(a) For each of the continent, estimate the mean annual potential evapotranspiration using net

radiation. You can estimate an approximate annual extraterrestrial radiation by using the

Figure 3-6 of Dingman [2002] for the boundary latitudes of each continent and roughly

average the radiation within each continent. (Please use rough estimates or this could easily

turn into a major project..!)

(b) Plot the Zhang et al [2001] equation using w=0.5, 1, and 2 for a given range of aridity index

values (i.e., aridity index=0, 0.5, 1, ..., 5). Now calculate the aridity index for each continent

and plot continental E/P and aridity index on the same plot, and prepare a separate plot for

R/P and aridity index. Do you see a climatic signature on continental evapotranspiration and

runoff?