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Use of some ECMWF products at SMHI. Mikael Hellgren, Head of the Forecast Office Anders Persson, Research Department, NWP Section. EPS-mean. Total cloudiness: white 0-3/8 light grey 4-6/8 dark grey 7-8/8 Precipitation: Mean value over 12 hours. Prec in 67 % of all EPS members
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Use of some ECMWF products at SMHI Mikael Hellgren, Head of the Forecast Office Anders Persson, Research Department, NWP Section
EPS-mean Total cloudiness: white 0-3/8 light grey 4-6/8 dark grey 7-8/8 Precipitation: Mean value over 12 hours. Prec in 67 % of all EPS members dashed green > 0,1 mm Light green > 1 mm Dark green > 5 mm Orange > 10 mm
Precipitation: • Mean value over 12 hours. • Prec in 67 % of all EPS members • dashed green > 0,1 mm • Light green > 1 mm • Dark green > 5 mm • Orange > 10 mm
T511 ECMWF mslp 8 Feb D+5/D+6 Corresponding wave forecast ECMWF Ens. Mean mslp 8 Feb D+5/D+6 Corresponding probabilistic wave forecast
24 hour ”jumpiness” of 2 m temperature forecasts T511 Southern Sweden Ens Mean T511 Central Sweden Ens Mean Ensemble mean values not only decreases the RMS errors, but also makes the medium range forecasts much less ”jumpy”
Product from the ECMWF homepage”Total precipitation probability > 10.0 mm”
Product from the ECMWF homepage”2 metre temperature probability < 273.15 K”
Improvements in spread, and therefore in reliability, can be achieved also by (adaptive) statistical adaptation Occasions with < -20 C in Sodankylä 2003- 04 Observed T255/T511 Kalman-2 87 12 70
A recent hydrological forecast for upper parts of river Torneälv
An almost identical system is run at the Finnish hydrological agency
5-dygnsprognoser Pepparforsen Median ±25% 5-day forecasts Missing observations
5-day forecasts Pepparforsen 5-dygnsprognoser Pepparforsen Median ±50%
The explained variance around the mean, expressed as Q0=obs discharge Qc= simulated discharge Õ=obs mean discharge can be re-arranged into Affected by calibration Defined by Nature
An experiment with dynamic downscaling of EPS on HIRLAM Per Kållberg, SMHI • 7 july 2004: severe flooding in southern Sweden • ECMWF EPS (T255) as initial and boundary conditions – to 144 hours • (thanks to Roberto Buizza (ECMWF) for re-creating model level fields) • HIRLAM 6.3.7: 0.1º * 0.1º 40 levels all 50 members • run on hpcd • gridpoint version • ’cbr’ turbulence • ’straco’ condensation • ’ISBA’ soil modelling
Observed rain 9-12 July 2004
Four-day accumulated rain - ensemble mean 36 mm 40 mm hirlam 11km T255
probability of more than 40 mm in four days 40-45% 30-35% hirlam 11km T255
40 year anniversary: Since September 1965 public 1-5 day weather forecasts twice a week on TV, radio and press 1-5 days forecasts since 1965
Premiere 19 May 2005: 6-10-day weather forecasts once a week on TV
Sep 01 - Jul 03 Corr = 0.43 Y= -0.28+0.29X
With more ECMWF input From Aug 2003 Corr = 0.65 Y= -0.12+0.54X