祁连山气候变化特征及其对水资源的影响

祁连山作为我国重要的生态功能区、西北地区重要的生态安全屏障和河流产流区,是气候变化敏感区和生态环境脆弱区,其生态环境对西北地区经济发展起着重要作用。本研究利用祁连山区气温和降水观测数据、MOD10A2积雪产品以及石羊河、黑河和疏勒河流量资料,系统分析了1961—2020年祁连山区的气候变化特征,以及在气候变暖背景下,气候变化对祁连山区水资源的影响。结果表明: 1961—2020年,祁连山区平均气温呈显著上升趋势,升温速率达0.39 ℃·(10 a)^-1,西段升温速率最大,中、东段次之,冬季升温趋势最显著,春季最小;祁连山区平均气温在1997年发生突变。祁连山区年降水量总体呈波动增加趋势[10 mm·(10 a)^-1],中段增加最明显,2004年以来祁连山区处于多雨时期,气候呈暖湿化趋势;四季降水量均呈增加趋势,夏季降水增加对年降水贡献最大;年降水以年际尺度变化为主,2.8年的年际尺度贡献率高达64.3%。祁连山积雪面积受气温和降雪影响明显,与夏季气温存在负相关,与降雪量存在正相关;2016—2020年,祁连山增温趋缓、降雪增多,积雪面积呈增加趋势。2000年以来,祁连山升温加剧,降水增多,冰雪融水增加,石羊河、黑河和疏勒河出山径流均呈增加趋势。研究结果对祁连山区生态文明建设和应对气候变化具有重要意义。

Characteristics of climate change and its impacts on water resources in Qilian Mountains,China

Qilian Mountains, is an important ecological function area, an important ecological security barrier, the river runoff region in Northwest China, as well as a sensitive area to global climate change and fragile area of ecological environment. The ecological environment in this area played an important role in the economic development of Northwest China. Based on the observation data of temperature and precipitation in Qilian Mountains, MOD10A2 snow products and the flow data of Shiyang River, Heihe River and Shule River, we systematically analyzed the characteristics of climate change from 1961 to 2020, and the impacts of climate change on water resources under the scenario of climate warming. The results showed that, from 1961 to 2020, the annual average temperature increased significantly, with the rate reaching 0.39 ℃·(10 a)^-1. The warming rate was the highest in the western part of Qilian Mountains, followed by the middle and eastern regions. The warming trend was the strongest in winter and the lowest in spring. The average temperature changed abruptly in 1997. The annual average precipitation increased with flucturation, with a rate of 10 mm·(10 a)^-1, which increased most obviously in the middle of Qilian Mountains. After 2004, it entered a rainy period, with a warm and humid trend. The precipitation in the four seasons showed an increasing trend and the increase of precipitation in summer contributed the most to the annual precipitation. Annual precipitation was dominated by interannual scale change, and the contribution rate of 2.8-year was approximately 64.3%. The snow cover of Qilian Mountains was obviously affected by temperature and snowfall, which was negatively correlated with summer temperature and positively correlated with snowfall. From 2016 to 2020, the temperature increase had slowed down in Qilian Mountains, the snowfall had increased, and the snow cover tended to increase. After 2000, the temperature and precipitation increased more obviously, the meltwater from glacier and snow increased, the mountainous runoff of Shiyang River, Heihe River and Shule River had an increasing trend. Our findings are of great significance to the construction of ecological civilization and coping with climate change in Qilian Mountains.