【摘要】 利用黄土高原区域甘肃平凉地区陆面过程与灾害天气观测研究站2016—2017年夏季（6—8月）晴好天气下的观测资料,定量分析了平凉地区土壤湿度在干、中、湿三种不同状况下对地表辐射和地表能量分配及大气边界层的影响,并根据总体变化趋势,将土壤湿度进一步分为干、中区间(0. 158～0. 220 m³·m^-3)和中、湿区间(0. 179～0. 325 m³·m^-3),与波文比、感热通量、潜热通量进行相关性分析,从而探究土壤湿度通过影响地表能量分配和大气边界层进而影响降水的可能物理机制。结果表明:（1）土壤湿度变化对反照率影响相对较小,对波文比影响显著,主要是影响感热、潜热变化,即影响地表能量分配过程。随着土壤湿度增加,潜热增大,感热减小,波文比显著降低;土壤湿度变化对地表净辐射影响显著,主要影响净长波辐射变化,随着土壤湿度增加,净短波辐射呈现略微增加,净长波辐射显著增加。（2）土壤湿度分区间分析结果显示,土壤湿度在干、中区间(0. 158～0. 220 m³·m^-3)对潜热通量以及边界层高度的影响相比土壤湿度在中、湿区间(0. 179～0. 325 m³·m^-3)的影响更大,即土壤偏干情况下,地表通量变化和大气边界层发展更显著。此次观测数据定量分析结果与理论机理较为一致,表明该观测数据的可靠性,可为数值模式在黄土高原区域的模拟提供重要的数据基础。更多还原

【Abstract】 Based on the observational data of land surface processes and disastrous weather observation and research station in Pingliang area of Gansu Province during the summer（ June,July and August） of 2016—2017,the effects of soil moisture on surface radiation,surface energy distribution and the development of atmospheric boundary layer in Pingliang area under dry,medium and wet conditions were quantitatively analyzed. And then,according to the general soil moisture change trend,the soil moisture was further divided into dry-medium sections(0. 158～0. 22 m³·m^-3) and medium-wet( 0. 179～0. 325 m³·m^-3) sections and the correlation between soil moisture and Bowen’s ratio,sensible heat flux and latent heat flux was analyzed to explore the possible physical mechanism of soil moisture affecting precipitation by affecting surface turbulent energy distribution and the development of atmospheric boundary layer. The results show that:（ 1） Soil moisture has a relatively small impact on albedo,and has a significant impact on Bowen’s ratio,mainly affecting sensible and latent heat changes,that is,affecting the process of surface energy distribution. With the increase of soil moisture,latent heat increases,sensible heat decreases and Bowen ratio decreases significantly. The change of soil moisture has a significant impact on net radiation,mainly on net long-wave radiation. With the increase of soil moisture,net short-wave radiation increases slightly and net long-wave radiation increases significantly.（ 2） Inter-zonal analysis of soil moisture showed that the influence of soil moisture on latent heat flux and boundary layer height was greater in the dry and middle sections( 0. 158～0. 220 m³·m^-3) than in the middle and wet sections( 0. 179～0. 325 m³·m^-3).That is to say,the change of surface flux and the development of atmospheric boundary layer are more significant when the soil is dry. The results of quantitative analysis of the observations are consistent with the theoretical mechanism,which shows the reliability of the observed data and the data can provide an important data basis for the simulation of the numerical model in the Loess Plateau region.更多还原