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Yeah, some coastal desert locations such as the surronding cities near the Atacama desert have a cloudy but a extremely dry climate because of the Humboldt Current, which is a cool, wet marine current that come from the South Pole where it's extremely cold and that goes along the west coast of the South America. This current is the consequence of the upwelling effect and considerably cools off and dries out the hot, tropical climate but is responsible of a much cloudier climate by forming lots of low clouds and fog, especially the camanchaca. The Atacama desert, itself, doesn't have this abundant cloud cover because the Andes Mountains and the other minor mountains ranges block the clouds and the fog along the coast. The other driest places on the world, which are essentially located in the Sahara desert (Egypt, Sudan, Libya) have an extremely low, a nearly non-existent cloud cover, with a sunshine duration between 3,700 hours and which can even go over 4,000 hours annually.
As I have taken pains to point out already, the Chilean coastal Atacama cities are cloudy compared to the interior, but not all that cloudy by global standards - even Arica in the far north has about 2400 hrs per annum, while Antofagasta is certainly sunny by global standards. More detail in an earlier post of mine.
As I have taken pains to point out already, the Chilean coastal Atacama cities are cloudy compared to the interior, but not all that cloudy by global standards - even Arica in the far north has about 2400 hrs per annum, while Antofagasta is certainly sunny by global standards. More detail in an earlier post of mine.
2,400 hours of sunshine is a very low sunshine duration for a such latitude, as the Atacama desert is located in the horse latitudes (30° and 35°), where the subtropical ridge normally prevents much of the clouds formation. It'd be good if the Atacama desert itself had a weather station that tracks the sunshine hours. I think the sunshine duration would probably be around 3,000 hours.
2,400 hours of sunshine is a very low sunshine duration for a such latitude, as the Atacama desert is located in the horse latitudes (30° and 35°), where the subtropical ridge normally prevents much of the clouds formation. It'd be good if the Atacama desert itself had a weather station that tracks the sunshine hours. I think the sunshine duration would probably be around 3,000 hours.
A University of Chile paper on solar radiation - which I quoted from in an earlier post - estimates Calama having 3,920 hours - which sounds feasible. As one poster has pointed out more than once, sunshine measurements in US sites, Chicago and perhaps of couple others aside, have virtually disappeared in recent times. Many of the claimed numbers for US sites might have more credibility if more places were still measuring.
Incidentally, at least half of the Atacama is north of 23S. Antofagasta, near this latitude, receives over 3000 hours.
A University of Chile paper on solar radiation - which I quoted from in an earlier post - estimates Calama having 3,920 hours - which sounds feasible. As one poster has pointed out more than once, sunshine measurements in US sites, Chicago and perhaps of couple others aside, have virtually disappeared in recent times. Many of the claimed numbers for US sites might have more credibility if more places were still measuring.
Incidentally, at least half of the Atacama is north of 23S. Antofagasta, near this latitude, receives over 3000 hours.
Oh, my god!! 3,926 hours of sunshine!! That's just amazing! So, it's in the top 5 sunniest places in the world? Because there are only three or four locations in the world that have a such sunshine duration, Yuma, Arizona; Marsa Alam, Egypt; Kosseir, Egypt and Redding, California have all over 3,900 sunny hours, too. But 3,926 hours seems to be a little excessive, isn't it? I still agree with you and I think it's possible but again, little likely. I'm not really sure of that, as well some surrounding cities such as San Pedro de Atacama have a much, much lower sunshine duration. And the solar radiation isn't the same thing as the sunshine duration.
Last edited by Special_Finder; 05-31-2014 at 03:29 PM..
Oh, my god!! 3,926 hours of sunshine!! That's just amazing! So, it's in the top 5 sunniest places in the world? Because there are only three or four locations in the world that have a such sunshine duration, Yuma, Arizona; Marsa Alam, Egypt; Kosseir, Egypt and Redding, California have all over 3,900 sunny hours, too. But 3,926 hours seems to be a little excessive, isn't it? I still agree with you and I think it's possible but again, little likely. I'm not really sure of that, as well some surrounding cities such as San Pedro de Atacama have a much, much lower sunshine duration. And the solar radiation isn't the same thing as the sunshine duration.
I'm not aware of any readings for San Pedro, but it is closer to the Andes. The paper the data was cited from looks pretty respectable. I think the Calama figure is probably not far off. It is far from the coast and avoids any coastal effects, but is also far enough from the Andes to average only 5.6mm rainfall annually.
The village of Quillagua, inland from Antofagasta, which over about a 40-year span had only 4 rainfall events and averaged less than 0.1mm, might well be a candidate for averages close to the 4000 mark.
I'm not aware of any readings for San Pedro, but it is closer to the Andes. The paper the data was cited from looks pretty respectable. I think the Calama figure is probably not far off. It is far from the coast and avoids any coastal effects, but is also far enough from the Andes to average only 5.6mm rainfall annually.
The village of Quillagua, inland from Antofagasta, which over about a 40-year span had only 4 rainfall events and averaged less than 0.1mm, might well be a candidate for averages close to the 4000 mark.
I think these places may have a very great sunshine duration year-round but 3,900 hours is very, very high. And Calama isn't so far from the coast and low clouds and fog aren't unfrequent in the region.
I checked many websites, and the Atacama desert doesn't have any sunshine recorder but the sunshine duration is estimated to be between 3,500 hours and 4,000 hours annually (it's not very accurate but that's the only data we currently have) and may be therefore one of the sunniest places in the world, and is nearly as sunny as some places such as a great part of the Sahara desert in Northern Africa and the Mojave and Sonoran deserts in the Southwestern United States.
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