J. Ignacio López-Moreno: Effects of NAO on combined temperature and precipitation winter modes snow cover in Mediterranean mountains
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J. Ignacio López-Moreno: Effects of NAO on combined temperature and precipitation winter modes snow cover in Mediterranean mountains

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J. Ignacio López-Moreno: Effects of NAO on combined temperature and precipitation winter modes snow cover in Mediterranean mountains J. Ignacio López-Moreno: Effects of NAO on combined temperature and precipitation winter modes snow cover in Mediterranean mountains Presentation Transcript

  • Effects of NAO on combined temperature and precipitation winter modes andsnow cover in Mediterranean mountains: observed relationships and projections for the 21st century J. Ignacio López-Moreno nlopez@ipe.csic.es
  • IMPACT OF NAO ON WINTER TEMPERATURE AND PRECIPITATION MODES AND SNOW COVER IN THE MEDITERRANEAN MOUNTAINS - Plant and animal phenology -Tourism - Natural hazards: avalanches and floods - Water resources
  • SNOW IN THE MEDITERRANEAN MOUNTAINS Atlas Iberian peninsula Alps and Apenines Carphatians Lebanon Turkey
  • CORRELATION OF NAOi WITH WINTER (DJFM) PRECIPITATION ANDTEMPERATURE: 1950-2005 Precipitation Temperature Correlation significant at 95%
  • Objectives1- To assess the effect of NAO on combined precipitation and temperature andsnow accumulation in the Mediterranean mountains.2- To assess the capability of GCMs for reproducing the observed relationships.3- To check if simulated relationships will remain stationary or will change in thenext century due to increasing GHGs concentrations.Problem: In general snow data is scarce and not available for researchers in mostof the Mediterranean region.
  • Winter modes approach1- Warm and wet (WW): Tª>60th percentile; Precip>60th percentile2- Warm and dry (WD): Tª>60th percentile; Precip<40th percentile3- Cold and wet (CW): Tª<40th percentile; Precip>60th percentile4- Cold and dry (CD): Tª<40th percentile; Precip<40th percentile Château d’Oex, Davos, Arosa, Saentis, 1.0 DJFM mean snow accumulation (percentiles) 980 m a.s.l. 980 m a.s.l. 1850m a.s.l. 2500 m a.s.l. 0.8 0.6 0.4 0.2 0.0 WW WD CW CD WW WD CW CD WW WD CW CD WW WD CW CD
  • Winter modes approach 1- Warm and wet (WW): Tª>60th percentile; Precip>60th percentile 2- Warm and dry (WD): Tª>60th percentile; Precip<40th percentile 3- Cold and wet (CW): Tª<40th percentile; Precip>60th percentile 4- Cold and dry (CD): Tª<40th percentile; Precip<40th percentile Château d’Oex, Davos, Arosa, Saentis, 1.0 DJFM mean snow accumulation (percentiles) 980 m a.s.l. 980 m a.s.l. 1850m a.s.l. 2500 m a.s.l. 100 Château d’Oex, 980 m a.s.l. Saentis, 2500 m a.s.l. 0.8 600 80 Snow depthSnow depth 60 0.6 400 40 0.4 200 20 0.2 0 0 0 50 100 150 200 250 0 50 100 150 200 250 0.0 Day Day Warm/Wet Cold/Wet CW CD CW CD WW WD CW CD WW WD CW CD WW WD WW WD Warm/Dry Cold/Dry
  • Study area and case studies 6 8 9 14 1 3 7 11 13 2 10 4 12 15 5 1- Cantabrian M. (7) 5- Atlas (84) 9- Dinaric Alps (18) 13- N. Turkey (181) 2- Central S. (10) 6- Alps (113) 10- Pindos (23) 14- Caucasus (85) 3- Pyrenees (22) 7- Apenines (16) 11- Balkan M. (16) 15- Lebanon M. (8) 4- S.Nevada (4) 8- Carpathians (16) 12- Taurus (87)Data: CRU TS2.1 (50km grid size). Study period: 1950-2005
  • Iberian Peninsula: Pyrenees 3 1 4 López-Moreno and Vicente-Serrano (2007). Atmospheric circulation influence on the interannual variability of snow pack in the Spanish Pyrenees during the second half of the 20th century. Nordic hydrology 38 (1):38-44.
  • Iberian Peninsula: Pyrenees 3Teleconnection Snow Component 1index accumulationNAO *-0.38 *-0.39EA -0.17 0.06EA/WR -0.24 -0.04SCA 0.19 0.26* α <0.05 López-Moreno and Vicente-Serrano (2007). Atmospheric circulation influence on the interannual variability of snow pack in the Spanish Pyrenees during the second half of the 20th century. Nordic hydrology 38 (1):38-44.
  • Iberian Peninsula: Pyrenees 3 173 of 241 major avalanche events in the Pyrenees have been observed during winters dominated by negative NAOi García et al. (2009) Major avalanches occurrence at regional scale and related atmospheric circulation patterns in the Eastern Pyrenees. Cold Regions Science and Technology 59 (2009) 106–118
  • Iberian Peninsula 1- Cantabrian M. 3 2- Central S. 3- Pyrenees 4- S.Nevada 2 4Correlation between winter NAOi(DJFM) and winter precipitation and temperature 1.0 Cantabrian mountains Central System Pyrenees Sierra Nevada 0.8 0.6 Coefficient of correlation 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 -1.0 Tmn Tmx Tavg Precip Tmx Tmn Tavg Prec. Tmx Tmx Tavg Prec. Tmn Tmn Tavg Precip Tmn Tmx Tavg Precip Tmx Tmn Tavg Prec. Tmn Tmx Tavg Precip Tmx Tmn Tavg Prec.
  • Iberian Peninsula 1- Cantabrian M. 3 2- Central S. 3- Pyrenees 4- S.Nevada 2 4 WD WW 1.0NAO 0.8 -2.0 -1.5 Temperature -1.0 0.6 -0.5 Cantabrian M. Central System Central S. Pyrenees S. Nevada 0.0 0.5 0.4 1.0 1.5 2.0 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.00.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Precipitation Precipitation Precipitation Precipitation CD CW 3 Cantabrian mountains Central System Pyrenees Sierra Nevada 2 NAO (DJFM) 1 0 -1 -2 -3 WW WD CW CD WW WD CW CD WW WD CW CD WW WD CW CD Winter NAOi(DJFM) under different combinations of precipitation and temperature
  • Morocco: Atlas 1.0 Atlas 0.8 1.0 0.6 3Coefficient of correlation 0.8 Atlas 0.4 NAO 2 -2.0 0.2 Temperature NAO (DJFM) -1.5 0.6 1 -1.0 0.0 -0.5 0.0 Atlas 0 0.5 0.4 -0.2 1.0 -1 1.5 -0.4 2.0 0.2 -2 -0.6 -3 0.0 WW WD CW CD -0.8 0.0 0.2 0.4 0.6 0.8 1.0 Precipitation -1.0 Tmx Tmn Tavg Prec. Tmn Tmx Tavg Precip
  • Alps 1.0 Y Data Alps 0.8 0.6Coefficient of correlation 1.0 0.4 3 0.2 0.8 Alps NAO 2 0.0 NAO (DJFM) Temperature -2.0 0.6 -1.5 1 -0.2 -1.0 Alps -0.5 0.4 0 0.0 -0.4 0.5 -1 1.0 1.5 0.2 -0.6 2.0 -2 -0.8 0.0 -3 0.0 0.2 0.4 0.6 0.8 1.0 WW WD CW CD Precipitation -1.0 Tmx Tmn Tavg Prec. Tmn Tmx Tavg Precip
  • Apenines 1.0 Apenines 0.8 1.0 0.6Coefficient of correlation 3 0.8 Apenines 0.4 NAO -2.0 2 0.2 -1.5 Temperature 0.6 NAO (DJFM) -1.0 1 0.0 -0.5 Apenines 0.0 0 -0.2 0.5 0.4 1.0 1.5 -1 -0.4 2.0 0.2 -2 -0.6 -3 -0.8 WW WD CW CD 0.0 -1.0 0.0 0.2 0.4 0.6 0.8 1.0 Tmn Tmx Tavg Prec. Tmx Tmn Tavg Precip Precipitation
  • 1.0 Dynaric Alps Pindos Balkan M. CarpathianBalkans 0.8Carphatian 0.6 Coefficient of correlation 0.4Dynaric Alps 0.2Pindos 0.0 -0.2 -0.4 -0.6 -0.8 -1.0 Tmx Tmn Tavg Prec. Tmx Tmn Tavg Prec. Tmx Tmn Tavg Prec. Tmx Tmn TavgPrecip Tmn Tmx TavgPrecip Tmn Tmx TavgPrecip Tmn Tmx TavgPrecip Tmn Tmx Tavg Prec. 1.0 NAO 0.8 -2.0 -1.5 Temperature -1.0 0.6 -0.5 Dynaric Alps Pyndos Balkan M. Carpathian 0.0 0.4 0.5 1.0 1.5 0.2 2.0 0.0 0.0 0.2 0.4 0.6 0.8 0.0 1.0 0.2 0.4 0.6 0.8 0.0 1.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Precipitation Precipitation Precipitation Precipitation 3 Dynaric Alps Pyndos Balkan M. Carpathian 2 NAO (DJFM) 1 0 -1 -2 -3 WW WD CW CD WW WD CW CD WW WD CW CD WW WD CW CD
  • 1.0 Taurus N. Turkey Caucasus LebanonTaurus 0.8 0.6N. Turkey Coefficient of correlation 0.4Caucasus 0.2 0.0Lebanon -0.2 -0.4 -0.6 -0.8 -1.0 Tmx Tmn Tavg Prec. Tmx Tmn Tavg Prec. Tmx Tmn Tavg Prec. Tmx Tmn Tavg Prec. Tmn Tmx TavgPrecip Tmn Tmx TavgPrecip Tmn Tmx TavgPrecip Tmn Tmx TavgPrecip NAO -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 3 Taurus N. Turkey Caucasus Lebanon 2 NAO (DJFM) 1 0 -1 -2 -3 WW WD CW CD WW WD CW CD WW WD CW CD WW WD CW CD
  • ANOVA TEST WW WD CW WD CW CD CW CD CD Cantabrian M. X O O X O O Central S. X O O X O O Pyrenees X O O X X X S. Nevada X O X X O X Atlas O O X O O X Alpes O O O X X O Apenines O O O O O X Carpathian M. X O O O O O Dynaric Alps X O O X O O Pindos X O X O O X Balkans O O O O O X Taurus O O X O O O N. Turkey O O O O X O Caucasus O O O O O O Lebanon O O O O O O X diference is significant at α<0.05
  • What do the models inform for the next century?Simulated temperature and precipitation simulated for each mountain system, and NAOi forthe period 1900 and 2099 by 10 different GCMs were used to:-Asses the capability of GCMs to reproduce the observed relationship between precipitationand temperature and NAOi across the Mediterranean area-Assess if relationships between NAO and winter modes observed in the last century areexpected to continue during the 21st century SRES A1B
  • Distribution of observed (OBS) and simulated winter NAO values forthe 20th (C) and 21st (F) centuries 2.0 1.5 1.0 0.5 NAO values 0.0 -0.5 -1.0 -1.5 C F C F C F C F C F C F C F C F C F C F OBS MRI MPI MIUB MIROC GFDL CSIRO CNRM CCMA BCM UKMO -2.0
  • Simulated correlation between NAOi and precipitation for the controlperiod (1950-2006)
  • Simulated correlation between NAOi and precipitation for the controlperiod (1950-2006) and 21st century (2000-2099)
  • Simulated correlation between NAOi and temperature for the controlperiod (1950-2006) and 21st century (2000-2099)
  • Average NAOi for different winter modes during the control period (C,1950-2006) and the 21st century (F. 2000-2099) 1.5 Pyrenees Alps 1.0 Mean NAOi (DJFM) 0.5 0.0 -0.5 -1.0 C F C F C F C F C F C F C F C F WW WD CW CD WW WD CW CD -1.5 1.5 Pindos Lebanon 1.0 MRI MPI MIUB Mean NAOi (DJFM) 0.5 MIROC GFDL CSIRO 0.0 CNRM CCMA BCM UKMO -0.5 Model average Observed -1.0 C F C F C F C F C F C F C F C F WW WD CW CD WW WD CW CD -1.5 WW WW_F WD WD_F CW CW_F CD CD_F
  • Number of GCMs which show significant differences in NAOi accordingto different winter modes during the control period (1950-2006) and21st century (2000-2099) WW WD CW WD CW CD CW CD CD Cantabrian M. 4 0 3 6 1 1 Central S. 6 0 5 6 0 4 Pyrenees 6 0 1 7 4 4 S. Nevada 5 0 7 5 2 5 1950-2006 Atlas 2 3 9 0 3 3 Alpes 1 1 0 6 5 1 Apenines 2 1 4 4 0 1 Carpathian M. 5 1 0 2 1 0 Dynaric Alps 6 2 0 1 0 1 Pindos 5 1 6 0 1 2 Balkans 0 1 4 0 1 1 Taurus 0 1 2 1 2 1 N. Turkey 0 1 1 0 1 2 Caucasus 0 2 1 0 0 0 Lebanon 0 2 2 1 2 0 WW WD CW 2000-2099 WD CW CD CW CD CD Cantabrian M. 8 2 2 8 3 3 Central S. 8 1 7 9 2 7 Pyrenees 9 2 3 10 2 7 S. Nevada 8 0 8 8 1 9 Atlas 5 2 8 3 2 7 Alpes 7 1 3 8 7 4 Apenines 7 1 2 7 3 4 Carpathian M. 8 3 2 9 3 4 Dynaric Alps 9 0 4 6 1 6 Pindos 8 0 8 3 3 3 Balkans 2 1 4 2 3 4 Taurus 0 2 5 1 4 2 N. Turkey 0 1 2 1 1 0 Caucasus 1 2 4 1 1 0ANOVA TEST Lebanon 0 3 5 0 3 2
  • Change in temperature and precipitation simulated by 10 GCMs 2000-2099 period compared to 1950-2000 3.5 Temperature 3.0 Change in temperature (ºC) 2.5 2.0 1.5 1.0 MRI 0.5 40 MPI Precipitation MIUB 30 MIROC Change in precipitation (%) 20 GFDL 10 CSIRO CNRM 0 CCMA -10 BCM UKMO -20 -30 Model average Observed -40 Cant.M. S.Cent. Pyr. S.Nev Atlas Alps Apen. Carp. Dyn.A. Pynd. Balk. Taur. N.Turk.Cauc. Leb
  • Change in the number of winters belonging to different winter modesduring the 21st using the percentiles of the period 2000-2099 (C) and1950-2000 (F) 30 Cold and wet 25 Number of winters 20 15 10 5 0 CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF 35 Cold and dry MRI 30 MPI 25 Number of winters MIUB 20 MIROC 15 GFDL CSIRO10 CNRM 5 CCMA 0 BCM CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF UKMO Cant.M.S.Cent. Pyr. S.Nev Atlas Alps Apen. Carp. Dyn.A. Pynd. Balk. Taur. N.Turk. auc. Leb C Model average
  • Change in the number of winters belonging to different winter modesduring the 21st using the percentiles of the period 2000-2099 (C) and1950-2000 (F) 100 Warm and wet Number of winters 80 60 40 20 0 CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF 100 Warm and dry MRI 80 MPI Number of winters MIUB 60 MIROC GFDL 40 CSIRO CNRM 20 CCMA BCM 0 CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF UKMO Cant.M.S.Cent. Pyr. S.Nev Atlas Alps Apen. Carp. Dyn.A. Pynd. Balk. Taur. N.Turk. auc. Leb C Model average
  • Conclusions NAO exerts a strong influence on the occurrence of different winter modes across the mediterranean area - In the Iberian Peninsula, Atlas, Balkans and Greece it mainly causes differences between wet and dry modes. - In the Alps, Taurus and Lebanon NAO introduce significant differences between cold and warm modes The occurrence of winter modes has a major influence on the accumulation of snow in the mountain areas. Hence, NAO pattern is an important driver of the interannual variability of snowpack. 0.2 3 NAO (DJFM) 2 A 0.0 Pearson´s correlation coefficient 1 µ = -0.36 0 4 B -1 -0.2 Snow depth (-) -2 2 -3 3 0 µ = -0.48 Snow depth (-) -0.4 2 1 -2 0 r= - 0.59 -0.6 -1 -4 p< 0.05 -2 -3 -2 -1 0 1 2 Values above de average -0.8 Values below the average NAO (DJFM) Number of Number of Number of cases: 86 cases: 24 cases: 62 -1.0 All snow poles Snow poles Snow poles below 2100 m above 2100 m
  • Conclusions GCMs have shown a reasonable skill for reproducing NAO variability, most of simulations project an increase in NAO for the next decadesGCMs reproduce adequately the observed correlations between NAO and precipitationacross the basin, and they have a lower capability for reproducing correlations withtemperature. In general, the influence of NAO in the ocurrence of contrasted wintermodes is well simulated. Such influence tends to be maintained, even strengthed in thenext decades.These results suggest that the projected upward trend of NAO in the next decades maylead to higher frequency of winter modes unfavourable for snowpack developmentAn expected increase of temperature (1.5-2ºC) will cause that the number of cold(warm) winters as observed during the 1950-2000 period will decrease (increase)dramatically in the 21st century.
  • Conclusions Thanks!