Temperate ice layer found in the upper area of Jima Yangzong Glacier,the headstream of Yarlung Zangbo River

For the first time we investigate the basal thermal condition in the upper area of Jima Yangzong Glacier, the headstream of Yarlung Zangbo River, using ground-penetrating radar techniques. With common offset and common mid-point surveys we analyze the radar velocities in ice with respect to cold-temperate ice transition surface(0.1751 ± 0.0028 m ns^(-1)) and ice-bedrock interface(0.1657 ± 0.0033 m ns^(-1)), indicating a radar velocity of 0.1410 ± 0.0154 m ns^(-1) for the temperate ice layer(16.6 ± 1.8 m). We estimate that the temperate ice layer has a water content of around 6 % ± 4 %, suggesting that the Jima Yangzong Glacier, previously known as continental-type, now possibly becomes polythermal.

For the first time we investigate the basal thermal condition in the upper area of Jima Yangzong Glacier, the headstream of Yarlung Zangbo River, using ground-penetrating radar techniques. With common offset and common mid-point surveys we analyze the radar velocities in ice with respect to cold-temperate ice transi- tion surface （0.1751 0.0028 m ns-~） and ice-bedrock interface （0.1657 ＋ 0.0033 m ns-a）, indicating a radar velocity of 0.1410 4- 0.0154 m ns-1 for the temperate ice layer （16.6 ~ 1.8 m）. We estimate that the temperate ice layer has a water content of around 6 % 4- 4 %, suggesting that the Jima Yangzong Glacier, previously known as continental-type, now possibly becomes polythermal.