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Location: The western periphery of Terra Australis
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This is something I've been wondering about for awhile now. Why are winters in most of our Outback comparatively chilly compared to similar places in the Northern Hemisphere? Broome, at the latitude of Bangkok, has almost got frost before (and places inland from Broome at low latitude have), and Rockhampton has winter nights a good 5C colder than Hong Kong, which is considered cold for it's latitude (Rocky is also about the latitude of the Tropic of Capricorn, while Hong Kong is just south of Cancer). I saw a map of the 20C isotherm in the winter month and it is well above the tropic of Capricorn over the interior of Oz, while it's even a bit closer to the equator in the Sahara, the coldest of the northern hemispheric areas.
I think the reason is the landmass of Australia is centered closer to the equator than many of these northern hemisphere countries at a similar latitude, and the associated high pressure cells are pretty strong during the winter. While Florida or even Halong bay or Hainan are constantly swept by warm seas, the interior of Australia doesn't get much oceanic influence at all. Alot of the Outback is also a good 400m+ asl, although it seems the lower parts of Queensland get just as cold. For the same reason, southern Australia is mild for it's latitude in the winter months.
Oz is also more continental in a way than South America or Africa at the same latitude because it is much wider, and the predominating winds tend to blow either from the east or the west (dry tradewinds blow in a generally NE direction in the sub-tropics, following the anticyclonic anticlockwise direction in the Southern Hemisphere). So the thermal core of Australia if you like is centered around 19-20'S, leading to particularly hot summers and 'cold' winters in these regions.
The explanation you gave sounds like a pretty good one. I also think the fact that Australia is so dry also plays a part as there is a lot of heat lost at night once the sun goes down. Land heats up and cools down faster than the sea and since Australia has a large land area in the subtropics, it would make sense that nights can get pretty cold as there is no moderating influence of an ocean in the outback of Oz. I could be wrong but that's what I always thought.
I remember reading about Alice Springs having a high of 6C last southern winter which seemed pretty shocking to me for its latitude, but I don't know how rare that is for them and if there's anywhere else at a comparable latitude which could get that.
Location: The western periphery of Terra Australis
24,544 posts, read 56,029,399 times
Reputation: 11862
Quote:
Originally Posted by ben86
I remember reading about Alice Springs having a high of 6C last southern winter which seemed pretty shocking to me for its latitude, but I don't know how rare that is for them and if there's anywhere else at a comparable latitude which could get that.
That's probably a record for the Alice, which is about 700 metres above sea-level on the Tropic of Capricorn, 23 1/3 degrees south of the equator and about 1000 km from Darwin. It's got as cold as -7C there, and the average July minimum is 3C. Daytime highs still average close to 20C though, although grey chilly spells more reminiscent of the southern states occasionally push as far north as Tennant Creek.
Your explanation sounds reasonable. I remember looking at averages at Alice Springs and thinking it was due to the dry conditions and radiational cooling at night. Can you imagine how cold it would get if the Aus continent extended to Antartica.
Choosing between Alice's sunny dry winters and wet, often cloudy conditions in our maritime piece of paradise is a no-brainer for me. As long as the days usually warm up quickly, I don't care about the night minima at all.
There'd be continental climates to the extreme there with incredible temperature swings.
Perhaps it'd be like the climate of the Canadian prairies, Siberia or Mongolia on steroids, in the southern high latitudes.
Might be a really exotic-looking hypothetical place in terms of landscape, vegetation and geography if it could exist.
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