Nink wrote:Before I answer the question in regards to the makeup of the ~3*10^15 kg per year, and how something of such mass could enter our atmosphere relatively undetected, I would like to ask a couple of questions please.
1) Where did the ~1,386,000,000 cu km that scientists currently estimate or 1.386*10^21 kg of water on earth originate from?
What do you mean with "originate from" and when? Afaik the current models are debating endogenic (produced by the Earth itself) or exogenic (water meteorites) origins or the combination of those two.
I see many more arguments for the endogenic origin maybe aided by some wet meteorites:
- H2O is a simple molecule
- electrolysis and the opposite binding of H2 and O2 does not seem a complex process
- the Earth itself is very rich in different elements and H and O are very abundant
- for decent volumes of water to produce an endogenic origin makes sense
- we see it happening on Earth; hydrous minerals are exhumed in volcanic eruptions
- the cycle of water and oxygen is pretty well understood for the recent past (dO18/O16)
2) If the earth has remained the same size but the oceans according
to previously posted data, managed to rise and fall ~250 m over the past 200 million years, and if we assume this information is correct, where did that volume of water come from, and where did it go?
Sea level consists of 2 types:
- relative sea level - the sea level w.r.t. a local datum
- global, eustatic, sea level - the volume of water in liquid form in seas and oceans
You are and must be referring to the latter. For the recent ice age periods the sea level is mainly controlled by how much of it is stored in solids (ice) in glaciers and polar ice caps. Today that is volume X (and don't fall for the Antropogenic Global Warming Hoax that claims we will go to an ice-free world...).
In a complete greenhouse that X is increased by the volume of water now stored in ice (minus lakes and rivers that will be formed) and in a complete icehouse that X is decreased by the extra ice formed). The greenhouse/icehouse periods are in turn controlled by astronomical (Milankovitch) parameters; the position of the Earth w.r.t. the Sun. Which is also an interesting gravitational question in itself.
This glacial vs. interglacial variation alone can change the global sea level by some hundred meters and can be calculated (X0 +/- the ice volume).
For longer geological periods the global sea level is thought to be controlled mostly by the average rate of sea floor spreading (how fast new crust is created) and related subduction (how fast that crust is "consumed" again by the asthenosphere at subduction zones (e.g. the Pacific Ring of Fire). That is explained in more detail in the link I provided with the Eustatic Sea Level Curves on the previous page.
On your question; the vast majority of all water on Earth is not moving on top of the crust (seas, rivers and lakes; liquids, glaciers; solids and clouds; vapours), but is "stored" in hydrous minerals in the crust (clays and micas, zeolites and others) and mantle (same minus clay minerals).
This water is released more or is released less with varying spreading rates which results in changing H2O amounts on the surface.
At least this is the current model and so far I have not seen convincing arguments to doubt that, but I am open and all ears to get convinced of other views.