X-Lander Altimeter Funkiness

I set my reference altitude at my current location to 610 feet above sea level. Why does the alitmeter keep changing altitude over time? I have not moved the watch from it's current location in my flat, yet the altitude now says 740 feet!

Help!
/Daniel

[AltimeterGuy]

This is true with all altimeters. The altimeter works off of barometric pressure. The fact that your altimeter increased 130 feet means that your sea level barometer inches of barometric pressure at one time has dropped a little over .10 inches of Mercury. A drop of .05 inches of Mercury increases your altimeter 50 feet and vice versa. A drop in barometric pressure means that a weather front had moved in. The first barometric pressure display on your Xlander screen is the "absolute barometric pressure" factoring in weather and elevation where you are at. By pressing the "select" button three times in the barometric pressure mode will take you to the sea level adjusted barometric pressure. This is where it will show the change in weather at your base elevation. Sea level adjusted barometric pressure is the barometric pressure you see on the news, Weather Channel and http://www.weather.com/ If you adjust your sea level adjusted barometric pressure, it will in turn adjust your altimeter. If you adjust your altimeter it will also in turn adjust your sea level adjusted barometric pressure. I hope this helps your understanding of altimeters and barometers. Altimeters are an "estimate" based on barometric pressure an not an absolute like a second ticking on a Celsium Atomic clock.

AltimeterGuy

	Suunto X-Lander - Click for more info The Suunto X-Lander watch is the combination of an altimeter, barometer, compass and watch - the same features as the award-winning Suunto Vector, but with a mineral crystal glass face, carbon fiber back, and a leather or polyurethane band.