A recently developed instrument, named Nephelo, operates 7 infrared sensors, each with a 6-degree field of view, and spectral range 8-14 mm. The sensors are mounted on a semi-circular portico at angles 0, 12, 24, 36, 48, 60 and 72. A "hemispherical" mosaic of 181 brightness temperature measurements centered on the zenith is obtained by the rotation of the semi-circular portico around the vertical axis, performing 30 scans, every 12° from 0° (North) to 348°. We suggest an algorithm that utilizes the brightness temperatures from the Nephelo given the precipitable water vapor amounts and vertical profiles of the thermodynamic state of the atmosphere from independent measurements. The algorithm estimates the cloud amount, maps out the spatial distribution of cloud field and determines the vertical distribution of the clouds. The algorithm is tested through inter-comparison with well studied ground-based and satellite retrieval techniques developed in ARM and NASA. Initial analyses show good cloud amount assessment and spatial mapping abilities. The vertical distribution understanding is currently limited, however, the amounts of low, middle and high clouds could be determined and studied further to improve the algorithm.
Revised: April 29, 2011 |
Published: September 15, 2004
Citation
Genkova I.S., C.N. Long, T. Besnard, and D. Gillotay. 2004.Assessing Cloud Spatial and Vertical Distribution with Cloud Infrared Radiometer CIR-7. In Proceedings of the SPIE: Remote Sensing of Clouds and Atmosphere IX, September 13-15, 2004, Maspalomas, Spain, edited by A Comeron, MR Carleer, RH Picard, NI Sifakis, 5571. Bellingham, Washington:S.P.I.E.PNNL-SA-44214.doi:10.1117/12.564234