To help the project receive continued support, updates, and improvement, tell us how you use PATMOS-x Cloud Properties CDR data by completing our optional User Registration Form.
Technical Note
The AVHRR instrument does not have an onboard calibration system for solar reflectance channels (0.63-, 0.86- and 1.6-microns). As a result, the most recent data relies on an extrapolation of the existing calibration (Heidinger et al. 2010). The most recent data contain the word 'preliminary' in the file name to indicate that the values may change slightly as new calibration coefficients become available. Once a file is calibrated, 'preliminary' is removed. Calibration process is performed approximately once a year at the University of Wisconsin - Madison. As a result, there is often more than one version of 'preliminary' files for the most recent data. To avoid confusion NCEI archives only the first 'preliminary' version of data until the final version is available. However, the Climate Data Portal at the University of Wisconsin - Madison serves the 'preliminary' version of the data with the most recent calibration available. While the differences tend to be quite small, we include this note to track the specific data used for an application, or in case minor differences in calibration may affect your results.