Transition of WCRP projects beyond 2013: SPARC legacy and issues Christian von Savigny (IUP Bremen) on behalf of SPARC

SPARC overarching activities to be maintained beyond 2013: Chemistry-climate model validation (CCMVal) - Coordination of ongoing contribution of stratosphere-resolving chemistry- climate models to WMP/UNEP ozone assessment and IPCC ARs - Quantification of model uncertainties Assessment of key uncertainties in stratospheric and upper tropospheric measurements Linking various scientific communities: - measurement and modeling communities - stratospheric research community and the climate modeling (as in IPCC) community - synergy between organizations (WCRP, IGBP, …)

Key science questions beyond 2013 Quantify the interaction between ozone recovery and climate change Investigate air quality aspects of the troposphere-stratosphere system - changes in tropospheric chemical composition caused by stratospheric changes - increasing air traffic? Quantify the impact of solar variability (on all time scales) on climate - Dynamical and chemical response of middle atmosphere - Improve understanding of solar cycle and QBO Foster stratospheric science in climate mitigation and adaptation Elucidate the role of polar regions in global climate Quantify effects of future stratospheric change on the global carbon cycle - Stratospheric changes will affect southern annual mode, effect on CO2 uptake Critically asses Geoengineering - Thourough assessment of chemical effects of SO2 injected into stratosphere

Key aspects for model improvement Improve climate models via data assimilation - improve gravity wave drag parameterizations Improve climate models via use of mesoscale/cloud-resolving models - Focus on TTL (tropical tropopause layer) Quantify the impact of vertical domain and resolution in the middle atmosphere in climate modelling - Do limited vertical resolution and vertical range compromise climate predictability? Improve decadal stratospheric ozone predictability

Key observational issues Adapted from Steinbrecht et al., IJRS [2009] Continuity of stratospheric ozone profile satellite record in jeopardy

Courtesy of J.-C. Lambert (BIRA-IASB) Updated: September 2009 Courtesy of J.-C. Lambert (BIRA-IASB)

Key observational issues Figure courtesy of D. Fussen [2010] Number of space experiments Sentinel-4 is a GEO satellite, i.e., there will be no limb instrument on there (but UVN) Sentinel-5 is a LEO mission, but preliminary documents only list GOME/SCIA type Nadir instrumentation Sentinel-5p (launch about 2014/2015) to fill the gap between Envisat and Sentinel 4/5, has no limb instrument either.

Key observational issues No scheduled European atmospheric profiler after Envisat (operational until 2013/2014 with 3 limb sensors) U.S. missions: OMPS-Limb on NPP (launch 2011), but no OMPS limb sounder on the following NPOESS satellites To our best knowledge there is no other scheduled and funded limb mission Possible solutions: - ALTIUS, a Belgian mission (PI Didier Fussen, BIRA) ) - PREMIER, an Earth Explorer candidate mission (launch 2016 - CASS, a mission currently discussed by CSA and NASA - SAGE III on ISS (no polar coverage) SPARC contributed to the CEOS ACC recommendation for a gap- filling mission Monitoring the evolution of O3 profiles (and related chemical species) during the ozone recovery phase is of key importance Sentinel-4 is a GEO satellite, i.e., there will be no limb instrument on there (but UVN) Sentinel-5 is a LEO mission, but preliminary documents only list GOME/SCIA type Nadir instrumentation Sentinel-5p (launch about 2014/2015) to fill the gap between Envisat and Sentinel 4/5, has no limb instrument either.