Presentation on theme: "Philippe Keckhut, Chantal Claud, Bill Randel Upper stratospheric trends."— Presentation transcript:
Philippe Keckhut, Chantal Claud, Bill Randel Upper stratospheric trends
Topics - lidar / SSU - Trend estimates - Other data sets - Solar effect
NDACC Lidars StationLatitudeLongitudeOperating since Hohenpeissenberg47,80°N11,02°E1987 OHP: Obs de Haute-Provence 43,93°N5,71°E1979 Table Mountain Facility34,04°N117,70°W1988 Hawaï19,54°N155,58°W1993 La Réunion21,80°S55,5°E1994
TMF lidar has much larger cooling trends: step wise 2-3 Hohenp. lidar has positive residual trends: anomalies in 98- 00 and biais OHP lidar has negligible residual trend ?
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) Hohenpeisenberg also TMF.OHP. Hohenp.
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
Summer OHP Lidar temperature trends Linear 1979-1997 Linear 1979-2005 Linear term of a non linear analysis 1979-2005 Quadratic term 1979-2005
Trends updated with rocket sondes 1969-1995 Rockets and lidar Heiss (81°N)
Temperature climatology above Dumont DUrville (Antarctica) Nov-AprilAug.-Oct. Occurrence of T < 190K ECMWF-RS at 100hPa for 1995-2000
Response to the 11-year solar cycle US Rocket sites Tropics Sub-tropics Mid-latitudes Kekchut et al., 2005
Response to the 11-year solar cycle Lidar 44°N SummerWinter Keckhut et al., 2005
Response to the 11-year solar cycle ±70° SSU at 6 hPa 1979-1998 Keckhut et al., 2005
Mechanistic simulations of the atmospheric solar response Response depends on Planetary Waves activity Response is highly non-linear Clim*1.5 Clim*1.8 Clim*2.2 3D Rose/Reprobus model at SA Hampson et al., 2005
Variations with Longitude 25 km 37 km 49 km Ref: Hampson et al. 2007