Mediterranean Sea in climate change and variability, and variations of the mass and heat budget. P.Lionello, S.Somot

Transcription

1 Mediterranean Sea in climate change and variability, and variations of the mass and heat budget P.Lionello, S.Somot The mass and heat balance of the MED The med sea in regional climate models SST and sal budget of the Med in the MedCORDEX simulations The med sea heat and sal budget in climate projections

2 Representation of the Mediterranean region as function of resolution Representation of bathymetry and topography of the Mediterranean region aggregating data in cells of increasing size: 0.2, 0.5, 1.25, 2.5 degs. Chapter 1, P.Lionello et al res

3 Temperature Precipitation GCM RCM GCM RCM Chapter 7, L.Li et al Rcm <-> gcm

4 regional model temperature: Climate change CC_RCM_T A1B scenario,: Seasonal (DJF, MAM, JJA, SON) map of temperature (K) climate change (difference minus ) from an ensemble of GCMs. (adapted from chapter 8 Planton et al.2012).

5 regional mode precipitation: Climate change CC_RCM_prec A1B scenario: Seasonal (DJF, MAM, JJA, SON) map seasonal precipitation (%) climate change (difference minus ) from an ensemble of GCMs. (from chapter 8 Planton et al.2012).

6 ENSEMBLES ( ) To develop an ensemble prediction system based on global and regional climate models, validated against observations and analyses Based on ARCM (B1 and CIRCE ( ) to predict and to quantify physical impacts of climate change in the Mediterranean area Based on AORCM and A1B scenario MEDCORDEX ( ) The purpose of CORDEX is to provide global coordination of Regional Climate Downscaling for improved regional climate change adaptation and impact assessment Multimodel exercise based on CMIP5 forcing It involves ARCM, AORCM, ORCM with reanalysis, historical and climate change (RCP4.5 and RCP8.5) simulation

7 Med-CORDEX: one of the 12 CORDEX initial domains at 0.44 (50 km) HyMeX MedCLIVAR FP6-CIRCE FP7-CLIMRUN ANR-REMEMBER 7

8 Hindcasts/reanalysis RCM are driven by perfect boundary conditions provided by GCM reanalysis Historical simulations RCM are driven by GCM simulations with prescribed past atmospheric composition Projections RCM are driven by GCM projections based on emission scenarios (B1, B2, A1, A2, RCP4.5, RCP8.5 )

9 The closure of the mass budget P= mm/year E= mm/year R= mm/year R-(E-P)=480± 200mm/year B= mm/year G 640 mm/year (after Schröder et al. 2012)

10 The closure of the heat budget Q NET -5W/m 2 (after Schröder et al. 2012)

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12 Air-sea flux evaluation Interannual variability hindcast using Regional Climate System Models (RCSM) Models: ERA-Int driven run, ENEA, CNRM, GUF, LMD, INSTM, IPSL Obs (Flux): NOCS, SRB-QC, SRB-GEWEX, ISCCP-FD, OAFLUX, GEBA, BRSN CNRM ENEA LMD GUF INSTM IPSL ERA-Int Shortwave (W/m 2 ) Latent heat (W/m 2 ) Net heat flux (W/m 2 ) Fig: C. Dubois CNRM

13 Air-sea flux evaluation Interannual variability hindcast using Regional Climate System Models (RCSM) Models: ERA-Int driven run, ENEA, CNRM, GUF, LMD, INSTM, IPSL Obs (Flux): NOCS, SRB-QC, SRB-GEWEX, ISCCP-FD, OAFLUX, GEBA, BRSN CNRM ENEA LMD GUF INSTMC IPSL ERA-Int CIRCE Shortwave (W/m 2 ) Latent heat (W/m 2 ) Net heat flux (W/m 2 ) Fig: C. Dubois CNRM

14 Air-sea flux evaluation Interannual variability hindcast using Regional Climate System Models (RCSM) Models: ERA-Int driven run, ENEA, CNRM Obs (Flux): NOCS, SRB-QC, SRB-GEWEX, ISCCP-FD, OAFLUX, , W/m2 SW LW LH SH Net REF1 (Sevault et al.) [183, 185] [-84, -75] [-90, -88] [-14, -6] [-5, -1] REF (Pettenuzzo et al. 2010) ERA-Int CNRM ENEA GUF LMD INSTM IPSL ( ) Fig: C. Dubois, S. Somot, CNRM 14

15 Evaluation of the Mediterranean Sea heat and salt content Interannual variability of Mediterranean Sea heat/salt content (1960-now) in ocean-stand alone hindcast simulations Model: Puertos de l Estado, MERCATOR-ENSTA, CNRM, INSTM, ENEA Obs: MEDAR/MedAtlas-II, EN3, (IMEDEA-IO, IFREMER) Med Sea 3D Heat Content ( C) Med Sea 3D Salt Content (psu) Fig: Ali Harzallah, INSTM 15

16 Evaluation of the Mediterranean Sea heat and salt content Interannual variability of Mediterranean Sea heat/salt content (1960-now) in coupled RCSM hindcast simulations Model: CNRM, INSTM Obs: MEDAR/MedAtlas-II, EN3, (IMEDEA-IO, IFREMER) Med Sea 3D Heat Content ( C) Med Sea 3D Salt Content (psu) Fig: Ali Harzallah, INSTM 16

17 RCSM evaluation: SST and SSS Interannual variability hindcast ( ) as simulated by an ensemble of fully-coupled Regional Climate System Model (RCSM) in Med-CORDEX Models: ERA-Int driven run, ENEA, CNRM, CNRM-SN, LMD, LATMOS, UnivBelgrade, UCLM-UPM Obs (SST): Reynolds OISST, Marullo OISST, Rixen/MedAtlas-II, EN3 Sea Surface Temperature ( C) Sea Surface Salinity (psu) Fig: Clotilde Dubois (Li et al. 2012, Ruti et al. submitted), CNRM 17

18 RCSM evaluation: SST and SSS CIRCE Interannual variability hindcast ( ) as simulated by an ensemble of fully-coupled Regional Climate System Model (RCSM) in Med-CORDEX Models: ERA-Int driven run, ENEA, CNRM, CNRM-SN, LMD, LATMOS, UnivBelgrade, UCLM-UPM Obs (SST): Reynolds OISST, Marullo OISST, Rixen/MedAtlas-II, EN3 Sea Surface Temperature ( C) Sea Surface Salinity (psu) Fig: Clotilde Dubois (Li et al. 2012, Ruti et al. submitted), CNRM 18

19 projections

20 WATER BUDGET Mediterranean water cycle anomalies over the period relative to Area-averaged evaporation (brown), precipitation (blue) and precipitation minus evaporation (black; P E) are based on an average of CMIP3 model runs. For P- E, the envelope of individual model anomalies and the one standard deviation interval around the ensemble mean are also shown (light grey and dark grey shading respectively). Data are six-year running means of annual mean area-averages over an area broadly defining the Mediterranean region. (a) Land-only; (b) Sea-only. Focus periods are highlighted (yellow) (adapted from Mariotti et al., 2008).

21 Seamless evolution of SST and SSS in AORCM Yearly-mean time series of the Mediterranean Sea average SST in red (in C) and SSS in blue (in psu) in an AORCM. The dashed lines are quadratic fits. Temperature and salinity curves are scaled by a factor 5 in order that their variations represent an equivalent density change (Somot et al 2008)

22 Heat loss (W/m 2 ) / Water loss (mm/d) / Wind Thorpe and Bigg 2000 Somot et al Somot et al decrease / increase / decrease +4.4 / +0.4 / decrease +2.7 / +0.4 / decrease Med Sea SST / SSS + 4 C / x C / psu C / psu MTHC Strait of Gibraltar water transport MOW Strong weakening Warming and saltening of the deep layers Strong weakening Warming and saltening of the deep layers Slight weakening Warming and saltening of the deep layers no change (1 Sv) About no change (-4%) About no change (-2%) Saltening (+0.12 psu), warming (+0.8 C), shallowing (from 1400 to 600m) Saltening (+0.45 psu), warming (+2.5 C), no change in density Saltening (+0.36 psu), warming (1.8 C), lightening (-0.1 kg.m-3) Mediterranean Sea spatial averaged changes at the end of the 21 st century compared to present climate: comparison between three published studies

23 SST Differences between the future climate ( ) and the present climate ( ) SSS

24 T100 m Differences between the future climate ( ) and the present climate ( ) S100 m

25 T1000 m Differences between the future climate ( ) and the present climate ( ) S1000 m

26 FRom Gualdi et al. 2013

27 Time series of anomalies averaged over the whole Mediterranean Sea for the heat budget components and total heat budget. The anomalies have been computed for the period respect to period AORCMs were available from the CIRCE project. The solid line represents the multi-model ensemble mean filtered to remove periods shorter than 5 years. The coloured shading indicates the levels of uncertainty (From Sanchez-Gomez et al. 2009).

28 AORCMs ( ) SW LW SENS LAT HB [-2,+4] [-6,+2] [-23,+4] [-1,+7] [-133,-21] Ensemble mean Percentages (%) of area-averaged mean changes in the Mediterranean Sea for shortwave (SW), longwave (LW), sensible heat flux (SENS), latent heat flux (LAT) and total heat budget (HB) for the period relative to

29 From Gualdi et al. 2012

30 From Gualdi et al. 2012

31 From Gualdi et al. 2012

32 Time series of anomalies averaged over the whole Mediterranean Sea for the water budget components, E - P and total water budget from the ENSEMBLES project (runoff here stands for river discharge). The anomalies have been computed respect to period From 1950 to 2050, 12 ARCMs were available, whereas that only 7 ARCMs were available until The solid line represents the multi-model ensemble mean (for 12 and 7 ARCMs) filtered to remove periods shorter than 5 years. The coloured shading indicates the levels of uncertainty (From Sanchez-Gomez et al. 2009).

33 Same previous figure.. The anomalies have been computed for the period respect to period from 5 AORCMs from the CIRCE project. The solid line represents the multimodel ensemble mean filtered to remove periods shorter than 5 years. The coloured shading indicates the levels of uncertainty.

34 Time series of water budget anomalies averaged over the whole Mediterranean Sea from the ENSEMBLES project RCMs (left) and the CIRCE AORCMs (right)

35 ARCMs ( ) E P E - P R B WB [0,+8] [-14,+4] [+6,+17] [-24,+3] [-42,+17] [+8, +35] Ensemble mean AORCMs ( ) [+1,+4] [-12,-7] [+8,+10] [-22,-10] [-10,+2] [+15,+26] Ensemble mean ARCMs ( ) [+6,+18] [-28,-4] [+15,+35] [-43,-5] [- 102,+25] [+20,+60] Ensemble mean CMIP3 ( ) [+6,+9] [-23,+2] [+11,+25] [-87,-56] [-85,-63] [+34,+42] Ensemble mean Percentages (%) of area-averaged mean changes in the Mediterranean Sea for evaporation (E), precipitation (P), E P, river discharge (R), Black Sea discharge (B) and total water budget (WB) for the periods and relative to (for the ARCMs) and relative to (for the AORCMs). (CMIP3 values are from Mariotti et al The ARCMs values are from Sanchez-Gomez et al )

36 Main results of regional projections of Med sea circulation: Future increase of water deficit, warming, weakening of THC Major issues: To improve the quality of hindcast: remove the bias in latent heat, short wave, sst, interannual variability of salinity and its trend Understand the interplay between mass and salt content changes and its effect on steric sea level Understand the role of Gibraltar Regional effect of global mass addition because of ice melting

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41 MIXED LAYER Time series of yearly maximum mixed layer depth between 1961 and 2099, obtained from NEMOMED8 ocean model simulation, under SRES A2 climate change scenario conditions. The dotted line represents the exponential fit for the different time series (after Sevault et al, 2009).