Rapid increase of potential evapotranspiration weakens the effect of precipitation on aridity in global drylands. (March 2021)

• Record Type: Journal Article
• Authors: Pan, Ning; Wang, Shuai; Liu, Yanxu; Li, Yan; Xue, Feng; Wei, Fangli; Yu, Haipeng; Fu, Bojie
• Is Part Of: Journal of arid environments. Volume 186(2021)
• Publication Date: 2021-03
• Subjects: Aridity index -- Dryland -- Climate reversal -- Temporal contribution -- Potential evapotranspiration; Arid regions ecology -- Periodicals; Arid regions -- Periodicals; Écologie des régions arides -- Périodiques; Régions arides -- Périodiques; 577.54
• DOI: 10.1016/j.jaridenv.2020.104414
• Languages: English
• ISSNs: 0140-1963

Abstract

Abstract: Drylands are of great significance on terrestrial ecosystems and economic development, while being sensitive to climate changes and human activities. How global drylands extent and climate changed is not clear, and the dominant factor is the dispute over enhanced air evaporative demand and insufficient precipitation. This study attempted to fill this gap by exploring the trends in dryland areas, aridity index (AI), precipitation (P), and potential evapotranspiration (PET), and quantifying the temporal contributions of P and PET to AI. The results showed that the total dryland area shrunk 0.71 × 10 6 km 2 during 1901–2017 with reversed trend of shrinking to expanding. Precipitation dominates aridity in 88% of drylands, except for some regions in Europe and East Asia. With global warming, the relative contribution of PET to aridity in drylands increased significantly with a rate of 0.07% per year. The effect of PET exceeded that of P in 1966, which was the reason for the trend reversals of average AI. Highlights: The current dryland area is smaller than that in the early 20th century. Global drylands experienced a reversed trend from wetting to drying. Precipitation dominated the change in aridity index in 88% of drylands. The effects of potential evapotranspiration on aridity index increased by 0.07% per year.