Journal of Arid Meteorology

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Interdecadal Characteristics of Global Dry-wet Variation Based on Three Indexes

CHENG Shanjun, LIANG Sujie   

  1. Tianjin Climate Center, Tianjin 300074, China
  • Online:2018-04-30 Published:2018-04-30

基于3种指数的全球干湿变化年代际特征

程善俊梁苏洁   

  1. 天津市气候中心,天津 300074
  • 作者简介:程善俊(1990— ),男,博士,工程师,主要从事干旱化机理研究. E-mail:chengshj08@lzu.edu.cn。
  • 基金资助:

    公益性行业(气象)科研重大专项(GYHY201506001-1)、公益性行业(气象)科研专项(GYHY201506019)和天津市气象局课题(201628bsjj01)共同资助

Abstract:

By comparison, three dry-wet indexes of AI, PDSI and soil moisture can describe consistently the spatial and temporal distribution characteristics of global dry-wet variation. And on this basis the period and long-term variation trend of dry-wet variation in the globe and different climatic regions were investigated, and the interdecadal variation of dry-wet indexes and its mechanism were explored. The results show that three dry-wet indexes presented an obvious decreasing trend in the globe in the past 67 years, which indicated that the globe was becoming drier. The drying trend was most significant in sub-humid region, followed by hyper-arid, humid, and semi-arid regions, while in arid region it appeared a wetting trend. The main period of global dry-wet change was quasi-20 years, but in different climatic regions it was different. And the main period in arid, semi-arid and humid regions was quasi-20 years, while in hyper-arid and sub-humid regions it was quasi-30 years. The potential evapotranspiration increased significantly in the globe during 1948-2014, which caused the global drying, but the period with quasi-20 years of global dry-wet change was dominated by the interdecadal variation of precipitation.

Key words: dry-wet index, drying, climatic regions, interdecadal variation

摘要:

通过对比AI指数、PDSI指数和土壤湿度的变化发现,3种指数能够较为一致地反映全球干湿变化的时空分布特征,在此基础上,研究了全球及不同气候区干湿变化的长期变化趋势和周期信号,并重点分析干湿指数的年代际演变及其变化机制。结果表明:近67 a来,全球整体呈现干旱化趋势,其中半湿润区干旱化最为显著,其次为极端干旱区、湿润区和半干旱区,而干旱区表现为变湿趋势;全球干湿变化存在准20 a的显著周期信号,但不同气候区的主要变化周期存在差异,其中干旱区、半干旱区和湿润区的主周期为准20 a,而极端干旱区和半湿润区为准30 a;潜在蒸散量的显著增加趋势是导致全球干旱化的主要原因,而全球干湿变化的准20 a周期主要由降水振荡所控制。

关键词: 干湿指数, 干旱化, 气候区, 年代际变化

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