A tornado starts due to vertical air (mesocyclone) and wind shear. In the US, tornadoes usually move SW to NE. This is because tornadoes move in the same direction as the thunderstorms that start them, and SW to NE is the direction of most storms in the US. Tornadoes do happen in Brazil, but mainly in the southern section of the country. An average of 1,253 tornadoes happen per year in the U.S. (NOAA). I couldn't find a number for Brazil as they are just barely in the South American "Hall of Tornadoes," but Argentina which is near there has the second highest number per year behind the U.S. with about 300 (Wikipedia). The attached map shows the Hall of Tornadoes in South America, and Brazil is just barely inside the medium risk zone.
The statistics on the graph may not be true, it may be a possibilitiy that over the past 30 years we have just gotten better at documenting them which would make it seem as if there were more.
The three main requirements for hurricanes are: warm ocean temps (>80 degees), deep warm ocean layer (200m) in depth, and coriolis force is needed to initiate the spinning. The three main regions are: Hurricanes = atlantic and E pacific, Cyclones = Indian Ocean near Australia, Typhoons = China or Indonesia.
In the U.S. hurricanes generally move from E to W because of the Bermuda High and the Trade Winds. Brazil has only been hit by one tropical cyclone of hurricane force in recorded history. I could only find hurricane numbers by decaded but the U.S. usually sees 17.7 hurricanes per decade (cat 1-5) so that would be 1.7 per year. (Wikipedia)
The statistics on the graph may not be true, it may be a possibilitiy that over the past 30 years we have just gotten better at documenting them which would make it seem as if there were more.
The three main requirements for hurricanes are: warm ocean temps (>80 degees), deep warm ocean layer (200m) in depth, and coriolis force is needed to initiate the spinning. The three main regions are: Hurricanes = atlantic and E pacific, Cyclones = Indian Ocean near Australia, Typhoons = China or Indonesia.
In the U.S. hurricanes generally move from E to W because of the Bermuda High and the Trade Winds. Brazil has only been hit by one tropical cyclone of hurricane force in recorded history. I could only find hurricane numbers by decaded but the U.S. usually sees 17.7 hurricanes per decade (cat 1-5) so that would be 1.7 per year. (Wikipedia)
Similar to Brazil, it was difficult to find information on occurrences of tornadoes in India. There have been a number of documented cases, but I was unable to find a consolidated data set. As for hurricanes, India differs from Brazil in that the North Indian Ocean is an active region for cyclone formation. On average, about 5 cyclones occur annually in the region.
ReplyDelete