Guidelines to compare datasets


    You wish to compare datasets derived either from satellite imagery, numerical weather models and/or in-situ measurements? Here are a non-exhaustive list of elements that is mandatory to know before any activity of comparison.

Parameters Sub-parameters or potential values Comments
Geographical coordinates Latitude, Longitude and Altitude With at least four digits after comma. Altitude can be retrieved using the altitude portlet to get altitude from SRTM database. It helps also to confirm the site selection is correct.
Time period date_begin, date_end No big issue in general with this info
Time reference UT ? LT? Summer Saving time or not? Help for time references
Hypothesis of integration Instantaneous or integrated Very important parameter, that can lead to huge errors if not considered
The given instant corresponds to beginning, middle, or end of interval? Idem
Units W/m2, Wh/m2, µmol/m2/s... Very important, permit to confirm or not previous elements
Value for missing data? 65535, NaN, -1, "NA", ... Detect these specific values and set it to an adequate value in your coding environment (e.g. NaN in Matlab)
type of Instruments name, spectral response,...  


Top of page