Presentation is loading. Please wait.

Presentation is loading. Please wait.

Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986.

Similar presentations


Presentation on theme: "Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986."— Presentation transcript:

1 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986

2 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Arne Melsom, met.no

3 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Conclusions taken from the presentation from the first OPNet-meeting: A preliminary finding is that the present ensemble underestimates variability The presentation was sketchy and not very focussed =>much work to do!

4 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Model set-up 20 km model 4 km model (10 member ensemble) air/sea momentum & heat fluxes from ECMWF products ice concentrations by met.no’s ice service climatology as the 20km model OBC 8 tidal constituents added to the 4km BC climatological runoff

5 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Data for validation Vardø Rørvik Gimsøy NW Bear Isl. W Fugløya- Bear Isl. Vardø N Hydrography (IMR, WOD) Sea levels

6 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Vardø Rørvik Stationσ obs σ mod-obs Vardø Rørvik Sea level raw data/results Stationσ obs σ mod-obs Vardø0.19 Rørvik de-tided data/results mean SSH corr(ΔSL Vardø, ΔSL Rørvik ) = 0.67

7 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 IMR hydrographic transects TransectCruises/ year Stations/ cruise Gimsøy NW214 Bear Isl. W113 Fugløya – Bear Isl. 620 Vardø N.422

8 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Transect/sourcebiasσ Gimsøy NW Bear Isl. W Fugløya – Bear Isl Vardø N World Ocean Datab Transect/sourcebiasσ Gimsøy NW Bear Isl. W Fugløya – Bear Isl Vardø N World Ocean Datab Salinity (0, 10, 20, 30m) Temperature (0, 10, 20, 30m)

9 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Transect#obs (1986) 0 m20 m50 m Gimsøy NW Bear Isl. W Fugløya – Bear Isl Fugløya – Bear Isl Vardø N Salinity

10 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 S mod -S clim ; S clim >34.8, surface …the model is salt-deprived; Why? nesting problem? No! …problem orginates from 20km model bias

11 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Probability density functions (Aug-Nov) salinity (0, 10, 20, 30m)

12 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 temperature (0, 10, 20, 30m)

13 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Ensemble variability & flow instabilities Let y m be a result from ensemble member m; split: y m = y + y + y m ′ Then, (y m -y) 2 = y 2 + σ y ′ 2 and let r = σ y ′ 2 / (y m -y ) 2 ^~ ~ ^ ~

14 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Sea ice and ensemble variability

15 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Results from ranking assume e.g. S obs (x 1,y 1,z 1,t 1 ) = S e.1 (x 1,y 1,z 1,t 1 ) = S e.2 (x 1,y 1,z 1,t 1 ) = S e.3 (x 1,y 1,z 1,t 1 ) = S e.4 (x 1,y 1,z 1,t 1 ) = …this observation has rank 2 Transect/source Gimsøy NW28 Bear Isl. W56 Fugløya – Bear Isl.432 Vardø N.220 World Ocean Datab #observations

16 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Transect/sourcef

17 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 Summary Sea level:major fronts above continental slope high-frequency variability OK low-frequency variability poor Salinity:model values are too low model range is too low very high cost function in Atlantic Water Temperature: warm bias in model (generally) moderate cost functions Ensemble:low ensemble variability high flow instability impact off Lofoten

18 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986

19 Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986 time axis ‘+12 forcing’: time axis ‘+24 forcing’: Construction of ensemble From atmospheric forecasts models: an time axis an hr later: an hr later:.


Download ppt "Norwegian Meteorological Institute met.noValidation of a 4km model ensemble for 1986."

Similar presentations


Ads by Google