Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Actually the BOM appears to use Köppen's temperature thresholds exactly for its subtropical climates ie climates that are cooler than 18C in the coolest month and warmer than 22C in the warmest month. The only difference is that given Australia's much lesser continentality, any climate that satisfies the requirement for >22C is also going to have warm winters. Or to put it the other way round, anywhere with cool winters is also going to have cool summers.
It's the same in South Africa - East London is around the limit of >22C warmest months, at Köppen's Cfa/Cfb border.
Then those work for places that are subtropical in Australia and South Africa under the Koppen climate classification. Just not as the only subtropical climates in the world, or as the only possible options weather wise for a subtropical climate.
Quote:
Originally Posted by Bisfbath
The BOM aren't just "some Australians", they maintain some of the best climate and weather records in the world, and even if they were it isn't clear why their opinions would be less important than "some" of anyone else.
That may be an appeal to authority. Regardless of how good records they keep, if their opinion makes no logical sense, it's just an opinion.
Of course, I now realize they could just be referring to the mentioned areas in Australia and South Africa that are subtropical without disregarding other subtropical areas in the world like the US, in which case it makes perfect sinse. But if they aren't, then their opinions make no sense.
Then those work for places that are subtropical in Australia and South Africa under the Koppen climate classification. Just not as the only subtropical climates in the world, or as the only possible options weather wise for a subtropical climate.
That may be an appeal to authority. Regardless of how good records they keep, if their opinion makes no logical sense, it's just an opinion.
Of course, I now realize they could just be referring to the mentioned areas in Australia and South Africa that are subtropical without disregarding other subtropical areas in the world like the US, in which case it makes perfect sinse. But if they aren't, then their opinions make no sense.
Grassisgray also hit the nail on the head IMO.
Bingo - I think you got it. The BOM says nothing about "NH type" Cfa climates because they don't exist in Australia. So there's no reason to think they don't consider them subtropical or have any special claim on subtropicality. To claim any particular region has "true" subtropical climates is the kind of nationalist nonsense that science tries to avoid. The SE USA doesn't have an "inferior" or "not true" subtropical climate and neither does Australia. They're simply different.
Koppen's C*a category is so broad it's not really useful on world scale. With a coolest month of between 0C and 18C it contains radically different climates. Even the poleward edge of Cfa climates are radically different depending on what they transition into eg East London is at the poleward margin of Cfa climates in Southern Africa where the warmest month ceases to reach 22C and the native vegetation is evergreen thickets or forest with year round growth and ecological activity and can even grow coconut palms. On the other hand in New York where the limitation is getting close to the coolest month being 0C, the warmest month still easily reaches 22C and native vegetation is deciduous forests with heavy winter dormancy/little ecological activity. They are useful when talking of a particular region eg eastern Australia, the S/SE USA, S/SE China etc. But not so much for comparing the S/SE USA with eastern Australia etc.
Appeal to authority is only a logical fallacy where the authority has no obvious qualification in the field. So the BOM's authority in the climates of Australia is legitimate as it's probably the most qualified organization on the climates of Australia. It would only be a logical fallacy if it was using its authority on some subject it had no expertise in, say heart surgery or cake baking.
I think Koppen's C*a climate is useful on a world scale as long as you acknowledge that it will give different results for each hemisphere because of different geography. As the deleted comment said, the different hemispheres shouldn't be compared because they're too different to make any meaningful comparison (which is also consistent with what you said, such as about comparing the US to Australia).
And just to clarify the definition of appeal to authority, even though it's clear the BOM's case is not it. It's saying that because it's the opinion of an expert it's right, which is not always the case. https://en.wikipedia.org/wiki/Argume...0an%20argument.
Any Charlotte residents want to defend their subtropical climate?
Nashville?
Bonus pic:
Winter in Florida
Coldest weekend in a decade they're saying. Some palms are having a tough time of it.
The earlier forecast charts for the mid or upper south locations are why "subtropical" needs to be redefined, and such places in the charts called warm temperate, or something better that describes "variable mid-latitude to southern winters, southern summers".
The last photo is not what one would expect a few hundred miles from what Koppen adherents claim is the northern part of the tropics or well within the tropics, Miami to Fort Pierce.
I mean, I agree that some maps have subtropical climates go too far north, especially ones that base the definition based on -3°C rather than freezing so include it as far north ad New York City or even Southern Massachusetts sometimes, but if a place is subtropical according to both the Köppen and Trewartha classifications (which most of the deep south, including where I live, is) than it is DEFINITELY subtropical
(Köppen overall is still superior to Trewartha but Trewartha has a better temperature definition for subtropical than Köppen)
True, though I might not even consider a coldest month mean of 0c "subtropical" but a "warm temperate" climate. With some warmer figure for the coldest month mean as subtropical.
Koppen didn't get the issues with using -3c for the coldest month mean in the humid eastern climates (C subtropical to D temperate) any better than he did by flipping to 18c for the annual mean in the dry western climates (BWh & BSh hot or subtropical to BWk & BSk cold or temperate). No consistency.
True, though I might not even consider a coldest month mean of 0c "subtropical" but a "warm temperate" climate. With some warmer figure for the coldest month mean as subtropical.
Koppen didn't get the issues with using -3c for the coldest month mean in the humid eastern climates (C subtropical to D temperate) any better than he did by flipping to 18c for the annual mean in the dry western climates (BWh & BSh hot or subtropical to BWk & BSk cold or temperate). No consistency.
You're right ...no consistency.
Koppen flipped to 18C annual mean temperature as his line in the sand (no pun intended)
for the dividing line between hot desert (subtropical) and cold desert (temperate)...
For example...you live in Las Cruces, New Mexico...which has a 17C annual mean temperature...
so by Koppen ....just missing the mark for being hot desert....I'm not sure why 18C
threshold was chosen...imo a bit high .....15C or maybe 16C would be better.
For drier BWk / BWh and BSk / BSh climates,
Koppen also set a 6C mean temperature in the coldest month threshold too
...so ...18C average annual mean or higher and coldest month average mean 6C or higher
to be BWh or BSh. Which places like Phoenix and Tucson easily surpass.
Not sure why he didn't set the same thresholds for Cfa thresholds....
then only the "Deep South" would be considered to be subtropical.
Koppen flipped to 18C annual mean temperature as his line in the sand (no pun intended)
for the dividing line between hot desert (subtropical) and cold desert (temperate)...
For example...you live in Las Cruces, New Mexico...which has a 17C annual mean temperature...
so by Koppen ....just missing the mark for being hot desert....I'm not sure why 18C
threshold was chosen...imo a bit high .....15C or maybe 16C would be better.
For drier BWk / BWh and BSk / BSh climates,
Koppen also set a 6C mean temperature in the coldest month threshold too
...so ...18C average annual mean or higher and coldest month average mean 6C or higher
to be BWh or BSh. Which places like Phoenix and Tucson easily surpass.
Not sure why he didn't set the same thresholds for Cfa thresholds....
then only the "Deep South" would be considered to be subtropical.
There isn't any reason other than simplification to use the same thresholds for different categories though. Koppen was trying to link climate and environment, and there's no particular reason why the same temperature thresholds should apply to different environments.
There isn't any reason other than simplification to use the same thresholds for different categories though. Koppen was trying to link climate and environment, and there's no particular reason why the same temperature thresholds should apply to different environments.
+1. I'd also add Koppen considers 0 Celsius in the coldest month as another possible isotherm between hot and cold arid climates.
I'm growing Canaan Fir trees very successfully in southern Indiana at just under 900 ft. elevation. The lowest temperatures in the winter can range from 5F to -25F depending on the weather pattern. Good luck trying to pin down a plant hardiness zone for this area.
The earlier forecast charts for the mid or upper south locations are why "subtropical" needs to be redefined, and such places in the charts called warm temperate, or something better that describes "variable mid-latitude to southern winters, southern summers".
The last photo is not what one would expect a few hundred miles from what Koppen adherents claim is the northern part of the tropics or well within the tropics, Miami to Fort Pierce.
How are winter forecasts ranging from highs of 32 - 60 F not subtropical? That's squarely subtropical.
Miami is objectively tropical in climate and ecology.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
