# US Standard Atmosphere, 1976

As published by NOAA, NASA, and USAF

The standard atmosphere is mathematically defined in six layers from sea level to 71 km.

 Layer Name Lower Altitude (km) Upper Altitude (km) Upper Altitude (ft) 1 Troposphere 0 11 36,089 2 Stratosphere 11 20 65,618 3 - 20 32 104,987 4 - 32 47 154,199 5 - 47 51 167,323 6 Mesosphere 51 71 232,940

h = altitude above sea level in feet or meters.

T0 = Absolute temperature at sea level = 288.15 K = 518.67 R (or 15° C = 59° F)

r0 = Density of air at sea level     = 1.225 kg/m3 = 0.07648 lb/ft3 = 0.0023769 slug/ft3

P0 = Standard air pressure at sea level = 1 Atm = 101325 N/m2 = 2116.2 lb/ft2 = 14.696 lb/in2 = 29.921 in of Hg

 # Altitudes up to: English Units Temperature (R) Density         (slug/ft3) Pressure       (lb/ft2) Metric Units (K) (kg/m3) (N/m2) h is measured in: feet meters 1 11 km T = T0 (1 – h / 145442 ft)  r  = r0  (1 – h / 145442 ft)4.255876 P = P0 (1 – h / 145442 ft) 5.255876 T = T0 (1 – h / 44329 m) r =  r0 (1 – h / 44329 m) 4.255876 P = P0 (1 – h / 44329 m) 5.255876 2 20 km T = T0 (0.751865) r  = r0 (0.297076)e((36089-h)/20806)  P = P0 (0.223361)e((36089-h)/20806) T = T0 (0.751865) r  = r0 (0.297076)e((10999-h)/6341.4) P = P0 (0.223361)e((10999-h)/6341.4) 3 32 km T = T0 (0.682457 + h/945374)  r = r0 (0.978261 + h/659515)-35.16319   P = P0 (0.988626 + h/652600)-34.16319 T = T0 (0.682457 + h/288136)   r = r0 (0.978261 + h/201010)-35.16319 P = P0 (0.988626 + h/198903)-34.16319 4 47 km T = T0 (0.482561 + h/337634)   r = r0 (0.857003 + h/190115)-13.20114  P = P0 (0.898309 + h/181373)-12.20114 T = T0 (0.482561 + h/102906) r = r0 (0.857003 + h/57944)-13.20114 P = P0 (0.898309 + h/55280)-12.20114 5 51 km T = T0 (0.939268)  r = r0 (0.00116533)e((154200-h)/25992  P = P0 (0.00109456)e((154200-h)/25992 T = T0 (0.939268) r = r0 (0.00116533)e((46998-h)/7922  P = P0 (0.00109456)e((46998-h)/7922 6 71 km T = T0 (1.434843 – h/337634) r = r0 (0.79899 – h/606330)11.20114 P = P0 (0.838263 – h/577922)12.20114 T = T0 (1.434843 – h/102906) r = r0 (0.79899 – h/184800)11.20114 P = P0 (0.838263 – h/176142)12.20114

Conversion factors:

Length: 1 m = 3.281 ft

Temperature: R = 1.8 K             K = °C + 273.16            R = °F + 459.69            °F=1.8 °C + 32

Density:   1 slug/ft3  = 515.38 kg/m3

Pressure: 1 lb/ft2 = 47.88 N/m2