bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regionally Different Precipitation Trends Over the Tibetan Plateau in the Warming Context: A Perspective of the Tibetan Plateau Vortices
Authors: Li Lun , Zhang Renhe , Wen Min , Lv Junmei 
Published: May 2021

AbstractPrecipitation over the Tibetan Plateau (TP) significantly affects both the local ecology and the downstream water resources. In this study, it is found that there exists an increasing precipitation trend over the northern TP but not in the southern TP, which is interpreted from the perspective of the activities of Tibetan Plateau vortices (TPVs). In the context of recent warming over the TP, the increasing rate of genesis frequency of TPVs over the northern TP is remarkably larger than that over the southern TP, which is responsible for different precipitation trends in the northern and southern TP, respectively. That is, the most significant warming over the TP appears in the upper troposphere, which intensifies the 200 hPa westerly jet north of the TP, hereby produces more favorable conditions for the genesis of TPVs over the northern TP than over southern TP, and contributes to regional difference in precipitation trends.
On the Formation of Phantom Electron Phase Space Density Peaks in Single Spacecraft Radiation Belt Data
Authors: Olifer L. , Mann I. R. , Ozeke L. G. , Morley S. K. , Louis H. L. 
Published: May 2021

AbstractThis study examines the rapid losses and acceleration of trapped relativistic and ultrarelativistic electron populations in the Van Allen radiation belt during the September 7–9, 2017 geomagnetic storm. By analyzing the dynamics of the last closed drift shell (LCDS), and the electron flux and phase space density (PSD), we show that the electron dropouts are consistent with magnetopause shadowing and outward radial diffusion to the compressed LCDS. During the recovery phase, an in‐bound pass of Van Allen Probe A shows an apparent local peak in PSD, which does not exist in reality. A careful analysis of the multipoint measurements by the Van Allen Probes reveals instead how the apparent PSD peak arises from aliasing monotonic PSD profiles which are rapidly increasing due to acceleration from very fast inwards radial diffusion. In the absence of such multisatellite conjunctions during fast acceleration events, such peaks might otherwise be associated with local acceleration processes.
Dynamics of the Tongue of Ionizations During the Geomagnetic Storm on September 7, 2015
Authors: Zhang Kedeng , Wang Hui , Liu Jing , Zheng Zhichao , He Yangfan , Gao Jie , Sun Luyuan , Zhong Yunfang 
Published: May 2021

AbstractThe dynamic evolution of the double tongue of ionization (TOI) into a single TOI at 400 km altitude during the geomagnetic storm on September 7, 2015 was studied using the Defense Meteorological Satellite Program observations and Thermosphere Ionosphere Electrodynamic General Circulation model simulations. The double TOIs occurred in the presence of increased southward Bz and weak positive By, while the single TOI occurred in the presence of northward turning of Bz and duskward turning of By. In both double and single TOI events, the plasma at middle latitudes in the afternoon (prenoon) sector was greatly enhanced due to the local upward (upward) and zonal (meridional) E × B drift. The transition process is due to both the northward and duskward turning of interplanetary magnetic field (IMF). The northward turning of IMF Bz weakens the storm enhanced density (SED) and the TOI in both afternoon and morning sectors, while the increasing duskward IMF By strengthens the morning TOI.
Two‐Moment Bulk Cloud Microphysics With Prognostic Precipitation in GFDL's Atmosphere Model AM4.0: Configuration and Performance
Authors: Guo Huan , Ming Yi , Fan Songmiao , Zhou Linjiong , Harris Lucas , Zhao Ming 
Published: May 2021

AbstractA two‐moment Morrison‐Gettelman bulk cloud microphysics with prognostic precipitation (MG2), together with a mineral dust and temperature‐dependent ice nucleation scheme, have been implemented into the Geophysical Fluid Dynamics Laboratory's Atmosphere Model version 4.0 (AM4.0). We refer to this configuration as AM4‐MG2. This paper describes the configuration of AM4‐MG2, evaluates its performance, and compares it with AM4.0. It is shown that the global simulations with AM4‐MG2 compare favorably with observations and reanalyses. The model skill scores are close to AM4.0. Compared to AM4.0, improvements in AM4‐MG2 include (a) better coastal marine stratocumulus and seasonal cycles, (b) more realistic ice fraction, and (c) dominant accretion over autoconversion. Sensitivity tests indicate that nucleation and sedimentation schemes have significant impacts on cloud liquid and ice water fields, but higher horizontal resolution (about 50 km instead of 100 km) does not.
The Annual Cycle of Energy Input, Modal Excitation and Physical Plus Biogenic Turbulent Dissipation in a Temperate Lake
Authors: Simpson John H. , Woolway R. Iestyn , Scannell Brian , Austin Martin J. , Powell Ben , Maberly Stephen C. 
Published: May 2021

AbstractA year of measurements by Doppler Current Profilers, a chain of temperature sensors and a suite of meteorological instruments has been analyzed to elucidate the seasonal cycle of the dynamical response of a temperate lake (Windermere) to surface forcing. The efficiency of energy input to the lake (Eff) was determined by comparing the rate of working by the surface wind‐stress RWy with the downward flux of momentum in the atmosphere. Eff was found to increase from values of ∼0.3% in winter mixed conditions, up to ∼1.2% during summer stratification, when internal seiches were present. Water column kinetic energy was similarly enhanced during stratification. Spectral analysis of the axial velocity showed that the first vertical mode was dominant during most of the stratified period with a less prominent second mode appearing in the early part of the summer. The observed periods and vertical structure of these modes generally accorded with estimates from internal wave theory based on density profiles. During stratification, pycnocline dissipation exhibited high variability linked to the surface forcing with an average, depth‐integrated, pycnocline dissipation rate of 2.5 × 10−5 W m−2 corresponding to ∼3%–4% of RWy. Over the same period, the dissipation rate in the bottom boundary layer (BBL) exhibited a marked diurnal variation unrelated to physical forcing. Acoustic backscatter indicated the presence of vertically migrating organisms with peak aggregation in the BBL around midday coinciding with maximum dissipation. During stratification, biogenic dissipation contributed an average of ∼36% of the total BBL dissipation rate of ∼5.7 × 10−5 W m−2.
Divergent Evolution of Glaciation Across High‐Mountain Asia During the Last Four Glacial‐Interglacial Cycles
Authors: Yan Qing , Owen Lewis A. , Zhang Zhongshi , Wang Huijun , Wei Ting , Jiang Nanxuan , Zhang Ran 
Published: May 2021

AbstractGlaciers over High‐Mountain Asia (HMA) provide a critical window into past climate change and the linkage between high and low‐latitude glaciation, but how glaciers may have varied during past glacial‐interglacial cycles remains elusive. Here, we reconstruct the timing and extent of glaciations for the last 425 kyr over HMA, using a climate‐glaciation simulation constrained by observations and glacial geologic evidence. We illustrate that there were multiple alpine‐style glaciations comparable in extent to those during the last glacial maximum during the last four glacial‐interglacial cycles. The extent and timing of glaciations vary across HMA, especially between the westerly influenced northern and the monsoonal‐influenced southern HMA. The ∼23‐kyr periodicity dominates HMA glaciation due to the critical role of precession in regulating summer temperature and precipitation. Our results, in addition to helping to fill the incomplete glacial geologic record, provide a framework to test hypotheses linking orbital‐scale climate, glaciation, and landscape evolution over HMA.
Magnetosphere‐Ionosphere Coupling of Precipitated Electrons in Diffuse Aurora Driven by Time Domain Structures
Authors: Khazanov George V. , Shen Yangyang , Vasko Ivan Y. , Artemyev Anton V. , Chu Mike 
Published: May 2021

AbstractRecent theoretical studies and the spacecraft conjugate observations between the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission and the low‐altitude Enhanced Polar Outflow Probe (e‐POP) spacecraft demonstrated the connections between broadband electrostatic fluctuations, the so called time domain structures (TDSs), and electron precipitation in the region of diffuse aurora. In this letter, we used the SuperThermal Electron Transport (STET) code to implement these theoretical and experimental results and analyze magnetosphere‐ionosphere energy interplay of the precipitated electrons that are driven by TDSs. To put TDSs electron scattering processes in the context with other wave scattering activities, ECH and whistler chorus waves are taken into account. Integrated electron energy fluxes in the diffuse aurora driven by TDSs are comparable to those driven by whistler waves. We find that including Magnetosphere‐Ionosphere coupling processes increases the integrated electron energy fluxes by more than two times than only driven by TDSs.
The First Detection of an Earthquake From a Balloon Using Its Acoustic Signature
Authors: Brissaud Quentin , Krishnamoorthy Siddharth , Jackson Jennifer M. , Bowman Daniel C. , Komjathy Attila , Cutts James A. , Zhan Zhongwen , Pauken Michael T. , Izraelevitz Jacob S. , Walsh Gerald J. 
Published: May 2021

AbstractExtreme temperature and pressure conditions on the surface of Venus present formidable technological challenges against performing ground‐based seismology. Efficient coupling between the Venusian atmosphere and the solid planet theoretically allows the study of seismically generated acoustic waves using balloons in the upper atmosphere, where conditions are far more clement. However, earthquake detection from a balloon has never been demonstrated. We present the first detection of an earthquake from a balloon‐borne microbarometer near Ridgecrest, CA in July 2019 and include a detailed analysis of the dependence of seismic infrasound, as measured from a balloon on earthquake source parameters, topography, and crustal and atmospheric structure. Our comprehensive analysis of seismo‐acoustic phenomenology demonstrates that seismic activity is detectable from a high‐altitude platform on Earth, and that Rayleigh wave‐induced infrasound can be used to constrain subsurface velocities, paving the way for the detection and characterization of such signals on Venus.
Network‐Synchronization Analysis Reveals the Weakening Tropical Circulations
Authors: Geng Zijin , Zhang Yongwen , Lu Bo , Fan Jingfang , Zhao Ziming , Chen Xiaosong 
Published: May 2021

AbstractThe impact of climate change on extreme weather is one of the most concerning problems. Climate change could cause more frequent and unexpected extreme weather. Still, synchronization features of extreme weather under climate change are not fully understood. Here, we develop a climate network approach to study global synchronization patterns of extreme events based on the 500‐hPa geopotential field. We find that a positive event synchronization (PES) network is associated with the tropical circulations in the tropics; a negative event synchronization network is associated with the large‐scale atmospheric Rossby waves in mid‐latitudes. By studying temporal evolution of the PES network, we find that the synchronization strengths in the tropics are weakening under climate change in relation to the slowing down of tropical circulations. Furthermore, our results show that the strength of synchronization in Africa and the Atlantic Ocean decrease faster than other regions.
Investigating the Link Between Outer Radiation Belt Losses and Energetic Electron Escape at the Magnetopause: A Case Study Using Multi‐Mission Observations and Simulations
Authors: Cohen I. J. , Turner D. L. , Michael A. T. , Sorathia K. A. , Ukhorskiy A. Y. 
Published: May 2021

AbstractRadiation belt flux dropout events are sudden and often significant reductions in high‐energy electrons from Earth's outer radiation belts. These losses are theorized to be due to interactions with the dayside magnetopause and possibly connected to observations of escaping magnetospheric particles. This study focuses on radiation belt losses during a moderate‐strength, nonstorm dropout event on November 21, 2016. The potential loss mechanisms and the linkage to dayside escape are investigated using combined energetic electron observations throughout the dayside magnetosphere from the Magnetospheric Multiscale and Van Allen Probes spacecraft along with global magnetohydrodynamic and test particle simulations. In particular, this nonstorm‐time event simplifies the magnetospheric conditions and removes ambiguity in the interpretation of results, allowing focus on subsequent losses from enhanced outward radial transport that can occur after initial compression and relaxation of the magnetopause boundary. The evolution of measured phase space density profiles suggest a total loss of approximately 60% of the initial radiation belt content during the event. Together the in situ observations and high‐resolution simulations help to characterize the loss by bounding the following parameters: (a) the duration of the loss, (b) the relative distribution of losses and surface area of the magnetopause over which loss occurs, and (c) the escaping flux (i.e., loss) rate across the magnetopause. In particular, this study is able to estimate the surface area of loss to less than 2.9 × 106 RE2 and the duration of loss to greater than 6 h, while also demonstrating the magnetic local time‐dependence of the escaping flux and energy spectrum.
Rectified Effects of Interannual Chlorophyll Variability on the Tropical Pacific Climate Revealed by a Hybrid Coupled Physics‐Biology Model
Authors: Tian Feng , Zhang Rong‐Hua , Wang Xiujun , Zhi Hai 
Published: May 2021

AbstractEl Niño‐Southern Oscillation (ENSO) induces large interannual chlorophyll variability (ICV) in the tropical Pacific, which modulates shortwave penetration in the upper ocean. However, the extent to which ICV can have rectified effect (higher‐frequency process impacts low‐frequency climate variability (i.e., ENSO) and mean state) in the tropical Pacific remains unclear. Here, a hybrid coupled physics‐biogeochemistry model with tunable coupling ocean‐atmosphere intensity (α) is used to examine this rectified effect. The simulations consist of a control run in which the ICV effect is represented in the model and the other with the ICV effect being purposely excluded by only reserving the climatological chlorophyll field. Results show that the ICV effect depends on α; ENSO amplitude is reduced by 12%–40% with decreased annual mean sea surface temperature by 0.05–0.4°C in the eastern equatorial Pacific when taking α = 0.8–1.15. A stability analysis reveals that the ICV effect on ENSO exhibits two feedback loops. (a) Positive (negative) chlorophyll anomalies during La Niña (El Niño) act to increase (decrease) shortwave absorption within the mixed layer, which enhances thermodynamic damping (slightly weakening ENSO amplitude). (b) Chlorophyll anomalies modulate vertical redistribution of penetrative shortwave radiation between the mixed layer and subsurface layers; this differential heating affects ocean stratification and vertical mixing, which weakens the thermocline and Ekman feedback (predominantly weakening ENSO amplitude). Additionally, ICV exhibits asymmetric effects on ENSO evolution, with the El Niño amplitude being damped stronger than La Nina; this residual effect leads to a net cooling condition in the eastern tropical Pacific.
The Mixed Layer Salinity Budget in the Central Equatorial Indian Ocean
Authors: Chi Nan‐Hsun , Lien Ren‐Chieh , D'Asaro Eric A. 
Published: May 2021

AbstractThe oceanic surface mixed layer salinity (MLS) budget of the central and eastern equatorial Indian Ocean during boreal fall and winter is studied using in situ and remote sensing measurements. Budgets on roughly 100 km scale were constructed using data from two DYNAmics of the Madden–Julian Oscillation and two Research Moored Array for African‐Asian‐Australian Monsoon Analysis and Prediction moorings near 79°E during September 2011 to January 2012. The horizontal advective salinity flux plays a significant role in the seasonal variation of equatorial MLS. In boreal fall, the equatorial and 1.5°S MLS increases due to horizontal advection and turbulent mixing, despite the freshening surface flux associated with MJOs. In boreal winter, with larger sub‐monthly variation and uncertainties, the decreasing of equatorial MLS is accounted by freshening zonal advection and surface flux, abated by salty meridional advection; the 1.5°S MLS is explained by the combination of freshening meridional advection and surface flux, and salty zonal advection. Budgets between 2011 and 2015 are investigated using data products from Tropical Rainfall Measuring Mission, Aquarius, Ocean Surface Current Analyses Real‐time, Objectively Analyzed air‐sea Fluxes, and Argo mixed layers over a wider region. The eastward development of the equatorial salinity tongue in the central to eastern Indian Ocean in boreal fall and the westward retreat in boreal winter are largely determined by the equatorial zonal current. The meridional migration of ITCZ rainfall plays a secondary role. In order to improve model prediction skills of MLS changes in the equatorial Indian Ocean, both zonal and meridional salinity advective fluxes, at a spatial scale of 1° longitude and latitude and a timescale less than days, need to be properly simulated.
Secondary Formation of Aerosols Under Typical High‐Humidity Conditions in Wintertime Sichuan Basin, China: A Contrast to the North China Plain
Authors: Wang Yujue , Hu Min , Hu Wei , Zheng Jing , Niu Hongya , Fang Xin , Xu Nan , Wu Zhijun , Guo Song , Wu Yusheng , Chen Wentai , Lu Sihua , Shao Min , Xie Shaodong , Luo Bin , Zhang Yuanhang 
Published: May 2021

AbstractThe Sichuan Basin is one of the regions suffering from severe haze pollution in southwest China. However, the secondary aerosol formation in this region is poorly understood. In this study, the chemical compositions of PM2.5 and molecular compositions of water‐soluble organics in wintertime Sichuan were measured to investigate the aerosol sources and formation under typical high relative humidity (RH) conditions. Strong correlations between PM2.5, carbonaceous aerosols and K+ suggested the influence of biomass burning. The impacts of biomass burning were also supported by the dominance of primarily emitted reduced/less oxidized nitrogen‐containing organics as well as the high peak intensities of secondarily formed nitrocatechols and methyl‐nitrocatechols. High humidity (average RH = 80%) and aerosol liquid water (ALW) in Sichuan facilitated the secondary formation of sulfate, nitrate, and secondary organic aerosols (SOA). The average sulfate oxidation ratio and nitrogen oxidation ratio in Sichuan were 2.5 and 3.1 times of those in winter Beijing (average RH = 27%). This suggested higher potentials of SO2 and NOx to form sulfate and nitrate under high‐RH conditions. The abundant aqueous‐SOA formation in Sichuan was supported by the dominance of organosulfates (OSs) and nitrooxy‐OSs in mass spectra of water‐soluble organics, while the OSs in winter Beijing were quite limited. The more abundant OS formation in Sichuan was attributed to the much higher RH, ALW, aerosol acidity, and sulfate, which favored the acidic sulfate‐catalyzed aqueous‐phase reactions for OS formation. Higher concentrations of biogenic volatile organic compounds were additional reasons for the more abundant OSs in Sichuan than in Beijing.
RBM24 exacerbates bladder cancer progression by forming a Runx1t1/TCF4/miR-625-5p feedback loop
Authors: Yin Yue-Wei , Liu Kai-Long , Lu Bao-Sai , Li Wei , Niu Ya-Lin , Zhao Chen-Ming , Yang Zhan , Guo Ping-Ying , Qi Jin-Chun 
Published: May 2021

AbstractRNA–binding motif protein 24 (RBM24) acts as a multifunctional determinant of cell fate, proliferation, apoptosis, and differentiation during development by regulating premRNA splicing and mRNA stability. It is also implicated in carcinogenesis, but the functions of RBM24 in bladder cancer (BC) remain unclear. In the present study, we revealed that RBM24 was upregulated in BC tissues. Importantly, we found that a higher level of RBM24 was correlated with poor prognosis in BC patients. Overexpression of RBM24 promoted BC cell proliferation, while depletion of RBM24 inhibited BC cell proliferation in vivo and in vitro. Mechanistically, RBM24 positively regulated Runx1t1 expression in BC cells by binding to and enhancing Runx1t1 mRNA stability. Furthermore, Runx1t1 in turn promoted RBM24 expression by interacting with the transcription factor TCF4 and suppressing the transcription of miR-625-5p, which directly targets RBM24 and suppresses RBM24 expression. RBM24-regulated BC cell proliferation was moderated via the Runx1t1/TCF4/miR-625-5p feedback loop. These results indicate that the RBM24/Runx1t1/TCF4/miR-625-5p positive feedback loop participates in BC progression. Disruption of this pathway may be a potential therapeutic strategy for BC treatment.
Imbalanced post- and extrasynaptic SHANK2A functions during development affect social behavior in SHANK2-mediated neuropsychiatric disorders
Authors: Eltokhi Ahmed , Gonzalez-Lozano Miguel A. , Oettl Lars-Lennart , Rozov Andrey , Pitzer Claudia , Röth Ralph , Berkel Simone , Hüser Markus , Harten Aliona , Kelsch Wolfgang , Smit August B. , Rappold Gudrun A. , Sprengel Rolf 
Published: May 2021

AbstractMutations inSHANKgenes play an undisputed role in neuropsychiatric disorders. Until now, research has focused on the postsynaptic function of SHANKs, and prominent postsynaptic alterations in glutamatergic signal transmission have been reported inShankKO mouse models. Recent studies have also suggested a possible presynaptic function of SHANK proteins, but these remain poorly defined. In this study, we examined how SHANK2 can mediate electrophysiological, molecular, and behavioral effects by conditionally overexpressing either wild-type SHANK2A or the extrasynaptic SHANK2A(R462X) variant. SHANK2A overexpression affected pre- and postsynaptic targets and revealed a reversible, development-dependent autism spectrum disorder-like behavior. SHANK2A also mediated redistribution of Ca2+-permeable AMPA receptors between apical and basal hippocampal CA1 dendrites, leading to impaired synaptic plasticity in the basal dendrites. Moreover, SHANK2A overexpression reduced social interaction and increased the excitatory noise in the olfactory cortex during odor processing. In contrast, overexpression of the extrasynaptic SHANK2A(R462X) variant did not impair hippocampal synaptic plasticity, but still altered the expression of presynaptic/axonal signaling proteins. We also observed an attention-deficit/hyperactivity-like behavior and improved social interaction along with enhanced signal-to-noise ratio in cortical odor processing. Our results suggest that the disruption of pre- and postsynaptic SHANK2 functions caused bySHANK2mutations has a strong impact on social behavior. These findings indicate that pre- and postsynaptic SHANK2 actions cooperate for normal neuronal function, and that an imbalance between these functions may lead to different neuropsychiatric disorders.