EP711 Supplemental Material Thursday, January 11, 2018
EP711: Standard Atmospheres and Empirical Models
Jonathan B. Snively Embry-Riddle Aeronautical University Standard Atmospheric Models
• Describe the ambient atmospheric state under average conditions.
• May be ft (numerically or analytically) to large data sets.
• May include empirical ftting to variable solar/geomagnetic conditions, season/local-time.
• Include:
• MSISE90 / NRLMSISE00 / NRLMSIS 2.0 (Upcoming)
• US Standard Atmosphere
• COSPAR International Reference Atmosphere (CIRA)
• Horizontal Wind Model (HWM 93, 07, 14)
• Very useful as basis for simple atmospheric modeling studies, without the need to include comprehensive descriptions of chemistry and solar forcing to defne the ambient state. Regions of the 400 Space Station Atmosphere
300 Exosphere
Thermosphere 200 (And Ionosphere) Space 100 Mesopause Meteors Mesosphere Stratopause Stratosphere Ozone Tropopause 0 km Troposphere Weather Regions of the 400 ~1000 K = 1340ºF Atmosphere
Temperature 300
200 Thermosphere / Ionosphere
Mesopause 100 ~180 K = -135ºF Mesosphere Stratopause
Stratosphere Tropopause 0 km Troposphere ~289 K = 61ºF Regions of the 400 Density decreases exponentially! [N2] Atmosphere [O2] [O] Temperature 300
Composition
200 [O] Becomes Dominant
Peak of [O] Density 100 Density decreases exponentially!
0 km Regions of the Atmosphere
150 US Standard 1976 NRLMSISE-00
THERMOSPHERE
100 MESOPAUSE (~85-100 km) MESOSPHERE Altitude (km) 50 STRATOPAUSE (~50-55 km)
TROPO- STRATOSPHERESPHERE TROPOPAUSE (~10-15 km)
0 100 200 300 400 500 600 700 Temperature (K) Thermosphere and Exosphere
500 Exospheric 450 Temperature = ~1000 K
400
350
300
250
Altitude (km) 200 Mesopause Temperature 150 Minimum = ~180 K
100
50 US Standard 1976 NRLMSISE-00 0 100 200 300 400 500 600 700 800 900 1000 1100 Temperature (K) Thermosphere and Exosphere
500 500 500 (a) (b) (c) −3 450 450 450 Density (kg⋅ m ) Pressure (105 Pa) 400 400 400
350 350 350 HETEROSPHERE
300 300 300
250 250 250
200 Altitude (km) Altitude (km) 200 200 Strong Molecular Difusion Altitude (km)
150 150 150 “TURBOPAUSE” (~100-120 km) 100 100 100 HOMOSPHERE 50 50 50 Weak Molecular Difusion, “Stronger” Eddy Difusion 0 0 0 200 300 400 500 600 1.3 1.4 1.5 1.6 1.7 1.8 100 10-10 10-8 10-6 10-4 10-2 100
-1 -1 Specific Gas Constant (J kg K ) Averaged cp/cv Density or Pressure (See Legend) Summary
• Standard reference atmospheres provide useful descriptions of the ambient atmospheric state for simple modeling. These may include:
• Densities (species number and mass)
• Temperature(s)
• Horizontal Winds
• Derived parameters from standard atmospheres provide insight into typical stratifcation and stability characteristics – Next step.