The study area, Tseng-Wen Reservoir basin, receives temporally uneven precipitation and is thus a basin prone to suffer droughts. This study investigated the hydrologic droughts and low flow properties in the Tseng-Wen Reservoir basin under climate change scenarios. Projected climate change data were originally the large-scale climate fields output from six general circulation models in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Those large-scale climate change data were then transformed into local-scale precipitation data over the study basin by a two-stage statistical downscaling method, consisting of a spatial downscaling method using the singular value decomposition method and a temporal downscaling method using a weather generator. The modified HBV (Hydrologiska Byråns Vattenbalansavdelning) model was used to simulate the projected streamflow under climate change scenarios. Hydrological droughts were then identified pertaining to streamflow series by the threshold method, and drought and low flow properties were analyzed. The following summarizes important findings in this study: (1) Projected precipitation increases in the wet season, and either increases or decreases in the dry season pertaining to different months. (2) Projected streamflow increases during March to September, but decreases otherwise. (3) Projected low flow tends to decrease. (4) Scenario droughts may become more frequent, but their duration and magnitude may become more diverse than the baseline droughts. (5) The times of start and end of scenario droughts may occur earlier than baseline droughts. (6) Different trends of changes in hydrologic droughts were found under different general circulation models, thus uncertainties from general circulation models and other sources, e.g. downscaling process, should be taken into account.
|Number of pages||17|
|Journal||Journal of Taiwan Agricultural Engineering|
|Publication status||Published - 2011 Sep 1|
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)