成都市地面相对湿度变化特征及模拟研究

Variation Characteristics and Numerical Simulation of Surface Relative Humidity in Chengdu

摘要: 地面空气湿度广泛影响地球生态系统和人类生活，在诸多领域具有重要意义，本文利用成都市2020~2024年期间地面相对湿度观测数据，运用统计和数值模拟相结合的方法研究其演变特征，结果表明：2020~2024年成都市平均地面空气相对湿度为79.32%，近五年呈明显下降趋势，五年降幅为2.6%；相对湿度季节变化和日变化显著，季节变化呈“秋高春低”，日变化呈现“先降后升”趋势，二阶多项式和正弦函数可较好拟合其变化特征；WRF模式模拟试验中，陆面过程选取Noah参数化方案时，模拟的相对湿度与观测值吻合度最高，该方案可应用于成都地区缺少地面观测数据的区域，为气象研究、环境治理和农业生产等方面提供数据基础。

Abstract: Surface air humidity widely influences global ecosystems and human life, holding significant importance in numerous fields. This study utilizes surface relative humidity observation data in Chengdu from 2020 to 2024, employing a combination of statistical and numerical simulation methods to investigate its evolution characteristics. The results show that the average surface air relative humidity in Chengdu from 2020 to 2024 was 79.32%, exhibiting a remarkable downward trend in the past five years with a five-year decline of 2.6%. The relative humidity demonstrates significant seasonal and diurnal variations: the seasonal variation shows a pattern of “high in autumn and low in spring,” while the diurnal variation follows a “first decrease then increase” trend. Second-order polynomials and sine functions can effectively fit these variation characteristics. In WRF model simulation experiments, when the Noah parameterization scheme is selected for land surface processes, the simulated relative humidity shows the highest consistency with observed values. This scheme can be applied to areas lacking ground observation data in Chengdu, providing a data foundation for meteorological research, environmental governance, agricultural production, and other aspects.