Late Holocene annual growth in three Alpine stalagmites records the influence of solar activity and the North Atlantic Oscillation on winter climate

Annual growth rates and the ratio of dark to light-colored calcite within single annual laminae in three contemporaneously deposited Holocene speleothems from Grotta di Ernesto, an Alpine cave in northern Italy, respond to changes in surface temperature rather than precipitation. Based on monitoring of present-day calcite growth, and correlation with instrumental data for surface climatic conditions, we interpret a higher ratio of dark to light-colored calcite and the simultaneous thinning of annual laminae as indicative of colder-than-present winters. Such dark and thin laminae occur in those parts of the three stalagmites deposited from AD 1650 to 1713 and from AD 1798 to 1840, as reconstructed through lamina counting. These periods correspond to the well-known Maunder and Dalton Minima of solar activity. An 11-yr cyclicity in growth rate, coupled with reduced calcite deposition during the historic minima of solar activity, is indicative of a solar influence on lamina thickness. Spectral analysis of the lamina thickness data also suggests that the North Atlantic Oscillation variability influenced winter temperatures. Based on the present-day controls on cave calcite formation, we infer that high-frequency changes in solar activity modulated the seasonal duration of soil CO₂ production.     

利用洞穴石笋的δ18O和δ13C重建3000a以来北京地区古气候和古环境——石花洞研究系列之三

首次提出用石笋中稳定同位素记录重建由降雨量和降水气团同位素组成所反映的古气候历史，从而为研究高分辨率的古季风气候信息开辟了新的途径。利用Ｈｅｎｄｙ准则、洞穴温度、研究区水系的δ１８ＯＨ２Ｏ值以及温度公式，证实了同位素分析结果的可靠性，ＣａＣＯ３－Ｈ２Ｏ之间存在同位素平衡分馏。对采自石花洞的石笋样品进行了分辨率约为２５ａ的δ１８Ｏ和δ１３Ｃ的分析测量，从而得到３０００ａ以来，北京地区古气候和古环境的变化信息     

Temporal and spatial variations in the discharge and dissolved organic carbon of drip waters in Beijing Shihua Cave,China

To detect the causal relationship between cave drip waters and stalagmite laminae, which have been used as a climate change proxy, three drip sites in Beijing Shihua Cave were monitored for discharge and dissolved organic carbon (DOC). Drip discharges and DOC were determined at 0 to 14‐day intervals over the period 2004–2006. Drip discharges show two types of response to surface precipitation variations: (1) a rapid response; and (2) a time‐lagged response. Intra‐annual variability in drip discharge is significantly higher than inter‐annual variability. The content of DOC in all drip waters varies inter‐ and intra‐annually and has good correlation with drip water discharge at the rapid response sites. High DOC was observed in July and August in the three years observed. The flushing of soil organic matter is dependent upon the intensity of rain events. The DOC content of drip water increases sharply above a threshold rainfall intensity (>50 mm d^?1) and shows several pulses corresponding with intense rain events (>25 mm d^?1). The DOC content was lower and less variable during the dry period than during the rainy period. The shape of DOC peak also varies from year to year as it is influenced by the intensity and frequency of rainfall. The different drip sites show marked differences in DOC response, which are dominated by hydrological behaviour linked to the recharge of the soil and karst micro‐fissure/porosity network. The results explain why not all stalagmite laminae are consistent with climate changes and suggest that the structure of the rainy season events could be preserved in speleothems. Copyright © 2008 John Wiley & Sons, Ltd.     

Correlation between high-resolution climate records from a Nanjing stalagmite and GRIP ice core during the last glaciation

A 400-mm-long stalagmite from Tangshan Cave, Nanjing has been analyzed by a high-precision TIMS-U series dating method and also determined for oxygen and carbon stable isotopic compositions. The results provided a high-resolution paleoclimate record for eastern China during a time interval (from 54 000 to 19 000 aBP) of the last glaciation. The continuous record of oxygen-18 variations in the stalagmite, indicating a precipitation history of the East Asian monsoon, shows not only signals of the Heinrich events, but also the Dansgaard-Oeschger cycles which are first found in the last glacial climate record of the East Asian monsoon area. Although the stalagmite-based climatic signals match well with the GRIP ice core record, some differences between the two records can be recognized: (1) The last glacial climate changes in eastern China exhibited a long-term remarkably cooling trend, superimposed on which were four successive Bond’s cycles illustrated by the δ¹⁸O curve. This strong cooling tendency may be an effect of the strong summer monsoon event during the MIS 3 over the Tibetan Plateau. (2) There exist some phase differences of 1000–2000 years between the cooling events in the stalagmite-based climate signal and the GRIP ice core record. Such differences should be further verified by calibrations of multiple dating methods     

Accurate chronological construction for two young stalagmites from the tropical South Pacific

Modern to Holocene tropical Pacific stalagmites are commonly difficult to date with the U-series, the most commonly used dating method for speleothems. When U-series does not provide robust age models, due to multiple sources of ²³⁰Th or little U, radiocarbon is, potentially, the best alternative. The ¹⁴C content of two stalagmites (Pu17 and Nu16) collected from Pouatea and Nurau caves in the Cook Island Archipelago of the South Pacific were measured to obtain accurate chronology for their most modern parts. The bomb-pulse soil continuum modelling indicates that bomb radiocarbon in Pu17 onsets in 1956 and reaches its maximum in 1966 CE, suggesting a fast transfer of atmospheric carbon to the stalagmite of <1 year. The modelling for Pu17 suggests a 20% contribution from C₁ - an instantaneous carbon source, which renders possible an immediate transfer of atmospheric signal into the cave. Nu16 shows a slower transfer of atmospheric carbon to the stalagmite than Pu17, with bomb radiocarbon onsetting in 1957 CE and peaking in 1972 CE. The less negative δ¹³C values in Nu16 than Pu17, and also the modelling corroborated this, which points out no contribution from the instantaneous carbon source. The radiocarbon age models and laminae counting age models were then spliced to achieve a single master chronology for the top part of each stalagmite. This study is an example of ¹⁴C age modelling combined with visible physical and chemical laminae counting and how it can improve the accuracy and precision of dating for otherwise hard-to-date tropical Pacific speleothems. Such accurate and precise age models pave the way to obtain sub-annually resolved paleoclimate records by further improving the calibration of climate proxy data with the current and instrumental weather parameters.     

A method to anchor floating chronologies in annually laminated speleothems with U–Th dates

Stalagmites occasionally present laminae which, when demonstrated to be annual, may be used to construct an annually resolved chronology. Such annually laminated records provide an opportunity to improve the precision of age models based on other dating techniques. Since annually laminated stalagmites sometimes present a complex stratigraphy with lateral variations in lamina thickness associated with changing macroscopic growth shapes, a procedure for lamina counting is developed here, which complements other methods of speleothem lamina counting. Regardless of the complexity of laminae, when the exact date of a laminated section is unknown, lamina counting provides a floating chronology. This paper describes a method to anchor floating chronologies in speleothems using the least-squares fit of the lamina counting to the radiometric dates (typically U–Th). The estimation of uncertainties in the age model is also considered, which accounts for uncertainties in the lamina counting as well as the fit of the lamina count to the radiometric dates. The uncertainty of this fit does not depend on the analytical uncertainty of the radiometric dates or the precision in the lamina counting, and simply considers all the available dates and their distance to the proposed age model. As an example, the method was applied to a stalagmite from Northern Spain and its accuracy was compared with the annually resolved and cross-dated Greenland chronology during the 8.2 ka event. Although this method has been described for stalagmites, it could be applied to other records in which cross-dating techniques would not be suitable.     

Very high-frequency and seasonal cave atmosphere PCO2 variability: Implications for stalagmite growth and oxygen isotope-based paleoclimate records

Cave air P_CO2 at two Irish sites varied dramatically on daily to seasonal timescales, potentially affecting the timing of calcite deposition and consequently climate proxy records derived from stalagmites collected at the same sites. Temperature-dependent biochemical processes in the soil control CO₂ production, resulting in high summer P_CO2 values and low winter values at both sites. Large Large-amplitude, high-frequency variations superimposed on this seasonal cycle reflect cave air circulation. Here we model stalagmite growth rates, which are controlled partly by CO₂ degassing rates from drip water, by considering both the seasonal and high-frequency cave air P_CO2 variations. Modeled hourly growth rates for stalagmite CC-Bil from Crag Cave in SW Ireland reach maxima in late December (0.063 μm h^− 1) and minima in late June/early July (0.033 μm h^− 1). For well-mixed ‘diffuse flow’ cave drips such as those that feed CC-Bil, high summer cave air P_CO2 depresses summer calcite deposition, while low winter P_CO2 promotes degassing and enhances deposition rates. In stalagmites fed by well-mixed drips lacking seasonal variations in δ¹⁸O, integrated annual stalagmite calcite δ¹⁸O is unaffected; however, seasonality in cave air P_CO2 may influence non-conservative geochemical climate proxies (e.g., δ¹³C, Sr/Ca). Stalagmites fed by ‘seasonal’ drips whose hydrochemical properties vary in response to seasonality may have higher growth rates in summer because soil air P_CO2 may increase relative to cave air P_CO2 due to higher soil temperatures. This in turn may bias stalagmite calcite δ¹⁸O records towards isotopically heavier summer drip water δ¹⁸O values, resulting in elevated calcite δ¹⁸O values compared to the ‘equilibrium’ values predicted by calcite–water isotope fractionation equations. Interpretations of stalagmite-based paleoclimate proxies should therefore consider the consequences of cave air P_CO2 variability and the resulting intra-annual variability in calcite deposition rates.     

Temperature variations recovered from tree-rings in the middle Qilian Mountain over the last millennium

During the past 1000 years, there had been sev-eral widespread climate events on the earth, such asthe ‘Medieval Warm Period’, the ‘Little Ice Age’ andthe recent warming from the later part of the nine-teenth century onward[1,2]. To better understand thedetails of climatic history on a regional scale, morehigh-resolution, millennia-length climate reconstruc-tions are needed by intensive, multiproxy investigationof ice cores, sediments of loess and lakes, corals andtree-rings. Since …     

A possible Younger Dryas-type event during Asian monsoonal Termination 3

1 Introduction The Younger Dryas (YD) cold spell is one of the most prominent abrupt climate change events in the past and a key feature of the last glacial termination. A great agreement has been attained in terms of the tim- ing and geographic extent of…     

The 1800-year variation of the lower Yellow River bank breachings in relation to the drainage basin vegetation reconstructed using cave stalagmite records

Rivers are closely related to climate, and the hydrogeomorphic features and stability of river channels respond sensitively to climatic change. However, the history of instrumental observations of climatic, hydrological and channel changes is short, notably limiting our ability to understand the complex river responses to long-term climate change and human activity. In this study, we show that cave stalagmite records reflected the variations in precipitation and temperature in the Yellow River basin, and the net primary productivity (NPP) of vegetation over the past 1800 years can therefore be reconstructed. We found that the reconstructed annual mean precipitation (P_m) and NPP closely related to the 1800-year variation of the lower Yellow River (LYR) channel instability indexed by the frequency of the LYR levee breaching events (LBEs) (F_b) derived from historical documents. The temporal variations in P_m, NPP and F_b exhibited an anti-phase relationship (negative correlation) and in-phase relationship (positive correlation), referred to as Type I and Type II relationships, respectively. The two types alternately appeared, dividing the studied period into several sub-periods. Type I occurred when the vegetation remained in a quasi-natural condition, and Type II occurred when the vegetation had been altered by humans to some degree. These features reflect complex river behaviours in response to climate change and human activity and may be explained by the interaction between climate, vegetation and human activity on the millennial timescale. © 2018 John Wiley & Sons, Ltd.     

Applications of interannual-resolution stable isotope records of speleothem: Climatic changes in Beijing and Tianjin, China during the past 500 years—the δ 18O record

δ¹⁸O of a stalagmite collected from Shihua Cave, 50 km southwest of Beijing is analyzed. The uppermost 2 cm was sampled at about 3-year intervals by a computer-controlled microsampling device. A total of 133 samples were analyzed, covering the last 480 years. A comparison of the δ¹⁸O record with the instrumentally recorded precipitation in Beijing and Tianjin back to 1840 AD shows that high precipitation correlates with negative δ¹⁸O peaks. The long-term δ¹⁸O trend records temperature changes. Between 1620 and 1900 AD, the temperature was cooler than the average value for the 480-year record, corresponding to the Little Ice Age. Temperatures warmer than the average prevailed during 1520–1620 and 1900—present. Superimposed on the long-term trend are about 14 δ¹⁸O cycles of 30–40-year periodicity, with wet periods centered around 1985, 1955, 1910, 1880, 1840, 1800, 1760, 1730, 1690, 1660, 1630, 1600, 1560 and 1530 AD. Project supported by the National Natural Science Foundation of China (Grant No. 9615875).     

A quick cooling event of the East Asian monsoon responding to Heinrich Event 1: Evidence from stalagmite δ18O records

Based on TIMS U-series dating results and annual band counting method, an annual-resolution time scale from 17450 to 14420 aBP has been established for a stalagmite from the Hulu Cave at Tangshan, Nanjing. A high-resolution oxygen isotopic record reveals decadral-centural oscillations in air temperature in the East Asian monsoon climate area during the last glacial maximum. The most conspicuous feature in the oxygen isotopic record in the period is the particular cold event synchronized with the last Heinrich event (H1) in the northern Atlantic deep-sea records. This particular cold event, beginning at 16140 ( 100 aBP, shows a rapid cooling down with a magnitude of 7-8℃ in air temperature within 36 years. Furthermore, (6)18O record demonstrates that the event lasted 790 years with gradually warming tendency (10 cycles of air temperature oscillations) after the remarkable cooling down. We believed that this unique pattern of event recorded in the stalagmite ? 8O might be controlled by various factors including changes of insolation at mid-latitude Northern Hemisphere, the southern extend of the last ice-rafted event in the North Atlantic and changes of the Equatorial Pacific sea surface temperature.     

High-resolution peat records for Holocene monsoon history in the eastern Tibetan Plateau

Holocene peat sediment has been attached impor-tance to reconstruct the Holocene climatic variations because it can provide much palaeoclimatic informa-tion with high resolution. Analysis on the plant mac-rofossil[1], pollen[2―4], isotope ratio[5―9], element con-tent[10,11], total organic carbon (TOC)[12], humifica-tion[13,14] and grayscale[12] for peat sediment has shown its superiorities as a recorder medium for reconstruct-ing the Holocene climate. Hong et al. have done great fruitful w…     

雁荡山湖泊沉积物记录的中国东部季风区小冰期以来气候干湿变化

中国东部季风区过去千年降水变化特征已有大量研究并取得重要进展,但多数研究集中在中国北方和中部地区,南方地区重建记录相对较少.本文对浙江雁荡山雁湖沉积物的总有机碳、色度和粒度等多指标进行分析,重点探讨小冰期以来研究区域的降水变化,结果显示:1)1400-1600 AD,湖区集水发育,研究区气候偏湿润;2)1600-1650 AD,降水量减少,气候偏干旱;3)1650-1750 AD,气候偏湿润;4)1750-2000 AD,研究区气候处于干旱状态,其中1500-1650 AD期间的干湿变化与历史文献记录的雁湖水位有良好的对应关系.在年代误差范围内,雁湖沉积物与浙江天目山泥炭、福建仙山泥炭以及湖光岩玛珥湖沉积物等记录的干湿变化同步,指示了小冰期期间中国东南地区气候波动的一致性.另外,中国东部南、北地区古气候记录反映的降水变化趋势相反,表明在百年时间尺度上,中国东部南北地区降水存在着"南涝北旱"和"北涝南旱"的空间特征.通过与太平洋年代际振荡(PDO)的对比,显示PDO对中国东部地区小冰期期间出现的南-北"偶极型"空间降水特征可能具有重要影响.     

A quick cooling event of the East Asian monsoon responding to Heinrich Event 1: Evidence from stalagmite δ<Superscript>18</Superscript>O records

Based on TIMS U-series dating results and annual band counting method, an annual-resolution time scale from 17450 to 14420 aBP has been established for a stalagmite from the Hulu Cave at Tangshan, Nanjing. A high-resolution oxygen isotopic record reveals decadral-centural oscillations in air temperature in the East Asian monsoon climate area during the last glacial maximum. The most conspicuous feature in the oxygen isotopic record in the period is the particular cold event synchronized with the last Heinrich event (H1) in the northern Atlantic deep-sea records. This particular cold event, beginning at 16140 ± 100 aBP, shows a rapid cooling down with a magnitude of 7–8°C in air temperature within 36 years. Furthermore, δ¹⁸O record demonstrates that the event lasted 790 years with gradually warming tendency (10 cycles of air temperature oscillations) after the remarkable cooling down. We believed that this unique pattern of event recorded in the stalagmite δ⁸O might be controlled by various factors including changes of insolation at mid-latitude Northern Hemisphere, the southern extend of the last ice-rafted event in the North Atlantic and changes of the Equatorial Pacific sea surface temperature.     

New progress in the Holocene climate and agriculture research in China

Global climate change and its possible ecological consequences have become the focused issue (IPCC, 2007; Mann et al., 2008; Ding et al., 2009). The Holocene contains the analogous characteristic of future climatic change and the continuous agriculture activity, providing the ideal “similar pattern” for studying the climate change and human adaption and impact in the future. Based on the recent studies of stalagmite, ice core, ocean, and lake etc., the paper introduces the new progress in the Holocene climate and agriculture research in China as follows: (1) Discuss the variability, amplitude, and unstable characteristic of climate, as well as the abrupt events and mechanisms of climate. (2) Analyze the botanical index records for studying the early agriculture. (3) Review the agricultural origin, expanding, and development. (4) Reveal the style and intensity of early agriculture and understand the agricultural impact and adaption to the environmental changes. (5) Introduce ongoing research projects in China and emphasize the significance of increasing the dating precision and the indicative effectiveness of proxies. (6) Realize how the ecosystem and environmental factors respond to the increasing temperature process, understand how the human adapt to the rapid climate change, and provide the scientific basis for assessing the effects of climate change and the human adaption in the future.     

淮河中游本世纪气候与环境波动的湖泊记录证据

为研究本世纪淮河中游气候与环境波支的湖泊沉积响应,１９９１年秋季在女山湖湖心提取了４．８ｍ沉积物。对顶部２０ｃｍ沉积物运用＾１２６Ｐｂ、＾１３７Ｃｓ的年代定位,获得１９０４－１９９１年湖泊沉积物的年序。以此通过高分辨沉积记录的代用标志提取,重建了本女山湖气候与环境的变化过程。结果表明,本世纪最初２０－３０年女山湖地区温度偏低、湿度偏大;４０、５０年代为本世纪温度最高的时段,５０至６０年代中期为延结     

近130ka中国黄土磁化率气候记录与南极冰芯气候记录

黄土高原中部的陕西泾阳、旬邑黄土剖面具有高分辨率气候记录,记录了130ka 以来的气候波动,一些细微的气候波动也被记录下来。位于大陆的黄土磁化率气候记录可以与南极冰芯气候记录对比。结果表明:Lorius 与 Jouzel 等将冰芯同位素曲线划分为 A、B、C、D、E、F、G、H 冷暖阶段,可与黄土磁化率气候曲线划分的1、2、3、4、（5、6、7）、8,9、10冷暖阶段对比。其中冰芯记录所反映的 A、C、E、G（或黄土记录反映的1、3、5、6、7、9）为暖阶段:B、D、F、H（2、4、8、10）为冷阶段。总之,黄土磁化率记录曲线与冰芯气候记录曲线的形态极为相似,指示了黄土高原地区的大陆气候变化与极地气候变化同受全球变化的影响。这证明了极地冰量变化与东亚大陆冬、夏季风强弱变化,是全球气候变化在极地与大陆的两种表现形式。黄土记录的气候变化时间滞后于冰芯记录,可能暗示着大陆气候变化滞后于极地气候变化。     

Circulation background of climate patterns in the past millennium: Uncertainty analysis and re-reconstruction of ENSO-like state

The question of whether or not global warming has paused since more than ten years ago, namely "warming hiatus", has attracted the attention of climate science community including the IPCC. Some authors have attributed the "warming hiatus" to the internal changes in the climate system, i.e., the recombination of ocean-atmosphere circulations. Therefore, it is necessary to propose higher requirements on reconstructing circulation background of climate change for the past millennium. However, the analyses of changes in atmospheric circulation over the last millennium as well as the conclusions of related regional climate patterns are so widely different and contradictory, bringing uncertainties to our understanding of regional even global climate change to a great extent. On the other hand, in the last 10 years the high-precision U/Th-dated stalagmite oxygen isotope ratio(δ~(18)O) sequences provided an accurate chronological frame for the paleoclimate study of the middle and late Pleistocene, in which all authors from China took the Chinese stalagmite δ~(18)O as the summer monsoon index without exception. However, this point of view misleads the climate scientists into thinking that the stalagmite δ~(18)O can be as the proxy of precipitation amount. Nevertheless, it is well known that all of these records have a lot in common in the low frequency trend. However, most sequences cannot be calibrated by instrumental precipitation records, and thus the uncertainty of the climate research framework of China and even of the world has increased. Therefore, it is imperative for climatology to clarify the origin of contradiction and to reduce the uncertainty as early as possible. On the basis of analyzing the significance of stalagmite δ~(18)O in the monsoon regions of China, the author tries to propose a new circulation proxy in this paper: integrating the Chinese stalagmite oxygen isotope sequence to reconstruct the tropical Pacific sea surface temperature gradient, i.e., the large-scale ENSO-like state over the past millennium. Furthermore, the author speculates that it was warm in the modern times and the Medieval Period, but the circulation recombination was different in both periods. And this inference could be supported by the longer record since Last Glacial Maximum. In other words, the attribution analysis of the identical low-frequency trends of Chinese stalagmite δ~(18)O on a large scale shows that the ENSO-like state controls the climate change in the monsoon regions of China at different time scales(from interannual to century or even longer time scales). Wherein the important connection of circulations is the western Pacific subtropical high(WPSH), that is to say, besides the interannual and decadal time scales, the WPSH would possess the circulation mode on longer timescales. For example, we may discuss the change of the WPSH in the whole Holocene epoch, i.e., the half precession period. These discussions could make sense to the study of not only the paleoclimate but also the modern climate.     

The Y. D. and climate abrupt events in the early and middle Holocene: Stalagmite oxygen isotope record from Maolan,Guizhou, China

Changes of climate, especially the abrupt changesof precipitation and temperature lead frequently tograve effect in human productive and living activity.Since the 1950s, results of monitoring indicate thatatmosphere CO2 concentration rises by 1.4×10?6g/gevery year. The atmospheric greenhouse effect leadsprobably to global warming since the 1940s, whichbrings furthermore special attention of scientists andrelevant government organizations in various coun-tries. In the near 20 years, the …