The seasonal variability and spatial distribution of precipitation are the main cause of flood and drought events. The study of spatial distribution and temporal trend of precipitation in river basins has been paid mo...The seasonal variability and spatial distribution of precipitation are the main cause of flood and drought events. The study of spatial distribution and temporal trend of precipitation in river basins has been paid more and more attention. However, in China, the precipitation data are measured by weather stations （WS） of China Meteorological Administration and hydrological rain gauges （RG） of national and local hydrology bureau. The WS data usually have long record with fewer stations, while the RG data usually have short record with more stations. The consistency and correlation of these two data sets have not been well understood. In this paper, the precipitation data from 30 weather stations for 1958-2007 and 248 rain gauges for 1995-2004 in the Haihe River basin are examined and compared using linear regression, 5-year moving average, Mann-Kendall trend analysis, Kolmogorov-Smirnov test, Z test and F test methods. The results show that the annual precipitation from both WS and RG records are normally distributed with minor difference in the mean value and variance. It is statistically feasible to extend the precipitation of RG by WS data sets. Using the extended precipitation data, the detailed spatial distribution of the annual and seasonal precipitation amounts as well as their temporal trends are calculated and mapped. The various distribution maps produced in the study show that for the whole basin the precipitation of 1958-2007 has been decreasing except for spring season. The decline trend is significant in summer, and this trend is stronger after the 1980s. The annual and seasonal precipitation amounts and changing trends are different in different regions and seasons. The precipitation is decreasing from south to north, from coastal zone to inland area.展开更多
Earthquakes are caused by the failure of faults, driven by tectonic stress build-up in the Earth＇s crust. To study the earthquake preparation process and assess regional earthquake potentials, it is vitally important...Earthquakes are caused by the failure of faults, driven by tectonic stress build-up in the Earth＇s crust. To study the earthquake preparation process and assess regional earthquake potentials, it is vitally important to understand the crustal stress evolution process and identify its change in pattern associated with the seismogenic process. In this study we investigate the focal mechanism orientations of earthquakes in southern California from 1982 to 1999, basing on a focal mechanism catalog from Hauksson. We find that for the two large earthquakes occurred in southern California, the 1992 Mw7.3 Landers and the 1999 Mw7.1 Hector Mine, the orientations of focal mechanisms near the coming earthquake tend to converge to the stress direction promoting the rupture of the coming earthquake and align with its focal mechanism about half-year before its occurrence, suggesting that the tectonic stress field gets more organized in favor of the rupture of the event pre-seismically. The degree of stress convergence is measured by the orientation angle RMS （root mean square） between the preshocks＇ focal mechanisms and the focal mechanism of the large event studied, and its time series recorded the stress convergence process. The degree of anomalies, measured by the F-tests, indicates that the convergence of stress orientations become significant at 90% confidence about half-year prior to both the Landers and Hector Mine quakes, and it becomes even more prominent at 99% confidence right before the occurrences. Our study may be of significance for assessment of regional seismic potentials.展开更多
The characteristics of Mann-Kendall Rank Statistics and its applications in detecting abrupt change of climate have been described.At the same time,a new method is put forward to detect the abrupt change in variance.
目的建立了一种反相高效液相色谱-紫外检测法用于复方磺胺嘧啶滴鼻液中磺胺嘧啶和盐酸麻黄碱的含量测定。方法色谱柱为Zorbax Bonus RP C18（150mm×4．6mm，5μm），流动相为0．050mol·L^-1磷酸二氢钾溶液（含0．5％三乙胺，...目的建立了一种反相高效液相色谱-紫外检测法用于复方磺胺嘧啶滴鼻液中磺胺嘧啶和盐酸麻黄碱的含量测定。方法色谱柱为Zorbax Bonus RP C18（150mm×4．6mm，5μm），流动相为0．050mol·L^-1磷酸二氢钾溶液（含0．5％三乙胺，用磷酸调节pH值至2．3）-甲醇（80：20），盐酸麻黄碱的检测波长为216nm，磺胺嘧啶为265nm。结果磺胺嘧啶和盐酸麻黄碱分别在3．3～33．6μg·mL^-1，6．0～60．75μg·mL^-1峰面积和浓度呈线性关系，相关系数均为0．9996，磺胺嘧啶和盐酸麻黄碱的平均回收率分别为101．1%和100．0％。以文献方法作为参考方法，通过F-检验核对了定量方法的精密性，磺胺嘧啶和盐酸麻黄碱的两方法平均偏差的比值均接近于1．0。结论该分析方法准确、稳定，可用于复方磺胺嘧啶滴鼻液的质量控制。展开更多
基金National Basic Research Program of China, No.2010CB428406 The Key Knowledge Innovation Project of the CAS, No.KZCX2-YW-126 Key Project of National Natural Science Foundation of China, No.40730632
文摘The seasonal variability and spatial distribution of precipitation are the main cause of flood and drought events. The study of spatial distribution and temporal trend of precipitation in river basins has been paid more and more attention. However, in China, the precipitation data are measured by weather stations （WS） of China Meteorological Administration and hydrological rain gauges （RG） of national and local hydrology bureau. The WS data usually have long record with fewer stations, while the RG data usually have short record with more stations. The consistency and correlation of these two data sets have not been well understood. In this paper, the precipitation data from 30 weather stations for 1958-2007 and 248 rain gauges for 1995-2004 in the Haihe River basin are examined and compared using linear regression, 5-year moving average, Mann-Kendall trend analysis, Kolmogorov-Smirnov test, Z test and F test methods. The results show that the annual precipitation from both WS and RG records are normally distributed with minor difference in the mean value and variance. It is statistically feasible to extend the precipitation of RG by WS data sets. Using the extended precipitation data, the detailed spatial distribution of the annual and seasonal precipitation amounts as well as their temporal trends are calculated and mapped. The various distribution maps produced in the study show that for the whole basin the precipitation of 1958-2007 has been decreasing except for spring season. The decline trend is significant in summer, and this trend is stronger after the 1980s. The annual and seasonal precipitation amounts and changing trends are different in different regions and seasons. The precipitation is decreasing from south to north, from coastal zone to inland area.
基金supported by the National Natural Science Foundation of China(40874022)Public Utility Research Project(200808053)
文摘Earthquakes are caused by the failure of faults, driven by tectonic stress build-up in the Earth＇s crust. To study the earthquake preparation process and assess regional earthquake potentials, it is vitally important to understand the crustal stress evolution process and identify its change in pattern associated with the seismogenic process. In this study we investigate the focal mechanism orientations of earthquakes in southern California from 1982 to 1999, basing on a focal mechanism catalog from Hauksson. We find that for the two large earthquakes occurred in southern California, the 1992 Mw7.3 Landers and the 1999 Mw7.1 Hector Mine, the orientations of focal mechanisms near the coming earthquake tend to converge to the stress direction promoting the rupture of the coming earthquake and align with its focal mechanism about half-year before its occurrence, suggesting that the tectonic stress field gets more organized in favor of the rupture of the event pre-seismically. The degree of stress convergence is measured by the orientation angle RMS （root mean square） between the preshocks＇ focal mechanisms and the focal mechanism of the large event studied, and its time series recorded the stress convergence process. The degree of anomalies, measured by the F-tests, indicates that the convergence of stress orientations become significant at 90% confidence about half-year prior to both the Landers and Hector Mine quakes, and it becomes even more prominent at 99% confidence right before the occurrences. Our study may be of significance for assessment of regional seismic potentials.
文摘The characteristics of Mann-Kendall Rank Statistics and its applications in detecting abrupt change of climate have been described.At the same time,a new method is put forward to detect the abrupt change in variance.
文摘目的建立了一种反相高效液相色谱-紫外检测法用于复方磺胺嘧啶滴鼻液中磺胺嘧啶和盐酸麻黄碱的含量测定。方法色谱柱为Zorbax Bonus RP C18（150mm×4．6mm，5μm），流动相为0．050mol·L^-1磷酸二氢钾溶液（含0．5％三乙胺，用磷酸调节pH值至2．3）-甲醇（80：20），盐酸麻黄碱的检测波长为216nm，磺胺嘧啶为265nm。结果磺胺嘧啶和盐酸麻黄碱分别在3．3～33．6μg·mL^-1，6．0～60．75μg·mL^-1峰面积和浓度呈线性关系，相关系数均为0．9996，磺胺嘧啶和盐酸麻黄碱的平均回收率分别为101．1%和100．0％。以文献方法作为参考方法，通过F-检验核对了定量方法的精密性，磺胺嘧啶和盐酸麻黄碱的两方法平均偏差的比值均接近于1．0。结论该分析方法准确、稳定，可用于复方磺胺嘧啶滴鼻液的质量控制。
