BEIG-Trends-Upper atmospheric Climate change-FINAL MOST-2010.ppt

While the lower atmosphere is warming due to increased greenhouse gases, the upper atmosphere (above 15-500 km) is experiencing cooling, impacting neutral, ion, and electron temperatures, densities, and winds, which affects satellite safety and measurements.

1. Recent Advances in Long Term
Trends of MLT-Region
(Both Anthropogenic and Solar –A summary)
Gufran Beig
Indian Institute of Tropical Meteorology,
Pune, India
(with Special thanks to Juergen Scheer)
H
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[
k
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stratopause
mesopause
1*CO2
2*CO2
Ozone
vmr

2. Measurements of Temperature at the MLT Region over the Globe

3. (Beig & Fadnavis, 2001)
(Sridharan et al., 2009+)
INDIA
TIME FRAMES
Rocketsonde
1971-1993
Lidar
1998-2009
TEMPERATURE TRENDS
LOW LATITUDE
O
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R
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4. TEMPERATURE TRENDS: LOW LATITUDE
O
V
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R
V
IE
W
(U
p
d
a
t
e
-2
0
1
0
)

5. MESOPAUSE REGION
~ 80-100 KM

6. She et al. (2009)
Observed Long Term Trends (1990-2007) in temperature by Na-Lidar at 41
o
N
compared with 2 new Generation models SMLTM and HAMMONIA
TEMPERATURE TRENDS: MID-LATITUDE
O
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R
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7. TRENDS

8. 2003
2
0
1
0
TENDENCY

Zero
Negative
TRENDS

9. •A Break in 1996
•Cooling is faster in recent time wrt past
Offermann et al. (2010)
TRENDS
Trend = - 2.3K /decade
(1988-2008)

10. GLOBAL

SOLAR RESPONSE

11. MESOSPHERE

12. Solar Response -TROPICS
SOLAR

13. 20
30
40
50
60
70
80
-3-2-10 1 2 3 4



Solar coeff. (k/100sfu)
A
l
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(
k
m
)
Thumba (8
o
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Solar Response in The Low Latitude (India)

14. Solar Response –MID-LATITUDE
SOLAR

15. Mesopause Region

16. Observed Solar response in K/sfu (1990-2007) in temperature
by Na-Lidar at 41
o
N (Fort Collins)
She et al. (2009)
SOLAR

17. She et al. (2009)
SOLAR

18. SOLAR

19. SOLAR

20. HALOE &
New Generation
HAMMONIA
(Joint With Schmidt and Brasseur)

21. HALOE & HAMMONIA:
Tropics: Solar Response in Temperature
80
50
65
SOLAR

22. HALOE & HAMMONIA:
Mid-latitude: Solar Response in Temperature
SOLAR

23. HALOE & HAMMONIA:
Tropics: Solar Response in Ozone
SOLAR

24. CONCLUSIONS

25. Long term Trends in the MLT region
-Observations-
•Mesosphere of Tropics:
1-4K /decade
Consistently High
•Mesopause Region:
•Tendency of drift from near Zero trends to
slight negative trends.
•Some break indicators ~late 90s.
•Recent trends are more towards cooling.
•Premature to expect a clear link between
changing mesopause region temperature
trends and changing ozone.

26. Solar Response in the MLT region
-Observations-
•Recognition of positive signal in the annual mean
solar response of the MLT regions with an amplitude
of few degrees per 100sfu.
•Majority of the NH results indicate a solar response
of the order of 1-3K/100sfu near the OH-airglow
emission height for the mid-latitude which becomes
negligible near the pole.
•In the SH, a few results reported so far indicate the
existence of strong solar response near the pole and
a weak response at lower latitudes.
•There is increasing evidence for a solar component of
the order of 2-4K/100sfu in the lower thermosphere
(92-100 km) which further decreases as u go up.

27. Mesosphere
•In the Mesosphere, mid-latitude solar response of 1-3K/100sfu is
consistent with satellite, LIDAR and US-rocksonde whereas Russian
results indicates a more variable trend.
•Existence of a solar response of 1-3K/100sfu for the mesospheric
region at the tropics. Negative in the straosphere consistently
posing challenge to modellers.
•Most recent CCM model results indicate a higher upper limit of solar
temperature response as compared to observations (2 to 10 K per
solar cycle in the mesopause region), with the largest value
occurring slightly above the summer mesopause (ca. 100 km).
•Up to the mesopause, the temperature response may either be
positive or negative depending upon longitude, particularly for
middle and high latitude in winter.
Model Simulations

28. HALOE: Mesosphere
Solar Signal (1991-2004)
TROPICS
0.5K to 1.0K/100 sfu (Tropics)
MID-LATITUDE
Increases from 0.5K at 50 km to 1.5K /100 sfu at 60 km and then
again start to decrease.
LATITUDE VARIATIONS
Large. Northerm Hemispheric Solar signal is stronger than
Southern Hemispheric signal.
HAMMONIA able to capture signals near reasonable.