Wednesday, June 13, 2012

A Neat Result on Sea Level Rise

Here is a nice result: a sudden polar meltwater input of 100,000 m3/sec -- say, from a broken ice dam, or just a huge amount of sustained, extreme melting -- would, in about a week, cause sea level to rise everywhere across the globe, at an average rate of 9 mm/yr.

Here is the computed spread of water across the globe after 5 days (left) and 6 days (right):

and a temporal view:

The authors say this amount of melting is the equivalent of 3,150 Gt/yr of ice melt; recent ice loss from Greenland is about 179 Gt/yr.

The Missoula Floods that created the Washington (state) Scablands were estimated to be 9 cubic miles an hour, which is 10 million m3/sec, or 100 times the rate in this paper.

By way of comparison, the average discharge from the Mississippi River is 17,000 m3/sec;
from the Amazon River, 209,000 m3/sec;
from all rivers worldwide about 1 million m3/sec (= 1 Sverdrup).

It takes about 55 days seconds for 100,000 m3 of water to fall over Niagara Falls (both falls).

The volume of one of the World Trade Center towers was 1.7 million m3;
the volume of the interior of the New Orleans Superdome is 3.5 million m3.

(Lorbacher et al, JGR-Oceans, 2012)


Vinny Burgoo said...

100,000 m3/s gives an annual flow about six times the volume of Wales.

John Cross said...

Hi David: you should check your 100,000 m3 over Niagara falls number. Back of the envelope guess says that it is off by an order of mag.

Delete this post if you wish.


David Appell said...

Thanks John, you're right. It's about 55 seconds, not 55 days.