近60年中国干湿气候变化特征及其未来趋势预估

Characteristics of Dry-Wet Climate Change in China during the Past 60 Years and Its Trends Projection

摘要: 本文基于经过均一化订正的共2255个气象站近60年(1961~2020年)逐日观测资料，采用修订的FAO56 Penman-Monteith模型计算潜在蒸散量，用年干燥度指数AI研究我国近60年来干湿气候变化特征，并用模式预估资料，分析到本世纪末我国干湿气候的可能变化趋势。研究结果表明，近60年来，我国气候整体处于变湿状态下，气候变湿较明显的区域主要位于我国西部地区，包括新疆大部、青海西部、甘肃和内蒙西部、西藏西北部等地。近10年来我国气候变湿趋势更加显著，与1960年代相比，干旱区总面积减少约65万平方公里。不同气候分区变化具有明显的区域性和阶段性特征。四个季节气候都呈现变湿的趋势，尤其以夏季变湿最为明显。预估资料分析表明，到本世纪末，我国气候总体呈现变干趋势，变干的区域主要位于我国中东部地区，而我国西部地区继续维持目前变湿的趋势。高排放情景下，我国中东部变干趋势和西部变湿趋势比在中等排放情景下更显著。

Abstract: Based on the homogenized daily data of 2255 meteorological stations during the past 60 years from 1961 to 2020, the potential evapotranspiration was calculated using the revised FAO56 Penman-Monteith model, and then the annual AI (aridity index, the ratio of annual potential evapotranspiration to annual precipitation) was employed to analyze the dry-wet climate change in China. The climate models prediction data was used to analyze the possible trends of dry-wet climate in China by the end of this century. The results showed that in recent decades, the climate in China was in the tendency to get wet, and the areas that have become wetter relative to other areas located in the western regions of China, including Xinjiang, western Qinghai, Gansu, western Inner Mongolia, and northwestern Tibet. In recent 10 years, China’s climate has become more humid. Compared with the 1960s, the total area of arid has decreased about 650,000 square kilometers. The changes of different climate zones have obvious regional and periodical characteristics. There was a tendency to get wet in all four seasons, especially in summer. The results show that by the end of this century, the climate in China would have a general trend of becoming drier. The drier areas are mainly located in the central and eastern parts of China, while the western regions of China continue to maintain the wetting trends. In the case of high emission, the trends of drying in the central and eastern and wetting in the west are more significant than in the case of medium emission.