The State Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou 730000, China; Qilian Mountain Glacier and Ecological Environment Research Station, Lanzhou 730000, China.
The State Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou 730000, China; Qilian Mountain Glacier and Ecological Environment Research Station, Lanzhou 730000, China.
Sci Total Environ. 2014 Sep 15;493:930-42. doi: 10.1016/j.scitotenv.2014.06.025. Epub 2014 Jul 7.
This work discusses the temporal variation of various physicochemical species in the meltwater runoff of Laohugou Glacier No. 12 (4260 ma.s.l.) in central Asia, and their correlation with dust particles, based on a two-year field observation in summer 2012 and 2013, mainly focusing on dust concentration and size distribution, meltwater chemistry, particles SEM-EDX analysis in the meltwater, and MODIS atmospheric optical depth fields around the Qilian Mountains in central Asia. We find that, the volume-size distribution of dust particles in the meltwater is mainly composed of three parts, which includes fine aerosol particles (with diameter of 03.0 μm, mainly PM 2.5), atmospheric dust (with diameter of 3.020 μm), and local dust particles (20~100 μm), respectively. Comparison of dust particles in the snowpack and meltwater runoff indicates that, large part of dust particles in the meltwater may have originated from atmospheric dust deposition to the snow and ice on the glacier, and transported into the meltwater runoff. Moreover, temporal variation of dust and major ions (especially crustal species) is very similar with each other, showing great influence of dust particles to the chemical constituents of the glacier meltwater. SPM and TDS implied significant influences of dust to the physical characteristics of the glacier meltwater. Results showed that, accelerated glacier melting may affect physicochemical characteristics of the meltwater at an alpine basin under global warming. MODIS atmospheric optical depth (AOD) fields derived using the Deep Blue algorithm, showed great influence of regional dust transportation over western Qilian Mountains in springtime. SEM-EDX analysis shows that dust particles in the glacier meltwater contain Si-, Al-, Ca-, K-, and Fe-rich materials, such as quartz, albite, aluminate, and fly ash, similar to that deposited in snowpack. These results showed great and even currently underestimated influences of atmospheric dust deposition to glacier meltwater physicochemistry at an alpine basin in central Asia.
本研究讨论了中亚地区老沟 12 号冰川（海拔 4260 米）融水中各种物理化学物质的时间变化及其与粉尘颗粒的相关性。研究基于 2012 年和 2013 年夏季的两年野外观测，主要关注粉尘浓度和粒径分布、融水化学、融水中颗粒的 SEM-EDX 分析以及中亚祁连山区周围的 MODIS 大气光学深度场。研究发现，融水中粉尘颗粒的体积-粒径分布主要由三部分组成，分别为细气溶胶颗粒（直径 03.0μm，主要为 PM2.5）、大气粉尘（直径 3.020μm）和局地粉尘颗粒（20~100μm）。融雪中和融水中的粉尘颗粒对比表明，融水中的大部分粉尘颗粒可能来自大气降尘在冰川上的冰雪中的沉积，并被搬运进入融水中。此外，粉尘和主要离子（尤其是地壳物质）的时间变化非常相似，表明粉尘对冰川融水化学组成有很大影响。SSP 和 TDS 表明粉尘对冰川融水的物理性质有显著影响。研究结果表明，在全球变暖背景下，加速的冰川融化可能会影响高山盆地下的融水理化特征。利用 Deep Blue 算法反演得到的 MODIS 大气光学深度（AOD）场表明，春季祁连山西部地区的区域粉尘输送对该地区有很大影响。SEM-EDX 分析表明，冰川融水中的粉尘颗粒含有富 Si、Al、Ca、K 和 Fe 的物质，如石英、钠长石、铝酸盐和粉煤灰，与在积雪中沉积的物质相似。这些结果表明，大气降尘对中亚高山盆地下冰川融水理化性质的影响巨大，甚至可能被低估。
