This resource is daily means of Chla measured by the Aqua satelite which represents phytoplanton in the water for the periods 2018-2023 and 2022-2023. The Aqua satellite platform carries a MODIS sensor that observes sunlight reflected from within the ocean surface layer at multiple wavelengths. These multi-spectral measurements are used to infer the concentration of chlorophyll-a (Chl-a), most typically due to phytoplankton, present in the water. There are multiple retrieval algorithms for estimating Chl-a. These data use the OCI method (Hu et al 2012, doi: 10.1029/2011jc007395) recommended by the NASA Ocean Biology Processing Group and implemented in the SeaDAS processing software l2gen. The OCI algorithm is described at https://oceancolor.gsfc.nasa.gov/atbd/chlor_a/ (and links therein).

This resource is Sea Surface Temperature derived from the MODIS Satelite for the tie period 2018 - 2022 and current 2022 - 2023. The MODIS Sea Surface Temperature product is derived from MODIS bands 31 and 32 according to the algorithm described at https://oceancolor.gsfc.nasa.gov/atbd/sst/. This is not a GHRSST-quality product, and demanding applications requiring a high standard of accuracy should consider using one of the IMOS GHRSST products in preference. The MODIS SST is nevertheless useful primarily because it is measured at the same time as the water leaving radiances used to derive the optical properties (eg chl). This means it is both contemporaneous, and has a matching cloud mask, so it is valuable for applications that seek to combine both SST and optical properties (ie Net Primary Productivity variants). The data set provided here matches the Chl_oci product in temporal and spatial extent. This SRS dataset covers waters around Australia.