Hello Frank and Mike,
I wonder if another means of calculating oceanic residence time would
be to use the total volume flow of the the world's rivers per annum as
compared to the total volume of the world's oceans? Of course not all
precipitation occurs over land but this could be accounted for based on
area and precipitation distribution. I can check on the river flow value
and see if indeed it matches your 4000yr value. To keep the thread
"on-topic" how many years would it take for the same water molecule to
fall on a given sundial, perhaps the LongNow group would be interested!
Finally, I have "heard" that a given water molecule flowing down the
Rhine will on average flow through four humans before exiting (with
great relief) into the ocean.
Best,
Luke
Frank Evans wrote:
>
> This is all definitely off topic. But with apologies here goes.
>
> ><So how many times have we 're-cycled?' the drinking water>
> >
> >Wasn't there once a Scotsman who poured a bottle of Scotch over his friends
> >grave every year on the anniversary of his death? He just filtered it
> >through his kidneys first to avoid the waste.
> >
> >Mike
> >
> The world's great oceans, Pacific, Atlantic and Indian, are on average
> 4000m deep. Annual evaporation averages around 1m. Sea level is fairly
> unchanging. The oceans are well mixed or they would stagnate. So the
> residence time of a water molecule in the sea is on average 4000 years.
> In other words oceans renew themselves in only 4 millennia. Seems
> improbable? Ripley (Believe It Or Not) would be proud.
>
> Frank 55N 1W
> --
> Frank Evans
