bluuebunny/crossref_metadata_2025 huggingface dataset:
How will southern hemisphere subtropical anticyclones respond to global warming? Mechanisms and seasonality in CMIP5 and CMIP6 model projections
Authors: Fahad Abdullah al , Burls Natalie J. , Strasberg Zachary
Published: May 2020

The anticyclonic high-pressure systems over the southern-hemisphere, subtropical oceans have a significant influence on regional climate. Previous studies of how these subtropical anticyclones will change under global warming have focused on austral summer while the winter season has remained largely uninvestigated, together with the extent to which the dominant mechanisms proposed to explain the multi-model-mean changes similarly explain the inter-model spread in projections. This study addresses these gaps by focusing on the mechanisms that drive the spread in projected future changes across the Coupled Model Intercomparison Project Phase 5 and 6 archives during both the summer and winter seasons. The southern hemisphere anticyclones intensify in strength at their center and poleward flank during both seasons in the future projections analyzed. The inter-model spread in projected local diabatic heating changes accounts for a considerable amount of the inter-model spread in the response of the South Pacific anticyclone during both seasons. However, model differences in projected zonal-mean tropospheric static stability changes, which in turn influence baroclinic eddy growth, are most influential in determining the often-strong increases in sea level pressure seen along the poleward flank of all the anticyclones during both seasons. Increased zonal-mean tropospheric static stability over the subtropics is consistent with the poleward shift in Hadley cell edge and zonal-mean sea level pressure increases. The results suggest that differences in the extent of tropical-upper-tropospheric and subtropical-lower-tropospheric warming in the southern hemisphere, via their influence on tropospheric static stability, will largely determine the fate of the anticyclones over the coming century.
Vitamin D and the hepatitis B vaccine response: a prospective cohort study and a randomized, placebo-controlled oral vitamin D3 and simulated sunlight supplementation trial in healthy adults
Authors: Kashi Daniel S. , Oliver Samuel J. , Wentz Laurel M. , Roberts Ross , Carswell Alexander T. , Tang Jonathan C. Y. , Jackson Sarah , Izard Rachel M. , Allan Donald , Rhodes Lesley E. , Fraser William D. , Greeves Julie P. , Walsh Neil P.
Published: May 2020

Purpose

To determine serum 25(OH)D and 1,25(OH)2D relationship with hepatitis B vaccination (study 1). Then, to investigate the effects on hepatitis B vaccination of achieving vitamin D sufficiency (serum 25(OH)D ≥ 50 nmol/L) by a unique comparison of simulated sunlight and oral vitamin D3 supplementation in wintertime (study 2).

Methods

Study 1 involved 447 adults. In study 2, 3 days after the initial hepatitis B vaccination, 119 men received either placebo, simulated sunlight (1.3 × standard-erythema dose, 3 × /week for 4 weeks and then 1 × /week for 8 weeks) or oral vitamin D3 (1000 IU/day for 4 weeks and 400 IU/day for 8 weeks). We measured hepatitis B vaccination efficacy as percentage of responders with anti-hepatitis B surface antigen immunoglobulin G ≥ 10 mIU/mL.

Results

In study 1, vaccine response was poorer in persons with low vitamin D status (25(OH)D ≤ 40 vs 41–71 nmol/L mean difference [95% confidence interval] − 15% [− 26, − 3%]; 1,25(OH)2D ≤ 120 vs ≥ 157 pmol/L − 12% [− 24%, − 1%]). Vaccine response was also poorer in winter than summer (− 18% [− 31%, − 3%]), when serum 25(OH)D and 1,25(OH)2D were at seasonal nadirs, and 81% of persons had serum 25(OH)D < 50 nmol/L. In study 2, vitamin D supplementation strategies were similarly effective in achieving vitamin D sufficiency from the winter vitamin D nadir in almost all (~ 95%); however, the supplementation beginning 3 days after the initial vaccination did not effect the vaccine response (vitamin D vs placebo 4% [− 21%, 14%]).

Conclusion

Low vitamin D status at initial vaccination was associated with poorer hepatitis B vaccine response (study 1); however, vitamin D supplementation commencing 3 days after vaccination (study 2) did not influence the vaccination response.

Clinical trial registry number

Study 1 NCT02416895; https://clinicaltrials.gov/ct2/show/study/NCT02416895; Study 2 NCT03132103; https://clinicaltrials.gov/ct2/show/NCT03132103.
Impact of intracellular hemin on N-type inactivation of voltage-gated K+ channels
Authors: Coburger Ina , Yang Kefan , Bernert Alisa , Wiesel Eric , Sahoo Nirakar , Swain Sandip M. , Hoshi Toshinori , Schönherr Roland , Heinemann Stefan H.
Published: May 2020

N-type inactivation of voltage-gated K+channels is conferred by the N-terminal “ball” domains of select pore-forming α subunits or of auxiliary β subunits, and influences electrical cellular excitability. Here, we show that hemin impairs inactivation of K+channels formed by Kv3.4 α subunits as well as that induced by the subunits Kvβ1.1, Kvβ1.2, and Kvβ3.1 when coexpressed with α subunits of the Kv1 subfamily. In Kvβ1.1, hemin interacts with cysteine and histidine residues in the N terminus (C7 and H10) with high affinity (EC50100 nM). Similarly, rapid inactivation of Kv4.2 channels induced by the dipeptidyl peptidase-like protein DPP6a is also sensitive to hemin, and the DPP6a mutation C13S eliminates this dependence. The results suggest a common mechanism for a dynamic regulation of Kv channel inactivation by heme/hemin in N-terminal ball domains of Kv α and auxiliary β subunits. Free intracellular heme therefore has the potential to regulate cellular excitability via modulation of Kv channel inactivation.
Yes, I can - maybe … Effects of placebo-related instructions on neuroregulation in children with ADHD
Authors: Gevensleben Holger , Schmiedeke David , Heinrich Hartmut , Rothenberger Aribert
Published: May 2020

Neurofeedback training (NFT) provides strategies for children with ADHD to achieve changes on the neurophysiological and behavioral level to attenuate ADHD symptoms. We assume self-efficacy (an “active attitude”), a core variable in successful NFT. In a randomized, double-blind controlled study, we investigated the impact of a “placebo instruction” on the EEG-regulation performance during two sessions of Theta-Beta-NFT in children with ADHD (age 8–12 years). Children receiving the information “this might be a placebo-training” showed inferior neuroregulation (n = 10) compared to children receiving a standard instruction (n = 12). Results of our pilot study are discussed in view of factors necessary for a valid training (ensuring maximal self-efficacy in the participants) and the fidelity of placebo-controlled trials in NFT-research.
A randomized, controlled, two-month pilot trial of stannous fluoride dentifrice versus sodium fluoride dentifrice after oxalate treatment for dentinal hypersensitivity
Authors: Anderson Chad J. , Kugel Gerard , Zou Yuanshu , Ferrari Marco , Gerlach Robert
Published: May 2020

Objectives

To compare the effects of a stannous fluoride dentifrice and a sodium fluoride dentifrice on dentinal hypersensitivity when used with an oxalate-based regimen combining in-office and at-home treatment.

Materials and methods

In this single-center, randomized, controlled, double-blind, pilot clinical trial, 30 subjects were professionally treated at baseline with a 3% oxalate/potassium salt solution on up to two target teeth, then randomized 1:1 to either 0.454% stannous fluoride or 0.243% sodium fluoride overlabeled dentifrice. Both groups were given 6 sensitivity strips (3.14% potassium oxalate gel) and a soft, manual toothbrush. Subjects were permitted to apply strips on up to two teeth, up to three times per tooth, at home as desired throughout the study. Dentinal sensitivity (cold air blast challenge) was assessed at baseline, immediately after post-professional treatment, and at day 60 using the Schiff scale and a Visual Analog Scale (VAS).

Results

Immediately after professional oxalate treatment, the overall mean Schiff and VAS score decreased 25.6% and 22.4% from baseline, respectively (p ≤ 0.001 for both). At day 60, further reductions in both mean scores were seen in both groups. There were no significant differences between the groups at day 60. All treatments were well tolerated.

Conclusions

In subjects treated with oxalates for dentinal hypersensitivity, both stannous fluoride and sodium fluoride dentifrices are well tolerated, are feasible for routine use, and do not detract from the desensitizing effects of an in-office and at-home oxalate combination treatment regimen.

Clinical relevance

Either stannous fluoride or sodium fluoride dentifrices can be recommended to dentinal hypersensitivity patients who undergo professional oxalate treatment.
Soil organic matter relationships with the geotechnical-hydrological parameters, mineralogy and vegetation cover of hillslope deposits in Tuscany (Italy)
Authors: Masi Elena Benedetta , Bicocchi Gabriele , Catani Filippo
Published: May 2020

Soil organic matter (SOM) represents a main fraction of superficial soil characterized by a mechanical-hydrological behaviour different from that of the inorganic fractions. In this study, a method to measure the SOM content was applied to 27 selected sites in Tuscany (central Italy) characterized by the presence of soil types common in the region: cambisols and regosols. The method included the contribution from root fragments, which is a fraction often neglected or underestimated in measurements, in the overall estimate of the SOM content. The retrieved SOM contents were analysed considering the vegetation cover at the sites and the selected attributes of geological interest, such as geotechnical parameters and the mineralogical composition of the soils. The SOM normalized to the bulk samples ranges between 1.8 and 8.9% by weight, with the highest values of the SOM content being associated with vegetation cover classes of forest and woodlands without shrubs. The SOM values showed close relationships with the abundance of the finer fractions (silt and clay) of the soil samples, and considering the relations with geotechnical properties, moderate correlations were found with the plasticity index, unit weight and effective friction angle, overall demonstrating the importance of considering SOM when the geotechnical and hydrological properties of soils are evaluated.
The Sustainable Development Goals prioritize economic growth over sustainable resource use: a critical reflection on the SDGs from a socio-ecological perspective
Authors: Eisenmenger Nina , Pichler Melanie , Krenmayr Nora , Noll Dominik , Plank Barbara , Schalmann Ekaterina , Wandl Marie-Theres , Gingrich Simone
Published: May 2020

The sustainable development goals (SDGs) were adopted in 2015, succeeding the Millennium Development Goals (MDGs). While the MDGs focused on improving well-being in the developing world, the 17 SDGs address all countries and aim at reconciling economic and social with ecological goals. We adopt a social ecology perspective and critically reflect on the SDGs’ potential for monitoring, supporting, and bringing about a transformation towards sustainability. Starting from a literature review on the SDGs, we link empirical findings from social ecology with analyses of SDG targets and indicators. First, we find that the SDGs fail to monitor absolute trends in resource use and thus prioritize economic growth over ecological integrity. Second, we discuss the contradictions between economic growth and sustainable resource use in early and late stages of industrialization processes and show that they are responsible for important trade-offs among SDG targets. Third, we analyze the transformative potential of the SDGs with a focus on the actors and institutions addressed to bring about transformative change. We find that the SDGs rely mainly on those institutions responsible for unsustainable resource use, and partly propose measures that even reinforce current trends towards less sustainability. Despite ascertaining limited transformative potential to the SDGs from an analytical perspective, we conclude by stressing the strategic relevance of the SDGs for visions, research, and practices of statt towards transformative change towards sustainability.
What limits the efficacy of coercion?
Authors: Schøyen Øivind
Published: May 2020

We model a game between an authority, seeking to implement its state identity, and a parental generation, seeking to socialize a younger generation into their own identity. The authority first selects a coercion level against the non-state identity. The parental generation then chooses whether to insurrect in response to the coercion level and, if not, decides how much to invest in socializing their children into the non-state identity. In this overlapping generations model, we formalize and explore the consequences of an intrinsic negative reaction to coercion: coercion resentment. We show how coercion resentment can create an interval where coercion has negative efficacy in imposing the state identity. This causes the rational legitimacy maximizing authority to restrain its use of coercion. We then show how this inefficacy of coercion can make certain levels of coercion unimplementable without causing the non-state identity to insurrect. This causes the long-run equilibrium size of the non-state identity group to be dependent on their initial size and, thus, path dependence. We consider the validity of the model by reviewing two historical episodes: Stalin’s secularization project (1922–1953) and the Counter-Reformation in early modern France and the Holy Roman Empire (1517–1685).
The Brain Retains: Nonhuman Primate Models for Pediatric HIV-1 in the CNS
Authors: Obregon-Perko Veronica , Bricker Katherine , Chahroudi Ann
Published: May 2020

Purpose of Review

Perinatal HIV-1 infection is associated with an increased risk for neurologic impairments. With limited access to clinical specimens, animal models could advance our understanding of pediatric central nervous system (CNS) disease and viral persistence. Here, we summarize current findings on HIV-1 CNS infection from nonhuman primate (NHP) models and discuss their implications for improving pediatric clinical outcomes.

Recent Findings

SIV/SHIV can be found in the CNS of infant macaques within 48 h of challenge. Recent studies show an impermeable BBB during SIV infection, suggesting neuroinvasion in post-partum infection is likely not wholly attributed to barrier dysfunction. Histopathological findings reveal dramatic reductions in hippocampal neuronal populations and myelination in infected infant macaques, providing a link for cognitive impairments seen in pediatric cases. Evidence from humans and NHPs support the CNS as a functional latent reservoir, harbored in myeloid cells that may require unique eradication strategies.

Studies in NHP models are uncovering early events, causes, and therapeutic targets of CNS disease as well as highlighting the importance of age-specific studies that capture the distinct features of pediatric HIV-1 infection.
Hand Tuberculosis: a Common Disease at an Uncommon Site
Authors: Tendulkar Sushrut , Shivaprakash Shashikala , Gandhi Bhupendra , Jain Paresh
Published: May 2020

Tuberculosis (TB) is one of the major health problems in developing countries. India has the highest TB burden with approximately 27% of global TB [6]. (India TB Report 2018 Revised National TB Control Programme (2018)). The most common form of tuberculosis constitutes pulmonary tuberculosis. Among extra pulmonary tuberculosis, the musculoskeletal tuberculosis accounts for about 10–15% cases (Mohd Altaf Mir, Imran Ahmad, Mihd Yaseen (2016) World J Plast Surg 5(3):313–318). Hand involvement is seen in 10% of patients with musculoskeletal disease. There has been recent interest in tuberculosis of the hand because of a rising incidence owing to increasing numbers of immigration, an aging population, and immunosuppressed people including affected patients with human immunodeficiency virus [3,7] (Centre for Disease Control (1995) MMWR 14:1–16), Al-Qattan MM, Al-Namla A, Al-Thunayan A, Al-Omawi M (2011) J Hand Surg 36:1413–1422). Tuberculous tenosynovial disease (TBTS) is the most common presentation of hand tuberculosis. In the hand, the flexor tendon sheath and radio-ulnar bursae are the most common sites of tenosynovitis. Tuberculosis of hand is more commonly seen in the dominant hand of the male population (Al-Qattan MM, Al-Namla A, Al-Thunayan A, Al-Omawi M (2011) J Hand Surg 36:1413–1422). Here, we present a case of TBTS affecting extensor compartment of dominant hand in a post renal transplant immunosuppressed individual.
Goal-oriented error estimation and mesh adaptation for shallow water modelling
Authors: Wallwork Joseph G. , Barral Nicolas , Kramer Stephan C. , Ham David A. , Piggott Matthew D.
Published: May 2020

This study presents a novel goal-oriented error estimate for the nonlinear shallow water equations solved using a mixed discontinuous/continuous Galerkin approach. This error estimator takes account of the discontinuities in the discrete solution and is used to drive two metric-based mesh adaptation algorithms: one which yields isotropic meshes and another which yields anisotropic meshes. An implementation of these goal-oriented mesh adaptation algorithms is described, including a method for approximating the adjoint error term which arises in the error estimate. Results are presented for simulations of two model tidal farm configurations computed using the Thetis coastal ocean model (Kärnä et al. in Geosci Model Dev 11(11):4359–4382, 2018). Convergence analysis indicates that meshes resulting from the goal-oriented adaptation strategies permit accurate QoI estimation using fewer computational resources than uniform refinement.
Defining racial and ethnic context with geolocation data
Authors: Moore Ryan T. , Reeves Andrew
Published: May 2020

Across disciplines, scholars strive to better understand individuals’ milieus—the people, places, and institutions individuals encounter in their daily lives. In particular, political scientists argue that racial and ethnic context shapes attitudes about candidates, policies, and fellow citizens. Yet, the current standard of measuring milieus is to place survey respondents in a geographic container and then to ascribe all that container's characteristics to the individual's milieu. Using a new dataset of over 2.6 million GPS records from over 400 individuals, we compare conventional static measures of racial and ethnic context to dynamic, precise measures of milieus. We demonstrate how low-level static measures tend to overstate how extreme individuals’ racial and ethnic contexts are and offer suggestions for future researchers.
ON THE PRODUCT OF ELEMENTS WITH PRESCRIBED TRACE
Authors: SHEEKEY JOHN , VAN DE VOORDE GEERTRUI , VOLOCH JOSÉ FELIPE
Published: May 2020

This paper deals with the following problem. Given a finite extension of fields $\mathbb{L}/\mathbb{K}$ and denoting the trace map from $\mathbb{L}$ to $\mathbb{K}$ by $\text{Tr}$, for which elements $z$ in $\mathbb{L}$, and $a$, $b$ in $\mathbb{K}$, is it possible to write $z$ as a product $xy$, where $x,y\in \mathbb{L}$ with $\text{Tr}(x)=a,\text{Tr}(y)=b$? We solve most of these problems for finite fields, with a complete solution when the degree of the extension is at least 5. We also have results for arbitrary fields and extensions of degrees 2, 3 or 4. We then apply our results to the study of perfect nonlinear functions, semifields, irreducible polynomials with prescribed coefficients, and a problem from finite geometry concerning the existence of certain disjoint linear sets.
Satellite galaxies as better tracers of the Milky Way halo mass
Authors: Han Jiaxin , Wang Wenting , Li Zhaozhou
Published: May 2020

The inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, deviations from steady-state in the tracer distribution lead to an irreducible stochastic bias. This bias is small for satellite galaxies and dark matter particles, but as large as a factor of 2 for halo stars. This is consistent with the picture that satellite galaxies closely trace the underlying phase space distribution of dark matter particles, while halo stars are less phase-mixed. As a result, the use of only ~100 satellite galaxies can achieve a significantly higher accuracy than that achievable with a much larger sample of halo stars.
Dynamical modelling of brightest cluster galaxies: Constraints on the IMF
Authors: Loubser S. I.
Published: May 2020

We study the stellar and dynamical masses, as well as the stellar populations, of brightest cluster galaxies (BCGs) located in 32 massive clusters, and for a sub-sample of these use the results to place constraints on the Initial Mass Function (IMF). We measure the spatially-resolved stellar population properties of the BCGs, such as recent star formation episodes, and use it to predict their stellar mass-to-light ratios (ϒ*POP). We find that ∼60 per cent of the BCGs have constant ϒ*POP over the radial range (<15 kpc). We also use the stellar and dynamical mass profiles to derive the stellar mass-to-light ratio from dynamics (ϒ*DYN, see Loubser, these proceedings). We directly compare ϒ*POP with ϒ*DYN, and find that for most BCGs, a Salpeter IMF is needed to explain their properties, but we also find a small subset of BCGs for which a Kroupa-like IMF is needed to explain their properties.
Coevolution (or not) of supermassive black holes and host galaxies: Black hole scaling relations are not biased by selection effects
Authors: Kormendy John
Published: May 2020

The oral version of this paper summarized Kormendy & Ho 2013, ARA&A, 51, 511. However, earlier speakers at this Symposium worried that selection effects bias the derivation of black hole scaling relations. I therefore added – and this proceedings paper emphasizes – a discussion of why we can be confident that selection effects do not bias the observed correlations between BH mass M• and the luminosity, stellar mass, and velocity dispersion of host ellipticals and classical bulges. These are the only galaxy components that show tight BH-host correlations. The scatter plots of M• with host properties for pseudobulges and disks are upper envelopes of scatter that does extend to lower BH masses. BH correlations are most consistent with a picture in which BHs coevolve only with classical bulges and ellipticals. Four physical regimes of coevolution (or not) are suggested by Kormendy & Ho 2013 and are summarized here.
Streams and the Milky Way dark matter halo
Authors: Newberg Heidi Jo , Shelton Siddhartha , Mendelsohn Eric , Weiss Jake , Arsenault Matthew , Bauer Jacob S. , Desell Travis , Judd Roland , Magdon-Ismail Malik , Newberg Lee A. , Newby Matthew , Rayment Clayton , Rice Colin , Szymanski Boleslaw K. , Thompson Jeffery M. , Ulin Steve , Varela Carlos , Widrow Lawrence M. , Willett Benjamin A.
Published: May 2020

We describe an algorithm that can fit the properties of the dwarf galaxy progenitor of a tidal stream, given the properties of that stream. We show that under ideal conditions (the Milky Way potential, the orbit of the dwarf galaxy progenitor, and the functional form of the dwarf galaxy progenitor are known exactly), the density and angular width of stars along the stream can be used to constrain the mass and radial profile of both the stellar and dark matter components of the progenitor dwarf galaxy that was ripped apart to create the stream. Our provisional fit for the parameters of the dwarf galaxy progenitor of the Orphan Stream indicates that it is less massive and has fewer stars than previous works have indicated.
Dynamics of the Milky Way Bar/Bulge
Authors: Gerhard Ortwin
Published: May 2020

Stellar surveys and dynamical models have recently led to important progress on understanding the dynamical structure of the Milky Way’s bar and central box/peanut bulge. This talk briefly reviews the density structure of the bulge and bar from star count tomography, the cylindrical rotation of bulge stars, and the measurements of their stellar masses and pattern speed that have been obtained by fitting dynamical models to the combined star count and line-of-sight velocity data. Recent work deriving absolute proper motions throughout the bulge from the VIRAC survey and Gaia has led to a new 3D measurement of the barred bulge kinematics which is expected to greatly improve the dynamical models, and has already confirmed the relatively slow pattern speed (∼40 kms−1 kpc−1) obtained from the previous dynamical and gas-dynamical modelling.
Evolution of disk galaxies in MOdified Gravity (MOG)
Authors: Ghafourian Neda , Roshan Mahmood
Published: May 2020

Evolution and the formation of bars in the galactic disks is studied in the context of Modified Gravity (MOG) by using N-body simulations. It is found that changing the value of free parameters of the model can effectively alter the strength of the bar and disk’s stability.
Healthy life expectancy in China: Modelling and implications for public and private insurance
Authors: Li Han , Hanewald Katja , Wu Shang
Published: May 2020

Already home to 23% of the global elderly population, China will experience further demographic change in the coming decades. To address the consequences of population ageing, the Chinese government is implementing major social insurance reforms and promotes the development of private insurance markets. We aim to inform these initiatives by developing a new method to project healthy life expectancy (HLE) in different regions. HLE is an important population health measure which is increasingly used in the actuarial literature. Our new approach relies on publicly available data from the Global Burden of Disease Study for life expectancy and HLE for 139 countries. We use the model to estimate HLE at birth in 2015 for 31 province-level regions in China for both males and females. We discuss the implications of our results for planned increases in the retirement age in China and for long-term care insurance pricing.
Real‐Time Earthquake Location Based on the Kalman Filter Formulation
Authors: Chen Yukuan , Zhang Haijiang , Eaton David W.
Published: May 2020

Seismic location is an essential task for earthquake monitoring. The general practice is to locate earthquakes using arrival times from all recorded stations. However, this is not well suited for real‐time applications such as the earthquake early warning, where earthquake locations need to be determined and updated as more stations are triggered. Here we have developed a real‐time linear location method based on a Kalman filter formulation. It updates location and its uncertainty whenever a station is triggered. We have demonstrated its effectiveness with synthetic and real data sets in Parkfield, California in a retrospective mode. The tests show that we can obtain relatively accurate locations and reliable uncertainties for earthquakes with 4 or 5 stations triggered. In particular, without considering the station latency, accurate earthquake locations can be achieved retrospectively in about 3.3 and 2.7 s for the 2003 San Simeon Mw6.6 earthquake and 2004 Parkfield Mw6.0 earthquake, respectively.
Observed Climatological Relationships of Extreme Daily Precipitation Events With Precipitable Water and Vertical Velocity in the Contiguous United States
Authors: Kunkel Kenneth E. , Stevens Scott E. , Stevens Laura E. , Karl Thomas R.
Published: May 2020

An analysis of 3,104 stations in the United States shows virtually every station exhibits a positive correlation between precipitable water (PW) and extreme daily precipitation (EP) with over one‐third statistically significant. To first approximation, EP scales linearly with PW, but there is nonlinear scaling at the lower and upper ends of the PW distribution. On average, EP is amplified by twice the amount of PW, but there is substantial seasonal and spatial variability caused by dynamically forced vertical velocity with stations ranging from a one‐to‐one relationship to over three‐to‐one. These latter stations are generally found in elevated terrain or near coasts and in regions and seasons affected by strong synoptic‐scale weather systems. The results also point to PW, not vertical velocity, as the key limiting factor in the most intense EP events. This has important implications for projecting changes of the most intense EP events in a warmer world.
Methane Emissions: Remote Mapping and Source Quantification Using an Open‐Path Laser Dispersion Spectrometer
Authors: Hirst Bill , Randell David , Jones Matthew , Chu Johnny , Kannath Arun , Macleod Neil , Dean Marcella , Weidmann Damien
Published: May 2020

Reducing man‐made greenhouse gas emissions depends on the effective detection and location of sources. We present a new method that remotely detects, locates, and quantifies gas emission rates by sequentially steering an optical beam between multiple retro‐reflectors. The novel open‐path laser gas sensor uses Laser Dispersion Spectroscopy (LDS), with seven beams up to 98 meters long deployed across open, flat terrain. LDS offers high precision (10–20 ppb), high dynamic range and linearity, enhanced immunity to atmospheric perturbations, with fast response to probe an area in 3 s. Simultaneous wind and concentration data were collected for four calibrated methane gas release schemes with emission rates of ~1.3 kg/hr. The resulting data were processed using a Bayesian, Markov chain Monte‐Carlo inverse solver to locate the sources and quantify their mass emission rates and uncertainty bounds. All the sources were located to within a few meters and mass emission rates established within the associated confidence bounds.
Climate Model Projections of 21st Century Global Warming Constrained Using the Observed Warming Trend
Authors: Liang Yongxiao , Gillett Nathan P. , Monahan Adam H.
Published: May 2020

The Coupled Model Intercomparison Project Phase 6 (CMIP6) archive includes larger ensembles, longer historical simulations, and models with a broader range of climate sensitivity than CMIP5. These features favor the application of observationally constrained climate projections. The 1970–2014 trend in global mean temperature is well‐correlated with projected future warming across the CMIP6 multimodel ensemble. We first evaluate an approach that weights simulations based on the realism and degree of independence of their 1970–2014 trends, by treating each historical simulation in turn as pseudo‐observations, and using the other models and weighting method to predict 21st century warming in the model concerned. The method performs well based on correlation and probabilistic measures. Applying the method using the observed 1970–2014 warming trend results in only small changes in the mean and lower bound of CMIP6 projected warming but substantially reduces the upper bound of projected early‐, mid‐ and late‐21st century warming under all SSP scenarios.
Spatial Variations in Crustal and Mantle Anisotropy Across the North American‐Caribbean Boundary on Haiti
Authors: Possee Daniel , Keir Derek , Harmon Nicholas , Rychert Catherine , Eakin Caroline , Rolandone Frédérique , Leroy Sylvie , Corbeau Jordane , Stuart Graham , Boisson Dominique , Momplaisir Roberte , Prépetit Claude
Published: May 2020

Haiti, on the island of Hispaniola, is situated across the North American‐Caribbean plate boundary at the transition point between oblique subduction in the east and a transform plate boundary in the west. Here we use shear wave splitting measurements from S waves of local (0–50 km) and intermediate depth (50–150 km) earthquakes as well as SK(K)S phases from teleseismic earthquakes to ascertain good spatial and vertical resolution of the azimuthal anisotropic structure. This allows us to place new constraints on the pattern of deformation in the crust and mantle beneath this transitional region. SK(K)S results are dominated by plate boundary parallel (E‐W) fast directions with ~1.9 s delay times, indicating subslab trench parallel mantle flow is continuing westward along the plate boundary. Intermediate depth earthquakes originating within the subducting North American plate show a mean fast polarization direction of 065° and delay time of 0.46 s, subparallel to the relative plate motion between the Caribbean and North American plates (070°). We suggest a basal shear zone within the lower ductile crust and upper lithospheric mantle as being a potential major source of anisotropy above the subducting slab. Upper crustal anisotropy is isolated using shear wave splitting measurements on local seismicity, which show consistent delay times on the order of 0.2 s. The fast polarization directions indicate that the crustal anisotropy is controlled by the fault networks in close proximity to the major strike‐slip faults, which bisect the north and south of Haiti, and by the regional stress field where faulting is less pervasive.
Decadal Trends of Speciated Non‐methane Hydrocarbons in Taipei
Authors: Ou‐Yang Chang‐Feng , Hsieh Hsin‐Cheng , Cheng Fang‐Yi , Lin Neng‐Huei , Chang Shuenn‐Chin , Wang Jia‐Lin
Published: May 2020

Selected non‐methane hydrocarbons (NMHCs) obtained from long‐term operation of the Photochemical Assessment Monitoring Stations (PAMS) in Taipei allowed for the assessment of the effectiveness of emission control measures on ozone precursors from 2007 to 2016. Despite the very pronounced diurnal and seasonal cycles of all the 51 target compounds, almost all species showed various degrees of declining trends over the decade. When dividing the 51 compounds into five groups of alkanes, alkenes, ethyne, aromatics, and isoprene, the decadal trends are assessed as −0.7 ± 0.8, −0.3 ± 0.1, −0.02 ± 0.14, −1.9 ± 1.2, and − 0.09 ± 0.02 ppbC year−1, respectively. Meanwhile, as evidenced by multiple NMHC ratios as effective indicators of atmospheric photochemical conditions, a trend of gradual lessening in the degree of photochemistry over time was noticed. Air masses in Taipei are suggested to be increasingly more contributed by local emissions and less affected by mixing with transboundary or long‐range transported influences.
Effects of Subgrid Terrain Radiative Forcing on the Ability of RegCM4.1 in the Simulation of Summer Precipitation Over China
Authors: Gu Chunlei , Huang Anning , Wu Yang , Yang Ben , Mu Xiyu , Zhang Xindan , Cai Shuxin
Published: May 2020

We implemented a subgrid terrain radiative forcing (STRF) scheme into the International Centre for Theoretical Physics, Italy, Regional Climate Model Version 4.1 (RegCM4.1) and evaluated its impacts on the summer precipitation simulation over China by comparing the model results from the experiments with and without the STRF scheme. The RegCM4.1 without the STRF scheme simulates strong East Asian summer monsoon and overestimates the summer precipitation over China. Adopting the STRF scheme in the RegCM4.1 improves the representation of surface radiation process over complex terrains, by reducing the net gain of the surface radiation energy over the Tibetan Plateau (TP). As a result, the heat released from the surface to the overlying air column decreases, thus suppressing the development of local convection over the TP. In addition, the weakened TP thermal forcing due to the STRF effect reduces the land‐sea thermal contrast, resulting in a weakened East Asian summer monsoon that produces less transport of water vapor from tropical oceans and hence weakens summer precipitation over China. Our analysis indicates that such improvement in the precipitation simulation induced by the STRF effect is mainly due to the improved simulation of precipitation intensity, particularly that associated with the moderate and heavy precipitation events, and convective processes.
The Flexible Global Ocean‐Atmosphere‐Land System Model Grid‐Point Version 3 (FGOALS‐g3): Description and Evaluation
Authors: Li Lijuan , Yu Yongqiang , Tang Yanli , Lin Pengfei , Xie Jinbo , Song Mirong , Dong Li , Zhou Tianjun , Liu Li , Wang Lu , Pu Ye , Chen Xiaolong , Chen Lin , Xie Zhenghui , Liu Hongbo , Zhang Lixia , Huang Xin , Feng Tao , Zheng Weipeng , Xia Kun , Liu Hailong , Liu Jiping , Wang Yan , Wang Longhuan , Jia Binghao , Xie Feng , Wang Bin , Zhao Shuwen , Yu Zipeng , Zhao Bowen , Wei Jilin
Published: May 2020

This paper introduces the Flexible Global Ocean‐Atmosphere‐Land System Model: Grid‐Point Version 3 (FGOALS‐g3) and evaluates its basic performance based on some of its participation in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) experiments. Our results show that many significant improvements have been achieved by FGOALS‐g3 in terms of climatological mean states, variabilities, and long‐term trends. For example, FGOALS‐g3 has a small (−0.015°C/100 yr) climate drift in 700‐yr preindustrial control (piControl) runs and smaller biases in climatological mean variables, such as the land/sea surface temperatures (SSTs) and seasonal soil moisture cycle, compared with its previous version FGOALS‐g2 during the historical period. The characteristics of climate variabilities, for example, Madden‐Julian oscillation (MJO) eastward/westward propagation ratios, spatial patterns of interannual variability of tropical SST anomalies, and relationship between the East Asian Summer Monsoon and El Niño–Southern Oscillation (ENSO), are well captured by FGOALS‐g3. In particular, the cooling trend of globally averaged surface temperature during 1940–1970, which is a challenge for most CMIP3 and CMIP5 models, is well reproduced by FGOALS‐g3 in historical runs. In addition to the external forcing factors recommended by CMIP6, anthropogenic groundwater forcing from 1965 to 2014 was incorporated into the FGOALS‐g3 historical runs.
Persistent East Equatorial Pacific Carbon Storage at the Middle Pleistocene Transition
Authors: Diz Paula , Cobelo‐García Antonio , Hernández‐Almeida Iván , Corbí Hugo , Bernasconi Stefano M.
Published: May 2020

The Middle Pleistocene Transition (MPT, ~641–920 ka) represents a period of the Quaternary climate when, in the absence of substantial changes in orbital forcing, the climate progressively shifted to the 100 ka asymmetrical glacial–interglacial cyclicity characterizing the current climate. The causes of this change remain still uncertain but several lines of evidence suggested the carbon storage of the deep ocean played a relevant role. Here we evaluate the contribution of the eastern deep tropical Pacific to the global ocean carbon sequestration and storage between 760 and 1,040 ka. We present multi‐proxy records for export production and the redox environment at the seabed from Ocean Drilling Program Site 1242 located in the deep East Equatorial Pacific. Our data indicate the development of suboxic bottom waters during early marine isotopic stage (MIS) 23 and glacial MIS 22, suggesting the capture and storage of respired carbon. Redox‐sensitive elements suggest the progressive oxygenation of the deep ocean initiated at the end of the glacial MIS 22, continued across deglaciation and ended with the accomplishment of full interglacial MIS 21. We describe this pattern as a “less complete deglacial ventilation” in that it differs from the mid‐late Pleistocene Pacific deep ocean ventilation pattern which occurs during deglaciations. The ventilation of the deep Pacific Ocean extending beyond deglaciation might have contributed to a persistent deep ocean carbon sequestration, which might have resulted in lowered atmospheric CO2 values that could have influenced the internal response of the climate system contributing to the development of the 100 ka climate variability.
Carbon Export Buffering and CO2 Drawdown by Flexible Phytoplankton C:N:P Under Glacial Conditions
Authors: Matsumoto Katsumi , Rickaby Rosalind , Tanioka Tatsuro
Published: May 2020

Modern observations indicate that variations in marine phytoplankton stoichiometry correlate with the boundaries of major surface waters. For example, phytoplankton in the oligotrophic subtropical gyres typically have much higher C:N:P ratios (i.e., higher C:P and higher N:P ratios) than those in eutrophic upwelling regions and polar regions. Such a spatial pattern points to nutrient availability as a key environmental driver of stochiometric flexibility. Environmental dependence of phytoplankton C:N:P opens unexplored possibilities for modifying the strength of the biological pump under different climate conditions. Here we present a power law formulation of C:N:P flexibility that is driven by nutrients, temperature, and light. We embed the formulation in a global ocean carbon cycle model with multiple phytoplankton types and explore biogeochemical implications under glacial conditions. We find three key controls on export C:N:P ratio: phytoplankton physiology and community structure as well as the balance in regional production at the global level. Glacial inputs of iron and sea ice expansion are important modifiers of these three controls. We also find that global export C:N:P increases substantially under glacial conditions, and this strongly buffers global carbon export against decrease and draws down approximately 20 μatm of atmospheric CO2. These results point to the importance of including phytoplankton C:N:P flexibility in a mix of mechanisms that drive atmospheric CO2 over glacial‐interglacial time scale. Finally, our simulations indicate decoupling of nutrients, which may provide a resolution to the longstanding disagreement regarding nutrient utilization in the glacial Southern Ocean derived from different nutrient proxies.
Rising Trends in Heatwave Metrics Across Southern California
Authors: Hulley Glynn C. , Dousset Benedicte , Kahn Brian H.
Published: May 2020

Research on heatwaves has gained significant impetus over the past decade due to a warming planet and rapid 21st century urbanization. This study examines driving factors influencing heatwave trends and interannual variability across Southern California (SoCal) from 1950–2020. Inland urban areas of Los Angeles county are the most susceptible to heatwaves with strong increasing trends in frequency, duration, and intensity that are closely tied to nighttime warming. Coastal and rural areas are less impacted but show a significant increase in heatwave frequency over the past two decades. Heatwave nighttime temperatures combined with high humidity have been increasing at a rapid rate of ~1°C/decade since the 1980s—elevating heat stress and mortality risk to vulnerable urban communities. The increased nighttime humidity is associated with an anomalous moisture source off the coast of Baja California that has intensified over the past decade and is linked to ocean warming trends and changes in the California current system. Heatwaves are starting earlier and ending later in the year for urban regions. This augments public health risks and sets the stage for more intense fall wildfires by enhancing the drying of fuels. Droughts and heatwaves are strongly linked, particularly in inland urban and rural areas that have a high statistical probability of heatwaves increasing in frequency (42%), duration (26%), and daily mean temperature (2.2%) during severe drought conditions. Better understanding of heatwave climate drivers and underlying physical processes could help with prediction skill, in addition to providing effective data‐driven recommendations for mitigation efforts in SoCal's vulnerable urban regions.
Constraining the Age and Evolution of the Tuaheni Landslide Complex, Hikurangi Margin, New Zealand, Using Pore‐Water Geochemistry and Numerical Modeling
Authors: Luo Min , Torres Marta E. , Kasten Sabine , Mountjoy Joshu J.
Published: May 2020

The Tuaheni Landslide Complex (TLC) on the Hikurangi Margin is subject to reactivation, yet the timing of slide emplacement remains unknown. Here we modeled pore‐water data collected from the TLC during the International Ocean Discovery Program (IODP) Expedition 372 in 2017/2018 using a transient‐state reaction‐transport modeling approach. Our simulations reveal that the TLC was formed by two separate depositional events and that the most recent one occurred 12.5 ± 2.5 ka as a coherent ~40 m sediment block that carried its initial pore‐water signature. In addition, we show that the rapid burial of pore‐water SO42− in the pre‐slide sediments consumed an additional ~5.6 × 109 mole of CH4 over the entire Tuaheni South following the most recent depositional event. These findings provide significant insights into the nature and timing of the TLC and highlight the role of slope failure on subsurface methane cycling on millennial timescales.
MJO Propagation Across the Maritime Continent: Are CMIP6 Models Better Than CMIP5 Models?
Authors: Ahn Min‐Seop , Kim Daehyun , Kang Daehyun , Lee Jiwoo , Sperber Kenneth R. , Gleckler Peter J. , Jiang Xianan , Ham Yoo‐Geun , Kim Hyemi
Published: May 2020

Many climate models struggle with a poor simulation of the Madden‐Julian Oscillation (MJO), especially its propagation across the Maritime Continent (MC). This study quantitatively evaluates the robustness of MJO propagation over the MC in climate models that participated in Coupled Model Intercomparison Project Phase 5 (CMIP5) and Phase 6 (CMIP6) with a newly developed MC propagation metric. The results show that the CMIP6 models simulate MJO propagation over the MC more realistically than the CMIP5 models. Lower free‐tropospheric moisture budget analysis highlights that the greater horizontal moisture advection is responsible for the enhanced MJO propagation over the MC. The increase in horizontal moisture advection in the CMIP6 models is mainly attributed to the steeper horizontal mean state moisture gradient around the MC, which is associated with the reduction of the equatorial dry bias.
OTREC2019: Convection Over the East Pacific and Southwest Caribbean
Authors: Fuchs‐Stone Ž. , Raymond D. J. , Sentić S.
Published: May 2020

We present preliminary results from the field program Organization of Tropical East Pacific Convection (OTREC), with measurements during August and September of 2019 using the NSF/NCAR Gulfstream V over the tropical East Pacific and Southwest Caribbean. We found that active convection in this region has predominantly bottom‐heavy vertical mass fluxes, while decaying systems exhibit top‐heavy fluxes characteristic of stratiform rain regions. As in other regions that have been studied, a strong anti‐correlation exists between the low to mid‐level moist convective instability and the column relative humidity or saturation fraction. Finally, the characteristics of convection as a function of latitude differ greatly between the Southwest Caribbean and Colombian Pacific coast on one hand, and the intertropical convergence zone to the west. In particular, the strongest convection in the former is to the south, while it is to the north in the latter, in spite of similar latitudinal sea surface temperature distributions.
Detecting Slow Slip Events From Seafloor Pressure Data Using Machine Learning
Authors: He Bing , Wei Meng , Watts D. Randolph , Shen Yang
Published: May 2020

Detecting slow slip events (SSEs) at offshore subduction zones is important to understand the slip behavior on offshore subduction megathrusts, where tsunamis can be generated. The most widely used method to detect SSEs is to measure the vertical seafloor deformation caused by SSEs using seafloor pressure data. However, due to the small signal‐to‐noise ratio and instrumental drift, such detection is very difficult. In this study, we trained a machine learning model using synthetic data to detect SSEs and applied it to real pressure data in New Zealand between 2014 and 2015. Our method detected five events, two of which are confirmed by the onshore GPS records. Besides, our model performs better than the traditional matched filter method. We conclude that machine learning could be used to detect SSEs in real seafloor pressure data. The method can be applied to other regions, especially where near trench GPS is not available.