Underneath the equator


Guest contribution by Willis Eschenbach

Inspired by my previous posts, Boy Child Girl Child and Sea Levels in the Nino-Nina Cycle, I decided to take a look at what is happening under the ocean's surface along the equator. One commenter referred me to an Australian archive of past underground research with an unfortunate url that contains "oceantemp / pastanal /" … but I digress.

These analyzes show longitude on the horizontal axis and depth on the vertical axis. Here is her view of the El Nino summit in November 1997. The black area on the right is South America and the black area on the left is Africa. The flat zone between 90 ° E and 120 ° E is Indonesia and Borneo.

Figure 1. Vertical section temperature analysis of the equatorial Pacific Ocean for Peak El Nino, November 1997. The date is shown in the center. The upper field shows the "climatology", an artificial term that means the long-term average of the climate variables for the month. In this case the variable is the temperature distribution. The middle field shows the actual temperatures for the month. And the last field shows the “anomaly,” which is the actual temperature minus the climatology. That is how hot or cooler the ocean is this month in this place.

In Figure 1, you can see how the anomalous heat in the Eastern Pacific off South America extends from surface to depth, a few hundred meters. The grade “H” shows that the maximum value is over eight degrees above average. There is also a corresponding underground cooling point to the west of it, which according to the L-Note is about six degrees cooler than average. Big swings.

Compare that with the situation a year later, in November 1998 at the height of the corresponding La Nina.

Figure 2. Vertical section temperature analysis of the equatorial Pacific Ocean for Peak La Nina, November 1998.

Here we can see that the warm water has been pulled out and replaced with the colder underground water that has now come to the surface.

And to get a better understanding of the underwater world, I made a film here about the monthly situation from 1995 to 2008 when they changed the format. See the end note for details on how I made the film.

Figure 3. Monthly changes in temperature analysis in vertical section.

Always to learn more … please quote what you comment to avoid misunderstanding.

Half moon tonight, fresh and cold. The deer came by again today. Hummingbirds drank from the flowers. Life in the forest doesn't care about politics, which strikes me as a brilliant plan these days. The silence of the forest is my balm and my refuge.

My best regards to all,


Final grade: To make the movie, I had to first download the .GIF files. I do most of my work in the R computer program. If you're programming, R should be your study. Free, cross-platform, free killer user interface called RStudio, interpreted. But I digress. I first had to create the year / month number combinations that the Aussies used in the URLs of the graphics. Here is this code. Anything on a line after a hash "#" is a comment.

allyears = paste0 (rep (1995: 2020, each = 12), two-digit (rep (1: 12.26)) # repeats the numbers from 1995 to 2020 twelve times and inserts the two-digit representations of the months each
head (allyears) # shows the first data points of the variable
(1) 199501 199502 199503 199504 199505 199505 199506

("Two-digit" is a function I wrote because I couldn't remember the actual code to format a two-digit number.)

two digits = function (x) {
if (is.numeric (x)) {
sprintf ("% 02d", x) # formats numbers
} else {
format (x, digits = 2) # formats text

Then I created a folder (directory) to store the .GIF images and put the path to the folder in a variable.

dir.create ("Aussie Underwater All")
Path name = "Aussie Underwater All /"

Then I wrote a loop to read each .GIF and write it to the folder. Comments after the "#" on each line.

for (i in 1: length (allyears)) {# cycle through all years

print (paste0 (allyears (i))) # prints the progress

aurl = paste0 ("http://www.bom.gov.au/archive/oceanography/ocean_anals/IDYOC002/IDYOC002.", allyears (i), ".gif") # Paste the URL together

mygif = image_read (aurl) # Reads the GIF image file at this URL

image_write (mygif, paste0 (pathname, base name (aurl))) # Write the image file in the folder created above.

Once I had the pictures, I did the rest online. Upload the images to the animated GIF maker and create an animated GIF. Upload the animated GIF to CloudConvert and convert it to MP4. The whole thing took me a couple of hours.


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