fractionation close to igneous reference values either argues for less influence of methanotrophic communities or non-limited Ni influx into the microbial paleo-environment. The latter is likely linked to extensive weathering of a mafic and hence Ni rich upper crust in the Archean. Co-variation with C isotopes can only be observed with Cd isotopes underlining their potential as the most promising isotope biomarker for phototrophic activity in Archean microbial habitats. Our work aims to extend the use of heavy metals that work as cofactors in enzymatic processes and their isotope systematics in biogeochemical metal cycling in paleo-environmental reconstructions to understand better metallome evolution on Earth and beyond.
Long-term climate prediction for Ireland and its surrounding
Authors: Ogungbenro Stephen , O'Beirne Catherine , Düsterhus André
Published: March 2022

Ireland is bordering the North Atlantic, and its climate is dominated by its climate modes on short to longer timescales. The Atlantic low-pressure systems, Jetstream variabilities and airmasses are features of the atmospheric circulation, which also contribute to the climate this region.  So, a long-term climate prediction of Ireland is majorly controlled by the ocean, and by other atmospheric components.

The Ocean has shown good capabilities for decadal to multi-decadal climate predictions, hence, our study adapted a coupled model to investigate seasonal changes in the climate on annual to multi-annual timescales within the Max Planck Institute for Meteorology Earth System Model (MPI-ESM).  Initialized prediction is extended to multi-decadal timescale up onto twenty lead years, and we study prediction capabilities for common climate variables in and around , by identifying major drivers and documenting their prediction skills.  Our results have shown prediction skill for surface temperature over longer timescales, and we explore these capabilities for other variables of interest.  This study opens new opportunities for better long-term predictions of climate components in the region, and our results are relevant for strategic planning.
The signature of air-sea sensible heat fluxes associated with mesoscale eddies in the South China Sea
Authors: Huang Yonglin
Published: March 2022

The impact of oceanic mesoscale eddies on sensible heat fluxes and related air-sea variables in the South China Sea, an eddy-active area, is investigated by using 20 years (2000–2019) of remotely sensed sea surface temperature, mesoscale eddy trajectories atlas with satellite altimetry and a high-resolution air-sea heat flux product. Composite analyses based on 623 cyclonic eddies (CEs) and 508 anticyclonic eddies (AEs) revealed that CEs (AEs) eddies tend to decrease (increase) the surface sensible heat fluxes over the eddies with maximum mean anomalies of -5.79W/m2 (4.36 W/m2), cool (warm) the sea surface and cause surface winds to decelerate (accelerate). The composite results of fluxes and variables anomalies are stronger near the eddies centres, but the extrema of anomalies locate westward relative to the CEs (AEs) cores due to the dominant moving direction of eddies in this region. The dynamic analysis of multiple mesoscale eddies tracks demonstrates the sustained and delayed response of the marine atmospheric boundary layer to oceanic eddies. The reduction (increase) of sensible heat flux over CEs (AEs) tracks reaches the maximum after CEs (AEs) pass 2 (3) days and averagely last for more than one week. In addition, the effect of mesoscale eddies on sensible heat fluxes increases with eddy amplitude and radius and negatively correlates with their moving speed. The results also show remarkable seasonal variations of CEs (AEs) influence on fluxes and variables anomalies, stronger in winter and weaker in summer.
An unusually long eclogitic lower crustal body imaged by the Korean nuclear explosion
Authors: Zhang Xiaoqing , Thybo Hans , Artemieva Irina M. , Xu Tao , Bai Zhiming
Published: March 2022

The Sino-Korean Craton (SKC), which consists of the North China Craton (NCC) in China and North Korea, is one of the oldest cratons on earth. Since the Paleozoic, the SKC has experienced multiple subductions of the peripheral plates and the northeastern SKC is located in a junction area. Its characteristics are being investigated by geophysical and geochemical methods, which provides insights into the formation and subsequent evolution of the continental lithosphere.

We interpret the crustal structure of the northeastern SKC with the refraction/wide-angle reflection perspective using North Korean Nuclear Explosion sources recorded by 40 permanent and 7 temporary broadband stations, which were operated by the China Earthquake Administration and the Institute of Geology and Geophysics, Chinese Academy of Science, respectively.

Primary reflection phases from a discontinuity at 30km depth have an apparent velocity of about 6.2 km/s. This phase is observed to 1200km ultra-long offset, which shows that the average crustal velocity is extremely low. Another spectacular observation is of extremely strong phases which we interpret as Moho to surface multiples of all main phases in the seismic sections. Clear upper mantle refractions (Pn) are observed with an apparent velocity around 8.05 km/s as first arrivals over the offset range 300-1000 km. All observations show that the crust of northeastern SKC is very thin (about 30km), it has a low average crust velocity (6.2km/s), and the velocity contrast at the Moho discontinuity is extraordinarily strong.

We detect the “Seismic Moho” discontinuity, which is marked by a very strong and sharp increase in velocity. We interpret this “Seismic Moho” as the top of a layer consisting of the lower crust in eclogite facies. This “Seismic Moho” does not coincide with the true Crust-Mantle Boundary, which is defined by a change from felsic/intermediate/mafic crustal rocks to the dominantly ultramafic rocks of the upper mantle in petrological terms.
Strike-slip motion in the Late Mesozoic on the East Asian continental margin: Insight from 3-D numerical models with the Tan-Lu fault
Authors: Zhou Meng , Yang Ting , Deng Lijun , Guo Peng
Published: March 2022

It is widely accepted that the subduction system along an active continental margin has significant impacts on continental motions and deformation. The longest strike-slip fault in East Asian, the Tan-Lu Fault extends through the lithosphere and parallels the East Asian margin trench could be recognized as weak zone and left more significant geological information of plate tectonics than surrounding areas ( Collettini et al., 2019 ). Previous studies have gained some common sense about the motion of the East Eurasia continent margin from the Tan-Lu fault in the Late Mesozoic. The Tan-Lu fault experienced two phases sinistral strike-slip motion under compression with a striking-length about 150~200 km ( Zhu et al.,2005, 2009; Zhao et al.,2016 ), one stage is the Late Jurassic of the obtained age of 162~150 Ma and the other stage is the Early Cretaceous of the gained age of 143Ma~132Ma ( Zhu et al.,2005, 2010, 2018; Zhang and Dong, 2008 ). However, the formation mechanism of the large strike motion is still in doubt. Zhu et al., (2018) suggest that the Mesozoic tectonism of the Tan-Lu fault zone is dominated by paleo-Pacific plate subduction and thus can reflect its subduction history, while some others think the geodynamics of the Tan-Lu fault is controlled by the combined influences of the collision between the Tibetan blocks and Eurasia and the paleo-Pacific plate subduction ( Zhang et al., 2010 ).

 

To understand whether the paleo-Pacific subduction could have a dominant impact on the tectonic activities along the Tan-Lu fault and how does it influence the overriding plate, we perform 3-D numerical simulations of oceanic-continental subduction with a weakened fault zone simulating the Tan-Lu Fault. The results indicate that the motion and deformation of the East Asian continental plate can be strongly influenced by the interaction between the paleo-Pacific plate and East Asia, especially by the coupling degree between the subduction plate and the overriding plate. The coupling degree could significantly improve when there is micro-continent from subduction plate collide with overriding plate and the overriding plate would undergo compression. The collision between micro-continents with East Eurasia continent in Late Jurassic and Early Cretaceous has been observed ( Li et al.,2020; Charvet,2013 ). From the plate reconstructions ( Müller et al.,2016 ), in the Late Mesozoic had a northward component with an average velocity 40~50 mm/yr. In our numerical model, the generation of large sinistral strike-length could explained by strong coupling caused by collision of micro-continents with Eurasia plate.
Effect of data splitting and selection of machine learning algorithms for landslide susceptibility mapping
Authors: Abraham Minu Treesa , Satyam Neelima , Pradhan Biswajeet
Published: March 2022

Landslide susceptibility maps (LSMs) are inevitable parts of regional scale landslide forecasting models. The susceptibility maps can provide the spatial probability of occurrence of landslides and have crucial role in the development and planning activities of any region. With the wide availability of satellite-based data and advanced computational facilities, data driven LSMs are being developed for different regions across the world. Since a decade, machine learning (ML) algorithms have gained wide acceptance for developing LSMs and the performance of such maps depends highly on the quality of input data and the choice of ML algorithm. This study employs a k fold cross validation technique for evaluating the performance of five different ML models, viz., Naïve Bayes (NB), Logistic Regression (LR), Random Forest (RF), K Nearest Neighbors (KNN) and Support Vector Machines (SVM), to develop LSMs, by varying the train to test ratio. The ratio is varied by changing the number folds used for k fold cross validation from 2 to 10, and its effect on each algorithm is assessed using Receiver Operating Characteristic (ROC) curves and accuracy values. The method is tested for Wayanad district, Kerala, India, which is highly affected by landslides during monsoon. The results show that RF algorithm performs better among all the five algorithms considered, and the maximum accuracy values were obtained with the value of k as 8, for all cases. The variation between the minimum and maximum accuracy values were found to be 0.6 %, 0.74 %, 1.71 %, 1.92 % and 1.83 % for NB, LR, KNN, RF and SVM respectively.
Geocenter motions derived from BDS: The impact of solar radiation force model
Authors: Huang Shi , Yuan Yongqiang , Zhang Keke , Li Xingxing
Published: March 2022

The constellation of China’s BeiDou navigation satellite system (BDS) has been fully constructed since July 2020 and provides open services for worldwide users. Due to the natural sensitivity of satellite technique to geocenter motion, BDS has the capability to determine the time series of geocenter coordinates (GCCs). The purpose of this study is to assess the impact of solar radiation pressure (SRP) modeling on the BDS-derived geocenter motion. To that end, 3-year sets of daily GCCs have been determined with data of BDS. The data was recorded over the period 2019-2021 by a global network of 93 iGMAS stations. Different SRP models including the empirical CODE orbit model (ECOM/ECOM2) and the a prior box-wing model have been applied for BDS geocenter estimation, respectively. We find that under the purely empirical SRP model, the peak-to-peak amplitude of geocenter z-coordinates (GCC-Zs) can reach to 10 cm. In additional, IGSOs would bring obvious jumps to GCC-Zs during earth eclipse periods. The introduction of an a priori box-wing model can largely mitigate the spurious signals in the spectra of GCC-Zs, presenting (13.0, 4.5, 2.1, 2.4) mm for the amplitude of the 1, 3, 5, 7 cpy signals, compared to (26.2, 5.9, 1.2, 2.0) mm in the ECOM case. However, the jumps brought by IGSOs still remains, which could be caused by distortion of optical properties. Therefore, we simultaneously estimate the optical properties together with other parameters in the processing. This model, known as a prior adjustable bow-wing model (ABW), appears to improve the orbit modeling in the eclipsing season and eliminate the negative influence of IGSOs on GCC-Zs, which is reflected in the decrease of spurious signal at periods other than annual one and the amplitude of the 1, 3, 5, 7 cpy signals for GCC-Zs are (16.2, 3.8, 1.4, 0.3) mm. The ABW solution is thus closer to the geocenter motions determined with other space-geodetic techniques.
Dynamics and variability of the Late Permian climate-carbon state in an Earth System Model
Authors: Burt Daniel , Ilyina Tatiana , Kleinen Thomas
Published: March 2022

The Late Permian climate is the background state for the climate perturbations which lead to the
Permian-Triassic Boundary (~252 Ma). The Permian-Triassic Boundary mass extinction is well established as
the largest of Earth’s mass extinctions with an estimated 90% loss of species. Climate perturbations linked to
carbon emissions from Siberian Trap volcanism are attributed as the drivers of the mass extinction through
extreme temperature increases and changes in ocean circulation and biogeochemistry. Fully-coupled Earth
System Models are required to investigate the sensitivities and feedbacks of the system to these widespread
climate perturbations. The Late Permian climate is simulated with a modified version of the Max Planck
Earth System Model v1.2 similar to that used in the 6th -phase of the Coupled Model Intercomparison Project.
Geochemical and palaeobiological proxy data are used to constrain the boundary conditions of the modelled
climate state.
The simulated Late Permian climate state is characterised by a 100 year global mean 2 m surface air
temperature of 19.7°C, rising up to 37.7°C in the low-latitude continental interior. Prevailing 100 year global
mean total precipitation patterns indicate that the continental interior was largely arid from ~50°N to ~50°S and
a rainfall maximum of up to 6.5 mm day-1 is present at the equatorial boundary of the Tethys and Panthalassic
Oceans. Dynamic terrestrial vegetation in the model is dominated by woody single-stemmed evergreens and
soft-stemmed plant functional groups. The 100 year global mean surface ocean of the Late Permian illustrates
a warm-pool across the equatorial boundary between the Tethys and Panthalassic Oceans with a maximum
temperature of 31.7°C decreasing to temperatures as low as -1.9°C near the poles. Surface salinities vary
broadly across the global oceans with 100 year global mean values ranging from 21.9, in well flushed regions
of strong freshwater flux, to 49.2, in low-latitude regions of restricted exchange. Large-scale seasonal mixing
below 60°S in the Panthalassic Ocean dominates the global meridional overturning circulation. These model
data fit within the bounds represented by the available proxy data for the Late Permian. Additionally, I will
present first results of the ocean biogeochemical state in the Hamburg Ocean Carbon Cycle model with an
extended Nitrogen-cycle. I will also illustrate the results of our investigation into the influence of the Late
Permian monsoon variability on the terrestrial vegetation and ocean carbon cycles.
Abnormal Activities of Tropical Cyclones in 2019 Over theKorean Peninsula
Authors: Moon Mincheol , Ha Kyung-Ja
Published: March 2022

Approximately, 25.6 tropical cyclones (TCs) occur in the western North Pacific (WNP) each year, of which 3.4 TCs affect the Korean Peninsula (KP). In 2019, a record of seven TCs affected the KP. We investigated and elucidated the favorable conditions influencing the TCs approaching the KP using the Weather Research and Forecasting model version 4.0 (WRFv4). The cold Maritime Continent-warm WNP sea surface temperature (SST) was found to be a major factor. The effect of the SST gradient was examined for one representative case using WRFv4 with varying SST anomalies. This study suggests that the SST gradient-induced change in the circulation over the Maritime Continent is a main factor causing the TCs to approach the KP.
Influence of stratospheric gravity waves on TID activity at middle latitudes
Authors: Goncharenko Larisa , Harvey V Lynn , Cullens Chihoko , Becker Erich , Zhang Shun-Rong , Coster Anthea
Published: March 2022

This study investigates the role of hotspots in stratospheric gravity waves (GWs) in the generation of traveling ionospheric disturbances (TIDs) at middle latitudes. We utilize observations of GWs at 35 km altitude by the Atmospheric InfraRed Sounder (AIRS) on NASA’s Aqua satellite to characterize stratospheric gravity wave activity. The evolution of GWs with altitudes extending from the stratosphere to mesosphere-lower-thermosphere (MLT) region is examined using temperature observations from the Sounding of the Atmosphere using Broadband Emission Radiometry instrument. Ground-based total electron content observations from GNSS receivers are used to characterize TID activity in the ionosphere. Simulations by the High Altitude Mechanistic general Circulation Model (HIAMCM) that is nudged to the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) reanalysis in the troposphere and stratosphere are used to study multi-step vertical coupling between the stratosphere and the thermosphere.  We investigate two case studies, the Arctic winter of 2016/2017 when a sudden stratospheric warming developed in January-February 2017, and the winter of 2019/2020 that was characterized by mostly strong polar vortex conditions. The hotspot in stratospheric GWs peaks at 55-75N at the edge of polar vortex and in a limited range of longitudes.  Our results indicate that GW activity evolves with altitude and expands to 35-40N in the MLT region. Amplifications of TIDs during times of high stratospheric GW activity are seen from ~25-30N to 60N. HIAMCM simulations indicate a very good agreement with observations in the timing of GW activity and latitudinal coverage. We conclude that TIDs are generally amplified during high stratospheric GW activity and weakened during the periods of low stratospheric GW activity (during and after SSW).