Ocean and climate research at KNMI. Andreas Sterl KNMI

Transcription

1 Ocean and climate research at KNMI Andreas Sterl KNMI

2 Ocean and climate research at KNMI global and regional modelling EC-Earth RACMO Harmonie ocean observations/monitoring Argo sea level rise climate change scenarios for the Netherlands North Sea winds waves surges atmospheric chemistry data analysis (Climate Explorer; climexp.knmi.nl)

3 The climate system AR4, FAQ 1.2, Fig. 1

4 EC-Earth own climate model developed under KNMI lead state-of-the-art : resolution approx 1 degree (110 km) experimental: 1/4 degree (30 km)

5 Atmosphere GCM: IFS Land: IFS H-tessel Vegetation: LPJ OASIS3 Atmospheric Chemistry: TM5 Waves: WAM Ocean GCM: NEMO Ice sheets Carbon Cycle Sea-ice: LIM

6 The role of the ocean in the climate system reservoir of water => evaporation => precipitation (hydrological cycle) storage, transport and release of heat (large heat capacity!) => maritime vs continental climates CO2 nutrients coupled variability interaction with sea and land ice

7 Ocean productivity: the imprint of physics on biology

8 opwarming oceaan visualisatie op basis van cijfers IPCC (2007) voor

9 warmtetransport in de oceaan 50% van het totale warmtetransport vindt plaats in de oceaan thermohaliene circulatie Atlantische Oceaan naar het noorden! windgedreven gyres Stille Oceaan wervels Zuidelijke Oceaan [Trenberth and Caron, 2001] 60 S EQ 60 N

10 Ocean heat transport in EC-Earth

11 Imbalance: W/m2 GHG forcing: W/m2

12 Total heat content keeps rising Imbalance: W/m2 over 21st century

13 SST increase stops (rcp4.5 levels off)

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15 ENSO = El Niño Southern Oscillation

16 Three phases of ENSO

17 ENSO and Kelvin Waves

18 ENSO NINO3.4 index Too weak Too few (T ~5 ys in model, 3.9 ys in obs)

19 ENSO ENSO Composite Too weak Too zonal

20 zeespiegelstijging nieuw water smelten ijskappen Antarctica en Groenland smelten gletsjers en landijs veranderingen in hydrologische cyclus (rivierafvoer, bodemvocht, grondwater, stuwmeren) oud water thermische expansie 20e eeuw: ~20 cm

21 Wereldwijde zeespiegelstijging peilschalen: 18 ± 5 cm / eeuw satellieten: 32 ± 4 cm / eeuw [ ], waarvan helft uitzetting trend of tijdelijke versnelling?

22 Regional differences in sea level rise linear trend in sea level over the satellite era ( )

23 Oorzaken lokale verschillen (veranderingen in) wind patronen (veranderingen in) oceaanstromingen (veranderingen in) zwaartekrachtsveld

24 KNMI 14 climate change scenarios Local (North Sea) sea level rise between 28 and 100 cm (2100 wrt mean)

25 What is Argo? autonomous instrument probing the interior of the ocean carried horizontally by currents actively moving up and down the water column (every 10 days, 2 km) standard: T, S, p new sensors being developed 1 float per 3 x 3 box cheap (~ 100 /profile) greatly increased coverage

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28 Budgets of heat and sea level Global-mean sea level rise: SLRTotal = SLRMass + SLRSteric + SLRRes SLRTotal : total sea level rise altimeter SLRMass : glacier and ice sheet melt GRACE SLRSteric : (thermal) expansion Argo (upper 2000 m) SLRRes : residual: uncertainty + steric below 2 km

29 SLRTotal SLRMass SLRSteric(2km) SLRTotal SLRMass => steric contribution below 2 km small Llovel et al. (2014)

30 Impact of Argo on OHC estimates Without Argo, a substantial part of the OHC is missed. Durack et al. (2014, Nat. Clim. Chng.): mainly SO Balmaseda et al. (2013)

31 Dutch contribution Euro Argo member, represented by KNMI started in floats in purchased 17 working 2 to be deployed soon mainly Atlantic region recent years from cruise ship Plancius near Antarctica m/v Plancius in Antarctica Robert van Poppel, Oceanwide Expeditions

32 : from the Atlantic into the Indian Ocean

33 EC-Earth: projected change ann. mean Wspd (col); (contours). decrease, but statistically not significant

34 High winds EC-Earth rcp4.5 rcp8.5

35 Low winds EC-Earth rcp4.5 rcp8.5

36 Downscaling ann. max, 8 leden

37 RACMO - W100 daily-max wspd differences in general not significant

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39 But... EC-Earth run at high resolution (25 km), but uncoupled: Increase of the number of heavy storms, especially in early fall Frequency distribution of 3-hourly 10m windspeed Haarsma et al. (2013), GRL

40 Tropical storms in the North Sea? Haarsma et al. (2013), GRL