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1.
运用古气候参数方法对滇西北高原YXL剖面进行孢粉分析,结合定年数据,重建了该地区晚更新世晚期以来的植被变化和气候变化并与我国南方石笋记录等进行对比分析。研究表明:从大约31570cal.yrBP以来,滇西北高原总体经历了温凉偏干-冷干-略转暖湿-冷干-转暖增湿-冷干-转为暖湿-温和偏干-温凉偏干的气候变化历程,其间多有反复;YXL剖面孢粉记录与董哥洞、葫芦洞石笋记录在古气候变化大趋势上基本一致,对H2、H1、YD、MWP、LIA等气候事件反映明显;YXL剖面孢粉记录中全新世大暖期升温增湿的速度慢于石笋记录和冰芯记录,其干冷气候期持续时间较长,这些特点均与高原环境有关,并受到青藏高原的影响,具有一定的区域性意义。   相似文献   

2.
通过对青藏高原东北部共和盆地泥炭沉积的粒度与地球化学元素分析, 重建了区域全新世千年尺度的气候变化过程. 结果显示: 10.0~8.6 cal ka BP区域暖湿程度逐渐增加, 但在8.6~7.1 cal ka BP气候相对寒冷干燥, 7.1~3.8 cal ka BP 暖湿程度总体上为全新世最佳, 但也出现明显的气候波动, 3.8~0.5 cal ka BP气候向冷干方向发展, 0.5 cal ka BP以来气候又逐渐转向暖湿. 这一特征与中国东部季风区的气候变化有很好的一致性. 此外, 区域全新世气候变化过程中存在10次千年尺度的寒冷事件, 并与高原冰芯、 湖泊、 泥炭和风成沉积记录的古气候变化, 甚至与北半球高低纬度的气候变化都具有良好的可比性. 因此, 认为区域全新世气候变化具有"季风模式"与"千年尺度震荡"的双重特点.  相似文献   

3.
本文根据青藏高原东部若尔盖盆地RH孔的全面分析,讨论了青藏高原82.6万年以来的长期气候变化,共划分为23个阶段。基本特征为冷期持续时间要远远超过暖期,内部结构相对比较稳定,而暖期的内部次级波动要频繁得多。通过呼伦湖和固城湖岩芯研究,重建晚冰期以来的气候变化历史,新仙女木事件及全新世几次降温事件在两个湖泊中均有反映。统计了中国东部27个湖泊湖面波动资料,讨论了季风区环境变化的穿时性。  相似文献   

4.
通过对青藏高原崩勒溶洞石笋进行高精度的230 Th测年和C、O同位素分析,建立了中全新世7ka BP以来西藏昌都地区高分辨率的古气候变化记录。石笋C、O同位素记录揭示出,西藏昌都地区中全新世(约7ka BP)以来的气候演化大致可分为3个气候阶段:7000~4500aBP为暖期阶段,气候总体处于高温暖湿,伴随缓慢降温;4500~2300aBP为降温期阶段,出现持续降温,气候变得干旱;2300aBP至今为升温期阶段,气温及降水均出现波动上升。石笋C、O同位素记录的研究结果表明,中全新世以来研究区存在高温暖湿、快速降温干旱以及后期气候强烈震荡升温的气候过程。通过与董歌洞石笋同位素记录对比表明,崩勒溶洞石笋δ18 O同位素曲线变化的斜率、震荡幅度都要明显高于董歌洞石笋记录,揭示出青藏高原东部季风区的气候波动与全球性冷暖变化具有一致性,但高原石笋同位素记录对气候变化更加敏感。昌都石笋同位素反映的气候变化趋势与低纬地区夏季太阳辐射强度变化正相关,表明太阳辐射强度变化是高原季风影响区气候变化的重要驱动因素。  相似文献   

5.
祁连山敦德冰芯氧同位素剖面的古气候信息探究   总被引:10,自引:2,他引:10  
卫克勤  林瑞芬 《地球化学》1994,23(4):311-320
冰芯δ~(18)O剖面的古气候研究一直是基于大气降水同位素组成的温度效应,即冰芯δ~(18)O值与气温呈正相关关系。我国大气降水的同位素组成研究结果表明,在亚洲季风区,由于夏季风带来贫重同位素的暖湿气团,使得季风气候区夏季雨水的δs值低于冬季的δw值,δs-δw<0,正好和温度效应预测的相反。因此,我国季风气候区冰芯的δ~(18)O曲线主要反映古季风的盛衰进退,即冰芯的低δ~(18)O值对应的是夏季风盛行,气候转暖,降水量增加,夏季风前锋北移;冰芯的高δ~(18)O值则对应夏季风强度减弱,气候转冷,降水量减少,夏季风前锋南移。用上述季风气候模式解释敦德冰芯的百年、千年、万年三个不同时间尺度的δ~(18)O剖面,所得结果与已知的全新世古气候事件吻合。根据敦德冰芯δ~(18)O剖面提供的古气候信息,全新世大致可分成三段四期:10600-7100aB.P.为早全新世,与末次冰期相比,夏季风逐渐增强,气候转暖;7100-4000aB.P.为中全新世的前期,夏季风盛行,气候暖湿;4000-1700aB.P.为中全新世的后期,此时夏季风退缩,气候偏干冷;1700aB.P.至今为晚全新世,其间1700-700aB.P.夏季风强度  相似文献   

6.
全新世温暖期中低温事件的初步研究   总被引:24,自引:1,他引:23  
王开发 《第四纪研究》1990,10(2):168-174
在第四纪气候中,全新世是气候转暖期,尤其是全新世中期为其最暖期,然而在温暖期中,却普遍发现有短暂的降温时期,世界各地均有存在。根据中国全新世各地的孢粉植物群、动物化石、西部冰川消长、海面升降变化以及天文背景等研究证实,在中国全新世温暖期中,确实存在一次短暂的降温事件,并有其重要的地学意义。  相似文献   

7.
MIS 3晚期东亚季风强度和DO事件年龄   总被引:2,自引:0,他引:2       下载免费PDF全文
基于神农架山宝洞石笋(SB46)的9个230Th年龄和326个氧同位素数据,建立了末次冰期32.2~26.7kaB.P.和17.0~15.4kaB.P.的东亚季风降水序列。该序列和同一洞穴全新世石笋记录的对比发现,在MIS3晚期东亚季风区可能存在极强夏季风降水事件,相当于全新世季风强度,可能与岁差旋回太阳辐射及海陆水汽潜热释放增强有关。与葫芦洞石笋δ18O记录和格陵兰冰芯δ18O记录对比表明,东亚夏季风千年尺度气候振荡与高北纬地区海-气快速重组存在遥相关效应。山宝洞石笋年龄与葫芦洞石笋和格陵兰冰芯时标(SS09sea)在定年误差范围内基本一致,但山宝洞石笋与冰芯记录在DO事件的年龄、波形和持续时间上更为一致,不仅进一步说明了低纬季风气候与极地气温同步变化,而且有效地弥补了葫芦洞记录在这一时段的不足。  相似文献   

8.
泥炭记录的环境演变是过去全球变化(PAGES)研究的重要领域之一,分析了中国泥炭记录的古气候演化研究的区域范围,当前主要以东北哈尼、青藏高原的红原、神农架大九湖以及华南定南大湖四个位于东部季风区的研究工作最为集中。泥炭沉积高分辨率综合信息揭示了末次冰消期以来中国气候变化的时空特征:冷暖干湿变化既有一致性又表现出区域差异,末次冰消期东北地区、东部山地、华南地区都表现出冷偏湿的气候特点,而青藏高原却为冷偏干或凉偏干;Younger Dr-yas(YD)事件之后,全新世早期和中期青藏高原、东部山地、华南地区气候总体以温湿为主要特征,而东北地区有效降水减少,到全新世晚期,呈现出干旱的变化趋势。并对B~A事件,YD事件,8.2ka以及4.2 ka等重大气候突变事件研究工作进行了综述。最后指出今后应拓展与重建更多区域古气候环境变化序列的对比,加强泥炭沉积及环境指标的基础理论,重视和提高大气沉降泥炭档案以及气候变化背景下泥炭地碳循环机制等研究工作。  相似文献   

9.
中国泥炭记录末次冰消期以来古气候研究进展   总被引:1,自引:0,他引:1  
泥炭记录的环境演变是过去全球变化(PAGES)研究的重要领域之一,分析了中国泥炭记录的古气候演化研究的区域范围,当前主要以东北哈尼、青藏高原的红原、神农架大九湖以及华南定南大湖四个位于东部季风区的研究工作最为集中。泥炭沉积高分辨率综合信息揭示了末次冰消期以来中国气候变化的时空特征:冷暖干湿变化既有一致性又表现出区域差异,末次冰消期东北地区、东部山地、华南地区都表现出冷偏湿的气候特点,而青藏高原却为冷偏干或凉偏干;Younger Dryas(YD)事件之后,全新世早期和中期青藏高原、东部山地、华南地区气候总体以温湿为主要特征,而东北地区有效降水减少,到全新世晚期,呈现出干旱的变化趋势。并对B~A事件,YD事件,8.2 ka 以及4.2 ka等重大气候突变事件研究工作进行了综述。最后指出今后应拓展与重建更多区域古气候环境变化序列的对比,加强泥炭沉积及环境指标的基础理论,重视和提高大气沉降泥炭档案以及气候变化背景下泥炭地碳循环机制等研究工作。  相似文献   

10.
贵州荔波1200年来石笋高分辨率的古气候环境记录   总被引:4,自引:1,他引:3  
通过笔者对荔波龙泉洞L2石笋进行高精度的ICP-MS-~(230)Th测年和碳、氧同位素分析,建立了荔波地区1200 a BP来高分辨率的古气候变化的时间序列.研究结果表明.荔波地区1200 a BP以来石笋记录的季风气候经历了1200~1100 aBP(暖)、1100~940 aBP(冷)、940~840 aBP(暖)、840~700 aBP(冷)、700~450 aBP(暖)、450~300 a BP(冷)、300~200 a BP(暖)以及200~70 a BP(冷)等8个阶段百年尺度的干湿、冷暖波动,并在这些百年尺度的波动上又叠加了一系列数十年尺度的气候变化.石笋记录揭示了1200 a以来东亚季风气候的不稳定性,呈百年尺度(Gleissberg)的周期性变化.这些气候变化事件,与冰芯记录极为相似,反映低纬度地区百年尺度石笋记录的季风气候变化与高纬度及北极地区的气候变化具有极好的相关性,反映百年尺度石笋记录的季风降水主要受太阳辐射驱动、控制,而东亚季风的降水事件(或干旱事件)与太阳的辐射强度密切相关.石笋记录的百年尺度季风降水事件对于认识现代气候系统变化以及对未来十年-百年尺度的气候预测和演化的驱动机制,具有重要的科学意义.  相似文献   

11.
末次盛冰期华北平原古气候古环境演化   总被引:3,自引:0,他引:3       下载免费PDF全文
华北平原宁晋泊南王庄剖面的^14C和光释光年代测定表明宁晋泊地区在末次盛冰期有连续的湖相沉积。依据孢粉、碳酸盐、有机碳含量(TOC)及C/N值的高分辨率分析与综合判识,末次盛冰期并不是一个持续的干冷时期,而是存在从凉湿-冷偏湿-冷干的波动变化过程。其中早期明显降温事件,可以与Heinrich事件2(H2)对比,说明全球降温的同步性。本研究说明末次盛冰期(20-16ka BP),在全球气候变冷的背景下,存在一个冬季风不断加强夏季风逐渐变弱的过程。  相似文献   

12.
Climatic variations in China during the Quaternary have long been a question of debate. Considerable data now available support Professor Li Siguang's (J. S. Lee) suggestion that there were four glacial periods. In this later years the views of Professor Li have received support from more recent information demonstrating that a further glacial period and periglacial phenomena preceded the Boyang Period.During the Quaternary 3,500,000 years ago there were a number of climatic fluctuations in China, having an amplitude of over 10°C and a cycle of 104 to 105 years. Each fluctuation lasted from the onset of one glacial period to that of the next, encompassing a glacial period and an interglacial. Tab 1 provides a comparison between the glacial periods in China during the Quaternary and those in other regions of the world.  相似文献   

13.
东北地区以泥炭为信息载体的全新世气候变迁研究进展   总被引:1,自引:0,他引:1  
泥炭作为一种地质信息载体,在全球环境变化研究中起着越来越重要的作用.我国东北地区地处全球变化的敏感区,泥炭地研究的意义更为显著.笔者针对近年来东北地区泥炭地研究的多种成果,对该区全新世以来泥炭沉积和区域气候变迁历史进行了系统分析.得出:①东北地区泥炭有三次沉积高峰,分别始于早全新世、中全新世与晚全新世初期;②该区10000a以来大体上经历了冷湿-温暖适宜-凉湿-温暖偏干-冷干-寒冷略湿-变暖这样一个气候变迁过程.  相似文献   

14.
Based on the definition of Binary Tropical Cyclones (BTCs), the definition of influencing china binary tropical cyclones (ICBTCs) was proposed. During the BTCs period, if at least one of the two tropical cyclones causes precipitation over the mainland or one of the two largest islands-Hainan and Taiwan of China, the BTC is called ICBTC. Then, based on daily precipitation data and the tropical cyclone best track data during 1960-2017, this study analyzed the climatic characteristics of ICBTCs using the Objective Synoptic Analysis Technique (OSAT) and the above definitions. First, a total of 255 pairs of ICBTCs, which accounted for 60.6% of the total number of BTCs over the Western North Pacific, occurred with an annual average of 4.4. Annual frequency of ICBTCs showed a significant decreasing trend during 1960-2017. The longest duration of ICBTCs was 10 days, while durations concentrated in 1 day, 2 days and 3 days, accounting for 18.8%, 29.4% and 24.3%, respectively. In terms of geographical distribution, the ICBTCs mainly occurred over the range of 112°~138°E, 12°~30°N, with frequent zones in the oceans around the northern Philippines. In addition, both annual mean frequency and precipitation of the ICBTCs decrease from the southeast coast areas to the northwest inland regions, with severely-affected areas being the Taiwan Island, the Southeast Coast and the South Coast, and the most-severely-affected area being the Taiwan Island. Further analyses reveal that the average position of the two TCs on the maximum daily precipitation day during the ICBTCs period show an east-west distribution pattern, with the western TCs and the eastern TCs locating in the southwest wind water vapor channel of the East Asian Summer Monsoon and the warm-wet air flow of the southeast-wind on the southwest side of the subtropical high. This situation is beneficial to the western TCs obtaining water vapor from the southwest wind water vapor channel, and to the eastern TCs conveying water vapor to the western TCs, and then as a result, to the heavy rainfall over the Taiwan Island, the Southeast and the South Coasts of China caused by the western TCs.  相似文献   

15.
In this study, a ca. 4000 cal. yr ancient lacustrine (or wetland) sediment record at the southern margin of Tarim Basin is used to reconstruct the history of climate change. Six radiocarbon dates on organic matter were obtained. δ18O and δ13C of carbonate, pollen and sediment particle size were analysed for climate proxies. The proxies indicate that a drier climate prevailed in the area before ca. 1010 BC and during period 1010 BC–AD 500 climate then changed rapidly and continuously from dry to moist, but after about AD 500 climate generally shows dry condition. Several centennial‐scale climatic events were revealed, with the wettest spell during AD 450–550, and a relatively wetter interval between AD 930–1030. Pollen results show that regional climate may influence human agricultural activities. Spectral analysis of mean grain size (MGS) proxy reveals statistically pronounced cyclic signals, such as ca. 200 yr, ca. 120 yr, ca. 90 yr, ca. 45 yr and ca. 33 or 30 yr, which may be associated with solar activities, implying that solar variability plays an important role in the decadal‐ and centennial‐scale climate variations in the study area. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
利用1970 —2001 年1 ~12 月中国西北区冰雹日数的气象实测资料,将年冰雹日数发生的变化趋势看作每年的一个气候现象,分析其发生的气候变化趋势、年代际变化以及与大气环流的相关关系,得出多雹年北半球500 h Pa 极涡强、位置偏东,副热带高压面积小、强度弱、位置偏南,乌拉尔山至巴尔喀什湖高度场为正距平,雅库次克至贝加尔湖高度场为负距平。少雹年北半球500 h Pa 极涡弱、位置偏西,副热带高压面积大、强度强、位置偏北,乌拉尔山至巴尔喀什湖高度场为负距平,雅库次克至贝加尔湖高度场为正距平区。从而找出冰雹气候趋势预测的着眼点,建立冰雹短期气候预测概念模型;此模型对冰雹发生变化趋势的预测具有一定的实用价值。  相似文献   

17.
The social impact of global climate change is one of the hotspots in the current research. To deal with the challenges from climate change, it could be learned from the adapting experiences and lessons to climate change in the history. The main achievements of cognition on the historical impacts of climatic change in China and on coping with the climate changes in the future based the published papers in recent years is summarized. The followings are the main conclusions. ①The general characteristics of the impacts of climatic change in the history was negative in the cold periods and positive in the warm periods, but there were regional differences in the impact and responses. ②The cooling trend on centurial scale and the social economic decline run concurrently. The rapid development supported by better resources and environment in the warm period could lead to the increase of the social vulnerability when the climate turned to the cold period. ③Strategies and policies to cope with the climate change in the history were adopted according to the temporal and spatial circumstances and the subjects. Initiative adaptation promoted by governments was an effective way.  相似文献   

18.
In the source regions of the Yangtze and Yellow Rivers of China, glaciers, frozen ground, the hydrological system, and alpine vegetation have changed over the past decades years. Climatic causes of these variations have been analyzed using mean monthly air temperature and monthly precipitation between 1956 and 2000, and monthly evaporation from φ20 evaporation pans between 1961 and 1996. In the source region of the Yangtze River, lower temperature and plentiful precipitation during the 1960s and continuing into the early 1980s triggered a glacier advance that culminated in the early 1990s, while a robust temperature increase and precipitation decrease since 1986 has forced glaciers to retreat rapidly since 1995. Permafrost degradation is another consequence of the climatic warming. The variations in the hydrological system and alpine vegetation are controlled mainly by the climate during the warm season. Warmer and drier summer climate is the major cause of a degradation of the vegetation, desiccation of the high-cold marshland, a decrease in the areas and numbers of lakes and rivers in the middle and north source regions of the Yangtze and Yellow Rivers, and a reduction in surface runoff in the source region of the Yangtze River for the last 20 years. The causes of eco-environmental change in Dari area, near the outlet from the source area of the Yellow River, are different from those elsewhere in the study area. A noticeable reduction in runoff in the source region of the Yellow River and degradation of alpine vegetation in Dari area are closely related to the permafrost degradation resulting from climate warming.  相似文献   

19.
中国不同气候带盐风化作用的地貌特征   总被引:2,自引:0,他引:2  
盐风化作用是地球表面普遍存在的一种物理风化作用,由于盐类的周期性结晶作用而造成地表岩石和建筑材料的破坏,形成诸如风化穴或蜂窝石构造等地貌景观。盐风化作用也是差异风化的主要表现形式之一。然而,到目前为止盐风化作用在中国地学界仍然被严重忽视,以至于盐风化作用造成的地貌景观常常被地学研究者和科普人士误读为海浪冲蚀、流水侵蚀、风蚀作用等。经过近十年的野外观察与探讨,笔者等对盐风化的形成机理和表现形式有了深入的理解。本文以中国境内东部海岸带、华北半干旱区、西北干旱区和东南湿热气候带基岩露头为例,系统地分析了盐风化作用的机理及其在不同气候带的表现形式。盐风化的必要条件是:适当的可溶性盐类(如Na_2SO_4、NaCl等)供应、周期性的干湿交替和温度变化。盐风化作用主要在发育可渗性孔隙的砂砾岩类和富含微裂隙的花岗岩类之露头表面表现明显,可以形成特征显著的盐风化穴。盐风化作用形成的地貌景观在东部海岸带和西北干旱区表现尤为明显,常常形成蜂窝石构造和大型风化穴,与风蚀作用的痕迹明显有别;而在华北半干旱区和南方湿热气候带虽然受到降雨等其他因素的影响而常常遭受改造、叠加甚或清除,但在某些露头区仍然保留有重要的识别标志,形成大型风化穴以及小型蜂窝石构造。笔者等强调:地表各种地貌景观形成过程中都有盐风化作用的贡献,而建筑物和景观保护也必须考虑到盐风化作用的影响。建议地学同仁重视盐风化作用的普遍性和重要性,在相关教材中补充更新盐风化的概念,并以科普的方式通过多种媒体纠正过去的错误认识。  相似文献   

20.
江汉盆地始新世中、晚期气候变化周期性的孢粉学证据   总被引:6,自引:0,他引:6  
采用时间序列分析方法对江汉盆地明钾1孔的孢粉数据进行了处理,发现在中、晚始新世时期孢粉植物群的波动存在各种周期成分.长周期有1.2 Ma、2.0 Ma 及5.0 Ma,中周期有0.2 Ma、0.4 Ma、0.6 Ma、0.8 Ma,其中1.2 Ma及0.2 Ma、0.4 Ma、0.6 Ma的周期成分在第四纪孢粉植物群的演化中也存在,且与8.0 Ma B.P.以来的构造气候旋回,亚旋回的准1.2?Ma及0.4?Ma周期相一致.这表明地球运动轨道变化对气候的制约作用由来已久.该孔孢粉时间序列的趋势成分显示最少有4个水平,反映了孢粉植物群演化的4个阶段.曲线还揭示36 Ma B.P.前后的波动周期及振幅都有明显的变异,可能预示了一次大的环境变革.这一变化在很大程度上与喜马拉雅一期运动和地球南半球一次大的海洋和气候变冷事件相吻合.  相似文献   

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