Estimation of Planetary Boundary Layer Heights from COSMIC, CLIPSO, and High Resolution Radiosondes during the VOCALS-REx

In this study, the planetary boundary layer heights (PBLH) derived from FORMOSAT-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) data are compared to those derived from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements, and high resolution radiosonde measurements during the VOCALS-REx (the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment) period. The VOCALS-REx was conducted over the Southeast Pacific during October and November 2008, where wide spread persistent stratocumulus clouds occurred. The PBLH is usually well defined by the height of these clouds. With high vertical resolution RO data (about 60 meters in the lower troposphere), RO data are very useful to detect the PBLH. Although RO measurements are not sensitive to clouds, they are very sensitive to the vertical gradients of bending angle and refractivity, which depend on temperature, pressure, and water vapor profiles. The PBLH derived by using different RO variables (i.e., bending angles, refractivity, and partial water vapor pressure) are also compared. PBL heights determined by RO measurements are shown to be quite accurate compared to the CALIOP and radiosonde observations.