And so fall begins
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And so fall begins
by Brillig
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Re: And so fall begins
by Irv Bromberg
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Re: And so fall begins
by Philip DeRosa
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Re: And so fall begins
by Mark J. Reed
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Re: And so fall begins
by Philip DeRosa
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Re: And so fall begins
by Brillig
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Re: And so fall begins
by MIKE OSSIPOFF
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Judging by postings subsequent to Victor's posting, the Southward Equinox doesn't particularly mark an abrupt change in temperature. Of course, as Victor himself would agree, no calendar can promise that. Based on the temperate regions' typical midrange seasonal time-lag of 38 days, or 1.25 months, and based on the very widespread perception that summer begins on June 1, and that winter begins on December 1, then Summer ends around September 27th, typically. Yes, for the end of summer, the media's un-supported assumption that the Earth's seasons begin on equinoxes and solstices isn't too far off--only about a week off. But, for the beginnng of summer, and for the beginning of winter, that assumption is _way_ off. Mike Ossipoff Victor wrote: > It never ceases to amaze me how often the first day of fall has > markedly different weather -- as in colder. Last night a cold front > blew through town, dumping large amounts of much needed rain. We also > have much cooler temperatures. Yesterday, the high temperature was > 94.3F. Today, it hasn't yet climbed out of the 60s. The traditional > start of the fall season seems to be right on the money as usual. > > Victor > Hotmail: Free, trusted and rich email service. Get it now. |
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Re: And so fall begins
by Amos Shapir
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Amos Shapir Date: Tue, 22 Sep 2009 23:45:11 +0000 From: nkklrp@... Subject: Re: And so fall begins To: CALNDR-L@... Judging by postings subsequent to Victor's posting, the Southward Equinox doesn't particularly mark an abrupt change in temperature. Of course, as Victor himself would agree, no calendar can promise that. Based on the temperate regions' typical midrange seasonal time-lag of 38 days, or 1.25 months, and based on the very widespread perception that summer begins on June 1, and that winter begins on December 1, then Summer ends around September 27th, typically. Yes, for the end of summer, the media's un-supported assumption that the Earth's seasons begin on equinoxes and solstices isn't too far off--only about a week off. But, for the beginnng of summer, and for the beginning of winter, that assumption is _way_ off. Mike Ossipoff Victor wrote: > It never ceases to amaze me how often the first day of fall has > markedly different weather -- as in colder. Last night a cold front > blew through town, dumping large amounts of much needed rain. We also > have much cooler temperatures. Yesterday, the high temperature was > 94.3F. Today, it hasn't yet climbed out of the 60s. The traditional > start of the fall season seems to be right on the money as usual. > > Victor > Hotmail: Free, trusted and rich email service. Get it now. Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! Try it! |
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Re: And so fall begins
by Tom Peters-6
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You're right: dec, not temperature, for Subjective Seasonal
by MIKE OSSIPOFF
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Calendarists, I withdraw my temperature-variation and seasonal-timelag based Subjective Seasonal, but I don't withdraw Subjective Seasonal. I will base Sujbective Seasonal on declination instead. Everyone was right who argued that temperature variation, assuming a uniform seasonal time-lag, isn't the best basis for a terrestrial seasonal calendar. Not only because of geographical variation, but because more immediate effects of declination are important too, and shouldn't be ignored. For instance, the increase in sunlight around the time when the declination has become positive where you live brings the vegetation back to life. And people of course perceive how sunny it is, and that has a lot to do with how they perceive the season. And of course the long sun-illuminated evenings in summer are an important part of what summer is. Subjective Seasonal should be based on declination, not on temperature variation. As you all have argued, declination is what is the same everywhere. This one next paragraph repeats something I said before: I was right to point out that, in a wide variety of temperate zone places, it's perceived that northern summer and southern winter arrive with June, and that northern winter and southern summer arrive with December. As I was saying before, that, by itself, defines summer and winter in that way, and how else should summer and winter be defined, other than by than what people call by those names? But the wordwide-uniform changes in solar declination could have a lot to do with explaining why, for instance, so many people in the Northern hemisphere agree that summer arrives with June, and why so many in the Southern Hemispher agree that summer arrives with December. The practical difference in this new approach to Subjective Seasonal is that its seasons will be based on the dates when those seasons are perceived, and the ends of summer & winter won't be determined by a time-lag assumption, as they were before. Subjective Seasonal will become even more subjective than before. But why not? What are the winter, spring, summer and autumn? Something that you or I define them as, by decree, because it satisfies us as "scientific"? Or what people have long meant by winter, spring, summer and autumn? In writings about the seasons, many have expressed the opinion that June is when full summer arrives. And many have pointed out that April is the beginning of spring. As I was saying, when the declination has become positive, more light for photosynthesis brings a rapid return of plant-life. And when June arrives, people are noticing how much sunnier it is and how much longet the day is. So the revised Subjective Seasonal will start the seasons at the average solar ecliptic longitudes for December 1, April 1, June 1 and October 1. Those average solar ecliptic longitudes will be determined as I did before. For the fixed version, I'll use the same leapyear system that I've been proposing: Minimum Distance. I'll post the numerical details for a new Subjective Seasonal Calendar, based on declination. I'll probably get a chance to do that within the next month, maybe within a week, I don't know. Maybe someone here will beat me to it. I hope so: Many of you have some position and prestige, and a proposal from you would be noticed more than would a proposal from me. It will be in 3 versions: Fixed, Nonfixed, and Old-Months. The Old-Months version, for which I got the idea from Karl, would just use the same months we have now, but would re-name them for the new calendar. Summer starts June 1, Autum starts October 1, Winter starts December 1, and Spring starts April 1. In all 3 versions the calendarical seasons would be named as before: South, Northward, North, and Southward. They'd bd divided into months just as before: 4 months for North & South. 2 months for Northward & Southward. The naming of the months would be the same. Though I like the simplicity of having the fixed version start each season with a long month, I understand the practical advantage of making the long month the _second_ month of North & South, to make space the long months uniformly in normal years. South will be the first calendrical season of the year. For nonfixed and old-months, leapday will be in South. For the fixed verion, leapweek will be in the last month of the year (Southward). As much as I appreciate the millennia-scale advantages of basing the leapyear system on the particular tropical-year length at June 1, it's also true that _every_ date in the year is important too, justifying the average optimization that is gotten by basing the leapyear rule on the mean tropical year. Besides, there's more familiarity with the mean tropical year. Anyone can go to a library and look up, in any encyclopedia or astronomical almanac, the mean tropical year length of 365.242190 days. That easy verification by anyone could help acceptance. And, when using 1.24219 as the assumed annual drift of the 364-day year, and designing the leapyear rule to counter that, will only give us a calendar drift of about 17 minutes in the first millennium. And a little over an hour in the first two millennia. That isn't enough to be a problem. Especially since all of us are tolerant of the cyclical displacement of a leapweek calendar. But, though I prefer 1.24219, based on the mean tropical year, I'd also accept a leapyear rule based on the particular tropical year at June 1. I believe that Karl said that, then, it's 77/62 instead of 1.24219. Just as many Northern Hemisphere authors say that June starts summer and April starts spring, contradicting our media's equal-seasons assumption, I believe that there are authors in Australia who say that September doesn't feel like spring and that October does. And I expect that many Australians would say that if asked. In whatever country you live in, what are the officially-designated dates for the beginning of winter, spring, summer and autumn? What are the perceptions about that, expressed by people you've heard on the subject? This is a relevant calendar question, and I hope that you'll give me your answers. Mike Ossipoff Insert movie times and more without leaving Hotmail®. See how. |
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Re: You're right: dec, not temperature, for Subjective Seasonal
by Brillig
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Re: You're right: dec, not temperature, for Subjective Seasonal
by Tom Peters-6
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Re: You're right: dec, not temperature, for Subjective Seasonal
by MIKE OSSIPOFF
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Calendarists, Thanks for the answers to my question about perceived and official seasons. I look forward to hearing more. There's much agreement between the seasons described by Victor and Tom. Also, temperature-wise, (Northern Hemisphere) winter and summer seem to end around the times that they described. Here's what made me re-consider Subjective Seasonal: It occured to me that it wasn't accurate enough for me to measure some time-lags from solstice to temperature min or max, and then use a global average of that everywhere, for all times of year. Better, I decided, to just go directly by local temperature records, not lag: I define "thermal end of winter" as the day whose mean temperature (I prefer to use mean daytime high) is the same as that of the first day of winter. Likewise for summer. It seems widely agreed that June is the 1st summer month and December is the 1st winter month in the north, and vice-versa in the south. I know that nothing is uniform everywhere, but, for an international calendar, one looks for what is typical or average. When I started looking at thermal end of summer and winter, I noticed that it tends to occur earlier than the average lag had led me to expect. Authors in England have had a lot to say about April being the first really fullly spring month, with March being rather on the blustery side. That's been my impression too: Sure there are some genuine spring days in March, but they seem more of a preview of spring, while my overall impression of March in California has been that it feels like the tail-end of winter. But, among the U.K. locations that I've found temperature records for, in the TimesBooks World Weather Guide, and a paperback weather guide for travel, not even one of those U.K. cities listed has its thermal end of winter as late as April. In fact, the mean date is March 6, with an extreme early date of Feb 1. Maybe we have a different standard for how much weather-niceness we want to call "spring", as compared to how harsh it has to get before we call it "winter". Maybe what that has in common is that it has to change a lot in a particular direction before we declare a change of season. Also, the re-awakening vegetation, having a lot to do with solar declination, may be a factor favoring April as spring. But of course it couldn't be only declination either. If summer and winter were defined as periods with solar-declination-magnitude over a certain value, then, of course summer and winter, if they start with June & December, at quite high declination-magnitudes, they'd be quite short, only about a month or so long. That isn't what anyone perceives. So I expect that it's a mix of temperature and sunlight, and also that the beginning and end of summer & winter aren't necessarily perceived symmetrically as times of temperature or light being equal. One thing, of course--For an international calendar, calendrical Southward should start 6 months after the start of calendrical Northward, if spring is felt to arrive with similar declination-magnitude north and south of the equator. That bit of symmerty would have to be imposed on the calendar as an international compromise. Because there are some spring days in March, sure there's a case for naming March a spring month. And thermal end of summer & of winter tends to agree with the Victor's & Tom's mention of March & September as spring and Autumn. Some authors have defined an additonal season, "early spring", which could also be called "pre-spring", and its starting times, according to various different authors, seems to agree roughly with the thermal end of winter. September, like March, might qualify for double-status too. In Santa Cruz, September feels very summer-like, but not everyone everywhere says that. Of course Santa Cruz tends to get fogged-in, in July & August, with its maximum summer tending to fog itself out--and that emphasizes September's beach-warmth, without anything warmer to compare it to. So it isn't entirely obvious or unanimous which season March and September should go with. Maybe winter and summer should be followed by a brief pre-spring and pre-Autumn. Or maybe that would be too much of a complication, adding more calendrical seasons. Mike Ossipoff Hotmail: Trusted email with Microsoft’s powerful SPAM protection. Sign up now. |
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Re: You're right: dec, not temperature, for Subjective Seasonal
by MIKE OSSIPOFF
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Tom-- Thanks, in advance, for the interesting idea of the daily almanac of the solar year, and for the local seasonal separation comments. I look forward to those comments being posted, because of course that's an interest of mine. A few brief comments: > This ongoing discussion assumes that there have to be 4 seasons. Some authors name 6 or more. Now I'm suggesting that (probably) Subjective Seasonal should have 6 calendrical seasons. Of > course in many parts of the world only 2 or 3 can be discerned (e.g. > a dry and a wet season). Yes, but, no matter where you are, there are long periods of high north and south declination, and briefer transitional periods. Sure, they have different effects in the tropics, where it's rainiest when the sun is near the equator. > Furthermore, subjectively they will not have the same length and have > the same start- and end-dates all over the temperate zone. Yes, but many seem to define Dec 1 & June 1 as season-beginnings. Opinion is divided on which season September & March go with, which is why I suggest giving those months their own "season". By the way, the earliest therman end of summer I found in the U.K. was Feb 21, not Feb 1. The average was March 5, not March 6. The latest was March 20--for a 27-day variation-span. Mike Ossipoff Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up now. |
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