Changma is the most important supplier of water resource in Korea. However, its interannual variation may cause either floods or droughts time to time in many regions of Korea. A number of studies on Changma have been...Changma is the most important supplier of water resource in Korea. However, its interannual variation may cause either floods or droughts time to time in many regions of Korea. A number of studies on Changma have been done in many subjects, such as the on-set and retreat timing, duration of Changma, and its interannual variation, which may cause either wet or dry Changma, and the heavy rainfall phenomena associated with the Changma front. Also, the subjects covered the dynamical situation of Changma compared to that of Baiu and Mei-yu as a part of East Asian monsoon circulation, and relation between Changma and tropical Pacific sea-surface temperature (SST) through atmosphere-ocean interaction, etc. A numerical study is presented in this paper to check the teleconnection between the behavior of Changma front and the variation of tropical Pacific SST. The difference in the lower level streamfunction between theEl Nio event of 1987 and the La Nia event of 1988 illustrates that the cross-equatorial and westerly wind crossing over the India and Indo-China peninsula were weak during the summer of 1988 compared to 1987. This may cause the drought of 1988 in East Asia by reducing moisture supply from the Indian Ocean and the south-western Pacific. Even though there are numerous research activities on the Changma, our knowledge on the Changma is still limited to explain the mechanism of interannual variation of Changma and to provide a proper prediction of precipitation due to both geographical location of Korea and its complex topography. In collaboration with the international field observational projects, such as GAME and SCSMEX, the Korea Monsoon Experiment (KORMEX) has been planned by several scientists in Korea to improve our knowledge on the atmospheric circulation and water cycle related to the East Asian monsoon and to provide necessary information to predict both short- and long-term variation of rainfall during the Changma season.展开更多
The associations of onset and withdrawal of the rainy season in South Korea (called Changma) have been examined. Composite studies showed that there are significant differences in circulations between extremely early ...The associations of onset and withdrawal of the rainy season in South Korea (called Changma) have been examined. Composite studies showed that there are significant differences in circulations between extremely early and late onset (or withdrawals) not only over East Asia, but also over remote areas. The in situ significant differences include the upper-level jet over East Asia and the subtropical anticyclone over the western North Pacific at lower levels. The significant remote associations include the Indian monsoon and ENSO. The Indian summer monsoon is related to both onset and withdrawal of the Changma, while ENSO has a significant relation only to onset, but not to withdrawal. Key words Changma - Onset - Withdrawal - Interannual variation - Association This study was supported by the National Key Programme for Developing Basic Sciences (G1998040900, Part I), Brain Pool Program (Grant No. 991-5-8) funded by Korea Science and Engineering Foundation, and the Natural Hazard Prevention Research Project, one of the Critical Technology-21 Programs, funded by the Ministry of Science and Technology of Korea.展开更多
Most modern birds have scales covering feet,but our knowledge of early avian scales is limited,mainly due to their scarcity in the fossil record.Here we describe the morphological details of scutellate and interstitia...Most modern birds have scales covering feet,but our knowledge of early avian scales is limited,mainly due to their scarcity in the fossil record.Here we describe the morphological details of scutellate and interstitial scales preserved in IVPP V15077,a specimen of the Early Cretaceous bird Gansus from the Changma Basin in northwestern Gansu Province,Northwest China.These results,combined with previous reports of scutate and reticulate scales,show that all four types of scales present in modern birds already appeared in the Early Cretaceous.The phylogenetic distribution of skin appendages of feet,including feathers and scales,shows that non-avian dinosaurs already evolved scales resembling those in modern birds,and that scales can coexist with feathers on feet,suggesting that avian scales may be homologue with scales of non-avian dinosaurs.However,to further test this hypothesis,more research combined with a strengthened focus on detecting specimens with soft tissue preservation is necessary.展开更多
文摘Changma is the most important supplier of water resource in Korea. However, its interannual variation may cause either floods or droughts time to time in many regions of Korea. A number of studies on Changma have been done in many subjects, such as the on-set and retreat timing, duration of Changma, and its interannual variation, which may cause either wet or dry Changma, and the heavy rainfall phenomena associated with the Changma front. Also, the subjects covered the dynamical situation of Changma compared to that of Baiu and Mei-yu as a part of East Asian monsoon circulation, and relation between Changma and tropical Pacific sea-surface temperature (SST) through atmosphere-ocean interaction, etc. A numerical study is presented in this paper to check the teleconnection between the behavior of Changma front and the variation of tropical Pacific SST. The difference in the lower level streamfunction between theEl Nio event of 1987 and the La Nia event of 1988 illustrates that the cross-equatorial and westerly wind crossing over the India and Indo-China peninsula were weak during the summer of 1988 compared to 1987. This may cause the drought of 1988 in East Asia by reducing moisture supply from the Indian Ocean and the south-western Pacific. Even though there are numerous research activities on the Changma, our knowledge on the Changma is still limited to explain the mechanism of interannual variation of Changma and to provide a proper prediction of precipitation due to both geographical location of Korea and its complex topography. In collaboration with the international field observational projects, such as GAME and SCSMEX, the Korea Monsoon Experiment (KORMEX) has been planned by several scientists in Korea to improve our knowledge on the atmospheric circulation and water cycle related to the East Asian monsoon and to provide necessary information to predict both short- and long-term variation of rainfall during the Changma season.
基金the National Key Programme for Developing Basic Sciences(G1998040900, Part I) Brain Pool Program (Grant No. 991-5-8) funde
文摘The associations of onset and withdrawal of the rainy season in South Korea (called Changma) have been examined. Composite studies showed that there are significant differences in circulations between extremely early and late onset (or withdrawals) not only over East Asia, but also over remote areas. The in situ significant differences include the upper-level jet over East Asia and the subtropical anticyclone over the western North Pacific at lower levels. The significant remote associations include the Indian monsoon and ENSO. The Indian summer monsoon is related to both onset and withdrawal of the Changma, while ENSO has a significant relation only to onset, but not to withdrawal. Key words Changma - Onset - Withdrawal - Interannual variation - Association This study was supported by the National Key Programme for Developing Basic Sciences (G1998040900, Part I), Brain Pool Program (Grant No. 991-5-8) funded by Korea Science and Engineering Foundation, and the Natural Hazard Prevention Research Project, one of the Critical Technology-21 Programs, funded by the Ministry of Science and Technology of Korea.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41922011,41872016,41902013,42288201)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB26000000)the Fundamental Research Funds for the Central Universities,China(Grant No.0206-14380137)。
文摘Most modern birds have scales covering feet,but our knowledge of early avian scales is limited,mainly due to their scarcity in the fossil record.Here we describe the morphological details of scutellate and interstitial scales preserved in IVPP V15077,a specimen of the Early Cretaceous bird Gansus from the Changma Basin in northwestern Gansu Province,Northwest China.These results,combined with previous reports of scutate and reticulate scales,show that all four types of scales present in modern birds already appeared in the Early Cretaceous.The phylogenetic distribution of skin appendages of feet,including feathers and scales,shows that non-avian dinosaurs already evolved scales resembling those in modern birds,and that scales can coexist with feathers on feet,suggesting that avian scales may be homologue with scales of non-avian dinosaurs.However,to further test this hypothesis,more research combined with a strengthened focus on detecting specimens with soft tissue preservation is necessary.
