What is the effect of ELR at 1 degree per 100 meters?

The choice indicating a neutral effect when dry reflects the understanding of the Environmental Lapse Rate (ELR) in the context of aviation meteorology. When the ELR is 1 degree per 100 meters, this signifies a scenario where the temperature decreases with an increase in altitude at a standard or typical rate. In dry atmospheric conditions, this consistent decrease does not cause significant instability or turbulence, making it a neutral condition rather than positive or negative.

In contrast, a positive or negative effect often relates to more extreme lapse rates. For instance, a steeper lapse rate typically indicates potential instability and rising air, which could lead to turbulence or various weather phenomena. In dry conditions, however, a standard lapse rate like the one mentioned generally maintains a stable atmosphere, hence the designation as neutral.