A preliminary estimate of how stream water age is influenced by changing runoff sources in the Nagau river water shed, Qinghai‐Tibet Plateau

2021 ◽  
Author(s):  
Yuheng Yang ◽  
Baisha Weng ◽  
Denghua Yan ◽  
Xiaoyan Gong ◽  
Yanyu Dai ◽  
...  
Keyword(s):  
River Water ◽  
Stream Water ◽  
Tibet Plateau ◽  
Preliminary Estimate ◽  
Water Age ◽  
Qinghai Tibet Plateau

Using Stable Isotopes to Estimate Stream Water Age in the Qinghai-Tibet Plateau

2020 ◽  
Author(s):  
Yuheng Yang ◽  
Baisha Weng
Keyword(s):  
Climate Change ◽  
Stream Water ◽  
Tibet Plateau ◽  
Isotopic Data ◽  
Water Age ◽  
Glacial Ice ◽  
Water Fraction ◽  
Relative Age ◽  
Stable Isotopic ◽  
Qinghai Tibet Plateau

<p>Stream water age is an essential indicator of stream water renewal and pollutant transport rates in the Qinghai-Tibet Plateau (QTP). Recently, the concept of a young water fraction (F<sub>yw</sub> , calculated using stable isotopic data, was proposed as a measure of stream water age. The relative age of older stream in streams has yet to be quantified, however. In this study, we proposed a method to calculate the relative proportions of middle-aged and old-age water in runoff. The results revealed that in the Nagqu watershed, an average of 23% of the runoff was < 51.6 days old, whereas an average of 55% of the runoff had ages ranging from 51.6 days to 1. The change in stream water age is significantly influenced by the runoff composition, evaporation, air temperature, and soil moisture at a depth of 20 cm. The amount of stored glacial ice, soil ice, snow cover, groundwater, and other old water in the QTP appears to be decreasing under the influence of climate change. The results of this study are helpful for the study of runoff composition and stream water age, as well as their responses to climate change.</p>

Geochemical and Isotope Tracers Reveal the Runoff Components Characteristics and the Ecohydrologic Influences at the Qinghai-Tibet Plateau

2020 ◽  
Author(s):  
Hongwei Liu ◽  
Jiufu Liu ◽  
Jin Lin ◽  
Wenzhong Wang ◽  
Xing Min ◽  
...  
Keyword(s):  
Ground Water ◽  
River Water ◽  
Laser Scanning ◽  
Base Flow ◽  
Tibet Plateau ◽  
Vacuum Extraction ◽  
Observation Data ◽  
Runoff Change ◽  
Geochemical Elements ◽  
Qinghai Tibet Plateau

<p>The glacier recession and the runoff variation on the Qinghai-Tibet plateau conducted by the global warming is changing the regional hydrological and ecological processes. Although there is great need for the knowledge of the runoff evolution and biogenic substances migration and transformation for developing strategies for adaptive utilization of runoff, progress in study on these hydrological questions lags behind because of lack of observation dataset under harsh plateau cold conditions.</p><p>In order to understand the critical zone ecohydrological dynamics and evaluate the runoff components in the Qinghai-Tibet Plateau, a series of observation and research were carried out in the Niyang River watershed, a tributary of the Yarlung Zangbo River. Four basins embed in a larger basin (1500 km<sup>2</sup>) were monitored and sampled at altitudes between 3667 to 6140 m. More than 500 samples from rain, snow, river water, spring water, glacier ice, vegetation stem, and soil were collected, with which theδ<sup>2</sup>H, δ<sup>18</sup>O, K, Ca, Na, Mg, Sr, Si, F, Cl, N, and S in the water are examined. 5 automatic hydrometric stations were established, and the water level data was sent back by Beidou satellite. The 3D laser scanning and RTK technologies were used to obtain detailed geomorphological information near the 5 current measurement section, based on which a hydrodynamic model is able to be calibrated for the discharge estimation.</p><p>The δ<sup>2</sup>H and δ<sup>18</sup>O of the precipitation proposed a local meteoric water isotope line, which is parallel to the WMWL but higher in the δD~δ<sup>18</sup>O graph. The river water isotopes suggest its source is the precipitation, which are similar to the spring ground water (but the geochemical elements are quite different between the surface and ground water). The vegetation stems water and soil water (by cryogenic vacuum extraction) isotope values suggest the attribute of the river/precipitation sources, but a few observation data appear different implying using water formed by the multiple precipitation events or supplied by the higher place under a significant evaporation influence.</p><p>The time series of the runoff and the snow cover and glacier variation results show that the base flow is varied obviously relate to the temperature which influence the melting processes of the glacier and frozen earth from March to August, and the rain runoff events control the flood peek. It suggests that the concentration time should be less than 10 days in the interested watershed.</p><p>The tempo-spatial variation characteristics of the geochemical elements are analyzed and mapped in the interested area, which suggested relative steady water components signals contributing to the runoff. Based on which, a set of overdetermined equations are established to evaluate the quantities of different runoff components.</p><p>This study could help to evaluate runoff components quantitively in Tibet where lack of data. Monitoring and studing is still going on, which is included in the 2<sup>nd</sup> comprehensive scientific investigation into Qinghai-Tibet Plateau since 2019.</p><p>Funded by the NSFC project 91647111 and 91647203 included in the Runoff Change and its Adaptive Management in the Major Rivers in Southwestern China Major Research Plan.</p>

Calibrating a hydrological model in a regional river of the Qinghai–Tibet plateau using river water width determined from high spatial resolution satellite images

2018 ◽  
Vol 214 ◽  
pp. 100-114 ◽  
Author(s):  
Wenchao Sun ◽  
Jiao Fan ◽  
Guoqiang Wang ◽  
Hiroshi Ishidaira ◽  
Satish Bastola ◽  
...  
Keyword(s):  
River Water ◽  
Spatial Resolution ◽  
Satellite Images ◽  
Hydrological Model ◽  
High Spatial Resolution ◽  
Tibet Plateau ◽  
Qinghai Tibet Plateau

The effect of permafrost area and types on flux and composition of dissolved organic matter in stream from alpine catchments, northeastern Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Yanxi Pan ◽  
Ziyong Sun
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
River Water ◽  
Frozen Soil ◽  
Tibet Plateau ◽  
Vegetation Coverage ◽  
Permafrost Degradation ◽  
Terrestrial Organic Matter ◽  
The Impact ◽  
Qinghai Tibet Plateau

<p>Understanding optical characteristics, composition and source of dissolved organic matter (DOM) in rivers is important for region and global carbon cycle, especially in the inland rivers of the Qinghai-Tibet Plateau. In order to understand the impact of permafrost degradation on river DOM output under the background of climate warming, we selected 34 typical sub-basins in the upper reaches of the Heihe River basin on the Qinghai-Tibet Plateau according to the different proportion of permafrost area in the basin. Water samples were collected at the outlet of each sub-basin in October 2018, January, April and July 2019, respectively. The variations of DOM structure and source identification in different permafrost basin were investigated using UV–visible absorbance and fluorescence spectroscopy. The results showed that: (1) The concentration of C1 and C2 components and the values ​​of SUVA<sub>254</sub>, HIX and FI increased with the decrease of the percentage of permafrost area. , Indicating that with the degradation of frozen soil, the runoff path deepens, and more terrestrial organic matter is dissolved into the water body, which increases the terrestrial DOM in the river water, which in turn leads to the increase of DOM concentration, humification degree and aromaticity; (2) As the proportion of permafrost area decreases, the S<sub>R</sub> value shows a decreasing trend, indicating that the DOM of rivers in permafrost regions has the characteristics of low molecular weight and low humic acid, while the DOM of rivers in seasonally frozen soil regions is the opposite, indicating a frozen soil Melting may lead to the increase of terrestrial DOM in river water, and the increase in the depth of freeze-thaw cycle may release aromatic substances containing fused ring structure in frozen soil, which will enter the river with runoff, resulting in increased aromaticity and molecular weight of DOM in river water; (3) The concentrations of C1 and C2 components are positively correlated with vegetation coverage, and vegetation coverage is negatively correlated with the percentage of permafrost area. It shows that the degradation of frozen soil will increase the coverage of vegetation, thereby increasing the DOM from terrestrial sources. This study shows that the optical characteristics, composition and source of DOM have important indications for the degradation of permafrost under the background of global warming.</p>

Characteristics of isotope in precipitation, river water and lake water in the Manasarovar basin of Qinghai–Tibet Plateau

2008 ◽  
Vol 57 (3) ◽  
pp. 551-556 ◽  
Author(s):  
Zhijun Yao ◽  
Jian Liu ◽  
He-Qing Huang ◽  
Xianfang Song ◽  
Xiaohui Dong ◽  
...  
Keyword(s):  
River Water ◽  
Lake Water ◽  
Tibet Plateau ◽  
Qinghai Tibet Plateau

Soil Respiration of Subalpine Coniferous Forest in Winter in the East of the Qinghai-Tibet Plateau，China*

2010 ◽  
Vol 2009 (6) ◽  
pp. 761-767
Author(s):  
Feifei ZHOU ◽  
Bo LIN ◽  
Qing LIU ◽  
Weiming LI
Keyword(s):  
Soil Respiration ◽  
Coniferous Forest ◽  
Tibet Plateau ◽  
Subalpine Coniferous Forest ◽  
Qinghai Tibet Plateau

Legacy effect of warming on the heterotrophic respiration of alpine grassland on the Qinghai-Tibet Plateau

2021 ◽  
Vol 166 ◽  
pp. 104093
Author(s):  
Fei Peng ◽  
Wenjuan Zhang ◽  
Chimin Lai ◽  
Chengyang Li ◽  
Quangang You ◽  
...  
Keyword(s):  
Heterotrophic Respiration ◽  
Alpine Grassland ◽  
Tibet Plateau ◽  
Legacy Effect ◽  
Qinghai Tibet Plateau
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