By using such data we may distort the effects of processes that are far from linear. However, at this more detailed scale we find that other parameters, such as soil heat flux, need to be considered. The current trend of introducing biosphere data among the earth surface processes relevant to global atmospheric circulation results in a need for information about the response times of vegetation. At one extreme the response time of stomata to changing levels of radiation is normally rapid, within tens of minutes. However, it is known that the stomata of drought stressed plants recover their ability to open over a period of several days once water is readily available.
High temperatures can also result in longlasting responses.
There is a danger when working at one scale to become prejudiced against extrapolation of results and even concepts to another scale. Thus descriptions of hydrological processes that form the building blocks of physical hydrology are often abandoned in favour of black box models at the larger scale. However, the approaches to hydrology, in its widest sense, need not be contradictory at different scales. The apparent contradiction arises because when there are enough ordered elements or events combined in a more or less random manner, stochastic methods can be used at the larger scale that would be totally inappropriate at the smaller scale. This demonstrates that possibly the best approach in the future for transfer between scales in hydrology is to interpolate from both larger and smaller scales to the required intermediate scale.