基于中国气象局气象业务观测站、青藏高原大气科学试验站及中国科学院野外试验站多源辐射观测数据,经过质量控制和拼接整合,形成1993年以来青藏高原多源气象辐射基本要素逐小时曝辐量整合数据集(Integrated of Multi-source Radiation D...基于中国气象局气象业务观测站、青藏高原大气科学试验站及中国科学院野外试验站多源辐射观测数据,经过质量控制和拼接整合,形成1993年以来青藏高原多源气象辐射基本要素逐小时曝辐量整合数据集(Integrated of Multi-source Radiation Data over Qinghai-Tibet Plateau,IRDQTP)。各辐射要素实有率均超过99.4%,光合有效辐射正确率低于76%,其他辐射要素正确率超过96.7%。相同或相近观测站址的大气科学或野外试验站(试验站)与气象业务观测站(业务站)向下短波辐射R>0.88,阿里相同站址两种来源数据对比Mbias(RMSE)为-0.006(0.141)MJ·m^(-2)·h^(-1),99.8%的偏差分布在±1.0 MJ·m^(-2)·h^(-1),那曲相近站址两种来源数据对比Mbias(RMSE)为-0.028(0.615)MJ·m^(-2)·h^(-1),84.6%的偏差分布在±1.0 MJ·m^(-2)·h^(-1)。试验站和业务站数据差异呈现明显的季节变化和日变化规律,秋冬季节较小,夏季较大,日出时段(日落时段)随着向下短波辐射强度快速升高(快速降低),差异逐渐变大,当向下短波辐射变化率达到最大时,差异也达到最大。向下短波辐射和净全辐射分布具有明显的日变化特征,春秋季节向下短波辐射、净全辐射均在12:00(地方时,下同)达到最大,夏季和冬季在13:00达到最大。受气候条件和地形因素影响,向下短波辐射和净全辐射分布具有明显的空间变化特征,向下短波辐射自西向东呈现逐渐减少的分布形态,净全辐射自西向东呈现“低-高-低”的分布形态。展开更多
本文针对国家气象信息中心(Chinese National Meteorological Information Center, NMIC)整理的“中国中东部百年均一化气温月值序列(V1.0)”中的中国东部16个站点1916.01~2015.12共100年的月平均气温数据进行分析,结合去趋势波动分析法...本文针对国家气象信息中心(Chinese National Meteorological Information Center, NMIC)整理的“中国中东部百年均一化气温月值序列(V1.0)”中的中国东部16个站点1916.01~2015.12共100年的月平均气温数据进行分析,结合去趋势波动分析法(Detrended Fluctuation Analysis, DFA)研究了百年温度序列的长程相关性,揭示了该地区气候系统的记忆性特征及其年代际演变规律。文中首先分析比较了东部16个百年温度序列的常规统计量特征,发现近百年月温度序列中呈现的趋势变化,由中国北部到南方地区总体减弱,其主要原因在于北方地区近百年月温度序列整体平稳增长,而南方大部分台站基本是在1980s后才出现显著增温趋势。进一步,本文计算了16个台站百年尺度的温度序列标度指数,结果表明中国东部各个台站月温度序列标度指数范围在0.62~0.85之间,都存在一定长程相关性,其中东北和长江中下游区域台站温度序列长程相关性较强,南方地区长程相关性相对较弱。在此基础上,选取了50年时间窗口以10年为步长滑动计算温度序列标度指数,研究发现在100年内中国东部16站点的温度序列长程相关性存在转折,大部分站点的标度指数在前70年(1916~1986年)相对较为稳定,但是进入1980s,其长程相关性明显减弱,直至最近50年(1976~2015),标度指数又出现整体增长趋势。该项研究结果可以为气候变化检测评估提供科学依据和支撑。展开更多
Based on nonlinear prediction and information theory, vertical heterogeneity of predictability and information loss rate in geopotential height field are obtained over the Northern Hemisphere. On a seasonal-to-interan...Based on nonlinear prediction and information theory, vertical heterogeneity of predictability and information loss rate in geopotential height field are obtained over the Northern Hemisphere. On a seasonal-to-interannual time scale, the predictability is low in the lower troposphere and high in the mid-upper troposphere. However, within mid-upper troposphere over the subtropics ocean area, there is a relatively poor predictability. These conclusions also fit the seasonal time scale. Moving to the interannual time scale, the predictability becomes high in the lower troposphere and low in the mid-upper troposphere, contrary to the former case. On the whole the interannual trend is more predictable than the seasonal trend. The average information loss rate is low over the mid-east Pacific, west of North America, Atlantic and Eurasia, and the atmosphere over other places has a relatively high information loss rate on all-time scales. Two channels are found steadily over the Pacific Ocean and Atlantic Ocean in subtropics. There are also unstable channels. The four- season influence on predictability and information communication are studied. The predictability is low, no matter which season data are removed and each season plays an important role in the existence of the channels, except for the winter. The predictability and teleconnections are paramount issues in atmospheric science, and the teleconnections may be established by communication channels. So, this work is interesting since it reveals the vertical structure of predictability distribution, channel locations, and the contributions of different time scales to them and their variations under different seasons.展开更多
The uneven spatial distribution of stations providing precipitable water vapor(PWV)observations in China hinders the effective use of these data in assimilation,nowcasting,and prediction.In this study,we proposed a co...The uneven spatial distribution of stations providing precipitable water vapor(PWV)observations in China hinders the effective use of these data in assimilation,nowcasting,and prediction.In this study,we proposed a complex network framework for exploring the topological structure and the collective behavior of PWV in the mainland of China.We used the Pearson correlation coefficient and transfer entropy to measure the linear and nonlinear relationships of PWV amongst different stations and to set up the undirected and directed complex networks,respectively.Our findings revealed the statistical and geographical distribution of the variables influencing PWV networks and identified the vapor information source and sink stations.Specifically,the findings showed that the statistical and spatial distributions of the undirected and directed complex vapor networks in terms of degree and distance were similar to each other(the common interaction mode for vapor stations and their locations).The betweenness results displayed different features.The largest betweenness ratio for directed networks tended to be larger than that of the undirected networks,implying that the transfer of directed PWV networks was more efficient than that of the undirected networks.The findings of this study are heuristic and will be useful for constructing the best strategy for the PWV data in applications such as vapor observational networks design and precipitation prediction.展开更多
We propose a quantitative network description on the tunction ot uniqueness in a competition system. statistical parameters, competition ability and uniqueness are defined, and their relationship in ordinary cases is ...We propose a quantitative network description on the tunction ot uniqueness in a competition system. statistical parameters, competition ability and uniqueness are defined, and their relationship in ordinary cases is analytically discussed. The competition between Chinese regional universities is taken as an example. The empirical investigation results show that the uniqueness of a university is really important in competition. Also, uniqueness is very helpful in the promotion of the university overall quality.展开更多
文摘基于中国气象局气象业务观测站、青藏高原大气科学试验站及中国科学院野外试验站多源辐射观测数据,经过质量控制和拼接整合,形成1993年以来青藏高原多源气象辐射基本要素逐小时曝辐量整合数据集(Integrated of Multi-source Radiation Data over Qinghai-Tibet Plateau,IRDQTP)。各辐射要素实有率均超过99.4%,光合有效辐射正确率低于76%,其他辐射要素正确率超过96.7%。相同或相近观测站址的大气科学或野外试验站(试验站)与气象业务观测站(业务站)向下短波辐射R>0.88,阿里相同站址两种来源数据对比Mbias(RMSE)为-0.006(0.141)MJ·m^(-2)·h^(-1),99.8%的偏差分布在±1.0 MJ·m^(-2)·h^(-1),那曲相近站址两种来源数据对比Mbias(RMSE)为-0.028(0.615)MJ·m^(-2)·h^(-1),84.6%的偏差分布在±1.0 MJ·m^(-2)·h^(-1)。试验站和业务站数据差异呈现明显的季节变化和日变化规律,秋冬季节较小,夏季较大,日出时段(日落时段)随着向下短波辐射强度快速升高(快速降低),差异逐渐变大,当向下短波辐射变化率达到最大时,差异也达到最大。向下短波辐射和净全辐射分布具有明显的日变化特征,春秋季节向下短波辐射、净全辐射均在12:00(地方时,下同)达到最大,夏季和冬季在13:00达到最大。受气候条件和地形因素影响,向下短波辐射和净全辐射分布具有明显的空间变化特征,向下短波辐射自西向东呈现逐渐减少的分布形态,净全辐射自西向东呈现“低-高-低”的分布形态。
文摘本文针对国家气象信息中心(Chinese National Meteorological Information Center, NMIC)整理的“中国中东部百年均一化气温月值序列(V1.0)”中的中国东部16个站点1916.01~2015.12共100年的月平均气温数据进行分析,结合去趋势波动分析法(Detrended Fluctuation Analysis, DFA)研究了百年温度序列的长程相关性,揭示了该地区气候系统的记忆性特征及其年代际演变规律。文中首先分析比较了东部16个百年温度序列的常规统计量特征,发现近百年月温度序列中呈现的趋势变化,由中国北部到南方地区总体减弱,其主要原因在于北方地区近百年月温度序列整体平稳增长,而南方大部分台站基本是在1980s后才出现显著增温趋势。进一步,本文计算了16个台站百年尺度的温度序列标度指数,结果表明中国东部各个台站月温度序列标度指数范围在0.62~0.85之间,都存在一定长程相关性,其中东北和长江中下游区域台站温度序列长程相关性较强,南方地区长程相关性相对较弱。在此基础上,选取了50年时间窗口以10年为步长滑动计算温度序列标度指数,研究发现在100年内中国东部16站点的温度序列长程相关性存在转折,大部分站点的标度指数在前70年(1916~1986年)相对较为稳定,但是进入1980s,其长程相关性明显减弱,直至最近50年(1976~2015),标度指数又出现整体增长趋势。该项研究结果可以为气候变化检测评估提供科学依据和支撑。
基金Project supported by the National Key Basic Research and Development Program,China (Grant Nos.2012CB955902 and 2013CB430204)the National Natural Science Foundation of China (Grant Nos.41305059,41305100,41275096 and 41105070)
文摘Based on nonlinear prediction and information theory, vertical heterogeneity of predictability and information loss rate in geopotential height field are obtained over the Northern Hemisphere. On a seasonal-to-interannual time scale, the predictability is low in the lower troposphere and high in the mid-upper troposphere. However, within mid-upper troposphere over the subtropics ocean area, there is a relatively poor predictability. These conclusions also fit the seasonal time scale. Moving to the interannual time scale, the predictability becomes high in the lower troposphere and low in the mid-upper troposphere, contrary to the former case. On the whole the interannual trend is more predictable than the seasonal trend. The average information loss rate is low over the mid-east Pacific, west of North America, Atlantic and Eurasia, and the atmosphere over other places has a relatively high information loss rate on all-time scales. Two channels are found steadily over the Pacific Ocean and Atlantic Ocean in subtropics. There are also unstable channels. The four- season influence on predictability and information communication are studied. The predictability is low, no matter which season data are removed and each season plays an important role in the existence of the channels, except for the winter. The predictability and teleconnections are paramount issues in atmospheric science, and the teleconnections may be established by communication channels. So, this work is interesting since it reveals the vertical structure of predictability distribution, channel locations, and the contributions of different time scales to them and their variations under different seasons.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41775081,41975100,41901016,and 41875100)the Innovation Project of the China Meteorological Administration(Grant No.CXFZ2021Z034)the National Key Research and Development Program of China(Grant No.2018YFC1507702)。
文摘The uneven spatial distribution of stations providing precipitable water vapor(PWV)observations in China hinders the effective use of these data in assimilation,nowcasting,and prediction.In this study,we proposed a complex network framework for exploring the topological structure and the collective behavior of PWV in the mainland of China.We used the Pearson correlation coefficient and transfer entropy to measure the linear and nonlinear relationships of PWV amongst different stations and to set up the undirected and directed complex networks,respectively.Our findings revealed the statistical and geographical distribution of the variables influencing PWV networks and identified the vapor information source and sink stations.Specifically,the findings showed that the statistical and spatial distributions of the undirected and directed complex vapor networks in terms of degree and distance were similar to each other(the common interaction mode for vapor stations and their locations).The betweenness results displayed different features.The largest betweenness ratio for directed networks tended to be larger than that of the undirected networks,implying that the transfer of directed PWV networks was more efficient than that of the undirected networks.The findings of this study are heuristic and will be useful for constructing the best strategy for the PWV data in applications such as vapor observational networks design and precipitation prediction.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10635040 and 70671089.
文摘We propose a quantitative network description on the tunction ot uniqueness in a competition system. statistical parameters, competition ability and uniqueness are defined, and their relationship in ordinary cases is analytically discussed. The competition between Chinese regional universities is taken as an example. The empirical investigation results show that the uniqueness of a university is really important in competition. Also, uniqueness is very helpful in the promotion of the university overall quality.
