next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects
Index of Subjects Interesting original question from Paul, so I looked it up in (where else but?) Wikipedia -> sea level -> mean sea level (MSL), where there's a readable but somewhat technical explanation. Conceptually, MSL is defined apparently by a 3-dimensional imaginary geometric surface hovering around the earth, a geoid, at which sea level would equilibrate if there were no variations in air pressure etc, but from which there are real departures of up to +/- 2 meters. It also says that an ellipsoid surface is easier to model than a geoid in order to tie into the GPS system for aircraft navigation, for aviators who wish to land on aircraft carriers, etc, and is increasingly used. Changes in MSL over geological time are also covered a bit. The article also mentions apparent changes in sea level caused by land sinking or rising locally, but you'd need to look elsewhere for specifics. I also thought that NS overall was still rebounding slowly from the oppressive weight of the last ice age, but it would need a geologist to tell us whether such changes are bigger or smaller than the projected rise in overall sea level caused by such things as current and future melting of ice on land, and sea water warming. Steve, Halifax On 7-Mar-07, at 1:34 PM, Gerald Ruderman wrote: > Heather Drope wrote: > . . . . >> I have heard that the province is sinking and the oceans are >> raising. If >> that is the case I wonder what they do then about their bench >> marks?Will >> they be adjusted or is this something we don't have to worry about in >> my >> generation. Heather > > Sinking! I thought it was still springing back up after being pushed > down during the ice age. I do agree about the oceans rising. >
next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects