In this study, an extension of the TREC （Tracking Radar Echo by Correlations） technique, named Tropical Cyclone （TC） circulation TREC （T-TREC）, is developed to retrieve the winds of landfalling typhoons in China...In this study, an extension of the TREC （Tracking Radar Echo by Correlations） technique, named Tropical Cyclone （TC） circulation TREC （T-TREC）, is developed to retrieve the winds of landfalling typhoons in China. The T-TREC analysis is performed on a polar grid centered at the TC center, using arc-shaped correlation cells and an arc-shaped search area. The search for the best correlation match is confined along the cyclonic direction with a limited search distance in the radial direction based on the cyclonic circulation characteristics of TCs in the Northern Hemisphere. The TC center is determined objectively using reflectivity data while the Doppler radar radial velocities are incorporated to estimate the search range and create a velocity correlation matrix as auxiliary constraints. The T-TREC was applied to the landfalling Typhoon Saomai （0608） observed by Chinese next generation Weather Surveillance Radar 1998 Doppler （CINRAD WSR-98D） on the southeast coast of China. The results show that the T-TREC has the ability to estimate the typhoon circulation with an average bias of 4 m s -1 . The incorporation of radial velocity data could distinctively improve wind retrievals for intense typhoons, especially by reducing the underestimation caused by fairly uniform reflectivity patterns in the vicinity of the eyewall and the outer rainband. A quantitative evaluation of the influence of typhoon center and cell size on the wind estimation demonstrates that the quality of the T-TREC retrieved wind circulation depends on the estimation of the typhoon center. A 4-km deviation of the TC center may result in a 10% increase in the retrieved wind error. The effect of cell size depends on the typhoon scale： better wind retrieval results can be obtained for a smaller typhoon.展开更多
基于WRF模式及其Hybrid集合-变分同化系统,比较研究了雷达径向速度(V_r)同化和T-TREC(Typhoon-Tracking radar echoes by correlation)反演风同化对台风灿都(2010)分析和预报的影响。为了探索最适合登陆台风预报的雷达资料同化策略,在研...基于WRF模式及其Hybrid集合-变分同化系统,比较研究了雷达径向速度(V_r)同化和T-TREC(Typhoon-Tracking radar echoes by correlation)反演风同化对台风灿都(2010)分析和预报的影响。为了探索最适合登陆台风预报的雷达资料同化策略,在研究V_r循环同化和T-TREC循环同化的基础上,考虑到两种雷达风场资料各自的优势,提出了合理利用两种雷达风场资料的联合同化策略,即在循环同化的首次分析中同化T-TREC风,而在之后的分析中同化V_r资料。研究三种不同的雷达资料同化策略发现,V_r直接同化虽能改善台风分析和预报,但其依赖于较多的同化次数,这会导致确定性预报的启动时间较晚,不利于台风业务预报。相比之下,由于T-TREC资料观测范围远、风场结构完整,T-TREC循环同化策略只经过较少次数的同化分析即能显著改善台风强度预报;然而受T-TREC资料自身反演误差的影响,增加同化次数反而不利于提高预报效果。当联合利用这两种雷达风场时,联合同化策略在不同同化时间窗下的预报表现均最优。展开更多
为分析职业性苯中毒工人外周血单个核细胞中T细胞受体删除DNA环(TRECs)的含量,了解苯中毒工人胸腺近期输出功能变化,采用实时荧光定量聚合酶链反应(real time PCR)和TaqMan方法检测苯中毒和健康人外周血单个核细胞中TRECs的含量。结果显...为分析职业性苯中毒工人外周血单个核细胞中T细胞受体删除DNA环(TRECs)的含量,了解苯中毒工人胸腺近期输出功能变化,采用实时荧光定量聚合酶链反应(real time PCR)和TaqMan方法检测苯中毒和健康人外周血单个核细胞中TRECs的含量。结果显示,TRECs含量苯中毒观察对象2·97±1·31、轻度苯中毒1·73±1·11、中度苯中毒2·28±1·44、重度苯中毒1·91±1·95,各组患者每1000个外周血单个核细胞中TRECs含量均明显低于健康组7·39±6·83(P<0·05),轻度和重度苯中毒组TRECs含量显著低于苯中毒观察对象组(P<0·05)。重度苯中毒组接苯时间>3的工人TRECs含量显著低于接苯时间≤3年者,苯中毒观察对象组接苯时间>5年的工人TRECs含量显著低于≤5年者(P<0·05)。提示苯中毒患者胸腺近期输出功能低下。展开更多
基金Supported by the "973" National Key Basic Research Program of China under Grant No. 2009CB421502the National Natural Science Foundation of China under Grant Nos. 40505004, 40333025, and 40975011
文摘In this study, an extension of the TREC （Tracking Radar Echo by Correlations） technique, named Tropical Cyclone （TC） circulation TREC （T-TREC）, is developed to retrieve the winds of landfalling typhoons in China. The T-TREC analysis is performed on a polar grid centered at the TC center, using arc-shaped correlation cells and an arc-shaped search area. The search for the best correlation match is confined along the cyclonic direction with a limited search distance in the radial direction based on the cyclonic circulation characteristics of TCs in the Northern Hemisphere. The TC center is determined objectively using reflectivity data while the Doppler radar radial velocities are incorporated to estimate the search range and create a velocity correlation matrix as auxiliary constraints. The T-TREC was applied to the landfalling Typhoon Saomai （0608） observed by Chinese next generation Weather Surveillance Radar 1998 Doppler （CINRAD WSR-98D） on the southeast coast of China. The results show that the T-TREC has the ability to estimate the typhoon circulation with an average bias of 4 m s -1 . The incorporation of radial velocity data could distinctively improve wind retrievals for intense typhoons, especially by reducing the underestimation caused by fairly uniform reflectivity patterns in the vicinity of the eyewall and the outer rainband. A quantitative evaluation of the influence of typhoon center and cell size on the wind estimation demonstrates that the quality of the T-TREC retrieved wind circulation depends on the estimation of the typhoon center. A 4-km deviation of the TC center may result in a 10% increase in the retrieved wind error. The effect of cell size depends on the typhoon scale： better wind retrieval results can be obtained for a smaller typhoon.
文摘基于WRF模式及其Hybrid集合-变分同化系统,比较研究了雷达径向速度(V_r)同化和T-TREC(Typhoon-Tracking radar echoes by correlation)反演风同化对台风灿都(2010)分析和预报的影响。为了探索最适合登陆台风预报的雷达资料同化策略,在研究V_r循环同化和T-TREC循环同化的基础上,考虑到两种雷达风场资料各自的优势,提出了合理利用两种雷达风场资料的联合同化策略,即在循环同化的首次分析中同化T-TREC风,而在之后的分析中同化V_r资料。研究三种不同的雷达资料同化策略发现,V_r直接同化虽能改善台风分析和预报,但其依赖于较多的同化次数,这会导致确定性预报的启动时间较晚,不利于台风业务预报。相比之下,由于T-TREC资料观测范围远、风场结构完整,T-TREC循环同化策略只经过较少次数的同化分析即能显著改善台风强度预报;然而受T-TREC资料自身反演误差的影响,增加同化次数反而不利于提高预报效果。当联合利用这两种雷达风场时,联合同化策略在不同同化时间窗下的预报表现均最优。
文摘为分析职业性苯中毒工人外周血单个核细胞中T细胞受体删除DNA环(TRECs)的含量,了解苯中毒工人胸腺近期输出功能变化,采用实时荧光定量聚合酶链反应(real time PCR)和TaqMan方法检测苯中毒和健康人外周血单个核细胞中TRECs的含量。结果显示,TRECs含量苯中毒观察对象2·97±1·31、轻度苯中毒1·73±1·11、中度苯中毒2·28±1·44、重度苯中毒1·91±1·95,各组患者每1000个外周血单个核细胞中TRECs含量均明显低于健康组7·39±6·83(P<0·05),轻度和重度苯中毒组TRECs含量显著低于苯中毒观察对象组(P<0·05)。重度苯中毒组接苯时间>3的工人TRECs含量显著低于接苯时间≤3年者,苯中毒观察对象组接苯时间>5年的工人TRECs含量显著低于≤5年者(P<0·05)。提示苯中毒患者胸腺近期输出功能低下。
