基于MODIS数据的额尔齐斯河上游河冰物候研究

Study on river ice phenology of upper Irtysh River with MODIS data

额尔齐斯河发源于中国新疆阿尔泰山南坡,是中国唯一流入北冰洋的河流。随着中俄“冰上丝绸之路”提出,额尔齐斯河通航具有重要意义,监测其河冰物候变化显得尤为必要。本研究基于2001—2018年MOD09GQ第2波段数据,分析了额尔齐斯河布尔津至斋桑泊段每年河冰物候信息,包括开始封河时间、结束开河时间、冰/雪最大覆盖时间、冰期持续时间、封河速率和开河速率。研究结果表明:(1)MOD09GQ的反射率随河冰开河而逐渐降低,经与南湾水文站实际观测的冰期持续时间相比较,其所得冰期持续时间与实测冰期持续时间变化一致,均略有延长趋势,这表明MOD09GQ能有效监测河冰物候信息;(2)开始封河时间与结束开河时间均有提前趋势,最早开始封河比最晚开始封河提前45天,最早结束开河比最晚结束开河时间提前31天,开始封河比结束开河提前时间更多,导致整个冰期持续时间有延长趋势;(3)封河速率有变慢趋势,开河速率有逐渐加快趋势,这意味着若未来该河段通航,每年通航期将延长,将带来更大的经济效益。

The Irtysh River originates from the southern slope of the Altai Mountains in Xinjiang,China,and is the only river in China that flows into the Arctic Ocean.With the“Polar Silk Road”proposed by China and Rus⁃sia,the navigation of the Irtysh River is of great significance,and it is particularly necessary to monitor the changes of its river ice phenology.Based on the second band data of MOD09GQ from 2001 to 2018,this paper analyzes the annual river ice phenology information of the Irtysh River from Burqin to Lake Zaysan,including the beginning time of river freezing,the end time of river ice breaking,the maximum coverage time of ice/snow,the duration of river ice period,the freezing rate and the breaking rate.The results show that:(1)the re⁃flectivity of MOD09GQ gradually decreases with the opening of the river ice.Compared with the observed dura⁃tion of the river ice period at Nanwan station,the obtained duration of the river ice period coincides with the ob⁃served duration of the river ice period,and has an extended trend.This shows that MOD09GQ can effectively monitor river ice phenology information.(2)The beginning of river closure and the end of river closure both showed an early trend.The beginning of river closure was 45 days earlier than the end of river closure,and the end of river closure was 31 days earlier than the end of river closure.(3)The closure rate tends to slow down and the opening rate tends to accelerate gradually,which means that if the river reaches are navigable in the fu⁃ture,the annual navigation period will be extended.Bring greater economic benefits.