An Observational Study of the 30-50 Day Atmospheric Oscillations Part I: Structure and Propagation

Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the equatorial region. Those in the mid-high latitudes, however, are revealed to be very different from the tropics and pose a strong barotropic structure. Horizontal coherence shows teleconnection patterns which can be identified as EAP and PNA. The wind field of the specified time scale of the oscillation appears as long-lived vortices and vortex pairs. Mid-latitude perturbations propagate clearly westwards, especially during the winter season. In the high latitudes, they propagate westwards in the winter but eastwards in the summer. Meridional propagations are rather different from region to region.

Improvement of 6–15 Day Precipitation Forecasts Using a Time-Lagged Ensemble Method

A time-lagged ensemble method is used to improve 6-15 day precipitation forecasts from the Beijing Climate Center Atmospheric General Circulation Model,version 2.0.1.The approach averages the deterministic predictions of precipitation from the most recent model run and from earlier runs,all at the same forecast valid time.This lagged average forecast （LAF） method assigns equal weight to each ensemble member and produces a forecast by taking the ensemble mean.Our analyses of the Equitable Threat Score,the Hanssen and Kuipers Score,and the frequency bias indicate that the LAF using five members at time-lagged intervals of 6 h improves 6-15 day forecasts of precipitation frequency above 1 mm d-1 and 5 mm d-1 in many regions of China,and is more effective than the LAF method with selection of the time-lagged interval of 12 or 24 h between ensemble members.In particular,significant improvements are seen over regions where the frequencies of rainfall days are higher than about 40％-50％ in the summer season; these regions include northeastern and central to southern China,and the southeastem Tibetan Plateau.

A Further Inquiry on the Mechanism of 30-60 Day Oscillation in the Tropical Atmosphere

In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heating can excite the CISK-Kelvm wave and CISK-Rossby wave in the tropical atmosphere and they are all the low-frequency modes which drive the activities of 30-60 day oscillation in the tropics. The most favorable conditions to excite the CISK-Kelvin wave and CISK-Rossby wave are indicated: There is convection heating but not very strong in the atmosphere and there is weaker disturbance in the lower troposphere.The influences of vertical shearing of basic flow in the troposphere on the 30-60 day oscillation in the tropics are also discussed.

An Observational Study of the 30-50 Day Atmospheric Oscillations Part II: Temporal Evolution and Hemispheric Interaction across the Equator

In this part, the temporal evolution and interaction across the equator of 30-50 day oscillation in the atmosphere are investigated further. The annual variation of 30-50 day oscillation is quite obvious in the mid-high latitudes. In the tropical atmosphere, the obvious interannual variation is an important property for temporal evolution of 30-50 day oscillation. The low-frequency wavetrain across the equator over the central Pacific and central Atlantic area, the movement of the long-lived low-frequency system across the equator and the meridional wind component across the equator will obviously show the interaction of 30-50 day oscillation in the atmosphere across the equator.

CISK-rossby wave and the 30-60 Day Oscillation in the Tropics

The 30-60 day oscillation is an important aspect of the atmospheric variance in the tropical area. A number of works have been done on this phenomenon, this article is a further one. A quasi-geostrophic linear model that consists of a two-layer free atmosphere and a well-mixed boundary layer is used to investigate the instability of intraseasonal oscillation, its propagation and vertical structures. Results show that the dynamical coupling and interaction between the barotropic and baroclinic components via boundary layer convergence / divergence are responsible for the appearance of a new kind of low-frequency wave. Such wave is very different from the traditional tropical Rossby wave. It can propagate westward and eastward. Some behaviours of it appear to resemble the observed 30-60 day oscillation mode in many aspects, such,as vertical structures, zonal and meridional propagations. Now many researchers emphasize the direct relationship between CISK-Kelvin mode and the tropical atmospheric 30-60 oscillation. It is considered that CISK-Rossby mode should not be neglected.

STUDY ON DYNAMICS OF TROPICAL CISK-ROSSBY WAVES AND MECHANISM OF 30-50 DAY OSCILLATIONS

To add to the growing mature research on the tropical 30-50 day oscillations from a new prospective, the current work bases on dynamic analysis of baroclinic quasi-geostrophic models to discuss dynamic mechanisms for the generation and propagation of CISK-Rossby waves, and to understand restraints and effects of different wave structures and thermodynamic forcing on the 30-50 day oscillations in the tropical atmosphere. Some important properties of the oscillation propagation have been explained and, in detail, with respect to its meridional propagation and vertical "baroclinic" structure. The work has come up with some new opinions and viewpoints. New opinions about the propagation and energy dispersion are to be proved by more observations and study.

The Characteristics of 30-60 Day Oscillation and Its Relations to the Interannual Oscillations

The characteristics of 30-60 day oscillation (hereafter called LFO ) of the outgoing longwave radiation data (OLR) and its relations to the interannual oscillations of the sea surface temperature (SST) are investigated by using the daily OLR data for the period from January, 1979 to December, 1987 and the corresponding monthly SST data. It is found that the LFO the band the interannual oscillations of the SST monthly anomaly (SSTA) interact each other and they all relate to the occurrence and development of El Nino events closely. Before El Nino event happens, it contributes to the SST's wanning up and to the SST's quasi-biennial oscillation (called QBO for brevity) and three and half years oscillation (called SO for short) being in warm water phase in the equatorial central and eastern Pacific (ECP and EEP) that the LFO in the equatorial western Pacific (EWP) enhances and propagates eastward; When El Nino event takes place, the LFO, SSTA and SSTA's QBO and SO in the EEP interact and strengthen each other; But the warmer SST and the SSTA's QBO and SO in the warm water phase in the EEP contribute to the LFO's weakening in the equatorial Pacific. Moreover, these contribute to the SST in the EEP becoming cold and the SSTA's QBO and SO in the EWP being in cold water phase and then impel the El Nino event to end.

Video-based measurement and data analysis of traffic flow on urban expressways

A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.

RELATIONSHIP BETWEEN THE 30 TO 60 DAY OSCILLATION OF ATMOSPHERIC HEAT SOURCE AND THE DROUGHT AND FLOOD EVENTS IN JUNE IN THE SOUTH OF CHINA

Based on the NCEP/NCAR reanalysis data and the observed precipitation data in the south of China from 1958 to 2000,the impact of 30 to 60 day oscillation of atmospheric heat sources on the drought and flood events in June in the south of China is discussed.During the flood(drought) events,there exists an anomalous low-frequency anticyclone(cyclone) at the low level of the troposphere over the South China Sea and the northwestern Pacific,accompanied with anomalous low-frequency heat sinks(heat sources),while there exists an anomalous low-frequency cyclone(anticyclone) with anomalous heat sources(sinks) over the area from the south of China to the south of Japan.On average,the phase evolution of the low-frequency in drought events is 7 to 11 days ahead of that in flood events in May to June in the south of China.In flood events,low-frequency heat sources and cyclones are propagated northward from the southern South China Sea,northwestward from the warm pool of the western Pacific and westward from the northwestern Pacific around 140°E,which have very important impact on the abundant rainfall in June in the south of China.However,in drought events,the northward propagations of the low-frequency heat sources and cyclones from the South China Sea and its vicinity are rather late compared with those in flood events,and there is no obvious westward propagation of the heat sources from the northwestern Pacific.The timing of the low-frequency heat source propagation has remarkable impact on the June rainfall in the south of China.

Effect of cooling rate on evolution of superconducting phases during decomposition and recrystallization of (Bi,Pb)-2223 core in Ag-sheathed tape

The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.

Mesmerism, Sexuality, and Medicine：＂Karezza＂ and the Sexual Reform Movement

Within the scope of certain social and religious movements, mesmerism had a considerable impact on the Americanway of life during the last decades of 19th century. A famous example is the Christian Science of Mary Baker EddyBut also less known groups adopted mesmeric ideas and practices. The paper focuses on the concept of＂Karezza＂.It combined a specific sexual practice with religious ideas of divine love, birth control, social reform, women＇semancipation and health education. It was created by Alice Bunker Stockham （1833-1912）, an obstetrician andgynecologist from Chicago. Among other authorities, the writer Leo Tolstoy and medical psychologist HavelockEllis appreciated her approach. She was a pioneer of the sexual and marriage reform promoting practical advice foreveryday life. As a doctor, she stressed especially the disastrous consequences of a brutal sexual life destroyingbody and mind （not only of the women）. As an antidote, she propagated the ＂Karezza love＂ avoiding ejaculation ada punctual orgasm （climax） during intercourse. The leading idea was the imagery of a mesmeric ＂fluidum＂ unitingindividuals spiritually. Bunker＇s publications were translated into German. They corresponded to the Lebensreformmovement, but never became popular. Also the early sexology about 1900 ignored Bunker＇s concept as well as thesexual medicine later on. It is worthwhile to reconsider it within the context of the history of medicine, culture, andanthropology.

土木工程地质实践教学改革研究

根据大冶铁矿独特的地质教学资源和大冶铁矿实践教学基地的实际情况,对土木工程地质实习从内容、安排和质量保证等方面提出了实践教学方案的构想,探索了与企业生产相结合、与科研项目相结合、与学生能力培养相结合的实践教学改革新模式。

A STUDY ON RESPONSE OF PRECIPITATION IN CHINA TO MONSOON INTRASEASONAL OSCILLATION

Temporal and spatial evolution characteristics of the 30-60 day oscillation (intraseasonal oscillation, ISO) of summer rainfall in China and the effects of East Asian monsoon on the rainfall ISO are analyzed in this paper. Results show that the annual and decadal variations of the oscillation exist between 1960 and 2008, and the intensity is weakest in the late 1970s and early 1980s. In the typical strong years of the rainfall ISO obtained from empirical orthogonal functions (EOF mode 1), an anticyclone is in northwestern Pacific and a cyclone is in the east of China. In the typical weak years, the wind ISO is much weaker. The low-frequency zonal wind and water vapor transport from the low latitudes to mid-latitudes in the typical strong years, and the oscillation strength of diabatic heating is much stronger than that in the weak years of the rainfall ISO. The anomaly characteristics of the rainfall ISO show anti-phases between the Yangtze River basin and south of China. As for the typical strong years of the rainfall ISO in the Yangtze River basin (EOF mode 2), the main oscillation center of water vapor is in the east of China (20-30°N, 110-130°E). In the peak (break) phase of the rainfall oscillation, a low-frequency cyclone (anticyclone) is in the Yangtze River basin and an anticyclone (cyclone) is near Taiwan Island. In addition, the peak rainfall corresponds to the heat source in the Yangtze River basin and the heat sink in the Qinghai-Tibet Plateau. As for the typical strong years of the rainfall ISO in the south of China, the main oscillation center of water vapor is south of 20°N. In the peak (break) phase of the rainfall ISO, a low-frequency cyclone (anticyclone) is in the south of China and an anticyclone (cyclone) is in the Philippines. The peak rainfall corresponds to the heat source in the south of China and the South China Sea, and the heat sink in the west of Indochina.

Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.

Analysis of stable components for extended-range (10-30 days) weather forecast:A case study of continuous overcast-rainy process in early 2009 over the mid-lower reaches of the Yangtze River

A continuous overcast-rainy weather(CORW) process occurred over the mid-lower reaches of the Yangtze River(MLRYR) in China from February 14 to March 9 in 2009,with a large stretch and long duration that was rarely seen in historical records.Using the empirical orthogonal function(EOF),we analyzed the geopotential height anomaly field of the NCEP-DOE Reanalysis II in the same period,and defined the stable components of extended-range(10-30 days) weather forecast(ERWF).Furthermore,we defined anomalous and climatic stable components based on the variation characteristics of the variance contribution ratio of EOF components.The climatic stable components were able to explain the impact of climatically averaged information on the ERWF,and the anomalous stable components revealed the abnormal characteristics of the continuous overcast-rainy days.Our results show that the stable components,especially the anomalous stable components,can maintain the stability for a longer time(more than 10 days) and manifest as monthly scale low-frequency variation and ultra-long-wave activities.They also behave as ultra-long waves of planetary scale with a stable and vertically coherent structure,reflect the variation of general circulation in mid-high latitudes,display the cycle of the zonal circulation and the movement and adjustment of the ultra-long waves,and are closely linked to the surface CORW process.

China's English Education Reform:Trends and Issues

English education suffered a setback during the period of 1949-1976.The two decades between1977 and 1996 saw a period of restoration,growth and development.To welcome the arrival of thenew century,English education has moved on to the third stage:the period of reform.The paper argues for the need for English education reform,summarizes the work we have been doingsince 1997,lists the problems we have encountered,and gives some suggestions in the concluding remarks.

PROPAGATION OF 30—60 DAY LOW FREQUENCY OSCILLATIONS AND THEIR INFLUENCE UPON THE SUBTROPICAL WESTERLIES JET STREAM DURING NORTHERN HEMISPHERE WINTER

Based on daily ECMWF gridpoint data of two winters during 1981—1983 including an ENSO year,propagation of low frequency oscillations(LFO)during Northern Hemisphere winters and their influences upon 30—60 day oscillations of the subtropical jet stream are studied with the sta- tistical methods as complex empirical orthogonal function(CEOF)and so on.Results show that in the winter of a normal year(1981—1982),30—60 day oscillations in the subtropical zone are mainly in the northern and southern flanks of exit region of jet stream.In the ENSO year(1982— 1983),they are mainly in the vicinity of entrance and exit regions of jet stream.Intraseasonal changes of subtropical jet stream manifested themselves as latitudinal fluctuation or longitudinal progression or regression of about 40 day period.There are marked differences between propagat- ing passages of low frequency modes responsible for changes of subtropical jet stream in the normal year(1981—1982)and in the ENSO year(1982—1983).Changes of oscillation amplitude show obvious phases.In general,the one in late winter is stronger than that in early winter,strongest one occurs in February.

Investigation on the application of reformed coke oven gas in direct reduction iron production with a mathematical model

To investigate the application of reformed coke oven gas （COG） in producing the direct reduction iron （DRI）, we simulated a countercurrent gas solid moving bed reactor in which the iron ore pellet was reduced by reformed COG. An ordinary differential equation （ODE） was set based on the unreacted shrinking core model considering both mass and energy balances of the reactor. The concentration and temperature profiles of all species within the reactor were obtained by solving the ODE sys tem. The solid conversion and gas utilization were studied by changing gas flow rate, solid flow rate, reactor length, and the ratio of O/CHa to guide the practical application of COG in DRI production. Model results showed that COG was suitable for the DRI production. In order to meet the requirement of the industrial production, the minimum gas flow rate was set as 130,000 Nm3/h, and the maximum production was 90 t/h. The reactor length and the mole ratio x（O）： x（CH4） were depended on the actual industrial situations.

Shen Queying： A Reform Martyr＇s Widow or a Martyress of Her Own Causes？

The late Qing woman poet Shen queying （1877-19oo） had lived in the shadow of her husband, the reform martyr Lin Xu （1875-98）. This paper subverts the conventional portrayal of Shen queying as a chaste widow through reading her poems and song-lyrics in comparison with the poetic works of Lin Xu, to show that she herself was a reformer in her own right, and in this she was Lin Xu＇s vocal soul-mate rather than his mute wife and then widow. In her poems and song-lyrics, Shen Queying made clear that she had endeavored in poetic learning for expressing ＂the grand ambition of a racing steed,＂ and her poetry sent unmistakable message to become a political player herself in China＇s reform era, fighting for the welfare of the country and the people. For some subtle reasons, however, she was not able to fulfill this ambition by personally participating in the reform activities. Frustrated, she resolved to be a supporter and protector of her husband. Precisely because Shen queying had put so much of her reform ideal into her husband＇s career, the execution of Lin Xu fell on her as a double blow. Her pining away to death, although conforming to a seemingly late imperial lien^J model, transcends this traditional image and bears a clear mark of the reform era, when a woman tied her personal life closely to the destiny of the country and the people.