Detecting Planetary Boundary Clouds and Relate to Surface Meteorological Parameters over a Complex Landscape

This study shows the results of the presence of Planetary Boundary Layer clouds (PBLc) and the related surface beneath. Even though the Howard University Beltsville Campus (HUBC) has a complex landscape, it can be separated in a more “homogeneous” sectors: commercial/industrial sector, suburban sprawling, and agricultural fields mixed with a mix of deciduous and conifer forest. Since 2006, this site has been monitoring almost continuously micro-meteorological parameters and a ceilometer (Vaisala, CT25K, and later Vaisala CL51) has been collecting cloud base and profile backscatter. When ceilometer's cloud base (h), and the lift condensation level (LCL) estimated from tower data have a good agreement is considered a PBLc. They correlate well to the surface parameters, such as temperature, humidity, wind direction and speed, and turbulent fluxes, according to the upwind fetch. Highest hc values are found when winds come from the industrial sector, and lowest when it winds come from the suburban sector. This sector partition is also followed by turbulent fluxes (friction velocity, sensible heat and latent heat flux), indicating that local effects on the formation a PBLc. However, a spatial analysis is also necessary to determine the importance of larger spatial scale meteorological phenomena to PBLc. Results at HUBV with surrounding National Weather Service – Automated Surface Observatory System (NWS-ASOS) stations that have ceilometer data are also shown.