Low energy gamma radiation (0.2-10.0) MeV near the Earth's surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons (〉 1 GeV) in terrestrial atmosphere a...Low energy gamma radiation (0.2-10.0) MeV near the Earth's surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons (〉 1 GeV) in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas (Rn-222) that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges (lightning strikes) and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA (Technological Institute of Aeronautics) campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.展开更多
The large-scale computations are often performed in science and engineering areas such as numerical weather forecasting, astrophysics, energy resources exploration, nuclear weapon design, and plasma fusion research et...The large-scale computations are often performed in science and engineering areas such as numerical weather forecasting, astrophysics, energy resources exploration, nuclear weapon design, and plasma fusion research etc. Many applications in these areas need super computing power. The traditional mode of sequential processing cannot meet the demands of those computations, thus, parallel processing(PP) is the main way of high performance computing (HPC) now.展开更多
Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical m...Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical modeling.In March 2011,due to the massive 9.0 earthquakes and ensuing tsunami that struck off the northern coast of the island of Honshu,the Fukushima Nuclear Plant I had the substantial leak of radioactive materials into surrounding environment and atmosphere.To aim at the global dispersion modeling of atmospheric radionuclides from Fukushima Nuclear Accident,this paper presents two approaches of atmospheric dispersion forecasting:ensemble dispersion modeling(EDM) and deterministic dispersion modeling(DDM),conducts the globally dispersion modeling cases for Fukushima nuclear accident,and analyzes and evaluates the simulation results using observation data.In this paper,EDM includes three different perturbation methods:meteorological perturbation method,turbulence perturbation method,and physical parameterization ensemble forecasting method.The simulation results show that the trajectories from EDM have a better performance,which is in better agreement with the atmospheric circulation and observation data; the spread from DDM is slower and not as far as EDM.Additionally,the results from EDM display a better performance in the modeling of transport from Japan to China East Sea on April 4.The reasons for these results are:the techniques of MET and TUR are performed by adding perturbations on mean wind and turbulent velocity,respectively; the various different flow fields will result in far spreading in horizontal and the simulation results closer to observation; PHY is performed by using different diffusion physical parameterizations and produces the perturbations on vertical wind,which results the spreading in smaller range and discontinuous in horizontal.Finally,the comparative analysis between modeling results and observation data shows that all cases results are in good agreement with trends of observed radionuclides surface concentration; however,the modeling surface concentration is smaller than observation,especially in DDM and PHY.Furthermore,the EDM results show that MET and TUR are of more evolutionary advantage than PHY in modeling of average and maximum concentration.Therefore,this study can serve as a reference to atmospheric dispersion and environmental emergency response(EER).展开更多
X-ray bright points (XBPs) are small-scale brightenings in the solar corona. Their counterparts in the lower atmosphere, how- ever, are poorly investigated. In this paper, we study the counterparts of XBPs in the up...X-ray bright points (XBPs) are small-scale brightenings in the solar corona. Their counterparts in the lower atmosphere, how- ever, are poorly investigated. In this paper, we study the counterparts of XBPs in the upper chromosphere where the Hot line center is formed. The XBPs were observed by the X-ray Telescope (XRT) aboard the Hinode spacecraft during the observing plan (HOP0124) in August 2009, coordinated with the Solar Magnetic Activity Research Telescope (SMART) in the Kwasan and Hida Observatory, Kyoto University. It is found that there are 77 Hot brightenings in the same field of view of XRT, and among 57 XBPs, 29 have counterparts in the Hot channel. We found three types of relationship: Types a, b and c, correspond- ing to XBPs appearing first, Hot brightenings occurring first and no respective correspondence between them. Most of the strong XBPs belong to Type a. The Hot counterparts generally have double-kernel structures associated with magnetic bipoles and are cospatial with the footpoints of the XBP loops. The average lag time is -3 minutes. This implies that for Type a the heating, presumably through magnetic reconnection, occurs first in the solar upper atmosphere and then goes downwards along the small-scale magnetic loops that comprise the XBPs. In this case, the thermal conduction plays a dominant role over the non-thermal heating. Only a few events belong to Type b, which could happen when magnetic reconnection occurs in the chromosphere and produces an upward jet which heats the upper atmosphere and causes the XBP. About half of the XBPs belong to Type c. Generally they have weak emission in SXR. About 62% Hot brightenings have no corresponding XBPs. Most of them are weak and have single structures.展开更多
Net Primary Productivity (NPP) is an important parameter, which is closely connected with global climate change, the global carbon balance and cycle. The study of climate- vegetation interaction is the basis for res...Net Primary Productivity (NPP) is an important parameter, which is closely connected with global climate change, the global carbon balance and cycle. The study of climate- vegetation interaction is the basis for research on the responses of terrestrial ecosystemto global change and mainly comprises two important components: climate vegetation classification and the NPP of the natural vegetation. Comparing NPP estimated from the classification indices-based model with NPP derived from measurements at 3767 sites in China indicated that the classification indices-based model was capable of estimating large scale NPP. Annual cumulative temperature above 0~C and a moisture index, two main factors affecting NPP, were spatially plotted with the ArcGIS grid tool based on measured data in 2348 meteorological stations from 1961 to 2006. The distribution of NPP for potential vegetation classes under present climate conditions was simulated by the classification indices-based model. The model estimated the total NPP of potential terrestrial vegetation of China to fluctuate between 1.93 and 4.54 Pg C year-1. It pro- vides a reliable means for scaling-up from site to regional scales, and the findings could potentially favor China's position in reducing global warming gases as outlined in the Kyoto Protocol in order to fulfill China's commitment of reducing greenhouse gases.展开更多
The Regional Atmospheric Modeling System (RAMS) has been used to investigate the effects of varied giant cloud condensation nuclei (GCCN) concentrations on precipitation characteristics of the spring hailstorms in a s...The Regional Atmospheric Modeling System (RAMS) has been used to investigate the effects of varied giant cloud condensation nuclei (GCCN) concentrations on precipitation characteristics of the spring hailstorms in a semi-arid region. The simulation result shows that this variation has significant effects on the storm microphysical processes as well as on the surface precipitation. The coverage of hail and hail mixing ratio maxima in cloud increases with greater GCCN concentrations. The accumulation zone structure benefits the growth of hail particles. Higher GCCN concentrations lead to more supercooled rain water and cloud water available for freezing. This simulation also shows that increasing GCCN concentrations may produce more rainfall on the surface but less hail precipitation, and the total accumulated precipitation increases while the ice phase precipitation decreases. This effect is stronger in polluted air than in clean air. The surface flow field changes with different GCCN concentrations. The identification index of spring hailstorm is different from that of summer hailstorm with a different aerosol background.展开更多
Unmanned aerial vehicle(UAV) remote imaging is affected by the bad weather, and the obtained images have the disadvantages of low contrast, complex texture and blurring. In this paper, we propose a blind deconvolution...Unmanned aerial vehicle(UAV) remote imaging is affected by the bad weather, and the obtained images have the disadvantages of low contrast, complex texture and blurring. In this paper, we propose a blind deconvolution model based on multiple scattering atmosphere point spread function(APSF) estimation to recovery the remote sensing image. According to Narasimhan analytical theory, a new multiple scattering restoration model is established based on the improved dichromatic model. Then using the L0 norm sparse priors of gradient and dark channel to estimate APSF blur kernel, the fast Fourier transform is used to recover the original clear image by Wiener filtering. By comparing with other state-of-the-art methods, the proposed method can correctly estimate blur kernel, effectively remove the atmospheric degradation phenomena, preserve image detail information and increase the quality evaluation indexes.展开更多
文摘为了在核污染事故处理时提供精细化预警,以辽宁省某核电站周边部分重要目标(大衣屯、大周屯、红沿河镇、驼山乡、西杨乡、复大线应急撤离线路)为研究对象,将环境保护指挥自动化系统C4ISRE(Command,Control,Communications,Computer,Intelligence,Surveillance,Reconnaissance,Environmental Impact Assessment)与HYSPLIT 4.9模型相耦合,采用NCEP(美国国家环境预报中心)的FNL全球气象数据对核污染扩散轨迹进行仿真研究.结果表明:自模拟初始时间2014-04-01T00:00:00.00开始,进、出大衣屯边界时间分别为00:06:16.560、00:06:49.000,历时31.340 s;由西向东横穿过大周屯,进、出时间分别为于00:06:16.56到达大衣屯北部边界,于00:06:46.90扩散出大衣屯边界,经过大衣屯区域耗时共计29.00 s;核污染气团于00:15:30.85到达大周屯上空500 m处,由西向东横穿过大周屯,于00:15:46.05离开大周屯上空,过程耗时15.20 s;核污染气团于00:32:14.25经过重要应急撤离线路2(复大线),全程耗时32 min 14.25 s.核污染气团与从2014-04-01T00:00:00.000进入红沿河镇上空500 m区域,于00:24:27.00扩散出,全程历时24 min 27.00 s;进、出驼山乡上空500 m区域的时间分别为00:24:28、00:51:00,历时26 min 32.00 s;进、出西杨乡上空的时间分别为00:51:01、01:05:4.70,历时14 min 37.00 s;重点区域大衣屯和大周屯行政区的预警时间分别为376.56、930.85 s,重点撤离线路2区域预警时间为1 934.25 s.
文摘Low energy gamma radiation (0.2-10.0) MeV near the Earth's surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons (〉 1 GeV) in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas (Rn-222) that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges (lightning strikes) and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA (Technological Institute of Aeronautics) campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.
文摘The large-scale computations are often performed in science and engineering areas such as numerical weather forecasting, astrophysics, energy resources exploration, nuclear weapon design, and plasma fusion research etc. Many applications in these areas need super computing power. The traditional mode of sequential processing cannot meet the demands of those computations, thus, parallel processing(PP) is the main way of high performance computing (HPC) now.
基金supported in part by the National Natural Science Foundation of China(Grant No.41305104)the Special Fund for Meteo-scientific Research in the Public Interest(Grant No.GYHY201306061)
文摘Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical modeling.In March 2011,due to the massive 9.0 earthquakes and ensuing tsunami that struck off the northern coast of the island of Honshu,the Fukushima Nuclear Plant I had the substantial leak of radioactive materials into surrounding environment and atmosphere.To aim at the global dispersion modeling of atmospheric radionuclides from Fukushima Nuclear Accident,this paper presents two approaches of atmospheric dispersion forecasting:ensemble dispersion modeling(EDM) and deterministic dispersion modeling(DDM),conducts the globally dispersion modeling cases for Fukushima nuclear accident,and analyzes and evaluates the simulation results using observation data.In this paper,EDM includes three different perturbation methods:meteorological perturbation method,turbulence perturbation method,and physical parameterization ensemble forecasting method.The simulation results show that the trajectories from EDM have a better performance,which is in better agreement with the atmospheric circulation and observation data; the spread from DDM is slower and not as far as EDM.Additionally,the results from EDM display a better performance in the modeling of transport from Japan to China East Sea on April 4.The reasons for these results are:the techniques of MET and TUR are performed by adding perturbations on mean wind and turbulent velocity,respectively; the various different flow fields will result in far spreading in horizontal and the simulation results closer to observation; PHY is performed by using different diffusion physical parameterizations and produces the perturbations on vertical wind,which results the spreading in smaller range and discontinuous in horizontal.Finally,the comparative analysis between modeling results and observation data shows that all cases results are in good agreement with trends of observed radionuclides surface concentration; however,the modeling surface concentration is smaller than observation,especially in DDM and PHY.Furthermore,the EDM results show that MET and TUR are of more evolutionary advantage than PHY in modeling of average and maximum concentration.Therefore,this study can serve as a reference to atmospheric dispersion and environmental emergency response(EER).
基金supported by the National Basic Research Program of China (Grant No.2011CB811402)the National Natural Science Foundation of China (Grant Nos.10878002,10610099,10933003,10673004,10073005,10403003,and 11025314)
文摘X-ray bright points (XBPs) are small-scale brightenings in the solar corona. Their counterparts in the lower atmosphere, how- ever, are poorly investigated. In this paper, we study the counterparts of XBPs in the upper chromosphere where the Hot line center is formed. The XBPs were observed by the X-ray Telescope (XRT) aboard the Hinode spacecraft during the observing plan (HOP0124) in August 2009, coordinated with the Solar Magnetic Activity Research Telescope (SMART) in the Kwasan and Hida Observatory, Kyoto University. It is found that there are 77 Hot brightenings in the same field of view of XRT, and among 57 XBPs, 29 have counterparts in the Hot channel. We found three types of relationship: Types a, b and c, correspond- ing to XBPs appearing first, Hot brightenings occurring first and no respective correspondence between them. Most of the strong XBPs belong to Type a. The Hot counterparts generally have double-kernel structures associated with magnetic bipoles and are cospatial with the footpoints of the XBP loops. The average lag time is -3 minutes. This implies that for Type a the heating, presumably through magnetic reconnection, occurs first in the solar upper atmosphere and then goes downwards along the small-scale magnetic loops that comprise the XBPs. In this case, the thermal conduction plays a dominant role over the non-thermal heating. Only a few events belong to Type b, which could happen when magnetic reconnection occurs in the chromosphere and produces an upward jet which heats the upper atmosphere and causes the XBP. About half of the XBPs belong to Type c. Generally they have weak emission in SXR. About 62% Hot brightenings have no corresponding XBPs. Most of them are weak and have single structures.
文摘Net Primary Productivity (NPP) is an important parameter, which is closely connected with global climate change, the global carbon balance and cycle. The study of climate- vegetation interaction is the basis for research on the responses of terrestrial ecosystemto global change and mainly comprises two important components: climate vegetation classification and the NPP of the natural vegetation. Comparing NPP estimated from the classification indices-based model with NPP derived from measurements at 3767 sites in China indicated that the classification indices-based model was capable of estimating large scale NPP. Annual cumulative temperature above 0~C and a moisture index, two main factors affecting NPP, were spatially plotted with the ArcGIS grid tool based on measured data in 2348 meteorological stations from 1961 to 2006. The distribution of NPP for potential vegetation classes under present climate conditions was simulated by the classification indices-based model. The model estimated the total NPP of potential terrestrial vegetation of China to fluctuate between 1.93 and 4.54 Pg C year-1. It pro- vides a reliable means for scaling-up from site to regional scales, and the findings could potentially favor China's position in reducing global warming gases as outlined in the Kyoto Protocol in order to fulfill China's commitment of reducing greenhouse gases.
基金supported by National Natural Science Foundation of China (Grant Nos. 40875080 and 40875002)Ministry of Science and Technology of China (Grant No. 2006BAC12B01-01)
文摘The Regional Atmospheric Modeling System (RAMS) has been used to investigate the effects of varied giant cloud condensation nuclei (GCCN) concentrations on precipitation characteristics of the spring hailstorms in a semi-arid region. The simulation result shows that this variation has significant effects on the storm microphysical processes as well as on the surface precipitation. The coverage of hail and hail mixing ratio maxima in cloud increases with greater GCCN concentrations. The accumulation zone structure benefits the growth of hail particles. Higher GCCN concentrations lead to more supercooled rain water and cloud water available for freezing. This simulation also shows that increasing GCCN concentrations may produce more rainfall on the surface but less hail precipitation, and the total accumulated precipitation increases while the ice phase precipitation decreases. This effect is stronger in polluted air than in clean air. The surface flow field changes with different GCCN concentrations. The identification index of spring hailstorm is different from that of summer hailstorm with a different aerosol background.
基金supported by the National Natural Science Foundation of China(No.61405191)
文摘Unmanned aerial vehicle(UAV) remote imaging is affected by the bad weather, and the obtained images have the disadvantages of low contrast, complex texture and blurring. In this paper, we propose a blind deconvolution model based on multiple scattering atmosphere point spread function(APSF) estimation to recovery the remote sensing image. According to Narasimhan analytical theory, a new multiple scattering restoration model is established based on the improved dichromatic model. Then using the L0 norm sparse priors of gradient and dark channel to estimate APSF blur kernel, the fast Fourier transform is used to recover the original clear image by Wiener filtering. By comparing with other state-of-the-art methods, the proposed method can correctly estimate blur kernel, effectively remove the atmospheric degradation phenomena, preserve image detail information and increase the quality evaluation indexes.