Ultraviolet Radiation and Bio-optics in Crater Lake, Oregon, 2005
Proxies for Kd,UV
Least squares linear regressions were used to develop proxy Kd,UV values from measured ZSD (using 1/ZSD), Kd,blue, and Kd,380 averaged over the 0–40 m or the Secchi depth. To develop an empirical model for Kd,380 based on chlorophyl-a fluorescence and cp660 we used trial and error to adjust two parameters to minimize residuals in comparison with Kd,380 determined from LI-1800uw spectral scans. To compute Kd,320 and Kd,380 from 1/ZSD, Kd,blue was computed as an intermediate step. When historical data were measured over a different range of depths than 0–40 m we used recent patterns of Kd versus depth to calculate adjusted values.