Temporal and Spatial Evolution of Precipitation in Response to the Growth of Taiwan Topography

Taiwan is known as one of the best field areas to study the interactions between tectonics, climate and surface processes. One of the main feedback components is the tendency of topography to increase orographically localized precipitation, but it is unclear how climate may have changed over time as Taiwan topography developed. We present results from two regional general circulation models (RegCM4, REMO) to evaluate dynamical and physical atmospheric changes associated with variations in the height of the Taiwanese Central Range. A series of experiments are conducted with topography systematically varying between 0 and 100% of the modern. To best reproduce the Taiwanese topography, our experiments are performed with a horizontal resolution of 10-20km. Our current simulations focus on the understanding of the temporal and spatial evolution of climate in response to surface uplift. Our first objective is to assess the ability of the regional models to simulate modern climate over Taiwan. An initial comparison between simulated and observed data indicates that the limited-domain models perform very well in capturing the spatial precipitation pattern over Taiwan. Simulated high precipitation occurs along the Central Range with maximum annual precipitation in the northeast. Decreasing precipitation rates towards to west and southwest can be observed in model and observational data. Models with spatial resolutions of 50km or more are not capable to reproduce the observed pattern. Our second objective is to investigate the effect of Pliocene growth of the Central Range on regional climate over Taiwan. Preliminary model results indicate that precipitation over Taiwan strongly correlates with topography. Reducing the topography in our model domain results in a significant decrease in precipitation across the entire island. Our goal is to evaluate the climate sensitivity to a range of mountain topographies and quantify threshold elevations needed to induce the modern precipitation magnitudes and pattern over Taiwan. Thus, we provide specific predictions of elevation, precipitation and other climate parameters that can be directly compared with paleoclimate and paleoaltimetry proxies from Taiwan.