april 2005: 19 nws/ 21 forecast products (1) austria aladin-lace (9.6 km) arpege

1Deutscher WetterdienstMärz 2005

April 2005: 19 NWS/ 21 forecast products

(1) Austria ALADIN-LACE (9.6 km) ARPEGE

(2) Czech Repub ALADIN-LACE (9 km) ARPEGE

(3) Croatia ALADIN-LACE (9 km) ARPEGE

(4) Hungary ALADIN-LACE (11 km) ARPEGE

(5) Slovakia ALADIN-LACE (11 km) ARPEGE

(6) France ALADIN (11 km) ARPEGE

(7) Belgium ALADIN (15 km) ARPEGE

(8) Slovenia ALADIN (9.5 km) ARPEGE

(9) UK UM-EU/LAM (20/12 km) UM-global

(10) Denmark HIRLAM (16 km) ECMWF

(11) Finland HIRLAM (22km) ECMWF

(12) Netherlands HIRLAM (22 km) ECMWF

(13) Spain HIRLAM (22 km) ECMWF

(14) Ireland HIRLAM (16 km) ECMWF

(15) Norway HIRLAM (22/11 km) ECMWF

(16) Switzerland aLMo (7 km) ECMWF

(17) Italy EuroLM (7km) EuroHRM

(18) Germany LM (7 km) GME

(19) Poland Institute of Meteorology and Water Management

SRNWP-PEPSa regional multi-model ensemble in Europe

Internet: www.dwd.de/PEPS

Jean Quiby

Sebastian Trepte

Michael Denhard

[email protected]

[email protected]

[email protected]


Generation

PEPS grid with a grid spacing of 0.0625° (~7 km) covering Europe

The ensemble size depends on location and every PEPS grid point has its own probability distribution

thresholdaisandpointgridatforecastsofnumbertotaltheiswhere

)(

TiN

N

iatTexceedingxforecastsofNumberTxP

i

ii

Methodology

Ensemble


Ensemble Products

4. Ensemble size per grid point (at least two members)

1. Ensemble mean. Forecast periods +06...+30h (24 hours), +06...+18h and +18...+30h (12 hours)

• Total precipitation (accumulation), sum of convective and large scale precipitation• Total snow (accumulation) ), sum of convective and large scale snow• Maximum 10 m wind speed• Maximum 10 m wind gust speed• 2 m minimum/maximum temperature

2. Probabilistic products. Forecast period +06...+30h (24 hours)

• Probabilities of total precipitation Thresholds: > 25, > 40, > 70 mm• Probabilities of total snow Thresholds: > 1, > 5, > 10, > 20 cm• Probabilities of maximum wind speed Thresholds: > 10, > 15, > 20, > 25 m/s• Probabilities of maximum wind gust speed Thresholds: > 10, > 15, > 20, > 25, > 33 m/s

3. Probabilistic products. Forecast periods +06...+18h and +18...+30h (12 hours)

• Probabilities of total precipitation Thresholds: > 20, > 50, > 100 mm • Probabilities of total snow Thresholds: > 1, > 5, > 10, > 20 cm • Probabilities of maximum wind speed Thresholds: > 10, > 15, > 20, > 25 m/s• Probabilities of maximum wind gust speed Thresholds: > 10, > 15, > 20, > 25, > 33 m/s


Maximum Ensemble Size

MaximumEnsemble Size

Totalprecip.

Totalsnow

Windspeed

Wind gustspeed

Temperature

00 UTC 20 19 20 8 20

06 UTC 7 6 7 - 7

12 UTC 20 19 20 8 20

18 UTC 8 7 8 1 8

depends on main run and on meteorological parameter


Ensemble Mean

21/01/2005 00 UTC +06...30


21/01/2005 00 UTC +06...30

probability forecasts


Cut-off times

Model run cut-off time

00 UTC 05.30 UTC

06 UTC 11.30 UTC

12 UTC 17.30 UTC

18 UTC 23.30 UTC

SRNWP-PEPS runs operationally since December 2004 (Distribution of forecasts to the contributing NWS)


The SRNWP-PEPS project

SRNWP-PEPS workshop 6th April 2005, ARPA-SIM, Italy

products validation further developement rights of use


Workshopproducts

Mask of areas without sufficient models

Wind gusts

provided by COSMO and some ALADIN countries using different parametrisationsstatistical estimation of wind gusts within PEPS?

Statistics of availability of models

Additional productsmore sysoptic oriented parametersindices of convectivity

Precipitationmedian instead of meanlower thresholds

PEPS-Meteograms (provided by Meteoswiss)


validation

Workshop

• Comparison with COSMO-LEPS

• Scoring probabilistic forecasts- error measures- FBI, POD, FAR, ETS, HSS, Odds Ratio- BS, BSS, RPS, ROC

• Scale-/Object oriented techniques

- contiguous rain area method (Ebert &McBride)

• Severe weather Problem

- linear error in probability space (LEPS)

• Online verification

WG on Verifcation to coordinate verification with high resolution observations in the contributing countries and to provide scientific expertise.


further developement

Workshop

Ensemble Calibration

Calibrated: Intervals or events that we declare to have probability P happen a proportion P of the time

Sharp: Prediction intervals are narrower on average than those obtained from climatology; the narrower the

better

Dressing the probability distriubtion of the ensemble with observational errors and give different weights to the ensemble members



Workshop

Using Bayesian Model Averaging (BMA) to calibrateforecast ensembles

„The model is estimated from a training set of recent data by maximum likelihood using the EM algorithm. Good results with a 25-day training period.“

Adrian E. Raftery, Fadoua Balabdaoui, Tilmann Gneiting and Michael PolakowskiDepartment of Statistics, University of Washington, Seattle, Washington

),y~()~,...,y~|p(y 2k1 kk

kkn bawy

is the observed value

is the k th forecast

y

1y~



Workshop

BMA

work on precipitation is in progress

Software R package EnsembleBMA is available

Sourcewww. stat. washington. edu/ rafterywww. stat. washington. edu/ MURI



Workshop

The SRNWP-PEPS consits of different model grids with different horizontal and vertical resolutions.

Question:How can we account for these differences in an appropriate way ?

Statistical downscaling ?

Neighbourhood Ensemble ?



Workshop

Neighbourhood Ensemble ?consider all gridpoints within a given distance of a point

Size of Area

Form of Area

spatial temporal

x

t

Neighbourhood members from different grids should not have equal weightsSystematic errors (e.g. due to orography) should be corrected



Workshop

Hybrid LAM-Ensemble ?concatenate SRNWP-PEPS with other ensemble systems

• COSMO-LEPS

• INM Ensemble• Meteo France PEACE Ensemble• UK-Met Office LAM• met-norway LAMEPS

Concerning GLOBAL PEPS:„According to most skill measures, these hybrid configurations outperform the ECMWF-EPS at short range for most variables, regions and thresholds“from: Test of a Poor Mans Ensemble Prediction System for short range probability forecasting Arribas, A., Robertson, K.B., Mylne, K.R.


research projects using PEPS forecasts & products

Workshop

Hydrological Ensemble Forecasts for the „MULDE“ catchment

Hybrid Ensemble

COSMO-LEPS (+120h)

SRNWP-PEPS (+48h)

LMK (2.8km)"lagged average forecast"

Ensemble(+18h)

consistent forecast scenarios of precipitation for the Mulde catchment

up to +120h

International projects which use or may use SRNWP-PEPS forecasts

- EURORISK Prev.I.EW windstorms workpackage- MAP D-Phase (Mesoscale Alpine Program)


rights of use

Workshop

Scientific use products as well as individual forecastshistoric as well as live data

Commercial useproducts only

Request to DWDDWD distributes the request to the contributing NWS

NWS give their permission

products have to be added to the ECOMET list withpermission of the NWS


any questions or remarks ?

Thank you to all contributing Weather Services !

april 2005: 19 nws/ 21 forecast products (1) austria aladin-lace (9.6 km) arpege

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