土壤湿度影响中国夏季气候的数值试验

A numerical experiment on the effect of soil moisture to summer climate over China.

  • 摘要: 利用“全球土壤湿度计划第2阶段”提供的土壤湿度资料强迫区域气候模式RegCM3,通过数值试验讨论了土壤湿度对东亚夏季气候模拟效果的影响。结果表明,合理考虑土壤湿度的作用,能够提高区域气候模式对中国夏季降水和2 m气温的空间分布型及逐日变化的模拟效果;模拟结果与观测的相关分析显示,降水和2 m气温的年际变化都得到了有效改进,这种改进在气温上尤为明显。不过上述改进具有区域依赖性。数值试验结果表明,气温对土壤湿度的敏感性强于降水,这也从一个侧面说明提高降水模拟效果的难度。总体而言,合理的土壤湿度能够提高区域气候模式对中国夏季气候的模拟能力。因此,合理描述土壤湿度的变化,是提高中国夏季气候预报技巧的潜在途径之一。

     

    Abstract: To understand the impact of soil moisture on summer climate over China, the regional climate model RegCM3 was forced by “observational” soil moisture data from the Global Soil Wetness Project (GSWP). The forcing of soil moisture produces a more realistic summer climate. Improvement is evident in the spatial patterns of both precipitation and surface (2 m) air temperature, as well as the daily variation of precipitation and surface air temperature in summer. The interannual variations of precipitation and temperature are also improved, as indicated by the increased correlation coefficients. The improvement is however regiondependent. The model response indicates that the sensitivity of surface air temperature to soil moisture is stronger than that of precipitation. The modeled results suggest that the soil moisture may serve as a useful forcing factor in improving the seasonal forecast skill over China. 

     

/

返回文章
返回