HiRes NOAA OI SST with WebGL and Movie


Collection of High Resolution NOAA SST with WebGL

Shown here is one day AVHRR satellite SST anomaly data kindly provided by NOAA. It has 1/4 degree (about 25km) resolution. They have a suggested form of acknowledgement, which is: NOAA High Resolution SST data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/.


The plot uses WebGL to provide interactivity. The globe is a trackball - you can drag to rotate, and use the right button with vertical motion to zoom. The method is described in this post.

You can choose resolution of 1, 1/2 or 1/4°. Coarser is faster. At 1/4° (about 25 km) the picture can take a few seconds to appear, and you may hit memory limits. This page challenges browser and video card capabilities; Firefox and Chrome work for me, but not IE. Safari doesn't have WebGL on windows, but I believe it does on a Mac if .


Data goes back currently to 1996, daily back to early 2010, then weekly, then monthly. You can choose a date from the selection boxes on right. Choose the year first, then month and day. With each choice lower boxes will change to reflect what is available. When selected, click the Plot button.
Update - I've added a movie facility, described here. I'll add that description below the plot.
 








Movies


I have added a movie facility show you can see the dynamics of processes like ENSO. The process works like this. First you select your start date and resolution, as if you were plotting that date. But instead of New Plot, go to the bottom, next to the new Seq button and enter the Step (interval in days) and Number (of frames in the movie).

Then press Seq. This will download the data for the frames. At 1° resolution, this will show as a passable movie, but at 1/4° it will be painfully slow. But let it run. You'll see a pink window just above counting the frames - it will revert to pale green when finished.

Now the payoff - next to the Cyc button you can enter the cycle time for the real movie. For resolution 1/4° you may find that times less than 1 sec will lead to skipping frames; coarser resolutions should do several frames per second (if you really want). Then press Cyc to run the same sequence that you just downloaded, but at the faster speed.

Long sequences at high res will be a load on memory - I estimate about 3-4 Mb per frame. I've been juggling memory vs speed - I can run very fast, but needing 10 Mb per frame.

You can rotate or zoom while the movie is running. You can rerun (Cyc) as you wish. You can go on to do other plots or make more movies, but then you can't rerun the one you had been watching.

I've found that it works as described in Firefox. In Chrome it works, but doesn't show the frames while loading (following Seq) and the red colors don't show to indicate. The movie is OK though.
Update - if you change resolution, you need to re-select the date (even if you think the one showing is OK).


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