Impacts of cyclones over the Argentinean coast Claudia 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 the South Atlantic Ocean

00 UTC12 UTC Explosive cyclones Possia, PhD Dissertation 200 cases  200 cases  97% over ocean Sanders y Gyakum (1980) Period: 1979 – 1993 Data: ECMWF Reanalysis, 1.25ºx1.25º resol.

 seasonal meridional displacement  More frequent in the cold season  June to September :longer explosive development Explosive cyclones Possia, PhD Dissertation

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

Explosive cyclones Possia, PhD Dissertation Longest explosive development Black lines: initiation of explosive development Color lines: inititation time + 24 hs More than 36 hs of explosive development

Explosive cyclones Possia, PhD Dissertation 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 the Port of Buenos Aires

Negative 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

Negative storm surges Campetella et al, 2007, JOC initiation end Astronomical tide Observed tide Storm surge 232 cases of NSS lower than -1,20 m 35 cases of NSS lower than m m Storm surges: oberverd hourly levels – corresponding astronomical tide level

Negative storm surges Campetella et al, 2007, JOC All cases NSS < m The thresholds selected are related to the following risk levels: m is the alert level at RDP drinking water inlets; which close partially or totally at m and m, respectively

initiation end Negative storm surges Campetella et al, 2007, JOC 1000 hPa mean field and anomaly (35 cases) NCEP reanalysis Initiation Maximum depth Extreme 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 coast

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. Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN)

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Low resolution grid: 100 x 70 points – º x º (22.7 km x 20.0 km) High resolution grid: 138 x 90 points º x º ( 6.0 km x 6.0 km)

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Data: Wind at 10 m (NCEP) Batimetria

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Extreme event: april 1994 Geopotential height 6 de abril (12:00 UTC) 6 de abril (8:00 UTC) Wave height and wind

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Extreme event: april de abril (12:00 UTC) 7 de abril (17:00 UTC) Wave height and wind Geopotential height

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) 7 de abril – 01 UTC 5,46 m, Punta del Este

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Extreme event: May 2000 Wind and wave height (m) 16 may 1500 UTC 16 may 1200 UTC Geopotential Height

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) Wind and wave height (m) 17 may 1500 UTC 17 may 1200 UTC Maximum wave height: 8 m Geopotential Height Extreme event: May 2000

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) 18 may 1500 UTC

Cyclones and extreme waves Campos et al, 2007 – Martin et al, 2007 Servicio de Hidrografía Naval (SHN) 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 m is the flood warning level. Strong “Sudestada”

Summary 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

Summary THE END Improve its position, track an intenstiy It´s very important that NWP models may capture this previous stage