Heavy precipitationHeavy precipitationPoland under water, July 1997Poland under water, July 1997

Group 13

Convective closure Convective closure shemesshemes Domain size & resolutionDomain size & resolution

Soil moistureSoil moisture Boundary conditionsBoundary conditions

T. Spektorman (Uzbekistan)E. Vanvyve (Belgium)M. Liszewska (Poland)

The flood of July 1997 in PolandThe flood of July 1997 in PolandWroclaw

1st flood peak

2nd flood peak

What did we do ?What did we do ?

RegCMBoundary conditions

NCEP

ECMWF

Small domain40/60 km

Large domain60 km

Fritsch & Chappell

Arakawa & Schubert

PlanPlan

ResultsResults Sensitivity to convective closure schemes and boundary Sensitivity to convective closure schemes and boundary

conditionsconditions

Sensitivity to soil moistureSensitivity to soil moisture

Sensitivity to domain size and resolutionSensitivity to domain size and resolution

ConclusionConclusion

CC shemes & BCs - PCC shemes & BCs - Psurfacesurface (monthly (monthly mean)mean)

Arakawa-Schubert Fritsch-Chappell

NCEP

ECMWF

CC shemes & BCs – TCC shemes & BCs – T2m2m (monthly (monthly mean)mean)

Arakawa-Schubert Fritsch-Chappell

NCEP

ECMWF

CRU

CC shemes & BCs - precipitation (monthly CC shemes & BCs - precipitation (monthly rate)rate)

Arakawa-Schubert Fritsch-Chappell

NCEP

ECMWF

CRU

CC shemes & BCs - Precipitation (6h)CC shemes & BCs - Precipitation (6h)

Arakawa-Schubert Fritsch-Chappell

NCEP

ECMWF

Average on the flood area

PlanPlan

ResultsResults Sensitivity to convective closure schemes and boundary Sensitivity to convective closure schemes and boundary

conditionsconditions

Sensitivity to soil moistureSensitivity to soil moisture

Sensitivity to domain size and resolutionSensitivity to domain size and resolution

ConclusionConclusion

How the soil moisture can influence the How the soil moisture can influence the precipitation ?precipitation ?

Initial soil moisture in andInitial soil moisture in andaround the flood areaaround the flood areaset to 100%.set to 100%.

Precipitation for the 2 flood peaksPrecipitation for the 2 flood peaks

Sensitivity to soil moistureSensitivity to soil moisture

Sensitivity to the soil moistureSensitivity to the soil moisture1st flood peak

(4-7th July)2nd flood peak(18-20th July)

“normal”soil

moisture

“modified”

soilmoisture

1st flood peak

2nd flood peak

NCEPNCEPFritsch & Fritsch & ChappellChappell

PlanPlan

ResultsResults Sensitivity to convective closure schemes and boundary Sensitivity to convective closure schemes and boundary

conditionsconditions

Sensitivity to soil moistureSensitivity to soil moisture

Sensitivity to the domain size and the resolutionSensitivity to the domain size and the resolution

ConclusionConclusion

Sensitivity to domain size and Sensitivity to domain size and resolutionresolution

“small” domain – 60 km

“small” domain – 40 km

totalprecipitatio

n

convectiveprecipitatio

n

Average on the 3 days of the 2nd flood peak“large” domain – 60

km

NCEPNCEPArakawa & Arakawa & SchubertSchubert

PlanPlan

Simulations setupSimulations setup ResultsResults

Sensitivity toSensitivity to convective closure schemesconvective closure schemes boundary conditionsboundary conditions

Does the soil moisture matter for the peak flood ?Does the soil moisture matter for the peak flood ? Sensitivity to the domain size and the resolutionSensitivity to the domain size and the resolution

ConclusionConclusion

Preliminary conclusionPreliminary conclusion

Sensitivity to forcing fieldsSensitivity to forcing fields no difference for monthly mean Tno difference for monthly mean T2m2m and P and Psurfacesurface NCEP seems dryer than ECMWFNCEP seems dryer than ECMWF

Sensitivity to convective closure schemesSensitivity to convective closure schemes no difference for monthly mean Tno difference for monthly mean T2m2m and P and Psurfacesurface regional precipitation pattern capturedregional precipitation pattern captured flood peaks more or less corresponding to the real situationflood peaks more or less corresponding to the real situation

Sensitivity to soil moistureSensitivity to soil moisture difficult to say, more investigation neededdifficult to say, more investigation needed

Sensitivity to domain size and resolutionSensitivity to domain size and resolution more detailed convective precipitation pattern for higher more detailed convective precipitation pattern for higher

resolutionresolution

Thanks for your patience !Thanks for your patience !

Last words …Last words …

Our first conclusion was :Our first conclusion was :““Still a lot of very hard work and white nights …”Still a lot of very hard work and white nights …”That was true !!That was true !!

Sensitivity to CC schemes and BCsSensitivity to CC schemes and BCs

DomainDomain ““small” domain (40*50*18)small” domain (40*50*18) 60 km resolution60 km resolution

Convective closure schemesConvective closure schemes Arakawa & SchubertArakawa & Schubert Fritsch & ChappellFritsch & Chappell

Boundary conditionsBoundary conditions NCEPNCEP ECMWFECMWF

Monthly/daily pressure, temperature and Monthly/daily pressure, temperature and precipitationprecipitation