Moisture recycling

In hydrology, moisture recycling or precipitation recycling refer to the process by which a portion of the precipitated water that evapotranspired from a given area contributes to the precipitation over the same area. Moisture recycling is thus a component of the hydrologic cycle. The ratio of the locally derived precipitation ($$P_{L}$$) to total precipitation ($$P$$) is known as the recycling ratio, $$\rho$$: $$\rho = P_{L}/P$$.

The recycling ratio is a diagnostic measure of the potential for interactions between land surface hydrology and regional climate. Land use changes, such as deforestation or agricultural intensification, have the potential to change the amount of precipitation that falls in a region. The recycling ratio for the entire world is one, and for a single point is zero. Estimates for the recycling ratio for the Amazon basin range from 24% to 56%, and for the Mississippi basin from 21% to 24%.