scholarly journals Quantifying streamflow and active groundwater storage in response to climate warming in an alpine catchment on the Tibetan Plateau

2018 ◽  
Author(s):  
Lu Lin ◽  
Man Gao ◽  
Jintao Liu ◽  
Xi Chen ◽  
Hu Liu
Keyword(s):  
Tibetan Plateau ◽  
Climate Warming ◽  
Storage Capacity ◽  
Flow Analysis ◽  
Summer Rainfall ◽  
Dominant Factor ◽  
The Tibetan Plateau ◽  
Early Winter ◽  
Frozen Ground ◽  
Groundwater Storage

Abstract. Climate warming is changing streamflow regimes and groundwater storage in cold alpine regions. In this study, a headwater catchment named Yangbajain in the Lhasa River basin on the Tibetan Plateau is adopted as the study area for quantifying streamflow changes and active groundwater storage in response to climate warming. The catchment is characterized by alpine glacier and frozen ground which covers about 11 % and 86 % of the total area, respectively. The changes in streamflow regimes (including quickflow and baseflow) and climate factors are evaluated based on hydro-meteorological observations from 1979 to 2013. Then active groundwater storage in autumn and early winter is quantified by recession flow analysis assuming nonlinearized outflow from aquifers into streams. The results show that annual streamflow increases significantly at a rate of about 12.30 mm/10a during this period. The significant increase of annual air temperature compared with nonsignificant variation of annual precipitation indicates that the climate warming takes responsibilities to the increase of streamflow. It is believed that the increased streamflow is mainly fed by glacier meltwater, which has led to over 25 % loss of the total glacial volume in the past 50 years (1960–2009) in this catchment. Moreover, the significant increase of annual baseflow at a rate of about 10.95 mm/10a is the dominant factor for the increase of the total streamflow. Through recession flow analysis, we find that recession coefficient K and active groundwater storage S in autumn and early winter increase significantly at the rates of about 7.70 (mm0.79d−0.21)/10a and 19.32 mm/10a during these years. The increase of active groundwater storage can partly be explained by frozen ground degradation, which lead to the enlargement of groundwater storage capacity and accommodate more summer rainfall and meltwater in the wide and flat valley, and then slowly release them into streams in the following seasons. Thus, it is reasonable to attribute the increase of baseflow and the slowdown of baseflow recession process in autumn and early winter to the enlargement of groundwater storage capacity. Through quantifying streamflow changes and active groundwater storage in response to warming-induced changes, this study provides a perspective to clarify the way of glacial retreat and frozen ground degradation on hydrological processes.

scholarly journals Elevational Movement of Vegetation Greenness on the Tibetan Plateau: Evidence from the Landsat Satellite Observations during the Last Three Decades

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 161
Author(s):  
Liheng Lu ◽  
Xiaoqian Shen ◽  
Ruyin Cao
Keyword(s):  
Tibetan Plateau ◽  
Spatial Resolution ◽  
Climate Warming ◽  
Vertical Movement ◽  
The Tibetan Plateau ◽  
Upward Movement ◽  
Vegetation Growth ◽  
Vegetation Greenness ◽  
Mountainous Regions ◽  
Vegetation Activities

The Tibetan Plateau, the highest plateau in the world, has experienced strong climate warming during the last few decades. The greater increase of temperature at higher elevations may have strong impacts on the vertical movement of vegetation activities on the plateau. Although satellite-based observations have explored this issue, these observations were normally provided by the coarse satellite data with a spatial resolution of more than hundreds of meters (e.g., GIMMS and MODIS), which could lead to serious mixed-pixel effects in the analyses. In this study, we employed the medium-spatial-resolution Landsat NDVI data (30 m) during 1990–2019 and investigated the relationship between temperature and the elevation-dependent vegetation changes in six mountainous regions on the Tibetan Plateau. Particularly, we focused on the elevational movement of the vegetation greenness isoline to clarify whether the vegetation greenness isoline moves upward during the past three decades because of climate warming. Results show that vegetation greening occurred in all six mountainous regions during the last three decades. Increasing temperatures caused the upward movement of greenness isoline at the middle and high elevations (>4000 m) but led to the downward movement at lower elevations for the six mountainous regions except for Nyainqentanglha. Furthermore, the temperature sensitivity of greenness isoline movement changes from the positive value to negative value by decreasing elevations, suggesting that vegetation growth on the plateau is strongly regulated by other factors such as water availability. As a result, the greenness isoline showed upward movement with the increase of temperature for about 59% pixels. Moreover, the greenness isoline movement increased with the slope angles over the six mountainous regions, suggesting the influence of terrain effects on the vegetation activities. Our analyses improve understandings of the diverse response of elevation-dependent vegetation activities on the Tibetan Plateau.

scholarly journals Response of melt water and rainfall runoff to climate change and their roles in controlling streamflow changes of the two upstream basins over the Tibetan Plateau

2019 ◽  
Vol 51 (2) ◽  
pp. 272-289 ◽  
Author(s):  
Yueguan Zhang ◽  
Zhenchun Hao ◽  
Chong-Yu Xu ◽  
Xide Lai
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Dominant Factor ◽  
Model Parameters ◽  
Glacier Mass Balance ◽  
The Tibetan Plateau ◽  
Rainfall Runoff ◽  
Snowmelt Runoff ◽  
Infiltration Capacity ◽  
Total Runoff

Abstract Located in the Tibetan Plateau, the upstream regions of the Mekong River (UM) and the Salween River (US) are very sensitive to climate change. The ‘VIC-glacier‘ model, which links a degree-day glacier algorithm with variable infiltration capacity (VIC) model, was employed and the model parameters were calibrated on observed streamflow, glacier mass balance and MODIS snowcover data. Results indicate that: (1) glacier-melt runoff exhibits a significant increase in both areas by the Mann–Kendall test. Snowmelt runoff shows an increasing trend in the UM, while the US is characterized by a decreasing tendency. In the UM, the snowmelt runoff peak shifts from June in the baseline period 1964–1990 to May for both the 1990s and 2000s; (2) rainfall runoff was considered as the first dominant factor driving changes of river discharge, which could be responsible for over 84% in total runoff trend over the two regions. The glacial runoff illustrates the secondary influence on the total runoff tendency; (3) although the hydrological regime is rain dominated in these two basins, the glacier compensation effect in these regions is obvious, especially in dry years.

Soil and vegetation feedbacks on climate change in high mountain ranges of the Tibetan Plateau__using near and mid-infrared spectroscopy (FT-NMIRS) in soil properties, phosphorus (P) as example

2020 ◽  
Author(s):  
Zuonan Cao ◽  
Peter Kühn ◽  
Thomas Scholten
Keyword(s):  
Global Warming ◽  
Infrared Spectroscopy ◽  
Tibetan Plateau ◽  
Soil Quality ◽  
Climate Warming ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
P Fractions ◽  
Mid Infrared ◽  
Warming Rate

<p>The Tibetan Plateau is the third-largest glaciated area of the world and is one of the most sensitive regions due to climate warming, such as fast-melting permafrost, dust blow and overgrazing in recent decades. In the past 50 years, the warming rate on the Tibetan Plateau is higher than the global average warming rate with 0.40 ± 0.05 °C per decade. The climate warming is most distinct in the northeastern Tibetan Plateau, implying increasing air and surface temperatures as well as duration and depth of thawing. The main ecological consequences are a disturbed vegetation cover of the surface and a depletion of nutrient-rich topsoils (Baumann et al., 2009, 2014) coupled with an increase of greenhouse gas emissions, mainly CO<sub>2</sub> (Bosch et al., 2017). Due to the extreme environmental conditions resulting from the intense and rapid tectonic uplift, highly adaptive and sensitive ecosystem have developed, and the Plateau is considered to be a key area for the environmental evolution of Earth on regional and global scales, which is particularly sensitive to global warming (Jin et al., 2007; Qiu, 2008). Climate warming and land-use change can reduce soil organic carbon (SOC) stocks as well as soil nitrogen (N) and phosphorus (P) contents and soil quality. Many species showed their distributions by climate-driven shifts towards higher elevation. In Tibetan Plateau, however, the elevational variations of the alpine grassland are rare (Huang et al., 2018) and it is largely unknown how the grass line will respond to global warming and whether soils play a major role. With this research, the hypothesis is tested that soil quality, given by SOC, N and P stocks and content, is a driving factor for the position and structure of the grass line and that soil quality is one of the major controls of biodiversity and biomass production in high-mountain grassland ecosystems.</p><p>A Fourier transformation near and mid-infrared spectroscopy (FT-NMIRS) should be used to measure soil P fractions rapid and for large numbers of soil samples, and analyze environmental factors, including temperature, precipitation, soil development, soil fertility, and the ability of plants to adapt to the environmental impact of climate using FT-NMIRS.</p><p>We explored first near-infrared spectroscopy (NIRS) in soils from grassland on the Tibetan Plateau, northwestern China and extracted P fractions of 196 samples from Haibei Alpine Meadow Ecosystem Research Station, Chinese Academy of Sciences, at four depths increments (0-10 cm 10-20 cm 20-40 cm and 40-70 cm) with different pre-nutrient additions of nitrogen (N) an P. The fractionation data were correlated with the corresponding NIRS soil spectra and showed significant differences for depth increments and fertilizer amendments. The R<sup>2</sup> of NIRS calibrations to predict P in traditional Hedley fractions ranged between 0.12 and 0.90. The model prediction quality was higher for organic than for inorganic P fractions and changed with depth and fertilizer amendment. The results indicate that using NIRS to predict the P fractions can be a promising approach compared with traditional Hedley fractionation for soils in alpine grasslands on the Tibetan Plateau.</p>

scholarly journals A new map of permafrost distribution on the Tibetan Plateau

2017 ◽  
Vol 11 (6) ◽  
pp. 2527-2542 ◽  
Author(s):  
Defu Zou ◽  
Lin Zhao ◽  
Yu Sheng ◽  
Ji Chen ◽  
Guojie Hu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Spatial Data ◽  
Land Surface ◽  
Future Research ◽  
Data Sets ◽  
The Tibetan Plateau ◽  
Freezing And Thawing ◽  
Frozen Ground ◽  
Distribution Maps ◽  
Spatial Data Sets

Abstract. The Tibetan Plateau (TP) has the largest areas of permafrost terrain in the mid- and low-latitude regions of the world. Some permafrost distribution maps have been compiled but, due to limited data sources, ambiguous criteria, inadequate validation, and deficiency of high-quality spatial data sets, there is high uncertainty in the mapping of the permafrost distribution on the TP. We generated a new permafrost map based on freezing and thawing indices from modified Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperatures (LSTs) and validated this map using various ground-based data sets. The soil thermal properties of five soil types across the TP were estimated according to an empirical equation and soil properties (moisture content and bulk density). The temperature at the top of permafrost (TTOP) model was applied to simulate the permafrost distribution. Permafrost, seasonally frozen ground, and unfrozen ground covered areas of 1.06  ×  106 km2 (0.97–1.15  ×  106 km2, 90 % confidence interval) (40 %), 1.46  ×  106 (56 %), and 0.03  ×  106 km2 (1 %), respectively, excluding glaciers and lakes. Ground-based observations of the permafrost distribution across the five investigated regions (IRs, located in the transition zones of the permafrost and seasonally frozen ground) and three highway transects (across the entire permafrost regions from north to south) were used to validate the model. Validation results showed that the kappa coefficient varied from 0.38 to 0.78 with a mean of 0.57 for the five IRs and 0.62 to 0.74 with a mean of 0.68 within the three transects. Compared with earlier studies, the TTOP modelling results show greater accuracy. The results provide more detailed information on the permafrost distribution and basic data for use in future research on the Tibetan Plateau permafrost.

scholarly journals Skillful prediction of summer rainfall in the Tibetan Plateau on multiyear time scales

2021 ◽  
Vol 7 (24) ◽  
pp. eabf9395
Author(s):  
Shuai Hu ◽  
Tianjun Zhou
Keyword(s):  
Tibetan Plateau ◽  
Time Scales ◽  
North Atlantic ◽  
Prediction Models ◽  
Summer Rainfall ◽  
The Tibetan Plateau ◽  
Silk Road Pattern ◽  
Near Term ◽  
Asian Water ◽  
The Silk Road

Skillful near-term climate predictions of rainfall over the Tibetan Plateau (TP), the Asian water tower, benefit billions of people. On the basis of the state-of-the-art decadal prediction models, we showed evidence that although the raw model outputs show low predicted ability for the summer Inner TP (ITP) rainfall due to low signal-to-noise ratios in models, we can produce realistic predictions by extracting the predictable signal from large ensemble predictions along with a postprocessing procedure of variance adjustment. The results indicate that the summer ITP rainfall is highly predictable on multiyear time scales. The predictability of ITP rainfall originates from the Silk Road pattern driven by sea surface temperature over the subpolar gyre region in North Atlantic. Real-time forecasts suggest that the ITP will become wetter, with 12.8% increase in rainfall during 2020–2027 relative to 1986–2005. Our results will help the water resources management in the surrounding regions.

The responses of dominant tree species to climate warming at the treeline on the eastern edge of the Tibetan Plateau

2018 ◽  
Vol 425 ◽  
pp. 21-26 ◽  
Author(s):  
Mingming Guo ◽  
Yuandong Zhang ◽  
Xiaochun Wang ◽  
Fengxue Gu ◽  
Shirong Liu
Keyword(s):  
Tibetan Plateau ◽  
Climate Warming ◽  
Tree Species ◽  
The Tibetan Plateau ◽  
Eastern Edge
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