Phenological changes of oceanic phytoplankton in the 1980s and 2000s as revealed by remotely sensed ocean‐color observations

摘要: We investigated the phenology of oceanic phytoplankton at large scales over two 5-year time periods: 1979-1983 and 1998-2002. Two ocean-color satellite data archives (Coastal Zone Color Scanner (CZCS) Sea-viewing Wide Field-of-view Sensor (SeaWiFS)) were used to investigate changes in seasonal patterns concentration- normalized chlorophyll. The geographic coverage was constrained by CZCS distribution. It best for Northern Hemisphere also encompassed areas Indian, South Pacific, Equatorial Atlantic regions. For each 2° pixel, monthly climatologies developed satellite-derived chlorophyll, resulting cycles statistically grouped using cluster analysis. Five distinct groups mean identified half-decade period. Four types common both periods correspond previously regimes: Bloom, Tropical, Subtropical North, South. other cycles, one compared periods, related transitional or intermediate states (Transitional Tropical Transitional Bloom). (Bloom, South, Bloom) further confirmed when whole SeaWiFS set (1998-2010) analyzed. ~35% pixels analyzed, characteristic years differed little from those 1998-2002 ~65% pixels, however, seasonality changed markedly, especially Hemisphere. regions North Pacific experienced a widespread expansion Bloom regime, which appeared enhanced climatology based on full record (1998-2010), and, as showed more detailed analysis, is associated La Nina years. This spatial pattern regime reflects general smoothing macroscale, coming into an apparent greater temporal synchrony result higher variability, space time. observed change dynamics may be not only biological interactions but large-scale coupled atmosphere-ocean system. Some connections are indeed found with climate indices. Changes among belonging opposite phases ENSO, though discernible within era (1998-2010). These linkages considered preliminary present worthy investigation.