Table 1 The variability in Nd explained by each predictor.

R2 is given in percent for both unweighted calculations and a robust calculation using bi-square weights, using a bias-corrected Nd data set. Spatial R2 values are calculated by applying the same regression procedure and using bi-square weights, but using time-averaged values of bias-corrected Nd for the period September through April. Additional notes following asterisks give the R2 values calculated using a 9-year monthly climatology of MODIS Nd including retrievals at all SZAs. Uncertainties are the SDs of estimates of R2 from 10-fold cross-validation, repeated 10 times.

R2 (%)R2 (robust, %)Spatial R2
OMF24 ± 535 ± 10*(14 ± 4, 16 ± 4)33 ± 22
SO445 ± 748 ± 7*(20 ± 6, 23 ± 7)48 ± 24
OMF + SO449 ± 553 ± 6*(22 ± 6, 28 ± 7)53 ± 22
OMF + SO4 + SS + wind49 ± 653 ± 557 ± 20
OMF + SO4 + SS49 ± 653 ± 758 ± 22
SS11 ± 49 ± 416 ± 17
SST4 ± 33 ± 213 ± 13
Wind14 ± 413 ± 318 ± 18
SS + wind14 ± 413 ± 414 ± 13
SST + wind + SS16 ± 517 ± 416 ± 13
Chl-a20 ± 735 ± 1355 ± 24
DMS15 ± 619 ± 612 ± 11