1961-2022 年河西走廊气温和降水量的时空变化特征

Spatiotemporal Variation Characteristics of Temperature and Precipitation in Hexi Corridor from 1961 to 2022

摘要:

利用 1961-2022 年甘肃河西走廊地区 17 个国家气象站的气温和降水量观测数据，采用集合经验模态分解（EEMD）、最小二乘法线性拟合方法研究该地区气温和降水的时空变化特征。结果表明，近 62 a 来河西走廊地区平均气温呈持续上升趋势，年平均气温倾向率为 0.36 ℃/10 a(P<0.01)，特别是 20 世纪 90 年代以后气温升高明显。年最高气温和最低气温也呈上升趋势，其中冬季升温趋势最为显著，增温率远高于其他三季。近 62 a 的年降水量总体呈增加趋势，四季降水量增加幅度为夏季＞秋季＞春季＞冬季，其中夏季降水量最多，对全年降水量的贡献最大。通过EEMD分析，发现年平均气温有明显的准 3 a 周期振荡，年降水有明显的准 2 a 周期振荡；与气温序列相比，降水序列中年代际尺度的变化和长期趋势的贡献明显要小。从空间分布来看，河西走廊中、东部增温明显高于西部，北部增温高于南部；东部降水量增加最多，其次为中部，西部最少，南部降水量增加大于北部。

Abstract:

Using temperature and precipitation observation data from 17 national meteorological stations in the Hexi Corridor region of Gansu Province from 1961 to 2022, this study employed ensemble empirical mode decomposition (EEMD) and the least squares linear fitting method to investigate the spatiotemporal variations in temperature and precipitation in this area. The results indicate that over the past 62 years, the average temperature in the Hexi Corridor has shown a continuous upward trend, with an annual average temperature increase rate of 0.36°C/10 years (P<0.01), particularly notable since the 1990s. Both the annual maximum and minimum temperatures also exhibit upward trends, with the most significant warming occurring in winter, which is substantially higher than the other three seasons. Over the same period, annual precipitation has generally increased, with seasonal precipitation rising in the order of summer > autumn > spring > winter, with summer contributing the most to the annual precipitation. EEMD analysis revealed a significant quasi-3-year periodic oscillation in the annual average temperature, while annual precipitation exhibited a significant quasi-2-year periodic oscillation. Compared to the temperature series, the decadal-scale changes and long-term trend contributions in the precipitation series were notably smaller. Spatially, the warming trend in the central and eastern parts of the Hexi Corridor was significantly higher than in the western part, and warming in the northern part was greater than in the southern part. Precipitation increased the most in the eastern part, followed by the central part, with the least increase observed in the western part. Additionally, precipitation increased more in the southern part compared to the northern part.