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See above. Basically the purpose is to find out what tropical climates that tropical component of subtropical is comparable to: borderline ones, quintessential ones, etc.
If this is confusing I'll leave it to Memph to explain, that's the best explanation I can give.
I go to college in Worcester Massachusetts and definitely feel as if I'm in a different climate. The vegetation in Massachusetts is pretty different with many birches and aspens and just overall smaller trees than in DC. Plus Massachusetts does have long periods of snow and ice cover (even if the snow may be patchy) whereas DC has bare ground for most of the winter as well as open lakes with little or usually no ice.
Maybe the trees in Massachusetts were logged more recently? The canopy layer in tropical rainforests is not that much different from the height of the canopy layer in southern Ontario it seems.
The tallest tree in Ontario, near Ottawa, is a 156ft tall white pine. 60-80ft is canopy layer, more or less, and 80-110ft trees are typically emergent, but not that rare, in areas with 50+ year old trees.
The tallest white pine in Ontario is 147ft.
In DC I suspect the canopy and emergent layers are similar to tropical forests, oceanic climates like the PNW and subtropical climates often produce forest canopies as taller or taller than in the tropical rainforests.
I'm surprised you see so many birches and aspens in Worcester. Birches reach their peak density here in Ontario around places like Red Lake, which is very much colder than Worcester.
However, as you approach Sault Ste Marie, you enter the "mixed wood forest" with beech, maple, white pine and hemlock present in greater quantities and beginning to displace the larch, spruce/tamarack and birch. https://www.google.ca/maps/@46.82868...7i16384!8i8192
Around the east end of Algonquin Park, Huntsville, Muskokas, the deciduous forests start to dominate. However, the deciduous forests are still predominantly maple, beech, and some oak. https://www.google.ca/maps/@45.28247...7i13312!8i6656
Here's a patch of forest near Toronto that looks straight out of the Hudsons Bay lowlands. Which shows that at least some of this comes down to soil (boggy, rocky soil = a more "boreal" mix?): https://www.google.ca/maps/@43.99327...7i16384!8i8192
Fairly typical deciduous forest with lots of maples around Hamilton. White Pine can generally co-exist in deciduous forests (at least to some extent) because they can easily exceed 80ft and grow very quickly. https://www.google.ca/maps/@43.24025...7i16384!8i8192
By Point Pelee, the trees seem taller, I'd say 75-90ft canopy compared to 60-80ft for most of Southern Ontario. https://www.google.ca/maps/@41.98115...7i13312!8i6656
And much more diversity of deciduous trees (this is true of many areas south of Brantford though). Basswood, tulip tree, sycamore, cottonwood, black walnut, mulberry, redbud, hickory, honey locust, kentucky coffee, hackberry, sassafras, blue ash, in addition to many varieties of maple and oak.
You're the same person who said palm trees can't grow anywhere averaging below 50F lol?
That trewartha map goes all into Tennessee and Arkansas, places that aren't exactly palmy.
Yeah that's one problem with Trewartha's system- as Geodiode said it doesn't really consider human perception of comfort. Which is apparently why he used the 10 C in the coldest month to distinguish between "cool" and "mild" variants of C_b and C_a. I am of the opinion that subtropical climates fundamentally do not have "cool/chilly" winters, and I would extend this analysis to Cs_ climates to distinguish "truly subtropical/classic Mediterrarnean" Cs_ climates from "marine west coast" types like what we have in the Pacific Northwest.
In my view the prototypical tropical climate has a mean temperature of 26-29C year round.
The climates that have their coldest months around the 18C cut-off are transitional in some way or another, whether it's transitional towards subtropical with continental influences (ex Kaohsiung, Naples FL) or transitional towards tropical highland climates (ex Butembo, Bukavu, Mount Hagen, Merida VNZ) or transitional towards subtropical-oceanic (ex Rapa Iti, Easter Island).
And in many cases, 18C is just the coolest month. The annual mean can be a fair bit warmer, in Florida and Taiwan the tropical-subtropical boundary has annual means of around 24-25C.
So if a subtropical climate has a mean for the 6 warmest months that's comparable to the annual mean for a subtropical-tropical transitional climate, then that suggests they might be subtropical transitional towards something cooler. That goes for the Upland South, Ohio Valley, Mid-Atlantic, Piedmont... Charlotte, OKC, Nashville, they are like "subtropical-lite" to me, I would still consider them subtropical, but the prototypical US subtropical climates would be Savannah, New Orleans, Houston, Tallahassee and the like.
Agree with this (with the caveat that tropical locations at sea level usually have mean temperatures of 26-29 C, places at even marginally higher elevations are going to cooler than that). Most of the Southern US not near the Gulf Coast is "subtropical-lite" or "transitional subtropical" at best.
BTW. I'm taking a look at the trees native to Nashville. It does have some trees that could be described as subtropical, which are not native to the southern Great Lakes. However, it seems like the southern Great Lakes ("warm continental") and even the hemiboreal zone are more important transitions in terms of running into new species.
Some examples of these subtropical trees are: river birch, American persimmon, sweetgum, southern red oak, willow oak, shumard oak and post oak.
I am of the opinion that subtropical climates fundamentally do not have "cool/chilly" winters
How many times do I have to ask this, what is so unreasonable for a SUBtropical climate to have cool weather? It's not tropical, there needs to be something definitely not tropical about it.
Do you want to argue as mentioned that Yakutsk isn't subarctic because of its warm summers? That is the converse of arguing subtropical climates do not have cool winters.
No subtropical climate has a chilly winter though, I'll give you that. That would require a 0 Celsius or below average temperature, whereas subtropical climates must be above 0 Celsius.
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Originally Posted by psyche_da_mike24
and I would extend this analysis to Cs_ climates to distinguish "truly subtropical/classic Mediterrarnean" Cs_ climates from "marine west coast" types like what we have in the Pacific Northwest.
Aside from the reasons for your split not working that I listed, Cs climates technically aren't subtropical - not enough summer precipitation even though they can easily be hot enough. This is the same reason why places like Niamey and Honolulu are not tropical.
Still can't access your video, sorry.
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Originally Posted by psyche_da_mike24
Most of the Southern US not near the Gulf Coast is "subtropical-lite" or "transitional subtropical" at best.
This definition doesn't work, how many times do I have to explain that. Most of the Southern US not near the Gulf Coast is either within the coolest 1/3 of subtropical (which subtropical-lite is really only good as a description for, it's just a way to convey it's the coolest 1/3, not its own classification) or middle ground (in the middle of 0-18 Celsius) subtropical climates between 6-12 Celsius.
I think you may need to come to terms more with the nature of a borderline climate resembling the climate it borders on more than the core of the climate type it actually is.
Last edited by Can't think of username; 12-12-2022 at 05:54 AM..
I like the idea of making the subtropical designation based on % of the year where the climate resembles the tropics. Ideally that period would be around 6 months, as mentioned upthread. I think anywhere from 4-8 months is a fair range
I don't think we should use 4 or 6 month averages, which favours continental climates with a hot short summer. I don't think we should give infrequent cold snaps more credit than due either. The best approach I think is to use daily actuals and average those over a period of years.
How many individual days per year does the weather feel like an average day in the tropics? The trouble is determining that treshold. To me I think either a low of 18+ or daily average like 25+ is good enough. depending where you set the threshold will make a difference.
Using my home climate of Atlanta as a very typical US subtropical climate, going to check how it stands up to this critera:
The first day of the year (1/1/2022) actually met the tropical threshold, with the (low, avg, max) of (20, 22.3, 26). This was unusual though, and two days later the reading was down to (0, 3.2, 9).Quite the difference. A few warm days came close in between, but the threshold was not met again until mid April.
Assuming no more this year we get: 142 days of tropical weather or 39% of the year. For 2021 it was 145/40% and for 2020 it was 138/38%
I think the most important thing is deciding what is the cutoff for a 'tropical weather' day. Is 18+ low or 25+ average fair? if we have an objective cutoff it would be easy to run a program on many stations and years at once instead of just skimming WU history
I would say the 4 month criteria at least works. It seems to be in line with the 4 months above 10 Celsius subtropical climates must also have, and is also where borderlines like New York make the cutoff around, in terms of both averages and number of actual days with the average.
IMHO, anything with a daily average of 18+ Celsius is fair game. Considering that these are subtropical climates which are going to be always transitioning to non tropical weather some of the year, the bar should be there for them.
I don't know if this or memph's should be a designation, by the way, even though they seem to work for all US subtropical climates. I'm open to adding it as one because it wouldn't change any other US criteria, though.
I would say the 4 month criteria at least works. It seems to be in line with the 4 months above 10 Celsius subtropical climates must also have, and is also where borderlines like New York make the cutoff around, in terms of both averages and number of actual days with the average.
IMHO, anything with a daily average of 18+ Celsius is fair game. Considering that these are subtropical climates which are going to be always transitioning to non tropical weather some of the year, the bar should be there for them.
I don't know if this or memph's should be a designation, by the way, even though they seem to work for all US subtropical climates. I'm open to adding it as one because it wouldn't change any other US criteria, though.
I think 4 months 18 avg is too lenient though. I picked that number as the low end because it was the average January low for Havana. Using Havanna since it is very close to the edge of the tropics and has cooler winters than equatorial places, which would have average lows 23+ all year and be nearly impossible for subtropical places to reach that benchmark.
BTW even tropical places can have days that don't feel tropical. Especially near the edges of the tropics like Havanna or tropical climates outside of the tropics in Florida. 4-8 months is subtropical 8+ is tropical
we had days here recently with lows of 12-14 and highs 22-26 that would have made the tropical cutoff based on an 18 avg. While that is quite pleasant comfortable weather it certainly didn't feel tropical stepping outside at 7am
I kind of agree with much of that. But what does your system offer over and above the Koppen requirement of needing a month above 22°C?
Depends if you want a classification system that matches up with vegetation vs just a certain set of temperatures. I agree having 28-30C warmest months vs 20-24C warmest months makes little difference for vegetation, but it will still make an impression on the people experiencing the climate.
I think experiencing very hot summers can be an alternative way for a climate to be subtropical. For oceanic/maritime climates, it's more about having cold-intolerant species and a lack of a dormant vegetative season (or at least, a dormant season that is temperature controlled).
For more continental/non-maritime climates, long, hot summers can be an alternative way to achieve a different kind of subtropical climate.
I personally prefer using a mean temp of around 13-14C though, and then splitting that zone into hot summer continental-subtropical and mild winter oceanic-subtropical. So that list focused on the hot summer component, but I think the mild winter component should also be considered.
I think 4 months 18 avg is too lenient though. I picked that number as the low end because it was the average January low for Havana. Using Havanna since it is very close to the edge of the tropics and has cooler winters than equatorial places, which would have average lows 23+ all year and be nearly impossible for subtropical places to reach that benchmark.
I would not advise that because it does not deal with the full range of tropical climates (as you said the cutoff is Havana) like it is supposed to with subtropical climates. If we are to apply it to all subtropical climates, it must be applied to all tropical climates, and that includes those all the way up to the 18 Celsius average border, alleviating any leniency.
However 4+ months of 18 Celsius lows seems to be the case starting roughly around or close to quintessential subtropical climates, give or take. Macon and Atlanta and Wilmington are around where it starts.
That's what might be expected - it seems to be similarly restrictive to only using Havana south.
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BTW even tropical places can have days that don't feel tropical. Especially near the edges of the tropics like Havanna or tropical climates outside of the tropics in Florida. 4-8 months is subtropical 8+ is tropical
Indeed they can!
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we had days here recently with lows of 12-14 and highs 22-26 that would have made the tropical cutoff based on an 18 avg. While that is quite pleasant comfortable weather it certainly didn't feel tropical stepping outside at 7am
I think what you mean is that it didn't feel equatorial, it would absolutely feel tropical in the sense of the winter weather of places like Fort Myers.
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. Most of the Southern US not near the Gulf Coast is either within the coolest 1/3 of subtropical (which subtropical-lite is really only good as a description for, it's just a way to convey it's the coolest 1/3, not its own classification
