乌鲁木齐河源1号冰川积累区表面雪层演化成冰过程的观测研究

Observation and Study of the Snow to Ice Transformation in the Accumulation Zone of Glacier No.1 at the Headwaters of rümqi River

根据天山乌鲁木齐河源1号冰川积累区海拔4 130 m处28个月,每周1次的连续雪层剖面观测,分析研究了雪层厚度、雪层中的污化层、冰片和各种粒雪随时间的演变过程.结果表明:雪层中各种要素的演变受水热条件的影响而呈现明显的季节特征.根据温度、融水渗浸程度及雪层剖面的变化程度,我们将其分成冬季稳定期、夏季剧变期和春秋季波动期分别进行了分析.此外,还对雪层年限与年成冰量等进行了专门讨论.

Physical process of snow to ice transformation is one of important research objects in Glaciology. However, most previous studies on the Glacier No. 1 focused mainly on properties of snow profiles, rather than the process, because of lack of long-term field observation. The currently launched PGPI （the Program for Glacier Process Investigation） provides a unique opportunity to observe this evolution process and to trace every change in snow-firn pack at PGPI observation and experimental site on the Glacier No. 1, which in turn made a great contribute to PGPI. During PGPI field campaigns from 2002 through to 2004, about 110 snow/firn stratigraphy profiles （in weekly interval） were obtained at PGPI site （4 130 m a. s. 1. , in the percolation zone）, on which various physical measurements and observations have been made simultaneously, as a result, the evolution process can be analyzed in detail. Particular effort was contributed to those visible layers on snow-firn stratigraphy, such as different sized firn, dust layers, ice slices, etc. , by tracing their evolution processes. The results have reveled enormous details of these processes over the twoyear period. It is found that percolation of meltwater has a definitive impact on the transformation process. Ice formation process in a year can be divided into four periods depending on features of the process： winter steady period, spring fluctuation periods, summer intense period and autumn fluctuation period. Different periods have been discussed respectively in this paper.