Presentation on theme: "Contribution by Philippe Keckhut, Service d’Aéronomie/IPSL Chantal Claud, Laboratoire de Météorologie Dynamique/IPSL An updated analysis of stratospheric."— Presentation transcript:
Contribution by Philippe Keckhut, Service d’Aéronomie/IPSL Chantal Claud, Laboratoire de Météorologie Dynamique/IPSL An updated analysis of stratospheric temperature trends
Lidars StationLatitudeLongitudeOperating since Hohenpeissenberg47,80°N11,02°E1987 OHP: Obs de Haute-Provence 43,93°N5,71°E1979 Table Mountain Facility 34,04°N117,70°W1988 Hawaï19,54°N155,58°W1993 La Réunion21,80°S55,5°E1994 Table 1. List of lidar stations used in this study
The multi-parameter regressions (AMOUNTS) ( Hauchecorne et al., 1991; Keckhut et al., 1995) To evaluate temperature trends and variability (for data and model outputs): It is necessary to parametrize the variability: T(t) = m + St + ATrend + BSolar + CQBO + DENSO + EAO + Nt The A, B, C, D, E terms represent the amplitude of trends / factors of variability; (! Volcanic eruptions) The residuals (AR(1)) include all the variability not considered in the parametrization. The analysis of the residual terms : model inadequacies the degree of confidence of the analysis
Solaire SOI QBO (B. Naujokat) Indice AO: Thompson and Wallace, 1998 Les facteurs de variabilité de la température stratosphérique
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
Response to solar cycle at low latitudes, photochemical response at high and mid- latitudes, negative response with a strong seasonal dependence Role of the dynamics?
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
Solar cycle/ conclusions Equatorial response close to the photochemical response (1-2 K) Negative response at mid and high latitudes with a strong seasonal effect The solar response is strongly related to wave activity
Concerning the future… - a new Phd student should work on trends from September 2006 on: methodology, temperature satellite retrievals, and trend updates. - Europeen project Geomon (IP, P.K. coordinator deputy): ground- satellite synergy for trend estimates (can be seen as a european contribution to SPARC). - work on solar influence on the low stratosphere: observations ( FUB, MSU4, SSU) + Rose-Reprobus simulations. - study of the solar influence using LMDz-Reprobus including an interactive chemistry (a 20 years run is available) + extension to the mesosphere.