A modeling study of the impact of meso-scale air sea interactions over the Gulf Stream on weather and climate

Lead Research Organisation: University of Reading
Department Name: Meteorology

Abstract

The research described in this proposal aims at assessing the impact of changes in ocean circulation on winter climate regimes over the North Atlantic and Northern Europe (these are the states in which the atmosphere resides most frequently in winter, for example, a state with a strong Jet Stream and warm humid weather over Northern Europe). To do this we will perform the first convection permitting simulations of the dominant cyclone genesis region overlying the Gulf Stream, investigating physical processes relevant to both weather and climate time scales. The approach is novel because:

(i) the oceanic forcing considered occurs on the scale of oceanic and atmospheric fronts (10-100km), upstream of the wintertime climate regimes. This physics is not currently taken into account in climate or weather forecast models.
(ii) it is rooted in an explicit study of scale interactions over the North Atlantic. The new methodology developed to tackle this interaction relies on a truly interdisciplinary collaboration between weather and climate scientists.

The major breakthrough expected from this research, if indeed sensitivity to sea surface temperature via air-sea interactions on the 10-100km scale is found, is that an untapped source of climate and weather predictability will be opened. The research agenda on this topic would also shift towards including an accurate representation of instabilities developing on atmospheric fronts and their interactions with the ocean. The research carried out in the project would provide a solid pilot study of these interactions and a model output database on which a new generation of parameterizations could be developed.

The project will also enhance the research carried in other NERC funded programmes such as DIAMET (DIAbatic Influence on Mesoscale structures in ExTra-tropical storms) by extending its relevance to the Gulf Stream region, and RAPID-WATCH (monitoring of the Atlantic ocean circulation at 26N) by providing a new pathway through which changes in ocean circulation can be communicated to the atmosphere.

Planned Impact

Three major benefiters of the project have been identified: the UK business community, the UK school teachers and the general public. Regarding the UK business community, the main effort is to translate the project's results into improved Met Office forecasts on daily, seasonal to decadal timescales since the Met office is the main provider of such forecasts to the UK community. This transfer of knowledge will be primarily achieved through the direct interaction of the two project's co-PIs with the Met Office, Woollings as leader of the Working Group on Blocking and Storm Track, and Dacre as a member of the Joint Centre for Mesoscale Meteorology.
School teachers will benefit from the project trough the "Teacher's workshop" organized by the Department of Physics at Imperial College, in association with the Institute of Physics. The project's PI will lead one session of this one-day workshop each year, offering slideshows, electronic notes and videos for the teachers to take into the classroom.
Finally, the curiosity and scientific understanding of the general public regarding the effect of the Gulf Stream on Climate will be enhanced through participation to the 2014 Summer Exhibition of the Royal Society, as well as through regular contacts with the press offices of Imperial College and NERC.

Publications

10 25 50
 
Description We have found that the cold sector of mid-latitude storms is characterised by distinctive features such as strong surface heat ?uxes, shallow convection, convective precipitation and synoptic subsidence.
Exploitation Route Our finding may be used to determine the contribution of the cold sector to the mean climate and to ocean-atmosphere coupling more generally.
Sectors Environment