JOSÉ FELIPE DA SILVA FARIASJOSÉ FELIPE DA SILVA FARIAS

AUGUSTO JOSÉ PEREIRA FILHOAUGUSTO JOSÉ PEREIRA FILHO

August 2012

The forecast of rain the very short term is very important

especially in very populated areas, helping to reduce fatalities

caused by tornadoes, storms and floods, and prevent major

damage to different sectors of society as the private,

INTRODUCTIONINTRODUCTION

damage to different sectors of society as the private,

industrial, transportation and agriculture.

Evaluate of the rainfall nowcasting within the surveillance

area of São Paulo weather radar for different types of

precipitating systems, mainly the are associated to floods

and landslides in Metropolitan Area of São Paulo, was

OBJECTIVEOBJECTIVE

and landslides in Metropolitan Area of São Paulo, was

carried out with an 2D wind advective scheme and rainfall

rates estimated by radar. The third-order upstream

numerical scheme was used with a uniform wind vector.

� Urbanization� Soild cover� Heat Island � Deeper convection over MASP

Source:www.oesteinforma.com.br

lat: 23º 36' 00" S lon : 45º 58' 20" Walt: z = 916 metros

Geographical location of the of São Paulo weather radar.

Image of the State of Sao Paulo withsatellite ACQUA obtained. A circleindicates the area of coverage of theradar. Source: Santos Filho and Pereirada Silva (2006).

� 240 Km� 33 elevations every 5 minutes� Horizontal resolution of 2 km x 2 km� Band S (10 cm)� Relation Z=200R1.6 of Marshall & Palmer (1948)

RAINFALL SHORT-TERM FORECAST

The rainfall short-term forecast was made from the displacement

vector of the precipitating system, obtained by the method

SHARP (Short - Term Automated Radar Prediction) developed

by the group of meteorology at McGill University and also used

by the Sao Paulo Weather Radar.

Linear extrapolation of radar echoes for up to 3 hours of

constant displacement vector prediction with keeping the same

structure of precipitation.

FebruaryFebruary, , OctoberOctober andandSquallSquall lineslines

NovemberNovember to to DecemberDecemberDisperse Disperse BandsBands

MayMay to to OctoberOctoberColdCold FrontsFronts

OcurrenceOcurrenceWeatherWeather SystemsSystems

.PRECIPITATING SYSTEMS

DecemberDecember e e MarchMarchSeaSea BreezeBreeze

DecemberDecember andand AprilAprilOrdinaryOrdinary ConvectionConvection

FebruaryFebruary, , OctoberOctober andandNovemberNovember

SquallSquall lineslines

Rainfall rate treshoud 20 mm/h

15

20

25N

um

ero

de

sist

emas

Convectivos

Estratiformes

0

5

10

Jan Fev Mar Abr Mai Jun Jul Ago Set Out Nov Dez

Meses

Nu

mer

o d

e si

stem

as

Number of convective e e stratiform events between 2004 - 2005.

Radar Advective Scheme

Comparison between radar and advective scheme

Field of precipitation accumulated by of São Paulo weather radar (left) and predicted by advectivescheme (right) for 30 minutes, for an event Dispersed Bands of April 21, 2005 at 07:47 (UTC).Latitudes, longitudes and geographic contours including the Sao Paulo Weather Radar andMetropolitan Region of São Paulo MRSP and municipalities are indicated. The color scales indicatethe rate of precipitation (mm).

30 minutes

60 minutes

Radar Advective Scheme

60 minutes

90 minutes

120 minutes

Radar Advective Scheme

120 minutes

180 minutes

Radar Advective Scheme

Field of precipitation accumulated by of São Paulo weather radar (left) and predicted by advectivescheme (right) for Squall lines of September 19, 2004 at 20:47 (UTC) for 30 minutes.

30 minutes

Radar Advective Scheme

60 minutes60 minutes

90 minutes

Radar Advective Scheme

120 minutes120 minutes

180 minutes

RAINFALL FORECAST SKILL

0

0,2

0,4

0,6

0,8

1

30 60 90 120 150 180

CS

IFF

LI

BD

CI

BM

0,6

0,8

1

PO

D

0

0,2

0,4

0,6

0,8

1

30 60 90 120 150 180

CS

I

FF

LI

BD

CI

BM

0,6

0,8

1

PO

D

0

0,2

0,4

30 60 90 120 150 180

PO

D

0

0,1

0,2

0,3

0,4

0,5

30 60 90 120 150 180

Tempo (min)

FA

R

0

0,2

0,4

30 60 90 120 150 180

PO

D

0

0,1

0,2

0,3

0,4

0,5

30 60 90 120 150 180

Tempo (min)

FAR

0.2 mm 2.0 mm

0

0,1

0,2

0,3

0,4

0,5

30 60 90 120 150 180

CS

IFF

LI

BD

CI

LI

0,2

0,3

0,4

0,5

PO

D

0,05

0,1

0,15

0,2

0,25

30 60 90 120 150 180

CS

I

FF

LI

BD

CI

LI

0,15

0,2

0,25

PO

D

4.0 mm 8.0 mm

0

0,1

0,2

30 60 90 120 150 180

0

0,2

0,4

0,6

0,8

1

30 60 90 120 150 180

Tempo (min)

FA

R

0,05

0,1

30 60 90 120 150 180

0,2

0,4

0,6

0,8

1

30 60 90 120 150 180

Tempo (min)

FA

R

0,02

0,04

0,060,08

0,10,12

0,140,16

30 60 90 120 150 180

CS

I

FF

LI

BD

CI

BM

0,06

0,08

0,1

0,12

0,14

PO

D

16.0 mm

0,02

0,04

0,06

30 60 90 120 150 180

0

0,2

0,4

0,6

0,8

1

30 60 90 120 150 180

Tempo (min)

FAR

CONCLUSIONSCONCLUSIONS

• The advective scheme showed better performance of the

lowest to the highest accumulations of precipitation. As for

systems with more organized structure of precipitation (LI) or

stratiform (FF);stratiform (FF);

• Systems with morphological structure more homogeneous and

more organized precipitation can be advectados for a period

exceeding 90 minutes. And convective systems 60 and 90 minutes

(in the case of convection organized).

THANK YOU!