In this study, the relationship between El Nifio-Southern Oscillation （ENSO） and winter rainfall over Southeast China （SC） is demonstrated based on instrumental and reanalysis data. The results show that ENSO and ...In this study, the relationship between El Nifio-Southern Oscillation （ENSO） and winter rainfall over Southeast China （SC） is demonstrated based on instrumental and reanalysis data. The results show that ENSO and SC winter rainfall （ENSO-SC rainfall） are highly correlated and intimately coupled through an anomalous high pressure over the northwestern Pacific. In mature phase, El Nifio （La Nina） events can cause more （less） rainfall over SC in winter. Due to the persistence and spring barrier of ENSO, SC winter rainfall has potential predictability of about half a year ahead with ENSO as a predictor.展开更多
采用1958～2002年海洋同化资料SODA（Simple Ocean Data Assimilation）的海温场，定义了东印度洋。西太平洋永久性暖池（简称印．太暖池）指数，即不随季节变化的27．5℃等温面所包含的〉27．5℃的暖水体积或强度，并采用功率谱和小波...采用1958～2002年海洋同化资料SODA（Simple Ocean Data Assimilation）的海温场，定义了东印度洋。西太平洋永久性暖池（简称印．太暖池）指数，即不随季节变化的27．5℃等温面所包含的〉27．5℃的暖水体积或强度，并采用功率谱和小波分析的方法研究了其周期变化特征。结果表明，印度洋暖池和西太平洋暖池均具有显著的准10a的周期振荡和1976～1986年前后的年代际突变特征，暖池由1976年前的“冷”暖池转变为1986年后的“热”暖池；暖池指数的季节循环也存在显著的年代际突变特征，特别是西太平洋暖池在异常暖年代其季节变化还呈现出明显的增暖趋势；暖池三维结构的年代际变化主要表现为在暖年代热带南印度洋暖水的向西向南扩张和西太平洋暖池东边界的向东及北边界的向北扩张，暖异常主要分布在60m以浅的上混合层中暖池的东边界区域，而其下面的温跃层内则为更强的异常降温，垂向上表现出上暖下冷的斜压模态结构，而温跃层和混合层深度的变化在不同暖池区则有不同的特点，表明东印度洋暖池和西太平洋暖池的年代际变化可能由不同的机制引起，尚需进一步分析其海洋动力学和热力学过程。展开更多
This paper presents a concise summary of the studies on interdecadal variability of the East Asian winter monsoon （EAWM） from three main perspectives. （1） The EAWM has been significantly affected by global climate...This paper presents a concise summary of the studies on interdecadal variability of the East Asian winter monsoon （EAWM） from three main perspectives. （1） The EAWM has been significantly affected by global climate change. Winter temperature in China has experienced three stages of variations from the beginning of the 1950s： a cold period （from the beginning of the 1950s to the early or mid 1980s）, a warm period （from the early or mid 1980s to the early 2000s）, and a hiatus period in recent 10 years （starting from 1998）. The strength of the EAWM has also varied in three stages： a stronger winter monsoon period （1950 to 1986/87）, a weaker period （1986/87 to 2004/05）, and a strengthening period （from 2005）. （2） Corresponding to the interdecadal variations of the EAWM, the East Asian atmospheric circulation, winter temperature of China, and the occurrence of cold waves over China have all exhibited coherent interdecadal variability. The upper-level zonal circulation was stronger, the mid-tropospheric trough over East Asia was deeper with stronger downdrafts behind the trough, and the Siberian high was stronger during the cold period than during the warm period. （3） The interdecadal variations of the EAWM seem closely related to major modes of variability in the atmospheric circulation and the Pacific sea surface temperature. When the Northern Hemisphere annular mode/Arctic Oscillation and the Pacific decadal oscillation were in negative （positive） phase, the EAWM was stronger （weaker）, leading to colder （warmer） temperatures in China. In addition, the negative （positive） phase of the Atlantic multi decadal oscillation coincided with relatively cold （warm） temperatures and stronger （weaker） EAWMs. It is thus inferred that the interdecadal variations in the ocean may be one of the most important natural factors influencing long-term variability in the EAWM, although global warming may have also played a significant role in weakening the EAWM.展开更多
Based on daily precipitation data, the spatial-temporal features of heavy rainfall events （HREs） during 1960-2009 are investigated. The results indicate that the HREs experienced strong decadal variability in the pa...Based on daily precipitation data, the spatial-temporal features of heavy rainfall events （HREs） during 1960-2009 are investigated. The results indicate that the HREs experienced strong decadal variability in the past 50 years, and the decadal features varied across regions. More HRE days are observed in the 1960s, 1980s, and 1999s over Northeast China （NEC）; in the 1960s, 1970s, and 1990s over North China （NC）; in the early 1960s, 1980s, and 2000s over the Huaihe River basin （HR）; in the 1970s 1990s over the mid-lower reaches of the Yangtze River valley （YR）; and in the 1970s and 1990s over South China （SC）. These decadal changes of HRE days in eastern China are closely associated with the decadal variations of water content and stratification stability of the local atmosphere. The intensity of HREs in each sub-region is also characterized by strong decadal variability. The HRE intensity and frequency co-vary on the long-term trend, and show consistent variability over NEC, NC, and YR, but inconsistent variability over SC and HR. Further analysis of the relationships between the annual rainfall and HRE frequency as well as intensity indicates that the HRE frequency is the major contributor to the total rainfall variability in eastern China, while the HRE intensity shows only relative weak contribution.展开更多
The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credib...The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credible quantitative estimates of future climate change; however, the mismatches between the IPCC AR4 model ensembles and the observations, especially the multi-decadal variability (MDV), have cast shadows on the confidence of the model-based decadal projections of future cli mate. This paper reports an evaluation of many individual runs of AR4 models in the simulation of past global mean tempera ture. We find that most of the individual model runs fail to reproduce the MDV of past climate, which may have led to the overestimation of the projection of global warming for the next 40 years or so. Based on such an evaluation, we propose an al ternative approach, in which the MDV signal is taken into account, to project the global mean temperature for the next 40 years and obtain that the global warming during 2011–2050 could be much smaller than the AR4 projection.展开更多
基金supported by the National Natural Science Foundation of China(NSFC) (Grant Nos.40906003 and 40830106)the National Basic Research Program of China(Grant No.2012CB 955603)
文摘In this study, the relationship between El Nifio-Southern Oscillation （ENSO） and winter rainfall over Southeast China （SC） is demonstrated based on instrumental and reanalysis data. The results show that ENSO and SC winter rainfall （ENSO-SC rainfall） are highly correlated and intimately coupled through an anomalous high pressure over the northwestern Pacific. In mature phase, El Nifio （La Nina） events can cause more （less） rainfall over SC in winter. Due to the persistence and spring barrier of ENSO, SC winter rainfall has potential predictability of about half a year ahead with ENSO as a predictor.
文摘采用1958～2002年海洋同化资料SODA（Simple Ocean Data Assimilation）的海温场，定义了东印度洋。西太平洋永久性暖池（简称印．太暖池）指数，即不随季节变化的27．5℃等温面所包含的〉27．5℃的暖水体积或强度，并采用功率谱和小波分析的方法研究了其周期变化特征。结果表明，印度洋暖池和西太平洋暖池均具有显著的准10a的周期振荡和1976～1986年前后的年代际突变特征，暖池由1976年前的“冷”暖池转变为1986年后的“热”暖池；暖池指数的季节循环也存在显著的年代际突变特征，特别是西太平洋暖池在异常暖年代其季节变化还呈现出明显的增暖趋势；暖池三维结构的年代际变化主要表现为在暖年代热带南印度洋暖水的向西向南扩张和西太平洋暖池东边界的向东及北边界的向北扩张，暖异常主要分布在60m以浅的上混合层中暖池的东边界区域，而其下面的温跃层内则为更强的异常降温，垂向上表现出上暖下冷的斜压模态结构，而温跃层和混合层深度的变化在不同暖池区则有不同的特点，表明东印度洋暖池和西太平洋暖池的年代际变化可能由不同的机制引起，尚需进一步分析其海洋动力学和热力学过程。
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2012CB417205 and 2013CB430202)National Natural Science Foundation of China(41130960)+1 种基金China Meteorological Administration Special Public Welfare Research Fund(GYHY201406001)National Science and Technology Support Program of China(2009BAC51B02)
文摘This paper presents a concise summary of the studies on interdecadal variability of the East Asian winter monsoon （EAWM） from three main perspectives. （1） The EAWM has been significantly affected by global climate change. Winter temperature in China has experienced three stages of variations from the beginning of the 1950s： a cold period （from the beginning of the 1950s to the early or mid 1980s）, a warm period （from the early or mid 1980s to the early 2000s）, and a hiatus period in recent 10 years （starting from 1998）. The strength of the EAWM has also varied in three stages： a stronger winter monsoon period （1950 to 1986/87）, a weaker period （1986/87 to 2004/05）, and a strengthening period （from 2005）. （2） Corresponding to the interdecadal variations of the EAWM, the East Asian atmospheric circulation, winter temperature of China, and the occurrence of cold waves over China have all exhibited coherent interdecadal variability. The upper-level zonal circulation was stronger, the mid-tropospheric trough over East Asia was deeper with stronger downdrafts behind the trough, and the Siberian high was stronger during the cold period than during the warm period. （3） The interdecadal variations of the EAWM seem closely related to major modes of variability in the atmospheric circulation and the Pacific sea surface temperature. When the Northern Hemisphere annular mode/Arctic Oscillation and the Pacific decadal oscillation were in negative （positive） phase, the EAWM was stronger （weaker）, leading to colder （warmer） temperatures in China. In addition, the negative （positive） phase of the Atlantic multi decadal oscillation coincided with relatively cold （warm） temperatures and stronger （weaker） EAWMs. It is thus inferred that the interdecadal variations in the ocean may be one of the most important natural factors influencing long-term variability in the EAWM, although global warming may have also played a significant role in weakening the EAWM.
基金Supported by the National Science and Technology Support Program of China (2007BAC03A01)Strategic Priority Research Program on Climate Change of the Chinese Academy of Sciences (XDA05090306)+1 种基金National Basic Research and Development (973) Program of China (2012CB955401)National Natural Science Foundation of China (40905041)
文摘Based on daily precipitation data, the spatial-temporal features of heavy rainfall events （HREs） during 1960-2009 are investigated. The results indicate that the HREs experienced strong decadal variability in the past 50 years, and the decadal features varied across regions. More HRE days are observed in the 1960s, 1980s, and 1999s over Northeast China （NEC）; in the 1960s, 1970s, and 1990s over North China （NC）; in the early 1960s, 1980s, and 2000s over the Huaihe River basin （HR）; in the 1970s 1990s over the mid-lower reaches of the Yangtze River valley （YR）; and in the 1970s and 1990s over South China （SC）. These decadal changes of HRE days in eastern China are closely associated with the decadal variations of water content and stratification stability of the local atmosphere. The intensity of HREs in each sub-region is also characterized by strong decadal variability. The HRE intensity and frequency co-vary on the long-term trend, and show consistent variability over NEC, NC, and YR, but inconsistent variability over SC and HR. Further analysis of the relationships between the annual rainfall and HRE frequency as well as intensity indicates that the HRE frequency is the major contributor to the total rainfall variability in eastern China, while the HRE intensity shows only relative weak contribution.
基金supported by the National Basic Research Program of Chi-na (Grant No. 2011CB952000)the National Natural Science Founda-tion of China (Grant No. 40810059003)+1 种基金Qian Cheng was partly supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (Grant No. XDA05090103)Wu Zhaohua was supported by the Natural Science Foundation of USA (Grant No. ATM-0917743)
文摘The Fourth Assessment Report (AR4) of the Intergovernmental Panel of Climate Change (IPCC) concluded that the climate projection using climate models that took account of both human and natural factors provided credible quantitative estimates of future climate change; however, the mismatches between the IPCC AR4 model ensembles and the observations, especially the multi-decadal variability (MDV), have cast shadows on the confidence of the model-based decadal projections of future cli mate. This paper reports an evaluation of many individual runs of AR4 models in the simulation of past global mean tempera ture. We find that most of the individual model runs fail to reproduce the MDV of past climate, which may have led to the overestimation of the projection of global warming for the next 40 years or so. Based on such an evaluation, we propose an al ternative approach, in which the MDV signal is taken into account, to project the global mean temperature for the next 40 years and obtain that the global warming during 2011–2050 could be much smaller than the AR4 projection.
