With the warm/cold phases of the El Ni o and Southern Oscillation (ENSO) as a background, the impacts of monthly variation in the Arctic Oscillation (AO) on the winter climate anomalies in East Asia are studied with t...With the warm/cold phases of the El Ni o and Southern Oscillation (ENSO) as a background, the impacts of monthly variation in the Arctic Oscillation (AO) on the winter climate anomalies in East Asia are studied with the NCEP/DOE Reanalysis 2 data and the Chinese station data regarding temperature and rainfall. The combined effects of ENSO and the AO indicate that the winter climate anomalies are mainly influenced by the AO in northern China and the ENSO in southern China, when an El Ni o couples with a negative AO month or a La Ni a couples with a positive AO month. These climate anomalies in China are consistent with the mechanisms proposed in previous studies. However, most of China presents a different pattern of climate anomalies if an El Ni o couples with a positive AO month or a La Ni a couples with a negative AO month, with the exception of the temperature anomalies in northern China, which are still affected dominantly by the AO. Further analysis suggests that the causes are attributed to the differences in both the stratosphere-troposphere interaction and the extratropics-tropics interaction. In the former cases, zonal symmetric circulation prevails in the winter and the extratropics-tropics interaction is weakened. Thus, the influences of the ENSO and the AO on the East Asian climate mainly present linear combination effects. On the contrary, an annular mode of atmospheric circulation is not favored in the latter cases and the extratropics-tropics interaction is strong. Hence, the combined effects of the ENSO and the AO on the winter climate in East Asia present nonlinear characteristics.展开更多
Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） we...Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） were compared with non-pumped near-surface temperatures（NSTs） obtained from Argo profiling floats over the global oceans. Factors that might cause temperature differences were examined, including wind speed, columnar water vapor, liquid cloud water, and geographic location. The results show that both TMI and AMSR-E SSTs are highly correlated with the Argo NSTs; however, at low wind speeds, they are on average warmer than the Argo NSTs. The TMI performs slightly better than the AMSR-E at low wind speeds, whereas the TMI SST retrievals might be poorly calibrated at high wind speeds. The temperature differences indicate a warm bias of the TMI/AMSR-E when columnar water vapor is low, which can indicate that neither TMI nor AMSR-E SSTs are well calibrated at high latitudes. The SST in the Kuroshio Extension region has higher variability than in the Kuroshio region. The variability of the temperature difference between the satellite-retrieved SSTs and the Argo NSTs is lower in the Kuroshio Extension during spring. At low wind speeds, neither TMI nor AMSR-E SSTs are well calibrated, although the TMI performs better than the AMSR-E.展开更多
Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of cl...Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of climate change,especially sea-level rise, and human activity, mangrove forests around the world have faced degradation, against which the reconstruction of the historical development of mangrove forests using an effective indicator has been regarded as a necessary strategy for designing a predictable model. As the primary product of mangrove forest, it is reasonable that the content of leaf fragments of mangrove(CLFM) buried in sediments in the form of sub-fossils potentially has the same indicative function for the development of mangrove forests as that of widely-used mangrove pollen. In this study, the leaf fragments of mangrove in two sediment cores(YLW02 and YLW03) drilled in the Yingluo Bay in Guangxi, Southwest China were picked out and weighted for calculation of CLFM, which was used as an indicator of mangrove development after examination of parallelism and a statistical correlation of the CLFM with the concentration of mangrove pollen. The results clearly show that the vertical distribution of the CLFM for the core taken from the landward margin of mangrove forests(YLW03) only parallels that of the local mangrove species(Rhizophora. stylosa) with a significantly positive correlation(R=0.56, P=0.05), while the vertical distribution of the CLFM for the core taken from the interface between seaward margin of mangrove forest and the trunk of tidal creeks of the bay(YLW02) parallels the summed concentration of mangrove pollen(SCMP) with a more positive correlation than that of YLW03(R=0.85, P=0.01), indicating that the trunk outlet of tidal creeks must have been the site where mangrove production gathered from the overall forest rather than from local production. The variations in the CLFM of both cores indicate that overall the mangrove forests in the Yingluo Bay have increasingly flourished ove展开更多
改进的奇异值分解(advanced singular value decomposition,ASVD)方法,是对经过空间均匀化订正的格、站点网资料的奇异值分解(singular value decomposition,SVD)方法。根据奇异向量与经验正交函数(empirical orthogonal function,EOF)...改进的奇异值分解(advanced singular value decomposition,ASVD)方法,是对经过空间均匀化订正的格、站点网资料的奇异值分解(singular value decomposition,SVD)方法。根据奇异向量与经验正交函数(empirical orthogonal function,EOF)的关系,给出了格、站点网资料SVD方法中均匀化订正的方法,进而得到了改进的奇异值分解(ASVD)方法。将ASVD方法、SVD方法用于中国60a(1951—2010年)160站冬季气温、降水同期相关系数矩阵C的分析,结果表明:ASVD方法的前4个主要模态的模方拟合率和累积模方拟合率均明显高于SVD方法;ASVD方法前两个奇异向量典型场图上高绝对值区与C模方图上高值区的关系明显较SVD方法合理。由此论证了SVD方法中资料均匀化订正的必要性,验证了实际分析中ASVD方法的效果。展开更多
基金supported by the National Basic Research Program of China (2009CB421405)the National Natural Science Foundation of China (41025017 and 41230527)
文摘With the warm/cold phases of the El Ni o and Southern Oscillation (ENSO) as a background, the impacts of monthly variation in the Arctic Oscillation (AO) on the winter climate anomalies in East Asia are studied with the NCEP/DOE Reanalysis 2 data and the Chinese station data regarding temperature and rainfall. The combined effects of ENSO and the AO indicate that the winter climate anomalies are mainly influenced by the AO in northern China and the ENSO in southern China, when an El Ni o couples with a negative AO month or a La Ni a couples with a positive AO month. These climate anomalies in China are consistent with the mechanisms proposed in previous studies. However, most of China presents a different pattern of climate anomalies if an El Ni o couples with a positive AO month or a La Ni a couples with a negative AO month, with the exception of the temperature anomalies in northern China, which are still affected dominantly by the AO. Further analysis suggests that the causes are attributed to the differences in both the stratosphere-troposphere interaction and the extratropics-tropics interaction. In the former cases, zonal symmetric circulation prevails in the winter and the extratropics-tropics interaction is weakened. Thus, the influences of the ENSO and the AO on the East Asian climate mainly present linear combination effects. On the contrary, an annular mode of atmospheric circulation is not favored in the latter cases and the extratropics-tropics interaction is strong. Hence, the combined effects of the ENSO and the AO on the winter climate in East Asia present nonlinear characteristics.
基金The National Basic Research Program(973 Program)of China under contract No.2013CB430301the National Natural Science Foundation of China under contract Nos 41440039,41206022 and 41406022the Public Science and Technology Research Funds Projects of Ocean under contract No.201305032
文摘Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） were compared with non-pumped near-surface temperatures（NSTs） obtained from Argo profiling floats over the global oceans. Factors that might cause temperature differences were examined, including wind speed, columnar water vapor, liquid cloud water, and geographic location. The results show that both TMI and AMSR-E SSTs are highly correlated with the Argo NSTs; however, at low wind speeds, they are on average warmer than the Argo NSTs. The TMI performs slightly better than the AMSR-E at low wind speeds, whereas the TMI SST retrievals might be poorly calibrated at high wind speeds. The temperature differences indicate a warm bias of the TMI/AMSR-E when columnar water vapor is low, which can indicate that neither TMI nor AMSR-E SSTs are well calibrated at high latitudes. The SST in the Kuroshio Extension region has higher variability than in the Kuroshio region. The variability of the temperature difference between the satellite-retrieved SSTs and the Argo NSTs is lower in the Kuroshio Extension during spring. At low wind speeds, neither TMI nor AMSR-E SSTs are well calibrated, although the TMI performs better than the AMSR-E.
基金The National Natural Science Foundation of China under contract Nos 41376075 and 41576061
文摘Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of climate change,especially sea-level rise, and human activity, mangrove forests around the world have faced degradation, against which the reconstruction of the historical development of mangrove forests using an effective indicator has been regarded as a necessary strategy for designing a predictable model. As the primary product of mangrove forest, it is reasonable that the content of leaf fragments of mangrove(CLFM) buried in sediments in the form of sub-fossils potentially has the same indicative function for the development of mangrove forests as that of widely-used mangrove pollen. In this study, the leaf fragments of mangrove in two sediment cores(YLW02 and YLW03) drilled in the Yingluo Bay in Guangxi, Southwest China were picked out and weighted for calculation of CLFM, which was used as an indicator of mangrove development after examination of parallelism and a statistical correlation of the CLFM with the concentration of mangrove pollen. The results clearly show that the vertical distribution of the CLFM for the core taken from the landward margin of mangrove forests(YLW03) only parallels that of the local mangrove species(Rhizophora. stylosa) with a significantly positive correlation(R=0.56, P=0.05), while the vertical distribution of the CLFM for the core taken from the interface between seaward margin of mangrove forest and the trunk of tidal creeks of the bay(YLW02) parallels the summed concentration of mangrove pollen(SCMP) with a more positive correlation than that of YLW03(R=0.85, P=0.01), indicating that the trunk outlet of tidal creeks must have been the site where mangrove production gathered from the overall forest rather than from local production. The variations in the CLFM of both cores indicate that overall the mangrove forests in the Yingluo Bay have increasingly flourished ove
文摘改进的奇异值分解(advanced singular value decomposition,ASVD)方法,是对经过空间均匀化订正的格、站点网资料的奇异值分解(singular value decomposition,SVD)方法。根据奇异向量与经验正交函数(empirical orthogonal function,EOF)的关系,给出了格、站点网资料SVD方法中均匀化订正的方法,进而得到了改进的奇异值分解(ASVD)方法。将ASVD方法、SVD方法用于中国60a(1951—2010年)160站冬季气温、降水同期相关系数矩阵C的分析,结果表明:ASVD方法的前4个主要模态的模方拟合率和累积模方拟合率均明显高于SVD方法;ASVD方法前两个奇异向量典型场图上高绝对值区与C模方图上高值区的关系明显较SVD方法合理。由此论证了SVD方法中资料均匀化订正的必要性,验证了实际分析中ASVD方法的效果。
