centennial to decadal scale monsoon precipitation variability in the semi humid region northern china during the last 1860 years records from stalagmites in huangye cave we developed a composite oxygen isotopic record of cave calcite for the last 1860 years based on three stalagmites from the huangye cave in eastern gansu province northern china the d 18 o values reflect monsoon precipitation changes with lower d 18 o values representing higher precipitation and vice versa three intervals of high precipitation were identified at ad 138 450 ad 730 1200 and ad 1860 1960 two intervals of low precipitation occurred at ad 1320 1410 and ad 1530 1860 the reconstructed monsoon precipitation variations correlate well with other records further east in the eastern yellow river basin suggesting synchronous precipitation changes during the late holocene in the semi humid region of northern china on decadal to centennial scales peak periods of warfare in dynastic transition times such as at ad 391 420 ad 601 630 ad 1111 1140 ad 1351 1380 and ad 1621 1650 correspond to sharp declines in precipitation or temperature in semi humid northern china indicating a strong connection between climatic and societal changes our study suggests that climatic deterioration in semi humid northern china has played an important role in chinese societal evolution

high resolution monsoon precipitation changes on southeastern tibetan plateau over the past 2300 years abstract climate changes on southeastern tibetan plateau have important impacts on social and economic development as well as the ecosystem of southwestern china and indo china peninsula here we collected two stalagmites from shenqi miraculous cave in southern sichuan china the stalagmite 18o record shows good coherence with local instrumental rainfall record as well as tree ring and pollen based moisture reconstructions from southeastern tibetan plateau during overlapped time periods as a result we reconstructed high resolution 4 9 yrs monsoon precipitation variations on southeastern tibetan plateau over the past 2300 years by using the combined stalagmite 18o record the result reveals an overall decreasing precipitation trend with two most notable wet periods occurred in 60 280 ad and 370 510 ad the most remarkably dry period is the recent 200 years some decadal scale wet and dry intervals were also identified the abnormal drought during 1160 1245 ad might have accelerated dali kingdom s demise at 1253 ad power spectrum analysis indicated significant 373 187 22 12 and 11 yr cycles in our stalagmite record suggesting the impact of solar activity increased monsoon precipitation on southeastern tp was observed in solar activity minima during the last millennium we further synthesized an integrated precipitation record for southwestern china and discussed spatial patterns of precipitation over china during the last two millennia the comparisons confirm a dry southern and wet northern pattern in monsoonal china during the medieval warm period and a wet southern and dry northern pattern during the little ice age and dark age cold period solar activity the strength of westerly jet and summer monsoon as well as the sst of tropical indo pacific might play important roles on the rainfall spatial patterns over monsoonal china during the last 2000 years

quantification of holocene asian monsoon rainfall from spatially separated cave records abstract a reconstruction of holocene rainfall is presented for southwest china an area prone to drought and flooding due to variability in the east asian monsoon the reconstruction is derived by comparing a new high resolution stalagmite 18 o record with an existing record from the same moisture transport pathway the new record is from heshang cave 30 27 n 110 25 e 294 m and shows no sign of kinetic or evaporative effects so can be reliably interpreted as a record of local rainfall composition and temperature heshang lies 600 km downwind from dongge cave which has a published high resolution 18 o record wang y j cheng h edwards r l he y q kong x g an z s wu j y kelly m j dykoski c a li x d 2005 the holocene asian monsoon links to solar changes and north atlantic climate science 308 854 857 by differencing co eval 18 o values for the two caves secondary controls on 18 o e g moisture source moisture transport non local rainfall temperature are circumvented and the resulting 18 o signal is controlled directly by the amount of rain falling between the two sites this is confirmed by comparison with rainfall data from the instrumental record which also allows a calibration of the 18 o proxy the calibrated 18 o record provides a quantitative history of rainfall in southwest china which demonstrates that rainfall was 8 higher than today during the holocene climatic optimum 6 ka but only 3 higher during the early holocene significant multi centennial variability also occurred with notable dry periods at 8 2 ka 4 8 4 1 ka 3 7 3 1 ka 1 4 1 0 ka and during the little ice age this holocene rainfall record provides a good target with which to test climate models the approach used here of combining stalagmite records from more than one location will also allow quantification of rainfall patterns for past times in other regions

precipitation at lake qinghai ne qinghai tibet plateau and its relation to asian summer monsoons on decadal interdecadal scales during the past 500 years knowledge of the variability of precipitation at lake qinghai and its relation to the asian summer monsoons is helpful in constraining global climatic dynamics based on the high resolution precipitation indicators of 13 c of the organic matter 13 corg c n atomic ratio and the detrended total organic carbon content tocdetrended we found that the trend of precipitation at lake qinghai is inversely correlated to that of the indian summer monsoon ism inferred from layer thickness of a stalagmite s3 in southern oman on decadal interdecadal scales the chinese drought flood d f indices which can indicate the dryness wetness over large geographic areas are also used to indicate the intensity of the monsoon rainfall the d f index of xining near lake qinghai is synchronous with those of the regions in northern china where the east asian summer monsoon easm dominates while it is anti phase with those of southwestern china where ism prevails these materials suggest that during the past 500 years the source of moisture to lake qinghai on decadal interdecadal scales is controlled mainly by the easm but not by the ism it is also suggested that the intensity of easm is inversely related to that of the ism on decadal interdecadal scales the decadal interdecadal variability of enso may be responsible for the inverse relationship between the intensity of easm and that of ism 2007 elsevier b v all rights reserved

a 780 year annually resolved record of indian ocean monsoon precipitation from a speleothem from south oman 1 meteorological records of monsoon rainfall in the indian ocean are generally less than 100 years long the relative brevity of these records makes it difficult to investigate monsoon variation on decadal and centennial timescales to determine what factors influence the intensity of rainfall on these timescales or to place possible changes in the twentieth century into a broader historical context development of a geologic proxy for rainfall that records annual variation in the monsoon over much longer time periods than are covered by instrumental records would be a significant step forward we have developed an annually resolved record of monsoon rainfall variation for the past 780 years based on annual layer thickness and stable isotope analyses of a laminated stalagmite from southern arabia our results show that monsoon variation over the past century is not outside of the range of the past 800 years decreasing monsoon rainfall over the past century is related to increasing sea surface temperature in the indian ocean spectral analyses of the record are dominated by cycles that are similar to those observed in records of solar activity on centurial timescales decadal to interannual cycles in the record appear to originate in the tropical pacific ocean index terms 3344 meteorology and atmospheric dynamics paleoclimatology 3354 meteorology and atmospheric dynamics precipitation 1854 1620 global change climate dynamics 3309 1699 global change general or miscellaneous keywords monsoon paleoclimate rainfall indian ocean speleothem oxygen isotopes

multi centennial scale changes in east asian typhoon frequency during the mid holocene abstract this study reconstructs a record of typhoon frequency over the korean peninsula during the mid holocene using mineral components and diatom assemblages in deposits of lagoon hyangho located on the east coast of the peninsula the lagoon deposits confirm the occurrence of cyclical multi centennial scale episodes of low salinization induced by typhoon derived heavy rain although shifts in typhoon frequency broadly follow el nino southern oscillation enso conditions during the holocene evidence from the typhoon induced deposits in hyangho lagoon suggests that the path of the polar westerly jet controls the effect of enso on multi centennial scale typhoon patterns across the mid latitude region of east asia the influence of enso is limited when the westerly jet passes through low latitudes fluctuations in solar activity play a key role in regulating movement of the westerly jet multi centennial scale changes in typhoon frequency in mid latitude east asia are therefore influenced by changes in solar activity and enso conditions

climate and vegetation history of the midcontinent from 75 to 25 ka a speleothem record from crevice cave missouri usa four missouri stalagmites yield consistent overlapping records of oxygen and carbon isotopic changes and provide a climate and vegetation history with submillennial resolution from 75 to 25 thousand years ago ka the thorium 230 dated records reveal that between 75 and 55 ka the midcontinental climate oscillated on millennial time scales between cold and warm and vegetation alternated among forest savanna and prairie temperatures were highest and prairie vegetation peaked between 59 and 55 ka climate cooled and forest replaced grassland at 55 ka when global ice sheets began to build during the early part of marine oxygen isotope stage 3

hydroclimatic shifts in northeast thailand during the last two millennia the record of lake pa kho the southeast asian mainland is located in the central path of the asian summer monsoon a region where paleoclimatic data are still sparse here we present a multi proxy toc c n delta c 13 bio

temperature responses to quasi 100 yr solar variability during the past 6000 years based on δ18o of peat cellulose in hongyuan eastern qinghai tibet plateau china abstract during the past 6000 years the temperature variation trend inferred from 18o of peat cellulose in a peat core from hongyuan eastern qinghai tibet plateau southwestern china is similar to the atmospheric 14c concentration trend and the modeled solar output trend the general trend of hongyuan 18o during the past millennium also coincides well with the atmospheric 14c concentration trend the 10be concentration trend in an ice core from the south pole the reconstructed total solar irradiance trend as well as the modeled solar output trend in addition temperature events also correspond well to solar perturbations during the past 6000 years therefore the driving force of holocene temperature variations should be properly ascribed to solar activity the spectrum analysis further illustrates that quasi 100 yr fluctuation of solar activity was probably responsible for temperature variations in northeast qinghai tibet plateau during the past 6000 years

a 2 326 year tree ring record of climate variability on the northeastern qinghai tibetan plateau 1 high resolution climate proxy records covering the last two millennia on the qinghai tibetan plateau are scarce yet essential to evaluation of the patterns synchroneity and spatial extent of past climatic changes including those in the medieval warm period mwp and the little ice age lia here we present a 2326 year tree ring chronology of sabina przewalskii kom for dulan area of northeastern qinghai tibetan plateau we find that the annual growth rings mainly reflect variations in regional spring precipitation the greatest change in spring precipitation during the last two millennia seems to occur in the second half of the 4th century the north atlantic mwp was accompanied by notable wet springs in the study region during a d 929 1031 with the peak occurring around a d 974 three intervals of dry springs occurred in the period of lia our tree ring data will facilitate intercontinental comparisons of large scale synoptic climate variability for the last two millennia

anthropocene archaeology of the yellow river china 5000 2000 bp in this paper we use geoarchaeological and paleoenvironmental data from three localities in the yellow river valley china taosi sanyangzhuang and the yiluo valley to argue that human activi

spatial and temporal variability in the stable isotope systematics of modern precipitation in china implications for paleoclimate reconstructions the stable isotopic composition of materials such as glacial ice tree rings lake sediments and speleothems from low to mid latitudes contains information about past changes in temperature t and precipitation amount p however the transfer functions which link 18op to changes in t or p d 18op dt and d 18op dp can exhibit significant temporal and spatial variability in these regions in areas affected by the southeast asian monsoon past variations in 18o and d of precipitation have been attributed to variations in monsoon intensity storm tracks and or variations in temperature proper interpretation of past 18op variations here requires an understanding of these complicated stable isotope systematics since temperature and precipitation are positively correlated in china and have opposite effects on 18op it is necessary to determine which of these effects is dominant for a specific region in order to perform even qualitative paleoclimate reconstructions here we evaluate the value of the transfer functions in modern precipitation to more accurately interpret the paleorecord the strength of these transfer functions in china is investigated using multiple regression analysis of data from 10 sites within the global network for isotopes in precipitation gnip 18op is modeled as a function of both temperature and precipitation the magnitude and signs of the transfer functions at any given site are closely related to the degree of summer monsoon influence 18op values at sites with intense summer monsoon precipitation are more dependent on the amount of precipitation than on temperature and therefore exhibit more negative values in the summer in contrast 18op values at sites that are unaffected by summer monsoon precipitation exhibit strong relationships between 18op and temperature the sites that are near the northern limit of the summer monsoon exhibit dependence on both temperature and amount of precipitation comparison with simple linear models 18op as a function of t or p and a geographic model 18op as a function of latitude and altitude shows that the multiple regression model is more successful at reproducing 18op values at sites that are strongly influenced by the summer monsoon the fact that the transfer function values are highly spatially variable and closely related to the degree of summer monsoon influence suggests that these values may also vary temporally since the southeast asian monsoon intensity is known to exhibit large variations on a number of timescales annual to glacial interglacial and the magnitude and sign of the transfer functions is related to monsoon intensity we suggest that as monsoon intensity changes the magnitude and possibly even the sign of the transfer functions may vary therefore quantitative paleoclimate reconstructions based on 18op variations may not be valid

hydrological changes in shuangchi lake hainan island tropical china during the little ice age abstract hydrological changes in east asia during the last millennium have been addressed by numerous earlier studies but spatial characteristics and dynamics in precipitation variations during the little ice age lia remain unclear perhaps especially due to the sparse coverage of high resolution hydrological records from tropical and sub tropical regions in east asia in this study a sediment core was obtained from shuangchi lake in northern hainan island tropical china of which geochemical proxies including the ratios of rb sr rb k zr rb and si ti were analyzed using an x ray fluorescence xrf core scanner meanwhile the grain size distribution of sediments was also determined the results show that the rb sr and rb k ratios decreased significantly during the lia whilst the zr rb and si ti ratios increased along with higher median grain size the changes of these proxies likely suggest that precipitation was enhanced during the lia in this region and this was consistent with other hydrological records from tropical southern china the synthesis of hydrological records from east asia and the tropical pacific suggest that the co existence of a contracted intertropical convergence zone itcz and strengthened pacific walker circulation pwc could contribute synchronously to the increased precipitation in the tropical region of southern china during the lia

the wet little ice age recorded by sediments in huguangyan lake tropical south china abstract although temperature decreased in a similar trend in many regions around the word during the little ice age lia the reconstructed humidity is remarkably different from region to region the precipitation history during the lia is poorly understood as compared to the temperature history in tropical south china in this study a sediment core with a length of 117 5 cm was recovered in the central part of huguangyan lake in tropical south china total organic carbon toc total nitrogen tn inorganic carbon ic and non residual strontium sr were analyzed at approximately 1 cm intervals to study the regional precipitation changes during the lia generally sr containing minerals are sensitive to chemical weathering which is dominated by the precipitation in tropical south china thus the non residual sr in huguangyan sediments can be used as an indicator of precipitation changes which is also verified by the downcore variations of toc tn and ic in huguangyan lake the non residual sr correlated positively with toc and tn but negatively with ic in the sediment profile toc tn ic and the non residual sr jointly demonstrated a wet period from ad 1500 to 1750 which corresponds to the lia coincidently both the total solar irradiance tsi and northern hemisphere temperature have the lowest values between ad 1500 and 1750 over the past millennium therefore the wet lia in tropical south china was most likely caused by the low solar irradiation during the lia the low solar irradiation likely resulted in the decrease of the northern hemisphere temperature which weakened the intensity of the east asian summer monsoon easm and synchronously moved the north edge of the asian summer monsoon southward leading to an increase in the precipitation in tropical south china

testing theoretically predicted stalagmite growth rate with recent annually laminated samples implications for past stalagmite deposition annually laminated stalagmites deposited over the last 30 160 years are analysed to determine their growth rate three natural and artificial cave sites in england france and belgium were chosen for their wide range of variability in growth rate determining variables and multiple samples were taken from each site the annual nature of laminae deposition within the stalagmite calcite was confirmed by comparison to the date of cave void opening 14c analyses or by using dated event horizons measured stalagmite growth rate was determined from annual laminae thickness measurements and compared to that theoretically predicted from the chemical kinetics of the calcite precipitation reaction a good agreement is observed between empirical observations and theoretical predictions although two complicating factors variations in calcite porosity and seasonal cessation of the water supply to the samples both affect the growth rate implications for the extraction of palaeoclimate information from stalagmite growth rate are discussed

holocene variations in asian monsoon moisture a bidecadal sediment record from the south china sea the east asian monsoon system involves extensive transport of sensible latent heat between land and sea and from low to high latitudes our high resolution bidecadal marine records present a first detailed history of monsoon climate change over the holocene the high amplitude perturbation in monsoon moisture centered at 8 150 years ago and the monsoon maximum in the early holocene show inter hemispheric teleconnections to both a cool episode in greenland and to the indian monsoon monitored in the arabian sea periodicities of 84 102 and especially near 775 years in monsoon variation suggest a climatic forcing both by long term oscillations in thermohaline circulation and possibly solar activity cycles

east asian summer monsoon precipitation variations in china over the last 9500 years a comparison of pollen based reconstructions and model simulations to better understand the long term changes of the east asian summer monsoon precipitation p jja quantitative reconstructions and model simulations are needed here we develop continental scale pollen based transfer functions for p jja with weighted averaging partial least squares wa pls regression and a bayesian multinomial regression method we apply these transfer functions to a set of fossil pollen data from monsoonal china for quantitatively reconstructing the p jja changes over the last 9500 years we compare the reconstructions with p jja simulations from a coupled atmosphere ocean sea ice general circulation model the kiel climate model kcm the results of cross validation tests for the transfer functions show that both the wapls model r2 0 83 root mean square error of prediction rmsep 112 11 mm and the bayesian model r2 0 86 rmsep 107 67 mm exhibit good predictive performance we stack all p jja reconstructions from northern china to a summary curve the stacked record reveals that p jja increased since 9500 cal yr bp attained its highest level during the holocene summer monsoon maximum hsmm at similar to 7000 4000 cal yr bp and declined to present the kcm output and the reconstructions differ in the early holocene similar to 9500 7000 cal yr bp where the model suggests higher p jja than the reconstructions moreover during the hsmm the amplitude of the p jja changes similar to 20 60 mm above present in simulations is lower than the reconstructed changes similar to 70 110 mm above present the rising declining p jja patterns in reconstructions before after the hsmm are more pronounced and fluctuating than in simulations other palaeohydrological data such as lake level reconstructions indicate substantial monsoon precipitation changes throughout the holocene our results therefore show that the kcm underestimates the overall amplitude of the holocene monsoon precipitation changes

the hydrothermal system of the calabozos caldera central chilean andes abstract active thermal springs associated with the late pleistocene calabozos caldera complex occur in two groups the colorado group which issues along structures related to caldera collapse and resurgence and the puesto calabozos group a nearby cluster that is chemically distinct and probably unrelated to the colorado springs most of the colorado group can be related to a hypothetical parent water containing 400 ppm cl at 250 c by dilution with 50 of cold meteoric water the thermal springs in the most deeply eroded part of the caldera were derived from the same parent water by boiling the hydrothermal system has probably been active for at least as long as 300 000 years based on geologic evidence and calculations of paleo heat flow there is no evidence for economic mineralization at shallow depth the calabozos hydrothermal system would be an attractive geothermal prospect were its location not so remote

dissolved inorganic carbon isotope compositions of drip water in panlong cave southwest china high resolution carbon and oxygen isotope records in stalagmites provide significant information for quantitative paleo reconstructions of past temperature and precipitation this paper describes results of isotopic analysis of dissolved inorganic carbon dic in panlong cave water from drips and shallow pools cave water was sampled monthly throughout 2012 and analyzed for 13cdic composition the values of 13cdic in drip water were in the range of 10 42 to 16 07 while the values of 13cdic in pool water were in the range of 1 88 to 6 94 dissolved inorganic carbon isotope records showed a gradual stepwise negative excursion from january to august and a gradual stepwise positive excursion from september to december 13cdic in cave water showed remarkable seasonal variations which were negative excursion from 2 to 5 in rainy season than in dry season a negative 13cdic excursion in summer was not the result of vegetation types which was contributed to enhance root respiration and decomposition of soil organic matter a correlation between 13cdic values of perennial drip water and pool water samples with air temperature and precipitation amount suggests that these negative excursions were caused by increasing air temperature during rainy season negative excursions in 13cdic values of seasonal drip water were correlated with monthly precipitation caused by the influx of soil organic matter into the cave hence this paper provides an important framework and an empirical basis for reconstructing temperature from stalagmites and drip water in this region

a preliminary reconstruction of rainfall in north central china since a d 1600 from tree ring density and width abstract may june mj and april july aj precipitation at huashan in north central china has been reconstructed for the period a d 1600 to 1988 using tree ring density and width from pinus armandii mj precipitation based on ring width and maximum latewood density calibrated and cross validated against local instrumental data more strongly than aj precipitation based only on ring width a major drought was reconstructed for the mid and late 1920s confirmed by local documentary sources this drought culminating in 1929 was the most severe of the 389 yr period for mj and second most severe for aj after an event ending in 1683 neither reconstruction shows much spectral power at frequencies lower than 1 in 10 yr but both show concentrations of power between 2 1 and 2 7 yr and 3 5 to 9 yr there are significant correlations between the two reconstructions and a regional dryness wetness index dw based on documentary sources particularly at high frequencies these correlations are focused in the 7 6 to 7 3 3 8 to 3 6 and 2 5 yr periods using singular spectrum analysis quasiperiodic behavior with a period close to 7 2 yr was identified in the mj precipitation reconstruction and in the dw index based on documents

increased effective moisture in northern vietnam during the little ice age abstract we present a 650 yr record of hydroclimate inferred from 18o values of lacustrine carbonate from ao tien fairy pond in northern vietnam ao tien occupies a collapsed karst basin that formed during the worst drought of the last millennium i e the angkor i drought which marks a dry transitional period between the medieval climate anomaly and the little ice age a multi centennial trend of increasing effective moisture spans the little ice age ending with aridity in the late 18th century that accompanied great societal turmoil across southeast asia after 1850 ce the ao tien record exhibits a drying trend that continues to the present over the last 650 years the 18o inferred hydroclimate is significantly correlated with the reconstructed southern oscillation index of precipitation soipr suggesting that a prolonged la nina like state existed during the little ice age generating overall wetter conditions in vietnam decadal scale droughts and pluvials from the ao tien record agree with a robust tree ring hydroclimate reconstruction from southern vietnam that identified the angkor i and ii droughts of the late 13th early 14th centuries and significant droughts during the early and late 17th century and latter half of the 18th century the decrease in effective moisture during the last 30 years is also evident in the tree rings and is consistent with a documented weakening of the pacific walker circulation major pluvials are indicated for the period between the two angkor droughts and the wettest period of the record is during the early 18th century comparison of the ao tien data with records from indonesia to china indicates regionally coherent climate during the little ice age however the overall wet conditions in easterly sites are difficult to ascribe to shifts in the itcz rather the pattern suggests that pacific walker circulation may have been the overriding control on precipitation

oxygen and carbon isotope patterns archived in shells of the aquatic gastropod radix hydrologic and climatic signals across the tibetan plateau in sub monthly resolution abstract the tibetan plateau tp including its surrounding mountain ranges represents the largest store of ice outside the polar regions it hosts numerous lakes as well as the head waters of major asian rivers on which billions of people depend and it is particularly sensitive to climate change the moisture transport to the tp is controlled by the indian and pacific monsoon and the westerlies understanding the evolution of the interaction of these circulation systems requires studies on climate archives in different spatial and temporal contexts the objective of this study is to learn more about the interannual variability of precipitation patterns across the tp and how different hydrologic systems react to different climatic factors aragonite shells of the aquatic gastropod radix which is widely distributed in the region may represent suitable archives for inferring hydrologic and climatic signals in particularly high resolution therefore sclerochronological studies of 18 o and 13 c ratios in radix shells from seven lakes were conducted each representing a different hydrologic and climatic setting on a transect from the pamirs across the tp the shell patterns exhibit an increasing influence of precipitation and a decreasing influence of evaporation on the isotope compositions from west to east 18 o values of shells from lakes on the eastern and central tp donggi cona yamdrok yumco tarab co mirror monsoon signals indicated by more negative values and higher variabilities compared to the more western lakes karakul bangong nyak manasarovar in yadang co located on the central southern tp the monsoon rains did not reach the lake in the sampling year although it is located in a region which is usually affected by monsoon circulation the 18 o values are used to differentiate the annual hydrological cycle into ice cover period melt water period precipitation period and evaporation period 13 c compositions in the shells particularly depend on specific habitats which vary in biological productivity and in carbon sources 18 o and 13 c patterns show a positive covariance in shells originating from large closed basins the results show that radix shells mirror general climatic differences between the seven lake regions these differences reflect both regional and local climate signals in sub seasonal resolution without noticeable dependence on the particular lake system

summer monsoon precipitation variations in central china over the past 750 years derived from a high resolution absolute dated stalagmite abstract a 2 3 year resolution record of stalagmite oxygen isotope variations from the south flank of the qinling mountains central china has revealed the asian summer monsoon asm precipitation variations in the investigated area over the past 750 years the summer monsoon precipitation gradually increased since 1249 ad reaching its highest values in the period 1535 1685 ad and then decreased with substantial decadal to centennial scale fluctuations the monsoon precipitation increased again between 1920 and 1970 ad three intervals of high monsoon precipitation were identified 1535 1685 ad 1755 1835 ad and 1920 1970 ad three intervals of low precipitation were inferred in 1249 1325 ad 1390 1420 ad and 1890 1915 ad the 18 o composition and lithological features of the stalagmite coincidently indicate a wetter climate during the little ice age lia which is also confirmed by climate records from chinese historical documents within this area a comparison with other high resolution speleothem records indicates regional differences in monsoon precipitation variability from the south to the north of central china in the last 750 years on decadal to centennial scale power spectrum analysis of the 18 o record shows significant 117 8 34 6 14 10 3 and 6 year periodicities these periodicities are widely observed in the climate records from asm controlled areas of china and are consistent with the gleissburg periodicity br ckner periodicity sunspot periodicity of solar activity and el nino southern oscillation enso periodicity these correlations suggest that both solar activity and enso periodicity may have had important influences on asm precipitation in china over the past 750 years

east asian monsoon variability since the mid holocene recorded in a high resolution absolute dated aragonite speleothem from eastern china abstract paleoclimatic conditions associated with the east asian monsoon are reconstructed for the mid to late holocene using 18o values 819 measurements from a precisely dated 10 230th dates aragonite stalagmite from lianhua cave hunan province china 18o values 1 6 to 7 0 are interpreted to reflect the precipitation amount effect related to the strength of summer monsoonal circulation throughout this period the intensity of east asian summer monsoonal circulation declined in response to changes in insolation and a southward shift in the intertropical convergence zone itcz punctuating this first order trend are abrupt millennial to decadal scale fluctuations the most prominent of which occurred around 3337 5 yr bp and records a dramatic weakening in summer monsoonal circulation that coincides with the beginning of neoglacial conditions comparisons between the 18o values of stalagmite a1 and previously published data from stalagmite hs 4 from heshang cave and stalagmites d4 and da from dongge cave china demonstrate a similar regional response to changes in east asian monsoonal circulation several spectral analysis techniques and wavelet analysis were applied to these stalagmite records to evaluate the nature and character of cyclicity in the east asian monsoon during the holocene multi taper method mtm lomb scargle and single spectrum analysis ssa results reveal common periodicities that are unlikely to be artifacts of any single technique the periodicities expressed in the stalagmite 18o records occur at both solar and non solar frequencies and support previous interpretations that variability in monsoonal circulation responds to both solar forcing and internal climatic mechanisms wavelet analysis demonstrates that some of these frequencies are intermittent and recur at semi regular intervals which may indicate long term cyclicity that is unconstrained by the chronology of the record

high resolution absolute dated indian monsoon record between 53 and 36 ka from xiaobailong cave southwestern china the oxygen isotopic record of stalagmite xbl 1 from southwestern china reveals millennial scale variability of the indian monsoon between 53 and 36 ka synchronous with changes in the east asian monsoon recorded at hulu cave and similar to dansgaard oeschger cycles recorded in greenland ice our record in general confirms the chronology of hulu cave if our correlations between greenland and the xiaobailong cave record are correct both the greenland ice sheet project 2 and greenland ice core project ss09sea chronologies are accurate within quoted errors a dry interval that we correlate with heinrich event 5 h5 and the greenland stadial preceding greenland interstadial 12 gis 12 is centered ca 48 0 ka and a shift to drier conditions correlated to the end of gis 12 is ca 43 5 ka overall the variability of the indian monsoon from xbl 1 data on millennial scales is similar to and correlated with high latitude ice core rec ords from the northern hemisphere however some indian monsoon characteristics more closely resemble but are anticorrelated with features in the antarctic record suggesting some link to climate of the high southern latitudes in addition to the clear link to the climate of the high northern latitudes

reconstruction of the northeast asian monsoon climate history for the past 400 years based on textural carbon and oxygen isotope record of a stalagmite from yongcheon lava tube cave jeju island korea abstract paleoclimatic changes over the past 400 years were investigated based on textural and geochemical characteristics of the yc 2 stalagmite which grew in yongcheon cave lava tube cave on jeju island korea the stalagmite is about 68 mm long and annual growth laminae are distinctively identified the age of the stalagmite was mainly determined by counting annual growth laminae supplemented by other radiometric dating methods and it is estimated that the stalagmite grew at least for ca 242 years including the hiatus this hiatus is located at about 15 mm from the base and is present in the form of one thick brown growth lamina which was formed when the stalagmite stopped to grow texturally the stalagmite can be divided into two phases fluid inclusion poor compact columnar calcite phase a and fluid inclusion rich sparse columnar calcite phase b this textural division is intimately related to the spacing of growth laminae that is phase a is characterized by narrower spacing of growth laminae phase a with narrow spaced growth laminae indicates the slower growth rate due to lower amount of rainfall when northeast asian summer monsoon intensity was relatively lower based on high resolution carbon isotope trend the stalagmite can be divided into three stages stages i ii and iii the relatively more positive carbon isotopic compositions of the stage i 13 c 3 3 0 4 pdb in the lower part indicate that it grew during the little ice age lia under cold and dry climate with less vegetation the stage ii is a transitional period from cold and dry to warm and wet climate with a continuous decrease in carbon isotope values from 0 6 to 9 6 in 13 c this stage shows the gradual weakening of the lia climate carbon isotope trend also suggests that the lia interval was terminated near middle 1870 s around korean peninsula relatively low carbon isotopic compositions during stage iii 13 c 11 0 8 0 in the upper part should indicate that climate was changed to the warm and wet current warm period warming since 1960 can also be recognized complete coincidence between textural data internal calcite texture and growth laminae spacing and high resolution carbon isotope compositions strongly suggests that past climate changes such as monsoonal variations in northeast asia have been clearly recorded in the stalagmite in yongcheon cave

asynchronous holocene optimum of the east asian monsoon abstract the spatial and temporal distribution of summer monsoon precipitation or effective moisture during the holocene has been reconstructed on the basis of geological data including lake levels pollen profiles and loess paleosol records in addition the summer july precipitation increment effective precipitation and monsoon strength index have been obtained from numerical modeling experiments both geological data and numerical modeling indicate that the holocene optimum as defined by peak east asian summer monsoon precipitation was asynchronous in central and eastern china reaching a maximum at different times in different regions e g ca 10 000 8000 yr ago in northeastern china 10 000 7000 yr ago in north central and northern east central china ca 7000 5000 yr ago in the middle and lower reaches of the yangtze river and ca 3000 yr ago in southern china in southwestern china the maximum appeared ca 11 000 yr ago but probably was related to the maximum landward extension of the indian summer monsoon the regional shift in the maximum precipitation belt from northwest to southeast over the past 10 000 yr is interpreted as a response to changing seasonality related to orbital forcing of the climate the southeastward shift of the east asian summer monsoon maximum is consistent with the progressive weakening of the summer monsoon as the summer solar radiation anomaly decreased progressively through the holocene and the east asian monsoon index declined while the early maximum in southwestern china matches the maximum of the indian monsoon index

spatial variations of monsoonal rain in eastern china instrumental historic and speleothem records abstract we select four caves and their nearby cities in the monsoonal region of china for studying the relationships among precipitation temperature summer monsoon intensity and stalagmite 18o the instrumental historic and stalagmite 18o records from these areas show strong spatial disparities on annual to decadal scales so that climatic conditions in a single location cannot represent these of the entire eastern china on time scales

archaeology of the anthropocene in the yellow river region china 8000 2000 cal bp although archaeological analysis emphasizes the importance of climatic events as a driver of historical processes we use a variety of environmental and archaeological data to show that human modif

panigarh cave stalagmite evidence of climate change in the indian central himalaya since ad 1256 monsoon breaks and winter southern jet depressions abstract variations in petrography stable isotopes reflectance and luminescence along the central growth axis of a 14 5 cm stalagmite from panigarh cave indicate cooler and slightly wetter conditions in the himalayan foothills of northern india during the little ice age lia which lasted from ad 1489 1889 based on deposition of calcite and ad 1450 1820 based on rapid changes in 18o values conditions were warmer and drier during the preceding medieval climate anomaly mca and also in the post lia periods as evidenced by deposition of aragonite a review of currently existing stalagmite and other proxy data from south and east asia reveals a broad spatial pattern in precipitation over south and east asia during the lia with northern areas showing generally increased precipitation and southern areas reduced precipitation during the mca and after the lia the records suggest this pattern was reversed weaker ism during the lia brought drought conditions to the core ism area but triggered more monsoon breaks that brought higher precipitation to the himalayas at the same time the weaker ism may also have pushed more depressions along the path of the southern winter jet which brought more winter precipitation to the himalayas and therefore a lia wetter in our study area

centennial to decadal scale monsoon precipitation variations in the upper hanjiang river region china over the past 6650 years abstract the upper hanjiang river region is the recharge area of the middle route of south to north water transfer project the region is under construction of the hanjiang weihe river water transfer project in china monsoon precipitation variations in this region are critical to water resource and security of china in this study high resolution monsoon precipitation variations were reconstructed in the upper hanjiang river region over the past 6650 years from 18 o and 13 c records of four stalagmites in xianglong cave the long term increasing trend of stalagmite 18 o record since the middle holocene is consistent with other speleothem records from monsoonal china this trend follows the gradually decreasing northern hemisphere summer insolation which indicates that solar insolation may control the orbital scale east asian summer monsoon easm variations despite the declined easm intensity since the middle holocene local precipitation may not have decreased remarkably as revealed by the 13 c records a series of centennial to decadal scale cyclicity was observed with quasi millennium quasi century 57 36 and 22 year cycles by removing the long term trend of stalagmite 18 o record increased monsoon precipitation during periods of 4390 3800 a bp 3590 2960 a bp 2050 1670 a bp and 1110 790 a bp had caused four super floods in the upper reach of hanjiang river dramatically dry climate existed in this region during the 5 0 ka and 2 8 ka events coinciding with notable droughts in other regions of monsoonal china remarkably intensified and southward westerly jet together with weakened summer monsoon may delay the onset of rainy seasons resulting in synchronous decreasing of monsoon precipitation in china during the two events during the 4 2 ka event and the little ice age the upper hanjiang river region was wet which was similar to the climate conditions in central and southern china but was the opposite of drought observed in northern china we propose that weakened summer monsoon and less strengthened or normal westerly jet may cause rain belt stay longer in the southward region which reduced rainfall in northern china but enhanced it in central and southern china

replicated stalagmite inferred centennial to decadal scale monsoon precipitation variability in southwest china since the mid holocene a lack of agreement between stalagmite records of the centennial to decadal scale asian summer monsoon asm variability since the mid holocene limited our understanding of forcings and the possible impacts on culture evolution here we present replicated high resolution stalagmite 18o profiles from dark cave in guizhou province southwest china established with 512 oxygen isotope data and 28 230th ages providing a continuous history of the asm precipitation from 6100 to 300 years before present yr bp before ad 1950 consistency of stalagmite 18o inferred long term decreasing asm trends since the mid holocene between caves at this site and others in the indian and east asian monsoon realms on orbital timescales supports the effect of primary orbital solar forcings on monsoonal precipitation the dark cave records display significant centennial to decadal scale variations more evident than previous stalagmite records spectral analysis of the dark cave 18o time series yields periodicities of 731

oxygen 18 16 variability in greenland snow and ice with 10 3 to 105 year time resolution the 3 km long greenland ice sheet project 2 gisp2 ice core presents a 100 000 year detailed oxygen isotope profile covering almost a full glacial interglacial cycle measuranents of isotopic fluctuations in snow frost and atmospheric water vapor samples collected during summer field seasons up to 20 0 are compatible with the large and abrupt 80 160 changes observed in accumulated tim snow pit 15 80 profiles from the gisp2 summit area however show rapid smoothing of the 180 160 signal near the surface beyond about 2 m depth the smoothedi5180 signal is fairly well preserved and can be interpreted in terms of average local weather conditions and climate the longer climate fluctuations also have regional and often global significance in the older part of the record corresponding to marine isotope stages mis 5a to 5d the effect of orbital climate forcing via the 19 and 23 kyr precession cycles and the 41 kyr obliquity cycle is obvious from the end ofmis 5a at about 75 000 years b p till the end of the glacial at the younger dryas preboreal transition at 11 650 years b p the o180 160 record shows frequent rapid switches between intermediate interstadial and low stadial values fourier spectra of the oscillations that are superimposed on the orbitally induced changes contain a strong periodicity at 1 5 kyr a broad peak at 4 0 kyr and additional shorter periods detailed comparison of the gisp2 180 160 record with the vostok antarctica 15d record pacific ocean foraminiferal 180 160 grande pile france tree pollen and insolation indicates that a counterpart to many of the rapid 180 160 fluctuations of gisp2 can be found in the other records and that the gisp2 isotopic changes clearly are the local expression of climate changes of worldwide extent correlation of events on the independent gisp2 and specmap time scales for the interval 10 000 50 000 years b p shows excellent chronometric agreement except possibly for the event labeled 3 1 the glacial to interglacial transition evidently started simultaneously in the arctic and the antarctic but its development and its expression in greenland isotopes was later suppressed by the influence of meltwater especially from the barents sea ice sheet on deep water formation and ocean circulation meltwaters from different ice sheets bordering the north atlantic also influenced ocean circulation during the bolling allerod interstadial complex and the younger dryas and led to a distinct development of european climate and greenland 180 160 values the holocene interval with long term stable mean isotopic values contains several fluauations with periods from years to millennia dominant is a 6 3 year oscillation with amplitude up to 3 to 4 0 periodicities of 11 and 210 years also found in the solar modulated records of the cosmogenic isotopes 1obe and 14c suggest solar processes as the cause of these cycles depression of180 160 values cooling by volcanic eruptions is observed in stacked gisp215 80 records but the effect is small and not likely to trigger major climate changes

palaeo climate reconstruction from stable isotope variations in speleothems a review abstract speleothems are now regarded as valuable archives of climatic conditions on the continents offering a number of advantages relative to other continental climate proxy recorders such as lake sediments and peat cores they are ideal materials for precise u series dating yielding ages in calendar years thereby circumventing the radiocarbon calibration problems associated with most other continental records stable isotope studies in speleothems have shifted away from attempting to provide palaeo temperature reconstructions to the attainable goal of providing precise estimates for the timing and duration of major o isotope defined climatic events characterised by high signal to noise ratios e g glacial interglacial transitions dansgaard oeschger oscillations the 8200 year event unlike the marine records speleothem data sets are not tuned and their independent chronology offers opportunities to critically assess leads and lags in the climate system that in turn can provide important insights into forcing and feedback mechanisms improved procedures for the extraction and measurement of stable isotope ratios in fluid inclusions trapped in speleothems are likely to provide in the near future a much enhanced basis for the quantitative interpretation of o isotope ratios in speleothem calcite the latter developments open up once again the tantalising prospect of palaeo temperature estimates but more importantly perhaps provide a direct test for a new generation of general circulation models whose hydrological cycles will incorporate the water isotopes the literature is reviewed briefly to provide for the reader a sense of the current state of the art and to provide some pointers for future research directions

climate significance of speleothem δ18o from central china on decadal timescale abstract speleothem based oxygen isotopic sequences have been widely used to reveal regional climatic changes worldwide however the climatic significance of speleothem 18o variations in monsoonal china on decadal to annual timescales remains in debate which limits its application to paleoclimate reconstruction in the world s largest country by population in this study we analyzed a seasonally resolved 18o record of an annually layered stalagmite xl21 whose variability covers a period of 98 years 1912 2009 ad from xianglong cave central china the annual 18o trend shows an inverse relationship with local monsoon precipitation suggesting speleothem 18o variations in this area can reflect monsoon precipitation at least on decadal timescale changes in moisture sources and transport pathways have little effect on the 18o variations in speleothems monsoon precipitation on decadal timescale which may be ascribed to similar distances from this region to the two main moisture sources the bay of bengal and west pacific there is an anti phase relationship between speleothem 18o records from central china and india during the last 98 years which indicates the relationship between indian monsoon intensity and speleothem 18o from central china on short timescales requires further investigation

folding in high grade rocks due to back rotation between shear zones abstract folds with a sense of asymmetry opposite to the bulk shear sense may form in high grade rocks due to back rotation between ductile shear zones layers back rotated into the shortening field can undergo additional buckle folding with progressive deformation shear zones and domains of back rotated foliation between shears rotate towards the x y flattening plane of the finite strain ellipsoid in high grade gneiss the migration of melt into shear zones may facilitate displacement along them and accentuate back rotation of material between shear zones folding during back rotation occurs when the spacing between shear zones does not increase sufficiently to accommodate the length of back rotated layers or between non parallel shear zones folds formed by back rotation between shear zones commonly have pegmatites sub parallel to their axial planes thickened overturned limbs and occur in localised packages associated shear zones have the same sense of shear on both attenuated limbs of folds formed by back rotation examples are given for folds between transcurrent and normal ductile shear zones in the albany mobile belt and leeuwin complex western australia and the dharwar craton india

general characteristics of temperature variation in china during the last two millennia three alternate china wide temperature composites covering the last 2000 years were established by combining multiple paleoclimate proxy records obtained from ice cores tree rings lake sediments and historical documents five periods of temperature variation can be identified a warm stage in ad 0 240 a cold interval between ad 240 and 800 a return to warm conditions from ad 800 1400 including the medieval warm period between ad 800 1100 the cool little ice age period between 1400 1920 and the present warm stage since 1920 regional temperature variation is found during ad 800 1100 when warm conditions occurred in eastern china and in the northeastern tibetan plateau and in ad 1150 1380 when the southern tibetan plateau experienced a warm interval in contrast evidence for cool conditions during the lia is more consistent among the proxy records the temperature reconstructions for china and the northern hemisphere show good agreement over the past millennium

a high resolution absolute dated late pleistocene monsoon record from hulu cave china oxygen isotope records of five stalagmites from hulu cave near nanjing bear a remarkable resemblance to oxygen isotope records from greenland ice cores suggesting that east asian monsoon intensity changed in concert with greenland temperature between 11 000 and 75 000 years before the present yr b p between 11 000 and 30 000 yr b p the timing of changes in the monsoon as established with 230th dates generally agrees with the timing of temperature changes from the greenland ice sheet project two gisp2 core which supports gisp2 s chronology in this interval our record links north atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer east asian monsoon originates

a high resolution absolute dated holocene and deglacial asian monsoon record from dongge cave china abstract we present a continuous record of the asian monsoon over the last 16 ka from 18o measurements of stalagmite calcite over 900 oxygen isotopic measurements providing information on shifts in monsoon precipitation are combined with a chronology from 45 precise 230th dates 18o and therefore asian monsoon intensity generally follows changes in insolation although changes in 18o are generally accommodated in abrupt shifts in contrast to smoothly varying insolation indicating that threshold effects may be important 18o decreased dramatically 3 at the start of the holocene 11 5 ka and remained low for 6 ka four positive 18o events centered at 11225 97 yr bp 1 05 10880 117 yr bp 1 15 9165 75 yr bp 1 4 and a double event centered at 8260 64 yr bp 1 1 and 8080 74 yr bp 1 0 punctuated this period of high monsoon intensity all four events correlate within error with climate changes in greenland ice cores thus the relationship between the asian monsoon and the north atlantic observed during the glacial period appears to continue into the early holocene in addition three of the four events correlate within error with outburst events from lake agassiz the decline of monsoon intensity in the mid late holocene is characterized by an abrupt positive shift in 18o which occurs at 3550 59 yr bp 1 1 in 100 yr in addition the holocene is punctuated by numerous centennial and multi decadal scale events amplitudes 0 5 to 1 up to half the amplitude of the glacial interstadial events seen in the last glacial period thus holocene centennial and multi decadal scale monsoon variability is significant although not as large as glacial millennial scale variability the monsoon shows a strong connection with northern south american hydrological changes related by changes in itcz position spectral analysis of the 18o record shows significant peaks at solar periodicities of 208 yr and 86 yr suggesting variation is influenced by solar forcing however there are numerous other significant peaks including peaks at el nino frequencies observed for high resolution portions of the record between 8110 and 8250 yr which suggest that changes in oceanic and atmospheric circulation patterns in addition to those forced by solar changes are important in controlling holocene monsoon climate in addition for this high resolution portion we observe a distinctive biennial oscillation of the asian monsoon which has been associated with the tropospheric biennial oscillation tbo

climate variability in central china over the last 1270 years revealed by high resolution stalagmite records oxygen and carbon isotopic variations in the upper section of a stalagmite sf 1 from buddha cave 33 40 n 109 05 e dated by 230th 234u 210pb and lamination counting to a time resolution as fine as 1 3 years have recorded climate changes in central china for the last 1270 years the changes include those corresponding to the medieval warm period little ice age and 20th century warming lending support to the global extent of these events the isotopic records also show cycles of 33 22 11 9 6 and 7 2 years the 33 year cycle could well represent the 35 year periodicity of climate fluctuations previously recognized in china and europe cycles of 22 11 and 9 6 years have often been associated with the sunspot or lunar orbit variations the 7 2 year cycle was recently identified also in tree ring records from an area close to buddha cave these cycles suggest that external forcing e g solar irradiance may affect the summer monsoon over eastern china the general consistency between the climate characteristics inferred from the stable isotope records of sf 1 and those from other proxy records underscores the value of stalagmites as recorders of paleoclimate