15 July 2010

Geek day - the Earth's water

I remember when I was at school and I saw an image of the World with no oceans. I was blown away by it. You could see the mid-ocean ridges, cut by transform faults, the shelf, the slope, the oceanic trenches - it brought plate tectonics to life.

Now such images are common, you can even see the bathymetry on GoogleEarth, which is awesome, but we have become used to seeing it and the impact is less, although I can still spend hours wandering the global

Then I found the image below and it showed the volume of all the Earth's water relative to the volume of the planet - and its tiny! Makes you think about the size of the Earth and how thin a layer, even the deepest oceans actually make.


Liam Herringshaw said...

Do you know if there is an image of the world without water where the continents and countries are no longer marked with their normal, sea-level coastlines? I'd be really interested to see an image where different heights above absolute base level are shown in different colours, to strip away political and current eustatic boundaries.

John said...

Liam, I know what you mean and I have not find a picture specifically like that. I could probably generate one in Arc GIS but I have two jobs and a blog already... maybe when I have a spare moment, and also to raise and lower sea-level on hmmm - now there is a plan for a web app.

In the meantime the best I have found is here http://www.ngdc.noaa.gov/mgg/image/color_etopo1_ice_low.jpg which shows topography above and below current msl although everything above is shaded green-brown and everything below is blue, at least there is no political boundaries and the relief is there