Instead of conventional East Asian winter monsoon indices （EAWMIs）, we simply use two large-scale teleconnection patterns to represent long-term variations in the EAWM. First, the Urals blocking pattern index （UBI...Instead of conventional East Asian winter monsoon indices （EAWMIs）, we simply use two large-scale teleconnection patterns to represent long-term variations in the EAWM. First, the Urals blocking pattern index （UBI） is closely related to cold air advection from the high latitudes towards western Siberia, such that it shows an implicit linkage with the Siberian high intensity and the surface air temperature （SAT） variations north of 40°N in the EAWM region. Second, the well-known western Pacific teleconnection index （WPI） is connected with the meridional displacement of the East Asian jet stream and the East Asian trough. This is strongly related to the SAT variations in the coastal area south of 40°N in the EAWM region. The temperature variation in the EAWM region is also represented by the two dominant temperature modes, which are called the northern temperature mode （NTM） and the southern temperature mode （STM）. Compared to 19 existing EAWMIs and other well-known teleconnection patterns, the UBI shows the strongest correlation with the NTM, while the WPI shows an equally strong correlation with the STM as four EAWMIs. The UBI-NTM and WPI-STM relationships are robust when the correlation analysis is repeated by （1） the 31-year running correlation and （2） the 8-year high-pass and low-pass filter. Hence, these results are useful for analyzing the large-scale teleconnections of the EAWM and for evaluating this issue in climate models. Int particular, more studies should focus on the teleconnection patterns over extratropical Eurasia.展开更多
Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-...Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-August from 1951 to 2006, and focusing on the East Asia-West Pacific region （10°-80°N, 70°-180°E）, interannual variation of East Asian summer monsoon （EASM） and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function （EOF） analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows： （1） EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal dipole oscillation mode （APD） between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. （2） EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern （EAP）, and EAP index can also be used as an EASM intensity index. （3） The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa （or 850 hPa）. The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of -0.23, which passes the confidence test at 0.10 level. （4） Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.展开更多
The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution vers...The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） model.The model was driven by both natural and anthropogenic forcing agents.Major features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 20th Century Warming （20CW）,were generally consistent with the reconstructions.The simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 20CW to be unprecedented over the last millennium in the simulation.The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation.The simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental regions.Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales.The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different reconstructions.The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south.Both the zonal and meridional thermal contrast were enhanced during the MCA.This temperature anomaly pattern favored a stronger monsoon circulation.展开更多
Recent advances in studies of the structural characteristics and temporal-spatial variations of the East Asian monsoon （EAM） system and the impact of this system on severe climate disasters in China are reviewed. Pr...Recent advances in studies of the structural characteristics and temporal-spatial variations of the East Asian monsoon （EAM） system and the impact of this system on severe climate disasters in China are reviewed. Previous studies have improved our understanding of the basic characteristics of horizontal and vertical structures and the annual cycle of the EAM system and the water vapor transports in the EAM region. Many studies have shown that the EAM system is a relatively independent subsystem of the Asian- Australian monsoon system, and that there exists an obvious quasi-biennial oscillation with a meridional tripole pattern distribution in the interannual variations of the EAM system. Further analyses of the basic physical processes, both internal and external, that influence the variability of the EAM system indicate that the EAM system may be viewed as an atmosphere-ocean-land coupled system, referred to the EAM climate system in this paper. Further, the paper discusses how the interaction and relationships among various components of this system can be described through the East Asia Pacific （EAP） teleconnection pattern and the teleconnection pattern of meridional upper-tropospheric wind anomalies along the westerly jet over East Asia. Such reasoning suggests that the occurrence of severe floods in the Yangtze and Hualhe River valleys and prolonged droughts in North China are linked, respectively~ to the background interannual and interdecadal variability of the EAM climate system. Besides, outstanding scientific issues related to the EAM system and its impact on climate disasters in China are also discussed.展开更多
Research into the diagnostic methods and patterns of traditional East Asian medical （TEAM） systems of practice such as acupuncture and herbal medicine face certain challenges due to the nature of thinking in TEAM an...Research into the diagnostic methods and patterns of traditional East Asian medical （TEAM） systems of practice such as acupuncture and herbal medicine face certain challenges due to the nature of thinking in TEAM and the subjective basis of judgments made in practice. The TEAM-based diagnosis can take into account various findings and signs such as the appearance of the tongue, palpable qualities of the radial pulses, palpable qualities and findings on the abdomen, the complexion of the patient and so on. Both diagnostic findings and the patterns of diagnosis cannot be assumed to have objective bases or to be causally related to the complaints of the patient. However, the diagnoses of TEAM based acupuncture and herbal medicine have tended to look at pictures of the whole patient and rather than focus on a particular symptom, they have looked across a myriad of signs and symptoms to decide or identify the ＇pattern＇ of diagnosis according to the theory in question. Although open for selective and subjective biases each diagnosis pattern always comes with a prescribed treatment tailored to the pattern. Further, the same research requirements needed for the validation of the diagnoses are needed also for these clinical observations and judgments. Hence, it is necessary, albeit challenging for research on TEAM diagnoses to first address these issues before proceeding to more complex investigations such as the development of instruments for making diagnostic observations, instruments for forming diagnostic conclusions or studies investigating the physiological bases of the diagnostic patterns. Preliminary work has started and instruments have been made, but we suggest that any instrumentation must necessarily be first validated by matching of the calibrated or scaled observations or judgments to observations made and agreed upon by relevant experts. Reliability of all observations and judgments are needed before any other tool, technology or more advanced approach can proceed and also whenever the natural system of diagnosis-treatment is applied in clinical trials. In this paper the authors highlight the core problems and describe a step wise process for addressing them.展开更多
利用850 hPa的纬向风异常建立一个逐候东亚-太平洋(East Asian Pacific,EAP)型指数,研究其季节内演变特征,发现东亚-太平洋型经向波列是东亚夏季风季节内变化的主要模态。其演变过程为:扰动首先出现在北太平洋中部,并通过正压不稳定过...利用850 hPa的纬向风异常建立一个逐候东亚-太平洋(East Asian Pacific,EAP)型指数,研究其季节内演变特征,发现东亚-太平洋型经向波列是东亚夏季风季节内变化的主要模态。其演变过程为:扰动首先出现在北太平洋中部,并通过正压不稳定过程从基本气流中获得能量而发展,在高层罗斯贝波能量向南频散,激发热带对流异常和赤道罗斯贝波,并相互锁相,因赤道罗斯贝波受β效应影响而共同向西移动。热带对流和环流异常在菲律宾附近达到最强,此时在东亚沿岸出现经向三极型波列,此后中低纬度异常继续向西北方向移动,使降水异常在长江流域能维持较长时间。东亚-太平洋型在东亚发展和维持有以下原因:首先,菲律宾暖水上空的对流和低层环流之间存在正反馈;其次,由于海陆热力差异导致暖大陆和冷海洋之间存在特殊的纬向温度梯度和北风垂直切变,东亚-太平洋型在经向上有向北倾斜的斜压结构,能通过斜压能量转换从平均有效位能中获得能量,同时,也能从经向温度梯度的平均有效位能中获得能量。展开更多
基金supported by Shenzhen Research Project(Grant No.GJHS20120820144245169)the French/Hong Kong Joint Research Project(No.F-HK002/12T)
文摘Instead of conventional East Asian winter monsoon indices （EAWMIs）, we simply use two large-scale teleconnection patterns to represent long-term variations in the EAWM. First, the Urals blocking pattern index （UBI） is closely related to cold air advection from the high latitudes towards western Siberia, such that it shows an implicit linkage with the Siberian high intensity and the surface air temperature （SAT） variations north of 40°N in the EAWM region. Second, the well-known western Pacific teleconnection index （WPI） is connected with the meridional displacement of the East Asian jet stream and the East Asian trough. This is strongly related to the SAT variations in the coastal area south of 40°N in the EAWM region. The temperature variation in the EAWM region is also represented by the two dominant temperature modes, which are called the northern temperature mode （NTM） and the southern temperature mode （STM）. Compared to 19 existing EAWMIs and other well-known teleconnection patterns, the UBI shows the strongest correlation with the NTM, while the WPI shows an equally strong correlation with the STM as four EAWMIs. The UBI-NTM and WPI-STM relationships are robust when the correlation analysis is repeated by （1） the 31-year running correlation and （2） the 8-year high-pass and low-pass filter. Hence, these results are useful for analyzing the large-scale teleconnections of the EAWM and for evaluating this issue in climate models. Int particular, more studies should focus on the teleconnection patterns over extratropical Eurasia.
基金funded by the Ministry of Science and Technology of the People’s Republic of China,No.2007DFB20210National Natural Science Foundation of China,No.90502003JICA China-Japan Technical Cooperative Project "China-Japanese Cooperative Research Center on Meteorological Disasters"
文摘Using NCEP/NCAR reanalysis geopotential height （GHT） and wind at 850 hPa, GHT at 500 hPa, precipitation rate, sea level pressure （SLP） and precipitation observations from more than 600 stations nationwide in June-August from 1951 to 2006, and focusing on the East Asia-West Pacific region （10°-80°N, 70°-180°E）, interannual variation of East Asian summer monsoon （EASM） and its correlations with general circulation and precipitation patterns are studied by using statistical diagnostic methods such as 9-point high pass filtering, empirical orthogonal function （EOF） analysis, composite analysis and other statistical diagnosis, etc. It is concluded as follows： （1） EOF analysis of SLP in the East Asia-West Pacific region shows the existence of the zonal dipole oscillation mode （APD） between the Mongolia depression and the West Pacific high, and APD index can be used as an intensity index of EASM. （2） EOF analysis of GHT anomalies at 500 hPa in the East Asia-West Pacific region shows that the first EOF mode is characterized with an obvious meridional East Asian pattern （EAP）, and EAP index can also be used as an EASM intensity index. （3） The composite analysis of high/low APD index years reveals the close correlation of APD index with EAP at 500 hPa （or 850 hPa）. The study shows an obvious opposite correlation exists between APD index and EAP index with a correlation coefficient of -0.23, which passes the confidence test at 0.10 level. （4） Both APD and EAP indexes are closely correlated with precipitation during flood-prone season in China and precipitation rate over the East Asia-West Pacific region. The significant correlation area at 5% confidence level is mainly located from the southern area of the Yangtze River valley to the ocean around southern Japan, and the former is a positive correlation and the latter is a negative one.
基金jointly supported by the National Natural Science Foundation of China (Grant No. 41305069)the Open Project Program of the Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science and Technologythe National Program on Key Basic Research Project of China (Grant No. 2010CB951904)
文摘The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） model.The model was driven by both natural and anthropogenic forcing agents.Major features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 20th Century Warming （20CW）,were generally consistent with the reconstructions.The simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 20CW to be unprecedented over the last millennium in the simulation.The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation.The simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental regions.Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales.The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different reconstructions.The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south.Both the zonal and meridional thermal contrast were enhanced during the MCA.This temperature anomaly pattern favored a stronger monsoon circulation.
基金This paper was supported by the ＂National Key Programme for Developing Basic Sciences＂ under Grant No. G2006CB403600Knowledge Innovation for the 3rd Period,Chinese Academy of Sciences under Grant No. KZCX2-YW-220the National Natural Science Foundation of China under Grant Nos. 40730952, 40575026, 40775051 respectively.
文摘Recent advances in studies of the structural characteristics and temporal-spatial variations of the East Asian monsoon （EAM） system and the impact of this system on severe climate disasters in China are reviewed. Previous studies have improved our understanding of the basic characteristics of horizontal and vertical structures and the annual cycle of the EAM system and the water vapor transports in the EAM region. Many studies have shown that the EAM system is a relatively independent subsystem of the Asian- Australian monsoon system, and that there exists an obvious quasi-biennial oscillation with a meridional tripole pattern distribution in the interannual variations of the EAM system. Further analyses of the basic physical processes, both internal and external, that influence the variability of the EAM system indicate that the EAM system may be viewed as an atmosphere-ocean-land coupled system, referred to the EAM climate system in this paper. Further, the paper discusses how the interaction and relationships among various components of this system can be described through the East Asia Pacific （EAP） teleconnection pattern and the teleconnection pattern of meridional upper-tropospheric wind anomalies along the westerly jet over East Asia. Such reasoning suggests that the occurrence of severe floods in the Yangtze and Hualhe River valleys and prolonged droughts in North China are linked, respectively~ to the background interannual and interdecadal variability of the EAM climate system. Besides, outstanding scientific issues related to the EAM system and its impact on climate disasters in China are also discussed.
文摘Research into the diagnostic methods and patterns of traditional East Asian medical （TEAM） systems of practice such as acupuncture and herbal medicine face certain challenges due to the nature of thinking in TEAM and the subjective basis of judgments made in practice. The TEAM-based diagnosis can take into account various findings and signs such as the appearance of the tongue, palpable qualities of the radial pulses, palpable qualities and findings on the abdomen, the complexion of the patient and so on. Both diagnostic findings and the patterns of diagnosis cannot be assumed to have objective bases or to be causally related to the complaints of the patient. However, the diagnoses of TEAM based acupuncture and herbal medicine have tended to look at pictures of the whole patient and rather than focus on a particular symptom, they have looked across a myriad of signs and symptoms to decide or identify the ＇pattern＇ of diagnosis according to the theory in question. Although open for selective and subjective biases each diagnosis pattern always comes with a prescribed treatment tailored to the pattern. Further, the same research requirements needed for the validation of the diagnoses are needed also for these clinical observations and judgments. Hence, it is necessary, albeit challenging for research on TEAM diagnoses to first address these issues before proceeding to more complex investigations such as the development of instruments for making diagnostic observations, instruments for forming diagnostic conclusions or studies investigating the physiological bases of the diagnostic patterns. Preliminary work has started and instruments have been made, but we suggest that any instrumentation must necessarily be first validated by matching of the calibrated or scaled observations or judgments to observations made and agreed upon by relevant experts. Reliability of all observations and judgments are needed before any other tool, technology or more advanced approach can proceed and also whenever the natural system of diagnosis-treatment is applied in clinical trials. In this paper the authors highlight the core problems and describe a step wise process for addressing them.
文摘利用850 hPa的纬向风异常建立一个逐候东亚-太平洋(East Asian Pacific,EAP)型指数,研究其季节内演变特征,发现东亚-太平洋型经向波列是东亚夏季风季节内变化的主要模态。其演变过程为:扰动首先出现在北太平洋中部,并通过正压不稳定过程从基本气流中获得能量而发展,在高层罗斯贝波能量向南频散,激发热带对流异常和赤道罗斯贝波,并相互锁相,因赤道罗斯贝波受β效应影响而共同向西移动。热带对流和环流异常在菲律宾附近达到最强,此时在东亚沿岸出现经向三极型波列,此后中低纬度异常继续向西北方向移动,使降水异常在长江流域能维持较长时间。东亚-太平洋型在东亚发展和维持有以下原因:首先,菲律宾暖水上空的对流和低层环流之间存在正反馈;其次,由于海陆热力差异导致暖大陆和冷海洋之间存在特殊的纬向温度梯度和北风垂直切变,东亚-太平洋型在经向上有向北倾斜的斜压结构,能通过斜压能量转换从平均有效位能中获得能量,同时,也能从经向温度梯度的平均有效位能中获得能量。
