MODIS derived Total Suspended Materials (TSM) datasets
The TSM datasets are derived products of MODIS (Aqua) images. SeaDAS (version 6.1) was used to process the MODIS data from raw to L3 products. The algorithm used here is the Clark algorithm (Clark et al., 1980): a0=0.490330 a1=-2.712882 a2=3.412666 a3=-8.336478 a4=12.111023 a5=-5.961926 nLw1: Normal...
| Summary: | The TSM datasets are derived products of MODIS (Aqua) images. SeaDAS (version 6.1) was used to process the MODIS data from raw to L3 products. The algorithm used here is the Clark algorithm (Clark et al., 1980): a0=0.490330 a1=-2.712882 a2=3.412666 a3=-8.336478 a4=12.111023 a5=-5.961926 nLw1: Normalised water-leaving radiance at 443 nm nLw2: Normalised water-leaving radiance at 488 nm nLw4: Normalised water-leaving radiance at 551 nm X=log10((nLw1 + nLw2) / nLw4) TSM=power(10, (a0 + X * (a1 + X * (a2 + X * (a3 + X * (a4 + X * a5)))))) The nLw1 and nLw2 can be derived directly using SeaDAS. In addition, Normalised water-leaving radiance at 547 nm and 555 nm were derived to calculate nLw4 (simple averaging). The sequences of processing included: 1. raw - L1A, 2. L1A - L1B, 3. L1B - L2, 4. L2 - L3 (spatial) binning, and 5. L3 binning to L3 time-binning. The first four steps were applied to all individual (daily) raw images to obtain the four Normalised water-leaving radiance products. After completing the above steps for one-month-worth images (around 300 images), in the fifth step, four weekly images were generated: 1. week1: from the 1st to the 7th of the month; 2. week2: from the 8th to the 14th of the month; 3. week3: from the 15th to the 21st of the month; 4. week4: from the 22nd to the last day of the month. The four weekly images were exported as HDF files, then imported into ArcGIS and converted into ArcInfo grids. Next, the weekly images of the four products were entered into the Clark algorithm described above to calculate weekly TSM products. Finally, the four TSM weekly grids were mosaiced into a monthly image using the averaging method. The above processes were repeated to generate the final 36 monthly datasets between 2009 and 2011. Clark, D.K., Baker, E.T., Strong, A.E., 1980. Upwelled spectral radiance distribution in relation to particulate matter in sea water, Boundary-Layer Meteorology, 18, 287-298. The datasets measure the Total Suspended Materials (TSM) concentrations of ocean surface waters. They are derived products from MODIS (aqua) images using NASA's SeaDAS image processing software. The extent of the datasets covers the entire Australian EEZ and surrounding waters (including the southern ocean). The spatial resolution of the datasets is 0.01 dd. The datasets contain 36 monthly TSM layers between 2009 and 2011. The unit of the datasets is g/m3. |
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