scholarly journals THE NUMERICAL SIMULATION OF ASTRO-CLIMATE CONDITIONS OVER THE TIBETAN PLATEAU

2015 ◽  
Vol 30 (2) ◽  
pp. 695-697
Author(s):  
XUAN QIAN ◽  
YONGQIANG YAO ◽  
HONGSHUAI WANG ◽  
LIYONG LIU
Keyword(s):  
Numerical Simulation ◽  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Climate Conditions

scholarly journals Potential Production of Carbon Gases and Their Responses to Paleoclimate Conditions: An Example From Xiaolongtan Basin, Southeast Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Gen Wang ◽  
Yongli Wang ◽  
Zhifu Wei ◽  
Zepeng Sun ◽  
Wei He ◽  
...  
Keyword(s):  
Organic Matter ◽  
Tibetan Plateau ◽  
Low Temperature ◽  
Organic Carbon ◽  
Carbon Cycle ◽  
Higher Plants ◽  
The Tibetan Plateau ◽  
Climate Conditions ◽  
Burial Flux ◽  
Carbon Gases

Uplift of the Tibetan Plateau plays a significant and lasting role in the variations of climate conditions and global carbon cycle. However, our knowledge is limited due to the lack of long-sequence records revealing rates of CO2 and CH4 production, hampering our understanding of the relationship between paleoclimatic conditions, carbon cycling and greenhouse gas flux. Here, we present a combination of paleoclimate records and low-temperature thermal simulation results from sediments of the Xiaolongtan Basin at the southeastern margin of the Qinghai-Tibetan Plateau, spanning the late Miocene (14.1 ∼ 11.6 Ma). The n-alkane-derived proxies suggested that the sources of organic matter were obviously different: a mixed source including lower organisms and terrestrial higher plants for the Dongshengqiao Formation from 14.1 to 12.6 Ma, and a predominant contribution from terrestrial higher plants for Xiaolongtan Formation between 12.6 and 11.6 Ma. The paleoclimate was generally warm and humid as reflected by the lipid biomarkers, consistent with previous studies. In addition, the carbon gases (including CO2 and hydrocarbon gases) generated by the low-temperature thermal simulation experiments indicated a production rate of CO2 and CH4 were as high as 88,000 ml/kg rock and 4,000 ml/kg rock, respectively, implying there were certain amounts of carbon gases generated and released into the atmosphere during their shallow burial stage. Besides, the calculated production rate of carbon gases and the estimated burial flux of organic carbon varied in response to the variations of paleoclimate conditions. Based on these observations, we propose that the climate conditions predominantly controlled the formation and accumulation of organic matter, which consequently affected the production of carbon gases and burial flux of organic carbon. The results presented here may provide a significant insight into the carbon cycle in the southeast of the Tibetan Plateau.

Origin and formation model of Eocene dolomite in the upper Niubao Formation of Lunpola Basin, Tibetan Plateau

2021 ◽  
pp. 1-50
Author(s):  
Xiaoquan Chen ◽  
Fengcun Xing ◽  
Shu Jiang ◽  
Yongchao Lu ◽  
Zhongrong Liu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Hot Springs ◽  
Northern China ◽  
Hydrothermal Fluids ◽  
Lake Basin ◽  
The Tibetan Plateau ◽  
Climate Conditions ◽  
Hot Climate ◽  
Strong Evaporation ◽  
Semi Arid

Using fresh cores samples, we determined the origin and formation process of Eocene lacustrine dolomites in the Tibetan Plateau through petrological, mineralogical, and geochemical analyses. Dolomitic rocks were collected from the upper member of Eocene Niubao Formation in the Lunpola Basin, and consist of dolomitic mudstone, argillaceous dolomite, dolomite-bearing mudstone and mud-bearing dolomite. These dolomites are dominated by aphanotopic and micro-crystalline dolomites, with minor amounts of euhedral or subhedral powder- and fine-crystalline dolomites. Carbon and oxygen stable isotopes, combined with ubiquitous gypsum in study area, indicates a semi-saline continental lake under strong evaporative conditions. The revealed relatively high temperature of dolomitization(33.8°C–119.1°C), combined with hydrothermal minerals such as cerous phosphate and barite, reflect the participation of dolomite from hot fluids. Moreover, the inferred dolomitization temperatures decrease gradually toward the centre of the lake basin, suggesting the resurgence of hydrothermal fluids along a fault zone on the lake margin. This proves that frequent thermal events occurred at the boundary fault of the Lunpola Basin margin during early Himalayan orogenesis. In addition, Jurassic carbonates interacting with hydrothermal fluids, as well as strong evaporation conditions, likely provided favourable conditions for the formation of primary lime sediments. A rich source of Mg2+ brought by volcanic ash, hydrothermal fluids, and the Jurassic carbonates then created conditions for dolomitization during the depositional period. Strong evaporation under a relatively hot climate enhanced penecontemporaneous dolomitization, thus forming dolomite. Tibetan Plateau was under arid to semi-arid climate conditions, and there was a widespread distribution of dolostones in western, central, and northern China during the Eocene period. The hydrothermal dolomites of the upper Niubao Formation testify for active hot springs, while lacustrine dolomite imply arid or semi-arid climates during the Eocene, in the early stages of Himalayan orogenesis.

Spatiotemporal characteristics of water budget dynamic in the Yarlung Tsangpo River basin of Tibetan Plateau based on multi-source datasets

2020 ◽  
Author(s):  
Yao Jiang ◽  
Zongxue Xu
Keyword(s):  
Tibetan Plateau ◽  
River Basin ◽  
Water Budget ◽  
Water Resource Management ◽  
The Tibetan Plateau ◽  
Water Budgets ◽  
Climate Conditions ◽  
Basin Scale ◽  
Yarlung Tsangpo ◽  
Yarlung Tsangpo River

<p>Understanding the dynamics of basin-scale water budgets over the Tibetan Plateau (TP) is significant for hydrology and water resource management in the southern and eastern Asia. However, a detailed water balance analysis is limited by the lack of adequate hydro-climatic observations in this region. In this study, we investigate the spatiotemporal variation of water budget components (e.g. precipitation P, evapotranspiration ET and runoff Q etc.) in the Yarlung Tsangpo River basin (YTB) of southeast TP during the period of 1975-2015 through using multi-source datasets (e.g. insitu observation, remote sensing data products, reanalysis outputs and model simulations etc.). The change trend of water budget components and vegetation parameters was analyzed in the YTB on interannual scale. The results indicated that the detailed water budgets are different from upstream to downstream YTB due to different temperature, vegetation cover and evapotranspiration, which are mainly affected by different climate conditions. In the whole basin, precipitation that are mainly during June to October was the major contributor to the runoff. The P and Q were found to show a slight but insignificant decrease in most regions of YTB since the late 1990s, which showed positive relationships with the weakening Indian summer monsoon. While the ET showed an insignificant increase across most of the YTB, especially in the middle basin. The runoff coefficient (Q/P) exhibited an indistinctively decreasing trend which may be, to some extent, due to the overlap effects of ET increase and snow and glacier changes. The obtained results offer insights into understanding the evolution mechanism of hydrological processes in such a data-sparse region under changing environment.</p>

Quantitative climate and vegetation trends since the late glacial on the northeastern Tibetan Plateau deduced from Koucha Lake pollen spectra

2009 ◽  
Vol 71 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Ulrike Herzschuh ◽  
Annette Kramer ◽  
Steffen Mischke ◽  
Chengjun Zhang
Keyword(s):  
Tibetan Plateau ◽  
Vegetation Change ◽  
Late Glacial ◽  
Quantitative Information ◽  
The Tibetan Plateau ◽  
Climate History ◽  
Climate Conditions ◽  
Northeastern Tibetan Plateau ◽  
Vegetation And Climate ◽  
Cool Climate

AbstractQuantitative information on vegetation and climate history from the late glacial–Holocene on the Tibetan Plateau is extremely rare. Here, we present palynological results of a 4.30-m-long sediment record collected from Koucha Lake in the Bayan Har Mountains, northeastern Tibetan Plateau. Vegetation change has been traced by biomisation, ordination of pollen data, and calculation of pollen ratios. The application of a pollen–climate calibration set from the eastern Tibetan Plateau to Koucha Lake pollen spectra yielded quantitative climate information. The area was covered by alpine desert/steppe, characteristic of a cold and dry climate (with 50% less precipitation than today) between 16,700 and 14,600 cal yr BP. Steppe vegetation, warm (∼ 1°C higher than today) and wet conditions prevailed between 14,600 and 6600 cal yr BP. These findings contradict evidence from other monsoon-influenced areas of Asia, where the early Holocene is thought to have been moist. Low effective moisture on the northeastern Tibetan Plateau was likely due to high temperature and evaporation, even though precipitation levels may have been similar to present-day values. The vegetation changed to tundra around 6600 cal yr BP, indicating that wet and cool climate conditions occurred on the northeastern Tibetan Plateau during the second half of the Holocene.

scholarly journals OSL Chronology of the Siling Co Paleolithic Site in Central Tibetan Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Lan Luo ◽  
Zhongping Lai ◽  
Wenhao Zheng ◽  
Yantian Xu ◽  
Lupeng Yu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ground Surface ◽  
Early Holocene ◽  
Archaeological Sites ◽  
Stratigraphic Correlation ◽  
The Tibetan Plateau ◽  
Paleolithic Site ◽  
Humid Climate ◽  
Climate Conditions ◽  
Central Tibetan Plateau

When and how was the Tibetan Plateau (TP), one of the least habitable regions on Earth, occupied by humans are important questions in the research of human evolution. Among tens of Paleolithic archaeological sites discovered over the past decades, only five are considered coeval with or older than the Last Glacial Maximum (LGM, ∼27–19 ka). As one of them, the Siling Co site in the central TP was previously announced to be ∼40–30 ka based on radiocarbon dating and stratigraphic correlation. Given the loose chronological constraint in previous studies, we here re-examined the chronology of the Siling Co site with the optically stimulated luminescence (OSL) dating technique. Four sections from the paleo-shoreline at an elevation of ∼4,600 m in southeastern Siling Co were investigated, with stone artifacts found from the ground surface. Dating results of nine samples delineated the age of ∼4,600 m paleo-shoreline to be ∼10–7 ka (∼8.54 ± 0.21 ka in average). This age indicates that the Siling Co site is not earlier than the early Holocene, much younger than the former age. The revised age of the Siling Co site is consistent with the wet and humid climate conditions on the TP during the early Holocene.

scholarly journals Magnitude Agreement, Occurrence Consistency, and Elevation Dependency of Satellite-Based Precipitation Products over the Tibetan Plateau

2020 ◽  
Vol 12 (11) ◽  
pp. 1750 ◽  
Author(s):  
Yibing Wang ◽  
Xianhong Xie ◽  
Shanshan Meng ◽  
Dandan Wu ◽  
Yuchao Chen ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Complex Terrain ◽  
Hydrological Modeling ◽  
Reference Data ◽  
Climate Prediction ◽  
The Tibetan Plateau ◽  
Spatiotemporal Resolution ◽  
Climate Conditions ◽  
Mean Square Errors ◽  
Climate Prediction Center

Satellite remote sensing is a practical technique to estimate global precipitation with adequate spatiotemporal resolution in ungauged regions. However, the performance of satellite-based precipitation products is variable and uncertain for the Tibetan Plateau (TP) because of its complex terrain and climate conditions. In this study, we evaluated the abilities of nine widely used satellite-based precipitation products over the Eastern Tibetan Plateau (ETP) and quantified precipitation dynamics over the entire TP. The evaluation was carried out from three aspects, i.e., magnitude agreement, occurrence consistency, and elevation dependency, from grid-cell to regional scales. The results show that the nine satellite-based products exhibited different agreement with gauge-based reference data with median correlation coefficients ranging from 0.15 to 0.95. Three products (climate hazards group infrared precipitation with stations (CHIRPS), multi-source weighted-ensemble precipitation (MSWEP), and tropical rainfall measuring mission multi-satellite precipitation analysis (TMPA)) generally presented the best performance with the reference data, even in complex terrain regions, given their root mean square errors (RMSE) of less than 25 mm/mon. The climate prediction center merged analysis of precipitation (CMAP) product has relatively coarse spatial resolution, but it also exhibited good performance with a bias of less than 20% in watershed scale. Two other products (precipitation estimation from remotely sensed information using artificial neural networks-cloud classification system (PER-CCS) and climate prediction center morphing technique-raw (CMORPH-RAW)) overestimated precipitation with median RMSEs of 87 mm/mon and 45 mm/mon, respectively. All the precipitation products generally exhibited better agreement with the reference data for rainy season and lower-elevation regions. All of the products captured precipitation occurrence well, with hit event over 60%, and similar percentages of missed and false event. According to the evaluation, the four products (CHIRPS, MSWEP, TMPA, and CMAP) revealed that the annual precipitation over the TP fluctuated between 333 mm/yr and 488 mm/yr during the period 2003 to 2015. The study indicates the importance of integration of multiple data sources and post-processing (e.g., gauge data fusion and elevation correction) for satellite-based products and have implications for selection of suitable precipitation products for hydrological modeling and water resources assessment for the TP.

scholarly journals Past the climate optimum: Recruitment is declining at the world’s highest juniper shrublines on the Tibetan Plateau

2020 ◽  
Author(s):  
Eryuan Liang ◽  
Xiaoming Lu ◽  
Yafeng Wang ◽  
Flurin Babst ◽  
Steven W. Leavitt ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Field Surveys ◽  
Climate Conditions ◽  
South Central ◽  
Subsequent Decrease ◽  
Central Tibetan Plateau ◽  
The World ◽  
Negative Impacts

<p>Alpine biomes are climate change hotspots, and treeline dynamics in particular have received much attention as visible evidence of climate-induced shifts in species distributions. Comparatively little is known, however, about the effects of climate change on alpine shrubline dynamics. Here, we reconstruct decadally resolved shrub recruitment history (age structure) through the combination of field surveys and dendroecology methods at the world’s highest juniper (Juniperus pingii var. wilsonii) shrublines on the south-central Tibetan Plateau. A total of 1,899 shrubs were surveyed at 12 plots located in four regions along an east-to-west declining precipitation gradient. We detected synchronous recruitment with 9 out of 12 plots showing a gradual increase from 1600 to 1900, a peak at 1900–1940, and a subsequent decrease from the 1930s onward. Shrub recruitment was significantly and positively correlated with reconstructed summer temperature from 1600 to 1940, whereas it was negatively associated with temperature in recent decades (1930–2000). Recruitment was also positively correlated with precipitation, except in the 1780–1830 period, when a trend toward wetter climate conditions began. This apparent tipping point in recruitment success coincides with a switch from positive to negative impacts of rising temperatures.  Warming-induced drought limitation has likely reduced the recruitment potential of alpine juniper shrubs in recent decades. Continued warming is thus expected to further alter the dynamics of alpine shrublines on the Tibetan Plateau and elsewhere.</p>

scholarly journals Numerical Simulation of the Carbon Cycle Over The Tibetan Plateau, China

2007 ◽  
Vol 39 (4) ◽  
pp. 723-731 ◽  
Author(s):  
Guangzhou Fan ◽  
Tingjun Zhang ◽  
Jinjun Ji ◽  
Kerang Li ◽  
Jiyuan Liu
Keyword(s):  
Numerical Simulation ◽  
Tibetan Plateau ◽  
Carbon Cycle ◽  
The Tibetan Plateau

OSL chronology of the Liena archeological site in the Yarlung Tsangpo valley throws new light on human occupation of the Tibetan Plateau

The Holocene ◽  
2020 ◽  
Vol 30 (7) ◽  
pp. 1043-1052
Author(s):  
Zhiyong Ling ◽  
Xiaoyan Yang ◽  
Yixuan Wang ◽  
Yanren Wang ◽  
Jianhui Jin ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Environmental Changes ◽  
Warm Period ◽  
Human Migration ◽  
The Tibetan Plateau ◽  
Human Occupation ◽  
Climate Conditions ◽  
The Holocene ◽  
Cultural Layers ◽  
Yarlung Tsangpo

Recent environmental archeological evidence has started to throw light on both the timing and processes of human colonization of the Tibetan Plateau (TP). Yarlung Tsangpo (YT) valley, a very important region of the southern TP for occupation, is home to not only modern Tibetans but also their ancestors. However, a lack of suitable sedimentary strata has limited the establishment of a secure chronology. Here, we report on a new stratigraphic section with prehistoric pottery and cultural layers that was discovered on a terrace of the YT at Liena, in Nyingchi County. The cultural layers are overlain by, and bedded within, eolian and lacustrine sediments. We used the quartz Optically Stimulated Luminescence (OSL) method to date 11 samples and performed geochemical analysis on 100 samples to derive paleoenvironmental indicators. The OSL analysis gave an age of 4.3 ka BP for the cultural layer, which makes it the earliest human activity in the YT valley of Nyingchi to date. In addition, commencement of eolian deposition was dated to at least 8.3 ka, coinciding with the Holocene warm period. We discuss possible causal factors for human occupation in the valley and show that climatic changes played a crucial role in prehistoric human migration c. 8.3–4.3 ka BP. Before the early Holocene, most of the river terraces in the valley were being actively reworked by rivers or covered by lakes. So there were no suitable places for occupation by ancient populations. With the recession of dammed lakes during the Holocene warm period, the relatively flat and wide valley terraces, blanketed with rich eolian deposits (such as sandy loess), provided an attractive place for ancient people engaged in nomadic and even agricultural activities. Hence, the climate conditions of the Holocene warm period drove the environmental changes that provided favorable conditions for ancient human activities.

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