气候变化与冻土退化对海拉尔河流域径流组分的影响研究

Impact of climate change and permafrost degradation on runoff components in Hailar River Basin

摘要

【目的】探究气候变化与冻土退化对海拉尔流域径流组分的影响，对揭示寒区水文演变机制以及优化寒区流域水资源适应性管理策略具有重要意义。【方法】基于1980—2012年水文、气象及冻土观测数据，采用数字滤波法划分径流组分，利用Stefan模型模拟冻土变化特征，结合灰色关联度法分析降水、气温、冻土深和植被覆盖对径流组分变化的相对贡献。【结果】结果显示：(1)研究期内流域径流显著减少，各站径流减少速率为15.5~43.6 mm·(10 a)^-1,基流占总径流比例超过70%。(2)Stefan模型在流域年最大冻结深度模拟效果较好，流域最大冻结深度呈显著减小趋势，速率为8.8~11.2 cm·(10 a)^-1。(3)灰色关联度结果显示，冷季径流与冻土关联度最高，为0.78~0.83,而暖季径流与植被覆盖情况关联度最高，为0.79~0.84。气温在所有站点均表现出相对较低的关联度，为0.60~0.69。【结论】结果表明：(1)研究期内流域径流及其组分呈显著下降趋势，而基流在总径流变化中占主导作用。(2)Stefan模型在流域年最大冻结深度中适用性较好，流域整体冻土退化剧烈且空间分异显著。(3)冷季径流主要受冻土退化影响，暖季径流则受植被覆盖主导，季节性差异显著，而气温通过影响冻土消融和植被生长间接作用于径流。

Abstract

[Objective] Investigating the impact of climate change and permafrost degradation on runoff components in the Hailar River Basin is important for revealing hydrological evolution mechanisms and optimizing adaptive water resource management strategies in river basins of cold regions. [Methods] Using hydrological, meteorological, and permafrost observation data from 1980 to 2012, runoff components were partitioned using the digital filtering method. Permafrost variation characteristics were simulated using the Stefan model, and the relative contributions of precipitation, air temperature, permafrost depth, and vegetation cover to variations in runoff components were analyzed using the grey relational analysis method. [Results] The result showed that:(1) runoff in the river basin decreased significantly during the study period. The reduction rate at each station ranged from 15.5 mm·(10a)^-1 to 43.6 mm·(10 a)^-1, and baseflow accounted for over 70% of total runoff.(2) The Stefan model performed well in simulating the annual maximum frozen depth in the river basin. The maximum frozen depth showed a significant decreasing trend at a rate of 8.8~11.2 cm·(10 a)^-1.(3) The grey relational analysis result revealed that cold-season runoff had the highest correlation degree with permafrost, ranging from 0.78 to 0.83, while warm-season runoff had the highest correlation degree with vegetation coverage, ranging from 0.79 to 0.84. Air temperature showed a relatively low correlation degree at all stations, ranging from 0.60 to 0.69. [Conclusion] The result indicate that:(1) runoff and its components in the river basin exhibit a significant declining trend during the study period, with baseflow playing a dominant role in the changes in total runoff.(2) The Stefan model is applicable in simulating the annual maximum frozen depth in the river basin. Overall, permafrost degradation across the river basin is severe and exhibits significant spatial heterogeneity.(3) Cold-season runoff is primarily affected by permafrost degradation, while warm-season runoff is mainly controlled by vegetation cover, showing pronounced seasonal differences. Air temperature affects runoff indirectly by influencing permafrost thaw and vegetation growth.

关键词

气候变化 / 冻土退化 / 径流 / 基流 / 海拉尔河流域 / 降水 / 数字滤波法 / 寒区水文演变机制

Key words

climate change / permafrost degradation / runoff / baseflow / Hailar River Basin / precipitation / digital filtering method / hydrological evolution mechanisms in cold regions

基金资助

国家重点研发计划(2021YFC3200203)