地理科学进展 ›› 2015, Vol. 34 ›› Issue (8): 1039-1051.doi: 10.18306/dlkxjz.2015.08.011

• 水文与气候 • 上一篇    下一篇

降水和植被变化对径流影响的尺度效应——以陕北黄土丘陵沟壑区为例

丁婧祎1(), 赵文武1*(), 王军2, 房学宁1   

  1. 1. 北京师范大学资源学院,地表过程与资源生态国家重点实验室,北京 100875
    2. 国土资源部土地整治重点实验室, 北京 100035
  • 出版日期:2015-08-25 发布日期:2015-08-25
  • 作者简介:

    作者简介:丁婧祎(1993-),女,河南许昌人,硕士研究生,主要从事土地利用与生态水文过程等方面研究,E-mail: jyd2104011510@163.com

  • 基金资助:
    国土资源部土地整治中心开放课题项目(2015-01-62);国家自然科学基金项目(41171069)

Scale effect of the impact on runoff of variations in precipitation/vegetation: taking northern Shaanxi loess hilly-gully region as an example

DING Jingyi1(), ZHAO Wenwu1,*(), WANG Jun2, FANG Xuening1   

  1. 1. College of Resources and Technology, State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
    2. Key Laboratory of Land Consolidation and Rehabilitation, Ministry of Land and Resources, Beijing 100035, China
  • Online:2015-08-25 Published:2015-08-25
  • Contact: ZHAO Wenwu E-mail:jyd2104011510@163.com;zhaoww@bnu.edu.cn

摘要:

自黄土高原退耕还林还草政策实施以来,在水源涵养功能明显提升的同时径流显著减少,导致该区域出现了水源涵养服务与水供给服务间的权衡问题。为探究径流减少的原因,进而为不同空间尺度的生态系统服务权衡提供支撑,本文分析了陕北黄土丘陵沟壑区2006-2011年降水和植被变化对径流影响的尺度效应。结果表明:研究区域内汛期降水量呈现出由东南向西北逐渐减少的空间分异特征;在研究时段内,植被恢复效果明显,近8成地区植被覆盖状况得到了改善,尤其是植被覆盖较差的地区恢复效果更为显著;在各子流域中,降水与径流间呈现出显著的正相关性,二者的相关系数随着子流域面积的增加而增大,表现出明显的尺度效应。随着子流域面积增大,15°以上土地比例增加,陡坡植被覆盖类型趋于均一化,具有显著截流功能的林地呈现减少趋势是尺度效应形成的主要原因。NDVI与径流的相关性不显著,二者的相关系数随着子流域面积变化的规律性不强,植被对径流影响没有明显的尺度效应。

关键词: NDVI, 降水, 径流, 尺度效应, 权衡, 黄土丘陵沟壑区

Abstract:

Water conservation capability of the loess plateau increased significantly since the Grain for Green project started. At the same time, the amount of runoff significantly reduced, resulting in the question of how to balance the water conservation needs and the need for water supply in the region. In order to explore causes of the runoff reduction and provide support for balancing different needs for water at different scales, the variation of precipitation and vegetation as well as the scale effect of its impact on runoff in northern Shaanxi loess hilly-gully region during 2006 to 2011 were examined. The results show that: Precipitation of flood season gradually reduced from southeast to northwest in the study area. During the research period, vegetation restored significantly, nearly 80% of vegetated area was improved, especially in areas with poor vegetation conditions. Precipitation and runoff had significant positive correlation. With the increase of sub-watershed area,the correlation of precipitation and runoff increased, which shows a clear scale effect. The main reason was that land use structure above 15° of slope changed along with the spatial scale—vegetation types at steep slope tended to be homogenous and forest that has significant water conservation function decreased along with the increase in sub-watershed area. The correlation between NDVI and runoff was neither significant nor forming a clear relationship with the area of sub-watersheds, therefore the scale effect of vegetation influence on runoff was not obvious.

Key words: NDVI, precipitation, runoff, scale effect, tradeoff, loess hilly-gully region