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1.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):271-272
Dendrochronological crossdating was used to expand a pre-existing multi-millennial tree-ring chronology for Finnish Lapland. Twelve tree-ring series from sedimentary archives of five small lakes contributed to the oldest part of the chronology, extending the record to 5634 BC (previously 5520 BC). Today, the chronology is the longest conifer tree-ring chronology in Eurasia. The geologically oldest pine megafossils were found the eastern part of the region, i.e. north-east Finnish Lapland, and this is also where the authors expect that other very old pine megafossils may be found in the future. Cool climatic conditions c.8 ka ago may have prevented pine regeneration in the tundra-forest ecotone. This may explain the practical difficulty of making the chronology longer than its present form in the study region. 相似文献
2.
利用阿勒泰地区3个高海拔西伯利亚落叶松(Larix sibirica)采样点的树轮样本,建立树轮宽度区域标准化年表(DKH)。通过相关普查发现,DKH年表与阿勒泰地区7个气象站当年6月平均温度显著相关,相关系数为0.705(P<0.00001),表明6月平均温度是影响树木年轮径向生长的主要气候限制因子。用DKH年表可较好地重建该地区1572-2014年共443 a的初夏平均温度,解释方差达49.6%,经验证表明温度重建序列是可信的。温度变化特征分析表明:重建初夏温度经历了10个偏暖和9个偏冷阶段,其中1605-1622年和1682-1723年分别是最暖和最冷的阶段,1875-1913年和1753-1804年分别是持续时间最长的偏暖和偏冷阶段。存在2.37~2.39 a、2.19 a的显著周期(P<0.05)和73.50 a、14.00 a、7.30 a、2.29 a、2.21 a的较显著周期(P<0.10)。在1684年、1719年前后均出现了由冷转暖的突变。空间相关分析表明文章重建的温度序列对阿勒泰地区温度具有较好的空间代表性。本研究重建的初夏温度序列与阿勒泰西部5-9月平均温度和阿尔泰山南坡温度序列相比较,具有较好的一致性。 相似文献
3.
对新疆阿尔泰山中段森林上树线西伯利亚落叶松（Larix sibirica）树轮宽度标准化年表与区域气候要素进行相关分析,发现6月平均气温与树木径向生长存在显著相关关系（r=0.658,P<0.001）。据此重建的该地区1579-2009年间初夏温度变化曲线（解释方差为43.2%）表明,在过去431年,该地区经历了8个偏冷阶段和8个偏暖阶段,且对整个阿尔泰山有较好的空间代表性。功率谱分析表明,重建温度序列存在2.3a、2.4a的显著周期和3.9a、71.5a、95.3a的较显著周期。 相似文献
4.
Having analyzed the tree ring width and maximum latewood density of Pinus den-sata from west Sichuan, we obtained different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded princi-pally to the precipitation in current May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected summer temperature (June–September). According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of re-construction is 51% (F=52.099, p<0.0001). In the reconstruction series: before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, this trend was in accor-dance with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead of time, indicating that the Tibetan Plateau was more sensitive to temperature change. There was an evident sum-mer warming signal after 1983. Although the last 100-year running average of summer tem-perature in the 1990s was the maximum, the running average of the early 1990s was below the average line and it was cold summer, but summer drought occurred in the late 1990s. 相似文献
5.
基于采自柴达木盆地内部牦牛山的祁连圆柏树木样芯,新建采样区域过去2710 a的树轮宽度年表,并计算了器测时期（1957—2017 AD）气象数据与树轮宽度年表的相关系数。结果表明：树轮宽度年表与上一年7月至当年6月降水量变化的相关性最高（r=0.753,n=60,p <0.01）,基于此重建了该区392 BC—2017 AD上一年7月至当年6月的降水量变化。器测时期方差解释量高达64%。重建结果显示,在年代际尺度上存在9个湿润期（106—75 BC、6—39 AD、179—229 AD、581—646 AD、823—914 AD、1026—1095 AD、1378—1414 AD、1567—1609 AD和1985—2017 AD）和7个干旱期（328 BC—297 BC、86—151 AD、694—747 AD、1168—1199AD、1444—1525 AD、1680—1725 AD和1792—1860 AD）,1792—1860 AD是过去2400 a最干旱时期。功率谱分析结果表明,过去2400 a柴达木盆地东北部地区降水量存在2～8 a、40 a、80 a和225 a准周... 相似文献
6.
用树木年轮重建阿勒泰东部6-7月平均温度序列 总被引：1，自引：0，他引：1
利用采自阿勒泰中东部地区8个树轮采样点的西伯利亚落叶松树轮资料,建立宽度年表。分析这些年表与气候要素的相关性发现,标准化年表序列与该地区青河气象站6—7月的月平均气温存在显著的正相关关系,最高单相关为卓勒萨依ZLS年表,相关系数为0.555（P＜0.0001）,且具有明显的树木生理学意义。用卓勒萨依t和卓勒萨依t+3两个树轮标准化年表序列,可较好地重建该地区过去394 a来6—7月月平均气温序列,交叉检验表明,重建方程稳定可靠。分析发现,阿勒泰东部地区394 a来的气温重建序列具有7个偏冷和7个偏暖阶段,和2.7~3.7 a,43.7 a,52.4 a的显著冷暖变化准周期。月平均气温重建序列存在10个突变点,其中在1669年,1714年,1762年,1802年和1939年前后为初夏月平均气温由低向高突变,而在1691年,1732年,1781年,1919年和1963年前后是自高温向低温突变。 相似文献
7.
Having analyzed the tree ring width and maximum latewood density of Pinus den-sata from west Sichuan, we obtained different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded princi-pally to the precipitation in current May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected summer temperature (June-September). According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of re-construction is 51% (F=-52.099, p<0.0001). In the reconstruction series: before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, this trend was in accor-dance with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead of time, indicating that the Tibetan Plateau was more sensitive to temperature change. There was an evident sum-mer warming signal after 1983. Although the last 100-year running average of summer tem-perature in the 1990s was the maximum, the running average of the early 1990s was below the average line and it was cold summer, but summer drought occurred in the late 1990s. 相似文献
8.
Having analyzed the tree ring width and maximum latewood density of Pinus densata from west Sichuan, we obtained different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded princi- pally to the precipitation in current May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected summer temperature （June-September）. According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of reconstruction is 51% （F=52.099, p〈0.0001）. In the reconstruction series： before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, this trend was in accordance with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead of time, indicating that the Tibetan Plateau was more sensitive to temperature change. There was an evident summer warming signal after 1983. Although the last 100-year running average of summer temperature in the 1990s was the maximum, the running average of the early 1990s was below the average line and it was cold summer, but summer drought occurred in the late 1990s. 相似文献
9.
采用高山松最大密度重建川西高原近百年夏季气温 总被引：22，自引：1，他引：22
川西高原高山松树轮宽度及最大密度分析结果表明,最大密度年表和宽度年表中可提取的气候信息是不同的,在温暖、水分条件适中的地区,采用树木密度指标分析气候要素的变化是有效的途径。树轮宽度主要受5月降水影响,和西南季风活动有关;而最大密度主要指示了夏季(6￣9月)温度。利用转换函数重建了川西高原近百年来夏季(6￣9月)温度,重建序列的方差解释量为51%,(F=52.099,p<0.0001)。重建序列显示川西高原,30年代之前为偏冷期,30年代到60年代为偏暖期,与四川地区近百年的冷暖时期比较一致。与平原地区的成都相比,高原的升温转折点提前3年,表明高原地区对气温变化的响应更为敏感,川西高原地区可能是四川省气候变化的先兆地区。1983年以后川西高原地区夏季温度呈明显的上升趋势,20世纪90年代夏季温度的滑动平均为近百年的最大值,但在90年代初期仍处于均值线以下,表现为凉夏;90年代后半期表现为夏旱。 相似文献
10.
中国中世纪暖期气候研究综述 总被引：16，自引：8，他引：8
中世纪暖期是2000年来全球最重要的气候事件之一,关于中世纪暖期的研究,主要是通过各种代用资料重建气候序列。从目前的研究来看,能敏感响应环境变化的高分辨率的信息载体主要有冰芯、树轮、历史文献、湖泊沉积及石笋等。随着代用资料的开发,对于中世纪暖期的研究已经取得了丰硕的成果,但在中世纪暖期是否具有全球性,不同区域的起讫时间、增温幅度、内部波动以及成因机制等问题上还存在一定争议。主要原因是受重建资料敏感性与地域性限制,加上不同代用指标对气候变化敏感性的差异以及不同代用资料的方法、气候与环境意义等存在差异,定年存在误差。在中国,从对重建资料的整理分析来看,对于"中国是否存在中世纪暖期"这个问题,各研究者们没有达成一致的看法;对于中国中世纪暖期冷暖变化的研究,由于区域差异,东部重建资料以历史文献为主,而西部关于历史气候环境的相关记载很少,所以重建资料以冰芯、湖芯、树轮等为主。大多数的研究结果认为,西部的冷暖变化与东部有着明显的差异,其中最主要的是东部在900~1300 A. D.存在明显的温暖期,而西部则暖期不如东部明显。今后为了更加全面深入的了解中世纪暖期气候特征,应加强各种代用指标高分辨率序列的积累和定量化研究、各种代用指标和重建序列的综合集成研究及其与古气候模拟结果的比较研究,以期从动力学角度加深理解中世纪暖期的区域响应差异。 相似文献
11.
Juliane Wischnewski Ulrike Herzschuh Kathleen M. Rühland Achim Bräuning Steffen Mischke John P. Smol Lily Wang 《Journal of Paleolimnology》2014,51(2):287-302
The Tibetan Plateau is a region that is highly sensitive to recent global warming, but the complexity and heterogeneity of its mountainous landscape can result in variable responses. In addition, the scarcity and brevity of regional instrumental and palaeoecological records still hamper our understanding of past and present patterns of environmental change. To investigate how the remote, high-alpine environments of the Nianbaoyeze Mountains, eastern Tibetan Plateau, are affected by climate change and human activity over the last ~600 years, we compared regional tree-ring studies with pollen and diatom remains archived in the dated sediments of Dongerwuka Lake (33.22°N, 101.12°E, 4,307 m a.s.l.). In agreement with previous studies from the eastern Tibetan Plateau, a strong coherence between our two juniper-based tree-ring chronologies from the Nianbaoyeze and the Anemaqin Mountains was observed, with pronounced cyclical variations in summer temperature reconstructions. A positive directional trend to warmer summer temperatures in the most recent decades, was, however, not observed in the tree-ring record. Likewise, our pollen and diatom spectra showed minimal change over the investigated time period. Although modest, the most notable change in the diatom relative abundances was a subtle decrease in the dominant planktonic Cyclotella ocellata and a concurrent increase in small, benthic fragilarioid taxa in the ~1820s, suggesting higher ecosystem variability. The pollen record subtly indicates three periods of increased cattle grazing activity (~1400–1480 AD, ~1630–1760 AD, after 1850 AD), but shows generally no significant vegetation changes during past ~600 years. The minimal changes observed in the tree-ring, diatom and pollen records are consistent with the presence of localised cooling centres that are evident in instrumental and tree-ring data within the southeastern and eastern Tibetan Plateau. Given the minor changes in regional temperature records, our complacent palaeoecological profiles suggest that climatically induced ecological thresholds have not yet been crossed in the Nianbaoyeze Mountains region. 相似文献
12.
Jessica D. Tomkins Scott F. Lamoureux Dermot Antoniades Warwick F. Vincent 《Journal of Paleolimnology》2009,41(1):225-242
Sediment aggregates (“sedimentary pellets”) within the sedimentary record of Lake A (83°00′ N, 75°30′ W), Ellesmere Island,
Canada, are used to construct a 1000 year proxy record of ice-cover extent and dynamics on this perennially ice-covered, High
Arctic lake. These pellets are interpreted to form during fall or early winter when littoral sediment adheres to ice forming
around the lake’s periphery or during summer through the development of anchor ice. The sediment likely collects in ice interstices
and is concentrated in the upper ice layers through summer surface ice melt and winter basal ice growth. The pellets remain
frozen in the ice until a summer or series of summers with reduced ice cover allows for their deposition across the lake basin.
Sedimentary pellet frequency within multiple sediment cores is used to develop a chronology of ice-cover fluctuations. This
proxy ice-cover record is largely corroborated by a record of unusual sedimentation in Lake A involving iron-rich, dark-orange
to red laminae overlying more diffuse laminae with a lighter hue. This sediment sequence is hypothesized to represent years
with reduced ice cover through increased chemocline ventilation and iron deposition. During the past millennium, the most
notable period of inferred reduced ice cover is ca. 1891 AD to present. Another period of ice cover mobility is suggested
ca. 1582–1774 AD, while persistent ice cover is inferred during the 1800s and prior to 1582 AD. The proxy ice-cover record
corresponds well with most regional melt-season proxy temperature and paleoecological records, especially during the 1800s
and 1900s.
相似文献
| Jessica D. TomkinsEmail: |
13.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):303-311
A tree-ring chronology derived from Norwegian timber structures made from Scots pine at locations near Trondheim dates back to AD 552. A chronology based on Norway spruce building timber from the same area has been constructed back to AD 1351. Both Trondheim chronologies, when tested for climatic signals, show a year-to-year pattern that correlates with the annual variation in the May–August tetratherm from Trondheim dating back to 1870. Particular years in both these chronologies show correspondence with historical notes about the summer weather and harvests from 1575 until the mid-19th century. Especially cold summers resulted in unripe harvests and narrow tree-rings in both chronologies. However, several exceptions suggest that the growth of conifers and harvests sometimes responded differently to the same environmental factors (or more than one factor was important). The spruce chronology does not show reported long-term (decadal, century) climatic trends, probably because many samples had too few tree-rings. The pine chronology also shows little correspondence with longer-term fluctuations, probably because of heterogeneous material and/or too few samples. However, generally narrow ring widths from 1570 to the early 18th century may reflect a cold period. The data are promising, but results suggest that more samples and possibly more powerful statistics are required to extract reliable climatic signals from building timber chronologies. 相似文献
14.
Michael G. Loso 《Journal of Paleolimnology》2009,41(1):117-128
For the heavily glaciated mountains of southern Alaska, few high-resolution, millennial-scale proxy temperature reconstructions
are available for comparison with modern temperatures or with the history of glacier fluctuations. Recent catastrophic drainage
of glacier-dammed Iceberg Lake, on the northern margin of the Bagley Icefield, exposed subaerial outcrops of varved lacustrine
sediments that span the period 442–1998 AD. Here, an updated chronology of varve thickness measurements is used to quantitatively
reconstruct melt-season temperature anomalies. From 1958 to 1998, varve thickness has a positive and marginally significant
correlation with May–June temperatures at the nearest coastal measurement stations. Varve sensitivity to temperature has changed
over time, however, in response to lake level changes in 1957 and earlier. I compensate for this by log-transforming the varve
thickness chronology, and also by using a 400-year-long tree-ring-based temperature proxy to reconstruct melt-season temperatures
at Iceberg Lake. Regression against this longer proxy record is statistically weak, but spans the full range of occupied lake
levels and varve sensitivities. Reconstructed temperature anomalies have broad confidence intervals, but nominally span 1.1°C
over the last 1500+ years. Maximum temperatures occurred in the late twentieth century, with a minimum in the late sixth century.
The Little Ice Age is present as three cool periods between 1350 and 1850 AD with maximum cooling around 1650 AD. A Medieval
Warm Period is evident from 1000 to 1100 AD, but the temperature reconstruction suggests it was less warm than recent decades—an
observation supported by independent geological evidence of recent glacier retreat that is unprecedented over the period of
record.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
| Michael G. LosoEmail: |
15.
Melissa L. Chipman Gina H. Clarke Benjamin F. Clegg Irene Gregory-Eaves Feng Sheng Hu 《Journal of Paleolimnology》2009,41(1):57-75
We analyzed sediments of the past 2000 years from Ongoke Lake, southwest Alaska, for organic carbon, organic nitrogen, biogenic
silica (BSi), and diatom assemblages at decadal to centennial resolution to infer limnological changes that may be related
to climatic variation in southwestern Alaska. The chronology is based on a 210Pb profile from bulk sediments and nine AMS 14C ages from terrestrial plant macrofossils. Four of the 14C ages span a core depth interval of 60.5 cm but are statistically indistinguishable from one another with a mean of ~1300
AD, which compromises the determination of temporal trends at Ongoke Lake and comparison with other paleoclimate records.
The diatom record suggests changes in the duration of ice cover and strength of thermal stratification that are probably related
to temperature variation. This variation includes a cold interval around the first millennium cooling (FMC) and a warm interval
spanning the medieval climate anomaly (MCA). However, the lake-sediment record shows no clear signals of temperature variation
for the period of the Little Ice Age (LIA) or the twentieth century. Climatic changes during these periods may have been manifested
through effective-moisture (precipitation minus evapotranspiration) variation in the Ongoke Lake area. We estimate water depths
and infer effective-moisture fluctuations by applying a regional transfer function to our diatom record. Together with inferences
from diatom autecologies, this water-depth reconstruction suggests that effective moisture increased steadily from 50 BC to
350 AD, which was followed by relatively dry conditions between 550 and 750 AD and relatively wet conditions between 750 and
1450 AD. Effective moisture was low from ~1450 to 1850 AD, coinciding with the LIA; an alternative age model places this interval
between ~1315 and 1850 AD. During the past 150 years, effective moisture increased, with estimated water depths reaching peak
values in the second half of the twentieth century. This study offers the first paleolimnological record for inferring centennial-scale
climatic variation over the past two millennia from southwestern Alaska.
相似文献
| Feng Sheng HuEmail: |
16.
祁连山中部树木年轮宽度与气候因子的响应关系及气候重建 总被引：33，自引：13，他引：20
研究了祁连山中部不同海拔高度青海云杉的树轮宽度对气候因子的响应,重建了祁连山中部 230 a以来春季3~5月的降水和 170 a以来夏季6~8月的气温序列。结果分析发现,不同高度的云杉树轮生长对春季降水极为敏感,呈现显著正相关;对夏季气温的响应程度,各海拔高度却不相同,夏季气温对上、下限云杉生长有显著影响,但对于森林中部云杉作用并不明显,总体表现为负相关,夏季高温对树木生长不利。气候重建结果发现,祁连山中部的春季230 a以来经历了大幅度长阶段的干湿变化,存在明显的 69 a和 21a周期;170 a以来夏季气温变化频繁,存在明显的2~4a周期。目前,祁连山中部正处于相对干旱和温暖时期,呈现出向暖干方向发展的趋势。 相似文献
17.
新疆哈密八大石森林上限树轮记录的温度变化信息 总被引：1，自引：0，他引：1
本研究采集新疆哈密地区八大石西伯利亚落叶松森林上限树芯样本,建立标准宽度年表.通过树木年轮-气候响应分析,发现标准年表序列反映了该地生长季(5～9月)的月平均温度及月平均最低温度信息,且该序列与前人的研究结果对比具有较好的一致性.树轮宽度序列主要反映出了1885年之前以冷期为主,1885年之后以暖期为主,且暖期延续时间变长,20世纪后半期增温的趋势.该序列与天山冰川进退的时间较为一致,同时也发现该序列极值与当地蝗灾具有很好的对应,与亚洲近两百年来的大型火山喷发事件具有很好的一致性,由此可以推测该年表在一定程度上捕捉到了冰川进退、火山事件的环境信息. 相似文献
18.
Pollen-based reconstructions of late Holocene climate from the central and western Canadian Arctic 总被引：1，自引：0，他引：1
Two lake-sediment cores from the western and central Canadian Arctic were used to investigate late Holocene climate variability
in the region. Both cores were analyzed for pollen, organic matter, biogenic silica, and magnetic susceptibility, and were
dated using a combination of 210Pb and 14C techniques. Core MB01, from southwestern Victoria Island, provides a 2600-year-long record. Fossil pollen percentages, along
with other parameters, suggest the occurrence of a cold period around 2400 cal year BP (450 BC), followed by slightly warmer
conditions by 1800 cal year BP (150 AD), and a return to cooler conditions throughout much of the last millennium. Core SL06,
from southern Boothia Peninsula, shows more subtle changes in pollen percentages over its 2500-year duration, but an increase
in Cyperaceae and decrease in Oxyria pollen around 1400 cal year BP (550 AD) are indicative of warmer conditions at that time. Quantitative climate reconstructions
from these pollen sequences were compared to two other pollen-based climate records from the region and indicate the presence
of a widespread wet period ~1500 cal year BP (450 AD), and a cool and dry Little Ice Age. In the reconstructions based on
pollen percentage data, the twentieth century summer temperature and annual precipitation in the central and western Canadian
Arctic were comparable to that which occurred over the last 2500 years. However, pollen-influx values increase in the most
recent sediments, suggesting high plant productivity during the late twentieth century.
相似文献
| Matthew C. PerosEmail: |
19.
The Sudetes Mountains (Central Europe) were under a particularly intense long-term air pollution load during the 1970s and 1980s. Intense industrial activity in this area led to large-scale forest dieback and reductions in tree growth rates, potentially limiting the use of tree-ring data from this region in dendroclimatic research. In this paper, ring-width chronologies were constructed for 493 Norway spruce trees (Picea abies L. Karst.) from 17 sampling sites within five major mountain ranges in the Sudetes Mountains of Poland. Growth-climate response data indicate that April?July temperatures are the main factor affecting radial growth of trees in the study area. Our data also indicate the strong influence of slope aspect on temperature signal strength. The lowest correlation values were obtained for sites located on western slopes with effective fog deposition, which are strongly affected by pollution. An appropriate sampling strategy resulted in the creation of a temperature-sensitive proxy record (rAMJJ = 0.70), exceptional for areas under strong pressure from human activity. Based on a regional master chronology, growing season (April?July) temperatures over the past 200 years were then reconstructed. Four warm and four cold periods were distinguished and compared with other reconstructions and long-term instrumental data. 相似文献
20.
新疆伊犁地区近250年冷暖变化特征分析 总被引：13，自引：1，他引：13
用树木年轮年表可重建过去的气候，扩展对气候变化的全面估计，本文利用伊犁地区２２个树轮年表，重建了该地区２５０年平均温度序列，并对周期冷暖变化特征进行了分析，对未来趋作了预测。 相似文献