QUESTION:

Occasionally when I return to recalculate a model (specifically with hourly temperature) I get quite different results for some zones without being aware of having changed any parameters - any suggestions what is happening here ? (classmates were describing similar problems)

ANSWER:

Could be any number of reasons. However the most likely thing is, it may be that you are not doing (or letting ECOTECT) do an inter-zonal adjacency calc when it needs to, so that when one is eventually done several previous changes take effect in the one calc. Difficult to say for certain though without watching what you are doing