The bright band (BB), a critical zone where solid precipitation transforms into liquid precipitation, plays a significant role in radar quantitative precipitation estimation (QPE) and drop size distribution (DSD) analysis. Existing studies of the BB have been mainly conducted in low and middle altitude areas, while studies in extremely high lands are still insufficient. This study systematically investigates the bright band characteristics in the Nam Co (4718 m above sea level) area on the Tibetan Plateau (TP) through integrated analysis of X-band dual-polarization radar and Micro Rain Radar (MRR) data, focusing on four aspects: optimization of the BB identification methods, geometric characteristics, polarimetric characteristics, and convective features embedded within the BB. The dual-polarization vertical profile reflectivity (dPVPR) BB identification algorithm was optimized and applied to analyze the BB characteristics of 14 precipitation cases in 2024. The results reveal that the BB in Nam Co area exhibits distinct characteristics: compared to low-altitude areas, it occurs at a lower height above ground level (253 to 614 m), and its thickness ranging from 448 to 774 m. Moreover, this study found that Lake Nam Co significantly influences the BB characteristics. The thermal-induced local convection over Nam Co can trigger the formation of extensive graupel clusters near the BB height, which in turn forms an area with abnormally high reflectivity. These findings not only enhance the understanding of precipitation microphysical processes in high altitude areas but also provide theoretical basis for developing precise QPE algorithms for the TP.

Evolutionary developmental biology seeks to elucidate the developmental mechanisms underlying phenotypic evolution. Central to this endeavor is the quantitative analysis of morphological variation, for which morphometric approaches have become indispensable tools. While morphometric methods have been extensively applied in paleontological research across diverse fossil groups, certain taxa remain underexplored. Among these, ostracods (Crustacea) represent a particularly promising yet underutilized group for such analyses. The suitability of ostracods for evolutionary and developmental investigations stems from several key attributes: their near-ubiquitous distribution across aquatic habitats, a remarkable taxonomic and morphological diversity, and an exceptional fossil record spanning geological time scales. Traditional morphometric approaches are constrained by the time-intensive nature of data acquisition, limiting the extent of achievable datasets. To address this bottleneck, we evaluate the efficacy of AutoMorph, a high-throughput imaging pipeline, for automated extraction of size and shape data from ostracod valves. We apply this approach to two ostracod species, Leucocythere dorsotuberosa and Leucocytherella sinensis, sampled from six lakes across the Tibetan Plateau, a region offering aquatic ecosystems with high endemism, providing an ideal setting for investigating ecological and evolutionary responses through morphological approaches. Our findings demonstrate that the AutoMorph pipeline successfully extracts morphometric measurements and coordinate data from ostracod valves, substantially reducing processing time while minimizing subjective bias inherent in manual approaches. This methodological advancement facilitates the generation of extensive datasets, thereby enabling more comprehensive investigations of ecological and evolutionary processes on large spatial and temporal scales.

Alpine rivers rapidly transport large-stored dissolved carbon (DC) from glaciers and alpine permafrost to downstream aquatic ecosystems. The Tibetan Plateau (TP) is an extraordinarily high-altitude region with ubiquitous alpine rivers undergoing intensified changes due to climate changes. However, the potential impacts on the magnitude and properties of DC in alpine rivers still remain poorly understood. Here, we examined the spatio-temporal variability of DC concentrations and properties across 14 alpine rivers in the central TP. Based on monthly investigations conducted during the open water season, the average concentration of dissolved organic carbon (DOC) and inorganic carbon (DIC) in TP alpine rivers was 1.03 f 0.73 and 14.73 f 13.05 mg L-1, respectively. The aromatic degree of dissolved organic matter (DOM) was relatively high with mean SUVA254 of 4.18 f 1.52 L mg C-1 m-1. Moreover, DOC export rate was found more intensive in glacier fed streams (0.017 f 0.015 g C km-2 s-1) was found than nonglacier fed rivers (0.009 f 0.011 g C km-2 s-1). Multiple regression models indicate that riverine DC concentrations were overwhelmingly elevated by vegetation coverage within the subbasins. In the glacier recharging catchments, inputs of summer glacier meltwater significantly enhanced terrigenous humic-like DOM (with higher SUVA254) flushing, which caused nearly constant riverine DOM over seasons. In contrast, nonglacier fed rivers were characterized by a sharp decline in DOM during the post monsoon season. These findings suggest a future scenario of heightened terrestrial leaching and riverine export of DC, driven by the expansion of vegetations and increased glacier derived DOM subsidy under ongoing climate warming and wetting on the TP.

A central objective of the NamCore ICDP project is to understand Quaternary biotic dynamics—specifically species diversity, distribution, and evolution—in relation to Asian monsoon variability and orbitally driven climate change. Lacustrine ostracodes are therefore ideal indicators to assess (1) whether Nam Co served as a glacial refugium for cold-adapted species during glacial periods, (2) how biota responded to glacial–interglacial environmental transitions, and (3) whether the lake exhibits a high ecological resilience to environmental change.To address these objectives, a multi-scale analytical approach was applied. Ostracode valve analyses were conducted on 43 core catcher samples spanning depths from 8 m to 470 m b.l.f., corresponding to a stratigraphic resolution represented by intervals of 3–35 m, to provide an overview of broad-scale changes in ostracode distribution and abundance. To obtain higher-resolution data on species distribution and morphological variability, additional samples from core sections within the upper 33 m b.l.f. were analyzed at 16 cm intervals. Morphometric analyses of valve outline shape and size are intended to identify either gradual or abrupt changes in morphological variability. Environmentally driven morphological responses are expected to manifest as gradual shifts in size and/or shape, whereas re-colonization from other lakes may produce distinct morphological signatures, resulting in discontinuous variation in size or shape.Preliminary results indicate that ostracode abundance and species composition are highly variable, with ostracodes absent below 470 m b.l.f. In total, ten species were identified, with a maximum of five species per sample. Generally, samples from the uppermost 30 m contain four species that are absent in the lower sections of the record. Although Leucocytherella sinensis and ?Leucocythere dorsotuberosa represent the most abundant taxa, no species occurs continuously throughout the sedimentary record.Detailed analyses of species composition, combined with morphometric investigations, are expected to elucidate whether the discontinuous ostracode distribution pattern reflects repeated lake colonization events associated with, e.g. glacial–interglacial cycles. Such findings would have significant implications for understanding the role of the Tibetan Plateau as a biodiversity refugium during Quaternary climate oscillations and for reconstructing paleoenvironmental conditions from ostracode assemblages in high-altitude lake systems.

Quantitative reconstruction of lake-level changes at Nam Co is essential for the understanding long-term environmental evolution and climate dynamics of the Tibetan Plateau. Ostracod-based transfer functions for water depth serve as valuable tools for quantitative lake-level reconstructions. However, their reliability at Nam Co has been constrained by limited spatial and depth coverage, insufficient robustness testing, and weak crossvalidation with independent regional proxies. To address these limitations, we integrated ostracod assemblages from multiple regions and applied comparative modeling to construct a more robust transfer function for Nam Co. This function was then used to reconstruct lake-level changes since the mid-late Holocene. Our results indicate that ostracod samples collected in different years exhibit no significant compositional differences, allowing their consolidation into a comprehensive lake-wide calibration dataset and improving model representativeness. Reconstructions generated through various statistical approaches revealed broadly consistent lakelevel trends, supporting the robustness of the findings. By applying a random forest transfer function based on the integrated dataset, we quantitatively reconstructed the lake-level fluctuations at Nam Co since the mid-late Holocene. The reconstruction reveals a sequence of humid-arid phases followed by a return to humid conditions, closely aligned with other regional paleoclimatic records. These results demonstrate the strong applicability of the model to Nam Co. Further analysis suggests that these fluctuations were likely influenced by the combined effects of the Indian Summer Monsoon, glacial meltwater, and Westerly air masses.

The Indian and East Asian Summer Monsoons are key atmospheric controls on hydrological variability across the Tibetan Plateau. This region, often referred to as the Asian Water Tower, provides freshwater resources for approximately two billion people via the major river systems that originate there. Consequently, reliable hydrological projections require improved constraints on the timing, duration, and magnitude of climate variability, and an understanding of the environmental responses to this change, in this climatically sensitive high-altitude region, particularly over long geological timescales.Nam Co is one of the largest and deepest lakes on the Tibetan Plateau (4,718 m a.s.l.; 2,020 km2 surface area; 98.9 m max. water depth; 10,680 km2 catchment area) and is an exceptional archive for investigating long-term climatic and environmental variability. To reconstruct past long-term climate variability and to examine its impacts, the lake was chosen as a target for ICDP drilling (NamCore) to recover a long, continuous record, with the aim of examining paleoenvironmental evolution, geomicrobiology, tectonics, and paleomagnetism. During the field operations conducted between May and July 2024, a total of 1415.45 m was drilled and 1175.99 m cored with 950.77 m of sediment recovered (core recovery of 80.8 %). Comparisons between magnetic susceptibility from (i) borehole logging, (ii) whole-round sediment cores, and (iii) core catcher material show widely similar trends across the depth dimension, suggesting a highly accurate depth control of the drilling depths recorded.Here, we present an overview of the project and sedimentological perspectives on the recovered sequence based on an integrated dataset comprising (i) core catcher material, (ii) sediment core samples and (iii) spectrophotometer and magnetic susceptibility measurements supported by (iv) detailed lithostratigraphic descriptions. The NamCore sedimentary succession is subdivided into five lithological units, defined by variations in (i) carbonate content and carbonate mineralogy, (ii) grain-size distributions, (iii) colour (likely related to iron speciation), and (iv) frequency-dependent magnetic susceptibility. The succession is characterised by recurring transitions among four lithofacies: (i) calcareous mud, (ii) ferric-stained calcareous mud, (iii) fine- to medium-grained sand, and (iv) non-calcareous mud. These alternations are interpreted to reflect major climatic and/or environmental changes, including variations in water-column, redox conditions, sediment accumulation rates, fluctuations in the extent of surrounding mountain glaciers, and broader-scale shifts in atmospheric circulation over the Tibetan Plateau associated with glacial–interglacial climate variability, changes in Pleistocene climate boundary conditions and related changes in catchment processes. In particular, colour shifts (green/red, a*) may represent shifts between warmer and wetter to colder and drier climatic conditions, whereas variations in frequency-dependent magnetic susceptibility likely reflect changes in pedogenesis, both of which might be linked to large-scale hydroclimatic forcing.

Study region: Longmu Co, a deep hypersaline lake in the western Tibetan Plateau, located in a cold, arid region dominated by the westerlies. Study focus: The annual mixing regime, under-ice thermal evolution, and relative roles of salinity, thermal forcing, and meteorological variability in deep hypersaline Tibetan Plateau lakes remain poorly understood. We investigated the thermodynamic regime of Longmu Co using 451 days of high-frequency water-temperature observations, a vertical salinity profile, concurrent meteorological measurements, bathymetric data, and satellite-derived ice phenology. TEOS-10-based density calculations and decomposition of squared buoyancy frequency showed that salinity provided the dominant background stability, separating a seasonally active mixolimnion from a persistently isolated monimolimnion. The mixolimnion exhibited cold monomictic circulation, mixing once annually from mid-November to early February, whereas the deep water column remained density-stratified. During complete ice cover, upper-water temperatures increased after early February, indicating a distinct under-ice thermal transition before ice breakup. Thermal forcing governed seasonal upper-layer stratification, while wind produced rapid but shallow perturbations. New hydrological insights for the region: In deep hypersaline lakes of the high-altitude western Tibetan Plateau, persistent haline stratification can prevent full-depth overturn despite strong westerly winds and severe winter cooling. Meteorological forcing acts mainly within the mixolimnion. This buffering effect explains why such lakes may remain meromictic and should be represented explicitly in regional lake models and assessments of climate-driven hydrological change.

The Tibetan Plateau (TP) is highly sensitive to variations in both the Asian summer monsoon and the mid-latitude westerlies. However, how these circulation systems jointly regulate lake and glacier hydrology remains insufficiently constrained, particularly in the westerly-monsoon transition zone. Here we reconstruct the Holocene hydrological evolution of Chibuzhang Co in the central TP using an integrated lipid biomarker approach involving glycerol dialkyl glycerol tetraethers (GDGTs), hydrogen isotopes of n-fatty acids (delta D FAs), and long-chain alkenones (LCAs). The multiproxy record reveals four distinct hydrological phases since 12.7 cal kyr BP. During the early Holocene, negative delta D FAs values together with low lake levels suggest a stronger influence of glacial meltwater under relatively cold and arid conditions. Between similar to 9.2 and 5 cal kyr BP, strengthened Indian summer monsoon precipitation maintained a lake highstand and low salinity, corresponding to the Holocene Thermal Maximum. In the mid-to-late Holocene, enhanced westerlies promoted glacier advances and intermittent meltwater input at centennial-to-millennial timescales but could not offset the moisture deficit caused by a weakened monsoon. Variations in temperature influenced evaporation and played a major role in regulating effective moisture. The asynchronous evolution of lake level and glacier extent indicates that lakes and glaciers did not respond synchronously to monsoon-westerly dynamics. These results provide constraints on the relative roles of precipitation, evaporation, and meltwater in Holocene lake evolution on the TP and may help to better understand regional hydrological sensitivity under future climate change.

The relationship between prehistoric human lifestyles and environmental change is a central focus in studies of human evolution and adaptation. However, there remains limited understanding of how prehistoric human activities on the Tibetan Plateau (TP)-one of the most challenging environments on Earth-adapted to climatic and hydrological changes. Here, we extracted the fecal stanols which can reflect human and herbivore activities from a lake core located in the middle-upper reaches of the Yarlung Zangbo River Basin since the last deglacial period, and combined them with other indicators reflecting environmental changes to analyze the relationship between prehistoric human activities and environmental changes in the lake basin. Prehistoric human activity in the Angrenjin Co Basin was strongly influenced by variations in surface runoff, lake levels, and summer temperatures. Before 16 cal ka BP, no human activity was detected via fecal stanols in the sediment core. The first signs of human presence emerged around similar to 15.5 cal ka BP, followed by long-term human activity between 8.8 and 4.2 cal ka BP, a period characterized by stable mid-level lake stands and warm climate. Despite increased aridity after 4.2 cal ka BP that reduced lake levels and runoff, human activity persisted, likely supported by the rise of pastoralism and agriculture. Notably, extreme precipitation events had more pronounced impacts on human populations than on large herbivores, whereas frequent lake-level fluctuations exerted stronger effects on herbivore dynamics during prehistoric times. These findings enhance our understanding of human-herbivore-environment interactions on the TP and warn global lakeside communities of extreme precipitation risks during persistent heat and drought, urging enhanced preparedness.

The Nam Co Drilling Project (NamCore) is a multinational and interdisciplinary research initiative designed to understand long-term climatic variability and associated environmental change on the Tibetan Plateau. The project primarily targets the timing and magnitude of Indian/East Asian monsoon variability and its interplay with the Westerlies. Thereby, the glacial-interglacial history and dynamics at high altitude; the impact of geological and environmental changes on (micro-)biological processes; the evolution and resilience of high-altitude ecosystems, including the deep biosphere; and geomagnetic variations during the Quaternary are of special interest.For in-depth investigations regarding the outlined research purposes, the (mostly) calcareous sediments of Nam Co, one of the largest and deepest lakes on the Tibetan Plateau, were targeted within the framework of the International Continental Scientific Drilling Program (ICDP) and cored in May-July 2024 (ICDP Expedition 5073). Altogether, 1415.45 m was drilled and 1175.99 m cored, with 950.77 m of sediment recovered (core recovery of 80.8 %) from seven holes at one site (5073_1) situated at a water depth of similar to 93 m, reaching a maximum depth of 510.2 m below the lake floor. Initial results from core descriptions and preliminary core catcher analyses suggest that the sediments of Nam Co reflect the evolution of a dynamic high-altitude lake system over multiple glacial-interglacial cycles. Four major lithologies are observed in the drill cores (calcareous mud, non-calcareous mud, calcareous mud with ferric staining and sand) and grouped into five major lithological units based on their physicochemical characteristics obtained from core catcher material. Micropaleontological results from core catcher material reveal a general absence of diatoms, due to unsuitable growing and/or preservation conditions, while ostracods abundances, preservation, and species composition vary, which might be linked to environmental changes and/or changing preservation conditions. Shifts in n-alkane chain length might be attributable to lake-level variations and/or glacial-interglacial cycles.

The Tibetan Plateau hosts the world's highest-altitude lake cluster, which constitutes a critical component of regional hydrological cycles and plays a vital role in regulating regional climate and maintaining ecological balance. The lake water balance dominated by the input(Precipitation +glacial meltwater)/evaporation (I/E) reflect regional water cycle changes and climatic changes. This study reconstructs the regional hydroclimate evolution and explored its driving mechanisms over the past 25.1 cal ka BP using high-resolution mineralogical composition (XRD analysis) and authigenic carbonate stable isotope records (delta C-13(carb) and delta O-18(carb)) from sediment cores in central Tibetan Plateau's Serling Co. Our findings reveal that Serling Co remained relatively small and shallow under cold-arid conditions throughout the last deglacial period, experiencing multiple climatic fluctuations. During the Early-Mid Holocene, the lake expanded significantly under warm-humid conditions with stable hydrological status, followed by rapid contraction and frequent dry-wet alternations in the Late Holocene. Orbital-scale variations in solar insolation controlling thermal conditions and monsoonal precipitation emerge as primary drivers of climatic changes, while AMOC and ENSO variations induced centennial-millennial scale hydrological fluctuations. Notably under low insolation conditions during the Last Deglacial and Late Holocene periods, the lake exhibited reduced stability and enhanced hydrological vulnerability. This investigation elucidates Serling Co's paleoclimate history and its driving mechanisms, emphasizing the crucial role of water balance dynamics in interpreting lacustrine climate archives, thereby providing valuable insights for understanding long-term hydrological changes in the Tibetan Plateau's lake systems.

The Tibetan Plateau, with an average elevation of 4000 m above sea level, is the highest plateau on Earth. It is the third largest store of ice after the Arctic and Antarctic and is often referred to as the ‘Third Pole’. It is an area sensitive to climate shifts and is expected to go through significant warming in the future. Nam Co in central Tibet is located in the modern monsoon regime and was recently drilled as part of the ICDP NamCore drilling project, which aims to reconstruct the Quaternary climate history of the region. Lake sediments act as paleoenvironmental archives; with minerals forming in the water column reflecting the prevailing environmental conditions, which then become part of the sediment package after deposition. However, post-depositional processes, such as early diagenesis, can cause alteration in mineralogy, structure and/or chemistry of deposited sediments. This can happen through sediment compaction, fluid circulation and physico-chemical changes, often mediated by microbial activity in situ. We report results about authigenic minerals and mineral evolution in Nam Co. The aim is to target different diagenetic formation pathways of pyrite by combining detailed structural and compositional data, such as high-resolution X-ray computed micro-tomography (μCT), X-ray fluorescence scanning, and sulphur isotope analyses. We hypothesise the formation of pyrite in Nam Co happens because of diagenetic processes and pathways driven by changes in hydrology and limnology, tectonically induced fluid flow, and microbial activity. The overarching aim is to disentangle these different formation processes, and to assess whether we can use the sulphur isotope composition of pyrite to discriminate between environmental and tectonic controls.

Ontogenetic information remains limited for many cypridoid ostracods despite its importance for reliable taxonomy, species identification, and the interpretation of ecological patterns based on size and morphology. This is particularly relevant in paleoecological studies, where, usually, only valves are preserved. We investigated post-embryonic development in three asexual species of Heterocypris inhabiting ephemeral aquatic environments: Heterocypris exodonta from the Tibetan Plateau, Heterocypris incongruens from Mexico, and Heterocypris salina from Germany. Based on laboratory cultures maintained under controlled conditions, egg morphology, juvenile valve development, and ontogenetic growth were quantified using measurements of valve length and height. All three species exhibited nine developmental stages, comprising eight juvenile instars and one adult stage. Eggs possess a rough external surface and a distinct internal eggshell structure. Early juvenile stages display a marked polygonal reticulation pattern on their valves that progressively weakens and disappears in adults. Growth ratios, defined as the proportional increase in valve size between successive developmental stages, averaged values close to those expected under geometric growth. However, considerable variation is reported among species and developmental stages. The results provide reference data on ontogenetic development and diagnostic morphological characters, improving the distinction between juvenile stages and both intraspecific and interspecific variation and supporting the interpretation of modern and fossil assemblages.

Abstract Aquatic ecosystems have changed dramatically, but the relative roles of external forcings and internal atmospheric variability remain unclear. Here, using Tibetan lake ecological reconstructions and Earth system simulations, we reveal how shared external forcings shaped Tibetan Plateau limnoecology over the past millennium through two distinct pathways. In the temperature-centric pathway, cooling episodes driven by volcanic activity and internal variability likely regulated preindustrial lake conditions. This baseline was disrupted as recent forced warming has shortened lake ice-cover and increased meltwater input, altering lake resources and triggering unprecedented diatom shifts. In the freshening-centric pathway, salinity-tolerant diatoms tracked monsoon-driven precipitation changes and lake freshening, both governed by shifts in the intertropical convergence zone. Preindustrial shifts likely reflected hemispherically asymmetric orbital and volcanic forcings, whereas modern changes have been altered remarkably by Northern Hemisphere industrial aerosol fluctuations and warming-induced meltwater. As multifaceted stressors intensify, Tibetan lake ecosystems may continue diverging from their natural variability.

Environmental changes on the Tibetan Plateau (TP) and their responses to the Indian summer monsoon (ISM) and the westerlies have attracted significant attention. However, our understanding of regional vegetation and climate changes influenced by the ISM from the Arabian Sea and the westerlies in the southwestern TP remains limited. Here, we present a pollen record from Lake Mapam Yumco covering the late deglacial to the Holocene. Results show that alpine meadow was sparsely distributed around the lake, with relatively high moisture from 13.5 to 11.7 cal ka BP. The early Holocene (11.7-8.3 cal ka BP) was the most humid period, marked by persistent alpine meadow and expanding steppe. During 8.3-4.2 cal ka BP, the climate became drier, with alpine meadow steppe dominating. After 4.2 cal ka BP, vegetation shifted to sparse dry steppe. Moisture conditions at Lake Mapam Yumco were humid in the late deglacial and early Holocene but drier in the late Holocene compared to the eastern TP, due to the ISM from different pathways and the influence of the southern branch of the westerlies. The stepwise drying trend in the Holocene reflects that the regional climate was mainly controlled by the ISM, which was driven by the summer insolation at 30 degrees N and the position of the Intertropical Convergence Zone. Exotic pollen studies underscore the crucial role of the westerlies and El Nino-Southern Oscillations in atmospheric circulation. Dry events in the Holocene highlight that the North Atlantic region also impacts the climate in the southwestern TP.

Study region Mang Co, a dimictic freshwater lake in the southeastern Tibetan Plateau (TP) influenced by the summer monsoon, lies within the Jinsha River catchment. The region experiences warm, humid summers and cold, dry winters. Study focus Using a three-year (2019-2022) high-resolution (30-min interval) vertical water temperature dataset, we investigated Mang Co's seasonal thermal stratification and mixing dynamics, and compared controlling mechanisms with those of arid mid-western TP lakes. New hydrological insights Mang Co exhibits monsoon-driven humidity amplification (annual mean up to 60 %), which suppresses evaporative cooling and maintains hypolimnetic temperatures up to similar to 10 degrees C-significantly warmer than those in mid-western TP lakes where the climate is drier. Stratification develops from late May to early October, followed by spring and autumn overturning and similar to 4 months of winter ice cover with inverse stratification, and post-melt convection. Episodic spring wind gusts (>10 ms(-)(1)) drive mixing. Summer stratification is mainly stabilized by air temperature and humidity-radiation synergy, unlike arid lakes where wind and solar radiation dominate. Due to Mang Co's shallow depth and low salinity, the thermocline is shallower (similar to 10 m) and Schmidt stability lower (max similar to 194 Jm(-)(2)) than in deeper saline lakes. These findings highlight divergent thermal structures shaped by humidity, wind events, and ice-water interactions. They underscore the importance of incorporating humidity thresholds and episodic wind forcing into lake models for accurately simulating monsoon-affected high-altitude lakes under climate change.

The Tibetan Plateau (TP), known as the “Third Pole” and “Roof of the World”, is a pivotal regulator of the Earth’s climate due to its vast high-altitude terrain, which drives atmospheric circulation, influences monsoon dynamics, and amplifies global climate feedbacks. Yet, comprehensive syntheses of the TP’s paleoclimate evolution-particularly spanning the Last Glacial Maximum (LGM) to the Holocene-remain fragmented, thereby obscuring mechanistic links between regional climatic shifts and global forcings. To address this gap, we present a systematic review of lake and ice core-based paleoclimate records across the TP, covering the past 25,000 years. By synthesizing multi-proxy datasets—including δ1⁸O, the Westerlies Climate Index, total organic carbon (TOC), sediment-transport indicators, glycerol dialkyl glycerol tetraether (GDGT) ratios, aquatic macrophyte index (Paq), aquatic biomarkers, lithic flux and effective-moisture reconstructions—we evaluate interactions among atmospheric circulation, monsoon variability, cryospheric changes, and radiative forcing components. Our synthesis highlights the TP’s dual sensitivity to both the Indian Summer Monsoon (ISM) and mid-latitude westerlies, positioning it as a “climatic amplifier” of hemispheric-scale changes. Variations in solar insolation, ice-sheet feedbacks, and oceanic teleconnections primarily drove major transitions from glacial aridity to Holocene humidity. Spatial heterogeneity is evident, with the TP’s northwestern margins showing distinct responses to ISM variability. High-resolution ice-core and biomarker records further reveal abrupt climatic shifts-such as the Younger Dryas cooling and the Holocene Thermal Maximum- underscoring the plateau’s active role in global climate dynamics. To clarify Holocene patterns, we integrated well-dated regional records across the TP, revealing spatially variable responses to monsoon and westerly influence. Despite substantial progress, significant knowledge gaps remain: (1) sparse records from the TP’s northwestern interior limit understanding westerly-monsoon interactions; (2) dating uncertainties in loess and lake archives hinder precise event chronology; and (3) proxy-based temperature and precipitation signals remain challenging to disentangle. Future research should prioritize high-resolution, multi-proxy lake sediment records, particularly from underrepresented regions of the TP. Improved chronological control and the development of more sensitive, climate-specific proxies are essential to refine regional reconstructions. Such integrated approaches will improve our understanding of the TP’s climatic role and its vulnerability to ongoing anthropogenic warming.

Lakes on the Tibetan Plateau, highly sensitive to environmental changes, play a key role in paleoclimatic studies. However, dating limitations often constrain investigations to periods before the Last Glacial Maximum (LGM). Relative paleointensity (RPI) of lake sediments offers a valuable means of developing high-resolution chronological frameworks during the Brunhes Chron. This study presents an RPI record from a lacustrine sediment core (NMC2020-1A) from Nam Co, Tibetan Plateau (TP), based on normalization of natural remanent magnetization (NRM) by anhysteretic remanent magnetization (ARM) over 20-60 mT demagnetization range using the slope method. Rock magnetic analyses indicate pseudo-single domain (PSD (≈vortex) magnetite as the dominant magnetic mineral. Five age control points were identified by correlating the RPI record with the PISO-1500 paleointensity stack. An age model for the 38.71-10.8 m upper section of the core has been established, covering 78 to 25 ka. The environmental magnetic parameter κARM/κ exhibits a clear precession cycle, highlighting the sensitivity of environmental changes on the TP to variations in solar radiation. Furthermore, comparisons of the κARM/κ ratio at the millennial scale with stalagmite and Greenland ice core records demonstrate the influence of high-latitude abrupt climate shifts on the climate of the TP.

Hydroclimate variations in the Tibetan Plateau, particularly its southeastern region, significantly influence downstream agricultural and ecological systems. However, the dynamics of these changes remain inadequately understood. In this study, we present a 28.6 thousand-year record of precipitation hydrogen isotopes (SDp) derived from sedimentary leaf wax n-alkanoic acids (C30, SDwax) from Mang Co Lake, a lake in the southeastern Tibetan Plateau. Our analysis interprets SDp as a proxy for Indian Summer Monsoon (ISM) intensity, revealing its strongest phase during both the early Holocene and 28.6-26.5 calibrated thousand years before present (Cal ka BP), as well as its weakest during the Last Glacial Maximum (LGM). We find that summer insolation is the primary driver of ISM variability on the orbital scale over the past 28.6 ka. Millennial scale SDp variability reflects interactions between the summer monsoon and the westerly jet (WJ). The SDp record reveals that in the periods of 5-3 Cal ka BP and 1-0 Cal ka BP, a weakened ISM coincided with the WJ's prolonged residence south of the Tibetan Plateau. Abrupt cooling events due to albedo feedback of ice and snow in high latitudes are inferred to have played a critical role in modulating the atmospheric circulation patterns, including the position and intensity of the WJ and ISM. Our findings emphasize the high sensitivity of the southeastern Tibetan Plateau's hydroclimate to global climate changes, necessitating future reconstructions with improved temporal and spatial resolution.

The Asian summer monsoon's variability significantly impacts water resource management in densely populated Asia, yet its dynamics across various time scales are not fully understood. While stalagmite oxygen isotope records suggest a temporal link between the slowdown of the Atlantic Meridional Overturning Circulation (AMOC) and the weakening of the Asian summer monsoon during the last glacial period, the patterns of monsoonal precipitation changes remain poorly understood. In this study, we employ geochemical and lithologic proxies, including Fe/Mn ratio, grain-size end members, and calcium carbonate content, to reconstruct monsoonal precipitation changes over the past 28.6 thousand years based on a continuous sediment core from Mang Co Lake, located on the southeastern edge of the Tibetan Plateau. Our reconstruction identifies wet intervals of 26-23, 20-18.5, 17.5-16, and 14-0 Cal ka BP, and dry intervals of 28.6-26, 23-20, 18.5-17.5, and 16-14 Cal ka BP. The millennial-scale wet intervals in the Yangtze River basin, including the Mang Co region, during the last glacial period are associated with southward displacements of the westerly jet. We also find an inverse relationship between precipitation in the Mang Co region and tropical rainfall, observable on both interannual and millennial timescales. Instrumental observations from recent decades reveal a negative correlation between annual mean precipitation in the Yangtze River basin and tropical Asia. Additionally, wet intervals in the Mang Co record align with intensifications of the Indonesian-Australian monsoon, suggesting southward displacements of the Intertropical Convergence Zone (ITCZ). We infer that the inverse correlation between subtropical and tropical precipitation variability is due to the concurrent meridional displacement of the westerly jet and the ITCZ. This study underscores the importance of the meridional organization of atmospheric circulation components in modulating monsoonal precipitation variations and calls for further reconstruction and modelling endeavors to elucidate the underlying mechanisms.