What do values of 14 mean in “i_LayHgt_Flag” (GLA08)?
Values of 1-13 in “i_LayHgt_Flag” describe confidence levels of the quality of the height retrieval; “1” indicating very low confidence and “13” very high. A value of “14” indicates bad PBL height retrieval because of either bad input data or a mistake in the retrieval algorithm. The PBL quality flag is computed from the ratio of the average signal (attenuated, calibrated backscatter) within the PBL to the average signal 500 m above the PBL. Normally, the backscatter increases significantly at the top of the PBL and remains higher within the PBL unless it is attenuated by a cloud, extremely dense dust, or smoke; thus, the quality flag is proportional to the magnitude of the gradient of scattering at the PBL top. The larger this gradient, the easier it is to find the PBL top and hence the higher confidence in its detection.
