bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipase-Catalyzed Reaction of Molecularly Pure Linear and Cyclic Poly(3-hydroxybutanoate)s: Evidence of Cyclic Polymer Formation
Authors: Osanai Yasushi , Toshima Kazunobu , Matsumura Shuichi
Published: December 2003

Molecularly pure linear and cyclic poly(3-hydroxybutanoate) [P(3HB)] polymer species were subjected to hydrolysis, transesterification and intramolecular esterification by lipase to produce two series of linear and cyclic polymer structures having higher and lower molecular weights. It was found that a cyclic polymer was produced by the lipase-catalyzed reaction of the polymer chain.
Superior Decomposition of NO over Plasma-Assisted Catalytic System Induced by Microwave
Authors: Roh Hyun-Seog , Park Yong-Ki , Park Sang-Eon
Published: December 2003

More than 99% of NO was directly decomposed into N2 and O2 without formation of N2O at space velocity of 45360 h−1 and apparent temperature of 280 °C over plasma-assisted Co3O4/Cu-ZSM-5 catalyst.
A New Method for the Synthesis of Unsymmetrical Bis-Aldols by the Samarium(II) Iodide-Mediated Aldol Reaction of Aldehydes with Aryl or Alkyl Oxiranyl Ketones
Authors: Mukaiyama Teruaki , Arai Hidehiro , Shiina Isamu
Published: December 2003

Unsymmetrical alkyl or aryl 2-hydroxy-1-(1-hydroxyalkyl)alkyl ketones (bis-aldols) were synthesized by the samarium(II) iodide-mediated aldol reaction of aldehydes with alkyl or aryl oxiranyl ketones. Bis-aldols were formed via the aldol reaction of aldehydes with samarium enolates generated by epoxy-fragmentation of oxiranyl ketones using two moles of samarium(II) iodide.
Bicyclic and Tricyclic Ladder Compounds Consisting of Two Oligosiloxane Chains Bridged by Si–Si Rungs
Authors: Kyushin Soichiro , Takahashi Masaki , Matsumoto Hideyuki
Published: December 2003

The bicyclic and tricyclic ladder compounds consisting of two oligosiloxane chains bridged by Si–Si rungs were synthesized by the condensation of 1,2-dihydroxy-1,1,2,2-tetraisopropyldisilane and 1,1,2,2-tetrachloro-1,2-diisopropyldisilane with aniline. The structures of these compounds were confirmed by X-ray crystallography.
Synthesis of Spiro[indoline-3,2′-pyrrolidine] Derivatives from β-3-Indolyl Ketone Oximes
Authors: Tanaka Kenichi , Mori Yutaka , Narasaka Koichi
Published: December 2003

Spiro[indoline-3,2′-pyrrolidine] derivatives were prepared from β-3-indolyl ketone oximes by treatment with methanesulfonyl chloride and triethylamine via the bond formation between 3-position of the indole ring and oxime nitrogen. These diazaspirocycles were readily transformed to the corresponding spiro oxindole derivatives.
Energy Structure and Photocatalytic Activity of Niobates and Tantalates Containing Sn(II) with a 5s2 Electron Configuration
Authors: Hosogi Yasuhiro , Tanabe Kentaro , Kato Hideki , Kobayashi Hisayoshi , Kudo Akihiko
Published: December 2003

SnNb2O6 (BG = 2.3 eV) containing Sn2+ with a 5s2 electron configuration showed the photocatalytic activity for H2 evolution from an aqueous methanol solution under visible light irradiation (λ > 420 nm) in the presence of a Pt cocatalyst. The energy structure calculation by the plane wave based density functional method revealed that the conduction and valence bands consisted of Nb4d and Sn5s orbitals, respectively. The valence band level consisting of the Sn5s orbitals was more negative than that consisting of O2p orbitals resulting in SnNb2O6 being responsive to visible light.
A New Amorphous Lithium-ion Conductor in the System Li2S–P2S3
Authors: Machida Nobuya , Yamamoto Hidekazu , Shigematsu Toshihiko
Published: December 2003

Amorphous solid electrolytes in the system Li2S–P2S3 were obtained in a narrow composition range at around 66.7 mol % Li2S content by a high-energy ball-milling process. The 66.7Li2S·33.3P2S3 (mol %) sample showed the highest ion conductivity of 1.1 × 10−4 S·cm−1 at room temperature among the obtained samples. Cyclic voltammetry revealed that the sample had a wide electrochemical window of about 5 V.
First Observation of the Vibrational Circular Dichroism Spectra of Synthetic Chiral Porphyrazines
Authors: Kobayashi Nagao , Fukuda Takamitsu
Published: December 2003

Vibrational circular dichroism (VCD) spectra of (R)-(−)- and (S)-(+)-camphor-substituted tetrapyrazinoporphyrazines, which show a mirror-image relationship with respect to the line of intensity = 0, were recorded as the first VCD spectra of synthetic porphyrins.
A Novel Catalyst Iron(II) Tetra(1,4-dithin)porphyrazine for Oxygenating Degradation of Organic Pollutants in Aqueous Solutions
Authors: Deng Kejian , Huang Fei , Wang Duoyuan , Peng Zhenghe , Zhou Yunhong
Published: December 2003

An efficient catalyst of the title complex (abbreviated as FePz(dtn)4) is a porphyrin-like complex, which is able to activate molecular oxygen for oxidative degradation of organic compounds in an extensive pH region without light excitation. The experiments indicated that the FePz(dtn)4/O2 system showed an excellent oxygenation capability, in which the Rhodamine B(RhB) was degraded nearly 52% in alkaline aqueous solution in the seven hours and the p-nitrobenzoic acid(NBA) could be also oxygenated nearly 85% detected by UV–vis, HPLC in the similar conditions. The degradation components of RhB and NBA were analyzed by GC–MS and IR. The mineralization rate of RhB and NBA were 12 and 11.1% after reaction for 24 h respectively.
Comparison of Mercury Removal Efficiency from a Simulated Exhaust Gas by Several Types of TiO2 under Various Light Sources
Authors: Lee Yong Gyu , Park Jin-Won , Kim Jung-Hyun , Min Byoung Ryul , Jurng Jongsoo , Kim Jinsoo , Lee Tai Gyu
Published: December 2003

A removal efficiency of vapor-phase elemental mercury by TiO2 irradiated using various light sources was investigated. The effective surface area of TiO2 for Hg adsorption and UV radiation was increased by packing the adsorption bed with mixture of TiO2 and glass beads. A rotating-type reactor was specially designed to maximize the photocatalyst’s exposure to the light source. For three types of commercially available TiO2, more than 99% of initial Hg was removed under all the light sources tested except for the blue light still achieving a Hg removal efficiency close to 85%.
Silylium Ion to Silylium Ion Rearrangement Caused by 1,3-Methyl Migration
Authors: Nakamoto Masaaki , Fukawa Tomohide , Sekiguchi Akira
Published: December 2003

One-electron oxidation of a stable tris[di-tert-butyl(methyl)silyl]silyl radical by the triphenylmethylium ion produces the corresponding silylium ion 2. However, this underwent a rapid intramolecular methyl group migration to form a more stable silylium ion 4 via a Wagner–Meerwein type rearrangement. The facile 1,3-methyl migration over the three peripheral silicon atoms in 4 was observed in NMR time scale.
Pyrene-Fused Porphyrins: Annulation Reactions of meso-Pyrenylporphyrins
Authors: Yamane Osamu , Sugiura Ken-ichi , Miyasaka Hitoshi , Nakamura Kazuya , Fujimoto Tatsuhiko , Nakamura Kazuki , Kaneda Takahiro , Sakata Yoshiteru , Yamashita Masahiro
Published: December 2003

We prepared novel pyrene-fused porphyrins via the oxidative intramolecular ring closure reactions of meso-pyrenylporphyrin. The excitation energies and the oxidation potentials of the isolated dark-colored pyrene-fused porphyrins were significantly low compared with those of the corresponding precursors.
Fabrication of Polymer Crystals/Ag Nanocomposite by Intercalation
Authors: Matsumoto Akikazu , Odani Toru
Published: December 2003

The intercalation of alkali metals into the polymer crystals of benzylammonium muconate is achieved by immersion in the corresponding alkaline aqueous solution at room temperature, followed by an ion-exchange reaction to the silver salt and subsequent photoreduction of the polymer, leading to the fabrication of a new type of nanocomposite consisting of organic polymer crystals and Ag nanoparticles.
Poly[2,7-(9-oxo-9-phosphafluorenylene)-alt-co-(1,4-arylene)]s: Phosphorus-containing π-Conjugated Polymers
Authors: Makioka Yoshikazu , Hayashi Teruyuki , Tanaka Masato
Published: December 2003

Poly[2,7-(9-oxo-9-phosphafluorenylene)-alt-co-(1,4-arylene)]s, readily prepared from 2,7-dibromo-9-oxo-9-phosphafluorenes and arylene bisboronates, behaved as extended π-conjugated polymers in the UV–vis absorption spectroscopy and displayed green-blue fluorescence with high quantum yields. Cyclic voltammetry revealed the polymers exhibited electrochromic behaviors and afforded a bandgap of ca. 2.8 eV, consistent with the value from the absorption edge.
New Conducting Polymers Based on Poly(3,4-ethylenedioxypyrrole): Synthesis, Characterization, and Properties
Authors: Kim In Tae , Lee Jung Youl , Lee Sang Woo
Published: December 2003

Solution-processible conducting polymers 1 and 2, based on 3,4-ethylenedioxypyrrole, were synthesized. A comparison of the polymers’ optical and electrical properties showed that the introduction of a vinyl group in polymer 1 produced a decrease of bandgap. This occurrence was attributed to the enhancement of the planarity of polymer 1.
Rational Synthetic Strategy. From Layered Structure to MnO2 Nanotubes
Authors: Wang Xun , Li Yadong
Published: December 2003

In this manuscript, a rational synthetic strategy from layer structure to nanotubes has been developed in the synthesis of δ-MnO2 single crystal nanotubes by employing layered α-NaMnO2 as precursors through a controlled hydrothermal intercalation process.
Synthesis and Properties of Amorphous Hole Transport Materials of Triphenylamine Based Trihydrazones
Authors: Jiang Ke Jian , Sun Ya Li , Shao Ke Feng , Yang Lian Ming
Published: December 2003

A novel class of amorphous state triphenylamine-based trihydrazones were synthesized by condensation reaction of tris(p-formylphenyl)amine with N-methyl-N-phenyl hydrazine, N,N-diphenylhydrazine, N-1-naphthyl-N-phenyl-hydrazine, and N-2-naphthyl-N-phenyl-hydrazine, respectively, and characterized using different scanning calorimetry (DSC) and cyclic voltammetry (CV).
Dynamic Covalent Chemistry in Rotaxane Synthesis. Slipping Approach to [2]Rotaxane Utilizing Reversible Cleavage–Rebondage of Trityl Thioether Linkage
Authors: Furusho Yoshio , Oku Tomoya , Rajkumar G Abraham , Takata Toshikazu
Published: December 2003

A [2]rotaxane was synthesized in a high yield from a dumbbell-shaped sec-ammonium salt having trityl thioether and 3,5-di-t-butylphenyl groups at the both ends and dibenzo-24-crown-8-ether, through the slipping, utilizing the reversible cleavage–rebondage of the trityl thioether linkage.
Novel Synthesis of Tin Dioxide Nanoribbons via a Mild Solution Approach
Authors: Ye Changhui , Fang Xiaosheng , Wang Yinhai , Xie Ting , Zhao Aiwu , Zhang Lide
Published: December 2003

Single crystalline tin dioxide nanoribbons have been synthesized in bulk quantity by a mild solution approach using cetyltrimethylammonium bromide surfactant as a soft template. The as-synthesized SnO2 nanoribbons have a length up to tens of micrometers, width of several hundred nanometers, and thickness of several tens of nanometers.
Formation of Nanocrystalline TiC by a Low-temperature Route
Authors: Shi Liang , Gu Yunle , Chen Luyang , Yang Zeheng , Ma Jianhua , Qian Yitai
Published: December 2003

Nanocrystalline cubic titanium carbide (TiC) powders were successfully synthesized at 450 °C in an autoclave by using Ti, Na, and CCl4 as the reactants. The X-ray powder diffraction pattern indicates the formation of TiC. Transmission electron microscopy images show that typical TiC crystallites are composed of nanoparticles with the average grain size of about 30 nm.
Lithium Carbonate Flux Effects on the Luminescence Properties of Europium-doped Lanthanum Oxycarbonate Phosphor
Authors: Tamura Shinji , Koyabu Kazuhiko , Masui Toshiyuki , Imanaka Nobuhito
Published: December 2003

Lithium carbonate flux was introduced in the preparation of La2O2CO3: Eu3+ oxycarbonate phosphor particles to improve the photoluminescence intensities. The flux treatment brought increasing in the crystallinity of oxycarbonate phosphor accompanying the phase transition from the two-phase mixture of tetragonal and monoclinic forms to single hexagonal phase of rare earth oxycarbonate, resulting in the increase of the emission intensity.
Adsorption of Aromatic Thiols on Gold Nanoparticle Surfaces Investigated by UV–vis Absorption Spectroscopy and Surface Enhanced Raman Scattering
Authors: Joo Sang-Woo
Published: December 2003

A UV–vis absorption spectroscopy and surface-enhanced Raman scattering (SERS) study shows that benzyl mercaptan was found to be adsorbed faster than thiophenol on gold nanoparticle surfaces at a low bulk concentration of ≈10−7 M, whereas they appeared to exhibit almost identical spectral behaviors at high concentration of ≈10−5 M.
A numerical study of the genesis of concentric eyewalls in hurricanes
Authors: Nong Shangyao , Emanuel Kerry
Published: December 2003

We use two axisymmetric numerical models to explore the dynamics of concentric eyewalls in hurricanes. The first is a simple two‐layer model using balanced dynamics and parametrized convection, while the second is a cloud‐resolving non‐hydrostatic model. In the case of the balanced model, infinitesimal disturbances amplify into secondary eyewalls provided the lower troposphere is sufficiently moist; otherwise, finite‐amplitude perturbations are necessary to initiate amplifying structures. But experiments with the full‐physics model show that finite‐amplitude disturbances are always necessary to initiate secondary eyewalls, regardless of the initial humidity of the lower troposphere. Experiments with both models, in which the surface wind is held constant in the surface flux formulations, fail to develop secondary eyewalls, demonstrating that in these models the disturbances, once initiated, grow through the wind‐induced surface heat exchange (WISHE) mechanism. Based on this work, we hypothesize that real secondary eyewalls result from a finite‐amplitude WISHE instability, triggered by external forcing, such as interaction of the tropical cyclone with baroclinic eddies, topography, or local perturbations in sea surface temperature. Copyright © 2003 Royal Meteorological Society
Adjustment to heating, potential vorticity and cyclogenesis
Authors: Delden Aarnout Van
Published: December 2003

Solutions of an isentropic coordinate model of the atmosphere, permitting acoustic waves and inertial gravity waves, demonstrate that a vertically symmetric heat source in the troposphere usually induces a vertically asymmetric dipole anomaly in the potential vorticity (PV), with an intense, tall and thin positive (cyclonic) anomaly below a less intense, flat and broad negative (anticyclonic) anomaly. The emergence of this asymmetry is associated with the vertical gradient of the PV, which is an important factor in the local PV budget, even when this gradient is zero initially. The degree of vertical asymmetry of the response to heating depends on the ‘thickness’ (in K) of the heated layer relative to the total heat added. The adjusted balanced state shows little sensitivity to the heating intensity (i.e. the time‐scale within which the heat is added), in spite of the existence of large‐amplitude waves when the heating is applied very abruptly relative to the adiabatic adjustment time‐scale. The surrounding (non‐heated) region shows little permanent change due to the process of adjustment as far as PV substance and mass is concerned, and only functions as a transmitter of acoustic waves and inertial gravity waves. The balanced state is sensitive to variations in the horizontal scale of the heat source. The response to heating within a PV stratified region (for example, in the region of the tropopause) is quite subtle. For example, it is shown that a heat source in the tropopause region induces a predominantly anticyclonic wind anomaly. Copyright © 2003 Royal Meteorological Society
Modelling of error covariances by 4D‐Var data assimilation
Authors: Lorenc Andrew C.
Published: December 2003

The extended Kalman filter is presented as a good approximation to the optimal assimilation of observations into a numerical weather prediction (NWP) model, as long as the evolution of errors stays close to linear. The error probability distributions are approximated by Gaussians, characterized by their mean and covariance. The full nonlinear forecast model is used to propagate the mean, and a linear model (not necessarily tangent to the full model) the covariances. Since it is impossible to determine the covariances in detail, physically based assumptions about their behaviour must be made; for instance, three‐dimensional balance relationships are used. The linear model can be thought of as extending the covariance relationships to the time dimension. Incremental four‐dimensional variational (4D‐Var) is derived as a practical implementation of the extended Kalman filter, optimally using these modelled covariances for a finite time window. It is easy to include a simplified model of forecast errors in the representation. This Kalman filter based paradigm differs from more traditional derivations of 4D‐Var in attempting to estimate the mean, rather than the mode, of the posterior probability density function. The latter is difficult for a NWP system representing scales which exhibit chaotic behaviour over the period of interest.

The covariance modelling assumptions often result in a null space of error modes with little variance. It is argued that this is as important as the variance and correlation structures usually examined, since the implied constraints allow optimal use of observations giving gradient and tendency information.

Difficulties arise in the approach when the NWP system is capable of resolving significant structures (such as convective cells) not always determined by the observations. © Crown copyright, 2003. Royal Meteorological Society
The potential of the ensemble Kalman filter for NWP—a comparison with 4D‐Var
Authors: Lorenc Andrew C.
Published: December 2003

The ensemble Kalman filter (EnKF) is reviewed for its expected assimilation characteristics and ease of implementation, and compared to the currently more popular four‐dimensional variational assimilation (4D‐Var). The EnKF is attractive when building a new medium‐range ensemble numerical weather prediction (NWP) system. However it is less suitable for NWP systems with uncertainty in a wide range of scales; it may not use high‐resolution satellite data as effectively as 4D‐Var. For limited‐area mesoscale NWP systems a hybrid method is attractive. © Crown copyright, 2003. Royal Meteorological Society
The omega equation and potential vorticity
Authors: Hoskins Brian , Pedder Mike , Jones David Wyn
Published: December 2003

Two fundamental perspectives on the dynamics of midlatitude weather systems are provided by potential vorticity (PV) and the omega equation. The aim of this paper is to investigate the link between the two perspectives, which has so far received very little attention in the meteorological literature. It also aims to give a quantitative basis for discussion of quasi‐geostrophic vertical motion in terms of components associated with system movement, maintaining a constant thermal structure, and with the development of that structure. The former links with the isentropic relative‐flow analysis technique. Viewed in a moving frame of reference, the measured development of a system depends on the velocity of that frame of reference. The requirement that the development should be a minimum provides a quantitative method for determining the optimum system velocity. The component of vertical velocity associated with development is shown to satisfy an omega equation with forcing determined from the relative advection of interior PV and boundary temperature. The analysis carries through in the presence of diabatic heating provided the omega equation forcing is based on the interior PV and boundary thermal tendencies, including the heating effect. The analysis is shown to be possible also at the level of the semi‐geostrophic approximation.

The analysis technique is applied to a number of idealized problems that can be considered to be building blocks for midlatitude synoptic‐scale dynamics. They focus on the influences of interior PV, boundary temperature, an interior boundary, baroclinic instability associated with two boundaries, and also diabatic heating. In each case, insights yielded by the new perspective are sought into the dynamical behaviour, especially that related to vertical motion. Copyright © 2003 Royal Meteorological Society
The global distribution of ice‐supersaturated regions as seen by the Microwave Limb Sounder
Authors: Spichtinger Peter , Gierens Klaus , Read William
Published: December 2003

Cloud‐screened microwave limb‐sounder data of relative humidity with respect to ice have been used to produce maps of the global distribution of ice‐supersaturated regions (ISSRs) at pressure levels 147 and 215 hPa. Geographical regions where ISSRs occur most frequently (in a relative sense) are the tropics at both pressure levels, the midlatitude storm belts at 215 hPa (in the respective hemispheric summer and autumn seasons) and Antarctica in southern winter and spring (at both pressure levels). Additionally, temperatures and absolute humidities were compared in supersaturated and subsaturated air masses. Consistent with earlier results based on data from the Measurement of Ozone by Airbus in‐service Aircraft, it is found that ISSRs are generally colder and moister than their subsaturated counterparts. Temperature and humidity contrasts between supersaturated and subsaturated air masses vary considerably, both geographically and between the troposphere and the lowermost stratosphere. Copyright © 2003 Royal Meteorological Society
Ozone signatures of climate patterns over the Euro‐Atlantic sector in the spring
Authors: Orsolini Y. J. , Doblas‐Reyes F. J.
Published: December 2003

The influence of low‐frequency tropospheric dynamics upon column ozone interannual variability is estimated in the spring season over the Euro‐Atlantic sector. This dynamical variability of tropospheric origin is examined in terms of leading climate patterns, derived from an empirical orthogonal function analysis of the National Center for Environmental Prediction 500 mb geopotential height analyses. In order to fingerprint the spatial and temporal ozone signatures of these patterns, the Total Ozone Mapping Spectrometer satellite observations of column ozone during the last two decades are used. The geographical ozone signatures of these climate patterns are extracted by linear regression and their time evolution reconstructed.

Geopotential anomalies associated with four leading patterns of variability (the North Atlantic Oscillation (NAO), the Scandinavian pattern, the east Atlantic pattern and the European blocking pattern) induce column ozone anomalies in the range of 5–15 Dobson Units per standard deviation of the pattern index. The impact of these combined Euro‐Atlantic climate patterns upon the regional ozone trends and interannual variability is also estimated. In order to reconstruct the regional ozone trend and variability, it proved important to incorporate several patterns, in addition to the dominant NAO. A hitherto little‐known lifting of the Arctic tropopause by the polar night jet is also shown to imprint upon the ozone signatures of some patterns. Copyright © 2003 Royal Meteorological Society
Topographically induced waves within the stable boundary layer
Authors: Brown A. R. , Athanassiadou M. , Wood N.
Published: December 2003

Results are presented from numerical simulations of stable boundary‐layer flow over low ridges. Internal gravity waves are seen within the boundary layer when a Froude number based on the wavelength of the ridges and the magnitude of the cross‐ridge velocity component becomes sufficiently small. It is noted that this can always be achieved, even for short‐wavelength ridges, if the ridge axis is aligned so as to be closely parallel to the wind direction. The surface pressure forces are found to be highly sensitive to the presence of gravity waves, and are also affected by the presence of critical levels within the boundary layer. © Crown copyright, 2003. Royal Meteorological Society
On entrainment rates in nocturnal marine stratocumulus
Authors: Stevens Bjorn , Lenschow Donald H. , Faloona Ian , Moeng C.‐H. , Lilly D. K. , Blomquist B. , Vali G. , Bandy A. , Campos T. , Gerber H. , Haimov S. , Morley B. , Thornton D.
Published: December 2003

The first research flight of the second Dynamics and Chemistry of Marine Stratocumulus field study is analysed. This case attracted our interest because it showed a consistently deepening cloud layer despite macroscopic conditions which previous work has suggested should be an indication of cloud thinning or breakup. Detailed analysis of the flight data shows that despite the cloud‐top entrainment instability parameter being well beyond its critical value the cloud did indeed deepen through the night. Our best estimates show little indication of rapid changes in cloud top, while cloud base was found to be lowering at a rate of several metres per hour. This evolution, and independent measurements of trace‐gas budgets, imply an entrainment rate of 0.0039±0.001 m s−1. This is compared to entrainment rates from recently proposed parametrizations (forced by the observed forcing of the cloud layer) which range from 0.002 to 0.008 m s−1. Two of the parametrizations we test reproduce the observed entrainment rates within their stated uncertainties, although subsequent tests show that one of these rules exhibits sensitivities to changes in the environmental conditions which are difficult to justify. Large‐eddy simulation of the observed case was able to reproduce the macroscopic evolution of the layer, but in doing so had some difficulty in maintaining the observed mixing‐line structure at cloud top. A comparison of the observed and simulated turbulent structure show these to be broadly consistent, although there is an indication that the structure of the simulated turbulence differs from the observations near the flow boundaries, particularly at cloud top. Copyright © 2003 Royal Meteorological Society
Coupled chemistry–climate model simulations for the period 1980 to 2020: Ozone depletion and the start of ozone recovery
Authors: Austin John , Butchart Neal
Published: December 2003

Two simulations of a coupled chemistry–climate model are completed for the period 1980 to 2020, covering the recent past during which extensive satellite ozone and temperature data exist, and covering the near future when ozone levels are expected to begin to recover. In the first simulation, Rayleigh friction is used to decelerate the polar night jet. In the second simulation, a parametrized spectral gravity‐wave forcing scheme is included. This has the effect of considerably reducing the model temperature bias in the polar regions and weakening the polar night jet. In the simulations the concentrations of chlorine, bromine and the well‐mixed greenhouse gas concentrations are specified in accordance with past observations and future projected values. The calculated trends in temperature and ozone in the two runs are similar, indicating that model internal variability does not have a significant impact and suggesting that the trends arise largely from changes in external parameters. Typically, after about the year 2000, the trend in the modelled annually averaged ozone changed from a decrease to a small increase. The change was found to be statistically significant in the upper stratosphere and in the lower stratosphere over Antarctica, which are the regions most affected by halogen chemistry. Globally averaged temperature results suggest that the best place to look for future atmospheric change is in the upper stratosphere. Decadally averaged statistics are used to estimate the timing of the start of recovery of total ozone. The simulations indicate no significant further ozone loss from the current atmosphere with minima typically occurring in the years from 2000 to 2005, except in the spring Arctic where ozone values continued to decrease slowly until the end of the integrations. One major problem with the detection of the start of ozone recovery, is that the concentrations of halogens are expected to reduce only slowly from their peak value. Hence, no substantial recovery is simulated before the year 2020. The difficulty in detecting the start of ozone recovery suggests the need to continue the model simulations until the second half of this century which would also help to establish the timing of complete ozone recovery. © Crown copyright, 2003. Royal Meteorological Society
A cloud detection algorithm for high‐spectral‐resolution infrared sounders
Authors: McNally A. P. , Watts P. D.
Published: December 2003

A method for detecting cloud contamination in radiances measured by high‐spectral‐resolution infrared sounders is presented. It seeks to identify clear channels within a measured spectrum, rather than the locations of completely clear spectra. Applied to simulated cloudy spectra, the scheme is able to detect clear channels with residual cloud contamination better than (i.e. less than) 0.2 K in many channels, and is thus considered sufficiently stringent for numerical weather‐prediction applications. The scheme has been applied to spectra measured by the Advanced InfraRed Sounder and, whilst a quantitative validation is more difficult with real data (without true clear radiances), it is found to perform well compared with coincident imagery. Copyright © 2003 Royal Meteorological Society
Summertime low‐ozone episodes at northern high latitudes
Authors: Orsolini Y. J. , Eskes H. , Hansen G. , Hoppe U.‐P. , Kylling A. , Kyrö E. , Notholt J. , Der A R. Van , Gathen P. Von Der
Published: December 2003

A pool of low‐ozone air resides in the Arctic stratosphere in summer. Its formation and maintenance arise from a combination of chemical ozone‐destruction and transport processes. The summertime ozone destruction is induced by gas‐phase chemistry dominated by nitrogen and hydrogen catalytic cycles, which are efficient due to long summertime insolation at high latitudes. It is shown that, during events referred to as low‐ozone episodes (LOEs), column ozone can locally decrease to values comparable with the seasonal minimum. A combination is used of (i) assimilation of satellite ozone observations from the Global Ozone Monitoring Experiment, (ii) chemical trajectory modelling, and (iii) the gathering of new lidar andin situozone observations in the European Arctic in summer 2000. Hence it is shown that such LOEs involve the displacement of the pool of low‐ozone air in the middle stratosphere, which is more dynamic than previously thought and undergoes pronounced meridional excursions, in particular towards northern Europe. The thinner the ozone layer, the more ultraviolet (UV) radiation reaches the ground, where it can impact on human health and ecosystems. Erythemal UV dose enhancements of the order of 10–15% were observed in northern Norway during the LOEs in summer 2000. Copyright © 2003 Royal Meteorological Society
Comment on the connection between stability and entropy production
Authors: Nicolis C.
Published: December 2003

The recently formulated hypothesis by Shimokawa and Ozawa that a nonlinear system is likely to move to a state of maximum entropy production by perturbation is shown to be of limited generality. Copyright © 2003 Royal Meteorological Society
On the impacts of the Indian summer monsoon on ENSO in a coupled GCM
Authors: Wu Renguang , Kirtman Ben P.
Published: December 2003

This study explores the impacts of the Indian summer monsoon (ISM) on the El Niño–Southern Oscillation (ENSO) evolution by utilizing two coupled general‐circulation model simulations. The first simulation uses the Center for Ocean–Land–Atmosphere Studies anomaly‐coupled model and the second simulation employs a new coupling strategy, interactive ensembles, that is designed to increase the signal‐to‐noise ratio of boundary forcing. The effects of monsoon variability related and unrelated to ENSO are separated through composites in terms of both sea surface temperature (SST) over the Niño‐3.4 area (170°W–120°W,5°S–5°N) and Indian summer monsoon rainfall (IMR) anomalies. It is found that ENSO‐related monsoon variability has significant impacts on warm events. In the interactive‐ensemble simulation, a weak (strong) monsoon enhances (weakens) an ongoing warm event. The monsoon impacts are manifested in the surface zonal wind‐stress anomalies in the western central equatorial Pacific. In the anomaly‐coupled simulation, the monsoon–ENSO relationship is difficult to detect. The ongoing cold events are only weakly affected by monsoon variability. Monsoon variability that is unrelated to ENSO also induces noticeable SST anomalies in the equatorial central Pacific in the following winter. In the interactive‐ensemble model, a weak (strong) monsoon induces noticeable warm (cold) SST anomalies.

The long‐term change of the ISM–ENSO relationship is also analysed. Fluctuations of the IMR–Niño‐3.4 SST correlation are larger in the anomaly‐coupled model than in the interactive‐ensemble model. No apparent relation is found between the long‐term change of the correlation and that of the monsoon and ENSO anomalies or standard deviations. In the interactive‐ensemble simulation, the IMR and concurrent El Niño‐3.4 SST standard deviations show in‐phase long‐term changes. In the anomaly‐coupled simulation, the long‐term changes of the IMR and summer Niño‐3.4 SST standard deviations have an out‐of‐phase relation. Copyright © 2003 Royal Meteorological Society
Evaluation of moisture in the Hadley Centre climate model using simulations of HIRS water‐vapour channel radiances
Authors: Allan Richard P. , Ringer M. A. , Slingo A.
Published: December 2003

It is important to establish that climate models can accurately simulate the observed present‐day fluctuations of water vapour. In particular, water‐vapour and cloud‐radiative feedbacks are intrinsically linked to processes governing relative‐humidity distribution and variability. To explore these issues, clear‐sky radiances, sensitive to upper‐tropospheric relative humidity, are simulated within the Hadley Centre atmospheric climate model, version HadAM3, allowing direct comparison with High Resolution Infrared Sounder (HIRS) observations. The model is forced by observed sea surface temperatures and sea‐ice fields over the period 1979–98. Evaluation of the simulated distribution and variability of water vapour is undertaken utilizing the HIRS 6.7 μm brightness temperature (T6.7) and satellite measurements of column‐integrated water vapour and clear‐sky outgoing long‐wave radiation (OLR). Modifications are made to the clear‐sky OLR and T6.7 HadAM3 diagnostics to reduce sampling inconsistencies with the observed products. Simulated T6.7 over subtropical dry zones are higher than T6.7 from observations, particularly in the southern hemisphere, and is symptomatic of an overactive circulation. The observed spatial signature of the T6.7 interannual variability is dominated by El Niño and is captured well by HadAM3. Interannual variability of the tropical ocean mean T6.7 is consistent between HadAM3 and the HIRS observations, suggesting that the small simulated decadal changes in relative humidity are realistic. © Crown copyright, 2003. Royal Meteorological Society
The effect of surface lobes on heat transfer from an ice particle
Authors: Aguirre Varela Guillermo G. , Castellano Nesvit E. , Pereyra Rodolfo G. , Avila Eldo E.
Published: December 2003

The convection heat‐transfer coefficient for circular cylinders, exposed to an air stream perpendicular to their axis, is dependent on the Reynolds number, Re. There is experimental evidence showing that the heat‐transfer coefficient for hail or graupel growing by accretion of supercooled water droplets is greater than that corresponding to an equivalent smooth surface. Work carried out so far indicates that surface roughness could influence this coefficient. This work presents an experimental study of the influence of lobes on the heat‐transfer process to the surroundings from metallic cylinder surfaces. The dependence of the heat‐transfer coefficient on Re was studied for $2000 < Re < 20\ 000$.

Results show that the presence of lobes and lumps on a smooth surface could, in some cases, increase the heat transfer towards the surroundings by ventilation. However, results also show that this is not likely to be the effect responsible for increasing the ventilation coefficient for graupel compared with smooth surfaces. Copyright © 2003 Royal Meteorological Society
Can knowledge of the state of the stratosphere be used to improve statistical forecasts of the troposphere?
Authors: Charlton A. J. , O'Neill A. , Stephenson D. B. , Lahoz W. A. , Baldwin M. P.
Published: December 2003

Recent analysis of the Arctic Oscillation (AO) in the stratosphere and troposphere has suggested that predictability of the state of the tropospheric AO may be obtained from the state of the stratospheric AO. However, much of this research has been of a purely qualitative nature. We present a more thorough statistical analysis of a long AO amplitude dataset which seeks to establish the magnitude of such a link.

A relationship between the AO in the lower stratosphere and on the 1000 hPa surface on a 10–45 day time‐scale is revealed. The relationship accounts for ∼5% of the variance of the 1000 hPa time series at its peak value and is significant at the 5% level. Over a similar time‐scale the 1000 hPa time series accounts for ≤1% of itself and is not significant at the 5% level. Further investigation of the relationship reveals that it is only present during the winter season and in particular during February and March. It is also demonstrated that using stratospheric AO amplitude data as a predictor in a simple statistical model results in a gain of skill of ∼5% over a troposphere‐only statistical model. This gain in skill is not repeated if an unrelated time series is included as a predictor in the model. Copyright © 2003 Royal Meteorological Society
The effect of baroclinicity on the equilibrium depth of neutral and stable planetary boundary layers
Authors: Zilitinkevich Sergej S. , Esau Igor N.
Published: December 2003

Earlier studies of the depths of the geophysical planetary boundary layers (PBLs) basically focused on the effects of the earth's rotation and density stratification. One more inherent feature of geophysical flows, namely their baroclinicity, has not been considered in that context. The present paper makes up for this deficiency. Diagnostic equations for the depths of the equilibrium, baroclinic, neutral or stable PBLs are derived and verified against data from large‐eddy simulations (LES). These latter represents the most convenient empirical‐validation tool, which allows considering separately different types of PBL: barotropic and baroclinic; truly neutral and conventionally neutral; nocturnal stable and long‐lived stable. The LES are performed using a new code specifically designed for modelling the neutral and stable PBL. Results from the comparison show an excellent correspondence between the proposed equations and LES data. Copyright © 2003 Royal Meteorological Society
Ling's Death: An Ethnography of a Chinese Woman's Suicide
Authors: Pearson Veronica , Meng Liu PhD
Published: December 2003

Over the past decade, great concern has been expressed about the high suicide rates in China, especially among women and young women in particular. However, most of the information that has been presented has considered macro‐level data and speculated on why women are so vulnerable to self‐harm. This article presents the detailed story of one village woman who killed herself and suggests that motives and behavior are more complex than the cultural script and statistics suggest. Although depression is said to be commonly present in people who kill themselves in Western countries, this may not be the case in China.
Attempted Suicide among Young Rural Women in the People's Republic of China: Possibilities for Prevention
Authors: Pearson Veronica , Phillips Michael R. , He Fengsheng , Ji Huiyu
Published: December 2003

This article reports on a sample of 147 women under age 35 living in rural areas in China who had attempted suicide and were treated in the emergency room of hospitals in four different locations. The interview instrument took 2 to 3 hours to complete and included audiotaped in‐depth interviews with the patient and family members (separately); detailed evaluation of the circumstances surrounding the attempt, life events, and the family environment; and a formal psychiatric evaluation by an attending‐level psychiatrist. Overwhelmingly, the method used by the attempters was poisoning with highly lethal pesticides and organic fertilizers. The women's suicidal behavior was characterized by high levels of impulsivity; little effort to seclude themselves before and after ingesting poison; and low rates of mental illness, including depression. Detailed suggestions are made about ways to implement suicide prevention strategies within the particular social and economic context of China.
Studying Suicide with Psychological Autopsy: Social and Cultural Feasibilities of the Methodology in China
Authors: Zhang Jie , Wieczorek William F. , Jiang Chao , Zhou Li , Jia Shuhua , Sun Yueji , Jin Shenghua , Conwell Yeates
Published: December 2003

As China opens its door to the world, suicide research is making rapid progress using methods and instruments developed in the West. This is a feasibility study of the psychological autopsy methodology applied in China, with its emphasis on the social and cultural environments. With samples of 66 completed suicides and 66 community normal living controls, the authors found that it is feasible to interview at least two informants for each suicide case and each control, between 2 and 6 months after the suicide. With the Chinese‐cultivated contacting method of recruiting cases, the refusal rate is nearly zero. The Western‐developed methodology per se proved to be valid in the Chinese culture. Ethical considerations in the context of Chinese culture are as important as in the West. Psychological autopsy technique is shown to be an equally applicable method for the study of completed suicides in Chinese culture as it is in the West. Future epidemiological research on Chinese suicide should use the psychological autopsy method to collect data from larger samples in order to increase our understanding of the risk factors for Chinese suicides.
Why People Engage in Parasuicide: A Cross‐Cultural Study of Intentions
Authors: Hjelmeland Heidi , Hawton Keith , Nordvik Hilmar , Bille‐Brahe Unni , Leo Diego De , Fekete Sandor , Grad Onja , Haring Christian , Kerkhof Ad J.F.M. , Lönnqvist Jouko , Michel Konrad , Renberg Ellinor Salander , Schmidtke Armin , Van Heeringen Kees , Wasserman Danuta
Published: December 2003

Information obtained at interview from 1,646 parasuicide patients in 14 regions in 13 European countries participating in the WHO/EURO Multicentre Study on Suicidal Behaviour was used to study self‐reported intentions involved in parasuicide. Comparisons were made across cultures, genders, and age groups. Although some statistically significant differences were found, the effect sizes were very small. The main finding from this study is thus that parasuicide patients in different countries tend to indicate that similar types of intentions are involved in their acts of parasuicide, and that the intentions do not vary greatly with gender or age. The hypothesis that rates of suicide and parasuicide vary between regions with the frequency with which suicidal intention is indicated by the patients was also tested, but was supported only for women and in relation to national suicide rates. The findings from this study are likely to be generalizable to other settings and have implications for clinical practice.
Mental Health Literacy of those with Major Depression and Suicidal Ideation: An Impediment to Help Seeking
Authors: Goldney Robert D. , Fisher Laura J. , Wilson David H. , Cheok Frida
Published: December 2003

Mental health literacy is the knowledge and beliefs about mental disorders that aid their recognition, management, or prevention, and is an important determinant of help seeking. This has relevance in suicide prevention, particularly for those with major depression, the clinical condition most frequently associated with suicidal behavior. In this study of a random and representative community sample, a vignette depicting classical features of major depression was presented to subjects along with questions related to mental health literacy. The responses of those with major depression, as delineated by the Primary Care Evaluation of Mental Disorders instrument, both with and without suicidal ideation, were compared to those of a third group of respondents. The results demonstrated that despite increased professional contact by those with major depression and suicidal ideation, there were few differences among the three groups on either open‐ended or direct questions related to mental health literacy. This indicates that increased professional contact in itself was not related to increased mental health literacy, and suggests that more specific psychoeducational programs are required.
Religiosity, Attributional Style, and Social Support as Psychosocial Buffers for African American and White Adolescents' Perceived Risk for Suicide
Authors: Greening Leilani , Stoppelbein Laura
Published: December 2003

Psychosocial buffers were evaluated for their relative contributions to adolescents' perceived risk for suicide., A community sample of African American and White adolescents (N= 1,098) rated the likelihood that they would die by suicide , and completed standardized measures of depression, hopelessness, intrinsic and extrinsic religiosity, orthodoxy, social support, and causal attributional style. Orthodoxy—commitment to core beliefs—emerged as the single strongest correlate after controlling for the effects of other buffers. The effect of depression on perceived suicide risk was moderated by the adolescent's degree of orthodoxy. Commitment to core, life‐saving beliefs may help explain the religion‐suicide link for adolescents.
The Association between Homelessness and Suicidal Ideation and Behaviors: Results of a Cross‐sectional Survey
Authors: Eynan Rahel , Langley John , Tolomiczenko George , Rhodes Anne E. , Links Paul , Wasylenki Donald , Goering Paula
Published: December 2003

This study was carried out with three goals: (1) to determine the prevalence of suicidal ideation and suicide attempts among the homeless; (2) to determine what aspects of homelessness predict suicidality; and (3) to determine which aspects remain predictive after controlling for key covariates, such as mental illness. A sample of 330 homeless adults were interviewed. Sixty‐one percent of the study sample reported suicidal ideation and 34% had attempted suicide. Fifty‐six percent of the men and 78% of the women reported prior suicidal ideation, while 28 percent of the men and 57% of the women had attempted suicide. Childhood homelessness of at least 1 week without family members and periods of homelessness longer than 6 months were found to be associated with suicidal ideation. Psychiatric diagnoses were also associated with suicidality in this sample.
Does Writing About Suicidal Thoughts and Feelings Reduce Them?
Authors: Kovac Stacey H. , Range Lillian M.
Published: December 2003

To assess whether writing with cognitive change or exposure instructions reduces depression or suicidality, 121 undergraduates screened for suicidality wrote for 20 minutes on 4 days over 2 weeks. They were randomly assigned to reinterpret or to write and rewrite traumatic events/emotions, or to write about innocuous topics. The three groups (N= 98) who completed pre‐, post‐, and 6‐week follow‐up were not different on suicidality or depression. All subjects reported fewer automatic negative thoughts over the 2 weeks; they also reported higher self‐regard but more health center visits at follow‐up. Suicidal thoughts may be more resistant than physical health to writing interventions.