Impacts of cyclones over the Argentinean coast Claudia M. Campetella Departamento de Ciencias de la Atmósfera y los Océanos Universidad de Buenos Aires

Impacts of cyclones over the Impacts of cyclones over the Argentinean coastArgentinean coast

Claudia M. CampetellaClaudia M. Campetella

Departamento de Ciencias de la Atmósfera y los Océanos

Universidad de Buenos Aires

Argentina

Impacts of cyclones over the Argentinean coast

Impact of coastal cyclones

Natural disasters:

• Floods (positive storm surges)

• Very intense winds

• Negative storm surges

Affects the economy and industries

• Fishing industry

• Oil platforms

• Coastal management

Explosive cyclones over Explosive cyclones over

the South Atlantic Oceanthe South Atlantic Ocean

-75 -70 -65 -60 -55 -50 -45 -40 -35 -30

-60

-55

-50

-45

-40

-35

-30

-25

-20

00 UTC

-75 -70 -65 -60 -55 -50 -45 -40 -35 -30

-60

-55

-50

-45

-40

-35

-30

-25

-20

12 UTC

Explosive cyclones Possia, PhD Dissertation

200 cases200 cases

97% over ocean97% over ocean

hhPa

xdtdp

2424

sen60sen

Sanders y Gyakum (1980)

Period: 1979 – 1993

Data: ECMWF Reanalysis, 1.25ºx1.25º resol.

Distribución de ciclones explosivos por latitud (cada 4.5º)

0

5

10

15

20

25

30

35

40

45

-60 -55.5 -51 -46.5 -42 -37.5 -33

latitud

Nú

mero

de c

aso

s

seasonal meridional displacementseasonal meridional displacement

More frequent in the cold seasonMore frequent in the cold season

June to September :longer explosive June to September :longer explosive development development

Distribución mensual de ciclones explosivos

0

5

10

15

20

25

30

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

meses

Nú

me

ro d

e c

iclo

ne

s

ex

plo

siv

os

Distribución mensual de ciclones con desarrollo explosivo mayor de 24 horas

0

2

4

6

8

10

12

14

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

meses

Nú

me

ro d

e c

iclo

ne

s

ex

plo

siv

os

(t

> 2

4h

s)



Greatest explosive development

460 gpm – 59.6 hPa

in 24 hs

449 gpm – 56 hPa

in 24 hs

Black lines: initiation of explosive development

Color lines: inititation time + 24 hs


Longest explosive development

Black lines: initiation of explosive development

Color lines: inititation time + 24 hs

More than 36 hs of explosive development


The extreme cases of explosive cyclones as greatest explosive and longest development occur close the Argentinean coast.

They produce different impacts over the coastline and offshore.

It depends of the position of the cyclone center and its track

Negative storm surges in theNegative storm surges in the

Port of Buenos AiresPort of Buenos Aires

Negative Storm surges in the Port of Buenos Aires affectsNegative Storm surges in the Port of Buenos Aires affects

• navigation

• Drinking water supply of Buenos Aires city (around 6 millions people)

Negative storm surges Campetella et al, 2007, JOC


Period: 1953 – 2003

Storm surges:

oberverd hourly levels – corresponding astronomical tide level


Palermo - Noviembre 2002

Marea Observada Marea Astronómica ODT_neg -30cm

initiation end

Astronomical tide

Observed tide

Storm surge

232 cases of NSS lower than -1,20 m

35 cases of NSS lower than -1.80 m

-1.20 m

Storm surges:oberverd hourly levels – corresponding astronomical tide level


All cases

NSS < -1.80 mThe thresholds selected are related to the following risk levels:

• -1.20 m is the alert level at RDP drinking water inlets;

• which close partially or totally at -1.50 m and -1.80 m, respectively

Palermo - Noviembre 2002

Marea Observada Marea Astronómica ODT_neg -30cm

initiation end


1000 hPa mean field and anomaly (35 cases)

NCEP reanalysis

InitiationMaximum depthExtreme negative storm surges

Negative storm surges, extreme cases

Negative storm surges

Extreme negative storm surge cases reveal a well defined pattern:

A low pressure system over the east of Buenos Aires province

The associated winds direction facilities the outflow from the estuary

The type of storm surge (negative or positive) strongly depends on the cyclone location.

If the cyclone is placed to the north, it causes a river level rise (“Sudestada”).

It’s essential a good forecast of the cyclone track and intensity

Cyclones and extreme waves near the Cyclones and extreme waves near the coastcoast

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007

Servicio de Hidrografía Naval (SHN)

Knowledge of waves is important for

• industries (fishing, oil –platforms-, . . . .)

• management of coasts

• natural disasters (decision makers)

• SE winds are more efficient for the formation of extreme waves en the RDP region

• SWAN model (Simulating WAve Nearshore) is used to simulate waves in the RDP region.





• Low resolution grid: 100 x 70 points – 0.2501º x 0.1779º (22.7 km x 20.0 km)

• High resolution grid: 138 x 90 points - 0.0298º x 0.0298º ( 6.0 km x 6.0 km)



Data: Wind at 10 m (NCEP)

Batimetria



Extreme event: april 1994

Geopotential height

6 de abril (12:00 UTC)

-65 -60 -55 -50 -45

Longitud (W )

-42

-40

-38

-36

-34

-32

-30

Latit

ud (

S)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

6 de abril (8:00 UTC)

Wave height and wind



-65 -60 -55 -50 -45

Longitud (W )

-42

-40

-38

-36

-34

-32

-30

Lat

itud

(S

)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

Extreme event: april 1994

7 de abril (12:00 UTC) 7 de abril (17:00 UTC)

Wave height and windGeopotential height



7 de abril – 01 UTC

5,46 m, Punta del Este



Extreme event: May 2000

Wind and wave height (m)

16 may 1500 UTC16 may 1200 UTC

Geopotential Height



Wind and wave height (m)

17 may 1500 UTC17 may 1200 UTC

Maximum wave height: 8 m

Geopotential Height

Extreme event: May 2000



18 may 1500 UTC



6.31 m, Punta del Este

17 de mayo 21:00 UTC

Cyclones and extreme waves Possia et at, 2003, Met. Appl.

17 May 2000

•The RDP level reached a maximum of 3.52 m.

•2.50 m is the flood warning level.

•Strong “Sudestada”

SummarySummary

Lim y Simmonds, 2002, MWR

Explosive cyclones are frequent in SW south Atlantic Ocean

Explosive or not, they affect the activities over this region

Most of the cyclones that reach its maximum development over SW South Atlantic, begin over SE Brasil, Uruguay or NE Argentina.

It´s very important that NWP models may capture this previous stage

SummarySummary

THE ENDTHE END

Improve its position, track an intenstiy

It´s very important that NWP models may capture this previous stage

Documents

Impacts of cyclones over the Argentinean coast Claudia M. Campetella Departamento de Ciencias de la Atmósfera y los Océanos Universidad de Buenos Aires