This study estimated global potential evapotranspiration (PET) using six climate variables of 14 CMIP6 GCMs at different latitudes of both hemispheres. Hargreaves-Samani (HS) and Penman-Monteith (PM) were used to estimate historical and future PETs. To evaluate the historical reproducibility of the six climate variables of the CMIP6 GCMs, five evaluation indicators were used and compared with the NCEP/NCAR reanalysis data. Based on the evaluation metrics, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was used to calculate the weights for Multi-Model Ensemble (MME) for each band of latitude. After that, the projected annual and seasonal PETs were estimated for the near (2031–2065) and far (2066–2100) futures. The change rate of PET for five timeframes (Annual, Spring, Summer, Fall, and Winter) was calculated for four socioeconomic shared pathways (SSPs). As a result, the PM's PET and HS's PET for all scenarios showed the highest increased signals at 75.5° ∼ 90° in the northern hemisphere (NH) compared to the other latitudes. Especially, the change in the HS of SSP5–8.5 was increased by 26.4% in NH latitude 45.5° to 60° (NL4) compared to the base period. Furthermore, the changes in PET of PM and HS for December, January, and February (DJF) and September, October, and November (SON), and June, July, and August (JJA) lead to remarkably high increases in both hemispheres, irrespective of the level of the emission scenario, completely ignoring the seasonal water cycle in the historical period (1950–2014).

中文翻译：

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基于 CMIP6 的按纬度使用 Penman-Monteith 和 Hargreaves-Samani 方法计算的全球未来潜在蒸散发信号

本研究使用两个半球不同纬度的 14 个 CMIP6 GCM 的 6 个气候变量估计了全球潜在蒸散量 (PET)。 Hargreaves-Samani (HS) 和 Penman-Monteith (PM) 用于估计历史和未来的 PET。为了评估CMIP6 GCM的六个气候变量的历史再现性，使用了五个评估指标，并与NCEP/NCAR再分析数据进行了比较。根据评估指标，使用理想解相似度偏好排序技术 (TOPSIS) 计算每个纬度带的多模型集成 (MME) 权重。之后，对近期（2031-2065）和远（2066-2100）未来的年度和季节性 PET 进行了估算。针对四种社会经济共享路径 (SSP) 计算了五个时间范围（年度、春季、夏季、秋季和冬季）的 PET 变化率。结果，与其他纬度相比，PM 的 PET 和 HS 的 PET 在所有场景中都显示出北半球 (NH) 75.5° ∼ 90° 处信号增强最多。特别是，在北纬45.5°至60°（NL4），SSP5-8.5的HS变化与基期相比增加了26.4%。此外，12月、1月和2月（DJF）以及9月、10月和11月（SON）以及6月、7月和8月（JJA）PM和HS的PET变化导致两个半球显着大幅增加，无论排放情景水平如何，完全忽略历史时期（1950-2014）的季节性水循环。