New SST product
As well as the re-design the new Four-hour SST product is now available on IMOS OceanCurrent. It uses Himawari-8 SST images (and all other available SST) to provide 6 images per day.
Four-hour SST, as its name implies, provides an image every 4 hours using all 10-minute data within a 4-hr time-window. There is also a parallel product called Filled-SST where the cloud gaps are filled with the latest previous SST. We have included the average wind speed (courtesy of the Bureau of Meteorology) as well, in order to help identify low-wind regions where the SST only represents a thin, extra-warm layer at the surface. The image at right demonstrates such a phenomenon, often called the afternoon effect because it is usually maximum in the late afternoon. Note the time of the image at 0800 UTC is 4pm AWST. We have timed the Four-hour SST to catch peak afternoon effect (0600 UTC on the east coast) because it can impact near-surface corals. Although the heating is unlikely to cause any problems in winter, it is interesting to see the cooler outline of Scott Reef (at approx. 122E and 14S) most likely due to the effect of tides.
The website redesign means that choosing between our growing list of SST and Chlorophyll-a products is easier. With the new navigator it is easy to flip between different types of SST to compare and pick the best one for the job. The Four-hour SST is expected to be more reliable and with less cloud than the Snapshot SST but because of the averaging the fronts will not be as sharp. The 6-day SST is even more smoothed, being an average of all night-time data in a 6-day window. We use the 6-day SST to calculate a conservative estimate of the SST percentiles by referencing the image to the statistics of SSTAARS. These statistics are for 1-day night-only averages, so our percentiles are slightly skewed towards the median.
Animations of each product are easily accessible through the ‘film’ icon on the navigation bar. The ‘Permlink’ button provides an way to send someone the link to an image. Of course, not all SST products are available for all times. For example, at this stage, Four-hour SST is only available from 10 August 2017. Himawari-8 was launched in 2015 so eventually we will be able to backfill to 2015. We have also included images of SSTAARS climatology (one per month) for each region.