Short revisit cycle and temporal sampling

There is a somewhat recent trend in the development of new remote sensing satellite systems toward short revisit cycle (that is a high temporal resolution). Future systems such as VenĀµs or the Sentinels will be providing images of a given site every 2 to 5 days.
One may wonder which real applications may need this high temporal resolution. Although there are some applications which need it, it is also true that most of the applications foreseen for these systems will work with fewer images per period of time.
However, there are several point to take into account when we think about temporal sampling. First of all, at least for optical systems, the cloud cover can make unusable a high percentage of the images which are acquired by the sensors. Second, even if the mean number of images per year for a given application may be low, some of the applications may need a higher temporal resolution during some periods of the year (example of the phenology of crops). And the fact is that flight mechanics make easier to keep the same orbit all over the life span of a satellite.
And last, but not least, many new applications can emerge when this kind of data is made available to scientists.
In the coming versions of the Orfeo Toolbox, specific tools for image time series will be made available in order to help the users of this kind of data to use them efficiently.