Following disastrous flooding in several river valleys over eastern China in 1755, serious flooding occurred in the middle and lower reaches of the Yellow River in 1756 and 1757, a rarely seen precipitation pattern of...Following disastrous flooding in several river valleys over eastern China in 1755, serious flooding occurred in the middle and lower reaches of the Yellow River in 1756 and 1757, a rarely seen precipitation pattern of north-flood and south-drought in China for two successive years. This is a serious meteorological disaster and extreme climatic event taking place under the climatic background of a warm phase of the Little Ice Age. In this paper, by means of historical literature records, the rainy and flooding situation and the weather characteristics of these years are reconstructed and the maps depicting areas of prolonged rain, flood and concomitant famine, insect pest, and pestilence are made. The results show that, in 1755, the middle and lower reaches of the Yellow River and the Yangtze River, and the Huaihe River Basin experienced a prolonged rainy season with multiple torrential rain events. The continuous rainy period exceeded 40 days in the Huang-Huai Region. An early Meiyu occurred, and the duration of the Meiyu period in the lower Yangtze River Basin was 43 days, the longest in the 18th century. Particularly in Nanjing the annual rainfall of 1755 was 1,378 mm, the highest record of the 18th century. The year of 1755 is characterized by lower temperature in summer, early frost in autumn, and heavy snowfall and freezing rain in winter. These characteristics are extremely similar to those of 1823 and 1954, two typical years of extreme rainfall. And all these three years with extreme precipitation axe corresponding to the minimum phase of the solar activity cycle.展开更多
While Arctic sea ice has been decreasing in recent decades that is largely due to anthropogenic forcing,the extent of Antarctic sea ice showed a positive trend during 1979–2015, followed by an abrupt decrease. The sh...While Arctic sea ice has been decreasing in recent decades that is largely due to anthropogenic forcing,the extent of Antarctic sea ice showed a positive trend during 1979–2015, followed by an abrupt decrease. The shortness of the satellite record limits our ability to quantify the possible contribution of anthropogenic forcing and internal variability to the observed Antarctic sea ice variability. In this study,ice core and fast ice records with annual resolution from six sites are used to reconstruct the annualresolved northernmost latitude of sea ice edge(NLSIE) for different sectors of the Southern Ocean, including the Weddell Sea(WS), Bellingshausen Sea(BS), Amundsen Sea(AS), Ross Sea(RS), and the Indian and western Pacific Ocean(Ind WPac). The linear trends of the NLSIE are analyzed for each sector for the past100–200 years and found to be à0.08°, à0.17°, +0.07°, +0.02°, and à0.03° per decade(!95% confidence level) for the WS, BS, AS, RS, and Ind WPac, respectively. For the entire Antarctic, our composite NLSIE shows a decreasing trend(à0.03° per decade, 99% confidence level) during the 20 th century, with a rapid decline in the mid-1950 s. It was not until the early 1980 s that the observed increasing trend occurred. A comparison with major climate indices shows that the long-term linear trends in all five sectors are largely dominated by the changes in the Southern Annular Mode(SAM). The multi-decadal variability in WS,BS, and AS is dominated by the Interdecadal Pacific Oscillation, whereas that in the Ind WPac and RS is dominated by the SAM.展开更多
基金supported in part by the China Global Change Research Program(No.2010CB950103)the National Science and Technology Support Program of China(No.2007BAC29B01)
文摘Following disastrous flooding in several river valleys over eastern China in 1755, serious flooding occurred in the middle and lower reaches of the Yellow River in 1756 and 1757, a rarely seen precipitation pattern of north-flood and south-drought in China for two successive years. This is a serious meteorological disaster and extreme climatic event taking place under the climatic background of a warm phase of the Little Ice Age. In this paper, by means of historical literature records, the rainy and flooding situation and the weather characteristics of these years are reconstructed and the maps depicting areas of prolonged rain, flood and concomitant famine, insect pest, and pestilence are made. The results show that, in 1755, the middle and lower reaches of the Yellow River and the Yangtze River, and the Huaihe River Basin experienced a prolonged rainy season with multiple torrential rain events. The continuous rainy period exceeded 40 days in the Huang-Huai Region. An early Meiyu occurred, and the duration of the Meiyu period in the lower Yangtze River Basin was 43 days, the longest in the 18th century. Particularly in Nanjing the annual rainfall of 1755 was 1,378 mm, the highest record of the 18th century. The year of 1755 is characterized by lower temperature in summer, early frost in autumn, and heavy snowfall and freezing rain in winter. These characteristics are extremely similar to those of 1823 and 1954, two typical years of extreme rainfall. And all these three years with extreme precipitation axe corresponding to the minimum phase of the solar activity cycle.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA19070103)the National Key Research & Development Program of China (2018YFA0605901)+1 种基金the State Key Laboratory of Cryospheric Science (SKLCS-ZZ-2021)the National Natural Science Foundation of China (42071086, 41425003, 41941009)。
文摘While Arctic sea ice has been decreasing in recent decades that is largely due to anthropogenic forcing,the extent of Antarctic sea ice showed a positive trend during 1979–2015, followed by an abrupt decrease. The shortness of the satellite record limits our ability to quantify the possible contribution of anthropogenic forcing and internal variability to the observed Antarctic sea ice variability. In this study,ice core and fast ice records with annual resolution from six sites are used to reconstruct the annualresolved northernmost latitude of sea ice edge(NLSIE) for different sectors of the Southern Ocean, including the Weddell Sea(WS), Bellingshausen Sea(BS), Amundsen Sea(AS), Ross Sea(RS), and the Indian and western Pacific Ocean(Ind WPac). The linear trends of the NLSIE are analyzed for each sector for the past100–200 years and found to be à0.08°, à0.17°, +0.07°, +0.02°, and à0.03° per decade(!95% confidence level) for the WS, BS, AS, RS, and Ind WPac, respectively. For the entire Antarctic, our composite NLSIE shows a decreasing trend(à0.03° per decade, 99% confidence level) during the 20 th century, with a rapid decline in the mid-1950 s. It was not until the early 1980 s that the observed increasing trend occurred. A comparison with major climate indices shows that the long-term linear trends in all five sectors are largely dominated by the changes in the Southern Annular Mode(SAM). The multi-decadal variability in WS,BS, and AS is dominated by the Interdecadal Pacific Oscillation, whereas that in the Ind WPac and RS is dominated by the SAM.
