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The seasonal predictability of the Rossby wave breaking (RWB) frequency near Japan in July–August (JA) is examined using daily JMA/MRI-CPS3 (CPS3) hindcast data, which is an operational seasonal prediction system of the Japan Meteorological Agency. Although the RWB frequency near Japan during JA in CPS3 is underestimated in comparison with the reanalysis, interannual variabilities of the frequency are generally predicted with moderate or high skill for hindcasts, initiating from February to June. The RWB frequency forecast skill in CPS3 is much higher than that in the previous version of the seasonal prediction system due to the improvement in the model bias of the Asian jetstream meridional position. A regression analysis for the RWB frequency near Japan utilizing all ensemble members is conducted to evaluate the reproducibility of the increased (decreased) RWB frequency associated with La Niña (El Niño) conditions, as indicated by previous studies. The regressed anomalies demonstrate an anomalous sea surface temperature (SST) pattern similar to that of La Niña and a negative phase of the Indian Ocean Dipole mode with the associated anomalous convection in the tropics. For the La Niña condition, the regressed geopotential height in the upper troposphere demonstrates negative anomalies over the tropical Pacific and positive anomalies in the extratropical Northern Hemisphere, corresponding to the enhanced mid-Pacific trough and northward-shifted subtropical jet. The regressed meridional wind anomalies demonstrate a wavy pattern along the Asian jet over Eurasia, consistent with the relationship between the Silk Road pattern and the RWB near the Asian jet exit region.

The Quasi-biennial Oscillation (QBO) dominates the interannual variability of the tropical stratosphere and influences other regions of the atmosphere. The high predictability of the QBO implies that its teleconnections could lead to increased skill of seasonal and decadal forecasts provided the relevant mechanisms are accurately represented in models. Here modelling and sampling uncertainties of QBO teleconnections are examined using a multi-model ensemble of QBO-resolving atmospheric general circulation models that have carried out a set of coordinated experiments as part of the Stratosphere-troposphere Processes And their Role in Climate (SPARC) QBO initiative (QBOi). During Northern Hemisphere winter, the stratospheric polar vortex in most of these models strengthens when the QBO near 50 hPa is westerly and weakens when it is easterly, consistent with, but weaker than, the observed response. These weak responses are likely due to model errors, such as systematically weak QBO amplitudes near 50 hPa, affecting the teleconnection. The teleconnection to the North Atlantic Oscillation is less well captured overall, but of similar strength to the observed signal in the few models that do show it. The models do not show clear evidence of a QBO teleconnection to the Northern Hemisphere Pacific-sector subtropical jet. We acknowledge the UK's Centre for Environmental Data Analysis (CEDA) for hosting the QBOi data archive. This work was supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under Cooperative Agreement no. 1852977. Portions of this study were supported by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S. Department of Energy's Office of Biological & Environmental Research (BER) via National Science Foundation IA 1844590. NB was supported by the Met Office Hadley Centre Programme funded by BEIS and Defra. SO and LG were supported by the National Centre for Atmospheric Science and the Natural Environment Research Council (NE/P006779/1, NE/N018001/1). FL and SO were supported by the JPI-Climate/Belmont Forum 423 project GOTHAM (ANR-15-JCLI-0004-01, NERC NE/P006779/1). CC and FS were supported by the Copernicus Climate Change Service, funded by the EU and implemented by ECMWF. HN was supported by the Environment Research and Technology Development Fund (S-12) of the Environmental Restoration and Conservation Agency of Japan and by Grant-in-Aid (JP18K03748, JP20H05171) for Science Research (KAKENHI) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. For the EMAC simulations, PB, TK, and SV acknowledge support by the state of Baden-Württemberg through bwHPC. YK was supported by the Japan Society for Promotion of Science (JSPS) KAKENHI (grant nos. JP15KK0178, JP17K18816, JP18H01286 and 19H05702) and by the Environment Research and Technology Development Fund (JPMEERF20192004) of the Environmental Restoration and Conservation Agency of Japan. YK and KH were supported by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) through its sponsorship of research at the International Pacific Research Center. SW and YK were partly supported by the “Integrated Research Program for Advancing Climate Models (TOUGOU program)” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The Earth Simulator was used for MIROC-ESM and MIROC-AGCM-LL simulations. We acknowledge the scientific guidance of the World Climate Research Programme (WCRP) for helping motivate this work, coordinated under the framework of the Stratosphere-troposphere Processes And their Role in Climate (SPARC) QBO initiative (QBOi) led by JA, NB, KH and SO. Peer Reviewed "Article signat per 29 autors/es: James A. Anstey, Isla R. Simpson, Jadwiga H. Richter, Hiroaki Naoe, Masakazu Taguchi, Federico Serva, Lesley J. Gray, Neal Butchart, Kevin Hamilton, Scott Osprey, Omar Bellprat, Peter Braesicke, Andrew C. Bushell, Chiara Cagnazzo, Chih-Chieh Chen, Hye-Yeong Chun, Rolando R. Garcia, Laura Holt, Yoshio Kawatani, Tobias Kerzenmacher, Young-Ha Kim, Francois Lott, Charles McLandress, John Scinocca, Timothy N. Stockdale, Stefan Versick, Shingo Watanabe, Kohei Yoshida, Seiji Yukimoto"

This study evaluates the latest Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) conducted by the Japan Meteorological Agency (JMA), focusing on a semi-period of pre-satellite era (1960s and 1970s). The reanalysis is the third Japanese global atmospheric reanalysis covering the period from late 1940s onward, which is produced with the JMA's operational system as of December 2018. The atmospheric model has a TL479 horizontal resolution and 100 vertical layers up to 0.01 hPa, and the core component of the JRA-3Q data assimilation system is the 6-hourly 4D-Var of the atmospheric state with a T319-resolution inner model. Because there are only few global-covered observational datasets during the pre-satellite era, evaluation of the JRA-3Q is mainly to conduct an intercomparison of other reanalysis datasets such as representation Japanese 55-year Reanalysis (JRA-55), a JRA-55's subset of atmospheric reanalysis assimilating conventional observations only (JRA-55C), and version 3 of the Twentieth Century Reanalysis (20CRv3), and also an intercomparison of JRA-3Q between the pre-satellite and satellite eras. Emphasis of this evaluation during the non-satellite era is placed on the representation of tropical circulation, the consistency in time of the reanalysed fields, detection of tropical cyclones, and the quality of the stratospheric water vapor and ozone. For example, the surface circulation over the tropical Africa is improved by means of reducing spurious anticyclonic circulation anomalies that were found in JRA-55. Although the atmospheric model can produce self-generated quasi-biennial oscillation (QBO) by introducing non-orographic gravity wave drag, the evaluation reveals that JRA-3Q has a shorter period of around one year in the middle stratosphere and diminished QBO amplitude in the lower stratosphere, indicating that representation of the QBO in JRA-3Q is not as good as that in JRA-55.

The present paper presents results of seasonal‐to‐decadal climate predictions based on a coupled climate model called the Model for Interdisciplinary Research on Climate version 6 (MIROC6) contributing to the Coupled Model Intercomparison Project Phase 6 (CMIP6). MIROC6 is initialized every year for 1960–2018 by assimilating observed ocean temperature and salinity anomalies and full fields of sea ice concentration and by prescribing atmospheric initial states from reanalysis data. The impacts of updating the system on prediction skill are then evaluated by comparing hindcast experiments between the MIROC6 prediction system and a previous system based on MIROC version 5 (MIROC5). Skill of seasonal prediction is overall improved in association with representation and initialization of El Niño/Southern Oscillation (ENSO), the Quasi‐Biennial Oscillation (QBO), and the Northern Hemisphere sea ice concentration in MIROC6. In particular, the QBO is skillfully predicted up to 3 years ahead with a maximum anomaly correlation exceeding r = 0.8. The prediction skill for the North Atlantic Oscillation in winter is also enhanced, but the prediction still suffers from model's inherent errors. On decadal timescales, MIROC6 has a larger fraction of areas of the globe with better surface temperature skill at all lead times than MIROC5, and it has predictive skill in the annual‐mean sea surface temperature (SST) in the North Atlantic and the Pacific. In particular, MIROC6 hindcasts at 2–5 years lead time are able to capture the spatial structure of SST changes in the North Pacific and the eastern tropical Pacific associated with the 1970s regime shift better than MIROC5 hindcasts.

A multi‐model study is carried out to investigate the ability of models to predict the evolution of the quasi‐biennial oscillation (QBO) up to 12 months in advance. All models are initialised from common reanalysis data, and forecasts run for a common set of 30 start dates over 15 years. All models have high skill in predicting the phase evolution of the QBO at 20–30 hPa, with slightly more variable results at higher and lower levels. Other aspects of the predicted QBO are of variable quality, and in some cases are consistently poor. QBO easterlies are too weak in all models at 20–50 hPa, while westerlies can be either too strong or too weak. This results in both a reduced amplitude of the QBO and a westerly bias in zonal‐mean winds, notably at 30 hPa. At 70 hPa models tend to have reduced QBO amplitude and an easterly bias. Despite these failings, a multi‐model ensemble of bias‐ and variance‐corrected forecasts can be used to give accurate and reliable QBO forecasts up to at least a year ahead. Analysis of the zonal momentum budget during the first month of the forecast shows that large‐scale forcing from Eliassen–Palm flux divergence and vertical advection are handled fairly well by the models, although vertical advection terms tend to be weaker than reanalysis estimates. Total tendencies show common errors, suggesting common failings in gravity‐wave drag treatments. Teleconnections from the QBO to Northern Hemisphere winter circulation are also examined, and do not appear to be realistic beyond the first month. Analysis of initialised forecasts is a powerful tool for diagnosing the accuracy of model processes driving the QBO.

The Quasi‐Biennial Oscillation initiative (QBOi) is a model intercomparison programme that specifically targets simulation of the QBO in current global climate models. Eleven of the models or model versions that participated in a QBOi intercomparison study have upper boundaries in or above the mesosphere and therefore simulate the region where the stratopause semiannual oscillation (SAO) is the dominant mode of variability of zonal winds in the tropical upper stratosphere. Comparisons of the SAO simulations in these models are presented here. These show that the model simulations of the amplitudes and phases of the SAO in zonal‐mean zonal wind near the stratopause agree well with the information derived from available observations. However, most of the models simulate time‐average zonal winds that are more westward than determined from observations, in some cases by several tens of m·s$^{–1}$. Validation of wave activity in the models is hampered by the limited observations of tropical waves in the upper stratosphere but suggests a deficit of eastward forcing either by large‐scale waves, such as Kelvin waves, or by gravity waves.

We compare the response of the Quasi‐Biennial Oscillation (QBO) to a warming climate in eleven atmosphere general circulation models that performed time‐slice simulations for present‐day, doubled, and quadrupled CO2 climates. No consistency was found among the models for the QBO period response, with the period decreasing by 8 months in some models and lengthening by up to 13 months in others in the doubled CO2 simulations. In the quadrupled CO2 simulations, a reduction in QBO period of 14 months was found in some models, whereas in several others the tropical oscillation no longer resembled the present‐day QBO, although it could still be identified in the deseasonalized zonal mean zonal wind timeseries. In contrast, all the models projected a decrease in the QBO amplitude in a warmer climate with the largest relative decrease near 60 hPa. In simulations with doubled and quadrupled CO2, the multi‐model mean QBO amplitudes decreased by 36 and 51%, respectively. Across the models the differences in the QBO period response were most strongly related to how the gravity wave momentum flux entering the stratosphere and tropical vertical residual velocity responded to the increases in CO2 amounts. Likewise it was found that the robust decrease in QBO amplitudes was correlated across the models to changes in vertical residual velocity, parametrized gravity wave momentum fluxes, and to some degree the resolved upward wave flux. We argue that uncertainty in the representation of the parameterized gravity waves is the most likely cause of the spread among the eleven models in the QBO's response to climate change.

The Quasi‐Biennial Oscillation initiative (QBOi) is a model intercomparison programme that specifically targets simulation of the QBO in current global climate models. Eleven of the models or model versions that participated in a QBOi intercomparison study have upper boundaries in or above the mesosphere and therefore simulate the region where the stratopause semiannual oscillation (SAO) is the dominant mode of variability of zonal winds in the tropical upper stratosphere. Comparisons of the SAO simulations in these models are presented here. These show that the model simulations of the amplitudes and phases of the SAO in zonal‐mean zonal wind near the stratopause agree well with the information derived from available observations. However, most of the models simulate time‐average zonal winds that are more westward than determined from observations, in some cases by several tens of m·s–1. Validation of wave activity in the models is hampered by the limited observations of tropical waves in the upper stratosphere but suggests a deficit of eastward forcing either by large‐scale waves, such as Kelvin waves, or by gravity waves.

The future quasi-biennial oscillation (QBO) in ozone in the equatorial stratosphere is examined by analyzing transient climate simulations due to increasing greenhouse gases (GHGs) and decreasing ozone-depleting substances under the auspices of the Chemistry–Climate Model Initiative. The future (1960–2100) and historical (1979–2010) simulations are conducted with the Meteorological Research Institute Earth System Model. Three climate periods, 1960–85 (past), 1990–2020 (present), and 2040–70 (future) are selected, corresponding to the periods before, during, and after ozone depletion. The future ozone QBO is characterized by increases in amplitude by 15%–30% at 5–10 hPa and decreases by 20%–30% at 40 hPa, compared with the past and present climates; the future and present ozone QBOs increase in amplitude by up to 60% at 70 hPa, compared with the past climate. The increased amplitude at 5–10 hPa suggests that the temperature-dependent photochemistry plays an important role in the enhanced future ozone QBO. The weakening of vertical shear in the zonal wind QBO is responsible for the decreased amplitude at 40 hPa in the future ozone QBO. An interesting finding is that the weakened zonal wind QBO in the lowermost tropical stratosphere is accompanied by amplified QBOs in ozone, vertical velocity, and temperature. Further study is needed to elucidate the causality of amplification about the ozone and temperature QBOs under climate change in conditions of zonal wind QBO weakening.

Two separate Asian dust events occurred before and after the passage of a cold front over Japan on 21 March 2010. According to back trajectories and a model simulation, the two dusty air-masses originated from the same region in Mongoria or northern China and were transported over different routes to Japan. Samples of aerosol particles from both airmasses were collected at Tsukuba and Mt. Haruna and examined by single-particle analysis using a transmission electron microscope and an energy dispersive X-ray analyzer. The mixing properties of mineral aerosol were quite different in the two airmasses and size ranges. In the prefrontal airmass, which were associated with pollution, most of fine (

We developed a polarization optical particle counter (POPC) for measuring the concentrations of aerosol types, which were classified using polarization information from particle-scattered light. Polarization sensors that detect P and S polarization components of scattered light were placed at a scattering angle of 120°. The polarization ratio is calculated as the ratio of the S component to the sum of the S and P components, and it is used to help distinguish proposed aerosol types. The POPC field observation was conducted in Fukuoka, located in the western part of Japan, in 2012. The classification rule for three aerosol types (mineral dust, air pollution, and sea-salt particles) was determined empirically on the basis of measurements during typical conditions dominated by each aerosol type. The mass concentration of each aerosol type was estimated from the POPC measurement with some assumptions. The results indicate independent seasonal variation in each aerosol mass concentration. Using black carbon as an indicator of anthropogenic aerosols, we show a correlation of 0.770 with our estimated pollution aerosol type.

Aerosols in the lower troposphere over Japan are considered being influenced by those transported from Asian continent by westerly winds. In this study, we investigated the seasonal variation of aerosol number concentrations measured by means of optical particle counters at Mt. Kiso-Komagatake (2610 m altitude) in central Japan during the period from January 2010 to May 2013. We also collected aerosol samples in different seasons during part of the observation period and investigated their elemental compositions using transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDX). The seasonal variation of the number concentrations suggested that accumulation-mode particles (particle diameter > 0.3 μm) increased during late spring perhaps owing to gas-to-particle conversion by means of photochemical reactions. The number concentrations of supermicron particles (>1 μm) were highest in spring, during which Asian dust events were frequent. Short-duration spikes in aerosol number concentrations, which were attributed to long-range transport from the Asian continent, were frequently observed in all seasons except summer. TEM analysis indicated that sulfate was the predominant component of accumulation-mode particles throughout the year. The number fraction of carbonaceous particles was also considerable, especially in samples in fall. The predominant components of supermicron particles collected during winter, spring and fall, and summer were sulfate, minerals, and sea salt, respectively. Our results suggest that the lower tropospheric air over central Japan is strongly influenced by long-range transport of aerosols in all seasons except summer.

The high plateaus in west China may provide suitable sites for astronomical observations with theinstitute’s middle-range telescopes and possibly with larger telescopes. Under China-Japan collaborationsfor site survey in west China, we have been conducting searches for good sites and monitoring theircharacteristics over several years. As recent results of our site survey show, sites in west Tibet arerevealed with a high possibility of good astronomical observations.Weather characteristics at Gar in Ali, Tibet, show its high clear-sky ratios, especially in winter, com-parable to Mauna Kea, Hawaii. But it has some wind problem in winter, where stronger wind speeds,over 20m/sec, occur frequently even though the sky is clear. To nd calmer sites, we have conductednumerical simulations for the Ali area using the Japan Meteorological Agency NonHydrostatic Model.We have found another site, named ZoZo Hill, near Gar. We will continue to monitor the Gar site toclarify weather characteristics over the whole year and hopefully start to negotiate for site monitoring atZoZo Hill this year.Key words: international collaboration, site test, telescope site, west Tibet1. WEST TIBET AS AN IMPORTANT LONGITUDI-NAL LOCATION FOR GLOBAL ASTRONOMICALOBSERVATION NETWORKAs west China is indicating its importance in playinga role for the global astronomical observation network(Yao 2005), we have been conducting astronomical site-monitorings at three sites in west China; Karasu (Xin-jiang Uighur), Oma (Tibet) and Gar/Ali (Tibet) undera China-Japan Astronomical Collaboration since 2007(Sasaki et al., 2008; Yao et al., 2011; Sasaki et al., 2011).2. ASTRONOMICAL SITE MONITORINGSeveral astronomical site-monitoring instruments havebeen deployed at the sites. At the Oma and Gar site,cloud monitoring cameras have revealed excellent skyconditions, especially in winter. Gar has shown betterweather conditions than Oma.On the other hand, strong winds that have been ob-served at the current monitoring site, Gar, in winter mayseriously a ect the number of observable nights (Figure1), as the imaging capabilities of telescope optics wouldbe reduced due to turbulence caused by stronger windhttp://pkas.kas.orginside the telescope dome by applying the criteria forwind speed

Longer-term (i.e., 20–40 years) tropospheric ozone (O3) time series obtained from surface and ozonesonde observations have been analyzed to assess possible changes with time through 2010. The time series have been selected to reflect relatively broad geographic regions and where possible minimize local scale influences, generally avoiding sites close to larger urban areas. Several approaches have been used to describe the changes with time, including application of a time series model, running 15-year trends, and changes in the distribution by month in the O3 mixing ratio. Changes have been investigated utilizing monthly averages, as well as exposure metrics that focus on specific parts of the distribution of hourly average concentrations (e.g., low-, mid-, and high-level concentration ranges). Many of the longer time series (∼30 years) in mid-latitudes of the Northern Hemisphere, including those in Japan, show a pattern of significant increase in the earlier portion of the record, with a flattening over the last 10–15 years. It is uncertain if the flattening of the O3 change over Japan reflects the impact of O3 transported from continental East Asia in light of reported O3 increases in China. In the Canadian Arctic, declines from the beginning of the ozonesonde record in 1980 have mostly rebounded with little overall change over the period of record. The limited data in the tropical Pacific suggest very little change over the entire record. In the southern hemisphere subtropics and mid-latitudes, the significant increase observed in the early part of the record has leveled off in the most recent decade. At the South Pole, a decline observed during the first half of the 35-year record has reversed, and O3 has recovered to levels similar to the beginning of the record. Our understanding of the causes of the longer-term changes is limited, although it appears that in the mid-latitudes of the northern hemisphere, controls on O3 precursors have likely been a factor in the leveling off or decline from earlier O3 increases.

Individual aerosol particles collected by a two-stage impactor on Mt. Hotaka (2165 m altitude) in central Japan in winter are studied using a transmission electron microscope and an energy-dispersive X-ray (EDX) analyzer. The size, morphology, elemental composition, mixing state and relative abundances are examined for (~ 550 ) aerosol particles with sizes of 0.1–2.0 μm collected during winter monsoon. Further smaller fine-ultrafine (~ 920) particles with sizes of 0.02–0.5 μm are also studied by electron-beam bombardment. There are potassium-containing sulfur particles, which may be originated from biomass burning or biofuel combustion in the Asian continent; sulfur would accumulate on these particles during their transport. Mineral particles and soot-containing particles constitute the minor abundance (less than 10% of all the particles). The samples collected during snowfall contain a very high fraction (> 90%) of fine sulfur-rich particles and no coarse particles are collected; precipitation may scavenge these coarse particles from the atmosphere. The electron-beam bombardment analysis reveals that the most abundant particles are the electron-beam sensitive (damaged) particles, which account for 70–90% of the total particles. On the basis of the comparison of fine particles with the diameter ranges of 0.1–0.5 μm obtained by both the EDX analysis and electron-beam bombardment analysis, the electron-beam sensitivity/insensitive particles would correspond to sulfur-containing particles/soot or mineral particles although we cannot deny out other particles such as nitrate, organics.

Aerosol number concentrations were continuously measured at sites at Tsukuba and Mt. Haruna on the Kanto region of Japan by using optical particle counters (OPCs) from February to June 2007. Three specific dust events captured at the sites were analyzed by using lidar, backward trajectories, and model simulation in detail. The temporal variations in aerosol concentrations in the two Asian-dust events (K1 event: 31 March–3 April; K2 event: 25–28 May) were similar. Dust particles (≥2.0 μm in diameter) were transported in association with a synoptic-scale cold front, and they arrived at the Tsukuba site about 8 h after they were observed at the Mt. Haruna site, in association with the dissipation of a local front formed ahead of the cold front. However, the inflow patterns of dust particles differed between the K1 and K2 events. The K1 event flowed onto the Kanto Plain, detouring around the mountainous region, whereas the K2 event directly flowed across the mountains. The difference in inflow pattern was probably due to the blocking effects of the mountains and the formation of a stable layer near the surface. Preceding the dust plume arrival, an increase in the number concentration of small-aerosol particles (0.3–1.0 μm in diameter), which are considered to be spherical by lidar, was observed, but only at the Tsukuba site. This increase was possibly due to anthropogenic pollution transported over long distances from the continent and from domestic sources in the Kanto region. The third event was a local dust event, because it was observed only at the Tsukuba site (on 13 and 14 March) under dry conditions ( 10 m s −1 ).

As a part of the effort to understand the structure of long-range transported aerosol plumes and local pollution, aerosol observations monitored the mass concentrations and number-size distributions during the period August 2006 to July 2009 near the top of Mt. Haruna (1365 m), an isolated mountain in the Kanto Plain in Japan. The mass concentrations observed at Mt. Haruna and plain sites showed a seasonal variation with a maximum in spring and summer, respectively. The spring peaks in aerosols at Mt. Haruna were probably caused by long-range transport of mineral dust and anthropogenic particles from the Asian continent. The summer peaks at the plain sites was attributed to local pollution from the Tokyo metropolitan area. Three examples of 2007 Asian dust events were investigated to show that aerosols may be dispersed in a complicated three-dimensional structure and that delayed arrivals of the dust plumes at plain sites compared to Mt. Haruna were not a rare case. Because of the boundary layer being stable at night, the dust layer was advected eastward without the vertical mixing before sunrise. This study suggests that after thermal convection activated by sunlight during daytime Asian dust transported in the free troposphere may be brought down into the atmospheric boundary layer, increasing the dust concentration there.

The state of mixture of light-absorbing carbonaceous particles was investigated in relation to light absorption properties using electron microscopic examinations, black carbon (BC) analyses of quartz filter by thermal/optical reflectance (TOR) method, measurements with two continuous light-absorbing photometers at a suburban site of Tsukuba, about 60 km northeast of Tokyo. The volume fraction of water-soluble material ( ɛ ) in individual particles is important for assessing particulate light-absorbing and/or scattering of atmospheric aerosols. The values of ɛ in BC particles were evaluated by electron micrographs before and after dialysis (extraction) of water-soluble material. The mass absorption coefficient (MAC in units of m 2 g −1 ) tended to increase with increasing the average ɛ in BC particles with the radius range of 0.05–0.5 μm. Thus, our results indicate that coatings of water-soluble material around BC particles can enhance the absorption of solar radiation. Moreover, the single scattering albedo (SSA) will increase because a large amount of coating material will scatter more light.

遠洋上にある南鳥島(24.3°N, 154.0°E)で1993年2月から3月にかけて海洋性エアロゾル粒子を9試料採集した。電子顕微鏡に付属のエネルギー分散型X線分析器を用いて、半径範囲0.4-2.0 μmの個々のエアロゾル粒子について各試料あたり約100個の粒子の元素組成を分析した。その結果、89%から98%は海塩粒子で、硫黄が多く含まれた粒子や鉱物粒子はともに3%の個数割合であった。海塩粒子のうち5%はCl/Naの重量比が1以下であった。これは塩素が不足し粒子が変質したことを示している。変質した海塩粒子が25%も占めた試料があり、このときの流跡線はアジア大陸に近接した海洋大気から輸送されていた。人間活動で汚染された空気塊が長距離輸送されたとき、非均質反応によって海塩粒子が変質したと考えられる。

An aerosol observation campaign was conducted at the summit of Mt. Fuji (at an altitude of 3776 m), which is located 170 km northwest of Miyakejima. Individual aerosol particles were collected with an electrostatic aerosol sampler and the number–size distribution and composition were examined by electron microscopy. Number–size distributions were measured with the combination of a diffusion battery (DB) and a condensation particle counter. Sulfate and sulfur dioxide concentrations were also determined. During the first half of the campaign (13–15 September 2000), high number fractions of sulfuric-acid containing particles with a mode radius around 0.06 μm were observed in the radius range of 0.02–0.2 μm coincident with a humid maritime air mass originated from the south. Sulfate and sulfur dioxide also showed high concentrations in this period. These results suggested that the volcanic plumes of Miyakejima were transported up to the summit of Mt. Fuji. Number–size distributions determined by electron microscope were consistent with those derived using the DB. During the later half of the experiment (18–20 September), low fractions of sulfuric-acid containing particles represented only a small fraction of the total particle number, coincident with a dry continental air mass originating from the west.

In the present study it is attempted to explain the mechanism of blocking formation in the Atlantic in connection with Rossby wave propagation from the upstream side. For this purpose, assuming a realistic monthly-mean non-blocking basic flow, the nondivergent vorticity equation on the sphere is numerically time-integrated in the linear and nonlinear models, with steady and non-steady (traveling) forcings located in the southern side of the North Atlantic jet. Our numerical experiment can reproduce a blocking formation as follows. When the Rossby wave induced by traveling forcing propagates along a North Atlantic jet and the portion of the anticyclonic vorticity in the Rossby wavetrain reaches high latitudes (near 60°N), its amplitude is increased in the jet exit region. This process can be understood as a linear evolution, since it can be simulated by the linear model also. After this process, the meridional separation of induced anomalies takes place and the blocking flow is formed as a distinct dipole structure with positive anomaly (i.e., negative vorticity) northward and negative anomaly (i.e., positive vorticity) south of it, so that the blocking flow becomes quasi-stationary. This process cannot be simulated by the linear model. Therefore, nonlinear effects are considered to play a critical role in this process.

In this study, we examine the nonlinear effect in the evolution of the Rossby wave propagating in the jet stream using a nonlinear barotropic model. We focus primarily on the formation of isolated eddy from the Rossby wave. The Rossby wave is induced by localized vorticity forcing in a zonally-varying basic flow. For weak, steady forcing we obtain the Rossby wavetrain trapped in the jet stream, as in the linear model. For strong, steady forcing it is occasionally seen that an isolated eddy with negative vorticity is formed from some domain in the Rossby wavetrain, when the zonal asymmetry of the basic flow is large. For strong forcing of a finite period, a strong isolated eddy with negative vorticity can be formed from some domain when the zonal asymmetry of basic flow is large. This eddy breaks down to finally emanate Rossby wave downward.

The Rossby wave propagation in various basic flows is studied, based on the numerical time-integration of a barotropic model on the sphere. First, the propagation in idealized basic flows is examined. When the zonally uniform basic flow has a strong jet, the jet stream acts like a waveguide for the Rossby wave. When the basic flow has a component of zonal wavenumber 1 (or 2), the Rossby wave emanating from the entrance region of the jet rapidly propagates eastward to the jet exit region. Then, the wave becomes stagnant and its amplitude is increased in the exit region. When the wave component superposed in the basic flow is strong, the basic flow has barotropically unstable modes. Nevertheless, this instability is weak so that the propagation patterns are not influenced by it. The barotropic conversion of kinetic energy from the basic field is evaluated to be important in this wave amplification in the jet exit region. Then, it can be understood that this wave amplification is produced both by the stagnation of wave energy from the energy source and by the subsequent barotropic conversion in the jet exit region. Second, the wave propagation is examined for monthly-mean basic flows derived from wintertime observational data. It is found that the propagation property of the Rossby wave is highly dependent on the basic wind distribution. In one case (December 1986) the Rossby wave, which has propagated eastward through the Asian jet, is blocked and becomes stagnant near the jet exit region. In contrast, in the other case (January 1984) near the jet exit the propagation path splits into eastward and equatorward paths.

Polarization optical particle counter (POPC) capable of measuring particle shape or sphericity was developed, which uses detection of polarization of light scattered by particles. Sensors that detected P and S polarization components are incorporated at scattering angle of 120˚ in addition to ordinary sensor located at the angle of 60˚. The particle size is derived from the pulse height detected with the ordinary sensor. The size thresholds were determined by measurements of PSL standard particles. Polarization of particle is calculated as the ratio of S polarization component to the sum of all components. The POPC field observations were started in Fukuoka, Japan on 15 March 2012 and in Matsue, Japan on 28 February 2012. Air pollution with high particle number concentration was observed in Fukuoka on 11 April. In that time, the particles with polarization lower than 0.3 constituted 90% of particles in the size range from 0.5 µm to 3 µm and 70-90% of those from 3 µm to 5 µm. Most of the atmospheric aerosol particles were consisted of spherical particles. Significant Asian dust transport was observed in Fukuoka on from 31 March to 1 April. The particles with polarization lower than 0.3 constituted 80% of those from 0.5 µm to 1 µm, 55-65% of those from 1 µm to 5µm. The increase of the ratio of non-spherical particles to all particles in Asian dust event was confirmed. The POPC thus is capable of measuring particle shape as well as size for each individual particle.

[1] The effect of climate change on the dynamics of the Holton-Tan (HT) relationship (i.e., the influence of the quasi-biennial oscillation (QBO) on extratropical circulation) is examined for a set of three-member simulations and a sensitivity simulation with constant greenhouse gases (GHGs) at 1960 levels, focusing on the Northern Hemisphere extended winter. The simulations are conducted by the MRI chemistry climate model (MRI-CCM), which internally generates the QBO; the set is driven by the REF-B2 scenario from 1960 through 2100, and constant GHG simulation by the same halogen scenario and fixed greenhouse gases. Future climate change results in a colder stratosphere with a temperature decrease of 6 K and with a westerly increase of ∼4 m s−1. Although the HT relationship is present in early winter in the recent climate interval from 1960 through 1999 in the ERA-40 reanalysis data and the simulation, the HT relationship in the future climate interval from 2060 through 2099 is predicted to be stronger in late winter. The analysis of the constant GHG simulation indicates that the HT relationship holds for the future in which forcings are almost constants and possible contributions to the HT effect are due to long-term natural variability. Further, we suggest that the climate change, or the increase in the atmospheric CO2, is responsible for the regime shift between the current climate interval and the future climate interval in the REF-B2 scenario. Further research is required to determine how a multidecadal oscillation could modulate the HT effect.

To clarify the localization and characterization of dystrophin and dystrophin-related protein (DRP) in the human central nervous system (CNS), we carried out immunoblotting and immunostaining studies using three region-specific anti-dystrophin and one anti-DRP antibodies. With immunostaining, punctuate immuno-reactivity of dystrophin was seen along the cell bodies and dendrites of the cerebral cortical neurons and cerebellar Purkinje cells in the normal controls autopsied. By contrast, dystrophin was not detected at all in the CNS of Duchenne muscular dystrophy (DMD) patients with intellectual disturbance. Immunoreactivity of DRP was observed in the vascular walls of both normal and DMD brains, but not in the neuronal cells. Compensatory increase of DRP was not noted in DMD brains. This study suggests that in DMD the brain-type dystrophin originally present in neurons is absent and may be related to the intellectual disturbance.

[1] This study examines the influence of stratospheric quasi-biennial oscillation (QBO) on the polar vortex (hereafter referred to as Holton-Tan relationship) in the Northern Hemisphere (NH) and investigates the mechanism of the Holton-Tan relationship, such as its beginning process and its interaction between the equatorial QBO and the tropospheric circulation, focusing on the connections between the QBO and the tropospheric circulation in the NH autumn. The National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis (NCEP/NCAR) and NCEP-DOE Reanalysis II data sets are used in the analysis over a 25 year period from September 1980 to February 2005. In the zonally averaged field, easterly (westerly) anomalies at high latitudes (50°N–75°N), westerly (easterly) anomalies at midlatitudes (around 30°N–50°N), and easterly (westerly) anomalies at subtropical latitudes (around 10°N–30°N) are present, extending vertically throughout the atmosphere in NH autumn (September–November) during the easterly (westerly) phase of the QBO. The composite difference in the Eliassen-Palm (EP) flux divergence is consistent with observed mean flow tendencies near the tropopause in midlatitude and high-latitude stratosphere in autumn, indicating that atmospheric waves play a crucial role in the formation of zonal wind anomalies. The Holton-Tan relationship also begins to appear around late October and becomes clearer with intraseasonal March. There are significant vertical velocity anomalies from the troposphere through the lower stratosphere at low and middle latitudes in association with the convergence anomalies of the EP flux when the QBO is in the easterly phase. These results suggest that the stratospheric QBO is connected with tropospheric circulation through wave activities and the associated meridional circulation in NH autumn.

[1] This study investigated the Holton-Tan relationship between the equatorial quasi-biennial oscillation (QBO) and the polar vortex as seen in the ERA-40 reanalysis and ERA-interim analysis (1980–2004, 25 years) data sets and in ensemble simulated data sets (five members covering the period 1980–2004, 125 years) by using the Meteorological Research Institute chemistry climate model (MRI-CCM) and focusing on the Northern Hemisphere winter. The primary tools employed were composite differences in zonal wind, temperature, and Eliassen-Palm (EP) fluxes. Although not many global circulation models can simulate the QBO realistically, the MRI-CCM, which includes the interaction between QBO dynamics and the ozone (hence heating) distribution, reproduces a self-generated QBO that is fairly realistic. In agreement with the finding of previous studies, our results revealed that the conventional Holton-Tan explanation that the equatorial winds in the lower stratosphere act as a waveguide for midlatitude planetary wave propagation cannot explain the winter circulation in either the ERA-40 data or the simulation. Although the composite differences in zonal wind and temperature show a slight yet statistically significant Holton-Tan effect, i.e., the stratospheric polar vortex is weaker and more disturbed under easterly QBO conditions, the EP flux diagnostics do not show more poleward propagation in the midlatitude stratosphere. Rather, planetary waves propagate more equatorward as well as more upward during the easterly phase of the QBO.

The concentrations of 18 soluble inorganic species were determined in the surface water samples of Lake Teganuma, periodically collecting at three points in the lake and three points at the rivers entering into the lake, from Dec. 1988. Vertical distributions of them in the lake were also examined using a simple glass tube with stop cocks. Some characteristics of them were discussed in relation to their sources and biological activities.

Six antineutrophil antibody (ANA)-positive patients with copper deficiency were classified into two groups; those with (group A, n = 3) and those without (group B, n = 3) neutropenia. The percent binding of ANA for normal peripheral neutrophils was similar in both groups (83.5 +/- 7.2 vs. 79.1 +/- 10.5%). The percent binding of sera to cultured promyelocytic leukemia cells (HL-60) was increased in group A (from 3.7 +/- 3.2 to 12.2 +/- 2.3%) but not in group B (from 65.3 +/- 21.7 to 40.7 +/- 6.3%) after stimulation of HL-60 with DMSO. The stimulated HL-60 cells expressed CD 16 and CD 11b antigens. In the presence of monoclonal antibody for CD 16, the titer of ANA was nil in group A and unchanged in group B. Thus, ANA of patients with neutropenia may recognize mainly the CD 16 antigen, the Fc gamma receptor III of neutrophils.

Single muscle fibers, obtained at autopsy from a 22-year-old man with Duchenne muscular dystrophy were examined immunocytochemically and also using polymerase chain reaction (PCR). Dystrophin-positive cells were widespread in skeletal, cardiac, smooth muscle, and in brain cells. PCR and Southern blot analyses of DNA from peripheral blood lymphocytes revealed a deletion of exon 45 in the dystrophin gene. With PCR of single fibers, three bands corresponding to exons 44, 45, and 47 were present in the normal control muscle fibers and dystrophin-positive fibers from the patient, while only two bands, exons 44 and 47, were observed in dystrophin-negative fibers. Therefore, in this patient, the genotype of dystrophin-positive fibers differed from that of the dystrophin-negative fibers, possibly because of a somatic mosaicism for deletion in the dystrophin gene. A mutation of the dystrophin gene may have occurred in one cell at an early stage of ontogenesis.

To clarify the localization and characterization of dystrophin and dystrophin-related protein (DRP) in the brains of normal and mdx mice, we carried out immunostaining and immunoblotting studies using four region-specific antidystrophin and anti-DRP antibodies. With immunostaining, punctate immunoreactivity of dystrophin was seen along the cell bodies and dendrites of the cerebral cortical neurons in the normal mice. By contrast, dystrophin was not detected at all in the brains of mdx mice. Immunoreactivity of DRP was observed in the vascular walls, pia mater, and choroid plexus of both normal and mdx brains, but not in the neuronal cells. The possible compensatory increase of DRP as seen in the skeletal muscles of mdx mice was not noted in the brains. The immunoblot findings were very consistent with those of immunostain. Although further studies of brain-type dystrophin are necessary, it seems unlikely that DRP participates in any physiological function of the neuronal cells. © 1994 John & Sons, Inc.

The aim was to localise and characterise dystrophin in various human tissues, especially in the CNS. Immunoblotting and immunostaining studies were carried out with eight region-specific dystrophin antibodies. In necropsy tissue from controls, dystrophin was noted as a doublet in immunoblots of striated muscle, and as a single band in those of smooth muscle and the CNS. With immunostaining, punctate immunoreactivity was seen on the cell bodies and dendrites of the cerebral cortical neurons and cerebellar Purkinje cells. By contrast, dystrophin was not detected in any tissues, including the cerebrum and cerebellum, of patients with Duchenne muscular dystrophy who had an intellectual disturbance.