While conducting a mortar registration and spotting one airburst and three graze bursts, what should your correction be?

When conducting a mortar registration, it's essential to analyze the types of bursts observed to determine the necessary corrections. In this case, having one airburst and three graze bursts indicates that rounds are impacting high and closer to the target.

An airburst occurs when a round detonates above the ground, and a graze burst is when the round impacts the ground just above or at the surface. With one airburst and three graze bursts, the mortar fire is likely impacting well above the intended target due to the airburst and just below it with the graze bursts.

To adjust for this pattern, an upward correction is necessary because the airburst suggests that the initial rounds are falling too low in elevation, and an upward adjustment would bring the fire closer to the desired point of impact. Hence, a correction of "Up 20" would be appropriate to adjust the firing solution upwards, allowing for a more precise strike on the target based on the observed distances of the bursts.