Earthsky Interviews
Private: South Atlantic Hurricanes
12-14-2004 - Earth
_Alex Garcia: Hi, my name is Alex Garcia. Here’s my question:_ Why aren’t there any hurricanes in the South Atlantic Ocean?
_JB:_ Alex, hurricanes can occur in the South Atlantic. A storm system scientists are calling a combination hurricane/tropical cyclone killed three people and destroyed 200 homes in Brazil last March. But South Atlantic hurricanes are rare.
_DB:_ To make a hurricane, you need warm ocean water and weak, uniform winds overhead. If the wind increases too quickly or changes direction with height – that is, if there’s wind shear – then the hurricane is torn apart before it can start. In the South Atlantic, the water is generally cooler. There’s more wind shear, so hurricanes can’t organize.
_JB:_ Also, the tropical North Atlantic has what’s called the “intertropical convergence zone,” where the trade winds from the northern and southern hemispheres converge. This special zone stays near or north of the equator throughout the year – a result of there being more land mass in the northern hemisphere than the southern. It spawns thunderstorms that can coalesce to form a hurricane – and it helps supply rotation to hurricanes.
_DB:_ The result is that most hurricanes happen in the North Atlantic. Thanks for your question, Alex. And with thanks to the “National Fish and Wildlife Foundation”:http://www.nfwf.org/, we’re Block and Byrd for Earth and Sky.
Come see Earth & Sky’s Photo Gallery: “Eyewitness photos from inside a hurricane”:http://208.96.63.114/?p=2502.
Websites of interest:
National Weather Service – “National Hurricane Center”:http://www.nhc.noaa.gov/
“Hurricane Hunters – the 53rd Weather Reconnaissance Squadron”:http://www.hurricanehunters.com/
“Hurricane and Storm Tracking for the Atlantic and Pacific Oceans”:http://hurricane.terrapin.com/
Miami Museum of Science – “Hurricane Main Menu”:http://www.miamisci.org/hurricane/
NOAA Satellite Services Division – “Hurricane Catarina, 2004″:http://www.ssd.noaa.gov/PS/TROP/catarina.html
NASA Earth Observatory Newsroom – “Rare South Atlantic Tropical Cyclone”:http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16498
NASA Earth Observatory Newsroom – “”Hurricane” Catarina Strikes Brazil”:http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16505
The following people were interviewed for today’s program. Our thanks to:
Dr. Courtney Schumacher
Assistant Professor
Department of Atmospheric Sciences
Texas A & M University
Dr. John W. Neilsen-Gammon
Professor and Texas State Climatologist
Department of Atmospheric Sciences
Texas A & M University