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Rawlins County Kansas | You are exactly correct concerning planting dates. Also earlier harvest (i.e, in wheat belt) will skew the comparisons.
These data (both at KARS and NASS) are multi-date composites (14 day). That many days are needed to ensure cloud-free composites. A consequence of this wide time period is that it is possible that two pixels side by side might contain information that is 14 days different from one another.
For drought monitoring it is typically more useful to look at the natural vegetation (forests, grasslands, riparian areas, etc) rather than the agriculture vegetation. The natural environment is a very good and consistent indicator of overall current climate conditions and isn't subject to the problems associated with crop land data (differences in planting date, hybrid, crop type, rotation, etc).
I do have a question for you Illinois guys. A lower greennes pattern has been present south of Chicago that extends down into EC Illinois. What is this? Late planting, more soybeans or are you really seeing poorer conditions on the ground?
Thanks,
Diet | |
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Foliage density satellite images...
