• Zhongqin Li

Articles written in Journal of Earth System Science

• Ice thickness, volume and subglacial topography of Urumqi Glacier No. 1, Tianshan mountains, central Asia, by ground penetrating radar survey

The results of radar survey for three times are presented, aiming to determine ice thickness, volume and subglacial topography of Urumqi Glacier No. 1, Tianshan Mountains, central Asia. Results show that the distribution of ice is more in the center and lesser at both ends of the glacier. The bedrock is quite regular with altitudes decreasing towards the ice front, showing the U-shaped subglacial valley. By comparison, typical ice thinning along the centerline of the East Branch of the glacier was 10–18 m for the period 1981–2006, reaching a maximum of ∼30 m at the terminus. The corresponding ice volume was 10296.2 × 104 m3, 8797.9 × 104 m3 and 8115.0 × 104 m3 in 1981, 2001 and 2006, respectively. It has decreased by 21.2% during the past 25 years, which is the direct result of glacier thinning. In the same period, the ice thickness, area and terminus decreased by 12.2%, 10.3%, and 3.6%, respectively. These changes are responses to the regional climatic warming, which show a dramatic increase of 0.6°C (10 a)−1 during the period 1981–2006.

• Characteristics of water isotopes and hydrograph separation during the spring flood period in Yushugou River basin, Eastern Tianshans, China

Many of the river basins in northwest China receive water from melting glaciers and snow in addition to groundwater. This region has experienced a significant change in glacier and snowpack volume over the past decade altering hydrology. Quantifying changes in water resources is vital for developing sustainable strategies in the region. During 2013, a water-isotope source apportionment study was conducted during the spring flood in the Yushugou River basin, northwestern China. The study found significant differences in water isotopes between river water, snowmelt water, and groundwater. During the study period, the isotopic composition of groundwater remained relatively stable. This stability suggests that the groundwater recharge rate has not been significantly impacted by recent hydro-climatic variability. The river water flow rate and water 𝛿18O displayed an inverse relationship. This relationship is indicative of snowmelt water injection. The relative contribution of the two sources was estimated using a two-component isotope hydrograph separation. The contribution of snowmelt water and groundwater to Yushugou River were $\sim$63% and $\sim$37%, respectively. From the study, we conclude that snowmelt water is the dominant water source to the basin during the spring melt period.

• Run-off analyses using isotopes and hydrochemistry in Yushugou River basin, eastern Tianshan Mountains

Yushugou River basin of East Tianshan Mountains receives water from melting glaciers. In recent years, the glaciers retreated strongly due to global warming which intensified the water cycle in the river basin. For this reason, the relation of water bodies based on hydrochemistry and isotope in the summer flood was carried out. Hydrochemistry research showed that there was frequent hydraulic interaction between river water and groundwater. Studying the isotopes and Cl of river water, glacier meltwater, groundwater and precipitation, indicated that Yushugou River was recharged by the glacier meltwater, groundwater and precipitation during the summer flood period. The analysis result based on the three-component mixing model showed that Yushugou River was recharged by 54.9% of glacier meltwater, 37.6% of the run-off came from groundwater, while less than 8% was contributed by precipitation. The study suggests that the role of glacier meltwater and groundwater, especially glacier meltwater, should be specially concerned in water resource protection and reasonable utilization, and the injection of glacier meltwater is the main reason for run-off variation in this alpine basin during the summer flood period.

• Recent geodetic mass balance and extent changes of very small glaciers in the Hulugou Basin, Central Qilian Mountains, China

Very small glaciers (< 0.5 km$^{2}$) account for more than 70% of the total number of glaciers in the Qilian Mountains. Despite their total area and volume being small, they are important water resources in the Hexi Corridor. While glacier monitoring mostly focuses on medium-sized and large valley glaciers (e.g., Qiyi Glacier and Laohugou Glacier No. 12) in the Qilian Mountains, little is known about very small glacier mass balance in this region. This study presents a geodetic mass balance of six very small glaciers in the Hulugou Basin by comparing Shuttle Radar Topography Mission (SRTM) C-band (2000) and airborne laser scanning (2012) digital elevation models (DEMs). The total glaciers’ area decreased by 23.6% at a rate of 0.024 km$^{2}$ a$^{-1}$ and the geodetic mass balance was $-$0.68 $\pm$ 0.11 m water equivalent (m w.e.) a$^{-1}$ from 2000 to 2012. Shiyi Glacier, as the monitored glacier in the Basin, had lost 10.9% of the surface area at a rate of 0.005 km$^{2}$ a$^{-1}$ and the geodetic mass balance was $-$0.53 $\pm$ 0.11 m w.e. a$^{-1}$ for the period. Climatic variations over the last decade showed a pronounced increase in summer temperatures. The warmer conditions probably explain the glaciers mass loss observed in the Hulugou Basin.

• Journal of Earth System Science

Current Issue
Volume 128 | Issue 8
December 2019

• Editorial Note on Continuous Article Publication

Posted on July 25, 2019