Linking landscape characteristics to the stream mean transit time and event water ratio on subtropical montane catchments

• Main Authors: Chiao-Ying Lan, 藍巧穎
• Other Authors: 黃誌川
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/985uaz

碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 106 === Mean transit time (MTT) and event water ratio (Qe%) are determinants of biogeochemical cycle. However, MTT and Qe% in subtropical montane catchments are rarely discussed, particularly during typhoon invasions. In this study, the transfer function hydrograph separation model (TRANSEP) embedded with 4 TTDs (GM, EXP, TPLR, DM) was applied to estimate MTTs and Qe% in 5 catchments (5-195 km2) in Ping-Lin, Taiwan during a storm event. Results showed that (1) the EXP model outperformed other three TTDs, which can simulate runoff and δ18O tracer with high NSE of 0.90 and 0.87, indicating a well-mixed behavior during typhoon invasion; (2) the MTTs (2.8-5.5 hours) and the Qe% (19-29%) demonstrated quick conversion from rainfall to streamflow; (3) locally, the mean elevation, perimeter and mean slope can estimate the MTT well (R2=0.99), but not for global scale, probably due to the complexity of water transport dynamic; (4) both locally and globally, Qe% can be well estimated by landscape characteristics supporting the steep landscape is unfavorable with event water generation.