Tuesday, December 17, 2013

Mahmud Hasan Ghani's Internship, Fall 2013 - Part 7

SST Satellite Products 

I mentioned in my last blog that I have found a good correlation in the Aqua MODIS global sea surface temperature (SST) products with our SailBuoy data. Today, I intend to discuss more details about the satellite-derived SST products and how the product is more validated with the reference data.

From several SST products of different resolution of Aqua MODIS, I am using one of the standard products for my comparison. This Aqua MODIS Level 3 global product is a daily global 4 km SST product available on the OceanColor website on a daily basis. Here question may arise, that one full analysis is remained for Terra MODIS which has the same quality SST products. At the beginning stage, I studied both Aqua and Terra MODIS products for the same in situ data. After several comparisons between Aqua MODIS and Terra MODIS, I had decided to go for the Aqua MODIS, as it seemed better relevancy in retrieved data. But that does not neglect the Terra MODIS, when in this term I am focusing one product only. There might be another complete series of analysis which can be interesting to find out the best validated product. Usually, it will take more time to download the images and to process the data to fit with the SailBuoy data. So, there is a scope to more analysis in between the satellite products.
Figure 1: Day-wise SailBuoy SST vs satellite-derived SST.
However, coming to the current analysis, the figure is showing the day-wise surface temperature variation in the Northern Gulf of Mexico from where the SailBuoy started to transmit data on March 15, 2013, and ended on May 15, 2013. I have mentioned that this satellite product is from level 3 products, but there is another option for a day-wise level 2 product on the OceanColor website. It is important to mention this level 2 product, as there is some limitation in the coverage area of the satellite image, which could miss some study area in a particular day. The images are not in similar style for all days to cover the whole Gulf of Mexico; so level 3 global products are better than level 2 to find out the location wise SST values mentioning the latitude and longitude through the daily images. It reduces the chance of missing the right locations and retrieval of SST values.
Figure 2: Scatter plot of satellite-derived SST vs SailBuoy SST (62 days).

Posted By:
Mahmud Hasan Ghani, Norwegian Meteorological Institute

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