Global seasonality

April 17, 2012 – 3:50 pm


I tweeted:

I’m referring to the animated gif above. Click for the full size version.

I then had the following email exchange with my mom:

Mom: Anthony, what is going on in that graphic? Is it a joke?

Me: lol no joke, it’s actual satellite images of seasonal change in earth surface color throughout the year. Mainly you can see snow extent and when different parts of the world are in their growing seasons.

Mom: Ah ok — so what ten things did you learn? Clearly you need specialized knowledge to interpret that animation.

Challenge accepted! Here are 10 things I did not know before staring at this graphic for a while:

1. While there is permanent snow/ice cover in Antarctica, there is almost no seasonal snow cover in the southern hemisphere.

2. Permanent snow/ice cover near the north pole includes not just Greenland, but also many other large islands in northern Canada like the Sverdrup islands.

3. During the winter, the boreal forest is not as white as the tundra above or the plains below (lower albedo), presumably due to the trees poking out from the snow.

4. In Australia, plants on the northern coast green up in the summer while plants on the southern coast green up in the winter.

5. A huge swath of Brazil has deciduous vegetation (also, Madagascar).

7. The rainforests of South America, Africa, and Southeast Asia that stay green all year round are a lot greener than even peak greenness in the nearby seasonal ecosystems.

8. The permanent snow in the Himalayas is mostly constrained to a thin band where the subcontinent is smashing into Asia.

9. The Amazon river becomes so massive during the rainy season you can see it from space (at least I assume that is what’s going on there).

10. The Nile River delta dries up twice a year. Notice how it flickers more than once per annual cycle in the gif. Here’s an animation¬†that confirms this.

Also, this is more geography, but I had never noticed the Kerguelen Islands before. Looks like it is pretty snowy there in the winter.

And a final observation from an imgur commenter in Britain:

  1. 4 Responses to “Global seasonality”

  2. I’ve been doing some volunteering for the Denver Museum of Nature and Science, and I prepared some training materials for a spherical projection of these data which we project onto a sphere. It’s completely awesome, and a great teaching tool – a lot of the observations you make here are in my training docs.

    The one that always bakes people’s noodles is the fact that Brazil is not just Amazon. There’s a whole lot of savanna, shrubland, and veldt-like vegetation, especially in the south and northeast. It IS at the same latitude as South Africa, after all…

    By Charlie Lawton on May 10, 2012

  3. Cool Char, I saw one of the globe projection systems at the Tech Museum in San Jose, but not with these sorts of satellite data. Sounds sweet. Good job teaching global ecology to the masses!

    By Anthony on May 11, 2012

  4. Hi Anthony, nice job. I love what MODIS did for phenology.

    however, 3 & 10 be owing to
    3. shadow owing to extreme look angles on MODIS in the high latitudes? but like the idea of low albedo due to conifers
    5. the Cerrado drying out?
    10.the cropping cycle?

    Ranjeet, who lives down the hall

    By ranjeet on Oct 3, 2012

  5. Thanks Ranjeet! Great ideas. You’re probably correct on all accounts. Do you mean shadow from the trees. If so, wouldn’t that have the same effect on energy balance? I guess maybe it’s less dramatic on the ground than from that angle though?

    By Anthony on Oct 4, 2012

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