Report on the 22nd session of the Joint Scientific Committee (JSC) for the World Climate Research Programme (WCRP),
Boulder, USA, 19-23 March 2001

Marvin Geller, SPARC Co-chair (mgeller@notes.cc.sunysb.edu)

The JSC provides overall scientific guidance for the WCRP and all the components of the Programme (the Global Energy and Water Cycle Experiment, GEWEX; Stratospheric Processes and their Role in Climate, SPARC; the World Ocean Circulation Experiment, WOCE; the Climate Variability and Predictability Study, CLIVAR; the Arctic Climate System Study/Climate and Cryosphere study, ACSYS/CLIC; the modelling activities conducted by the Working Group on Numerical Experimentation, WGNE, and the Working Group on Coupled Modelling, WGCM) were reviewed. The interactions and development of co-operation between WCRP and the other international global environmental change programmes, in particular the International Geosphere-Biosphere Programme (IGBP) and the International Human Dimensions of Global Environmental Change Programme (IHDP) were also discussed.

Both the Co-chairs of the SPARC Scientific Steering Group, Marie-Lise Chanin and Marvin Geller participated in the meeting on behalf of SPARC. A presentation was provided to the JSC on the progress being made including particularly the main conclusions and results of the Second SPARC General Assembly ("SPARC 2000") in Mar del Plata, Argentina, 6-10 November 2000 (see report in SPARC Newsletter No. 16) and the recommendations from the following session of the SPARC Scientific Steering Group in Buenos Aires, 13-16 November (also reported in SPARC Newsletter No. 16). Attention was drawn to the future directions foreseen for SPARC and the approach being planned for an integrated understanding of climate change in the stratosphere, and to a number of recent results relating to solar effects on climate.

The JSC expressed satisfaction at the work being carried out in SPARC and its continuing development. The good relationship between SPARC and WGNE in aiming to improve the representation of the stratosphere in models was particularly appreciated. The JSC especially noted the questions on the validity of the statistical analysis employed in suggesting the relationship between solar effects and land surface temperatures that were reported by M. Geller. Equally, there were questions concerning the analysis based on ISCCP data sets that had pointed to possible cloudiness variations associated with changes in solar output and cosmic rays. The JSC requested the GEWEX Scientific Steering Group to review and comment on these results. However, a more general proposal put forward by SPARC for a joint working group with SCOSTEP to assess solar influences on climate (that might also have included GEWEX and CLIVAR representatives) was not endorsed, it being considered that a further broad evaluation of this topic was not necessary at present so soon after the latest intensive IPCC discussions.

On other SPARC issues, the JSC voiced congratulations on the completion of the Water Vapour Assessment (WAVAS) (see SPARC Newsletter No. 16). The analyses in trends of ozone, temperature and water vapour carried out by SPARC had all been state-of-the-art summaries and had fed into the WMO/UNEP Ozone Assessment and into the IPCC Third Assessment. The anticipation of scientific needs in this way by SPARC was considered to be a good example for the whole WCRP. The JSC duly welcomed the study now being taken forward jointly by SPARC and SCOSTEP (together with the International Commission of the Middle Atmosphere) of upper stratospheric and mesospheric temperature trends and the SPARC participation in a workshop on ozone changes in the past decade leading up the next WMO/UNEP Assessment. The JSC also encouraged the integrated approach being developed by SPARC to see whether the different observed data variations provided a consistent picture of stratospheric climate changes (including possible trends) over the past decades (upon which shorter time-scale variations might be superimposed). Furthermore, the JSC recognised the importance of the SPARC study of gravity wave processes in the stratosphere and their parameterisation, including the construction of a stratospheric gravity wave climatology and the efforts devoted to the organisation of an international field experiment to examine the gravity-wave field forced by tropical convection (the "Effects of Tropical Convection Experiment, ECTE).

Another point raised in the SPARC report to the JSC was the dynamical coupling of the stratosphere and troposphere and the possible link between Arctic Oscillation (AO) and North Atlantic Oscillation (NAO), which appear to be different manifestations of the same underlying dynamical phenomenon. The JSC urged SPARC, CLIVAR and ACSYS/CLIC to keep the questions involved under review, but did not recommend that any (joint) specific activity be organised in WCRP at present in view of the multiplicity of workshops/symposia on this subject being arranged by the scientific community at large.

In the field of co-operation between the global environmental change programmes, the Global Change Open Science Conference in Amsterdam (10-13 July 2001) is a particular highlight. All WCRP projects and groups were strongly encouraged to attend or be represented. A significant SPARC poster cluster has been arranged, and a new SPARC brochure especially prepared. More specifically, with respect to liaison between WCRP and IGBP, it was reported by Dr. B. Moore, Chair of the IGBP Scientific Advisory Committee that a number of IGBP core projects were expected to be significantly reorganised at the end of 2002, and it is to be determined how IGBP will treat the field of chemistry in the atmosphere in the future. In this context, consideration will be given to undertaking appropriate joint WCRP/IGBP activities in the area of "Atmospheric chemistry and climate", and Susan Solomon was asked to discuss the possibilities with Guy Brasseur (present Chairman of the IGAC Scientific Committee, and Chairman-designate of the IGBP Scientific Committee). In the meantime, the importance of continuing to carry forward the existing (successful) SPARC/IGAC co-operation to ensure that planned joint activities were carried forward in a timely and organised manner, was emphasised. The SPARC/IGAC joint activities would be a principal building block of an "Atmospheric Chemistry and Climate Initiative".

The relationship between WCRP and the space agencies and the Integrated Global Observing Strategy (IGOS) was discussed. It was noted that an Integrated Global Atmospheric Chemistry Observations (IGACO) theme was now being taken up. A report on a pilot project on ozone had earlier been agreed and published, and the JSC urged that implementation of proposals laid out in the ozone report that need not wait until the wider atmospheric chemistry theme had been fully defined should proceed as rapidly as possible.

As customary at its sessions, the JSC reviewed membership of WCRP scientific steering and working groups. With regard to the SPARC Scientific Steering Group, the JSC noted with the greatest regret that M.-L. Chanin has decided to relinquish her position as Co-chair which she had held since the inception of SPARC in 1992. Great appreciation and gratitude by all present were expressed to M.-L. Chanin for her outstanding contributions, during her period of service which had result in SPARC having become such a successful activity in WCRP and very much the focus for international stratospheric science. All were reassured that WCRP and SPARC would continue to benefit from her expertise and support for a further few years in her capacity as Director of the SPARC Office. The appointment of Alan O'Neill (University of Reading, UK) as the new Co-chair of the SPARC Scientific Steering Group was welcomed. Other new members nominated were P. Canziani (University of Buenos Aires, Argentina), A.R. Ravishankara (NOAA/ERL Aeronomy Laboratory, Boulder, USA) and V. Yushkov (Central Aerological Observatory, Moscow, Russian Federation). The membership of the SPARC Scientific Steering Group thus becomes:

Membership	Expiry of appointment
M. Geller, Co-chair	31 December 2002
A.J. O'Neill, Co-chair	31 December 2002
P. Canziani	31 December 2004
C. Granier	31 December 2002
K. Hamilton	31 December 2002
D. Karoly	31 December 2002
T. Peter	31 December 2002
A. Ravishankara	31 December 2004
U. Schmidt	31 December 2002
T. Shepherd	31 December 2002
S. Yoden	31 December 2002
V. Yushkov	31 December 2004

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