Novel Spectrograph/Radiometer for Cloud Top Height Measurement Using Three Complementary Techniques

A proof-of-concept (POC) instrument system to measure cloud top height from space using three complementary techniques is presented. These techniques use measurements of: (1) thermal infrared (IR); (2) molecular oxygen 'A' band absorption; and (3) filling-in of Fraunhofer lines (the Ring effect), respectively. Combining three techniques is achieved with a single grating spectrograph with bandpass and order sorting filters by measuring I I jim radiation from the zeroth order of the grating for the IR, 750-780 nm radiation from the first order for the 'A' band absorption, and 390-400 mn radiation from the second order for the Ca K and H Fraunhofer line filling-in effect. The POC system and its measurement results with the POC system are described.