Combining with the exigent demand of the development of satellite gravimetry system in China, aiming at the determination of technical indexes of gravity satellite orbit parameters, on the basis of the numerical exper...Combining with the exigent demand of the development of satellite gravimetry system in China, aiming at the determination of technical indexes of gravity satellite orbit parameters, on the basis of the numerical experiments and results analysis, the design indexes of gravity satellite orbit height, inter-satellite range and the orbit inclination are analyzed and calculated, and the issues towards twin gravity satellites such as coherence requirement of the orbit semi-major axes, control requirement of the pitch angle and time interval requirement to keep twin satellites formation in mobility are diseussed. Results show that the satellite orbit height is 400 km to 500 km, the inter-satellite range is about 220 km, the satellite orbit inclination is between polar orbit and sun-synchronous orbit, the semi-major axes difference of twin satellites orbit is within ± 70. 146 m, the pitch angle of twin satellites is about 0.9 degree, and the time interval to keep twin satellites formation in mobility is 7 days to 15 days.展开更多
This study examines the artificial influence of increasing the SST resolution on the storm track over the North Pacific in ERA-Interim.Along with the mesoscale oceanic eddies and fronts resolved during the high-resolu...This study examines the artificial influence of increasing the SST resolution on the storm track over the North Pacific in ERA-Interim.Along with the mesoscale oceanic eddies and fronts resolved during the high-resolution-SST period,the low-level storm track strengthens northward,reaching more than 30%of the maximum values in the low-resolution-SST period after removing the influence of ENSO.The mesoscale structure firstly imprints on the marine atmospheric boundary layer,which then leads to changes in turbulent heat flux and near-surface convergence,forcing a secondary circulation into the free atmosphere,strengthening the vertical eddy heat,momentum and specific humidity fluxes,and contributing to the enhancement of the storm track.Results from a high-resolution atmospheric model further indicate the changes in the storm track due to the mesoscale SST and their relationship.展开更多
Tropical Cyclone (TC) tracks over the western North Pacific (WNP) during 1949–2007, obtained from China Meteorological Administration/Shanghai Typhoon institute, are classified into three track types. These types are...Tropical Cyclone (TC) tracks over the western North Pacific (WNP) during 1949–2007, obtained from China Meteorological Administration/Shanghai Typhoon institute, are classified into three track types. These types are the main pathways by which TCs influence the coast of East Asia. The relationships between local sea surface temperature (SST) in WNP and TC tracks are revealed. Results show that the local SST plays an important role in TC tracks, though the relationships between local SST and the frequencies of different TC tracks are very dissimilar. The local SST has significant positive correlation with northwest-path TCs, and negative correlation with recurving-path TCs. However, the west-path TCs do not have statistically significant relationship with the local SST. The upper sea temperature anomalies which influence TC tracks last about six months before TC occurrence. Further analysis indicates that the ocean conditions influence TC tracks by modifying the atmospheric circulation, and then the modified atmospheric circulation can affect TC’s genesis location and motion.展开更多
With the Gravity Recovery and Climate Experiment {GRACE） mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To i...With the Gravity Recovery and Climate Experiment {GRACE） mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To illustrate the underlying principle and algorithm, a detailed study is made on the K-band ranging （KBR） assembly, which includes the measurement principles, modeling of noises, the generation of Level 1A data from that of Level 0 as well as Level IA to Level IB data processing.展开更多
利用欧洲中期天气预报中心ECMWF(European Center for Medium-range Weather Forecast)逐日再分析资料(ERA40),通过经验正交函数(empirical orthogonal function,EOF)分解发现,冬季北太平洋东部风暴轴有着显著的年际变化特征:第一变化...利用欧洲中期天气预报中心ECMWF(European Center for Medium-range Weather Forecast)逐日再分析资料(ERA40),通过经验正交函数(empirical orthogonal function,EOF)分解发现,冬季北太平洋东部风暴轴有着显著的年际变化特征:第一变化模态为在气候平均位置南北相反的偶极子变化型,第二变化模态为在气候平均位置处一致增强或减弱的变化型,第三变化模态为三极子的变化型。进一步的回归分析发现:当东部风暴轴南压(北抬)时,同期冬季是一种厄尔尼诺(拉尼娜)年海温异常空间分布型,中纬度北太平洋海区以及赤道中、东海区,冬季冷(暖)异常的洋面上是异常低压(高压),对流层中层是太平洋—北美型(Pacific-North American Pattern,PNA)遥相关的正(负)位相;当东部风暴轴增强(减弱)时,同期冬季黑潮区海温偏暖(偏冷),对流层中层表现为西太平洋型(West Pacific Pattern,WP)遥相关的正(负)位相;当东部风暴轴呈现西北—东南+-+(-+-)相间三极子的分布时,同期冬季巴布亚新几内亚附近海温异常偏暖(冷),夏威夷附近海温异常偏冷(暖),冬季冷(暖)异常的洋面上是异常低(高)压,对流层中层表现出类似PNA正(负)位相。EOF分解各模态所对应时间系数与阿留申低压(Aleutian Low,AL)指数、PNA指数、Nino3指数、WP指数、黑潮海温(Kuroshio Current,KC)指数之间存在显著的相关,这些证明了东部风暴轴与同期大气环流及SST异常之间的联系。展开更多
Climalological features of mid-latitude blocking occurring over the North Pacific Ocean during 52 winters (December to February) of 1948/1949-1999/2000 are statistically analyzed based on NCEP/ NCAR reanalysis data. S...Climalological features of mid-latitude blocking occurring over the North Pacific Ocean during 52 winters (December to February) of 1948/1949-1999/2000 are statistically analyzed based on NCEP/ NCAR reanalysis data. Significant interannual variation with a period of about 3-7 years as well as decadal variability is found by wavelet analysis and power spectrum analysis. A decreasing trend of the 2-7 year bandscale-averaged variance occurs throughout the 52 years and an abrupt shift from a higher state to a lower state during the 1970s is also found, which suggests an interdecadal variation of the North Pacific blocking. The possible relationship between the variability of blocking and sea surface temperature (SST), storm tracks and teleconnection are shown using composite analysis. In strong blocking anomaly winter (SBW), the geopotential height anomaly at 500 hPa exhibits a typical PNA (Pacific-North American)-like wave-train pattern in the North Pacific. The storm tracks, representing the activity of transient eddies, extend northeastward to the western coast of North America along the mid latitudes of about 40°-50°N, with the SST anomaly exhibiting a Pacific decadal oscillation (PDO) mode at mid-latitude and a La Niña-like pattern along the equator. Contrasting features appear in weak blocking anomaly winter (WBW).展开更多
基于中尺度大气模式WRF(Weather Research and Forecasting Model),首先对2007年3次船舶辐射通量观测进行模拟,以检验WRF对长波和短波辐射通量的模拟能力,结果表明使用中国近海海洋环境数值预报系统环流模式POM(Princeton Ocean Model)...基于中尺度大气模式WRF(Weather Research and Forecasting Model),首先对2007年3次船舶辐射通量观测进行模拟,以检验WRF对长波和短波辐射通量的模拟能力,结果表明使用中国近海海洋环境数值预报系统环流模式POM(Princeton Ocean Model)模拟的高时空分辨率的海洋表层温度能够显著改进短波辐射通量的模拟,而对长波辐射通量模拟的改进不明显。然后,将业务化运行的中国近海海洋环境数值预报系统后报的逐时海洋表面温度(SST)作为WRF底边界条件,对2008年15号强台风"蔷薇"(Jangmi)过程进行了数值后报试验。结果表明,与使用NCEP/NCAR的SST试验后报的台风中心位置偏差相比,使用高时空分辨率的SST能够较为显著地改善"蔷薇"的路径模拟,台风中心位置模拟偏差减少11%,尤其在台风减弱阶段,台风中心位置模拟偏差减少37%。台风强度在台风发展的不同阶段对下垫面SST的变化敏感性不同。台风路径附近的海表面温度下降会导致海洋向大气输送的热量减少从而减弱台风强度。展开更多
基金supported by the National Natural Science Foundation of China(41174026,41104047,41174017)the Key laboratory Foundation of Geo-space Environment and Geodesy of Ministry of Education(11-01-03)
文摘Combining with the exigent demand of the development of satellite gravimetry system in China, aiming at the determination of technical indexes of gravity satellite orbit parameters, on the basis of the numerical experiments and results analysis, the design indexes of gravity satellite orbit height, inter-satellite range and the orbit inclination are analyzed and calculated, and the issues towards twin gravity satellites such as coherence requirement of the orbit semi-major axes, control requirement of the pitch angle and time interval requirement to keep twin satellites formation in mobility are diseussed. Results show that the satellite orbit height is 400 km to 500 km, the inter-satellite range is about 220 km, the satellite orbit inclination is between polar orbit and sun-synchronous orbit, the semi-major axes difference of twin satellites orbit is within ± 70. 146 m, the pitch angle of twin satellites is about 0.9 degree, and the time interval to keep twin satellites formation in mobility is 7 days to 15 days.
基金National Key R&D Program for Developing Basic Sciences(2018YFA0605703,2016YFC1401401)the National Natural Science Foundation of China(Grant Nos.41490642,41776030,41806034,4160501)the research project of the National University of Defense Technology(ZK20-45 and ZK17-02-010).
文摘This study examines the artificial influence of increasing the SST resolution on the storm track over the North Pacific in ERA-Interim.Along with the mesoscale oceanic eddies and fronts resolved during the high-resolution-SST period,the low-level storm track strengthens northward,reaching more than 30%of the maximum values in the low-resolution-SST period after removing the influence of ENSO.The mesoscale structure firstly imprints on the marine atmospheric boundary layer,which then leads to changes in turbulent heat flux and near-surface convergence,forcing a secondary circulation into the free atmosphere,strengthening the vertical eddy heat,momentum and specific humidity fluxes,and contributing to the enhancement of the storm track.Results from a high-resolution atmospheric model further indicate the changes in the storm track due to the mesoscale SST and their relationship.
基金National Natural Science Foundation of China (40775043)National Basic Research Program "973" of China (2006CB403600)Specialized Research Fund for the Doctoral Program of Higher Education (200802840022)
文摘Tropical Cyclone (TC) tracks over the western North Pacific (WNP) during 1949–2007, obtained from China Meteorological Administration/Shanghai Typhoon institute, are classified into three track types. These types are the main pathways by which TCs influence the coast of East Asia. The relationships between local sea surface temperature (SST) in WNP and TC tracks are revealed. Results show that the local SST plays an important role in TC tracks, though the relationships between local SST and the frequencies of different TC tracks are very dissimilar. The local SST has significant positive correlation with northwest-path TCs, and negative correlation with recurving-path TCs. However, the west-path TCs do not have statistically significant relationship with the local SST. The upper sea temperature anomalies which influence TC tracks last about six months before TC occurrence. Further analysis indicates that the ocean conditions influence TC tracks by modifying the atmospheric circulation, and then the modified atmospheric circulation can affect TC’s genesis location and motion.
基金the project entitled"Advanced Gravity Measurement in Space"supported by the National Space Science Center,Chinese Academy of Sciences Profs.Wenrui Hu and Houze Xu's effort to promote satellite gravity research in China motivated the feasibility study in the first placeSupport from National Natural Science Foundation of China(11305255,11171329 and 41404019)funding from State Key Laboratory of Geodesy and Earth's Dynamics,Institute of Geodesy and Geophysics,Chinese Academy of Sciences(SKLGED2013-3-8-E)are acknowledged
文摘With the Gravity Recovery and Climate Experiment {GRACE） mission as the prime example, an overview is given on the management and processing of Level IA data of a low-low satellite to satellite tracking mission. To illustrate the underlying principle and algorithm, a detailed study is made on the K-band ranging （KBR） assembly, which includes the measurement principles, modeling of noises, the generation of Level 1A data from that of Level 0 as well as Level IA to Level IB data processing.
文摘利用欧洲中期天气预报中心ECMWF(European Center for Medium-range Weather Forecast)逐日再分析资料(ERA40),通过经验正交函数(empirical orthogonal function,EOF)分解发现,冬季北太平洋东部风暴轴有着显著的年际变化特征:第一变化模态为在气候平均位置南北相反的偶极子变化型,第二变化模态为在气候平均位置处一致增强或减弱的变化型,第三变化模态为三极子的变化型。进一步的回归分析发现:当东部风暴轴南压(北抬)时,同期冬季是一种厄尔尼诺(拉尼娜)年海温异常空间分布型,中纬度北太平洋海区以及赤道中、东海区,冬季冷(暖)异常的洋面上是异常低压(高压),对流层中层是太平洋—北美型(Pacific-North American Pattern,PNA)遥相关的正(负)位相;当东部风暴轴增强(减弱)时,同期冬季黑潮区海温偏暖(偏冷),对流层中层表现为西太平洋型(West Pacific Pattern,WP)遥相关的正(负)位相;当东部风暴轴呈现西北—东南+-+(-+-)相间三极子的分布时,同期冬季巴布亚新几内亚附近海温异常偏暖(冷),夏威夷附近海温异常偏冷(暖),冬季冷(暖)异常的洋面上是异常低(高)压,对流层中层表现出类似PNA正(负)位相。EOF分解各模态所对应时间系数与阿留申低压(Aleutian Low,AL)指数、PNA指数、Nino3指数、WP指数、黑潮海温(Kuroshio Current,KC)指数之间存在显著的相关,这些证明了东部风暴轴与同期大气环流及SST异常之间的联系。
文摘Climalological features of mid-latitude blocking occurring over the North Pacific Ocean during 52 winters (December to February) of 1948/1949-1999/2000 are statistically analyzed based on NCEP/ NCAR reanalysis data. Significant interannual variation with a period of about 3-7 years as well as decadal variability is found by wavelet analysis and power spectrum analysis. A decreasing trend of the 2-7 year bandscale-averaged variance occurs throughout the 52 years and an abrupt shift from a higher state to a lower state during the 1970s is also found, which suggests an interdecadal variation of the North Pacific blocking. The possible relationship between the variability of blocking and sea surface temperature (SST), storm tracks and teleconnection are shown using composite analysis. In strong blocking anomaly winter (SBW), the geopotential height anomaly at 500 hPa exhibits a typical PNA (Pacific-North American)-like wave-train pattern in the North Pacific. The storm tracks, representing the activity of transient eddies, extend northeastward to the western coast of North America along the mid latitudes of about 40°-50°N, with the SST anomaly exhibiting a Pacific decadal oscillation (PDO) mode at mid-latitude and a La Niña-like pattern along the equator. Contrasting features appear in weak blocking anomaly winter (WBW).
文摘基于中尺度大气模式WRF(Weather Research and Forecasting Model),首先对2007年3次船舶辐射通量观测进行模拟,以检验WRF对长波和短波辐射通量的模拟能力,结果表明使用中国近海海洋环境数值预报系统环流模式POM(Princeton Ocean Model)模拟的高时空分辨率的海洋表层温度能够显著改进短波辐射通量的模拟,而对长波辐射通量模拟的改进不明显。然后,将业务化运行的中国近海海洋环境数值预报系统后报的逐时海洋表面温度(SST)作为WRF底边界条件,对2008年15号强台风"蔷薇"(Jangmi)过程进行了数值后报试验。结果表明,与使用NCEP/NCAR的SST试验后报的台风中心位置偏差相比,使用高时空分辨率的SST能够较为显著地改善"蔷薇"的路径模拟,台风中心位置模拟偏差减少11%,尤其在台风减弱阶段,台风中心位置模拟偏差减少37%。台风强度在台风发展的不同阶段对下垫面SST的变化敏感性不同。台风路径附近的海表面温度下降会导致海洋向大气输送的热量减少从而减弱台风强度。
