Feiteng Wang

Glacier area shrinkage in China and its climatic background during the past half century

Based on the glacier area variation records in the typical regions of China monitored by remote sensing, as well as the meteorological data of air temperature and precipitation from 139 stations and the 0°C isotherm height from 28 stations, the glacier area shrinkage in China and its climatic background in the past half century was discussed. The initial glacier area calculated in this study was 23,982 km2 in the 1960s/1970s, but the present area was only 21,893 km2 in the 2000s. The area-weighted shrinking rate of glacier was 10.1%, and the interpolated annual percentage of area changes (APAC) of glacier was 0.3% a−1 since 1960. The high APAC was found at the Ili River Basin and the Junggar Interior Basin around the Tianshan Mountains, the Ob River Basin around the Altay Mountains, the Hexi Interior Basin around the Qilian Mountains, etc. The retreat of glacier was affected by the climatic background, and the influence on glacier of the slight-increased precipitation was counteracted by the significant warming in summer.

Hydrochemical Characteristics and Solute Dynamics of Meltwater Runoff of Urumqi Glacier No.1, Eastern Tianshan, Northwest China

Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007. The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007, respectively. In the meltwater, the dominant anions were the bicarbonate and sulphate, and the dominant cation was calcium. The concentration of major cations were varied as c(Ca2+) > c(Mg2+) > c(K+) > c(Na+), while the order for the cations was c(HCO3−) > c(SO42−) > c(NO3−) > c(Cl−). The total dissolved solids (TDS) in meltwater had inverse relationships with the diurnal discharge. The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model. Furthermore, the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering, pyrite weathering and feldspar weathering in rocks, and Ca2+ and HCO3− were the dominant ions during the carbonate weathering process. Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 ton·km−2·yr−1 in 2006 and 2007, respectively.

Seasonal evolution of aerosol stratigraphy in Urumqi glacier No. 1 percolation zone, eastern Tien Shan, China

Abstract The processes involved in the evolution of vertical profiles of Mg2+, Ca2+ and microparticle concentrations, as well as their seasonal variation in surface snow, were studied by weekly sampling from September 2003 to September 2004 of a snow pit on Ürümqi glacier No. 1, eastern Tien Shan, China. The development of the microparticle and Mg2+ and Ca2+ stratigraphy in the snow pit is closely related to the physical development of the snow–firn pack. The sampling site is located at 4130 ma.s.l. in the percolation zone of the glacier, and in addition to the effects of sublimation and wind erosion, melting plays a crucial role in both the physical and chemical evolution processes. During the winter, soluble aerosol concentrations in the surface layers are altered slightly by sublimation and wind erosion, and the concentrations are further modified as the wet season begins in late April. In contrast, soluble aerosol stratigraphy in the deeper layers remains relatively unchanged through the winter. In early summer, as melting occurs in the upper part of the snow–firn pack, meltwater carries chemical species to different depths in the underlying snow–firn layers, such that at the end of the ablation season, all of the surface cations might be leached out from the upper layers. In addition, the possible source of calcium and magnesium is discussed in this paper.

Glacier volume calculation from ice-thickness data for mountain glaciers-A case study of Glacier No. 4 of Sigong River over Mt. Bogda, eastern Tianshan, central Asia

The determination of total glacial volume is important for the observation of climatic change and its consequences such as global sea-level rise. The tongue area of Glacier No. 4 of Sigong River over Mt. Bogda, eastern Tianshan was surveyed by ground-penetrating radar (GPR) and real time kinematic (RTK)-global positioning system (GPS) during the summer campaign 2009. In order to calculate the glacier volume, both co-kriging algorithm and estimation based on the theory of perfectly plastic material were employed. Results indicated that the ice-thickness distribution of the investigated glacier ranges from 0 to 105.0 m, with the mean thickness of 27.6 m in 2009. The corresponding ice volume was ∼0.076 km3 (∼0.068 km3 water equivalent). The bedrock topography shows more undulating than the glacier surface. The difference of the calculated ice volume in this study and the estimated value from the empirical formula is large. Therefore, it is urgent to validate the applicability of the existing empirical formula.

Characteristics of ionic concentration and d 18 O and their variability in dry-season and wet-season snow on Urumqi glacier No. 1, eastern Tien Shan, central Asia

Abstract To investigate the environmental and climatic significance of the ice-core records from the Tien Shan, central Asia, the characteristics of ionic concentration and oxygen isotopic ratio (δ18O) as well as their variability are assessed from surface-snow samples as well as old-snow samples collected year-round at weekly intervals from November 2002 to October 2005 on Ürümqi glacier No. 1, eastern Tien Shan. The results indicate that the δ18O in surface-snow samples is reversely coincident with air temperature and insignificantly affected by post-depositional processes. Ionic concentrations in the wet-season (1 November to 31 March) snow are overall higher than those in dry-season (1 April to 31 October) snow, while the variability of relative ionic composition between dry seasons is slightly less than that between wet seasons. During dry seasons, surface-snow chemistry was mostly controlled by the chemical content entrained in some sporadic precipitations. When precipitation is absent, the effect of all post-depositional processes together elevated the ionic concentrations in surface snow. During wet seasons, the snow chemistry is determined mainly by the input of aerosols entrained in precipitation and the elution process from percolation of meltwater.

The diagnostics of density distribution for inhomogeneous dense DT plasmas using fast protons

The density distribution of inhomogeneous dense deuterium-tritium plasmas in laser fusion is revealed by the energy loss of fast protons going through the plasma. In our simulation of a plasma density diagnostics, the fast protons used for the diagnostics may be generated in the laser-plasma interaction. Dividing a two-dimensional area into grids and knowing the initial and final energies of the protons, we can obtain a large linear and ill-posed equation set. for the densities of all grids, which is solved with the Tikhonov regularization method. We find that the accuracy of the set plan with four proton sources is better than those of the set plans with less than four proton sources. Also we have done the density reconstruction especially. for four proton sources with and without assuming circularly symmetrical density distribution, and find that the accuracy is better for the reconstruction assuming circular symmetry. The error is about 9% when no noise is added to the final energy for the reconstruction of four proton sources assuming circular symmetry. The accuracies for different random noises to final proton energies with four proton sources are also calculated.

Long-range terrestrial laser scanning measurements of summer andannual mass balances for Urumqi Glacier No. 1, eastern Tien Shan,China

The direct glaciological method typically provides in situ observations of annual or seasonal surface mass balance, but 10 can only be implemented through a succession of intensive in situ measurements of measuring networks of stakes and snow pits. This has contributed to glacier surface mass-balance measurements being sparse and often discontinuous in the Tien Shan. Nevertheless, long-term glacier mass-balance measurements are the basis for understanding climate–glacier interactions and projecting future water availability for glacierized catchments in the Tien Shan. Riegl VZ-6000 long-range terrestrial laser scanning (TLS), typically using class 3B laser beams, is exceptionally well suited for measuring snowy and icy terrain in repeated 15 glacier mapping, and subsequently annual and seasonal geodetic mass balance can be determined. This paper introduces the applied TLS for monitoring summer and annual surface elevation and geodetic mass changes of Urumqi Glacier No.1 (UG1) as well as delineating accurate glacier boundaries for two consecutive years (2015-17), and discusses the potential of such technology in glaciological applications. Three-dimensional changes of ice and firn/snow bodies and the corresponding densities were considered for the volume-to-mass conversion. UG1 showed pronounced thinning and mass loss for the four investigated periods; glacier-wide 20 geodetic mass balance in the mass-balance year 2015-16 was slightly more negative than in 2016-17. The majority of TLS-derived geodetic elevation changes at individual stakes were slightly positive, but showed a close correlation with the glaciological elevation changes (changes in exposed stake height) of individual stakes (R ≥ 0.90). Statistical comparison shows that agreement between the glaciological and geodetic mass balances can be considered satisfying, indicating that the TLS system yields accurate results and has the potential to monitor remote and inaccessible glacier areas where no glaciological measurements are available. 25

Applicability of an ultra-long-range terrestrial laser scanner to monitor the mass balance of Muz Taw Glacier, Sawir Mountains, China

Glacier mass balance is a key component of glacier monitoring programs. Information on the mass balance of Sawir Mountains is poor due to a dearth of in-situ measurements. This paper introduces the applicability of an ultra-long-range terrestrial laser scanner (TLS) to monitor the mass balance of Muz Taw Glacier, Sawir Mountains, China. The Riegl VZ ® -6000 TLS is exceptionally well-suited for measuring snowy and icy terrain. Here, we use TLS to create repeated high spatiotemporal resolution DEMs, focusing on the annual mass balance (June 2, 2015 to July 25, 2016). According to TLS-derived high spatial resolution point clouds, the front variation (glacier retreat) of Muz Taw Glacier was 9.3 m. The mean geodetic elevation change was 4.55 m at the ablation area. By comparing with glaciological measurements, the glaciological elevation change of individual stakes and the TLS-derived geodetic elevation change of corresponding points matched closely, and the calculated balance was −3.864±0.378 m w.e.. This data indicates that TLS provides accurate results and is therefore suitable to monitor mass balance evolution of Muz Taw Glacier.

Heavy metal-polluted aerosols collected at a rural site, Northwest China

Daily samples of aerosol (n=27) were collected from September 21st to October 4th, 2013 in Fukang (44.17°N, 88.45°E, 475 m a.s.l.), Xinjiang, Northwest China. The enrichment factors (EFc) of selected 49 elements showed that the aerosols had extremely high concentrations of heavy metals, probably indicating their anthropogenic origins. Morphology of individual aerosol particles was determined by scanning electron microscopy and energy-dispersive X-ray microanalysis. Based on morphology and elemental composition, the particles were clustered into three dominant types: (I) crustal originated particles: Si/Al-rich particles (36%) and Si/Fe-rich particles (24%); (II) mixed source particles; and (III) pollution derived particles: Pb-rich particles (10%). The backward trajectories were calculated using the HYSPLIT model, and the results indicated the different anthropogenic sources for heavy metals in Fukang aerosols. Air mass from north was identified as the most polluted source when compared to south and west.

Monitoring of drought in qinghai province by using standardized precipitation index (spi)

1State Key Laboratory of Cryospheric Sciences/Tian Shan Glaciological Station, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, 730000, China 2University of Khartoum, Faculty of Forestry, Department of Forest Protection and Conservation, Code 13314, Shambat, Sudan 3Northwest Normal University, College of Geography and Environmental Science, Anning Road, Lanzhou 730000, P. R. China 4Division of Hydrology Water-Land Resources, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, 730000, China