The instruments used in this study are the University of Wisconsin High Spectral Resolution Lidar (HSRL), the University of Wisconsin Volume Imaging Lidar (VIL), and the VISSR (Visible and Infrared Spin Scan Radiometer) Atmospheric Sounder (VAS) situated on the GOES satellite. These instruments were part of CRSPE (University of Wisconsin--Madison Cirrus Remote Sensing Pilot Experiment) (Ackerman et al. (1993)).