The CliC/IASC Workshop on Linkage Between Arctic Climate Change and Mid-Latitude Weather Extremes will be held on November 3-5, 2015, at the University of Sheffield, UK.


During the Linkages Between Arctic Climate Change and Mid-Latitude Weather Extremes Workshop, participants will review the current state of the science in view of recent publications and other recent international linkages meetings, including the SPARC Storm Tracks workshop in Grindelwald in August 2015.

The draft agenda is a review of the latest work with a circulation state dependence, limitations, and discussion of a way forward. There will be a short summary report, and organizers are open to suggestions on further publication: perhaps a commentary of some sort. The workshop will focus on variability and the fact that linkages are conditional/state-dependent. The issue of variability as a conceptual model has merit for the last decade and was brought up in the previous Seattle workshop in September 2014. A crude example is no real smooth trends in the Arctic Oscillation (AO) but large values of both plus and minus AO, especially in December. The recent Journal of Climate paper (Overland et al. 2015) section on the North Atlantic also points to variability. State dependence fits in nicely. The Arctic can thermodynamically reinforce particular circulation patterns (e.g. negative AO), but not others. Thus long-term trends in data will not pick up potential changes.


There is enough new information to warrant a review of the current state of the science in view of ICARPIII, recent publications, and recent international meetings including the SPARC storm tracks workshop in August. The focus of the Sheffield workshop is understanding the connection between Arctic forcing and internal atmospheric variability, whether linkages depend on a certain atmospheric circulation pattern (state dependence), and presenting information to a broad audience. We will provide a short summary report and discuss further publications. The issue of spatial and temporal variability as a conceptual model was brought up in our previous Seattle workshop in autumn 2014 and was the basis recent Journal of Climate paper. For example, there is no smooth trend in the Arctic Oscillation (AO) but large values of both plus and minus AO, especially in December.  State dependence needs more discussion: the Arctic may thermodynamically reinforce particular random circulation patterns (e.g. negative AO), but not others. Thus long-term trends in data will not pick up potential changes. Does the dynamics carry the chaos and multiple source regions and the thermodynamics carry the Arctic influence?

Some History

Two years ago there were the NAS and IASC workshops on linkages and the NOAA workshop in the following spring.  Not much progress was made as the controversy and differences in basic viewpoints dominated the results.

Progress was made at a small workshop in Seattle last fall that highlighted spatial variability, especially in Eastern Asia and Eastern N America. Substantial progress was made at a Polar Prediction Program (PPP) December 2014 workshop in Spain, sorting major events versus no change in cold climatology and questions of risk avoidance. The issue of state dependence of linkages was discussed at IUGG. There is emerging evidence of reinforcing mechanisms in eastern Asia and eastern North America. There is now a US CLIVAR working group and other planned activities  (e.g. Vihma).

Draft Agenda

Tuesday, November 3, 2015
9:30 AM Start
Room SR DB12 in Bartolome House


Welcome Hanna/Overland
Vihma Review Finland workshop & discussion
Screen Review, update, and discussion Can it Will it paper

Events versus no change in seasonal statistics
Null hypothesis versus risk avoidance interpretations
1st Discussion: Presenting linkage information to a broad audience: noise and other uncertainties


Shepherd – State dependence ideas (not just Arctic)
Dethloff – Sea ice and snow impacts on baroclinic-barotropic interactions
Kim – Siberian High and cold influence on Asia
Hanna – Greenland Blocking
Francis – Hemispheric scale connections: blocking and linkages to AA, AO, NAO, and PNA


Wednesday, November 4, 2015
Overland – N. America Ridge/Trough

Regional versus zonal (reduced temperature gradient) forcing
Variability and state dependency
Relative influence of the tropics and mid-latitude SST in causing the amplified jet patterns
Promising new approaches, who’s doing and will do what?

Can we develop one or more conceptual models?
2nd round: presenting information to a broad audience

Thursday, November 5, 2015
Outing to York


Please note contact details of the recommended hotel for this event:
The Rutland Hotel
452 Glossop Road
S10 2PY UK
Tel: +44 (0) 114 266 4411
Fax: +44 (0)114 267 0348

Please mention the University of Sheffield preferential room booking rate if reserving/booking a room using the phone number/reservations email as above, and the hotel staff will give you the discounted room rate of 60 GBP per night for a single room including breakfast (50 GBP without breakfast). Room availability is fine for early November, and should not be an issue as long as rooms are booked by the end of September.

Getting to the University of Sheffield and the Rutland Hotel

Getting to Sheffield
By Air: Manchester Airport is the closest and is recommended for this meeting. From the airport in Manchester, we recommend either of the following options:

By Coach/Bus: There is a dedicated coach stop within the bus station serving Terminals 1 and 2. National Express bus (route number NX350) departs for Sheffield from 8.05 am. The fare is about £7.90 and the journey takes 2-3 hours.

By Rail: A covered travellator links the rail station direct to all terminals. Trains to Sheffield depart every hour during the daytime – the fare is £18.80 (or £12.40 with a young person/student rail card) and the journey time is approximately 1 hour. Trains are safe and comfortable. Please note that travelling before 9.30 am can be more expensive. For information on train times please refer to

Getting to the Rutland Hotel

The Rutland Hotel is located at 452 Glossop Road Sheffield S10 2PY.

From the Sheffield Train Station:
Take a taxi from outside the train station is the easiest option, from directly outside the railway station.
From the Sheffield Bus Station:
From the bus station catch the number 30, 40, or 120 and ask for the Rutland Hotel, it is the stop after the Hallamshire Hospital.

Meeting organizers: Ed Hanna and James Overland