基于最新CRU TS V4.05格点资料,系统分析了1951—2020年阿富汗气候要素时空变化特征。结果表明：（1） 阿富汗自西南向东北部分别为极端干旱、干旱、干旱-半湿润和湿润气候区,年平均气温及潜在蒸散量自西南部锡斯坦盆地向东北部瓦罕走廊地区递减,年降水量呈递增的空间分布。（2） 近70 a,阿富汗年及四季平均气温表现为全区一致性地增加且西部增温率大于东部,其中春季的增温幅度最大;阿富汗降水量区域间及季节差异性大,年降水量呈微弱减少趋势[-0.43 mm·(10a)^-1],空间表现为自西南向东北呈“减少-增加-减少”变化;降水集中的冬、春季,降水量为减少趋势。（3） 阿富汗潜在蒸散量大,1951—2020年呈显著的增加[5.59 mm·(10a)^-1],而空间变化与降水相反,中部兴都库什山年潜在蒸散量呈减少趋势;春、夏和秋季潜在蒸散量增加,冬季减少。（4） 近70 a以来,干湿指数（AI）表征阿富汗干湿气候变化趋势不明显,以年际变化为主;空间变化表现为阿富汗西南部极端干旱的锡斯坦盆地干旱加剧,中部兴都库什山经历了“暖湿”化,而降水量最集中的瓦罕走廊地区呈“暖干”化;春季平均AI减小幅度最大,加剧了阶段性干旱风险。21世纪以来,阿富汗经历了气候暖湿化的时期,气温略增加,降水量急剧增多,而潜在蒸散量明显减小,尤以春季变化最为显著,这将对该地区农业生产、冰冻圈风险及水资源管理带来挑战。

The fragile ecosystems of Afghanistan, in the southern arid region of Central Asia, are greatly affected by climate change. In this study, we systematically analyzed the change in the average climate of Afghanistan from 1951 to 2020, in terms of both temporal and spatial patterns, using updated CRU TS V4.05 high-resolution gridded data. Results indicate that the extremely arid, arid, semihumid, and humid climate zones of Afghanistan are distributed from the southwest to the northeast. The annual average air temperature and potential evapotranspiration decreased from the Sistan Basin in the southwest to the Wakhan Corridor in the northeast. By contrast, the annual average precipitation increased. The annual and seasonal average temperature increased consistently, with the most substantial warming over the past 70 years occurring in the western part of Afghanistan; the greatest increase in the seasonal average temperature was in the spring. The data indicated strong spatial heterogeneity in precipitation as well as large seasonal differences. There was a slight decrease in the annual precipitation [-0.43 mm·(10a)^-1] over the study period and a “decrease-increase-decrease” trend in the spatial distribution changes, from the southwest to the northeast. The precipitation was concentrated in winter and spring. From 1951 to 2020, the trend in the potential evapotranspiration in Afghanistan was a significantly upward trend, with a rate of 5.59 mm·(10a)^-1. Annual potential evapotranspiration was found to have decreased over the central region of Afghanistan. Although there were seasonal differences, potential evapotranspiration tended to increase in the spring, summer, and autumn and decrease in the winter. Analysis of the aridity index (AI) revealed interannual variations in the climate of Afghanistan. Drought had intensified in the extremely arid Sistan Basin in the southwest, whereas warmer and wetter weather occurred in the central Hindu Kush region, and the Wahan Corridor area was generally warmer and dryer. The average AI decreased substantially in the spring, leading to the risk of staged drought. Generally, since the beginning of the 21st century, Afghanistan has experienced a slight increase in temperature, a sharp increase in precipitation, and a significant decrease in annual potential evapotranspiration. The region experienced warming and wetting stages, most notably in the spring. In conclusion, all of these changes pose risks and challenges to agricultural production, the cryosphere, and water management.