The Cloud Physics Lidar, or CPL, is a backscatter lidar designed to operate simultaneously at 3 wavelengths: 1064, 532, and 355 nm. The purpose of the CPL is to provide multi-wavelength measurements of cirrus, subvisual cirrus, and aerosols with high temporal and spatial resolution. Figure 1 shows the entire CPL package in flight configuration. The CPL utilizes state-of-the-art technology with a high repetition rate, low pulse energy laser and photon-counting detection. Vertical resolution of the CPL measurements is fixed at 30 m; horizontal resolution can vary but is typically about 200 m. The CPL fundamentally measures range-resolved profiles of volume 180-degree backscatter coefficients. From the fundamental measurement, various data products are derived, including: time-height crosssection images; cloud and aerosol layer boundaries; optical depth for clouds, aerosol layers, and planetary boundary layer (PBL); and extinction profiles. The CPL was designed to fly on the NASA ER-2 aircraft but is adaptable to other platforms. Because the ER-2 typically flies at about 65,000 feet (20 km), onboard instruments are above 94% of the earth’s atmosphere, allowing ER-2 instruments to function as spaceborne instrument simulators. The ER-2 provides a unique platform for atmospheric profiling, particularly for active remote sensing instruments such as lidar, because the spatial coverage attainable by the ER-2 permits studies of aerosol properties across wide regions. Lidar profiling from the ER-2 platform is especially valuable because the cloud height structure, up to the limit of signal attenuation, is unambiguously measured.
Cloud Physics Lidar
Instrument Type
Measurements
Aircraft
Recent Missions
Point(s) of Contact
(POC; PI),
(Prev PI)
Range of Measurement
Vertical profile
Instrument Pointing
Nadir (directly downwards)
Measurement Sampling Rate
1.00 Hz
Vertical Resolution
30.00 m
Weight
171.00 kg
Location
Forward section of the wing superpod on the ER-2.
Notes
50/25/50 microJ per pulse
Mission-Specific Writeups
Document
TRL
9
Website
Publications
Vaughan, M., et al. (2009), On the spectral dependence of backscatter from cirrus clouds: an assessment of CALIOP's 1064 nm calibration using Cloud Physics Lidar measurements, Atmos. Chem. Phys.(submitted).
McGill, M., et al. (2007), Airborne validation of spatial properties measured by the CALIPSO lidar, J. Geophys. Res., 112, D20201, doi:10.1029/2007JD008768.
McGill, M., et al. (2004), Combined lidar-radar remote sensing: Initial results from CRYSTAL-FACE, J. Geophys. Res., 109, D07203, doi:10.1029/2003JD004030.
Midzak, N., et al. (2022), Constrained Retrievals of Aerosol Optical Properties Using Combined Lidar and Imager Measurements During the FIREX-AQ Campaign, Front. Remote Sens., 3, 818605, doi:10.3389/frsen.2022.818605.
Midzak, N., et al. (2020), A Classification of Ice Crystal Habits Using Combined Lidar and Scanning Polarimeter Observations during the SEAC4RS Campaign, J. Atmos. Oceanic Technol., 37, 2185-2196, doi:10.1175/JTECH-D-20-0037.1.