依据近年发表的新成果,对中国过去千年干湿的年至百年尺度变化特征进行了总结梳理与对比分析,综合评估了20世纪干湿变幅的历史地位。主要结论是：① 根据历史文献记载重建的东中部各区干湿序列在1400年以后均达高信度,但其前因存在记录缺失,仅有半数时段的重建结果达高信度。在东北及内蒙古东部,根据不同地点湖沼沉积物记录揭示的区域干湿百年尺度变化特征在多数时段不一致。在西部的黄土高原、河西走廊、新疆中北部、青藏高原东北部和东南部等地区,利用不同地点树轮资料重建的干湿序列显示的干湿变化特征在区内一致性高。② 过去千年中国各地干湿变化均存在显著的年际、年代际和百年尺度周期。其中准2.5 a、60~80 a和110~120 a等尺度的周期为所有地区共有;3.5~5.0 a、20~35 a等尺度周期则主要发生在东北、东中部地区、黄土高原和青藏高原;而准45 a周期则只发生在东北和东中部地区（均超过90%信度水平）;各区域间的干湿变化位相并不同步。③ 尽管已发现青藏高原东北部20世纪很可能是过去3000 a最湿的世纪之一,但其他大多数区域的重建结果显示：20世纪的干湿变幅在年代际尺度上均未超出其前各个时段的变率范围。

Based on the latest hydroclimatic reconstructions in peer-reviewed scientific journals, we summarize the multi-scale pattern on hydroclimatic changes and assess whether or not the variability of the 20th century is unusual in the context of the past millennium for different regions of China. The main conclusions are as follows: (1) In the central-eastern China, the dry/wet series reconstructed from historical documents after 1400 have high confidence level, while before 1400, the reconstructions only in half of the period have high confidence due to the shortage of records. In northeastern China and eastern Inner Mongolia, centennial-scale reconstructions from lake sediments at multiple sites are in low agreement in most of periods. In Loess Plateau, Hexi Corridor, central to northern Xinjiang, northeastern and southeastern Tibetan Plateau, hydroclimatic reconstructions from tree rings have robust agreement within the same region. (2) All sub-regions of China show significant cycles with 90% confidence level at inter-annual, inter-decadal and centennial scales. The cycles of 2.5 a, 60-80 a and 110-120 a are detected over all the regions, while the cycles of 3.5-5.0 a and 20-35 a mainly occur in the Loess Plateau, Tibetan Plateau, northeastern and central-eastern China. The cycle of quasi-45 a only occurs in northeastern and central-eastern China. Moreover, the hydroclimatic changes are out of phase in different regions. (3) The 20th century is one of the wettest centuries in the past 3000 years in northeastern Tibetan Plateau. However, most series from other regions show that the inter-decadal hydroclimatic variability of the 20th century does not exceed the amplitude of natural variability, which had ever occurred during the past millennium.

利用马尔康市1954—2019年逐月气温、降水量实测资料,基于气候倾向率、突变检验、信噪比检验、周期估算等方法对本区气候变化、旱涝灾害演变特征进行分析,并借助ADF检验、Granger因果关系分析来验证旱涝灾害的驱动因子。结果显示:马尔康市年均气温、年降水量均呈显著上升趋势,气候有暖湿化倾向;多年平均降水量以16.29 mm/(10 a)的速率增加,以夏季、秋季增多明显,春季增幅最小;2001年为本区气候突变点,气温突变后的旱涝灾害呈增多态势,极端洪涝事件更为频繁,2015—2019年是一次重大洪涝事件;太阳黑子活动与ENSO事件皆为降水量变化的Granger原因。厄尔尼诺与南方涛动事件(ENSO)事件与马尔康地区的旱涝灾害在6.6 a上有较同步的共振周期,滞后期为2 a的ENSO事件是旱涝变化的主要诱因之一。ENSO事件在年尺度上为区域旱涝预警提供了重要理论支撑。

The characteristics of climate change and evolution of drought and flood disasters in Maerkang City were examined through tests of climate tendency rate,abrupt change,signal-to-noise ratio,and cycle estimation based on the measured data of monthly temperature and precipitation from 1954 to 2019.The driving factors of drought and flood disasters were verified via ADF test and Granger causality analysis.The average annual temperature and annual precipitation showed a significant upward trend,and the climate tended to be warm and humid.The average annual precipitation increased at a rate of 16.29 mm/10a,obvious in summer and autumn while to the minimum in spring.Climate changed abruptly in 2001,after which the drought and flood disasters increased and the extreme flood events became more frequent.The years from 2015 to 2019 witnessed a large flood event.Both sunspot activity and ENSO(El Nin~o-Southern Oscillation) events are Granger causes of precipitation variation.The ENSO events and the drought and flood disasters have synchronous resonance period in 6.6 years.The ENSO event with a lag period of two years is one of the main causes of the changes in drought and flood disasters.ENSO events provide an important theoretical support for regional drought and flood warning on an annual scale.

利用阿依拉山采样点的树木年轮标准化年表与川西高原的马尔康和红原前一年10月至当年9月的气候资料进行相关分析。结果表明， 马尔康7月平均气温与阿依拉山采样点的树木年轮生长有较好的相关性， 相关系数达0.644。利用树轮年表重建了1597-2005年马尔康7月平均气温序列， 方差解释量为41.5%， 经过检验， 转换方程稳定可靠。检测409年重建气温序列的周期信号， 发现重建序列存在3～4年、 5～9年、 21～28年和56～76年的周期振荡， 其中较短的年际周期的强振荡期均出现在21世纪， 中周期的强振荡期主要出现在最后一次小冰期， 而长周期则在工业革命之前能量最强。

Single correlation calculation indicated that the correlation were significant among tree-ring chronologies of Ayilashan and temperature in July at Maerkang and Hongyuan stations in West Sichuan, Considering the hysteresis of temperature about growth of tree, a average temperature series in July of 1597-2005 at Maerkang station was well reconstructed and its explain variance was 41.5% by means of the tree-ring chronology series. It was verified that the reconstructed temperature was reliable by leave-one-out. Some results obtained by analyzing the 409-year reconstructed temperature series are as follows: periods of temperature in July have 3～4， 5～9， 21～28  and 56～76 years. Strong energy of short periods have happened at high temperature age, middle one, in little ice age, and  long one, before the industrial revolution.

利用四川省松潘县西部牟尼沟二道海采集的树木年轮样本， 建立了该地区173年树木年轮年表序列， 并依据响应函数、 相关与偏相关方法， 分析了该年表与气象要素之间的关系， 发现该年表对5月降水较敏感, 并由此重建了1837-2009年松潘高原地区5月降水序列。结果表明， 1837年以来松潘高原地区先后经历了5个偏湿阶段和3个偏干阶段； 以重建的1971-2000年30年气候平均值为基准， 在重建的16个气候时段中1961-1990年是降水最少的气候时段， 而1837-1860年则是降水最多的气候时段； 降水发生了多次正负突变， 比较可靠的突变点出现在1863年前后、 1874年前后、 1890年前后、 1904年前后、 1958年前后和1994年前后； 重建序列周期变化明显， 存在2~4年、 16年和32~50年为主的周期振荡。

The tree-ring standardized chronology series (TRSC) in 173 years was established based on the tree-ring width data of Songpan Plateau. The correlations between the TRSC and meteorological elements were analyzed using the response function, linear correlation and partial correlation methods. The result shows that the TRSC responses to precipitation  sensitively in May. And the precipitation in May  in Songpan Plateau was reconstructed. Furthermore, the change characteristics of precipitation were analyzed. The results show that there are 5 wet periods and 3 dry periods of the precipitation in May in Songpan Plateau in the past 173 years. During the 16 reconstructed climate-periods, it was the lowest for precipitation in 1961-1990, while 1837-1860 was the highest. The reconstructed series show abrupt change at many times, with credible abrupt point appearing in 1863, 1874, 1890, 1904, 1958 and 1994.It is found that the periodic cycles about 2~4 years, 16 years and 32~50 years are significant.

通过在祁连山东部互助地区采集的油松样本,建立标准树轮（STD）年表,重建该地区近188 a上年8月到当年6月的降水,解释方差为48.8%。根据重建结果,历史上的湿润时期有1850s—1860s、1930s末—1950s、1970s—1990s以及2000s;干旱时期有1830s—1840s、1900s、1920s,其中1920s的干旱在北方大范围内普遍存在。根据本文重建结果与周围地区降水和PDSI重建比较,发现该地区降水变化与贺兰山地区干湿变化最为相近,尤其是1940s以前,在1940s之后与青海省德令哈和祁连山中西部地区的重建结果更为相似。因此推测,祁连山东部地区在1940s前后受不同的气候类型主导。

A tree-ring width chronology was presented based on Pinus tabulaeformis tree-ring samples from the Eastern Qilian Mountains, China, and a precipitation series for previous August to Current June in the Eastern Qilian Mountains during 1821-2008 were reconstructed. The reconstructed precipitation data can explain 48.8% of the actual precipitation variance during the recent 118 years. During the period, persistently wet periods were found in 1850s-1860s, the end of 1930s-1950s, 1970s-1990s and 2000s; and persistently drought periods were found in 1830s-1840s, 1900s, and 1920s. The drought epoch during 1920s was widespread in northern China. We compared this precipitation reconstruction sequence with the precipitation or PDSI reconstructions data, and found that the precipitation change in Eastern Qilian Mountains was the most similar with precipitation change in the Helan Mountains, especially during the period of 1820s-1940s. And after 1940s, the precipitation change in Eastern Qilian Mountains was more similar with precipitation change in Delingha of QingHai Province and MidWest of Qilian Mountains. So we supposed that the Eastern Qilian Mountains were probably controlled by different climate styles before 1940s and after 1940s.

利用1980-1997年垂直积分的整层水汽输送通量资料,分析了青藏高原东部及其邻近地区水汽输送的气候特征。结果表明,该区的水汽输送具有明显的季节变化特征:冬、春季的水汽主要来源于中纬度的偏西风水汽输送,夏季(7月)主要来源于孟加拉湾和南海,秋季(10月)主要来源于西太平洋地区。季风携带的南来水汽在高原东侧地区的进退比较缓慢,8月初北扩到40°N附近,10月中旬南退出30°N,其强弱和进退异常能影响极端旱涝事件的发生。来自南海、西太平洋地区的水汽输送对高原东部及其邻近地区的影响值得关注。

Climatological characteristics for large scale water vapor transport over the eastern part of the Qinghai-Xizang Plateau and its surroundings are investigated based on the vertically integrated water vapor flux from 1980 to 1997.It is found that in winter and spring,themoisture of the region is mainly from the middle-latitude westerly water transport;in summer(July),the moisture comes from the Bay of Bengle and the South China Sea,and in autumn the water vapor is from the west Pacific Ocean.The advance and retreat features of the moisture with southerlies over the region are slow.And the water vapor from south,whose abnormal action will affect the occurrence of floods and droughts,can advance no thwart to 40°N in August,and retreat southward to the south of 30°N in October.The enough attention should be paid to the influence of the water vapour transport from the South China Sea and the west Pacific Ocean on this region.

根据1961-2007年四川地区123个测站的逐日降水资料和NCEP/NCAR逐月再分析资料， 采用Z指数作为旱涝等级划分标准， 分析了四川地区旱涝出现的频率， 采用EOF、 REOF分析、 趋势分析、 滑动t检验以及小波分析等方法， 研究了四川地区旱涝灾害发生\, 发展的空间演变特征及时间变化趋势。结果表明, 该地区旱涝事件的空间分布可分为4个区, 分别是四川盆地东部区、 西部区、 川西南山地区和川西高原区。从时间变化趋势上看， 四川盆地东部区、 川西南山地区和川西高原区由偏旱逐渐向偏涝转变； 而四川盆地西部区由偏涝逐渐向偏旱转变。4个分区的周期振荡特征显著， 有明显的年际变化和年代际变化。夏季西太平洋副热带高压及南亚高压位置的南北变化、 高原季风的强弱变化分别对四川盆地东部区、 西部区及川西高原区的旱涝事件有显著的影响。