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Global seasonal variations of midday planetary boundary layer depth from CALIPSO space‐borne LIDAR
Author(s) -
McGrathSpangler Erica L.,
Denning A. Scott
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50198
Subject(s) - lidar , environmental science , climatology , planetary boundary layer , seasonality , atmospheric sciences , middle latitudes , monsoon , satellite , intertropical convergence zone , geology , meteorology , geography , remote sensing , precipitation , mathematics , engineering , aerospace engineering , turbulence , statistics
We present a new global analysis of the depth of the planetary boundary layer (PBL) and consider regional variations throughout the year. PBL depth is estimated from the vertical variance of CALIPSO space‐borne LIDAR backscatter associated with aerosol and shallow clouds during midday satellite overpasses and is only retrieved in the absence of optically thick clouds. The resulting analysis of over 100 million retrievals per year is therefore only a sample with higher frequency over deserts and other regions of strong subsidence, and lower frequency over regions of deep convection such as the ITCZ, tropical rainforests, and the Asian Monsoon. The mean of sampled PBL depths ranges from 500 m over cold oceans to more than 3000 m over hot deserts. The seasonal cycle of analyzed PBL depth is stronger over land than over water, and seasonality over land and midlatitude oceans is of opposite sign. Wintertime storm tracks and stratocumulus regions over subtropical oceans are prominent features of the analysis. Although evaluation of the new analysis is difficult due to previous sparse sampling by other methods, comparison of LIDAR‐retrieved PBL depth with data collected by commercial aircraft generally shows good agreement.