Talk:Sunshine duration

Sunshine map 2

The map shows that northern canada and greenland get more/equal sunshine than southern canada and the north of the US. That's counterintuitive for laypeople like me, who would assume that at those latitudes you would get very low exposition. It would be nice if the article could explain why (perhaps something to do with the earth's axis inclination?), as it contains quite a detailed discussion of the map. — Preceding unsigned comment added by 139.47.115.123 (talk) 16:59, 27 April 2020 (UTC)

Sunshine map

Antarctica should be greyed out rather than labelled <1200 hours. That may be true where the continent meets the Southern Ocean, but the South Pole has a decent 2600 hours annually. Vostok at 3700 is easily one of the sunniest places on earth. — Preceding unsigned comment added by 86.22.231.221 (talk) 22:25, 13 October 2019 (UTC) This issue is clarified in the text. Regards.--186.59.141.33 (talk) 02:12, 11 April 2020 (UTC)

Should there be a table listing sunshine duration for selected locations?

I think the table that shows sunshine duration for selected locations should be deleted for a couple of reasons.

1. This article is mainly about the concept of sunshine duration. The tables do not really add much since other articles such as temperature, precipitation and wind do not include statistics for selected locations. As well, the tables can go on forever, which makes the article too large
2. More importantly, they are not comparable across countries. It would be inaccurate to compare sunshine duration of places in one country to other places in another country owing to different instrumentation. For example, sunshine data in USA are often inflated by 200–300 hours since they use the Foster photoelectric switch rather than the Campbell Stokes recorder[1](pg 23), in which the Foster one records more sunshine [2] (pg 255). As well, the USA factors in a correction factor of adding in about 1 hour of sunshine per day to account for weak sunshine at sunrise and sunset Journal of Meteorology, Vol 4, No. 4. This means one cannot compared USA sunshine values to other countries. Ssbbplayer (talk) 19:14, 13 December 2015 (UTC)

I largely agree. The world map accompanied by a thorough description in the text should suffice to describe the geographic distribution of the phenomenon. I'd rather merge that information into individual city articles than delete it outright, but that's a lot of job. Let's wait if anyone else provides an opinion, I'll leave a notice at WT:METEO. I did not know about that discrepancy due to different instrumentation – thanks. Would you please add that to the article? No such user (talk) 09:27, 15 December 2015 (UTC)

I pretty much feel the same as No such user above; the correct place for the information is in the city articles, and indeed {{weather box}} has a functionality for that. So long as the information is merged into the respective city articles that don't already have sunshine data (we would also need to find a source for it...maybe HKO or NOAA) I have no problem with it being deleted from this article. Ks0stm ^{(T•C•G•E)} 15:33, 15 December 2015 (UTC)

I had long suspected the discrepancy when comparing sunshine data of US cities such as Seattle and Vancouver or Toronto and Buffalo though I could not find the sources until now. I am pretty busy but I will try to put it as soon as possible. Regarding the sunshine data, if possible, NOAA would be the better sunshine source as HKO only provides daily values; not every country provides sunshine values as the daily format based on looking at UN Data which is the official WMO normals. Ssbbplayer (talk) 01:16, 16 December 2015 (UTC)

• I would tend to err more on the side of more information in an article like this rather than less information, but I can see the points raised above in favor of deleting/merging the current table data that's in the article right now. A particular location's average amount of sunshine will obviously vary by both the latitude & elevation (particularly by the terrain located both East & West of the site that would block a number of minutes of sunshine both after & before sunrise or sunset) of the site and the amount of cloud cover that it normally gets.

As for the measurement of this data by the National Weather Service in the USA, I used to take these kind of readings at several locations in the Northeast USA, and, while it was true that the instrumentation that we were using at the time (I forget the manufacturer's name) did not detect actual incoming sunlight at around sunrise and sunset, it usually only amounted to (well?) less than 1 hour/day in duration. We only occasionally "added" in some more minutes to the total amount of daily sunshine when we were really sure that there were absolutely zero clouds (not terrain) interfering with the incoming sunshine for the entire day (or maybe just around-about sunrise and/or sunset). If I remember correctly, a lot of that data was "lost" when ASOS was deployed nationwide in the 1990s, due to most (if not all) of those automated systems not having a sunshine meter attached to them. Guy1890 (talk) 03:04, 16 December 2015 (UTC)

It was really good to indicate how NWS recorded their sunshine from someone who worked there to ensure that my claims were right or wrong. I wonder if you mean that you added in more minutes to the total amount of daily sunshine, does this occur more frequently in the sunnier months? Ssbbplayer (talk) 05:06, 16 December 2015 (UTC)

To be clear, I can't say definitely at this point (just from my memory) that it was official National Weather Service (NWS) policy to "add" more minutes to the total daily sunshine amounts, but there may have been some mention of doing this in some of the official surface weather observation manuals (FMH-1, etc.) of the time. In general, a weather observer was always expected to use their best judgment when taking weather readings, regardless of what a particular instrument indicated.

As an example, let's say that you're working during the daylight or evening hours of yesterday (Tuesday), and you note that there hasn't been a cloud in the sky all day long...and the sunshine meter says that it's recorded 400 minutes of total sunshine for Tuesday. There are tables available that indicate the total amount of available daily minutes of incoming sunshine for each surface observing location (based, I think, just on a station's latitude & assuming that the surface observation location was at sea level), and let's say that those tables say that Tuesday's maximum potential sunshine was 423 minutes (I'm just making these numbers up BTW). It would be fine for the observer to change the official tally for total minutes of daily sunshine to 423 minutes (or 100% of available sunshine).

As another example, let's say that one is working at a location where a range of mountains to the West of a surface observing station routinely blocked the last 10-15 minutes of available sunshine on any given day (due to the Sun "falling" below the tops of those mountains). We used to record something called the "Character of Sunrise" and "Character of Sunset" (Clear, Cloudy, Foggy, Hazy, Smoky, etc.), which basically meant was anything obscuring the view of the Sun as it rose or fell below the horizon? In this hypothetical example, if the "Character of Sunset" was Clear, then one could easily just add in those extra minutes to whatever the sunshine minute total that the sunshine meter displayed. There was an option for a human weather observer to add in these "Character of Sunrise" and "Character of Sunset" indications onto an ASOS daily summary, but I doubt that many of the relatively few surface weather observation stations that still have human observers "backing up" ASOS readings do this anymore.

To be honest (and again this is just based on my memory alone), I don't remember that the above kind of corrections happened over a large number of days per year and not necessarily always during the normally sunnier months. One can get a totally clear (and usually very cold) day in the wintertime in the Northern Hemisphere. Guy1890 (talk) 06:44, 16 December 2015 (UTC)

It does show an excellent example of how sunshine duration is not measured in the same way around the world, lending support to remove the table as they are not comparable between countries. It is very useful in how some areas may have underestimated amounts due to obscurity. Thanks for providing more in depth info on how the NWS measures sunshine data; I had trouble finding it. Ssbbplayer (talk) 20:51, 19 December 2015 (UTC)

Removed

Sorry folks, but this went out of control. In hindsight, I regret even letting go the creation of "selected places" location, because Wikipedians have proven pretty bad "selecting" a representative set of data. Wikipedia is not an indiscriminate collection of information, and this article violated this. This is supposed to be an encyclopedic article, not the world's most comprehensive database about sunshine duration of every location in the world. I've just removed 200 kB of data on just about every city out there, which really ought to go to individual cities' "Climate" sections. No such user (talk) 21:31, 13 February 2016 (UTC)

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Antarctica incorrect

https://www.qudswiki.org/?query=Vostok_Station#Climate

According to this information, Vostok Station (and presumably other parts of Antarctica) receive plenty of sunshine throughout the year, at least 2,000 hours per year. The map included in this article does not reflect this fact. Is there a reason for this? Excluding this error, the map serves its purpose fairly well and should remain in the article. 67.169.243.110 (talk) 16:59, 22 April 2018 (UTC)

Map

Annual sunshine hours map of the world. Note that the data for Antarctica is accurate only for the coast. Parts of the interior receive more than 3600 hours of annual sunshine.

< 1200 h   1200–1600 h   1600–2000 h   2000–2400 h

2400–3000 h   3000–3600 h   3600–4000 h   > 4000 h

@Uness232: Would you please elaborate on inaccuracies beyond what I could personally consider minor? The "colorful" map was removed in 2021 by Average Portuguese Joe [3] with the rationale that "areas such as Antarctica, the Iberian Peninsula, west Madagascar were completely wrong", and replaced it with much worse File:Globalcldfr amo 200207-201504 lrg.jpg. Acknowledging Antarctica, I fail to see what's so horribly wrong with Iberian peninsula and Madagascar, which are minor specks in the map. I hate to see an article with no map at all, if the available ones are reasonable enough. YMMV, of course, but I personally consider those (not well explained) inaccuracies "minor". No such user (talk) 11:10, 7 August 2023 (UTC) No such user (talk) 11:10, 7 August 2023 (UTC)

I guess a quick explanation of this would be that some maps have resolutions so large and data points so scarce, that they mislead rather than inform. This map, for example, has an incredibly small set of data points (or worse, see last paragraph).

I'm not as proficient in Spanish climates but a similar case, Turkey: How much sunshine, looking at this map, does the northern half of Turkey recieve? One might assume that there are stations that have lower sunshine values than 2400 hours, and perhaps (charitably) claim that on average it might be around 2400 hours. Yet no part of northern Turkey has more than 2400 hours of sunshine. Istanbul (the largest city) and Bursa are around 2000, Trabzon 1500, Bolu 1800, Ankara (the capital) 2300. There are, of course sunnier parts of Turkey that would be in this zone, but most of Turkey would not be in it. So what was the data point for Turkey? Likely that the answer is none. The data has been extrapolated so much it has become unusable.

To add insult to injury, there are places in which small details have been kept, such as the US West Coast. There is a pocket of lower sunshine along the coast, and this has been shown, unlike a larger strip of land in Turkey, for example. And to make matters even worse, the sunshine values it claims for the West Coast are just wrong. San Francisco gets almost 3000 hours of sunshine, and so does Los Angeles. While these are somewhat lower than the interior, they should not be in the 2000-2400 category.

I hope that clears things up; the map was either manually created (very inaccurately) or was simply a victim of 20-30 data points for the entire world. Uness232 (talk) 16:18, 7 August 2023 (UTC)

Nasa cloud cover satellite map

@No such user: The map I included previously is, in reality, much more accurate than the map you want to include simply because it's based off of actual satellite data, not some generalized man-made map with limited data points and lots of inaccuracies. I talked about the Iberian Peninsula only because that's what I'm familiar with. Only a small part of the southwest coast actually has above 3000h of sunshine (a circle around Sagres, Faro and Cadiz), not most of the peninsula... and most of the northern coast has less than 2000h (taken from sunshine recorders). Obviously it's not just Iberia. The great deserts (Kalahari, Atacama or the Sonoran and Chihuahuan deserts) are completely misrepresented into small dots of sunshine, not to mention most of Western Australia or Baja California which have above 3000h, not 2500h. The map is filled with inaccuracies, not just "minor" ones.

I don't understand why Uness232 would delete the satellite map when it's literally based off of NASA satellite recordings from 2002 to 2015. It doesn't get more official and accurate than that. Plus it also shows the ocean, hugely informative if you ask me. Average Portuguese Joe (talk) 19:31, 7 August 2023 (UTC)

@Average Portuguese Joe While I do understand the official nature of NASA data, the map is not a "cloud cover" map per se. It is data from a satellite that estimates cloud coverage. This is great in some cases, but satellite data can have biases for a lot of reasons. A good example is the small dot of near 100 percent cloudiness near NYC, visible when zoomed in. Compared to sunshine recorders, it also seems to show a bias towards east-side climates, showing Boston to be about as cloudy as Paris, while in reality there is about a 900 hour difference between the two (in fact it claims that the eastern US is about as cloud rich as Western Europe, while it is more comparable to the Mediterranean). While the data we include has to be reliable, not all reliable sources have to be included, especially if it contradicts more reliable information. Uness232 (talk) 20:14, 7 August 2023 (UTC)

References