Combined lidar-radar remote sensing: Initial results from CRYSTAL-FACE

In the near future, NASA plans to fly satellites carrying a two-wavelength polarization lidar and a 94-GHz cloud profiling radar in formation to provide complete global profiling of cloud and aerosol properties. The Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) field campaign, conducted during July 2002, provided the first high-altitude collocated measurements from lidar and cloud profiling radar to simulate these spaceborne sensors. The lidar and radar provide complementary measurements with varying degrees of vertical measurement overlap within cloud layers. This paper presents initial results of the combined airborne lidar-radar measurements during CRSYTAL-FACE. A comparison of instrument sensitivity is presented within the context of particular CRYSTAL-FACE observations. It was determined that optically thin cirrus clouds are frequently missed by the radar but are easily profiled with the lidar. In contrast, optically thick clouds and convective cores quickly extinguish the lidar signal but are easily probed with the radar. Results are presented to quantify the portion of atmospheric features sensed independently by each instrument and the portion sensed simultaneously by the two instruments. To capture some element of varying atmospheric characteristics, two cases are analyzed, one with convective systems and one having synoptic cirrus and considerable clear air. The two cases show quite different results, primarily due to differences in cloud microphysics.