题 目： Quantifying the relations between forest changes and water at a large spatial scale
报告人： 魏晓华 教授
加拿大不列颠哥伦比亚大学(UBC) 地球与环境科学系流域生态研究首席科学家
时 间： 2010年10月23日下午3:30
地 点： 蒙民伟楼913会议室
简 介：
魏晓华，博士。加拿大不列颠哥伦比亚大学(UBC) 地球与环境科学系流域生态研究首席科学家, 教授。从事流域生态水文、森林生态、气候变化方面的研究。 国际著名刊物 (Forest Ecology and Management) 编委, 美国水资源协会刊物(JAWRA)（2008专刊）的特邀副主编与Eco-hydrology (2010专刊)的特邀主编, 主持加拿大国家战略重大科学基金等6个在研项目, 共发表文章50篇。 个人网页：http://people.ok.ubc.ca/adamwei/
Abstract
Climatic variability and forest disturbance are commonly recognized as two major drivers influencing streamflow change in large-scale forested watersheds. The greatest challenge in evaluating quantitative hydrological effects of forest disturbance is the removal of climatic effect on hydrology. In this presentation, we will describe an innovative methodology designed to quantify respective contributions of large-scale forest disturbance and climatic variability on streamflow using the Willow watershed (2860 km2) situated in the central part of British Columbia, Canada. Long-term (>50 years) data on hydrology, climate and timber harvesting history represented by equivalent clear-cutting area (ECA) were available for this study. Firstly, effective precipitation, an integrated climatic index, was generated by subtracting actual evapotranspiration from precipitation. Secondly, the modified double mass curves (DMCs) were developed by plotting accumulated annual streamflow against annual effective precipitation, which presented a much clearer picture of the cumulative effects of forest disturbance on streamflow following removal of climatic influence. The average annual streamflow changes that attributed to forest disturbances and climatic variability were then estimated to be +71.4 and -85.8 mm, respectively. The positive (increasing) and negative (decreasing) values in streamflow change indicated opposite change directions, which suggest offsetting effect between forest disturbance and climatic variability in the study watershed. Finally, a factored ARIMA model was generated to establish quantitative relationships between accumulated annual streamflow deviation and annual ECA. The model was then used to project streamflow change under various timber harvesting scenarios. The methodology can be effectively applied to any large-scale single watershed where long-term data are available.
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国际地球系统科学研究所
2010.10.20
