基于Budyko假设的瀑河上游年均径流深变化归因分析

Attribution analysis of annual average runoff depth variation in the upper reaches of the Bao River based on the Budyko hypothesis

近年来京津冀水资源短缺对生态环境有着重要的影响,为量化区分气候变化和人类活动对水资源的影响,针对京津冀水源涵养区北部山区典型小流域瀑河上游开展径流深变化归因分析。利用瀑河上游1981—2020年降水、蒸发和径流等资料,采用曼-肯德尔法(Mann-Kendall method,M-K法)检验确定1981—2006年为基准期、2007—2020年为变化期。分析发现,与基准期相比,变化期年均径流深减少了46.47 mm,约占基准期径流深总量的77.10%。利用重标度极差分析法(Rescaled Range Analysis,R/S法),推断瀑河上游未来年均径流深与1981—2020年间年均径流深的变化趋势相反,即呈现相对平稳的增加趋势。基于Budyko假设原理,定量地评价了气候变化(降水量和潜在蒸散发)和人类活动对该区年径流深的影响程度,气候变化对径流影响贡献率为40.30%,人类活动影响的贡献率为59.71%。人类活动对径流的影响主要通过土地利用类型的改变,研究区共有30.28%的土地发生了相互转化,其中乔木林地2020年较1985年增加了67.61%,极大程度增加了研究区的水源涵养能力,同时植被覆盖度的增加也一定程度上降低了潜在蒸散发。研究可增进对京津冀北部山丘区水文水资源的认识,为京津冀水源涵养功能驱动因素筛选提供一定的参考。

In recent years,the shortage of water resources in Beijing-Tianjin-Hebei region has an important impact on the ecological environment.In order to quantify the impact of human activities and climate change on water resources,the authors in this article conducted an attribution analysis of runoff changes in typical small watersheds in the northern mountainous areas of Beijing-Tianjin-Hebei water conservation area.Based on the data of precipitation,evaporation,and runoff in the upper reaches of the Bao River from 1981 to 2020 and the Mann Kendall method(M-K method),the baseline period was determined from 1981 to 2006 and the variation period was determined from 2007 to 2020.The results show that the annual average runoff depth during the variation period decreased 46.47 mm compared with the baseline period,accounting for 77.10%of runoff the total depth during the baseline period.Based on Rescaled Range Analysis(R/S),the future annual average runoff depth of the upper reaches in the Bao River was deduced to keep an opposite changing trend compared with the annual average runoff depth from 1981 to 2020,showing a stable increasing trend.Based on the Budyko hypothesis principle,the impact of climate change and human activities on the annual runoff depth in this region was quantitatively evaluated.The contribution rate of climate change to the runoff depth was 40.29%,and the contribution rate of human activities to the runoff depth was 59.71%.The impact of human activities on the runoff depth is mainly through changes in the land use type.A total of 30.28%of the land in the study area has undergone mutual transformation,with an increase of 67.61%in tree forests in 2020 compared to 1985,which greatly enhanced the water conservation capacity of the study area.The increase on vegetation coverage also reduces the potential evaporation.The research results could enhance the understanding of hydrological and water resources in the hilly areas of the northern Beijing-Tianjin-Hebei region,and provide some references for screening the driving factors of water source conservation function in Beijing-Tianjin-Hebei region.