EDITOR’S NOTE: It has been 40 years since the Democratic Reformabolishing feudal serfdom in Tibet was carried out in 1959. What haschanged, especially in the past 20 years of the reform and opening proqram introduced...EDITOR’S NOTE: It has been 40 years since the Democratic Reformabolishing feudal serfdom in Tibet was carried out in 1959. What haschanged, especially in the past 20 years of the reform and opening proqram introduced nationwide by the Central Government? A recent surveyof rural areas Provides an answer to this question.展开更多
Introduction.The study of catastrophic events that affected past marine ecosystems provides us the unique opportunity to establish models which can be applied to ongoing environmental changes and to understand future ...Introduction.The study of catastrophic events that affected past marine ecosystems provides us the unique opportunity to establish models which can be applied to ongoing environmental changes and to understand future evolution of the biotas.The growing interest of the society for the ongoing and potential future environmental changes attests for the value represented by the analysis of past climatic changes.In the case of the Toarcian Oceanic Anoxic Event(T-OAE,Early Jurassic;~182 Ma),a dramatic change of marine ecosystems related to massive extinction has been documented in several areas around the world.The Pliensbachian–Toarcian transition and the T-OAE are two global episodes recording worldwide palaeoenvironmental perturbations(Jenkyns,1988;Jenkyns and Clayton,1997;Hesselbo et al.,2007).The end of the Pliensbachian regression is followed by a transgression occurring in the Early Toarcian(Haq et al.,1987;de Graciansky et al.,1999).This transgression was also coeval with a widespread deposition of black shales(Jenkyns,1988),a global warming(Garcia Joral et al.,2011;Korte and Hesselbo,2011;Suan et al.,2011),and perturbations of the carbon cycle indicated by a negative carbon isotopic excursion(CIE)documented in both marine and terrestrial material(Jenkyns and Clayton,1986;Schouten et al.,2000;Hesselbo et al.,2007;Al-Suwaidi et al.,2010;Caruthers et al.,2011;Izumi et al.,2012;Reolid,2014).展开更多
Climate extremes and changes in eastern China are closely related to variations of the East Asian summer monsoon and corresponding atmospheric circulations.The relationship between frequencies of temperature and preci...Climate extremes and changes in eastern China are closely related to variations of the East Asian summer monsoon and corresponding atmospheric circulations.The relationship between frequencies of temperature and precipitation extremes in China during the last half century is investigated using Singular Value Decomposition analysis.During 1980-1996,there was a typical pattern with fewer hot days and more precipitation extremes in the northern part of eastern China,and more hot days and fewer precipitation extremes in the southern part.This geographic pattern tended to reverse after 1997,with fewer hot days and more extreme precipitation days south of the Yangtze River and vice versa to the north.Differences in atmospheric circulation between the former and latter periods are presented.We conclude that a mid-level anomalous high/low,upper-level anomalous easterlies/westerlies over the north/south of eastern China,a weakened East Asian summer monsoon and associated upper-tropospheric center of cooling(30°N,110°E) are all favorable for the changes in frequencies of temperature and precipitation extremes.展开更多
文摘EDITOR’S NOTE: It has been 40 years since the Democratic Reformabolishing feudal serfdom in Tibet was carried out in 1959. What haschanged, especially in the past 20 years of the reform and opening proqram introduced nationwide by the Central Government? A recent surveyof rural areas Provides an answer to this question.
基金This is a contribution of the IGCP-655 project of the IUGS and UNESCO.
文摘Introduction.The study of catastrophic events that affected past marine ecosystems provides us the unique opportunity to establish models which can be applied to ongoing environmental changes and to understand future evolution of the biotas.The growing interest of the society for the ongoing and potential future environmental changes attests for the value represented by the analysis of past climatic changes.In the case of the Toarcian Oceanic Anoxic Event(T-OAE,Early Jurassic;~182 Ma),a dramatic change of marine ecosystems related to massive extinction has been documented in several areas around the world.The Pliensbachian–Toarcian transition and the T-OAE are two global episodes recording worldwide palaeoenvironmental perturbations(Jenkyns,1988;Jenkyns and Clayton,1997;Hesselbo et al.,2007).The end of the Pliensbachian regression is followed by a transgression occurring in the Early Toarcian(Haq et al.,1987;de Graciansky et al.,1999).This transgression was also coeval with a widespread deposition of black shales(Jenkyns,1988),a global warming(Garcia Joral et al.,2011;Korte and Hesselbo,2011;Suan et al.,2011),and perturbations of the carbon cycle indicated by a negative carbon isotopic excursion(CIE)documented in both marine and terrestrial material(Jenkyns and Clayton,1986;Schouten et al.,2000;Hesselbo et al.,2007;Al-Suwaidi et al.,2010;Caruthers et al.,2011;Izumi et al.,2012;Reolid,2014).
基金supported by the Key Project of the National Eleventh-Five Year Research Program of China (2007BAC29B06)China’s National Key Science Program for Global Change Research (2010CB950504)+1 种基金the National Basic Research Program of China (2009CB42140 and 2012CB956200)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05090100)
文摘Climate extremes and changes in eastern China are closely related to variations of the East Asian summer monsoon and corresponding atmospheric circulations.The relationship between frequencies of temperature and precipitation extremes in China during the last half century is investigated using Singular Value Decomposition analysis.During 1980-1996,there was a typical pattern with fewer hot days and more precipitation extremes in the northern part of eastern China,and more hot days and fewer precipitation extremes in the southern part.This geographic pattern tended to reverse after 1997,with fewer hot days and more extreme precipitation days south of the Yangtze River and vice versa to the north.Differences in atmospheric circulation between the former and latter periods are presented.We conclude that a mid-level anomalous high/low,upper-level anomalous easterlies/westerlies over the north/south of eastern China,a weakened East Asian summer monsoon and associated upper-tropospheric center of cooling(30°N,110°E) are all favorable for the changes in frequencies of temperature and precipitation extremes.
