1960—2019年黄河源区气候变化时空规律研究

Spatio-temporal characteristics of climate change in the Yellow River source area from 1960 to 2019

黄河源区是气候变化敏感区及生态环境脆弱区,也是黄河的主要产流区,其气候变化问题备受关注。利用黄河源区均一化气温和降水观测数据,系统分析了近60 a黄河源区平均气候与极端气候事件的变化特征。结果表明:1960—2019年黄河源区年平均气温、平均最高及最低气温表现出增温趋势的一致性,且源区东部增温幅度高于西部;黄河源区年均气温在2000年前后发生突变转折,转折后升温速率达0.61℃·(10a)^(-1),高于1960—2019年的增温率0.37℃·(10a)^(-1)。1960—2019年黄河源区年降水量总体呈微弱增加趋势[7.6 mm·(10a)^(-1)],2003年后进入降水偏多阶段,近10 a(2010—2019年)源区平均年降水量达到610 mm;春、夏、冬季降水增多,秋季降水减少;其中源区东部夏、秋季降水减少明显,阶段性干旱风险加剧。近10 a源区平均气温、降水量均为60 a来最高值,总体处于最暖湿阶段。受持续暖湿化影响,1960—2019年黄河源区平均极端气温阈值呈显著的增大趋势,而霜冻日数减少;年最大3日降水量和强降水日数增多,降水强度增大,其中尤以夏季最为显著,对源区生态保护和水资源利用乃至黄河全流域高质量发展均可能带来风险挑战。

As a fragile ecological environment,the source region of the Yellow River(SRYR)is sensitive to climate change.It is also the primary region generating runoff in the Yellow River Basin.The issue of climate change in the SRYR has attracted substantial attention.This study systematically re-examined changes in the average climate and extreme climate events in the SRYR over the past 60 years using homogenized temperature and precipitation data.From 1960 to 2019,the annual average temperature and average maximum and minimum temperatures of the SRYR increased consistently,with the most substantial warming in the eastern part of the source area.After the turning point in 2000,the warming rate reached 0.61℃·(10a)^(-1),which was significantly higher than that for the period of 1960-2019[0.37℃·(10a)^(-1)].From 1960 to 2019,the annual precipitation in the SRYR generally showed a slight increase,at a rate of 7.6 mm·(10a)^(-1).After 2003,it entered a stage of more precipitation,with the regional average annual rainfall reaching 610 mm during 2010-2019.Spring,summer,and winter precipitation increased over the past 60 years,while autumn precipitation decreased.Meanwhile,summer and autumn precipitation in the eastern part of the source area decreased substantially,leading to an increased risk of staged drought.Of the last 60 years,the average temperature and precipitation in the source area were highest in the past 10 years,and the research region was generally at its warmest and wettest stage simultaneously.Affected by the background of warming and wetting,from 1960 to 2019,the average extreme temperature threshold of the SRYR increased significantly,while the number of days with frost decreased,the annual maximum three days of precipitation and the number of heavy precipitation days increased,and precipitation intensity strengthened,most notably in summer.Thus,all of these changes possibly bring series of risks and challenges to ecological protection and utilization of water resources in the SRYR and to the development of the entire Yellow River Basin.