[1] Colored dissolved organic matter (CDOM), also referred to as gelbstoff, gilvin, or yellow matter, has long been known to be an important component of the optical properties of coastal and estuarine environments. However, an understanding of the processes regulating its global distribution and variability, its relationship to the total pool of dissolved organic carbon (DOC), and its influence on light availability remain largely unexplored. Satellite imagery from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) is used to characterize the global distribution of light absorption due to colored detrital and dissolved materials (CDM). The quantity CDM is considered as it is not yet possible to differentiate CDOM and detrital particulate absorption from ocean color spectra on a routine basis. Nonetheless, analysis of an extensive field data set indicates that detrital particulates make only a small contribution to CDM. A comparison of coincident field observations of CDM with SeaWiFS retrievals shows good agreement, indicating that the present procedures perform well. To first order, the basin-scale CDM distribution reflects patterns of wind-driven vertical circulation of the gyres modulated by a meridional trend of increasing CDM toward higher latitudes. The global CDM distribution appears regulated by a coupling of biological, photochemical, and physical oceanographic processes all acting on a local scale, and greater than 50% of blue light absorption is controlled by CDM. Significant differences in both CDM concentration and its contribution to blue light absorption are found spatially among the major ocean basins and temporally on variety of timescales. Significant impacts of riverine discharges can be discerned, although their effects are largely localized. Basin-scale distributions of CDM and DOC are largely unrelated, indicating that CDM is a small and highly variable fraction of the global DOC pool. This first view of the global CDM distribution opens many new doors for the quantification of global marine photoprocesses using satellite ocean color data.

Variability in the optical particle backscattering coefficient (b bp ) is investigated in oceanic waters from two sites, namely the BOUée pour l'acquiSition d'une Série Optique à Long termE site in the northwestern Mediterranean Sea and the Plumes and Blooms stations in the Santa Barbara Channel off Southern California. Data from these two sites span two orders of magnitude in b bp and likely cover typical open ocean values. A significant relationship is found between b bp at wavelengths of 442 and 555 nm and chlorophyll concentration. However the large spread in this relationship makes chlorophyll a poor predictor of b bp . The relationship between b bp and the particulate beam attenuation coefficient at 660 nm is tighter for both sites, indicating covariability of the particle size ranges that determine both coefficients. A detailed study of the seasonal changes of the b bp vs. chlorophyll relationship reveals that this bio-optical relationship might be best described as a succession of distinct regimes with rapid transitions from one to another. The backscattering ratio (b bp ; the ratio of b bp to total particulate scattering, b p ) ranges from about 0.2% to 1.5%, which is similar to previously reported values. The relationship between b bp and chlorophyll was not significant, while values of the backscattering ratio varied spectrally.

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Hurricane Felix passed over the Bermuda testbed mooring on 15 August 1995, providing a unique opportunity to observe the response of the upper ocean to a hurricane. In the vicinity of Bermuda, Felix was a particularly large hurricane with hurricane-force winds over a diameter of about 300-400 km and tropical storm-force winds over a diameter of about 650-800 km. Felix moved northwestward at about 25 km h Ϫ1 with the eye passing about 65 km southwest of the mooring on 15 August. Peak winds reached about 135 km h Ϫ1 at the mooring. Complementary satellite sea surface temperature maps show that a swath of cooler water (by about 3.5Њ-4.0ЊC) was left in the wake of Felix with the mooring in the center of the wake. Prior to the passage of Felix, the mooring site was undergoing strong heating and stratification. However, this trend was dramatically interrupted by the passage of the hurricane. As Felix passed the mooring, large inertial currents (speeds of 100 cm s Ϫ1 at 25 m) were generated within the upper layer. The e-folding decay timescale of the inertial currents was about 9 days. The mixed layer depth was about 15 m before the arrival of Felix and deepened to about 45 m within three days after Felix's passage; the temperature at 25 m decreased by approximately 3.5Њ-4.0ЊC. Large-amplitude temperature oscillations (ϳ1.5ЊC) near the inertial period (inertial pumping effect) were set up by the hurricane in the seasonal thermocline resulting in vertical displacements of isotherms of approximately 15 m at 60-70 m. Comparative scale analyses of the upper-ocean responses to Hurricane Felix and Hurricane Gloria (1985) indicate that they have several similarities.

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