Future changes of global potential evapotranspiration simulated from CMIP5 to CMIP6 models

ABSTRACT

This research evaluated the ability of different coupled climate models to simulate the historical variability of potential evapotranspiration (PET) for the time period 1979–2017 in phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5 and CMIP6, respectively). Their projected future changes of PET under two emission scenarios for the 21st century were also compared. Results show that PET has an increasing trend of 0.2–0.6 mm d⁻¹/50 yr over most land surfaces and that there are clear regional differences. The future value of PET is higher in the CMIP6 multi-model simulations than in the CMIP5 ones under the same emissions scenario, possibly because CMIP6 models simulate stronger warming for a given forcing or scenario. The contributions of each individual climate driver to future changes in PET were examined and revealed that the surface vapor pressure deficit makes a major contribution to changes in PET. Shortwave radiation increases PET in most terrestrial regions, except for northern Africa, East Asia, South Asia, and Australia; the effect of longwave radiation is the opposite to that of shortwave radiation. The contribution of surface wind speed to PET is small, but results in a slight reduction.

摘要

为了评估国际耦合模式比较计划第6阶段(CMIP6)的模拟能力, 本研究选用CMIP5和CMIP6两代气候模式对潜在蒸散发进行对比分析, 并比较了21世纪潜在蒸散发的未来变化及各驱动因素的相对贡献。结果表明: CMIP5与CMIP6模式均可以较好地模拟出潜在蒸散发的增加趋势。基于相同排放情景下, CMIP6多模式结果模拟的未来潜在蒸散发量值将高于CMIP5, 这可能是CMIP6模式体现出了比CMIP5模式更强的升温效应。表层水汽压差仍是导致未来潜在蒸散发变化的主要驱动因子。

KEYWORDS:

• Potential evapotranspiration
• simulation evaluation
• contribution analysis
• CMIP5
• CMIP6

关键词:

• 潜在蒸散发
• 模拟评估
• 贡献分析
• CMIP5
• CMIP6

Supplementary material

Supplemental data for this article can be accessed here.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [grant number 2018YFC1507704] and the National Natural Science Foundation of China [grant numbers 41675094 and 41975115].