wg4 activities pierre eckert meteoswiss, geneva

Federal Department of Home Affairs FDHAFederal Office of Meteorology and Climatology MeteoSwiss

WG4activities

Pierre EckertMeteoSwiss, Geneva

2 COSMO General meeting ¦ Rome, September 2011Pierre.Eckert[at]meteoswiss.ch

Topics

• Guidelines for forecasters, incl. stratified verification (↔ WG5)

• Postprocessing

• Sochi Olympic games PP CORSO

• FIELDEXTRA presentation by Jean-Marie Bettems

3 Automatic weather classifications| COSMO GM 2011

Tanja Weusthoff / Pierre Eckert

New (automatic) weather classifications (MeteoSwiss) The old manual weather classifications are replaced with new

automated weather classifications.

OLDNEW

Alpenwetterstatistik AWS

Perret

Zala-KlassifikationMan

ual,

until

31.

12.2

010 GWT & CAP/PCACA

auto

mat

ed

Sin

ce J

anua

ry 2

011,

Cal

cula

ted

back

until

01.

09.1

957



1. CAP = Cluster Analysis of Principal Component

1. Neue (automatisierte) Wetterlagenklassifikationen

2. GWT = GrossWetterTypes

3. GWTWS = adapted GWT

GWT10, GWT18 and GWT26 based on (1) MSLP and (2) Z500

GWTWS with 11 classes based on GWT8 for Z500, mean wind at 500 hPa and mean MSLP

CAP9, CAP18 and CAP27 based on MSLP

10 classifications are computed every day, based on two different kind of methods

Methods



• For daily computation (since 01.01.2011), use of the operational IFS 12z run from ECMWF; Analysis and forecasts out to 10 days are classified

• Classifications computed back using ECMWF reanalyses 01.09.1957-31.08.2002 ERA40

01.09.2002-31.12.2010 ERA interim

• Domain: alpine region41N - 52N (12pts)

3E - 20E (18pts)

1. Neue (automatisierte) Wetterlagenklassifikationen

Database

6 Verification results at MeteoSwiss in 2011

COSMO GM / WG5 Parallel Session, 05.09.2011

Results for 20103h accumulated precipitation sumsover the domain of the Swiss radar composite

models: COSMO-2 and COSMO-7for all 8 daily forecast runs, precipitation sums from +3 to +6h

observation precipitation estimates of the swiss radar composit

in case of a missing value, the full date will not be evaluated

Neighbourhood verification for precipitation(MeteoSwiss, T. Weusthoff)



NE

(11x)

N

(18x)

NW

(38x)

SE

(4x)

S

(10x)

SW

(49x)

E

(4x)

W

(56x)

F

(78x)

H

(73x)

L

(25x)

COSMO-7 better COSMO-2 better

differences in Fractions Skill Score for weather-type dependant verif

COSMO-2 minus COSMO-7

YEAR 2010



Summary neighbourhood verification precipitation in 2010

• The skill of the models varies for different weather types and the differences between COSMO-2 and COSMO-7 varies also:- best skill: Autumn and Spring, south to northwest weather types- greatest difference COSMO-2 minus COSMO-7: Summer and Winter, north- and east types, convective cases

Tanja Weusthoff

9

Conditional verificationConditional verification

Flora Gofa

http://www.hnms.gr/hnms/greek/index_html

11

Percentage of weather regimes

0

5

10

15

20

25

30

Z C

Z AC

N-NWC

N-NWAC

N-NE C

N-NEAC

S-SW C

S-SWAC

S-SE C

S-SEAC

Cut-off STNAC

Per

centa

ge

%

1 2 3 4 5 6 7 8 9 10 11 12

For southerly weather situations the cloud

cover is more overestimated….

12

Weather type Dependent Verification

w.r.t. high density rainguage network

Maria Stefania Tesini

13

6-Northerly cyclonic

14

10-Central Mediterranean Low

16

Some considerations on models performances

• At low threshold (e.g. 1 mm/24h) – Cosmo Models perform well in cyclonic situations (CLM,CMT,MC) –

high TS and BIAS ≈1– ECMWF is strongly biased– In anticyclonic situation COSMO-MED and ECMWF are better in terms

of POD but they tend to overestimate the number of events• At higher thresholds (e.g. 5 m/24h and 10 mm/24h)

– COSMO-I7 and I2 miss the anticyclonic situation– still good performance for all models for the cyclonic

situations

17 COSMO General meeting ¦ Rome, September 2011Pierre.Eckert[at]meteoswiss.ch

Postprocessing

• COSMO-MOS

• Diagnostics of turbulence for aviation

• Exchange of postprocessing methods

18

Turbulence index = 1 (light) Turbulence index = 4 (moderate)

Turbulence index = 5 (severe)Colours for measurement height in [m]

Matthias Raschendorfer COSMO Rome 2011DWD

Diagnostics of turbulence for aviation, M. Raschendorfer DWD

19

Matthias Raschendorfer

Distribution between Model- and ARCAS-EDR:

- Prediction-pedictor correlation: 0.44

COSMO Rome 2011DWD

20

Matthias Raschendorfer

Final distribution after successive regression:

- 21 predictors- most effective besides edr: p, dt_tke_(con, sso, hsh)- Successive cubic regression of residuals- Prediction-pedictor correlation: 0.627- Variance reduction: 39.9 %

COSMO Rome 2011DWD

Federal Department of Home Affairs FDHAFederal Office of Meteorology and Climatology MeteoSwiss

Accounting for Change:Local wind forecasts from the high-

resolution model COSMO

Vanessa Stauch (MeteoSwiss)

ECAC & EMS, September, 14th 2010COSMO-GM, September 2011, Roma

22 Local wind forecasts | ECAC/EMS 2011, BerlinVanessa Stauch, [email protected]

Spatial verification of wind speed

Model topographyfairly complex

Model performancepretty good


Spatial verification of wind speed

Model topographyfairly complex

Model performancepretty good

Model performanceat some stationsrather poor


Accounting for change

Length of database ~

complexity of statistical correction

temporal flexibility (e.g. when model error changes)

“global MOS”

“KF”

“UMOS” “COSMO-MOS”

„global MOS “: e.g. MOSMIX at DWD, multiple linear regression based on global NWP models (GME and IFS)

“UMOS”: ‘updateable’ MOS of Canadians, weighting when model chsnges

“KF”: Kalman Filter based estimation, online update

+ Sampling for many cases, good discrimination

- A bit inert when model changes

+ insensitive to model changes

- simple error model, poor discrimination of weather condition

Need for models with few parameters

“MOS with reforecasts”


Extended logistic regression

Wilks 2009

Sam

ple

clim

atol

ogy

Wind speed

threshold

ObsFcst

lnp q

1 p q

b0 bix i

i1

n

g q

Add thresholds as predictor, estimate one additional parameter


Results: bias correction for vmax

wg4 activities pierre eckert meteoswiss, geneva

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