台湾中部砾岩地形的变迁研究

The Study of Morphological Changing of Conglomerate Rock Area,Central Taiwan

利用航空摄影测量方法，讨论台风暴雨对台湾的砾岩地形的冲蚀作用；利用航空数值模型的量化比对地表的冲蚀作用力．研究结果显示，台风暴雨的巨大冲蚀力量，对砾岩地表的冲刷与搬运，具有极大的影响．3个时期（1991、1998、2002年）精度达2m的航空照片判读，都显示火炎山地区的地貌，受到公元2001年的桃芝与纳莉台风的影响，有非常大的改变．在1998和2002年之间，2号子集水区下游也呈现河道堆积的现象，厚度达5—6m．这些变迁也是桃芝台风与纳莉台风所带来的影响．

This study focuses on the influence of rainstorm by typhoon on conglomerate rock area. It is found that the morphology of the conglomerate rock at Hoyenshan area was significantly modified by Typhoon Toraji and Nari occurred in 2001. Photogrammetry method is used for the comparison of erosion. Changes associated with this event were quantified using the 2m posted digital terrain models and orthophoto maps. These enabled, for the 3 periods considered, extraction of channel profiles and cross sections, and area extent and direction of the erosion surfaces. The analysis demonstrates significant incisions of some channels at up to 15m for No. 2 sub-catchment with sediment deposition accounting for between 5 m and 6 m of elevation increase in the valley floors during 1998 and 2002.