基于CMIP6集合优化数据集的全球陆地极端气候变化预估

预估极端气候事件趋势能够降低其引起的灾害风险.该文基于CMIP6集合优化数据集EPTGODD-WHU,选取5个极端气候指数,即最高气温极大值(TXx)、最高气温极小值(TXn)、最低气温极大值(TNx)、最低气温极小值(TNn)和最大月降水量(PXx),并结合GIS分析手段,对2021—2100年SSP1-2.6、SSP2-4.5和SSP5-8.5情景下的全球陆地极端气温及降水进行预估.结果表明：1)相较于CMIP单一模式,EPTGODD-WHU数据集模拟性能显著提升,气温及降水的空间相关系数分别达到0.99和0.81.2) SSP5-8.5情景下,年最低气温和最高气温均上升明显,且这种上升趋势年内波动不大,地球陆地极寒地区将面临升温的风险,而赤道等极热地区将处于年内长时间酷热状态.3)六大洲在SSP5-8.5情景下的极端降水整体上升趋势最剧烈,但北美洲密西西比平原和滨海平原的地区在SSP5-8.5情景下在未来面临较高的旱灾风险.4)中国西南部地区的极端降水在三个情景下均呈稳定的增幅,且增幅高达60%,预示面临较高的洪灾风险.

Projection of extreme climate change over global continent based on CMIP6 ensemble dataset

Projecting the trend of extreme climate events can reduce the risk of disasters. Based on the CMIP6 ensemble dataset EPTGODD-WHU, extreme climate indices which included the maximum value of maximum monthly temperature (TXx), the minimum value of maximum monthly temperature (TXn), the maximum value of minimum monthly temperature (TNx), the minimum value of minimum monthly temperature (TNn) and the maximum monthly precipitation (PXx), were selected in combination of GIS analysis methods to estimate the global continent extreme temperature and precipitation in the scenarios of SSP1-2.6, SSP2-4.5 and SSP5-8.5 in 2021-2100 in this study. The results are shown as follows. 1) Compared with the CMIP single model, the simulation performance of the EPTGODD-WHU dataset is significantly improved, and the spatial correlation coefficients of temperature and precipitation are 0.99 and 0.81, respectively. 2) Under the SSP5-8.5 scenario, the annual minimum temperature and maximum temperature increase significantly with little fluctuation within the year is stable. The extremely cold regions of the earth’s land will face a higher risk of warming, while the extremely warm regions such as the equator will bear a long-term hot state. 3) Under the SSP5-8.5 scenario, the extreme precipitation in the six continents will face a severe upward change trend, however, Mississippi Plain and the Coastal Plain in North America face higher drought risk in the future under the SSP5-8.5 scenario. 4) The extreme precipitation in southwestern China shows a steady increase under the three scenarios, and the increase rate reaches to 60%, which indicates a higher risk of flooding.