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Spatial differences of rainfall in monsoonal China during the last glacial period remain contentious. Here, we present new 230Th-dated stalagmite records (δ13C and δ18O) from central China (the Yangtze River valley), spanning approximately 75–10 ka BP, to address this issue. We interpret the stalagmite δ13C variations primarily as indicators of regional rainfall changes, which show significantly decreased rainfall during MIS 4 and late MIS 3 to MIS 2. On the millennial timescale, the δ13C record indicates decreased rainfall during Heinrich (H) events and increased rainfall during Dansgaard-Oeschger interstadials. The strong correlations between our δ13C record and the westerly proxies suggest that the westerly jet played a crucial role in influencing rainfall patterns in monsoonal China throughout the last glacial period. We propose that rainfall changes in central China were consistent with northern China on both orbital and millennial timescales during the last glacial period. This observation contrasts with the modern rainfall differences between northern and central China. Our results imply that with a colder climate in high northern latitudes, the rain belt over monsoonal China influenced by the westerly jet shifted further south beyond the Yangtze River Valley during MIS 4, late MIS 3 to MIS 2 and H events, leading to a consistent decrease in rainfall over central and northern China. In contrast to the rainfall records, the stalagmite δ18O values were more negative during late MIS 3. The δ18O variations on the orbital timescale are likely related to the changes in the tropical ocean conditions controlled by insolation, which determines the δ18O values in evaporated moisture before its transport into the Asian continent. On the millennial timescale, our δ13C and δ18O records exhibit coupled variations, implying that the stalagmite δ18O variations are consistent with the rainfall changes in central and northern China. • New stalagmite δ13C and δ18O records spanning the last glacial period (75–10 ka BP) from central China. • Consistent rainfall changes in central and northern China on both orbital and millennial timescales. • Coupled variations between δ13C and δ18O records on the millennial timescale. [ABSTRACT FROM AUTHOR]

Abstract: One‐year‐resolved and annually‐counted stalagmite multi‐proxies (δ18O, δ13C, and layer width) from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon (ASM) and local humidity across Bond events (BE) in the Preboreal. During BEs 8 and 7, 1.5± enrichments in δ18O values were generally consistent with high‐ to low‐latitude climate changes. In detail, the decadal‐scale minor δ18O oscillations in BE8 were broadly less than the mean value, in contrast to the significant changes in local soil moisture derived from the δ13C values and layer records. In the mid‐BE7, δ18O variability was generally above the average level, and higher‐ amplitude variations were observed in the three proxy indicators. Wavelet analysis on the total δ18O time series and across the specific time windows of BEs 8 and 7 identified periodicities of about 130, 60, and 20‐a, respectively. Exceptionally strong in BE7, the 60‐a cycle, pervasively observed in instrumental studies, became prominent starting at 11.4 kaBP. Thus, glacial background conditions are important for suppressing the ASM intensity in BE8, while during BE7, tropical hydrological circulations were potentially actively involved. Consequently, climate internal oscillations, analogous to modern conditions, might have occurred in the distant past once the link between the tropical ocean and atmosphere was established as occurs today. [ABSTRACT FROM AUTHOR]

Both external forcing and internal climate variability are playing significant roles in driving the East Asian summer monsoon (EASM) changes. However, dynamic linkages between these natural forcings and EASM on decadal timescales remain uncertain, partly due to the limited instrumental climate data. Here, we present a high-resolution EASM record over the past 200 years based on 2315 δ18O measurements from two annually laminated stalagmites (YX92 and YX120) in Yongxing Cave over the middle Yangtze River Valley (mid-YRV). Our records match well with the δ18O records from the nearby Heshang Cave, showing that EASM intensity in the mid-YRV varies at a dominant periodicity of ∼80 years. The multidecadal-scale oscillations in the EASM intensity are closely related to the ENSO-like states, supporting a notion that the ENSO dominantly modulates the EASM variability. Furthermore, the decadal oscillations in EASM and ENSO are synchronous with tropical volcanic eruptions during the solar minima, probably leading to the enhanced El Niño-like response, intensified EASM and strengthened ENSO-EASM coupling. Our findings imply that external forcings potentially contribute to the anomalies in ENSO and EASM during the ongoing global warming. • EASM changes at a dominant periodicity of ∼80 years over the past 200 years. • Multidecadal-scale oscillations in EASM intensity closely related to ENSO-like states. • Decadal oscillations in EASM and ENSO evolution synchronous with tropical volcanic eruptions during the solar minima. • Tropical volcanic eruptions likely enhanced the ENSO-EASM coupling. [ABSTRACT FROM AUTHOR]

Two annually-laminated and 230 Th-dated stalagmite oxygen isotope (δ 18 O) records from Dongge Cave, China, provided a high-resolution Asian Summer Monsoon (ASM) history for the past 1200 years. A close similarity between annual band thickness and stable isotope analyses (δ 13 C and δ 18 O) suggests the calcite δ 18 O is most likely a proxy associated with ASM precipitation. The two duplicated stalagmite δ 18 O records show that the ASM varies at a periodicity of ∼220 years, concordant with a dominant cycle of solar activity. A period of strong ASM activity occurred during the Spörer Minimum (1450–1550 A.D.), followed by a striking drop circa 1580 A.D., potentially consistent with the social unrest in the final decades of China's Ming Dynasty (1368–1644 A.D.). Centennial-scale changes in ASM precipitation over the last millennium match well with changes in tropical Atlantic sea surface temperatures (SSTs) and South American summer monsoon precipitation. Our findings suggest that variations in low-latitude monsoon precipitation are probably driven by shifts in the mean position of the intertropical convergence zone (ITCZ), which is further mediated by solar activity and tropical SSTs. [ABSTRACT FROM AUTHOR]

Meteorological observations indicate that both natural and anthropogenic forcing contribute to regional drought/flood in the East Asian summer monsoon (EASM) domain. However, spatiotemporal rainfall pattern and its dynamics during natural climatic variability remains unclear. Here we reconstruct a ∼3 year-resolution EASM precipitation record over the past two millennia, based on 13 230Th dates and 600 δ18O in a stalagmite from Songya Cave, southeastern China. The δ18O sequence shows a long-term decreasing trend, indicating an increasing monsoon precipitation over the past two millennia. A series of centennial-scale fluctuations are superimposed on the long-term trend, with a wetter Little Ice Age than the Medieval Warm Period. The long-term trend and centennial-scale oscillations in EASM rainfall are broadly related to El Niño-Southern Oscillation (ENSO) and Pacific decadal oscillation (PDO) variations, with an increased (decreased) EASM rainfall corresponding to El Niño-like (La Niña-like) conditions and positive (negative) phase of PDO. Comparison of δ18O records from Songya and Wanxiang Cave shows an anti-phased spatial rainfall pattern between southeastern and northwestern China. This spatiotemporal rainfall pattern, consistent with the modern observations, is possibly regulated by the ENSO, through changes in the location and strength of the Western Pacific Subtropical High (WPSH). • A long-term increasing monsoon precipitation in southeastern China over the past two millennia. • An anti-phased "southeastern-northwestern" rainfall pattern in the monsoonal China. • The spatiotemporal pattern of EASM precipitation modulated by ENSO and PDO. [ABSTRACT FROM AUTHOR]

An anti-phased relationship between Greenland Dansgaard-Oeschger (DO) and Antarctic temperature was revealed by ice core records, and the "bipolar see-saw" mechanism has since been proposed in explanation for the interhemispheric thermal redistribution. However, limited by chronology uncertainties of ice cores, particularly the ice age-gas age differences, the exact phase relationship and triggers for millennial-scale events are still in debate. Searching for proxies that could reflect both boreal and austral signals in one geological archive is therefore, a potential solution for the phase dilemma. Here, high-resolution paleoclimatic records from 55.2 to 36.5 ka BP were reconstructed using 21 230Th/U dates and 647 sets of δ18O and δ13C data by one stalagmite HJ1 from Huangjin Cave, Hebei Province, northern China. Robust millennial-scale fluctuations are found in δ18O and δ13C time series, corresponding to DO events 8 to 14 and Heinrich 4 and 5 events within dating errors. Discrepancies exist in the structures and onsets in δ18O and δ13C records; that is, abrupt DO onsets in δ13C data and gradual onsets in δ18O. Timing of DO onsets in δ13C are prior to (e.g. DO12 and DO14) or synchronous with (e.g. DO8 to DO11) those in δ18O. Comparison of HJ1 δ18O and bipolar ice core records suggests that the East Asian summer monsoon (EASM) is influenced by both hemispheres, but better mimics the Antarctic temperature. This suggests that the EASM is controlled by the cross equatorial airflows, and further indicates an important role of the Atlantic Meridional Overturning Circulation (AMOC) in modulating the inter-hemispheric heat gradient. However, our δ13C profile strongly resembles with the Greenland δ18O record on the millennial timescale, in terms of the "sawtooth" structure and the abrupt transition. This indicates that northern high-latitude climate could modulate hydro-thermal conditions in northern China, possibly via the mid-latitude westerly jet and/or the Silk Road teleconnection, which influences the vegetation/biomass changes and thereby controls stalagmite δ13C values. Therefore, HJ1 δ18O receives climatic signals from the Southern Hemisphere (SH) to a larger extent, while δ13C captures largely the changes in the Northern Hemisphere (NH). Furthermore, comparison between calcite and ice core records shows that during DO14, temperature increases in the NH leads the SH cooling by ∼120 years. However, during short-term DO events, the SH may start cooling ∼150 years before the NH warming. These findings demonstrate two possibilities for the NH-SH phase relationship which are dependent on the trigger location of the AMOC recovery and the "bipolar see-saw" mode is likely controlled by the oceanic processes. • Greenland-type sawtooth structure is found in stalagmite δ13C in northern China. • Hydrothermal condition in northern China linked to the northern high-latitude via westerly jet. • Antarctica -type triangle shape revealed in Chinese stalagmite δ18O. • Two types of Greenland-Antarctica phase relationship depend on the trigger location. [ABSTRACT FROM AUTHOR]

Abstract: High-resolution oxygen isotope records of three stalagmites from Sanbao (central China), Wulu (southern China) and Dashibao (southern China) Caves, based on 876 oxygen isotope measurements and 25 precise 230Th dates, provide a detailed Asian monsoon (AM) history from 32.5 to 20.8kaB.P., spanning the shift between Marine Isotope Stages 3 and 2. The calcite δ18O records, although geographically widespread (about 1000km between them), including the previously-reported Hulu record, are similar in timing, shape, and amplitude. These observations support the idea that changes in speleothem δ18O largely represent variations of precipitation isotopic composition associated with large-scale summer monsoon circulation over a large portion of China. These profiles show four centennial to millennial scale strong summer monsoon events, analogous in timing and structure to Greenland Interstadials 5 through 3 (GIS 5–3). Chronology of the events refines the Hulu record and broadly supports the NGRIP GICC05 timescale. Five weak monsoon events are identified at 31.2, 30.1, 28.1, 25.7 and 24.2kaB.P., all of which correspond to stadial events in Greenland. The 30.1 and 24.2ka events correlate with Heinrich stadials 3 and 2. Furthermore, these events correlate to warm episodes in Antarctic ice cores, indicating that the climatic response to North Atlantic cooling is similar in China and in Antarctica, but in an opposite sense. These observations are consistent with the bi-polar seesaw hypothesis. The strong coupling between AM circulation and climate at both high latitudes at the centennial scale indicates that atmospheric circulation changes are important in transmitting abrupt climate signals globally. [ABSTRACT FROM AUTHOR]

• A composite high-resolution monsoon precipitation record over the mid-YRV. • Centennial-scale oscillations in EASM rainfall related to solar activity and ENSO. • An anti-phase relationship of monsoon rainfall between the mid-YRV and tropical WNP. • A new EAP index calculated as the difference between monsoon rainfall in the mid-YRV and WNP. • A strong correlation between the EAP and SOI index. Meteorological observations reveal an inverse relationship of summer monsoon rainfall between the tropical western North Pacific (WNP) and middle Yangtze River Valley (mid-YRV) on interannual and intraseasonal timescales. This seesaw-like pattern, named the East Asian-Pacific (EAP) pattern, is one of the major teleconnections that affect summer precipitation in the mid-YRV. However, due to the scarcity of long and continuous instrumental data, the behavior and mechanism of the EAP pattern on a long timescale are poorly understood. Here, we present a composite high-resolution summer monsoon rainfall record from 230 BC to 1810 AD, based on 1221 δ 18 O measurements and 22 230Th dates from two stalagmites (EB1 and EB5) in Shenqi Cave over the mid-YRV. Our new record shows that monsoon rainfall in the mid-YRV varies at a dominant periodicity of ∼100 years, probably linked to solar activity and ENSO variability. The multi-centennial fluctuations in the EB record, broadly consistent with the North Hemisphere temperature reconstruction, display strong similarities to two stalagmite δ 18 O records from nearby Heshang and Luoshui caves. To represent the integrated hydroclimate variations over the mid-YRV, we extracted the first principal component (PC1) of these three cave δ 18 O records by using the principal component analysis. We reveal a striking inverse relationship of wet/dry conditions between the mid-YRV and tropical WNP, suggesting that changes in the EAP pattern have an important impact on centennial-scale monsoon precipitation changes. Furthermore, we compile monsoon rainfall records from the mid-YRV and WNP to reconstruct a new EAP index. This EAP index exhibits a strong correlation with the ENSO proxy, confirming that the ENSO variability may play a key role in modulating the monsoon rainfall in the mid-YRV through the EAP teleconnection. [ABSTRACT FROM AUTHOR]

We reconstructed high-resolution paleoclimate records with 24 230Th/U dates, 706 sets of stable isotope values (δ18O and δ13C) from a stalagmite from Shima Cave, Hunan Province, central China. The stalagmite grew during the last deglaciation from 19.7 to 13.3 ka, with a 1500-year hiatus during Heinrich Stadial 1. We interpret stalagmite δ18O as the East Asian summer monsoon (EASM) intensity, while δ13C as terrestrial CO 2 related with biomass production and local hydrogeochemical processes. Long-term trend and millennial-scale changes in δ18O record are absent in the δ13C record, possibly due to the low biomass production and small vegetation changes in central China across the studied period, which is contrast to an obvious recovery of the biomass in northern China during the Bølling-Allerød period. Besides, high frequency of δ13C record displays quasi periods of 30–50 years, which are consistent with typical periodicities of the Pacific Decadal Oscillation (PDO). Furthermore, comparison of our δ18O record with measures of solar variability shows clear evidence for solar forcing on the EASM on the centennial timescale, which could possibly be mediated by the Atlantic Meridional Overturning Circulation and El Niño/Southern Oscillation/PDO. Therefore, we suggest that monsoonal climate and ecological changes during the last deglaciation could have been modulated by solar activity and sea surface temperature variability in both the Atlantic and the Pacific Ocean. [ABSTRACT FROM AUTHOR]

Stalagmite oxygen isotope (δ18O) records have enhanced our understanding of the history of the East Asian monsoon. However, abrupt changes in the monsoon are not constrained well enough to address certain issues and there are still unknowns in the interpretation of cave δ18O records. Here we present a new high-resolution stalagmite record from Shima Cave, central China. Anchored with 24 230Th/U dates, our sample grew from 19.7 to 17.8 ka and from 16.3 to 13.3 ka, covering much of the early portion of the last deglaciation with a temporal resolution of 7 years. Using this record and other available Asian δ18O records, we test model predictions for shifts in δ18O in Asian caves and further investigate monsoon variations on centennial to decadal timescales during the early portion of the last termination. We conclude the following regarding the interpretation of δ18O in Chinese caves. Two mechanisms affect δ18O: changes in the fraction of monsoon rainfall in annual totals (the Wang-Cheng mechanism) and changes in the amount of rainout between tropical sources and cave sites (the Yuan mechanism). The former is caused by changes in the seasonal migration of the sub-tropical jet and likely has a smaller effect on cave δ18O than the latter. The latter involves changes in rainout from both the Pacific and the Indian Ocean sources. Precisely how that change in rainout is partitioned between sources and cave sites is not fully understood; however, it is clear that some of the change takes place in China; i.e. it is not restricted to upstream sites. Rough calculations for our site suggest that mean annual rainfall may have been two-thirds of modern values at the time of the highest δ18O values during Heinrich Stadial 1 (HS1) (16.1 ka) and one fifth again higher than modern values during the Bølling (14.3 ka). Within HS1, consistent with observations from other localities, Chinese cave records exhibit a twofold structure. Within the phases, we observe a truly remarkable relationship between the North Atlantic ice rafted debris record and the Hulu-Shima Cave record, where events ranging from multi-centennial to sub-decadal timescale can be related across Eurasia. The origin of this two-phased structure may relate to different sources and extent of ice-rafted debris in the North Atlantic as well as the extent of sea ice and the Atlantic Meridional Overturning Circulation. • Two mechanisms affect Chinese stalagmite δ18O: the Wang-Cheng mechanism and the Yuan mechanism. • A two-phased structure of East Asian Monsoon during Heinrich Stadial 1, an early weakening and a subsequent weaker condition. • A remarkable relationship between ice-rafting events and weak monsoon events on the multi-centennial to sub-decadal scale. [ABSTRACT FROM AUTHOR]

Stable isotope data of precipitation (δ18Op and deuterium excess), drip water (δ18Od), and modern calcite precipitates (δ18Oc and δ13Cc) from Yongxing Cave, central China, are presented, with monthly sampling intervals from June 2013 to September 2016. Moderate correlations between the monthly variation of δ18Op values (from − 11.5 to − 0.7‰) and precipitation amount (r = − 0.59, n = 34, p < 0.01) and deuterium excess (r = 0.39, n = 31, p < 0.01) imply a combined effect of changes in precipitation amount and atmospheric circulation. At five drip sites, the δ18Od values have a much smaller variability (from − 9.1 to − 7.5‰), without seasonal signals, probably a consequence of the mixing in the karst reservoir with a deep aquifer. The mean δ18Od value (− 8.4‰) for all drip waters is significantly more negative than the mean δ18Op value (− 6.9‰) weighted by precipitation amount, but close to the wet season (May to September) mean value (− 8.3‰), suggesting that a threshold of precipitation amount must be exceeded to provide recharge. Calculation based on the equilibrium fractionation factor indicates that the δ18Oc values are not in isotopic equilibrium with their corresponding drip waters, with a range of disequilibrium effects from 0.4 to 1.4‰. The δ18Oc and δ13Cc values generally increase progressively away from the locus of precipitation on glass plates. The disequilibrium effects in the cave are likely caused by progressive calcite precipitation and CO2 degassing related to a high gradient of CO2 concentration between drip waters and cave air. Our study provides an important reference to interpret δ18Oc records from the monsoon region of China. [ABSTRACT FROM AUTHOR]

In this study, a 140 kyr stack (MT2022) of 95 stalagmite δ18O records from Southern China was synthesized using the error weighted mean method and the linear weighted mean method. This stack record was derived from approximately 1100 U/Th dating and 40000 δ18O data points. On orbital scale, MT2022 agrees with the variation of the summer (21 July) insolation at 65°N and restores as much detail as possible of the actual variability of Asian Summer Monsoon (ASM) from stalagmite records. The age model of MT2022 was established according to the dating results of each sample record, and the start and end periods of each weak monsoon event were constrained by at least five stalagmite sample records, with average errors of less than 0.2 kyr. By comparison, we find that MT2022 was generally consistent with the Speleothem Interstadial Onset Compilation data set (SIOC19) and had more sample records from the ASM domain, which is more suitable to represent the ASM evolution. Furthermore, comparing MT2022 to three Greenland ice core timescales, we discovered that MT2022 was quite consistent with NGRIP (GICC05) over the last 60 kyr and differed from GRIP (ss09sea) and GISP2 (Meese-Sowers). The main discrepancy between MT2022 and GRIP occurs around Dansgaard-Oeschger (DO) events 14 and 20–23, whereas MT2022 and GISP2 start to deviate prominently beyond 40 kyr BP. The high degree of consistency between GICC05 and MT2022 allows their accuracy to be validated against each other, thus, MT2022 may provide a new chronological reference for climatic events in the last glacial-interglacial cycle as well as an age calibration standard for other palaeoclimate archives. [ABSTRACT FROM AUTHOR]

The pattern and cause of middle-to late-Holocene hydroclimatic variability in central-west China remain unclear. We present a new pair of stalagmite isotopic (δ18O and δ13C) records and trace element ratio (Mg/Ca, Ba/Ca, and Sr/Ca) records from Jinfo Cave, central-west China. We established a uranium-series chronology that shows that the stalagmite grew between 5.6 and 0.6 kyr BP. The similarities between our δ18O stalagmite record and other published records suggest that δ18O generally reflects overall monsoon intensity or rained-out effect between the cave site and moisture source, but not necessarily regional rainfall amount. Corresponding changes in Mg/Ca, Ba/Ca, Sr/Ca, and δ13C are mostly dependent on local factors, such as the nature of the ecosystem above the cave, water-rock interactions, and the prior calcite precipitation effect. As the δ13C records bear a remarkable resemblance to Mg/Ca, Ba/Ca, and Sr/Ca records, we extracted the first principal component (PC1) of the four records and identified the PC1 as a regional hydroclimate proxy. The bandpass filter and cross wavelet transformation results show that the ∼500 years periodicity of PC1 exhibits in-phase oscillations with solar activity and the El Niño-Southern Oscillation (ENSO) throughout the middle to late Holocene, suggesting that changes in solar activity influence centennial hydroclimate variation and are amplified by ENSO. Another prominent feature seen in PC1 is a progressive positive shift from 3.0 kyr BP, which indicates that central-west China moved toward a drier climate over this period. We attribute this climate transition to a strengthening El Niño event and its impact on oceanic and atmospheric anomalies. • The first principal component of stalagmite δ13C and trace elemental ratios is interpreted as a hydroclimate proxy. • Centennial "sun-climate" connection is amplified by the ENSO. • A climatic shift from wet to dry can be identified since 3.0 ka BP. • The "3kyr shift" results from a strengthening of El Niño. [ABSTRACT FROM AUTHOR]

The Heinrich Stadial 2 (HS2) event is poorly defined in the Greenland δ18O ice core record; however, it can be identified in stalagmite records from China. In this paper, we reconstruct an absolutely-dated and high-resolution calcite δ18O record from Shima Cave, central China, covering the interval from 26.0 to 23.9 ka BP, with a temporal resolution of ~16 years. By integrating our newly reported record with all available δ18O records of Marine Isotope Stage 2 from China, which are securely 230Th/U-dated, we calculate the timing of the onset, termination and duration of HS2. The statistical results show that the prominent HS2a phase started at ~24.4 ± 0.1 ka BP and ended at ~23.6 ± 0.1 ka BP, lasting approximately 0.8 ± 0.3 ka. If the onset of the Dansgaard-Oeschger 2 event in the Greenland δ18O record is synchronous with the termination of HS2a, then the GICC05 chronology should be adjusted by +230 years to align it with stalagmite results. Further investigation of HS2 shows that Chinese cave records exhibit a distinct two-fold structure, corresponding to HS2a and HS2b, as observed in marine sediment cores, particularly those recovered around the Atlantic Ocean. These records show comparable changes in relative amplitudes during the HS2a and HS2b phases, which could possibly be related to different weakening episodes in the Atlantic Meridional Overturning Circulation. • An ~16-year-resolution East Asian summer monsoon (EASM) history covering the onset of Heinrich Stadial 2 event. • Statistical analyses of timing for Heinrich Stadial 2. • Globally pervasive twofold structure during Heinrich Stadial 2. [ABSTRACT FROM AUTHOR]

Our knowledge about climatic changes at centennial-scale and their causes during the Holocene climatic optimum (HCO) remains poorly constrained. Here, we present δ18O and δ13C records from a precisely dated stalagmite (13.2 to 1.9 kyr BP) from Xiniu Cave, central China. The δ18O record shows a gradual weakening in the strength of the East Asian summer monsoon (EASM) from early to middle Holocene, corresponding with a decrease in Northern Hemisphere summer insolation (NHSI). A similar pattern is absent in our δ13C record, and is replaced by persistent centennial-scale oscillations throughout the Holocene. Variations of δ13C reflect changes in vegetation density, soil CO 2 production, CO 2 degassing, prior calcite precipitation (PCP), and cave ventilation, associated with temperature and rainfall variations at local scale. Based on the δ13C record, three dry/cold events at approximately 6.0, 8.2, and 10.5 kyr BP, can be identified during the HCO (11.1 ± 0.1 to 5.4 ± 0.1 kyr BP), coinciding with the well-known Holocene Bond events. The power spectrum analysis shows that the significant periodicity (843 yr) of the δ13C record within the HCO may be related to the North Atlantic-cycle. Therefore, we speculate that the centennial-scale climatic changes during the HCO probably resulted from cooling in the North Atlantic, and that the intensified and southward Westerly jet played a role in transmitting this signal from high latitudes to central China. • Stalagmite records from central China spanning last deglaciation to Holocene. • Variations of stalagmite δ13C are controlled by both rainfall and temperature. • The timing of the HCO can be identified more clearly by using a new tool. • Centennial-scale climatic events in the HCO resonate with North Atlantic climate. [ABSTRACT FROM AUTHOR]

Marine Oxygen Isotope Stage 12 (MIS 12), the last glacial period before the Mid-Brunhes event (MBE), is considered the coldest glacial period during the past several glacial/interglacial cycles and is important because it can help better understand the cyclicity and mechanism of the millennial-scale variability of a glacial period. However, owing to the lack of precisely dated and high-temporal-resolution records, the millennial-scale variability during this period remains unclear. A 230Th/U dated stalagmite from Luoshui Cave, Hubei Province, Central China, was analyzed for stable oxygen isotopes (δ18O). An ∼120-yr-resolution δ18O profile is presented to clarify the Asian summer monsoon (ASM) history between 464 and 420.6 kyr BP (Before present, where present = 1950 CE), which corresponds to the interval from the MIS 12 to the early part of the MIS 11. The MIS 12 monsoon generally followed the insolation differences on June 21 between 30°N and 30°S and was interrupted by ten Chinese interstadial events (CISs). At least nine prominent weak monsoon intervals (WMIs) were identified during MIS 12 and displayed a strong coupling with the northern high-latitude climate and Antarctic temperature through the bipolar seesaw model, suggesting a substantial relationship with the bipolar region. This indicates that millennial-scale variability in the ASM region is an inherent feature of the MBE and has a global teleconnection. Additionally, in contrast to the EPICA DOME C3 (EDC 3) timescale, the new absolutely dated speleothem record confirms the Antarctic Ice Core Chronology 2012 (AICC 2012) at MIS 12, a period with a large difference between the two ice record geochronologies over the past 800 kyr. • A high resolution and precision dating stalagmite record was presented to clarify the ASM history of MIS 12 in China. • The new record over the MIS 12 follows orbitally induced insolation variations and is interrupted by thirteen CISs and nine WMIs on the millennial-scale. • The CISs are consistent to the variation of Mid-high North Atlantic environment. • The WMIs over MIS12 presented anti-phased relationship with Antarctic temperature. • This research confirms that the millennial scale climate variation before the MBE is a continuous feature. [ABSTRACT FROM AUTHOR]

Multi-proxy analysis of abrupt climate change during Ice Age Termination III (T-III) is necessary to understand Asian summer monsoon (ASM) characteristics and mechanisms. We present 230Th dates and δ 18O, δ 13C, with equilibrium diameter, carbonate deposition amount and lithological characteristics from an annually laminated stalagmite (No. YXB) in Yongxing Cave, central China. Our multi-proxy records span 243.90 to 239.20 ka before present, falling within T-III/Marine Isotope Stage 7e. The changes in δ 18O, equilibrium diameter, carbonate deposition amount, and lithological characteristics suggest a weak ASM interval during T III. By comparing these results with records from Ice Age Termination I (T-I), we find that the weakened ASM event during T-III is similar to the Younger Dryas (YD) event in terms of duration and structure. This result suggests that the YD-like event could be an inherent feature of glacial-interglacial climate cycles in the middle and late Pleistocene. The YXB δ 13C sequence, without YD-like events, is broadly similar to the δ 18O record on orbital timescale, indicating that variations in local vegetation could be driven by rising CO 2 during ice age terminations. • Stalagmite records based on layer counting chronology from Southern China. • Stalagmite δ 18O, lithological characteristics indicate a weak Asian summer monsoon interval during Termination III. • Duration and structure of weak monsoon interval during Termination III is similar to Younger Dryas. • δ 13C indicates no YD-III but driven by greenhouse gases during ice age terminations. [ABSTRACT FROM AUTHOR]

The relationship between monsoon circulation and regional hydrology in the Yangtze River Basin since the Last Glacial Maximum (LGM) remains unclear. In this study, we present speleothem (LS46) δ18O and δ13C records over the past 23.5 kyr from the Luoshui Cave in Central China. Stalagmite LS46 δ13C displayed a good similarity with variations in δD wax -derived monsoon precipitation from Lake TengchongQinghai (TCQH) and the extreme precipitation events identified by the IRM soft-flux from Heshang Cave, thus indicating that speleothem calcite δ13C reflects the changes in regional hydrology. The ensemble empirical mode decomposition (EEMD) and wavelet spectrum analyses revealed that the regional hydrology was paced by ∼2000-year periodicity during the LGM and last deglaciation and ∼ 1000-year periodicity during the Holocene, respectively. Our results further indicated that the El Niño-Southern Oscillation (ENSO) plays an important role in regulating changes in the frequency and magnitude of regional hydrology in the Yangtze River Basin under different climatic conditions. Moreover, our results demonstrated that δ18O and δ13C were coupled on multiple timescales, thus potentially indicating that local hydrological variations in the middle reaches of the Yangtze River are regulated by large-scale monsoonal circulation. However, we also found that the δ18O and δ13C profiles decoupled during the last deglaciation, likely due to a decrease in evapotranspiration in combination with a decrease in monsoon intensity and temperature during this period. Consequently, the regional hydrological conditions did not experience any dramatic changes. • The relationship between monsoon circulation and regional hydrology was explored. • We interpreted that stalagmite δ13C reflects changes in regional hydrology. • The hydrology exhibited a period of ∼2000 yr from the LGM to the deglaciation and ∼1000 yr during the Holocene. • We made calculations for the precipitation integrated during the Hs1, YD, and HCO relative to the past 2 kyr. • We found that the δ18O and δ13C coupled on multiple scales, but missing in last deglaciation. [ABSTRACT FROM AUTHOR]

Climate reconstructions over the last millennium are essential to estimate natural and anthropogenic forcing. Here we present a stalagmite δ18O record from southwestern China, which characterizes changes in the Asian Summer Monsoon (ASM) precipitation over the past 1350 years. Wet climate is clearly identified during the Dark Age Cold Period (DACP) and Little Ice Age (LIA); dry climate is clearly identified during the Medieval Warm Period (MWP) and Current Warm Period (CWP). These precipitation oscillations, except that over the CWP, are remarkably similar to, but strongly antiphase with, those in northwestern China. Over the CWP, our δ18O record, similar to other stalagmite records in East Asia, also exhibits a gradually increasing trend. This trend has been assumed to be caused by anthropogenic temperature warming. Here a better correlation is identified between our record and atmospheric temperature change during the preindustrial and industrial eras. This correlation provides solid evidence for the consistent modulation of the temperature on the ASM precipitation without and with the human-induced forcing. However, this modulation may act in a different manner during the industrial era, which results in the same δ18O variation across East Asia. In sum, our record provides a clear spatial variation of the ASM precipitation and highlights persistent temperature modulation on the ASM without and with anthropogenic emissions. • A new stalagmite record clearly shows a wet DACP and LIA, but dry MWP and CWP in southern China. • Precipitation variations in southern China are antiphase with those in northern China on the multi-centennial scale. • Precipitation in southern China changed in step with atmospheric temperature throughout the last millennium. [ABSTRACT FROM AUTHOR]

A continuous high-resolution record from a precisely-dated stalagmite spanning the last precessional cycle provides new insight into the dynamics of climate change from orbital to centennial scales. A 600-mm length stalagmite (LS46) collected from the Luoshui Cave, Hubei Province, Central China, was well-dated (a total of 24 230Th dates) and high-resolved sampled for oxygen and carbon stable isotopic measurements (2047 subsamples in total). The stalagmite LS46 δ18O is consistent with other published stalagmite δ18O time series in monsoonal China, and closely tracks changes in the Northern Hemisphere summer insolation (NHSI) on July 21st throughout the past 23.5 kyr. Besides, the stalagmite LS46 δ18O shows significant correlations with the reconstructed Dali lake-level history and tree-ring δ18O records in the marginal monsoon regions. On this basis, we interpret that the stalagmite LS46 δ18O reflects the large-scale monsoon circulation with a superimposed local climate signal that might be related to effective humidity. Furthermore, the stalagmite LS46 δ18O exhibited four long-lasting extremely weak monsoon events since 7 kyr B.P.. These four weak monsoon events corresponded well with the tree-ring record in the northwestern fringe of the East Asian summer monsoon (EASM) region. Notably, the good correspondence between the stalagmite record and the tree-ring record also provides a good chronological support for our assessment of the climate and cultural evolution during the middle-late Holocene transition, the medieval warm period (MWP) and Little Ice Age (LIA). During the early-middle Holocene, the detrended δ18O profile revealed 10 multi-centennial monsoon cycles with a duration of nearly 500 yr and the amplitude of ∼0.8‰. The wavelet analysis further discloses that the EASM has nearly 500 yr and 200 yr periodic oscillations in the early-middle Holocene, research indicated that the solar activity and the North Atlantic Oscillation (NAO)/North Atlantic Deep Water (NADW) jointly drive the dominant nearly 500 yr cycle of the Asian monsoon. • A successive stalagmite δ18O/δ13C series from Central China over the past 23.5 kyr. • Stalagmite δ18O coincides with tree ring δ18O and lake level. • LS46 δ18O records 4 weak monsoon events since 7 kyr B.P. and corresponds well to the tree ring data in NW China. • ∼500 yr periodicity of AM during the Early-Mid Holocene was forced by solar activity and the NAO. [ABSTRACT FROM AUTHOR]

There continues to be debate on the wet and dry conditions in central China due to different geological archives and proxy interpretations. This study reconstructed multi-proxy sequences spanning intervals between 65 and 40 ka using high-precision Th-230 dates, which was carried out on a stalagmite from Yongxing cave in the middle Yangtze Valley located in the Meiyu belt, China. Merely according to the petrography of the sample, Heinrich (H) 5-H6, Dansgaard–Oeschger (DO) 9-DO18 (or even secondary changes including DO15a and DO15b; DO17a, DO17b, and DO17c) were directly identified alongside the oxygen isotope record. The δ13C, trace elements, mineralogical, and bio-geochemical proxies exhibited similar millennial changes to that of the δ18O. This provided an indication of responses to millennial-scale climatic events in the karst hydrological cycle, local environment, and soil vegetation; however, the sensitivities to these events differed. Petrographic analyses of the same stalagmite including scanning electrical microscope (SEM), X-ray diffraction (XRD), fluorescence intensity, the deposition rate, and the diameter index depicted a dry-cold climate during the H events, and a wet-warm climate during the DO cycles in the middle Yangtze Valley. These results are consistent with the peat records of Dajiuhu Lake in the same area. We suggest that a combination of Atlantic Meridional Overturning Circulation (AMOC) and El Niño-Southern Oscillation (ENSO) may exert a strong influence on the Meiyu region and the related precipitation. • Identification of H events and DO cycles through stalagmite's petrography. • The δ13C and trace elements have similar trend and different amplitude to that of δ18O. • Petrographic analysis (i.e. SEM, grey-level, etc.) show a humid climate in DO cycles. • Sedimentary features such as laminae morphology exhibit a dry climate in H events. • The coupling effect of AMOC and ENSO affect the climate in the Meiyu region. [ABSTRACT FROM AUTHOR]

Abstract: Although the initiation and continuation of orbital and millennial climate transitions were reported to be roughly similar, little is yet known about the extent to which their sequences of climate events are linked together in the same physical processes. Here we present a stalagmite isotope record from Wulu Cave, southwestern China, based on 1200 oxygen isotope data and 15 230Th ages, registering a detailed history of the Asian Monsoon (AM) from 61.3 to 50.5 ka BP with an average resolution of 12 yr. Two replicated, high-resolution calcite δ18O profiles show four millennial-scale strong summer monsoon events, analogous in timing and structure to Chinese Interstadials A.17–A.14 (CIS A.17–A.14), as recorded elsewhere in China and Greenland Interstadials 17–14 (GIS 17–14). These events exhibit two distinct phases, consistent with multi-decadal/centennial shifts in Greenland temperature and storminess. This relationship reveals a tight coupling between high- and low-latitude climates at sub-millennial scales, implying a role for westerly winds in linking Greenland temperature and the AM. Around the Marine Isotope Stage (MIS) 4/3 boundary, successive AM events resemble, but in higher frequency, structure of the Bølling–Younger Dryas (YD) surrounding Termination I. Along with evidence from similar shifts in bipolar temperature and atmospheric CH4, we suggest that the recurrence of similar climate structure worldwide is likely caused by changes in Atlantic meridional overturning circulation (AMOC) at various timescales under thresholds of global ice volume boundaries, as predicted by the bipolar seesaw model. [Copyright &y& Elsevier]