流域LUCC水文效应研究中的若干问题探讨

Discussion on Some Issues of Hydrological Effects of Watershed Land Use and Land Cover Change

随着全球变化研究的深入.土地利用/覆被变化(LUCC)的水文效应研究日益成为热点问题。综合国内外研究进展.论文就流域土地利用/覆被变化水文效应研究中的几个问题进行了总结和探讨:子流域和水文响应单元是分布式水文模型对流域基本空间单元的理想划分:对国内外现有的土地利用分类系统进行了适当的凋整和归并.建立了基于水文响应研究的土地利用分类系统,将土地利用分为9个Ⅰ级类和21个Ⅱ级类:土地利用/覆被变化情景分析的常用方法有参照对比法、历史反演法、模型预测法、极端土地利用法、土地利用空间配置法等。

With the research on global change deepening, hydrological effects of Land-use and Land-cover change (LUCC) are becoming the focus of attention. Based on the progress in the study on hydrological effects of watershed land use and land cover change, some issues are summarized and discussed. Spatially distributed or semi-distributed hydrological models have important applications in the interpretation and prediction of the effects of land use change. Considering the spatial variation of precipitation and land surface characteristics, the precondition of distributed hydrological model is to partition a watershed into many non-nesting units. There are four methods to delineate watershed units: partitioning watershed by precipitation gages, partitioning watershed into rectangle grids, partitioning a watershed into 'homogeneous' units known as hydrologic response units, HRU, by physical characteristics, and partitioning watershed into sub-watershed by divides. Sub-watersheds and hydrological response units, HRU, are preferred units in distributed hydrological model. The land use and land cover classification system based on hydrological response is established by means of adjusting and merging existing classification. There are 9 level- Ⅰ categories and 21 level-Ⅱ categories in the land use and land cover classification system. Level- I categories include arable land, grass land, forest land, orchard, shrub, water, built-up land, barren land and wetland .The methods of setting up land use and land cover change scenarios include paired contrast, historical speculation, modeling forecast, extreme land use and land use spatial allocation, etc.