基于多源卫星资料特别是微波定量化产品开展综合分析,是卫星遥感台风监测技术未来发展的必然趋势。更客观的综合定强技术有助于在总体上提高台风强度的预报水平。以2013年第23号强台风"菲特"为例,采用台风最佳路径结果对国内...基于多源卫星资料特别是微波定量化产品开展综合分析,是卫星遥感台风监测技术未来发展的必然趋势。更客观的综合定强技术有助于在总体上提高台风强度的预报水平。以2013年第23号强台风"菲特"为例,采用台风最佳路径结果对国内外常见的几家热带气旋预报机构(中央气象台、上海气象局、日本气象厅、美国关岛、美国国家海洋和大气局(National Oceanic and Atmospheric Administration,NOAA)、美国国家环境卫星数据和信息服务中心(National Environmental Satellite Data and Informa,tion Service,NESDIS)和美国热带气旋中心(Coperative Institute for Meteorological Satellite Studies,CIMSS))的定位、定强结果及导致结果差异的可能原因进行了详细的对比分析。结果表明,各家机构的路径监测结果较一致,白天的结果比夜间更可靠。中央气象台、上海气象局、美国关岛和美国NOAA区域中尺度气象局(Regional and Mesoscale MeteorologyBranch,RAMMB)四家机构的风速预报结果最接近。中央气象台的预报误差最小,精度最高;其次是上海气象局、美国关岛和RAMMB;美国CIMSS发布的结果最不稳定,日本气象厅发布的结果的误差整体偏低。分析结果对台风一线的业务值班人员具有较好的借鉴意义。展开更多
Using data from the Large Area X-ray Proportional Counter(LAXPC)on the AstroSat satellite,we observed Type-1 thermonuclear X-ray bursts from the low mass X-ray binary neutron star 4 U 1323-62.Observations of 4 U 1323-...Using data from the Large Area X-ray Proportional Counter(LAXPC)on the AstroSat satellite,we observed Type-1 thermonuclear X-ray bursts from the low mass X-ray binary neutron star 4 U 1323-62.Observations of 4 U 1323-62 that were carried out during the performance verification phase of the AstroSat satellite indicated six thermonuclear X-ray bursts in a total effective exposure of^49.5 ks for about two consecutive days.Recurrence time of the detected thermonuclear bursts is in accordance with the orbital period of the source,~9400 s.Moreover,the light curve of 4 U 1323-62 revealed the presence of two dips.We present the results from time-resolved spectroscopy performed during all of the six X-ray bursts and also report the detection of a known low frequency quasi-periodic oscillation(LFQPO)at^1 Hz from the source.However,any evidence of kilohertz QPO was not found.We have shown the burst profile at different energy ranges.Assuming a distance of 10 kpc,we observed a mean flux of^1.8×10^-9 erg cm^2 s^-1.The radius of the blackbody is found to be highly consistent with the blackbody temperature and the blackbody flux of the bursts.展开更多
文摘基于多源卫星资料特别是微波定量化产品开展综合分析,是卫星遥感台风监测技术未来发展的必然趋势。更客观的综合定强技术有助于在总体上提高台风强度的预报水平。以2013年第23号强台风"菲特"为例,采用台风最佳路径结果对国内外常见的几家热带气旋预报机构(中央气象台、上海气象局、日本气象厅、美国关岛、美国国家海洋和大气局(National Oceanic and Atmospheric Administration,NOAA)、美国国家环境卫星数据和信息服务中心(National Environmental Satellite Data and Informa,tion Service,NESDIS)和美国热带气旋中心(Coperative Institute for Meteorological Satellite Studies,CIMSS))的定位、定强结果及导致结果差异的可能原因进行了详细的对比分析。结果表明,各家机构的路径监测结果较一致,白天的结果比夜间更可靠。中央气象台、上海气象局、美国关岛和美国NOAA区域中尺度气象局(Regional and Mesoscale MeteorologyBranch,RAMMB)四家机构的风速预报结果最接近。中央气象台的预报误差最小,精度最高;其次是上海气象局、美国关岛和RAMMB;美国CIMSS发布的结果最不稳定,日本气象厅发布的结果的误差整体偏低。分析结果对台风一线的业务值班人员具有较好的借鉴意义。
基金support from the Indian Space Research Organization(ISRO)and AstroSat science support cell in various aspects of instrument building,testing,software development and mission operation during the payload verification phase。
文摘Using data from the Large Area X-ray Proportional Counter(LAXPC)on the AstroSat satellite,we observed Type-1 thermonuclear X-ray bursts from the low mass X-ray binary neutron star 4 U 1323-62.Observations of 4 U 1323-62 that were carried out during the performance verification phase of the AstroSat satellite indicated six thermonuclear X-ray bursts in a total effective exposure of^49.5 ks for about two consecutive days.Recurrence time of the detected thermonuclear bursts is in accordance with the orbital period of the source,~9400 s.Moreover,the light curve of 4 U 1323-62 revealed the presence of two dips.We present the results from time-resolved spectroscopy performed during all of the six X-ray bursts and also report the detection of a known low frequency quasi-periodic oscillation(LFQPO)at^1 Hz from the source.However,any evidence of kilohertz QPO was not found.We have shown the burst profile at different energy ranges.Assuming a distance of 10 kpc,we observed a mean flux of^1.8×10^-9 erg cm^2 s^-1.The radius of the blackbody is found to be highly consistent with the blackbody temperature and the blackbody flux of the bursts.
