秦岭丹江上游流域水源涵养功能时空变化特征及其影响因素

Temporal and spatial variation characteristics of water conservation function of Upper Danjiang River Basin in Qinling Mountains and its influencing factors

  • 摘要: 良好的水源涵养功能可以调节区域水文循环和保障区域生态安全,与人类生产生活密切相关,如何精准评估水源涵养功能已成为当下生态水文学的研究热点。基于分布式水文土壤植被模型(DHSVM)和水量平衡法,分析秦岭丹江上游流域2010—2020年水源涵养量的时空变化规律,并探明气候变化和土地利用变化对流域水源涵养功能的影响。结果表明:(1)丹江上游流域年水源涵养量平均值为61.60 mm,月水源涵养量平均值为4.3 mm,有年际和年内变化大的特征。(2)水文要素中,降水量、蒸散发量和径流量11年都呈增长趋势,水源涵养量为减少趋势。流域内水源涵养量的空间分布规律为由东南部向西北方向递减。(3)不同时间尺度下影响水源涵养量的主要气象因子不同。在年际尺度下,影响水源涵养量的主要气象驱动因子为降水,表现为促进作用;年内尺度下影响水源涵养量的主要气象因子为降水和气温,分别表现为促进作用和抑制作用。(4)丹江上游流域主要土地利用类型水源涵养量由高到低依次为:草地、林地、耕地。在土地利用类型变化后,草地面积增加,林地和耕地面积减少,流域水源涵养功能提高。本研究可为当地水资源管理和制定生态保护决策提供科学依据。

     

    Abstract: Effective water conservation function can regulate the regional hydrological cycles and ensure the regional ecological security, which are closely related to human production and life. For this reason, the way to accurately evaluate the water conservation function has become a research hot topics in current ecohydrology. Herein, the temporal and spatial variation rules of water conservation in Upper Danjiang River Basin in Qinling Mountains from 2010 to 2020 were analyzed based on the Distributed Hydrology Soil Vegetation Model (DHSVM) and the water balance method, and the effects of changes in climate and land use on the water conservation function of the basin were explored. The results indicate that: (1) The average annual and monthly water conservation of Upper Danjiang River Basin is 61.60 mm and 4.3 mm respectively, showing the characteristics of significant inter-annual and intra-annual variations. (2) In terms of the hydrologic factors, the precipitation, evapotranspiration and runoff all show an increasing trend for 11 year, while the water conservation is in a decreasing trend. Besides, the spatial distribution of water conservation in the basin decreases from southeast to northwest. (3) The primary meteorological factors influencing water conservation vary at different time scales. At the inter-annual scale, precipitation is the main meteorological driving factor affecting water conservation, which is favorable for water conservation. At the intra-annual scale, precipitation and ambient temperature are the main influencing factors of water conservation. Specifically, precipitation is beneficial while ambient temperature is adverse to the water conservation. (4) The main land use types in Upper Danjiang River Basin with the water conservation ranking from high to low are as follows: grassland > woodland > farmland. After the land use types change, the area of grassland increases, while that of woodland and farmland decreases, resulting in the improved water conservation functions within the basin. Generally, this study could provide scientific basis for local water resources management and decision-making on ecological protection.

     

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