scholarly journals Rock glacier characteristics under semiarid climate conditions in the Western Nyainqêntanglha range, Tibetan Plateau

2022 ◽  
Author(s):  
Johannes Buckel ◽  
Eike Reinosch ◽  
Anne Voigtländer ◽  
Michael Dietze ◽  
Matthias Bücker ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Rock Glacier ◽  
Climate Conditions ◽  
Semiarid Climate

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.

Nitrate accumulation reduction using chloride in the nutrient solution on lettuce growing by NFT in semiarid climate conditions

1998 ◽  
Vol 21 (8) ◽  
pp. 1705-1714 ◽  
Author(s):  
Miguel Urrestarazu ◽  
Adela Postigo ◽  
Maricarmen Salas ◽  
Agustín Sánchez ◽  
Gilda Carrasco
Keyword(s):  
Nutrient Solution ◽  
Nitrate Accumulation ◽  
Climate Conditions ◽  
Semiarid Climate

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.

Inventory of active rock glaciers in the western Nyainqêntanglha Range, Tibetan Plateau

2021 ◽  
Author(s):  
Eike Reinosch ◽  
Markus Gerke ◽  
Björn Riedel ◽  
Antje Schwalb ◽  
Qinghua Ye ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Reliability ◽  
Surface Velocity ◽  
Windward Side ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Automated Classification ◽  
Rock Glacier ◽  
North West ◽  
Rock Glaciers

<p>The western Nyainqêntanglha Range on the Tibetan Plateau (TP) reaches an elevation of 7162 m and is characterized by an extensive periglacial environment. Here, we present the first rock glacier inventory of the central TP containing 1433 rock glaciers over an area of 4622 km². The rock glaciers are identified based on their surface velocity. The surface velocity is derived from Sentinel-1 satellite data of 2016 to 2019 via InSAR time series analysis. 16.4 % of the inventoried rock glaciers are classified as active with a surface velocity above 10 cmyr<sup>-1</sup> and 80.0 % are classified as transitional with 1 to 10 cmyr<sup>-1</sup>. The western Nyainqêntanglha Range forms a climate divide between the dry continental climate brought by the Westerlies from the north-west and the Indian Summer Monsoon to the south. 89.7 % of all active rock glaciers and 74 % of the free ice glacial area are located on the southern side. The higher moisture availability on the southern (windward) side of the mountain range is likely the cause of a higher rock glacier occurrence and the greater activity.</p><p>Manually identifying and outlining rock glaciers is time consuming and subjective. To ensure a high reliability and comparability of our inventory, we therefore combined a manual approach with an automated classification. Three analysts worked in tandem to generate the manual outlines according to the guidelines of the IPA action group on ‘Rock glacier inventories and kinematics’. A subset of these outlines acted as training areas for a pixel-based maximum likelihood classification. Both the manual and the automated classification were performed based on DEM parameters (elevation, slope etc.), optical datasets (Sentinel-2 and NDVI) and surface velocity (generated with InSAR). 87.8 % of all manually outlined rock glaciers were identified successfully at a true positive rate of 69.5 %. 18 additional rock glaciers were added to the inventory based on the automated classification. This combined approach is therefore beneficial to generate a complete inventory. The automated classification can, however, not replace the expertise of an analyst as it greatly overestimates the actual rock glacier area.</p>

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