Abstract
The Edition 2 (Ed2) cloud property retrieval algorithm system was upgraded and applied to the MODerate-resolution Imaging Spectroradiometer (MODIS) data for the Clouds and the Earth's Radiant Energy System (CERES) Edition 4 (Ed4) products. New calibrations for solar channels and the use of the 1.24-μm channel for cloud optical depth (COD) over snow improve the daytime consistency between Terra and Aqua MODIS retrievals. Use of additional spectral channels and revised logic enhanced the cloud-top phase retrieval accuracy. A new ice crystal reflectance model and a CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -channel algorithm retrieved higher ice clouds, while a new regional lapse rate technique produced more accurate water cloud heights than in Ed2. Ice cloud base heights are more accurate due to a new cloud thickness parameterization. Overall, CODs increased, especially over the polar (PO) regions. The mean particle sizes increased slightly for water clouds, but more so for ice clouds in the PO areas. New experimental parameters introduced in Ed4 are limited in utility, but will be revised for the next CERES edition. As part of the Ed4 retrieval evaluation, the average properties are compared with those from other algorithms and the differences between individual reference data and matched Ed4 retrievals are explored. Part II of this article provides a comprehensive, objective evaluation of selected parameters. More accurate interpretation of the CERES radiation measurements has resulted from the use of the Ed4 cloud properties.
Highlights
T HE Clouds and the Earth’s Radiant Energy System (CERES) Project [1] has been making global measurements of the earth’s radiative energy budget and cloud properties from Terra (1030 LT equatorial crossing time) and Aqua (1330 LT equatorial crossing time) sinceMarch 2000 and July 2002, respectively
Cloud fraction weighting was not used for the Edition 2 (Ed2) averages reported in [50], so the results are different in many cases
A significant number of changes have been made to various components of the CERES cloud retrieval algorithms in Edition 4 (Ed4)
Summary
T HE CERES Project [1] has been making global measurements of the earth’s radiative energy budget and cloud properties from Terra (1030 LT equatorial crossing time) and Aqua (1330 LT equatorial crossing time) sinceMarch 2000 and July 2002, respectively. It branches into two sequences of subsystems: 1) a mimic of an older simpler analysis system relying only on the scanner LW and SW radiance observations and 2) the CERES standard approach, a more complex methodology that incorporates radiances and cloud and aerosol properties from a collocated conterminous satellite imager (MODIS for this article) and geostationary satellite (GEOsat) data that cover the entire diurnal cycle [25], [26] The former methodology determines only the TOA fluxes using older ADMs to convert radiances to fluxes (see [27]) and to assist interpolation of the fluxes over the diurnal cycle to estimate the entire radiation budget [28]. But less comprehensive changes having minor effects on particular subsystems are identified by appending a letter to the Edition number
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
