Air masses lapse rate

[vector767]

Hello!
Can anybody answer these questions?
If the air masses lapse rate is2 deg. per 1000',and the air is saturated, is the atmosphere stable or unstable?

Besides using the scale, where can you measure distance on
a Jep Chart?

[FlapsOne]

If a particle of air is displaced under these conditions it will cool at the Wet ALR of circa 1.5 C /1000' thus it will remain WARMER than the surrounding air. Thus the tendancy will be for it to continue rising. ergo UNSTABLE

Try using a known and marked distance from the JEPP charts as a guideline- between two reporting points for example.

[invalid entries]

Vector767 is correct about the unstable air.
The scale can also be measured on a chart using the latitude markings, knowing that each minute of latitude is one nautical mile.

[bookworm]

If the air masses lapse rate is 2 deg. per 1000',and the air is saturated, is the atmosphere stable or unstable?

Strictly speaking, it depends on the pressure and tempearture you start from.

While the dry adiabatic lapse rate (DALR) is pretty much a constant, the saturated adiabatic lapse rate (SALR) depends on how much water you condense out of the air. At higher pressures and temperatures there's more water and hence more latent heat coming out as the parcel goes up -- so the SALR is less. In a cold airmass starting at a few thousand feet, you might just find that the SALR is greater than 2 degC per 1000 ft, and hence the air is just about stable.