Colloquium: Prof. Yongxiang Hu, NASA Langley

TITLE: CALIPSO Cloud, Ocean and Land Measurements  ABSTRACT: While most people consider CALIPSO primarily a satellite for aerosol measurements, CALIPSO does provide unique cloud measurements. It can also measure ocean and land surface. CALIPSO provides accurate cloud thermodynamic phase discrimination. Water cloud extinction coefficient and droplet number concentration can also be derived from the lidar measurements. One of the findings from CALIPSO cloud phase statistics is that there are a lot more supercooled liquid water clouds than we previously thought. Supercooled liquid water clouds are found very frequently in the Southern Ocean region. For the same amount of water content, water clouds reflect a lot more solar infrared light and have larger optical depths comparing with ice clouds. This may explain why modeled cloud albedo over the Southern Oceans are always lower than CERES observations. CALIPSO also measures phytoplankton backscatter and ocean surface wind speed. CALIPSO’s laser light is linearly polarized. CALIPSO’s 532nm (green light) cross polarization channel measurements include several vertical range bins into the ocean and can capture phytoplankton backscatter. CALIPSO also measures mean square wave slopes of ocean surface. This talk will introduce these measurements. Although CALIPSO samples at 30 meter vertical resolution, we can estimate the surface height at a much higher resolution using a super-resolution concept. I will introduce this concept and the data product as well.