The characteristics of heavy precipitation occurrence in autumn（the month of September） over North China are investigated using daily observational data.Results indicate that heavy precipitation events experienced a...The characteristics of heavy precipitation occurrence in autumn（the month of September） over North China are investigated using daily observational data.Results indicate that heavy precipitation events experienced a significant decadal increase in 2000/2001.Further investigation reveals a close connection between heavy precipitation occurrence and simultaneous North Pacific SST.The SST anomaly over the North Pacific can result in intensification of the western North Pacific subtropical high and increased water vapor transport from the tropical ocean,which benefits the occurrence of heavy precipitation over North China.However,the key region of North Pacific SST influencing heavy precipitation events over North China was different in the periods 1960-2000 and 2001-2014,being located over the eastern Ocean to China in the first period but more eastward in the second period.This drift in the key region of SST is partly responsible for the decadal increase in heavy precipitation events over North China since 2000/2001.Additionally,the changes in SST variability（a decrease in the eastern Ocean to China and an increase to its east） may have been the main reason for the eastward movement of the key region in the latter period.Certainly,more work is needed in the future to verify the findings of this study.展开更多
The Yellow Sea on the western continental margin of the North Pacific Ocean is of major ecological and economic importance. Four field surveys were conducted during May and November 2012, August 2015, and January 2016...The Yellow Sea on the western continental margin of the North Pacific Ocean is of major ecological and economic importance. Four field surveys were conducted during May and November 2012, August 2015, and January 2016, investigating seasonal variations in dissolved oxygen and carbonate system parameters of this marginal sea. Results showed that the Yellow Sea cold water mass accumulated respiration-induced CO_2 in subsurface and bottom waters in summer and autumn, leading to acidified seawaters with critical carbonate saturation states of aragonite(Ω_(arag)) of less than 1.5. These seriously acidified seawaters occupied one third of surveyed areas in summer and autumn, likely affecting local calcified organisms and benthic communities. In a future scenario for the 2050 s, in which the atmospheric CO_2 mole fraction increases by 100 μmol mol-1, half of the Yellow Sea benthos would be seasonally covered by acidified seawater having a critical Ω_(arag) of less than 1.5. The corresponding bottom-water p H_T would be around 7.85 in summer, and 7.80 in autumn. Of the China seas, the Yellow Sea cold water mass represents one of the ecosystems most vulnerable to ocean acidification.展开更多
基金jointly supported by the National Natural Science Foundation of China[grant numbers 41305061 and41210007]the CAS-PKU(Chinese Academy of Sciences-Peking University)Joint Research Program
文摘The characteristics of heavy precipitation occurrence in autumn（the month of September） over North China are investigated using daily observational data.Results indicate that heavy precipitation events experienced a significant decadal increase in 2000/2001.Further investigation reveals a close connection between heavy precipitation occurrence and simultaneous North Pacific SST.The SST anomaly over the North Pacific can result in intensification of the western North Pacific subtropical high and increased water vapor transport from the tropical ocean,which benefits the occurrence of heavy precipitation over North China.However,the key region of North Pacific SST influencing heavy precipitation events over North China was different in the periods 1960-2000 and 2001-2014,being located over the eastern Ocean to China in the first period but more eastward in the second period.This drift in the key region of SST is partly responsible for the decadal increase in heavy precipitation events over North China since 2000/2001.Additionally,the changes in SST variability（a decrease in the eastern Ocean to China and an increase to its east） may have been the main reason for the eastward movement of the key region in the latter period.Certainly,more work is needed in the future to verify the findings of this study.
基金supported by the State Key R&D Project of China(Grant No.2016YFA0601103)the National Natural Science Foundation of China(Grant Nos.91751207&41276061)+2 种基金the Visiting Fellowship in the State Key Laboratory of Marine Environmental Science(Xiamen University)the Fundamental Research Funds of Shandong UniversitySampling surveys were supported by the National Natural Science Foundation of China Open Ship-Time Projects in2012 and 2015
文摘The Yellow Sea on the western continental margin of the North Pacific Ocean is of major ecological and economic importance. Four field surveys were conducted during May and November 2012, August 2015, and January 2016, investigating seasonal variations in dissolved oxygen and carbonate system parameters of this marginal sea. Results showed that the Yellow Sea cold water mass accumulated respiration-induced CO_2 in subsurface and bottom waters in summer and autumn, leading to acidified seawaters with critical carbonate saturation states of aragonite(Ω_(arag)) of less than 1.5. These seriously acidified seawaters occupied one third of surveyed areas in summer and autumn, likely affecting local calcified organisms and benthic communities. In a future scenario for the 2050 s, in which the atmospheric CO_2 mole fraction increases by 100 μmol mol-1, half of the Yellow Sea benthos would be seasonally covered by acidified seawater having a critical Ω_(arag) of less than 1.5. The corresponding bottom-water p H_T would be around 7.85 in summer, and 7.80 in autumn. Of the China seas, the Yellow Sea cold water mass represents one of the ecosystems most vulnerable to ocean acidification.
