Modelling Support for Meridional Overturning Circulation

(MOC) Monitoring Proposals

The Announcement of Opportunity for the MOC monitoring component of RAPID states that the aim of this component of RAPID is to produce, by the end of the 6 year programme, a design for an operational monitoring system capable of providing continuous monitoring of the MOC, to facilitate detection and prediction of MOC changes, including early warning of any large, rapid changes. In order to make a clear case for long-term funding of such an operational system, it will be necessary, by the end of the programme, to have demonstrated that the system has the potential to deliver the required benefits within a timeframe relevant to end users and funding bodies. For example, a system which is likely to detect and attribute anthropogenically forced MOC changes only after it has been in place for 100 years will be of little use to the formulation of policy on greenhouse gas emissions.

A demonstration of what benefits can be realised from the operational system, and on what time scales, is likely to be part of the RAPID monitoring projects themselves. However, in view of the possible need for considerable up-front expenditure on putting prototype monitoring systems in place, the RAPID Scientific Steering Committee agreed that it would be useful if a preliminary assessment of the long term potential of proposed systems could be made by Principal Investigators (PIs) at the proposal stage. To facilitate this assessment the Hadley Centre has made available to potential PIs a preliminary analysis of the potential of a range of observations. If requested, the Hadley Centre will also work with PIs at the stage of full proposal preparation, to help address any specific questions about the long-term potential of proposed systems. PIs are not obliged to make use of this offered support, and it should be stressed that the issues that can be addressed here will form only one of a number of factors in the evaluation of proposals

A report was made available by 8th March 2002 to all potential PIs who register an interest. The report made an assessment of the expected time scales on which any unusual trends in the MOC might be detected, given time series of a large set of observable variables. The variables will include those for which time series have been collected, planned or proposed under existing programmes and co-ordination efforts (e.g. ASOF). Subsets of these variables were also considered. The assessment was based on simulated observations in control and IPCC 'B2' scenario runs of the HadCM3 coupled climate model. An assessment of uncertainties due to model deficiencies will be included. Following the assessment of outline bids, the Hadley Centre will, if requested, work interactively with PIs who have been given the go-ahead to develop full proposals, to address any further issues regarding long-term potential of the proposed observations.

The Hadley Centre will not be bidding for funds from the RAPID programme, but it has a common scientific interest with RAPID in achieving a final design for the monitoring system that meets the stated needs, and it is therefore willing to work (in confidence if requested) with any group developing proposals in this area.

Background information and preliminary results were presented at the Town Meeting on 1st February 2002, and interested PIs were invited to contact the RAPID Science Co-ordinator, Meric Srokosz (e-mail: M.Srokosz@soc.soton.ac.uk), to register an interest in the initial report.

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