Comparison of precipitation variations at different time scales in the northern and southern Altai Mountains
ZHANG Dongliang
1
,
2
,
,
LAN Bo
1
,
2
,
YANG Yunpeng
1
,
2
1. Xinjiang Institute of Ecology and Geography, CAS, Urumqi 830011, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
As one of the most important regions for paleoclimate study, the Altai Mountains are influenced by the prevailing westerly airflow throughout a year. In order to get a better understanding of the precipitation variations at different time scales (i.e., season, year, multi-decades, centennial and millennial scales) in the northern and southern Altai Mountains, we investigate the observed data from 11 meteorological stations and published paleoclimate documents (including tree rings, ice cores and lake cores) in the northern and southern Altai Mountains. The results show that the precipitation during the observed interval experiences a decreasing trend in the northern Altai Mountains, whereas an increasing trend in the southern Altai Mountains. The out-of-phase relationship of precipitation in the northern and southern Altai Mountains also exists in the two centennial intervals, the last millennium and the Holocene epoch. We propose that the out-of-phase relationships of precipitation variations at different time-scales (i.e., season, year, multi-decades, centennial and millennial scales) indicate that the Altai Mountains are an important climatic boundary. However, the reasons of out-of-phase relationship at different time-scales remains to be investigated in the future. The next work is not only helpful to understand the history of regional water vapor change, but also contributes to the understanding of the succession of the Silk Road culture along the Europe-Asian steppe.
Keywords:
Altai Mountains
precipitation
different time scales
paleoclimate
张东良
,
兰波
,
杨运鹏
.
不同时间尺度的阿尔泰山北部和南部降水对比研究
[J].
, 2017, 72(9): 1569-1579
https://doi.org/10.11821/dlxb201709003
ZHANG
Dongliang
,
LAN
Bo
,
YANG
Yunpeng
.
Comparison of precipitation variations at different time scales in the northern and southern Altai Mountains
[J].
地理学报
, 2017, 72(9): 1569-1579
https://doi.org/10.11821/dlxb201709003
近20年来,有关阿尔泰山全新世(即过去11500年前)气候变化研究已取得了相当丰硕的成果
[
1
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。最近学者们对阿尔泰山北部和南部的古气候重建资料进行了综述,其中有两个综述较为突出。第一个是Ran等
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综述的阿尔泰山南部(新疆北部)全新世资料。结果揭示新疆北部在过去8000年前以前气候较为干旱,约8000年以来区域湿度逐渐增加。第二个是Wang等
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综述的阿尔泰山北部全新世资料。他们的结果揭示自全新世以来,阿尔泰山区域气候呈现逐渐变干的趋势。可见,阿尔泰山北部和南部全新世气候在千年尺度上呈现完全相反地变化。但是,这种相反的关系是否在其他时间尺度上(季节、年、十年、百年尺度)依然是存在的呢?本文将通过追踪阿尔泰山北部和南部已发表的不同时间段的气候记录(包括器测时段、过去200年时段和过去1000年时段),来讨论不同时间尺度上其北部和南部的降水(或水文)变化特征。
2 资料来源
本文所选用器测降水数据来自11个气象站(5个位于俄罗斯境内、2个位于蒙古境内、4个位于中国境内),分布位置如
图1
所示,相关信息如
表1
所示。其中俄罗斯境内的5个气象站分别是Kyzyl-Ozek、Yailu、Ust-Coksa、Kosh-Agach和Kara-Tyurek,数据来自俄罗斯水文气象信息研究所,观测时段是1966-2015年。蒙古境内的两个气象站是Ulgii和Hovd,数据来自Malyigina等
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13
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文章,没有获得原始资料,观测时段是1959-2015年。中国境内的气象站分别是青河、富蕴、阿勒泰和哈巴河,数据来自中国气象局气象数据中心(http://data.cma.cn/),观察时段为1954-2015年。在本文的分析中,这11个气象站均选择的是月降水数据。
Tab. 1
表1 阿尔泰山北部和南部气象站点的相关信息
Tab. 1 Information of meteorological stations in the northern and southern Altai Mountains
Fig. 3 Precipitation variations of the past 200 years in the northern Altai Mountains (a. Tree-ring isotope-based precipitation during June-August
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; b. Tree-ring width-based precipitation during August-June
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; c. Glacier accumulation in Belukha Ice Core
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Fig. 4 Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
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; b. Chen et al.
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; c. Xu et al.
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24
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; d. Zhang et al.
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;e. Hu et al.
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)
Dzhangyskol is a small lake of glacial origin in the central part of the Altai Mountains in southern Siberia. Pollen stratigraphies and chronologies of two cores record the vegetational development of the area from the Late Glacial treeless landscape to the forest and steppe of today. The modern lake is a remnant of a much larger ice-dammed lake, which was reduced in size and then temporarily drained after diversion of the inflowing mountain meltwater stream, which had low 18 O values. The dry lake floor allowed development of permafrost and small pingos (frozen mounds of lake sediments). With the onset of greater climatic humidity in the mid-Holocene, the input of local water with higher 18 O caused a rise in lake level, drowning the earlier pingos. Growth of a broad fen on the margin of the lake led to formation of a modern pingo complex.
Three well-dated pollen diagrams from 1985 m, 2050 m, and at the tree line at 2150 m asl show the vegetational succession in the central Altai Mountains since 16 cal ka BP. Pioneer vegetation after deglaciation was recorded first at the lowest site. Subsequently, dense dry steppe vegetation developed coincident with the change from silt to organic sediments at the two lower sites, but silt lasted longer at the highest site, indicating the persistence of bare ground there. Forests of Pinus sibirica, Pinus sylvestris, Picea obovata, Larix sibirica, Abies sibirica, and Betula pendula started to develop about 12 cal ka BP with the change to a warmer and wetter climate at the beginning of the Holocene. Results indicate that the timberline did not rise above the highest site. Mesophilous dark-coniferous forests were fully developed by 9.5 cal ka BP. The role of Abies and Picea decreased by about 7.5 cal ka BP suggesting cooler climate, after which the forests changed little until today. The vegetational development in this portion of the central Altai Mountains is compatible with that described in neighbouring areas of the Altai, southern Siberia, Mongolia, and Kazakhstan.
Two lakes of glacial origin (Grusha at 2413m and Akkol at 2204m) are located on a broad high-mountain plateau on the dry eastern end of the Russian Altai Mountains in the Republic of Tuva, just north of Mongolia. The present vegetation of the area is an open high-mountain tundra–steppe mosaic, with patches of Larix and Pinus sibirica forests on north-facing slopes 30km northwest of the lakes. Alpine meadows occur near streams and snow patches. Pollen diagrams and radiocarbon dates (16 for Grusha and 12 for Akkol) were used to reconstruct the vegetational history since the last glaciation. The core from Grusha contains about 50cm of Late Glacial sediment of relatively low organic content, mostly correlated with the Younger Dryas episode because of the high percentages of Artemisia , Gramineae, and Chenopodiaceae, along with a diversity of non-arboreal pollen types indicating tundra–steppe and meadow-steppe. In the earliest Holocene, starting with increased organic matter at about 195cm (12,000cal. yr BP), the Artemisia –Gramineae–Chenopodiaceae pollen assemblage continued, along with an increase in shrub Betula but without the diversity of minor non-arboreal types. The interpretation of dry and warm climate at this time is supported by the unconformity at Akkol, implying a dried lake. Then after about 1000years the increase of Pinus sibirica , P. sylvestris , Picea obovata , and Abies sibirica suggests that forests developed in response to increased humidity, first at the higher-elevation Grusha, and then at Akkol. After about 6000cal. yr BP the role of forests decreased sharply in the area. The Picea and Abies components almost disappeared, as they did also in more westerly areas of the Altai Mountains. Steppe elements increased along with alpine herbs, especially after 2000cal. yr BP as a result of cooling or increased aridity, as well as probable human activity. Correlation of the vegetation sequence for the Tuva sites with those to the west in the central Altai Mountains indicates that the Late Glacial open landscapes persisted in the earliest Holocene but then were invaded by coniferous forests as a result of increased moisture and temperature associated with Atlantic storm systems as well as with insolation-enhanced Asian monsoon. Cooling and drying after about 6000cal. yr BP brought the decline of Abies and Picea and the expansion of tundra–steppe.
On the basis of pollen and spore analyses and radiocarbon dating of peat deposits of Lugovoe Mire in southern Middle Siberia, changes of vegetation and climate of the Western Sayan Mts and the Khakasia Republic (Russia) since 6000yr 14 C BP (5000cal yr BC) are found to correspond with the development of archaeological cultures and with the pollen-based palaeoclimatic reconstruction of Levina and Orlova (1993) constructed for the forest-steppe zone of the south of West Siberia. Three phases in the development of the regional vegetation ( Abies , Betula , and Pinus ) are distinguished in the pollen diagram of Lugovoe Mire, which form the environmental background for the archaeological cultures developed in this region. The first penetration of ancient hunting–fishing tribes into this area occurred during the ‘ Abies stage’ of the vegetation. Bronze Age cultures practiced agriculture and animal husbandry mostly during the ‘ Betula stage’. Beginning in the Iron Age, archaeological cultures bloomed in the study area on the background of expanding Pinus sylvestris forests. The origin of all these cultures was connected with migrations of people from the southwest or southeast. An important reason for these migrations was dry climatic phases at millennial intervals, which influenced especially strongly the more southerly homelands of the migrating ancient tribes.
We synthesize palaeoclimate records from the mid-latitude arid Asian region dominated today by the Westerlies (“arid central Asia” (ACA)) to evaluate spatial and temporal patterns of moisture changes during the Holocene. Sediment records from 11 lakes with reliable chronologies and robust proxies were selected to reconstruct moisture histories based on a five-class ordinal wetness index with assigned scores from the driest to wettest periods at individual sites for 200-year time slices. The proxies used in these records include pollen and diatom assemblages, sediment lithology, lake levels, and geochemistry (mainly isotope) data. The results of our synthesis show that ACA as a whole experienced synchronous and coherent moisture changes during the Holocene, namely a dry early Holocene, a wetter (less dry) early to mid-Holocene, and a moderately wet late Holocene. During the early Holocene most of the lakes experienced very low water levels and even dried out before ca 802ka (102ka=100002cal02a02BP). Hence the effective-moisture history in ACA is out-of-phase with that in monsoonal Asia as documented by numerous palaeoclimate records. In monsoonal Asia, a strong summer monsoon and humid climate characterized the early Holocene, and a weakened summer monsoon and drier climate prevailed during the late Holocene, which were mainly controlled by changes in low-latitude summer insolation. In contrast, we propose that the pattern of Holocene effective-moisture evolution in the westerly dominated ACA was mainly determined by North Atlantic sea-surface temperatures (SSTs) and high-latitude air temperatures that affect the availability, amount and transport of water vapor. Also, topography of the Tibetan Plateau and adjacent Asian highlands could have contributed to the intensification of dry climate in ACA during the early Holocene, as a result of strengthening the subsidence of dry air masses, associated with stronger uplift motion on the plateau by intense heating under a stronger summer insolation. Summer insolation might have played a key role in directly controlling moisture conditions in ACA but only after the northern hemisphere ice-sheets had disappeared in the mid- and late Holocene.
There are significant differences in the interpretation of the moisture (precipitation) history of arid central Asia (ACA) during the Holocene, as inferred on one hand from speleothem oxygen isotope records, and on the other from lake sediments. Here we present the results of measurements of climatically-sensitive magnetic properties and soil color from four well-dated loess-paleosol sequences from the northern slopes of the Tienshan Mountains and the Yili River valley, Xinjiang, China, in the core area of ACA. Our results demonstrate that the characteristic Holocene paleosol, indicating relatively moist conditions, generally formed after 6 ka (1 ka=1000calyr BP) in the study region, and that the accumulation of unweathered loess prevailed during the early Holocene, indicating a dry climate at that time. The magnetic proxies further reveal a trend of generally increasing moisture since the Last Glacial Maximum, with the wettest climate occurring during the late Holocene. This trend of increasing moisture during the Holocene is representative of the Xinjiang region and possibly of the whole of the core area of ACA, and is in marked contrast both to the mid-Holocene moisture maximum observed in the East Asian summer monsoon region and to the general decrease in the strength of the Indian summer monsoon since the early Holocene. Our findings are supported by the results of a climate simulation which indicate a trend of increasing summer and winter precipitation during the Holocene in the core area of ACA, caused mainly by an increase in the strength of the westerlies effected by an increasing latitudinal insolation gradient and by a negative trend of the Arctic Oscillation (AO) or North Atlantic Oscillation (NAO).
Abstract The location of the Altai Mountains at the limits of both the Pacific and Atlantic influences implies that this mountain range is an important climatic boundary. Based on pollen data of 188 samples of a 390-cm core from Narenxia Peat in the southern Altai with a chronologic support of 11 accelerator mass spectrometry (AMS) dates, we reconstructed the Holocene climatic change at Narenxia Peat. The reconstruction revealed five stages of climatic change: a cold and dry latest deglacial (prior to ~11,500 cal. yr BP), a warm and wet early-Holocene (~11,500 to ~7000 cal. yr BP), a considerably cooled and dried middle Holocene (~7000 to ~4000 cal. yr BP), a resumed warm and wet late-Holocene (~4000 to ~1200 cal. yr BP), and a relatively cool and dry latest Holocene (past ~1200 years). The reconstructions of mean annual temperature (MAT) and mean annual precipitation (MAP) from Narenxia Peat well resemble the reconstructions of North Atlantic Oscillations (NAO) and El Ni outhern Oscillations (ENSO). The resemblance implies that the Holocene millennial-scale changes in MAT and MAP in the Altai might have been causally associated with the variations in NAO and ENSO.
Sedimentological, geochemical and palynological data from Wulungu Lake in northern Xinjiang, China, are used to reconstruct environmental and climate changes since 9550 cal yr BP. High abundance of Sparganium and Poaceae, low Md (median diameter) and u03b413Corganic values indicate aridity between 9550 and 6730 cal yr BP. High Md and u03b413Corganic values, and the prevalence of desert-steppe and steppe vegetation between 4200 and 560 cal yr BP, indicate that effective moisture increased after 6730 cal yr BP, peaking at 4200 and 560 cal yr BP. Low Md values, a negative excursion of u03b413Corg, and the transition from steppe to desert vegetation since 560 cal yr BP reflect a decrease in effective moisture during the latest Holocene. Late Holocene human activities were indicated by sharp increase in the abundance of Pediastrum then. Variations in carbonate contents indicate that temperature was generally high between 9550 and 7740 cal yr BP, low between 7740 and 6730 cal yr BP, intermediate between 6730 and 560 cal yr BP, and low during the last 560 yr. Regional comparison indicates that the Asian monsoon did not extend to Wulungu Lake and westerlies were the main factor in determining the moisture availability during the Holocene.
This study presents the results of the palynological and diatom analyses of the sediment core recovered in Hoton-Nur Lake (48°37′18″N, 88°20′45″E, 208302m) in 2004. Quantitative reconstruction of the Holocene vegetation and climate dynamics in the semiarid Mongolian Altai suggests that boreal woodland replaced the primarily open landscape of northwestern Mongolia at about 1002kyr02BP (102kyr02=02100002cal02yr) in response to a noticeable increase in precipitation from 200–25002mm/yr to 450–55002mm/yr. A decline of the forest vegetation and a return to a predominance of open vegetation types occurred after 502kyr02BP when precipitation sums decreased to 250–30002mm/yr. Prior to 11.502kyr BP diatom concentrations are relatively low and the lake is dominated by planktonic Cyclotella and small Fragilariaceae, suggesting the existence of a relatively deep and oligotrophic/mesotrophic lake. The great abundance of Staurosirella pinnata from the beginning of the record until 10.702kyr02BP might imply intensified erosion processes in the catchment and this is fully consistent with the presence of scarce and dry vegetation and the generally arid climate during this period. From about 10.702kyr02BP, more planktonic diatom taxa appeared and increased in abundance, indicating that the lake became more productive as diatom concentration increased. This change correlates well with the development of boreal woodland in the catchment. Decrease in precipitation and changes in the vegetation towards steppe are reflected by the rapid increase in Aulacoseira distans from about 502kyr02BP. The Holocene pollen and diatom records do not indicate soil and vegetation cover disturbances by the anthropogenic activities, implying that the main transformations of the regional vegetation occurred as a result of the natural climate change. Our reconstruction is in agreement with the paleomonsoon records from China, demonstrating an abrupt strengthening of the summer monsoon at 1202kyr02BP and an associated increase in precipitation and in lake levels between 11 and 802kyr02BP, followed by the stepwise attenuation of the monsoon circulation and climate aridization towards the modern level. The records from the neighboring areas of Kazakhstan and Russia, situated west and north of Hoton-Nur, demonstrate spatially and temporally different Holocene vegetation and climate histories, indicating that the Altai Mountains as a climate boundary are of pivotal importance for the Holocene environmental and, possibly, habitation history of Central Asia.
The regional climate patterns have been generally dominated by alternations of warm-dry and cold-wet episodes during the Holocene that were quite different from the warm-wet and cool-dry episodes in the Asian summer monsoon region. Regional comparisons indicate that the climate changes in arid central Asia have been mainly influenced by the North Atlantic Ocean sea surface temperatures (SSTs) via the westerlies. However, owing to the mountainous character of the study areas, glacial meltwater, and other local factors, the climate changes in the Altai Mountains region have not always been concordant with variations of North Atlantic Ocean SSTs. We postulate that the history of moisture balance between regional precipitation, glacier and snow meltwater, and evaporation has been modulated by air temperatures that were mainly influenced by changes in the summer insolation of the Northern Hemisphere.
Based on the review of 26 high-standard Holocene climatic reconstructions (mainly pollen-based) from the Mongolian Plateau and its surrounding areas, temporal and spatial patterns of the Holocene moisture evolution are synthesized. The regionally-averaged moisture history from the summer monsoon-influenced semiarid belt in China (i.e., Region A) demonstrates that the moisture index curve is broadly in agreement with the synthesized East Asian Monsoon Strength curve, both following the general trend of the West Tropical Pacific SST that is in turn the delayed response to the northern hemispheric summer solar insolation. The regionally-averaged moisture indices from the winter monsoon-dominated southern Siberia including Lake Baikal area and the Altai Mountains (i.e., Region B) exhibit a general declining trends since 10.6 cal. kyr BP, being largely consistent with the trends of the annual precipitation and the warm-season temperature in the Russian Plain. The consistency might be attributable to the Holocene declining trend of the warm-season temperature in North Atlantic region. The predominant feature of the regionally-averaged moisture index from the westerlies-affected northern Xinjiang (i.e., Region C) is a persistent increasing trend since cal. kyr BP. The wetting trend of northern Xinjiang during the past 8000 years might be attributable to the increasing trend of winter insolation and to the associated increasing trend of cold-season temperature in northwestern Europe. The chronological correspondences between dry phases and warm intervals in the arid areas of the Mongolian Plateau (i.e., northern Mongolian Plateau within Mongolia and southern Mongolian Plateau within China, Region D) lend a support to the proposal that the mid-Holocene dry phase was most likely the result of mid-Holocene high warm-season temperature.
We analyzed the changes in precipitation regime in the Altai Mountains for 1959-2014 and estimate the influence of atmospheric circulations on these changes. Our study showed that during last 56 years the changes in the precipitation regime had a positive trend for the warm seasons (April-October), but weakly positive or negative trends for the cold seasons (November-March). It was found that these changes correspond to the decreasing contribution of “Northern meridional and Stationary anticyclone (Nm-Sa)” and “Northern meridional and East zonal (Nm-Ez)” circulation groups and to the increasing contribution of “West zonal and Southern meridional (Wz-Sm)” circulation groups, accordingly to the Dzerdzeevskii classification. In addition, it was found that the variation of precipitation has a step change point in 1980. For the warm seasons, the precipitation change at this point is associated with the reduced influence of “West zonal (Wz)”, “Northern meridional and Stationary anticyclone (Nm-Sa)” and “Northern meridional and Southern meridional (Nm-Sm)” circulation groups. For the cold seasons, a substantial increase of “Wz-Sm” and a decrease of “Nm-Sa”, “Nm-Ez” circulation groups are responsible for the precipitation change in the two time periods (1959-1980 and 1981-2014).
A high-resolution pollen record from Lake Teletskoye documents the climate-related vegetation history of the northern Altai Mountain region during the last millennium. Siberian pine taiga with Scots pine, fir, spruce, and birch dominated the vegetation between ca. AD 1050 and 1100. The climate was similar to modern. In the beginning of the 12th century, birch and shrub alder increased. Lowered pollen concentrations and simultaneous peaks in herbs (especially Artemisia and Poaceae), ferns, and charcoal fragments point to colder and more arid climate conditions than before, with frequent fire events. Around AD 1200, regional climate became warmer and more humid than present, as revealed by an increase of Siberian pine and decreases of dry herb taxa and charcoal contents. Climatic conditions were rather stable until ca. AD 1410. An increase of Artemisia pollen may reflect slightly drier climate conditions between AD 1410 and 1560. Increases in Alnus, Betula, Artemisia, and Chenopodiaceae pollen and in charcoal particle contents may reflect further deterioration of climate conditions between AD 1560 and 1810, consistent with the Little Ice Age. After AD 1850 the vegetation gradually approached the modern one, in conjunction with ongoing climate warming.
A unique 800-yr-long record of annual temperatures and precipitation over the south of western Siberia has been reconstructed from the bottom sediments of Teletskoye Lake, Altai Mountains using an X-ray fluorescence scanner (XRF) providing 0.1-mm resolution timeseries of elemental composition and X-ray density (XRD). Br content appears to be broadly correlative with mean annual temperature variations because of changes in catchment vegetation productivity. Sr/Rb ratio reflects the proportion of the unweathered terrestrial fraction. XRD appears to reflect water yield regime and sediment flux. Sedimentation is rather continuous because annual clastic supply and deposited mass are the same. The artificial neural networks method was applied to convert annual sedimentary time-series of XRD, Br content, and Sr/Rb ratio to annual records of temperature and precipitation using a transfer function. Comparison of these reconstructed Siberian records with the annual record of air temperature for the Northern Hemisphere shows similar trends in climatic variability over the past 800yr. Estimated harmonic oscillations of temperature and precipitation values for both historical and reconstructed periods reveal subdecadal cyclicity.
We present new tree-ring width, δ 13 C, and δ 18 O chronologies from the Koksu site (49°N, 86° E, 2,20002m asl), situated in the Russian Altai. A strong temperature signal is recorded in the tree-ring width (June-July) and stable isotope (July-August) chronologies, a July precipitation signal captured by the stable isotope data. To investigate the nature of common climatic patterns, our new chronologies are compared with previously published tree-ring and stable isotope data from other sites in the Altai region. The temperature signal preserved in the conifer trees is strongly expressed at local and regional scales for all studied sites, resulting in even stronger temperature and precipitation signals in combined average chronologies compared to separate chronologies. This enables the reconstruction of June-July and July-August temperatures for the last 20002years using tree-ring and stable carbon isotopes. A July precipitation reconstruction based on oxygen isotopic variability recorded in tree-rings can potentially improve the understanding of hydrological changes and the occurrence of extreme events in the Russian Altai.
The goal of this research report is to describe annual precipitation reconstruction from trees on three sites in the Abakan region, located in the Minusinsk Depression, at the confluence of the Yenisei and Abakan Rivers, Russia. The study was performed during the 4annual international summer course “Tree Rings, Climate, Natural Resources and Human Interaction” held in Abakan, 5-19 August 2013. The reconstruction, for the 12-month total precipitation ending in July of the growth year, is based on a reliable and replicable statistical relationship between precipitation and tree-ring growth, and shows climate variability on both interannual and interdecadal time scales. The regional tree-ring chronology accounts for 56% of the variance of observed annual precipitation in a linear regression model, with the strongest monthly precipitation signal concentrated in May and June of the current growing season. Composite 50002mb height-anomaly maps suggest that the tree-ring data from this site, supplemented by other regional tree-ring data, could yield information on long-term atmospheric circulation variability over the study area and surrounding region.
The temporal variation of accumulation and temperature in the Siberian Altai were investigated using a 86 m long ice core from Belukha glacier (49°48'26″N, 86°34'43″E, 4062 m a.s.l.), covering the time period 1816 to 2001. As temperature-sensitive parameters the melt percent profiles and the stable oxygen isotopes (δO) were evaluated, representing summer season and March to November temperatures, respectively. The accumulation record showed no long-term trend and only minor deviations of limited duration from the accumulation average of 0.5 m water equivalent/y (weq./y) were observed. In contrast, the two temperature proxies indicate a strong warming trend in the order of 1.6 ± 0.4°C and 1.7 ± 1.1°C over the last century, inferred from melt percentages and the δO record, respectively, and 2.5 ± 1.7°C since the mid-19th century, inferred from the δO record. This reflects an amplified regional climate response following the Little Ice Age (LIA) as compared to the Northern Hemisphere average, most probably caused by the strong continentality of the Siberian Altai region. The sudden onset of large melt features since 1988 indicates that the upper reaches of Belukha glacier are experiencing a change from the recrystallization to the cold-infiltration zone that now allows for multiannual percolation of meltwater, implying that the conservation of accumulation and geochemical properties, including those providing temperature proxies, is currently endangered.
We developed six tree-ring width chronologies of Siberian spruce ( Picea obovata ) from the low elevation forest of the southern Altay Mountains in northern Xinjiang, China. Although the six chronologies come from different sampling sites, significant correlations existed among the chronologies ( r 02≥020.477), and the first principal component (PC1) accounted for 72.2% of total variance over their common period 1825–2010. Correlation response analysis revealed that radial growth of Siberian spruce is mainly limited by a 12-month precipitation starting from July of the previous year to June of the current year. We therefore developed a July–June precipitation reconstruction spanning 1825–2009, which explained 65.5% of the instrumental variance for the period 1962–2009. The information of our precipitation reconstruction suggested that dry conditions existed for the periods 1829–1838, 1852–1855, 1876–1888, 1898–1911, 1919–1923, 1932–1936, 1943–1955, 1963–1968, 1973–1984 and 2007–2009, and wet conditions for the periods AD 1825–1828, 1839–1851, 1856–1875, 1889–1897, 1912–1918, 1924–1931, 1937–1942, 1956–1962, 1969–1972 and 1985–2006. Spatial climate correlation analyses with gridded land surface data revealed that our precipitation reconstruction contains a strong precipitation signal for the Altay Mountain ranges. Our reconstruction agreed with the moisture-sensitive tree ring width series of Siberian larch from the Altay Mountains of Mongolia on a decadal timescale. In addition, in contrast to a drying trend in north central China, a clear wetting trend has occurred in the southern Altay Mountains since 1980s.
Based on the significant positive correlations between the regional tree-ring width chronology and local climate data, the total precipitation of the previous July to the current June was reconstructed since AD 1760 for the northwestern Chinese Altay. The reconstruction model accounts for 40.7 % of the actual precipitation variance during the calibration period from 1959 to 2013. Wet conditions prevailed during the periods 1764-1777, 1784-1791, 1795-1805, 1829-1835, 1838-1846, 1850-1862, 1867-1872, 1907-1916, 1926-1931, 1935-1943, 1956-1961, 1968-1973, 1984-1997, and 2002-2006. Dry episodes occurred during 1760-1763, 1778-1783, 1792-1794, 1806-1828, 1836-1837, 1847-1849, 1863-1866, 1873-1906, 1917-1925, 1932-1934, 1944-1955, 1962-1967, 1974-1983, 1998-2001, and 2007-2012. The spectral analysis of the precipitation reconstruction shows the existence of some cycles (15.3, 4.5, 3.1, 2.7, and 2.1 years). The significant correlations with the gridded precipitation dataset revealed that the precipitation reconstruction represents the precipitation variation for a large area of the northern part of inner Asia. A comparison with the precipitation reconstruction from the southern Chinese Altay shows the high level of confidence for the precipitation reconstruction for the northwestern Chinese Altay. Precipitation variation of the northwestern Chinese Altay is positively correlated with sea surface temperatures in tropical oceans, suggesting a possible linkage of the precipitation variation of the northwestern Chinese Altay to the El Ni o-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). The synoptic climatology analysis reveals that there is the relationship between anomalous atmospheric circulation and extreme climate events in the northwestern Chinese Altay.
<FONT face=Verdana>根据采自阿勒泰西部地区5个采点的树木年轮样本,建立了该地区的树轮年表. 通过相关普查发现,其差值年表序列与该地区当年6~9月的降水量存在明显的负相关关系,且具有明确的树木生理学意义. 用沙勒哈(t,t+1)两个树轮差值年表序列可较好地重建该地区1481-2004年524a来的当年6~9月的降水量,且经过交叉检验表明重建方程稳定可靠. 分析发现,阿勒泰西部地区524a来的重建降水量序列具有9个偏干阶段和9个偏湿阶段,并且具有34.8a、5.0~5.1a、4.3~4.4a、3.9~4.0a、3.7a和3.4a的显著干湿变化准周期. 重建降水量序列在1518年、1548年、1634年、1765年、1856年前后发生过突变. </FONT>
[
张同文
,
袁玉江
,
喻树龙
,
等
.
树木年轮重建阿勒泰西部1481-2004年6-9月降水量序列
.
冰川冻土,
2008
,
30
(
4
):
659
-
667
.]
<FONT face=Verdana>根据采自阿勒泰西部地区5个采点的树木年轮样本,建立了该地区的树轮年表. 通过相关普查发现,其差值年表序列与该地区当年6~9月的降水量存在明显的负相关关系,且具有明确的树木生理学意义. 用沙勒哈(t,t+1)两个树轮差值年表序列可较好地重建该地区1481-2004年524a来的当年6~9月的降水量,且经过交叉检验表明重建方程稳定可靠. 分析发现,阿勒泰西部地区524a来的重建降水量序列具有9个偏干阶段和9个偏湿阶段,并且具有34.8a、5.0~5.1a、4.3~4.4a、3.9~4.0a、3.7a和3.4a的显著干湿变化准周期. 重建降水量序列在1518年、1548年、1634年、1765年、1856年前后发生过突变. </FONT>
Eight tree-ring chronologies in middle and eastern Altay Prefecture were established. The correlation between the climatic data and the chronologies was analyzed. It is found that the standardized chronology series positively correlates with the snowfall from January to February in the prefecture, and has obvious tree physiological significance. With the three chronologies YHN(t),ZLS(t+2) and HLE(t+3), the 189 a (1818-2006) snowfall from January to February can be better reconstructed, and the reconstructed equation is reliable. It is found that: 1) The reconstructed snowfall has five wetter periods above their mean and five drier periods below their mean. 2) The reconstructed series has significant cycles of 2.4 a, 3.3~3.4 a and 63 a periods. 3) The abruptly change of the reconstructed snowfall series occurred in 1847, 1901, 1930 and 1986, of which the change was from more to less in 1847 and 1930, while the change was from less to more in 1901 and 1986.
[
胡义成
,
魏文寿
,
袁玉江
,
等
.
基于树轮的阿勒泰地区1818-2006年1-2月降雪量重建与分析
.
冰川冻土,
2012
,
34
(
2
):
319
-
327
.]
Eight tree-ring chronologies in middle and eastern Altay Prefecture were established. The correlation between the climatic data and the chronologies was analyzed. It is found that the standardized chronology series positively correlates with the snowfall from January to February in the prefecture, and has obvious tree physiological significance. With the three chronologies YHN(t),ZLS(t+2) and HLE(t+3), the 189 a (1818-2006) snowfall from January to February can be better reconstructed, and the reconstructed equation is reliable. It is found that: 1) The reconstructed snowfall has five wetter periods above their mean and five drier periods below their mean. 2) The reconstructed series has significant cycles of 2.4 a, 3.3~3.4 a and 63 a periods. 3) The abruptly change of the reconstructed snowfall series occurred in 1847, 1901, 1930 and 1986, of which the change was from more to less in 1847 and 1930, while the change was from less to more in 1901 and 1986.
<p>利用阿尔泰山南坡东、中、西部3个样点的西伯利亚落叶松树轮<em>δ</em><sup>13</sup>C序列,结合阿勒泰地区7个气象站降水资料分析表明,树轮<em>δ</em><sup>13</sup>C序列对阿尔泰山南坡夏季降水有较好的响应,最高相关系数可达到-0.682(<em>p</em><0.0001).利用回归方法重建了过去160年来阿尔泰山南坡夏季降水量.阿尔泰山南坡夏季降水在1850-1871年偏多,1872-1956年经历了长期的干旱,20世纪60年代至今,随着新疆整体气候的暖湿化,阿尔泰山南坡经历了较长的湿润期.重建的夏季降水与上年冬季北极涛动(AO)有较好的相关性,北极涛动可能对阿尔泰山南坡过去160年降水有较大影响.阿尔泰山南坡过去160年夏季降水变化存在11 a(95% )、2.7 a (95%)、2.4 a(95%)、2.1 a(99%)和2.0 a(99%)的准周期变化.</p>
[
张瑞波
,
尚华明
,
袁玉江
,
等
.
.
地理学报,
2017
,
72
(
1
):
18
-
26
.]
本文结合资料分析和文献阅读,对全球气候变化背景下的中亚天山山区水文、水资源变化进行了讨论分析。在全球升温滞缓背景下,中亚天山山区在过去的10余年,气温却一直处于高位态波动状态;气候变暖及持续高位态波动加剧了山区冰川和积雪等固态水体的消融,导致山区降雪率降低,天山山区降雪率从1960-1998年的11%~24%降低到2000年以来的9%~21%,有97.52%的冰川表现为退缩状态,水储量呈明显减少趋势,减小幅度约为-3.72 mm/a;气候变暖直接影响区域水循环和水系统的稳定性,引起径流补给方式和水资源数量的改变,加大了水资源时空分布的不确定性。天山山区在短时期内因冰雪融水增多,会出现径流量增加现象。但在未来气候持续变暖、降水条件维持不变的条件下,河川径流量将会出现减少趋势。
Based on the data of five observed meteorological elements (temperature, precipitation, wind speed, sunshine duration, and relative humidity) from 22 stations, the paper investigated the climate variations in northern Xinjiang over the past 50 years. The analytical results showed that both the temperature and the precipitation have increased significantly (0.3502°C/1002y, 11.202mm/1002y) during the period of 1960–2011. An abrupt change was detected to have occurred in 1986 for temperature and in 1987 for precipitation. Autumn was the season when the temperature increased most dramatically, and winter and autumn were the seasons when the precipitation increased most dramatically. The twenty years after 1990 were the warmest and wettest two decades of the past 6550 years, but the warming and wetting paces have slowed down during the same period. The results also showed that the mean annual minimum temperature increased more dramatically than the mean annual maximum temperature, resulting in a greatly reduced diurnal range. The reasons or mechanisms for rising trend of temperature during the past 50 years and also for the faster rising rate of the temperature in northern Xinjiang and the adjacent areas have been reasonably explored in published literature. However, the reasons or mechanisms for the rising trend of the past 50-year precipitation in northern Xinjiang and the adjacent areas have not been reasonably explored. This wetting trend has not extended further to the surrounding areas including Republic of Mongolia, major part of North China, and five republics of the former Soviet Union, and the need is thus pressing to explore the reasons or mechanisms behind this relatively “localized” wetting trend.
This paper presents a new palynological record from a 14602cm long finely laminated sediment core obtained in 2009 from the deep-water meromictic Lake Shira (54°30′38″N, 90°12″09′E; ca. 35302m02a.s.l.) situated in the Khakassian steppe region of southern Siberia between the rivers Ob' and Yenisei. The area is rich in lakes and represents an exceptionally well preserved sequence of Bronze and Iron Age archeological cultures. Little is known about the changes in vegetation and climate of the region during the Holocene. The palynological analysis of the core allows us to partly fill up this gap in current knowledge. The record of pollen and non-pollen palynomorphs presented here covers the past 245002year interval with an average resolution of 2202years. The results obtained support the interpretation that the late Holocene vegetation changes around Lake Shira are mainly associated with large-scale atmospheric circulation processes controlling the regional water balance rather than with human activities. An attempt to trace human impact in the pollen assemblages provides no clear evidence for anthropogenic activity, except for the last few decades since ca. 1955, though the region has a long history of mobile pastoralists. For explanation of decadal-scale changes in the regional vegetation cover, the Artemisia /Chenopodiaceae (A/C) pollen ratio proved to be a reliable indicator of effective moisture availability. Using available fossil and published instrumental data our study suggests a link between the North Atlantic warmer/colder temperatures and higher/lower atmospheric precipitation (or moisture availability) in southern Siberia at multi-decadal to centennial scales.
ABSTRACT A 2700-year-old peat core from the southern West Siberian Lowlands was used to reconstruct past water-table depth using testate amoeba analysis and to compare hydrological changes with temperature variations associated with the Medieval Climate Anomaly, ‘Little Ice Age’, and 20th-century warming. The robustness of water-table results was assessed using comparisons of four separate transfer functions, a testate amoeba reconstruction from an additional site in southern West Siberia, and an independent hydrological proxy of the δ13C values of Sphagnum remains from the same core. The paleohydrology results were robust in that (1) all four transfer functions returned similar results, (2) both peatland sites displayed very similar water-table fluctuations despite their distance from each other, and (3) Sphagnum δ13C values showed similar overall changes as the testate amoeba-inferred hydrology, but at a coarser temporal resolution. When comparing reconstructed hydrology in southern West Siberia to Northern Hemisphere temperatures, we found that during most of the record warmer time intervals tended to be wet locally and cooler time intervals tended to be dry including during the Medieval Climate Anomaly (~1150-650 cal. BP). This pairing continued until the ‘Little Ice Age’ (~650-100 cal. BP) when conditions became cool and wet, and recently, conditions have become warm again, but unlike the earlier wet interval, the peatlands have dried. Drier conditions shown by the water-table depth reconstruction suggest that future warming may continue the drying of southern peatland surfaces in the West Siberian Lowlands and may promote peat carbon respiration.
We have studied diatom assemblages of a 42-cm-long sediment core obtained from Lake Ailike in northern Xinjiang of China to reconstruct the hydrological and ecological variations of the past 130 years. Three environmental parameters of lake water (i.e., diatom-inferred pH, diatom-inferred total phosphorus and diatom-inferred conductivity) were estimated by comparing the fossil diatom assemblages from the Lake Ailike core with the modern diatom assemblages in the European Diatom Database. The reconstruction exhibited two major stages: stage A (1884–1960) was a “natural” stage and stage B (1960–2013) was a “human” stage. The “natural” stage can be further divided into two sub-stages: A-1 (1884–1920) was characterized by an averagely low lake area and A-2 (1920–1960) was a stably high lake-area period. The comparison between the reconstructed lake-area variations from Lake Ailike with the treering-recorded Palmer Drought Severity Index (PDSI) variations from nearby Hutubi shows that the low lake area from 1884 to 1920 was correspondent with a dry period and that the high lake area from 1920 to 1960 with a wet period. The similarity between PDSI from Hutubi and the Atlantic Multidecadal Oscillation (AMO) implies a climatic linkage. The linkage is revealed by the tight in-phase relationship between AMO and SWP (Siberian warm-season precipitation), that is, the AMO-promoted SWP might have extended its influence to northern Xinjiang. The “human” stage can also be divided into two sub-stages: B-1 (1960–2000) was a regressing stage and B-2 (2000–2013) was a transgressing stage. The man-made regression led to dramatic increases in TP of the lake water, TOC and TN of the sediments and also in the resulted decrease in lake water pH. Fortunately, the Irtysh-Karamay Canal started to inject water into the lake in 2001, resulting in a constant expansion of lake-covered area and also in a constant improvement of ecological conditions.
Solar irradiance changes are thought to play an important role in natural climate variability. How solar activities affected hydrological changes in westerly-controlled arid central Asia (ACA) on decadal/centennial timescales remains poorly investigated, due to lack of high-quality records. Here we present high-resolution multi-proxy records of lake level changes, and thus effective moisture fluctuations, over the last millennium, from a shoreline sediment core retrieved from Lake Manas, northwestern China. Besides generally confirmed relatively wet conditions during the cool Little Ice Age, records of the geophysical and geochemical indicators, including lightness, calcium counts, and C37 alkenone contents, consistently show substantial and frequent lake level fluctuations, and more importantly, resemble solar irradiance changes. Further, the ~11-year Schwabe cycle, ~70-100-year Gleissberg cycle, and relatively weak spectral power in between, as characters in the sunspot number record, together with the ~200-year Suess-de Vries cycle revealed in the reconstructed total solar irradiance records, are all evident in the higher-resolution calcium and lightness records. Together, our records clearly demonstrate solar imprints on effective moisture fluctuations in ACA over the last millennium, and the occurrence of the Schwabe cycle even during the solar minima.
Abstract Ma, L., Wu, J., Yu, H., Zeng, H. & Abuduwaili, J. 2011: The Medieval Warm Period and the Little Ice Age from a sediment record of Lake Ebinur, northwest China. Boreas , Vol. 40, pp. 518–524. 10.1111/j.1502-3885.2010.00200.x. ISSN 0300-9483. Lake Ebinur, Xinjiang, northwest China, is a closed-basin, shallow lake that responds rapidly to changes in the ratio of precipitation to evaporation (P/E). A sediment record spanning the last 1500 years was obtained from the lake. We used δ 18 O and δ 13 C in bulk carbonate, and δ 13 C of organic matter in the lake sediments to infer environmental changes in the Ebinur region during the Medieval Warm Period (MWP) and the Little Ice Age (LIA). Decreased δ 18 O values of carbonate largely reflect an enhanced P/E ratio within the basin and a higher lake level. Bulk carbonates with higher δ 13 C values are deposited during periods when lake-water pH is high, while lower δ 13 C values reflect a lower pH in the water column. δ 13 C in organic matter is associated with the amount of precipitation. The results indicate that the Ebinur region experienced a dry MWP and a wet LIA, although the MWP and LIA were warm and cold periods, respectively, as expected. Furthermore, the MWP and LIA were hydrologically complex and cannot be characterized as uniformly wet or dry. Peak wet periods are recorded in the sediment core around AD 1000, 1400 and 1700, and a dry event also occurred in the period of temperature change within the LIA (cold to warm around AD 1500). A comparison of the Lake Ebinur data with proxy records for the strength of the Siberian High and climate proxy indicators suggests that precipitation in the Ebinur region was a consequence, in part, of an enhanced Siberian High during the LIA.
Short sediment cores retrieved from Bosten Lake, the largest inland freshwater lake in China, were used to explore humidity and precipitation variations in arid central Asia during the past millennium. The chronology of the cores was established using 137Cs, 210Pb and AMS 14C dating re- sults. Multi-proxy high-resolution analysis, including pollen ratios of Artemisia and Chenopodiaceae (A/C), carbonate content and grain size, indicates that the climate during the past millennium can be divided into three stages: a dry climate between 1000 1500 AD, a humid climate during the Little Ice Age (LIA) (c. 1500 1900 AD), and a warm dry period after 1900 AD. On centennial timescales, the climate change in northwestern China during the past 1000 years is characterized by oscillations between warm-dry and cold-humid climate conditions. All the proxies changed significantly and indi- cate increased precipitation during the LIA, including increased pollen A/C ratios and pollen concen- trations, decreased carbonate content and increased grain size. The humid period during the LIA re- corded by the Bosten Lake sediments is representative of arid central Asia and is supported by nu- merous records from other sites. During the LIA, the water runoff into the Keriya River and Tarim River in the Tarim Basin increased, while the ice accumulation in the Guliya ice core increased. Additionally, the lake levels of the Aral and Caspian Sea also rose, while tree-ring analysis indicates that precipita- tion increased. We hypothesize that both the lower temperature within China and the negative anomalies of North Atlantic Oscillation (NAO) during this period may have contributed to the humid climate within this area during LIA.
The degree to which warming of the planet will alter Asia's water resources is an important question for food, energy, and economic security. Here we present geological evidence, underpinned by radiometric dating and dendrochronology, and bolstered by hydrological modeling, indicating that wetter-than-present conditions characterized the core of the inner Asian desert belt during the Little Ice Age, the last major Northern Hemispheric cold spell of the Holocene. These wetter conditions accompanied northern mid-latitude cooling, glacier expansion, a strengthened/southward-shifted boreal jet, and weakened south Asian monsoons. We suggest that southward migration of grasslands in response to these wetter conditions aided the spread of Mongol Empire steppe pastoralists across Asian drylands. Conversely, net drying over the 20th century has led to drought that is unprecedented for the past 830 years, and that could intensify with further heating of the Asian continent.
On the bases of analytical data of an 850-cm-long sediment core collected from Balkhash Lake with a chronological control of seventeen AMS dates, this research reconstructed the lake salinity using carbonate content and the oxygen isotopic composition as proxies and reconstructed the basin-wide moisture using A/C ratio and pollen concentration as proxies. Basin-wide mean annual temperature (MAT) and mean annual precipitation (MAP) were reconstructed using climate-pollen response surface method. The reconstruction appears to be supportive to the early proposition that the climate in the westerlies-dominated areas has been generally characterized by cool-wet and warm-dry modes. Balkhash Basin has experienced three stages of climate change during the past 652500 years: cool-wet from 652500 to 651800cal.BP, moderate from 651800 to 650cal.BP, and cooling and wetting during the past 65650 years with the past 65100 showing warming and drying. The moisture evolution has closely followed the MAP variation and the MAT must have modulated the moisture evolution through controlling the evaporation. The first-order variation in lake salinity has been controlled by basin-wide temperature, i.e., low temperature raises the salinity level in the lake through reducing the ice-melt water supply to the lake. The second-order variation in the lake salinity seems to be modulated by pronounced variations in basin-wide moisture. Those low-amplitude variations in basin-wide moisture levels left no detectable imprints in lake salinity proxy records.
61Multi-proxy record with high resolution of central Mongolia in the last 1200 years.61Relative wet climate during the Little Ice Age was found in central Mongolia.61The monsoon–westerlies transition area shows great climate variability.61The driest condition occurred since the last 50 years in China and Mongolia.
We present a high resolution record of δ 13 C org variation from two loess sequences in central Kazakhstan. The variation shows that the vegetation was persistently dominated by C 3 plants over the past ca. 46,00002yr. The δ 13 C org signature was most likely an indicator of moisture and the moisture variation in central Kazakhstan was associated with the precipitation in Western Europe. The δ 13 C org indicated that moisture variation exhibited five stages: decreasing during stage 1 (ca. 46,000–ca. 31,50002yr BP), increasing during stage 2 (ca. 31,500–ca. 25,50002yr BP), again decreasing during stage 3 (ca. 25,500–ca. 19,00002yr BP), fluctuating along a constant line during stage 4 (ca. 19,000–ca. 500002yr BP) and increasing during stage 5 (last ca. 500002yr). Our comparison demonstrated a general similarity between the δ 13 C org -indicated moisture variation in central Kazakhstan and the reconstructed precipitation variation in Western Europe. The similarity implies that the moisture of the past ca. 46,00002yr in central Kazakhstan has been controlled or modulated by westerlies that brought water vapor from the North Atlantic not only to Western Europe but also to central Kazakhstan.
A detailed and well-dated proxy record of summer rainfall variation in arid Central Asia is lacking. Here, we report a long-term, high resolution record of summer rainfall extracted from a peat bog in arid eastern-Central Asia (AECA). The record indicates a slowly but steadily increasing trend of summer rainfall in the AECA over the past 8500 years. On this long-term trend are superimposed several abrupt increases in rainfall on millennial timescales that correspond to rapid cooling events in the North Atlantic. During the last millennium, the hydrological climate pattern of the AECA underwent a major change. The rainfall in the past century has reached its highest level over the 8500-year history, highlighting the significant impact of the human-induced greenhouse effect on the hydrological climate in the AECA. Our results demonstrate that even in very dry eastern-Central Asia, the climate can become wetter under global warming.
ABSTRACT Understanding the Holocene climate changes (especially moisture variation) and their mechanisms in the semiarid-arid Central Asia (SCA) is very important, as water availability is crucial for sustainable developments in this area. This study presents chronostratigraphy of an aeolian sedimentary sequence from Bayanbulak Basin (Xinjiang, NW China), aiming to infer the Holocene moisture history in the SCA. Luminescence dating technique was selected to construct the age framework of the study section. Since the luminescence signal intensity of quartz from the samples was too low to be detected, feldspar was used as an alternative dosimeter. A newly developed post-infrared (IR) IR-stimulated luminescence (IRSL) (pIRIR) dating protocol on K-feldspar was applied to determine the ages of samples. A set of tests on luminescence characteristics was performed and demonstrate that this method is suitable and the resultant ages are reliable. Combined with the stratigraphic investigation on the sand dune/palaeosol section, the results imply a very dry climatic condition characterized by sand dune accumulation at similar to 9-8 kyr, and a wet interval of 5-1.6 kyr when a soil layer was formed. This moisture variation pattern is consistent with that inferred from many lacustrine records in the SCA, suggesting a widespread dry period at 11-8 kyr. The present results appear to challenge a new stalagmite delta O-18 sequence, located nearby to Bayanbulak Basin, which instead suggested a humid early Holocene.
The role of pingos in the development of the Dzhangyskol lake-pingo complex, central Altai Mountains, southern Siberia. Palaeogeography, Palaeoclimatology,
Late glacial and Holocene vegetation changes on the Ulagan high-mountains plateau, Altai Mountains, southern Siberia. Palaeogeography, Palaeoclimatology,
Late Glacial and Holocene vegetational history of the Altai Mountains (southwestern Tuva Republic, Siberia). Palaeogeography, Palaeoclimatology,
Vegetation and climate in the Western Sayan Mts according to pollen data from Lugovoe Mire as a background for prehistoric cultural change in southern Middle Sibieria
Holocene moisture evolution in arid central Asia and its out-of-phase relationship with Asian monsoon history
A persistent Holocene wetting trend in arid central Asia, with wettest conditions in the late Holocene, revealed by multi-proxy analyses of loess-paleosol sequences in Xinjiang, China
Vegetation changes and associated climatic changes in the southern Altai Mountains within China during the Holocene
Holocene environmental and climatic changes inferred from Wulungu Lake in northern Xinjiang, China
Holocene environments and climate in the Mongolian Altai reconstructed from the Hoton-Nur pollen and diatom records: A step towards better understanding climate dynamics in Central Asia
Holocene climate changes in the central Asia mountain region inferred from a peat sequence from the Altai Mountains, Xinjiang, northwestern China
The 800 year long annual records of air temperature and precipitation over Southern Siberia inferred from high-resolution time-series of Teletskoye Lake sediments
... Precipitation variations of the past 200 years in the northern Altai Mountains (a. Tree-ring isotope-based precipitation during June-August
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; b. Tree-ring width-based precipitation during August-June
[
18
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; c. Glacier accumulation in Belukha Ice Core
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... Precipitation variations of the past 200 years in the northern Altai Mountains (a. Tree-ring isotope-based precipitation during June-August
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; b. Tree-ring width-based precipitation during August-June
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; c. Glacier accumulation in Belukha Ice Core
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Temporal variations of accumulation and temperature during the past two centuries from Belukha ice core, Siberian Altai
... Information of tree rings and ice core in the northern and southern Altai Mountains
... Precipitation variations of the past 200 years in the northern Altai Mountains (a. Tree-ring isotope-based precipitation during June-August
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; b. Tree-ring width-based precipitation during August-June
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; c. Glacier accumulation in Belukha Ice Core
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... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
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; b. Chen et al.
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; c. Xu et al.
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; d. Zhang et al.
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;e. Hu et al.
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) ...
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
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; c. Xu et al.
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; d. Zhang et al.
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) ...
... Information of tree rings and ice core in the northern and southern Altai Mountains
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
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; b. Chen et al.
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21
]
; c. Xu et al.
[
24
]
; d. Zhang et al.
[
25
]
;e. Hu et al.
[
23
]
) ...
... Information of tree rings and ice core in the northern and southern Altai Mountains
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
[
20
]
; b. Chen et al.
[
21
]
; c. Xu et al.
[
24
]
; d. Zhang et al.
[
25
]
;e. Hu et al.
[
23
]
) ...
Relative humidity reconstruction for northwestern China's Altay Mountains using tree-ring δ
18
O
... Information of tree rings and ice core in the northern and southern Altai Mountains
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
[
20
]
; b. Chen et al.
[
21
]
; c. Xu et al.
[
24
]
; d. Zhang et al.
[
25
]
;e. Hu et al.
[
23
]
) ...
... Information of tree rings and ice core in the northern and southern Altai Mountains
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
[
20
]
; b. Chen et al.
[
21
]
; c. Xu et al.
[
24
]
; d. Zhang et al.
[
25
]
;e. Hu et al.
[
23
]
) ...
... Precipitation variations of the past 200 years in the southern Altai Mountains (a. Chen et al.
[
20
]
; b. Chen et al.
[
21
]
; c. Xu et al.
[
24
]
; d. Zhang et al.
[
25
]
;e. Hu et al.
[
23
]
) ...
Peatland paleohydrology in the southern West Siberian Lowlands: Comparison of multiple testate amoeba transfer functions, sites, and Sphagnum δ
13
C values
Environmental variability in the monsoon-westerlies transition zone during the last 1200 years: Lake sediment analyses from central Mongolia and supra-regional synthesis
Variation in carbon isotopic composition over the past ca. 46,000 yr in the loess-paleosol sequence in central Kazakhstan and paleoclimatic significance