bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lack of Change in the Projected Frequency and Persistence of Atmospheric Circulation Types Over Central Europe
Authors: Huguenin Maurice F. , Fischer Erich M. , Kotlarski Sven , Scherrer Simon C. , Schwierz Cornelia , Knutti Reto 
Published: April 2020

AbstractIn recent summers, Europe experienced record‐breaking heatwaves, wildfires (in Northern Europe), and large‐scale water scarcity. Apart from anthropogenic warming, one contribution leading to such exceptionally hot weather was a weaker jet stream allowing a quasi‐stationary high‐pressure system to persist for many days. Here, we quantify changes in the frequency and persistence of the Central European large‐scale circulation types using various climate models. Independent of the circulation type, the models project warmer and drier future summer conditions in Central Europe, but no consistent shift to a more persistent summer or winter circulation. Most of the frequency and persistence changes are small and either within the internal variability or inconsistent across models. The model projections in this study do not support the claim of more persistent weather over Central Europe. Reconciling the results of different approaches and classifications is therefore critical to understand and predict changes in extreme weather over Europe.
Temporal Magnetotellurics Reveals Mechanics of the 2012 Mount Tongariro, NZ, Eruption
Authors: Hill Graham J. , Bibby Hugh M. , Peacock Jared , Wallin Erin L. , Ogawa Yasuo , Caricchi Luca , Keys Harry , Bennie Stewart L. , Avram Yann 
Published: April 2020

AbstractMonitoring dynamics of volcanic eruptions with geophysics is challenging. In August and November 2012, two small eruptions from Mount Tongariro provided a unique opportunity to image subsurface changes caused by the eruptions. A detailed magnetotelluric survey of the Tongariro volcanic complex completed prior to the eruption (2008–2010) provides the preeruption structure of the magmatic system. A subset of the initial measurement locations was reoccupied in June 2013. Significant changes were observed in phase tensor data at sites close to the eruptive center. Although subsurface electrical resistivity changed, the geometry of the preeruptive reservoir did not. These subsurface resistivity variations are interpreted as being predominantly caused by interaction of partial melt and the overlying brine layer causing volume reduction of the brine layer through phreatic eruption. The ability to detect significant changes associated with the magma reservoir suggests that magnetotellurics can be a valuable volcano monitoring tool.
Upper Mantle Deformation of the Terror Rift and Northern Transantarctic Mountains in Antarctica: Insight From P Wave Anisotropic Tomography
Authors: Zhang Heng , Zhao Dapeng , Ju Changhui , Li Yunyue Elita , Li Guohui , Ding Min , Chen Shuze , Zhao Junmeng 
Published: April 2020

AbstractA large number of teleseismic traveltime data are used to determine the first P‐wave radial anisotropy tomography beneath the Terror Rift, the northern Transantarctic Mountains (NTAM) and the Wilkes Subglacial Basin in Antarctica. Our results show that variations of radial anisotropy occur in both horizontal and vertical directions. In the NTAM, a high‐velocity zone with positive radial anisotropy is revealed at shallower depths, which reflects the lithospheric deformation pattern formed during the Ross Orogeny. In contrast, negative radial anisotropy appears at depths >200 km under the NTAM, which is caused by the characterization of olivine fabric rather than foundering lithosphere. Beneath the western Wilkes Subglacial Basin, a two‐layer lithosphere exists that contains rift‐induced cracks. To the east of the NTAM, asthenospheric upwelling occurs at shallow depths beneath the Terror Rift. Then the upwelling asthenosphere flows northward to Mount Melbourne and southward to Mount Erebus.
Ultramafic Rock Carbonation: Constraints From Listvenite Core BT1B, Oman Drilling Project
Authors: Beinlich A. , Plümper O. , Boter E. , Müller I. A. , Kourim F. , Ziegler M. , Harigane Y. , Lafay R. , Kelemen P. B. ,   the Oman Drilling Project Science Team
Published: April 2020

AbstractThe occurrence of the quartz‐carbonate alteration assemblage (listvenite) in ophiolites indicates that ultramafic rock represents an effective sink for dissolved CO2. However, the majority of earlier studies of ultramafic rock carbonation had to rely on the surface exposure of reaction textures and field relationships. Here we present the first observations on ultramafic rock alteration obtained from the 300 m deep BT1B drill hole, ICDP Oman Drilling Project, allowing for a continuous and high‐resolution investigation. Hole BT1B recovered continuous drill core intersecting surface alluvium, 200 m of altered ultramafic rock comprising mainly listvenite and minor serpentinite bands at 90 and 180 m depth, and 100 m of the underlying metamorphic sole. Textural evidence suggests that the carbonation of fully serpentinized harzburgite commenced by non‐equilibrium growth of spheroidal carbonate characterized by sectorial zoning resulting from radially oriented low‐angle boundaries. In the serpentinite, carbonate spheroids are composed of alternating magnesite cores and dolomite rims, whereas texturally similar carbonate in the listvenite is composed of Fe‐rich magnesite cores and Ca‐Fe‐rich magnesite rims. The distinct compositions and mineral inclusions indicate that the carbonation extent was controlled by fluid accessibility resulting in the simultaneous formation of limited carbonate in the serpentinite bands and complete carbonation in the listvenite parts of BT1B. The presence of euhedral magnesite overgrowing spheroidal carbonate in the listvenite suggests near‐equilibrium conditions during the final stage of carbonation. The carbonate clumped isotope thermometry constrains carbonate crystallization between 50 °C and 250 °C, implying repeated infiltration of reactive fluids during ophiolite uplift and cooling.
Improved Internal Wave Spectral Continuum in a Regional Ocean Model
Authors: Nelson A. D. , Arbic B. K. , Menemenlis D. , Peltier W. R. , Alford M. H. , Grisouard N. , Klymak J. M. 
Published: April 2020

AbstractRecent work demonstrates that high‐resolution global models forced simultaneously by atmospheric fields and the astronomical tidal potential contain a partial internal (gravity) wave (IW) spectral continuum. Regional simulations of the MITgcm forced at the horizontal boundaries by a global run that carries a partial IW continuum spectrum are performed at the same grid spacing as the global run and at finer grid spacings in an attempt to fill out more of the IW spectral continuum. Decreasing only the horizontal grid spacing from 2 to 0.25 km greatly improves the frequency spectra and slightly improves the vertical wavenumber spectra of the horizontal velocity. Decreasing only the vertical grid spacing by a factor of 3 does not yield any significant improvements. Decreasing both horizontal and vertical grid spacings yields the greatest degree of improvement, filling the frequency spectrum out to 72 cpd. Our results suggest that improved IW spectra in regional models are possible if they are run at finer grid spacings and are forced at their lateral boundaries by remotely generated IWs. Additionally, consistency relations demonstrate that improvements in the spectra are indeed due to the existence of IWs at higher frequencies and vertical wavenumbers when remote IW forcing is included and model grid spacings decrease. By being able to simulate an IW spectral continuum to 0.25 km scales, these simulations demonstrate that one may be able to track the energy pathways of IWs from generation to dissipation and improve the understanding of processes such as IW‐driven mixing.
Strength of Linkages Between Dust and Circulation Over North Africa: Results From a Coupled Modeling System With Active Dust
Authors: Jordan Asha K. , Zaitchik Benjamin F. , Gnanadesikan Anand , Kim Dongchul , Badr Hamada S. 
Published: April 2020

AbstractNorth African dust aerosol and climate are known to covary, but modeling studies are uncertain as to whether this covariation arises from a positive feedback loop. This study aims to improve our understanding of the strength of the relationship between dust and climate over the Sahel. A fully coupled meteorology‐land‐aerosol model (NU‐WRF) is applied to simulate mineral dust emission and transport over North Africa from prerainy season to postrainy season (March–October) for the years 2002–2016; results are compared to estimates from the MODerate Resolution Imaging Spectrometer (MODIS), the NASA Modern‐Era Reanalysis for Research and Applications v2 (MERRA‐2), the MERRA‐2 Global Modeling Initiative (GMI), and the Aerosol Robotic Network (AERONET). Two model configurations (Dust‐On and Dust‐Off) are used to investigate the regional dust‐atmosphere coupling during the Sahelian rainy season by assessing the influence of land surface conditions and near‐surface meteorology on dust emission, and the impacts of dust on the atmospheric circulation features linked to climate and dust variability. Results show that coupling appears to be weak on interannual timescales, as interannual variability in dust load and dust impacts on atmospheric circulations is modest. NU‐WRF captures the general spatial and temporal variability in dust, though it underestimates the burden during dusty months, as compared to observational and reanalysis products. Model emission and transport processes during the dustiest months are consistent with other data products, and differences appear to be wind driven. Though the impacts of mineral dust on climatological summertime atmospheric circulation patterns are small, these impacts are consistent with weakened monsoon flow and a southward narrowing of the rain belt.
Stronger Global Warming on Nonrainy Days in Observations From China
Authors: Du Muye , Kleidon Axel , Sun Fubao , Renner Maik , Liu Wenbin 
Published: April 2020

AbstractNonrainy days have rather different hydrologic and radiative conditions than rainy days, but few investigations considered how these different conditions contribute to the observed global warming. Here, we show that global warming is considerably stronger on nonrainy days using observations from China. We find that trends in mean temperature on nonrainy days are about 0.1 ° C/10 yr higher than on rainy days, and that about 80% of the total temperature increase is contributed by nonrainy days. The main reason is likely to be a stronger sensitivity of downwelling longwave radiation to greenhouse forcing on nonrainy days due to fewer clouds and water vapor compared with rainy days, which is not a hydrological effect but mainly a radiative effect. Our findings are consistent with the stronger mean temperature trends in drier regions and imply that the different temperature sensitivities on nonrainy and rainy days may have profound effects on natural and social systems.
Influence of Enhanced Planetary Wave Activity on the Polar Vortex Enhancement Related to Energetic Electron Precipitation
Authors: Asikainen Timo , Salminen Antti , Maliniemi Ville , Mursula Kalevi 
Published: April 2020

AbstractThe Northern polar vortex experiences considerable interannual variability, which is also reflected to tropospheric weather. Recent research has established a link between polar vortex variations and energetic electron precipitation (EEP) from the near‐Earth space into the polar atmosphere, which is mediated by EEP‐induced chemical changes causing ozone loss in the mesosphere and stratosphere. The most dramatic changes in the polar vortex are due to sudden stratospheric warmings (SSWs). Enhanced planetary wave convergence and meridional circulation may cause an SSW, a temporary breakdown of the polar vortex. Here we study the relation of SSWs to the atmospheric response to EEP in 1957–2017 using combined ERA‐40 and ERA‐Interim reanalysis data and geomagnetic activity as a proxy of EEP. We find that the EEP‐related enhancement of the polar vortex and other associated dynamical responses are seen only during winters when an SSW occurs and that the EEP‐related changes are observed systematically slightly before the SSW onset.We show that during these times, the planetary wave activity into the stratosphere is systematically increased, thus favoring enhanced wave‐mean‐flow interaction, which can dynamically amplify the initial polar vortex enhancement caused by ozone loss. These results highlight the importance of considering planetary wave activity as a necessary condition for observing the effects of EEP on the polar vortex.
Joint Inversion of Daily and Long‐Period Geomagnetic Transfer Functions Reveals Lateral Variations in Mantle Water Content
Authors: Munch F. D. , Grayver A. V. , Guzavina M. , Kuvshinov A. V. , Khan A. 
Published: April 2020

AbstractWe present a novel approach to investigate variations in upper mantle and transition zone (MTZ) water content based on the joint analysis of electromagnetic (EM) signals originating in the ionosphere and magnetosphere. We invert EM signals (period range 6 hr to 85 days) to probe the electrical conductivity structure underneath 20 geomagnetic observatories, accounting for the complex spatial structure of the ionospheric and magnetospheric sources. The joint inversion of EM data for the daily and long‐period bands leads to significantly improved resolution in the upper mantle and MTZ. The conductivity profiles reveal significant lateral variability, which we interpret in terms of mantle water content by coupling electrical conductivity with constrains on mantle thermochemical structure derived from the analysis of seismic data. Our results suggest the existence of a relatively dry MTZ beneath Europe and a water‐enriched MTZ underneath North America and northern Asia.
Advances in the Lead Time of Sahel Rainfall Prediction With the North American Multimodel Ensemble
Authors: Giannini A. , Ali A. , Kelley C. P. , Lamptey B. L. , Minoungou B. , Ndiaye O. 
Published: April 2020

AbstractWe assess the deterministic skill in seasonal climate predictions of Sahel rainfall made with the North American Multimodel Ensemble (NMME). We find that skill for a regionally averaged rainfall index is essentially the same for forecasts for the July–September target season made as early as February/March and as late as June. The two dominant influences on the climate of the Sahel, the North Atlantic and the global tropical oceans, shape this predictability. Multimodel ensemble skill hinges on the combination of skillful predictions of the El Niño–Southern Oscillation made with one model (CMC2‐CanCM4) with those of North Atlantic sea surface temperatures made with another (NASA‐GEOSS2S).
Toward a Universal Frequency of Occurrence Distribution for Tsunamis: Statistical Analysis of a 32‐Year Bottom Pressure Record at Axial Seamount
Authors: Fine Isaac V. , Thomson Richard E. , Chadwick William W. , Fox Christopher G. 
Published: April 2020

AbstractDetailed examination of a 32‐year record of high‐resolution bottom pressure measurements at Axial Seamount (and vicinity) in the northeast Pacific identified a total of 41 tsunamis between 1986 and 2018. All of the events were associated with tsunamigenic earthquakes with magnitudes of 7.0 and greater. Statistical analysis of the data reveals that the time series of maximum tsunami amplitude and root‐mean‐square (RMS) tsunami amplitude follow strict power‐law distributions, with considerably less deviation than for coastal tide gauge records. The high statistical reliability of the seamount record is attributable to the long duration of the observations and to the low signal‐to‐noise ratio of digital open‐ocean bottom pressure records. The power law for the RMS tsunami amplitude is especially stable and follows a pure Pareto distribution (with exponent, β = 1.24) even when the minimum threshold is increased to the point that only a few events remain in the time series.
The Badhwar‐O'Neill 2020 GCR Model
Authors: Slaba T. C. , Whitman K. 
Published: April 2020

AbstractThe Badhwar‐O'Neill (BON) model has been used for some time to describe the galactic cosmic ray (GCR) environment encountered in deep space by astronauts and sensitive electronics. The most recent version of the model, BON2014, was calibrated to available measurements to reduce model errors for particles and energies of significance to astronaut exposure. Although subsequent studies showed the model to be reasonably accurate for such applications, modifications to the sunspot number (SSN) classification system and a large number of new high‐precision measurements suggested the need to develop an improved and more capable model. In this work, the BON2020 model is described. The new model relies on daily integral flux from the Advanced Composition Explorer Cosmic Ray Isotope Spectrometer (ACE/CRIS) to describe solar activity. For time periods not covered by ACE/CRIS, the updated international SSN database is used. Parameters in the new model are calibrated to available data, which include the new Alpha Magnetic Spectrometer (AMS‐02) and Payload for Antimatter Matter Exploration and Light‐nuclei Astrophysics (PAMELA) high‐precision measurements. It is found that the BON2020 model is a significant improvement over BON2014. Systematic bias associated with BON2014 has been removed. The average relative error of the BON2020 model compared to all available measurements is found to be <1%, and BON2020 is found to be within ±15% of a large fraction of the available measurements (26,269 of 27,646 → 95%).
High-efficiency second-order nonlinear processes in an optical microfibre assisted by few-layer GaSe
Authors: Jiang Biqiang , Hao Zhen , Ji Yafei , Hou Yueguo , Yi Ruixuan , Mao Dong , Gan Xuetao , Zhao Jianlin 
Published: April 2020

AbstractThe centrosymmetric nature of silica fibre precludes the realisation of second-order nonlinear processes in optical fibre systems. Recently, the integration of 2D materials with optical fibres has opened up a great opportunity to develop all-fibre active devices. Here, we demonstrate high-efficiency second-order nonlinear frequency conversions in an optical microfibre assisted with few-layer gallium selenide (GaSe) nanoflakes. Attributed to the strong evanescent field of the microfibre and ultrahigh second-order nonlinearity of the GaSe nanoflakes, second harmonic generation (SHG) and sum-frequency generation (SFG) are effectively achieved with only sub-milliwatt continuous-wave (CW) lasers in the wavelength range of 1500–1620 nm, covering the C and L telecom bands. The SHG intensity from the microfibre is enhanced by more than four orders of magnitude with the assistance of the GaSe nanoflakes on fibre nonlinear processes. Moreover, in the SFG process, the intensity transfer between different frequencies can be effectively manipulated by changing the wavelengths and powers of two pump lasers. The realised strong second-order nonlinearity in the GaSe-integrated microfibre might expand the applications of all-fibre devices in all-optical signal processing and new light source generation at awkward wavelengths.
Integrated DNA methylation analysis reveals a potential role for ANKRD30B in Williams syndrome
Authors: Kimura Ryo , Lardenoije Roy , Tomiwa Kiyotaka , Funabiki Yasuko , Nakata Masatoshi , Suzuki Shiho , Awaya Tomonari , Kato Takeo , Okazaki Shin , Murai Toshiya , Heike Toshio , Rutten Bart P. F. , Hagiwara Masatoshi 
Published: April 2020

AbstractWilliams syndrome (WS) is a rare genetic disorder, caused by a microdeletion at the 7q11.23 region. WS exhibits a wide spectrum of features including hypersociability, which contrasts with social deficits typically associated with autism spectrum disorders. The phenotypic variability in WS likely involves epigenetic modifications; however, the nature of these events remains unclear. To better understand the role of epigenetics in WS phenotypes, we integrated DNA methylation and gene expression profiles in blood from patients with WS and controls. From these studies, 380 differentially methylated positions (DMPs), located throughout the genome, were identified. Systems-level analysis revealed multiple co-methylation modules linked to intermediate phenotypes of WS, with the top-scoring module related to neurogenesis and development of the central nervous system. Notably,ANKRD30B, a promising hub gene, was significantly hypermethylated in blood and downregulated in brain tissue from individuals with WS. Most CpG sites ofANKRD30Bin blood were significantly correlated with brain regions. Furthermore, analyses of gene regulatory networks (GRNs) yielded master regulator transcription factors associated with WS. Taken together, this systems-level approach highlights the role of epigenetics in WS, and provides a possible explanation for the complex phenotypes observed in patients with WS.
Blocking GSDMD processing in innate immune cells but not in hepatocytes protects hepatic ischemia–reperfusion injury
Authors: Li Jichang , Zhao Jie , Xu Min , Li Meng , Wang Bingrui , Qu Xiaoye , Yu Chang , Hang Hualian , Xia Qiang , Wu Hailong , Sun Xuehua , Gu Jinyang , Kong Xiaoni 
Published: April 2020

AbstractPyroptosis, a proinflammatory form of programmed cell death, plays important roles in the pathogenesis of many diseases. Inflammasome activation, which has been shown in hepatic ischemia–reperfusion injury (IRI), is demonstrated to be closely associated with pyroptosis, indicating that pyroptosis may occur and perform functions in hepatic IRI. However, there is no direct evidence showing the function of pyroptosis in hepatic IRI. In this study, by detecting the pyroptosis markers, we showed that pyroptosis may be induced during hepatic IRI. Furthermore, by adopting caspase-1 inhibitors, we showed that inhibition of pyroptosis could significantly ameliorate liver injury and suppress inflammatory response during hepatic IRI. Interestingly, caspase-1 inhibitors have no protective effects on in vitro hepatocytes under hypoxic reoxygenation condition. To investigate pyroptosis induced in which specific cell types may affect hepatic IRI, we generated hepatocyte-specific Gsdmd-knockout (Hep-Gsdmd−/−) and myeloid-specific Gsdmd-knockout (LysmCre+Gsdmdf/f) mice. Functional experiments showed that compared to control mice (Gsdmdf/f), there were alleviated liver injury and inflammation in LysmCre+Gsdmdf/f mice, but not in AlbCre+Gsdmdf/f mice. In parallel in vitro studies, cytokine expression and production decreased in bone-marrow-derived macrophages and Kupffer cells from LysmCre+Gsdmdf/f mice compared to their controls. Our findings demonstrated that pyroptosis in innate immune cells aggravates hepatic IRI and implied that hepatic IRI could be protected by blocking pyroptosis, which may become a potential therapeutic target in the clinic.