Five decades of shrinkage of July 1st glacier, Qilian Shan, China

Abstract

A survey of July 1st glacier, Qilian Shan, China, was carried out in 2002. Previously, the glacier’s boundary had been recorded in 1956, and further research had been carried out in the mid- 1970s and 1980s. Our survey reveals that area shrinkage and surface lowering have accelerated in the past 15 years. Surface elevation changes can result from changes in accumulation, surface melting and emergence velocity. The contributions of these elements to surface lowering are evaluated at the lower part of the glacier from observations of surface velocity, ice thickness and precipitation, and from temperature data near the glacier. Apart from the effect of glacier ice redistribution, our analysis reveals quantitatively that the recent accelerated glacier shrinkage has been caused by increasing temperature. Furthermore, it is established that meltwater discharge from the glacier in the past 17 years has increased due to glacier shrinkage, by about 50% over that from 1975 to 1985.

Rapid shrinking of glaciers in the Middle Qilian Mountain region of Northwest China during the last ∼50 years

“…Moreover, the linear trend analysis indicated that the average increase rate of winter precipitation (0.28 mm/10a) was less, which cannot make up the mass loss of glaciers, resulting in the accelerated melting. It is consistent with the research results of the Qiyi glacier of this region (Sakai et al, 2006). Although the annual precipitation increased slightly from 1960 to 2005, generally increasing summer temperature leads to significant glacier melt, which seems to be the most significant factor for recent glacier shrinkage in the Middle Qilian Mountain region.…”

A shallow ice core re-drilled on the Dunde Ice Cap, western China: recent changes in the Asian high mountains

“…The net accumulation decrease caused by melt water runoff should result in considerable mass loss of the ice cap. A glacial mass balance survey on the July 1st Glacier in the Qilian Mountains, located 70 km northeast of the ice cap, revealed that the glacier (both length and surface level) has decreased continuously since the 1950s, and its shrinkage was particularly significant after the late 1980s (Sakai et al 2006). The study concluded that increasing air temperature caused the recent accelerated shrinkage of the glacier.…”

Temporal Changes in Elevation of the Debris-Covered Ablation Area of Khumbu Glacier in the Nepal Himalaya since 1978

“…We acquired flow data at the upper and lower boundary of the continuity equation. The flow velocity averaged over the depth of the glacier was set as 80% of the mean surface velocity according to Paterson (1994) and Sakai et al (2006). Other parameters are considered in the following section.…”