scholarly journals Recent Spatiotemporal Trends in Glacier Snowline Altitude at the End of the Melt Season in the Qilian Mountains, China

2021 ◽  
Vol 13 (23) ◽  
pp. 4935
Author(s):  
Zhongming Guo ◽  
Ninglian Wang ◽  
Baoshou Shen ◽  
Zhujun Gu ◽  
Yuwei Wu ◽  
...  
Keyword(s):  
Qilian Mountains ◽  
Equilibrium Line ◽  
Upward Trend ◽  
Equilibrium Line Altitude ◽  
Spatiotemporal Trends ◽  
Mean Temperature ◽  
Basin Scale ◽  
Annual Total ◽  
Central Eastern ◽  
The Qilian Mountains

Glaciers in the Qilian Mountains, China, play an important role in supplying freshwater to downstream populations, maintaining ecological balance, and supporting economic development on the Tibetan Plateau. Glacier snowline altitude (SLA) at the end of the melt season is an indicator of the Equilibrium line altitude (ELA), and can be used to estimate the mass balance and climate reconstruction. Here, we employ the height zone-area method to determine the SLA at the end of the melt season during the 1989–2018 period using Landsat, MODIS (Moderate Resolution Imaging Spectroradiometer) SLA and Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) data. The accuracy of glacier SLA obtained in 1989–2018 after adding MODIS SLA data to the years without Landsat data increased by about 78 m. The difference between the remote-sensing-derived SLA and measured equilibrium line altitude (ELA) is mostly within 50 m, suggesting that the SLA can serve as a proxy for the ELA at the end of the melt season. The SLA of Qiyi Glacier in the Qilian Mountains rose from 4690 ± 25 m to 5030 ± 25 m, with an average of 4900 ± 103 m during the 30 year study period. The western, central, eastern sections and the whole range of the Qilian Mountains exhibited an upward trend in SLA during the 30 year study period. The mean glacier SLAs were 4923 ± 137 m, 4864 ± 135 m, 4550 ± 149 m and 4779 ± 149 m for the western, central, eastern sections and the whole range, respectively. From the perspective of spatial distribution, regardless of the different orientation, grid scale and basin scale, the glacier SLA of Qilian Mountains showed an upward trend from 1989 to 2018, and the glacier SLA is in general located at a comparably higher altitude in the southern and western parts of the Qilian Mountains while it is located at a comparably lower altitude in its northern and eastern parts. In an ideal condition, climate sensitivity studies of ELA in Qilian Mountains show that if the summer mean temperature increases (decreases) by 1 °C, then ELA will increase (decrease) by about 102 m. If the annual total solid precipitation increases (decreases) by 10%, then the glacier ELA will decrease (rise) by about 6 m. The summer mean temperature is the main factor affecting the temporal trend of SLA, whereas both summer mean temperature and annual total precipitation influence the spatial change of SLA.

Variations in equilibrium line altitude of the Qiyi Glacier, Qilian Mountains, over the past 50 years

2010 ◽  
Vol 55 (33) ◽  
pp. 3810-3817 ◽  
Author(s):  
NingLian Wang ◽  
JianQiao He ◽  
JianChen Pu ◽  
Xi Jiang ◽  
ZheFan Jing
Keyword(s):  
Qilian Mountains ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
The Past

MAY-JUNE MEAN TEMPERATURE RECONSTRUCTION OVER THE PAST 300 YEARS BASED ON TREE RINGS IN THE QILIAN MOUNTAINS OF THE NORTHEASTERN TIBETAN PLATEAU

IAWA Journal ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 421-434 ◽  
Author(s):  
Qinhua Tian ◽  
Xiaohua Gou ◽  
Yong Zhang ◽  
Yongsheng Wang ◽  
Zexin Fan
Keyword(s):  
Regional Climate ◽  
Ring Width ◽  
Temperature Reconstruction ◽  
Qilian Mountains ◽  
Temperature Record ◽  
Sabina Przewalskii ◽  
Mean Temperature ◽  
The Qilian Mountains ◽  
Past 300 Years

A juniper (Juniperus przewalskii Kom.; synonym: Sabina przewalskii) tree-ring width chronology was developed to investigate the regional climate variability for the Qilian Mountains. Statistically, the chronology was appropriate for reconstructing the regional mean temperature of May-June from A.D.1700 to the present. The phenomenon of synchronous extremely high temperatures and extreme droughts in the 1920s was revealed by comparing our reconstruction with drought events in this region. Multi-taper spectral analysis indicated the existence of significant low- and high-frequency periods (40–46 years, 34, 23–25, 5.6, 2.1, 2.5–2.8 years). Overall, the study not only extended the temperature record, but also provided reliable long-term temperature information to help understand the possible forcing of climate changes in the Qilian Mountains.

scholarly journals Temperature and precipitation climate at the equilibrium-line altitude of glaciers expressed by the degree-day factor for melting snow

2008 ◽  
Vol 54 (186) ◽  
pp. 437-444 ◽  
Author(s):  
Roger J. Braithwaite
Keyword(s):  
Summer Precipitation ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
Temperature Relation ◽  
High Accumulation ◽  
Melting Snow ◽  
Temperature Range ◽  
Degree Day ◽  
Temperature And Precipitation ◽  
Mean Temperature

AbstractSeveral authors relate accumulation (or precipitation) at the glacier equilibrium-line altitude (ELA) to summer mean temperature using exponential or power-law functions. I analyze the accumulation–temperature relation at the ELA with a degree-day model using data from the 1992 paper by A. Ohmura and others. The dataset includes estimates at the ELA of winter balance and of ‘winter balance plus summer precipitation’ which represent respectively low and high estimates of annual accumulation, which is seldom measured. The Ohmura dataset only lists summer mean temperature, but I recover monthly temperatures for the whole year for 66 of the glaciers by assuming sinusoidal temperature variation through the year and using annual temperature range from a gridded climatology. Monthly degree-day sums are then estimated from monthly mean temperature and summed to give annual totals so degree-day factors for melting snow at the ELA are obtained. The degree-day factors fall close to those reported in the literature for glacier snowmelt, with averages of 3.5 ± 1.4 and 4.6 ± 1.4 mm d−1 K−1 for low- and high-accumulation estimates on the 66 glaciers. The degree-day model gives a family of accumulation–temperature curves that depend upon the annual temperature range, representing the contrast between maritime and continental climates.

scholarly journals Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1015
Author(s):  
Xuan Wu ◽  
Liang Jiao ◽  
Dashi Du ◽  
Changliang Qi ◽  
Ruhong Xue
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Central Region ◽  
Radial Growth ◽  
Growing Season ◽  
Qilian Mountains ◽  
Growth Patterns ◽  
Total Precipitation ◽  
Picea Crassifolia ◽  
The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

scholarly journals Mapping and Evaluating Human Pressure Changes in the Qilian Mountains

2021 ◽  
Vol 13 (12) ◽  
pp. 2400
Author(s):  
Quntao Duan ◽  
Lihui Luo ◽  
Wenzhi Zhao ◽  
Yanli Zhuang ◽  
Fang Liu
Keyword(s):  
Human Activities ◽  
Qilian Mountains ◽  
Western China ◽  
Eastern Region ◽  
Human Pressure ◽  
Activity Intensity ◽  
Human Footprint ◽  
Illegal Activities ◽  
The Qilian Mountains ◽  
The Impact

Human activities have dramatically changed ecosystems. As an irreplaceable ecological barrier in western China, the Qilian Mountains (QLM) provide various ecosystem services for humans. To evaluate the changes in the intensity of human activities in the QLM and their impact on the ecosystem, the human footprint (HF) method was used to conduct a spatial dataset of human activity intensity. In our study, the NDVI was used to characterize the growth of vegetation, and six categories of human pressures were employed to create the HF map in the QLM for 2000–2015 at a 1-km scale. The results showed that the mean NDVI during the growing season showed a significant increasing trend over the entire QLM in the period 2000–2015, while the NDVI showed a significant declining trend of more than 70% concentrated in Qinghai. Human pressure throughout the QLM occurred at a low level during 2000–2015, being greater in the eastern region than the western region, while the Qinghai area had greater human pressure than the Gansu area. Due to the improvement in traffic facilities, tourism, overgrazing, and other illegal activities, grasslands, shrublands, forests, wetlands, and bare land were the vegetation types most affected by human activities (in decreasing order). As the core area of the QLM, the Qilian Mountains National Nature Reserve (NR) has effectively reduced the impact of human activities. However, due to the existence of many ecological historical debts caused by unreasonable management in the past, the national park established in 2017 is facing great challenges to achieve its goals. These data and results will provide reference and guidance for future protection and restoration of the QLM ecosystem.

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