In GLA09 (GLAH09), is there a cloud bottom for every cloud top? How do you match them?
For every top of layer given, there is definitely a bottom of layer given in the same corresponding location in the vector. The tops and bottoms vectors are ordered top-down for each channel (532 nm or 1064 nm) independently. Thus, if Cld_top and Cld_bot are the 10-element arrays that hold the top and bottom heights of the cloud layers, then Cld_top(1) is the height of the highest cloud layer and Cld_bot(1) is the height of the bottom of the same cloud layer. Cld_top(2) and Cld_bot(2) are then the top and bottom heights of the next layer down (if there is one detected). A critical fact to remember when using GLA09 (GLAH09) is that the vectors holding the tops and bottoms of the layers are used for both 532 nm and 1064 nm detection results. The use flags must be decoded to determine which channel was used to find a particular layer. As an example, suppose that the cloud availability flag (this specifies the total number (532+1064) of cloud layers present) has a value of 5 and the use flags corresponding to the five layers are 0,0,0,1,1. This does not mean that five cloud layers were detected, but rather that Cld_top(1....5) and Cld_bot(1....5) have defined values, and the first three layers (use flag = 0) were obtained from the 532 channel, and the last two layers were obtained from the 1064 nm channel. Further, the layers detected with the 532 nm channel will always precede those detected by the 1064 nm channel (unless of course the 532 channel was inoperative in which case only layers detected by the 1064 nm channel will be present).