Satellite Sea Level Measurement
1993–2012 Sea level trends from satellite altimetry.Current rates of sea level rise from satellite altimetry have been estimated in the range of 2.9–3.4 ± 0.4–0.6 mm per year for 1993–2010. This exceeds those from tide gauges. It is unclear whether this represents an increase over the last decades; variability; true differences between satellites and tide gauges; or problems with satellite calibration. Knowing the current altitude of a satellite which can measure sea level to a precision of about 20 millimetres (e.g. the Topex/Poseidon system) is primarily complicated by orbital decay and the difference between the assumed orbit and the earth geoid . This problem is partially corrected by regular re-calibration of satellite altimeters from land stations whose height from MSL is known by surveying. Over water, the height is calibrated from tide gauge data which is needed to correct for tides and atmospheric effects on sea level.
Read more about this topic: Current Sea Level Rise
Famous quotes containing the words satellite, sea, level and/or measurement:
“Books are the best things, well used; abused, among the worst. What is the right use? What is the one end, which all means go to effect? They are for nothing but to inspire. I had better never see a book, than to be warped by its attraction clean out of my own orbit, and made a satellite instead of a system.”
—Ralph Waldo Emerson (1803–1882)
“the whole sea become an entanglement of watery bodies
lost to the world bearing what they cannot hold. Broken,
beaten, desolate, reaching from the dead to be taken up
they cry out, failing, failing! their cries rising
in waves still as the skillful yachts pass over.”
—William Carlos Williams (1883–1963)
“To punish drug takers is like a drunk striking the bleary face it sees in the mirror. Drugs will not be brought under control until society itself changes, enabling men to use them as primitive man did: welcoming the visions they provided not as fantasies, but as intimations of a different, and important, level of reality.”
—Brian Inglis (b. 1916)
“That’s the great danger of sectarian opinions, they always accept the formulas of past events as useful for the measurement of future events and they never are, if you have high standards of accuracy.”
—John Dos Passos (1896–1970)