# Trying to resolve a volume calculation

• narrator

#### narrator

Hi all, I've made errors in my calculations and need help.

I'm trying to calculate the volume of a layer above sea level to the height of Flight Level 300 i.e. 30,000 feet. Next, I want to subtract the volume of land within that layer. Here are my calculations.
Purely for the sake of my calculations, I'll treat the earth as a perfect sphere, and I'll round 30,000feet to 10,000m.

1. The radius of the sphere of earth at sea level is approx 6,378,000m. That would make its volume approximately 1.08675x10^21 cu.m.

2. From the height of FL300 (30,000ft) or (rounded) 10,000m the radius increases to about 6,388,000m. The total volume of the larger sphere would be 1.09187x10^21cu.m

3. Subtracting one from the other leaves the volume of the layer at about 5.12x10^18cu.m.

4. There is no landmass above FL30. I've googled the total volume of all land masses within that layer (i.e. above sea level) and the only answer I can find (in 3 places) is 1 trillion cu.km or around 1x10^21cu.m. If this is true, then my calculations are badly wrong.

I would love your help with this? And thank you in advance.

Last edited by a moderator:
narrator said:
I've googled the total volume of all land masses within that layer (i.e. above sea level) and the only answer I can find (in 3 places) is 1 trillion cu.km or around 1x10^21cu.m.
I find a different estimate, 125,109,600 km3, here.

• narrator and scottdave
Hill said:
I find a different estimate, 125,109,600 km3, here.
Thanks for that. I found the Wiki article that your link refers to. Excellent! Much appreciated!

• scottdave