bluuebunny/crossref_metadata_2025 huggingface dataset:
Phytosociology of subalpine coniferous forests in Korea I. Syntaxonomical interpretation
Authors: Song Jong Suk
Published: April 2006

In phytosociological studies of Korean subalpine confierous forests of the class Vaccinio‐Piceetea Br.‐Bl. 1939, new two alliances are described. They are Abieti nephrolepidis‐Piceion jezoensis of the Korean Peninsula and Abietion koreanae on Mt. Halla, Cheju Island. The former contains three associations: (1) Taxo‐Pinetum pumilae song et Nakanishi 1985, (2) Thujo‐Abietetum nephrolepidis assoc. nov. and (3) Abieti koreanae‐Piceetum jezoensis assoc. nov. The latter contains two associations: (1) Saso‐Abietelum koreanae Song et Nakanishi 1985 with two subassociations and (2) Betulo saitoanae‐Abietetum koreanae Song et Nakanishi 1985 em. The ecological and phytogeographical relationships of the vegetation units are described and discussed.
Revegetation process on a subalpine mudflow
Authors: Kimura Wakio
Published: April 2006

The process of revegetation on a subalpine mudflow was analyzed on the basis of the vegetation‐soil relationship of the revegetated stands, and of the age structure and height growth process of the trees. Based on evidence derived from five independent sources, it was concluded that this mudflow was caused by a typhoon in 1959. The revegetated stands were classified into three vegetation types. An Alnus maximowiczii stand was established where the surface soil was unstable; a Betula ermanii stand was established where the degree of disturbance by the mudflow was small; an Alnus‐Betula stand was the intermediate type and occupied most of the area on the mudflow. Alnus had colonized concentrically 4–6 yr after the mudflow, and Betula and conifers had followed 1–2 yr later. As revegetation proceeded, the trees became differentiated into two populations, a canopy population and a suppressed one. The former was dominated mainly by Alnus and the latter by Betula and conifers. This differentiation was caused by the faster growth of Alnus during the initial years of colonization. Some Betula trees have recently grown faster than Alnus, suggesting future replacement in dominance. Conifers have grown slowly even during recent years; the highly oligotrophic condition of the soil appears to have been responsible for this delayed growth.
Inhibition of photosynthesis of Populus euramericana and Helianthus annuus by SO2, NO2 and O3
Authors: Furukawa Akio
Published: April 2006

Populus euramericana cv. I‐214 and Helianthus annuus L. cv. Russian Mammoth were exposed to various concentrations of O3 SO2 or NO2 for 2 h in a cylindrical assimilation chamber. The threshold concentrations of air pollutants for inhibition of net photosynthesis differed between the two species and also between the pollutants tested. Furthermore, the lethal concentrations where the net photosynthetic rates were completely inhibited, also differed between species and between pollutants. For SO2 and NO2, P. euramericana was more tolerant photosynthetically than H. annuus when related to the concentration of pollutants used during the experiment. However, when related to the cumulative uptake rate of each pollutant, the photosynthetic tolerance of the two species was similar. In contrast to the effects of SO2 or NO2, the influence of O3 on net photosynthesis was quite different. The relative rates of net photosynthesis in both species showed the same linear relationship with O3 concentration. However, the relationship between the relative rate of net photosynthesis and the cumulative uptake rate of O3 differed between the two species, although it was linear in both cases.
Climate and vegetation in China V. Effect of climatic factors on the upper limit of distribution of evergreen broadleaf forest
Authors: Fang Jing‐yun , Yoda Kyoji
Published: April 2006

In order to clarify correlations between the upper limit of distribution of evergreen broadleaf forest and climatic factors, 62 stands distributed at the upper limit of the forest were collected from various parts of China, and their thermal and precipitation factors were estimated. Among six thermal climatic indices, i.e., warmth index (WI), coldness index (CI) and annual mean (AMT), January mean (JMT), mean minimum (MMT) and minimum (MT) temperatures, the CI at the stands showed the smallest range of variance, and it was therefore considered to be the most significant for interpreting the upward distribution of the forest. However, the distribution of the forest in mountain areas in southwestern China could not be explained by lower temperatures in winter such as CI but by a cumulative temperature such as WI. The continentality and precipitation factors were also important for delimiting the distribution of the forest. In addition, the relation between the distribution of the forest and the MMT was noted, and it was concluded that the MMT was an effective thermal index for explaining the upper limit of distribution of evergreen broadleaf forest in China.
Multiple effects of precipitation on Salix lasiolepis and populations of the stem‐galling sawfly, Euura lasiolepis
Authors: Price Peter W. , Clancy Karen M.
Published: April 2006

Relatively low winter precipitation (e.g., 18–28 cm from October to May compared to 45 to 65 cm) caused reduced growth of the arroyo willow, Salix lasiolepis, with number of shoots per stem initiated and shoot length reduced. Resources were reduced for the stem‐galling sawfly, Euura lasiolepis, which declined in numbers after the relatively dry winter of 1980–81. Sawfly phenology was advanced relative to willow phenology in the 1981 generation, causing an additional reduction in resource availability. These direct effects of precipitation on the sawfly were increased by indirect effects on survivorship of the 1981 generation. Egg death in galls increased on water‐stressed willow plants, forming the major mortality in the generation. This resulted in very low survival in the generation and an even lower population in the 1982 generation, even though resources recovered after high precipitation during the 1981–82 winter (46.7 cm). An experiment using high, medium, and low water treatments on potted willow plants demonstrated that the effects on willows and sawflies could be reproduced using only water as a variable.
The feeding ecology of the pit‐making ant lion larva, Myrmeleon bore: Feeding rate and species composition of prey in a habitat
Authors: Matsura Toshiaki
Published: April 2006

The prey species composition and feeding rate of the pit‐making ant lion larva, Myrmeleon bore Tjeder, which inhabits open sandy areas, were examined. Not less than 30 prey species, most of which were ants, were collected during a research period of 1.5 years. First instar larvae most often (81.1%) captured ants. Although 3rd instar larvae captured larger‐sized prey than individuals of any other instar, they also captured small prey. The feeding rate of 3rd instar larvae was estimated by using the frequency of observed predation (FOP; (no. of ant lions handling a prey)/(total no. of pits observed)), the prey‐handling time and the rhythm of daily foraging activity. FOP of M. bore larvae was constant on the whole from spring to autumn. It was estimated that each captured 1.25 prey per day on average during this period. This estimate, however, was the feeding rate for days on which there was no rain. Assuming that the larvae cannot capture prey due to pit destruction when there is more than 10 mm of rainfall per day, the figure was reduced to 1.03 prey/day. The estimated feeding rate was evaluated with reference to larval foraging behavior.
Distribution of carbon, nitrogen and phosphorus in a moss community‐soil system developed on a cold desert in Antarctica
Authors: Ino Yoshio , Nakatsubo Takayuki
Published: April 2006

The distributions of carbon, nitrogen and phosphorus in a moss community‐soil system developed on a naked region in Rundvågskollane (69050'S, 39009'E), East Antarctica, were investigated in order to analyze the flow of matter in an Antarctic terrestrial ecosystem.

The moss community was formed from many moss blocks of different sizes and was composed of Bryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb., Ceratodon purpureus (Hedw.) Brid. and Grimmia lawiana J. H. Willis. The surface of the community was covered with cyanobacteria.

It was estimated that nitrogen fixed by cyanobacteria flowed from these organisms to the moss and that little nitrogen was transported within the moss body.

A large amount of phosphorus existed in the soil. The moss community had a high phosphorus content although the amount itself was relatively little due to the small phytomass.

It seems that absorption of phosphorus from soil is difficult for moss, because of the paucity of water necessary for the movement of phosphorus and the suppressed growth of moss due to the arid conditions.
‘Safe sites’ for the seed germination of Rhus javanica: A characterization by responses to temperature and light
Authors: Washitani Izumi , Takenaka Akio
Published: April 2006

Germination responses of Rhus javanica L. seeds to temperature and light were investigated with special reference to their gap‐detecting mechanisms in germination, i.e., responses to elevated and/or fluctuating temperatures and sensitivity to leaf‐canopy transmitted light. The seeds, which have water‐impermeable coats to prevent imbibition, were shown to become permeable and germinable after exposure to higher temperatures of 48–74°C for a brief period depending on the temperature. Once the coat impermeability had been removed by such heat treatment, the seeds became readily germinable over a wide range of temperature and light conditions. The lower and higher temperature limits for germination were around 8° and 36°C, respectively, with an optimal temperature of around 25°C. Simple linear relationships were observed between the temperature and germination rates, i.e., the reciprocals of the time taken by the seed subpopulations to show 10–70% germination in the sub‐optimal temperature range, where the required ‘thermal time’ for germination was 2300–3600 Kh. The presence or absence of light or a simulated ‘canopy light’ had little effect on the germination of this species. It was concluded that the seeds of R. javanica are furnished with a gap‐detecting mechanism in the form of a heat requirement for the breakage of water‐impermeable seed dormancy, which may be fulfilled by either daytime elevation of the surface temperature of exposed soil, or more effectively by fire.
Great earthquakes of variable magnitude at the Cascadia subduction zone
Authors: Nelson Alan R. , Kelsey Harvey M. , Witter Robert C.
Published: April 2006

Comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate-boundary ruptures of varying length, implying great earthquakes of variable magnitude at the Cascadia subduction zone. Inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis, and relative amounts of coseismic subsidence and heights of tsunamis. Written records of a tsunami in Japan provide the most conclusive evidence for rupture of much of the plate boundary during the earthquake of 26 January 1700. Cascadia stratigraphic evidence dating from about 1600 cal yr B.P., similar to that for the 1700 earthquake, implies a similarly long rupture with substantial subsidence and a high tsunami. Correlations are consistent with other long ruptures about 1350 cal yr B.P., 2500 cal yr B.P., 3400 cal yr B.P., 3800 cal yr B.P., 4400 cal yr B.P., and 4900 cal yr B.P. A rupture about 700–1100 cal yr B.P. was limited to the northern and central parts of the subduction zone, and a northern rupture about 2900 cal yr B.P. may have been similarly limited. Times of probable short ruptures in southern Cascadia include about 1100 cal yr B.P., 1700 cal yr B.P., 3200 cal yr B.P., 4200 cal yr B.P., 4600 cal yr B.P., and 4700 cal yr B.P. Rupture patterns suggest that the plate boundary in northern Cascadia usually breaks in long ruptures during the greatest earthquakes. Ruptures in southernmost Cascadia vary in length and recurrence intervals more than ruptures in northern Cascadia.
Biogeochemical fluxes through mesozooplankton
Authors: Buitenhuis Erik , Le Quéré Corinne , Aumont Olivier , Beaugrand Grégory , Bunker Adrian , Hirst Andrew , Ikeda Tsutomu , O'Brien Todd , Piontkovski Sergey , Straile Dietmar
Published: April 2006

Mesozooplankton are significant consumers of phytoplankton, and have a significant impact on the oceanic biogeochemical cycles of carbon and other elements. Their contribution to vertical particle flux is much larger than that of microzooplankton, yet most global biogeochemical models have lumped these two plankton functional types together. In this paper we bring together several newly available data syntheses on observed mesozooplankton concentration and the biogeochemical fluxes they mediate, and perform data synthesis on flux rates for which no synthesis was available. We update the equations of a global biogeochemical model with an explicit representation of mesozooplankton (PISCES). We use the rate measurements to constrain the parameters of mesozooplankton, and evaluate the model results with our independent synthesis of mesozooplankton concentration measurements. We also perform a sensitivity study to analyze the impact of uncertainty in the flux rates. The standard model run was parameterized on the basis of the data synthesis of flux rates. The results of mesozooplankton concentration in the standard run are slightly lower than the independent databases of observed mesozooplankton concentrations, but not significantly. This shows that structuring and parameterizing biogeochemical models on the basis of observations without tuning is a strategy that works. The sensitivity study showed that by using a maximum grazing rate of mesozooplankton that is only 30% higher than the poorly constrained fit to the observations, the model mesozooplankton concentration gets closer to the observations, but mesozooplankton grazing becomes higher than what is currently accounted for. This is an indication that food selection by mesozooplankton is not sufficiently quantified at present. Despite the amount of effort that is represented by the data syntheses of all relevant processes, the good results that were obtained for mesozooplankton indicate that this effort needs to be applied to all components of marine biogeochemistry. The development of ecosystem models that better represent key plankton groups and that are more closely based on observations should lead to better understanding and quantification of the feedbacks between marine ecosystems and climate.
Aeolian input of bioavailable iron to the ocean
Authors: Fan Song‐Miao , Moxim Walter J. , Levy Hiram
Published: April 2006

Atmospheric deposition of mineral dust supplies much of the essential nutrient iron to the ocean. Presumably only the readily soluble fraction is available for biological uptake. Previous ocean models assumed this fraction was constant. Here the variable solubility of Fe in aerosols and precipitation is parameterized with a two‐step mechanism, the development of a sulfate coating followed by the dissolution of iron (hydr)oxide on the dust aerosols. The predicted soluble Fe fraction increases with transport time from the source region and with the corresponding decrease in dust concentration. The soluble fraction is ∼1 percent near sources, but often 10–40 percent farther away producing a significant increase in soluble Fe deposition in remote ocean regions. Our results may require more rapid biological and physicochemical scavenging of Fe than used in current ocean models. We further suggest that increasing SO2 emission alone could have caused significant Fe fertilization in the modern northern hemisphere oceans.
Global estimates of equatorial inertia‐gravity wave activity in the stratosphere inferred from ERA40 reanalysis
Authors: Le Sommer J. , Teitelbaum H. , Zeitlin V.
Published: April 2006

A new methodology is applied to ERA40 reanalysis in order to quantify large‐scale inertia‐gravity wave activity in the equatorial lower stratosphere. Both eastward and westward propagating waves are identified in the data set and a good agreement is found with previously published in situ observations. Global estimates of vertical fluxes of zonal momentum associated with such waves are obtained. Typical amplitudes of order 10−2 m2. s−2 suggest that the forcing of the Quasi‐Biennial Oscillation by large‐scale inertia‐gravity waves is tantamount to that by Kelvin waves. This method can be used to document the space‐time variability of the wave‐activity in order to improve the wave‐drag parameterizations in climate models.
High correlations between Asian dust events and biological productivity in the western North Pacific
Authors: Yuan Wei , Zhang Jing
Published: April 2006

The relationship between dust events at 11 meteorological stations in China and sediment‐trap fluxes at KNOT (the Kyodo North Pacific Ocean Time‐series station) was investigated during the period December 1997 to April 2000. Al flux, as a good proxy of continental dust, has significant correlations (0.66–0.78) with dust events at a water depth of 924 m. It suggests that the Badain Juran Desert region is a primary source of eolian dust to the western North Pacific. High correlations appeared between the dust events and opal flux, and PD (pennate diatoms) also. This suggests that dust events stimulate biological productivity, providing nutrients via processes such as particle floating, adsorption and co‐precipitation. In addition, evident correlation existed between opal flux at 924 m and GHA (geopotential height anomalies) at 850 hPa level with about a 10‐day time lag. Therefore, it suggests atmospheric cyclone activities might also contribute to ocean productivity.
Zonal mean atmospheric distribution of sulphur hexafluoride (SF6)
Authors: Burgess A. B. , Grainger R. G. , Dudhia A.
Published: April 2006

MIPAS is a polar orbiting high resolution mid‐infrared limb emission sounder with a nominal vertical resolution of 3 km. Building on previous work, we determine global (90°N–90°S, 5° resolution) zonal mean distributions for sulphur hexafluoride from measurements between 6 and 36 km. The time evolution of the global structure is useful for age of air determination and the validation of dynamics in atmospheric models. By comparing solstice and equinox months from 2002 through to 2004, we observe differences which shift with seasonal changes in atmospheric circulation. In addition, a clear systematic increase in the SF6 loading with time is observed globally (0.30 ± 0.025 pptv yr−1). This is compared against independent surface measurements.
Cassini observations of planetary‐period magnetic field oscillations in Saturn's magnetosphere: Doppler shifts and phase motion
Authors: Cowley S. W. H. , Wright D. M. , Bunce E. J. , Carter A. C. , Dougherty M. K. , Giampieri G. , Nichols J. D. , Robinson T. R.
Published: April 2006

Cassini magnetic field observations show that few‐nT oscillations near the planetary rotation period, first observed in Pioneer‐11 and Voyager‐1 and ‐2 fly‐by data, are essentially ubiquitous in Saturn's magnetosphere, though their character differs between the quasi‐dipolar ring current region and the dawn tail. Examination of data from the ring‐current region shows, however, that the observed oscillation period is not fixed at the planetary period, but has smaller values on the inbound pass of the spacecraft, increasing to larger values at and beyond periapsis. These variations are shown to be consistent with the Doppler shifts due to spacecraft motion expected in a model in which the wave phase fronts rotate with the planet, and radiate outward at a speed comparable with the equatorial Alfvén speed.
Quantitative analysis of SCIAMACHY carbon monoxide total column measurements
Authors: de Laat A. T. J. , Gloudemans A. M. S. , Schrijver H. , van den Broek M. M. P. , Meirink J. F. , Aben I. , Krol M.
Published: April 2006

This paper presents a first quantitative and systematic analysis of one year of SCIAMACHY Carbon Monoxide (CO) total column retrievals from the IMLM algorithm (v6.3) using a chemistry‐transport model simulation. The global distribution of modeled and measured CO show similar spatial patterns: a north‐south gradient, low CO over mountains, and high CO over emission regions. CO column errors due to instrument noise are closely related to surface albedo and are less than 6% for monthly means at high surface albedo locations, improving to ∼1% for ideal circumstances: cloud‐free pixels, high surface albedo, and spatial averaging (3° × 2°). Quantitative comparison shows that measured and modeled seasonality agree very well at several locations with different types of seasonal cycles. Differences between SCIAMACHY CO and model results are less than 13% except for regions with large instrument‐noise errors. Differences larger than the 2σ instrument‐noise error (95% confidence interval) occur in some regions with small noise errors, for example southern Africa. In this case the SCIAMACHY CO variations are different from the model biomass‐burning emission seasonal cycle and more in agreement with observed fire count seasonality. The comparison with model results indicates that despite unforeseen time‐dependent instrument‐calibration complications, SCIAMACHY CO total column retrievals are of sufficient quality to provide useful new information on the global distribution and variation of CO.
Joint observations by Cluster satellites of bursty bulk flows in the magnetotail
Authors: Cao J. B. , Ma Y. D , Parks G. , Reme H. , Dandouras I. , Nakamura R. , Zhang T. L. , Zong Q. , Lucek E. , Carr C. M. , Liu Z. X. , Zhou G. C.
Published: April 2006

Using the observations of three satellites of Cluster (C1, C3, and C4) during the periods July to October 2001 and July to October 2002, we study 209 active time bursty bulk flows (BBFs), the difference between single satellite observations and multisatellite observations, and the difference among three selection criteria (two about BBFs and one about rapid convection event). Single satellite observations show that the average duration of BBFs selected by the criterion of Angelopoulos et al. is 604 s, while multisatellite observations show that the average duration of BBFs is 1105 s. Single satellite sometimes misses the BBFs. The missing ratio of single satellite is 22.4% for the criterion of Angelopoulos et al. and 44.9 % for the criterion of Raj et al. Therefore the single satellite observations cannot tell the true number of BBFs. The multisatellite observations are more important for the criterion of Raj et al. The single satellite observations also show that 22% of substorms are not accompanied by BBFs, while multisatellite observations show that only 4.5% of substorms are not accompanied by BBFs. Thus it seems possible that all substorms are accompanied by BBFs. The occurrence frequency of RCEs in the central plasma sheet obtained by multisatellites is 12.2%. The occurrence frequency of BBFs in the central plasma sheet is 9.5% for single satellite observations and 19.4% for multisatellite observations. So BBFs may contribute more to the transport of magnetic flux, mass, and energy than what was estimated by previous studies based on single satellite observations.
Analysis of electron impact ionization properties of methane
Authors: Liu Xianming , Shemansky Donald E.
Published: April 2006

Published experimental photon and electron impact ionization cross sections of CH4 have been reviewed and analyzed. Absolute partial ionization oscillator strengths (fij) for CH4+, CH3+, CH2+, CH+, H+, and H2+ have been obtained. Electron impact ionization cross sections are recommended based on agreement between the oscillator strength values derived from photoionization and electron impact measurements. Analytic functions for cross sections of CH4+, CH3+, CH2+, CH+, C+, H2+, and H+ produced by electron impact ionization of CH4 are established. The derived excitation cross‐section functions are accurate from threshold to impact energies limited by relativistic effects (i.e., E < 0.2 MeV). The cross sections examined here are important for modeling Titan ionospheric chemistry.
Postmidnight convection dynamics during substorm expansion phase
Authors: Liang Jun , Sofko G. J. , Frey H. U.
Published: April 2006

A study of the dynamics of ionospheric plasma convection in the postmidnight sector during the substorm expansion phase (EP) is presented. We have found that after the substorm onset, a postmidnight anticlockwise convection vortex (PoACV) usually emerges at latitudes higher than the auroral brightening region, and an east‐to‐west flow reversal wrapping around the intensified auroras extends into the postmidnight sector. The substorm current system inferred from the relative positions of the PoACV and the auroral brightening region is in general northeast‐southwest aligned, implying a mixture of a meridional current system (MCS) and a zonal system associated with the substorm current wedge (SCW). The time delay between the formation of the PoACV and the onset depends upon the relative azimuthal location of the PoACV and the auroral brightening region. The observed postmidnight convection pattern, namely, a PoACV at higher latitudes, and an east‐to‐west flow reversal region at lower latitudes, can be explained by a combination of the nightside reconnection and the “field line slippage” process associated with dipolarization. Finally, we suggest that strong negative IMF By is the most unfavorable condition for the evolution of the PoACV.
Observations of extremely low tropopause temperature over the Indian tropical region during monsoon and postmonsoon months: Possible implications
Authors: Jain A. R. , Das Siddarth Shankar , Mandal Tuhin K. , Mitra A. P.
Published: April 2006

The present study examines the possible role of the “freeze and dry effect,” which is generally believed to occur when the tropopause temperature is lower than 191 K. So far, there is observational evidence to support the role of the “freeze‐dry mechanism” over the western Pacific region, in particular, over Indonesia. The paper presents observations from four intensive radiosonde/GPS sonde campaigns during summer monsoon and postmonsoon seasons from a number of stations in the tropical Indian region. Observations provide clear evidence of the existence of tropopause temperature lower than 191 K. Analysis suggests that cold tropopause occurs over a wide area of 5° × 5° in latitude and longitude and more often around local midnight hours. Cold tropopause temperature appears to occur more often over the ocean as compared to the coastal stations. The observations at the coastal stations show that on the days of low temperature, the tropopause is cooler by ∼8 K than the climatological temperature for the Indian equatorial region and ∼3.5 K from the mean of all observations. It is noted that on the days of observed cold tropopause, the lapse rate just below the tropopause is closer to the dry adiabatic lapse rate. This indicates a rapid cooling in a narrow height range. The present observations thus provide evidence that the freeze‐dry mechanism could be operating over a wide area, which includes the Indian tropical region. The possible role of atmospheric convection and also of atmospheric waves in producing low tropopause temperatures is examined and discussed.
Absolute accuracy of water vapor measurements from six operational radiosonde types launched during AWEX‐G and implications for AIRS validation
Authors: Miloshevich Larry M. , Vömel Holger , Whiteman David N. , Lesht Barry M. , Schmidlin F. J. , Russo Felicita
Published: April 2006

A detailed assessment of radiosonde water vapor measurement accuracy throughout the tropospheric column is needed for assessing the impact of observational error on applications that use the radiosonde data as input, such as forecast modeling, radiative transfer calculations, remote sensor retrieval validation, climate trend studies, and development of climatologies and cloud and radiation parameterizations. Six operational radiosonde types were flown together in various combinations with a reference‐quality hygrometer during the Atmospheric Infrared Sounder (AIRS) Water Vapor Experiment‐Ground (AWEX‐G), while simultaneous measurements were acquired from Raman lidar and microwave radiometers. This study determines the mean accuracy and variability of the radiosonde water vapor measurements relative to simultaneous measurements from the University of Colorado (CU) Cryogenic Frostpoint Hygrometer (CFH), a reference‐quality standard of known absolute accuracy. The accuracy and performance characteristics of the following radiosonde types are evaluated: Vaisala RS80‐H, RS90, and RS92; Sippican Mark IIa; Modem GL98; and the Meteolabor Snow White hygrometer. A validated correction for sensor time lag error is found to improve the accuracy and reduce the variability of upper tropospheric water vapor measurements from the Vaisala radiosondes. The AWEX data set is also used to derive and validate a new empirical correction that improves the mean calibration accuracy of Vaisala measurements by an amount that depends on the temperature, relative humidity, and sensor type. Fully corrected Vaisala radiosonde measurements are found to be suitably accurate for AIRS validation throughout the troposphere, whereas the other radiosonde types are suitably accurate under only a subset of tropospheric conditions. Although this study focuses on the accuracy of nighttime radiosonde measurements, comparison of Vaisala RS90 measurements to water vapor retrievals from a microwave radiometer reveals a 6–8% dry bias in daytime RS90 measurements that is caused by solar heating of the sensor. An AWEX‐like data set of daytime measurements is highly desirable to complete the accuracy assessment, ideally from a tropical location where the full range of tropospheric temperatures can be sampled.
Ship‐based measurements for infrared sensor validation during Aerosol and Ocean Science Expedition 2004
Authors: Nalli Nicholas R. , Clemente‐Colón Pablo , Minnett Peter J. , Szczodrak Malgorzata , Morris Vernon , Joseph Everette , Goldberg Mitchell D. , Barnet Christopher D. , Wolf Walter W. , Jessup Andy , Branch Ruth , Knuteson Robert O. , Feltz Wayne F.
Published: April 2006

This paper describes a unique validation data set acquired from a marine intensive observing period (IOP) conducted on board the NOAA Ship Ronald H. Brown (RHB) during the 2004 Aerosol and Ocean Science Expedition (AEROSE) in the tropical North Atlantic Ocean from 29 February to 26 March 2004. The radiometric and in situ data complement includes marine observations of the Saharan air layer (SAL), including two significant Saharan dust outbreaks over the Atlantic Ocean. Because the impact of tropospheric dust aerosols on satellite infrared (IR) radiometric observations has not yet been fully characterized, the AEROSE data are particularly valuable for IR sensor validation. Shipboard radiometric data germane to satellite validation include observations from a Marine Atmospheric Emitted Radiance Interferometer (M‐AERI), a Calibrated Infrared In situ Measurement System (CIRIMS), and Microtops handheld sunphotometers. Among other things, these data provide, for the first time, coincident IR spectra of the dry, dusty SAL from both the uplooking M‐AERI and the downlooking Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite. In situ data collected throughout the cruise include Vaisala RS80/90 radiosondes, launched ≃3‐hourly to include Aqua overpass times. The Aqua matchup profiles provide data for validation of AIRS in the presence of high dust loading, along with temperature and water vapor profile retrievals of the SAL. The frequency of sonde launches also enables validation of coincident uplooking M‐AERI boundary layer profile retrievals. Preliminary analyses of the AEROSE data are presented here. Focused AEROSE validation studies are the subjects of separate papers.
Contributions of fossil fuel, biomass‐burning, and biogenic emissions to carbonaceous aerosols in Zurich as traced by 14C
Authors: Szidat Sönke , Jenk Theo M. , Synal Hans‐Arno , Kalberer Markus , Wacker Lukas , Hajdas Irka , Kasper‐Giebl Anne , Baltensperger Urs
Published: April 2006

Many open questions exist about the importance of different sources of carbonaceous aerosol, which is a substantial contributor to the global aerosol budget and, therefore, to climate change and human mortality. In this work, 14C was determined in elemental carbon (EC) and different organic carbon (OC) fractions from ambient urban aerosols with aerodynamic diameter <10 μm collected in Zurich (Switzerland). This enabled a more detailed source attribution of the carbonaceous aerosol mass than is possible with other currently available methods. The three major sources, fossil fuel, wood combustion (both anthropogenic emissions), and biogenic emissions, were quantified, making specific regulatory air quality management measures possible. EC originates nearly exclusively from fossil fuel usage during summer, whereas biomass‐burning emissions become substantial during winter with ∼25%, even though this source contributes only marginally to the local energy consumption. For OC, biogenic sources are dominant in summer with ∼60%, where secondary organic aerosol prevails. Wood combustion accounts for up to ∼41% of OC in winter. Fossil fuels represent ∼30% of OC throughout the year.
Sensitivity of the Atlantic Meridional Overturning Circulation to the melting from northern glaciers in climate change experiments
Authors: Swingedouw D. , Braconnot P. , Marti O.
Published: April 2006

A weakening of the Atlantic Meridional Overturning Circulation (AMOC) in the next century is simulated by most state‐of‐the‐art coupled models but none of them accounted for land‐ice melting. Here we evaluate the impact of this melting on future climate projection using the IPSL‐CM4 coupled ocean‐atmosphere model. For this purpose we use two different versions of the model, one with a crude land‐ice melting parameterization, and the other without. The analysis compares results of experiments where atmospheric CO2 increases by 1%/yr, performed with the two versions of this model. The AMOC is reduced by 47% when the melting of land‐ice is considered, and represents an extreme melting scenario. This reduction is of 21% without this melting. It is shown that this difference in AMOC impacts the northern hemisphere mostly through the sea‐ice cover feedback.
Completely explosive ultracompact high-voltage nanosecond pulse-generating system
Authors: Shkuratov Sergey I. , Talantsev Evgueni F. , Baird Jason , Rose Millard F. , Shotts Zachary , Altgilbers Larry L. , Stults Allen H.
Published: April 2006

A conventional pulsed power technology has been combined with an explosive pulsed power technology to produce an autonomous high-voltage power supply. The power supply contained an explosive-driven high-voltage primary power source and a power-conditioning stage. The ultracompact explosive-driven primary power source was based on the physical effect of shock-wave depolarization of high-energy Pb(Zr52Ti48)O3 ferroelectric material. The volume of the energy-carrying ferroelectric elements in the shock-wave ferroelectric generators (SWFEGs) varied from 1.2 to 2.6cm3. The power-conditioning stage was based on the spiral vector inversion generator (VIG). The SWFEG-VIG system demonstrated successful operation and good performance. The amplitude of the output voltage pulse of the SWFEG-VIG system exceeded 90kV, with a rise time of 5.2ns.
Molecular dynamics simulation of the nematic liquid crystal phase in the presence of an intense magnetic field
Authors: Satoh Katsuhiko
Published: April 2006

The influence of an intense external field on the dynamics of the nematic liquid crystal phase is investigated using a molecular dynamics simulation for the Gay-Berne nematogen under isobaric-isothermal conditions. The molecular dynamics as a function of the second-rank orientational order parameter ⟨P2⟩ for a system consisting of a nematic liquid crystal in the presence of an intense magnetic field is compared with that of a similar system without the field. The translational motion of molecules is determined as a function of the translational diffusion coefficient tensor and the anisotropy and compared with the values predicted theoretically. The rotational dynamics of molecules is analyzed using the first- and the second-rank orientational time correlation functions. The translational diffusion coefficient parallel with respect to the director is constrained by the intense field, although the perpendicular one is decreased as the ⟨P2⟩ is increased, just as it is in the system without the field. However, no essential effect of the strong magnetic field is observed in the rotational molecular dynamics. Further, the rotational diffusion coefficient parallel with respect to the director obtained from the first-rank orientational time correlation function in the simulation is qualitatively in agreement with that in the real nematic liquid crystalline molecules. The ⟨P2⟩ dependence of the rotational diffusion coefficient for the system with the intense magnetic field shows a tendency similar to that for the system without the field.
Scaling law of shear viscosity in atomic liquid and liquid mixtures
Authors: Musharaf Ali Sk.
Published: April 2006

A scaling law relating the shear viscosity of one and two component liquid mixtures to their excess thermodynamic entropies defined through pair correlation functions is derived by approximating the mode coupling theory expressions of frictions and then combining with the Stokes-Einstein relation. Molecular dynamics simulation has been performed to generate the data of shear viscosity for one and two component liquid mixtures to test the derived scaling law. The derived scaling laws yield numerical results of shear viscosity for one component and two component liquid mixtures, which are in excellent agreement with the molecular dynamics simulation results for a wide range of density and interaction potential.

At the request of the authors and editor, this article is being retracted 5 July 2006.
Modeling electrode polarization in dielectric spectroscopy: Ion mobility and mobile ion concentration of single-ion polymer electrolytes
Authors: Klein Robert J. , Zhang Shihai , Dou Shichen , Jones Brad H. , Colby Ralph H. , Runt James
Published: April 2006

A novel method is presented whereby the parameters quantifying the conductivity of an ionomer can be extracted from the phenomenon of electrode polarization in the dielectric loss and tanδ planes. Mobile ion concentrations and ion mobilities were determined for a poly(ethylene oxide)-based sulfonated ionomer with Li+, Na+, and Cs+ cations. The validity of the model was confirmed by examining the effects of sample thickness and temperature. The Vogel-Fulcher-Tammann (VFT)-type temperature dependence of conductivity was found to arise from the Arrhenius dependence of ion concentration and VFT behavior of mobility. The ion concentration activation energy was found to be 25.2, 23.4, and 22.3±0.5kJ∕mol for ionomers containing Li+, Na+, and Cs+, respectively. The theoretical binding energies were also calculated and found to be ∼5kJ∕mol larger than the experimental activation energies, due to stabilization by coordination with polyethylene glycol segments. Surprisingly, the fraction of mobile ions was found to be very small, <0.004% of the cations in the Li+ ionomer at 20°C.
Indium surfactant effect on AlN∕GaN heterostructures grown by metal-organic vapor-phase epitaxy: Applications to intersubband transitions
Authors: Nicolay S. , Feltin E. , Carlin J.-F. , Mosca M. , Nevou L. , Tchernycheva M. , Julien F. H. , Ilegems M. , Grandjean N.
Published: April 2006

We report on a dramatic improvement of the optical and structural properties of AlN∕GaN multiple quantum wells (MQWs) grown by metal-organic vapor-phase epitaxy using indium as a surfactant. This improvement is observed using photoluminescence as well as x-ray diffraction. Atomic force microscopy shows different surface morphologies between samples grown with and without In. This is ascribed to a modified relaxation mechanism induced by different surface kinetics. These improved MQWs exhibit intersubband absorption at short wavelength (2μm). The absorption linewidth is as low as 65meV and the absorption coefficient is increased by 85%.
Calculation of excitation energies of open-shell molecules with spatially degenerate ground states. II. Transformed reference via intermediate configuration Kohn-Sham time dependent density functional theory oscillator strengths and magnetic circular dichroism C terms
Authors: Seth Michael , Ziegler Tom
Published: April 2006

An extension of the transformed reference via an intermediate configuration Kohn-Sham time dependent density functional theory (TRICKS-TDDFT) method for calculating the transition energies of molecules with spatially degenerate ground states is proposed that enables oscillator strengths to also be evaluated. The oscillator strengths are calculated starting from a description of the degenerate ground state and the excited states of interest in terms of linear combinations of Slater determinants based upon the F-vectors obtained in the TRICKS-TDDFT calculation. This approach for calculating oscillator strengths can also be applied to several other properties that involve excited states. An example of such a property, the C term of magnetic circular dichroism (MCD), is presented. The new method is illustrated through example calculations of the absorbance and MCD spectra of several octahedral and C4v d5 transition metal complexes. The calculated transition energies and oscillator strengths are somewhat too low and too high, respectively, but these errors are within the range that would normally be expected for TDDFT calculations of this type. The calculations help to resolve some previously unexplained problems with the MCD spectra of the C4v complexes.
Structure and random anisotropy in single-phase Ni nanocrystals
Authors: Kita Eiji , Tsukuhara Naoki , Sato Hidenori , Ota Keishin , Yangaihara Hideto , Tanimoto Hisanori , Ikeda Naoshi
Published: April 2006

We prepared high-purity oxygen-free and single-phase Ni nanocrystals using the gas condensation and deposition method in order to examine the random anisotropy model (RAM). The grain size of an as-prepared sample was estimated to be 8–10nm. Thermal annealing increased grain sizes (D) up to 22nm. Clear D6 dependence of the coercive force on a grain size smaller than 13 nm was obtained for samples prepared on both plastic and KBr single-crystal substrates. For larger grain sizes, Hc decreased with D−1 and these results clearly conform to the RAM in single-element nanocrystal systems. A local anisotropy constant was estimated from the slope of the D6 relation and the peak of Hc at D=13nm.
Perturbation to the resonance modes by gold nanoparticles in a thin-film-based x-ray waveguide
Authors: Lee D. R. , Hagman A. , Li Xuefa , Narayanan S. , Wang Jin , Shull K. R.
Published: April 2006

We demonstrate, for the first time, that the resonance modes in a thin-film-based x-ray waveguide are extremely sensitive to the electron density distribution in the thin film. The resonance modes can be effectively altered by diffusion of a gold nanoparticle submonolayer embedded in the waveguide. Such a perturbation can be observed with dramatic change in x-ray reflectivity and fluorescence data in the low-angle (<0.5°) resonance regime. Conversely, the quantitative analysis of the perturbation to the resonance modes, x-ray reflectivity, as well as the resonantly excited x-ray fluorescence from gold nanoparticles can be exploited to accurately determine the absolute gold distribution within the profile of the thin-film-based waveguide with subnanometer resolution.
Electronic structures and electron-injection mechanisms of cesium-carbonate-incorporated cathode structures for organic light-emitting devices
Authors: Wu Chih-I , Lin Chan-Tin , Chen Yu-Hung , Chen Mei-Hsin , Lu Yin-Jui , Wu Chung-Chih
Published: April 2006

In this letter, we investigate electronic structures and electron-injection mechanisms of the effective cathode structures for organic light-emitting devices incorporating cesium carbonate (Cs2CO3), either deposited as an individual thin injection layer or doped into the organic electron-transport layers. The electronic structures and the interface chemistry studied by ultraviolet and x-ray photoemission spectroscopy show that the enhanced electron injection is associated with strong n-doping effects and increase of electron concentrations in the electron-transport layer induced by Cs2CO3. Since such a reaction occurs without the presence of metals, cathode structures incorporating Cs2CO3 may be applied to a wide range of electrode materials.
Extremely sharp carbon nanocone probes for atomic force microscopy imaging
Authors: Chen I-Chen , Chen Li-Han , Ye Xiang-Rong , Daraio Chiara , Jin Sungho , Orme Christine A. , Quist Arjan , Lal Ratnesh
Published: April 2006

A simple and reliable catalyst patterning technique combined with electric-field-guided growth is utilized to synthesize a sharp and high-aspect-ratio carbon nanocone probe on a tipless cantilever for atomic force microscopy. A single carbon nanodot produced by an electron-beam-induced deposition serves as a convenient chemical etch mask for catalyst patterning, thus eliminating the need for complicated, resist-based, electron-beam lithography for a nanoprobe fabrication. A gradual, sputtering-induced size reduction and eventual removal of the catalyst particle at the probe tip during electric-field-guided growth creates a sharp probe with a tip radius of only a few nanometers. These fabrication processes are amenable for the wafer-scale synthesis of multiple probes. High resolution imaging of three-dimensional features and deep trenches, and mechanical durability enabling continuous operation for many hours without noticeable image deterioration have been demonstrated.
P-doped p-type ZnO films deposited on Si substrate by radio-frequency magnetron sputtering
Authors: Wang P. , Chen NuoFu , Yin Z. G.
Published: April 2006

P-doped ZnO films were deposited on n-Si substrate by radio-frequency magnetron sputtering. Hall measurements revealed that the films annealed in situ at 750°C in an oxygen ambient at a pressure of 1.3×10−3–3.9×10−3Pa showed p-type behavior with a hole concentration of 2.7×1016–2.2×1017cm−3, a mobility of 4–13cm2∕Vs, and a resistivity of 10.4–19.3Ωcm. Films annealed at 750°C in a vacuum or in oxygen ambient at higher pressures (5.2×10−3 and 6.5×10−3Pa) showed n-type behavior. Additionally, the p-ZnO∕n-Si heterojunction showed a diodelike I-V characteristic. Our results indicate that P-doped p-type ZnO films can be obtained by annealing in oxygen ambient at very low pressures.
Time-domain response of point-defect cavities in two-dimensional photonic crystal slabs using picosecond light pulse
Authors: Asano Takashi , Kunishi Wataru , Song Bong-Shik , Noda Susumu
Published: April 2006

Time-domain responses of point-defect cavities in two-dimensional photonic crystal slabs are directly investigated. Point-defect cavities are excited by picosecond light pulses and time evolutions of the light emissions are measured by using cross-correlation method. The obtained signals clearly show delays in initial rises and tailings in later stages which reflect photon lifetimes of the cavities. The signals are analyzed by comparing with numerical simulations where Gaussian input pulses and linear responses of the systems are assumed. Photon lifetimes are evaluated to be <1, 3, and 9ps for the point-defect cavities having Q factors of 500, 3800, and 10 000, respectively. We believe that the results obtained here will contribute to the time-domain manipulation of photons utilizing artificial defects in photonic crystals.