基于统计降尺度的东江流域未来气候预估

Climate Projection of Dongjiang River Basin Based on Statistical Downscaling Methods

为提高东江流域未来气候预估结果的可靠性,采用多种方法对CanESM2全球气候模式输出的气温和降水进行了统计降尺度处理。研究发现:SDSM模型和Delta方法分别对东江流域的气温和降水有着较好的降尺度模拟效果。气温上,相较于基准期(1961—2005年),至21世纪末期(2081—2100年),东江流域的日最低气温将升高2.26℃(RCP4.5)和3.65℃(RCP8.5),日平均气温将升高2.70℃(RCP4.5)和4.69℃(RCP8.5),日最高气温将升高2.79℃(RCP4.5)和4.95℃(RCP8.5),其中以夏季和冬季的增幅最为明显;降水上,未来东江流域的年降水量将保持着增加趋势,增速分别为16.4 mm/10a(RCP2.6)、8.7 mm/10a(RCP4.5)和25.4 mm/10a(RCP8.5),且以夏、秋两季增加最为显著。整体来看,未来东江流域在汛期出现极端高温和暴雨洪灾的风险将有所提高。

For higher reliability of climate projections in the Dongjiang River Basin,various methods are used to statistically downscale the air temperature and precipitation output generated by the global climate model CanESM2.The results reveal that SDSM and Delta have good downscaling simulations on the temperature and precipitation in the Dongjiang River Basin,respectively.For temperature,the daily minimum temperature will increase by 2.26℃(RCP4.5)and 3.65℃(RCP8.5);the daily mean temperature will increase by 2.70℃(RCP4.5)and 4.69℃(RCP8.5),and the daily maximum temperature will increase by 2.79℃(RCP4.5)and 4.95℃(RCP8.5)by the end of the 21 st century(2081—2100)relative to the benchmark period(1961—2005).In terms of precipitation,the annual precipitation will rise at a rate of 16.4 mm/10a,8.7 mm/10a,and 25.4 mm/10a under the RCP2.6,RCP4.5,and RCP8.5 scenarios,respectively.In addition,the temperature increase is more prominent in summer and winter,while precipitation increases more in summer and autumn.Overall,the risk of temperature extremes and precipitation extremes in the Dongjiang River Basin during the flood season may increase in the future.