New Observations of the Planetary Boundary Layer from GPS Radio Occultation

GPS radio occultation (RO) measurements have emerged as a new data source for remotely sensing the vertical thermodynamic structure of the planetary boundary layer (PBL). With high vertical resolution (100-200 m), the ability to penetrate cloud, and good global and diurnal cycle sampling, GPS RO provides a unique opportunity for the remote sensing of the PBL. In this talk, we will describe algorithms for computing the PBL heights from vertical profiles of refractivity and specific humidity and discuss their strengths and limitations. We will identify the regions where GPS RO methods work best and examine the inversion layer and thickness associated with the top of the PBL. Comparisons of PBL heights, inversion strengths (defined in terms of refractivity and humidity), and variability with radiosonde soundings and models will be presented.