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Assessment of an Evapotranspiration Deficit Drought Index in Relation to Impacts on Ecosystems

Abstract

Ecosystems have increasingly been subject to the challenge of heavy drought under global warming. To quantitatively evaluate the impacts of drought on ecosystems, it is necessary to develop a drought index that can sensitively depict the response of vegetation to drought evolution at a biological time scale. For the ability of direct connection between climate and ecosystem by deficit of evapotranspiration, in the present study, a drought index was defined based on standardized evapotranspiration deficit (SEDI), according to the difference between actual and potential evapotranspiration, to meet the need for highlighting drought impacts on ecological processes. Comparisons with traditional indices show that SEDI can reasonably detect droughts and climatic dry and wet transitions, especially at a monthly time scale, and can also regenerate long-term trends. Moreover, SEDI can more sensitively capture the biological changes of ecosystems in response to the dynamics of drought intensity, compared with the indices of precipitation and temperature. SEDI is more practical than the precipitation and temperature indices to highlight signals of biological effects in climate droughts. Hence, it has potential for use in assessments of climate change and its impact on ecosystems.

摘要

在全球变暖背景下生态系统越来越多地遭受到严重干旱的影响。为了量化干旱对生态系统的影响, 迫切需要发展一个包含生物学过程, 能够灵敏地描述植被响应干旱演变过程的干旱指数。由于蒸散差直接联系气候和生态系统过程, 因此本文基于实际和潜在蒸散的差值, 定义了一个标准化蒸散差干旱指数(SEDI)用于评估干旱对生态过程的影响。通过与传统干旱指数对比评估, 结果表明SEDI能合理地检测到月尺度的干旱和气候干湿演变, 且能重现气候的长期变化趋势。较之基于降水和温度的干旱指数, SEDI能更灵敏地反映生态系统对干旱强度变化的响应。SEDI相较降水和温度指数能突出气候干旱演变过程中的植被效应及植被对干旱强度变化的响应。因此, SEDI适用于评估气候变化及其对生态系统的影响评估。

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Acknowledgments

This study was jointly sponsored by the National Key R&D Program of China (Grant No. 2018YFA0606002), the National Natural Science Foundation of China (Grant Nos. 41575087 and 41875082), the Jiangsu Collaborative Innovation Center for Climate Change, and the UK-China Research & Innovation Partnership Fund through the Met Office Climate Science for Service Partnership (CSSP) China as part of the Newton Fund.

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Correspondence to Mingxing Li.

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Article Highlights

• SEDI is a drought index based on the difference between actual and potential evapotranspiration and effectively links climate and ecosystem processes.

• SEDI can detect droughts and climatic dry and wet transitions, especially at a monthly time scale, and also regenerate long-term climate trends.

• SEDI is better at capturing the biological response of ecosystems to drought evolution compared with the indices of precipitation and temperature.

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Zhang, X., Li, M., Ma, Z. et al. Assessment of an Evapotranspiration Deficit Drought Index in Relation to Impacts on Ecosystems. Adv. Atmos. Sci. 36, 1273–1287 (2019). https://doi.org/10.1007/s00376-019-9061-6

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  • DOI: https://doi.org/10.1007/s00376-019-9061-6

Key words

  • evapotranspiration
  • drought index
  • vegetation ecosystem
  • leaf area index
  • climate change

关键词

  • 蒸散
  • 干旱指数
  • 植被生态系统
  • 叶面积指数
  • 气候变化