USE AND EVALUATION OF BIOLOGICAL SPECTRAL UV WEIGHTING FUNCTIONS FOR THE OZONE REDUCTION ISSUE - Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models - page 74

Figure 5. Relative RAF and enhancement errors as a function of ozone reduction for field UV
supplementation experiments under temperate-latitude conditions in the summer (40° latitude at the summer
solstice). The scenario for these errors is that the RAF values and the enhancements were calculated following
the generalized plant action spectrum when the DNA damage spectrum was indeed more appropriate. From
Caldwell et al. [11].
The enhancement error is in the opposite direction from the RAF error in this
scenario (Figure 5). Even at low levels of simulated ozone reduction, the error is
appreciable. This error increases at higher ozone depletion levels, but not in the same
trajectory as the RAF error. The so-called "enhancement error'' arises because the
spectral composition of UV coming from the lamps is different from that of sunlight
with ozone reduction; it contains proportionately more shortwave UV-B radiation [11].
(If the lamp could supply an increment of UV-B radiation with exactly the same
wavelength composition as the increased solar UV-B radiation resulting from ozone
reduction, then this "enhancement error'' would not exist.) Thus, the shape of BSWF's
are critical when they are used in experiments and in experimental simulations of solar
radiation with ozone reduction. If the two BSWF in Figure 2 had been used in
portraying this scenario of RAF and enhancement errors, the errors would be much
larger.