为全面、即时搜集分散于互联网上游离的气象数据,满足各行业、各领域、各学科科研部门的数据需求,提出使用Google MEAN Stack全栈技术开发基于Cheer IO的高效定向爬虫,充分利用Node.js高性能I/O的特性,实现气象信息的快速搜集。同时将...为全面、即时搜集分散于互联网上游离的气象数据,满足各行业、各领域、各学科科研部门的数据需求,提出使用Google MEAN Stack全栈技术开发基于Cheer IO的高效定向爬虫,充分利用Node.js高性能I/O的特性,实现气象信息的快速搜集。同时将技术栈与地理信息系统技术、数据可视化技术以及云计算技术相结合,通过地理信息系统的数据存储、查询、自动制图、统计分析等功能对信息进行分析和处理,在阿里云平台上构建了一个能抓取并存储海量数据、提供实时气象数据的应用系统,提供便捷的检索、查询功能,有较强的实用性。本文结合气象数据爬虫的解决方案,对MEAN Stack数据爬虫的开发框架、项目架构以及爬虫核心技术(抓取目标策略、网页分析算法、多线程并发运算等)进行了深入分析研究与实现。展开更多
In this paper we summarize the characteristics of the dishpan experiment, the principle of substance revolving, and the scientific basis of the “retrograde wave in only one direction” with respect to weather data an...In this paper we summarize the characteristics of the dishpan experiment, the principle of substance revolving, and the scientific basis of the “retrograde wave in only one direction” with respect to weather data and S. C. OuYang＇s articles in which the fundamental questions in the meteorological theory were pointed out. Furthermore, we discuss the systematic changes involving the concept, theory, and method that substance evolves.展开更多
This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for ...This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for Medium-Range Weather Forecasts, Japan Meteorological Agency and National Centers for Environmental Prediction in the THORPEX Interactive Grand Global Ensemble(TIGGE) datasets. The multi-model ensemble schemes, namely the bias-removed ensemble mean(BREM) and superensemble(SUP), are compared with the ensemble mean(EMN) and single-model forecasts. Moreover, a new model bias estimation scheme is investigated and applied to the BREM and SUP schemes. The results showed that, compared with single-model forecasts and EMN, the multi-model ensembles of the BREM and SUP schemes can have smaller errors in most cases. However, there were also circumstances where BREM was less skillful than EMN, indicating that using a time-averaged error as model bias is not optimal. A new model bias estimation scheme of the biweight mean is introduced. Through minimizing the negative influence of singular errors, this scheme can obtain a more accurate model bias estimation and improve the BREM forecast skill. The application of the biweight mean in the bias calculation of SUP also resulted in improved skill. The results indicate that the modification of multi-model ensemble schemes through this bias estimation method is feasible.展开更多
With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becom...With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becomes necessary to investigate the effects of the radiation and air pressure on insulation materials. This paper describes the effects of gamma-ray irradiation and reduced pressure on dielectric breakdown of polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) by applying a DC pulse voltage. Both PBN and PBT were irradiated in air up to 100 kGy and then up to 1 000 kGy with a dose rate of 10 kGy/h by using a60Co gamma-source. The effects of total dose and reduced pressure on the time to dielectric breakdown and discharge quantity were discussed. Obtained results show that, while increasing the total dose, the discharge quantity decreased with PBN, but increased with PBT. With decreasing the air pressure, the discharge quantity increased with PBN, but decreased with PBT. With increasing the total dose, the time to dielectric breakdown increased with PBN, but decreased with PBT. With decreasing the air pressure, the time to dielectric breakdown increased with both PBN and PBT. The experimental results suggest that the chemical structure of polybutylene polymers plays a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction.展开更多
A hybrid GSI （Grid-point Statistical Interpolation）-ETKF （Ensemble Transform Kalman Filter） data assimila- tion system has been recently developed for the WRF （Weather Research and Forecasting） model and tested ...A hybrid GSI （Grid-point Statistical Interpolation）-ETKF （Ensemble Transform Kalman Filter） data assimila- tion system has been recently developed for the WRF （Weather Research and Forecasting） model and tested with simu- lated observations for tropical cyclone （TC） forecast. This system is based on the existing GSI but with ensemble back- ground information incorporated. As a follow-up, this work extends the new system to assimilate real observations to further understand the hybrid scheme. As a first effort to explore the system with real observations, relatively coarse grid resolution （27 km） is used. A case study of typhoon Muifa （2011） is performed to assimilate real observations in- cluding conventional in-situ and satellite data. The hybrid system with flow-dependent ensemble eovariance shows sig- nificant improvements with respect to track forecast compared to the standard GSI system which in theory is three di- mensional variational analysis （3DVAR）. By comparing the analyses, analysis increments and forecasts, the hybrid sys- tem is found to be potentially able to recognize the existence of TC vortex, adjust its position systematically, better de- scribe the asymmetric structure of typhoon Muifa and maintain the dynamic and thermodynamic balance in typhoon ini- tial field. In addition, a cold-start hybrid approach by using the global ensembles to provide flow-dependent error is test- ed and similar results are revealed with those from cycled GSI-ETKF approach.展开更多
文摘为全面、即时搜集分散于互联网上游离的气象数据,满足各行业、各领域、各学科科研部门的数据需求,提出使用Google MEAN Stack全栈技术开发基于Cheer IO的高效定向爬虫,充分利用Node.js高性能I/O的特性,实现气象信息的快速搜集。同时将技术栈与地理信息系统技术、数据可视化技术以及云计算技术相结合,通过地理信息系统的数据存储、查询、自动制图、统计分析等功能对信息进行分析和处理,在阿里云平台上构建了一个能抓取并存储海量数据、提供实时气象数据的应用系统,提供便捷的检索、查询功能,有较强的实用性。本文结合气象数据爬虫的解决方案,对MEAN Stack数据爬虫的开发框架、项目架构以及爬虫核心技术(抓取目标策略、网页分析算法、多线程并发运算等)进行了深入分析研究与实现。
文摘In this paper we summarize the characteristics of the dishpan experiment, the principle of substance revolving, and the scientific basis of the “retrograde wave in only one direction” with respect to weather data and S. C. OuYang＇s articles in which the fundamental questions in the meteorological theory were pointed out. Furthermore, we discuss the systematic changes involving the concept, theory, and method that substance evolves.
基金Special Research Program for Public Welfare(Meteorology)of China(GYHY200906009,GYHY201006015,GYHY200906007)National Natural Science Foundation of China(4107503541475044)
文摘This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for Medium-Range Weather Forecasts, Japan Meteorological Agency and National Centers for Environmental Prediction in the THORPEX Interactive Grand Global Ensemble(TIGGE) datasets. The multi-model ensemble schemes, namely the bias-removed ensemble mean(BREM) and superensemble(SUP), are compared with the ensemble mean(EMN) and single-model forecasts. Moreover, a new model bias estimation scheme is investigated and applied to the BREM and SUP schemes. The results showed that, compared with single-model forecasts and EMN, the multi-model ensembles of the BREM and SUP schemes can have smaller errors in most cases. However, there were also circumstances where BREM was less skillful than EMN, indicating that using a time-averaged error as model bias is not optimal. A new model bias estimation scheme of the biweight mean is introduced. Through minimizing the negative influence of singular errors, this scheme can obtain a more accurate model bias estimation and improve the BREM forecast skill. The application of the biweight mean in the bias calculation of SUP also resulted in improved skill. The results indicate that the modification of multi-model ensemble schemes through this bias estimation method is feasible.
基金Supported bythe Doctoral Foundation of Education Ministry of China (No.20040056037) .
文摘With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becomes necessary to investigate the effects of the radiation and air pressure on insulation materials. This paper describes the effects of gamma-ray irradiation and reduced pressure on dielectric breakdown of polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) by applying a DC pulse voltage. Both PBN and PBT were irradiated in air up to 100 kGy and then up to 1 000 kGy with a dose rate of 10 kGy/h by using a60Co gamma-source. The effects of total dose and reduced pressure on the time to dielectric breakdown and discharge quantity were discussed. Obtained results show that, while increasing the total dose, the discharge quantity decreased with PBN, but increased with PBT. With decreasing the air pressure, the discharge quantity increased with PBN, but decreased with PBT. With increasing the total dose, the time to dielectric breakdown increased with PBN, but decreased with PBT. With decreasing the air pressure, the time to dielectric breakdown increased with both PBN and PBT. The experimental results suggest that the chemical structure of polybutylene polymers plays a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction.
基金Project for Public Welfare(Meteorology)of China(GYHY201206006)973 Program(2013CB430305)+2 种基金National Natural Science Foundation of China(41575107)Project of Shanghai Meteorological Bureau(YJ201401)Key Project of Science and Technology Commission of Shanghai Municipality(13231203300)
文摘A hybrid GSI （Grid-point Statistical Interpolation）-ETKF （Ensemble Transform Kalman Filter） data assimila- tion system has been recently developed for the WRF （Weather Research and Forecasting） model and tested with simu- lated observations for tropical cyclone （TC） forecast. This system is based on the existing GSI but with ensemble back- ground information incorporated. As a follow-up, this work extends the new system to assimilate real observations to further understand the hybrid scheme. As a first effort to explore the system with real observations, relatively coarse grid resolution （27 km） is used. A case study of typhoon Muifa （2011） is performed to assimilate real observations in- cluding conventional in-situ and satellite data. The hybrid system with flow-dependent ensemble eovariance shows sig- nificant improvements with respect to track forecast compared to the standard GSI system which in theory is three di- mensional variational analysis （3DVAR）. By comparing the analyses, analysis increments and forecasts, the hybrid sys- tem is found to be potentially able to recognize the existence of TC vortex, adjust its position systematically, better de- scribe the asymmetric structure of typhoon Muifa and maintain the dynamic and thermodynamic balance in typhoon ini- tial field. In addition, a cold-start hybrid approach by using the global ensembles to provide flow-dependent error is test- ed and similar results are revealed with those from cycled GSI-ETKF approach.
