bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Mass Classification on a Highly Variable Arctic Shelf Region: Origin of Laptev Sea Water Masses and Implications for the Nutrient Budget
Authors: Bauch D. , Cherniavskaia E. 
Published: February 2018

AbstractLarge gradients and inter annual variations on the Laptev Sea shelf prevent the use of uniform property ranges for a classification of major water masses. The central Laptev Sea is dominated by predominantly marine waters, locally formed polynya waters and riverine summer surface waters. Marine waters enter the central Laptev Sea from the northwestern Laptev Sea shelf and originate from the Kara Sea or the Arctic Ocean halocline. Local polynya waters are formed in the Laptev Sea coastal polynyas. Riverine summer surface waters are formed from Lena river discharge and local melt. We use a principal component analysis (PCA) in order to assess the distribution and importance of water masses within the Laptev Sea. This mathematical method is applied to hydro‐chemical summer data sets from the Laptev Sea from five years and allows to define water types based on objective and statistically significant criteria. We argue that the PCA‐derived water types are consistent with the Laptev Sea hydrography and indeed represent the major water masses on the central Laptev Sea shelf. Budgets estimated for the thus defined major Laptev Sea water masses indicate that freshwater inflow from the western Laptev Sea is about half or in the same order of magnitude as freshwater stored in locally formed polynya waters. Imported water dominates the nutrient budget in the central Laptev Sea; and only in years with enhanced local polynya activity is the nutrient budget of the locally formed water in the same order as imported nutrients.
The Climatology of Low‐Level Jet in Beijing and Guangzhou, China
Authors: Miao Yucong , Guo Jianping , Liu Shuhua , Wei Wei , Zhang Gen , Lin Yanluan , Zhai Panmao 
Published: February 2018

AbstractThe important roles of low‐level jet (LLJ) in transport of heat, moisture, and pollutants have long been recognized. However, partly due to the lack of long‐term observations, the characteristics of LLJs in Beijing and Guangzhou have not been well understood. Using long‐term wind profiler observations and numerical simulations, the basic climatological characteristics of LLJ in Beijing and Guangzhou were documented, and their relationships with large‐ and local‐scale forcings were investigated. The occurrence frequencies of LLJ in both megacities approximately exhibit a bimodal distribution during an annual cycle. In terms of the seasonality, the LLJs in Beijing occur more often in spring and winter, and those in Guangzhou appear more frequently from October to December and from February to April. Pronounced diurnal variations of LLJ are found in Beijing, where most LLJs occurred during the nighttime, and the diurnal variations of LLJ in Guangzhou are less prominent. Favorable synoptic conditions for LLJ formations in Beijing are those having a southwest‐northeast or southeast‐northwest pressure gradient across Beijing. Dominant synoptic patterns associated with LLJs in Guangzhou are those having a low‐pressure or high‐pressure system to the northwest. Overall, the LLJs are primarily induced by synoptic forcings and modulated by the diurnal evolution of planetary boundary layer. The key findings from this study provide us a better understanding of the LLJs in these highly populated regions.
Optimizing Precipitation Thresholds for Best Correlation Between Dry Lightning and Wildfires
Authors: Vant‐Hull Brian , Thompson Tollisha , Koshak William 
Published: February 2018

AbstractThis work examines how to adjust the definition of “dry lightning” in order to optimize the correlation between dry lightning flash count and the climatology of large (>400 km2) lightning‐ignited wildfires over the contiguous United States (CONUS). The National Lightning Detection Network™ and National Centers for Environmental Prediction Stage IV radar‐based, gauge‐adjusted precipitation data are used to form climatic data sets. For a 13 year analysis period over CONUS, a correlation of 0.88 is found between annual totals of wildfires and dry lightning. This optimal correlation is found by defining dry lightning as follows: on a 0.1° hourly grid, a precipitation threshold of no more than 0.3 mm may accumulate during any hour over a period of 3–4 days preceding the flash. Regional optimized definitions vary. When annual totals are analyzed as done here, no clear advantage is found by weighting positive polarity cloud‐to‐ground (+CG) lightning differently than –CG lightning. The high variability of dry lightning relative to the precipitation and lightning from which it is derived suggests it would be an independent and useful climate indicator.
Estimation of Turbulent Heat Fluxes by Assimilation of Land Surface Temperature Observations From GOES Satellites Into an Ensemble Kalman Smoother Framework
Authors: Xu Tongren , Bateni S. M. , Neale C. M. U. , Auligne T. , Liu Shaomin 
Published: February 2018

AbstractIn different studies, land surface temperature (LST) observations have been assimilated into the variational data assimilation (VDA) approaches to estimate turbulent heat fluxes. The VDA methods yield accurate turbulent heat fluxes, but they need an adjoint model, which is difficult to derive and code. They also cannot directly calculate the uncertainty of their estimates. To overcome the abovementioned drawbacks, this study assimilates LST data from Geostationary Operational Environmental Satellite into the ensemble Kalman smoother (EnKS) data assimilation system to estimate turbulent heat fluxes. EnKS does not need to derive the adjoint term and directly generates statistical information on the accuracy of its predictions. It uses the heat diffusion equation to simulate LST. EnKS with the state augmentation approach finds the optimal values for the unknown parameters (i.e., evaporative fraction and neutral bulk heat transfer coefficient, CHN) by minimizing the misfit between LST observations from Geostationary Operational Environmental Satellite and LST estimations from the heat diffusion equation. The augmented EnKS scheme is tested over six Ameriflux sites with a wide range of hydrological and vegetative conditions. The results show that EnKS can predict not only the model parameters and turbulent heat fluxes but also their uncertainties over a variety of land surface conditions. Compared to the variational method, EnKS yields suboptimal turbulent heat fluxes. However, suboptimality of EnKS is small, and its results are comparable to those of the VDA method. Overall, EnKS is a feasible and reliable method for estimation of turbulent heat fluxes.
Coupled Retrieval of Liquid Water Cloud and Above‐Cloud Aerosol Properties Using the Airborne Multiangle SpectroPolarimetric Imager (AirMSPI)
Authors: Xu Feng , van Harten Gerard , Diner David J. , Davis Anthony B. , Seidel Felix C. , Rheingans Brian , Tosca Mika , Alexandrov Mikhail D. , Cairns Brian , Ferrare Richard A. , Burton Sharon P. , Fenn Marta A. , Hostetler Chris A. , Wood Robert , Redemann Jens 
Published: February 2018

AbstractAn optimization algorithm is developed to retrieve liquid water cloud properties including cloud optical depth (COD), droplet size distribution and cloud top height (CTH), and above‐cloud aerosol properties including aerosol optical depth (AOD), single‐scattering albedo, and microphysical properties from sweep‐mode observations by Jet Propulsion Laboratory's Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) instrument. The retrieval is composed of three major steps: (1) initial estimate of the mean droplet size distribution across the entire image of 80–100 km along track by 10–25 km across track from polarimetric cloudbow observations, (2) coupled retrieval of image‐scale cloud and above‐cloud aerosol properties by fitting the polarimetric data at all observation angles, and (3) iterative retrieval of 1‐D radiative transfer‐based COD and droplet size distribution at pixel scale (25 m) by establishing relationships between COD and droplet size and fitting the total radiance measurements. Our retrieval is tested using 134 AirMSPI data sets acquired during the National Aeronautics and Space Administration (NASA) field campaign ObseRvations of Aerosols above CLouds and their intEractionS. The retrieved above‐cloud AOD and CTH are compared to coincident HSRL‐2 (HSRL‐2, NASA Langley Research Center) data, and COD and droplet size distribution parameters (effective radius reff and effective variance veff) are compared to coincident Research Scanning Polarimeter (RSP) (NASA Goddard Institute for Space Studies) data. Mean absolute differences between AirMSPI and HSRL‐2 retrievals of above‐cloud AOD at 532 nm and CTH are 0.03 and <0.5 km, respectively. At RSP's footprint scale (~ 323 m), mean absolute differences between RSP and AirMSPI retrievals of COD, reff, and veff in the cloudbow area are 2.33, 0.69 μm, and 0.020, respectively. Neglect of smoke aerosols above cloud leads to an underestimate of image‐averaged COD by ~15%.
Simulation of Changes in the Near‐Surface Soil Freeze/Thaw Cycle Using CLM4.5 With Four Atmospheric Forcing Data Sets
Authors: Guo Donglin , Wang Aihui , Li Duo , Hua Wei 
Published: February 2018

AbstractChange in the near‐surface soil freeze/thaw cycle is critical for assessments of hydrological activity, ecosystems, and climate change. Previous studies investigated the near‐surface soil freeze/thaw cycle change mostly based on in situ observations and satellite monitoring. Here numerical simulation method is tested to estimate the long‐term change in the near‐surface soil freeze/thaw cycle in response to recent climate warming for its application to predictions. Four simulations are performed at 0.5° × 0.5° resolution from 1979 to 2009 using the Community Land Model version 4.5, each driven by one of the four atmospheric forcing data sets (i.e., one default Climate Research Unit‐National Centers for Environmental Prediction [CRUNCEP] and three newly developed Modern Era Retrospective‐Analysis for Research and Applications, Climate Forecast System Reanalysis, and European Centre for Medium‐Range Weather Forecasts Reanalysis Interim). The observations from 299 weather stations in both Russia and China are employed to validate the simulated results. The results show that all simulations reasonably reproduce the observed variations in the ground temperature, the freeze start and end dates, and the freeze duration (the correlation coefficients range from 0.47 to 0.99, and the Nash‐Sutcliffe efficiencies range from 0.19 to 0.98). Part of the simulations also exactly simulate the trends of the ground temperature, the freeze start and end dates, and the freeze duration. Of the four simulations, the results from the simulation using the CRUNCEP data set show the best overall agreement with the in situ observations, indicating that the CRUNCEP data set could be preferentially considered as the basic atmospheric forcing data set for future prediction. The simulated area‐averaged annual freeze duration shortened by 8.03 days on average from 1979 to 2009, with an uncertainty (one standard deviation) of 0.67 days caused by the different atmospheric forcing data sets. These results address the performance of numerical model in simulating the long‐term changes in the near‐surface soil freeze/thaw cycle and the role of different atmospheric forcing data sets in the simulation, which are useful for the prediction of future freeze/thaw dynamics.
Nitrogen Fixation Inputs in Pasture and Early Successional Forest in the Brazilian Amazon Region: Evidence From a Claybox Mesocosm Study
Authors: Davidson Eric A. , Markewitz Daniel , de O. Figueiredo Ricardo , de Camargo Plínio B. 
Published: February 2018

AbstractThe role of biological nitrogen fixation (BNF) during secondary forest succession and in tropical pastures has been investigated and debated for several decades. Here we present results of a replicated experimental study in a degraded cattle pasture of eastern Amazonia using mass balance and a 15N tracer in lined soil pit mesocosms with three treatments: (1) plant‐free control plots, (2) pasture grass Brachiaria brizantha, and (3) regrowth of early successional secondary forest species. Accumulation of N in grass biomass slightly exceeded estimates of net N mineralization from the plant‐free control plots but was within the margin of error, so inputs of BNF may not have been needed. In contrast, the secondary forest vegetation accumulated about 3 times as much biomass N annually as the net N mineralization estimate, suggesting at least some role for BNF. Based on isotopic and mass measurements of N‐fixing species, BNF was estimated to contribute at least 27 ± 3% of mean annual plant uptake in the secondary forest regrowth vegetation plots. Although BNF is probably important for recuperation of tropical secondary forests following land use change, the majority of the N taken up by both grasses and secondary forest regrowth arose from mineralization of the stocks of soil N.
Investigation of the Fire Radiative Energy Biomass Combustion Coefficient: A Comparison of Polar and Geostationary Satellite Retrievals Over the Conterminous United States
Authors: Li Fangjun , Zhang Xiaoyang , Kondragunta Shobha , Roy David P. 
Published: February 2018

AbstractBiomass burning substantially contributes to atmospheric aerosol and greenhouse gas emissions that influence climate and air quality. Fire radiative energy (FRE) (units: MJ) has been demonstrated to be linearly related to biomass consumption (units: kg) with potential for improving biomass burning emission estimation. The scalar constant, termed herein as the FRE biomass combustion coefficient (FBCC) (units: kg/MJ), which converts FRE to biomass consumption, has been estimated using field and laboratory experiments, varying from 0.368 to 0.453 kg/MJ. However, quite different FBCC values, especially for satellite‐based approaches, have been reported. This study investigated the FBCC with respect to 445 wildfires that occurred from 2011 to 2012 across the Conterminous United States (CONUS) considering both polar‐orbiting and geostationary satellite data. The FBCC was derived by comparing satellite FRE estimates with biomass consumption for the CONUS. FRE was estimated using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Geostationary Operational Environmental Satellite (GOES); biomass consumption was estimated using Landsat‐derived burned areas with fuel loadings from the Fuel Characteristic Classification System and using combustion completeness parameterized by Landsat burn severity and Fuel Characteristic Classification System fuelbed type. The reported results confirm the linearity of the empirical relationship between FRE and biomass consumption for wildfires. The CONUS FBCC was 0.374 kg/MJ for GOES FRE, 0.266 kg/MJ for MODIS FRE, and 0.320 kg/MJ considering both GOES and MODIS FRE. Limited sensitivity analyses, comparing MODIS and GOES FRE with biomass consumption estimated in three different ways, indicated that the FBCC varied from 0.301 to 0.458 kg/MJ.
The GFDL Global Atmosphere and Land Model AM4.0/LM4.0: 2. Model Description, Sensitivity Studies, and Tuning Strategies
Authors: Zhao M. , Golaz J.‐C. , Held I. M. , Guo H. , Balaji V. , Benson R. , Chen J.‐H. , Chen X. , Donner L. J. , Dunne J. P. , Dunne K. , Durachta J. , Fan S.‐M. , Freidenreich S. M. , Garner S. T. , Ginoux P. , Harris L. M. , Horowitz L. W. , Krasting J. P. , Langenhorst A. R. , Liang Z. , Lin P. , Lin S.‐J. , Malyshev S. L. , Mason E. , Milly P. C. D. , Ming Y. , Naik V. , Paulot F. , Paynter D. , Phillipps P. , Radhakrishnan A. , Ramaswamy V. , Robinson T. , Schwarzkopf D. , Seman C. J. , Shevliakova E. , Shen Z. , Shin H. , Silvers L. G. , Wilson J. R. , Winton M. , Wittenberg A. T. , Wyman B. , Xiang B. 
Published: February 2018

AbstractIn Part 2 of this two‐part paper, documentation is provided of key aspects of a version of the AM4.0/LM4.0 atmosphere/land model that will serve as a base for a new set of climate and Earth system models (CM4 and ESM4) under development at NOAA's Geophysical Fluid Dynamics Laboratory (GFDL). The quality of the simulation in AMIP (Atmospheric Model Intercomparison Project) mode has been provided in Part 1. Part 2 provides documentation of key components and some sensitivities to choices of model formulation and values of parameters, highlighting the convection parameterization and orographic gravity wave drag. The approach taken to tune the model's clouds to observations is a particular focal point. Care is taken to describe the extent to which aerosol effective forcing and Cess sensitivity have been tuned through the model development process, both of which are relevant to the ability of the model to simulate the evolution of temperatures over the last century when coupled to an ocean model.
Polyphased Inversions of an Intracontinental Rift: Case Study of the Marrakech High Atlas, Morocco
Authors: Leprêtre R. , Missenard Y. , Barbarand J. , Gautheron C. , Jouvie I. , Saddiqi O. 
Published: February 2018

AbstractThe High and Middle Atlas intraplate belts in Morocco correspond to Mesozoic rifted basins inverted during the Cenozoic during Africa/Eurasia convergence. The Marrakech High Atlas lies at a key location between Atlantic and Tethyan influences during the Mesozoic rifting phase but represents today high reliefs. Age and style of deformation and the mechanisms underlying the Cenozoic inversion are nevertheless still debated. To solve this issue, we produced new low‐temperature thermochronology data (fission track and [U‐Th]/He on apatite). Two cross sections were investigated in the western and eastern Marrakech High Atlas. Results of inverse modeling allow recognizing five cooling events attributed to erosion since Early Jurassic. Apart from a first erosional event from Middle/Late Jurassic to Early Cretaceous, four stages can be related to the convergence processes between Africa and Europe since the Late Cretaceous. Our data and thermal modeling results suggest that the inversion processes are guided at first order by the fault network inherited from the rifting episodes. The sedimentary cover and the Neogene lithospheric thinning produced a significant thermal weakening that facilitated the inversion of this ancient rift. Our data show that the Marrakech High Atlas has been behaving as a giant pop‐up since the beginning of Cenozoic inversion stages.
Centimeter‐Height 3D Printing with Femtosecond Laser Two‐Photon Polymerization
Authors: Chu Wei , Tan Yuanxin , Wang Peng , Xu Jian , Li Wenbo , Qi Jia , Cheng Ya 
Published: February 2018

AbstractNowadays 3D printing has been widely used for producing geometrically complex 3D structures from a broad range of materials such as ceramics, metals, polymers and semiconductors. Although it has been demonstrated that a fabrication resolution as high as ≈100 nm can be achieved in 3D printing based on two‐photon polymerization (TPP), the end product height of TPP is typically on millimeter scale limited by the short working distance of high‐numerical‐aperture focal lens. Herein, a method based on simultaneous spatiotemporal focusing of the femtosecond laser pulses is presented, which enables fabricating centimeter‐height 3D structures of fine features with TPP. An isotropic spatial resolution is also demonstrated, which can be continuously tuned in the range of ≈10–40 µm by only varying the power of femtosecond laser, making this technique extremely flexible and easy to implement. Several Chinese guardian lions of a maximum height of 0.6 cm and a Terra Cotta Warrior of a height of 1.3 cm are fabricated using this method.
Surface‐Plasmon‐Polariton Diode by Asymmetric Plano‐Concave Nanocavities
Authors: Liu Feifei , Zhang Xinping 
Published: February 2018

AbstractHigh‐efficiency and direction‐controllable launching of surface plasmon polaritons (SPPs) is highly desired in plasmonic devices and photonic circuits. Here, a heteroplasmonic device is reported consisting of an array of asymmetric nanocavities with each nanocavity constructed by an asymmetric Ag nanoshell (AgNS) and a planar gold film (AuFilm). A photoresist grating is used both as a template for fabricating the AgNS array and as the dielectric filling medium of the nanocavities. Interaction between localized surface plasmon resonance in the asymmetric AgNSs and SPPs in the AuFilm has enhanced the propagating surface modes along the gold film. A phase modulation induced by the asymmetry and interference between the SPP modes have been the main physics supporting the directional propagation of the surface waves or the in‐plane optical diode effect at normal incidence. The SPP diode works in different directions at different wavelengths, which can be controlled by adjusting the asymmetry of the AgNSs.
Aqueous α‐Arylation of Mono‐ and Diarylethanone Enolates at Low Catalyst Loading
Authors: Astarloa Iratxe , SanMartin Raul , Herrero María Teresa , Domínguez Esther 
Published: February 2018

AbstractAcetophenone and deoxybenzoin derivatives are selectively α‐arylated using a combination of very small amounts of palladium acetate and diphenylphosphine oxide as catalyst system and water as the only solvent. Target di‐ and triarylethanones are isolated virtually free of metal residues, and the reaction is amenable to gram‐scale. A mechanistic proposal based on TEM images, poisoning experiments, kinetic plot and ESI‐MS spectrometry is also provided.magnified image
Slow‐Release Formulation of Cowpea Mosaic Virus for In Situ Vaccine Delivery to Treat Ovarian Cancer
Authors: Czapar Anna E. , Tiu Brylee David B. , Veliz Frank A. , Pokorski Jonathan K. , Steinmetz Nicole F. 
Published: February 2018

AbstractThe plant viral nanoparticle cowpea mosaic virus (CPMV) is shown to be an effective immunotherapy for ovarian cancer when administered as in situ vaccine weekly, directly into the intraperitoneal (IP) space in mice with disseminated tumors. While the antitumor efficacy is promising, the required frequency of administration may pose challenges for clinical implementation. To overcome this, a slow release formulation is developed. CPMV and polyamidoamine generation 4 dendrimer form aggregates (CPMV‐G4) based on electrostatic interactions and as a function of salt concentration, allowing for tailoring of aggregate size and release of CPMV. The antitumor efficacy of a single administration of CPMV‐G4 is compared to weekly administration of soluble CPMV in a mouse model of peritoneal ovarian cancer and found to be as effective at reducing disease burden as more frequent administrations of soluble CPMV; a single injection of soluble CPMV, does not significantly slow cancer development. The ability of CPMV‐G4 to control tumor growth following a single injection is likely due to the continued presence of CPMV in the IP space leading to prolonged immune stimulation. This enhanced retention of CPMV and its antitumor efficacy demonstrates the potential for viral–dendrimer hybrids to be used for delayed release applications.