1. Ground-based Measurements Part II
Retrieving the Desired Information
Comparison Between Instruments
Satellite Validation
Toward Model-Measurement Comparison
Prepared by: Dr. Stella M L Melo
University of Toronto
14/11/2018

2. AIRGLOW
What it is?
Proxy for MLT temperature, concentration and dynamics
How we measure?
Comparing T measurements using airglow with LIDAR T measurements.
14/11/2018

3. AIRGLOW
What is it?
- “Spontaneous luminescence that rises from discrete transitions of the constituents of the atmosphere” (A. García-Muñoz, in preparation);
Has been used as proxy for atmospheric temperature, constituents and dynamics since back to the end of the 1950’s.
Main source: atomic oxygen photodissociated at higher altitudes.
14/11/2018

4. AIRGLOW O + O + M  O2*+ M  250–1270 nm bands emission
O2* + O  O(1S) + O2  nm emission
Not including ionosphere…
N + O  NO*  180–280 nm emission
H + O3  OH*(v = 6-9) + O2  500–3000 nm bands emission (excess of energy 3.3 eV)
14/11/2018

5. O2 O2 O2(b-x) 0-1 band measured by Keck I/HIRES (50 min integration)
Slanger and Copeland, 2003
14/11/2018

6. Airglow – Rocket measurements
Rocket measurements – Alcantara (20S, 440W)
14/11/2018

7. OH
Dyer et al., 1997
14/11/2018

8. 14/11/2018

9. Mars: Airglow Modeling – OH*
By A. García Muños
14/11/2018

10. Mars: Airglow Modeling – OH*
Diurnal variation
By A. García Muños
14/11/2018

11. MLT Temperature from airglow
Atmospheric temperature is a basic parameter.
Mesopause ( km)
Low temperature/low pressure
Transition from turbulent to molecular diffusion
Airglow can be used as proxy for MLT temperature
- OH vibrational bands
- well dispersed rotational lines
- extending from 400nm to 4mm
- intensity is relatively “easy” to measure
Other planets!
14/11/2018

12. AIRGLOW Precision improve:
rotational temperature
Precision improve:
- as the signal to noise ratio improves (DR/R decreases
as the difference in rotational energy of the states (Fb-Fa) increases
-> two lines that are farther apart in the spectrum will give a more precise measurement of the temperature
14/11/2018
Issues about LTE…

13. Airglow imager
Iwagami et al.,
JASTP, 2002
14/11/2018

14. MLT Temperature from airglow
Airglow (nadir) observations do not contain direct altitude information
At the end of the 80’s - narrow-band sodium lidar begun to be used to remotely measure the altitude profile of the atmospheric temperature between km
Data-set show:
bimodal character of the mesopause altitude
the occurrence of the Temperature Inversion Layer above 85 km
Lidar do not normally provide information about the horizontal structures
14/11/2018

15. Lidar T profile LIDAR – Light Detection and Range
Normally Lidar technique is used to measure Rayleigh scattering from which air density distribution is obtained.
By assuming hydrostatic and local thermodynamic equilibrium atmospheric temperature profiles can be calculated from the molecular backscatter profile.
Measurements are reliable form 30km up to 80 km altitude
Upper mesosphere: Na Lidar
Na fluorescence cross-section is 14 orders higher than the Rayleigh-scattering cross-section at 589 nm
Technique first proposed by Gibson et al., 1979
More on LIDAR? Carlo’s poster!
14/11/2018

16. Lidar T profile – Energy levels NaD2 lines
- Doppler-broadened fluorescence spectra of NaD2 transition.
14/11/2018
She et al., Applied Optics, 1992

17. Lidar T profile
14/11/2018
Melo et al., 2001

18. Compare Lidar and OH* Temperature
First proposed by von Zahn et al. (1987) - determine OH* altitude
OH* layer at 86  4 km
differences in temperature sometimes of up to 10 K
influence of:
clouds
differences in field of view
fast motions of the OH* layer due to gravity waves
assumed OH* layer shape
14/11/2018

19. Lidar and OH* Temperature
She and Lowe (1998) compared temperature measured with lidar (Fort Collins) and from OH airglow (FTS):
Shape OH profile taken form WINDII measurements
Generally, OH* rotational temperature can be used as a proxy of the atmospheric temperature at 87 ± 4 km
14/11/2018

20. Observations at Fort Collins (41N, 105W)
November 2-3, 1997
Nocturnal average: Lidar ~ 30 K > OH*
At 4.38 UT: Lidar 65 K > OH*
14/11/2018

21. Airglow Model Photochemical model O3+H  OH+O2 (3.3 eV)
O + O2 + M  O3 + M
OH(n) + O  H + O2
OH(n) + O2  OH(n-1) + O2
OH(n) + N2  OH(n-1) + N2
OH(n) OH(n-n) + hn
(Based on Makhlouf et al. 1995)
14/11/2018

22. Comparing Model and Observations
14/11/2018

23. OH* Rotational Temperature - Observations
OH* response to a gravity wave based on Swenson and Gardner (1998) Lz ~ 25 km
14/11/2018

24. Reed and Chandra (1975) parameterization
GCC Summer School
Recovering Mesospheric Atomic Oxygen Density Profile
from Airglow Measurements
Reed and Chandra (1975) parameterization
Upper mesosphere-lower thermosphere
[O]z = [O]max * EXP (0.5 {1.0 + (Zmax - Z) / SH - EXP((Zmax - Z) / SH)})
14/11/2018
Melo et al, 2001

25. Nightglow emissions - 80-110 km
OI Green line
O(1S 1D)
O2 Atmospheric bands
O2 (b1Sg+  X3Sg-)
OH Meinel bands
OH(X3Pn’  X3Pn” )
O+O+M O2*+M
O2*+O O(1S ) + O2
O2*+O O2+O2
O(1S )+O O +O2
O + O + M O2*+M
O2* + O O2(b1Sg+)+O2
O2* + O O2 + O2
O2(b1Sg+ )+M Prod.
H + O OH* + O2
OH* + M Prod.
O + O2 + M O3 + M 2 3
[O]
[O] [M] 2
[O] [M] 2
IO2 
[O] [M]
IOH 
IOI 
14/11/2018

26. Recovering Mesospheric Atomic Oxygen Density Profile
from Airglow Measurements
O-parameters recovered from the technique (solid line) compared to the input (dashed lines).
14/11/2018

27. Recovering Mesospheric Atomic Oxygen Density Profile
from Airglow Measurements
Atomic oxygen density profiles (atoms/cm3) input (a) compared to retrieved (b) and the percentage difference (c).
14/11/2018

28. TOH
TO2
14/11/2018

29. Measured by WINDII (symbols) and calculated (line)
Hydroxyl Profile
Measured by WINDII (symbols) and calculated (line)
( )
14/11/2018

30. Airglow Imaging Systems for Gravity Wave Observations in the Martian Atmosphere
Stella M L Melo and K. Strong, University of Toronto
R. P. Lowe and P. S. Argall University of Western Ontario
A. Garcia Munoz, J. McConnell, I. C. McDade, York University
T. Slanger and D. Huestis, SRI International, California, USA
M. J. Taylor, Utah State University, USA
K. Gilbert, London, Canada
N. Rowlands, EMS Technologies
Picture by Calvin J. Hamilton
14/11/2018

31. Mars Airglow REmote Sounding - MARES
GCC Summer School
Mars Airglow REmote Sounding - MARES
MARES-Ground is a zenith-sky imaging system for ground-based observation of wave activity in the Martian atmosphere through measurement of the contrast in images of selected airglow features.
MARES-GWIM is a satellite-borne nadir-viewing imager which will produce static images of wave-induced radiance fluctuations in two vertically separated night airglow layers in the atmosphere.
- GWIM has been developed for Earth’s atmosphere
- MARES-GWIM will be an adaptation of GWIM for the Martian atmosphere.
14/11/2018