气候变化领域集成服务门户(CCPortal): The aridity Index under global warming

CCPortal

DOI	10.1088/1748-9326/ab5046
	The aridity Index under global warming
	Greve P.; Roderick M.L.; Ukkola A.M.; Wada Y.
发表日期	2019
ISSN	17489318
卷号	14 期号:12
英文摘要	Aridity is a complex concept that ideally requires a comprehensive assessment of hydroclimatological and hydroecological variables to fully understand anticipated changes. A widely used (offline) impact model to assess projected changes in aridity is the aridity index (AI) (defined as the ratio of potential evaporation to precipitation), summarizing the aridity concept into a single number. Based on the AI, it was shown that aridity will generally increase under conditions of increased CO2 and associated global warming. However, assessing the same climate model output directly suggests a more nuanced response of aridity to global warming, raising the question if the AI provides a good representation of the complex nature of anticipated aridity changes. By systematically comparing projections of the AI against projections for various hydroclimatological and ecohydrological variables, we show that the AI generally provides a rather poor proxy for projected aridity conditions. Direct climate model output is shown to contradict signals of increasing aridity obtained from the AI in at least half of the global land area with robust change. We further show that part of this discrepancy can be related to the parameterization of potential evaporation. Especially the most commonly used potential evaporation model likely leads to an overestimation of future aridity due to incorrect assumptions under increasing atmospheric CO2. Our results show that AI-based approaches do not correctly communicate changes projected by the fully coupled climate models. The solution is to directly analyse the model outputs rather than use a separate offline impact model. We thus urge for a direct and joint assessment of climate model output when assessing future aridity changes rather than using simple index-based impact models that use climate model output as input and are potentially subject to significant biases. © 2019 The Author(s). Published by IOP Publishing Ltd.
英文关键词	aridity; climate change; vegetation; water availability
语种	英语
scopus关键词	Carbon dioxide; Climate change; Evaporation; Global warming; Vegetation; aridity; Aridity index; Complex nature; Comprehensive assessment; Increasing aridities; Model outputs; Potential evaporation; Water availability; Climate models; aridity; carbon dioxide; climate change; climate modeling; hydrometeorology; index method; precipitation (climatology); vegetation cover; water availability
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154326
作者单位	International Institute for Applied Systems Analysis, Water Program, Laxenburg, Austria; Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia; Australian Research Council Centre of Excellence for Climate Extremes, Canberra, ACT, Australia
推荐引用方式 GB/T 7714	Greve P.,Roderick M.L.,Ukkola A.M.,et al. The aridity Index under global warming[J],2019,14(12).
APA	Greve P.,Roderick M.L.,Ukkola A.M.,&Wada Y..(2019).The aridity Index under global warming.Environmental Research Letters,14(12).
MLA	Greve P.,et al."The aridity Index under global warming".Environmental Research Letters 14.12(2019).