Chaos, consternation and CALIPSO calibration: new strategies for calibrating the CALIOP 1064 nm channel

The very low signal-to-noise ratios of the 1064 nm CALIOP molecular backscatter signal make it effec-tively impossible to employ the "clear air" normali-zation technique typically used to calibrate elastic back-scatter lidars. The CALIPSO mission has thus chosen to cross-calibrate their 1064 nm measurements with respect to the 532 nm data using the two-wavelength backscatter from cirrus clouds. In this paper we discuss several known issues in the version 3 CALIOP 1064 nm calibration procedure, and describe the strategies that will be employed in the version 4 data release to sumount these problems.