Vol.17, NO.6, 2006

Display Method:
Progress on Cryospheric Studies by International and Chinese Communities and Perspectives
Qin Dahe, Xiao Cunde, Ding Yongjian, Yao Tandong, Bian Lingen, Ren Jiawen, Wang Ninglian, Liu Shiyin, Zhao Lin
2006, 17(6): 649-656.
The recent program of WCRP/CliC, which represents the current tendency of the international studies on cryopshere, is introduced. Cryopshere is an important water resource in China for maintaining the socioeconomic development in the arid and oasis regions, it also plays an important role in stabilizing the ecological system over the cold regions of western China such as Qinghai-Xizang Plateau. With the global warming, the effects of the climate, environment, ecology and water resource by cryospheric decay are becoming more negative and stronger. These effects threat the security of the sustainable development in western China. It suggests that future cryospheric studies in China should focus on the following 5 projects: Processes monitoring, paleo-climate and paleo-environment records, cryospheric and climatic modeling, relations of cryospheric change and water resources, and impacts assessment and adaptation strategy under various scenarios of cryospheric changes.
The Atmospheric Science Development Situation in China and the Analysis on the Priority Areas
Xu Xiaofeng, Hu Xin, Wang Weidan, Zhang Zheng, Zhang Hongguang, Wang Xuechen, Li Changxing, Li Hongchen
2006, 17(6): 657-664.
Based on the survey of the domestic organizations in atmospheric science and the related areas, an overview of China atmospheric science development situation is made, with the emphases on human resources, scientific research projects and science papers. The study shows that since 1990s the atmospheric science in China has continually developed and the merging of the atmospheric science and other disciplines has enhanced. The total number of personnel is big and the employees are broadly distributed. But the high level talented persons are obviously insufficient. A comparison study on atmospheric science development situation, national and international research hot topics and the domestic demand is also made with the bibliometric analysis. Four judgment criteria are put forward and the priority areas in atmospheric science are investigated from four different aspects. The preliminary study indicates that whether the basic research or the applied research is emphasized, the weather modification and the atmospheric physics should be the priority areas. When scientific hot topics and the scientific frontiers are focused, climate system and global change, weather dynamics and weather forecast are the priority domains. Synthesized sounding system, field experiment and atmospheric chemistry are the priority areas when development demand and the scientific frontiers are stressed.
Researches on Meso-scale Meteorology in Chinese Academy of Meteorological Sciences
Zhou Xiuji
2006, 17(6): 665-671.
Meso-scale meteorology has been the primary research area of Chinese Academy of Meteorological Sciences for the recent 50 years. As early as in 1963, Chinese Academy of Meteorological Sciences is already a dominant participator of the first Yangtze Area Delta Meso-scale Meteorology Field Experiment. Since then, a series of grand science research programs are directed, among which are Monitoring and Ultra-short Term Predicting of Disaster Weather in Beijing, Tianjin and Hebei District during 1986—1990, Torrential Rainfall Experiment over Both Side of the Taiwan Strait and Adjacent Area (HUAMEX) during 1997—2003, Research on Formation Mechanism and Prediction Theory of Severe Weather Disasters in China during 1998—2003, Research on Theories and Methods of Monitoring and Predicting of Heavy Rainfall in South China during 2004—2009. In these programs, Chinese Academy of Meteorological Sciences successfully develops lots of innovative instruments, e.g., digital weather radar systems, Doppler weather radar systems, mounted Doppler weather radar systems, wind profiles radar systems, double channel auto-scanning microwave radiometers, automatic weather station network and an effective integrated system of meso-scale meteorological data collecting, processing, analyzing and displaying. A nonhydrostatic multi-scale atmospherical numerical forecasting model has also been developed. With the implementation of modern meso-scale observation network, Chinese Academy of Meteorological Sciences starts several meso-scale storms observation experiments, and obtains plentiful data. Very important scientific and technological support to research of meso-scale meteorology in China have been provided by these approaches. Thanks to these contributions, Chinese Academy of Meteorological Sciences has received 16 National Awards of Scientific and Technological Progress.
The Evolution on Research and Operational Forecasting Techniques of Tropical Cyclones
Chen Lianshou
2006, 17(6): 672-681.
Heavy rainfall, storm surges and strong winds brought about by tropical cyclones are an acute natural disaster which will result in severe damages of loss of lives and properties. Accurate forecasts and warnings on tropical cyclone activities are one of the major responsibilities for tropical cyclone forecasters and researchers.Tropical cyclone has been studied systematically in China in this half century including various topics of tropical cyclone motion and its forecasting techniques, formation and extratropical transition, structure and intensity change, tropical cyclone landfalling and abrupt change in this stage, sustaining and decaying over land, rain/wind distribution etc. The research achievements from Chinese Academy of Meteorological Sciences (CAMS) in this half century are reviewed for her 50-year anniversary. Other research works related to CAMS could be raised but it is not a comprehensive summary at all.The research methodology and technical strategy with CAMS are advanced in different era. Mathematical-physical statistics, mechanism analysis with synoptic-dynamical theory, numerical simulation, physical diagnostics and field experiment programs etc. are employed in the research programs and play an critical role to advance the tropical cyclone researches in the nation.Another characteristic of the research in CAMS is to integrate the theory with practice, to integrate the research with operational needs, to transfer the research achievements to operational forecast. One of the scientific objectives for CAMS is to raise the operational capacity of tropical cyclone forecasting.Several decades ago, scientists treated tropical cyclone as a particle without volume because people don't know much about the detail structure of it due to lack of data in the vicinity of storms. Motion forecast depends on the environmental steering derived from one layer barotropic model. Now motion forecast can be done by the high resolution global spectral model with data assimilation and bogussing tropical cyclone in CAMS. This technical variation cost 50 years or so. This also reflects the progress and advances of remotely sensed techniques and computer capacity in this time span.A serial field programs carried out by CAMS in the past 2 decades are helpful for the research programs on the sudden change in motion, intensity and rainfall of coastal typhoons and landfalling tropical cyclone studies. Relevant research achievements would be transferred to operational communities.Scientific cooperation and coordination especially the international cooperation are needed for the tropical cyclone research in CAMS. The technical cooperation between CAMS and operational centers are more important and beneficial for both sides. Some of the achievements are the common results of the cooperation, which should be explored and developed in the future research programs.
An Overview on Radar Meteorology Research in Chinese Academy of Meteorological Sciences for a Half Century
Liu Liping, Ge Runsheng
2006, 17(6): 682-689.
Significant progresses in the radar meteorology and meteorology radar have been made by the scientists and technicians in Chinese Academy of Meteorological Sciences in the past half century. The early history and recent development of radar research work in Chinese Academy of Meteorological Sciences are reviewed. The main topics are as following: The technology and applications of analogy weather radar, digital weather radar, Doppler radar, dual linear polarization radar, bistatic radar; the application of these radars on watching, warning and nowcasting of hail, heavy rain fall, typhoon; recent research work on field experiment for heavy rain fall and typhoon, the 3-D mesoscale wind structures of heavy rainfall, squall line by dual Doppler radar and bistatic radar network technique; the microphysical structures retrieval by dual linear polarization radar, 3-D mosaic and nowcasting with CINRAD. The radar research work in recent years in the National Laboratory of Severe Weather are focused on Doppler Lidar, millimeter radar, movable and airbone radar technologies and their applications. The dropsounding system is also developed and used in heavy rainfall and typhoon systems observation and forecast.
Experiments and Studies for Heavy Rainfall in Southern China
Ni Yunqi, Zhou Xiuji, Zhang Renhe, Wang Pengyun, Yi Qingju
2006, 17(6): 690-704.
In the last 50 years, several generation scientists of CAMS devote to the study of heavy rainfall in China. A great achievement in the heavy rainfall studies are made. Especially in the recent 10 years, three big research programs of the state class are implemented or are being implemented in Chinese Academy of Meteorological Sciences, which focus on heavy rainfall of Southern China, including experiments and studies of heavy rainfall in Southern China and within Meiyu front in the mid-lower reaches of the Yangtze River, and heavy rainfall causing flood in South China with the study scope more comprehensive than the above two programs.Through the implementation of the above programs, three dimensional structure and formation mechanisms of the heavy rainfall in southern China and within Meiyu front in the mid-lower reaches of the Yangtze River, as well as the theories and the methods of remote sensing detection and measurement of the meso-scale heavy rainfall and the development of the meso-scale heavy rainfall numerical prediction systems with 3Dvars are all made several important achievements. Some of them are applied into operation in the operational divisions within different levels of China Meteorological Administration. As a result, economic and social benefits contribute from them in China. In the implementing of the 973 state program, the research focuses on the study and experiment for heavy rainfall systems with meso-β scale. Though these studies and experiments, wish is made that it is possible to enhance the capability of detecting and forecasting heavy rainfall in South China, and also it is hoped that important contribution could be made to strengthen the capability of reducing and protecting the disasters in China.
Climate Observing System and Related Crucial Issues
Zhang Renhe
2006, 17(6): 705-710.
The climate system is composed of five spheres in the earth system, i.e., atmosphere, hydrosphere, cryosphere, lithosphere and biosphere. The interaction among these spheres of climate system determines the natural climate variability. As the human activities increase, more and more influence has exerted on the climate system. Both natural and anthropogenic climate changes have influenced greatly on the society, the economics and the human life, and have led to the arousing of the issues on the national security, the environmental diplomacy and the sustainable development, etc. In order to understand the climate change and its forcings, and forecast the future climate change, the basic need is to set up a comprehensive climate observing system dealing with the five spheres in the earth system. The detailed information on the variation of the climate system can be provided by the high quality climate data and related products obtained from the climate observing system. The development of designing a climate observing system in China is reviewed, especially the role played by the Chinese Academy of Meteorological Sciences. Based on the analysis of the climate observing system, some crucial issues concerning the setting up of the climate observing system are discussed. These issues include the scientific requirements to the climate observing system, its representativeness, comprehensiveness, standard, supportiveness to the climate prediction and projection and to the climate model development, application to the interdisciplinary, social and economical application, data opening and sharing, assimilation and reanalysis of the climate system data, and the rescue of the historical data.
Progress in Research on the East Asian Monsoon
Chen Longxun, Zhang Bo, Zhang Ying
2006, 17(6): 711-724.
Chinese Academy of Meteorological Sciences (CAMS) has organized the investigation on the East Asian Monsoon with its influences on the weather and drought/flood in China for a long term since the foundation of new China. A summary of the achievements of the past researches by CAMS is briefly depicted. A basic review of the East Asian Monsoon researches in China after 1950s; the study on the East Asian Monsoon circulation system (EAMCS): the history of proposals to EAMCS affecting the weather and climate in China, the interactions between East Asian and Indian Monsoon system, the water vapour transportation resulting in the torrential rain in China, and the design of the monsoon index representing the East Asian Monsonn activity are set forth. The seasonal variation of EAMCS is summarized on the onset of the South China Sea Summer Monsoon, Meiyu and the rainy season in China and its propagation. The Madden-Julian oscillation (MJO) of EAMCS and its impacts on the summer precipitation in China are presented by the study on the characteristics of zonal and meridional propagation of the subtropical MJO of EAMCS, the differences between it and that on the Equatorial area, and its possible effects on the formation of El Niño, the onset of East Asian tropical and subtropical monsoon and the weather and climate in China. The calculation and distribution of atmosphere apparent heat source in Asia, and its possible influence on the East Asian Summer Monsoon and the rainfall, and the possible influence of the winter cold source over the Tibetan Plateau on the formation of El Niño are given. The inter-annual and interdecadal variation of the EAMCS are reviewed on the characteristics of the inter-annual variation of the EAMCS and the rainfall, the analysis of the quasi-4-year oscillation, the interaction between it and the formation of El Niño, the impact of the polar region on the summer rainfall in East Asia, and the inter-decadal variation of the EAMCS. The possible mechanism of the formation of the EAMCS is proposed, especially the essential role in the formation of summer and winter monsoon, the EAMCS and the Indian Monsson system of the land-sea thermal difference between the Asian continent and the West Pacific, the African continent, the Indian and IndoChina peninsula, Australian continent, and the ocean and sea around them.
Some Advances in Climate and Climate Change Research
Zhao Ping, Nan Sulan
2006, 17(6): 725-735.
Some advances in Chinese Academy of Meteorological Sciences in climate and climate change research are reported, which include the recovery, reconstruction and processing of historical documents, the climatic zoning division, the variations of air temperature and precipitation in China, the features of air temperature and precipitation, the land-atmosphere process on the ground layer and the boundary layer, the heat source/sink and the ozone in the Tibetan Plateau, the simulation on paleoclimate, the theories and methods of predicting the climate change and the influence of the climate change on the society and the economy. In the recent 50 years, a lot of climate data are selected and "Precipitation Distribution Maps in China in recent 500 Years" is published. Wind energy resource zone is defined. It is confirmed that there are two warm periods in 1940s and 1990s and a relative cool period during 1950s—1960s. Under the context of global warming, the southwest region centered in Sichuan Province cools from 1950s until 1980s in China; the rainy zone shifts from North China to the middle and lower reaches of the Yangtze River. The synthetical physical image is indicated. The low value center of summer ozone in the Tibetan Plateau is found. The climate change features is simulated during the Tibetan Plateau apophysis. The monsoon circulation system in East Asia and its members are revealed. Many prediction methods are designed. The research achievements are also transferred to the economic development.
Progresses on Climatological Statistical Diagnosis and Prediction Methods———In Commemoration of the 50 Anniversaries of CAMS Establishment
Wei Fengying
2006, 17(6): 736-742.
An overview of the progress in Chinese Academy of Meteorological Sciences (CAMS) has been made on the method of climatological statistical diagnosis and prediction in recent 50 years. The study on climatological statistical diagnosis and prediction falls into such several phases as the introduction, the application, the outspreading and the innovation. In 1960s, statistics methods and application into studies on climatological statistical analysis and prediction, incorporating the climatic characters in China are introduce by the climatologists. In this period the introduction, application and outspreading of the statistics are explored and great effective studies are made on by researchers in CAMS. During 1970s and 1980s, great effort has been made and fuzzy set theory and gray system to every branch of atmosphere science. In 1990s, studies on climatological statistical diagnosis and prediction are very active. Employing new methods and new technology widens the field of vision on understanding and forecasting the climate system; and many observation facts are obtained. During this period, the relative studies in CAMS are plentiful, not only the climatic trend, diagnosis of climate abrupt, interdecadal oscillation and interaction of different scales variability, but also the causes of climate anomaly. In order to improve the level of short-term climate forecast further, a series of new methods of statistical forecast are proposed and developed which play important roles in climate operational prediction and weather decision-making.
A Study on Polar Atmospheric Sciences and Global Change
Lu Longhua, Bian Lingen, Xiao Cunde, Wu Bingyi, Lu Changgui
2006, 17(6): 743-755.
The Antarctic and the Arctic are not only the sensitive areas to global climate changes, but also key areas focused by many international scientific projects. The polar atmospheric scientific expedition and investigation are important branches of the polar scientific research. The project, launched by Chinese Academy of Meteorological Sciences (CAMS), starting in the 1980s, has made great progress during the past 25 years. CAMS joins totally 23 times Antarctic, as well as 2 times Arctic Ocean, and 3 times Arctic station expeditions. All of these expeditions are organized by China government. CAMS has provided supports for meteorological observations in China Antarctic Great Wall Station, China Antarctic Zhongshan station, and China Arctic Huanghe Station, as well as building for three automatic weather stations on the Antarctic ice sheet belonging to a China-Australia cooperation project. A series of measurements and observations, including meteorological elements, atmospheric ozone, surface layer physics, snow and ice, atmospheric chemistry observations etc, have been accomplished by CAMS, obtaining a batch of fairly systematic original data on polar atmosphere and environment. CAMS investigates the polar atmospheric science and global changes, and makes great progress in the following fields: "the polar weather and climate characters and the spatial-temporal variety of climate change", "the polar sea-ice variation and Antarctic oscillation", "the polar surface layer characters and sea-ice-air interactions", "ozone variability of China Antarctic Zhongshan station, Antarctic ozone hole and atmospheric chemistry", "data retrieval of climate proxies and paleo-climate and environment", and "the effects of the polar atmospheric environment variation on East Asian circulation, China weather and climate". In the Antarctic and the Arctic, CAMS is strengthening the cooperation with international institutions, continuing to monitor the meteorological elements, improving the service standard of the polar meteorology, expanding the studying fields of the polar meteorological services and atmospheric scientific research, promoting data retrieval of climatic proxies, quantifying and understanding the role of polar regions in global changes and its influences on China weather and climate, and the domestic economic sustainability. To set up and complete the polar atmospheric scientific research system, and improve the study level is essential for the polar atmospheric scientific research and global changes in CAMS.
Advances of the Study on Tibetan Plateau Experiment of Atmospheric Sciences
Xu Xiangde, Chen Lianshou
2006, 17(6): 756-772.
A review of the research work on Tibetan Plateau for the recent 50 years is given. Especially, the important results for the first atmospheric science experiment on Tibetan Plateau in 1979 (QXPMEX) and the second one in 1998 (TIPEX) are suggested.It is found the long-frenquency oscillation which is inherent in Tibet Plateau tropospheric circulation and marked by out-ward propagation and the characteristics of Ekman spiral of PBL can be seen over Tibetan Plateau. The height of PBL is found to be as high as 2200 m over Tibetan Plateau, it is much higher than those in the plain areas. Dynamic and thermodynamic structures, as well as the characteristics of turbulence and convective clouds in the Plateau are discussed. A comprehensive physical pattern of convective structure of PBL is also given. It is found that under the condition of proper cloud cover, extremely high values of global solar radiation, effective radiation and surface net radiation are measured and the rain storm and flooding associated with the initial convective cloud system can be tracked to the Tibetan Plateau area. The regional impacts of heat source and heat sink associated with changes of the surface albedo over Tibetan Plateau are discussed. And the seasonal scale change of mid-long wave in the atmosphere is under the influence of the regional and seasonal change that is brought by the heat source and sink. The feedback of annual scale change of snow cover on the Tibetan Plateau is also emphasized in the research result, it shows that the planetary scale circulation on the Tibetan Plateau, the anomaly of SST and their interactions can be influenced by the snow cover. There are remarkable evolutions of the interactions of Tibetan Plateau and Asian monsoon. It is found that the availability of sensitive heat pump (SHAP) induces the abrupt air circulation from winter to summer and the South Asian High jump to the north, and maintains the period of the monsoon. It is found that Tibetan Plateau and its eastern areas "large triangle" are key areas for the transportation of water vapor flow. It is a very important rule to form the rain storm and the flooding in the Yangtze River during Meiyu period. The characteristics of matter transfer and ozone anomaly on Tibetan Plateau are found. There is a low value center of ozone on Tibetan Plateau in summer and the descending trend of ozone in Lhasa is notable than that of the east of China at the same latitude. Lhasa locates in the areas of ozone low value center.
Recent Progress on GRAPES Research and Application
Chen Dehui, Shen Xueshun
2006, 17(6): 773-777.
Since 2000, in the support of two national key projects of "Chinese Heavy Rain Research Experiment" and "Research on Meteorological Numerical Prediction System Techniques", LaSW/CAMS has been in charge of developing new generation NWP system GRAPES (Global/Regional Assimilation and PrEdiction System). GRAPES' project is mainly focused on data assimilation, dynamical core, physical parameterization schemes, and infrastructure software. The main achievements include 3 dimensional variational data assimilation; standardized, modularized and parallelized coding infrastructure; full-compressible and non-hydrostatic meso-scale NWP system and its various applications. The operational results are highly encouraging and promoting for further developments. Also, a brief introduction to GRAPES research project, main progresses and some applications with future plan of GRAPES development is given.
Advances of Agro-meteorological Research in CAMS During Recent 50 Years
Wang Futang
2006, 17(6): 778-785.
Agro-meteorology is mainly focused on the interactions of meteorological conditions with ecology and agricultural production and their mechanisms. The history of about 100 years indicates that the development of agrometeorology is closely linked with the development of the national economy and the agricultural production. Particularly, since the end of 1970s, agro-meteorology in CAMS develops quickly and vigorously, and great achievements are gained. Some major issues of agro-meteorological research in CAMS during recent 50 years is described on the basis of a brief review of its historical development in China in last century.Based on the agro-climatic resources inventory and analyses on its geographic distribution, the national agroclimatic zoning has been completed using an agro-climatic index system and the classified zoning method. Some years later, the conceptions of the stereoscopic gradation and its agro-ecological exploitation are presented in studies on the mountain agro-climatic resources rational utilization in the subtropical and tropical areas in China. Agro-meteorological simulation and prediction models for major crops' yield in China have been developed and applied successfully in meteorological operation departments. Then, a national integrated estimation system of winter wheat yield by remote sensing of meteorological satellite is established and put into operation. All of these not only fill the gaps in agro-meteorology, but also develop the new methods of crop yield prediction, as well as contributed to provide a new way of meteorological services for agriculture. In the research on "Crop Water Stress and Drought in the North China Plain" a meteorological dryness model and the crop drought prediction methods are developed as well as an optimization for irrigation schedules is formulated and applied widely in North China. During the recent 10 years the new prediction methods, impact disk assessment and prevention techniques for the major agro-meteorological disasters in China have been achieved. Linking the climate-ecology models with the climate change scenario in the future, projected from 7 GCMs, a simulation at a resolution of 0.5°×0.5° is conducted, which indicates that the present distribution of characteristic vegetation and cropping system in China will change greatly due to the climate warming. An open-top chamber experiment shows that the fertilization effect induced by increasing CO2 will be favourable to crops. However, climate warming is not bound to cause the rising of the precipitation. As a result, favourable and unfavourable impacts would offset each other and lead to the reduction of crop output. Apart from both assessment models of climate abnormality, the impacts on double cropping rice production south to the Yangtze River and maize production in Northeast China with potential use in operation have also been developed. Based on the more than 10-year field experiments and computer growth simulation, a series of models for simulating the growth of wheat, rice (including double cropping rice) and maize have been established successfully. In the study on operation application, the above simulation models have been nested both into the regional climate models and the satellite dynamical monitoring by remote sensing. And a new type of forewarning model and method for agro-meteorological disasters is completed. Based on the establishment of a set of information analyzing and assessing indexes, agro-meteorological disaster indexes as well as the crop yield prediction models, the state-level operational agro-meteorological information service and crop output forecasting systems are exploited and developed. At present, the systems are able to provide a variety of analyzed information products and consultation service for the relevant government departments and the media. Great social and economical benefits are produced.
Review of Weather Modification Research in Chinese Academy of Meteorological Sciences
Yao Zhanyu
2006, 17(6): 786-795.
In the past more than 40 years, weather modification researches in Chinese Academy of Meteorological Sciences focus on precipitation enhancement techniques and field experiment, hail cloud physics and hail suppression; fog structure observation and fog dispersion, cloud macrostructure and cloud atlas, cloud and precipitation model and numerical simulation, laboratory study on cloud physics and cloud seeding agents, tools and techniques etc. Plentiful research productions are made, many of which are widely used in weather modification operation and practice in China and have resulted in practical benefits.
Review of Atmospheric Chemistry and Environment Research Work in Recent 30 Years———In Commemoration of the 50 Anniversaries of CAMS Establishment
Ding Guoan, Zheng Xiangdong, Ma Jianzhong, Liu Yu, Yan Peng
2006, 17(6): 796-814.
Research work associated with the atmospheric chemistry and environment undertaken in the CAMS in recent 30 years is reviewed. The work is mainly supported by the key projects from the National Natural Science Foundation and by the "973" project from the Ministry of Science and Technology of China. The main significantly creative achievements are as follows: The first discovery of the summer total ozone valley occurring over the Tibetan Plateau; with the consideration of the environment, ecosystem, climate as an integrated system, impacts from anthropogenic activities on the environment through changing the status of the ecosystem, and its influencing on the regional climate is better identified in China; understanding of the mechanisms of the atmospheric pollution in Beijing city and the methods of modulation of the pollution are much improved. The achievements of solving the critical difficulties of the atmospheric environmental problems in Beijing are creatively approached based on the 3-dimension observations, with the integrated analysis of statistics and dynamics, the surface and satellite observations, and the model simulations; the first continent Global Atmospheric Watch (GAW) baseline observatory is established at Mt Waliguan, Qinghai Province, initialing the GAW routine observations in China. In conclusion, the work of 30 years in CAMS contains almost all the important topics of the atmospheric chemistry and their frontier researching contexts. These topics are listed as greenhouse gases, total ozone, reactive gases, aerosols, acid rains, the development and applications of atmospheric chemistry model simulations, the forecast methods of air quality and the assessment of atmospheric environment etc. The advances of atmospheric chemistry in CAMS are much related to the constructions of monitoring network operated by the CMA. The establishments of monitoring networks of GAW, acid rain, total ozone, dust storm have provided CAMS with a common platform for atmospheric chemistry researches.
Beijing City Air Pollution Observation Experiment
Xu Xiangde, Ding Guoan, Bian Lingen
2006, 17(6): 815-828.
The atmospheric part of key project from the National Fundamental Research Planning is introduced, i.e., "Air, Water and Soil Environmental Pollution Mechanism and Its Regulating-Controlling Principles in Beijing and Its Ambient Area". Beijing City Air Pollution Observation Experiment (BECAPEX) is the most comprehensive field program carried out to date to characterize the air pollution sources and processes in and around Beijing City during the period from 2001 to 2003. A key issue of the BECAPEX experiment addresses is whether the air quality in the Beijing Metropolitan area (BMA) can meet the standards in 2008 set by the Beijing Olympic Organizing Committee by controlling the emissions within BMA. Observations from BECAPEX reveals that the air quality in BMA is a regional problem. Although the reduction of emissions within BMA can generally improve its air quality, under certain weather conditions, the transports by local heat island circulation, synoptic and large-scale winds can carry pollutants from neighboring regions to the south and east of the BMA. These multi-scale transports play a crucial role in determining the air quality in the BMA. Thus, in order to properly address its air pollution issue, Beijing and its neighboring regions must be considered as an integrated system, where pollution control strategies must be formulated synergistically. Results show that there exists significant difference in the contribution of winter/summer different pollution emission sources to the component character of atmospheric pollution. Surface layer atmospheric dynamic and thermal structures and various pollutant species at the upper boundary of buildings ensembling at urban different observational sites of Beijing in winter and summer show an "in-phase" variation and the spatial scale feature of "influence domain". The power spectrum analysis (PSA) shows that the period spectrum of winter/summer particle concentration accords with those of atmospheric wind field. It is found that from analyzing the urban area thermal heterogeneity, the multi-scale effect of Beijing region urban heat island (UHI) is associated with the heterogeneous expansion of the tall buildings area. In the urban atmospheric dynamical and thermal characteristic spatial structures, the turbulent scale feature of the urban boundary layer (UBL) of architectural complexes has an important impact on the multi-scale feature of the urban atmospheric pollution. The comprehensive analyses of the variational analysis field of Moderate Resolution Imaging Spectroradiometer (MODIS) AOD-surface PM10 under the condition of clear sky and the correlation resultant wind vector field for pollution sourcetracing suggest that the emission sources for winter Beijing atmospheric pollution aerosols particle might be remotely traced to the south peripheral greater-scale spatial range of Hebei, Shandong, and Tianjin etc. The backward trajectory feature of winter/summer air particles exhibits analogous multi-scale feature, and depicts the difference in the scale feature of the pollution sources spatial distribution in different season. The peripheral source trajectory paths of urban atmospheric pollution (UAP) mainly come from the fixed industrial surface source or heating surface source in the outskirt of Beijing. The high value area of the winter Total Ozone Mapping Spectrometer (TOMS) AOD lays in the Beijing region and its south peripheral area, an S-N zonal pattern, which reflects the dynamical effect of peripheral topographic pattern on the diffusion of regional scale atmospheric pollution sources. Study suggests that the extent of winter atmospheric pollution within the "valley" megarelief in Beijing and its periphery is closely related to the pollution emission sources of the south peripheral area; and the significant "anti-phase" variation feature of the winter AOD and sunshine duration in Beijing and its peripheral areas, and the regional scale correlation of low cloud cover, fog days, and aerosols reflect the local climatic effect of aerosol influence in this region. Based on the analysis of the air pollution observational data, several models developed by members of this program are revealed.
Review and Progress of Lightning Research
Zhang Yijun, Zhou Xiuji
2006, 17(6): 829-834.
The recent lightning research progresses are summarized in the following areas as the lightning locating technology, spatial-temporal characteristics of lightning activity in Beijing area, relationships between lightning activity and strong convective weather, lightning forecasting and warning method, lightning physical processes, numerical simulation of thundercloud electrification and lightning discharges. Through the researches in these aspects, the lightning discharge characteristics are acquired systemically, especially in the spatial-temporal characteristics in Beijing area. Furthermore, important advances in lightning forecasting and warning method and lightning physics process are also obtained. However, the observation experiment and theoretical research of lightning discharge processes still need to be improved because of the randomicity and transience of lightning occurrence. In order to comprehend the lightning physics thoroughly, long-term basic researches on the dynamics, the microphysics and the electrification activity in the thunderstorm and their relationship are also needed. The theoretical foundation for lightning forecasting and warning will be provided by these researches, and the application of lightning locating information will be improved for the detection and warning of strong convective weather. On the basis of the further study of lightning initiation and propagation, the research of lightning damage mechanism will be carried out, e.g., the attachment process of CG lightning, the damage to electronic instruments caused by different electromagnetic radiation frequency range etc, by which the technical support for lightning protection can be provided.