All Climate Events

Wednesday, October 9, 2019. 3:00PM. Webinar: Size-partitioned Phytoplankton Biomass in SeaWIFS (1997-2010): trends, variability and comparing satellite data with models. Irina Marinov, University of Pennsylvania. Sponsored by NOAA Ocean Color Coordinating Group. More information here. 

The focus of this talk will be on the use of satellite time series to characterize the structure and function of global marine phytoplankton ecosystems. The backscattering-based product of Kostadinov et al (2009,'16) yields particle size distribution and size-partitioned phytoplankton biomass. We use this product for multiple analyses of the SeaWiFS (1997-2007) mission as follows: 

(1) Unexpectedly, and unlike previous work, we find that globally and in the warm oceans the biomass and the percent of large (small) phytoplankton increase (decrease) over this period. In the subtropical gyres, chlorophyll a trends are likely due to physiological changes, while the increasing biomass trends are due to winds and relevant mixing length scale increases. The oligotrophic gyres contract or expand depending on the chlorophyll a threshold definition employed. 

(2) We use an agglomerative hierarchical clustering technique to show a clear separation of the East Pacific (EP) and Central Pacific (CP) ENSO events in our biomass product for the low latitude Pacific. We contrast the responses of phytoplankton biomass with those of chlorophyll‐a and their physical drivers in various types of ENSO.

(3) Finally, we discuss differences and similarities between our satellite-derived phytoplankton ecology metrics (e.g. seasonality metrics) and similar output across climate models (IPCC AR5 Earth System models). We find for example that climate models do not capture the pronounced mid-latitude and frontal PFT patterns found in the satellite data, and they exhibit more pronounced seasonal cycles and larger phenological differences between PFTs.