西藏班戈错近50年来的湖面变化

本文根据大量地形图、遥感图像或遥感数据、连续29个月的水位观测记录、三次水深测量和2003年5 月26日的湖水位高程测量等资料,勾绘了班戈错近50年来的湖岸线变迁和湖面高程变化曲线图。研究表明,自1959 年至2003年9月的近50年间班戈错湖面总体上升,但其间经历了先降后升再略有下降的过程,即自1959年至1973年或稍晚,班戈错一直收缩、湖面下降了0．25 m;自1973年或稍晚至2001年秋,湖面总体上升,其幅度可达1．75 m;其后,湖面又略有下降。班戈错湖面变化的原因难以用其面积较小的流域本身的气温与降水的变化来解释,只能归结为与其有水力联系的母湖色林错流域自1973年起气温的持续上升所引起的主要补给河流扎加藏布源区唐古拉山与巴汝藏布和申扎藏布源区申扎杰岗山的现代冰川的融水释放水量增大使色林错水位上升,因色林错与班戈错之间有一定的水力联系而引起班戈错水位上升。

The Denivellation of Bankog Co in the Past 50 Years,Tibet

According to the relief maps, air-screened, remote sensing photos, continuous observation and survey of 29 months, three measurements of the lake depth, as well as data of the lake elevation in May 26, 2003, this paper presents a sketch map of the level variation of Bankog Co in the past 50 years. It shows that the lake level has a rise trend in general from 1959 to September, 2003. However, it underwent a procedure of descent, ascent, and slight descent, namely, from 1963 to 1973 or late, Bankog Co continued to contract and the lake level had a 0. 25 m-full, from 1973 or late to late 2001, the lake level generally rose with an extent of 1. 75 m. Subsequently, the level slightly descended. It is difficult to explain the variation of Bankog Co's water level with its air temperature and small drainage area. The reasons are mainly ascribed to the water level variation of Silin Co,to which Bankog Co connects. With continuous rise of air temperature from 1973, the water amount of melted ice from the Mts. Tanggula (source of the Za'gya Zangbo River) and the Mts. Xianzajiegang (source of the Bairo Zangbo and Xianza Zangbo Rivers) modern glacier, the main water source for Silin Co, has increased. Bankog Co has hydraulic relation with Silin Co. , which leads to the denivellation of Bankog Co.