我于2000年7月被录取为河北大学教育史专业博士研究生，同时接到英国西敏斯特大学（University of Westminster）的邀请函，于该年10月以访问学者身份赴英国进行为期一年的进修。根据导师的建议，出国学习之前便确定了以英国教育史为研...我于2000年7月被录取为河北大学教育史专业博士研究生，同时接到英国西敏斯特大学（University of Westminster）的邀请函，于该年10月以访问学者身份赴英国进行为期一年的进修。根据导师的建议，出国学习之前便确定了以英国教育史为研究方向。非常庆幸的是，在英期间，恰逢导师贺国庆教授在伦敦大学教育学院（Institute of Education，University of London，IOE）做高级访问学者。展开更多
We have developed a 202-year tree-ring width chronology of Shensi fir(Abies chensiensis) growing in an open canopy forest at the treeline of the eastern Qinling Mountains. Climate response analyses revealed that the r...We have developed a 202-year tree-ring width chronology of Shensi fir(Abies chensiensis) growing in an open canopy forest at the treeline of the eastern Qinling Mountains. Climate response analyses revealed that the ring width of Shensi fir trees is primarily controlled by the range of temperature from February–June. The regression model that we used for statistical temperature reconstruction passed the leave-one-out cross-validation used in dendroclimatology, resulting in a quality-controlled February–June reconstruction for the eastern Qinling Mountains. The model accounts for 36.7% of the instrumental temperature variance during the period of 1960–2012. Warm springs and early summers occurred during AD 1870–1873, 1909–1914, 1927–1958 and 1997–2012, while the periods of AD 1874–1908, 1915–1926 and 1959–1996 were relatively cold. Spatial climate correlation analyses with gridded land surface data revealed that our temperature reconstruction contains a strong regional temperature signal for central China. The linkages of ourtemperature reconstruction with sea surface temperature in the Atlantic and Pacific oceans suggest the connection of regional temperature variations to large-scale ocean–atmosphere–land circulation. Preliminary analysis of links between large-scale climatic variation and the temperature reconstruction also shows that there is a relationship between extremes in spring and early summer temperature and anomalous atmospheric circulation in the Qinling Mountains. Overall, our study provides reliable information for the research of past temperature variability in the Qinling Mountains, China.展开更多
The sensitive regions of conditional nonlinear optimal perturbations (CNOPs) and the first singular vector (FSV) for a northwest Pacific typhoon case are reported in this paper. A large number of probes have been desi...The sensitive regions of conditional nonlinear optimal perturbations (CNOPs) and the first singular vector (FSV) for a northwest Pacific typhoon case are reported in this paper. A large number of probes have been designed in the above regions and the ensemble transform Kalman filter (ETKF) techniques are utilized to examine which approach can locate more appropriate regions for typhoon adaptive observations. The results show that, in general, the majority of the probes in the sensitive regions of CNOPs can reduce more forecast error variance than the probes in the sensitive regions of FSV. This implies that adaptive observations in the sensitive regions of CNOPs are more effective than in the sensitive regions of FSV. Furthermore, the reduction of the forecast error variance obtained by the best probe identified by CNOPs is twice the reduction of the forecast error variance obtained by FSV. This implies that dropping sondes, which is the best probe identified by CNOPs, can improve the forecast more than the best probe identified by FSV. These results indicate that the sensitive regions identified by CNOPs are more appropriate for adaptive observations than those identified by FSV.展开更多
文摘我于2000年7月被录取为河北大学教育史专业博士研究生，同时接到英国西敏斯特大学（University of Westminster）的邀请函，于该年10月以访问学者身份赴英国进行为期一年的进修。根据导师的建议，出国学习之前便确定了以英国教育史为研究方向。非常庆幸的是，在英期间，恰逢导师贺国庆教授在伦敦大学教育学院（Institute of Education，University of London，IOE）做高级访问学者。
基金supported by the Basic Research Operating Expenses of the Central-level Non-profit Research Institutes of China (IDM201105)the Open Foundation of MOE Key Laboratory of Western China's Environmental System, Lanzhou Universitythe Fundamental Research Funds for the Central Universities (lzujbky-2011-t02)
文摘We have developed a 202-year tree-ring width chronology of Shensi fir(Abies chensiensis) growing in an open canopy forest at the treeline of the eastern Qinling Mountains. Climate response analyses revealed that the ring width of Shensi fir trees is primarily controlled by the range of temperature from February–June. The regression model that we used for statistical temperature reconstruction passed the leave-one-out cross-validation used in dendroclimatology, resulting in a quality-controlled February–June reconstruction for the eastern Qinling Mountains. The model accounts for 36.7% of the instrumental temperature variance during the period of 1960–2012. Warm springs and early summers occurred during AD 1870–1873, 1909–1914, 1927–1958 and 1997–2012, while the periods of AD 1874–1908, 1915–1926 and 1959–1996 were relatively cold. Spatial climate correlation analyses with gridded land surface data revealed that our temperature reconstruction contains a strong regional temperature signal for central China. The linkages of ourtemperature reconstruction with sea surface temperature in the Atlantic and Pacific oceans suggest the connection of regional temperature variations to large-scale ocean–atmosphere–land circulation. Preliminary analysis of links between large-scale climatic variation and the temperature reconstruction also shows that there is a relationship between extremes in spring and early summer temperature and anomalous atmospheric circulation in the Qinling Mountains. Overall, our study provides reliable information for the research of past temperature variability in the Qinling Mountains, China.
基金jointly sponsored by the National Natural Science Foundation of China (Grant Nos. 40830955 and 40821092)the China Meteorological Administration (Grant No. GYHY200906009)
文摘The sensitive regions of conditional nonlinear optimal perturbations (CNOPs) and the first singular vector (FSV) for a northwest Pacific typhoon case are reported in this paper. A large number of probes have been designed in the above regions and the ensemble transform Kalman filter (ETKF) techniques are utilized to examine which approach can locate more appropriate regions for typhoon adaptive observations. The results show that, in general, the majority of the probes in the sensitive regions of CNOPs can reduce more forecast error variance than the probes in the sensitive regions of FSV. This implies that adaptive observations in the sensitive regions of CNOPs are more effective than in the sensitive regions of FSV. Furthermore, the reduction of the forecast error variance obtained by the best probe identified by CNOPs is twice the reduction of the forecast error variance obtained by FSV. This implies that dropping sondes, which is the best probe identified by CNOPs, can improve the forecast more than the best probe identified by FSV. These results indicate that the sensitive regions identified by CNOPs are more appropriate for adaptive observations than those identified by FSV.
