2 replies to this topic

[Rick Santos]

What are the biggest reasons Manaus and Belem are always warm, compared to latitudes right at the Tropic of Cancer ? Is it the sun intensity? Or is it that they much too far away from the temperate latitudes that air might not be able blow down there?

I imagine sun intensity has something to do with it also.

Edited by Rick Santos, 09 January 2012 - 12:34 PM.

[Dypsisdean]

I live almost directly on the Tropic of Cancer (19.7˚N). And I can attest that cold fronts (or the associated shear lines) from northern storms do reach down here quite often - although they have generally moderated quite a bit. In addition, "cut off lows" with very cold air aloft can also take up residence in these latitudes. While I don't know for sure, I don't think these weather features ever make it as far as the equatorial regions.

[amazondk]

In fact the very tail end of cold fronts from Antarctica do make it to Manaus, 3.25 degrees south. These events are known as FRIAGEM locally. But, that being said what is the normal effect is that the daytime temperatures stay under 80 degrees F. I have seen days where the temperatures stayed around 74 F which is cold for here. The night time temperatuers still stay in the normal range though from 72 to 74 F. On the other side of the equator here in Boa Vista, Roraima cold fronts do not get there from the north. They have to go across the Caribbean and the mountains in Venezuela and Guiana and do not get that far south. As to Belem I do not know if they cold fronts get there or not as I have not paid attention to this. Belem also has some influence from the Atlantic ocean which is not that far away, as well as the estuary of the Amazon river which is an enormous area. The cold fronts that get here arrive in the hottest part of the year which is the dry season. People pull out there sweaters when the temperature stays below 80 F.

As to why is it always warm here. At 3.25 S. latitude and around 200 feet above sea level hot is the norm. The main factor that modifies temperture is rain. Now is the rainy season which is known as the Amazonian winter. Even though we are in the southern hemisphere summer. The hottest time fo the year is the dry season in the months of August, September and October.


dk