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NRLMSIS 2.0: New Formulation, New Data
Acknowledgement: This work was supported by the Chief of Naval Research and by NASA
Many, many thanks to the data providers!
John Emmert, Doug Drob, David SiskindSpace Science Division, Naval Research Lab
Mike PiconeVoluntary Emeritus Program, Naval Research Lab
1) NRLMSISE‐00 History and Formulation
2) NRLMSIS 2.0 Data and Formulation
3) NRLMSIS 2.0 Results
NRLMSIS History• The Mass Spectrometer and Incoherent Scatter radar model (MSIS) was created in
1977 by Alan Hedin at Goddard Space Flight Center, based in large part on Atmospheric Explorer data.
• It grew out of a 1974 statistical model of Ogo 6 mass spectrometer data.• MSIS originally represented the upper thermosphere. Upgrades followed:
• 1983: Rocket data, extended to lower thermosphere• 1986: DE‐2 data, atomic nitrogen added, expanded formulation• 1990: Extended to ground
• After Alan Hedin retired from NASA in 1995, Mike Picone of NRL’s Space Science Division continued development of the model with Alan’s assistance.
• The current version, NRLMSISE‐00, added mass density from satellite drag, O2 data from solar occultation, and a new “anomalous O” species above 500 km.
MSIS papers are top 3 cited papers in JGR Space Physics
MSIS Applications• Prediction of geophysical conditions at specific times• Distilled view of the historical observational record• Benchmark for assessing new measurement techniques and first‐principles models
• Boundary and initial conditions for first‐principles models• Interpolation among sparse observations• Attribution of observed variations• First guess (Bayesian prior) for measurement retrievals• Background conditions for other models (e.g., wave propagation)
Temperatures at 90 km over Mohe, China (54N, 122E) from MSIS (left) and a Meteor Radar (right). From Liu et al., JGR, 2017
NRLMSISE‐00 OperationGTD7 ‐ Gets Temperature and Density: GTD7(IYD,SEC,ALT,GLAT,GLONG,STL,F107A,F107,AP,MASS,D,T)
Input:IYD YEAR AND DAY AS YYDDD (day of year from 1 to 365 or 366; year ignored)
SEC UNIVERSAL TIME (s); should be consistent with GLONG and STL
ALT GEODETIC ALTITUDE (km)
GLAT GEODETIC LATITUDE (degrees)
GLONG GEODETIC LONGITUDE(degrees)
STL LOCAL APPARENT SOLAR TIME (hours)
F107A 81 day AVERAGE OF F10.7 FLUX (centered on day DDD)
F107 DAILY F10.7 FLUX FOR PREVIOUS DAY
AP 7‐element array: Daily Ap, ap(t), ap(t‐3h), ap(t‐6h), ap(t‐9h), Ap(12‐33h), Ap(36‐57h)First element used when SW(9) = 1, all elements used when SW(9) = ‐1
MASS MASS NUMBER; 48 for all, 0, for temperature, 1 for H, 2 for He, 14 for N, etc.
Output:1 2 3 4 5 6 7 8 9
D = Number Density (cm‐3) He O N2 O2 Ar
(g/cm3)H N Hot O
T = Temperature Tex T(z)
Asymptotic temperature profile defined by exospheric temperature Fully mixed hydrostatic equilibrium below ~100 km Diffusive equilibrium (~species hydrostatic equilibrium ) above ~200 km Approximate hydrostatic equilibrium between 100 and 200 km Temperature profile constructed so that the integral can be computed in closed‐form
Number Density
O2
N2
ON
HeH
Solar Min
Solar Max
Diff
usiv
e Eq
uilib
rium
Fully Mixed
Asymptotic Temperature
0
00
0
1ln ln ln mgTn n dT k T
0
0,0
0
1ln ln 1 ln ii i
m gTn n dT k T
NRLMSISE‐00 Physical Constraints
Ref. Ideal gas Hydrostatic
Ref. Ideal gas Hydrostatic(w/thermal diff)
NRLMSISE‐00 Formulation Vertical temperature profile (17 parameters)
• Cubic splines in 1/T below 120 km (14 parameters)• Bates profile above 120 km (Tex, T120, )
Species density parameters (8 per species)• Reference density (1)• Mixing ratio relative to N2 (1)• Turbopause height (1)• Corrections for dynamic flow and chemistry (5)
Expansion of vertical parameters (up to ~140 per param.)• Associated Legendre fns in latitude (up to degree 6)• Polynomials in daily and 81‐day average solar activity
(F10.7) up to order 2• Intra‐annual harmonics up to semiannual• Local time harmonics up to terdiurnal (migrating tides)• Time history of geomagnetic activity (ap index) via heating function• Longitude harmonics up to order 1 • Universal Time harmonics up to order 1
Total number of nonzero model parameters: ~1280 Limitation: Important nonmigrating tides not included.
120 120
120 120
exp
Shape factorex ex
ex
T T T
T T T
Em
mer
t, A
dv. S
pace
Res
., 20
15
NRLMSISE‐00 Data
Satellite Drag: Orbit‐derived, accelerometer
()
Alti
tude
(km
)0
100
20
0
3
00
400
500
600
1960 1970 1980 1990 2000
Mass Spectrometer
(T, ni)
Incoherent Scatter Radar (T)
ISR (T)
Occul‐tation(O2)
MAP tables (~CIRA‐86)
Misc RocketISR (T)
Reanalysis (T, P)
Lidar (T)
Infrared
(T, n
i)
Ultraviolet (T, n
i)
Microwave (T)
Occultatio
n (T)
New Data for NRLMSIS 2.0:Orbit, accelerometer, ISR, and:
New Data• NOAA meteorological reanalyses in the troposphere/stratosphere.
• Extensive new temperature and composition data in the mesosphere and lower thermosphere (incl. TIMED/SABER, Aura/MLS, ACE, AIM/Sofie, Odin/OSIRIS, Lidar).
• Extensive new orbit‐derived and accelerometer densities, UV remote sensing data, and ground‐based FPI temperaturesin the thermosphere.
1) NRLMSISE‐00 History and Formulation2) NRLMSIS 2.0 Data and Formulation3) NRLMSIS 2.0 Results
NRLMSIS 2.0: Formulation Changes
NRLMSISE‐00 NRLMSIS 2.0
Temperature Profile Continuity C1 Continuous C2 Continuous
Transition from fully mixed to diffusively separated
Geometric average of mixed and diffusive profiles
Height‐dependent effective mass
O profile near and below peak
Hyperbolic tangent (logistic) function
Above 85 km: Modified Chapman function
Below 85 km: Cubic splines decoupled from T
Thermal Diffusion Applied to H, He, Ar
Not used: Incompatible with static representation,
inadequately supported by data
Fourier expansion fitting parameters Amplitude and Phase Sine and cosine coefficients
Altitude representationGeopotential height differences between
geometric reference heights
Internally uses global geopotential height function
Transition from Fully Mixed to Diffusively SeparatedNRLMSISE‐00 NRLMSIS 2.0
260
220
180
140
100
60
20
1
2828.95
AA Ad m
s
n n n
Am
0
00
0
ln ln ln1 R R
effH
MgT Rn n dT k T e
Mixed nmDiffusive ndMerged
log nN2
Ref. Ideal gas Hydrostatic Topside Corr.(O2, He, H)
Effective Mass (Meff) transitions from 28.9 amu to species massEffective Mass (Meff) transitions from 28.9 amu to species mass
Merged profile: weighted averageof diffusive andmixed profiles
12
Problems with merged profile in NRLMSISE‐00 (fixed in 2.0)
NRLMSISE‐00 Helium Effective Mass Profile
Negative effective mass Density increases with height!
Discontinuities in effective mass Density profile not C1 continuous.Discontinuities in effective mass Density profile not C1 continuous.
Geo
pote
ntia
l H
eigh
t (km
)
NRLMSIS 2.0: Test fits of O profile (5N, Day of year 150)
Daytime (14 LT) Nighttime (2 LT)
Species Hydrostatic Equilibrium with Variable Mass
Modified Chapman Layer
Cubic B Splines (decoupled from T)
0
00
0
ln ln ln expeff C
C
M Tgn n d Ck T T H
-- NRLMSISE-00 -- SABER Climatology-- Fit with MSIS above 120 km, SABER below 80 km
Ref. Hydrostatic Ideal gas Chapman term
14
NRLMSIS 2.0 Fortran Code Goals• Fortran 90• Compatible with gfortran compiler• OpenMP compatible• Speed comparable to or faster than NRLMSISE‐00
Remaining Tasks• Add geomagnetic activity• Finalize model parameters• Code and speed enhancements• Documentation
Planned Enhancements for NRLMSIS 2.1• Use other solar activity inputs besides F10.7• Add nitric oxide (NO)• Improve geomagnetic activity dependence
17
NRLMSIS 2.0 Summary Arguments: Position, time, solar irradiance, geomagnetic activity Output: T(z), Tex (K); N2, O2, O, He, H, Ar (cm‐3); (g cm‐3) Domain: Ground to exosphere
Formulation Changes Include: • Seamless transition from fully mixed to diffusive separation• New O profile, down to 50 km• C2 continuity in temperature profile
New Data Include: • NOAA meteorological reanalysis data in the lower atmosphere.• Extensive new temperature and composition data in the mesosphere
and lower thermosphere.• Extensive new orbit‐derived an accelerometer densities, UV remote
sensing data, and ground‐based FPI temperatures in the thermosphere.
Interested in using the new model (version 1.95)?Contact John Emmert ([email protected]) or Doug Drob ([email protected])