Elementum

Elementum Terra

Why is the barometric pressure trend arrow flat even though the weather has changed?
The Elementum Terra includes an air pressure sensor which measures the absolute air pressure surrounding the watch. Based on this measurement and your current altitude that you have set on the watch, the Terra calculates the corresponding sea level air pressure, which is shown on the outer rim of the display. Significant changes in sea level pressure – often indicating a weather change – are shown by the barometric pressure trend indicator (the arrow in the top of the display).

Unfortunately, it is not possible to measure weather changes and altitude changes at the same time as both cause a change in the absolute air pressure. The Elementum Terra senses vertical movement or lack thereof, and switches between measuring altitude or weather changes accordingly.

If you are at a constant altitude (watch assumes this when it has observed less than 5 m of vertical movement in 12 minutes), the watch measures weather changes. The altitude reading will stay steady, and if the weather changes you will see changes in sea level air pressure and the pressure trend arrow (if change is significant enough*).

If you are on the move (watch assumes this when it has observed more than 5 m of vertical movement within 3 minutes), the watch measures altitude changes. The sea level pressure will stay steady and the altitude reading will change according to your vertical movement. Any pressure change actually caused by a weather change will now be interpreted as a change in altitude and not in weather, thus the barometric trend arrow will remain horizontal.

* The baro trend arrow shows the barometric trend of the last 6 hours. The left side of the arrow represents 6h -> 3h history and the right side of the arrow represents last 3 hours of pressure history. The baro trend arrows are updated every 30 minutes. Only significant changes (2 hPa or more in 3 hours) are visible in the trend arrow.