Natalia Calvo (1), M. Hurwitz (2), M.Iza (1), C.Peña- Or<z (3), A.Butler (4), S.Ineson (5), C. Garfinkel(6), E.Manzini(7), C.

Transcription

1 DynVar workshop, Reading 2013 Natalia Calvo (1), M. Hurwitz (2), M.Iza (1), C.Peña- Or<z (3), A.Butler (4), S.Ineson (5), C. Garfinkel(6), E.Manzini(7), C.Cagnazzo(8) (1)Universidad Complutense de Madrid, (2) NASA Goddard Space Flight Center, Greenbelt ; (3) Universidad Pablo de Olavide, Sevilla; (4) Climate PredicFon Center NOAA MD; (5) Met Office, Exeter; (6) John Hopkins University; (7) Max Planck InsFtute of Meteorology, Hamburg; (8) ISAC, CNR, Roma

2 Mo<va<on ENSO is the main source of variability in the tropical troposphere It is now widely recognized that ENSO has an impact on the stratosphere. MSU T2lt (tropospheric temperatures) Calvo- Fernandez et al., 2004 (JClimate) 90º N 90ºN º S 90º E 180 º 90º W 90ºS 90ºE 180º 90ºW Calvo- Fernandez et al., 2004 (JClimate)

3 Mo<va<on Upward Wave PropagaFon, Stratospheric ENSO signal 500hPa 50hPa 3.3hPa Sassi et al. (2004), Garcia- Herrera et al. (2006), Manzini et al. (2006), Garfinkel and Hartmann (2007)

4 Mo<va<on Downward propagafon of the ENSO signal Low- top High- top ERA40 anomt anomu Manzini et al. (2006); Bronnimann et al. (2008) Cagnazzo and Manzini (2009), Ineson and Scaife (2009), Bell et al. (2009)

5 Mo<va<on Influence on surface Climate Model Reanalisis SLP SLP T surface Tsurface Precip Thompson et al. (2002), Manzini et al. (2006), Cagnazzo and Manzini (2009) Ineson and Scaife (2009), Bell et al. (2009) Amy Butler, SHFP experiments, Wednesday

6 Mo<va<on Different ENSO flavours: Central Pacific ENSO, Warm Pool ENSO, ENSO Modoki anomt Hurwitz et al. (2011 a), Zubiaurre and Calvo (2011), Hurwitz et al. (2011b).

7 Mo<va<on Different ENSO flavours: Central Pacific ENSO, Warm Pool ENSO, ENSO Modoki GEOSS- CCM QBOwest T differences between ENSO and neutral for NovDec Hurwitz et al. (2011 a), Zubiaurre and Calvo (2011), Hurwitz et al. (2011b); Garfinkel et al. (2013).

8 Ques<ons Are the CMIP5 models, atmosphere- ocean couple models, able to simulate the ENSO signal in the stratosphere as in the observafonal record? How different is the signal simultated in high top and low top CMIP5 models? Does the stratosphere play a role in NH tropospheric ENSO teleconnecfons? Are there differences between different flavours of ENSO?

9 Methodology Eastern Pacific ENSOs: N3 index > 0.1 N4 Central Pacific ENSOs: N4 index >0.1 N3 ENSO events above or below 1std from the NDJF winter mean Fme series. PiControl (100yr) and Historical (55 yr) CMIP5 simulafons. Composites made from models with more than 3 cases for Historical runs and 5 for picontrol runs. Anomalies computed wrt 100yr climatology in picontrol and for Historical simulafons. Poster Today 1209: M. Hurwitz

10 ERA40: Composites of ENSO zonal mean temperature anomalies Results EP Niño CP Niño Shading : 95% significant with a MonteCarlo test.

11 CMIP5 Models: warm ENSO Historical: NINO3 (EP Niño) in High- top and Low- top models

12 CMIP5 Models: warm ENSO Historical: NINO3 (EP Niño) in High- top and Low- top models Large warming in the NH polar region in HT models during warm EP events (Niño3). Shading regions denote where 75% of the models agree on the sign of the anomaly. PICONTROL:Weaker anomalous warming than in Historical simulafons. SFll, larger warming in the High- top models (although less agreement among models).

13 CMIP5 Results: EP vs CP Niño Historical High- Top : NIÑO3 (EP Niño) NIÑO4 (CP Niño) EP El Niño generates a stronger warming that propagates down from the upper to the lower stratosphere throughout the winter. CP El Niño generates warming in early winter that does not seem to propagate down. Anomalous cooling is simulated at the end of the winter. PICONTROL: Weaker signals, similar differences.

14 CMIP5 Results: EP Niña picontrol : High- Top NIÑA3 (EP Niña) Low- Top NIÑA3 (EP Niña) EP Niña (N3) shows an anomalous cooling over the polar cap in HT models. Stronger polar cooling and beker agreement between models in High- Top models.

15 picontrol : CMIP5 Results: EP vs CP Niña NIÑA3 (EP Niña) NIÑA4 (CP Niña) CP Niña (N4) even shows some warming in the polar stratosphere in Jan and Feb.

16 CMIP5 Results: Polar cap T differences Comparison of Temperature anomalies during ENSO events in the polar region (80-90N) at 50-80hPa: PICONTROL: Warm ENSO Cold ENSO Niño3 HT Niño4 HT Niño3 LT Niño4 LT Niña3 HT Niña4 HT Niña3 LT Niña4 LT Shading denotes 95% significant differences between N3 and N4 in HT models (red) or LT models (blue) according to a t- test.

17 CMIP5 Results: Upward wave propaga<on Winter (DJF) eddy geopoten<al height anomaly (40-60 N) Niño EP Niño CP The ridge (trough) over western Canada is stronger, and shiled eastward, for EP El Niño (La Niña) events than for CP El Niño (La Niña) Niña EP Niña CP

18 CMIP5 Results: Upward wave propaga<on Wave- 1 component of winter (DJF) eddy geopoten<al height composite for anomaly (colours) and mean (contours) East Pacific events show a more robust signal than west Pacific events The El Niño anomaly strengthens the climatological signal construcfve interference La Niña - destrucfve interference

19 CMIP5 Results: Downward propaga<on Historical High- top Models

20 CMIP5 Results: Downward propaga<on picontrol High- top Models

21 CMIP5 Results: Downward propaga<on Historical High- top vs Low- top Models: EP Niño (N3)

22 CMIP5 Results: Impact on NH climate HIGH- TOP vs LOW- TOP NegaFve AO pakern, stronger in High- Top models. Larger anomalies in T in HT models. In agreement with previous studies.

23 CMIP5 Results: Impact on NH climate HIGH- TOP CP vs EP Niño March- April Stronger signal in Nino3 than Nino4.

24 Conclusions ENSO events in HIGH- TOP CMIP5 models do generate anomalous signal in the polar stratophere in the NH. Clear significant differences between HT and LT models in this area. LT models do not simulate such a coherent signal. The polar stratospheric ENSO signal is stronger in Historical simula<ons than picontrol simulafons. Central Pacific El Niño shows a similar signal to EP El Niño in early winter but the opposite signal in late winter. Not clear downward propagafon of the signal for CP El Niño. Clear nega<ve AO pafern during warm EP El Niño. Stronger AO signal in HT models (stratosphere acfng as a bridge) in late winter in EP El Niño, and stronger than in CP El Niño.

25 Next: Work on diagnosfcs to summarize results Look at the Southern Hemisphere InvesFgate further the connecfons between SSWs and the ENSO signal. InvesFgate the role of other sources of variability on the ENSO signal.

26 1,20 SSW Frequency ,00 Frequency per yr 0,80 0,60 0,40 0,20 0,00 CSIRO- Mk3.6 MIROC5 CMCC- CM GFDL- ESM2M GFDL- ESM2G FGOALS- g2 BCC- CSM1.1 NorESM1- M HadCM3 INMCM4 MRI- CGCM3 IPSL- CM5A- LR IPSL- CM5B- LR CMCC- CESM IPSL- CM5A- MR CMCC- CMS MPI- ESM- LR CanESM2 High- top models are shown in red, low- top in blue, NNR reanalysis in black line. The majority of models underesfmate the frequency of SSWs. High- top models tend to have more SSWs than low- top models. Overall, ~6 of these models fall within +/- 0.2 SSW/yr of the observed value. This is very similar to Charlton- Perez et al. (2013).

27 y = 1,075x R² = 0,838 EN SSW Frequency (SSW/yr) 1,40 1,20 1,00 0,80 0,60 0,40 0,20 0,00 Total SSW Freq vs EN SSW Freq 0,00 0,20 0,40 0,60 0,80 1,00 1,20 Total SSW Frequency (SSW/yr) LN SSW Frequency (SSW/yr) Total SSW Freq vs LN SSW Freq 1,40 y = 1,027x 1,20 R² = 0,864 1,00 0,80 0,60 0,40 0,20 0,00 0,00 0,20 0,40 0,60 0,80 1,00 1,20 Total SSW Frequency (SSW/yr) The total SSW frequency of a given dataset is closely Fed to the EN SSW frequency. The regression value is >1, so slightly higher frequency of SSWs during EN in models relafve to total frequency. Black dot is reanalysis value. Diko for La Niña David Barriopedro, Friday Morning Blocking events, SSWs and La Niña.

28 Thank you.

29 CMIP5 Results: Impact on NH climate HISTORICAL: Dec- Jan HIGH- TOP LOW- TOP The difference bewteen high top and low top seems larger for N4 than for N3. Larger effect of N4 in early winter.