近60 a图们江流域极端气候变化及未来趋势预测

Extreme climate change and future trend prediction in the Tumen River Basin in recent 60 years

【目的】气候变化背景下,洪涝灾害、高温干旱等极端气候事件的发生频率与强度不断增加。图们江位于中国、朝鲜、俄罗斯三国边境,是我国重要的国际河流之一,研究流域内极端气候变化及未来趋势对流域内人民生产生活有重要意义。【方法】以图们江流域为对象,基于流域内和流域附近的11个气象站点1960—2021年的气象数据,采用27个极端气候指数,利用Mann-Kendall趋势检验、Morlet小波分析等方法分析了流域极端气温和降水的时空变化特征,并预测了在SSP1-2.6、SSP2-4.5、SSP5-8.5三种情景下未来极端气候事件的演变特征。【结果】结果显示:(1)近60 a极端气温指数中极端冷指数均呈显著下降趋势,极端暖指数和极值指数均呈显著上升趋势。大部分极端气温指数突变年份集中在1980年以后,且多以35~37 a为第一主周期。极端降水指数中除CWD(持续湿润日数)外,其他指数均呈不显著上升趋势,多以45 a为第一主周期。(2)极端气温指数中极端暖指数和极值指数在汪清北部、和龙南部、安图区域呈现显著下降趋势,珲春南部和延吉-龙井区域则呈显著上升趋势,极端冷指数则相反。与降水强度有关的极端降水指数高值均位于珲春南部区域。(3)从未来不同情景来看,除极端冷指数中的ID0(结冰日数)较于基准期呈下降趋势外,其他气候指数均呈上升趋势,且排放情景越大,增幅越大。【结论】结果表明:图们江流域气温呈变暖趋势,降水呈增多趋势。极端气温指数突变年份集中在1980年以后,极端降水指数无明显突变时期。极端气候指数在流域空间上呈现不同变化特征,珲春南部和延吉-龙井地区发生极端高温事件的概率高于其他地区,珲春南部发生极端降水事件的概率高于其他地区。流域未来极端降水和极端高温事件发生的概率将显著增大,且随着排放情景的增加概率也逐渐增大。

[Objective]Under the background of climate change,the frequency and intensity of extreme climate events such as flood disaster,high temperature and drought are increasing.Tumen River Basin is an important international cross-border river connecting China,South Korea and Russia,and one of the important international rivers in China.It is of great significance to study the extreme climate change and future trend in the basin for the production and life of the people in the basin.[Methods]Based on the meteorological data of 11 meteorological stations in and around the Tumen River Basin from 1960 to 2021,27 extreme climate indices were used to analyze the spatio-temporal changes of extreme temperature and precipitation in the basin by Mann-Kendall trend test and Morlet wavelet analysis.The evolution characteristics of future extreme climate events under three scenarios,SSP1-2.6,SSP2-4.5 and SSP5-8.5,are also predicted.[Results]The result showed that:(1)In the past 60 years,the extreme cold index of the extreme temperature index showed a significant downward trend,while the extreme warm indexand the extreme value index showed a significant upward trend.Most of the abrupt changes in the extreme temperature index were concentrated after 1980,and most of the 35~37 years were the first main cycle.In the extreme precipitation index,except for CWD(number of continuous wet days),the other indexes showed no significant upward trend,and most of them took 45 years as the first main cycle.(2)In the extreme temperature index,the extreme warm index and extreme value index showed a significant downward trend in the north of Wangqing,south of Herong and Antu regions,while the extreme cold index showed a significant upward trend in the south of Hunchun and Yanji-Longjing regions.The high values of extreme precipitation index related to precipitation intensity are all located in the southern region of Hunchun.(3)From different scenarios in the future,except for ID0(number of freezing days)in the extreme cold index,which shows a decreasing trend compared with the base period,other climate indices show an increasing trend,and the greater the emission scenario,the greater the increase.[Conclusion]The results show that the temperature of Tumen River Basin is warming,and the precipitation is increasing.The abrupt change of extreme temperature index was concentrated after 1980,while the abrupt change of extreme precipitation index was not obvious.The extreme climate index showed different spatial characteristics,the probability of extreme high temperature events in south Hunchun and Yanji-Longjing region was higher than other regions,and the probability of extreme precipitation events in south Hunchun was higher than other regions.The probability of extreme precipitation and extreme high temperature events will increase significantly in the future,and the probability will gradually increase with the increase of emission scenarios.