A method for estimating sea surface nitrate concentrations from remotely sensed SST and chlorophyll a-a case study for the north Pacific Ocean using OCTS/ADEOS data

Proposes a method to estimate sea surface nitrate (N) from space using satellite measurements of sea surface temperature (SST) and chlorophyll a (chl a). The procedure relies on empirical relationships between shipboard measurements of N and its predictor variables, temperature (T) and chl a in surface and near surface waters. Although N appears to be controlled primarily by T, the addition of the biological variable chl a helps improve N prediction by reducing local and regional differences in the character of the temperature-nitrate (T-N) relationship. The authors have applied these empirical algorithms to SST and chl a data from the Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observation Satellite (ADEOS). The results clearly suggest that measurements of SST and chl a now possible by modern-day ocean satellites could be exploited usefully to extend the resolution of shipboard N measurements over large spatial and temporal scales. Systematic errors in estimates of N that could result from errors in satellite estimates of SST and chl a are examined through sensitivity analyses.