bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameterization of Directional Absorption of Orographic Gravity Waves and Its Impact on the Atmospheric General Circulation Simulated by the Weather Research and Forecasting Model
Authors: Xu Xin , Xue Ming , Teixeira Miguel A. C. , Tang Jianping , Wang Yuan 
Published: August 2019

AbstractIn this work, a new parameterization scheme is developed to account for the directional absorption of orographic gravity waves (OGWs) using elliptical mountain-wave theory. The vertical momentum transport of OGWs is addressed separately for waves with different orientations through decomposition of the total wave momentum flux (WMF) into individual wave components. With the new scheme implemented in the Weather Research and Forecasting (WRF) Model, the impact of directional absorption of OGWs on the general circulation in boreal winter is studied for the first time. The results show that directional absorption can change the vertical distribution of OGW forcing, while maintaining the total column-integrated forcing. In general, directional absorption inhibits wave breaking in the lower troposphere, producing weaker orographic gravity wave drag (OGWD) there and transporting more WMF upward. This is because directional absorption can stabilize OGWs by reducing the local wave amplitude. Owing to the increased WMF from below, the OGWD in the upper troposphere at midlatitudes is enhanced. However, in the stratosphere of mid- to high latitudes, the OGWD is still weakened due to greater directional absorption occurring there. Changes in the distribution of midlatitude OGW forcing are found to weaken the tropospheric jet locally and enhance the stratospheric polar night jet remotely. The latter occurs as the adiabatic warming (associated with the OGW-induced residual circulation) is increased at midlatitudes and suppressed at high latitudes, giving rise to stronger thermal contrast. Resolved waves are likely to contribute to the enhancement of polar stratospheric winds as well, because their upward propagation into the high-latitude stratosphere is suppressed.
Trends in Persistent Seasonal-Scale Atmospheric Circulation Patterns Responsible for Seasonal Precipitation Totals and Occurrences of Precipitation Extremes over Canada
Authors: Tan Xuezhi , Gan Thian Yew , Chen Shu , Horton Daniel E. , Chen Xiaohong , Liu Bingjun , Lin Kairong 
Published: August 2019

AbstractBoth large-scale atmospheric circulation and moisture content in the atmosphere govern regional precipitation. We partition recent changes in mean, heavy, and extreme precipitation for all seasons over Canada to changes in synoptic circulation patterns (dynamic changes) and in atmospheric moisture conditions (thermodynamic changes) using 500-hPa geopotential height and precipitation data over 1979–2014. Using the self-organizing map (SOM) cluster analysis, we identify statistically significant trends in occurrences of certain synoptic circulation patterns over the Canadian landmass, which have dynamically contributed to observed changes in precipitation totals and occurrence of heavy and extreme precipitation events over Canada. Occurrences of circulation patterns such as westerlies and ridges over western North America and the North Pacific have considerably affected regional precipitation over Canada. Precipitation intensity and occurrences of precipitation extremes associated with each SOM circulation pattern also showed statistically significant trends resulting from thermodynamic changes in the atmospheric moisture supply for precipitation events. A partition analysis based on the thermodynamic–dynamic partition method indicates that most (~90%) changes in mean and extreme precipitation over Canada resulted from changes in precipitation regimes occurring under each synoptic circulation pattern (thermodynamic changes). Other regional precipitation changes resulted from changes in occurrences of synoptic circulation patterns (dynamic changes). Because of the high spatial variability of precipitation response to changes in thermodynamic and dynamic conditions, dynamic contributions could offset thermodynamic contributions to precipitation changes over some regions if thermodynamic and dynamic contributions are in opposition to each other (negative or positive), which would result in minimal changes in precipitation intensity and occurrences of heavy and extreme precipitation events.
Variations in the Frequency of Winter Extreme Cold Days in Northern China and Possible Causalities
Authors: Yuan Chaoxia , Li Wenmao 
Published: August 2019

Abstract
Weather and climate extremes often cause devastating disasters and motivate research to improve their understanding. Here, the spatiotemporal variations in the frequency of winter extreme cold days (WECDs) in northern China (NC) were investigated. The results show that the first EOF mode reflects the spatially consistent anomalies and explains 39% of the total variance. The second EOF mode represents the east–west contrasted anomalies and explains 17% of the total variance. In the winter, when the negative Arctic Oscillation (AO) co-occurs with the stronger Siberian high (SH), cold air from the polar region is more easily advected southward, causing the increased number of WECDs in all of NC. The co-occurrence of negative AO and stronger SH may be related to excessive snow in the preceding autumn over northeastern Eurasia through the local positive feedback between the snow and surface air temperatures and the tropospheric–stratospheric interaction. On the other hand, in the winter when the negative AO co-occurs with the weaker SH, eastern NC is still under the influence of cold-air intrusion from the polar region relevant to the negative AO, whereas western NC is impacted by the anomalous warm-air advection related to the weaker SH. The weakening of the SH may be caused by the El Niño teleconnection. The reproducibility of the observed variations and possible causalities of WECDs in NC by 10 coupled models participating in CMIP5 has been assessed. All the models can reproduce the observed dominant EOF modes. The relevant large-scale circulation anomalies and possible causalities can also be well simulated by the multimodel ensemble.
Recent Increased Covariability of Tropical Cyclogenesis Latitude and Longitude over the Western North Pacific during the Extended Boreal Summer
Authors: Zhao Haikun , Zhang Jie , Klotzbach Philip J. , Chen Shaohua 
Published: August 2019

Abstract
This study examines interdecadal changes in the interannual relationship between the extended boreal summer (May–November) tropical cyclogenesis (TCG) latitude and longitude over the western North Pacific Ocean (WNP) during 1979–2016. Increasing covariability of WNP TCG latitude and longitude is observed since 1998, which is found to be closely linked to shifting ENSO conditions and a tropical Pacific climate regime shift. Accompanied by an increasing occurrence in central Pacific (CP) ENSO events during recent decades, there has been a more consistent northwestward or southeastward shift of WNP TCG location since 1998. These coherent latitude and longitude shifts were generally not evident during 1979–97, a period characterized by a more conventional eastern Pacific (EP) ENSO pattern. Our statistical results show a robust relationship between TCG latitude and the Hadley circulation and between longitude and the Walker circulation during the period prior to and since the regime shift, and a possible physical explanation for the recent increased covariability of TCG latitude and longitude is given. During 1998–2016, there is a significant association of CP ENSO events with the intensity of both the Hadley and Walker circulations that likely caused the recent increase in the covariability of TCG latitude and longitude. However, the strong association of EP ENSO events with the intensity of the Hadley circulation but not with the Walker circulation during 1979–97 weakened the covariability of TCG latitude and longitude. In addition, changes in tropical Indian Ocean sea surface temperatures appear to also importantly contribute to the recent increased covariability of WNP TCG location.
Rising Temperatures Increase Importance of Oceanic Evaporation as a Source for Continental Precipitation
Authors: Findell Kirsten L. , Keys Patrick W. , van der Ent Ruud J. , Lintner Benjamin R. , Berg Alexis , Krasting John P. 
Published: August 2019

Abstract
Understanding vulnerabilities of continental precipitation to changing climatic conditions is of critical importance to society at large. Terrestrial precipitation is fed by moisture originating as evaporation from oceans and from recycling of water evaporated from continental sources. In this study, continental precipitation and evaporation recycling processes in the Earth system model GFDL-ESM2G are shown to be consistent with estimates from two different reanalysis products. The GFDL-ESM2G simulations of historical and future climate also show that values of continental moisture recycling ratios were systematically higher in the past and will be lower in the future. Global mean recycling ratios decrease 2%–3% with each degree of temperature increase, indicating the increased importance of oceanic evaporation for continental precipitation. Theoretical arguments for recycling changes stem from increasing atmospheric temperatures and evaporative demand that drive increases in evaporation over oceans that are more rapid than those over land as a result of terrestrial soil moisture limitations. Simulated recycling changes are demonstrated to be consistent with these theoretical arguments. A simple prototype describing this theory effectively captures the zonal mean behavior of GFDL-ESM2G. Implications of such behavior are particularly serious in rain-fed agricultural regions where crop yields will become increasingly soil moisture limited.
Cloud Influence on ERA5 and AMPS Surface Downwelling Longwave Radiation Biases in West Antarctica
Authors: Silber Israel , Verlinde Johannes , Wang Sheng-Hung , Bromwich David H. , Fridlind Ann M. , Cadeddu Maria , Eloranta Edwin W. , Flynn Connor J. 
Published: August 2019

AbstractThe surface downwelling longwave radiation component (LW↓) is crucial for the determination of the surface energy budget and has significant implications for the resilience of ice surfaces in the polar regions. Accurate model evaluation of this radiation component requires knowledge about the phase, vertical distribution, and associated temperature of water in the atmosphere, all of which control the LW↓ signal measured at the surface. In this study, we examine the LW↓ model errors found in the Antarctic Mesoscale Prediction System (AMPS) operational forecast model and the ERA5 model relative to observations from the ARM West Antarctic Radiation Experiment (AWARE) campaign at McMurdo Station and the West Antarctic Ice Sheet (WAIS) Divide. The errors are calculated separately for observed clear-sky conditions, ice-cloud occurrences, and liquid-bearing cloud-layer (LBCL) occurrences. The analysis results show a tendency in both models at each site to underestimate the LW↓ during clear-sky conditions, high error variability (standard deviations &gt; 20 W m−2) during any type of cloud occurrence, and negative LW↓ biases when LBCLs are observed (bias magnitudes &gt;15 W m−2 in tenuous LBCL cases and &gt;43 W m−2 in optically thick/opaque LBCLs instances). We suggest that a generally dry and liquid-deficient atmosphere responsible for the identified LW↓ biases in both models is the result of excessive ice formation and growth, which could stem from the model initial and lateral boundary conditions, microphysics scheme, aerosol representation, and/or limited vertical resolution.
Tracer Transport within Abyssal Mixing Layers
Authors: Holmes R. M. , de Lavergne Casimir , McDougall Trevor J. 
Published: August 2019

AbstractMixing layers near sloped topography in the abyss are thought to play a critical role in the global overturning circulation. Yet the behavior of passive tracers within sloping boundary layer systems has received little attention, despite the extensive use of tracer observations to understand abyssal circulation. Here, we investigate the behavior of a passive tracer released near a sloping boundary within a flow governed by one-dimensional boundary layer theory. The spreading rate of the tracer across isopycnals is influenced by factors such as the bottom-intensification of mixing, the dipole of upwelling (in the boundary layer) and downwelling (in the outer mixing layer), and along-isopycnal diffusion. For isolated near-boundary tracer releases, the bulk diffusivity, proportional to the rate of increase of the variance of the tracer distribution in buoyancy space, is much less than what would be expected from averaging the diapycnal diffusivity over the tracer patch. This stems from the presence of the bottom boundary that prevents tracer diffusion through it. Furthermore, when along-isopycnal diffusion is weak, the boundary tends to drive the tracer up the slope toward less dense fluid on average due to asymmetries between boundary layer and interior flows. With strong along-isopycnal diffusion this upslope movement is reduced, while at the same time the average diapycnal spreading rate is increased due to a reduced influence of the bottom boundary. These results have implications for what can be learned about the characteristics of mixing near sloping boundaries from past and future tracer-release experiments.
A Method for Identifying Kolmogorov’s Inertial Subrange in the Velocity Variance Spectrum
Authors: Ortiz-Suslow David G. , Wang Qing , Kalogiros John , Yamaguchi Ryan 
Published: August 2019

AbstractKolmogorov’s inertial subrange is one of the most recognized concepts in fluid turbulence. However, the practical application of this theory to turbulent flows requires identifying subrange bandwidth. In the atmospheric boundary layer, decades of investigation support Kolmogorov’s theory, but the techniques used to identify the subrange vary and no systematic approach has emerged. The algorithm for robust identification of the inertial subrange (ARIIS) has been developed to facilitate empirical studies of the turbulence cascade. ARIIS systematically and robustly identifies the most probable subrange bandwidth in a given velocity variance spectrum. The algorithm is a novel approach in that it directly uses the expected 3/4 ratio between streamwise and transverse velocity components to locate the onset and extent of the inertial subrange within a single energy density spectrum. Furthermore, ARIIS does not assume a −5/3 power law but instead uses a robust, iterative statistical fitting technique to derive the slope over the identified range. This algorithm was tested using a comprehensive micrometeorological dataset obtained from the Floating Instrument Platform (FLIP). The analysis revealed substantial variation in the inertial subrange bandwidth and spectral slope, which may be driven, in part, by mechanical wind–wave interactions. Although demonstrated using marine atmospheric data, ARIIS is a general approach that can be used to study the energy cascade in other turbulent flows.
Trust and the city: Linking urban upbringing to neural mechanisms of trust in psychosis
Authors: Lemmers-Jansen Imke LJ , Fett Anne-Kathrin J , van Os Jim , Veltman Dick J , Krabbendam Lydia 
Published: August 2019

Objective: Elevated prevalence of non-affective psychotic disorders is often found in densely populated areas. This functional magnetic resonance imaging study investigates if reduced trust, a component of impaired social functioning in patients with psychotic disorder, is associated with urban upbringing. Methods: In total, 39 patients (22 first episode and 17 clinical high risk) and 30 healthy controls, aged 16–29, performed two multi-round trust games, with a cooperative and unfair partner during functional magnetic resonance imaging scanning. Baseline trust was operationalized as the first investment made, and changes of trust as changes in investments made over the 20 trials during the games. Urban exposure during upbringing (0–15 years) was defined as higher urban (≥2500 inhabitants/km2) or lower urban (<2500 inhabitants/km2). Results: Patients displayed lower baseline trust (first investment) than controls, regardless of urbanicity exposure. During cooperative interactions, lower-urban patients showed increasing investments. In addition, during cooperative interactions, group-by-developmental urbanicity interactions were found in the right and left amygdalae, although for the latter only at trend level. Higher urbanicity was associated with decreased activation of the left amygdala in patients and controls during investments and with increased activation of the right and left amygdalae in patients only, during repayments. During unfair interactions, no associations of urbanicity with behavior or brain activation were found. Conclusion: Urban upbringing was unrelated to baseline trust. Associations with urbanicity were stronger for patients compared to controls, suggesting greater susceptibility to urbanicity effects during the developmental period. Higher-urban patients failed to compensate for the initial distrust specifically during repeated cooperative interactions. This finding highlights potential implications for social functioning. Urban upbringing was linked to differential amygdala activation, suggesting altered mechanisms of feedback learning, but this was not associated with trust game behavior.
An Experimental Validation of Masking in IEC 60601-1-8:2006-Compliant Alarm Sounds
Authors: Bolton Matthew L. , Zheng Xi , Li Meng , Edworthy Judy Reed , Boyd Andrew D. 
Published: August 2019

Objective This research investigated whether the psychoacoustics of simultaneous masking, which are integral to a model-checking-based method, previously developed for detecting perceivability problems in alarm configurations, could predict when IEC 60601-1-8-compliant medical alarm sounds are audible. Background The tonal nature of sounds prescribed by IEC 60601-1-8 makes them potentially susceptible to simultaneous masking: where concurrent sounds render one or more inaudible due to human sensory limitations. No work has experimentally assessed whether the psychoacoustics of simultaneous masking accurately predict IEC 60601-1-8 alarm perceivability. Method In two signal detection experiments, 28 nursing students judged whether alarm sounds were present in collections of concurrently sounding standard-compliant tones. The first experiment used alarm sounds with single-frequency (primary harmonic) tones. The second experiment’s sounds included the additional, standard-required frequencies (often called subharmonics). T tests compared miss, false alarm, sensitivity, and bias measures between masking and nonmasking conditions and between the two experiments. Results Miss rates were significantly higher and sensitivity was significantly lower for the masking condition than for the nonmasking one. There were no significant differences between the measures of the two experiments. Conclusion These results validate the predictions of the psychoacoustics of simultaneous masking for medical alarms and the masking detection capabilities of our method that relies on them. The results also show that masking of an alarm’s primary harmonic is sufficient to make an alarm sound indistinguishable. Application Findings have profound implications for medical alarm design, the international standard, and masking detection methods.
Distinct roles of ezrin, radixin and moesin in maintaining the plasma membrane localizations and functions of human blood–brain barrier transporters
Authors: Hoshi Yutaro , Uchida Yasuo , Kuroda Takashi , Tachikawa Masanori , Couraud Pierre-Olivier , Suzuki Takashi , Terasaki Tetsuya 
Published: August 2019

The purpose of this study was to clarify the roles of ERM proteins (ezrin/radixin/moesin) in the regulation of membrane localization and transport activity of transporters at the human blood–brain barrier (BBB). Ezrin or moesin knockdown in a human in vitro BBB model cell line (hCMEC/D3) reduced both BCRP and GLUT1 protein expression levels on the plasma membrane. Radixin knockdown reduced not only BCRP and GLUT1, but also P-gp membrane expression. These results indicate that P-gp, BCRP and GLUT1 proteins are maintained on the plasma membrane via different ERM proteins. Furthermore, moesin knockdown caused the largest decrease of P-gp and BCRP efflux activity among the ERM proteins, whereas GLUT1 influx activity was similarly reduced by knockdown of each ERM protein. To investigate how moesin knockdown reduced P-gp efflux activity without loss of P-gp from the plasma membrane, we examined the role of PKCβI. PKCβI increased P-gp phosphorylation and reduced P-gp efflux activity. Radixin and moesin proteins were detected in isolated human brain capillaries, and their protein abundances were within a 3-fold range, compared with those in hCMEC/D3 cell line. These findings may mean that ezrin, radixin and moesin maintain the functions of different transporters in different ways at the human BBB.
Portal Placement and Biomechanical Performance of Endoscopic Proximal Hamstring Repair
Authors: Ryan Michael K. , Beason David P. , Fleisig Glenn S. , Emblom Benton A. 
Published: August 2019

Background: Proximal hamstring tendon avulsions are debilitating and commonly cause pain, weakness, and functional limitations. Open surgical repair has been the standard, but improved endoscopic techniques have enabled proximal hamstring fixation with decreased risk of infection and numbness, without the morbidity of a large incision. Purpose/Hypothesis: The purpose was to (1) describe pertinent anatomy surrounding the proximal hamstring origin in relation to 4 endoscopic portal sites and (2) test for biomechanical differences between open and endoscopic repair. It was hypothesized that (1) endoscopic proximal hamstring repair is efficacious with respect to commonly used portals and (2) there is no biomechanical difference between open and endoscopic techniques. Study Design: Descriptive and controlled laboratory study. Methods: Proximal hamstring ruptures were simulated endoscopically in 10 fresh-frozen human cadaveric pelvis specimens. Endoscopic repair was then completed on 1 limb from each specimen through 4 portals. After repair, each specimen was dissected in layers and measurements from portal tracts to pertinent anatomy were obtained. Open repair was performed on all contralateral limbs, followed by cyclical biomechanical tensile testing to failure of both the open and endoscopically repaired hamstring tendons to assess failure load and local tissue strain. Results: On average, no portal tract was closer than 2.0 cm to the sciatic nerve or inferior gluteal neurovascular bundle. Anatomic landmarks were identified that could improve the reproducibility and safety of the procedure. Biomechanical testing revealed no differences between the open and endoscopic repair techniques for any measured parameter. Conclusion: This study supports the safety and efficacy of endoscopic proximal hamstring repair through anatomic and biomechanical analyses and helps establish reproducible and recognizable landmarks that define a safe working zone. Clinical Relevance: This study maps the anatomic landscape of the proximal hamstring as encountered endoscopically and demonstrates equivalent biomechanical strength of endoscopic proximal hamstring repair, supporting this technique’s safety and efficacy.