Principal Investigator
Mike Foster, Space Science and Engineering Center, University of Wisconsin - Madison
Citation
Cite dataset when used as a source. See the dataset's landing page for citation details at doi:10.7289/V5X9287S.
Data Access
Information
Documentation
Technical Note
The AVHRR instrument does not have an onboard calibration system for the 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 the calibration for a file is unlikely to change the 'preliminary' is removed, and it is determined to be in its final version. The 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, National Centers for Environmental Information (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 for the purposes of tracking the specific data used for an application or in case users believe even minor differences in calibration may affect their results.