杜甫诗歌具有广义的史学价值.杜甫晚年飘泊诗作的相关描述,较为真实而又全面地反映了唐代陇、蜀、荆、湘沿途城市的气候特征.唐代秦州秋阳杲杲,秋雨迷蒙,秋霜凛冽,秋月凄清,同谷岁暮则雨多雪盛,偶见冬虹;成都四季分明,冷热适中,然时有春旱、夏洪发生;夔州夏秋毒热,巫山雾瘴、云雨、霜雪、雷电变幻莫测;荆州及湖湘东南一带春季早暖,夏季酷热多雨、易发洪水,秋季前热后凉,冬季冷热不均.唐代陇、蜀、荆、湘沿途城市的气候与今天上述各地情况基本相符,杜甫夏秋叹热莫过于夔州与潭州,亦与今天的重庆和长沙同列全国"火炉"城市地位相当.另据杜诗所叙剑门蜀道腊月山花开放,通泉冬季蚊蚋活跃,成都四月黄梅成熟,戎州、泸州六月盛产荔枝,江陵正月嫩荷抽叶、飞燕营巢,潭州正月蜂鸣密林、燕舞江滨,湘潭二月南风蒸地、春热黄昏等情况,唐代陇、蜀、荆、湘一带的年平均气温似应高于今天.

The characteristics of warm/cold fluctuation for Northern Hemisphere (NH) and China during the past 2000 years were analyzed using the proxy-based temperature change series published recently. The duration of centennial warm periods before the 20th century and the difference between the warmth of the 20th century and the centennial warm periods that occurred prior to the 20th century were also investigated. The conclusions are summarized as follows: (1) Most of proxy-based NH temperature series show that the warm climate occurred in the periods of AD 1-270, 841-1290 and 1911-2000. In general, it was cool with multi-decadal temperature fluctuations from 271 to 840, and cold from 1291 to 1910. These centennial periods of warm/cold fluctuation over NH are corresponding to the Roman Warm Period (the 1st century BC to the mid-4th century AD), Dark Age Cold Period (the end of 4th century to the early of 10th century AD), Medieval Warm Period (the mid-10th century to the end of 13th century AD), Little Ice Age (the 15th to 19th century) and Warming Period in the 20th century illustrated by Lamb respectively. But they have different durations between the NH centennial warm/cold periods and those Warm/Cold Periods identified by Lamb. (2) The duration and amplitude of regional centennial phases of warm/cold fluctuation are different in China, but the timing of centennial periods of warm/cold over whole China, i.e. warm in AD 1-200, 551-760, 941-1300, 1901-2000 and cold in the others, which are consistent with that observed in NH approximately. (3) Most of proxy-based NH temperature change series show that the warmth in Medieval Warm Period is at least comparable to that during the Warming Period in the 20th century. The warmest 100-year and 30-year (i.e., warm peak duration) for whole China occurred in the periods of 941-1300 during the past 2000 years, which are slightly higher than in the 20th century respectively. Moreover, the temperature anomalies in the warmest 100-year and 30-year for whole China that occurred in the periods of 571-760 and 1-200 are comparable to and a little lower in the 20th century respectively.

根据近年国内外相关研究结果,分析了北半球与中国过去2000 年冷暖变化的阶段性,辨识了百年尺度暖期的起讫年代及其与20 世纪温暖程度的差别。结果表明:(1) 最近新建的多数北半球温度变化序列显示公元1-270 年温暖;271-840 年冷暖相间,但总体偏冷;841-1290年温暖;1291-1910 年寒冷;1911 年以后再次转为温暖;这些冷暖阶段虽分别与Lamb 指出的罗马暖期(约公元前1 世纪-4 世纪中期)、黑暗时代冷期(约4 世纪末-10 世纪前期)、中世纪暖期(约10 世纪中期-13 世纪末)、小冰期(约15-19 世纪) 以及20 世纪增暖大致对应,但各阶段的起讫时间与Lamb确定的时段存在一定差别。(2) 尽管过去2000 年冷暖变化过程及其变幅大小在中国境内各个区域间并不完全一致,但从全国平均看,中国与北半球百年尺度的冷暖波动阶段基本一致,仅起讫年代存在一定差异;其中公元1-200 年、551-760 年、941-1300 年及20世纪气候相对温暖,其他时段则相对寒冷。(3) 多数序列显示中世纪期间北半球的温暖程度至少与20 世纪相当。中国941-1300 年间的最暖百年和最暖30 年(暖峰) 的温度也略高于20 世纪,551-760 年间的最暖百年与20 世纪基本相当,但1-200 年间最暖百年的温暖程度则较20 世纪略低。

The extreme cold winter events were defined as the ones with the occurrence probabilities lower than the tenth percentile of the probability density function, based on the observed temperature of winter and January in southern China since 1951. The impacts (including freezing of rivers/lakes, widespread snow/ice storms, and cold damages to subtropical/tropical crops) of these extreme cold winter events occurred since 1951, which were adopted to reconstruct the chronology of extreme cold winter events derived from Chinese documents in southern China during 1600-1950. The most frequent occurrences of extreme cold winter events were observed during 1650-1699, 1800-1849 and 1850-1899, with frequencies twice as many as that in 1950-1999. The frequencies of extreme cold winter events in 1600-1649 and 1900-1949 were a little higher than those in 1950-1999. In contrast, the frequencies of extreme cold winters during 1700-1749 and 1750-1799 were close to those in 1951-1999. Moreover, the occurrence of extreme cold winter events happened year by year or every other year in most of cases. Meanwhile, the intensities of some historical cold events exceeded those of the coldest winter events since 1951.

以南方地区及全国的冬季与1 月气温观测记录为基础,采用事件发生概率密度函数小于10%的标准确定1951 年以来的极端冷冬事件；根据历史文献中的寒冷事件及其灾害影响记载,采用古今极端冷冬事件影响程度对比的方法建立了1600-2010 年间的极端冷冬事件年表。分析表明：极端冷冬发生频率存在明显的阶段性变化,其中1650-1699 年、1800-1849 年及1850-1899 年是过去400 年极端冷冬发生最为频繁的时段,其发生次数达1950-1999 年的2 倍,1600-1649 年及1900-1949 年较20 世纪后半叶略多, 而1700-1749 年及1750-1799 年则与1950-1999 年相当。此外,极端冷冬事件具有连发或隔年再发特征。同时,20 世纪50 年代以来最严重冷冬事件的寒冷程度并没有超出历史时期曾经出现过的事件。

For the temperatural properties of the climate in Tang Dynasty, a famous one inhistory of China, there are different opinions upon the climate in Tang dynasty.The subtropical species Plum trees had been planted in the imperial garden in thecapital Chang'an, which was managed elaboatly and was used as blooming admiration.So, even though it is originally growing as one of subtropical species, its climaticrestrictive condition had been changed by gardeners' management when it was plantedas a blooming-admiration species in the imperial garden at the capital Chang' an.The same samples, Plum trees were planed in northern area, can also be found inYuan and Qing Dynasties in Kaifeng, Beijing, Jinan and Anyang. If the gardenedPlum could serve as indicator for warm climate, we had to admit that the climate inYuan and Qing Dynasties were also warm. Orange tree is also a subtropical plantand appeared in the imperial garden in Chang' an. By comparing the Orange treedistribution (economically, not as an admiration)with river freezing phenomena, we canfind that the rivers in the distribution zone of Orange tree are not iced annually. Butthe rivers nearby the capital Chang' an in Tang dynasty were recorded to freeze andunfreeze in winter and next spring every year. It is clear that the cold winter did notsuit Orange tree living. That means the elaborate management on the warm-likespecies have changed the local condition, which made the species lived in a morenorthern place. Such species loses their rationality as an indicator for natural climaticcondition.Tame elephant contributed by some southern kingdoms and existed in Chang' an,is other evidence used as indicator for warm climate in Tang Dynasty. Beforeexplaining its climatic significance, another analogy can be viewed, which comes fromQing Dynasty. There was a special office agency in Capital Beijing, which main dutywas to manage and feed unusual animals, such as hoe elephant In that bine,thetame elephant serviced in ceremonial occasions.So we would fall into self-contradictionwhen we admit tame elephant is a warm indicator, because Qing Dynasty was in theLittle Ice Age and Beliing locates more northern than Chang' an. This is anotherexample that human activities change the climatic condition of some species. Therefore,such species under human control are impossible to be used as climatic indictor.All of the recorded cold eventS in bine series (such as heavy snow, abnormalsnowing and frosting date, the sea water icing and so on) reveal that theyconcentrated in the second half of Tang Dynasty (760' s- 900's). An accumulatedcurve is used to shows the feature. For the reason that it could be other facts thatcause the concentration of cold events, for example, the record missing in some period,a warm event accumulated curve is used to examine above phenomenon. The warmcurve shows that warm events decline after the middle of 8th century, and processesan opposite feature with the cold event curve. It can be confirmed that theconcentration of cold events means that the climate have changed to cold since themiddle 8th century. There was a cold trough at 800' s, in which some decades heldcold feature similar to that of the Little Ice Age, for example the sea water lcing innorthern pan of Jiangsu province.Sea water icing in northern part of Jiangsu Provinceindictes a severe cold winter. In the winter 1935-1936, the sea water in Bobai seawas frozen. This winter is so cold that it is listed as a second coldest winter in the20th century, but no report said the sea water icing happened in the northern part ofJiangsu province. So, in historical bines, the cold events, sea warer icing in thenorthern pall of Jiangsu Province, were only found in Tang Dynasty and Ming toQing Dynasties (same as the Little Ice Age) of the last millennium. Otherpheonological evidence of a cold climato is from a Japanese Shaman's travels.

本文就历史文献记载的资料详细讨论了唐代气候冷暖两方面的证据。从现有支持气候温暖的证据来分析,它们难于确定相应的气候限制因子,并且类似的证据存在于不同的气候条件下。从有关的寒冷资料分析,唐代气候至少可分为两大阶段,8世纪50年代以前大体与现代相差不大,但8世纪60年代以后气候变冷,某些时段寒冷的特征可与明清小冰期相似。

Weng Xincun Diary conveys the most detailed weather records among all the known historical diaries，which provides valuable contemporary reports of dust weather in the middle of 19th century in Beijing.Firstly，this paper extracts every sand dust record scattered in this diary.By analyzing the sand dust records statistically，this paper reconstructs the sand dust weather condition in Beijing in the middle of 19th century.Whats more，the detailed dust records provide the possibility to recognize the subdivision of the sand dust weather in historical time，the sandstorm，sand blowing and the floating dust weather.As the present research has no official classification methods to classify the dust weather from historical records，this paper explores a way to classify the different types of sand dust weather.The results show that: (1)the annual average sand dust days of Beijing at that time is up to 31.36 times，which is higher than the annual average sand dust days during the last 60 years.(2)The classification of different types of sand dust weather shows that the composition of sandstorm，sand blowing and floating dust weather is similar to that of today，the inner annual distribution of sand weather days in the middle of 19th century also shares similarity to today's data.(3)The main difference lies in the season distribution of sand weather: In the 1850s，the sand weather occurrence in summer is higher than today by 46％，the sand weather occurrence in winter however，is lower by 15％ compared with the present status.This result may show that the seasonally distribution of sand dust weather changes greatly from ancient time.(4)The interannual variability of sand weather is quite obvious in the 1850s，and this paper shows that the local precipitation acts as an important role in the annual variability of sand dust weather.

《翁心存日记》是迄今为止发现的记录天气现象最为详细的历史天气日记，保留了难得的19世纪中叶北京的沙尘天气记录。归纳了对历史文献记录中的沙尘天气进行分类的方法，通过《翁心存日记》，重建了19世纪中叶北京沙尘天气情况。分析发现当时北京年平均沙尘日多达31.36天，高于近60年来北京沙尘天气的平均水平。而19世纪中叶的北京沙尘天气中扬沙、浮尘和沙尘暴天气的构成和现代基本相似，年内分布特征也较相似。但19世纪中叶夏季沙尘比例较现代明显偏多46％，而冬季沙尘比例仅为现代比例的75％，这说明古今间沙尘天气的季节分布可能存在较大差异。另外，19世纪的沙尘天气同样存在明显的年际变化，且本地降水是影响年际变化的因素之一。

依据清代《翁同龢日记》中天气 状况的描述,整理出公元1860-1898年间逐月的沙尘天气日数, 基于记录完整月份的沙尘天气日数,统计分析了公元1860-1898年北京沙尘天气日数的平均状况和变化特征。分析发现公元1860-1898年,北京年 均沙尘天气记录为10．4天,即使不考虑与现代观测记录标准的差别,亦肯定高于1990年代7．7天/年的平均频次;春季是沙尘天气的高发季节,其占全年 沙尘日数的百分比达到70％, 其中4月和5月两个月的日数接近53％;其次为冬季,占20％。与公元1961-2000年相比,公元1860-1898 年的春季沙尘天气日数百分比偏高10．9％,沙尘天气在春季的集中程度明显偏高。公元1860-1898年间,年沙尘日数和春季沙尘日数均呈波动减少之 势;研究时段内,共出现23次2天以上连续(或持续)的沙尘天气过程, 最长的一次持续了4天。这些发现将有益于研究气候变化对沙尘天气影响和分析北京沙尘天气的演变规律。

In the current research on climate changes it is a hot topic to study the changes of extreme climatic events during historical periods. In this paper, based on the reconstructions from multiple proxy types including historical documents, tree-rings, ice cores and lake sediments in the published literature of the recent 20 years, we summarized the characteristics of changes of extreme climate events during the past 2000 years in China. The analysis shows that: (1) During the cold periods of 1500-1900 and 220-580, there appeared extremely cold winters that were even colder than the cold winters in the years after 1950, and there appeared hot summers with daily highest temperature exceeding record high of the years in the 20th century as well. In the past 1600 years, the cold summer events in Northeast of China mainly occurred during the period of 1400-1900. (2) In the eastern monsoon region of China, the extreme drought events prevailed during the periods of 301-400, 751-800, 1051-1150, 1501-1550 and 1601-1650, the extreme flood events often occurred during the periods of 101-150, 251-300, 951-1000, 1701-1750, 1801-1850 and 1901-1950, and for the period of 1551-1600, coexisting extreme drought and extreme flood events occurred most frequently. The frequency of persistent extreme drought was higher during the 7th-8th century, 12th-14th century and late-15th century to mid-17th century; the frequency of sustaining extreme flood was higher during the 10th-11th century and after the mid-17th century. The time intervals of extreme drought/flood events are different in North China, Yangtze and Huaihe River Valley and south of Yangtze River. In addition, the notable extreme drought events, such as "Chong Zhen Drought" in the Ming Dynasty, and "Ding Wu Famine" in the Qing Dynasty, were recognized. (3) In the arid region of Northwest China, the extreme drought events mainly occurred during the periods of 1471-1520, 1581-1650, 1711-1760, 1811-1860 and 1921-1970. 1710s was the most severe drought decade during the past 1000 years. However, due to the very limited climate proxy data for this region, the primary characteristics of complete change process of the extreme events were difficult to evaluate. (4) Although drought frequently occurred in southwest of China during the early 21th century, the extreme drought events as severe as the one in Sichuan and Chongqing in 2006 occurred many times during the historical periods.

历史时期极端气候事件变化是当前气候变化研究的热点领域。本文根据近20 年这一研究领域的主要文献，对中国过去2000 年极端气候事件变化特征进行了梳理和总结。已有认识表明：① 在1500-1900 年和220-580年等气候寒冷期，中国不但多次出现过较1950 年以后所出现的极端冷冬更为显著的寒冷事件，而且其间的相对温暖时段也出现过日最高气温超过20 世纪极端记录的炎夏。② 在中国东部季风区，在公元301-400、751-800、1051-1150、1501-1550 和1601-1650 年极端干旱多发；101-150、251-300、951-1000、1701-1750、1801-1850 和1901-1950 年极端大涝多发；1551-1600 年则是极端干旱与大涝并发最为频繁的时段。7-8 世纪、12-14 世纪和15 世纪后期-17 世纪中期多发极端连旱；10-11 世纪及17 世纪中期以后，多发极端连涝。华北、江淮和江南3 个地区的极端干旱和大涝事件多发时段存在差异；此外，历史极端连旱事件如“崇祯大旱”和“丁戊奇荒”等也得到辨识。③ 在西北干旱区，极端干旱主要集中发生在1471-1520 年、1581-1650 年、1711-1760 年、1811-1860 年和1921-1970 年等5个时段，其中18 世纪10 年代可能是过去千年极端干旱最严重的年代。④ 在西南地区，虽然21 世纪初旱灾频发，但与2006年川渝特大干旱相仿的事件在史上也曾多次发生过。