Lidar/Laser Sounders
CPL
The Cloud Physics Lidar (CPL) (successor to the Cloud Lidar System is an airborne lidar system designed specifically for studying clouds and aerosols using the ER-2 High Altitude Aircraft. Because the ER-2 typically flies at 65,000 feet (20 km), its instruments are above 94% of the earth's atmosphere, thereby allowing ER-2 instruments to function as spaceborne instrument simulators. The Cloud Physics Lidar provides a unique tool for atmospheric profiling and is sufficiently small and low cost to include in multiple instrument missions. The Cloud Physics Lidar flies on the ER-2 along with other instruments and is typically located in the forward section of the left wing superpod. A window in the bottom of the superpod allows the instrument to look directly at nadir (this is a non-scanning system). The Cloud Physics Lidar provides a complete battery of cloud physics information. Data products include: Cloud profiling with 30 m vertical and 200 m horizontal resolution at 1064 nm, 532 nm, and 355 nm, providing cloud location and internal backscatter structure. Aerosol, boundary layer, and smoke plume profiling at all three wavelengths. Depolarization ratio to determine the phase (e.g., ice or water) of clouds using the 1064 nm output. Cloud particle size determined from a multiple field-of-view measurement using the 532 nm output (off-nadir multiple scattering detection). Direct determination of the optical depth of cirrus clouds (up to ~OD 3) using the 355 nm output. The CPL provides information to permit a comprehensive analysis of radiative and optical properties of optically thin clouds. To determine the effects of particulate layers on the radiative budget of the earth-atmosphere system certain information about the details of the layer and its constituents is required. The effect of clouds is often referred to as cloud radiative forcing. Cloud radiative forcing, in general, is the alteration that the presence of clouds has on the energy budget. The information required to compute the radiative forcing includes the vertical distribution of short wave cross section, a parameter that the CPL provides up to the limits of optical signal attenuation. Additional information available at "http://cpl.gsfc.nasa.gov/" [Summary provided by NASA]