Re: How does the rainforests regular rainfall in turn affect the global clima

I am not sure that I understand your question.  In general rainfall in 
rainforests is not regular but very seasonal.  Most rainforests have a 
rainy season and a drier or less rainy season.  The rain occurs largely 
because of the large amounts of energy available to evaporate water into 
the atmosphere. This in turn increase cloudiness in the tropics which 
influences the global albedo (reflectivity). Clouds reflect solar energy but 
they alo hold in thermal energy so the effect on the temperature is largely 
a function of the height of the clouds.
All tropical forests are not rain forests and in fact the area of seasonal 
and dry forests (or what would be dry forests if they had not been 
converted to rangeland) probably exceed the area of rainforest. If we could 
alter the amount or timing of rainfall in tropical forests it would most 
likely happen by a cooling of the earth.  Or to put it another way, if we 
cooled the earth, then the amount and timing of rainfall would probably 
decrease on average.  This is simply because more heat causes more 
evapotranspiration and vice versa.