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| 1 | Abrupt Holocene changes of the Asian monsoon at millen-nial-and centennial-scales: Evidence from lake sediment document in Minqin Basin, NW China显示文摘Considerable research is now focusing on abrupt Holocene changes at millennial- and centennial-scales all over the world. This study shows that the changes in theHolocene summer monsoon can be divided into two main periods, based on climatic proxy records of lake sediments from the Sanjiaocheng section located at the NW boundary of the summer monsoon, Gansu Province. The early and middle Holocene was humid with stronger summer monsoon, while the late Holocene is dry with weak summer monsoon. Detailed results also show a series of millennial- and centennial-scale changes in the intensity of the summer monsoon, with a periodicity of 1600 years during the whole Holocene, and with a periodicity of 800 years during the early Holocene. Ten dry events during the Holocene are associated with the weakening of the summer monsoon. These rapid climatic changes may be representative of a global climatic change pattern during the Holocene. | CHEN Fahu ZHU Yan LI Jijun SHI Qi JIN Liya B.Wunemann | 2001 | Chinese Science Bulletin2001，46，23： | 61 |
| 2 | Spatiotemporal precipitation variations in the arid Central Asia in the context of global warming显示文摘This study analyzed the temporal precipitation variations in the arid Central Asia (ACA) and their regional differences during 1930-2009 using monthly gridded precipitation from the Climatic Research Unit (CRU). Our results showed that the annual precipitation in this westerly circulation dominated arid region is generally increasing during the past 80 years, with an apparent increasing trend (0.7 mm/10 a) in winter. The precipitation variations in ACA also differ regionally, which can be divided into five distinct subregions (I West Kazakhstan region, II East Kazakhstan region, III Central Asia Plains region, IV Kyrgyzstan region, and V Iran Plateau region). The annual precipitation falls fairly even on all seasons in the two northern subregions (regions I and II, approximately north of 45°N), whereas the annual precipitation is falling mainly on winter and spring (accounting for up to 80% of the annual total precipitation) in the three southern subregions. The annual precipitation is increasing on all subregions except the southwestern ACA (subregion V) during the past 80 years. A significant increase in precipitation appeared in subregions I and III. The long-term trends in annual precipitation in all subregions are determined mainly by trends in winter precipitation. Additionally, the precipitation in ACA has significant interannual variations. The 2-3-year cycle is identified in all subregions, while the 5-6-year cycle is also found in the three southern subregions. Besides the inter-annual variations, there were 3-4 episodic precipitation variations in all subregions, with the latest episodic change that started in the midto late 1970s. The precipitations in most of the study regions are fast increasing since the late 1970s. Overall, the responses of ACA precipitation to global warming are complicated. The variations of westerly circulation are likely the major factors that influence the precipitation variations in the study region. | CHEN FaHu HUANG Wei JIN LiYa CHEN JianHui WANG JinSong | 2011 | Science China Earth Sciences2011，54，12： | 64 |
| 3 | Tree ring based streamflow reconstruction for the Upper Yellow River over the past 1234 years显示文摘We established a Juniperus przewalski tree ring width chronology, based on tree ring cores collected from the A’nyêmaqên Mountains. Statistical analysis showed that the chronology was highly correlated with instrumental streamflow records from previous August to current July from the Tangnaihai Station in the upper reaches of the Yellow River, with a correlation coefficient of 0.656. Streamflow for the upper reaches of the Yellow River was reconstructed for the past 1234 years. Low flow periods for the 11-year averaged streamflow reconstruction were definite as lower than mean plus 1 standard deviation, and high flow periods were higher than mean minus 1 standard deviation. Over the past 1234 years, high flows occurred 18 times, and low flows occurred 12 times. The main low flow periods were identified as AD 1140–1156, AD 1295–1309, AD 1473–1500, and AD 1820–1847, and the main high flow periods were identified as AD 846–873, and AD 1375–1400. Extremely low streamflow over the reconstruction period was seen during the late 15th century, coinciding with a widespread drought phenomenon, which took place in the northeastern Tibetan Plateau over the same period. Reconstructed streamflow shows significant low-frequency variability, which is in line with drought variability of neighboring regions, as inferred from tree rings and other proxies. Multi-taper spectral analysis suggests the existence of significant periods of 2–5, 22, 35–38, 55–62, and 114–227 years, particularly significant for cyclic variations of years 159 and 36. | GOU XiaoHua DENG Yang CHEN FaHu YANG MeiXue FANG KeYan GAO LinLin YANG Tao ZHANG Fen | 2010 | Chinese Science Bulletin2010，55，36： | 37 |
| 4 | Exploring the history of cultural exchange in prehistoric Eurasia from the perspectives of crop diffusion and consumption显示文摘The history of cultural exchange in prehistoric Eurasia(CEPE) has been widely investigated. Based on archaeological evidence, this process is thought to date back to at least the early Bronze Age, although details about timings and routes remain unclear. It is likely that CEPE promoted the spread and exchange of crops that originated in different parts of Eurasia; since these remains can be definitely identified and directly dated, they provide ideal research materials to explore the history of CEPE. In this paper, we review the available archaeobotanical evidence and direct radiocarbon dates for crop remains, alongside carbon isotopic data from human bones unearthed from prehistoric sites in Eurasia, in order to investigate the history of the spread of millet crops, and wheat and barley, that were first domesticated in the eastern and western parts of Eurasia during prehistoric times.In combination with other archaeological evidences, we discuss the history of CEPE. Our results suggest that wheat and barley were domesticated in western Asia around 10500 a BP, spread into Europe and western Central Asia before 8000 a BP, and reaching eastern Central Asia and northwestern China between 4500 and 4000 a BP. Data show that both broomcorn and foxtail millet were domesticated in eastern Asia before 7700 a BP, spread into eastern Central Asia between 4500 and 4000 a BP, and into western Asia and Europe prior to 3500 a BP. Wheat, barley, and millet crops were first utilized together in eastern Kazakhstan within Central Asia around 4400 a BP, the region where earliest CEPE is likely to have taken place. These crops were mixedly used mainly in eastern central Asia and northwest China between 4500 and 3500 a BP, and then across the Eurasia before 2200 a BP. The results of this study suggest that transcontinental CEPE might have been initiated during the fifth millennium, before intensifying during the Bronze Age to lay the foundations for the creation of the ancient Silk Road during the Han Dynasty(between 202 BC and 220AD). | DONG GuangHui YANG YiShi HAN JianYe WANG Hui CHEN FaHu | 2017 | Science China Earth Sciences2017，60，6： | 30 |
| 5 | Estimation of China’s terrestrial ecosystem carbon sink:Methods,progress and prospects显示文摘China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060,during the General Assembly of the United Nations in September 2020.In this context,the potential of the carbon sink in China’s terrestrial ecosystems to mitigate anthropogenic carbon emissions has attracted unprecedented attention from scientific communities,policy makers and the public.Here,we reviewed the assessments on China’s terrestrial ecosystem carbon sink,with focus on the principles,frameworks and methods of terrestrial ecosystem carbon sink estimates,as well as the recent progress and existing problems.Looking forward,we identified critical issues for improving the accuracy and precision of China’s terrestrial ecosystem carbon sink,in order to serve the more realistic policy making in pathways to achieve carbon neutrality for China. | Shilong PIAO Yue HE Xuhui WANG Fahu CHEN | 2022 | Science China Earth Sciences2022，65，4： | 30 |
| 6 | Humid Medieval Warm Period recorded by magnetic characteristics of sediments from Gonghai Lake, Shanxi, North China显示文摘Variations in monsoon strength, moisture or precipitation in eastern China during the MWP reflected by different climatic records have shown apparent discrepancies. Here, detailed environmental magnetic investigations and mineralogical analyses were conducted on lacustrine sediments of Core GH09B1 (2.8 m long) from Gonghai Lake, Shanxi, North China, concerning the monsoon history during the MWP. The results demonstrate that the main magnetic mineral is magnetite. The sediments with relatively high magnetic mineral concentrations were characterized by relatively fine magnetic grain sizes, which were formed in a period of relatively strong pedogenesis and high precipitation. In contrast, the sediments with low magnetic mineral concentrations reflected an opposite process. The variations of magnetic parameters in Gonghai Lake sediments were mainly controlled by the degree of pedogenesis in the lake drainage basin, which further indicated the strength of the Asian summer monsoon. The variations in the and S 300 parameters of the core clearly reveal the Asian summer monsoon history over the last 1200 years in the study area, suggesting generally abundant precipitation and a strong summer monsoon during the Medieval Warm Period (MWP, AD 910–1220), which is supported by pollen evidence. Furthermore, this 3–6-year resolution environmental magnetic record indicates a dry event around AD 980–1050, interrupting the generally humid MWP. The summer monsoon evolution over the last millennium recorded by magnetic parameters in sediments from Gonghai Lake correlates well with historical documentation (North China) and speleothem oxygen isotopes (Wanxiang Cave), as well as precipitation modeling results (extratropical East Asia), which all indicate a generally humid MWP within which centennial-scale moisture variability existed. It is thus demonstrated that environmental magnetic parameters could be used as an effective proxy for monsoon climate variations in high-resolution lacustrine sediments. | LIU JianBao CHEN FaHu CHEN JianHui XIA DunSheng XU QingHai WANG ZongLi LI YueCong | 2011 | Chinese Science Bulletin2011，56，23： | 28 |
| 7 | Variations of organic carbon isotopic composition and its environmental significance during the last glacial on western Chinese Loess Plateau显示文摘A high-resolution loess section in the western Chinese Loess Plateau, Yuanbao Section, was sampled for organic carbon isotopic analyses. The soil organic carbon isotope (δ13Corg) varied be- tween ?22.6‰ and ?27.5‰ during the last glacial at the section. During the last interstadial, the δ 13Corg values were more negative than those in both early and late periods of the last glacial by 4‰. The iso- topic composition indicates a coupled response of the pure C3 plants to the temperature, precipitation and the concentration of atmospheric CO2. Decrease in temperature and the atmospheric CO2 concentration from the last interstadial to Last Glaicial Maximum (LGM) caused the organic carbon isotopes to be- come positive by 1.5‰―2.0‰. The amplitude of 4‰ in the δ 13Corg variation during the last glacial should be mainly caused by the precipitation change. Therefore, the δ 13Corg variations of the Yuanbao Section during the last glacial period documented the large-amplitude fluctuation of the monsoon precipita- tion, which is estimated to be 250―310 mm more during the last interstadial than that in the LGM, and 100 mm more than that during early last glacial. The rapid changes of the monsoon precipitation on mil-lennial scale during the last glacial have also been recorded in the isotopic variations in Yuanbao loess section. As the isotopic composition varies compli- catedly as shown in the loess-paleosol sequence, it cannot be simply attributed to the abundances of C3 and C4 plants or be used as an indicator of the summer monsoon variations. | CHEN Fahu RAO Zhiguo ZHANG Jiawu JIN Ming MA Jianying | 2006 | Chinese Science Bulletin2006，51，13： | 25 |
| 8 | Definition of the core zone of the “westerlies-dominated climatic regime”, and its controlling factors during the instrumental period显示文摘The term 'westerlies-dominated climatic regime' describes the pattern of precipitation/moisture variations between westerliesdominated arid Central Asia(ACA) and mid-latitude monsoon-dominated Asia on decadal to multi-millennial time scales. However, no attempts have been made to define its core region and the possible physical mechanisms responsible during the period of instrumental observations. The present study investigates the spatiotemporal variations of summer and winter precipitation on interannual to decadal time scales over mid-latitudes of the Eurasian continent using Empirical Orthogonal Function(EOF) analysis. Our results suggest the existence of an opposing pattern of summer precipitation variations between ACA and mid-latitude monsoon-dominated Asia and Mediterranean on decadal time scales. Based on these results, the core region influenced by the westerlies is outlined, including arid central Asia and Xinjiang in China(36°–54°N, 50°–90°E). By using monthly NCEP-NCAR reanalysis, the relationship between the 'westerlies-dominated climatic regime' and atmospheric circulation were also analyzed. The combination of the zonal climatic teleconnection pattern and anomalous Indian Summer Monsoon Precipitation(ISMP) causes the precipitation characteristics of the 'westerlies-dominated climatic regime' precipitation pattern. In addition, the Atlantic Multidecadal Oscillation(AMO) may also have an important effect on the 'westerlies-dominated climatic regime'. | HUANG Wei CHEN JianHui ZHANG XiaoJian FENG Song CHEN FaHu | 2015 | Science China Earth Sciences2015，58，5： | 24 |
| 9 | Preliminary research on Megalake Jilantai-Hetao in the arid areas of China during the Late Quaternary显示文摘我们识别了 geomorphological,在通过地调查并且通过地区性的遥感的分析的当前的 Jilantai 盐湖附近的高湖层次的沉积、生物的证据想象。在约 1060, 1050, 1044 和 1035 m a.s.l 的举起有四组海岸线,是在当前的盐湖上面的 37, 27, 21 和 12 m 分别地出现。沙和石子的沿岸的存款在在 1070 和 1080 m a.s.l 之间的举起被发现,比水流高的 47 ~ 57 m 腌湖表面,尽管 palaeoshoreline 地形仅仅在几个地点被保存。在 Herimuxini,在 Ulan Buh 荒芜的、典型湖的沉积和沙石子的北边缘上,沿岸的存款也发生在 1080 m a.s.l 并且在下面的举起。典型吐痰扩大的 A 11-km-long 从逐渐地在它的大拐弯上沿着黄河的南部的银行在一些沙石子石场从 1050 ~ 1035 m a.s.l 在举起减少的这条海岸线东方海岸线特征例如在水文学计量器车站和 Shilazhao 镇附近定位的那些,被识别。沿岸的存款 overlying 冲积的洪水的层在 Hangjin 在 Balagong 附近发生在沙石场县。也有沙滩岩石和沿岸的存款,沿着 Langshan-Yinshan 山的南部的山麓在几个地点在 cut-and-built 平台上保存。另外,揭示水下的三角洲沉积的侧面在 Wuhai 附近被识别,在黄河进入盆的地方。典型的湖沉积也在 Hetao 平原的东方结束在 Togtoh 站台存在。水的软体动物壳在沿岸的存款是普通的,包括 Corbicula 的几种,根值 lagotis, R。xauricularia 和 Gyraulus convexiusculus。Ostracode 壳能也在更好的沉积被识别。典型垂直 prograding 序列在湖的沉积很好被保存的露头是明显的。滚动波浪的卵石和沙滩岩石很通常在更高的举起在堤在侧面的顶上被保存。所有这些证据建议曾经有一个巨大的palaeo湖,用到达我们指的 ∼1080 m a.s.l 的最高的湖水平盖住 Jilantai 区域和 Hetao 平原的大多数部分巨大的 paleolake ,比现代的湖贝加尔湖大,作为“ Megalake Jilantai-Hetao ”. OSL 标明日期结果显示大湖以前形成了 ∼60 —50 ka,和在在 1060 和 1035 m a.s.l 之间的举起的四条海岸线多半从 ∼60 ∼50 ka 代表湖水平变化到早 Holocene。Megalake Jilantai-Hetao 的发现将多半影响黄河的发展的理解在期间晚第四级, Ulan Buh 和 Kubq 的进化抛弃,在这个区域的 neotectonism,并且可能地区性的气候的变化。 | CHEN FaHu FAN YuXin CHUN Xi D.B. MADSEN C.G. OVIATT ZHAO Hui YANG LiPing SUN Yang | 2008 | Chinese Science Bulletin2008，53，11： | 23 |
| 10 | Interannual precipitation variations in the mid-latitude Asia and their association with large-scale atmospheric circulation显示文摘This study analyzed the spatial differences of the precipitation variations in the mid-latitude Asia and their possible physical mechanisms during 1960–2009.The annual precipitation showed an opposite variations between the westerlies-dominated arid Central Asia(ACA)and monsoon-dominated North China(NC)during the study period.Given the different contributions of seasonal precipitation to annual total precipitation in ACA and NC,the atmospheric circulation anomalies during the major precipitation seasons(winter in ACA/summer in NC)were analyzed.In winter,negative North Atlantic Oscillation may cause negative height anomalies over the north side and positive anomalies over the south side of the ACA.Together,the enhanced pressure gradient and anomalous westerly wind brings more water vapor to ACA,and leaves less precipitation in NC.In summer,the low-pressure anomalies in Northeast China,along with a weaker summer monsoon and negative height anomalies in Eastern Europe together contribute to reduced(excessive)summer precipitation in NC(ACA).The interactions between ENSO and NAO may result in the opposite precipitation variations between ACA and NC.A significant 2–3-year cycle is identified in ACA,which is linked to the variations of westerly circulation in the middle troposphere. | HUANG Wei CHEN FaHu FENG Song CHEN JianHui ZHANG XiaoJian | 2013 | Chinese Science Bulletin2013，58，32： | 21 |
| 11 | Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years显示文摘An oxygen isotope record of a stalagmite from Huanglong Cave in the eastern Qinghai-Tibet Plateau dated with 230Th and 210Pb methods provides variations of the Asian monsoon with an average resolu-tion of 1 year over the past 50 years. This study shows that the δ18O of dripwater in the cave represents the annual mean δ18O of local meteoric precipitation and the stalagmites were deposited in isotopic equilibrium. A comparison of the stalagmite δ18O record with instrumentally meteorological data indi-cates that shifts of the δ18O are largely controlled by the amount effect of meteoric precipitation con-veyed through the southwest monsoon(the Indian monsoon) and less affected by temperature. Therefore,the variations of δ18O record reflect the changes in monsoon precipitation on inter-annual time scales under the influence of the southwest monsoon. Like many other stalagmite δ18O records in the Asian monsoon regions,the δ18O record of the stalagmite from Huanglong Cave also reveals a gradually enriched trend during the past 50 years,i.e. relatively enriched in 18O. This trend may indicate the decline of the Asian monsoon intensity which is consistent with the decrease of monsoon indices. The weakening of the modern Asian monsoon well matched with the temperature changes in strato-sphere,which may illustrate that the weakening of the monsoon mainly results from the lowering of solar radiation. | YANG XunLin ZHANG PingZhong CHEN FaHu HUH Chih-an LI HongChun CHENG Hai Kathleen R. JOHNSON LIU JingHua AN ChunLei | 2007 | Chinese Science Bulletin2007，52，9： | 20 |
| 12 | A 1000-year chironomid-based salinity reconstruction from varved sediments of Sugan Lake,Qaidam Basin,arid Northwest China,and its palaeoclimatic significance显示文摘A 1000-year high-resolution(~10 years) chironomid record from varved sediments of Sugan Lake,Qaidam Basin on the northern Tibetan Plateau,is presented.The chironomid assemblages are mainly composed of the relatively high-saline-water taxa Psectrocladius barbimanus-type and Orthocladius/Cricotopus,and the relatively low-saline-water taxa Procladius and Psectrocladius sordidellus-type.Variations in the chironomid fauna and inferred salinities suggest that over the last millennium,the Sugan Lake catchment has alternated between contrasting climatic conditions,having a dry climate during the period 990―1550 AD,a relatively humid climate during the Little Ice Age(LIA)(1550―1840 AD),and a dry climate again from 1840 AD onwards.At the decadal to centennial scale,a wet event around 1200―1230 AD,interrupting the generally arid period(990―1550 AD),and a dry event around 1590―1700 AD,punctuating the generally humid period(1550―1840 AD),are clearly documented.Trends in the chironomid-based salinity time series indicate a highly unstable climate during the LIA when salinity fluctuations were of greater magnitude and higher frequency.The effective moisture evolution in the Sugan Lake catchment during the last millennium reconstructed by chironomid analysis is in broad agreement with previous palaeo-moisture data derived from other sites in arid Northwest China(ANC).The LIA,characterized by generally humid conditions over the west-erly-dominated ANC was distinctly different from that in monsoonal China,implying an 'out-of-phase' relationship between moisture evolution in these two regions during the past 1000 years. | CHEN JianHui CHEN FaHu ZHANG EnLou BROOKS Stephen J ZHOU AiFeng ZHANG JiaWu | 2009 | Chinese Science Bulletin2009，54，20： | 20 |
| 13 | Pollen-inferred vegetation and environmental changes since 16.7 ka BP at Balikun Lake, Xinjiang显示文摘A high-resolution fossil pollen record from the sedimentary cores of Balikun Lake, northwestern China, combined with modern surface pollen data, is used to reconstruct the history of vegetation and climatic change since 16.7 cal. ka BP. Fossil pollen assem-blages and lithology indicate that the study area was dominated by desert. The desert had extremely arid climate and lower effec-tive moisture during 16.7–7.9 cal. ka BP, especially from 16.7 to 8.9 cal. ka BP when the lake maybe dried up. During 8.9–7.9 cal. ka BP, the environment gradually recovered in this area. It was then followed by the optimum period from 7.9 to 4.3 cal. Ka BP, when the effective moisture obviously increased. It was characterized by the typical desert-steppe/steppe vegetation and was ac-companied with several patch-birch woodlands around the lake. After that, a short but extremely arid climatic event occurred during 4.3–3.8 cal. ka BP, and the vegetation quickly changed from desert-steppe/steppe to desert. It was a relatively optimum period from 3.8 to 0.53 cal. ka BP showing typical desert-steppe/meadow-steppe landscape. Since 0.53 cal. ka BP, the climate has shown signs of deteriorating again. Furthermore, regional comparison shows that the characteristics of climatic and environmental evolution in this area were clearly different from East Asia monsoonal area during the last 16.7 cal. ka BP. It was characterized by the arid climate during the late-glacial and early Holocene, and relatively wet during the mid-late Holocene. | TAO ShiChen AN ChenBang CHEN FaHu TANG LingYu WANG ZongLi LU YanBin LI ZhiFei ZHENG TongMing ZHAO JiaJu | 2010 | Chinese Science Bulletin2010，55，22： | 20 |
| 14 | Palaeovegetational and palaeoenvironmental changes since the last deglacial in Gonghe Basin, northeast Tibetan Plateau显示文摘在在向东北西藏的高原的 monsoonal 边缘的 Paleoenvironmental 历史提供重要线索给地区性的气候。以前的研究被差的年表或低分辨率限制了。这里我们在场从从 Dalianhai 拿的一个 40.92-m-long 沉积核心( DLH )的一个高分辨率的花粉记录,位于 Gonghe 盆的一个终端湖,自从最后 deglacial ,植被和气候历史由 10 AMS 14C 根据一张年表控制了的为重建的向东北西藏的高原在在核心沉积保存的植物遗体上标明日期。在 DLH 核心的花粉集合能被划分成 6 个花粉地区和每个地区被树或植物花粉百分比的生长和衰落主要描绘。在 14.812.9 ka 和 9.43.9 ka 的时期期间,亚高山带的树木、本地的草本的花粉增加了,显示亚高山带的森林在大草原或典型大草原在在相对更潮湿的气候下面的 Gonghe 盆开发了的包围山脉和沙漠发展了。在 15.814.8 ka, 12.99.4 ka 和 3.91.4 ka 的时期期间,森林根据干旱,和荒芜的大草原的不同的度缩小了或消失在盆降级了到更多的干旱大草原沙漠,显示干燥气候。在 1.4 ka 以后,在 Dalianhai 附近的植被类型被增加的 Artemisia 建议的大草原主要统治。我们的结果建议了在这个区域的历史是的气候从 15.814.8 ka 干燥、从 14.812.9 ka 潮湿、从 12.99.4 ka,气候在 9.43.9 ka 期间在以后是潮湿的干燥,在最后 1.4 ka 在 3.91.4 ka 和潮湿的条件期间由干燥条件列在后面。自从最后 deglacial,花粉百分比和在 Dalianhai 的 palaeovegetation 的进化的变化类似于在金海·莱克记录的那些。森林在 B 期间在 Dalianhai 附近在山膨胀了 ?lling 都 ? d 时期,在更年轻的 Dryas 和早 Holocene 期间缩小了,然后,它在 mid-Holocene 开发了并且到达它的最大值。在迟了的 Holocene 期间,植被开始缩小了到消失为止。然而,在 Holocene 预定森林扩大落后于金海·莱克的,并且这空间异质被在这二个地方之间的不同森林种类可能引起。在 mid-Holocene 的森林开发的最大值与在石笋记录显示的早 Holocene 的更强壮的夏天季风的时期不一致,原因可能与对一个大规模气候的变化的植被反应的复杂性有关。 | CHENG Bo CHEN Fahu ZHANG Jiawu | 2013 | Journal of Geographical Sciences2013，23，1： | 20 |
| 15 | Climatic changes documented by stable isotopes of sedimentary carbonate in Lake Sugan,northeastern Tibetan Plateau of China,since 2 kaBP显示文摘Lake Sugan at the northern edge of the Qaidam Basin was selected as the research object. The temporal se-quence of sedimentary cores retrieved from Lake Sugan since 2 kaBP was reconstructed using the 210Pb, AMS 14C and conventional 14C dating methods. Carbon and oxygen iso-topes of carbonate in the fine-grained lake sediments were analysed. Combined with the changes of δ 18O values of sur-face water and air temperature observation data in the study area, it might be thought that the δ 18O value of the carbon-ate indicates effective moisture, and the changes in δ 13C val-ues are related to annual freeze-up duration of the lake and indirectly indicate air temperature changes in winter half year. From the above, the sequence of climatic changes in the region since 2 kaBP was established. The climatic changes experienced five stages: Warm-dry climate during 0-190 AD; cold-dry climate during 190-580 AD; warm-dry cli-mate during 580-1200 AD (MWP); cold-wet climate during 1200-1880 AD (LIA); cold-dry climate during 1880-1950 AD; and climate warming since 1950s. The air temperature changes in winter half year reflected by carbon isotope since 2 kaBP are in good agreement with the historical literature records and other geologic records, which shows that the climate changes recorded by the stable isotopes from Lake Sugan since 2 kaBP are of universal significance. | QIANG Mingrui CHEN Fahu ZHANG Jiawu GAO Shang-yu ZHOU Aifeng | 2005 | Chinese Science Bulletin2005，50，17： | 19 |
| 16 | On the timing of the East Asian summer monsoon maximum during the Holocene Does the speleothem oxygen isotope record reflect monsoon rainfall variability?显示文摘The evolution of the East Asian summer monsoon(EASM) during the Holocene has long been of significant interest.Knowledge of past EASM variability not only increases our understanding of monsoon dynamics on a long timescale,but it also provides an environmental and climatic background for research into Chinese cultural development.However,the timing of the EASM maximum remains controversial.The popular concept of an 'early Holocene maximum' is mainly based on speleothemδ^(18)O(δ^(18)O_c) records from caves in southern China;however,the interpretation of δ^(18)O_C as a reliable proxy for EASM intensity is being increasingly challenged.The present paper is a critical review of the climatic significance of the δ^(18)O_C record from China.Firstly,we suggest that precipitation in northern China is an appropriate index of EASM intensity,the variation of which clearly indicates a mid-Holocene monsoon maximum.Secondly,an interregional comparison demonstrates that the precipitation record in northern China is quite different from that in southern China on a range of timescales,and is inconsistent with the spatial similarity exhibited by speleothem oxygen isotope records.Furthermore,both modeling and observational data show that the δ^(18)O_C records from southern China indeed reflect changes in precipitation δ^(18)O(δ^(18)O_P) rather than precipitation amount,and therefore that their use as an EASM proxy is inappropriate.Finally,we address several significant monsoon-related issues-including the driving mechanism of the EASM on an orbital timescale,the climatic significance of speleothem oxygen isotopes,and the relationship between atmospheric circulation and precipitation in monsoonal regions. | CHEN JianHui RAO ZhiGuo LIU JianBao HUANG Wei FENG Song DONG GuangHui HU Yu XU QingHai CHEN FaHu | 2016 | Science China(Information Sciences)2016，59，12： | 18 |
| 17 | The discovery of annually laminated sediments (varves) from shallow Sugan Lake in inland arid China and their paleoclimatic significance显示文摘Detailed examination of sedimentary cores retrieved from Sugan Lake in the northern Qaidam Basin of northwest China’s Tibetan Plateau reveal that fine laminated beddings form in the sediments where water depth exceeds 3 m. Seasonal surface sediments trapped at the bottom of the lake suggest that sediments deposited during summer and autumn are mainly light colored monohydrocalcites, while those deposited in winter are dark organic matter, indicating that varve layers form under modern limnological conditions. Continuous varve sediments comprising four types have accumulated in the upper 5.5 m of Core SG03I from the center of the lake. All types exhibit clear seasonality indicative of annual deposition. Varve counts correspondence with 210Pb dates on recent sediments in the upper core suggest the continuous varves of the upper 5.5 m of the core formed in the late Holocene (2670 a BP). The Sugan Lake varve sequence is the first demonstration of annually laminated sediments re-ported in arid western China. | ZHOU AiFeng CHEN FaHu QIANG MingRui YANG MeiLin ZHANG JiaWu | 2007 | Science China Earth Sciences2007，50，8： | 17 |
| 18 | A 457-year reconstruction of precipitation in the southeastern Qinghai-Tibet Plateau,China using tree-ring records显示文摘This paper presents a 457-year reconstruction of precipitation in the southeastern Qinghai-Tibet Plateau using tree-ring records.Tree-ring samples were collected from the Hengduan Mountains in the southeastern part of the Qinghai-Tibet Plateau,China.A nearly 500-year chronology was developed using tree-ring width records.Correlation analysis shows moisture is the main factor limiting tree growth in this region.Ring-widths were significantly positively correlated with the Palmer Drought Severity Index(PDSI) and precipitation in many months.The highest correlation coefficient was found between the annual growth of trees and precipitation from the previous September to the current June(0.738).Based on this relationship,we reconstructed the precipitation history from 1509 to 2006.The reconstruction explains 54.4%(Radj2=53.5%,N=49,F=56.12) of the actual precipitation variation during the calibration period(1958-2006).During the reliable period of the reconstruction(1549-2006),some low-frequency climate signals are included,indicating this region has been getting wetter in the last 20 years.The reconstruction documents six apparently dry and five pluvial periods and the 17th century dry period lasted longer than any other.When compared with other recent studies,this study and these earlier reconstructions show a similar trend in the variation of drought and pluvial.Further spatial correlation analysis confirms that the reconstructed precipitation adequately represents the rainfall history of the entire Hengduan Mountain area.The Multi-taper method,a type of spectral analysis,reveals that precipitation in this area had significant(P<0.01) spectral peaks at 3-5 a,60 a and 79-85 a. | GOU XiaoHua YANG Tao GAO LinLin DENG Yang YANG MeiXue CHEN FaHu | 2013 | Chinese Science Bulletin2013，58，10： | 16 |
| 19 | Sedimentary documents and Optically Stimulated Luminescence (OSL) dating for formation of the present landform of the northern Ulan Buh Desert,northern China显示文摘GPR reflecting sections and core profiles revealed that sand dunes of the northern Ulan Buh Desert are overlying shallow lacustrine or palustrine sediments. Optical dating results of sediments from three core profiles indicate that the area of the northern Ulan Buh Desert was still covered by the shallow lake or marsh during 8.4-6.4 ka, and eolian sand started to accumulate since around 2 ka. Such a result supports the idea that the present desert landform of the northern Ulan Buh Desert started to form since 2 ka, which was likely a response to the desertification caused by ruin of the Han Dynasty and the large-scale abandonment of farming of the Han nationality. Our research results are consistent with the previous archaeological studies, and support the idea that the Ulan Buh Desert is composed of two parts with different histories, i.e., the old southern Ulan Buh Desert and the young northern Ulan Buh Desert. | Fan YuXin Chen FaHu Fan TianLai Zhao Hui Yang LiPing | 2010 | Science China Earth Sciences2010，53，11： | 15 |
| 20 | A climatological northern boundary index for the East Asian summer monsoon and its interannual variability显示文摘A long-term perspective on the spatial variation of the northern boundary of the East Asian summer monsoon(EASM) and the related physical mechanisms is important for understanding past climate change in Asia and for predicting future changes. However, most of the meteorological definitions of the EASM northern boundary do not correspond well to the actual geographical environment, which is problematic for paleoclimatic research. Here, we use monthly CMAP and GPCP precipitation data to define a new EASM northern boundary index by using the concept of the global monsoon, which is readily applicable to paleoclimatic research. The results show that the distribution of the 2 mm day^(-1) precipitation isoline(i.e., 300 mm precipitation)has a good relationship with the spatial distribution of modern land cover types, the transitional climate zone and the potential natural vegetation types, in China. The locations of the precipitation isolines also correspond well to the locations of major shifts in wind direction. These results suggest that the 2 mm day^(-1) isoline has a clear physical significance since the climatic, ecological,and geographical boundary can be used as the northern boundary index of the EASM(which we call the climatological northern boundary index). The index depicts the northeast-southwest orientation of the climatological(1981-2010) EASM northern boundary, along the eastern part of the Qilian Mountains-southern foothills of the Helan Mountains-Daqing Mountains-western margin of the Greater Khingan Range, from west to east across Northwest and Northeast China. The interannual change of the EASM northern boundary from 1980 to 2015 covers the central part of Gansu, the northern part of Ningxia, the eastern part of Inner Mongolia and the northeastern region in China. It can extend northward to the border between China and Mongolia and retreat southward to Shangdong-central Henan. There is a 200-700 km fluctuation range of the interannual EASM northern boundaries around the locations of the climatological northern boundary. In addition, the spatial variation of the interannual EASM northern boundaries gradually increases from west to east, whereas the trend of north-south fluctuations maintains a roughly consistent location in different regions. | CHEN Jie HUANG Wei JIN LiYa CHEN JianHui CHEN ShengQian CHEN FaHu | 2018 | Science China Earth Sciences2018，61，1： | 14 |
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