MODIS Derived Chlorophyll a dataset: Seasonal Variations
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<p>The dataset measures the long-term seasonal variations of the chlorophyll a concentrations of ocean surface waters. They are derived from MODIS (aqua) images using NASA's SeaDAS image processing software. The monthly chlorophyll a images between July 2002 and December 2017 are used to calculate the standard deviations of the four austral seasons: winter (June, July, and August), spring (September, October and November), summer (December, January and February) and autumn (March, April and May). The extent of the dataset covers the entire Australian EEZ and surrounding waters (including the southern ocean). The unit of the dataset is mg/m3.
<p>This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.
Australian and New Zealand Standard Research Classification: Fields of Research
National Environmental Science Program
Marine Biodiversity Hub
Australian Government Security ClassificationSystem
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The daily MODIS Aqua Chlorophyll a images processed to Level 2 were obtained from the Integrated Marine Observing System (IMOS; http://imos.org.au/) remote sensing facility. The Chlorophyll a algorithm used is the semi-analytical GSM algorithm (Garver and Siegel 1997; Maritorena et al. 2002). The monthly Chlorophyll a images were generated by mosaicking the daily Chlorophyll a images, where the overlapping locations have average values of the overlapping cells. The seasonal standard deviations were then calculated from the monthly images of the corresponding seasons between July 2002 and December 2017. For example, the winter standard deviation was obtained from all June, July and August images. The spring standard deviation was obtained from all September, October and November images. The summer standard deviation was obtained from all December, January and February images. The autumn standard deviation was obtained from all March, April and May images.
The Great Barrier Reef and a number of offshore reefs have been masked out due to the unreliable MODIS Chlorophyll a values known to occur at these shallow water areas.