bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deriving Tidal Structure From Satellite Image Time Series
Authors: Geyman Emily C. , Maloof Adam C. 
Published: January 2020

AbstractIn shallow coastal regions, tides often control the water flux, which in turn directs sediment transport, nutrient delivery, and geochemical gradients. However, tides in shallow areas are spatially heterogeneous, making it challenging to constrain the geographic structure of tidal phase and amplitude without extensive networks of tide gauges. We present a simple remote sensing method for deriving tidal structure from satellite time series. Our method is based on two observations: (1) Tidally driven variations in water depth can be detected as changes in pixel intensity in optical satellite imagery, and (2) repeating passes by an orbiting satellite capture a region at different phases of the tidal cycle. By stacking multiple satellite acquisitions of a shallow bank, we can compute the relative tidal phase and amplitude for each pixel location, thereby resolving a detailed map of tidal propagation and attenuation. While our method requires a set of local water‐depth measurements to calibrate the color‐to‐depth relationship and compute tidal amplitude (in meters), our method can produce spatial estimates of tidal phase and relative amplitude without any site‐specific calibration data. As an illustration of the method, we use Landsat imagery to derive the spatial structure of tides on the Great Bahama Bank, estimating tidal phase and amplitude with mean absolute errors of 15 min and 0.15 m, respectively.
Energy Flow in the Region 2 Field‐Aligned Current Region Under Quasi‐steady Convection
Authors: Ebihara Yusuke , Lee Lou‐Chuang , Tanaka Takashi 
Published: January 2020

AbstractWe investigated energy flow in the inner magnetosphere on the basis of the results obtained by a global magnetohydrodynamic simulation. When the magnetosphere is exposed to a southward interplanetary magnetic field, the magnetosphere undergoes quasi‐steady convection. Downward (earthward) Poynting flux is found in the polar cap, which is consistent with previous observations. However, Poynting flux appears to be upward (antiearthward) in the equatorward region of the auroral oval. The Region 2 field‐aligned current (FAC) is embedded in the upward Poynting flux region. The upward Poynting flux is closely associated with space charge deposited by the ionospheric Hall current under inhomogeneous ionospheric conductivity. The space charge gives rise to shear flow of plasma, which is transmitted upward to the magnetosphere. The shear flow generates additional Region 2 FAC, at least, in the low‐altitude magnetosphere. Spatial distribution of the Region 2 FAC appears to depend on altitude, suggesting the significant influence of the ionosphere in the Region 2 FAC region. We traced integral curves of Poynting flux (S curves) backward from a magnetic field line in the Region 2 FAC region and found that the S curves originate either in the solar wind and in the earthward‐most boundary of the simulation. These simulation results suggest that the ionosphere participates in the generation of the Region 2 FAC, and the ionosphere is a mediator to feed energy to the inner magnetosphere under the quasi‐steady convection.
Arctic Ocean Surface Energy Flux and the Cold Halocline in Future Climate Projections
Authors: Metzner Enrico P. , Salzmann Marc , Gerdes Rüdiger 
Published: January 2020

AbstractOcean heat transport is often thought to play a secondary role for Arctic surface warming in part because warm water which flows northward is prevented from reaching the surface by a cold and stable halocline layer. However, recent observations in various regions indicate that occasionally, warm water is found directly below the surface mixed layer. Here we investigate Arctic Ocean surface energy fluxes and the cold halocline layer in climate model simulations from the Coupled Model Intercomparison Project Phase 5. An ensemble of 15 models shows decreased sea ice formation and increased ocean energy release during fall, winter, and spring for a high‐emission future scenario. Along the main pathways for warm water advection, this increased energy release is not locally balanced by increased Arctic Ocean energy uptake in summer. Because during Arctic winter, the ocean mixed layer is mainly heated from below, we analyze changes of the cold halocline layer in the monthly mean Coupled Model Intercomparison Project Phase 5 data. Fresh water acts to stabilize the upper ocean as expected based on previous studies. We find that in spite of this stabilizing effect, periods in which warm water is found directly or almost directly below the mixed layer and which occur mainly in winter and spring become more frequent in high‐emission future scenario simulations, especially along the main pathways for warm water advection. This could reduce sea ice formation and surface albedo.
Extratropical Prediction Skill of the Subseasonal‐to‐Seasonal (S2S) Prediction Models
Authors: Son Seok‐Woo , Kim Hera , Song Kanghyun , Kim Sang‐Wook , Martineau Patrick , Hyun Yu‐Kyung , Kim Yoonjae 
Published: January 2020

AbstractThe deterministic prediction skill of the 10 operational models participating in the subseasonal‐to‐seasonal (S2S) prediction project is assessed for both the extratropical stratosphere and troposphere. Based on the mean squared skill score of 50‐ and 500‐hPa geopotential height forecasts, the overall prediction skill is on average 16 days in the stratosphere and 9 days in the troposphere. The high‐top models with a fully resolved stratosphere typically have a higher prediction skill than the low‐top models. Among them, the European Centre for Medium‐Range Weather Forecasts model shows the best performance in both hemispheres. The decomposition of model errors reveals that eddy errors are more important than zonal‐mean errors in both the stratosphere and troposphere. While the errors in the stratosphere are dominated by planetary‐scale eddies, those in the troposphere are equally influenced by planetary‐ and synoptic‐scale eddies. This result indicates that subseasonal‐to‐seasonal prediction could be improved by better representing planetary‐scale wave activities in the model.
Constraining the Surface Flux of Sea Spray Particles From the Southern Ocean
Authors: Hartery S. , Toohey D. , Revell L. , Sellegri K. , Kuma P. , Harvey M. , McDonald A. J. 
Published: January 2020

AbstractModeling the shortwave radiation balance over the Southern Ocean region remains a challenge for Earth system models. To investigate whether this is related to the representation of aerosol‐cloud interactions, we compared measurements of the total number concentration of sea spray‐generated particles within the Southern Ocean region to model predictions thereof. Measurements were conducted from a container laboratory aboard the R/V Tangaroa throughout an austral summer voyage to the Ross Sea. We used source‐receptor modeling to calculate the sensitivity of our measurements to upwind surface fluxes. From this approach, we could constrain empirical parameterizations of sea spray surface flux based on surface wind speed and sea surface temperature. A newly tuned parameterization for the flux of sea spray particles based on the near‐surface wind speed is presented. Comparisons to existing model parameterizations revealed that present model parameterizations led to overestimations of sea spray concentrations. In contrast to previous studies, we found that including sea surface temperature as an explanatory variable did not substantially improve model‐measurement agreement. To test whether or not the parameterization may be applicable globally, we conducted a regression analysis using a database of in situ whitecap measurements. We found that the key fitting parameter within this regression agreed well with the parameterization of sea spray flux. Finally, we compared calculations from the best model of surface flux to boundary layer measurements collected onboard an aircraft throughout the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES), finding good agreement overall.
The Influence of Frost Weathering on Debris Flow Sediment Supply in an Alpine Basin
Authors: Rengers F. K. , Kean Jason W. , Reitman Nadine G. , Smith Joel B. , Coe Jeffrey A. , McGuire Luke A. 
Published: January 2020

Rocky, alpine mountains are prone to mass wasting from debris flows. The Chalk Cliffs study area (central Colorado, USA) produces debris flows annually. These debris flows are triggered when overland flow driven by intense summer convective storms mobilizes large volumes of sediment within the channel network. Understanding the debris flow hazard in this, and similar alpine settings, requires determining the magnitude of sediment accumulation between debris flow seasons and identifying the control on sediment production. To address these knowledge gaps, we measured changes in sediment production using a sediment retention fence to quantify how sedimentation was influenced by temperature at the plot scale. These measurements were extrapolated to a larger area, where we extended the sediment fence results to explore how rockfall sedimentation contributed to channel refilling between active debris flow periods. This work shows that debris flow channel refilling is correlated with low temperatures and time in the frost‐cracking window, implicating frost‐weathering mechanisms as a key driver of sedimentation. This sediment production process resulted in a large amount of sediment accumulation during a single winter season in our study reach (up to 0.4 m in some locations). Using these observations, we develop a channel refilling model that generally describes the mass balance of debris flow watersheds in alpine areas.
Attenuation‐factor error shaping technique for split CDAC in SAR ADCs
Authors: Sun Jie , Li Xin , Yan Chenggang , Liu Weiqiang 
Published: January 2020

A shaping technique is proposed to remedy the attenuation‐factor error in the split capacitor‐digital‐to‐analogue converter (CDAC) of a successive‐approximation‐register (SAR) ADC. By feeding back the previous quantised value of the least significant bit part to the most significant bit part, the inaccurate attenuation‐factor error caused by mismatches and parasitic components is shaped to high frequency. The in‐band dynamic performance is significantly improved without any calibration. Simulation results show that the proposed attenuation‐factor shaping technique improves the spurious‐free‐dynamic‐range by 10 dB, whereas the number of capacitors increases only 1.2%.
Asymmetric expansion of coronal mass ejections in the low corona
Authors: Cremades H. , Iglesias F. A. , Merenda L. A. 
Published: January 2020

Aims. Understanding how magnetic fields are structured within coronal mass ejections (CMEs), and how they evolve from the low corona into the heliosphere, is a major challenge for space weather forecasting and for solar physics. The study of CME morphology is a particularly auspicious approach to this problem, given that it holds a close relationship with the CME magnetic field configuration. Although earlier studies have suggested an asymmetry in the width of CMEs in orthogonal directions, this has not been inspected using multi-viewpoint observations.
Methods. The improved spatial, temporal, and spectral resolution, added to the multiple vantage points offered by missions of the Heliophysics System Observatory, constitute a unique opportunity to gain insight into this regard. We inspect the early evolution (below ten solar radii) of the morphology of a dozen CMEs occurring under specific conditions of observing spacecraft location and CME trajectory, favorable to reduce uncertainties typically involved in the 3D reconstruction used here. These events are carefully reconstructed by means of a forward modeling tool using simultaneous observations of the Solar-Terrestrial Relations Observatory (STEREO) Extreme Ultraviolet Imager and the Solar Dynamics Observatory Atmospheric Imaging Assembly as input when originating low in the corona, and followed up in the outer fields of view of the STEREO and the Solar and Heliospheric Observatory coronagraphs. We then examine the height evolution of the morphological parameters arising from the reconstructions.
Results. The multi-viewpoint analysis of this set of CMEs revealed that their initial expansion – below three solar radii – is considerably asymmetric and non-self-similar. Both angular widths, namely along the main axes of CMEs (AWL) and in the orthogonal direction (AWD, representative of the flux rope diameter), exhibit much steeper change rates below this height, with the growth rate of AWL found to be larger than that of AWD, also below that height. Angular widths along the main axes of CMEs are on average ≈1.8 times larger than widths in the orthogonal direction AWD. The ratios of the two expansion speeds, namely in the directions of CMEs main axes and in their orthogonal, are nearly constant in time after ∼4 solar radii, with an average ratio ≈1.6. Heights at which the width change rate is defined to stabilize are greater for AWL than for AWD.
Coordination within the remote sensing payload on the Solar Orbiter mission
Authors: Auchère F. , Andretta V. , Antonucci E. , Bach N. , Battaglia M. , Bemporad A. , Berghmans D. , Buchlin E. , Caminade S. , Carlsson M. , Carlyle J. , Cerullo J. J. , Chamberlin P. C. , Colaninno R. C. , Davila J. M. , De Groof A. , Etesi L. , Fahmy S. , Fineschi S. , Fludra A. , Gilbert H. R. , Giunta A. , Grundy T. , Haberreiter M. , Harra L. K. , Hassler D. M. , Hirzberger J. , Howard R. A. , Hurford G. , Kleint L. , Kolleck M. , Krucker S. , Lagg A. , Landini F. , Long D. M. , Lefort J. , Lodiot S. , Mampaey B. , Maloney S. , Marliani F. , Martinez-Pillet V. , McMullin D. R. , Müller D. , Nicolini G. , Orozco Suarez D. , Pacros A. , Pancrazzi M. , Parenti S. , Peter H. , Philippon A. , Plunkett S. , Rich N. , Rochus P. , Rouillard A. , Romoli M. , Sanchez L. , Schühle U. , Sidher S. , Solanki S. K. , Spadaro D. , St Cyr O. C. , Straus T. , Tanco I. , Teriaca L. , Thompson W. T. , del Toro Iniesta J. C. , Verbeeck C. , Vourlidas A. , Watson C. , Wiegelmann T. , Williams D. , Woch J. , Zhukov A. N. , Zouganelis I. 
Published: January 2020

Context.To meet the scientific objectives of the mission, the Solar Orbiter spacecraft carries a suite of in-situ (IS) and remote sensing (RS) instruments designed for joint operations with inter-instrument communication capabilities. Indeed, previous missions have shown that the Sun (imaged by the RS instruments) and the heliosphere (mainly sampled by the IS instruments) should be considered as an integrated system rather than separate entities. Many of the advances expected from Solar Orbiter rely on this synergistic approach between IS and RS measurements.Aims.Many aspects of hardware development, integration, testing, and operations are common to two or more RS instruments. In this paper, we describe the coordination effort initiated from the early mission phases by the Remote Sensing Working Group. We review the scientific goals and challenges, and give an overview of the technical solutions devised to successfully operate these instruments together.Methods.A major constraint for the RS instruments is the limited telemetry (TM) bandwidth of the Solar Orbiter deep-space mission compared to missions in Earth orbit. Hence, many of the strategies developed to maximise the scientific return from these instruments revolve around the optimisation of TM usage, relying for example on onboard autonomy for data processing, compression, and selection for downlink. The planning process itself has been optimised to alleviate the dynamic nature of the targets, and an inter-instrument communication scheme has been implemented which can be used to autonomously alter the observing modes. We also outline the plans for in-flight cross-calibration, which will be essential to the joint data reduction and analysis.Results.The RS instrument package on Solar Orbiter will carry out comprehensive measurements from the solar interior to the inner heliosphere. Thanks to the close coordination between the instrument teams and the European Space Agency, several challenges specific to the RS suite were identified and addressed in a timely manner.
Close galaxy pairs with accurate photometric redshifts
Authors: Rodriguez Facundo , Gonzalez Elizabeth Johana , O’Mill Ana Laura , Gaztañaga Enrique , Fosalba Pablo , Lambas Diego García , Mezcua Mar , Siudek Małgorzata 
Published: January 2020

Context.Studies of galaxy pairs can provide valuable information to jointly understand the formation and evolution of galaxies and galaxy groups. Consequently, taking the new high-precision photo-zsurveys into account, it is important to have reliable and tested methods that allow us to properly identify these systems and estimate their total masses and other properties.Aims.In view of the forthcoming Physics of the Accelerating Universe Survey (PAUS), we propose and evaluate the performance of an identification algorithm of projected close isolated galaxy pairs. We expect that the photometrically selected systems can adequately reproduce the observational properties and the inferred lensing mass–luminosity relation of a pair of truly bound galaxies that are hosted by the same dark matter halo.Methods.We developed an identification algorithm that considers the projected distance between the galaxies, the projected velocity difference, and an isolation criterion in order to restrict the sample to isolated systems. We applied our identification algorithm using a mock galaxy catalog that mimics the features of PAUS. To evaluate the feasibility of our pair finder, we compared the identified photometric samples with a test sample that considers that both members are included in the same halo. Taking advantage of the lensing properties provided by the mock catalog, we also applied a weak-lensing analysis to determine the mass of the selected systems.Results.Photometrically selected samples tend to show high purity values, but tend to misidentify truly bounded pairs as the photometric redshift errors increase. Nevertheless, overall properties such as the luminosity and mass distributions are successfully reproduced. We also accurately reproduce the lensing mass–luminosity relation as expected for galaxy pairs located in the same halo.
Herds on green meadows: the decarbonization of institutional portfolios
Authors: Benz Lukas , Jacob Andrea , Paulus Stefan , Wilkens Marco 
Published: January 2020

AbstractWe analyze an emerging sustainable trend in asset management: the decarbonization of institutional portfolios. By using broad institutional ownership data, we show that investors exhibit herding behavior in the sense of decarbonization. They are inclined to follow their own or other investors’ buys in green stocks and sales in brown stocks over adjacent quarters. Beyond that, we find that Hedge Funds as well as Investment Advisors lead the herd by executing trades in the sense of decarbonization. This is in line with expectations that sophisticated investors, who integrate environmental aspects into their investment decision process, are able to attract imitators. For the aspired achievement of market-wide decarbonization, investors leading the herd should be encouraged to further decarbonize their portfolios in order to trigger follow-up trades.
Dysregulation of TLR9 in neonates leads to fatal inflammatory disease driven by IFN-γ
Authors: Stanbery Alison G. , Newman Zachary R. , Barton Gregory M. 
Published: January 2020

Significance
Toll-like receptors (TLRs) sense and respond to foreign nucleic acids, but this specificity raises the risk of inappropriate responses to self-nucleic acids, leading to autoimmune diseases. Limiting TLR9 activation to endosomes is thought to reduce recognition of self-DNA. To test the importance of this compartmentalized activation for immune tolerance, we developed mice with inducible expression of a mutated TLR9 that bypasses the requirement for endosomal activation. While induction of expression in adults resulted in rather mild disease, expression during development resulted in neonatal fatality dependent on type II interferon (IFN) signaling and driven by macrophages and IFN-γ–producing natural killer cells. This study uses a new model to reveal unique aspects of TLR9-driven inflammatory disease, especially early in life.
Fast-freezing kinetics inside a droplet impacting on a cold surface
Authors: Kant Pallav , Koldeweij Robin B. J. , Harth Kirsten , van Limbeek Michiel A. J. , Lohse Detlef 
Published: January 2020

Significance
From critically affecting the performance of an aircraft to droplet-based additive manufacturing, the solidification of impacting droplets influences a wide range of industrial applications; thus, a deeper fundamental understanding of the solidification of an impacting droplet is necessary. In this work, we reveal and rationalize a peculiar freezing morphology originating from the complex interplay between the droplet-scale hydrodynamics and phase-transition effects at sufficiently high substrate undercooling. The direct visualization of different freezing morphologies only became possible as we adopt an optical technique (TIR) in the context of freezing. This technique can be employed in more complex situations, such as solidification of an impacting droplet on liquid-infused or patterned surfaces, which potentially can influence many industrial processes.
Combinatorial protein–protein interactions on a polymerizing scaffold
Authors: Ortiz-Muñoz Andrés , Medina-Abarca Héctor F. , Fontana Walter 
Published: January 2020

Significance
Scaffold proteins play an important role in the control and evolution of cellular signaling processes by brokering interactions among docking proteins. In recent years it has become apparent that many scaffolds can form oligomers. We explore theoretically the combinatorial impact of scaffold polymerization on promoting interactions. It is well known that increasing scaffold abundance first expands opportunities for ligand interaction but then collapses them as ligands become separated on different scaffold instances. The polymerizing system stands out by significantly heightening interaction possibilities in the promoting phase and considerably mitigating their collapse. While the qualitative behavior of the system is robust, parameter changes—achievable through the very processes the system mediates—can considerably sculpt its quantitative behavior.
Theory of the strange metal Sr
3
Ru
2
O
7
Authors: Mousatov Connie H. , Berg Erez , Hartnoll Sean A. 
Published: January 2020

Significance
The behavior of “strange metals” has eluded theoretical understanding for some time. It has remained unclear whether strange metals are fundamentally novel forms of matter or whether some unidentified variant of well-understood physics is at work. We show how the behavior of strontium ruthenate, a widely studied strange metal, follows in detail from well-established electronic properties. Specifically, strontium ruthenate contains “hot” electrons that are less quantum mechanical than the other “cold” electrons. A scattering process in which a cold electron becomes hot after colliding with a second cold electron is unusually strong, because the hot electrons are not subject to the Pauli exclusion principle. This fact is seen to underpin the strange metallicity of strontium ruthenate.