S-NPP/VIIRS Ocean Color Data and Global Modeling: Extending the Time Series of Ocean Biology from Space

Abstract:

S-NPP/VIIRS is the third leg of the modern record of ocean biology observations from space. Following now-defunct SeaWiFS and aging MODIS-Aqua, VIIRS can potentially extend our time series, which is critical for our understanding of ocean biological processes and how they are changing. Using in situ data to correct biases in satellite observations and data assimilation to remove sampling bias, we are able to construct consistent time series of ocean color data from 1998 to 2012. From this record, we found that global chlorophyll concentrations exhibited no change, but regional declines, concentrated in the northern hemisphere oceans, were apparent. Further, these declines were due to decreasing trends in diatoms, as a function of decreasing mixed layer depth. Applying similar methodologies to VIIRS, we hope to utilize this new sensor’s capability to understand if the trends previously observed are changing.