1. www.reading.ac.uk 1 REACT4C Workpackage 1: Definition of Meteorological Case Studies Emma Irvine, Keith Shine, Brian Hoskins Progress Meeting, Munich, January 2012

2. 12.01.11 Structure Workpackage objectives and status Results from year 2: North Atlantic Weather types Proxies for climate impact Contrails Results from year 2: Tropical Atlantic Weather types (why we couldnt find any…) Contrails Summary REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

3. 12.01.11 Overall objective of WP1: Definition of Meteorological Case Studies The main objectives of WP1 were: Generation of ECHAM data DONE Classify weather patterns over the north Atlantic to generate a set of typically occurring weather types. DONE Sept 2010 Determine the frequency of each weather type DONE Oct 2010 Sensitivity analysis DONE Jan 2011 Classify weather patterns over the tropical Atlantic to generate a set of typically occurring weather types. DONE May 2011 Determine the frequency of each weather type DONE Aug 2011 Sensitivity analysis DONE Nov 2011 REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

4. 12.01.11 North Atlantic: Key Results Identified commonly occurring weather types, 5 for winter and 3 for summer: The weather types can be characterised by the strength and location of the jet stream, resulting in different time-optimal route locations Using simple proxies, we demonstrated that the climate impact associated with flights through each type should be different. (Irvine et al. 2012, Meteorological Applications, in press) The probability of forming a persistent contrail varies both with weather type and altitude (Plan to write up for publication Spring 2012) REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

5. The time-optimal route latitude is related to the jet stream latitude EASTBOUNDWESTBOUND REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

6. Winter weather types are characterised by the jet stream 1.Strong zonal jet 2.Strong tilted jet 3.Weak tilted jet 4.Strong confined jet Eastbound Westbound Irvine et al., 2012, Met. Apps., in press 6

7. Climate impact proxies by winter weather type for eastbound and westbound routes Contrails: distance where Rhi >100%, T<233K Jet: S=strong, W=weak, Z=zonal, T=tilted, C=confined CO 2 : route time H 2 O: time in stratosphere NO x : weighted average of time at each latitude

8. Cold ISSR frequency over North Atlantic at different altitudes, DJF 1989-2010 300 hPa, FL300250 hPa, FL340200 hPa, FL390 Overall, the frequency of cold ISSRs decreases with altitude Maxima: storm track, Greenland Minima: Hudson Bay – stratospheric polar vortex REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine

9. NEW! ISSR frequency varies by both altitude AND weather type… 300 hPa250 hPa200 hPa W1: strong, zonal jet %

10. 300 hPa250 hPa200 hPa W1: strong, zonal jet W2: strong, tilted jet % NEW! ISSR frequency varies by both altitude AND weather type…

11. 300 hPa250 hPa200 hPa W1: strong, zonal jet W2: strong, tilted jet W3: weak, tilted jet W4: confined jet % NEW! ISSR frequency varies by both altitude AND weather type…

12. …Probability of contrailing along a route varies by weather type, altitude and direction 12 Flying higher forms LESS contrails (type W1, eastbound and westbound) Flying higher forms MORE contrails (types W2 and W3 eastbound) REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine

13. 12.01.11 Tropical Atlantic: Key Results NO distinct weather types could be identified! Using proxies, the variation in climate impact is likely to be largest for contrails (note we did not try to compute a proxy for NO x ) The locations where contrails form varies with the location of convection – both a diurnal and sub-seasonal and seasonal variations controlled by different processes on different timescales REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

14. 12.01.11 REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine Andes Jet Stream South Atlantic 30°N 10°N 10°S 30°S DEEP- TROPICS SUB- TROPICS Influence of mid-latitude weather systems ITCZ convection SACZ ITCZ convection Influence of trailing cold fronts from mid-lats L North Atlantic Oscillation, East Atlantic pattern Affect jet stream position, weather systems Madden-Julian Oscillation Period 30-60 days, cycle of suppressed then enhanced convection ENSO Irregular, 3-8 years, El Niño suppresses convection, La Niña enhances convection What controls the variation in the weather on flight routes to South America?

15. Ice-supersaturation (and contrails) is related to areas of convection (Not shown: Note that ECHAM shows a much greater frequency of ice- supersaturation than ERA-Interim) 12.01.11 REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine

16. 12.01.11 REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine Climatological winds and great circle routes to South America JANUARY JULY Flights to eastern South America are less affected by variation in the wind strength (e.g. jet stream) than flights to western South America

17. Timeseries of route time, and correlation between them for DJF 2009-10 17 Router Sao Paulo – Bogota 0.13 Sao Paulo – Lima0.23 Bogota – Lima0.76 Router Sao Paulo – Bogota 0.38 Sao Paulo – Lima0.53 Bogota – Lima0.83 The lack of correlation means we cannot classify types according to long route times (high CO 2 impact) and short route times (low CO 2 impact) REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine

18. Recommendations for choosing case studies for the Tropical Atlantic Consider DJF and JJA separately Select case studies by randomly picking days (disadvantage – may not capture the full range of climate impacts) Consider flights to eastern and western South America separately. For each group of flights, cases could then be chosen on the basis of: High CO 2 impact (long route time) Low CO 2 impact (short route time) High contrail impact (lots of contrails formed) Low contrail impact (few contrails formed) 12.01.11 REACT4C Second Progress Meeting, 17-18 Jan 2012 WP1 K Shine

19. 12.01.11 Summary North Atlantic Identified weather types: 5 for winter and 3 for summer The types can be characterised by the strength and location of the jet stream, resulting in different optimal route locations The climate impact associated with flights through each type should be different Tropical Atlantic No distinct weather types could be identified! Using climate impact proxies the distance contrailing showed the greatest variation Provided recommendations for how to choose case studies REACT4C First Progress Meeting, 17-18 Jan 2012 WP1 K Shine

20. 12.01.11 REACT4C First Progress Meeting, 17-18 Jan 2011 WP x, Workpackage Leader

21. 12.01.11 WP1: Definition of Meteorological Case Studies Management Overview Deliverables scheduled in year 2011 D1.3 – achieved D1.5 – achieved D1.7 – achieved Partners and researcher scheduled in year 2011 UREAD – Keith Shine, Emma Irvine, Brian Hoskins UKMO - Helen Wells, Paul Agnew, Andrew Mirza DLR – Christine Fr ӧ mming, EUROCONTROL – Peter Hullah Resources: Effort: REACT4C First Progress Meeting, 17-18 Jan 2011 WP1 K Shine

22. The jet stream latitude is related to the North Atlantic Oscillation 22 +ve -ve From: http://www.ldeo.columbia.edu/res/pi/NAO/ NAO +ve = northerly jet stream NAO -ve = southerly jet stream ERA-Interim meteorological re-analysis data from 1989-2010

23. Comparison of optimal route and NAT track latitudes at 40W 23 REACT4C First Progress Meeting, 17-18 Jan 2011 WP1 K Shine

24. Climate impact varies with route location, weather and season 18 February 201026 January 2010 Flight entirely in stratosphere produces no contrails Flight mostly in troposphere produces persistent contrails Flight level tropopause contrails