利用冰川编目最新数据资料,计算恒河-雅鲁藏布江冰川平均高度(Hme)与测量雪线(ELAb)之间的回归方程,发现冰川系统越大。样本数越多,则相关性越好,从而建立大系统的回归方程计算系统内所有冰川样点的计算雪线高度(ELAhc).对所求得的ELAhc采用10'×10'的格网覆盖区域,对格网内样点的经纬度和计算雪线高度进行算术平均,用Kriging插值生成一定间隔的雪线分布图。即雪线高度场.把所得结果与该区域已有研究对比,发现它除具有共同的基本规律外,还更能体现出西藏南部雪线场的详尽分布规律,如全流域从下游向上游按照平均雪线高度的大小可以分为4个区,不伺区域的雪线分布反映了影响区域雪线分布的主导因素.此方法可应用于其它已进行冰川编目的地区,也可建立不同尺度的温度场、积累场、降水场等冰川特征值场.
On the basis of the glacier inventory of China, the calculated snow line(ELAhc) can be obtained, based on the linear relationship between ELAh and Hme, It is revealed that the more number of the data of ELAh, the more sound linear relationship between ELAh and Hme, in a glacier system is. In order to minimize the influence of topographical snowqine and other uncertain error, a method is adopted that to overlay the data points with a graticule mesh of 10' × 10', and then to calctilate arithmetic average values of all the data points" lon gitude, latitude and ELAhc in every square, utilizing such software as ArcGIS 9, etc. Then an ELAhc distribution map, namely, the field of equilibrium line attitude, with an interval of 100 m, is produced by ordinary Kriging interpolation. In this paper it is found that. 1) The result in the recent equilibrium line attitude field is different from the previous ones from others, and shows more detail of glacier distribution in the southern Tibet glacier system, besides some common understanding; 2) The field gradient of ELAhc is greater in the south than in the north of the GangazYarlung Zangbo Rivers system, with 5 m · km^-1 in the south and 0.5m · km^-1 in the north. Furthermore, the distribution of ELAho is more complicated and the high ELAhc values and low ELAhc values appear alternative; 3) In this region the influence of precipitation on the distribution of ELAhc is more evident than the influence of temperature, because precipitation decreases westwards, and the ELAhc increases westwards, with a gradient of ELAhc varying from 2.5 m · km^-1 to 4-6 m · km^-1 from east to west.