Effects of land surface hydrological processes on soil moisture and coupled impact on the meteorological characteristics

• Main Authors: Tzu-shun Lin, 林梓舜
• Other Authors: Fang-yi Cheng
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/71897464797082564777

碩士 === 國立中央大學 === 大氣物理研究所 === 102 === Heat and water storages of soil conditions memorize the signals of atmospheric information including short-term weather events and long-term climate anomalies. The amount of soil water is critical in determining the performance of numerical weather predictions, and affects the surface energy budgets. The spatial patterns of soil moisture are not only the results of land surface hydrological processes including precipitation, evapotranspiration, groundwater, and surface and subsurface runoff processes, but also are affected by the heterogeneity of topography, soil properties, and land cover characteristics as well. In order to present the effects of land surface hydrological processes on soil moisture and its feedback on the meteorological characteristics, the two-way coupled WRF-Hydro modeling system is applied from 29 August to 11 September 2013. Due to the topography-induced lateral transport of overland flow and saturated subsurface flow, the results from WRF-Hydro model show the increase of soil moisture content in the low-lying areas, while the soil moisture content is reduced over the mountainous regions, and consequently inducing hydrometeorological responses. In addition, the better initial soil states from Global Land Data Assimilation System (GLDAS) and updated soil textures based on field investigations over the Taiwan areas are used to improve the simulations and explore the effects of the GLDAS analysis on the atmospheric model prediction. The soil initialization from GLDAS products can better reproduce the amplitude of temporal variations with observations. Simulated results reveal the spatial distribution of soil moisture is extremely relevant to the soil properties of soil types prescribed in WRF model and surface water budget is analyzed to understand the physical processes. These results show the improvement and heterogeneity of simulated soil moisture though the better representation of initial soil states, soil physical and hydraulic properties, and sub-grid scale hydrological responses. This study sheds light on the importance of fine-scale hydrological processes on soil moisture and its subsequent impact on the coupling of soil moisture-atmosphere interactions in Taiwan.