{"title":"Multi‐Proxy Evidence for Atlantic Meridional Overturning Circulation (AMOC) Weakening During Deglaciations of the Past 150,000 Years","authors":"Monica Garity, David Lund","doi":"10.1029/2023pa004629","DOIUrl":"https://doi.org/10.1029/2023pa004629","url":null,"abstract":"Despite decades of research, the cause of deglaciations is not fully understood, leaving a critical gap in our understanding of Earth's climate system. During the most recent deglaciation (Termination I (T I)), abrupt declines in the stable carbon isotope ratio (δ13C) of benthic foraminifera occurred throughout the mid‐depth (1,500–2,500 m) Atlantic. The spatial pattern in δ13C anomalies was likely due to Atlantic Meridional Overturning Circulation (AMOC) weakening and the accumulation of respired carbon, which also yields negative excursions in carbonate ion concentration (). To investigate whether a similar pattern occurred during prior deglaciations, we developed δ13C and records from 1,800 and 2,300 m water depth in the Southwest Atlantic spanning the last 150 ka. The new records reveal negative δ13C and anomalies during Termination II (TII) and the smaller deglaciations of Marine Isotope Stages (MIS) 4/3, 5b/a, and 5d/c, suggesting AMOC weakening is a common feature of deglaciation. The anomalies are more pronounced in the shallower core following MIS 2, 4, and 6 and in the deeper core following MIS 5b and 5d. The depth‐dependent pattern is most likely due to shoaling of Northern Source Water during glacial maxima and deepening during interglacial intervals. Comparison of records from TI and TII suggests similar levels of carbon accumulation in the mid‐depth Atlantic. The Brazil Margin δ13C and results indicate the AMOC plays a key role in the series of events causing deglaciation, regardless of differences in orbital configuration, ice volume, and mean global temperature.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"94 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139538278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. P. Acosta, N. Burls, M. Pound, C. Bradshaw, A. D. de Boer, N. Herold, M. Huber, X. Liu, Y. Donnadieu, A. Farnsworth, A. Frigola, D. Lunt, A. S. von der Heydt, D. Hutchinson, G. Knorr, G. Lohmann, A. Marzocchi, M. Prange, A. Sarr, X. Li, Z. Zhang
{"title":"A Model‐Data Comparison of the Hydrological Response to Miocene Warmth: Leveraging the MioMIP1 Opportunistic Multi‐Model Ensemble","authors":"R. P. Acosta, N. Burls, M. Pound, C. Bradshaw, A. D. de Boer, N. Herold, M. Huber, X. Liu, Y. Donnadieu, A. Farnsworth, A. Frigola, D. Lunt, A. S. von der Heydt, D. Hutchinson, G. Knorr, G. Lohmann, A. Marzocchi, M. Prange, A. Sarr, X. Li, Z. Zhang","doi":"10.1029/2023pa004726","DOIUrl":"https://doi.org/10.1029/2023pa004726","url":null,"abstract":"The Miocene (23.03–5.33 Ma) is recognized as a period with close to modern‐day paleogeography, yet a much warmer climate. With large uncertainties in future hydroclimate projections, Miocene conditions illustrate a potential future analog for the Earth system. A recent opportunistic Miocene Model Intercomparison Project 1 (MioMIP1) focused on synthesizing published Miocene climate simulations and comparing them with available temperature reconstructions. Here, we build on this effort by analyzing the hydrological cycle response to Miocene forcings across early‐to‐middle (E2MMIO; 20.03–11.6 Ma) and middle‐to‐late Miocene (M2LMIO; 11.5–5.33 Ma) simulations with CO2 concentrations ranging from 200 to 850 ppm and providing a model‐data comparison against available precipitation reconstructions. We find global precipitation increases by ∼2.1 and 2.3% per degree of warming for E2MMIO and M2LMIO simulations, respectively. Models generally agree on a wetter than modern‐day tropics; mid and high‐latitude, however, do not agree on the sign of subtropical precipitation changes with warming. Global monsoon analysis suggests most monsoon regions, except the North American Monsoon, experience higher precipitation rates under warmer conditions. Model‐data comparison shows that mean annual precipitation is underestimated by the models regardless of CO2 concentration, particularly in the mid‐ to high‐latitudes. This suggests that the models may not be (a) resolving key processes driving the hydrological cycle response to Miocene boundary conditions and/or (b) other boundary conditions or processes not considered here are critical to reproducing Miocene hydroclimate. This study highlights the challenges in modeling and reconstructing the Miocene hydrological cycle and serves as a baseline for future coordinated MioMIP efforts.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139142406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Milankovitch Record From Middle Jurassic Platform Supports Moderate Coolhouse Glaciation","authors":"A. Husinec, J. Read","doi":"10.1029/2023PA004680","DOIUrl":"https://doi.org/10.1029/2023PA004680","url":null,"abstract":"There are few documentations of far‐field effects of coolhouse glaciation and its signature preserved within Middle Jurassic carbonate platforms. Through outcrop logging and time series analysis we document the cyclostratigraphy of the upper Bajocian‐Bathonian interval of the Adriatic Platform, Croatia. The 200 m thick, ∼3.3 Myr duration cyclic platform record consists of peritidal carbonate parasequences (n = 109) with high‐energy grainstone‐rudstone bases fining up into micritic carbonate caps. There is little evidence of long‐term exposure near purported sequence boundaries, indicating the succession is conformable above the parasequence scale. Time series were constructed using Dunham rank and stratigraphic position, and parasequence thickness and stratigraphic position. A statistical estimation of accumulation rates using average spectral misfit (ASM) and correlation coefficient (COCO) methods that compare spectral peaks with an astronomical model at various sedimentation rates suggests that these rates ranged from 4.5 to 6 cm/kyr, which is compatible with long‐term rates based on thickness divided by duration. The time series analysis of rank series and cycle thickness series indicates long‐term obliquity modulation (∼1 Myr), short obliquity modulation (173 kyr), strong obliquity, and weak precession. The 173 kyr cycle is particularly evident in the cycle thickness series. The similarity of the spectra to the obliquity‐dominated Cenozoic coolhouse supports moderate southern hemisphere glaciation driving glacioeustatic sea level changes during the Middle Jurassic.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139202648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Mitsunaga, R. Lupien, Samantha Ouertani, Brandon Stubbs, A. Deino, J. Kingston, M. Stockhecke, Erik T. Brown, James M. Russell
{"title":"High‐Latitude, Indian Ocean, and Orbital Influences on Eastern African Hydroclimate Across the Plio‐Pleistocene Boundary","authors":"B. Mitsunaga, R. Lupien, Samantha Ouertani, Brandon Stubbs, A. Deino, J. Kingston, M. Stockhecke, Erik T. Brown, James M. Russell","doi":"10.1029/2023PA004671","DOIUrl":"https://doi.org/10.1029/2023PA004671","url":null,"abstract":"Terrestrial‐marine dust fluxes, pedogenic carbonate δ13C values, and various paleovegetation proxies suggest that Africa experienced gradual cooling and drying across the Pliocene‐Pleistocene (Plio‐Pleistocene) boundary (2.58 million years ago [Ma]). However, the timing, magnitude, resolution, and relative influences of orbitally‐driven changes in high latitude glaciations and low latitude insolation differ by region and proxy. To disentangle these forcings and investigate equatorial eastern African climate across the Plio‐Pleistocene boundary, we generated a high‐resolution (∼3,000‐year) data set of compound‐specific n‐alkane leaf wax δ2H values—a robust proxy for atmospheric circulation and precipitation amount—from the HSPDP‐BTB13‐1A core, which spans a ∼3.3–2.6 Ma sequence in the Baringo‐Tugen Hills‐Barsemoi Basin of central Kenya. In combination with the physical sedimentology, our data indicate that precipitation varied strongly with orbital obliquity, not precession, during the late Pliocene, perhaps imparted by variations in the cross‐equatorial insolation gradient. We also observe a marked shift toward wetter conditions beginning ∼3 Ma that corresponds with global cooling, drying in western Australia, and a steepening of the west‐east zonal Indian Ocean (IO) sea surface temperature (SST) gradient. We propose that northward migration of the Subtropical Front reduced Agulhas current leakage, warming the western IO and causing changes in the IO zonal SST gradient at 3 Ma, a process that has been observed in the latest Pleistocene‐Holocene but not over longer timescales. Thus, the late Cenozoic moisture history of eastern Africa is driven by a complex mixture of low‐latitude insolation, the IO SST gradient, and teleconnections to distal high‐latitude cooling.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"6 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139204466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Tarique, W. Rahaman, N. Lathika, P. Prabhat, M. Thamban, Sambuddha Misra
{"title":"Enhanced CO2 Degassing From the Tropical Indian Ocean During Cold Climatic Events of the Last Glacial Cycle","authors":"M. Tarique, W. Rahaman, N. Lathika, P. Prabhat, M. Thamban, Sambuddha Misra","doi":"10.1029/2022PA004570","DOIUrl":"https://doi.org/10.1029/2022PA004570","url":null,"abstract":"Atmospheric CO2 variability on the glacial–interglacial (G–IG) timescale reflects a balance between oceanic and terrestrial processes involving carbon uptake and release. The Southern Ocean CO2 uptake is considered as an important modulator for the G–IG atmospheric CO2 variability, while the role of tropical ocean ventilation remains enigmatic. We present critical evidence for CO2 ventilation from the tropical Indian Ocean through the reconstruction of the Arabian Sea‐surface pCO2 for the past ∼136 ka utilizing boron isotope (δ11B) record of planktic foraminifera, Globigerinoides ruber. Our site in the Arabian Sea presently acts as a significant source of CO2. The reconstructed ΔpCO2 (ΔpCO2 = pCO2 Seawater − pCO2 Atmosphere) record shows an enhanced CO2 degassing up to ∼50 ppm during the major cooling events, such as the Last Glacial Maximum, Younger Dryas, and Heinrich‐Stadials. Our investigation based on multiproxy records of sea‐surface temperature, salinity, and productivity suggests that the northward invasion and shoaling of southern source CO2‐rich water, coupled with stronger upwelling, resulted in CO2 degassing during these cold intervals. This finding is in align with the tropical Atlantic which also demonstrated an enhanced CO2 degassing during the cold intervals; however, most of the upwelled CO2 was consumed as the water moved away from the upwelling sites. Therefore, our finding, when considered alongside tropical Atlantic records, suggests that tropical oceans played a minor role in reducing atmospheric CO2 levels during the cold intervals of the last glacial cycle, supporting the prevailing hypothesis.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139211437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Luminescence Chronology of Reticulated Laterites in the Humid Subtropical Mountains of South China","authors":"Jianhui Jin, Junjie Qiu, Z. Ling, Junjie Wei, Xinxin Zuo, Zhizhong Li, Chenyang Hou, Daiyu Xu","doi":"10.1029/2022PA004603","DOIUrl":"https://doi.org/10.1029/2022PA004603","url":null,"abstract":"Laterite is a red weathering crust developed with various rocks and Quaternary loose sediments as its parent material in the tropics and subtropics regions of the world. Since the 1930s, researchers have believed that the fluvial reticulated laterite in southern China was influenced by the warm and humid climate of the Middle Pleistocene. In recent years, the remains of Paleolithic human activities are often found in the reticulated laterite of southern China. However, the study of laterite chronology is sporadic or there is no critical chronological analysis, which causes uncertainty in the identification and discussion of the ages of reticulated laterite and Paleolithic sites. In this study, a Paleolithic site found in fluvial reticulated laterite in South China was systematically tested by quartz optical luminescence dating and geomorphic process analysis. The results show that, (a) The T3 terrace, an archive of hominin activity in the study area, primarily formed between 56 and 11 ka. (b) Reticulated laterite cannot be used simply to determine the ages of the Paleolithic sites found in this stratum, and typical reticulated laterite cannot be used as a marker for climatic stratigraphy and chronostratigraphy. The fluvial reticulated laterite in the southern tropics, under suitable hydrothermal conditions, can form within tens of thousands of years or even within 10 ka. (c) Human activities can affect the burial age of reticulated laterite, and the stratigraphic diachronism of riverine terraces can also lead to an inversion in the age of reticulated laterite.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"99 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139302284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luisa Wöstehoff, Arne Kappenberg, E. Lehndorff, Bernd Wagner, Konstantinos Panagiotopoulos, W. Amelung
{"title":"An Upper Pleistocene and Holocene Black Carbon‐Related Fire Record From the SW Balkans","authors":"Luisa Wöstehoff, Arne Kappenberg, E. Lehndorff, Bernd Wagner, Konstantinos Panagiotopoulos, W. Amelung","doi":"10.1029/2022PA004579","DOIUrl":"https://doi.org/10.1029/2022PA004579","url":null,"abstract":"Lake sediments are unique archives of human environment interactions. Lake Prespa is one of the oldest lakes in Europe, lying in the southwestern Balkans and thus on a possible dispersal route of anatomically modern humans from Africa. In this study, we investigated the effects of climate, vegetation and human activity on fire over the last 92,000 years in this region. Sediment samples were taken from Lake Prespa, and nearby Lake Ohrid for comparison of the regional relevance, and analyzed for benzene polycarboxylic acids as markers for burned organic carbon residues (black carbon, BC). Peaking contents of BC (up to 1 g BC kg−1 sediment) coincided with warm and humid phases, when forests expanded at marine isotope stages (MIS) 5 and 1. During the colder and more arid climates of MIS 4 and 2, BC contents were lowered by a factor of 10, with a distinct minimum during the Last Glacial Maximum (0.07 g BC kg−1). The ratio of pentacarboxylic acid to mellitic acid (B5CA/B6CA) declined from 1.2 at MIS 5 to values of 0.3 at MIS 2, confirming a change in fire regime. Overall, BC contents peaked at cycles of solar radiation, vegetation composition and fuel availability, and thus correspond to the BC signal of other environmental archives. However, in the Late Holocene and as a result of human sedentary settlement, BC production increased, independent of decreasing insolation forcing.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139305218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. H. H. Bom, K. G. D. Kochhann, U. Heimhofer, M. A. L. Mota, R. M. Guerra, M. G. Simões, G. Krahl, V. Meirelles, D. Ceolin, F. Fürsich, F. H. O. Lima, G. Fauth, M. Assine
{"title":"Fossil‐Bearing Concretions of the Araripe Basin Accumulated During Oceanic Anoxic Event 1b","authors":"M. H. H. Bom, K. G. D. Kochhann, U. Heimhofer, M. A. L. Mota, R. M. Guerra, M. G. Simões, G. Krahl, V. Meirelles, D. Ceolin, F. Fürsich, F. H. O. Lima, G. Fauth, M. Assine","doi":"10.1029/2023PA004736","DOIUrl":"https://doi.org/10.1029/2023PA004736","url":null,"abstract":"Fossils from the Araripe Basin (northeastern Brazil) are known for their remarkable preservation of vertebrates and invertebrates, even including soft tissues. They occur in carbonate concretions within organic carbon‐rich strata assigned to the Romualdo Formation. Here we present integrated stable isotope, elemental and microfossil records from the Sítio Sobradinho outcrop, Araripe Basin, northeastern Brazil. Our results imply that black shales hosting fossil‐bearing carbonate concretions within the lower Romualdo Formation were deposited during Oceanic Anoxic Event (OAE) 1b (Kilian sub‐event). Our high‐resolution multi‐proxy approach allows identifying four phases of environmental evolution. After a pre‐event phase, an early phase (onset of the negative carbon isotope excursion—nCIE) of water column stratification and reduced oxygenation likely preconditioned the system for organic carbon burial and preservation. A second phase (peak nCIE) was characterized by an intensified hydrological cycle and continental runoff, as well as increased influx of terrestrial organic matter. High input of continent‐derived nutrients might have enhanced biological productivity in the epicontinental sea, ultimately leading to increased organic carbon fluxes and burial, as well as carbonate dissolution at the seafloor. All together, these paleoenvironmental conditions resulted in expansion of an oxygen minimum zone (OMZ), favoring taphonomic processes that led to the excellent preservation of diverse macro‐ and microfossils. The nCIE recovery phase was characterized by reduced nutrient supply and organic carbon burial. Organic carbon sequestration in such paleoenvironments likely contributed to the recovery (increase) of stable carbon isotope (δ13C) records in the deep ocean during the Kilian sub‐event of OAE 1b.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139295694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Inoue, A. Fukushima, M. Chihara, A. Genda, M. Ikehara, T. Okai, H. Kawahata, F. Siringan, A. Suzuki
{"title":"Natural and Anthropogenic Climate Variability Signals in a 237‐Year‐Long Coral Record From the Philippines","authors":"M. Inoue, A. Fukushima, M. Chihara, A. Genda, M. Ikehara, T. Okai, H. Kawahata, F. Siringan, A. Suzuki","doi":"10.1029/2022PA004540","DOIUrl":"https://doi.org/10.1029/2022PA004540","url":null,"abstract":"Both proxy and model studies conducted to understand anthropogenic warming have revealed historical variations in sea‐surface temperature (SST) since the industrial revolution. However, because of discrepancies between observations and models in the late nineteenth century, the timing and degree of anthropogenic warming remain unclear. In this study, we reconstructed a 237‐year‐long record of SST and salinity using a coral core collected from Bicol, southern Luzon, Philippines, which is located at the northern edge of the western Pacific warm pool. The SST record showed volcanic cooling after several volcanic eruptions, including the 1815 Tambora eruption, but the pattern of change differed. Decadal SST variations at Bicol are connected to Pacific Decadal Variability (PDV). Therefore, it is suggested that the PDV conditions at the time of the eruption may have influenced marine conditions, such as the degree and duration of cooling and/or salinity, after the eruptions. Although there were discrepancies in SST variations among the modeled, observed, and proxy SST data from the late nineteenth to early twentieth centuries, SST data from the late twentieth century showed globally coherent anthropogenic warming, especially after 1976. In particular, summer SST in the northwestern Pacific has become more sensitive to anthropogenic forcing since 1976.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"261 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139291261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Precipitation Oxygen Isotope Changes Over East Asia Driven by Sea Surface Conditions During the Last Glacial Maximum","authors":"Haimao Lan, Kei Yoshimura, Zhongfang Liu","doi":"10.1029/2023PA004692","DOIUrl":"https://doi.org/10.1029/2023PA004692","url":null,"abstract":"The seasonal changes in East Asian monsoon precipitation during the Last Glacial Maximum (LGM, 23,000–19,000 years B.P.) and its isotopic expression remain ambiguous. This study investigates changes in the seasonal precipitation δ18O (δ18Op) over East Asia during the LGM relative to the preindustrial (PI) and the underlying mechanisms using an isotope‐enabled atmospheric general circulation model. We show more depleted δ18Op in summer and a meridional tripolar δ18Op pattern in winter during the LGM compared to the PI. The depletion of summer δ18Op resulted from stronger upstream convective rainout due to the intensification of the Intertropical Convergence Zone. In contrast, the mechanisms for winter δ18Op changes were more complicated. With a series of sensitivity tests, we demonstrate that sea surface temperature controlled δ18Op changes across the whole of East Asia in summer and in the southern part of East Asia in winter. The depletion of winter δ18Op in central China arose largely from the suppression of droplet evaporation due to higher snow fraction. Our work provides important insights into the aspect of seasonal isotope changes during the LGM and may help facilitate an improved level of paleoclimatic interpretation of speleothem δ18O records from East Asia.","PeriodicalId":506796,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":"192 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139299662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}