Bio-optical drifters; Scales of variability of chlorophyll and fluorescence

Both the California Current System and the Antarctic Polar Front are characterized by mesoscale variability and meandering jets. These meanders lead to regions of strong vertical motion, on the order of several lens of meters per day. To study physical and biological scales of variability in these two systems, near-surface drifters were released in these two environments; twenty-six in the California Current and five in the Polar Front. Each drifter was equipped with a spectroradiometer to measure upwelled radiance at the SeaWiFS wavelengths as well as at 683 nm. A temperature system was also included. Data were relayed to shore via satellite. These data were converted into biological quantities, including chlorophyll and an apparent quantum yield of fluorescence. Decorrelation rime scales were calculated and compared with corresponding statistics of the physical environment. Time scales for all variables increased as the drifters moved from nearshore to offshore. The scales associated with temperature and chlorophyll were similar nearshore, but increased more rapidly offshore for temperature. This suggests that the processes regulating the distribution of temperature and chlorophyll are similar in the nearshore region and significantly differ offshore.