Upper stratospheric trends

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Upper stratospheric trends

Philippe Keckhut, Chantal Claud, Bill Randel
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Topics

• lidar / SSU
• Trend estimates
• Other data sets
• Solar effect

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NDACC Lidars
Station Latitude Longitude Operating since
Hohenpeissenberg 47,80N 11,02E 1987
OHP Obs de Haute-Provence 43,93N 5,71E 1979
Table Mountain Facility 34,04N 117,70W 1988
Hawaï 19,54N 155,58W 1993
La Réunion 21,80S 55,5E 1994

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OHP lidar has negligible residual trend
Hohenp. lidar has positive residual trends
anomalies in 98-00 and biais
?
TMF lidar has much larger cooling trends step
wise 2-3
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comparison of lidar and SSU trends for
1988-2005 Notes Satellite trends are small
for this period. Trends are changing Large
statistical uncertainties for the lidars (only
shown for OHP curve, but similar for other
stations). Table Mountain is an outlier (strong
cooling, as seen in the time series) Hohenpeisenbe
rg also
TMF.
OHP.
Hohenp.
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(No Transcript)
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• A new temperature trend assessment should
• Assess trends
• Time
• Altitudes
• Latitudes
• Accuracy
• trends accuracy
• temporal continuity, data consensus
• Highlighted what is new / 2001
• Trend behavior
• Changing trends
• Existing series
• new,
• combining (SSU/AMSU)
• and stopping one (FUB, rocket)
• What is required for future trends
  recommendations

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Summer OHP Lidar temperature trends
Linear 1979-1997
Linear 1979-2005
Linear term of a non linear analysis 1979-2005
Quadratic term 1979-2005
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Trends updated with rocket sondes 1969-1995
Rockets and lidar
Heiss (81N)
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Temperature climatology above Dumont DUrville
(Antarctica)
Nov-April
Aug.-Oct.
Occurrence of T lt 190K
ECMWF-RS at 100hPa for 1995-2000
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Response to the 11-year solar cycle
US Rocket sites
Tropics Sub-tropics Mid-latitudes
Kekchut et al., 2005
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Response to the 11-year solar cycle
Lidar 44N
Summer Winter
Keckhut et al., 2005
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Response to the 11-year solar cycle
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1979-1998
SSU at 6 hPa
Keckhut et al., 2005
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Mechanistic simulations of the atmospheric solar
response
3D Rose/Reprobus model at SA

• Response depends on Planetary Waves activity
• Response is highly non-linear

Clim1.5
Clim1.8
Clim2.2
Hampson et al., 2005
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Variations with Longitude
25 km
37 km
49 km
Ref Hampson et al. 2007