PBL height can be derived from satellite GPS RO data. Some papers I have come across on the subject are listed below. However I have no specific information about where this data can be obtained.
von Engeln, A., J. Teixeira, J. Wickert, and S. A. Buehler (2005), Using
CHAMP radio occultation data to determine the top altitude of the planetary boundary layer, Geophys. Res. Lett., 32, L06815, doi:10.1029/2004GL022168
Sokolovskiy, S., Y.-H. Kuo, C. Rocken, W. S. Schreiner, D. Hunt, and R. A.
Anthes (2006), Monitoring the atmospheric boundary layer by GPS radio
occultation signals recorded in the open-loop mode, Geophys. Res. Lett.,
33, L12813, doi:10.1029/2006GL025955.
Sokolovskiy, S., C. Rocken, D. H. Lenschow, Y.-H. Kuo, R. A. Anthes,
W. S. Schreiner, and D. C. Hunt (2007), Observing the moist troposphere
with radio occultation signals from COSMIC, Geophys. Res. Lett., 34,
house Basha and M. V. Ratnam (2009): Identification of atmospheric boundary layer height over a tropical station using high resolution radiosonde refractivity profiles: Comparison with GPS radio occultation measurements, J. Geophys. Res., 114, D16101, doi:10.1029/2008JD011692
robust method to determine global distribution of atmospheric boundary layer top from COSMIC GPS RO measurements, Atmos. Sci. Let., DOI: 10.1002/asl.277.