This study investigated the effects of activating convective parameterization (CP) in higher-resolution domains of a regional climate model, the Weather and Research Forecast (WRF) model, on watershed-scale precipitation by means of sensitivity analysis. The sensitivity analysis was conducted over three watersheds in the Hokkaido region, Japan. Three nested domains of 27, 9, and 3 km of horizontal resolution were set over the three study watersheds. Then, two types of sensitivity analysis were conducted. First, 36 of the single-year simulations were run with 12 combinations of two cloud microphysics (MP) schemes and six CP schemes and with three types of CP activation; activating a CP scheme only in the outermost domain, in the outermost and middle domain, and in all three domains. After the single-year simulations, long-term (32-year) simulations were conducted using an MP × CP combination with the three types of CP activation. The two-sensitivity analysis shows that activating CP in the higher-resolution domains does not always improve watershed-scale precipitation, but it has a high possibility of improving the results. Moreover, the improvement via activating CP in higher-resolution domains may continue for a long-term period.

本研究通过敏感性分析，研究了在区域气候模型（天气和研究预报（WRF）模型）的高分辨率区域中激活对流参数化（CP）对流域尺度降水的影响。对日本北海道地区的三个流域进行了敏感性分析。在三个研究分水岭上设置了三个嵌套域，它们的水平分辨率分别为27、9和3 km。然后，进行了两种类型的灵敏度分析。首先，用两种云微物理学（MP）方案和六个CP方案的12种组合以及三种类型的CP激活运行了36个单年模拟。仅在最外部的域，最外部和中间的域以及所有三个域中激活CP方案。经过一年的模拟，使用MP×CP与三种类型的CP激活进行长期（32年）模拟。二次灵敏度分析表明，在较高分辨率域中激活CP并不总是能改善流域尺度的降水，但很有可能改善结果。此外，通过在较高分辨率域中激活CP的改进可能会持续很长时间。