资源环境科技发展态势分析平台

The planetary boundary layer (PBL) height over the U.S. Great and Central Plains during 1992-2012 is examined here using a combination of wind profiler-derived PBL height estimates and reanalysis fields from the Modern Era Retrospective Reanalysis Version 2. The combined analysis allows for a process level study of the reasons behind the monthly mean behavior of the observed PBL heights under clear-sky conditions as well as the PBL height variability. Wind profiler PBL height monthly mean annual cycles were grouped into general categories of behavior, each analyzed using Modern Era Retrospective Reanalysis Version 2 fields of sensible and latent heat flux, surface temperature, net radiation, and soil moisture. In the canonical category the latent heat plays little role in the determination of the monthly mean PBL height, and it follows the annual cycle of the surface temperature. In the other categories, precipitation and latent heat flux had more influence in setting the annual cycle of the PBL height. An analysis of variance revealed that the role of latent heat in determining the PBL height variations is large (explaining up to 40% of PBL height variability) even in the canonical category for which latent heat played no role in setting the monthly mean. In other categories the latent heat explained up to 80% of the PBL height variations. The amount of that influence is shown to be related to the variability of column soil moisture.