HICRU applies the widely used threshold method to the so-calledPolarization Monitoring Devices (PMDs) with higher spatialresolution compared to the channels used for trace gas retrievals.Cloud retrieval and in particular the identification of cloud freepixels is improved by HICRU through a sophisticated, iterativeretrieval of the thresholds which takes their dependency ondifferent instrumental and geometrical parameters into account.The lower thresholds, which represent the surface albedo andstrongly affect the results of the algorithm, are retrievedaccurately through a four stage classification scheme using imagesequence analysis.
The design and the results of the algorithm applied to GOME dataare described and compared to several other cloud algorithms forGOME. The differences to other cloud algorithms are discussed withrespect to the particular characteristics of the algorithms.
