黄河未来气候情景下冰情特征演变分析

Analysis of the evolution of ice characteristics in the Yellow River under future climate scenarios

了解未来气候变化如何影响河流冰情特征对于研究冰凌洪水灾害、水电生产以及大坝管理运行等问题至关重要。基于黄河流域气象观测数据以及第六次国际耦合模式比较计划(CMIP6)中8种全球气候模式(GCMs)的日均气温数据,评估了各GCMs在分位数增量映射(QDM)偏差校正前后对于黄河流域凌汛期日平均气温的模拟能力,预估了黄河流域未来凌汛期气温变化趋势。建立了最大冰厚以及封冻历时预测模型,并预估了黄河防凌重点区域黄河宁蒙段未来最大冰厚以及封冻历时的变化趋势。研究表明,在SSP1-2.6、SSP2-4.5和SSP5-8.5三种气候情景下预计2015—2100年期间黄河流域凌汛期平均气温升温速率分别为0.014、0.031和0.067℃a,黄河巴彦高勒断面21世纪内最大冰厚值将会分别下降8.5、19.5和39.5 cm。SSP2-4.5情景下,随着未来气温升高,2070年之后河道断面仅存一定宽度岸冰、河道中央存在较大清沟的现象将会频繁出现。未来黄河宁蒙段巴彦高勒、三湖河口以及头道拐断面的封冻历时将会呈现出不同程度的缩短趋势,其中巴彦高勒断面缩短趋势最为明显,三种气候情景下封冻历时分别以0.13、0.28和0.66 d a的速率缩短,三湖河口及头道拐断面封冻历时缩短速率较为接近,分别为0.07、0.15、0.36以及0.08、0.17、0.39 d a。

Understanding how future climate change will affect river ice characteristics is critical for studying ice flood hazards,hydropower production,and dam management.Based on the meteorological observations in the Yellow River basin and the daily average temperature data from eight GCMs of the CMIP6,the simulation capability of each GCM for the daily mean temperature of the Yellow River Basin during the flooding period before and after the correction of the quantile delta mapping bias was evaluated,and the future temperature trend of the YRB during the ice flooding period was predicted.The prediction models of maximum ice thickness and freeze-up duration were established respectively.The future trends of maximum ice thickness and freeze-up duration in the Ningxia-Mongolia reaches of the Yellow River were predicted.The study shows that the average temperature warming rates during the period 2015—2100 in the Yellow River Basin in the three climate scenarios of SSP1-2.6,SSP2-4.5,and SSP5-8.5 are 0.014,0.031,and 0.067℃per decade,respectively.The maximum ice thickness values at Bayangaole are expected to decrease by 8.5,19.5,and 39.5 cm during this century,respectively.The SSP2-4.5 scenario shows that after 2070 only a certain width of bank ice remains in the river cross-section and a large clear channel exists in the middle of the river will occur frequently.In the future,the freezing duration of the Yellow River、Sanhuhekou and Toudaoguai sections of the Yellow River will show different degrees of shortening trend,among which the shortening trend of Bayangaole is the most obvious,the freezing duration of the three climate scenarios is shortened by 0.13,0.28 and 0.66 days per decade,respectively,and the freezing duration of the Sanhuhekou and the Toudaoguai section is relatively close,which is 0.07,0.15,0.36 days perdecade and 0.08,0.17,0.39 days per decade,respectively.