Automating Detection of the Planetary Boundary Layer in Aerosol Lidar Soundings Virginia Sawyer Advisor: Dr. Judd Welton, NASA-GSFC

Planetary Boundary Layer The transition between well-mixed surface air and the free atmosphere aloft. Usually maintained by a temperature inversion, which is buoyantly stable. Important to air quality and climate modeling.

Entrainment Zone Frequently, the boundary layer is best expressed as a zone rather than a single height. This is especially true because of Deep inversions with stably-stratified layers Kelvin-Helmholz waves

LIDAR MPLNET is composed of micro pulse lidar sites, co-located with sunphotometers in the AERONET project, to provide continuous long-term data on atmospheric structure (primarily aerosol and clouds). Network includes sites from NASA and from partners around the world. The CALIPSO satellite contains a lidar and a wide field of view camera to study aerosol and clouds. CALIPSO is part of the A-train constellation in NASA’s Earth Observing System. 532 nm 523 or 527 nm

Wavelet Covariance Transform Haar Function a = width of entrainment zone b = PBL height Brooks, I.M., Finding Boundary Layer Top: Application of a Wavelet Covariance Transform to Lidar Backscatter Profiles. J. Atmos. Oceanic Technol. 20,

Nighttime stable layers Kelvin-Helmholz waves Convective clouds MPLNET Goddard, 5/3/2001 Elevated aerosol entrained by the PBL during the day

Maximum of W f (a,b) follows cloud deck

Program revised to follow aerosol layer below

Particulate from South America? CALIPSO 3:10-3:15 UTC 9/21/06

Himalayas CALIPSO 20:30-20:37 UTC 1/1/07

Conclusions The wavelet covariance transform can be used to detect the planetary boundary layer in aerosol lidar soundings. Modifications to the algorithm filter out high clouds and elevated aerosols, and speed up calculations. Entrainment zone depth is more difficult to find in the relatively noisy CALIPSO data.

Thanks Dr. Judd Welton, NASA Larry Belcher, UMBC Stephen Palm, SSAI Research & Discover