Structural analysis of thermokarst lake ice in Beiluhe Basin, Qinghai–Tibet Plateau

The high altitude and cold climate of the Qinghai–Tibet Plateau (QTP) means that rivers and lakes are covered by ice for 6–7 months of the year. The ice cover is a major influence on environmental and ecological conditions, since it alters the heat and energy exchange with local atmosphere, as well as determines the design and construction of civil buildings. However, research on these ice covers has not been conducted previously. For the first time, the present work focuses on in-situ observations of ice growth and decay, and the inner structural analysis of ice samples from a thermokarst lake, Beiluhe basin, in the central plateau. Ice was sampled on two occasions during fast growth and slow growth periods. Ice crystals, densities and gas bubbles were investigated and classified into ice types. Vertical profiles of the ice crystal type, crystal size, fabrics, gas bubble shape and size, gas content, as well as ice density were determined. The formation mechanism was discussed based on QTP meteorology and stratigraphy.