The top symbol I am not sure of
I think it is the Angle of Attack ,if it is, it is used to moniter AoA during approach to landing
The "M" I believe is the mach number "Mach number is your present TRUE airspeed expressed as a multiple of the speed of sound at your present altitude. The speed of sound reduces from 661 knots at sea level to 573 knots at 36000 ft
The "G" Indicates the current G-Load affecting the aircraft, a negative (-) will appear infront of the number when pulling negative G's
Hope this helps
Randy
