This study introduces a simple and newly developed fluvial inundation parameterization using high-resolution climate model and investigates its impacts on regional climate. The 2009 Red River spring flood is selected as a case study and this approach is tested with the regional climate model, Global Environment Multiscale (GEM) version 4.8 with 10 km resolution, and Canadian Digital Surface Model (CDSM) elevation (~ 20 m). To investigate the impacts of fluvial inundation on regional climate, the sensitivity experiments using different initial conditions for soil moisture are conducted with 1 km resolution through a three-step one-way nesting approach. Generally, new approach can capture the development–decay of fluvial inundation, similar to MODIS observation. The reasonable statistic values (probability of detection, 0.71; false alarm ratio, 0.26) are found on April 15–22 when occurred the largest MODIS-observed fluvial inundation. In sensitivity experiments, the increase of soil moisture by flooding can induce the decrease of albedo, leading to the increase in absorbed solar radiation energy at surface. Most of the absorbed energy is used by the latent heat flux, inducing the temperature cooling and moisture increase. These changes are larger in daytime than nighttime and are statistically significant in only 2 months (May–June) from the flooding, which contribute to the improvement of temperature simulation. The significant decrease and increase of precipitation in northeastern and southeastern regions away from the flooded region, respectively, are noted post-flooding. These changes are closely associated with the decrease and increase of moist static energy by moisture divergence and convergence, respectively.

本研究使用高分辨率气候模型介绍了一种简单而新近开发的河流淹没参数化方法，并研究了其对区域气候的影响。选择2009年红河春季洪水作为案例研究，并使用区域气候模型，分辨率为10 km的全球环境多尺度（GEM）版本4.8和加拿大数字地面模型（CDSM）高度（〜20 m）对该方法进行了测试。 。为了调查河流淹没对区域气候的影响，通过三步单向嵌套方法，以1 km的分辨率进行了使用不同初始条件的土壤湿度敏感性试验。通常，类似于MODIS观测，新方法可以捕获河流淹没的发展-衰减。合理的统计值（检测概率为0.71；误报率为0。26）是在4月15日至22日发现的，当时发生了MODIS观测到的最大河流泛滥。在敏感性实验中，通过洪水增加土壤水分会导致反照率的降低，从而导致地表吸收的太阳辐射能的增加。大部分吸收的能量被潜热通量利用，导致温度降低和水分增加。这些变化在白天比夜间更大，并且在洪水发生后仅两个月（5月至6月）就具有统计学意义，这有助于改善温度模拟。注水后，东北和东南地区远离洪灾地区的降水量显着减少和增加。