新疆阿尔泰山额尔齐斯河源区不同降水观测方法对比分析及1980-2015年降水变化研究

合理评估不同降水观测仪器的精度是评价区域降水变化的前提。基于阿尔泰山额尔齐斯河源区库威水文站ø20 cm标准雨量筒的人工降水观测和库威积雪站T-200b的自动降水观测，对比分析了T-200b和ø20 cm标准雨量筒的观测精度，在此基础上，基于1980-2015年库威水文站的降水观测，分析了阿尔泰山额尔齐斯河源区的降水变化。结果表明：两种方法观测的日降水、月降水和年降水量均具有良好的相关性；两种方法观测液态降水相关性要明显优于固态降水；随着降雨强度的增加，两种观测方法的相关性显著增强。总体上，T-200b观测的降水量较ø20 cm标准雨量筒偏高。1980-2015年间额尔齐斯河源区的年降水量以2005年为转折点呈现"先增加后减小"的变化趋势，且冷季（11月至次年3月）的降水增加显著，冷季的降水占年降水量的比例呈现逐渐增加的变化趋势。降水和融雪过程的变化已导致春季融雪水文过程发生改变，进一步合理评估地表可利用水资源的年内重分配是该地区水安全的重要保障。

Comparison of precipitation observed by T-200 b and standard rain gauge and precipitation change during 1980-2015 in the headwaters of Irtysh River,Chinese Altai Mountains

Assessing the observation accuracy of rainfall gauge is the first step to investigate the regional and global precipitation change. The comparison and analysis between T-200b rainfall gauge and ø20 cm standard rainfall gauge of China was carried out based on precipitation observations from 2011 to 2016 at Kuwei National Hydrological Station and Kuwei Snow Station in the headwaters of the Irtysh River basin, Chinese Altai Mountains. Then, the precipitation dataset during 1980-2015 from Kuwei National Hydrological Station was utilized to analyze the long-term precipitation change in this region. Comparison indicated that:(1) There are good relationships among daily, monthly and annual precipitations observed by the two methods; (2) The relationship for rainfall observed by the two methods is better than that for solid precipitation; (3) The relationship of precipitation observed by the two methods would get better with increasing rainfall intensity. Generally, the precipitation observed by T-200b is more than that by ø20 cm standard rainfall gauge. The annual precipitation in the headwaters of the Irtysh River had increased from 1980 to 2005, and then had slightly declined. Precipitation in cold season from November to March had significantly increased during 1980-2015, and the proportion of precipitation in cold season to annual precipitation had increased gradually.