Validation of cloud property retrievals from MTSAT-1R imagery using MODIS observations
Abstract:A cloud property retrieval algorithm optimized for five channels (centred at 0.6, 3.7, 6.7, 10.8, and 12.0 μm) has been explored for application to onboard meteorological radiometers on geostationary satellites; however, its validity remains to be established. Here, we present validation results for the cloud properties retrieved by the developed algorithm from the full-disk imagery of the Multi-functional Transport Satellite (MTSAT-1R) for August 2006. The considered cloud properties include cloud phase (CP), cloud optical thickness (COT), effective radius (ER) and cloud top pressure (CTP). Their one-month averages, daily variations, and respective collocated values are compared with the Moderate Resolution Imaging Spectroradiometer cloud data. Our validation results show that an additional 6.7 μm brightness temperature test in CP retrieval identifies water and ice phases that may be overlooked in the 10.8- and 12.0-μm bands. Our method to extract cloud-reflected radiances at the 0.6- and 3.7-μm bands contributes to the accuracy of the COT for values between 5 and 60, and the ER for values less than 40 μm. Estimating high-cloud top pressure from the radiance ratio in the 6.7- and 10.8-μm bands remarkably reduces (by up to 70%) large uncertainties in the CTP, which may be found in the presence of high thin cirrus clouds.
Document Type: Research Article
Affiliations: 1: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA,School of Earth and Environmental Sciences, Seoul National University, Seoul, Korea 2: School of Earth and Environmental Sciences, Seoul National University, Seoul, Korea
Publication date: 2009-01-01