The MJO and Arctic Air Temperatures Gabriel A. Vecchi and Nicholas A. Bond JISAO, University of Washington and NOAA/Pacific Marine Environmental Laboratory Madden-Julian Oscillation connects to DJF Arctic Air Temperatures. O(3-10 Degrees C) Statistical connection is significant and robust. Both radiative and advective processes appear to drive air temperature changes. Vecchi, G.A. and N.A. Bond 2003: “The Madden-Julian Oscillation and Northern Hemisphere High Latitude Surface Air Temperatures”, submitted to Geophys. Res. Lett.

Introduction MJO is dominant mode of large-scale tropical intraseasonal variability. Connections have been found to precipitation along west coast of USA. e.g. Higgins and Mo 1997, Mo and Higgins 1998, Jones 2000, Bond and Vecchi There are circulation anomalies in high- latitudes. e.g. Mo and Higgins 1998, Bond and Vecchi 2003.

MJO and Pacific NW Precip.

Composite MJO Z500 Anomaly (m)

MJO Index 850 hPa winds from NCEP/NCAR reanalysis (post-1979) 1 st and 2 nd EOFs of Intraseasonal near- equatorial wind combined to generate MJO index (based on Shinoda et al. 1998, Bond and Vecchi 2003) Divide MJO cycle into 8 Phases, based on angle of EOF1 and EOF2. Index available online at:

Composite wintertime MJO 850 hPa zonal wind and OLR anomalies. MJO composite

Arctic Air Temperature Data Daily minimum temperature data from stations in Alaska, Canada and Keflavik, Iceland. ( ) Daily mean temperature data from stations in former U.S.S.R. ( ) Daily mean temperature data from station in Sermilik, Greenland ( ).

Location of station data used in analysis

MJO and North American SAT December-February Alaska, Canada, Sermilik (Greenland) and Keflavik (Iceland) data over Composite for each MJO Phase SAT Anomaly. Estimate significance using Student’s-t test at 90%. Also composite NCEP/NCAR extended reanalysis 500 hPa height and 700 hPa specific humidity anomalies.

Phase 5 Composite Circulation anomalies consistent with radiative and advective processes controlling SAT anomalies. Cool (Warm) SAT under low (high) 700 hPa humidity. Dry (cold) air over Alaska associated with flow from Siberia. Moist (warm) air in Canada associated with poleward flow.

MJO and Global Arctic SAT December-February Alaska, Canada, Sermilik (Greenland), Keflavik (Iceland), and former USSR data over Composite for each MJO Phase SAT Anomaly. Estimate significance using Student’s-t test at 90%. Also composite NCEP/NCAR extended reanalysis 500 hPa height and 700 hPa specific humidity anomalies.

Phase 7 Global Composite Circulation anomalies consistent with radiative and advective processes controlling SAT anomalies.

Phase 2 Composite

Composites are robust (stationary) Over N. America composite is generally the same for periods , and Over USSR composites ~same for 6 year subperiods of (not significant)

There are also circulation anomalies over northern Europe

Connection appears limited to northern winter

Summary Madden-Julian Oscillation connects to Arctic Air Temperatures. –O(3-10 Degrees C) Statistical connection is significant and robust. Both radiative and advective processes appear to drive air temperature changes. Association between MJO and Arctic SAT could be exploited for outlooks in 1-3 week timescale. Vecchi, G.A. and N.A. Bond 2003: “The Madden-Julian Oscillation and Northern Hemisphere High Latitude Surface Air Temperatures”, submitted to Geophys. Res. Lett. Contact: or

Caveats MJO definition used here is diagnostic, not prognostic…need to somehow forecast MJO. Monitored real-time at CPC. Extrapolations from current state being made by Matt Wheeler at Australia’s BOM. Limited period of analysis: for North America for former USSR) Period of analysis dominated by warm ENSO and positive PDO conditions

Future work…. What mechanisms connect tropics to Arctic? What is sensitivity of mechanisms and connections to background state? Example of Arctic Oscillation:

MJO SAT signal is on same order as AO signal

AO Appears to impact character of MJO related signal Phase 2 Temp and Z500 Composites

AO Modulates MJO associtations in global Arctic

Summary Madden-Julian Oscillation connects to Arctic Air Temperatures. –O(3-10 Degrees C) Statistical connection is significant and robust. Both radiative and advective processes appear to drive air temperature changes. Association between MJO and Arctic SAT could be exploited for outlooks in 1-3 week timescale. Vecchi, G.A. and N.A. Bond 2003: “The Madden-Julian Oscillation and Northern Hemisphere High Latitude Surface Air Temperatures”, submitted to Geophys. Res. Lett. Contact: or