bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wintertime Nonbrightband Rain in California and Oregon during CALJET and PACJET: Geographic, Interannual, and Synoptic Variability
Authors: Neiman Paul J. , Wick Gary A. , Ralph F. Martin , Martner Brooks E. , White Allen B. , Kingsmill David E. 
Published: June 2005

Abstract
An objective algorithm presented in White et al. was applied to vertically pointing S-band (S-PROF) radar data recorded at four sites in northern California and western Oregon during four winters to assess the geographic, interannual, and synoptic variability of stratiform nonbrightband (NBB) rain in landfalling winter storms. NBB rain typically fell in a shallow layer residing beneath the melting level (&lt;∼3.5 km MSL), whereas rainfall possessing a brightband (BB) was usually associated with deeper echoes (&gt;∼6 km MSL). The shallow NBB echo tops often resided beneath the coverage of the operational Weather Surveillance Radar-1988 Doppler (WSR-88D) scanning radars yet were still capable of producing flooding rains.
NBB rain contributed significantly to the total winter-season rainfall at each of the four geographically distinct sites (i.e., 18%–35% of the winter-season rain totals). In addition, the rainfall observed at the coastal mountain site near Cazadero, California (CZD), during each of four winters was composed of a significant percentage of NBB rain (18%–50%); substantial NBB rainfall occurred regardless of the phase of the El Niño–Southern Oscillation (which ranged from strong El Niño to moderate La Niña conditions). Clearly, NBB rain occurs more widely and commonly in California and Oregon than can be inferred from the single-winter, single-site study of White et al.
Composite NCEP–NCAR reanalysis maps and Geostationary Operational Environment Satellite (GOES) cloud-top temperature data were examined to evaluate the synoptic conditions that characterize periods of NBB precipitation observed at CZD and how they differ from periods with bright bands. The composites indicate that both rain types were tied generally to landfalling polar-cold-frontal systems. However, synoptic conditions favoring BB rain exhibited notable distinctions from those characterizing NBB periods. This included key differences in the position of the composite 300-mb jet stream and underlying cold front with respect to CZD, as well as notable differences in the intensity of the 500-mb shortwave trough offshore of CZD. The suite of BB composites exhibited dynamically consistent synoptic-scale characteristics that yielded stronger and deeper ascent over CZD than for the typically shallower NBB rain, consistent with the GOES satellite composites that showed 20-K warmer (2.3-km shallower) cloud tops for NBB rain. Composite soundings for both rain types possessed low-level potential instability, but the NBB sounding was warmer and moister with stronger low-level upslope flow, thus implying that orographically forced rainfall is enhanced during NBB conditions.
Forecast Model Bias Correction in Ocean Data Assimilation
Authors: Chepurin Gennady A. , Carton James A. , Dee Dick 
Published: June 2005

Abstract
Numerical models of ocean circulation are subject to systematic errors resulting from errors in model physics, numerics, inaccurately specified initial conditions, and errors in surface forcing. In addition to a time-mean component, the systematic errors include components that are time varying, which could result, for example, from inaccuracies in the time-varying forcing. Despite their importance, most assimilation algorithms incorrectly assume that the forecast model is unbiased. In this paper the authors characterize the bias for a current assimilation scheme in the tropical Pacific. The characterization is used to show how relatively simple empirical bias forecast models may be used in a two-stage bias correction procedure to improve the quality of the analysis.
Contraction Rate and Its Relationship to Frontogenesis, the Lyapunov Exponent, Fluid Trapping, and Airstream Boundaries
Authors: Cohen Robert A. , Schultz David M. 
Published: June 2005

Abstract
Although a kinematic framework for diagnosing frontogenesis exists in the form of the Petterssen frontogenesis function and its vector generalization, a similar framework for diagnosing airstream boundaries (e.g., drylines, lee troughs) has not been constructed. This paper presents such a framework, beginning with a kinematic expression for the rate of change of the separation vector between two adjacent air parcels. The maximum growth rate of the separation vector is called the instantaneous dilatation rate and its orientation is called the axis of dilatation. Similarly, a maximum decay rate is called the instantaneous contraction rate and its orientation is called the axis of contraction. These expressions are related to the vector frontogenesis function, in that the growth rate of the separation vector corresponds with the scalar frontogenesis function, and the rotation rate of the separation vector corresponds with the rotational component of the vector frontogenesis function.
Because vorticity can rotate air-parcel pairs out of regions of deformation, the instantaneous dilatation and contraction rates and axes may not be appropriate diagnostics of airstream boundaries for fluid flows in general. Rather, the growth rate and orientation of an airstream boundary may correspond better to the so-called asymptotic contraction rate and the asymptotic axis of dilatation, respectively. Expressions for the asymptotic dilatation and contraction rates, as well as their orientations, the asymptotic dilatation and contraction axes, are derived. The asymptotic dilatation rate is related to the Lyapunov exponent for the flow. In addition, a fluid-trapping diagnostic is derived to distinguish among adjacent parcels being pulled apart, being pushed together, or trapped in an eddy. Finally, these diagnostics are applied to simple, idealized, steady-state flows and a nonsteady idealized vortex in nondivergent, diffluent flow to show their utility for determining the character of air-parcel trajectories and airstream boundaries.
Applying Horizontal Diffusion on Pressure Surface to Mesoscale Models on Terrain-Following Coordinates
Authors: Juang Hann-Ming Henry , Lee Ching-Teng , Zhang Yongxin , Song Yucheng , Wu Ming-Chin , Chen Yi-Leng , Kodama Kevin , Chen Shyh-Chin 
Published: June 2005

Abstract
The National Centers for Environmental Prediction regional spectral model and mesoscale spectral model (NCEP RSM/MSM) use a spectral computation on perturbation. The perturbation is defined as a deviation between RSM/MSM forecast value and their outer model or analysis value on model sigma-coordinate surfaces. The horizontal diffusion used in the models applies perturbation diffusion in spectral space on model sigma-coordinate surfaces. However, because of the large difference between RSM/MSM and their outer model or analysis terrains, the perturbation on sigma surfaces could be large over steep mountain areas as horizontal resolution increases. This large perturbation could introduce systematical error due to artificial vertical mixing from horizontal diffusion on sigma surface for variables with strong vertical stratification, such as temperature and humidity. This nonnegligible error would eventually ruin the forecast and simulation results over mountain areas in high-resolution modeling.
To avoid the erroneous vertical mixing on the systematic perturbation, a coordinate transformation is applied in deriving a horizontal diffusion on pressure surface from the variables provided on terrain-following sigma coordinates. Three cases are selected to illustrate the impact of the horizontal diffusion on pressure surfaces, which reduces or eliminates numerical errors of mesoscale modeling over mountain areas. These cases address concerns from all aspects, including unstable and stable synoptic conditions, moist and dry atmospheric settings, weather and climate integrations, hydrostatic and nonhydrostatic modeling, and island and continental orography.
After implementing the horizontal diffusion on pressure surfaces for temperature and humidity, the results show better rainfall and flow pattern simulations when compared to observations. Horizontal diffusion corrects the warming, moistening, excessive rainfall, and convergent flow patterns around high mountains under unstable and moist synoptic conditions and corrects the cooling, drying, and divergent flow patterns under stable and dry synoptic settings.
Diagnostic Comparison of Meteorological Analyses during the 2002 Antarctic Winter
Authors: Manney Gloria L. , Allen Douglas R. , Krüger Kirstin , Naujokat Barbara , Santee Michelle L. , Sabutis Joseph L. , Pawson Steven , Swinbank Richard , Randall Cora E. , Simmons Adrian J. , Long Craig 
Published: June 2005

Abstract
Several meteorological datasets, including U.K. Met Office (MetO), European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), and NASA’s Goddard Earth Observation System (GEOS-4) analyses, are being used in studies of the 2002 Southern Hemisphere (SH) stratospheric winter and Antarctic major warming. Diagnostics are compared to assess how these studies may be affected by the meteorological data used. While the overall structure and evolution of temperatures, winds, and wave diagnostics in the different analyses provide a consistent picture of the large-scale dynamics of the SH 2002 winter, several significant differences may affect detailed studies. The NCEP–NCAR reanalysis (REAN) and NCEP–Department of Energy (DOE) reanalysis-2 (REAN-2) datasets are not recommended for detailed studies, especially those related to polar processing, because of lower-stratospheric temperature biases that result in underestimates of polar processing potential, and because their winds and wave diagnostics show increasing differences from other analyses between ∼30 and 10 hPa (their top level). Southern Hemisphere polar stratospheric temperatures in the ECMWF 40-Yr Re-analysis (ERA-40) show unrealistic vertical structure, so this long-term reanalysis is also unsuited for quantitative studies. The NCEP/Climate Prediction Center (CPC) objective analyses give an inferior representation of the upper-stratospheric vortex. Polar vortex transport barriers are similar in all analyses, but there is large variation in the amount, patterns, and timing of mixing, even among the operational assimilated datasets (ECMWF, MetO, and GEOS-4). The higher-resolution GEOS-4 and ECMWF assimilations provide significantly better representation of filamentation and small-scale structure than the other analyses, even when fields gridded at reduced resolution are studied. The choice of which analysis to use is most critical for detailed transport studies (including polar process modeling) and studies involving synoptic evolution in the upper stratosphere. The operational assimilated datasets are better suited for most applications than the NCEP/CPC objective analyses and the reanalysis datasets (REAN/REAN-2 and ERA-40).
A Wavelet Approach to Representing Background Error Covariances in a Limited-Area Model
Authors: Deckmyn Alex , Berre Loïk 
Published: June 2005

Abstract
The use of orthogonal wavelets for the representation of background error covariances over a limited area is studied. Each wavelet function contains both information on position and information on scale: using a diagonal correlation matrix in wavelet space thus gives the possibility of representing the local variations of correlation scale. To this end, a generalized family of orthogonal Meyer wavelets that are not restricted to dyadic domains (i.e., powers of 2) is introduced. A three-bases approach is used, which allows one to take advantage of the respective properties of the spectral, wavelet, and gridpoint spaces. While the implied local anisotropies are relatively small, the local changes in the two-dimensional length scale are rather well represented.
Poly-phase alteration history of the kaolinitized ‘Cava di Caolino’ volcanics (Lipari Island, southern Italy)
Authors: Decrée S. , Bernard A. , Yans J. , De Putter Th. 
Published: June 2005

AbstractA 65 m thick altered volcanic profile was studied in the Cava di Caolino (Lipari Island) in order to (1) identify the alteration event(s), (2) model these events, and (3) propose estimates of the degree of chemical alteration (CIA, chemical index of alteration). Two mineral parageneses were identified: one comprising silico-aluminous phases, with well crystallized kaolinite (type 1), and the other comprising sulphates, with kaolinite as fracture infilling (type 2). The geochemistry of fluids analysed from a local hot spring (40°C, pH ≈ 8) allowed modelling of the observed silico-aluminous paragenesis. A later fumarolic event is suggested to be responsible for the sulphate paragenesis. The main stage of hydrothermal alteration lasted for ~50 ky, was marked by an increase in the CIA from the protolith (~52) to the alterites (~98), and resulted in the alteration of a 65 m thick series. Such data could be used to predict the alteration of volcanic rocks around underground nuclear waste repositories.
How reliable is the K-Ar glauconite chronometer? A case study of Eocene sediments from the Isle of Wight
Authors: Clauer N. , Huggett J. M. , Hillier S. 
Published: June 2005

AbstractK-Ar ages of Eocene glauconite pellets from the Isle of Wight are related to quantified amounts of older glauconite pellets and to occurrences of detrital mica/illite particles that might have been added to synsedimentary pellets during reworking processes. Addition of older glauconite did not significantly bias the K-Ar dates, as the results most often provide the expected stratigraphic reference ages or even significantly lower ages. Alternatively, K-Ar dates significantly greater than those suggested by the stratigraphy appear to result from non-glauconized detrital mica in the pellets which is not always removable, even by high-gradient magnetic separation.Unexpected ‘old’ K-Ar glauconite ages do not result from misapplication of the method, but from inability to systematically identify and remove the `contaminant' particles from glauconite splits. Analysis of highly evolved glauconite separates is definitely appropriate for reliable isotopic age determinations, but it might not be enough for the final selection, as long-lasting diagenesis might have taken over the synsedimentary process. Much if not all depends on the separation and characterization of the separates, but also on the completion of the glauconitization process which effects cannot always be anticipated.
Synthesis and characterization of montmorillonite-type phyllosilicates in a fluoride medium
Authors: Reinholdt M. , Miehé-Brendlé J. , Delmotte L. , Le Dred R. , Tuilier M.-H. 
Published: June 2005

AbstractThe fluorine route is thoroughly investigated for the hydrothermal synthesis of montmorillonite in the Na2O-MgO-Al2O3-SiO2-H2O system. Using the optimal conditions suggested by Reinholdt et al. (2001) for the crystallization of pure montmorillonites with the formula Na2x(Al2(1-x)Mg2x☐)Si4O10(OH)2, several parameters (x, Mg content, duration of crystallization, F/Si atomic ratio, pH, nature of counterbalance cation) are varied independently from their ideal values. The products are analysed by various techniques (X-ray diffraction, thermogravimetric analysis-differential thermal analysis, 29Si, 27Al and 19F magic angle spinning-nuclear magnetic resonance). It appears that a pure montmorillonite can only be obtained within a narrow x range (0.10 ≤ x ≤ 0.20). The presence of F in the starting hydrogel and the crystallization time also have significant effects on the purity of the final products. It is shown that a small amount of fluorine is needed for the crystallization of pure montmorillonite phyllosilicates.
Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications
Authors: Khormali F. , Abtahi A. , Owliaie H. R. 
Published: June 2005

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.
Combining DLS, XRD, SEM-EDAX and EXAFS in the study of Zn(II) retention on a palygorskitic clay
Authors: Aisa C. , Alvarez-Puebla R. A. , Blasco J. , Echeverría J. C. , Garrido J. J. 
Published: June 2005

AbstractClay materials play a key role in determining the retention capacity of a soil, and are widely used in waste treatments. One of the most commonly used clays is palygorskite. The aim of this research is to determine the chemical species formed by Zn when retained in a palygorskitic clay material. Adsorption isotherm analysis is useful in studying the retention process, because it provides a macroscopic view of the retention phenomena. Complementary techniques are needed in order to study the different retention processes. Sorption isotherms of Zn on palygorskitic clay were carried out; the supernatant was analysed by means of dynamic light scattering (DLS) and the residues by using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive angle X-ray (SEM-EDAX)analysis and extended X-ray absorption fine structure (EXAFS). Isotherm analysis shows that the global retention process could be due to the sum of two separate processes, adsorption and surface precipitation via solid-solution. This is supported by DLS, which shows that ζ potential increases as the Zn(II) is retained onto clay surfaces but remains constant during the precipitation process. The XRD pattern corresponding to the Zn-clay system showed weak new peaks, probably from zincite. The microanalysis by X-ray fluorescence of several spots selected for their different electronic densities indicated that the retained Zn was randomly distributed across the clay surface. Analysis by EXAFS supports the hypothesis of retention via adsorption and solid-solution surface precipitation.
Mineralogy, chemical characteristics and stabilities of Cetylpyridinium-exchanged smectite
Authors: Koh S. M. , Song M. S. , Takagi T. 
Published: June 2005

AbstractCP (Cetylpyridinium)-exchanged smectite was manufactured by the cationic exchange reaction of Na-smectite with CP. The adsorption behaviour shows a typical L-type isotherm representing continuous and stable adsorption in excess of twice the cation exchange capacity of CP. CP-smectite shows a strong interlayer (d001) expansion to 40.2 Å when an amount of CP equivalent to 140% of the CEC is exchanged into smectite. CP-smectite is characterized by strong alkalinity (pH 9.3), low swelling (4.5 ml/2 g), low viscosity (3.9 mPa s), and strong and fast flocculation. These characteristics are in striking contrast to Na-smectite except for the alkalinity. CP-smectite shows no signs of desorption of the organic species under varying pH conditions (pH 2–12). Desorption is slight even when washed three times with DH2O (distilled water). Pyrolysis of CP-smectite begins at 250°C and ends at 400°C. These stable and persistent characteristics and the relatively low price of CP point to the likely increased use of CP-smectite as an organoclay.
The adsorption of berberine by montmorillonite and thermo-XRD analysis of the organo-clay complex
Authors: Cohen E. , Joseph T. , Lapides I. , Yariv S. 
Published: June 2005

AbstractThe adsorption of the large cationic alkaloid berberine by montmorillonite in aqueous suspensions was investigated. An adsorption isotherm of berberine and desorption isotherms of exchangeable Na+, K+, Mg2+ and Ca2+ were determined by chemical analysis of the non-adsorbed berberine and the released cations in the supernatants. The isotherms suggest that the adsorption of berberine takes place in two different types of reaction mechanism: (1) cation exchange, and (2) a secondary organophyllic adsorption. The cation exchange occurring first is followed by the secondary adsorption which is accompanied by Cl- adsorption. Monovalent cations are exchanged before the divalent cations.Samples loaded with increasing amounts of berberine were examined by X-ray diffraction at room temperature, and after gradual heating up to 420°C. The basal spacing of the loaded samples after the thermal treatment became 1.28 nm, indicating the formation of carbon in the interlayer, thus proving that the adsorbed berberine was located in the interlayer space. At room temperature the basal spacing of samples loaded with 8 and 15 mmol of berberine per 100 g of clay was 1.28–1.30 nm indicating that in the interlayer space berberine cations were lying parallel to the alumino-silicate layers. The basal spacing of a sample with 36 mmol of berberine per 100 g of clay was 1.48 nm. This spacing does not give conclusive information on the arrangement of berberine in the interlayer. The spacing of samples with 57–147 mmol of berberine per 100 g of clay was 1.59 nm, suggesting the presence of bilayers of berberine in the interlayers. During thermal dehydration, the spacing of samples with 36–73 mmol of berberine per 100 g of clay decreased, but that of samples with 105–147 mmol of berberine per 100 g of clay increased to 1.66 nm. These samples contain organophilic adsorbed berberine and it is suggested that due to the thermal treatment berberine was tilted relative to the TOT lamellae, with anhydrous Cl- between the berberine cations.
Adsorption of cetyltrimethylammonium ions on an acid-activated smectite and their thermal stability
Authors: Kooli F. , Magusin P. C. M. M. 
Published: June 2005

AbstractThe intercalation of the cationic surfactant cetyltrimethylammonium (C16TMA) into the interlayer of an acid-activated clay in the presence of different anions has been studied in detail. When Br or OH anions were used, the basal spacing increased significantly, the increase being related to the loading concentration of the surfactant solution. For intercalated compounds prepared from the hydroxide form, the basal spacing at room temperature varied from 1.6 to 3.8 nm. However, for organoclays prepared from the surfactant bromide, the basal spacing is almost loading- independent (1.9 nm). The use of hydroxide and bromide at higher pH is crucial to intercalating larger amounts of C16TMA cations and, hence, to improving the exfoliation of the silicate sheets. Magic-angle spinning 13C nuclear magnetic resonance spectroscopy indicates that the intercalated surfactants exhibit a significant degree of gauche conformation. According to in situ powder X-ray diffraction, an increase of the basal spacing to 4.08 nm is observed at intermediate temperatures of 50 to 150°C for organoclay with an initial basal spacing of 3.7 nm. At higher temperatures, decomposition of the surfactant occurs and the basal spacing decreases to ~1.4 nm.