Predictability of European marine climate over seasons to decades

The underlying ocean warming trend associated with anthropogenic climate change is superimposed upon natural
variability of the climate system on interannual to multi-decadal timescales and between regions. The result is that, even
with a long-term 'anthropogenic' warming trend, in different regions there will be some decades in the future that will show
particularly strong warming while others will exhibit little change or even cooling. This shorter timescale climate change
over seasons to decades is particularly relevant to marine managers at national and international level, which has led to the
development of this Industrial CASE project between Cefas and the University of East Anglia. The collaboration brings
together academic expertise in climate modelling and prediction and government science provision in marine management
and policy advice.
Answering the question of what could happen in the future has generally been undertaken using climate projections where
a climate model run under a particular emissions scenario is used to examine plausible conditions 50 to 100 years in the
future. For instance, phase three of the Coupled Model Intercomparison Project (CMIP3) contributed the climate projections
to the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC).
In recent years studies examining both coupled atmosphere-ocean models and empirical statistical models have begun to
demonstrate the potential for skillful climate predictions on decadal time scales particularly in the North Atlantic region
associated with the Atlantic Meridional Oscillation (AMO). Furthermore, it has recently been shown that the AMO is an
important contributor to ecosystem change in the seas around UK and Ireland. Whilst remaining a number of years away the combination of improved understanding of the influence of Atlantic variability on UK marine ecosystems together with
short term 'climate' predictions presents the possibility of ecosystem forecasts on seasonal to decadal timescales becoming
part of national and international marine management.
The current phase of the Coupled Model Intercomparison Project (CMIP5) comprises long-term (century time scale)
simulations initialised from free running models as produced in previous CMIPs. However it additionally provides near-term
(decadal) forecasts that are initialised from an observed ocean state. Ten-year forecasts are produced every 5 years from
1960 to 2005, with optional additional forecasts for more recent years. The decadal forecast programme allows
contributions to CMIP5 from relatively high-resolution models. This is important in the context of the project, as it has been
demonstrated that higher resolution models have the capability to provide more regional detail than conventional
CMIP/IPCC class models.
Most of the work on decadal predictability has focussed on global and basin scale predictions, or on important outcomes for
mainstream terrestrial users. Here the student will use the output from the CMIP5 decadal forecast programme to answer
the following key questions:
(i) Are elements of the marine climate (for example, temperature, salinity, wind) predictable on the time scales (seasons to
decades) and space scales (for example, U.K. Exclusive Economic Zone, ICES Ecosystem Assessment Regions) relevant
to marine policy makers and managers?
(ii) What are the uncertainties and causes of any predictability?
(iii) What types of seasonal-decadal forecast methods are most appropriate for different marine users on different
timescales?