The Bowen ratio of the natural vegetation is about β≈11, but much lower in the cultivated and temporally irrigated area along the valley floor. A typical value of the Bowen ratio of a field covered by potatoes is β≈2.5 after harvesting or during dry periods and is β≈0.7 to 22230dc2b0604c2"" title=""Click to view the MathML source"">1 after irrigation events or precipitation.
For an area with natural vegetation, the annual accumulated evapo-transpiration reaches 65 mm yr−1, which is 65 % of the mean annual precipitation and 3.5 % of the equivalent net radiation Rn/L. For the cultivated fields along the valley floor, the annual accumulated evapo-transpiration reaches 750 mm yr−1, which is 40 % of the equivalent net radiation, Rn/L, and about 100 % of the sum of estimated irrigation and mean annual precipitation (I+P). The annual nocturnal dew deposition is about 5–10 mm yr−1 and, thus, serves as an additional water source for natural vegetation, especially during dry years.