Richard, rather than me trying to understand the physics involved in UVI derivation so as to calculate safe and effective UVB doses for my skin for different elevations of the sun, I will reformulate my question starting with a statement: Through repeated skin cancer checks and blood tests during the past 9 years I have established how many minutes of sunshine exposure my body requires to receive a safe and effective UVB dose when NIWA’s real time UVI at my location is between 9 and 10. Am I correct in assuming that I should double the time of sunshine exposure to receive the same safe and effective UVB dose when NIWA’s real time UVI is between 4 and 5 at my location, or is UVB intensity not a simple linear function of real time UVI?
Richard, rather than me trying to understand the physics involved in UVI derivation so as to calculate safe and effective UVB doses for my skin for different elevations of the sun, I will reformulate my question starting with a statement: Through repeated skin cancer checks and blood tests during the past 9 years I have established how many minutes of sunshine exposure my body requires to receive a safe and effective UVB dose when NIWA’s real time UVI at my location is between 9 and 10. Am I correct in assuming that I should double the time of sunshine exposure to receive the same safe and effective UVB dose when NIWA’s real time UVI is between 4 and 5 at my location, or is UVB intensity not a simple linear function of real time UVI?