The East Asian summer monsoon(EASM)and its related change of surface temperature in the past century were not clearly addressed due to absence of atmospheric reanalysis data before 1948.On the benchmark of station-obs...The East Asian summer monsoon(EASM)and its related change of surface temperature in the past century were not clearly addressed due to absence of atmospheric reanalysis data before 1948.On the benchmark of station-observed sea level pressure(SLP)in China,we utilized multiple SLP datasets and evaluated their qualities in measuring the SLP-based EASM index(EASMI).It is found that the EASMI based on the SLP of the Hadley center version 2(HadSLP2)has shown the best performance on the interannual and decadal time scales.Instead of showing a linear weakening trend pointed out by the previous study,the EASMI has likely exhibited the decadal variability,characterized by weakened trends during 1880–1906,1921–1936,and 1960–2004,and with enhanced trends during 1906–1921 and 1936–1960,respectively.Corresponding to the weakened and enhanced periods of EASMI since the 1920s,the surface air temperature(SAT)index(SATI)averaged in eastern China has likely shown a warming and a cooling trend,respectively.However,the decadal abrupt transitions between the two indices do not occur concurrently,which results in a weak correlation between two indices on the decadal time scale.Further analysis indicates that there are four key regions where the SAT is significantly correlated with the EASMI,suggesting the joint impact of surface temperature in Asia-Pacific on the EASM during 1880–2004.In which,the decadal change of SAT near the Lake Baikal plays an important role in the linear trends of the EASM before and after 1960.展开更多
Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and...Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for Environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South China Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.展开更多
基金supported by the National Natural Science Foundation of China(90711003,40921003 and 40805036)the Strategic Priority ResearchProgram-Climate Change:Carbon Budget and Relevant Issues of the Chinese Academy of Sciences(XDA05090408)+1 种基金the National Basic Research Program of China(2011FY120300)the Basic Scientific Project of Chinese Academy of Meteorology Sciences(2013Z002)
文摘The East Asian summer monsoon(EASM)and its related change of surface temperature in the past century were not clearly addressed due to absence of atmospheric reanalysis data before 1948.On the benchmark of station-observed sea level pressure(SLP)in China,we utilized multiple SLP datasets and evaluated their qualities in measuring the SLP-based EASM index(EASMI).It is found that the EASMI based on the SLP of the Hadley center version 2(HadSLP2)has shown the best performance on the interannual and decadal time scales.Instead of showing a linear weakening trend pointed out by the previous study,the EASMI has likely exhibited the decadal variability,characterized by weakened trends during 1880–1906,1921–1936,and 1960–2004,and with enhanced trends during 1906–1921 and 1936–1960,respectively.Corresponding to the weakened and enhanced periods of EASMI since the 1920s,the surface air temperature(SAT)index(SATI)averaged in eastern China has likely shown a warming and a cooling trend,respectively.However,the decadal abrupt transitions between the two indices do not occur concurrently,which results in a weak correlation between two indices on the decadal time scale.Further analysis indicates that there are four key regions where the SAT is significantly correlated with the EASMI,suggesting the joint impact of surface temperature in Asia-Pacific on the EASM during 1880–2004.In which,the decadal change of SAT near the Lake Baikal plays an important role in the linear trends of the EASM before and after 1960.
基金supported by the Innovation Project of the Chinese Academy of Sciences(Grant No.KZCX3-SW-221)the National Natural Science Foundation of China(Grant Nos.40233033 and 40365001).
文摘Based on the daily outgoing longwave radiation (OLR) data from National Oceanic and At- mospheric Administration (NOAA) satellites, the Cli- mate Prediction Center’s merged analysis of pre- cipitation (CMAP) data and the National Centers for Environmental Prediction/National Center for At- mospheric Research (NCEP/NCAR) reanalysis dataset, the mean intraseasonal variability of the Asian summer monsoon (ASM) is investigated by using power spectrum analysis, band-pass filter, and diagnostic analyses. The processes of the onset and advance of monsoon over the southern part of Indo- china Peninsula, the east coast of Bay of Bengal, the South China Sea and the Indian subcontinent are explored. It is found that there is an abrupt change in OLR, precipitation and zonal wind during the onset and advance of the ASM. It is also indicated that the southern part of Indochina Peninsula and the adja- cent Andaman Sea is the region where the earliest onset of the ASM occurs in the 2nd pentad of May.
