The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter ...The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter monsoon （EAWM）, this study finds that common indices of the EAWM cannot adequately describe the actual wind speed changes in the BTH region.Thus, observational data are used to analyze the interannual variations of the winter wind field over the BTH region. The results show that the average winter wind speed is 2.0 m s-1, with a slight rate of decline of 0.01 m s-1 yr-1. In most cases, strong-wind years correspond to negative sea surface temperature （SST） anomalies over the tropical Pacific, whereas weak-wind years correspond to positive SST anomalies. Moreover, correlation and composite analyses show that the interannual variability is affected by multiple factors, including the following： （1） the pressure gradient in the high and middle latitudes of the Northern Hemisphere, as in strong-wind years the pressure gradient helps cold air move from high latitudes to middle latitudes; （2） the skin temperature in Eurasia, as low skin temperature in Eurasia in strong-wind years is conducive to the accumulation of cold air; and （3） the SST of the tropical Pacific east of the Philippines, as in strong-wind years the high temperature of this area affects the BTH region through anticyclonic activity and associated tropical circulation systems.展开更多
The statistical character of QuikSCAT scatterometer winds is showed. And Monthly change and special distribution character of strong wind frequency and monthly wind fields in South China Sea is analyzed. It is shown i...The statistical character of QuikSCAT scatterometer winds is showed. And Monthly change and special distribution character of strong wind frequency and monthly wind fields in South China Sea is analyzed. It is shown in the result that the QuikSCAT scatterometer winds can be relied upon for the South China Sea; two winds, one the wintertime northeasterly and the other summertime southwesterly. The northeasterly centers at the Bashi Strait and Taiwam Strait and its secondary center and the maximum center of the southwesterly are in the central and southern South China Sea.展开更多
The authors investigate the characteristics of propagation and the influence on tropical precipitation of 9–29-day intraseasonal variation over midlatitude East Asia during boreal winter, and find that the intraseaso...The authors investigate the characteristics of propagation and the influence on tropical precipitation of 9–29-day intraseasonal variation over midlatitude East Asia during boreal winter, and find that the intraseasonal wind signal can propagate both eastward and southward. In the case of eastward propagation, the intraseasonal wind signal is mainly confined to the midlatitudes, featuring eastward migration of anomalous cyclones and anticyclones. In the case of southward propagation, intraseasonal meridional wind perturbations may extend from the mid to the low latitudes, and even the equatorial region. The accompanying wind convergence/divergence induces anomalous precipitation in the near-equatorial regions, forming a north–south dipole precipitation anomaly pattern between the southern South China Sea and the eastern China– Japan region. An anomalous meridional overturning circulation plays an important role in linking tropical and midlatitude intraseasonal wind and precipitation variations.展开更多
Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,tem...Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,temporal and spatial characteristics of moisture budgets over Asian and Australian monsoon regions are studied.The results show that there is apparent seasonal transition of moistrue sink and water vapor transport between Asian monsoon region and Australian monsoon region.In winter,the Asian monsoon region is a moisture source,in which three cross-equatorial water vapor transport channels in the 'continent bridge',at 80°E and 40°E～50° transport water vapor to the Australian monsoon region and southern Indian Ocean which are moistrue sinks.In summer,Australian Monsoon region anmd southern Indian Ocean are moistrue sources and by the three cross-equatorial transport channels water vapor is transport to the Asian monsoon region which is a moisture sink.In spring and autumn,ITCZ is the main moisture sink and there is no apparent water vapor transport between Asian monsoon region and Australian monsoon region.展开更多
This study explores the relationship between socioeconomics and millinery style through an analysis of statistical data from the United States Bureau of Statistics. It was very common for women to wear hats in the ear...This study explores the relationship between socioeconomics and millinery style through an analysis of statistical data from the United States Bureau of Statistics. It was very common for women to wear hats in the early 20th century. Most studies regarding millinery are limited to a discussion of style, while some focus on extended functions of millinery styles such as how they aid in social communication. In this study, we discuss the relationship between a woman＇s socioeconomic status and her hat-wearing behavior. This study covers the period from 1900 through the 1960s, when there was a sudden decline in hat-wearing behavior. We analyzed the changes in the number of people listed in various occupational categories in the U.S. Bureau of Statistics data for each decade. Careful observation of labor distribution statistics for the job market can yield valuable insights about women＇s hat-wearing behaviors. Fluctuations in the population of the lower class were significantly correlated with changes in millinery. We also identified time-sensitive periods in millinery style that coincided with the two World Wars.展开更多
This paper introduced the status quo of wind power and wind power generation technology. Focusing on the introduction of wind power generating system ibrational self-consistent field（VSCF）, program implementation in...This paper introduced the status quo of wind power and wind power generation technology. Focusing on the introduction of wind power generating system ibrational self-consistent field（VSCF）, program implementation included Alternating Current （AC）-Direct Current （DC）-AC conversion system, magnetic field modulation generator system, doubly-fed generator system etc. Among these, doubly-fed generator system is the trend. Where to build the wind farm is very important, so a perfect site is needed. Wind power generation will have a bright future. As long as the wind power can be linked to the grid in large scale.展开更多
Due to possible health effects of electric and magnetic fields, a directive on minimum health and safety requirements regarding the exposure of workers to electromagnetic fields has been disposed by European Parliamen...Due to possible health effects of electric and magnetic fields, a directive on minimum health and safety requirements regarding the exposure of workers to electromagnetic fields has been disposed by European Parliament and Council regarding the exposure of workers to electromagnetic fields. This legislation will be nationally implemented in 2012.The aim of this work was to develop a electromagnetic field exposure measurement method and further a magnetic field hazard evaluation method for exposure of workers in indoor medium to low voltage （MV/LV） distribution substations. Magnetic field exposure was also reflected with BS 8800 general risk classification procedure to accomplish specifications to execute magnetic field measurements and carry our risk assessment procedure for working tasks. The risk assessment procedure is based on magnetic field exposure measurements and dosimetric FEM calculations founded on EU Directive 2004/40/EC. According to field measurements action values were exceeded in several working tasks but limit values were not exceeded.展开更多
基金supported by the National Natural Science Foundation of China[grant number 41176014]
文摘The wind field plays a decisive role in haze generation and dissipation processes over the Beijing- Tianjin-Hebei （BTH） region. Although geographically the BTH region is under the influence of the East Asian winter monsoon （EAWM）, this study finds that common indices of the EAWM cannot adequately describe the actual wind speed changes in the BTH region.Thus, observational data are used to analyze the interannual variations of the winter wind field over the BTH region. The results show that the average winter wind speed is 2.0 m s-1, with a slight rate of decline of 0.01 m s-1 yr-1. In most cases, strong-wind years correspond to negative sea surface temperature （SST） anomalies over the tropical Pacific, whereas weak-wind years correspond to positive SST anomalies. Moreover, correlation and composite analyses show that the interannual variability is affected by multiple factors, including the following： （1） the pressure gradient in the high and middle latitudes of the Northern Hemisphere, as in strong-wind years the pressure gradient helps cold air move from high latitudes to middle latitudes; （2） the skin temperature in Eurasia, as low skin temperature in Eurasia in strong-wind years is conducive to the accumulation of cold air; and （3） the SST of the tropical Pacific east of the Philippines, as in strong-wind years the high temperature of this area affects the BTH region through anticyclonic activity and associated tropical circulation systems.
基金Key Scientific Project of Guangdong province Comprehensive application of satellite data in the monitoring and forecast of marine meteorology (99M05002G) Science and Technology Planning Project of Guangdong province Research on pre-warning techniques
文摘The statistical character of QuikSCAT scatterometer winds is showed. And Monthly change and special distribution character of strong wind frequency and monthly wind fields in South China Sea is analyzed. It is shown in the result that the QuikSCAT scatterometer winds can be relied upon for the South China Sea; two winds, one the wintertime northeasterly and the other summertime southwesterly. The northeasterly centers at the Bashi Strait and Taiwam Strait and its secondary center and the maximum center of the southwesterly are in the central and southern South China Sea.
基金supported by the National Natural Science Foundation of China [grant numbers 41530425,41721004,41475081,and 41775080]
文摘The authors investigate the characteristics of propagation and the influence on tropical precipitation of 9–29-day intraseasonal variation over midlatitude East Asia during boreal winter, and find that the intraseasonal wind signal can propagate both eastward and southward. In the case of eastward propagation, the intraseasonal wind signal is mainly confined to the midlatitudes, featuring eastward migration of anomalous cyclones and anticyclones. In the case of southward propagation, intraseasonal meridional wind perturbations may extend from the mid to the low latitudes, and even the equatorial region. The accompanying wind convergence/divergence induces anomalous precipitation in the near-equatorial regions, forming a north–south dipole precipitation anomaly pattern between the southern South China Sea and the eastern China– Japan region. An anomalous meridional overturning circulation plays an important role in linking tropical and midlatitude intraseasonal wind and precipitation variations.
基金Part One in Development Planning for National Key Fundamental Research (G1998040900)"South China Sea Monsoon Experiment Studies"caling Project A of National Ministry of Science and Technology
文摘Apparent moisture sink and water vapor transport flux are calculated by using NCAR/NCEP reanalyzed daily data for water vapor and wind fields at various levels from 1980 to 1989.With the aid of EOF analysis method,temporal and spatial characteristics of moisture budgets over Asian and Australian monsoon regions are studied.The results show that there is apparent seasonal transition of moistrue sink and water vapor transport between Asian monsoon region and Australian monsoon region.In winter,the Asian monsoon region is a moisture source,in which three cross-equatorial water vapor transport channels in the 'continent bridge',at 80°E and 40°E～50° transport water vapor to the Australian monsoon region and southern Indian Ocean which are moistrue sinks.In summer,Australian Monsoon region anmd southern Indian Ocean are moistrue sources and by the three cross-equatorial transport channels water vapor is transport to the Asian monsoon region which is a moisture sink.In spring and autumn,ITCZ is the main moisture sink and there is no apparent water vapor transport between Asian monsoon region and Australian monsoon region.
文摘This study explores the relationship between socioeconomics and millinery style through an analysis of statistical data from the United States Bureau of Statistics. It was very common for women to wear hats in the early 20th century. Most studies regarding millinery are limited to a discussion of style, while some focus on extended functions of millinery styles such as how they aid in social communication. In this study, we discuss the relationship between a woman＇s socioeconomic status and her hat-wearing behavior. This study covers the period from 1900 through the 1960s, when there was a sudden decline in hat-wearing behavior. We analyzed the changes in the number of people listed in various occupational categories in the U.S. Bureau of Statistics data for each decade. Careful observation of labor distribution statistics for the job market can yield valuable insights about women＇s hat-wearing behaviors. Fluctuations in the population of the lower class were significantly correlated with changes in millinery. We also identified time-sensitive periods in millinery style that coincided with the two World Wars.
文摘This paper introduced the status quo of wind power and wind power generation technology. Focusing on the introduction of wind power generating system ibrational self-consistent field（VSCF）, program implementation included Alternating Current （AC）-Direct Current （DC）-AC conversion system, magnetic field modulation generator system, doubly-fed generator system etc. Among these, doubly-fed generator system is the trend. Where to build the wind farm is very important, so a perfect site is needed. Wind power generation will have a bright future. As long as the wind power can be linked to the grid in large scale.
文摘Due to possible health effects of electric and magnetic fields, a directive on minimum health and safety requirements regarding the exposure of workers to electromagnetic fields has been disposed by European Parliament and Council regarding the exposure of workers to electromagnetic fields. This legislation will be nationally implemented in 2012.The aim of this work was to develop a electromagnetic field exposure measurement method and further a magnetic field hazard evaluation method for exposure of workers in indoor medium to low voltage （MV/LV） distribution substations. Magnetic field exposure was also reflected with BS 8800 general risk classification procedure to accomplish specifications to execute magnetic field measurements and carry our risk assessment procedure for working tasks. The risk assessment procedure is based on magnetic field exposure measurements and dosimetric FEM calculations founded on EU Directive 2004/40/EC. According to field measurements action values were exceeded in several working tasks but limit values were not exceeded.
